2005 July 29 Friday
Old Age Aches And Pains Come In Clusters

Knee pain usually does not occur by itself.

Joint pain, especially in the knees, is a common complaint in older patients and can impact quality of life. A team of researchers recently set out to examine how often knee pain is accompanied by pain elsewhere in the body and whether the presence of multiple joint pain affects older patients' general health and psychological status. Their findings, published in the August 2005 issue of Arthritis & Rheumatism, indicate that most people with knee pain also have pain at other sites and these patients tend to have more limited physical function and suffer more from depression and anxiety.

Led by Peter Croft of Keele University in Keele, UK, the authors surveyed a total of 5,364 patients aged 50 years or older who were registered with 3 general practices in North Staffordshire, UK. Each participant completed a questionnaire that included a body manikin on which they shaded any areas where they had experienced pain for one or more days during the last month. Pain was categorized into regions, which included: knee, neck, hand, lower back, hip, and foot and ankle. Based on where the pain occurred, participants were then grouped into (i) those with no pain at all, (ii) those with knee pain, either alone or with pain in 1 or 2 or more locations elsewhere, (iii) those with no knee pain but with pain in 1, 2 or 3 or more locations other than the knee.

A standard health survey used to determine the influence of pain elsewhere on general health was also completed, as well as an index to measure pain and disability specifically related to the knee. Obesity, anxiety and depression, all of which are linked to widespread pain, were also measured using various scales.

Of those surveyed, slightly more than one-third (1,909) ended up in the no pain group, 41% (2,210) in the knee pain group, and 23% (1,245) in the pain elsewhere group. Decreased physical function increased with the number of pains in the body, both in the knee and elsewhere. In those with at least 3 pain regions, the subgroup that included knee pain had worse physical function. This group was also more likely to be depressed than either those with no pain at all or those who had pain in a location other than the knee, even if it was in 3 or more regions.

Knee pain occurs in pain clusters with involvement of other regions of the body.

The results indicate that knee pain does not tend to occur by itself, and that when it occurs with pain in other regions, it is associated with poorer general and psychological health. In addition, the results suggest a link between the extent of pain in the body and the impact of pain in a particular region. "We have shown that knee-specific pain and disability are actually worse in the presence of pains elsewhere than the knee, even after accounting for poorer psychological health," the authors state.

"The practical importance of our findings is that the presence and extent of pain in other sites may be an important determinant of outcome in patients who present with knee pain, just as it appears to be in those who present with back pain [as shown in previous studies]," the authors conclude. In addition, they note that managing pain in one region such as the knee (with local treatments such as physiotherapy or total knee replacement) might have beneficial effects on the general perception of pain and on the frequency and impact of pains elsewhere in the body.

Do the various pains have a common cause? Does chronic pain indicate a generally faster rate of aging?

I'd like to see a follow-up of this study with people over the age of 50 where stem cells get extracted from knees and other regions of pain and also from the blood. The goal would be to measure telomere lengths and compare them between people with and without pain to see if people with more pain are biologically older than age equivalent people who suffer less pain. Telomeres are caps on the ends of chromosomes and their lengths provide an indication of how many times a cell has divded. The more times a cell divides the shorter the telomeres get. I bet that the people with more chronic pains have shorter telomere lengths. Also, I bet that people with shorter telomere lengths will have lower life expectancies on average.

A study that looks for correlations between stem cell age and extent of aches and pains would provide evidence for whether development of stem cell treatments should gain priority in treatment of arthritis and other diseases that cause pain with age. Advocates for Strategies for Engineered Negligible Senescence (SENS) such as Aubrey de Grey argue that it would be more productive to develop rejuvenation therapies than to try to develop treatments for every disease of old age. If aches and pains are the result of cellular aging and of a lack of young stem cells to supply replacements for repair then more rapid development of rejuvenating stem cell therapies would provide better solutions for the pains of old age than surgery, anti-inflammatory drugs, anti-pain medication, and other current approaches.

For why I expect the people with more pains to have shorter telomeres and older stem cells see my previous posts "Telomere Length Indicates Mortality Risk", "Chronic Stress Accelerates Aging As Measured By Telomere Length", and "Aubrey de Grey On Stem Cell Reseeding For Aging".

By Randall Parker 2005 July 29 10:27 AM  Aging Studies
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2005 July 28 Thursday
US House Of Representatives Passes Big Energy Bill

After 5 years of trying the US House Of Representatives voted to approve an energy bill deal worked out with Senate negotiators. Cost estimates range from $13 to $14.5 billion over 10 years.

Efficiency and conservation programs would get about $1.3 billion (euro1.1 billion) of the more than $14.1 billion (euro11.8 billion) in total tax breaks over 10 years, according to lawmakers who have been briefed on the legislation worked out in negotiations between the House and Senate. About $3 billion (euro2.5 billion) in tax breaks would go for renewable energy source, mostly to subsidize wind energy.

It is hard for non-nuclear renewable tax credits to go to anything other than wind. The other options all cost way too much.

New nuclear power plants get tax credits just like wind turbines but will contribute no electricity at least for the next 10 years.

Nuclear power will also be a hedge against the possibility that the price of natural gas - which fires some of Entergy’s other plants - will continue to rise. The downside, Hebert said, is that the plants take a long time to permit and build. If Entergy is first in line to build a new plant, as he hopes, the process could take a decade or more.

That’s where the energy bill comes in. It extends the coverage of the Price-Anderson Act, which limits the liability for current nuclear-power-plant accidents to $9 billion each, to new plants. Its "standby support insurance" will ensure the first six plants to go through federal and state licensing processes can recover up to $500 million for delays caused by regulatory logjams or lengthy legal challenges during construction.

It also provides production tax credits for the first half-dozen plants, giving them the same incentives as power produced by wind turbines, and it has $1.2 billion in tax write-offs to help offset the costs of funds needed to ensure that the plants can be safely torn down, or "decommissioned."

How much of that 10+ years of delay in putting up nuclear plants comes from the regulatory approval period and how much from the construction period? Anyone know? Surely it should not take 10 years to build something.

New nuclear plants get a tax credit on electric power for the first 8 years of operation.

* Offers $2 billion in federal insurance to cover delays in building 6 new nuclear power reactors.

* Creates production tax credit for new nuclear plants at a rate of 1.8 cents per kilowatt hour for electricity produced over an eight-year period.

Wind gets a similar per kilowatt hour tax credit. the 1.9 cent per kilowatt-hour tax credit for renewables in this bill will cut the cost of a Maine wind farm by 30%.

Without the tax credit, the $68 million wind development project would be 30 percent more expensive, according to Peter Gish, managing director of UPC Wind Partners, Evergreen's parent company.

The wind farms have to get built between the beginning of 2006 and the end of 2008 to qualify. Apparently this extends a tax credit that had just expired. So all those existing wind farms that people point to as examples of the competitiveness of wind were built with hefty tax credits. I wonder how many of the reports comparing costs of different energy sources (e.g. the recent report in The Economist that someone brought up in comments of a another post) assume those tax credits in their calculations.

Of course, to be fair to wind power the coal burners are allowed to emit pollutants that produce external costs that do not show up in the price of coal burner electricity.

Also, how long does wind's tax credit last? 8 years for nuclear is not that long since nuclear's capital cost takes decades to pay back and nuclear plants can last for 50 or more years. My guess is that wind is getting the bigger tax credit.

Most of the costs come in the form of tax credits and deductions.

The $11 billion net cost of the tax package plus the $2 billion direct spending comes to a relatively modest (for an energy bill) $13 billion over 10 years, with further costs depending on future appropriations.

Production credits for a large assortment of industries are to be expected since industries make donations in elections and employ people back in districts. By in my view funding of energy research would provide much bigger pay-offs in the long run.

Why should coal plant operators get a tax credit for not polluting us?

In pursuing that goal, Boucher said more than $3 billion dollars in tax benefits and incentives will be utilized to encourage electric utilities to use a new generation of clean-coal technologies that will enable coal to be burned almost as cleanly as natural gas.

US House Speaker Dennis Hastert enthuses about the prospects of producing ethanol that probably takes more energy to produce than exists in the resulting ethanol.

"In addition, this bill helps us reduce our dependence on foreign oil by unleashing the power of the American farmer.

"This legislation includes an historic Renewable Fuel Standard, which will result in the doubling of the use of clean- burning and renewable ethanol. The production and use of 7.5 billion gallons of ethanol by 2012 will displace over 2 billion barrels of crude oil. America has a strategic reserve of motor fuels in the cornfields of Illinois, the rice fields in California, and the cane fields of Florida, and it's time we tap it.

"This legislation also helps alleviate the hidden tax on American consumers, farmers, small businesses and manufacturers that comes in the form of higher natural gas prices. Increased natural gas prices have had an adverse impact on the American economy for too long. Several provisions in H.R. 6, including the streamlining of the LNG infrastructure permitting process and the inventory of America's off-shore resources, are significant steps toward ensuring that our Nation has an adequate and affordable supply of natural gas.

Ethanol production will rise to 7.5 billion gallons per year from the current 4 billion per year. More waste. More happy corn farmers. Archer Daniels Midland's board of directors must be happy. Refiners get the mandate to buy the ethanol. You'll pay at the pump.

Aside: I like the extension of daylights savings time by a month because I'd rather have more sunlight at the end of the day than at the beginning of it. So I've always disliked turning back the clock in the fall.

One energy investment banker expects little difference on the supply side as a result of this bill.

"The energy bill is not going to make a meaningful difference in U.S. supplies," said Steve Enger, an analyst at Petrie Parkman & Co., an energy investment bank in Denver.

Measures in the bill to increase fossil fuels energy production will make little difference in the long run. Oil not extracted now will sit there waiting for future use. Therefore the deletion of an opening of Alaska's Arctic National Wildlife Refuge probably doesn't hurt much. ANWR probably will be opened eventually as oil becomes more scarce.

Only measures that accelerate the development of sustainable energy sources (wind, nuclear, solar, etc) provide a long term benefit. Therefore the bill's subsidies for the nuclear power industry will make a difference by bringing nuclear power back to life. Also, the wind power subsidies might make a difference in the growth of wind power. But the bill strikes me as a big opportunity loss for accelerating research on 4th generation nuclear plants, photovoltaics research, and battery research.

The bill imposes requirements for more efficient appliances. That'll help on the demand side. But passive solar building designs and better insulation do do much more to lower demand.

By Randall Parker 2005 July 28 04:30 PM  Energy Policy
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2005 July 26 Tuesday
Should Pregnant Drug Abusers Be Institutionalized?

A single hit of methamphetamine causes brain damage in fetal mice.

A single prenatal dose of methamphetamine – commonly known as speed – may be enough to cause long-term neurodevelopmental problems in babies, say University of Toronto researchers.

In research published in the August issue of Free Radical Biology and Medicine, U of T pharmacy and pharmacology professor Peter Wells and his colleagues determined that exposing pregnant mice only once to methamphetamine led to delivery of offspring with long-term neurodevelopmental problems, including reduced motor co-ordination. Methamphetamine is a potent and addictive stimulant.

"We've known for a while that meth abuse during pregnancy is associated with low birth weight, cleft palates and other malformations but this is the first research demonstrating that even a single exposure can cause long-term damage," says Wells. "It's pretty remarkable that a single low dose can have such an effect.

"It's an important finding, given the increasing use of club drugs among women of childbearing age. It has clinical implications, because it shows that the fetus is exquisitely sensitive."

The developing fetus appears to be vulnerable to DNA damage from methamphetamine exposure because it hasn't yet developed the enzymes that protect it against free radicals – highly activated, destructive oxygen molecules that have been implicated in cancer and neurodegenerative diseases, says Wells. This vulnerability lasts from the embryonic stage through the later fetal period, times when organ structures and mental functions develop.

Should pregnant women who use crystal meth or any form of methamphetamine get locked up in institutions until their babies are born? What if they intend to breast feed? Should they remain locked up until the babies are weened off breast milk?

Meanwhile meth use is a growing problem and not just in rural areas.

According to a survey of law enforcement organizations conducted by the National Association of Counties and released this month, 87 percent of the 500 agencies that participated reported increases in meth arrests in the past three years.

Agencies in Indiana, California, Minnesota, Florida and Ohio reported the number of meth-related arrests had doubled in this time. Iowa, Mississippi, Illinois and North Dakota reported increases of 90 percent or greater.

Is reproduction such a basic sacred right that the state should not dare interfere with it? If drug users want to pop out the babies for the state and foster homes to raise? Should people be permitted to engage in reproductive practices that lead to premature births and brain damaged babies who grow up to be brain damaged adults and wards of the state?

Some commenters raised objections to the tone of my previous post "Low Birth Weight Baby Development Problems Raise Ethical Question". Well okay then. Does the state have no moral right to intervene in the reproductive process? If technological advances make home crystal meth production cheap and easy and lots more fertile women become crystal meth abusers should the state take no steps to enforce safe and responsible reproductive practices?

I see this as linked to an even bigger coming question: When technology advances to the point where people can tinker with the genes of their offspring should the state state limits on how much aggressiveness or other qualities parents should be allowed to genetically engineer into their kids? Does the "unnatural" aspect of genetic engineering provide the state a unique reason to intervene and regulate reproduction where it should not have that power absent that "unnaturalness" that comes from the use of genetic engineering technoloogies?

Some might want to allow state regulation of reproduction involving genetic engineering while otherwise opposing state regulation of reproduction as a violation of basic human rights. But if genetic engineering makes reproduction sufficiently unnatural as to become regulable then why don't all the technologies used to keep premature babies alive have the same effect? After all, the ultimate baby preserving technology which will be developed to keep premies alive will be the complete artificial womb. Once we have artificial wombs then many of the spontaneously aborted (and probably genetically defective) fetuses will not get aborted unless someone flips a switch on the artificial womb. A decision previously made by natural processes which are the product of natural selection or by God (take your pick based on your beliefs - but I'm with Darwin) will be under the conscious control of human minds - just as the decision to put a premie in an incubator is now a human decision.

So when should the state regulate reproduction? Why? Are you a utilitarian? Do you think that people have the right to produce offspring they can't afford to raise and then expect the state (i.e. the taxpaying rest of us) to pay for? Do you think that state intervention against reproducing druggies is a moral and practical necessity or an immoral interference in basic human rights?

By Randall Parker 2005 July 26 03:48 PM  Bioethics Debate
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2005 July 25 Monday
Low Birth Weight Baby Development Problems Raise Ethical Question

Should radical measures be employed to save low birth weight premature infants?

Asthma, cerebral palsy, vision and hearing disorders, low I.Q., poor school performance and social difficulties are among the problems described in The Journal of the American Medical Association by doctors at Rainbow Babies and Children's Hospital in Cleveland. Such disabilities were far more common in the children born prematurely than in normal-weight children from similar backgrounds. For example, 38 percent of those born prematurely had I.Q.'s below 85, as opposed to 14 percent of the normal-weight children. Among the premature, 21 percent had asthma, compared with 9 percent of those with normal weight.

The babies looked at in this study weighted 2.2 lbs or less at birth.

A look at 219 such children born between 1992 and 1995 found 14 percent had developed cerebral palsy, 21 percent had asthma, 38 percent had an IQ under the threshold denoting retardation, 47 percent had poor motor skills, 10 percent had very poor eyesight, and roughly two-thirds were characterized as having "poor adaptive functioning" and "functional limitations," the study said.

Maureen Hack, an expert on premature births at Case Western Reserve University, led the study published in the Journal of the American Medical Association.

About 23,000 very low birth weight babies are born in the United States every year.

Of the 23,000 babies born in the United States in 2002 weighing between 1.1 to 2.2 pounds (500 and 999 grams), 70 percent survived, according to the report.

Check out the total percentages for different ways of categorizing the problems with low birth weight premies.

  • Functional limitations, such as difficulty seeing, hearing, speaking, or communicating (64% versus 20%, OR 8.1; 95% CI 5.0-13.1)
  • Compensatory dependency needs, such as a regularly prescribed medication (48% versus 23%, OR 3.0; 95% CI 1.9-4.7)
  • Need for services above those routinely required by children, such as special school arrangements (65% versus 27%, OR 5.4; 95% CI 3.4-8.5).
  • Advances in biomedical technology lead to increases in the number of very premature babies that survive and have problems.

    A JAMA editorial refers to Hack's findings as ``disappointing news.'' While more babies are surviving at low weights, the long-term outcome has not improved in the last decade or so, the writers say. In fact, they say, the proportion may have worsened as more babies survive.

    Hack, though, said she doesn't see these numbers as disappointing. Only 8 percent of the low-birth-weight babies were unable to walk without help at age 8, which means that 92 percent were walking on their own. And just 6 percent had trouble feeding themselves, while only 7 percent were unable to socialize or play with others.

    Hack said one surprising finding was that even low-birth-weight babies with normal IQs were prone to have trouble in school.

    ``In the past, we looked at a normal IQ over 85 and we expect the child to do fine,'' she said. ``But we're finding they also have problems at school. Even children who are basically functioning OK do have substantial learning problems.''

    There is an old saying about a box being either half empty or half full. Hack thinks it good news that only 8 percent of these premies can't walk at age 8. I see it as a terrible tragedy.

    Also, Hack is wrong to be surprised at the number of premies who have trouble learning. The intelligence level "g" matters (PDF format). If 38 percent are retarded then a large percentage are above the retardation level but still well below the white average IQ of 100. Put that 100 IQ into perspective. One needs 120+ IQ to work at the more demanding jobs such as doctor, lawyer, veterinarian, engineer, or middle manager. The bulk of these premies are not headed for even moderately above average IQ jobs such as clerk, retail store manager, or mechanic. A large fraction of them - perhaps even a majority - will spend their lives as wards of the state.

    These results raise the question of whether low weight birth babies should be treated with such extraordinary measures to keep them alive. I would be interested in hearing views from readers in the comments section.

    Also, note that while advances in biotechnology will eventually lead to the development of artificial wombs which a premie baby could be transferred to at birth do not expect such technologies to eliminate all the medical problems reported above. Some of the premature births are happening because the developing fetus has already developed problems. Some of the premature births are due to genetic flaws. Others are due to toxic exposures that happened while still in the mother's womb. So at birth the defects are already present.

    Update: Also see my previous post "Premature Birth Produces More Lasting Brain Effects In Boys".

    By Randall Parker 2005 July 25 11:39 AM  Bioethics Debate
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    2005 July 22 Friday
    Genetically Engineered Mice Age More Rapidly Due To Mitochondrial Mutations

    Tomas A. Prolla of the University of Wisconsin found that mice genetically engineered to undergo more rapid mutation of mitochondrial DNA aged at a much more rapid rate and experienced cell loss, especially in cells that divide rapidly.

    Using mice genetically altered to have a deficiency in a protein that proofreads mitochondrial DNA and thus accumulate genetic mutations at a higher rate than unaltered mice, the group led by Prolla found evidence that programmed cell death, known as apoptosis, was greatly accelerated. The altered mice exhibited obvious hallmarks of aging - including graying, hair loss and atrophied muscle and bone - at a pace much faster than the typical laboratory mouse.

    "It's like a broken spellchecker," says Prolla. "By introducing a malfunction in the (genetic) proofreading domain, these mutations accumulate much more rapidly."

    The new work lends support to one of the two leading theories of how animals, including humans, grow old and die. It supports the theory that apoptosis or programmed cell death underpins aging. A competing theory holds that oxidative stress - the body's reaction to oxygen and the production of reactive, cell-damaging molecules known as free radicals - is responsible for the aging process.

    According to the new Science report, markers of oxidative stress did not parallel the accumulation of mitochondrial genetic mutations. Instead, the group found evidence that indicated accelerated cell death, especially in tissues characterized by rapid turnover of cells, occurred as mutations mounted in the mitochondrial DNA.

    "We found no evidence of oxidative stress," Prolla explains. In fact, the team noted less oxidative stress in some tissues - the liver, for example - which suggests that accumulated genetic mutations in mitochondria slow metabolism. In turn, that change prompts cells to produce fewer of the reactive free radical molecules.

    The symptoms of aging become pronounced with the loss of some critical cells, notably adult stem cells from some tissues and that are essential for replacing cells that die. "If these stem cells are lost, tissue structure and the ability of tissue to regenerate are impaired," Prolla explains. "We have observed that in tissues like bone marrow, intestine and hair follicles."

    The altered mice used in the study were created by manipulating mouse embryonic stem cells to produce mice with the defective DNA proofreading protein. The mice develop normally, but age rapidly and develop such things as age related heart dysfunction, hair loss, loss of immune cells, anemia, and loss of male germ cells that lead to reduced sperm production and infertility.

    We need constant supplies of replacement cells. Aging of stem cell reservoirs in the body are especially harmful because stem cells divide to produce a very large range of replacment cell types throughout the body.

    Prolla thinks an obvious next step would be to genetically engineer mice to have a lower rate of accumulation of mitochondrial DNA mutation.

    Prolla suggests that new studies of mice engineered to have fewer than normal mitochondrial DNA defects or improved mitochondrial function may pave the way for strategies to retard aging. "The idea would be to reduce the level of cell death and improve function. If that pans out, then we can begin to think about pharmaceutical interventions to retard aging by preserving mitochondrial function."

    Stem cell therapies could replace the stem cells lost due to aging. That would provide enormous benefit. Also, growth of new replacement organs would allow entire aged organs to be replaced by youthful organs. But we also need the ability to send in gene therapy to repair or replace the mitochondrial DNA of aged cells. Look at brain cells. Unless you want to entirely forget the past you don't want to just replace old nerve cells because those old cells hold memories and have been conditioned to perform various tasks.

    Mitochondrial DNA is the genetic Achilles Heel of eukaryotic cells (and human cells are eukaryotic because they have specialized compartments such as the nucleus and mitochondria). Eukaryotic cells have mitochondria which are sort of like mini-cells within cells. These mini-cells (usually called organelles) are specialized to carry out the task of breaking down sugar to produce energy molecules (ATP and NADH) used elsewhere in cells to provide energy to carry out just about all cellular tasks. The problem with mitochondria is that they have their own DNA which is exposed to free radicals generated by the breakdown of sugars. Damage to the DNA by those free radicals probably cause the mitochondrial DNA to accumulate mutations at a faster rate than nuclear DNA.

    Biogerontologist Aubrey de Grey proposes the development of modifications of the 13 mitochondrial DNA genes to allow those genes to be moved to the cell's nucleus. This would reduce the rate at which the mitochondrial genes get mutated and therefore delay the decline of cellular energy production as cells age. Cells with better protected mitochondrial genes would continue to produce energy for many more years (perhaps decades longer) and therefore general cellular aging would be much slowed. This latest report provides evidence that strongly suggests Aubrey's proposal would help.

    Hopefully Prolla's report will be seen by the scientific community as a reason to do the work necessary to genetically engineer mitochondrial genes to move them into the nucleus.

    By Randall Parker 2005 July 22 02:09 PM  Aging Studies
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    Facial Appearance and Smell Produce Conflicting Desires For Mates

    Women normally (with exceptions) prefer the smell of men who are immunologically different from them. The desire for mates who have differences in sequences in Major Histocompatibility Complex (MHC) genes is probably the result of selective pressures to give offspring more genetic variations against diseases to increase the odds that at least some of a woman's offspring would survive. But Craig Roberts of the University of Liverpool found that women prefer the faces of men who have more similar MHC genes.

    Previous research on smell suggests that humans prefer odours from potential partners who are genetically dis-similar. But new research in which women rated the facial attractiveness of men suggests the exact opposite. So sight and smell appear to be giving contradictory messages about which partners to choose.

    The curious thing about this effect is that MHC variations are tied to facial shape variations. Are the genes for each located on the same chromosome? Do MHC variations cause facial shape differences?

    “It’s a subtle effect,” says Craig Roberts of the University of Liverpool, who led the team which made the discovery. “We’re not saying it’s something that rules who we find attractive.”

    Roberts and colleagues recruited 92 women and 75 men, and recorded differences in their MHC by analysing DNA from blood samples. Then each woman was asked to rate photographs of six men, three with similar and three with different MHC.

    The results showed that, visually, the women preferred men with similar MHC. The preference applied both to long and short relationships, but was strongest for potential long term relationships.

    Amerinds (a.k.a. indigenous peoples of the Americas) have fewer MHC variations than Europeans and Europeans have fewer than Africans (and this fact majorly contributed to the massive die-offs of Amerinds when the first European explorers showed up carrying many diseases that were new to the Americas). It would be worth investigating whether the same patterns of attraction to the opposite sex with similar or different MHC genes are found in Africans, Europeans, and Amerinds.

    Since the Amerinds have fewer MHC variations and less selective pressure was present for MHC variations did they also experience less selective pressure for preference to mate with people who are immunologically different? Do the Amerinds have perhaps even indifferences to smell differences caused by MHC differences? Is the opposite the case among Africans? More generally, do particular MHC types which are found in some races or sub-racial groups produce smells that are either extremely desirable or extremely revolting in some other racial group?

    By Randall Parker 2005 July 22 12:33 PM  Brain Sexuality
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    2005 July 21 Thursday
    Hallucinated Voices Male Because Male Voices Easier To Imagine

    Female voices are more complex and hence people who hallucinate voices tend to hallucinate male voices more often than not.

    Dr Michael Hunter's research at the University of Sheffield says that male voices are less complex to produce than female.

    As such, when the brain spontaneously produces its own "voices", a male voice is more likely to have been generated.

    Among both men and women, 71% of such "false" voices are male.

    Since male voice hallucinations are harder for the mind to make does average type of voice heard differ as a function of intelligence level? When smarter people hallucinate do they hear female voices at higher rates than dumber people who hallunicate voices? Also. do people with perfect pitch or other musical abilities hear female voices more often? After all, they have more developed abilities for imagining complex voices.

    By Randall Parker 2005 July 21 11:06 PM  Brain Sex Differences
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    2005 July 20 Wednesday
    Rats Show Cocaine Reduces Ability To Modify Learned Behavior

    Addictive drugs are bad for the brain.

    Researchers working with rats have zeroed in on the brain circuitry mechanism whose disruption contributes to the impulsive behavior seen in users of cocaine as well as other psychostimulant drugs. The same circuitry has been implicated in such disorders as schizophrenia, depression, and post-traumatic stress disorder, wrote the researchers.

    Yukiori Goto and Anthony A. Grace of the University of Pittsburgh described their findings in the July 21, 2005, issue of Neuron. In their studies, they sought to understand the effects of cocaine sensitization on the connections between two higher brain regions--the prefrontal cortex and the hippocampus--and the nucleus accumbens, which is the region in the limbic system involved in processing reward behavior. The prefrontal cortex is involved in processing information, and the hippocampus is involved in learning and memory.

    The connections to the nucleus accumbens seem to be bidirectional, said the researchers, and the interactions with the prefrontal cortex and hippocampus could affect the "plasticity" of connections in the neurons of the nucleus accumbens. This means that disruptions to the normal connections could affect behavior.

    The researchers' electrophysiological studies of the effects of cocaine on this circuitry demonstrated that the drug did disrupt this normal plasticity. They found that the cocaine induced abnormal enhancement of neuronal connections--a phenomenon called long-term potentiation (LTP).

    The researchers also performed behavioral studies on the cocaine-sensitized rats, to explore the behavioral effects of this disruption. In these studies, they placed the rats in a plus-shaped maze. The rats were taught that in response to a visual cue they should turn left or right toward one arm or the other of the maze to obtain a piece of cereal.

    Goto and Grace found that, while the cocaine-sensitized rats learned the correct response strategy faster than normal rats, they were significantly less able to change strategies when they were required to ignore the cue and always make a left or right turn to receive the reward.

    "Thus, although abnormally induced LTP by psychostimulants at limbic inputs might not interfere with learning a response strategy, it may reduce the capacity of these animals to consider alternate response strategies," concluded Goto and Grace. "In this way, the disruption of synaptic plasticity by cocaine sensitization may contribute to the affective- and context-inappropriate impulsive behaviors that are characteristic of drug addiction."

    A drug that increases impulsive behavior in its users creates problems (e.g. crime, poorer relations with friends, neighbors, familiies) for the rest of us. Cocaine addicts have a harder time modifying some behavior or lesson already learned. One can imagine how that would cause them to get stuck in ruts of repetitive behavior that is destructive to themselves and to other people..

    Cocaine addicts are more oriented toward pleasure.

    “It may explain why cocaine addicts are oriented towards pleasure rather than other goals, and have an impaired ability to make decisions. It could be why addicts go back to taking more of the drug and ex-addicts often become addicted again faster than those who have never taken it,” says Grace

    Drugs that reduce cognitive competence increase the costs that users impose on the rest of us while at the same time the drugs make the users less productive. Users simultaneously increase the costs they impose while giving less in return. We need treatments that cure addictions. We also need better drugs that make us more adaptive, not less.

    By Randall Parker 2005 July 20 04:28 PM  Brain Addiction
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    2005 July 19 Tuesday
    South Korea Sees Bigger Role For Nuclear Power

    A South Korean government official says South Korea's reliance on nuclear power is slated to increase substantially.

    About 60 percent of South Korea’s energy is expected to come from nuclear power stations in three decades, a drastic rise from its current level of 40 percent.

    The Ministry of Science and Technology (MOST) said yesterday it predicts the nation’s dependency on nuclear power will soar thanks to the next-generation nuclear facilities under construction.

    ``If we cannot find a new energy source to replace today’s fossil fuels, we have no choice but to raise our reliance on nuclear power,’’ MOST director general Kim Young-shik said.

    My guess is that 40% of South Korea's electricity, not of its total energy comes from nuclear power. The article probably got it wrong (perhaps due to a translation error).

    The South Koreans are a smart bunch of people and they are betting on nuclear power. They already get a lot of power from nuclear reactors and also are actively engaged in 4th generation nuclear reactor research and fusion reactor research.

    I agree with those who suspect the Saudis are greatly exaggerating their oil reserves. A recent president of Aramco disputes the official Saudi Arabian line on the expandability of Saudi production. I strongly suspect the oil era does not have many decades left to run (and the global warming debate is based on a big false assumption about oil reserves). I write about energy policy because I see energy as a big problem we need to solve sooner, not later.

    Nuclear power is expected to maintain its same percentage of total power as the total consumption of energy grows.

    Worldwide, there are 440 nuclear power plants, and 24 more are under construction, according to the International Atomic Energy Agency in Vienna.

    New nuclear stations and an extended life for existing ones will offset the closure of aging plants to keep the share of nuclear energy in the global power capacity mix at 12 percent in a decade, according to estimates from PricewaterhouseCoopers.

    The two wild cards in my opinion: a decline in Saudi oil production and breakthroughs in solar photovoltaics production costs.

    Two thirds of recent nuclear plant completions have been in Asia.

    Most reactor building is in countries that are new to nuclear power. There are 25 reactors under construction in 10 countries, according to the World Nuclear Association, an industry group, and another 112 are planned or proposed.

    Interest is keenest among expanding Asian economies. Of the last 30 nuclear reactors to have connected to the power grid, 20 have been in Asia. India, where nuclear power accounts for 2.8% of electricity production, has nine reactors under construction. It wants to boost the amount of electricity generated by nuclear plants by 100 times by the middle of the century.

    Nuclear power's biggest growth region is East Asia.

    The authority idled the reactor in northern Alabama in 1985 because its physical layout didn't match architectural drawings. Restarting Browns Ferry 1 will cost about US$1.8 billion. New plants may be built within six years, Senate Energy Committee Chairman Pete Domenici, a New Mexico Republican, said in April.

    Nuclear plants may contribute about 200 gigawatts of the 4,800 gigawatts of new capacity needed until 2030, according to the IEA. European countries will add more than 40 gigawatts of nuclear capacity by 2030, the IEA said.

    Nuclear capacity will increase in Asia to 8 percent of the region's total in 10 years, from 5 percent now. China, the world's second-largest electricity consumer after the US, plans to add about 30 gigawatts of nuclear generation by 2030, while Russia could add another 22 gigawatts. Korea may add 17 gigawatts and Japan about 14 gigawatts, according to the IEA.

    Note above the absolutely huge growth in total electric generation capacity forecast in the next 25 years. My guess is that oil will stay expensive and perhaps rise further. This will shift demand away from oil toward natural gas and that will keep natural gas expensive. So nuclear will compete with coal and wind and in the longer term with solar. But wind may win out in areas which ban nuclear and coal power plants.

    A study by the UK's Royal Academy of Engineering last year showed that one unit of gas generation costs four cents per megawatt-hour, compared with 4.3 cents for a nuclear plant, 4.7 cents for a coal-fired plant and 6.7 cents at a wind park.

    Total costs of producing nuclear power, including construction and decommissioning, are likely to be US$46 per megawatt-hour in 2010, less than the US$50.80 for a gas-fired station and the US$54.39 for a coal-fired plant, a study published in March by UBS AG said. The calculation assumes oil prices fall to US$32.50 a barrel, after 2007. If oil prices slid below US$28, nuclear wouldn't be competitive against gas, UBS said.

    If coal plant operators were forced to reduce emissions now then my guess is coal would cost at least as much as wind power and perhaps more. Though emissions control technology advances in the future will reduce the cost of emissions reduction I still expect coal emissions reduction to remain fairly expensive. So far in the United States the coal burners have managed to delay tougher regulatory standards on emissions. But I expect the American public to attach increasing importance to cleaner environments. As living standards rise people place greater value on esthetic and health considerations. So coal plant lobbyists are eventually going to lose against public opinion.

    My guess is that nuclear power in East Asia is going play out in a manner similar to the French pattern. The East Asia peoples won't take environmentalist objections seriously and instead will see nuclear as the cleanest, most reliable, and cost effective alternative to fossil fuels. The future of nuclear power in the United States is less clear. While some environmentalists are having second thoughts about their opposition so far coal looks set to meet the bulk of future growth in US demand with wind and nuclear playing smaller roles. At some point the price of photovoltaics will plunge and solar power may become the biggest energy providers. But until then nuclear looks like the most cost effective cleaner alternative to coal.

    By Randall Parker 2005 July 19 06:52 PM  Energy Policy
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    2005 July 18 Monday
    Photovoltaic Concentrators To Reach Cost Effectiveness In Few Years?

    How close are we to cost effective photovoltaic cells?

    Golden, Colo. — Solar concentrators using highly efficient photovoltaic solar cells will reduce the cost of electricity from sunlight to competitive levels soon, attendees were told at a recent international conference on the subject. Herb Hayden of Arizona Public Service (APS) and Robert McConnell and Martha Symko-Davies of the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) organized the conference held May 1-5 in Scottsdale, Ariz.

    "Concentrating solar electric power is on the cusp of delivering on its promise of low-cost, reliable, solar-generated electricity at a cost that is competitive with mainstream electric generation systems," said Vahan Garboushian, president of Amonix, Inc. of Torrance, Calif. "With the advent of multijunction solar cells, PV concentrator power generation at $3 per watt is imminent in the coming few years," he added.

    We have seen steady progress in photovoltaic concentrator technology. We are working with advanced multijunction PV cells that are approaching 38% efficiency, and even higher is possible over time. Our goal is to install PV concentrator systems at $3 per watt, which can happen soon at production rates of 10 megawatts per year. Once that happens, higher volumes are readily achieved," Hayden, Solar Program Coordinator at APS, said.

    Growth in the photovoltaic (PV) concentrator business was reflected in the conference attendance, three times that of the 2003 version. This rapid growth was attributed to recent PV concentrator installations and sales forecasts along with excitement created by new solar cell efficiencies approaching 40%. At the conference, NREL announced a new record efficiency of 37.9 percent at 10 suns, a measure of concentrated sunlight. Soon thereafter Boeing-Spectrolab, under contract to NREL and the Department of Energy, surpassed the NREL record with 39.0 percent at 236 suns announced at the European photovoltaic conference in Barcelona, Spain. The efficiency of a solar cell is the percentage of the sun's energy the device converts to electricity.

    Photovoltaic (PV) concentrator units are much different than the flat photovoltaic modules sold around the world; almost 1,200 megawatts of flat PV modules were sold last year. PV concentrators come in larger module sizes, typically 20 kilowatts to 35 kilowatts each, they track the sun during the day and they are more suitable for large utility installations.

    Those 1,2000 megawatts of flat PV modules sold last year are equivalent to 1 nuclear power plant running only part of the day. So maybe they equal a third or a quarter of a nuclear power plant. However, see the following article where one person is quoted estimating 14,000 megawatts of PV sold in the last year in the world.

    Note the concentrator installations are more complex because they have mechanical components to keep the photovoltaics pointed at the sun. This is probably not practical for home roof photovoltaics due to materials, installation, and maintenance costs. Then will large commercial photovoltaics electric power generator facilities become cost effective before residential solar power?

    Update: The San Francisco Chronicle has an article about growing venture capital funding of photovoltaics start-ups. Venture capital start-ups are pursuing flexible and cheap plastic photovoltaics.

    Nanosys and Nanosolar in Palo Alto -- along with Konarka in Lowell, Mass. -- say their research will result in thin rolls of highly efficient light-collecting plastics spread across rooftops or built into building materials.

    These rolls, the companies say, will be able to provide energy for prices as low as the electricity currently provided by utilities, which averages $1 per watt.

    Note that the $3 per watt hope from the first article is 3 times the $1 watt figure to compete against utilities.

    The Sand Hill Road venture capitalists are interested in photovoltaic materials that require far less capital equipment to produce.

    "Silicon is very capital-intensive. You don't need a clean room for plastic power where capital costs are one-tenth of silicon," said Raj Atluru, managing director at the venture capitalist firm of Draper Fisher Jurvetson in Menlo Park, a major investor in Konarka.

    Cheap solar power is inevitable. But when?

    By Randall Parker 2005 July 18 12:17 PM  Energy Solar
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    2005 July 13 Wednesday
    Bioterrorism Attack On Food Supply Modelled By Stanford Researchers

    Stanford University researchers Lawrence M. Wein of the Graduate School of Business and Yifan Liu of the Institute for Computational and Mathematical Engineering have created a model of the likely effects should terrorists put botulinum toxin into a single milk delivery tanker before it delivers its load to a milk processing plant.

    STANFORD GRADUATE SCHOOL OF BUSINESS — A mere 4 grams of botulinum toxin dropped into a milk production facility could cause serious illness and even death for 400,000 people in the United States. Investments that would cost the public only 1 cent more per half-gallon of milk could prevent this nightmare scenario, according to Lawrence M. Wein of the Stanford Graduate School of Business.

    Wein, the Paul E. Holden Professor of Management Science, has been conducting a series of studies on the effects of various potential terrorist activities in United States. Not only milk, but soft drinks, fruit and vegetable juices, processed tomato products, and even grains—anything that goes through large-scale storage and production and rapid distribution—could be at risk for such an attack, with catastrophic consequences for the American public, Wein says in his most recent study, conducted with Yifan Liu, a PhD candidate at the Institute for Computational and Mathematical Engineering at Stanford University.

    In the case of milk, says Wein, all it would take is for someone to obtain a suitable strain of botulinum toxin—the most poisonous substance known to humans—from an overseas black market lab, grow it in culture, and pour it into an unlocked milk tank or milk truck. From there, the contaminated milk would make its way into large processing silos, where it would poison at least 100,000 additional gallons. Only a fraction of the toxin would remain active after pasteurization, but according to Wein's mathematical model, that could be enough to infect the approximately 400,000 people who would drink the milk. "Only 1 millionth of a gram is enough to poison an adult," says Wein, "and there would be more than that per person remaining in the distributed milk to do the job."

    Wein and Liu’s paper was published in the July 12 issue of the Proceedings of the National Academy of Sciences (PNAS) accompanied by an unusual editorial addressing some of the debate on scientific research vs. national security that has arisen since pre publication copies were circulated to a limited list of academics.

    Based on their mathematical models of current distribution of milk, Wein and Liu estimate that within 48 hours of ingesting contaminated milk, consumers would begin to display symptoms. If authorities were able to notify the public within the subsequent 24 hours to stop drinking milk (an ambitious time period), the contamination could be reduced. However, of those eventually exposed, "about half would die," says Wein. The death toll would be high (as much as 50,000 he estimated), due to the current insufficient supply of ventilators and antitoxins in the U.S. medical system.

    However, an ounce of prevention is worth a pound of poison, says Wein, who last September presented his findings on the case of bioterrorism and milk to the Assistant Secretary of Public Health Preparedness and several members of the Department of Homeland Security.

    Wein calls for the FDA to make current volunteer safety guidelines mandatory, such as requiring that milk tanks and trucks be locked and that two people be present when milk is transferred from one stage of the supply chain to the next.

    Before releasing milk into silos, milk-tank truck drivers should be required to employ a new 15-minute test that can detect the four types of toxins associated with human botulism. Drivers currently are required to wait for an antibiotic residue test and the toxin test could be conveniently accomplished at the same time. "A single set of tests can be performed on each 5,500 gallon truck at a cost to milk producers that would raise consumer prices only several cents a gallon," says Wein. "We the public need to ask ourselves whether the elimination of this catastrophic threat is worth a one cent increase in the cost of a half-gallon of milk."

    Changes made in voluntary pasteurization processes since the 9/11 terror attacks may mean that Wein and Liu’s original calculations of the human toll should be lowered, said Wein. The PNAS editorial, signed by Bruce Alberts, president of the National Academy of Sciences (NAS), agreed but argued that the issues raised by the paper are still of value to both academics and security agencies. “There is everything to be gained by alerting the public and state governments to the dangers so they can help the federal government in its ongoing, highly laudatory attempts to reach 100 percent compliance” with pasteurization processes that will protect the milk supply.

    In the original paper (which has free web access) the researchers say a few major inputs into their model have large levels of uncertainty associated with them.

    There are also three aspects of the model that have not been discussed in the open literature, although presumably studies can and perhaps have been performed: the inactivation rate attained by pasteurization, the specificity of an ELISA test in milk, and the release size that a terrorist organization is capable of. Such studies would allow our results to be sharpened considerably. The dose–response curve, pasteurization inactivation rate, and terrorists' release-size capabilities each contain several orders of magnitude of uncertainty, and together they essentially determine the release threshold required to achieve a sufficiently high milk concentration. There is much less uncertainty about how many people would drink this contaminated milk.

    One big question has to do with the effectiveness of pasteurization at deactivating the toxin.

    Taken together, we have a reasonably accurate estimate of the number of people who could be poisoned but a very poor estimate of how much toxin is required to cause a large outbreak. The main uncertainties related to the number of people who could be poisoned are how quickly the attack would be detected via early symptomatics and how quickly and completely consumption would be halted: we optimistically assumed that consumption is halted instantaneously and completely within 24 h after the early symptomatics are detected, even though it took several weeks to identify the source of the two large but more subtle Salmonella outbreaks in the dairy industry (26, 27). Even if the reducible uncertainty resolves itself favorably (e.g., heat pasteurization inactivates 99% of toxin rather than 68.4%), a catastrophic event is not implausible, and the way forward seems clear: invest in prevention, investigate inactivation processes that do not affect nutrition or taste and, most importantly, develop and deploy a sub-45-min highly specific in-process test.

    Check out a graph from the paper that shows rate of poisoning as a function of initial dose added to a milk tanker. Note that the highest dose modelled is 1 kilogram. Terrorists who managed to contaminate multiple tanker trucks going to multiple mlk processing facilities could poison a much larger number of people.

    Note the key role of pasteurization in reducing the extent of poisoning. Imagine some other food has similar characteristics to milk in that it gets processed at large facilities and rapidly distributed but which does not get pasteurized. Contamination of such a food would deliver a much larger portion of the toxin to the public.

    Automated centralized food distribution systems greatly reduce costs. But they also introduce central points of vulnerability. However, on the bright side the big food production facilities also introduce central points for testing and for safety measures to protect foods and neutralize toxins.

    One other point: Technologies that increase the shelf life of foods will have the effect of reducing the scale of bioterrorism attacks on food. If food goes bad quickly people will buy it more often and eat it sooner. Fresh milk will get consumed pretty quickly for this reason. But if foods can last a long time then people can buy larger lots at a time for months in advance. Then if toxins are introduced into the food supply a smaller fraction of the public will eat the contaminated food before the contamination causes symptoms and the cause is identified. For example, someone who buys canned or dried milk would run a much lower risk of getting poisoned by botulinum toxin in milk. Most of the consumers of dried milk on a particular day are consuming milk produced at a variety of times in the past.

    By Randall Parker 2005 July 13 12:08 PM  Dangers Terrorism Food
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    2005 July 12 Tuesday
    Twins Study Shows Some Have Genetically Low Cholesterol

    Some people can eat a lot of fat without much change in cholesterol levels.

    BERKELEY, CA – Why does it seem like some people can eat all the ice cream they want without increasing their cholesterol or gaining much weight, while others with high cholesterol have to watch their diets like a hawk? Because no matter what their lifestyle, people's genes play an overriding role in their cholesterol response.

    So says a new study by researchers at the Department of Energy's Lawrence Berkeley National Laboratory and the Children's Hospital Oakland Research Institute (CHORI), conducted by Paul Williams of Berkeley Lab's Life Sciences Division in collaboration with Robin Rawlings and Patricia Blanche of CHORI and Ronald M. Krauss of CHORI and Berkeley Lab's Genomics Division. They report their findings in the July 8, 2005, issue of the American Journal of Clinical Nutrition.

    The investigators analyzed how "bad" cholesterol (low-density lipoprotein, or LDL, cholesterol) responded to diets that were either high or low in fat in 28 pairs of identical male twins — one twin a vigorous exerciser, the other a comparative couch potato.

    "Although identical twins share exactly the same genes, we chose these twins because they had very different lifestyles," says Williams. "One member of each pair was a regular long-distance runner, someone we contacted through Runner's World magazine or at races around the country. His brother clocked 40 kilometers a week less, at least, if he exercised at all."

    For six weeks the twins ate either a high-fat diet (40 percent of its calories from fat) or a low-fat diet (only 20 percent of its calories from fat); then the pairs switched diets for another six weeks. After each six-week period the twins' blood cholesterol levels were tested.

    The researchers were interested in learning if blood cholesterol changes due to the different diets would be the same or different in each pair of genetically identical twins, even though their lifestyles were very different. A correlation of zero between the two would mean that their responses to the diets had no relation to each other, while a correlation of 1.0 would mean that their responses were identical.

    The researchers found an astounding 0.7 correlation in responses to the change in diet, an incredibly strong similarity in the way each pair of twins responded — even though the responses themselves among different pairs of twins differed considerably.

    "If one of the twins could eat a high-fat diet without increasing his bad cholesterol, then so could his brother," says Williams. "But if one of the twins' LDL cholesterol shot up when they went on the high-fat diet, his brother's did too."

    The correlations showed that the twins had very similar changes in LDL cholesterol because they had the same genes. Some twins had one or more genes that made them very sensitive to the amount of fat in their diets. Other twins had genes that made them insensitive to dietary fat, no matter how much they exercised.

    The genes which cause this difference in response to fats will be identified. A more immediate benefit of identifying those genes would come from genetic tests that would tell you whether your cholesterol level is sensitive to your diet. If your cholesterol level is not sensitive to the amount or types of fat you eat then you could stop fighting your desires to eat higher fat foods - at least for the sake of your cholesterol.

    A longer term benefit will come from using this knowledge to guide the genetic reengineering of one's cholesterol metabolosm. My guess is that these genes exercise their influence in the liver. For people who have diet-sensitive cholesterol gene therapy could reprogram the liver cells to keep overall cholesterol low and HDL cholesterol high regardless of diet or exercise. Either the existing liver could be reprogrammed or stem cells from your body could be removed, genetically modified, and then grown to create a replacement liver that more optimally regulates cholesterol.

    Not everyone who has cholesterol levels that are insensitive to diet have low cholesterol. Some have cholesterol that is stuck at dangerously high levels. Those people who have high cholesterol without much dietary sensitivity for cholesterol levels would derive the greatest benefit from geneticaly reengineered livers. For now the best they can do is take statin drugs.

    If you were willing to make the effort and spend some money you could discover with the help of your doctor whether your cholesterol level is diet sensitive. Try different diets with different fat levels and fat types and get a test of your various types of cholesterol after eating each diet. for 6 weeks as these researchers did. If you want to try this then consider putting the ape diet on your list of diets to try. If even the ape diet doesn't lower cholesterol then you might as well enjoy ice cream for breakfast.

    By Randall Parker 2005 July 12 12:36 PM  Aging Diet Studies
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    2005 July 10 Sunday
    Nanowires Could Be Run Up All Brain Capillaries For Neural Interface

    (same article here and here)

    Neuroscientist Rudolfo Llinas and his colleagues envision an entire array of nanowires being connected to a catheter tube, which could then be guided through the circulatory system to the brain. Once there, the nanowires would spread into a kind of bouquet, branching out into tinier and tinier blood vessels until they reached specific locations. Each nanowire would then be used to record the electrical activity of a single nerve cells, or small groups of nerve cells.

    The nanowires would be very small as compared to the thickness of capillaries.

    Writing in the July 5, 2005, online issue of The Journal of Nanoparticle Research, the researchers explain it is becoming feasible to create nanowires far thinner than even the tiniest capillary vessels. That means nanowires could, in principle, be threaded through the circulatory system to any point in the body without blocking the normal flow of blood or interfering with the exchange of gasses and nutrients through the blood-vessel walls.

    The team describes a proof-of-principle experiment in which they first guided platinum nanowires into the vascular system of tissue samples, and then successfully used the wires to detect the activity of individual neurons lying adjacent to the blood vessels.

    Rodolfo R. Llinás of the New York University School of Medicine led the team, which included Kerry D. Walton, also of the NYU medical school; Masayuki Nakao of the University of Tokyo; and Ian Hunter and Patrick A. Anquetil of the Massachusetts Institute of Technology.

    Nanowires that can receive electrical signals can also be set up to send signals.

    "In this case, we see the first-ever application of nanotechnology to understanding the brain at the neuron-to-neuron interaction level with a non-intrusive, biocompatible and biodegradable nano-probe," said Roco. "With careful attention to ethical issues, it promises entirely new areas of study, and ultimately could lead to new therapies and new ways of treating diseases. This illustrates the new generations of nanoscale active devices and complex nanosystems."

    Likewise, the nanowire technique could greatly improve doctors' ability to pinpoint damage from injury and stroke, localize the cause of seizures, and detect the presence of tumors and other brain abnormalities. Better still, Llinás and his coauthors point out, the nanowires could deliver electrical impulses as well as receive them. So the technique has potential as a treatment for Parkinson's and similar diseases.

    Picture an embedded nanotech computer wired up to feed the mind information as images, sounds, or simply thoughts that suddenly happen. At the extreme the nanowires could be used to take over a person and control them. Picture a "Manchurian Candidate" controlled by a foreign power. Or picture criminals whose nanocomputers monitor their thoughts and send inhibiting messages that prevent violent acts and other forbidden behavior.

    Using embedded nanowire sensors to make sense of complex thoughts in brains will remain hard to do for years to come. But I predict that identification of some basic emotions or urges will be easier to accomplish. Once reactive loops to suppress emotions such as hostility or sexual desire reach technical feasibility consider the issues we'll face. Should rapists or pedophiles up for parole be required to submit to nanowire circuitry implants that suppress their sexual desires? One can even imagine a home surveillance system where the parolee can get their sexual desires unlocked only if they present a willing adult to a video camera hooked up to a police station. A parolee's sexual desires could even get automatically deactivated using a GPS monitoring device that activates as they leave home. Or a home transmitter that unblocks their sexual desire circuits could have a reach of only, say, 50 feet around their house and as they move away they lose the signal that allows their sexual desires to work.

    Repressive regimes could use embedded nanowire circuits to ensure obedience or as interrogation tools to activate a person's memories and force them to talk. On the bright side embedded nanowires could enable viewing of movies or listening without any external device to carry along. One could have an embedded internet link to allow one to think search requests. I'm reminded of the movie The President's Analyst where "The Phone Company" kidnaps James Coburn's character to try to convince him to advise the President of the United States to support embedding electronic phone circuits in everyones' brains. I'm also reminded of the Stargate SG-1 Goauld that take over the brains of humans that they enter into.

    Ramez Naam's book More Than Human has a treatment of Llinas's proposal as well. He covers the wider issue of brain-computer interfaces in his chapter The Wired Brain. Some of what he writes about neurobiology research was news to me when I read it. Another good book to read at the same time is Joel Garreau's book Radical Evolution.

    By Randall Parker 2005 July 10 02:56 PM  Nanotech for Biotech
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    Research Spending In China Places It In Third Place In World

    Spending on R&D in China is rapidly rising.

    Fewer Americans are earning doctoral degrees in science and engineering, 25,509 in 2001 (the last year for which comparative figures are available), versus 27,243 in 1996. And American governmental spending on R&D in the physical sciences, math and engineering has slipped from 0.25 percent of the gross domestic product (GDP) in 1970 to 0.16 percent in 2003, according to the Alliance for Science & Technology Research in America (ASTRA). Meanwhile, China is steaming in the opposite direction. China nearly doubled its output of science and engineering Ph.D.s between 1996 and 2001, to 8,153. And in the six years between 1997 and 2002, national and local governmental spending on research in China doubled, to approximately $9.9 billion. On top of that, multinational corporations have been racing to set up research centers in the country and China's own industrial titans are now plunging into R&D, realizing they have to have their own technology to compete in global markets.

    Combined private and public spending on R&D in China as a percentage of GDP has grown from 0.6 percent in 1996 to 1.29 percent in 2002. This is still far below the roughly 2.7 percent of GDP spent in the U.S. But it still positions China as the world's third-largest investor in R&D, after the U.S. and Japan, when measured in purchasing-power parity dollars, according to the U.S. National Science Foundation.

    Chinese universities are producing as many scientists and engineers as American universities.

    A large part of China's growing success rests on a burgeoning and well-trained scientific workforce. The country produced 337,000 science and engineering graduates with bachelor's degrees in 2001, a figure that approaches the 398,000 produced in the U.S. Given that reliable statistics are several years old, it's possible that China is already producing more science and engineering bachelor's graduates than the U.S.

    China's population is about four and a half times larger than the United States. The Chinese score above the US average on IQ tests. At the same time demographic trends in the United States show that the US is not going to be able to compete by building a smarter population. If the United States shifted its immigration policy totally toward brain draining the rest of the world and if it ended all immigration below some IQ threshold (say 125 or 130 perhaps) then the US might be able to retain its lead in brain work. But US policy makers are living in a fantasy land where demographics do not matter and US educational problems can be fixed with more money. It is a nice fantasy. But unfortunately reality bears little relation to that fantasy. Until policy makers and intellectuals admit that genetic differences cause most large IQ differences immigration policy will work against national science and technology strategy.

    The big wild card down the line in two or three decades time is offspring genetic engineering. Will China or the United States more rapidly embrace genetic engineering for IQ enhancement? The Chinese, being more pragmatic and less religious, might be expected to embrace IQ enhancement more quickly. However, a high IQ population will pose a serious threat to the stability of China's non-democratic government. The leaders might decide that an IQ-boosted population will become impossible to rule autocratically and hence the leaders might block offspring genetic engineering. Or then again, they might embrace the technology and systematically require offspring genetic engineering for cognitive enhancement. Any guesses? I don't know the answer on this one.

    By Randall Parker 2005 July 10 01:40 PM  Policy Science
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    2005 July 07 Thursday
    Corn Ethanol And Biodiesel Net Energy Losers

    David Pimentel and Tad W. Patzek have once again analyzed plants as ethanol energy sources and found the energy cost of growth and processing outweighs the energy produced.

    ITHACA, N.Y. -- Turning plants such as corn, soybeans and sunflowers into fuel uses much more energy than the resulting ethanol or biodiesel generates, according to a new Cornell University and University of California-Berkeley study.

    "There is just no energy benefit to using plant biomass for liquid fuel," says David Pimentel, professor of ecology and agriculture at Cornell. "These strategies are not sustainable."

    Pimentel and Tad W. Patzek, professor of civil and environmental engineering at Berkeley, conducted a detailed analysis of the energy input-yield ratios of producing ethanol from corn, switch grass and wood biomass as well as for producing biodiesel from soybean and sunflower plants. Their report is published in Natural Resources Research (Vol. 14:1, 65-76).

    In terms of energy output compared with energy input for ethanol production, the study found that:

    • corn requires 29 percent more fossil energy than the fuel produced;
    • switch grass requires 45 percent more fossil energy than the fuel produced; and
    • wood biomass requires 57 percent more fossil energy than the fuel produced.

    In terms of energy output compared with the energy input for biodiesel production, the study found that:

    • soybean plants requires 27 percent more fossil energy than the fuel produced, and
    • sunflower plants requires 118 percent more fossil energy than the fuel produced.

    In assessing inputs, the researchers considered such factors as the energy used in producing the crop (including production of pesticides and fertilizer, running farm machinery and irrigating, grinding and transporting the crop) and in fermenting/distilling the ethanol from the water mix. Although additional costs are incurred, such as federal and state subsidies that are passed on to consumers and the costs associated with environmental pollution or degradation, these figures were not included in the analysis.

    Another group of researchers found sugarcane ethanol in Brazil to be a net producer of usable energy whereas corn ethanol in the United States provided only a small net benefit.

    A new study of the carbon dioxide emissions, cropland area requirements, and other environmental consequences of growing corn and sugarcane to produce fuel ethanol indicates that the "direct and indirect environmental impacts of growing, harvesting, and converting biomass to ethanol far exceed any value in developing this energy resource on a large scale." The study, published in the July 2005 issue of BioScience, the journal of the American Institute of Biological Sciences (AIBS), uses the “ecological footprint” concept to assess needs for ethanol production from sugarcane, now widespread in Brazil, and from corn, which is increasing in the United States.

    In Brazil, ethanol from fermentation of sugarcane is used pure or blended with gasoline to yield gasohol, which contains 24 percent ethanol. In the United States, ethanol made from corn, production of which is heavily subsidized, is used in an 85 percent ethanol mixture called E85. In 2003, ethanol-blended gasoline accounted for more than 10 percent of gasoline sales in the United States.

    The authors of the study assessed the energy required to produce the crops and to manufacture and distribute the resulting fuels. In the United States, ethanol yielded only about 10 percent more energy than was required to produce it; in Brazil, where a different process is used, ethanol yielded 3.7 times more energy than was used to produce it. The researchers, Marcelo E. Dias de Oliveira, Burton E. Vaughan, and Edward J. Rykiel, Jr., also weighed effects of fuel ethanol use on carbon dioxide emissions, soil erosion, loss of biodiversity, and water and air pollution, assuming vehicles representative of each country. Specialized software was used to analyze the sensitivity of the conclusions to diverse assumptions in the analysis.

    Dias de Oliveira and colleagues then looked at some consequences of moving to greater fuel ethanol use. The results were unfavorable to fuel ethanol in either country. In Brazil, reducing the rate of deforestation seemed likely to be more effective for taking carbon dioxide out of the atmosphere. In the United States, reliance on ethanol to fuel the automobile fleet would require enormous, unachievable areas of corn agriculture, and the environmental impacts would outweigh its benefits. "Ethanol cannot alleviate the United States’ dependence on petroleum," Dias de Oliveira and colleagues conclude. They argue for the development of multiple alternatives to fossil fuels. Ethanol may, however, still be useful in regions or cities with critical pollution problems, they write, and to make use of agricultural wastes.

    My guess is that Pimental and Patzek have more accurate results because they have accounted for more factors. They've repeatedly published on this topic and have refined their model. So they are probably closer to the truth at this point. However, this is just a guess on my part.

    I continue to be skeptical of biomass as a major source of energy to replace oil. While crops grown for biomass purposes may not measure up it is possible that waste biomass from sewage, residential green waste, and other sources might eventually become usable as sources of net energy.

    The future development of more energy efficient means for converting biomass materials into liquid hydrocarbons combined with advances in agricultural technologies might eventually make crops net energy producers. But increased demand for crop land, water, and pesticides for energy producing crops will bring environmental costs. We'd be better off advancing technologies for nuclear, solar photovoltaics, and batteries so that we can reduce our use of liquid fuels for transportation.

    By Randall Parker 2005 July 07 06:04 PM  Energy Biomass
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    2005 July 06 Wednesday
    Ovulating Women Prefer Smell Of Dominant Men

    Natural selection has produced human females who prefer to mate with dominant men when the females are most fertile.

    A group of 65 women then smelled the pads and rated the sexiness and masculinity of the scent. Women in the middle week of their menstrual cycle, the point at which fertility is at its peak, tended to prefer the smell of the men who scored highest on the dominance quiz. This preference was not shown by women at other points in their cycle. What's more, the effect was only significant for women in long-term relationships, the researchers report in the journal Biology Letters1. This shows that both menstrual phase and relationship status can have an effect on which men women tend to prefer, says Havlícek.

    What other differences are there in men who score high in dominance? I'd love to see hormone levels in men who score higher in dominance characteristics versus men who score lower. Keep in mind that testosterone levels drop in married men and drop even further in married men with children. Are men who "smell dominant" more likely to be single? Or are they more likely to have jobs that put them in positions of responsibility and power over others? Do they have higher average incomes than men who smell less desirable? Or is that dominant smell always there in some men due to genetic reasons regardless of their station in life?

    Whatever characteristics make a man dominant also makes him smell like better genetic material.

    Researcher Dr Craig Roberts told the BBC News website: "There seems to be some sort of physiological mechanism that directs women to indicators of good genes.

    "The offspring of such a coupling would therefore be likely to have better genes."

    Some women use their long term mates for child raising while preferring other men as sperm donors.

    "A strong association between male odour-sexiness and psychological dominance was only found for non-single women in the fertile phase of their menstrual cycle."

    They added: "A mixed-mating strategy may have evolved in females - they prefer genetically superior males for short-term or extra-pair sexual partners while, at the same time, they seek males who are more willing to invest in their offspring as long-term or social partners."

    Could that dominant smell be put in a perfume bottle? Perhaps. Or is dominance more detectable by the absence of some other smell? Say, whatever smells comes out when you feel fear?

    One problem I see coming up when offspring genetic engineering becomes possible is that people may make all their male offspring so dominant that we end up with a society where men can't cooperate very well because no one wants to take orders. Oh, and fights and murders might become more frequent as well. Hey, technology creates problems. I'm not a utopian about the future.

    By Randall Parker 2005 July 06 09:23 PM  Brain Sexuality
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    2005 July 05 Tuesday
    Aubrey de Grey: Stop Feeling Ashamed Of Goal Of Rejuvenation

    Writing in the European Molecular Biology Organisation's journal EMBO Reports Cambridge UK biogerontologist Aubrey de Grey makes the case for pursuing complete human rejuvenation as an achievable and desirable goal in an article entitled "Resistance to debate on how to postpone ageing is delaying progress and costing lives".

    Before moving on to discuss the second, widely overlooked, source of political resistance to funding ageing research, we can already note how the traditional gerontological rhetoric has become an albatross—and perhaps always was. "Ageing is not a disease", as I noted earlier, has long been a slogan of gerontology. Politicians may be inclined to feel that, well, if ageing is not a disease, it is probably not something we ought to be spending much effort combating, then, is it? When we reflect that this is a gut feeling that most people, and thus most politicians, probably have at the outset—what Miller (2002) termed "gerontologiphobia"—and also that when money is tight its allocators seek excuses to narrow the list of candidate recipients, we see clearly that describing ageing as "not a disease" has severe rhetorical drawbacks, regardless of the value it may once have had in distinguishing biogerontology from other biomedical research.

    This problem is in my view dwarfed, however, by the second difficulty that politicians may have in embracing biogerontologists' arguments: the merit of spending money in pursuit of a given goal depends not only on that goal's desirability but also on its feasibility. Those of us who do not suffer from gerontologiphobia are persistently awed by the logical contortions that gerontologiphobes perform when asked to justify their pro-ageing stance. Similar awe—although that might not be the word they would use—may be felt by politicians who encounter the efforts of gerontologists to extract from available data an argument that their work will probably cause substantial compression of morbidity in the foreseeable future.

    Although the concept is much older, the term 'compression of morbidity' was introduced by James Fries in a paper published in 1980: "Present data allow calculation of the ideal average life span, approximately 85 years. Chronic illness may presumably be postponed by changes in life style [...] Thus, the average age at first infirmity can be raised, thereby making the morbidity curve more rectangular. Extension of adult vigor far into a fixed life span compresses the period of senescence near the end of life" (Fries, 1980). Even ignoring the questionable assumption of a fixed lifespan, we immediately see that Fries is not predicting that combating ageing will compress morbidity. Instead, he stresses "changes in life style"—not a noted sphere of biogerontological influence. Fries's hope that US morbidity would be compressed has been realized in the meantime, and the details of that change duly support the theory that lifestyle, rather than biomedical progress, is responsible. All the compression observed is in mild to moderate disability, which is substantially achievable by lifestyle changes, whereas absolutely no compression of severe morbidity has occurred (Fries, 2003).

    Aubrey thinks many biogerontologists entered the field when there was little hope of ever stopping or reversing aging. Therefore most entered to satisfy their curiosity rather than to achieve goals which have practical uses.

    I suspect that, in their heart of hearts, many of my colleagues in biogerontology secretly realize or at least fear the futility of compressing morbidity by manipulating ageing. These people face an unenviable problem: they are scientists trapped in a biomedical discipline, so their path of least resistance may be to submit to the gerontologiphobia of society and not rock the boat. I should explain what I mean by this. When many of today's senior biogerontologists entered the field, serious postponement of ageing was not realistic, and they therefore became biogerontologists partly—and in most cases, I believe, mainly—with the curiosity-driven motivations of a basic scientist rather than the goal-directed ones of an engineer or clinician. They find discovery fulfilling, and seek only the resources to carry on discovering more. Any talk of actually doing something about ageing is then a Fig leaf—the sort of camouflage that all scientists use to make society value their work without fretting that there is no guarantee that it will ever be useful. Perhaps this is why those who propound the most blatantly invalid reasons why our hitherto minimal rate of progress in postponing ageing cannot be accelerated—reasons transparently based on misuse of logic (Hayflick, 2004) or of extrapolation (Olshansky et al, 2001)—are often allowed to carry on espousing their views without challenge. There may be a tacit hope that the blinding unjustifiability of their pessimism will distract the attention of the funding bodies from the subtler contradictions in what mainstream gerontology is saying to justify its existence.

    But we no longer live in that era when rejuvenation was absolutely out of the question. Biotechnology has come so far that genomes can be sequenced at increasingly faster speeds and for declining costs. Technologies developed for the semiconductor industry are being adapted to make microfluidic devices which allow increasingly precise and cheap manipulation of biological systems down at the scale of cells and molecules. Computers allow automation and scaling of processes which required enormous quantities of manual labor in past decades.

    The accumulation of tools for biological science and biotechnology is enabling more ambitious undertakings. Many scientists are already attempting to develop treatments that effectively reverse some processes of aging. Scientists working today will find ways to, for example, grow replacement organs and to send stem cells into the body to do repairs. Freshly grown replacement organs and other freshly grown body parts will entirely reverse the age of whatever parts of the body they replace. Immunotherapies to remove extracellular junk have been tested in animals and humans and continue to be developed.

    Today scientists are working on parts of the rejuvenation puzzle. Most do so in order to treat specific diseases which are the result of aging (e.g. heart disease, kidney failure) rather than as part of a systematic attempt to roll back all of the causes of aging. Their work is still very valuable. But the lack of widespread embrace of the larger goal of full rejuvenation inevitably means that little effort goes into some of the therapies needed for full rejuvenation. Unless the goal of full rejuvenation becomes the goal of biogerontology the gaps in the current efforts will go unaddressed for years to come.

    Aubrey argues that the many different diseases associated with aging could be more effectively treated by rejuvenating the body rather than attack each disease. This idea can be grasped by looking at just a single organ, the liver for example. The liver can fail due to many reasons (e.g. a variety of pathogens, alcohol, trauma from an accident, genetic defects, environmental toxins, cancer, and still other diseases). Treatments can be developed for each disease and many labs are working on all these causes of liver failure. But a replacement liver will fix just about all of them. Even if the pathogens that cause liver damage can not be removed when a liver is replaced the pathogens take decades to destroy the liver. So a replacement liver would buy additional decades of life during which to find a cure for the pathogens. For cancer discovered at an early stage before metastasis a replacement liver would even effectively cure liver cancer.

    Aubrey says we should not feel ashamed to declare the defeat of aging as a worthy and achievable goal.

    Just as the purpose of oncology is to defeat cancer, the purpose of biogerontology is, and should be declared to be, to defeat ageing. Vintage cars do not age, because their owners have the dedication and expertise to give them the necessary maintenance. We will in due course have the expertise to maintain ourselves with similar fidelity, and few can doubt that we will then also have the dedication. Hastening that advance, therefore, is a legitimate and honourable goal of which we have been ashamed for too long.

    I agree. The desire to live is not dishonorable. The desire for youthfulness is not decadent. We should pursue the goal of full rejuvenation and defeat all human diseases in the process.

    Also see Reason's coverage of Aubrey's article.

    By Randall Parker 2005 July 05 10:41 AM  Aging Debate
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    2005 July 01 Friday
    Iron And Cholesterol Increase Cancer Risk

    Dr. Arch G. Mainous, III and colleagues at the Medical University of South Carolina in Charleston have found that having a combination of either high VLDL cholesterol or low HDL cholesterol with high iron in the blood raises cancer risk by a factor of 2.68 and 2.82 respectively.

    Iron and lipids combine to create oxidative stress, and oxidative stress has a role in the development of cancer. The objective was to determine the risk of cancer among persons who had both elevated iron and lipids. The authors conducted an analysis of the cohort available in the Framingham Offspring Study. Adults aged 30 or more years at baseline had serum iron and high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol, and very low density lipoprotein cholesterol (VLDL-C) assessed in 1979–1982 and were followed for development of cancer until 1996–1997 (n = 3,278). Cox regression models were computed while controlling for age, gender, smoking status, and body mass index. In adjusted models, both elevated iron (hazard ratio (HR) = 1.66, 95% confidence interval (CI): 1.11, 2.46; 29 cases) and VLDL-C (HR = 1.54, 95% CI: 1.04, 2.28; 93 cases) had significant independent risks for development of cancer. When elevated iron was combined with elevated VLDL-C, the adjusted relative risk of cancer increased (HR = 2.68, 95% CI: 1.49, 4.83; 18 cases). Elevated iron and low HDL-C also had a significant adjusted relative risk of cancer (HR = 2.82, 95% CI: 1.50, 5.28; 14 cases). The results suggest that elevated serum iron levels coupled with either high VLDL-C or low HDL-C appear to interact to increase cancer risk in this cohort.

    Those are huge increases in risk, almost tripling the best case risk. The high iron is probably generating free radicals that are oxidizing the LDL and VLDL cholesterol. Perhaps the HDL cholesterol removes or neutralizes the reactive forms of LDL and VLDL and hence lower HDL raises the risks.

    Exercise will raise HDL cholesterol. What will lower VLDL cholesterol? Same factors that lower LDL cholesterol? Then there is iron. Are the high iron people in this study that way due to genetic factors? In other words, what can be done to lower cancer risk due to cholesterol and iron interactions? Keep in mind as well, the oxidative stress that produces the higher cancer risk also probably accelerates general aging. So anything that reduces cancer risk from cholesterol and iron probably slows down aging in general.

    By Randall Parker 2005 July 01 10:07 PM  Aging Diet Studies
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    Reflector Satellites Proposed To Prevent Global Warming

    James Pearson, John Oldson and Eugene Levin of Star Technology and Research in Mount Pleasant South Carolina propose construction of a system of satellites to control the amount of sunlight that reaches and warms Earth.

    A wild idea to combat global warming suggests creating an artificial ring of small particles or spacecrafts around Earth to shade the tropics and moderate climate extremes.

    There would be side effects, proponents admit. An effective sunlight-scattering particle ring would illuminate our night sky as much as the full Moon, for example.

    And the price tag would knock the socks off even a big-budget agency like NASA: $6 trillion to $200 trillion for the particle approach. Deploying tiny spacecraft would come at a relative bargain: a mere $500 billion tops.

    But the idea, detailed today in the online version of the journal Acta Astronautica, illustrates that climate change can be battled with new technologies, according to one scientist not involved in the new work.

    Social anthropologist Benny Peiser of the British Liverpool John Moores University says this proposal demonstrates humans can prevent disastrous climate changes.

    "I don't think that the modest warming trend we are currently experiencing poses any significant or long-term threat," Peiser told LiveScience. "Nevertheless, what the paper does show quite impressively is that our hyper-complex civilization is theoretically and technologically capable of dealing with any significant climate change we may potentially face in the future."

    Here is the abstract to the research paper. The particle solution is too expensive but the ring of controlled satellites could be implemented for at most a half trillion US dollars.

    An artificial planetary ring about the Earth, composed of passive particles or controlled spacecraft with parasols, is proposed to reduce global warming. A flat ring from 1.2 to 1.6 Earth radii would shade mainly the tropics, moderating climate extremes, and counteract global warming. A preliminary design of the ring is developed, and a one-dimensional climate model is used to evaluate its performance. Earth, lunar, and asteroidal material sources are compared to determine the costs of the particle ring and the spacecraft ring. Environmental concerns and effects on existing satellites in Earth orbit are addressed. The particle ring endangers LEO satellites, is limited to cooling only, and lights the night many times as bright as the full moon. It would cost an estimated $6–200 trillion. The ring of controlled satellites with reflectors has other attractive uses, and would cost an estimated $125–500 billion.

    Satellites with reflectors could rotate to present more or less reflective surfaces toward the Sun. Also, a fancier design to such satellites could allow them to also function as communications or remote sensing satellites. One could even imagine adjusting the orientation of some of the satellites to reflect more light onto crops to make them grow more rapidly.

    Whether global warming ever becomes a big enough problem to justify a climate engineering project remains to be seen. Many would see such a project as an intervention in nature that humans have no right to make. Some would claim that climate engineering amounts to "playing God". Also, such a project would inevitably change climate in some parts of the world in ways that residents of those parts would see as detrimental. However, should humans ever colonize Mars I expect proposals for climate engineering of Mars to meet far less resistance on ideological or consequential grounds. Mars is so inhospitable to human habitation that the debate would center around what is the best way to adjust Mars to human needs. There'd be no fear of making some parts of Mars worse for humans in order to make other parts better. Also, nature as we understand it with a large range species does not exist on Mars. So the threat to Martian lifeforms (if any still exist) would be small as compared how climate engineering on Earth would inevitably shrink some ecological niches while expanding others.

    I am not a pessimist about global warming for the simple reason that humans are going to become orders of magnitude more technologically capable in the 21st century. All problems will become more solvable. I think it unlikely humans will have much need for fossil fuels 50 years from now. Other energy technologies will become more attractive long before significant global warming takes place.

    By Randall Parker 2005 July 01 01:30 PM  Climate Engineering
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