Erosion caught in arial photograph.

I just saw this and it struck me how scary and real erosion is. Can you imagine what the lives of these farmers will be like in a few years’ time? What will they leave their kids?

Be sure to read the photo’s comments.

Technorati Tags: erosion, Grady, New Mexico, USA

Faith and the cardiovascular system

Results presented at the American Society of Hypertension indicate that religious people have lower blood pressure. By studying over 5000 African Americans, the largest study of its kind, they found that female gender, lower socioeconomic status, increasing age, and lower levels of cortisol were associated with more religious activities. Those with more religious activities and participation had significantly lower diastolic blood pressure, and significantly lower systolic blood pressure. High levels of cortisol, it should be noted, are a marker for stress.

These results support earlier studies, so they are not particularly surprising. What I found interesting is their confirmation of anecdotal observations that older people and women tend to be more religious. I wonder why that is so.

This also complements another recent study, where people were prayed for by strangers; that is the people themselves did not pray. In that study, researchers looked at effect of prayer on cardiac bypass patients, and found that prayers by strangers did not have any positive effects. That report contradicts some other reports, and so this question is not yet 100% settled. However, as best as we can tell, prayer by strangers does not help.

So what does this all mean? Being religious yourself may help relax and be more healthy. That may not be surprising given that paryer is all about relaxation. As for prayers from others, well it’s almost certain they don’t help. As always in science, we need more research to figure this one out.

Technorati Tags: faith, religion, blood pressure, cortisol, spirituality, spiritual experiences, heart, cardiovascular disease, stress, depression, cardiac bypass, medicine, science

Speciation of humans and chimps, and evolution.

One of the most important concepts in evolution is about speciation, that is, how new species evolve. There are many ways for species to evolve, but they all boil down to one idea: reproductive isolation. Simply put, two different species cannot mate with each other, or if they somehow manage to do it, the offspring is sterile. Examples: human and chimps, the plants, etc, are all reproductively isolated; one example of species reproduce to give sterile offspring are donkeys and horses producing sterile mules.

So quick recap: evolution of new species occurs when there is reproductive isolation. Now the news…

How did the human species evolve? The traditional answer to that question is somewhere around 4.6-6 million years ago. Then, it is thought, the line that lead to humans split from the line that lead to chimpanzees from the human-chimp common ancestor. However, this was causing a bit of a problem as new fossil evidence came up, and the date was pushed back to 7 million years ago. Another way is to measure all the genetic differences between humans and chimps (or any closely-related species), and then assume a certain rate of mutation (genetic changes). Knowing the mutation rate and the number of genetic differences allows us to calculate when the two species split. However, this has its own problems as you get different answers depending on which mutations you study and what mutation rate you assume.

This week, scientists reported on a new, much more accurate, technique to measure speciation. The technique checked 20 million mutations (wow!) and measure the rate each one evolved separately. The final answer they come up with is that humans and chimps split multiple times, at one point forming a hybrid. The first split first occured more recently than we originally thought, most probably around 5.4 million years ago, and the split happened over a longer time-frame. They also report an interesting and unexpected finding, but it explains the new data.

When they looked at mutations in the X-chromosome, the DNA part of our genome that determines gender (sex), they found that human and chimp X-chromosomes are the most related chromosomes in the two species. They estimate that the X-chromosomes finally split only 1.2 million years ago. Since the X-chromosome helps determine sex and reproductive isolation, this may be why humans and chimps retained the ability to mate and form hybrids for such a long time.

So what does all this mean? Well, many things:

• We now have more evidence that humans and chimps are closely related. This adds to the debate about human evolution.
• We now have a ‘road map’ for how humans evolved. This will allow us to better place the fossil evidence, and to also figure out the stages properly. We have fossil evidence dating back to the hybrid stage, and even before the human-chimp split. The bones can now be ordered more accurately for us to see just how humans evolved.
• This is by far the most complex speciation example we have found. That doesn’t mean it hasn’t happened elsewhere; we simply haven’t been looking for it! Now that we have a technique to better study speciation, who knows what we will uncover.

If you want, the Discovery Channel and the NY Times have commentaries too.

Technorati Tags: humans, chimpanzees, chimps, evolution, speciation, X-chromosome, reproductive isolation, human evolution, fossils, fossil record, science

SPOT-NOSED smell technology yields electronic nose.

A new approach for an ‘electronic nose’ has been developed by researchers in Spain, France and Italy; the project is called SPOT-NOSED.

This ‘biosensor’ (an electronic sensor based on biological detection) is unusual in how it’s made. The researchers used actual proteins used in rat noses, and used them to detect smells in an electronic device. How cool is that?

By placing a layer of proteins that constitute the olfactory receptors (the proteins used to detect scents) in animal noses, a system capable of detecting odorants at concentrations that would be imperceptible to humans is made.

Where do these proteins come from? Several hundred different proteins were genetically copied from rats and grown in yeast. Nanotechnology makes such an electronic nose feasible, even though the human nose uses 1,000 different proteins to allow the brain to recognise 10,000 different smells.

The next step is to recognize scents: it’s exciting to be able to create this detector, but it’s not of any use. Luckily, the project partners are now planning to continue their research and develop the instrumentation and software tools necessary for an electronic nose to recognise smells. This mimics the brain in animals.

As the coordinator of the SPOT-NOSED project, Josep Samitier notes, "The potential uses of smell technology are endless."

Technorati Tags: SPOT-NOSED, biosensor, olfactory, Spain, France, Italy, biotechnology, smell, scent, science, technology

Running mice give evidence about skin cancer, colorectal cancer

Two papers published this week in the journal Carcinogenesis talk about the inhibitory effects on cancer of voluntary exercise in mice.

In the first paper, researchers looked at inhibition of skin cancer induced by ultraviolet light (UVB). Using a special mouse line under two different cancer-inducing conditions, they sum up their results with:

…voluntary running wheel exercise delayed the appearance of tumors, decreased the number of tumors per mouse and decreased tumor volume per mouse.

The effects described here indicate that voluntary running wheel exercise inhibits UVB-induced skin tumorigenesis and may also inhibit tumor growth.

The mouse line used is a model for skin cancer in humans: it has a mutation in a gene linked to skin cancer, meaning that these mice are very susceptible to UV-induced skin cancer. The two conditions used were:

• ‘High risk’, meaning the UV dose given was enough to give the mice at a very high chance of getting skin cancer.
• ‘Complete’, which is the same UV dose as the ‘high risk group’, but given for a longer time. This virtually guarantees incidence of cancer in these mice.

The beneficial effects of exercise was found in both groups. How applicable this finding is to humans remains to be seen, though, but it’s a good sign.

The second paper showed that voluntary exercise and a restricted diet reduced the number and size of pre-cancerous polyps in the intestines of male mice and improved survival. The study is the first to suggest that a "negative energy balance" appeared to be the important factor in inhibiting the growth of polyps, which are the forerunners of colorectal tumors. A negative energy balance is produced by increasing the mice’s energy output by use of a running wheel, while maintaining a restricted calorie intake; that is: mice ate less food than they would have needed to offset the increase in exercise.

Lead researcher Lisa Colbert summed it up for us:

"The exercising mice ran an average of 3.8 km a day, and the further they ran the fewer polyps they had. Exercise significantly reduced total polyp number and polyp size, as well as prolonging survival. On average, there were 16 polyps per mouse in the exercising mice compared to 22 polyps in the control mice - a decrease of 25 percent."

Again, studies looking at humans are necessary before making any medical claims, but this is another excellent lead.

Technorati Tags: exercise, cancer, skin cancer, colorectal cancer, UV, science, medicine

Clean, environmentally friendly, renewable fuel.

There has been a little buzz lately about using ethanol as an oil replacement. The story goes like this: the world’s oil supplies are going to run out sooner or later, so why not find an alternative? Well there have always been alternatives, including solar power, ocean-wave electricity generators, and ethanol.

Ethanol is the sustenance of the drinking class - yes, it’s alcohol. Because it’s so energy rich (that beer belly doesn’t come from nothing, you know ), it makes a great alternative for oil. Actually, we don’t use ethanol as a direct replacement, but it is mixed with unleaded gasoline: 85% ethanol and 15% gasoline. This mixture is a clean, environmentally friendly, fuel; it’s called E85. E85 is a high octane, high performance fuel, and because we can grow (as in plants) ethanol sources, it’s also renewable. Does it get better than that?

The champion of ethanol as a fuel is Brazil. In Brazil, they grow sugar cane and produce huge amounts of sugar. This sugar is then fermented to ethanol, and used as a fuel. The effects on oil consumption and the environment in Brazil are well documented.

To use E85 in your car, it needs to be of a special type, called “flex fuel” or flexible fuel vehicle (FFV). This means that the engine can handle it.

Read a bit more about E85 as an oil alternative.

Technorati Tags: ethanol, alcohol, E85, Brazil, flex fuel, FFV, environment, oil, energy, cars, science

British Ministry of Defence studies UFO sightings.

The BBC reports on a recently de-classified report from the British Ministry of Defence about UFOs. As the BBC quotes:

No evidence exists to suggest that the phenomena seen are hostile or under any type of control, other than that of natural physical forces… There is no evidence that ’solid’ objects exist which could cause a collision hazard.

Ah, scientific analysis of the available evidence. I doubt that’s enough to convince some people…

Technorati Tags: UFOs, UFO, alien, aliens, Britain, BBC, science

Plastic and reconstructive surgery satisfaction survey.

Liposuction was the most commonly done cosmetic surgery procedure done in 2005. A new study looking at patient satisfaction with liposuction has been published. The results show 80% of patients were satisfied with their results and 86% would recommend the procedure to family or friends. 53% thought that their appearance was either "excellent" or "very good", and 33% of patients reported exercising more after the procedure.

Summing up the results, study co-author Jeffrey Kenkel, MD, said:

"Liposuction is one of the most satisfying procedures for patients and most effective at eliminating localized fat. The majority of patients recognize their role in maintaining positive results and pursue a healthy diet and exercise. These patients typically maintain or lose weight after surgery, while those that do not may gain small amounts of weight. Ultimately, one’s lifestyle can affect long term-results."

Technorati Tags: liposuction, health, plastic surgery, cosmetic surgery, diet, exercise, medicine, science

Naturally-found mutants lack primary allergen.

American researchers screening 100 lines of soybeans per day for nine months (!!!) identified two soybean lines that lack the primary allergy-causing soybean protein, called P34. The two lines are virtually identical, and contain mutations that stop the production of P34.

The nice thing about these two soybean lines is that they occurred naturally, and so there are no artificial genetic modification to worry about. This is important for social acceptance of these lines and also for governmental approval. The lines were from the more than 16,000 soybean lines kept in the USDA’s National Soybean Germplasm Collection, and were screened by crop scientists at the University of Illinois at Urbana-Champaign and the USDA-Agricultural Research Service’s Donald Danforth Plant Science Center in St. Louis.

Avoiding soy products is becoming more difficult because of soy’s use as fillers and components of many menu items. While people can read labels before preparing meals at home, avoiding soy at restaurants isn’t as easy. Currently, 6 percent to 8 percent of children are allergic to soy-based products, including infant formulas, while 2 percent of adults have had allergic reactions.

Technorati Tags: allergy, allergen, soybeans, soy, crops, science

Ozone, Antarctica, and humans

First there was the record levels of CO₂ recorded in March, followed by the publication of unexpected warming in Antarctica.

That’s not enough bad news. Nope. Today, we find out that humans definitely have a negative impact on the environment and that the ozone layer is unlikely to recover fully.

Let’s start with the climate report. From the BBC:

The report, from the federal Climate Change Science Program, said trends seen over the last 50 years "cannot be explained by natural processes alone".

The report is actually breaking new ground, because it analyzes old data and finds new evidence for global warming. It also unequivocally links climate change to human activities.

Next up is the fact that the ozone layer might not recover fully. From the paper’s abstract:

Although recent data suggest that total column ozone abundances have at least not decreased over the past eight years for most of the world, it is still uncertain whether this improvement is actually attributable to the observed decline in the amount of ozone-depleting substances in the Earth’s atmosphere.

To rephrase that: the ‘improvement’ we are currently observing in the ozone layer is that it is not depleting further. That is, it is not getting worse, but staying at the same levels. The big caveat, though, is that we are not sure why it’s staying constant: is it due to the world-wide decline in using CFCs and other ozone-depleting chemicals or something else? We need more research for that.

So what do we have? More bad news regarding our environment, and all due to our actions. Will we ever learn? I wonder…

Technorati Tags: gobal warming, greenhouse gases, climate, climate change, ozone, CFCs, environment, science