Science-- there's something for everyone

Saturday, December 31, 2011

140 new species in 2011

Over the past year, researchers at the California Academy of Sciences added 140 new species to the Earthly index.  This effort took the scientists deep into the oceans and to every continent except Antarctica. 

Although the species were spread through many phyla, there were some clusters.  Just over half the new species were arthropods, and 43 of those were ants.  There were 14 vertebrates, all but one of which were fish, the fourteenth being a tortoise.  There were also 11 plants.  You can peruse the entire list here.

























Spanning six continents and three oceans, new discoveries add to the family tree of life on Earth.
Credit: Image courtesy of California Academy of Sciences.

The results of this survey have been published in 33 different papers.  Aside from adding to our knowledge about our fellow inhabitants on this planet, the data helps conservators plan how best to protect critical areas. 

Friday, December 30, 2011

Meet the Kepler space telescope


I’ve mentioned the Kepler space telescope (pictured left) in lots of posts, so I thought it was high time we got a closer look at it.

Kepler is the name of both the telescope and the mission that uses it.  Named after the 17th century astronomer Johannes Kepler, the Kepler telescope was launched in March of 2009 with the goal of finding Earth-like planets. 

Kepler finds planets via the ‘transit method’.  If, from our vantage point, a planet passes in front of its star, we’ll see a compensatory dimming in the light from that star.   Because several of these transits are required to confirm the presence of a planet, it can take years to verify each finding.  As a comparison, an alien civilization looking in our direction would wait four years to see as many transits of the Earth across the Sun.

The Kepler telescope is not rotated to view different aspects of the sky.  Instead, it monitors a single patch of sky, continuously observing the same 100,000 plus stars.  How successful is this strategy?  As of the beginning of this month, the Kepler mission has found over two thousand candidate planets and confirmed thirty-three of them.  You can see a list of these planets along with their properties here.

Where exactly is the Kepler space telescope?  Orbiting the sun, as you can see from the following animation.  Note, objects in this video are not to scale.


In reality, the Kepler telescope is about 3 meters by 5 metersIn contrast, the Hubble Space Telescope, launched in 1990, orbits the Earth rather than the sun and is about 13 meters by 4 meters. 

Thursday, December 29, 2011

Calendar reform


Here’s a problem you didn’t know needed fixing:  our calendar differs from year to year. Steve Hanke and Richard Henry of Johns Hopkins would like to change that.  They propose a new calendar, called the ‘Hanke-Henry Permanent Calendar’ that would be identical from year to year.  Your birthday would fall on the same day of the week from now on, so better hope it’s a weekend.

You can see what 2012 would look like using both the old and the new calendar hereAll the months would have either 30 or 31 days, and there would be an extra week every five or six years to compensate for the fact that the Earth takes 365 and 1/4 days to circle the sun.

Not only would Hanke and Henry simplify the calendar, but they would do away with time zones as well.  Under their system, every place on Earth would be set to Greenwich Mean Time.  It would be noon for everyone on Earth at the same time.  Of course, for some people, that would be in the middle of the night.

Hanke and Henry make the case that these changes would be an asset in our global economy, greatly simplifying international business transactions. The researchers are confident that they can convince people to adopt this new system.  They recommend that people begin using it on a voluntary basis this January 1st, and have set a date for universal adoption at the start of 2017.  I’m sure they will have no trouble convincing shop owners in California to open their doors at 1 am, especially if it's called 9 am.  

Wednesday, December 28, 2011

Just for fun: Olympus Bioscapes 2011



For the past eight years, Olympus America has sponsored the Bioscapes Competition for the most beautiful and/or extraordinary microscopic images. The winning photographs must "depict subjects that are, or at one time were, living".


Here's the 2011 Grand prize winner, by Charles Krebs of Issaquah, Washington, USA:



Mr. Charles Krebs


Specimen: Rotifer Floscularia ringens feeding. Its rapidly beating cilia (hair-like structures) bring water containing food to the rotifer
Technique: Differential interference contrast microscopy


I happen to like this Honorable Mention entry by Gerd Guenther of Duesseldorf Germany:

Mr. Gerd Guenther

Specimen: Stem section of Fragesia sp., garden bamboo, showing a vascular bundle
Technique: Fluorescence, ca. 200x


You can see the full gallery of winners here.

The deadline for next year's contest is Sept. 30, 2012.  If you're interested in entering, you can read the rules here.

Tuesday, December 27, 2011

Hospital isolation and delirium


Some hospital patients must be kept in isolation, either for their own safety or for the safety of others. They might be severely immuno-compromised, or extremely contagious. In either case, keeping such patients apart can save lives.  Unfortunately, such precautions may come at a cost.  It turns out that patients who become isolated are 1.75 times as likely to develop delirium.

For this retrospective study, Hannah Day and her colleagues from the University of Maryland School of Medicine examined the records of over 42,000 non-psychiatric patients admitted to a hospital over a two-year period.  Those that had to be transferred to isolation wards suffered from delirium more often than their non-isolated cohorts.  Interestingly, patients who began their hospital stay with contact precautions were not more likely to develop delirium.

There are a number of possibilities for this finding.  First, patients who are transferred to isolation wards midstay may be sicker than those who are isolated at admission.  After all, patients who require such a transfer have evidently taken a turn for the worse.  Second, it may be more traumatic for patients to suddenly find themselves in isolation when they weren’t expecting to need those precautions.  By the way, delirium is not a permanent condition like dementia.  It's a temporary state of confusion.

In any case, I wonder if the Trinity Medical Center’s duct tape system would be able to alleviate some of these problems. 

Monday, December 26, 2011

Flight evolution via stability flapping


Denver Fowler and his colleagues from Montana State University and from Brown University have some new theories about the habits of a group of theropod dinosaurs called Deinonychus.  Their ideas, which form the basis of their ‘Raptor Prey Restraint (RPR)’ model, have implications not only for the behavior of these meat-eating dinosaurs, but possibly for the evolution of flight as well.

Skeleton of Deinonychus at the Field Museum in Chicago.

You may be familiar with Deinonychus’s cousin, Velociraptor from the Jurassic Park movies. These are smallish dinosaurs with giant claws on their second toes.  In popular mythology, the claws are used to slash prey.  However, Fowler and his team compared the feet of Deinonychus to those of living raptors (hawks and eagles).  These birds also have large talons, but they use them to immobilize their prey, not to disembowel their victims.  In the same way, the paleontologists propose that Deinonychus used its claws to grip large prey, which could then be eaten alive.

Further study of living birds of prey shows that they will sometimes flap their wings while gripping prey that is too large to carry off.  They do so in order to stabilize their position on top of their struggling quarry. Although Deinonychus would have been incapable of flight, its stubby wings would have been more than up to the job of helping it maintain its balance while subduing its dinner.  In other words, flapping as a means to stabilize position while feeding could have preceded powered flight. 

You can see an example of this sort of behavior displayed by an Eurasian Sparrowhawk below.  Note:  if you're sensitive about watching animals eat each other, you may want to skip this.



By the way, how cool is it that a person who studies bird evolution is named 'Fowler'?

Sunday, December 25, 2011

What to do with your discarded wrapping paper?


Turn it into biofuel!  At least, that’s what Richard Murphy and his colleagues from Imperial College London would like us all to do.  They studied the feasibility of converting many kinds of waste paper into ethanol and found that almost any kind of paper can be used.


The fermentation process could even cope with festive paper and card which has been 'contaminated' with the likes of glitter and sellotape [adhesive tape like Scotch brand for us Yanks].

The fuel derived from the Christmas cards and wrapping paper from within the United Kingdom alone would be more than enough to send a fleet of 250 double-decker buses on a trip around the circumference of the Earth. If all countries adopted this method to deal with paper waste, it could be an important step in replacing fossil fuels.  

Saturday, December 24, 2011

Less blood needed


Most healthy people have hemoglobin levels that fall between 12 and 18 grams per deciliter of blood (g/dl). Currently, patients undergoing surgery are routinely given blood transfusions if their hemoglobin levels drop below 10 g/dl or if they have any of a number of other risk categories, such as old age or heart disease.  Jeffrey Carson of Robert Wood Johnson Medical School and a large team of colleagues tested whether these rules could be safely relaxed for patients undergoing hip surgery.  This turned out to be the case, even for elderly patients.

Matched patients around eighty years old who required hip surgery were randomly assigned to two groups of about a thousand people each. The liberal group automatically received blood transfusions if their hemoglobin levels dropped below 10 g/dl. The restricted group did not receive blood unless their hemoglobin levels fell below 8 g/dl, or they showed clinical signs of anemia.  All patients were allowed transfusions at the discretion of their doctors.

Thirty and sixty days later, the patients were surveyed on their ability to walk.  The doctors hypothesized that maintaining a higher hemoglobin level might have allowed patients to work harder at their rehabilitation, resulting in greater independence two months after surgery.  Other consequences, such as rates of heart attack, pneumonia and death were also determined for the two groups. 

As I’m sure you’ve guessed, there were no significant differences between the two groups in either ability to walk unassisted, length of hospital stay or clinical outcomes. However, the patients in the restricted group used 65% fewer units of blood.  This is important because many hospitals suffer from a critical lack of transfusable blood.  If most surgical patients could safely be given little or no blood, it would free up the supply for patients who truly need transfusions.

Friday, December 23, 2011

Prevention of HIV infection


By starting anti-retroviral medicines early, heterosexual HIV patients can avoid giving the disease to their partners.  This information could drastically decrease the transmission rate of HIV, turning it from a pandemic to a manageable disease.

Myron Cohen of the University of North Carolina, Chapel Hill and his colleagues screened over 10,000 AIDS patients to find heterosexual couples composed of one HIV-infected and one uninfected partner.  Half of the HIV-positive partners in those 1763 couples were immediately started on a regimen of three daily anti-retrovirals, and the other half did not begin treatment until they became symptomatic.

Over the next three and a half years, there were 28 transmissions of HIV from infected to previously uninfected partners.  Of those, all but one occurred among the couples in the delayed treatment group.  That’s a difference of over 96% between the two treatment groups.  This result was so significant that the study was ended three years early (it was to have run through 2015), and all HIV-infected participants were offered anti-retroviral therapy.  In fact, Science magazine called this study the breakthrough of the year.

I have two comments about this study.  First, you may be wondering why doctors don’t routinely start their HIV patients on anti-retrovirals immediately upon diagnosis.  It simply was not known whether the drugs would be more effective at later stages of the disease. Also, many of these drugs have powerful side effects which patients may wish to avoid as long as possible. 

Second, because all the participants in this study were given standard care and counseling, including free condoms, I find it a bit disconcerting that any of the uninfected partners ended up with AIDS.  At least we now know how to limit that transmission.

Thursday, December 22, 2011

How to make a supernova

Two international teams of astronomers have confirmed a leading theory about how type Ia supernovae form. This is significant not only for supernova aficionados, but for anyone trying to understand the nature of the universe.   Type Ia supernovae were used to demonstrate the expansion of the universe and the existence of dark energy.


 
Caption: This is SN 2011fe in the Pinwheel Galaxy (M101) at maximum brightness, a composite of optical data from the Las Cumbres Observatory Global Telescope Network 0.8m Byrne Observatory Telescope at the Sedgwick Reserve and (purple) hydrogen emission data from the Palomar Transient Factory.
Credit: B.J. Fulton (LCOGT) / PTF

The current theory is that type Ia supernovae require a binary system. The exploding star is thought to be a white dwarf, the normally quiescent stage at the end of a small star’s lifetime.  When a star below a certain mass runs out of fuel, it first expands dramatically and then collapses into a dense package that can no longer generate energy.  This is the fate that awaits our Sun, in about five billion years.

For most white dwarfs, this is the end of the line, a quiet retirement of slowly dissipating heat and energy.  However, if the white dwarf has a companion star (thought to be a red giant), it can steal matter from that star, effectively rebooting itself.  If it steals too much energy too quickly, the white dwarf will explode into a type Ia supernova.

In August, there was a supernova in the Pinwheel galaxy that we were lucky enough to observe just eleven hours after the explosion.  Actually, since supernova SN 2011fe is 21 million light years away, the event really occurred 21 million years minus eleven hours ago, last August.  Don’t you love cosmology? 

In any case, analysis of the event showed that the explodee couldn’t have been more than a tenth of the radius of the Sun.  In other words, it was indeed a white dwarf.  On the other hand, while the identity of the companion star is not known, it was definitely not a red giant, as previously assumed.  This means that although type Ia supernovae do appear to involve white giants in binary systems, the second star in the system may be more variable than expected.

Wednesday, December 21, 2011

Just for fun: Red Tide



Man's Best Media produced this Red Tide video.  The surfer stirs up the bioluminescent phytoplankton Lingulodinium polyedrum to produce the stunning effects.





Hat tip:  Jennifer Ouellette.

Tuesday, December 20, 2011

Exoplanet in the habitable zone


NASA’s Kepler mission is specifically designed to search for habitable planets.  Among the thousands of candidate planets found in the past few years is Kepler-22b, the first non-solar planet confirmed to orbits within the habitable zone of its star

Let’s be clear about what this means.  This does not mean that Kepler-22b contains life, or even that it could sustain life.  All it means is that the planet orbits at the correct distance from its star so that liquid water could form on its surface.  We don’t yet know if there’s any water actually there.  In fact, we don’t even know whether the planet is rocky or gaseous, though at only 2.4 times the radius of the Earth, it could well have a solid surface.

This diagram compares our own solar system to Kepler-22. Kepler-22's star is a bit smaller than our sun, so its habitable zone is slightly closer in. The diagram shows an artist's rendering of the planet comfortably orbiting within the habitable zone, similar to where Earth circles the sun

This diagram compares our own solar system to Kepler-22, a star system containing the first "habitable zone" planet discovered by NASA's Kepler mission.
Image credit: NASA/Ames/JPL-Caltech

Because NASA requires three transits (views of the planet passing in front of its star) of an exoplanet to confirm its existence and position, it can take years to verify a finding.  In this case, Kepler-22b was first seen by William Borucki and his team at NASA Ames Research Center just three days after the launch of the Kepler mission, back in 2009.  The third transit was not observed until the end of 2010.

Monday, December 19, 2011

Gene therapy for hemophilia


There may be a cure in sight for hemophilia patients.  Researchers led by Amit Nathwani of University College London, along with colleagues from many other institutions have successfully used gene therapy to treat hemophiliacs. This amazing development would not only extend and improve the lives of hemophiliacs, but could be the beginning of a new era of treatments for other genetic diseases.

Hemophilia is a blood-clotting disorder caused by a genetic defect.  Specifically, people with hemophilia B (also called ‘Christmas disease’ after Stephen Christmas, a young sufferer of this condition) are born with a mutation in the gene for the protein factor IX (FIX).  Because this gene is located on the X chromosome, the disease occurs almost exclusively in boys.  To be a hemophiliac, a girl would have to be the misfortunate product of a hemophiliac father and a carrier mother.

Hemophilia patients need regular infusions of the clotting agents they lack in an effort to alleviate symptoms. In contrast, gene therapy, the replacement of faulty or mutated genes with normal versions of those same genes, would permanently cure the patients.  Although a promising idea, little progress has been made due to a number of difficulties, including the problem of providing genetic material in a way that won’t adversely affect other genes or alert the immune system. 

The researchers got around these problems by using a modified adenovirus, to which most people do not exhibit strong immune reactions, as a vector. Six patients with hemophilia B, each of whom had required supplementation with FIX protein between one and three times per week, were infused with the FIX-adenoviruses.  After treatment, their FIX levels remained stable at between 2 and 12% of normal (all had been below 1% prior to the treatment) for up to 15 months.  Some of the patients did require extra FIX protein, but at a much lower rate than before the treatment.

This was obviously an extremely small study.  Much more work must be done before gene therapy can be approved for general usage.  For one thing, the optimal dosage for delivering FIX must be determined. Also, it’s too early to tell how long the treatment will last, or whether it will produce any unforeseen consequences.  For now, the doctors and patients alike have reason to celebrate.  

Sunday, December 18, 2011

How to heal a broken bone


Is it better to rest an injured limb completely or to begin using it as soon as possible?  According to a study by Robert Guldberg and his colleagues from the Georgia Institute of Technology, the answer is a little of both.  The best choice is to immobilize a broken bone for about four weeks, and then to start applying compressive forces to the injury.  At least, that’s the case for rats.

The scientists created gaps in rat limb bones and then seeded those gaps with a potent bone growth factor (human bone morphogenetic protein-2).  All the rats had plates screwed onto their injured legs to protect them from mechanical forces.  Some of those plates were rigid, whereas others had a release mechanism that allowed the bone to be compressed. 

Rats whose broken bones were immediately subjected to compressive loads did not heal very well.  The mechanical forces applied at the very beginning of the treatment prevented blood vessels from spreading into the injured area.  These rats suffered up to a 75% loss in bone formation.  However, the benefit of having the rigid plate only lasted for the first four weeks of healing.  After that time, the rats with the compressible plates began to fair better. 


 
Micro-computed angiography reconstructions of blood vessel formation in the area of the defect
Top: when it experienced no mechanical force for seven weeks
Bottom: when mechanical forces were exerted on the injury site beginning after four weeks for a duration of three weeks.
Credit: Joel Boerckel.

If this data applies to humans, it suggests that broken bones should only be immobilized for a few weeks after an injury.  And I certainly hope it does apply to humans since I’d hate to think of these rats going through these procedures for nothing.

Saturday, December 17, 2011

Don’t eat raw cookie dough



Just when you were congratulating yourself on saving time on your holiday baking, news that prepackaged raw cookie dough can make you ill. Karen Neil and her colleagues from the Centers for Disease Control (CDC) linked 77 cases of Escherichia coli O157:H7 back in 2009 to ready-to-bake commercial cookie dough. Luckily, none of the afflicted people died, though several had to be hospitalized.

I had heard that you should not consume raw cookie dough in order to avoid the Salmonella that can lurk in raw eggs.  However, manufacturers of commercial cookie dough use pasteurized eggs in their mixes.  The scientists at the CDC instead suspect that the E. coli infection originated in a contaminated batch of flour.  Unfortunately, they were not able to confirm this hypothesis. Although 94% of the patients who became ill with E. coli O157:H7 over a few weeks in 2009 reported having eaten raw cookie dough, testing revealed very few product samples contaminated with the bacteria. It’s not clear how the cookie dough became contaminated, if in fact it was the dough that was at fault.

Still, the doctors at the CDC recommend that people not consume raw cookie dough, especially of the prepackaged commercial kind.  Seeing that this advice is unlikely to find much compliance (some of the patients admitted that they had had no intention of baking cookies when they bought the raw dough), doctors are asking manufacturers to make their product safe for raw consumption.  Some companies have responded by switching to heat-treated flour. 


Glob of raw cookie dough, by Ginny, July 25, 2008.



Friday, December 16, 2011

Are chimps synesthetes?


A new study by Vera Ludwig of Humboldt-Universit√§t zu Berlin and Ikuma Adachi and Tetsuro Matsuzawa from Kyoto University suggests that chimpanzees can be synesthetes.  If true, this implies that synethesia predates the evolutionary split between humans and chimpanzees, about six million years ago.

Synesthesia is a cross-firing of the senses. For example, a person may perceive particular digits to have specific colors, sounds, shapes or even personalities.  Although only about 1% of the population identify as synesthetes, most people display mild symptoms of the condition.  For example, people tend to associate high-pitched tones with light colors and low-pitched tones with dark colors. 

Ludwig and her team gave 33 humans and 6 chimps touchscreens and asked them to select a large square that was the same color (black or white) as a small indicator square.  The apes were given fruit treats for correct answers.  It’s not clear what the human subjects were given. 

As each new set of squares appeared, either a high tone or a low tone was played.  Although all the participants did extremely well, humans and chimps were quicker at picking the right square when the sound matched the color.  In the video below, you can see the chimp hesitate briefly before picking the correct black square when a high tone is played.

Is this really synesthesia?  Some researchers, such as Danko Nikolic, at the Max Planck Institute are skeptical.  I have to agree with him.  I think it would only truly be an example of synesthesia if the subjects heard a high tone when presented with a white square even if no sound was actually playing, something that would be exceedingly difficult to test in chimps.

Thursday, December 15, 2011

Just for fun: Fun Science

Charlie McDonnell self-describes himself as 'an English twenty-something who makes videos'.  He's being way too modest.  Here's one of his offerings about time travel.





Hat tip:  Bad Astronomy.


BTW, Charlie also has videos about his visit to the Doctor Who set, which automatically makes him my hero.

Wednesday, December 14, 2011

Finding the Higgs Boson


Two separate teams (ATLAS and CMShave found evidence of the elusive Higgs Boson, whose existence is theorized to explain why things have mass.  While this is not conclusive proof that the Higgs exists, the new data does make it much more likely that we will eventually confirm the existence of this subatomic particle.  


The Higgs Boson, if it exists, was expected to have a mass of about about 125 gigaelectronvolts (in particle physics, this is a measurement of both energy and mass; remember E = mc2), and both teams found a signal bump in exactly that range.  At this time, the chance of error (that the signal they found is not from the Higgs but is merely background noise) is only a few percent. That may seem definitive, but physicists won’t claim success unless they can lower the error rate to less than 0.0001%, something that may be done as more experiments are done.

As a refresher on the Higgs and on the Large Hadron Collider (where all the action is), I’m reposting this 2008 LHC rap:



For more details, here's an explanation by Phil Plait.

Tuesday, December 13, 2011

A rediscovered bumblebee


Here’s a bit of good news about bees.  Researchers at the University of California, Riverside have rediscovered an extremely rare bumblebee that hasn’t been seen in over fifty years.  The Cockerell’s Bumblebee was discovered in 1913 and, until its rediscovery in August of this year, hadn’t been encountered since 1956. 

 

A Cockerell’s Bumblebee.
Credit: G. Ballmer, UC Riverside

Not only is the Cockerell’s Bumblebee rare today, it was never abundant.  Only 23 specimens had ever been found, all within about 300 square miles in the White Mountains of New Mexico.  In fact, entomologists once thought the bee was merely a color variant of a more common bumblebee. Genetic tests have now shown the bee to be a unique species, though little is known about how it makes its living.

Considering the widespread die-outs of many bee populations in recent years, I think it’s nice to hear about a bee that made a come back.  

Monday, December 12, 2011

Inadvertent fecal transplants


If you read yesterday’s post, you know that fecal transplants can be effective weapons against microbial pathogens.  That’s good news considering that medical students do not know when to wash their hands.

Eighty-five medical students at Hannover Medical School who were about to begin clinical studies (meaning that they were to begin examining and treating real patients) were given a questionnaire asking whether hand washing was required under various scenarios.  For example, must you wash your hands after removing gloves?  Answer:  yes.  How about after touching a patient’s bed?  Also yes.  Only a third of the students got all the answers right.

Interestingly, the medical students predicted that they would have better hand-washing compliance than nursing students, when in fact the reverse was true.  Nursing students were much better at washing their hands than were medical students. 

Needless to say, this was a small study at a single school.  It does highlight the need for teaching students when to wash their hands and for ensuring that experienced health care professionals continue to exercise proper hand-washing protocols.  As helpful as they may be, nobody wants unsolicited fecal transfers.


Sunday, December 11, 2011

Something to look forward to—fecal transplants

Update 5/13: The FDA is now requiring doctors to use investigational new drug applications before performing the fecal transplants. Whether this leads to black market fecal centers is yet to be seen.

Update 10/12: Another study using donated human stool was recently conducted at Henry Ford Hospital. The results in terms of both efficacy and safety were extremely promising.

As unpleasant as it sounds, fecal transplants may be coming to a hospital near you.  Specifically, the microorganisms within the donated fecal samples can be used to eliminate pathogens such as Clostridium difficile.  No fewer than four studies about the efficacy of fecal transplants were presented at the 76th Annual Scientific Meeting of the American College of Gastroenterology last month.

C. difficile is a well named pathogen. Not only does it cause severe diarrhea, but it can also lead to a potentially life-threatening infection of the colon. In addition, C. difficile is often antibiotic-resistant. Normally, C. difficile is held in check by the ‘friendly’ bacteria in a person’s gut, but following antibiotic treatment, the good microbes are often decimated, leaving room for C. difficile to flourish.  By seeding the gut with a new supply of good bacteria, C. difficile may again be outcompeted to the point of extinction. At least, that’s the reasoning behind the fecal microbe transfer, and it appears to hold true.  In fact, over 90% of patients who undergo this procedure (many of whom have combated C. difficile unsuccessfully for years) have a full recovery.

One caveat: although the evidence is mounting that this procedure is safe and effective (to the point where investigator Lawrence Brandt of the Albert Einstein College of Medicine suggests it should be the first line of attack in treating C. difficile), it hasn’t been thoroughly tested.  For one thing, it’s hard to get NIH grants to study feces.

And in case you were wondering, doctors who perform this procedure sometimes suggest that patients recruit their own donors, often from spouses or other family members.  Now, that’s love.

Saturday, December 10, 2011

No reason to switch to presumed consent


There’s a severe shortage of organs available for donation in the United States.  According to the U.S. department of Health and Human Services, there are over 100,000 people currently waiting for an organ.  One suggestion for how to alleviate that situation has been to change our consent policy so that potential donors have to opt out rather than in.  However, a new study led by Dorry Segev of Johns Hopkins suggests that this would be of little help.

In the U.S., we have an opt in system of donation consent.  In other words, you have to actively agree to become a donor.  Many other countries choose an opt out system, also called presumed consent.  In those nations, each person is assumed to be a donor unless they specifically refuse while alive.  At first glance, it seems that presumed consent would have to garner more donations since many people with no objection to donating organs may never have bothered to opt in.  However, comparisons with donation rates in other countries show that this is not the case.  In fact, the U.S. ranks third in donation rates, well above many countries with opt out policies.

Apparently, the type of legal consent obtained makes little difference.  This may be because even in countries with presumed consent, family members are consulted prior to donation.  Only in Portugal (with the second highest donation rates, below only Spain) would doctors ignore family objections. 

Rather than switching to a presumed consent system, which would be costly and of dubious value, the authors suggest that the U.S. copy other aspects of Spain’s system.  Spain has dedicated transplant physicians at hospitals, ready to approach families and to assess and prepare patients.  Beyond that, the most important thing is to educate the public to discuss their wishes with their next of kin.

Friday, December 9, 2011

Virtual train dilemma


David Navarrete and his colleagues from Michigan State wondered how people would react to moral dilemmas within a virtual world. They used the classic runaway train scenario for their test, but rather than presenting it as a hypothetical situation, they immersed their subjects in a three-dimensional virtual world.  The change in venue made little difference.

The scenario runs as follows.  An unstoppable train is heading down a track toward five people who have no chance to escape.  There is a switch in the track that can divert the train onto a sidetrack just in time, but there’s one person on that sidetrack.  You control the switch.  Do you do nothing and let the train kill the five people, or do you throw the switch and let the train kill the single person?

If you’re like most people, you’ll throw the switch.  In Navarrete’s virtual study, over 90% of people chose to sacrifice one person to save five, a percentage which is consistent with nonvirtual tests.

I have a problem with this study.  Being in a virtual world, however realistic, does not change the fact that the subjects know that no one is really being killed.  Thus, I don’t see how this is an improvement on simply asking people what they’d do.  If anything, you might be testing how much participants want to see virtual people get hit by trains.

You can see a 2D adaptation of the test below.


Thursday, December 8, 2011

Medical marijuana for the win


Sixteen states have now passed medical marijuana laws (MML), allowing physicians to prescribe marijuana to patients who can either grow it themselves or obtain it from legal growers.  Have there been any unforeseen consequences of this change?  According to a preliminary report by Mark Anderson of Montana State University and Daniel Rees from the University of Colorado, Denver, legalizing marijuana may be significantly reducing traffic fatalities.

Traffic fatalities (as reported by the Fatality Analysis Reporting System) decreased by 9% after the implementation of MMLs.  Why should this be so?  After all, marijuana does have detrimental affects on one’s ability to drive.  Distance perception, hand-eye coordination and reaction time are all adversely affected by marijuana usage, just as they are by alcohol consumption.

For one thing, unlike drunk drivers, who tend to speed and take risks, stoned drivers tend to compensate for their defect by driving more slowly and carefully.  Therefore, using marijuana rather than alcohol would be of benefit to motorists (though obviously, using neither would be preferable--using cannabis is also associated with car crashes).  Data from the Beer Institute confirm that beer sales do fall upon the passage of MMLs, suggesting that some people switch from alcohol to marijuana when the latter is available.

Perhaps even more significantly, because people can legally drink in public places, they often find themselves in need of transportation home, which they may unwisely provide for themselves.  The often problematic legal nature of medical marijuana ensures that it is primarily used in the home.

By the way, a 9% decrease in traffic fatalities is nothing to sneeze at.  This is about the same savings in lives achieved by mandatory seat belt laws.  It does make one wonder what would happen if all marijuana usage were decriminalized.

Wednesday, December 7, 2011

Just for fun: Small world competition



Since 1974, Nikon has hosted the Small World Photomicrography Competition. Photographs must involve some type of light microscopy but can encompass any subject.  Prizes are given for originality, informational content, technical proficiency and visual impact.


The 2011 grand prize winner was this submission by Igor Siwanowicz of the Max Planck Institute.  In case you don't recognize the creature depicted below, it's a lacewing larva magnified 20x.


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You can see all the winners and honorable mentions here. Personally, I like the following picture of a 630x magnification of freshwater ciliates undergoing conjugation, submitted by Gerd Guenther.


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If you'd like to enter the contest next year, here are the rules.  Make sure your entry is in by the April 30, 2012 deadline.

Tuesday, December 6, 2011

Hot flashes can persist for years after menopause


This was the unfortunate conclusion of a study conducted by scientists from King’s College London and from the Gynecological Cancer Research Centre.  If you are in the majority of women who will suffer from either hot flashes (HF) or night sweats (NS) during menopause, you may have over a decade of symptoms to look forward to.

The researchers sent questionnaires to 15,000 post-menopausal women, asking them about their menopausal symptoms.  Of the over 10,000 respondents, 90% had experienced HF and/or NS on a regular basis, and over half of them were still experiencing those symptoms even though it had been an average of ten years since they went through menopause.

There are factors that can affect the severity of menopausal symptoms.  Smoking, alcohol consumption, anxiety and weight all have negative effects on menopause.  That’s no surprise.  What's disconcerting is that the symptoms last for so long. 

Health professionals need to be aware that women can still have hot flushes and night sweats in their late 50s and 60s.

Monday, December 5, 2011

Don’t be so quick to target invasive species


Invasive species can wreak havoc on an ecosystem.  A case in point is the notorious ship rat (Rattus rattus), which has been an unwelcome guest at every port visited by humans.  The North Island of New Zealand can thank the ship rat for the nearly complete elimination of all native vertebrates.  Unfortunately, many of the native plants relied on those vertebrates for pollination services.  But don’t worry, this story does have a happy ending.  A substitute pollinator has apparently taken over the duties vacated by the missing vertebrates.  That creature is… the ship rat.

David Pattermore and David Wilcove of Princeton University studied the pollination of three native New Zealand plants growing on North Island and in a nature reserve called Little Barrier Island.  Although the native vertebrate population had been depleted from North Island, it thrives in abundance on Little Barrier Island.  Surprisingly, the pollination rate for the plants was similar in the two areas. 

The primary pollinators on Little Barrier Island are the endemic birds and bats.  On North Island, that job is done by ship rats and by an introduced species of bird known as the silvereye.  Apparently, ship rats had replaced the very pollinators that they drove to extinction. 

This creates a tricky problem for conservationists trying to hold back the flood of invasion by non-native species.  Scourging ship rats from the North Island would do the native plants no favors.  After all, the plants don’t care whether it’s a rat or a bat that carries their pollen around.   The more that is understood about the current role of introduced species within an ecosystem, the better those locations can be managed.  At the very least, every effort must be made to reintroduce native pollinators before removing invaders.

You can see Pattermore’s explanation below.