Is Your Job Making You Sick?

Back in 2007 I was surprised to see that the International Agency for Research on Cancer (a United Nations agency) had listed shift work as a suspected cancer causing factor. The reason for this was the belief that shift work disrupted normal hormonal circadian rhythms.  It has also been noted that people with jobs requiring shift work have higher rates of obesity, diabetes and cardiovascular disease.

A new publication by Frank Scheer and colleagues has examined the specific hormonal changes that occur when sleep-wake patterns are displaced and their affects on blood glucose, blood pressure, and appetite.

They found that displacing the normal sleep-wake cycle altered the normal secretion of cortisol and leptin and that the displacement was proportional to the degree of displaced sleep.  The displaced pattern of cortisol secretion led to significant hyperglycemia increasing the risk of diabetes.  In some cases the hyperglycemia following sleep displacement was high enough to be classified as prediabetic and in one case as diabetic.  These values were found in individuals who had normal blood glucose levels without sleep disruption.

Decreases in leptin secretion were also noted and this is associated with an increase in appetite, increasing the risk of obesity.   Blood pressure also rose although the hormonal cause of this rise was not clear.

For details see: Scheer FAJL, and others. 2009.  Adverse metabolic and cardiovascular consequences of circadian misalignment. Proceedings of the National Academy of Sciences in the USA. Vol 10. 1073 (PNAS early edition: March 10)

Science Nerds

When I first started research as a graduate student in the 1980s, I was struck by the way that manufacturers of high-tech science lab gear marketed their products.  An attractive woman in a lab coat leaning against a high speed centrifuge seductively telling you how fast her machine can pull down your microsomes.  Seemed like they were selling beer.

Here is an ad pushing a machine that replicates DNA--a thermocycler that carries out a technique call Polyermase Chain Reaction (PCR), a key procedure in DNA fingerprinting.  

I have one in the lab....... but it has never done this.

Source: blog.wired.com/wiredscience/

Evolution in Reaction

No surprise.  Fish populations are not just smaller because we have removed the larger members, they are smaller because those larger members are no longer contributing their genes to fish populations.  Only small fish are reproducing and now fish populations are naturally smaller and slower growing than they used to be.  We have known this for awhile.  Fish are evolving under the intense selective pressure of human fisheries.

David Conover and colleagues from Stony Brook University in New York, however, has discovered that by changing the way we harvest fish, we can reverse this trend and return large bodied fish to our oceans and lakes.  

But:

-It may take at least 80 years (probably longer) and

-All countries harvesting fish would have to agree to new harvesting methods.

Therefore:  fish are going to continue to get smaller.  

Photo Credit: me (Bluefin Travally, Cook Islands, 2004)

Science Life as Art

Anyone working on ants knows the name of Robert Trivers.  His work in the 1970s  on how evolution handles conflict within species led to some remarkable predictions.  In the case of ants, he examined the evolutionary conflict between queens and workers with respect to the ideal ratio of male and female offspring.  This led to some specific predictions regarding sex ratios in ants that have been largely supported by field observations.

His life and his work has now become a Broadway play.  Leave a Light On, written by Ann Marie Healy will be performed as part of the First Light Festival series this April at the Ensemble Studio Theatre.  For those a bit closer to New York than myself, Tickets can be purchased here.

The life of Robert Trivers has in some ways been as dramatic as the topic of conflict which has driven his academic career.  Most notably his friendship with Huey Newton, former chairman of the Black Panthers.  He and Newton actually published a paper together on the role of self-deception in the crash of an American airplane(Science Digest 1982 Vol 111:66-67.)

Photo credit: Robert Trivers taken by Nick Romanenko, Rutgers University

An Alternative to Work

The live web-cam run by National Geographic on Glover's Reef, just off the coast of Belize has to be one of the best sites on the web.

As an alternative to work it has no equal.  

Water conditions are a bit murky right now because of a series of winter storms that actually broke the cable controlling the camera. As a consequence the camera has been moved into a more secluded portion of the reef. 

To see the live web-cam, click here.  If you want to try and identify some of the fish you see, try clicking here (scroll down the right side).

Photo credit: Screen capture of live web-cam taken on March 02, 2009.

While You Were Sleeping

Early this morning the asteroid '2009 DD45' passed very close to Earth.  Well, within 72,000 km anyway, about twice the height of our geosynchronous satellites.

Discovered only 3 days ago, this asteroid is estimated to have a diameter of approximately 35 metres and was closing on the Earth at approximately 8 kilometres per second-- actually a bit slow for most asteroids.

Asteroids pass close to the Earth all the time, and frequently collide. Thirty five metres, however, is fairly big, and this can do a lot of damage.  No, it isn't the kind of asteroid that could end life on Earth by any means but depending on the density of the asteroid and the angle of approach it could cause a fair bit of local damage. In 1908 an asteroid of similar size leveled over 200 square kilometres of forest in Tunguska, Russia.

Slow moving asteroids tend not to explode in the atmosphere which is what caused so much damage in the Tunguska event.  However, the final crater from an impact with an asteroid of this size (assuming it was iron) would be almost a kilometre across.  

Tunguska size impacts are expected to occur about once every hundred years or so.  Not to worry though, Tunguska happened 101 years ago.  Hmmmmm.

If the physics of asteroid impacts interest you (and by physics I mean damage), take a look at the webpage created by Marcus, Melosh, and Collings.   

Photo Credit: Asteroid Ida, Galileo Spacecraft, Astronomy Picture of the Day (June 29, 1997)

Pssst...Wanna See a Comet?

For the past month backyard astronomers have been hoping that Comet Lulin would, as comets often unexpectedly do, brighten, and become an object visible to the naked eye.  Alas, binoculars are still needed.

Comet Lulin swung around the Sun on January 10th and is now heading out of the solar system. Fortunately it will still be visible, with binoculars, through March.

I've plotted the rough position of the Comet on the sky chart above.  It is near the constellation Leo right now (March 1) which is in the eastern sky.  If you view the moon around 8 or 9pm, simply turn and face in the opposite direction.  Leo is about the same elevation as the moon but will rise in the sky as the evening progresses.  Best viewing is around 11pm when Leo climbs higher in the sky, although at this time the elevation of the moon will not be a useful guide.

The comet will appear as a bit of a smudge. It has two tails, one trailing out behind it and another directly ahead of it which is formed by the solar wind blowing gas off of the comet.

Photo Credit:  Modified from Google Sky