chronobiology
clock | October 23, 2006How birds know when and where to migrate (from April 03, 2006)
I've never ever expected to see the word "Zugunruhe" in New York Times! But here it is. It is one of my most favourite words of all times (right after "elusive"), and is even described pretty accurately:
Zugunruhe brooks no confusion. It has a Germanic certainty, and there can be no doubt what it means, once you know what it means. I confess that I only learned the word this week. If I understand the paper about it by Barbara Helm of the Max Planck Institute for Ornithology in Andechs, Germany, and the late Eberhard Gwinner in…
clock | October 19, 2006Randy Nelson is a wonderful person, an engaging speaker and the author of the best textbook on Behavioral Endocrinology. I heard that he is also a great teacher which does not surprise me and he has a talent for attracting some of the best students and postdocs to work in his lab. Oh, by the way, he also does some great research.
For decades, the study of seasonality and photoperiodism was a hustling bustling field, until everyone jumped on the clock-gene bandwagon. Randy Nelson is one of the rare birds to remain in the photoperiodism field, coming out every year with more and more…
clock | October 18, 2006This week's Ask a ScienceBlogger question is:
A reader asks: Is severely regulating your diet for a month each year, as Muslims do during Ramadan, good for you?
There is no way I can get out of this one! As far as I know, I am the only one here who actually did research on fasting! Mind you, it's been about 5 years since I last delved deep into the literature on the effects of fasting and feeding on various body functions, mainly body temperature and circadian rhythms, but I can try to pull something out of my heels now.
I'll try to somehow systematize this, by breaking the problem down…
clock | October 18, 2006Since this is another one of the recurring themes on my blog, I decided to republish all of my old posts on the topic together under the fold. Since my move here to the new blog, I have continued to write about this, e.g., in the following posts:
Preserving species diversity - long-term thinking
Hot boiled wine in the middle of the winter is tasty....
Global Warming disrupts the timing of flowers and pollinators
Global Warming Remodelling Ecosystems in Alaska
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Clocks, Migration and the Effects of Global Warming (December 23, 2005)
Circadian…
clock | October 16, 2006Nothing too complicated today, but something you should all know (from March 13, 2006).
I have mentioned this in my very first post here: in a natural state, humans do not sleep a long consecutive bout throughout the night. The natural condition is bimodal - two bouts of sleep interrupted by a short episode of waking in the middle of the night.
In today's New York Times, there is an article about this:
Sleep Disorder? Wake Up and Smell the Savanna by RICHARD A. FRIEDMAN, M.D.:
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Many patients tell me they have a sleep problem because they wake up in the middle of…
clock | October 9, 2006
A January 20, 2006 post placing a cool physiological/behavioral study into an evolutionary context.
There are two main hypotheses - not mutually exclusive - for the adaptive value of having a circadian clock. One is the Internal Synchronization hypothesis, stating that the circadian clock serves to synchronize biochemical and physiological processes within the body. The second is the External Synchronization hypothesis, stating that the circadian clock serves to syncronize the physiology and behavior to the natural environment.
The prediction from the Internal Hypothesis is that circadian…
clock | October 6, 2006Considering that circadian clocks were first discovered in plants, and studied almost exclusively in plants for almost a century before people started looking at animals in the early 20th century, it is somewhat surprising that the molecular aspects of the circadian rhythm generation mechanisms have lagged behind those in insects, vertebrates, fungi and bacteria. It is always nice to see a paper reporting a discovery of a new plant clock gene:
New function for protein links plant s circadian rhythm to its light-detection mechanism:
Plants set their clocks by detecting the light cycle, and…
clock | October 5, 2006Study says no video games on school nights:
According to Dr. Iman Sharif, the results were clear-cut. "On weekdays, the more they watched, the worse they did," said Dr. Sharif. Weekends were another matter, with gaming and TV watching habits showing little or no effect on academic performance, as long as the kids spent no more than four hours per day in front of the console or TV. "They could watch a lot on weekends, and it didn't seem to correlate with doing worse in school," noted Dr. Sharif.
The study was using self-reporting by kids, which has its problems, but is OK in this case, I…
clock | October 2, 2006
From January 20, 2006, on the need to check the model-derived findings in non-model organisms.
There are pros and cons to the prevalent use of just a dozen or so species as standard laboratory models. On one hand, when a large chunk of the scientific community focuses its energies on a single animal, techniques get standardized, suppliers produce affordable equipment and reagents, experiments are more likely to get replicated by other labs, it is much easier to get funding, and the result is speedy increase in knowledge.
On the other hand, there are drawbacks. One is narrow focus which can…
clock | September 25, 2006
A very cool study that I could not help but comment on (January 18, 2006)...
A brand new paper is making a splash in the field these days - so much that you can find the press release in three places: here, here and here, this last one being the coolest as it contains a movie and three podcasts!
One of the biggest problems in circadian biology is to account for such a long time - 24 hours - it takes for the whole transcription-translation feedback loop to run its course through a single cycle. Biochemical reactions tend to happen at much shorter time scales. Some mathematical models tried…
clock | September 20, 2006Over 1.6 Million Americans Use Alternative Medicine For Insomnia Or Trouble Sleeping:
A recent analysis of national survey data reveals that over 1.6 million American adults use some form of complementary and alternative medicine (CAM) to treat insomnia or trouble sleeping according to scientists at the National Center for Complementary and Alternative Medicine (NCCAM), part of the National Institutes of Health.
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Those using CAM to treat insomnia or trouble sleeping were more likely to use biologically based therapies (nearly 65 percent), such as herbal…
clock | September 19, 2006So, is extreme "larkiness" due to overphosphorilation or underphosphorilation of PERIOD2?
Hypotheses get tested, studies conflict with each other and, in the end, there is a resolution. In this case, we are still waiting for resolution. Science marches on.
clock | September 18, 2006In this post from April 06, 2006, I present some unpublished data that you may find interesting.
Understanding the role of serotonin in depression has led to development of anti-depressant drugs, like Prozac. Much of the research in this area has been performed in Crustaceans: lobsters and crayfish. The opposite behavioral state of depression, something considered a normal state, could possibly best be described as self-confidence.
Self-confidence is expressed differently in different species, but seems to always be tied to high status in a social hierarchy. In crayfish, self-confidence is…
clock | September 15, 2006Students not getting enough sleep:
College students may believe they are being more productive when they sleep less, but in reality it is causing harm to their bodies. The National Sleep Foundation points out that receiving less than six hours of sleep a night is associated with 1.7 times greater risk of disease, according to www.sleepfoundation.org. The chance of decreased academic performance, driving accidents, colds and flu and mental illnesses are all increased.
Workplace fatigue risky business at 30,000 ft.:
Fatigue is worsened when lack of sleep is coupled with a disruption to the body…
clock | September 12, 2006Scientists discover molecule behind birds' magnetic sense:
"Some birds, notably migratory species, are able to detect the Earth's magnetic field and use it to navigate. New results from a team of Franco-German researchers suggest that light-sensitive molecules called cryptochromes could be the key to the birds' magnetic sense.
They did not suggest it - they tested a 10-year old hypothesis.
Cryptochromes are photoreceptors which are sensitive to blue light, and they are involved in a number of processes linked to the circadian cycle, such as growth and development.
Caution: cryptochromes have…
clock | September 11, 2006The fourth part of a four-part series on the topic, this one from April 02, 2006....
This being the National Sleep Awareness Week and on the heels of the recent study on sleep of adolescents, it is not surprising that this issue is all over the media, including blogs, these days.
I have written about it recently several times. I present some science and some opinion here and add a little more science and much more opinion here.
You can look at media coverage here and listen to an excellent podcast linked here. Some basic underlying science is covered here.
All of this targets highschoolers…
clock | September 11, 2006This is the third part of the series on the topic, from April 01, 2006...
This being the National Sleep Awareness Week and in the heels of the recent study on sleep of adolescents, it is not surprising that this issue is all over the media, including blogs, these days.
I have covered this issue a couple of times last week, e.g., here, here and here. Recently, Lance Mannion wrote an interesting post on the topic, which reminded me also of an older post by Ezra Klein in which the commenters voiced all the usual arguments heard in this debate.
There are a couple of more details that I have not…
clock | September 11, 2006
Here is the second post on the topic, from March 28, 2006. A couple of links are broken due to medieval understanding of permalinks by newspapers, but you will not miss too much, I hope....
Health Journal: Doctors probe why it's hard for many kids to get up (also Night Owls: Disorder may cause teens to sleep less):
"The parents get stigmatized as not having control over their kids when they can't get them to school in time," says James Wyatt, co-director of the sleep-disorders center at Rush University Medical Center in Chicago who is conducting research looking for ways to better diagnose…
clock | September 11, 2006
Earlier this year, during the National Sleep Awareness Week, I wrote a series of posts about the changes in sleep schedules in adolescents. Over the next 3-4 hours, I will repost them all, starting with this one from March 26, 2006. Also check my more recent posts on the subject here and here...
I am glad to see that there is more and more interest in and awareness of sleep research. Just watch Sanjay Gupta on CNN or listen to the recent segment on Weekend America on NPR.
At the same time, I am often alarmed at the levels of ignorance still rampant in the general population, and even more…
clock | September 10, 2006This kind of ignorant bleating makes me froth at the mouth every time - I guess it is because this is my own blogging "turf".
One of the recurring themes of my blog is the disdain I have for people who equate sleep with laziness out of their Puritan core of understanding of the world, their "work ethic" which is a smokescreen for power-play, their vicious disrespect for everyone who is not like them, and the nasty feeling of superiority they have towards the teenagers just because they are older, bigger, stronger and more powerful than the kids. Not to forget the idiotic notions that kids…