Clock News:
To sleep or not to sleep: the ecology of sleep in artificial organisms: We systematically varied input parameters related to the number of food and sleep sites, the degree to which food and sleep sites overlap, and the rate at...
Posted on May 15, 2008 7:39 AM • 0 Comments • 0 TrackBacks
When teaching human or animal physiology, it is very easy to come up with examples of ubiqutous negative feedback loops. On the other hand, there are very few physiological processes that can serve as examples of positive feedback. These include...
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Posted on May 4, 2008 4:53 PM • 3 Comments • 0 TrackBacks
As we mentioned just the other day, studying animal behavior is tough as "animals do whatever they darned please". Thus, making sure that everything is controlled for in an experimental setup is of paramount importance. Furthermore, for the studies to...
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Posted on April 30, 2008 4:52 PM • 0 Comments • 0 TrackBacks
Two interesting papers came out last week [from the Archives - click on the clock logo to see the original post], both using transgenic mice to ask important questions about circadian organization in mammals. Interestingly, in both cases the gene...
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Posted on April 29, 2008 4:50 PM • 1 Comments • 0 TrackBacks
This post is a relatively recent (May 24, 2006) critique of a PLoS paper....
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Posted on April 27, 2008 4:54 PM • 0 Comments • 0 TrackBacks
'Fiona' Gene Controls Flower's Physiologic Clock: Scientists have found a new gene that regulates the daily and yearly physiological cycles of flowering and seeding. POSTECH researchers, led by Nam Hong-gil and Kim Jeong-sik, said that they named the gene FIONA1...
Posted on February 25, 2008 10:41 AM • 0 Comments • 0 TrackBacks
I found two articles interesting to me in today's issue of PLoS Computational Biology - the first one about becoming a good scientist, the other on circadian rhythms: On the Process of Becoming a Great Scientist: In the vein of...
Posted on February 14, 2008 6:37 PM • 0 Comments • 0 TrackBacks
Washington Post has an article on how to plant your own floral clock, just like the one built by Linnaeus....
Posted on February 9, 2008 11:23 AM • 3 Comments • 0 TrackBacks
It's rare that an article combines my two interests - in biological clocks and politics. This one does: Circadian rhythms differ for the king and the president: One is a night owl who likes to do business after midnight. The...
Posted on January 14, 2008 12:09 AM • 2 Comments • 0 TrackBacks
I had no time to read this in detail and write a really decent overview here, perhaps I will do it later, but for now, here are the links and key excerpts from a pair of exciting new papers in...
Posted on January 7, 2008 8:14 PM • 1 Comments • 0 TrackBacks
Shift Work May Be Cancer Risk: In an announcement to be published Saturday in the journal Lancet Oncology, the International Agency for Research on Cancer, part of the World Health Organization, will label shift work as a "probable cause" of...
Posted on November 30, 2007 9:18 AM • 2 Comments • 0 TrackBacks
Plano teen wins regional science award, moves on to national competition: The awards, which recognize exceptional achievement in science, were announced Saturday at the University of Texas at Austin. Alexander, who won a $3,000 scholarship, was honored for developing a...
Posted on November 4, 2007 12:06 PM • 1 Comments • 0 TrackBacks
I was fantastically busy this past week, so I failed to alert you to new articles published in PLoS Computational Biology, PLoS Pathogens, PLoS Genetics and PLoS Neglected Tropical Diseases. I have posted my picks from the latter one. This...
Posted on November 3, 2007 11:15 PM • 2 Comments • 0 TrackBacks
I am sure I have ranted about the negative effects of DST here and back on Circadiana, but the latest study - The Human Circadian Clock's Seasonal Adjustment Is Disrupted by Daylight Saving Time (pdf) (press releases: ScienceDaily, EurekAlert) by...
Posted on October 24, 2007 9:45 PM • 31 Comments • 0 TrackBacks
There are times when one would like to hang the whole human race and finish the farce. - Mark Twain...
Posted on October 10, 2007 3:54 AM • 0 Comments • 0 TrackBacks
When teaching human or animal physiology, it is very easy to come up with examples of ubiqutous negative feedback loops. On the other hand, there are very few physiological processes that can serve as examples of positive feedback. These include...
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Posted on September 27, 2007 1:19 PM • 5 Comments • 0 TrackBacks
Circadian clocks: regulators of endocrine and metabolic rhythms by Michael Hastings, John S O'Neill and Elizabeth S Maywood is a new and excellent review of the interaction between the clocks and hormones in mammals, focusing at the molecular level. The...
Posted on September 19, 2007 2:34 PM • 0 Comments • 0 TrackBacks
From June 26, 2006.......
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Posted on August 11, 2007 5:00 PM • 0 Comments • 0 TrackBacks
If you are one of the few of my readers who actually slogged through my Clock Tutorials, especially the difficult series on Entrainment and Phase Response Curves, you got to appreciate the usefulness of the oscillator theory from physics in...
Posted on July 31, 2007 1:57 PM • 1 Comments • 0 TrackBacks
Microarrays have been used in the study of circadian expression of mammalian genes since 2002 and the consensus was built from those studies that approximately 15% of all the genes expressed in a cell are expressed in a circadian manner....
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Posted on July 20, 2007 4:50 PM • 2 Comments • 0 TrackBacks
A very cool study that I could not help but comment on (January 18, 2006)......
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Posted on July 15, 2007 8:52 AM • 0 Comments • 0 TrackBacks
No other aspect of behavioral biology is as well understood at the molecular level as the mechanism that generates and sustains circadian rhythms. If you are following science in general, or this blog in particular, you are probably familiar with...
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Posted on July 14, 2007 8:59 AM • 2 Comments • 0 TrackBacks
If this gets more widely known (and, with this post, I am trying to help it become so), you can just imagine the jokes about the new challenges to the aviation industry and the renewed popularity of the Mile High...
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Posted on July 13, 2007 4:56 PM • 0 Comments • 0 TrackBacks
Menaker Awarded Farrell Prize in Sleep Medicine: Michael Menaker, professor of biology and an international leader in the field of circadian rhythm research, received the Peter C. Farrell Prize in Sleep Medicine from the Harvard Medical School Division of...
Posted on July 10, 2007 12:44 PM • 2 Comments • 0 TrackBacks
Surprise, surprise - a paper in Science is up there with a free online access (not the PDF, but the Full Text and that is something!): A Molecular Basis for Natural Selection at the timeless Locus in Drosophila melanogaster: Diapause...
Posted on July 3, 2007 2:14 PM • 0 Comments • 0 TrackBacks
Microarrays have been used in the study of circadian expression of mammalian genes since 2002 and the consensus was built from those studies that approximately 15% of all the genes expressed in a cell are expressed in a circadian manner....
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Posted on June 15, 2007 3:51 PM • 1 Comments • 0 TrackBacks
This article, of course, got my attention: Clocking In And Out Of Gene Expression Using steroid receptor coactivator-3 (SRC-3), they demonstrated that activation requires addition of a phosphate molecule to the protein at one spot and addition of an...
Posted on June 14, 2007 10:23 PM • 0 Comments • 0 TrackBacks
More stuff from SLEEP 2007, the 21st Annual Meeting of the Associated Professional Sleep Societies: Sleep Deprivation Affects Eye-steering Coordination When Driving: Driving a vehicle requires coordination of horizontal eye movements and steering. Recent research finds that even a single...
Posted on June 14, 2007 2:26 AM • 1 Comments • 0 TrackBacks
Children With Sleep Disorder Symptoms Are More Likely To Have Trouble Academically: Students with symptoms of sleep disorders are more likely to receive bad grades in classes such as math, reading and writing than peers without symptoms of sleep disorders,...
Posted on June 13, 2007 9:00 AM • 1 Comments • 0 TrackBacks
Sleep Deprivation Affects Airport Baggage Screeners' Ability To Detect Rare Targets: A lack of sleep may affect the performance of airport employees, which can, in turn, compromise the safety of airline passengers. Sleep deprivation can impair the ability of airport...
Posted on June 12, 2007 7:54 AM • 1 Comments • 0 TrackBacks
Wide Range Of Sleep-related Disorders Associated With Abnormal Sexual Behaviors, Experiences: A paper published in the June 1st issue of the journal SLEEP is the first literature review and formal classification of a wide range of documented sleep-related disorders associated...
Posted on June 3, 2007 2:09 PM • 2 Comments • 0 TrackBacks
If this gets more widely known (and, with this post, I am trying to help it become so), you can just imagine the jokes about the new challenges to the aviation industry and the renewed popularity of the Mile High...
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Posted on May 22, 2007 11:54 AM • 3 Comments • 0 TrackBacks
Review of some very cool new papers on Drosophila circadian clocks
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Posted on May 19, 2007 12:56 AM • 2 Comments • 0 TrackBacks
I recently mentioned a study reporting circadian oscillations of bacterial clock-proteins KaiA, KaiB and KaiC in a dish with no transcription and translation whatsoever - the oscillations being due entirely to polymerization of proteins. Now, a mathematical model of this...
Posted on May 18, 2007 12:03 AM • 2 Comments • 0 TrackBacks
This is going to be a challenging post to write for several reasons. How do I explain that a paper that does not show too much new stuff is actually a seminal paper? How do I condense a 12-page Cell...
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Posted on May 7, 2007 2:42 AM • 6 Comments • 0 TrackBacks
One chronobiological pioneer is leaving and another one is coming in. Gene Block is going to UCLA and Joe Takahashi is leaving Northwestern (What are Fred Turek and others going to do there without him? What happens to the Howard...
Posted on May 1, 2007 4:09 PM • 1 Comments • 0 TrackBacks
Thus reports The Scientist: Researchers from three different labs have identified a new circadian gene in the mouse, according to two papers in Science and one paper in Cell published online this week. Mutagenesis screens revealed that mutations in a...
Posted on April 26, 2007 6:00 PM • 8 Comments • 0 TrackBacks
This is the first study I know that directly tested this - the effects of rotating shifts on longevity - in humans, though some studies of night-shift nurses have shown large increases in breast cancers, stomach ulcers and heart diseases,...
Posted on April 22, 2007 1:06 PM • 7 Comments • 0 TrackBacks
I made only a brief mention of the study when the press release first came out, but the actual paper (which is excellent) is out now. It is on PLoS so it is free for all to see: Mania-like behavior...
Posted on April 12, 2007 9:00 AM • 0 Comments • 0 TrackBacks
One of the big questions in circadian research is how does the transcription/translation feedback loop manage to get stretched to such a long time-frame: 24 hours. If one took into account the normal dynamics of transcription and translation, the cycle...
Posted on April 2, 2007 10:58 AM • 0 Comments • 0 TrackBacks
A new paper just came out today on PLoS-Biology: Glucocorticoids Play a Key Role in Circadian Cell Cycle Rhythms. The paper is long and complicated, with many control experiments, etc, so I will just give you a very brief summary...
Posted on March 21, 2007 12:24 PM • 3 Comments • 0 TrackBacks
It has been known for quite a while now that bipolar disorder is essentially a circadian clock disorder. However, there was a problem in that there was no known animal model for the bipolar disorder. Apparently that has changed, if...
Posted on March 20, 2007 2:29 AM • 0 Comments • 0 TrackBacks
The most exciting thing about this study is that this is, as far as I am aware, the first instance in which it was shown that a circadian clock gene has any effect on sleep apart from timing of it,...
Posted on March 12, 2007 12:46 AM • 1 Comments • 0 TrackBacks
This news just came in: Charles F- Ehret died of natural causes on February 24th at his home in Grayslake, Illinois, a suburb of Chicago. His Wikipedia entry is quote short: Charles Frederick Ehret is a WWII veteran (Battle of...
Posted on March 3, 2007 11:02 PM • 1 Comments • 0 TrackBacks
This is a story about two mindsets - one scientific, one not - both concerned with the same idea but doing something very different with it. Interestingly, both arrived in my e-mail inbox on the same day, but this post...
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Posted on February 28, 2007 9:50 AM • 3 Comments • 0 TrackBacks
There are several journals dedicated to biological rhythms or sleep. Of those I regularly check only two or three of the best, so I often miss interesting papers that occur in lower-tier journals. Here is one from December 2006 that...
Posted on February 11, 2007 12:24 AM • 2 Comments • 0 TrackBacks
Two interesting papers came out last week, both using transgenic mice to ask important questions about circadian organization in mammals. Interestingly, in both cases the gene inserted into the mouse was a human gene, though the method was different and...
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Posted on February 5, 2007 6:48 PM • 0 Comments • 0 TrackBacks
In light of my post earlier today about the discrepanices between 'real time' and 'clock time' (or 'social time'), it is heartening that the Parliament in the U.K. wisely decided not to switch their clocks to the time the rest...
Posted on January 31, 2007 4:58 PM • 4 Comments • 0 TrackBacks
While study of Time-Perception is, according to many, a sub-discipline of chronobiology, I personally know very little about it. Time perception is defined as interval timing, i.e., measuring duration of events (as opposed to counting, figuring which one of the...
Posted on January 31, 2007 3:59 PM • 1 Comments • 0 TrackBacks
Time Zones as experimental tools - if you live in a Big City you are just like one of my experimental subjects!
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Posted on January 31, 2007 11:54 AM • 8 Comments • 0 TrackBacks
If you are interested in the background and recent history of the research on mammalian SCN in line of Erik Herzog's work I described in VIP synchronizes mammalian circadian pacemaker neurons and A Huge New Circadian Pacemaker Found In...
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Posted on January 1, 2007 11:58 AM • 0 Comments • 0 TrackBacks
Memory Experts Show Sleeping Rats May Have Visual Dreams: Matthew A. Wilson, professor of brain and cognitive sciences at MIT's Picower Institute for Learning and Memory, and postdoctoral associate Daoyun Ji looked at what happens in rats' brains when they...
Posted on December 20, 2006 10:01 AM • 1 Comments • 0 TrackBacks
If you really read this blog 'for the articles', you know some of my recurrent themes, e.g., that almost every biological function exhibits cycles and that almost every cell in every organism contains a more-or-less functioning clock. Here is a...
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Posted on December 19, 2006 1:52 PM • 2 Comments • 0 TrackBacks
Now behind the Wall, but plenty of excerpts available in this March 26, 2005 post......
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Posted on December 13, 2006 10:53 AM • 1 Comments • 0 TrackBacks
How does that work? (April 03, 2005)...
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Posted on December 11, 2006 11:00 AM • 0 Comments • 0 TrackBacks
No other aspect of behavioral biology is as well understood at the molecular level as the mechanism that generates and sustains circadian rhythms. If you are following science in general, or this blog in particular, you are probably familiar with...
Posted on December 5, 2006 2:52 PM • 0 Comments • 0 TrackBacks
Often a press release inflates the meaning of a research paper. Here is one example of it (from May 23, 2006):...
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Posted on November 20, 2006 11:01 AM • 1 Comments • 0 TrackBacks
This post is a relatively recent (May 24, 2006) critique of a PLoS paper....
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Posted on November 13, 2006 10:58 AM • 0 Comments • 0 TrackBacks
Chronic Jet-Lag Conditions Hasten Death in Aged Mice Researchers at the University of Virginia have found that aged mice undergoing weekly light-cycle shifts - similar to those that humans experience with jet lag or rotating shift work - experienced significantly...
Posted on November 6, 2006 2:54 PM • 9 Comments • 0 TrackBacks
There is nothing easier than taking a bad paper - or a worse press release - and fisking it with gusto on a blog. If you happen also to know the author and keep him in contempt, the pleasure of...
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Posted on October 26, 2006 12:00 PM • 11 Comments • 0 TrackBacks
As the paper linked to in the previous post explains, everything is connected - clocks, sleep, hunger, obesity and diabetes. An important part of understanding all these interconnections between clocks and food is to understand the food-entrainable clocks, i.e., how...
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Posted on October 24, 2006 10:42 AM • 0 Comments • 0 TrackBacks
Randy 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...
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Posted on October 19, 2006 11:50 AM • 0 Comments • 0 TrackBacks
Placing a cool physiological/behavioral study into an evolutionary context
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Posted on October 9, 2006 11:00 AM • 0 Comments • 0 TrackBacks
Considering 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...
Posted on October 7, 2006 1:49 AM • 0 Comments • 0 TrackBacks
Study 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...
Posted on October 5, 2006 11:59 AM • 2 Comments • 0 TrackBacks
Since every chemical induces a different response in the body dependent on the time of day when it is administered, I am not surprised that this also applies to caffeine: A new study at the Université de Montréal has concluded...
Posted on October 4, 2006 10:57 AM • 1 Comments •
