clock | May 5, 2008You really think I am going to put this above the fold? No way - you have to click (First posted on July 7, 2006):
Today's lesson is on the reproductive anatomy of the domestic pig (Sus scrofa domestica), which probably applies to the wild species in the pig family as well. Although we may reflexively think about invertebrates when pondering diversity of copulatory organs, mammals are not too bad in that department either. After all, the sperm is delivered in some species into the vagina (e.g., dog), in others into the cervix (e.g., pig) and in yet others into the uterus (e.g., horse), so…
clock | May 4, 2008Waste no more time arguing about what a good man should be. Be one.
- Marcus Aurelius
clock | May 4, 2008
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 opening of the ion channels during the action potential, the blood clotting cascade, emptying of the urinary bladder, copulation, breastfeeding and childbirth. The last two (and perhaps the last three!) involve the hormone oxytocin. The childbirth, at least in humans, is a canonical example and the standard story goes roughly like this:
When…
clock | May 4, 2008Grunewald station in Berlin is a small, unasuming train station that looks like thousands of such stations around the world. But it is at this spot that thousands of Jews were loaded onto trains to Auschwitz and other places, initially in precise batches of 100 people per day, later increasing to more than a thousand per day, some days skipped, some days seeing two trains off, most well documented, but some trains going off into unknown directions....
clock | May 4, 2008Memorial to the Murdered Jews of Europe where, by design, concrete slabs that are initially perfectly aligned, due to sinking of the soil, adopt all sorts of different angles. Looking down the "aisles", one sees people, children playing hide-and-seek, and suddenly disappearing. People vanish, while the entire structure slowly turns from perfect order to disorder:
clock | May 4, 2008The Boneyard XIX is up on Familiarity Breeds Content
Festival of the Trees #23 is up on 10000 birds
Circus of the Spineless #32 is up on Deep Sea News
Friday Ark #189 is up on Modulator
clock | May 4, 2008More pictures from the Museum:
We found a Coturnix:
Enormous insects:
Linnaeus, Ernst Mayr and Charles Darwin:
clock | May 4, 2008Catriona and I, obviously, had fun here:
Fossils, including the best Archaeopterix in the world:
The Evolution of Life:
clock | May 4, 2008Time to put up some of the pictures. Catriona took me around Berlin, for whatever one can see in just a day and a half - the Brandenburg gate, a slab of the Berlin wall, etc....
Quick breakfast:
Going from West to East Berlin:
The Wall:
The oldest traffic light in Germany:
Evening:
clock | May 4, 2008This post from March 27, 2006 starts with some of my old research and poses a new hypothesis.
The question of animal models
There are some very good reasons why much of biology is performed in just a handful of model organisms. Techniques get refined and the knowledge can grow incrementally until we can know quite a lot of nitty-gritty details about a lot of bioloigcal processes. One need not start from Square One with every new experiment with every new species. One should, of course, occasionally test how generalizable such findings are to other organisms, but the value of models is hard…
clock | May 3, 2008Sometimes the child in one behaves a certain way and the rest of oneself follows behind, slowly shaking its head.
- James E. Shapiro
clock | May 3, 2008Dog happy to see me. And others, of course. After 25.5 days, 4 countries, 5 airports, 8 flights by 5 airline companies, 2 panels, 2 lectures, 4 radio interviews, 2 newspaper interviews, 2 blogger meetups, and many good meals, I am mentally exhausted. Need to spend some time with the family. Offline. Feet up. Will see you all on Monday (may post the rest of Berlin pictures tomorrow, lazily).
clock | May 3, 2008Believe me, I love the word "circadian". It is a really cool word, invented by Franz Halberg in the late 1950s, out of 'circa' (Latin - "about") and diem ("a day"), to denote daily rhythms in biochemistry, physiology and behavior generated by the internal, endogenous biological clocks within living organisms.
It's been a while since the last time I found someone mistaking the word for 'cicada' which is a really cool insect. 'Circadian' has become quite common term in the media and, these days increasingly, in popular culture. Names of some bands contain the word. A few blogs' names…
clock | May 3, 2008This April 09, 2006 post places another paper of ours (Reference #17) within a broader context of physiology, behavior, ecology and evolution.
The paper was a result of a "communal" experiment in the lab, i.e., it was not included in anyone's Thesis. My advisor designed it and started the experiment with the first couple of birds. When I joined the lab, I did the experiment in an additional number of animals. When Chris joined the lab, he took over the project and did the rest of the lab work, including bringin in the idea for an additional experiment that was included, and some of the…
clock | May 2, 2008Gather ye rosebuds while ye may,
Old Times is still a-flying:
And this same flower that smiles today,
Tomorrow will be dying.
- Robert Herrick
clock | May 2, 2008You and I, as well as all of our mammalian brethren, have just a few photopigments, i.e., colored molecules that change shape when exposed to light and subsequently trigger cascades of biochemical reactions leading to changes in electrical properties of sensory neurons, which lead to modulation of neurotransmitter release, which propagates the information from one neuron to the next until it is integrated and interpreted somewhere in the brain - we see the light!
More under the fold....
Mammals have rhodopsin (in rod-shaped photoreceptor cells in the retina of the eye), three or four color-…
clock | May 2, 2008Hypotheses leading to more hypotheses (from March 19, 2006 - the Malaria Day):
I have written a little bit about malaria before, e.g, here and here, but this is my special Malaria Action Day post, inspired by a paper [1] that Tara sent me some weeks ago and I never got to write about it till now.
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In a journal called "Medical Hypotheses" Kumar and Sharma [1] propose that jet-lagged travellers may be more susceptible to getting infected with malaria. They write:
Rapid travel across several time zones leads to…
clock | May 1, 2008See, the problem is that God gives men a brain and a penis, and only enough blood to run one at a time.
- Robin Williams
clock | May 1, 2008
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 new paper that combines both of those themes very nicely, but I'll start with a little bit of background first.
Daily Rhythms in Sensory Sensitivity
If almost every biochemical, physiological and behavioral function exhibits daily cycles, it is no surprise that such rhythms have been discovered in sensory sensitivity of many sensory modalities -…
clock | May 1, 2008Tangled Bank #104 is up on Dammit Jim!
Grand Rounds Vol. 4 No. 32 are up on Doc Gurley
I and the Bird #74 is up on Consworld
Change of Shift: Volume 2, Number 22 is up on Life in the NHS
The Carnival of Space - the anniversary edition - is up on Why Homeschool
Carnival of Education #169 is up on What It's Like on the Inside
The 122nd Carnival of Homeschooling is up on HomeschoolBuzz