Biology posts
- April 27, 2009
- 09:35 AM
- 1,241 views
On immunology and malaria
by iayork in Mystery Rays from Outer Space
Life cycle of Plasmodium falciparu
“In this article we have attempted to make the case that we may not know enough about malaria to make an effective vaccine. If we agree that the development of a malaria vaccine would profit from a better understanding of the basic immunology of the human response to malaria, we then [...]... Read more »
Pierce, S., & Miller, L. (2009) World Malaria Day 2009: What Malaria Knows about the Immune System That Immunologists Still Do Not. The Journal of Immunology, 182(9), 5171-5177. DOI: 10.4049/jimmunol.0804153
- April 27, 2009
- 09:28 AM
- 1,170 views
More Brain Voodoo, and This Time, It's Not Just fMRI
by Neuroskeptic in Neuroskeptic
Ed Vul et al recently created a splash with their paper, Puzzlingly high correlations in fMRI studies of emotion, personality and social cognition (better known by its previous title, Voodoo Correlations in Social Neuroscience.) Vul et al accused a large proportion of the published studies in a certain field of neuroimaging of committing a statistical mistake. The problem, which they call the "non-independence error", may well have made the results of these experiments seem much more impressive than they should have been. Although there was no suggestion that the error was anything other than an honest mistake, the accusations still sparked a heated and ongoing debate. I did my best to explain the issue in layman's terms in a previous post.Now, like the aftershock following an earthquake, a second paper has appeared, from a different set of authors, making essentially the same accusations. But this time, they've cast their net even more widely. Vul et al focused on only a small sub-set of experiments using fMRI to examine correlations between brain activity and personality traits. But they implied that the problem went far beyond this niche field. The new paper extends the argument to encompass papers from across much of modern neuroscience.The article, Circular analysis in systems neuroscience: the dangers of double dipping, appears in the extremely prestigious Nature Neuroscience journal. The lead author, Dr. Nikolaus Kriegeskorte, is a postdoc in the Section on Functional Imaging Methods at the National Institutes of Health (NIH).Kriegeskorte et al's essential point is the same as Vul et al's. They call the error in question "circular analysis" or "double-dipping", but it is the same thing as Vul et al's "non-independent analysis". As they put it, the error could occur wheneverdata are first analyzed to select a subset and then the subset is reanalyzed to obtain the results.and it will be a problem whenever the selection criteria in the first step are not independent of the reanalysis criteria in the second step. If the two sets of criteria are independent, there is no problem.Suppose that I have some eggs. I want to know whether any of the eggs are rotten. So I put all the eggs in some water, because I know that rotten eggs float. Some of the eggs do float, so I suspect that they're rotten. But then I decide that I also want to know the average weight of my eggs . So I take a handful of eggs within easy reach - the ones that happen to be floating - and weigh them.Obviously, I've made a mistake. I've selected the eggs that weigh the least (the rotten ones) and then weighed them. They're not representative of all my eggs. Obviously, they will be lighter than the average. Obviously. But in the case of neuroscience data analysis, the same mistake may be much less obvious. And the worst thing about the error is that it makes data look better, i.e. more worth publishing:Distortions arising from selection tend to make results look more consistent with the selection criteria, which often reflect the hypothesis being tested. Circularity is therefore the error that beautifies results, rendering them more attractive to authors, reviewers and editors, and thus more competitive for publication. These implicit incentives may create a preference for circular practices so long as the community condones them.To try to establish how prevalent the error is, Kriegeskorte et al reviewed all of the 134 fMRI papers published in the highly regarded journals Science, Nature, Nature Neuroscience, Neuron and the Journal of Neuroscience during 2008. Of these, they say, 42% contained at least one non-independent analysis, and another 14% may have done. That leaves 44% which were definitely "clean". Unfortunately, unlike Vul et al who did a similar review, they don't list the "good" and the "bad" papers.They then go on to present the results of two simulated fMRI experiments in which seemingly exciting results emerge out of pure random noise, all because of the non-independence error. As they go on to point out, these are extreme cases - in real life situations, the error might only have a small impact. But the point, and it's an extremely important one, is that the error can creep in without being detected if you're not very careful. In both of their examples, the non-independence error is quite subtle and at first glance the methodology is fine. It's only on closer examination that the problem becomes apparent. The price of freedom from the error is eternal vigilance.But it would be wrong to think that this is a problem with fMRI alone, or even neuroimaging alone. Any neuroscience experiment in which a large amount of data is collected and only some of it makes it into the final analysis is equally at risk. For example, many neuroscientists use electrodes to record the electrical activity in the brain. It's increasingly common to use not just one electrode but a whole array of them to record activity from more than brain one cell at once. This is a very powerful technique, but it raises the risk the non-independence error, because there is a temptation to only analyze the data from those electrodes where there is the "right signal", as the author's point out:In single-cell recording, for example, it is common to select neurons according to some criterion (for example, visual responsiveness or selectivity) before applyingfurther analyses to the selected subset. If the selection is based on the same dataset as is used for selective analysis, biases will arise for any statistic not inherently independent of the selection criterion.In fact, Kriegeskorte et al praise fMRI for being, in some ways, rather good at avoiding the problem:To its great credit, neuroimaging has developed rigorous methods for statistical mapping from its beginning. Note that mapping the whole measurement volume avoids selection altogether; we can analyze and report results for all locations equally, while accounting for the multiple tests performed across locations..With any luck, the publication of this paper and Vul's so close together will force the neuroscience community to seriously confront this error and related statistical weaknesses in modern neuroscience data analysis. Neuroscience can only emerge stronger from the debate.Kriegeskorte, N., Simmons, W., Bellgowan, P., & Baker, C. (2009). Circular analysis in systems neuroscience: the dangers of double dipping Nature Neuroscience DOI: 10.1038/nn.2303... Read more »
Kriegeskorte, N., Simmons, W., Bellgowan, P., & Baker, C. (2009) Circular analysis in systems neuroscience: the dangers of double dipping. Nature Neuroscience. DOI: 10.1038/nn.2303
- April 27, 2009
- 09:00 AM
- 1,189 views
Swine flu returns
by vrr in virology blog
A novel strain of H1N1 swine influenza virus has now also been isolated from cases of respiratory disease in Mexico City, New York City, and two locations in Canada. Clearly I was wrong in hypothesizing that the five mild cases in Texas and California reported last week were not a cause for alarm.
In Mexico City [...]... Read more »
Van Reeth, K, & Nicoll, A. (2009) A human case of swine influenza virus infection in Europe - Implications for human health and research. Eurosurveillance, 14(7), 19124-19125. DOI: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId
- April 27, 2009
- 05:00 AM
- 894 views
Aphids, apples and evolution
by Jeremy in Agricultural Biodiversity Weblog
Wild relatives and field genebanks of apples have helped to answer a long-standing puzzle: why do leaves turn red in autumn.... Read more »
Archetti, M. (2009) Evidence from the domestication of apple for the maintenance of autumn colours by coevolution. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2009.0355
- April 26, 2009
- 05:03 PM
- 1,545 views
How do I name thee?
by stajich in The Hyphal Tip
In a letter to the editor to the journal Nature, regarding the recently discovered/induced sexual stage in Aspergillus fumigatus, David Hawksworth argues that using the separate names for sexual (teleomorph) and asexual (anamorph) stages is confusing and unnecessary in this context. The name Neosartorya fumigata is given to the sexual stage which was produced from two [...]... Read more »
Hawksworth, D. (2009) Separate name for fungus's sexual stage may cause confusion. Nature, 458(7234), 29-29. DOI: 10.1038/458029c
- April 26, 2009
- 02:00 PM
- 1,953 views
Making new heart cells
by Ed Yong in Not Exactly Rocket Science
It is literally very difficult to mend a broken heart. Despite its importance, the heart is notoriously bad at regenerating itself after injury. If it is damaged - say, by a heart attack - it replaces the lost muscle with scar tissue rather than fresh cells. That weakens it and increases the chance of heart failure later on in life. No wonder that heart disease is the western world's leading cause of death and illness.
If that picture seems bleak, two teams of scientists have some heartening news for you. The first has found that the heart does actually have the ability to renew its cells, albeit to a limited degree. And the second group has discovered a cocktail of proteins can nudge this process along, at least in mice.
Taking heart
The heart is made of an exclusive breed of cells called cardiomyocytes, whose synchronised contractions provide the heart with its beat. The cardiomyocytes develop from a more basic layer of cells called the mesoderm, which also gives rise to bones, cartilage and other tissues. Now, Jun Takeuchi and Benoit Bruneau from the Gladstone Institute of Cardiovascular Disease have found that a cocktail of three proteins - Gata4, Tbx5 and Baf60c - are enough to transform mesodermal cells into beating cardiomyocytes.
All three are needed for the job. Together, they managed to switch on the full gamut of genes needed to program the mesoderm of embryonic mice into heart cells. When they were added, Takeuchi and Bruneau found signs of various proteins that are associated with developing embryonic hearts, even in parts of the mesoderm that would normally not turn into heart muscle. These out-of-place cells developed very quickly too, for they started beating before the mice's own heart cells did.
That's a massive achievement and one that's completely unprecedented for mammals. Other groups have tried to use protein combos to produce cardiomyocytes in other species, but with little success. In chicks, certain combinations switched on genes involved in heart development, but never went the whole way. In frogs or zebrafish, which have simpler hearts, two proteins were used to produce heart cells, but with just a one in ten success rate. Takeuchi and Bruneau managed to do the same in 9 out of 11 mouse embryos.
Read the rest of this post... | Read the comments on this post...... Read more »
Bergmann, O., Bhardwaj, R., Bernard, S., Zdunek, S., Barnabe-Heider, F., Walsh, S., Zupicich, J., Alkass, K., Buchholz, B., Druid, H.... (2009) Evidence for Cardiomyocyte Renewal in Humans. Science, 324(5923), 98-102. DOI: 10.1126/science.1164680
- April 26, 2009
- 09:12 AM
- 1,419 views
A four-column theory for the origin of the triplet code
by Abhishek Tiwari in Fisheye Perspective
In a latest Biology Direct paper Paul G Higgs proposed a 'four-column' theory for the origin of the genetic code. Theory suggest that subdivision of codon blocks gave rise to an optimized code. Unlike previously proposed coevolution theory where genetic code evolution predicted are usually not favored by selection, in 'four-column' theory major driving force during code evolution process is positive selection which maintain increased diversity and functionality of the proteins, minimization of translational error appears to be only a secondary factor although current code is fully optimized with respect to translational error. Further this theory suggests that(i) The earliest amino acids in the code were those that are easiest to synthesize non-biologically, namely Gly, Ala, Asp, Glu and Val. (ii) These amino acids are assigned to codons with G at first position. Therefore the first code may have used only these codons. (iii) The code rapidly developed into a four-column code where all codons in the same column coded for the same amino acid: NUN = Val, NCN = Ala, NAN = Asp and/or Glu, and NGN = Gly. (iv) Later amino acids were added sequentially to the code by a process of subdivision of codon blocks in which a subset of the codons assigned to an early amino acid were reassigned to a later amino acid. (v) Later amino acids were added into positions formerly occupied by amino acids with similar properties because this can occur with minimal disruption to the proteins already encoded by the earlier code. As a result, the properties of the amino acids in the final code retain a four-column pattern that is a relic of the earliest stages of code evolution.Proposed four-column structure of the earliest genetic codePossible evolution of the four-column code via subdivision of codon blocksUsing a cost function and a barrier function, theory predicts that that new amino acids can be added into positions previously occupied by amino acids with similar properties. This is because, when amino acids are added in this way, there is minimal disruption to the protein sequences that had already evolved under the previous code.Reference:Higgs, P. (2009). A four-column theory for the origin of the genetic code: tracing the evolutionary pathways that gave rise to an optimized code Biology Direct, 4 (1) DOI: 10.1186/1745-6150-4-16... Read more »
Higgs, P. (2009) A four-column theory for the origin of the genetic code: tracing the evolutionary pathways that gave rise to an optimized code. Biology Direct, 4(1), 16. DOI: 10.1186/1745-6150-4-16
- April 26, 2009
- 12:30 AM
- 834 views
How Discriminating Ants Choose
by Johnny in Ecographica
In addition to merging sci-fi art with the reality of science ('tagged ant' image below), researchers at the School of Biological Sciences within the University of Bristol have demonstrated that the ‘irrationality’ associated with contextual decision making is avoided in the ant Temnothorax albipennis as it chooses between alternative nesting sites.
... Read more »
Robinson, E., Smith, F., Sullivan, K., & Franks, N. (2009) Do ants make direct comparisons?. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2009.0350
- April 25, 2009
- 12:24 AM
- 837 views
Resilience in Acropora Corals
by Johnny in Ecographica
Great news - local management of water quality and other factors may significantly contribute to the survivability of coral reefs that have been negatively impacted by climate change.
A massive bleaching event took place on the Great Barrier Reef approximately three years ago and devastated a huge number of inshore reefs, but the corals made an unprecedented comeback – in only a year’s time!
... Read more »
Diaz-Pulido, G., McCook, L., Dove, S., Berkelmans, R., Roff, G., Kline, D., Weeks, S., Evans, R., Williamson, D., & Hoegh-Guldberg, O. (2009) Doom and Boom on a Resilient Reef: Climate Change, Algal Overgrowth and Coral Recovery. PLoS ONE, 4(4). DOI: 10.1371/journal.pone.0005239
- April 24, 2009
- 02:58 PM
- 1,294 views
snails going nom nom nom = productive diverse tidepools?
by jebyrnes in I'm a chordata, urochordata!
The “gold standard” experimental design for asking how do changes in biodiversity change ecosystem function has been to randomly assemble communities of varying species richness, but equal abundance, and examining differences in function from one level of richness to the next.
But let’s be honest. Changes in diversity due to impacts by man will not [...]... Read more »
Altieri, A., Trussell, G., Ewanchuk, P., Bernatchez, G., & Bracken, M. (2009) Consumers Control Diversity and Functioning of a Natural Marine Ecosystem. PLoS ONE, 4(4). DOI: 10.1371/journal.pone.0005291
- April 24, 2009
- 01:22 PM
- 658 views
Stickleblog: What happens when you put a stickleback and a trout together?
by Sticklematt in Wainwright Lab
One of the most striking features of marine stickleback is the row of bony armor plates that run along the side of the body. These "armor plates" are actually enlarged and ossified lateral line scales, and they're a unique feature of threespine stickleback; other sticklebacks (and tubesnouts) just have a tiny row of lateral scales at the most.Threespine stickleback, fully armored form(illustration from Wikimedia Commons)Freshwater stickleback populations will often have few to no armor plates, which has prompted biologists to look into the both the genetic basis of armor loss and the effect of natural selection on plate number.In 1992, Canadian ecologist Tom Reimchen published a paper in Evolution that shed some light on the latter question.Tom captured wild stickleback from a freshwater lake and then put them in an enclosure with one of their chief lake predators, the cutthroat trout. Predictably, the trout would bite the stickleback and try to eat it; whenever a bitten stickleback escaped or was spit out, Tom caught it. The first 153 fish were simply preserved, and the last 143 fish were placed in aquariums and monitored for several days to see if their injuries were fatal.Then, Tom took a look at what sort of injuries all 296 stickleback had sustained from the trout attack. In particular, were stickleback with more armor plates injured less frequently than stickleback with fewer plates? It turned out that puncture wounds from trout teeth were significantly less common in more armored stickleback.Top graph: plate number versus puncture wounds sustainedBottom graph: plate number versus survivalIn the second group of 143 fish that had been monitored for survival, over half of the fish died, many of whom did not survive the first 24 hours (for those wondering, Tom did have a control tanks of non-injured fish in the same room - they all survived). Fish with more plates survived significantly longer than fish with fewer plates; in addition, fish with injuries exhibited significantly lower survival.Taken together, the results suggest that having more armor plates results in fewer injuries sustained from predators, which increases the fish's chances of survival if it escapes being eaten.There is one interesting caveat, though: all of these fish would still qualify as "low-plated" freshwater stickleback. Most of the plate variation involved the presence of a few additional plates closer to the head - does this mean that fully-plated marine fish get the same sort of protective benefit from having armor closer to the tail?Reimchen, T. (1992). Injuries on Stickleback from Attacks by a Toothed Predator (Oncorhynchus) and Implications for the Evolution of Lateral Plates Evolution, 46 (4) DOI: 10.2307/2409768... Read more »
Reimchen, T. (1992) Injuries on Stickleback from Attacks by a Toothed Predator (Oncorhynchus) and Implications for the Evolution of Lateral Plates. Evolution, 46(4), 1224. DOI: 10.2307/2409768
- April 24, 2009
- 01:17 PM
- 1,499 views
A Fossilized Shark Bite (NOM NOM NOM)
About four million years ago, in the shallows of an ocean that once covered what is now southern Peru, a large shark bit into the jaw of a baleen whale. The whale had been dead for some time, but it was kept afloat but the gases building up in its body as it decomposed. It was absolutely rotten, but it still presented a free meal to the scavenging shark. As the shark bit down, however, one of its teeth became stuck in the whale's jaw bone and broke off. No matter. The lost tooth would soon be replaced by another.
The above scenario does involve a bit of speculation, but such events certainly did happen. Sharks fed on whale carcasses in ancient times just like they do today, and when sharks feed they often lose teeth. In the latest edition of the journal PALAIOS scientists Dana Ehret, Bruce MacFadden, and Rodolfo Salas- Gismondi describe a 4-5 million year old piece of whale jaw with a shark tooth stuck in it, direct evidence of interaction between predator and prey.
The fossil that is the subject of the study was discovered in 2007 from the Pisco Formation in Peru. It is a site well-known for its excellent preservation of fossils, enough to put together a fairly clear picture of what the area was once like. Around 4-5 million years ago the site was a shallow, coastal environment inhabited by turtles, crocodiles, fish, sharks, whales, and even a giant aquatic sloth. Of the shark species present there some got to be quite large; the older part of the Pisco Formation contains the remains of Carcharocles megalodon and Isurus hastalis while the younger part contains the fossils of a species of Carcharodon (the genus to which the living great white shark belongs).
The tooth crown of Carcharodon broken off in a baleen whale jaw. The boxes on the side indicate the presence of tooth scrapes. From Ehret, et al 2009.
The tooth that was broken off in the whale jaw most closely resembles that of Carcharodon, and this is supported by comparing it to a complete set of jaws from the same locality just described in the Journal of Vertebrate Paleontology. The question is, however, whether the whale was killed by the shark or already dead when the Carcharodon came along. It is not an easy question to answer, but there are ways to rule out some of the possibilities.
If the shark had attacked but the whale survived it would be expected that the whale bone would show signs of healing. No such signs were found. This leaves two main possibilities: that the shark killed the whale or the shark scavenged the whale carcass. The latter hypothesis seems more likely. Observations of sharks, even large ones, attacking living baleen whales are extremely rare, and when they do attack they often target the belly or sides of the whale. More often sharks are seen feeding on the decomposing carcasses of whales which often float on the surface of the ocean for extended periods of time. During these feeding events the postcranial part of the whale is often preferentially stripped of blubber and meat, but on at least one occasion juvenile great white sharks were seen to feed around the head region of a dead baleen whale. Perhaps the fossil from Peru is a remnant of a similar behavior.
Unfortunately the paper does not have much of a satisfying conclusion. The fossil probably represents a scavenging event but it is not possible to know for sure (unless, of course, you have a time machine, some scuba gear, and about a million years to kill). Perhaps the specimen is not as exciting as some other recently announced fossils but it is interesting for another reason. It is a specimen that illustrates an interaction between two organisms, a little piece of paleobiology frozen in time.
DANA J. EHRET, BRUCE J. MACFADDEN, and RODOLFO SALAS-GISMONDI (2009). CAUGHT IN THE ACT: TROPHIC INTERACTIONS BETWEEN A 4-MILLION-YEAR-OLD WHITE
SHARK (CARCHARODON) AND MYSTICETE WHALE FROM PERU PALAIOS, 24, 329-333 DOI: 10.2110/palo.2008.p08-077r Read the comments on this post...... Read more »
DANA J. EHRET, BRUCE J. MACFADDEN, and RODOLFO SALAS-GISMONDI. (2009) CAUGHT IN THE ACT: TROPHIC INTERACTIONS BETWEEN A 4-MILLION-YEAR-OLD WHITE SHARK (CARCHARODON) AND MYSTICETE WHALE FROM PERU. PALAIOS, 329-333. DOI: 10.2110/palo.2008.p08-077r
- April 24, 2009
- 12:49 PM
- 1,146 views
Science Technology F*ing Rocks!
by Christie Wilcox in Observations of a Nerd
First, the visual:
image creditOk. Now to explain.
Scientists from the University of Bristol Woodland Road wanted to learn more about rock ants (Temnothorax albipennis). Specifically, they had noticed that the ants seem to be able to pick out the best possible nest sites when they decide to move. As a collective group, the entire colony chooses where to settle in, though scouts fan out and look around to see what's available. At first, they thought that the ants just directly compared options. But ants that never see the worse sites still help the colony decide on the better one - and...
There's more... go to my site to read the rest!... Read more »
Robinson, E., Smith, F., Sullivan, K., & Franks, N. (2009) Do ants make direct comparisons?. Proceedings of the Royal Society B: Biological Sciences. DOI: 10.1098/rspb.2009.0350
- April 24, 2009
- 12:31 PM
- 721 views
Female birds stop singing when they move north
by Jeremy Yoder in Denim and Tweed
A study in this week's Proceedings of the Royal Society B suggests that the sexually dimorphic pattern of birdsong we're used to in temperate latitudes -- with males singing elaborately and females usually not -- evolves because female birds stop singing when their species move to more northerly latitudes [$-a]. Why this is, however, remains an open question.
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Photo by Vicki & Chuck Rogers.The study's authors reconstruct the evolution of home range (temperate versus tropical) and sexual song dimorphism (both sexes singing versus only males singing) in the New World blackbirds, the family that includes orioles, cowbirds, and red-winged blackbirds (pictured). The reconstruction reveals a strongly significant association between the evolution of male-only singing and transitions from tropical to temperate breeding ranges. The authors discuss this transition in a few key groups, including North American red-winged blackbirds (Agelaius phoeniceus) and their sister species, the Cuban red-shouldered blackbird (A. assimilis):Females of A. assimilis are nearly indistinguishable from conspecific males in song structure and song rate and are also similar in plumage and body size ... whereas females of A. phoeniceus differ considerably from conspeicific males in these traits .... it is clear that the changes in female song and plumage must have occurred quite rapidly. [In-text citations omitted.]As clear as the observed pattern is, however, there doesn't seem to be a good general explanation for it. The authors point to cases where female singing is lost within tropical-breeding lineages, which might help disentangle the effects of latitude and other evolutionary forces generating the observed pattern. In these cases, loss of female song is associated with colonial nesting and polygynous breeding, whereas singing by both sexes is associated with year-round pairing.
The temperate-breeding blackbirds tend to be migratory, with males often arriving at the breeding range ahead of females to establish nest sites and territories. In these cases singing by the males serves to attract females and to announce ownership of territory. Could that migration-induced division of labor lead females to give up singing? I'm just an amateur birder, but it sounds plausible to me.
Reference
Price, J., Lanyon, S., & Omland, K. (2009). Losses of female song with changes from tropical to temperate breeding in the New World blackbirds Proceedings of the Royal Society B: Biological Sciences, 276 (1664), 1971-80 DOI: 10.1098/rspb.2008.1626... Read more »
Price, J., Lanyon, S., & Omland, K. (2009) Losses of female song with changes from tropical to temperate breeding in the New World blackbirds. Proceedings of the Royal Society B: Biological Sciences, 276(1664), 1971-80. DOI: 10.1098/rspb.2008.1626
- April 24, 2009
- 10:53 AM
- 1,170 views
Dietary Overlap Increases Extinction Risk
by Allie Wilkinson in OH, FOR THE LOVE OF SCIENCE!
Imagine you’re sitting down to a family dinner with your siblings, you’re a vegetarian, and your older, bigger, bullying brother just won the fight for the mashed potatoes and ate the last of them, and now the only thing left on the dining table is chicken. Sure you could eat chicken, but it would [...]... Read more »
Hayward, M., & Kerley, G. (2008) Prey preferences and dietary overlap amongst Africa's large predators. South African Journal of Wildlife Research, 38(2), 93-108. DOI: 10.3957/0379-4369-38.2.93
- April 24, 2009
- 10:45 AM
- 1,539 views
Night owls - the energizer bunnies of society
by Christie Wilcox in Observations of a Nerd
I have to start work at 8 am every morning. I'm not sure exactly who decided that scientists should start early, but it seems to be a universal assumption. Throughout college my science classes were always first thing, and research efforts often seem to involve early morning work. But I've never really been a morning person. Last night is a great example: I had to clean up the house in preparation for Barry's brother coming to stay with us (which, with a dog and a cat and two messy people, is no small feat). We started when we got home and tackled room after room. As I looked up at the clock...
There's more... go to my site to read the rest!... Read more »
Schmidt, C., Collette, F., Leclercq, Y., Sterpenich, V., Vandewalle, G., Berthomier, P., Berthomier, C., Phillips, C., Tinguely, G., Darsaud, A.... (2009) Homeostatic Sleep Pressure and Responses to Sustained Attention in the Suprachiasmatic Area. Science, 324(5926), 516-519. DOI: 10.1126/science.1167337
- April 24, 2009
- 10:27 AM
- 1,059 views
The silent force in the food web
by Katie Kline in EcoTone
Addition of parasites (red spheres) visibly increases connectivity of species in this representation of an Arctic food web.
Studies of food webs fascinate community ecologists. There seems to be a never-ending supply of interactions to observe, analyze and use in predictions. From the largest apex predators, feeding once a week, to the smallest alga, constantly [...]... Read more »
Amundsen, P., Lafferty, K., Knudsen, R., Primicerio, R., Klemetsen, A., & Kuris, A. (2009) Food web topology and parasites in the pelagic zone of a subarctic lake. Journal of Animal Ecology, 78(3), 563-572. DOI: 10.1111/j.1365-2656.2008.01518.x
Beckerman, A., & Petchey, O. (2009) Infectious food webs. Journal of Animal Ecology, 78(3), 493-496. DOI: 10.1111/j.1365-2656.2009.01538.x
- April 24, 2009
- 09:00 AM
- 1,393 views
New swine influenza viruses in humans
by vrr in virology blog
A new strain of swine influenza virus has been recently isolated from seven persons in the US. Is it time to break out the swine flu vaccine of 1976?
Last week the CDC reported that swine influenza virus had been isolated from two children with respiratory illness in California. The cases were not linked and the [...]... Read more »
Weingartl, H., Albrecht, R., Lager, K., Babiuk, S., Marszal, P., Neufeld, J., Embury-Hyatt, C., Lekcharoensuk, P., Tumpey, T., Garcia-Sastre, A.... (2009) Experimental Infection of Pigs with the Human 1918 Pandemic Influenza Virus. Journal of Virology, 83(9), 4287-4296. DOI: 10.1128/JVI.02399-08
de Jong, J., Smith, D., Lapedes, A., Donatelli, I., Campitelli, L., Barigazzi, G., Van Reeth, K., Jones, T., Rimmelzwaan, G., Osterhaus, A.... (2007) Antigenic and Genetic Evolution of Swine Influenza A (H3N2) Viruses in Europe. Journal of Virology, 81(8), 4315-4322. DOI: 10.1128/JVI.02458-06
Van Reeth, K. (2007) Avian and swine influenza viruses: our current understanding of the zoonotic risk. Veterinary Research, 38(2), 243-260. DOI: 10.1051/vetres:2006062
- April 23, 2009
- 10:00 AM
- 1,519 views
Gigantothermy: Size Matters
by Peter Etnoyer in Deep Sea News
by Bryan Wallace for Deep Sea News
When you think of cold marine environments, you probably think of blubber-wrapped seals, whales, and walruses, big, furry bears, or a huddled mass of penguins. What do those animals have in common? They are endotherms, their body temperature maintenance depends on consistently high levels of heat generated (and retained) [...]... Read more »
WALLACE, B., & JONES, T. (2008) What makes marine turtles go: A review of metabolic rates and their consequences. Journal of Experimental Marine Biology and Ecology. DOI: 10.1016/j.jembe.2007.12.023
- April 23, 2009
- 09:00 AM
- 1,162 views
Could Rift Valley fever come to the US?
by vrr in virology blog
In an NYTimes Op-Ed article called “The Scary Caterpillar”, Jeffrey Lockwood wrote about potential use of a virus as a weapon of bioterrorism:
What if a terrorist group announced that their operatives had introduced Rift Valley fever into the United States? This mosquito-borne disease would make West Nile virus look like a case of the sniffles. [...]... Read more »
Moutailler, S., Krida, G., Schaffner, F., Vazeille, M., & Failloux, A. (2008) Potential Vectors of Rift Valley Fever Virus in the Mediterranean Region. Vector-Borne and Zoonotic Diseases, 8(6), 749-754. DOI: 10.1089/vbz.2008.0009
Turell, M., Dohm, D., Mores, C., Terracina, L., Wallette, D., Hribar, L., Pecor, J., & Blow, J. (2008) Potential for North American Mosquitoes to Transmit Rift Valley Fever Virus . Journal of the American Mosquito Control Association, 24(4), 502-507. DOI: 10.2987/08-5791.1
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