Monday night - time to check out the new articles in PLoS Biology and PLoS Medicine:
Everybody knows that sleep is important, yet the function of sleep seems like the mythological phoenix: "Che vi sia ciascun lo dice, dove sia nessun lo sa" ("that there is one they all say, where it may be no one knows," Wolfgang Amadeus Mozart and Lorenzo da Ponte [1790], Così fan tutte). But what if the search for an essential function of sleep is misguided? What if sleep is not required but rather a kind of extreme indolence that animals indulge in when they have no more pressing needs, such as eating or reproducing? In many circumstances sleeping may be a less dangerous choice than roaming around, wasting energy and exposing oneself to predators. Also, if sleep is just one out of a repertoire of available behaviors that is useful without being essential, it is easier to explain why sleep duration varies so much across species [1-4]. This "null hypothesis" [5-7] would explain why nobody has yet identified a core function of sleep. But how strong is the evidence supporting it? And are there counterexamples?
SciCurious reviews this article as well.
Whisker-Mediated Texture Discrimination:
Our sense of touch provides information about nearby objects that can affect us in an immediate way. Texture, a central component of touch, is sensed quickly, even before an object is explored to measure its size, shape, or identity. To learn how contact with a surface produces a sensation of texture, many laboratories have examined the whisker system of rodents. Touch sensed through the whiskers in rodents works differently than touch sensed through the fingertips in primates. Touch receptors in the fingertips are distributed in a continuous sheet; this spatial distribution of inputs gives important signals about texture [1]. In contrast, rodents use a set of roughly 30 whiskers on each side of the snout, palpating surfaces through a 5-15 Hz forward-backward motion known as "whisking." When a whisker's tip or shaft makes contact with a texture, its movement changes; whisker motion signals report to the brain what the whiskers have contacted.
Where Does Bluetongue Virus Sleep in the Winter?:
Bluetongue virus (BTV) is spread by the bites of Culicoides midges (Figure 1), and can infect ruminant livestock such as cattle, sheep, and goats, wild ruminants such as deer, and camelids. Some infected animals develop the disease known as bluetongue, with clinical signs ranging from apathy and weight loss to swollen heads, tender feet and death (Figure 2). Historically a tropical and subtropical disease, bluetongue has become a regular visitor to southern Europe in the last decade [1,2]. Although growth in the global trade in livestock may have increased the frequency with which exotic viruses are introduced into Europe, the increasing tendency of those introduced strains to persist and spread is probably best explained by changes to the European climate [3], and several direct and indirect links between climate and BTV transmission have been identified [2]. BTV reached northern Europe for the first time in 2006, and affected around 2,000 holdings before reports ceased in early January 2007. The outbreak then re-emerged months later [4] and spread to a further 45,000 holdings by the end of the year, making it the most economically damaging outbreak of bluetongue ever seen [2,5].
SAW: Breaking Down Barriers between Art and Science:
The path to specialization of knowledge starts early. By the time children leave primary school, they have already been taught to view subjects like biology, art, and social studies as unrelated disciplines rather than as interlocking pieces that together lay the foundation for a deeper understanding of the world. The divisions between science, the arts, and the humanities are reinforced in high school, where each subject is taught by a different instructor under pressure to "teach to the test," a practice that further isolates subjects, stifles inquisitiveness, and quells creativity. By the time we become specialists as adults, our ability to recognize connections between disciplines tends to diminish even further--often at a price. If during this process, we lose the ability to communicate with other groups of specialists (for example, chemists, physicists, and mathematical modelers) or with those who have not had any formal science education beyond high school (which would include many taxpayers, politicians, and policy makers), if we become unresponsive to the needs of society, then our value to society becomes compromised. And the question arises: how do we break down these barriers or prevent them from becoming established in the first place, without compromising the standards of the different disciplines?
Effect of the California Tobacco Control Program on Personal Health Care Expenditures:
Large state tobacco control programs have been shown to reduce smoking and would be expected to affect health care costs. We investigate the effect of California's large-scale tobacco control program on aggregate personal health care expenditures in the state. Cointegrating regressions were used to predict (1) the difference in per capita cigarette consumption between California and 38 control states as a function of the difference in cumulative expenditures of the California and control state tobacco control programs, and (2) the relationship between the difference in cigarette consumption and the difference in per capita personal health expenditures between the control states and California between 1980 and 2004. Between 1989 (when it started) and 2004, the California program was associated with $86 billion (2004 US dollars) (95% confidence interval [CI] $28 billion to $151 billion) lower health care expenditures than would have been expected without the program. This reduction grew over time, reaching 7.3% (95% CI 2.7%-12.1%) of total health care expenditures in 2004. A strong tobacco control program is not only associated with reduced smoking, but also with reductions in health care expenditures.
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