Supersymmetric Baryonic Branes

We derive an energy bound for a `baryonic' D5-brane probe in the $adS_5\times S^5$ background near the horizon of $N$ D3-branes. Configurations saturating the bound are shown to be 1/4 supersymmetric $S^5$-wrapped D5-branes, with a total Born-Infeld charge $N$. Previous results are recovered as a special case. We derive a similar energy bound for a `baryonic' M5-brane probe in the background of $N$ M5-branes. Configurations saturating the bound are again 1/4 supersymmetric and, in the $adS_7\times S^4$ near-horizon limit, provide a worldvolume realization of the `baryon string' vertex of the (2,0)-supersymmetric six-dimensional conformal field theory on coincident M5-branes. For the full M5-background we find a worldvolume realization of the Hanany-Witten effect in M-theory.Comment: 32 pp. Third version is the same as the second except for a little additional material. To appear in JHE

"Who receives statins? Variations in physicians’ prescribing patterns for patients with coronary heart disease, dyslipidemia, and diabetes"

Our objective is to estimate the extent to which clinical and non-clinical factors are associated with physicians’ prescribing patterns for statins. The data are from the National Ambulatory Medical Care Survey for the period 1992 through 2004. The three samples examined included more than 14,000 patients who were diagnosed with coronary heart disease, high cholesterol, or diabetes, individuals who are most likely to benefit from being prescribed a statin drug. Using a multinomial logit framework, we find disparities in prescribing patterns based on non-clinical factors. Namely, whites and patients who have private insurance are more likely to be prescribed a statin than nonwhites and those with public insurance. Also, even though a large increase occurred in the uptake of statins over the period 1992 to 2004, our results for 2004 show that only about 50 percent of patients diagnosed with coronary heart disease were prescribed a statin. Because coronary heart disease is the leading cause of death in the U.S. and currently is estimated to cost over $150 billion annually in the U.S. in direct and indirect costs, observed differences in prescribing patterns along these dimensions is troubling and should be part of discussions dealing with health care reform.Pharmaceuticals; Statins; Equity in Physician Prescribing Patterns; Insurance

Call combinations in great apes and the evolution of syntax

Following the observation that vervet monkeys are capable of labelling different predator types with their vocalizations, comparative research in language evolution gained increasing interest. Over the last four decades, an impressive body of data has since accumulated demonstrating that many features of language can be found in the communication systems of nonhuman primates. One stumbling block to the phylogenetic reconstruction of language, however, has been language’s syntactic layer. We specifically highlight that, whilst current studies provide promising evidence for syntactic-like structures in the communication systems of monkeys, reconstructing the evolutionary origins of syntax hinges on comparable data from our closest-living relatives, the great apes. We critically assess existing data on potential candidates for combinatorial structures in the great ape clade and conclude that further experimental investigation is crucial to validating preliminary observational findings

All clear? Meerkats attend to contextual information in close calls to coordinate vigilance

Socio-demographic factors, such as group size and their effect on predation vulnerability, have, in addition to intrinsic factors, dominated as explanations when attempting to understand animal vigilance behaviour. It is generally assumed that animals evaluate these external factors visually; however, many socially foraging species adopt a foraging technique that directly compromises the visual system. In these instances, such species may instead rely more on the acoustical medium to assess their relative risk and guide their subsequent anti-predator behaviour. We addressed this question in the socially foraging meerkat (Suricata suricatta). Meerkats forage with their head down, but at the same time frequently produce close calls (‘Foraging' close calls). Close calls are also produced just after an individual has briefly scanned the surrounding environment for predators (‘Guarding' close calls). Here, we firstly show that these Guarding and Foraging close call variants are in fact acoustically distinct and secondly subjects are less vigilant (in terms of frequency and time) when exposed to Guarding close call playbacks than when they hear Foraging close calls. We argue that this is the first evidence for socially foraging animals using the information encoded within calls, the main adaptive function of which is unrelated to immediate predator encounters, to coordinate their vigilance behaviour. In addition, these results provide new insights into the potential cognitive mechanisms underlying anti-predator behaviour and suggest meerkats may be capable of signalling to group members the ‘absence' of predatory threat. If we are to fully understand the complexities underlying the coordination of animal anti-predator behaviour, we encourage future studies to take these additional auditory and cognitive dimensions into accoun

Copulation Calls in Female Chimpanzees ( Pan troglodytes schweinfurthii ) Convey Identity but Do Not Accurately Reflect Fertility

Copulation calls are a relatively common feature of female primate behavior thought to function in the advertisement of female receptivity and subsequent incitation of male-male competition. To date, the majority of work on copulation calling behavior has focused on various monkey species, with little empirical evidence from the great apes. Previous research on wild chimpanzees (Pan troglodytes schweinfurthii) has suggested that estrous females produce copulation calls to avoid monopolization by single males and to minimize competition from other females. We here extended these findings by investigating to what degree these social demands were reflected in the calls' acoustic structure. We recorded and acoustically analyzed 71 copulation call bouts from 6 adult female chimpanzees in the Budongo Forest, Uganda. We did not find any acoustic differences in calls given by females in fertile and nonfertile periods, as assessed by their hormonal profiles. However, the calls' acoustic structure did reliably encode identity cues of the calling female. We propose that, in chimpanzees, the use and morphology of copulation calls have jointly been shaped by the selective advantage of concealing fertility. Owing to the low visibility conditions associated with chimpanzees' natural forest habitat and their dispersed social system, providing identity cues may be of particular biological relevance for these nonhuman primate

Radial velocity variations of the pulsating subdwarf B star PG 1605+072

We present an analysis of high-speed spectroscopy of the pulsating subdwarf B star PG 1605+072. Periodic radial motions are detected at frequencies similar to those reported for photometric variations in the star, with amplitudes of up to 6 km/s. Differences between relative strengths for given frequency peaks for our velocity data and previously measured photometry are probably a result of shifting of power between modes over time. Small differences in the detected frequencies may also indicate mode-shifting. We report the detection of line-shape variations using the moments of the cross correlation function profiles. It may be possible to use the moments to identify the star's pulsation modes.Comment: 5 pages, 6 figure