Entropy and Temperature of Black 3-Branes

We consider slightly non-extremal black 3-branes of type IIB supergravity and show that their Bekenstein-Hawking entropy agrees, up to a mysterious factor, with an entropy derived by counting non-BPS excitations of the Dirichlet 3-brane. These excitations are described in terms of the statistical mechanics of a 3+1 dimensional gas of massless open string states. This is essentially the classic problem of blackbody radiation. The blackbody temperature is related to the temperature of the Hawking radiation. We also construct a solution of type IIB supergravity describing a 3-brane with a finite density of longitudinal momentum. For extremal momentum-carrying 3-branes the horizon area vanishes. This is in agreement with the fact that the BPS entropy of the momentum-carrying Dirichlet 3-branes is not an extensive quantity.Comment: 10 pages, LaTeX, minor revisions. v3: version that appeared in PR

Testing bulls for breeding soundness

New tests are available to ensure that bulls are fertile

Potential markets for a satellite-based mobile communications system

The objective of the study was to define the market needs for improved land mobile communications systems. Within the context of this objective, the following goals were set: (1) characterize the present mobile communications industry; (2) determine the market for an improved system for mobile communications; and (3) define the system requirements as seen from the potential customer's viewpoint. The scope of the study was defined by the following parameters: (1) markets were confined to U.S. and Canada; (2) range of operation generally exceeded 20 miles, but this was not restrictive; (3) the classes of potential users considered included all private sector users, and non-military public sector users; (4) the time span examined was 1975 to 1985; and (5) highly localized users were generally excluded - e.g., taxicabs, and local paging

Choosing a calcium supplement for sheep fed cereal grains

Sheep fed cereal grains as an energy source over summer usually need added calcium because cereal grains are generally low in calcium (for example, 0.03 per cent calcium compared to 0.26 per cent phosphorus), and there may not be a natural source such as clover, weeds, leafy stubble or edible bush in the paddock. The safestt and most effective calcium supplement is finely ground limestone added to the feed, but some farmers have used other sources of calcium such as gypsum and superphosphate in this manner

Black holes in asymptotically Lifshitz spacetimes with arbitrary critical exponent

Recently, a class of gravitational backgrounds in 3+1 dimensions have been proposed as holographic duals to a Lifshitz theory describing critical phenomena in 2+1 dimensions with critical exponent $z\geq 1$. We numerically explore black holes in these backgrounds for a range of values of $z$. We find drastically different behavior for $z>2$ and $z2$ ($z<2$) the Lifshitz fixed point is repulsive (attractive) when going to larger radial parameter $r$. For the repulsive $z>2$ backgrounds, we find a continuous family of black holes satisfying a finite energy condition. However, for $z<2$ we find that the finite energy condition is more restrictive, and we expect only a discrete set of black hole solutions, unless some unexpected cancellations occur. For all black holes, we plot temperature $T$ as a function of horizon radius $r_0$. For $z\lessapprox 1.761$ we find that this curve develops a negative slope for certain values of $r_0$ possibly indicating a thermodynamic instability.Comment: 23 pages, 6 figures, references corrected, graphs made readable in greyscal

Is dietary pattern of schizophrenia patients different from healthy subjects?

<p>Abstract</p> <p>Background</p> <p>There are limited findings about dietary patterns and food preferences among patients suffering from schizophrenia. The main objective of this study was therefore to compare the nutritional pattern of schizophrenia patients with that of matched healthy subjects.</p> <p>Methods</p> <p>The dietary pattern of 30 hospitalized 16–67 years old schizophrenic patients (11 female) was compared with that of 30 healthy age and sex matched individuals as control group. Subjects' anthropometric measurements including weight, height and body mass index (BMI), semi-quantitative food frequency (FFQ), medical and food history questionnaires were also collected and FFQs were then scored using Food Guide Pyramid to obtain the dietary scores. Percent body fat (%BF) was measured using bioelectrical impedance analysis (BIA) method.</p> <p>Results</p> <p>Female patients had more %BF and lower dietary pattern scores than that of their controls (32 ± 3.6 vs 27.7 ± 4.6 percent and 43.2 ± 11.9 vs 54.5 ± 10.7 points; respectively, p < 0.05 for both). They also consumed less milk and dairy products, fresh vegetables, fruits, chicken, and nuts compared with the female controls (p < 0.03). However, these patients used to eat more full-fat cream and carbonated drinks (p < 0.05). Male patients had lower BMI (22 ± 4.7 vs 25.6 ± 4.4; p < 0.05) than their counterpart controls but there was no significant difference between their %BFs. Moreover, they used to have more full-fat cream, hydrogenated fats, less red meat and nuts compared with the male controls (p < 0.05).</p> <p>Conclusion</p> <p>Schizophrenia patients have poor nutritional patterns. In particular, female patients have more percent body fat and lower dietary pattern scores compared with their healthy controls. All patients used to consume more fats and sweet drinks frequently. The findings of this study suggest that schizophrenia patients need specific medical nutrition therapies through limiting dietary fats and sugars intakes and weight control. Whether obesity is the consequence of disease, dietary preference or medications used remains to be cleared.</p

First Order Description of Black Holes in Moduli Space

We show that the second order field equations characterizing extremal solutions for spherically symmetric, stationary black holes are in fact implied by a system of first order equations given in terms of a prepotential W. This confirms and generalizes the results in [14]. Moreover we prove that the squared prepotential function shares the same properties of a c-function and that it interpolates between M^2_{ADM} and M^2_{BR}, the parameter of the near-horizon Bertotti-Robinson geometry. When the black holes are solutions of extended supergravities we are able to find an explicit expression for the prepotentials, valid at any radial distance from the horizon, which reproduces all the attractors of the four dimensional N>2 theories. Far from the horizon, however, for N-even our ansatz poses a constraint on one of the U-duality invariants for the non-BPS solutions with Z \neq 0. We discuss a possible extension of our considerations to the non extremal case.Comment: Some points clarified, a comment on the interpretation of the prepotential W in terms of c-function added, typos corrected. Version to appear on JHE

Alp7/TACC-Alp14/TOG generates long-lived, fast-growing MTs by an unconventional mechanism

Alp14 is a TOG-family microtubule polymerase from S. pombe that tracks plus ends and accelerates their growth. To interrogate its mechanism, we reconstituted dynamically unstable single isoform S. pombe microtubules with full length Alp14/TOG and Alp7, the TACC-family binding partner of Alp14. We find that Alp14 can drive microtubule plus end growth at GTP-tubulin concentrations at least 10-fold below the usual critical concentration, at the expense of increased catastrophe. This reveals Alp14 to be a highly unusual enzyme that biases the equilibrium for the reaction that it catalyses. Alp7/TACC enhances the effectiveness of Alp14, by increasing its occupancy. Consistent with this, we show in live cells that Alp7 deletion produces very similar MT dynamics defects to Alp14 deletion. The ability of Alp7/14 to accelerate and bias GTP-tubulin exchange at microtubule plus ends allows it to generate long-lived, fast-growing microtubules at very low cellular free tubulin concentrations