Phase diagram for non-axisymmetric plasma balls

Plasma balls and rings emerge as fluid holographic duals of black holes and black rings in the hydrodynamic/gravity correspondence for the Scherk-Schwarz AdS system. Recently, plasma balls spinning above a critical rotation were found to be unstable against m-lobed perturbations. In the phase diagram of stationary solutions the threshold of the instability signals a bifurcation to a new phase of non-axisymmetric configurations. We find explicitly this family of solutions and represent them in the phase diagram. We discuss the implications of our results for the gravitational system. Rotating non-axisymmetric black holes necessarily radiate gravitational waves. We thus emphasize that it would be important, albeit possibly out of present reach, to have a better understanding of the hydrodynamic description of gravitational waves and of the gravitational interaction between two bodies. We also argue that it might well be that a non-axisymmetric m-lobed instability is also present in Myers-Perry black holes for rotations below the recently found ultraspinning instability.Comment: 1+22 pages, 3 figures. v2: minor corrections and improvements, matches published versio

Low Friction Flows of Liquids at Nanopatterned Interfaces

With the recent important development of microfluidic systems, miniaturization of flow devices has become a real challenge. Microchannels, however, are characterized by a large surface to volume ratio, so that surface properties strongly affect flow resistance in submicrometric devices. We present here results showing that the concerted effect of wetting . properties and surface roughness may considerably reduce friction of the fluid past the boundaries. The slippage of the fluid at the channel boundaries is shown to be drastically increased by using surfaces that are patterned at the nanometer scale. This effect occurs in the regime where the surface pattern is partially dewetted, in the spirit of the 'superhydrophobic' effects that have been recently discovered at the macroscopic scales. Our results show for the first time that, in contrast to the common belief, surface friction may be reduced by surface roughness. They also open the possibility of a controlled realization of the 'nanobubbles' that have long been suspected to play a role in interfacial slippag

The relation of steady evaporating drops fed by an influx and freely evaporating drops

We discuss a thin film evolution equation for a wetting evaporating liquid on a smooth solid substrate. The model is valid for slowly evaporating small sessile droplets when thermal effects are insignificant, while wettability and capillarity play a major role. The model is first employed to study steady evaporating drops that are fed locally through the substrate. An asymptotic analysis focuses on the precursor film and the transition region towards the bulk drop and a numerical continuation of steady drops determines their fully non-linear profiles. Following this, we study the time evolution of freely evaporating drops without influx for several initial drop shapes. As a result we find that drops initially spread if their initial contact angle is larger than the apparent contact angle of large steady evaporating drops with influx. Otherwise they recede right from the beginning

Some results on blow up for semilinear parabolic problems

The authors describe the asymptotic behavior of blow-up for the semilinear heat equation ut=uxx+f(u) in R×(0,T), with initial data u0(x)>0 in R, where f(u)=up, p>1, or f(u)=eu. A complete description of the types of blow-up patterns and of the corresponding blow-up final-time profiles is given. In the rescaled variables, both are governed by the structure of the Hermite polynomials H2m(y). The H2-behavior is shown to be stable and generic. The existence of H4-behavior is proved. A nontrivial blow-up pattern with a blow-up set of nonzero measure is constructed. Similar results for the absorption equation ut=uxx−up, 0<p<1, are discussed

Sex differences in basal hypothalamic anorectic and orexigenic gene expression and the effect of quantitative and qualitative food restriction

Abstract Background Research into energy balance and growth has infrequently considered genetic sex, yet there is sexual dimorphism for growth across the animal kingdom. We test the hypothesis that in the chicken, there is a sex difference in arcuate nucleus neuropeptide gene expression, since previous research indicates hypothalamic AGRP expression is correlated with growth potential and that males grow faster than females. Because growth has been heavily selected in some chicken lines, food restriction is necessary to improve reproductive performance and welfare, but this increases hunger. Dietary dilution has been proposed to ameliorate this undesirable effect. We aimed to distinguish the effects of gut fullness from nutritional feedback on hypothalamic gene expression and its interaction with sex. Methods Twelve-week-old male and female fast-growing chickens were either released from restriction and fed ad libitum or a restricted diet plus 15% w/w ispaghula husk, a non-nutritive bulking agent, for 2 days. A control group remained on quantitative restriction. Hypothalamic arcuate nucleus neuropeptides were measured using real-time PCR. To confirm observed sex differences, the experiment was repeated using only ad libitum and restricted fed fast-growing chickens and in a genetically distinct breed of ad libitum fed male and female chickens. Linear mixed models (Genstat 18) were used for statistical analysis with transformation where appropriate. Results There were pronounced sex differences: expression of the orexigenic genes AGRP (P < 0.001) and NPY (P < 0.002) was higher in males of the fast-growing strain. In genetically distinct chickens, males had higher AGRP mRNA (P = 0.002) expression than females, suggesting sex difference was not restricted to a fast-growing strain. AGRP (P < 0.001) expression was significantly decreased in ad libitum fed birds but was high and indistinguishable between birds on a quantitative versus qualitative restricted diet. Inversely, gene expression of the anorectic genes POMC and CART was significantly higher in ad libitum fed birds but no consistent sex differences were observed. Conclusion Expression of orexigenic peptides in the avian hypothalamus are significantly different between sexes. This could be useful starting point of investigating further if AGRP is an indicator of growth potential. Results also demonstrate that gut fill alone does not reduce orexigenic gene expression

Young pregnant women's views on the acceptability of screening for chlamydia as part of routine antenatal care

<p>Abstract</p> <p>Background</p> <p>In pregnancy, untreated chlamydia infection has been associated with adverse outcomes for both mother and infant. Like most women, pregnant women infected with chlamydia do not report genital symptoms, and are therefore unlikely to be aware of their infection. The aim of this study was to determine the acceptability of screening pregnant women aged 16-25 years for chlamydia as part of routine antenatal care.</p> <p>Methods</p> <p>As part of a larger prospective, cross-sectional study of pregnant women aged 16-25 years attending antenatal services across Melbourne, Australia, 100 women were invited to participate in a face-to-face, semi structured interview on the acceptability of screening for chlamydia during pregnancy. Women infected with chlamydia were oversampled (n = 31).</p> <p>Results</p> <p>Women had low levels of awareness of chlamydia before the test, retained relatively little knowledge after the test and commonly had misconceptions around chlamydia transmission, testing and sequelae. Women indicated a high level of acceptance and support for chlamydia screening, expressing their willingness to undertake whatever care was necessary to ensure the health of their baby. There was a strong preference for urine testing over other methods of specimen collection. Women questioned why testing was not already conducted alongside other antenatal STI screening tests, particularly in view of the risks chlamydia poses to the baby. Women who tested positive for chlamydia had mixed reactions, however, most felt relief and gratitude at having had chlamydia detected and reported high levels of partner support.</p> <p>Conclusions</p> <p>Chlamydia screening as part of routine antenatal care was considered highly acceptable among young pregnant women who recognized the benefits of screening and strongly supported its implementation as part of routine antenatal care. The acceptability of screening is important to the uptake of chlamydia screening in future antenatal screening strategies.</p

Formation of Sclerotia and Production of Indoloterpenes by Aspergillus niger and Other Species in Section Nigri

Several species in Aspergillus section Nigri have been reported to produce sclerotia on well-known growth media, such as Czapek yeast autolysate (CYA) agar, with sclerotia considered to be an important prerequisite for sexual development. However Aspergillus niger sensu stricto has not been reported to produce sclerotia, and is thought to be a purely asexual organism. Here we report, for the first time, the production of sclerotia by certain strains of Aspergillus niger when grown on CYA agar with raisins, or on other fruits or on rice. Up to 11 apolar indoloterpenes of the aflavinine type were detected by liquid chromatography and diode array and mass spectrometric detection where sclerotia were formed, including 10,23-dihydro-24,25-dehydroaflavinine. Sclerotium induction can thus be a way of inducing the production of new secondary metabolites from previously silent gene clusters. Cultivation of other species of the black aspergilli showed that raisins induced sclerotium formation by A. brasiliensis, A. floridensis A. ibericus, A. luchuensis, A. neoniger, A. trinidadensis and A. saccharolyticus for the first time

Saccadic Eye Movements Minimize the Consequences of Motor Noise

The durations and trajectories of our saccadic eye movements are remarkably stereotyped. We have no voluntary control over these properties but they are determined by the movement amplitude and, to a smaller extent, also by the movement direction and initial eye orientation. Here we show that the stereotyped durations and trajectories are optimal for minimizing the variability in saccade endpoints that is caused by motor noise. The optimal duration can be understood from the nature of the motor noise, which is a combination of signal-dependent noise favoring long durations, and constant noise, which prefers short durations. The different durations of horizontal vs. vertical and of centripetal vs. centrifugal saccades, and the somewhat surprising properties of saccades in oblique directions are also accurately predicted by the principle of minimizing movement variability. The simple and sensible principle of minimizing the consequences of motor noise thus explains the full stereotypy of saccadic eye movements. This suggests that saccades are so stereotyped because that is the best strategy to minimize movement errors for an open-loop motor system

Polymorphisms in the P2X7 receptor gene are associated with low lumbar spine bone mineral density and accelerated bone loss in post-menopausal women

The P2X7 receptor gene (P2RX7) is highly polymorphic with five previously described loss-of-function (LOF) single-nucleotide polymorphisms (SNP; c.151+1G>T, c.946G>A, c.1096C>G, c.1513A>C and c.1729T>A) and one gain-of-function SNP (c.489C>T). The purpose of this study was to determine whether the functional P2RX7 SNPs are associated with lumbar spine (LS) bone mineral density (BMD), a key determinant of vertebral fracture risk, in post-menopausal women. We genotyped 506 post-menopausal women from the Aberdeen Prospective Osteoporosis Screening Study (APOSS) for the above SNPs. Lumbar spine BMD was measured at baseline and at 6–7 year follow-up. P2RX7 genotyping was performed by homogeneous mass extension. We found association of c.946A (p.Arg307Gln) with lower LS-BMD at baseline (P=0.004, β=−0.12) and follow-up (P=0.002, β=−0.13). Further analysis showed that a combined group of subjects who had LOF SNPs (n=48) had nearly ninefold greater annualised percent change in LS-BMD than subjects who were wild type at the six SNP positions (n=84; rate of loss=−0.94%/year and −0.11%/year, respectively, P=0.0005, unpaired t-test). This is the first report that describes association of the c.946A (p.Arg307Gln) LOF SNP with low LS-BMD, and that other LOF SNPs, which result in reduced or no function of the P2X7 receptor, may contribute to accelerated bone loss. Certain polymorphic variants of P2RX7 may identify women at greater risk of developing osteoporosis