Coherent spinor dynamics in a spin-1 Bose condensate

Collisions in a thermal gas are perceived as random or incoherent as a consequence of the large numbers of initial and final quantum states accessible to the system. In a quantum gas, e.g. a Bose-Einstein condensate or a degenerate Fermi gas, the phase space accessible to low energy collisions is so restricted that collisions be-come coherent and reversible. Here, we report the observation of coherent spin-changing collisions in a gas of spin-1 bosons. Starting with condensates occupying two spin states, a condensate in the third spin state is coherently and reversibly created by atomic collisions. The observed dynamics are analogous to Josephson oscillations in weakly connected superconductors and represent a type of matter-wave four-wave mixing. The spin-dependent scattering length is determined from these oscillations to be -1.45(18) Bohr. Finally, we demonstrate coherent control of the evolution of the system by applying differential phase shifts to the spin states using magnetic fields.Comment: 19 pages, 3 figure

Molecular evolution: sex accelerates adaptation

An analysis confirms the long-standing theory that sex increases the rate of adaptive evolution by accelerating the speed at which beneficial mutations sweep through sexual, as opposed to asexual, populations

An international comparative study of blood pressure in populations of European vs. African descent

Background: The consistent finding of higher prevalence of hypertension in US blacks compared to whites has led to speculation that African-origin populations are particularly susceptible to this condition. Large surveys now provide new information on this issue. Methods: Using a standardized analysis strategy we examined prevalence estimates for 8 white and 3 black populations (N = 85,000 participants). Results: The range in hypertension prevalence was from 27 to 55% for whites and 14 to 44% for blacks. Conclusions: These data demonstrate that not only is there a wide variation in hypertension prevalence among both racial groups, the rates among blacks are not unusually high when viewed internationally. These data suggest that the impact of environmental factors among both populations may have been under-appreciated

Yukawa Textures From Heterotic Stability Walls

A holomorphic vector bundle on a Calabi-Yau threefold, X, with h^{1,1}(X)>1 can have regions of its Kahler cone where it is slope-stable, that is, where the four-dimensional theory is N=1 supersymmetric, bounded by "walls of stability". On these walls the bundle becomes poly-stable, decomposing into a direct sum, and the low energy gauge group is enhanced by at least one anomalous U(1) gauge factor. In this paper, we show that these additional symmetries can strongly constrain the superpotential in the stable region, leading to non-trivial textures of Yukawa interactions and restrictions on allowed masses for vector-like pairs of matter multiplets. The Yukawa textures exhibit a hierarchy; large couplings arise on the stability wall and some suppressed interactions "grow back" off the wall, where the extended U(1) symmetries are spontaneously broken. A number of explicit examples are presented involving both one and two stability walls, with different decompositions of the bundle structure group. A three family standard-like model with no vector-like pairs is given as an example of a class of SU(4) bundles that has a naturally heavy third quark/lepton family. Finally, we present the complete set of Yukawa textures that can arise for any holomorphic bundle with one stability wall where the structure group breaks into two factors.Comment: 53 pages, 4 figures and 13 table

Numerical Hermitian Yang-Mills Connections and Vector Bundle Stability in Heterotic Theories

A numerical algorithm is presented for explicitly computing the gauge connection on slope-stable holomorphic vector bundles on Calabi-Yau manifolds. To illustrate this algorithm, we calculate the connections on stable monad bundles defined on the K3 twofold and Quintic threefold. An error measure is introduced to determine how closely our algorithmic connection approximates a solution to the Hermitian Yang-Mills equations. We then extend our results by investigating the behavior of non slope-stable bundles. In a variety of examples, it is shown that the failure of these bundles to satisfy the Hermitian Yang-Mills equations, including field-strength singularities, can be accurately reproduced numerically. These results make it possible to numerically determine whether or not a vector bundle is slope-stable, thus providing an important new tool in the exploration of heterotic vacua.Comment: 52 pages, 15 figures. LaTex formatting of figures corrected in version 2

Numerical Hermitian Yang-Mills Connections and Kahler Cone Substructure

We further develop the numerical algorithm for computing the gauge connection of slope-stable holomorphic vector bundles on Calabi-Yau manifolds. In particular, recent work on the generalized Donaldson algorithm is extended to bundles with Kahler cone substructure on manifolds with h^{1,1}>1. Since the computation depends only on a one-dimensional ray in the Kahler moduli space, it can probe slope-stability regardless of the size of h^{1,1}. Suitably normalized error measures are introduced to quantitatively compare results for different directions in Kahler moduli space. A significantly improved numerical integration procedure based on adaptive refinements is described and implemented. Finally, an efficient numerical check is proposed for determining whether or not a vector bundle is slope-stable without computing its full connection.Comment: 38 pages, 10 figure

Attribution of responsibility for sexual crimes beyond individual actors – construction of responsibility of offenders, victims and society in laypersons’ explanations

This study analyses laypersons’ explanations for sexual violence. It focusses on how the responsibility for sexual crimes is constructed and attributed, and moreover, what kind of effect this has on the attribution of blame. The research data consist of 105 opinion pieces published in the leading Finnish newspaper since the beginning of the 21st century. The theory-driven qualitative analysis utilises attribution theory and focusses on laypersons’ interpretations and explanations for unusual acts and events deviating from social norms. Attribution theory is commonly utilised in relation to micro-level actors, the offender and the victim, whereas in this article, it is broadened to include also society as a macro-level actor. The analysis reveals that the construction of responsibility derives from (I) the chronological presentation and explanation of sexual crimes; especially (II) the causality attached to chronological phases, which emphasises the victim’s actions prior to the crime; and (III) the construction of active female agency against male passivity or absence of the perpetrator. Moreover, blame is based on a combination of active agency, produced in the analysed explanations, and stereotypical features connected to female gender (e.g. rape myths)

Characteristics of Mothers Caring for Children During Episodes of Homelessness

This study provides a description of the physical, psychological, and substance use problems of adult homeless women who are and are not caring for children. We also examined differences in the characteristics of these two groups of women. Interviews were conducted with 148 homeless women from three mid-sized U.S. cities, 24.3% of whom were caring for at least one child. Our results showed that women caring for children were more likely to be sheltered and have health insurance. Homeless women caring for children and solitary homeless women were generally similar in terms of substance abuse problems. However, rates of Borderline Personality Disorder were higher among women caring for children than among solitary homeless women. Our results are somewhat consistent with previous research, with the exception of substance abuse problems and mental health problems, which were shown to be equally problematic for all women, regardless of current caregiving status

People of the British Isles: preliminary analysis of genotypes and surnames in a UK control population

There is a great deal of interest in fine scale population structure in the UK, both as a signature of historical immigration events and because of the effect population structure may have on disease association studies. Although population structure appears to have a minor impact on the current generation of genome-wide association studies, it is likely to play a significant part in the next generation of studies designed to search for rare variants. A powerful way of detecting such structure is to control and document carefully the provenance of the samples involved. Here we describe the collection of a cohort of rural UK samples (The People of the British Isles), aimed at providing a well-characterised UK control population that can be used as a resource by the research community as well as providing fine scale genetic information on the British population. So far, some 4,000 samples have been collected, the majority of which fit the criteria of coming from a rural area and having all four grandparents from approximately the same area. Analysis of the first 3,865 samples that have been geocoded indicates that 75% have a mean distance between grandparental places of birth of 37.3km, and that about 70% of grandparental places of birth can be classed as rural. Preliminary genotyping of 1,057 samples demonstrates the value of these samples for investigating fine scale population structure within the UK, and shows how this can be enhanced by the use of surnames

Effects of dietary plant-derived phytonutrients on the genome-wide profiles and coccidiosis resistance in the broiler chickens

<p>Abstract</p> <p>Background</p> <p>The present study was conducted to investigate the effects of dietary plant-derived phytonutrients, carvacrol, cinnamaldehyde and Capsicum oleoresin, on the translational regulation of genes associated with immunology, physiology and metabolism using high-throughput microarray analysis and <it>in vivo</it> disease challenge model of avian coccidiosis.</p> <p>Methods</p> <p>In this study, we used nutrigenomics technology to investigate the molecular and genetic mechanisms of dietary modulation of host innate immunity and metabolism by three phytonutrients. To validate their immunomodulatory effects in a disease model, young broiler chickens fed a standard diet supplemented with three phytochemicals (carvacrol, cinnamaldehyde, and Capsicum oleoresin) from one day post-hatch were orally challenged with <it>E. acervulina</it>. The body weight gain and fecal oocyst production were used to evaluate coccidiosis disease parameters.</p> <p>Results</p> <p>Analysis of global gene expression profiles of intestinal tissues from phytonutrient-fed birds indicated that Capsicum oleoresin induced the most gene changes compared to the control group where many of these genes were associated with those of metabolism and immunity. The most reliable network induced by dietary cinnamaldehyde treatment was related with the functions of antigen presentation, humoral immune response, and inflammatory disease. Furthermore, dietary supplementation with these phytonutrients significantly protected broiler chickens against live coccidiosis challenge infection based on body weight and parasite fecundity.</p> <p>Conclusions</p> <p>The results of this study provide clear evidence to support the idea that plant-derived phytochemicals possess immune-enhancing properties in chickens and these new findings create a new possibility to develop effective drug-free alternative strategies for disease control for poultry infectious diseases.</p