CO2 reduction with protons and electrons at a boron-based reaction center.

Borohydrides are widely used reducing agents in chemical synthesis and have emerging energy applications as hydrogen storage materials and reagents for the reduction of CO2. Unfortunately, the high energy cost associated with the multistep preparation of borohydrides starting from alkali metals precludes large scale implementation of these latter uses. One potential solution to this issue is the direct synthesis of borohydrides from the protonation of reduced boron compounds. We herein report reactions of the redox series [Au(B2P2)] n (n = +1, 0, -1) (B2P2, 9,10-bis(2-(diisopropylphosphino)phenyl)-9,10-dihydroboranthrene) and their conversion into corresponding mono- and diborohydride complexes. Crucially, the monoborohydride can be accessed via protonation of [Au(B2P2)]-, a masked borane dianion equivalent accessible at relatively mild potentials (-2.05 V vs. Fc/Fc+). This species reduces CO2 to produce the corresponding formate complex. Cleavage of the formate complex can be achieved by reduction (ca. -1.7 V vs. Fc/Fc+) or by the addition of electrophiles including H+. Additionally, direct reaction of [Au(B2P2)]- with CO2 results in reductive disproportion to release CO and generate a carbonate complex. Together, these reactions constitute a synthetic cycle for CO2 reduction at a boron-based reaction center that proceeds through a B-H unit generated via protonation of a reduced borane with weak organic acids

“I don’t want to look sick skinny”: Perceptions of body image and weight loss in Hispanics living with HIV in South Texas

Objective: Obesity is rising in people with HIV (PLWH) and Hispanics. Both HIV and obesity are associated with cardiovascular disease morbidity and mortality. Our goal is to understand perceptions of body image and lifestyle in Hispanics with HIV to adapt interventions appropriately. Methods: We conducted semi-structured interviews with 22 Hispanic PLWH and 6 providers. Purposive sampling selected patient participants across weights and genders. Interviews were coded and analyzed using grounded theory, comparing perspectives between patients with and without obesity, and patients and providers. Results: Participants felt obesity and diabetes were “normal” in the community. Patients exhibited understanding of healthy diet and lifestyle but felt incapable of maintaining either. Traditionally Hispanic foods were blamed for local obesity prevalence. Five patients equated weight with health and weight loss with illness, and four expressed concerns that weight loss could lead to unintentional disclosure of HIV status. Participants with overweight or obesity expressed awareness of their weight and felt shamed by providers. Providers found weight loss interventions to be ineffective. Conclusion: Interventions in this population must address identified barriers: overweight/obesity as a normative value, lack of self-efficacy, cultural beliefs surrounding food, fear of HIV-associated weight loss and stigma, and provider perspectives on intervention futility

Testing the equivalence principle: why and how?

Part of the theoretical motivation for improving the present level of testing of the equivalence principle is reviewed. The general rationale for optimizing the choice of pairs of materials to be tested is presented. One introduces a simplified rationale based on a trichotomy of competing classes of theoretical models.Comment: 11 pages, Latex, uses ioplppt.sty, submitted to Class. Quantum Gra

A new reference genome assembly for the microcrustacean Daphnia pulex

Comparing genomes of closely related genotypes from populations with distinct demographic histories can help reveal the impact of effective population size on genome evolution. For this purpose, we present a high quality genome assembly of Daphnia pulex (PA42), and compare this with the first sequenced genome of this species (TCO), which was derived from an isolate from a population with >90% reduction in nucleotide diversity. PA42 has numerous similarities to TCO at the gene level, with an average amino acid sequence identity of 98.8 and >60% of orthologous proteins identical. Nonetheless, there is a highly elevated number of genes in the TCO genome annotation, with similar to 7000 excess genes appearing to be false positives. This view is supported by the high GC content, lack of introns, and short length of these suspicious gene annotations. Consistent with the view that reduced effective population size can facilitate the accumulation of slightly deleterious genomic features, we observe more proliferation of transposable elements (TEs) and a higher frequency of gained introns in the TCO genome

The Next Generation Virgo Cluster Survey. IX. Estimating the Efficiency of Galaxy Formation on the Lowest-Mass Scales

The Next Generation Virgo Cluster Survey has recently determined the luminosity function of galaxies in the core of the Virgo cluster down to unprecedented magnitude and surface brightness limits. Comparing simulations of cluster formation to the derived central stellar mass function, we attempt to estimate the stellar-to-halo-mass ratio (SHMR) for dwarf galaxies, as it would have been before they fell into the cluster. This approach ignores several details and complications, e.g., the contribution of ongoing star formation to the present-day stellar mass of cluster members, and the effects of adiabatic contraction and/or violent feedback on the subhalo and cluster potentials. The final results are startlingly simple, however; we find that the trends in the SHMR determined previously for bright galaxies appear to extend down in a scale-invariant way to the faintest objects detected in the survey. These results extend measurements of the formation efficiency of field galaxies by two decades in halo mass, or five decades in stellar mass, down to some of the least massive dwarf galaxies known, with stellar masses of $\sim 10^5 M_\odot$.Comment: 18 pages, 12 figures; published in ApJ July 1st 201

Cross modal perception of body size in domestic dogs (Canis familiaris)

While the perception of size-related acoustic variation in animal vocalisations is well documented, little attention has been given to how this information might be integrated with corresponding visual information. Using a cross-modal design, we tested the ability of domestic dogs to match growls resynthesised to be typical of either a large or a small dog to size- matched models. Subjects looked at the size-matched model significantly more often and for a significantly longer duration than at the incorrect model, showing that they have the ability to relate information about body size from the acoustic domain to the appropriate visual category. Our study suggests that the perceptual and cognitive mechanisms at the basis of size assessment in mammals have a multisensory nature, and calls for further investigations of the multimodal processing of size information across animal species

First-principles Calculation of the Formation Energy in MgO-CaO Solid Solutions

The electronic structure and total energy were calculated for ordered and disordered MgO-CaO solid solutions within the multiple scattering theory in real space and the local density approximation. Based on the dependence of the total energy on the unit cell volume the equilibrium lattice parameter and formation energy were determined for different solution compositions. The formation energy of the solid solutions is found to be positive that is in agreement with the experimental phase diagram, which shows a miscibility gap.Comment: 11 pages, 3 figure

Protective effi cacy of prolonged co-trimoxazole prophylaxis in HIV-exposed children up to age 4 years for the prevention of malaria in Uganda: a randomised controlled open-label trial

Background WHO recommends daily co-trimoxazole for children born to HIV-infected mothers from 6 weeks of age until breastfeeding cessation and exclusion of HIV infection. We have previously reported on the eff ectiveness of continuation of co-trimoxazole prophylaxis up to age 2 years in these children. We assessed the protective effi cacy and safety of prolonging co-trimoxazole prophylaxis until age 4 years in HIV-exposed children. Methods We undertook an open-label randomised controlled trial alongside two observational cohorts in eastern Uganda, an area with high HIV prevalence, malaria transmission intensity, and antifolate resistance. We enrolled HIVexposed infants between 6 weeks and 9 months of age and prescribed them daily co-trimoxazole until breastfeeding cessation and HIV-status confi rmation. At the end of breastfeeding, children who remained HIV-uninfected were randomly assigned (1:1) to discontinue co-trimoxazole or to continue taking it up to age 2 years. At age 2 years, children who continued co-trimoxazole prophylaxis were randomly assigned (1:1) to discontinue or continue prophylaxis from age 2 years to age 4 years. The primary outcome was incidence of malaria (defi ned as the number of treatments for new episodes of malaria diagnosed with positive thick smear) at age 4 years. For additional comparisons, we observed 48 HIV-infected children who took continuous co-trimoxazole prophylaxis and 100 HIV-unexposed uninfected children who never received prophylaxis. We measured grade 3 and 4 serious adverse events and hospital admissions. All children were followed up to age 5 years and all analyses were by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00527800. Findings 203 HIV-exposed infants were enrolled between Aug 10, 2007, and March 28, 2008. After breastfeeding ended, 185 children were not infected with HIV and were randomly assigned to stop (n=87) or continue (n=98) co-trimoxazole up to age 2 years. At age 2 years, 91 HIV-exposed children who had remained on co-trimoxazole prophylaxis were randomly assigned to discontinue (n=46) or continue (n=45) co-trimoxazole from age 2 years to age 4 years. We recorded 243 malaria episodes (2·91 per person-years) in the 45 HIV-exposed children assigned to continue cotrimoxazole until age 4 years compared with 503 episodes (5·60 per person-years) in the 46 children assigned to stop co-trimoxazole at age 2 years (incidence rate ratio 0·53, 95% CI 0·39–0·71; p<0·0001). There was no evidence of malaria incidence rebound in the year after discontinuation of co-trimoxazole in the HIV-exposed children who stopped co-trimoxazole at age 2 years, but incidence increased signifi cantly in HIV-exposed children who stopped co-trimoxazole at age 4 years (odds ratio 1·78, 95% CI 1·19–2·66; p=0·005). Incidence of grade 3 or 4 serious adverse events, hospital admissions, or deaths did not signifi cantly diff er between HIV-exposed, HIV-unexposed, and HIV-infected children. Interpretation Continuation of co-trimoxazole prophylaxis up to 4 years of age seems safe and effi cacious to protect HIV-exposed children living in malaria-endemic areas

Helium in superstrong magnetic fields

We investigate the helium atom embedded in a superstrong magnetic field gamma=100-10000 au. All effects due to the finite nuclear mass for vanishing pseudomomentum are taken into account. The influence and the magnitude of the different finite mass effects are analyzed and discussed. Within our full configuration interaction approach calculations are performed for the magnetic quantum numbers M=0,-1,-2,-3, singlet and triplet states, as well as positive and negative z parities. Up to six excited states for each symmetry are studied. With increasing field strength the number of bound states decreases rapidly and we remain with a comparatively small number of bound states for gamma=10^4 au within the symmetries investigated here.Comment: 16 pages, including 14 eps figures, submitted to Phys. Rev.

Parsimonious test of dynamic interaction

In recent years, there have been significant advances in the technology used to collect data on the movement and activity patterns of humans and animals. GPS units, which form the primary source of location data, have become cheaper, more accurate, lighter and less power‐hungry, and their accuracy has been further improved with the addition of inertial measurement units. The consequence is a glut of geospatial time series data, recorded at rates that range from one position fix every several hours (to maximize system lifetime) to ten fixes per second (in high dynamic situations). Since data of this quality and volume have only recently become available, the analytical methods to extract behavioral information from raw position data are at an early stage of development. An instance of this lies in the analysis of animal movement patterns. When investigating solitary animals, the timing and location of instances of avoidance and association are important behavioral markers. In this paper, a novel analytical method to detect avoidance and association between individuals is proposed; unlike existing methods, assumptions about the shape of the territories or the nature of individual movement are not needed. Simulations demonstrate that false positives (type I error) are rare (1%–3%), which means that the test rarely suggests that there is an association if there is none