A Molecular Platinum Cluster Junction: A Single-Molecule Switch

We present a theoretical study of the electronic transport through single-molecule junctions incorporating a Pt6 metal cluster bound within an organic framework. We show that the insertion of this molecule between a pair of electrodes leads to a fully atomically engineered nano-metallic device with high conductance at the Fermi level and two sequential high on/off switching states. The origin of this property can be traced back to the existence of a HOMO which consists of two degenerate and asymmetric orbitals, lying close in energy to the Fermi level of the metallic leads. Their degeneracy is broken when the molecule is contacted to the leads, giving rise to two resonances which become pinned close to the Fermi level and display destructive interference.Comment: 4 pages, 4 figures. Reprinted (adapted) with permission from J. Am. Chem. Soc., 2013, 135 (6), 2052. Copyright 2013 American Chemical Societ

The acyclic group dichotomy

Two extremal classes of acyclic groups are discussed. For an arbitrary group G, there is always a homomorphism from an acyclic group of cohomological dimension 2 onto the maximum perfect subgroup of G, and there is always an embedding of G in a binate (hence acyclic) group. In the other direction, there are no nontrivial homomorphisms from binate groups to groups of finite cohomological dimension. Binate groups are shown to be of significance in relation to a number of important K-theoretic isomorphism conjectures.Comment: To appea

Entropic effects on the structure of Lennard-Jones clusters

We examine in detail the causes of the structural transitions that occur for those small Lennard-Jones clusters that have a non-icosahedral global minima. Based on the principles learned from these examples we develop a method to construct structural phase diagrams that show in a coarse-grained manner how the equilibrium structure of large clusters depends on both size and temperature. The method can be augmented to account for anharmonicity and quantum effects. Our results illustrate that the vibrational entropy can play a crucial role in determining the equilibrium structure of a cluster.Comment: 13 pages, 9 figure

Effect of exogenous emulsifier and different fat sources on the performance, carcass characteristics, nutrient digestibility, and serum lipid profile of broiler chickens

A study was conducted to evaluate the effect of an emulsifier on reduced-energy diets using two fat sources for broilers. The study was designed as a 2 x 3 factorial arrangement of treatments. The first factor was 2 fat sources (poultry fat or beef tallow). The second factor was a basal diet with the recommended energy levels, a diet with a 0.83 MJ/kg of energy reduction, and a diet with an energy reduction and inclusion of 1 g emulsifier/kg of diet. The emulsifier used in this study was composed of soy lecithin and polyethylene glycol ricinoleate. The emulsifier increased apparent metabolizable energy (AME) and apparent metabolizable energy corrected for nitrogen balance (AMEn) in beef tallow diets compared to energy-reduced diets (P<0.001). Broilers fed poultry fat had higher weights and weight gains at 35 and 42 d of age (p=0.001), and they had higher daily deposition of fat in the carcass (P = 0.025) when compared to diets with beef tallow. The inclusion of emulsifiers in broiler diets improves AME and AMEn but did not affect the energy reduction diets, whichresulted in reduced performance, decreasing daily fat deposition, but without effects on serum lipid profile in broilers.Um estudo foi conduzido para avaliar o efeito de um emulsificante em dietas com baixo teor de energia usando duas fontes de gordura para frangos de corte. O estudo foi delineado em arranjo fatorial 2 x 3 de tratamentos, o primeiro fator foi 2 fontes de gordura (gordura de frango ou sebo bovino) e o segundo fator uma dieta basal com os níveis de energia recomendados, uma dieta com 0,83 MJ / kg de redução de energia e uma dieta com redução de energia e inclusão de 1 g de emulsionante / kg de dieta (composto de lecitina de soja e ricinoleato de polietilenoglicol). O emulsificante aumentou a energia metabolizável aparente (EMA) e a energia metabolizável aparente corrigida para o balanço de nitrogênio (EMAn) em dietas com sebo bovino em comparação com dietas com redução de energia (P <0,001). Frangos de corte alimentados com gordura de frango apresentam maiores pesos e ganhos de peso aos 35 e 42 dias de idade (p=0,001), e maior deposição diária de gordura na carcaça (P=0,025) quando comparados às dietas com sebo bovino. O emulsificante incluído nas dietas de frangos de corte melhora a EMA e EMAn, mas não supre a redução energética, causando efeitos negativos no desempenho, diminuindo a deposição diária de gordura, mas sem efeitos no perfil lipídico sérico em frangos de corte

Blind source separation aided characterization of the γ′ strengthening phase in an advanced nickel-based superalloy by spectroscopic 4D electron microscopy

The γ’ strengthening phase in an advanced nickel-based superalloy, ATI 718Plus, was characterized using a blind source separation applied to a four dimensional X-ray microanalysis dataset obtained by scanning transmission electron microscopy. Selected patterns in the X-ray spectra identified by independent component analysis were found to be spatially and chemically representative of the matrix (γ) and precipitate phases (γ’) present in the superalloy, enabling their size, shape and distribution to be determined. The three dimensional chemical reconstruction of the microstructure may provide insight into the role of the various alloying elements in the evolution of the microstructure at the nano-scale.The research leading to these results has received funding from the European Union Seventh Framework Programme under Grant Agreement 312483 - ESTEEM2 (Integrated Infrastructure Initiative-I3), as well as from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC grant agreement 291522 - 3DIMAGE. D.R. acknowledges support from the Royal Society’s Newton International Fellowship scheme. RKL acknowledges a Junior Research Fellowship at Clare College. RK acknowledges financial support from Rolls-Royce, EPSRC and the BMWi under EP/H022309/1, EP/H500375/1 and grant number 20T0813. F.d.l.P. and C.D. acknowledge 26 funding from the ERC under grant no. 259619 PHOTO EM. Special thanks to Giorgio Divitini and Lech Staniewicz for preparation of the FIB needle specimen and to Stephen A Croxall for SEM/FIB imaging.This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.actamat.2016.01.04

Specific staining of human chromosomes in Chinese hamster x man hybrid cell lines demonstrates interphase chromosome territories

In spite of Carl Rabl's (1885) and Theodor Boveri's (1909) early hypothesis that chromosomes occupy discrete territories or domains within the interphase nucleus, evidence in favor pf this hypothesis has been limited and indirect so far in higher plants and animals. The alternative possibility that the chromatin fiber of single chromosomes might be extended throughout the major part of even the whole interphase nucleus has been considered for many years. In the latter case, chromosomes would only exist as discrete chromatin bodies during mitosis but not during interphase. Both possibilities are compatible with Boveri's well established paradigm of chromosome individuality. Here we show that an active human X chromosome contained as the only human chromosome in a Chinese hamster x man hybrid cell line can be visualized both in metaphse plates and in interphase nuclei after in situ hybridization with either 3H- or biotin-labeled human genomic DNA. We demonstrate that this chromosome is organized as a distinct chromatin body throughout interphase. In addition, evidence for the territorial organization of human chromosomes is also presented for another hybrid cell line containing several autosomes and the human X chromosome. These findings are discussed in the context of our present knowledge of the organization and topography of interphase chromosomes. General applications of a strategy aimed at specific staining of individual chromosomes in experimental and clinical cytogenetics are briefly considered

Why are convertible bond announcements associated with increasingly negative issuer stock returns? An arbitrage-based explanation

While convertible offerings announced between 1984 and 1999 induce average abnormal stock returns of −1.69%, convertible announcement effects over the period 2000–2008 are more than twice as negative (−4.59%). We hypothesize that this evolution is attributable to a shift in the convertible bond investor base from long-only investors towards convertible arbitrage funds. These funds buy convertibles and short the underlying stocks, causing downward price pressure. Consistent with this hypothesis, we find that the differences in announcement returns between the Traditional Investor period (1984–1999) and the Arbitrage period (2000–September 2008) disappear when controlling for arbitrage-induced short selling associated with a range of hedging strategies. Post-issuance stock returns are also in line with the arbitrage explanation. Average announcement effects of convertibles issued during the Global Financial Crisis are even more negative (−9.12%), due to a combination of short-selling price pressure and issuer, issue, and macroeconomic characteristics associated with these offerings

Objectively measured physical activity and fat mass in a large cohort of children

Background Previous studies have been unable to characterise the association between physical activity and obesity, possibly because most relied on inaccurate measures of physical activity and obesity. Methods and Findings We carried out a cross sectional analysis on 5,500 12-year-old children enrolled in the Avon Longitudinal Study of Parents and Children. Total physical activity and minutes of moderate and vigorous physical activity (MVPA) were measured using the Actigraph accelerometer. Fat mass and obesity (defined as the top decile of fat mass) were measured using the Lunar Prodigy dual x-ray emission absorptiometry scanner. We found strong negative associations between MVPA and fat mass that were unaltered after adjustment for total physical activity. We found a strong negative dose-response association between MVPA and obesity. The odds ratio for obesity in adjusted models between top and the bottom quintiles of minutes of MVPA was 0.03 (95% confidence interval [CI] 0.01-0.13, p-value for trend < 0.0001) in boys and 0.36 (95% CI 0.17-0.74, p-value for trend = 0.006) in girls. Conclusions We demonstrated a strong graded inverse association between physical activity and obesity that was stronger in boys. Our data suggest that higher intensity physical activity may be more important than total activity

What are we measuring? Convergence of leadership with interpersonal and non-interpersonal personality.

Since leadership styles have been most commonly defined in terms of interpersonal influence, one would assume that they have their main projections on the interpersonal circumplex. In this study, the relations between leadership styles from the Multifactor Leadership Questionnaire and Leader Behaviour Description Questionnaire and both interpersonal and HEXACO personality scales are investigated. As expected, charismatic leadership and leader's consideration have strong projections on the interpersonal circumplex, with main projections on the warm-agreeable octant. Transactional leadership, passive leadership, and task-oriented leadership have considerably weaker or no projections on the circumplex. Leader's consideration is most strongly related to interpersonal personality while both transactional and passive leadership are most strongly related to non-interpersonal personality. It is concluded that especially charismatic leadership and leader's consideration are captured almost fully by the HEXACO personality inventory. Copyright © 2008 SAGE Publications