14,846 research outputs found
The Effect of Krill Oil Supplementation on Exercise Performance and Markers of Immune Function
Date of Acceptance: 08/09/2015 Acknowledgments We thank the technical support of the Institute of Medical Sciences Musculoskeletal Programme and the Iain Fraser Cytometry Centre.Peer reviewedPublisher PD
Bisectors of the HARPS Cross-Correlation-Function. The dependence on stellar atmospheric parameters
Bisectors of the HARPS cross-correlation function (CCF) can discern between
planetary radial-velocity (RV) signals and spurious RV signals from stellar
magnetic activity variations. However, little is known about the effects of the
stellar atmosphere on CCF bisectors or how these effects vary with spectral
type and luminosity class. Here we investigate the variations in the shapes of
HARPS CCF bisectors across the HR diagram in order to relate these to the basic
stellar parameters, surface gravity and temperature. We use archive spectra of
67 well studied stars observed with HARPS and extract mean CCF bisectors. We
derive previously defined bisector measures (BIS, v_bot, c_b) and we define and
derive a new measure called the CCF Bisector Span (CBS) from the minimum radius
of curvature on direct fits to the CCF bisector. We show that the bisector
measures correlate differently, and non-linearly with log g and T_eff. The
resulting correlations allow for the estimation of log g and T_eff from the
bisector measures. We compare our results with 3D stellar atmosphere models and
show that we can reproduce the shape of the CCF bisector for the Sun.Comment: 13 pages, 20 figures. Accepted by A&
The Effect of Fish Oil, Vitamin D and Protein on URTI Incidence in Young Active People
Novel pharmacological actions of Trequinsin Hydrochloride improve human sperm cell motility and function
Background and purposeAsthenozoospermia is a leading cause of male infertility, but the development of pharmaceuticals to improve sperm motility has been hindered by the lack of effective screening platforms and knowledge of suitable molecular targets. We have demonstrated that a high throughput screening (HTS) strategy in conjunction with established in vitro tests can identify and characterise the action of compounds that improve sperm motility. The study aimed to apply HTS to identify new compounds from a novel small molecule library that increase intracellular calcium, [Ca2+]I, promote human sperm cell motility and systemically determine the mechanism of action. Experimental approach A validated HTS fluorometric [Ca2+]i assay was used to screen an in-house library of compounds. Trequinsin hydrochloride (a phosphodiesterase 3 inhibitor) was selected for detailed molecular (plate reader assays, electrophysiology and cyclic nucleotide measurement) and functional (motility and acrosome reaction) testing in sperm from healthy volunteer donors and, where possible, patients. Key resultsThe fluorometric analysis identified Trequinsin as an efficacious agonist of [Ca2+]i, although less potent than progesterone (P4). Functionally, Trequinsin significantly increased cell hyperactivation and penetration into viscous medium in all donor sperm samples and cell hyperactivation in 22/25 (88%) patient sperm samples. The Trequinsin-induced [Ca2+]i response was cross-desensitised consistently by prostaglandin E1 but not with P4. Whole-cell patch clamp electrophysiology confirmed that Trequinsin activates CatSper and partially inhibits potassium channel activity. Trequinsin also increases intracellular cGMP. Conclusion and Implications Trequinsin exhibits a novel pharmacological profile in human sperm and may be a suitable lead compound for the development of new pharmaceuticals to improve patient sperm function and fertilisation potential
Numerical Algebraic Geometry: A New Perspective on String and Gauge Theories
The interplay rich between algebraic geometry and string and gauge theories
has recently been immensely aided by advances in computational algebra.
However, these symbolic (Gr\"{o}bner) methods are severely limited by
algorithmic issues such as exponential space complexity and being highly
sequential. In this paper, we introduce a novel paradigm of numerical algebraic
geometry which in a plethora of situations overcomes these short-comings. Its
so-called 'embarrassing parallelizability' allows us to solve many problems and
extract physical information which elude the symbolic methods. We describe the
method and then use it to solve various problems arising from physics which
could not be otherwise solved.Comment: 36 page
Programas internacionais de capacitação em pesquisa para enfermeiros no estudo do fenómeno das drogas na América Latina: desafios e perspectivas
The First International Research Capacity-Building Program for Nurses to Study the Drug Phenomenon in the Americas is a result of a partnership between the Inter-American Drug Abuse Control Commission (CICAD) of the Organization of American States (OAS) and the Faculty of Nursing in the University of Alberta, with financial support from the Government of Canada. The program was divided into two parts. The first part of the program was held at the University of Alberta in Edmonton, Alberta, Canada. It involved capacity-building in research methodologies at the Faculty of Nursing, which lead to the preparation of four multi-centric research proposals for drug demand reduction in the home countries of the eleven participants in the program. The second part of the program was related to the implementation of multi-centric research proposals in seven countries in Latin America and in Canada. This program presented expertise in research methodology to members of Latin American Schools of Nursing and introduced Latin American expertise to members of a Canadian Faculty of Nursing. The International Research Capacity-Building Program for Nurses to Study the Drug Phenomenon in the Americas has fostered the kind of inter-cultural respect and mutual appreciation necessary to confront the global health problem of the abuse of both licit and illicit drugs.El Primer Programa Internacional de Capacitación en Investigación para Enfermeros en el Estudio del Fenómeno de las Drogas en las Américas resultó de una colaboración entre la Comisión Interamericana para el Control del Abuso de Drogas (CICAD) de la Organización de los Estados Americanos (OEA) y la Facultad de Enfermería en la Universidad de Alberta, con apoyo financiero del Gobierno de Canadá. El programa fue dividido en dos partes. La primera parte del programa se organizó en la Universidad de Alberta en Edmonton, Alberta, Canadá. Abarcó la capacitación en metodologías de investigación en la Facultad de Enfermería, que llevó a la preparación de cuatro propuestas de investigación multicéntrica con vistas a la reducción de la demanda de drogas en los países de origen de los once participantes en el programa. La segunda parte del programa estaba relacionada a la implementación de propuestas de investigación multicéntrica en siete países de América Latina y en Canadá. Este programa presentó conocimientos especializados en metodologías de investigación a miembros de Escuelas de Enfermería latinoamericanas e introdujo los conocimientos especializados latinoamericanos a miembros de una Facultad de Enfermería canadiense. El Programa Internacional de Capacitación en Investigación para Enfermeros en el Estudio del Fenómeno de las Drogas en las Américas estimuló el tipo de respecto intercultural y apreciación mutua necesario para confrontar el problema de salud global del abuso de drogas lícitas e ilícitas.O Primeiro Programa Internacional de Capacitação para Enfermeiros no Estudo do Fenômeno das Drogas nas Américas é resultado de uma parceria entre a Comissão Interamericana para o Controle do Abuso das Drogas (CICAD) da Organização dos Estados Americanos (OEA) e a Faculdade de Enfermagem da Universidade de Alberta, com apoio financeiro do Governo do Canadá. O programa foi dividido em duas partes. A primeira parte do programa foi realizada na Universidade de Alberta em Edmonton, Alberta, Canadá. Compreendeu a capacitação em metodologias de pesquisa na Faculdade de Enfermagem, que levou à preparação de quatro propostas de pesquisas multicêntricas para a redução da demanda de drogas nos países de origem dos onze participantes no programa. A segunda parte do programa estava relacionada à implementação de propostas de pesquisa multicêntricas em sete países da América Latina e no Canadá. Este programa apresentou expertise em metodologias de pesquisa a membros de Escolas de Enfermagem latino-americanas e introduziu expertise latino-americana a membros de uma Faculdade de Enfermagem canadense. O Primeiro Programa Internacional de Capacitação para Enfermeiros no Estudo do Fenômeno das Drogas nas Américas estimulou o tipo de respeito intercultural e apreço mútuo necessário para confrontar o problema de saúde global do abuso das drogas lícitas e ilícitas
Thermal Cycling Stability of Silica Membranes for Gas Separation
Hydrogen is being seen as an alternative energy carrier to conventional hydrocarbons to reduce greenhouse gas emissions. High efficiency separation technologies to remove hydrogen from the greenhouse gas, carbon dioxide, are therefore in growing demand. Traditional thermodynamic separation systems utilise distillation, absorption and adsorption, but are limited in efficiency at compact scales. Molecular sieve silica (MSS) membranes can perform this separation as they have high permselectivity of hydrogen to carbon dioxide, but their stability under thermal cycling is not well reported. In this work we exposed a standard MSS membrane and a carbonised template MSS (CTMSS) membrane to thermal cycling from 100 to 450°C. The standard MSS and carbonised template CTMSS membranes both showed permselectivity of helium to nitrogen dropping from around 10 to 6 in the first set of cycles, remaining stable until the last test. The permselectivity drop was due to small micropore collapse, which occurred via structure movement during cycling. Simulating single stage membrane separation with a 50:50 molar feed of H2:CO2, H2 exiting the permeate stream would start at 79% and stabilise at 67%. Higher selectivity membranes showed less of a purity drop, indicating the margin at which to design a stable membrane separation unit for CO2 capture
Study of the impact of the post-MS evolution of the host star on the orbits of close-in planets. I. Sample definition and physical properties
Context: To date, more than 30 planets have been discovered around giant
stars, but only one of them has been found to be orbiting within 0.6 AU from
the host star, in direct contrast to what is observed for FGK dwarfs. This
result suggests that evolved stars destroy/engulf close-in planets during the
red giant phase.
Aims: We are conducting a radial velocity survey of 164 bright G and K giant
stars in the southern hemisphere with the aim of studying the effect of the
host star evolution on the inner structure of planetary systems. In this paper
we present the spectroscopic atmospheric parameters (\Teff, \logg, ,
[Fe/H]) and the physical properties (mass, radius, evolutionary status) of the
program stars. In addition, rotational velocities for all of our targets were
derived.
Methods: We used high resolution and high S/N spectra to measure the
equivalent widths of many Fe{\sc\,i} and Fe{\sc\,ii} lines, which were used to
derive the atmospheric parameters by imposing local thermodynamic and
ionization equilibrium. The effective temperatures and metallicities were used,
along with stellar evolutionary tracks to determine the physical properties and
evolutionary status of each star.
Results: We found that our targets are on average metal rich and they have
masses between \,1.0\,M and 3.5\,M. In addition, we found
that 122 of our targets are ascending the RGB, while 42 of them are on the HB
phase.Comment: Accepted for publication in A&
Do Staphylococcus epidermidis genetic clusters predict isolation sources?
Staphylococcus epidermidis is a ubiquitous colonizer of human skin and a common cause of medical device-associated infections. The extent to which the population genetic structure of S. epidermidis distinguishes commensal from pathogenic isolates is unclear. Previously, Bayesian clustering of 437 multilocus sequence types (STs) in the international database revealed a population structure of six genetic clusters (GCs) that may reflect the species' ecology. Here, we first verified the presence of six GCs, including two (GC3 and GC5) with significant admixture, in an updated database of 578 STs. Next, a single nucleotide polymorphism (SNP) assay was developed that accurately assigned 545 (94%) of 578 STs to GCs. Finally, the hypothesis that GCs could distinguish isolation sources was tested by SNP typing and GC assignment of 154 isolates from hospital patients with bacteremia and those with blood culture contaminants and from nonhospital carriage. GC5 was isolated almost exclusively from hospital sources. GC1 and GC6 were isolated from all sources but were overrepresented in isolates from nonhospital and infection sources, respectively. GC2, GC3, and GC4 were relatively rare in this collection. No association was detected between fdh-positive isolates (GC2 and GC4) and nonhospital sources. Using a machine learning algorithm, GCs predicted hospital and nonhospital sources with 80% accuracy and predicted infection and contaminant sources with 45% accuracy, which was comparable to the results seen with a combination of five genetic markers (icaA, IS256, sesD [bhp], mecA, and arginine catabolic mobile element [ACME]). Thus, analysis of population structure with subgenomic data shows the distinction of hospital and nonhospital sources and the near-inseparability of sources within a hospital
Path integral Monte Carlo simulations for rigid rotors and their application to water
In this work the path integral formulation for rigid rotors, proposed by
M\"user and Berne [Phys. Rev. Lett. {\bf 77}, 2638 (1996)], is described in
detail. It is shown how this formulation can be used to perform Monte Carlo
simulations of water. Our numerical results show that whereas some properties
of water can be accurately reproduced using classical simulations with an
empirical potential which, implicitly, includes quantum effects, other
properties can only be described quantitatively when quantum effects are
explicitly incorporated. In particular, quantum effects are extremely relevant
when it comes to describing the equation of state of the ice phases at low
temperatures, the structure of the ices at low temperatures, and the heat
capacity of both liquid water and the ice phases. They also play a minor role
in the relative stability of the ice phases.Comment: to appear in Molecular Physics (2011
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