Search results for " effect"
showing 10 items of 7524 documents
Mössbauer Emission Spectroscopy of Mixed-Valency after Nuclear Decay in Iron Complexes
1991
The population of anomalous spin states and aliovalent charge states of iron induced by the 57 Co(EC)57 Fe nuclear decay in polycristalline transition metal compounds was studied by means of Coincidence Mossbauer Emission Spectroscopy (CMES), that is Time-Differential Mossbauer Emission Spectroscopy (TDMES) as well as γ/Xray-Coincidence Mossbauer Emission Spectroscopy (γ/X-CMES). By use of time-integral Mossbauer emission spectroscopy (TIMES) we have observed anomalous high spin (S = 2) states of 57 Fe(II) in the system [57Co/Co(phen)3(ClO 4)2 with increasing intensities on lowering the temperature. With TDMES we followed quantitatively the high spin-low spin relaxation kinetics in this com…
Theoretical study of Fe doping and oxidation–reduction influence on the photorefractive effect in BaTiO_3
1993
We numerically solve charge-transport and Poisson equations for photorefractive BaTiO3 single crystals with a band model, using four impurity levels, Fe2+–Fe3+, Fe3+–Fe4+, VO••–VO•, and VO•-VOx. Densities and photoinduced spatial distributions of each population are computed as a function of annealing O partial pressure. Space-charge field and beam-coupling gain are also computed as a function of annealing O partial pressure, temperature, Fe concentration, grating wave vector, and light intensity. We discuss the intervening mechanism of impurity centers and the correlations between experimental conditions of crystal growth, oxidation–reduction treatments, and measurement parameters.
Two‐Dimensional Electron Gas Effects on the Photoluminescence from a Nonintentionally Doped AlGaN/GaN Heterojunction
2002
Photoluminescence measurements on an AlGaN/GaN single heterojunction (SH), where piezoelectric and spontaneous polarization effects confine a two-dimensional electron gas (2DEG), are presented. Well-defined emissions between the bulk excitonic transitions and their LO-phonon replica are attributed to spatially indirect excitons located close to the interface. The strong interfacial electric field separates photogenerated holes and electrons, weakening their Coulomb interaction and causing a blueshift with increasing excitation intensity due to carrier population effects. In addition, direct experimental proof is obtained by applying an electric field normal to the interface. An energy shift…
150 years of rowing faster: what are the sources of more and more speed?
2015
Rowing has a 150 yr+ competitive history. Examining results from historic races like Oxford-Cambridge (established 1829) and the world championships (established 1893) reveals a linear increase in boat speed by 2-3% per decade. Boat velocity increases if propulsive power is increased and/or power losses are reduced. Over time, the propulsive power capacity of elite rowers has increased. Part of this increase is a result of recruiting athletes from a population that has become taller (1-3 cm per decade) and heavier. Modern world class rowers are typically 190-200 cm tall and weigh 90-100 kg. However, physical capacity does not scale directly with body dimensions but conforms instead to biolo…
Fitness differences and persistent founder effects determine the clonal composition during population build-up in Daphnia
2014
During the initial stages of population build-up in new habitats, the time at which immigrants arrive may infl uence their contribution to the population and thus determine population genetic structure. While the numerical advantage associated with founder eff ects may promote dominance of the off spring of early colonizers, fi tness diff erences associated with ecological diff erences among genotypes may potentially overwhelm these founder eff ects. We conducted an outdoor mesocosm experiment to test whether the sequence of arrival determines the relative contribution of genetic lineages (clones) to populations of the water fl ea Daphnia . A set of D. galeata clones was inoculated pairwise…
Life in varying environments: experimental evidence for delayed effects of juvenile environment on adult life history
2011
Summary 1. The effects of environment experienced during early development on phenotype as an adult has started to gain vast amounts of interest in various taxa. Some evidence on long-term effects of juvenile environment is available, but replicated experimental studies in wild animals are still lacking. 2. Here we report the first replicated experiment in wild mammals which examines the long-term effects of juvenile and adult environments on individual fitness (reproduction, survival and health). The early development of bank vole (Myodes glareolus) individuals took place in either foodsupplemented or un-supplemented outdoor enclosures. After the summer, adult individuals were reciprocally…
Cannabis-associated symptom profiles in patients with first episode psychosis and population controls
2019
AbstractObjectiveThe evidence is mixed on whether cannabis use is associated with a particular symptomatology in first episode psychosis (FEP) patients.The authors set out to investigate a) patterns of association between cannabis use and transdiagnostic symptom dimensions; b) whether the extent of use of cannabis contributes to the variation in clinical and subclinical symptom profiles.MethodThe authors analysed data from 901 patients and 1235 controls recruited across six countries, as part of the European Network of National Schizophrenia Networks Studying Gene-Environment Interactions (EU-GEI) study. Item response modelling was used to estimate two bifactor models, which included genera…
Bayesian reanalysis of a quantitative trait locus accounting for multiple environments by scaling in broilers1
2006
A Bayesian method was developed to handle QTL analyses of multiple experimental data of outbred populations with heterogeneity of variance between sexes for all random effects. The method employed a scaled reduced animal model with random polygenic and QTL allelic effects. A parsimonious model specification was applied by choosing assumptions regarding the covariance structure to limit the number of parameters to estimate. Markov chain Monte Carlo algorithms were applied to obtain marginal posterior densities. Simulation demonstrated that joint analysis of multiple environments is more powerful than separate single trait analyses of each environment. Measurements on broiler BW obtained from…
Context of validation of non-formal and informal learning in Spain: a comprehensive view
2019
The system of validation and accreditation of professional qualifications in Spain is offered as a certification opportunity, especially for vulnerable groups. The procedure is presented as an evaluative proposal that allows some inequalities associated with training and employment to be addressed. In this article we analyse whether this system really fosters social cohesion, considering the political situation that frames the procedure and the educational approach underlying it. The research methodology combines the documentary analysis and interviews with the application of the Delphi method. The most relevant results show that the socio-political context is favourable to competences accr…
A novel rationale for targeting FXI: Insights from the hemostatic miRNA targetome for emerging anticoagulant strategies
2018
Abstract The treatment and prevention of thrombosis is currently under a period of rapid change with the replacement of traditional anticoagulant vitamin K antagonists, which impair the biosynthesis of a wide range of blood coagulation factors, with direct oral anticoagulants (DOACs), which specifically target factors FXa or FIIa. Nevertheless therapeutic targeting of blood coagulation is an inherently difficult task as it interferes with the delicate balance of pro- and anticoagulant activities. Although anticoagulants are employed in millions of thrombophilic patients worldwide each year, for a growing population with comorbidities who exhibit an increased risk of bleeding with DOAC treat…