1,208 research outputs found
Moral reasoning and homosexuality: the acceptability of arguments about lesbian and gay issues
In the political arena, lesbian and gay issues have typically been contested on grounds of human rights, but with variable success. Using a moral developmental framework, the purpose of this study was to explore preferences for different types of moral arguments when thinking about moral dilemmas around lesbian and gay issues. The analysis presented here comprised data collected from 545 students at UK universities, who completed a questionnaire, part of which comprised a moral dilemma task. Findings of the study showed that respondents do not apply moral reasoning consistently, and do not (clearly) favour human rights reasoning when thinking about lesbian and gay issues. Respondents tended to favour reasoning supporting existing social structures and frameworks, therefore this study highlights the importance of structural change in effecting widespread attitude change in relation to lesbian and gay rights issues. The implications of the findings for moral education are also discussed.</p
Exponential martingales and changes of measure for counting processes
We give sufficient criteria for the Dol\'eans-Dade exponential of a
stochastic integral with respect to a counting process local martingale to be a
true martingale. The criteria are adapted particularly to the case of counting
processes and are sufficiently weak to be useful and verifiable, as we
illustrate by several examples. In particular, the criteria allow for the
construction of for example nonexplosive Hawkes processes as well as counting
processes with stochastic intensities depending on diffusion processes
In-situ velocity imaging of ultracold atoms using slow--light
The optical response of a moving medium suitably driven into a slow-light
propagation regime strongly depends on its velocity. This effect can be used to
devise a novel scheme for imaging ultraslow velocity fields. The scheme turns
out to be particularly amenable to study in-situ the dynamics of collective and
topological excitations of a trapped Bose-Einstein condensate. We illustrate
the advantages of using slow-light imaging specifically for sloshing
oscillations and bent vortices in a stirred condensate
Modelling mucociliary clearance
Mathematical modelling of the fluid mechanics of mucociliary clearance (MCC) is reviewed and future challenges for researchers are discussed. The morphology of the bronchial and tracheal airway surface liquid (ASL) and ciliated epithelium are briefly introduced. The cilia beat cycle, beat frequency and metachronal coordination are described, along with the rheology of the mucous layer. Theoretical modelling of MCC from the late 1960s onwards is reviewed, and distinctions between ‘phenomenological’, ‘slender body theory’ and recent ‘fluid–structure interaction’ models are explained.\ud
\ud
The ASL consists of two layers, an overlying mucous layer and underlying watery periciliary layer (PCL) which bathes the cilia. Previous models have predicted very little transport of fluid in the PCL compared with the mucous layer. Fluorescent tracer transport experiments on human airway cultures conducted by Matsui et al. [Matsui, H., Randell, S.H., Peretti, S.W., Davis, C.W., Boucher, R.C., 1998. Coordinated clearance of periciliary liquid and mucus from airway surfaces. J. Clin. Invest. 102 (6), 1125–1131] apparently showed equal transport in both the PCL and mucous layer. Recent attempts to resolve this discrepancy by the present authors are reviewed, along with associated modelling findings. These findings have suggested new insights into the interaction of cilia with mucus due to pressure gradients associated with the flat PCL/mucus interface. This phenomenon complements previously known mechanisms for ciliary propulsion. Modelling results are related to clinical findings, in particular the increased MCC observed in patients with pseudohypoaldosteronism. Recent important advances by several groups in modelling the fluid–structure interaction by which the cilia movement and fluid transport emerge from specification of internal mechanics, viscous and elastic forces are reviewed. Finally, we discuss the limitations of existing work, and the challenges for the next generation of models, which may provide further insight into this complex and vital system
ASTEC -- the Aarhus STellar Evolution Code
The Aarhus code is the result of a long development, starting in 1974, and
still ongoing. A novel feature is the integration of the computation of
adiabatic oscillations for specified models as part of the code. It offers
substantial flexibility in terms of microphysics and has been carefully tested
for the computation of solar models. However, considerable development is still
required in the treatment of nuclear reactions, diffusion and convective
mixing.Comment: Astrophys. Space Sci, in the pres
pQCD Physics of multiparton interactions
We study production of two pairs of jets in %hard hadron--hadron collisions
in view of extracting contribution of {\em double hard interactions} of three
and four partons (, ). Such interactions, in spite of being power
suppressed at the level of the total cross section, become comparable with the
standard hard collisions of two partons, , in the {\em back-to-back
kinematics} when the transverse momentum imbalances of two pairing jets are
relatively small.
We express differential and total cross sections for two-dijet production in
double parton collisions through the generalized two-parton distributions,
GPDs \cite{BDFS1}, that contain large-distance two-parton correlations of
non-perturbative origin as well as small-distance correlations due to parton
evolution. We find that these large- and small-distance correlations
participate in different manner in 4-jet production, and treat them in the
leading logarithmic approximation of pQCD that resums collinear logarithms in
all orders.
A special emphasis is given to double hard interaction processes that
occur as an interplay between large- and short-distance parton correlations and
were not taken into consideration by approaches inspired by the parton model
picture. We demonstrate that the mechanism, being of the same order in
\as as the process, turns out to be {\em geometrically enhanced}
compared to the latter and should contribute significantly to 4-jet production.
The framework developed here takes into systematic consideration perturbative
evolution of GPDs. It can be used as a basis for future analysis of
NLO corrections to multi-parton interactions (MPI) at LHC and Tevatron
colliders, in particular for improving evaluation of QCD backgrounds to new
physics searches.Comment: 16 pages,4 figures Improved presentation; list of references
reworked; qualitative estimate of the magnitude of different contributions in
the beck-to- back region correcte
RNA-seq and Tn-seq reveal fitness determinants of vancomycin-resistant Enterococcus faecium during growth in human serum
BACKGROUND: The Gram-positive bacterium Enterococcus faecium is a commensal of the human gastrointestinal tract and a frequent cause of bloodstream infections in hospitalized patients. The mechanisms by which E. faecium can survive and grow in blood during an infection have not yet been characterized. Here, we identify genes that contribute to growth of E. faecium in human serum through transcriptome profiling (RNA-seq) and a high-throughput transposon mutant library sequencing approach (Tn-seq). RESULTS: We first sequenced the genome of E. faecium E745, a vancomycin-resistant clinical isolate, using a combination of short- and long read sequencing, revealing a 2,765,010 nt chromosome and 6 plasmids, with sizes ranging between 9.3 kbp and 223.7 kbp. We then compared the transcriptome of E. faecium E745 during exponential growth in rich medium and in human serum by RNA-seq. This analysis revealed that 27.8% of genes on the E. faecium E745 genome were differentially expressed in these two conditions. A gene cluster with a role in purine biosynthesis was among the most upregulated genes in E. faecium E745 upon growth in serum. The E. faecium E745 transposon mutant library was then used to identify genes that were specifically required for growth of E. faecium in serum. Genes involved in de novo nucleotide biosynthesis (including pyrK_2, pyrF, purD, purH) and a gene encoding a phosphotransferase system subunit (manY_2) were thus identified to be contributing to E. faecium growth in human serum. Transposon mutants in pyrK_2, pyrF, purD, purH and manY_2 were isolated from the library and their impaired growth in human serum was confirmed. In addition, the pyrK_2 and manY_2 mutants were tested for their virulence in an intravenous zebrafish infection model and exhibited significantly attenuated virulence compared to E. faecium E745. CONCLUSIONS: Genes involved in carbohydrate metabolism and nucleotide biosynthesis of E. faecium are essential for growth in human serum and contribute to the pathogenesis of this organism. These genes may serve as targets for the development of novel anti-infectives for the treatment of E. faecium bloodstream infections
Square to stripe transition and superlattice patterns in vertically oscillated granular layers
We investigated the physical mechanism for the pattern transition from square
lattice to stripes, which appears in vertically oscillating granular layers. We
present a continuum model to show that the transition depends on the
competition between inertial force and local saturation of transport. By
introducing multiple free-flight times, this model further enables us to
analyze the formation of superlattices as well as hexagonal lattice
Определение оптимальных параметров источника рентгеновского излучения на базе малогабаритного ускорителя электронов
Проведено моделирование спектров рентгеновского излучения, генерируемого электронами с энергией 4…10 МэВ в мишенях из различных материалов и разной толщины. Определены оптимальные параметры мишени-конвертора для использования ее в медицинских источниках монохроматического рентгеновского излучения на базе малогабаритных электронных ускорителей. Проведены оценки интенсивности излучения и сравнение источников на базе разных ускорителей
The molecular epidemiology of human immunodeficiency virus type 1 in six cities in Britain and Ireland
The authors sequenced the p17 coding regions of the gag gene from 211 patients infected either through injecting drug use (IDU) or by sexual intercourse between men from six cities in Scotland, N. England, N. Ireland, and the Republic of Ireland. All sequences were of subtype 5. Phylogenetic analysis revealed substantial heterogeneity in the sequences from homosexual men. In contrast, sequence from over 80% of IDUs formed a relatively tight cluster, distinct both from those of published isolates and of the gay men. There was no large-scale clustering of sequences by city in either risk group, although a number of close associations between pairs of individuals were observed. From the known date of the HIV-1 epidemic among IDUs in Edinburgh, the rate of sequence divergence at synonymous sites is estimated to be about 0.8%. On this basis it has been estimated that the date of divergence of the sequences among homosexual men to be about 1975, which may correspond to the origin of the B subtype epidemic
- …