7,568 research outputs found
Recommended from our members
Honour based violence and the multi-agency approach in Nottingham: response of local agencies to honour based violence
The focus of the research was to gain an understanding of the current levels of HBV in Nottingham and the nature of the multi-agency response. The main aim of the research was to gain an understanding of practitioners' work with a range of issues relating to honour based violence (HBV)within partnership agencies. The revised Violence Against Women and Girls Strategy Action Plan published by the government in2010 (Home Office, 2010) gave precedence to a co-ordinated approach to ending all forms of violence against women including HBV and forced marriage
Hyperon production in near threshold nucleon-nucleon collisions
We study the mechanism of the associated Lambda-kaon and Sigma-kaon
production in nucleon-nucleon collisions over an extended range of near
threshold beam energies within an effective Lagrangian model, to understand of
the new data on pp --> p Lambda K+ and pp --> p Sigma0 K+ reactions published
recently by the COSY-11 collaboration. In this theory, the hyperon production
proceeds via the excitation of N*(1650), N*(1710), and N*(1720) baryonic
resonances. Interplay of the relative contributions of various resonances to
the cross sections, is discussed as a function of the beam energy over a larger
near threshold energy domain. Predictions of our model are given for the total
cross sections of pp --> p Sigma+K0, pp --> n Sigma+K+, and pn --> n Lambda K+
reactions.Comment: 16 pages, 4 figures, one new table added and dicussions are updated,
version accepted for publication by Physical Review
Sampling rare switching events in biochemical networks
Bistable biochemical switches are ubiquitous in gene regulatory networks and
signal transduction pathways. Their switching dynamics, however, are difficult
to study directly in experiments or conventional computer simulations, because
switching events are rapid, yet infrequent. We present a simulation technique
that makes it possible to predict the rate and mechanism of flipping of
biochemical switches. The method uses a series of interfaces in phase space
between the two stable steady states of the switch to generate transition
trajectories in a ratchet-like manner. We demonstrate its use by calculating
the spontaneous flipping rate of a symmetric model of a genetic switch
consisting of two mutually repressing genes. The rate constant can be obtained
orders of magnitude more efficiently than using brute-force simulations. For
this model switch, we show that the switching mechanism, and consequently the
switching rate, depends crucially on whether the binding of one regulatory
protein to the DNA excludes the binding of the other one. Our technique could
also be used to study rare events and non-equilibrium processes in soft
condensed matter systems.Comment: 9 pages, 6 figures, last page contains supplementary informatio
Oscillating epidemics in a dynamic network model: stochastic and mean-field analysis
An adaptive network model using SIS epidemic propagation with link-type-dependent link activation and deletion is considered. Bifurcation analysis of the pairwise ODE approximation and the network-based stochastic simulation is carried out, showing that three typical behaviours may occur; namely, oscillations can be observed besides disease-free or endemic steady states. The oscillatory behaviour in the stochastic simulations is studied using Fourier analysis, as well as through analysing the exact master equations of the stochastic model. By going beyond simply comparing simulation results to mean-field models, our approach yields deeper insights into the observed phenomena and help better understand and map out the limitations of mean-field models
Lack of self-averaging in neutral evolution of proteins
We simulate neutral evolution of proteins imposing conservation of the
thermodynamic stability of the native state in the framework of an effective
model of folding thermodynamics. This procedure generates evolutionary
trajectories in sequence space which share two universal features for all of
the examined proteins. First, the number of neutral mutations fluctuates
broadly from one sequence to another, leading to a non-Poissonian substitution
process. Second, the number of neutral mutations displays strong correlations
along the trajectory, thus causing the breakdown of self-averaging of the
resulting evolutionary substitution process.Comment: 4 pages, 2 figure
Floristic Composition and Natural History Characteristics of Dry Forests in the Pacific
We compare the floristic composition of tropical dry forests at the stand level using Gentry's transect method (0.1 ha) in some of the largest and highest-quality remaining fragments in the Pacific (Hawai'i, 15 sites; Fiji, 9; the Marianas, 3; the Marquesas, 6; New Caledonia, 7) and compare results with neotropical dry forests. A total of 299 species or morphospecies =2.5 cm diameter at breast height were identified from all 40 sites in the Pacific. Rubiaceae (28 spp.), Euphorbiaceae (25 spp.), Fabaceae (23 spp.), Sapindaceae (18 spp.), and Myrtaceae (17 spp.) were the most speciose families in Pacific dry forest; however, no family dominated across regions in the Pacific. The most common species by frequency and density in each region were native with the exception of Hawai'i, which contains a high number of nonnative species. Observed and estimated (Chao 2) levels of native species richness show that New Caledonia and Fiji contain the highest species richness followed by Hawai'i, the Marianas, and the Marquesas. There is very little overlap at the native species level among regions, with Hawaiian dry forests the most dissimilar at the native species, genus, and family level and New Caledonia and Fiji the most similar. Unlike mainland neotropical dry forest, dry forests in the Pacific contain very few deciduous species and a low proportion of wind-dispersed species.There is a high proportion of dioecious species in Hawai'i, which is similar to the neotropics; however, other Pacific regions have fewer dioecious species
Spider webs, stable isotopes and molecular gut content analysis: Multiple lines of evidence support trophic niche differentiation in a community of Hawaiian spiders
1.Adaptive radiations are typically characterized by niche partitioning among their constituent species. Trophic niche partitioning is particularly important in predatory animals, which rely on limited food resources for survival.2.We test for trophic niche partitioning in an adaptive radiation of Hawaiian Tetragnatha spiders, which have diversified in situ on the Hawaiian Islands. We focus on a community of nine species belonging to two different clades, one web-building and the other actively hunting, which co-occur in wet forest on East Maui. We hypothesize that trophic niches differ significantly both: (a) among species within a clade, indicating food resource partitioning, and (b) between the two clades, corresponding to their differences in foraging strategy.3.To assess niches of the spider species, we measure: (a) web architecture, the structure of the hunting tool, and (b) site choice, the physical placement of the web in the habitat. We then test whether differences in these parameters translate into meaningful differences in trophic niche by measuring (c) stable isotope signatures of carbon and nitrogen in the spiders\u27 tissues, and (d) gut content of spiders based on metabarcoding data.4.We find significant interspecific differences in web architecture and site choice. Importantly, these differences are reflected in stable isotope signatures among the five web-building species, as well as significant isotopic differences between web-builders and active hunters. Gut content data also show interspecific and inter-clade differences. Pairwise overlaps of web architecture between species are positively correlated with overlaps of isotopic signature.5.Our results reveal trophic niche partitioning among species within each clade, as well as between the web-building and actively hunting clades. Based on the correlation between web architecture and stable isotopes, it appears that the isotopic signatures of spiders\u27 tissues are influenced by architectural differences among their webs. Our findings indicate an important link between web structure, microhabitat preference and diet in the Hawaiian Tetragnatha
- âŠ