On maximal subgroups of the multiplicative group of a division algebra

This note studies the question whether a multiplicative group of a division ring has a maximal subgroup. It is published in J. Algebra. This is a reputable journal in the subject algebra. Most of submitted papers from 5* schools in RAE was in this journal.

A distributed contention-vector division multiple access (D-CVDMA) protocol for wireless networks

Traditional Time Division Multiple Access (TDMA) protocol provides deterministic periodic collision free data transmissions. However, TDMA lacks flexibility and exhibits low efficiency in dynamic environments such as wireless LANs. On the other hand contention-based MAC protocols such as the IEEE 802.11 DCF are adaptive to network dynamics but are generally inefficient in heavily loaded or large networks. To take advantage of the both types of protocols, a D-CVDMA protocol is proposed. It is based on the k-round elimination contention (k-EC) scheme, which provides fast contention resolution for Wireless LANs. D-CVDMA uses a contention mechanism to achieve TDMA-like collision-free data transmissions, which does not need to reserve time slots for forthcoming transmissions. These features make the D-CVDMA robust and adaptive to network dynamics such as node leaving and joining, changes in packet size and arrival rate, which in turn make it suitable for the delivery of hybrid traffic including multimedia and data content. Analyses and simulations demonstrate that D-CVDMA outperforms the IEEE 802.11 DCF and k-EC in terms of network throughput, delay, jitter, and fairness.

A meta-analysis of latitudinal variations in life-history traits of roach, Rutilus rutilus, over its geographical range: linear or non-linear relationships?

1. We collated information from the literature on life history traits of the roach (a generalist freshwater fish), and analysed variation in absolute fecundity, von Bertalanffy parameters, and reproductive lifespan in relation to latitude, using both linear and non-linear regression models. We hypothesized that because most life history traits are dependent on growth rate, and growth rate is non-linearly related with temperature, it was likely that when analysed over the whole distribution range of roach, variation in key life history traits would show non-linear patterns with latitude.

Promoting mental health in Northern Ireland: addressing division, inequality and stigma

This article provides an overview of the literature on the impact of ‘the Troubles’ on mental health in Nor thern Ireland. It identifies three main phases of professional and policy response from concerns about the effects of the violence in the early 1970s, through many years of collective denial and neglect, until acknowledgment, following the Good Friday Agreement in 1998 (Nor thern Ireland Office, 1998), of high levels of trauma and unmet need. The issues of inequality and stigma are also considered and it is argued that peace is necessary but insufficient for promoting mental health. The development of mental health services in Nor thern Ireland and the relatively recent focus on promoting mental health are also outlined and examined. It is suggested that attempts to address the needs arising as a result of ‘the Troubles’ and more general mental health promotion strategies have, to some extent, developed in parallel and that it may be impor tant to integrate these effor ts. The relative under-development of mental health services, the comprehensive Bamford Review of Mental Health and Learning Disability (2005; 2006) and the positive approach of the Public Health Agency mean that, even in the current economic climate, there are great oppor tunities for progress. Routine screening, in primary care and mental health services for trauma, including Troubles-related trauma, is recommended to identify and address these issues on an individual level. It is also argued, however, that more substantial political change is needed to effectively address societal division, inequality and stigma to the benefit of all.

Geographical variation of presentation at diagnosis of Type I diabetes in children: the EURODIAB Study

Aims/hypothesis. We aimed to describe the frequency and degree of diabetic ketoacidosis in children across Europe at the time of diagnosis of Type I (insulin-dependent) diabetes mellitus and to determine if factors such as age and geographical region contribute to the risk of diabetic ketoacidosis.

Sexual division of antibacterial resource defence in breeding burying beetles, Nicrophorus vespilloides

A key component of parental care involves defending resources destined for offspring from a diverse array of potential interspecific competitors, such as social parasites, fungi and bacteria. 2. Just as with other aspects of parental care, such as offspring provisioning or brood defence, sexual conflict between parents may arise over how to share the costs of this form of care. There has been little previous work, however, to investigate how this particular burden might be shared. 3. Here, we describe a hitherto uncharacterized form of parental care in burying beetles Nicrophorus vespilloides, a species which prepares carrion for its young and faces competition from microbes for this resource. We found that parents defend the carcass with antibacterial anal exudates, and that the antibacterial activity of these exudates is only upregulated following the discovery of a corpse. At the same time, phenoloxidase activity in the anal exudates is downregulated, indicating parallels with the internal insect immune system. 4. In unmanipulated breeding pairs, females had higher antibacterial activity in their anal exudates than males, suggesting sex-specific roles in this aspect of parental care. 5. When we experimentally widowed males, we found that they increased levels of antibacterial activity in their anal exudates. Experimentally widowing females, however, led them to decrease levels of antibacterial activity in their anal exudates. Widowed beetles of each sex thus produced anal exudates of comparable antibacterial activity. We suggest that this flexible division of antibacterial activity may be coordinated by Juvenile Hormone. © 2009 British Ecological Society.

Genetic diversity of liver flukes (Fasciola hepatica) from Eastern Europe.

The genetic diversity of liver fluke populations in three different countries from Eastern Europe (Greece, Bulgaria, and Poland) in comparison with available data from other countries was determined. Specifically, SNPs from regions of two nuclear genes, 28S rDNA, ß-tubulin 3 and an informative region of the mitochondrial genome were examined. Two major lineages for the 28S rDNA gene based on the highly polymorphic 105th nucleotide position were found. These lineages were widely and almost equally spread not only through the countries studied but also in other investigated geographical areas. Two basic lineages and additional haplotypes were defined for the mtDNA gene region, consisting of the cytochrome c oxidase subunit III gene, transfer RNA histidine gene and cytochome b gene. The basic lineages were observed within Greek, Bulgarian, and Polish Fasciola hepatica populations but the distribution of additional haplotypes differed between the populations from the three countries. For the ß-tubulin 3 gene multiple polymorphic sites were revealed but no explicit clades. The SNPs were spread unequally in all studied geographical regions with an evident distinction between the Greek and Polish specimens. Additional genotypes for the 28S rDNA region as well as haplotypes of the mtDNA region that were typical for the Greek or Polish populations were observed. Significant polymorphisms for ß-tubulin 3 gene were displayed with decreasing percentage of presence within populations from Greece to Poland. There was an amino acid substitution in ß-tubulin 3 protein found only among Polish specimens. It is hypothesized that genotypic differences between Greek, Bulgarian, and Polish liver fluke populations are due to territorial division and genetic drift in past epochs.

SK1 of graded division algebras

The reduced Whitehead group $\SK$ of a graded division algebra graded by a torsion-free abelian group is studied. It is observed that the computations here are much more straightforward than in the non-graded setting. Bridges to the ungraded case are then established by the following two theorems: It is proved that $\SK$ of a tame valued division algebra over a henselian field coincides with $\SK$ of its associated graded division algebra. Furthermore, it is shown that $\SK$ of a graded division algebra is isomorphic to $\SK$ of its quotient division algebra. The first theorem gives the established formulas for the reduced Whitehead group of certain valued division algebras in a unified manner, whereas the latter theorem covers the stability of reduced Whitehead groups, and also describes $\SK$ for generic abelian crossed products.