bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential effects of landscape and management on diversity and density of ground‐dwelling farmland spiders
Authors: SCHMIDT MARTIN H. , ROSCHEWITZ INDRA , THIES CARSTEN , TSCHARNTKE TEJA
Published: April 2005

The distribution and abundance of animals are influenced by factors at both local and wider landscape scales. Natural enemies of pests in arable fields often immigrate from the surrounding landscape, and are also influenced by local management practices. Thus, landscape diversification and farming methods may both enhance farmland biodiversity, but their relative roles and possible interactions have been little explored.

The relationships of ground‐dwelling spiders (Araneae) to landscape features and to organic agriculture were studied in 12 pairs of organic vs. conventional fields of winter wheat Triticum aestivum along a gradient of landscape complexity.

High percentages of non‐crop habitats in the landscape increased local species richness of spiders from 12 to 20 species, irrespective of local management. This indicates that larger species pools are sustained in complex landscapes, where there is higher availability of refuge and overwintering habitats.

Organic agriculture did not increase the number of spider species, but enhanced spider density by 62%. Additionally, spider density was positively related to the percentage of non‐crop habitats in the surrounding landscape, but only in conventional fields.

Synthesis and applications. The species richness of ground‐dwelling spiders in crop fields was linked to large‐scale landscape complexity, while spider densities responded to local management practices. Organic agriculture benefits farmland spiders and augments the numbers of predatory spiders, thereby contributing to pest control. However, measures to conserve species richness must also take landscape‐scale factors into account. Complex landscapes including perennial non‐crop habitats should be preserved or restored to achieve high levels of spider diversity.
Why high seed densities within buried mesh bags may overestimate depletion rates of soil seed banks
Authors: VAN MOURIK TOM A. , STOMPH TJEERD J. , MURDOCH ALISTAIR J.
Published: April 2005

Estimates of seed bank depletion rates are essential for modelling and management of plant populations. The seed bag burial method is often used to measure seed mortality in the soil. However, the density of seeds within seed bags is higher than densities in natural seed banks, which may elevate levels of pathogens and influence seed mortality. The aim of this study was to quantify the effects of fungi and seed density within buried mesh bags on the mortality of seeds. Striga hermonthica was chosen as the study species because it has been widely studied but different methods for measuring seed mortality in the soil have yielded contradictory estimates.

Seed bags were buried in soil and exhumed at regular time intervals to monitor mortality of the seeds in three field experiments during two rainy seasons. The effect of fungal activity on seed mortality was evaluated in a fungi exclusion experiment. Differences in seed‐to‐seed interaction were obtained by using two and four densities within the seed bags in consecutive years. Densities were created by mixing 1000 seeds with 0, 10, 100 or 1000 g of coarse sand.

The mortality rate was significantly lower when fungi were excluded, indicating the possible role of pathogenic fungi.

Decreasing the density of seeds in bags significantly reduced seed mortality, most probably because of decreased seed‐to‐seed contamination by pathogenic fungi.

Synthesis and applications. Models of plant populations in general and annual weeds in particular often use values from the literature for seed bank depletion rates. These depletion rates have often been estimated by the seed bag burial method, yet seed density within seed bags may be unrealistically high. Consequently, estimates of seed mortality rates may be too high because of an overestimation of the effects of soil or seed‐borne pathogens. Species that have been classified from such studies as having short‐lived seed banks may need to be re‐assessed using realistic densities either within seed bags or otherwise. Similarly, models of seed bank dynamics based on such overestimated depletion rates may lead to incorrect conclusions regarding the seed banks and, perhaps, the management of weeds and rare species.
The history and geography of diversification within the butterfly genus Lycaeides in North America
Authors: NICE CHRIS C. , ANTHONY NICOLA , GELEMBIUK GREG , RATERMAN DENISE , FFRENCH‐CONSTANT RICHARD
Published: April 2005

The Lycaeides butterfly species complex in North America consists of two nominal, morphologically defined species. These butterflies are ecologically diverse and appear to be distributed as a geographically complex mosaic of locally differentiated populations that may be undergoing adaptive radiation. We asked whether patterns of molecular genetic variation within the species complex are congruent with currently recognized morphological species and whether the distribution of molecular variation is consistent with the hypothesis that Pleistocene climate changes contributed to the process of differentiation within the genus. Variation in the form of the genitalia from 726 males from 59 populations clearly distinguishes both species with only six populations containing morphologically intermediate or ambiguous individuals. However, partitioning of molecular variance in a 236 bp section of the mitochondrial AT‐rich region from 628 individuals (57 populations) surveyed using single strand conformation polymorphism analysis (SSCP) indicates that only 26% of the total genetic variation is distributed along nominal species boundaries as defined by morphology. Instead, three phylogeographical groups were detected, represented by three major haplotype clades, which account for 90% of the total genetic variance. Pleistocene glaciations appear to have fostered divergence during glacial maxima, while postglacial range expansions created opportunities for gene exchange and reticulation along suture zones between geographical groups. Data presented here allow us to make inferences about the history of the species complex. However, evidence of ancestral polymorphism and reticulation limit our ability to define species boundaries based on mitochondrial DNA sequence variation.
Postglacial colonization of the Tibetan plateau inferred from the matrilineal genetic structure of the endemic red‐necked snow finch, Pyrgilauda ruficollis
Authors: QU YAN HUA , ERICSON PER G. P. , LEI FU MIN , LI SHOU HSIEN
Published: April 2005

Most phylogeographical studies of postglacial colonization focus on high latitude locations in the Northern Hemisphere. Here, we studied the phylogeographical structure of the red‐necked snow finch Pyrgilauda ruficollis, an endemic species of the Tibetan plateau. We analysed 879 base pairs (bp) of the mitochondrial cytochrome b gene and 529 bp of the control region in 41 birds from four regional groups separated by mountain ranges. We detected 34 haplotypes, 31 of which occurred in a single individual and only three of which were shared among sampling sites within regional groups or among regional groups. Haplotype diversity was high (h = 0.94); nucleotide diversity was low (ð = 0.00415) and genetic differentiation was virtually non‐existent. Analyses of mismatch distributions and geographically nested clades yielded results consistent with contiguous range expansion, and the expansion times were estimated as 0.07–0.19 million years ago (Ma). Our results suggest that P. ruficollis colonized the Tibetan plateau after the extensive glacial period (0.5–0.175 Ma), expanding from the eastern margin towards the inner plateau. Thus, in contrast to many of the postglacial phylogeographical structures known at high latitudes, this colonization occurred without matrilineal population structuring. This might be due to the short glacial cycles typical of the Tibetan plateau, adaptation of P. ruficollis to cold conditions, or refugia and colonized habitat being semicontinuous and thus promoting population mixing.
Genetic variability and phylogeography of the invasive zebra mussel,Dreissena polymorpha(Pallas)
Authors: ASTANEI IULIAN , GOSLING ELIZABETH , WILSON JIM , POWELL EITHNE
Published: April 2005

The zebra mussel,Dreissena polymorpha(Pallas), a bivalve species originally native to the Black and Caspian seas, has invaded Ireland in the last decade. Five microsatellite loci were used to investigate genetic diversity and population structure in 10 populations across Europe (Ireland, UK, the Netherlands and Romania) and the Great Lakes (Lake Ontario and Lake St Clair). Levels of allelic diversity and mean expected heterozygosity were high for all populations (mean number of alleles/locus andHEwere 10–15.2 and 0.79–0.89, respectively). High levels of polymorphism observed in Irish populations suggest that the Irish founder population(s) were large and/or several introductions took place after foundation. Significant deficits of heterozygotes were recorded for all populations, and null alleles were the most probable factor contributing to these deficits. Pairwise comparisons using Fisher exact tests andFSTvalues revealed little genetic differentiation between Irish populations. The UK sample was not significantly differentiated from the Irish samples, most probably reflecting an English origin for Irish zebra mussels. No significant differentiation was detected between the two Great Lakes populations. Our data support a northwest rather than a central or east European source for North American zebra mussels.
The effects of habitat fragmentation on the social kin structure and mating system of the agile antechinus, Antechinus agilis
Authors: BANKS S. C. , WARD S. J. , LINDENMAYER D. B. , FINLAYSON G. R. , LAWSON S. J. , TAYLOR A. C.
Published: April 2005

Habitat fragmentation is one of the major contributors to the loss of biodiversity worldwide. However, relatively little is known about its more immediate impacts on within‐patch population processes such as social structure and mating systems, whose alteration may play an important role in extinction risk. We investigated the impacts of habitat fragmentation due to the establishment of an exotic softwood plantation on the social kin structure and breeding system of the Australian marsupial carnivore, Antechinus agilis. Restricted dispersal by males in fragmented habitat resulted in elevated relatedness among potential mates in populations in fragments, potentially increasing the risk of inbreeding. Antechinus agilis nests communally in tree hollows; these nests are important points for social contact between males and females in the mating season. In response to elevated relatedness among potential mates in fragmented habitat, A. agilis significantly avoided sharing nests with opposite‐sex relatives in large fragment sites (but not in small ones, possibly due to limited nest locations and small population sizes). Because opposite‐sex individuals shared nests randomly with respect to relatedness in unfragmented habitat, we interpreted the phenomenon in fragmented habitat as a precursor to inbreeding avoidance via mate choice. Despite evidence that female A. agilis at high inbreeding risk selected relatively unrelated mates, there was no overall increased avoidance of related mates by females in fragmented habitats compared to unfragmented habitats. Simulations indicated that only dispersal, and not nonrandom mating, contributed to inbreeding avoidance in either habitat context. However, habitat fragmentation did influence the mating system in that the degree of multiple paternity was reduced due to the reduction in population sizes and population connectivity. This, in turn, reduced the number of males available to females in the breeding season. This suggests that in addition to the obvious impacts of reduced recruitment, patch recolonization and increased genetic drift, the isolation of populations in habitat patches may cause changes in breeding behaviour that contribute to the negative impacts of habitat fragmentation.
Multiple paternity in a natural population of a salamander with long‐term sperm storage
Authors: ADAMS ERIKA M. , JONES ADAM G. , ARNOLD STEVAN J.
Published: April 2005

Sperm competition appears to be an important aspect of any mating system in which individual female organisms mate with multiple males and store sperm. Postcopulatory sexual selection may be particularly important in species that store sperm throughout long breeding seasons, because the lengthy storage period may permit extensive interactions among rival sperm. Few studies have addressed the potential for sperm competition in species exhibiting prolonged sperm storage. We used microsatellite markers to examine offspring paternity in field‐collected clutches of the Ocoee salamander (Desmognathus ocoee), a species in which female organisms store sperm for up to 9 months prior to fertilization. We found that 96% of clutches were sired by multiple males, but that the majority of females used sperm from only two or three males to fertilize their eggs. The high rate of multiple mating by females suggests that sperm competition is an important aspect of this mating system. Comparison of our data with those of other parentage studies in salamanders and newts reveals that multiple mating may be common in urodele amphibians. Nevertheless, the number of males siring offspring per clutch in D. ocoee did not differ appreciably from that in other species of urodeles with shorter storage periods.
Habitat specialization and adaptive phenotypic divergence of anuran populations
Authors: VAN BUSKIRK J. , ARIOLI M.
Published: April 2005

We tested for adaptive population structure in the frog Rana temporaria by rearing tadpoles from 23 populations in a common garden experiment, with and without larval dragonfly predators. The goal was to compare tadpole phenotypes with the habitats of their source ponds. The choice of traits and habitat variables was guided by prior information about phenotypic function. There were large differences among populations in life history, behaviour, morphological shape, and the predator‐induced plasticities in most of these. Body size and behaviour were correlated with predation risk in the source pond, in agreement with adaptive population divergence. Tadpoles from large sunny ponds were morphologically distinct from those inhabiting small woodland ponds, although here an adaptive explanation was unclear. There was no evidence that plasticity evolves in populations exposed to more variable environments. Much among‐population variation in phenotype and plasticity was not associated with habitat, perhaps reflecting rapid changes in wetland habitats.
Macroevolutionary trends in the Dinosauria: Cope's rule
Authors: HONE D. W. E. , KEESEY T. M. , PISANI D. , PURVIS A.
Published: April 2005

Cope's rule is the tendency for body size to increase over time along a lineage. A set of 65 phylogenetically independent comparisons, between earlier and later genera, show that Cope's rule applied in dinosaurs: later genera were on average about 25% longer than the related earlier genera to which they were compared. The tendency for size to increase was not restricted to a particular clade within the group, nor to a particular time within its history. Small lineages were more likely to increase in size, and large lineages more likely to decrease: this pattern may indicate an intermediate optimum body size, but can also be explained as an artefact of data error. The rate of size increase estimated from the phylogenetic comparisons is significantly higher than the rate seen across the fauna as a whole. This difference could indicate that within‐lineage selection for larger size was opposed by clade selection favouring smaller size, but data limitations mean that alternative explanations (which we discuss) cannot be excluded. We discuss ways of unlocking the full potential usefulness of phylogenies for studying the dynamics of evolutionary trends.
The benefits of polyandry in the free‐spawning polychaete Galeolaria caespitosa
Authors: MARSHALL D. J. , EVANS J. P.
Published: April 2005

In many species, females are thought to benefit from polyandry due to the reduced risks of fertilization by genetically incompatible sperm. However, few studies that have reported such benefits have directly attributed variation in female reproductive success to the interacting effects of males and females at fertilization. In this paper, we determine whether male × female interactions influence fertilization in vitro in the free‐spawning, sessile polychaete Galeolaria caespitosa. Furthermore, we determined whether polyandry results in direct fertilization benefits for females by experimentally manipulating the number of males contributing towards staged spawning events. To test for male × female interaction effects we performed an initial experiment that crossed seven males with six females (in all 42 combinations), enabling us to assess fertilization rates for each specific male–female pairing and attribute variation in fertilization success to males, females and their interaction. This initial experiment revealed a strong interaction between males and females at fertilization, confirming that certain male–female combinations were more compatible than others. A second experiment tested the hypothesis that polyandry enhances female reproductive success by exposing each female's eggs to either a single male's sperm (monandry) or the sperm from three males simultaneously (polyandry). We performed this second experiment at two ecologically relevant sperm concentrations. This latter experiment revealed a strong fertilization benefit of polyandry, independent of the effects of sperm concentration (which were also significant). We suggest that these direct fertilization gains arising from polyandry will constitute an important source of selection on females to mate multiply in nature.
Hybridization and invasiveness in the freshwater snail Melanoides tuberculata: hybrid vigour is more important than increase in genetic variance
Authors: FACON B. , JARNE P. , POINTIER J. P. , DAVID P.
Published: April 2005

Many invasive taxa are hybrids, but how hybridization boosts the invasive process remains poorly known. We address this question in the clonal freshwater snail Melanoides tuberculata from Martinique, using three parental and two hybrid lines. We combine an extensive field survey (1990–2003) and a quantitative genetic experiment to show that hybrid lines have outcompeted their parents in natural habitats, and that this increased invasiveness co‐occurred with pronounced shifts in life‐history traits, such as growth, fecundity and juvenile size. Given the little time between hybrid creation and sampling, and the moderate standing genetic variance for life‐history traits in hybrids, we show that some of the observed trait changes between parents and hybrids were unlikely to arise only by continuous selection. We therefore suggest that a large part of hybrid advantage stems from immediate heterosis upon hybridization.
Duration and Severity of Clinical Signs as Prognostic Indicators in 30 Dogs with Thoracolumbar Disk Disease After Surgical Decompression
Authors: Kazakos G. , Polizopoulou Z. S. , Patsikas M. N. , Tsimopoulos G. , Roubies N. , Dessiris A.
Published: April 2005

The objective of this study was to evaluate the duration and severity of neurological dysfunction as prognostic indicators for the final outcome in 30 dogs with thoracolumbar intervertebral disk disease, treated surgically with hemilaminectomy without concurrent prophylactic fenestration. The lesion localization was assessed comparing plain radiographic, myelographic and surgical findings and success rates were evaluated during case follow‐up. Evidence of a single disk extrusion existed in 17 dogs on survey spinal radiographs, while myelography revealed definite spinal cord compression in 28 cases and was inconclusive in the remaining two cases. Case follow‐up continued for a period ranging from 3 months to 2 years post‐operatively, depending on the degree of neurological dysfunction on presentation and owner compliance. The severity of clinical signs and the interval elapsing prior to decompressive surgery did not correlate with the case outcome, with 12 of 20 dogs (60%) that exhibited the most pronounced neurological dysfunction (paraplegia with or without analgesia) regaining voluntary motor function during the follow‐up period. Recurrences proven to be disk‐related did not occur in any dog throughout the post‐surgical observation period. It was concluded that the time elapsing from loss of motor function and the severity of clinical signs is not an objective method to predict the case outcome.
Conserving biodiversity under climate change: the rear edge matters
Authors: Hampe Arndt , Petit Rémy J.
Published: April 2005

Modern climate change is producing poleward range shifts of numerous taxa, communities and ecosystems worldwide. The response of species to changing environments is likely to be determined largely by population responses at range margins. In contrast to the expanding edge, the low‐latitude limit (rear edge) of species ranges remains understudied, and the critical importance of rear edge populations as long‐term stores of species’ genetic diversity and foci of speciation has been little acknowledged. We review recent findings from the fossil record, phylogeography and ecology to illustrate that rear edge populations are often disproportionately important for the survival and evolution of biota. Their ecological features, dynamics and conservation requirements differ from those of populations in other parts of the range, and some commonly recommended conservation practices might therefore be of little use or even counterproductive for rear edge populations.
Confronting different models of community structure to species‐abundance data: a Bayesian model comparison
Authors: Etienne Rampal S. , Olff Han
Published: April 2005

Species abundances are undoubtedly the most widely available macroecological data, but can we use them to distinguish among several models of community structure? Here we present a Bayesian analysis of species‐abundance data that yields a full joint probability distribution of each model's parameters plus a relatively parameter‐independent criterion, the posterior Bayes factor, to compare these models. We illustrate our approach by comparing three classical distributions: the zero‐sum multinomial (ZSM) distribution, based on Hubbell's neutral model, the multivariate Poisson lognormal distribution (MPLN), based on niche arguments, and the discrete broken stick (DBS) distribution, based on MacArthur's broken stick model. We give explicit formulas for the probability of observing a particular species‐abundance data set in each model, and argue that conditioning on both sample size and species count is needed to allow comparisons between the two distributions. We apply our approach to two neotropical communities (trees, fish). We find that DBS is largely inferior to ZSM and MPLN for both communities. The tree data do not allow discrimination between ZSM and MPLN, but for the fish data ZSM (neutral model) overwhelmingly outperforms MPLN (niche model), suggesting that dispersal plays a previously underestimated role in structuring tropical freshwater fish communities. We advocate this approach for identifying the relative importance of dispersal and niche‐partitioning in determining diversity of different ecological groups of species under different environmental conditions.
Dispersal, spatial scale, and species diversity in a hierarchically structured experimental landscape
Authors: Cadotte Marc W. , Fukami Tadashi
Published: April 2005

Although there has been growing interest in the effect of dispersal on species diversity, much remains unknown about how dispersal occurring at multiple scales influences diversity. We used an experimental microbial landscape to determine whether dispersal occurring at two different scales – among local communities and among metacommunities – affects diversity differently. At the local scale, dispersal initially had a positive effect and subsequently a neutral effect on diversity, whereas at the metacommunity and landscape scales, dispersal showed a consistently negative effect. The timing in which dispersal affected beta diversity also differed sharply between local communities and metacommunities. These patterns were explained by scale‐ and time‐dependent effects of dispersal in allowing spread of species and in removing spatial refuges from predators. Our results suggest that the relative contribution of opposing mechanisms by which dispersal affects diversity changes considerably over time and space in hierarchical landscapes in which dispersal occurs at multiple scales.
Managing ecosystem services: what do we need to know about their ecology?
Authors: Kremen Claire
Published: April 2005

Human domination of the biosphere has greatly altered ecosystems, often overwhelming their capacity to provide ecosystem services critical to our survival. Yet ecological understanding of ecosystem services is quite limited. Previous work maps the supply and demand for services, assesses threats to them, and estimates economic values, but does not measure the underlying role of biodiversity in providing services. In contrast, experimental studies of biodiversity–function examine communities whose structures often differ markedly from those providing services in real landscapes. A bridge is needed between these two approaches. To develop this research agenda, I discuss critical questions and key approaches in four areas: (1) identifying the important ‘ecosystem service providers’; (2) determining the various aspects of community structure that influence function in real landscapes, especially compensatory community responses that stabilize function, or non‐random extinction sequences that rapidly erode it; (3) assessing key environmental factors influencing provision of services, and (4) measuring the spatio‐temporal scale over which providers and services operate. I show how this research agenda can assist in developing environmental policy and natural resource management plans.
Revision of the fruit fly genus Capparimyia (Diptera, Tephritidae)
Authors: De Meyer Marc , Freidberg Amnon
Published: April 2005

Capparimyia Bezzi is revised and eight species recognized, of which four are new: C. aenigma sp. nov., C. maerua sp. nov., C. mirabilis sp. nov., and C. spatulata sp. nov. A lectotype is designated for C. bipustulata (Bezzi, 1923), C. savastani (Martelli) and C. melanaspis (Bezzi). Capparimyia aristata nom. nov. is proposed as a replacement name for Pardalaspis (now Capparimyia) bipustulata Bezzi, 1924 (preoccupied Bezzi, 1923). All species are described or re‐described, with illustrations of mesonotal and wing patterns and male and female terminalia. A key to species is provided. Phylogenetic relationships within the genus are analysed cladistically and considered vis‐à‐vis the relationships between the host plants. Distribution patterns are discussed.
Insights into the acute cerebral metabolic changes associated with childhood diabetes
Authors: Cameron F. J. , Kean M. J. , Wellard R. M. , Werther G. A. , Neil J. J. , Inder T. E.
Published: April 2005

Aims  Type 1 diabetes is a prevalent chronic disease in childhood with the commonest single cause of death being cerebral oedema in the context of diabetic ketoacidosis (DKA). The nature of the alterations in cerebral metabolism that may result in vulnerability to neuronal injury remains unknown. The aim of this study was to analyse the magnetic resonance imaging (MRI) and magnetic resonance spectroscopy (MRS) brain data from eight children with diabetes following acute presentation with hyperglycaemia with or without ketoacidosis, to determine the nature and timing of any alterations in cerebral structure and metabolism.

Methods  This study used MRI and MRS to investigate regional cerebral abnormalities in a small series of diabetic patients with and without DKA. Changes were compared with the clinical and biochemical features of the patients studied.

Results  Our small series of patients all demonstrated abnormal signal changes in the frontal region on fluid attenuated inversion recovery (FLAIR) MR imaging, suggestive of oedema, and spectroscopic abnormalities of increased taurine, myoinositol and glucose levels. The MR abnormalities varied in severity but did not correlate with any clinical or biochemical parameters.

Conclusions  These changes indicate that many diabetic children, particularly at presentation, may have alterations in cerebral metabolism with implications for the pathogenesis and treatment of the cerebral complications of DKA. In addition, our findings suggest that increased taurine may be one of the important differentiating factors in the response of the brain of diabetic children to DKA that may reflect an increase in their vulnerability to cerebral oedema compared with diabetic adults.
Diabetes, hyperglycaemia and mortality in disabled older women: The Women's Health and Ageing Study I
Authors: Blaum C. S. , Volpato S. , Cappola A. R. , Chaves P. , Xue Q. L. , Guralnik J. M. , Fried L. P.
Published: April 2005

Aims  Diabetes is associated with increased mortality in older adults, but the specific contributions of diabetes‐associated clinical conditions and of increasing hyperglycaemia to mortality risk are unknown. We evaluated whether cardiovascular disease, comorbidities, or degree of hyperglycaemia, particularly severe hyperglycaemia, affected diabetes‐related mortality risk in older, disabled women.

Methods  Six‐year mortality follow‐up of a random sample of 576 disabled women (aged 65–101 years), recruited from the Medicare eligibility list in Baltimore (MD, USA). All‐cause and cardiovascular mortality were evaluated by diabetes status: no diabetes; diabetes with mild, moderate, and severe hyperglycaemia [defined by tertiles of glycosylated haemoglobin (GHB) among women with diabetes].

Results  Diabetes with mild, moderate, and severe hyperglycaemia was associated with an increased hazard rate (HR) for all‐cause mortality, even after adjustment for demographics, risks for cardiovascular disease, cardiovascular and non‐cardiovascular conditions, and other known mortality risks. A dose–response effect was suggested [mild hyperglycaemia, HR 1.81, 95% confidence interval (CI) 1.03, 3.17; moderate hyperglycaemia, HR 2.02, 95% CI 1.34, 3.57; severe hyperglycaemia, HR 2.22, 95% CI 1.17, 4.25]. Women with diabetes had a significantly increased HR for non‐cardiovascular death, but not for cardiovascular death, compared with those without diabetes.

Conclusions  Diabetes, whether characterized by mild, moderate or severe hyperglycaemia, appears to be an independent risk factor for excess mortality in older disabled women and this risk may increase with increasing hyperglycaemia. This mortality risk is not completely explained by vascular complications, and involves non‐cardiovascular deaths. Risks and benefits of diabetes management, including glycaemic control and management of vascular and other comorbidities, should be studied in older people with complications and comorbidities.
Inhibition of dipeptidyl peptidase IV activity by oral metformin in Type 2 diabetes
Authors: Lindsay J. R. , Duffy N. A. , McKillop A. M. , Ardill J. , O'Harte F. P. M. , Flatt P. R. , Bell P. M.
Published: April 2005

Aims  Glucagon‐like peptide‐1 (GLP‐1) and gastric inhibitory polypeptide (GIP) are important insulinotropic hormones that enhance the insulin secretory response to feeding. Their potential for treating Type 2 diabetes is limited by short biological half‐life owing to degradation by dipeptidyl peptidase IV (DPP IV). We investigated the acute effects of metformin on DPP IV activity in Type 2 diabetes to elucidate inhibition of DPP IV as a possible mechanism of action.

Methods  Eight fasting subjects with Type 2 diabetes (5M/3F, age 53.1 ± 4.2 years, BMI 36.8 ± 1.8 kg/m2, glucose 8.9 ± 1.2 mmol/l, HbA1c 7.8 ± 0.6%) received placebo or metformin 1 g orally 1 week apart in a random, crossover design.

Results  Following metformin, DPP IV activity was suppressed compared with placebo (AUC0−6 h 3230 ± 373 vs. 5764 ± 504 nmol ml/l, respectively, P = 0.001). Circulating glucose, insulin and total GLP‐1 were unchanged. Metformin also concentration‐dependently inhibited endogenous DPP IV activity in vitro in plasma from Type 2 diabetic subjects.

Conclusion  Oral metformin effectively inhibits DPP IV activity in Type 2 diabetic patients, suggesting that the drug may have potential for future combination therapy with incretin hormones.
Lifetime risk of symptomatic carpal tunnel syndrome in Type 1 diabetes
Authors: Singh R. , Gamble G. , Cundy T.
Published: April 2005

Aims  To determine the lifetime risk of developing symptomatic carpal tunnel syndrome (CTS) in subjects with Type 1 diabetes and to investigate the effect of glycaemic control, body mass index (BMI), gender and age of onset of diabetes.

Methods  One hundred and twenty‐two consecutive subjects with Type 1 diabetes seen by a single investigator, over 1‐year, were questioned about previous surgery for, or current symptoms of CTS. Those with current symptoms were referred for nerve conduction studies (NCS). Those with previous surgery and/or diagnostic NCS were classified as having CTS. Lifetime risk was calculated by the Kaplan–Meier method.

Results  Twenty six out of 122 patients had CTS, 18 of whom (69%) had undergone median nerve decompression surgery. The predicted lifetime risk of CTS reached 85% after 54 years of Type 1 diabetes (95% confidence interval: 72–97%). The duration of diabetes was greater in those who had developed CTS than in those who had not (29 vs. 19 years, P = 0.0001). In those diagnosed with diabetes before the age of 20 there was a lag time of at least 19 years before the development of CTS, whereas patients with later onset of diabetes, began to develop CTS from as early as 5 years diabetes duration. There was no demonstrable effect of glycaemic control, obesity, gender or retinopathy on the appearance of CTS.

Conclusion  The lifetime risk of developing symptomatic CTS with Type 1 diabetes is high, and is related to age and duration of diabetes, but not to the development of microvascular complications.
Rodent bites on the feet of diabetes patients in Tanzania
Authors: Abbas Z. G. , Lutale J. , Archibald L. K.
Published: April 2005

Aim  To characterize the epidemiology of rodent bite foot injuries in patients presenting to a diabetes clinic in Tanzania.

Methods  During July 1998–September 2003, all adult diabetes patients presenting with rodent bite injuries were identified. Follow‐up included antimicrobial therapy and surgery, where appropriate.

Results  All 34 patients with rodent bites had Type 2 diabetes and peripheral neuropathy. Median age was 55.5 years; 62% were male. All bites occurred during sleep. The median time between acquiring the bite and presentation to MNH was 7 (range: 1–17) days. Patients who delayed seeking medical attention were significantly more likely to develop gangrene. Seventeen patients underwent minor or major amputation. Complete healing occurred in 30 (88%) patients; four patients died.

Conclusion  Diabetes patients with peripheral neuropathy are at increased risk of bite injuries in areas with large rodent populations. Preventive efforts should include covering the feet at bedtime, and daily feet examination by patient or relatives.
Genetics of Type 2 diabetes
Authors: Barroso I.
Published: April 2005

Type 2 diabetes (T2D) has become a health‐care problem worldwide, with the rise in disease prevalence being all the more worrying as it not only affects the developed world but also developing nations with fewer resources to cope with yet another major disease burden. Furthermore, the problem is no longer restricted to the ageing population, as young adults and children are also being diagnosed with T2D. In recent years, there has been a surge in the number of genetic studies of T2D in attempts to identify some of the underlying risk factors. In this review, I highlight the main genes known to cause uncommon monogenic forms of diabetes (e.g. maturity‐onset diabetes of the young—MODY—and insulin resistance syndromes), as well as describe some of the main approaches used to identify genes involved in the more common forms of T2D that result from the interaction between environmental risk factors and predisposing genotypes. Linkage and candidate gene studies have been highly successful in the identification of genes that cause the monogenic variants of diabetes and, although progress in the more common forms of T2D has been slow, a number of genes have now been reproducibly associated with T2D risk in multiple studies. These are discussed, as well as the main implications that the diabetes gene discoveries will have in diabetes treatment and prevention.
Resources, Rights, and Environmental Regulation
Authors: Lee Robert G.
Published: April 2005

Prior to the Human Rights Act 1998, there were significant expectations that it would promote the development of environmental rights and extend remedies for environmental harm. This has not been the case, but then the expectations were probably always false. The paper points to three reasons why: the retention of a strong model of parliamentary sovereignty; the need to mould human rights principles alongside the common law; the traditional reluctance of the courts to determine questions of utility where questions of resource allocation arise. The paper concludes by reflecting on whether one would hope, in any case, to advance the cause of the environment through the mechanism of the Convention and suggests that there may be reasons to doubt the wisdom of this approach.
An Equality and Human Rights Commission Worthy of the Name
Authors: Lester Anthony , Clapinska Lydia
Published: April 2005

The Human Rights Act 1998 came fully into force on 2 October 2000, enabling the European Convention on Human Rights (ECHR) to be relied on directly in our domestic courts.1 The Act lacked provision for a Human Rights Commission to advise and assist alleged victims in bringing proceedings for breaches of Convention rights, to research, intervene in court proceedings, and promote a culture of human rights, although such a Commission had been created for Northern Ireland. A White Paper has now been issued outlining plans for a Commission for Equality and Human Rights. This paper considers the future role and potential impact of the Commission and highlights opportunities that have been missed since October 2000 in its absence. We focus on its human rights aspects and summarize key conditions for the new Commission's success.
Prevalence of obesity in Poland
Authors: Milewicz A. , Jędrzejuk D. , Lwow F. , Białynicka A. S. , Łopatynski J. , Mardarowicz G. , Zahorska‐Markiewicz B.
Published: April 2005

Obesity is an important health problem in Poland affecting adolescents and adults. A study of a Lower Silesian population aged 20–40 years (25 400 participants), between 1993 and 2003, showed an increase in obese women from 8.9% to 15.0%, but no change in men (6.3% vs. 6.5%, respectively). Obesity occurs more frequently in girls and women (6% and 15%) compared to boys and men (4.0% and 6.5%, respectively). Estimation of obesity prevalence in various parts of Poland seems to be regionally dependent; the highest prevalence of obesity was observed in eastern regions of Poland.
Prevalence of obesity in Israel
Authors: Kaluski D. Nitzan , Berry E. M.
Published: April 2005

Israel is a multiethnic society and offers an ongoing ‘experiment’ concerning the cultural determinants of obesity. The First Israeli National Health and Nutrition Survey 1999–2001 (MABAT) measured a representative population of 2782 adults (49% men) aged 25–64 years (mean 43 years); it showed a prevalence of overweight in 39.3% and obesity in 22.9%. Overweight is more common in men and obesity is more prevalent in women; the Israeli Arab population is more obese than the Jewish one.
Obesity: the protein leverage hypothesis
Authors: Simpson S. J. , Raubenheimer D.
Published: April 2005

The obesity epidemic is among the greatest public health challenges facing the modern world. Regarding dietary causes, most emphasis has been on changing patterns of fat and carbohydrate consumption. In contrast, the role of protein has largely been ignored, because (i) it typically comprises only ∼15% of dietary energy, and (ii) protein intake has remained near constant within and across populations throughout the development of the obesity epidemic. We show that, paradoxically, these are precisely the two conditions that potentially provide protein with the leverage both to drive the obesity epidemic through its effects on food intake, and perhaps to assuage it. We formalize this hypothesis in a mathematical model. Some supporting epidemiological, experimental and animal data are presented, and predictions are made for future testing.
Does weight loss prognosis depend on genetic make‐up?
Authors: Moreno‐Aliaga M. J. , Santos J. L. , Marti A. , Martínez J. A.
Published: April 2005

The prevalence of obesity is rising throughout the world. Indeed, obesity has reached epidemic proportions in many developed and transition countries. Obesity is a complex disease with multifactorial origin, which in many cases appears as a polygenic condition affected by environmental factors. Treatment or prevention of obesity is necessary to reverse or avoid the onset of type 2 diabetes and other obesity‐related diseases. Weight loss is a complex trait that depends on many environmental, behavioural and genetic influences. An effective programme for the management of overweight and obesity must take into account all of these factors. Individual responses to weight loss interventions vary widely and reliable predictors of successful slimming are poorly understood. The individual genetic make‐up participating in energy expenditure regulation, appetite control, lipid metabolism and adipogenesis, have been reported to affect the risk of treatment failure in some subjects. In addition, the genotype could also help to predict the changes in lipid profile, cardiovascular risk factors and insulin sensitivity in response to weight loss. Herein, the current evidence from human studies that support the existence of a genetic component and the participation of different polymorphisms in the prognosis of weight loss induced by interventions leading to a negative energy balance are reviewed.
Numerical study of the electrostatic field gradients present in various planar emitter field emission configurations relevant to experimental research
Authors: González-Berríos Adolfo , Piazza Fabrice , Morell Gerardo
Published: April 2005

The generally assumed validity of the V∕dCA approximation for the cathode surface electric field under commonly employed electron field emission configurations was studied. Using appropriate typical dimensions for each configuration, the magnitude of the electric field over the cathode area under the probe was obtained, and especially near critical (i.e., sharp) regions that could lead to residual gas ionization, dielectric breakdown and emission of electrons from unintended areas. The results indicate that the V∕dCA approximation is far from being universally applicable to all the field emission measuring configurations. In particular, the cylindrical probe anode with flat tip gives the most uniform ES, which nearly equals V∕dCA over most of the cathode area under the probe. Spherical and hemispherical probes, on the other hand, result in ES close to V∕dCA only locally near the center, and much lower anywhere around the center. Moreover, the parallel-plate configurations lead to significantly detrimental field enhancement effects near the edges that discourage their use. These results have important implications in the correct evaluation of cold cathode materials for applications requiring large emitting areas or large current densities.
Reduction of the work function on Mo(100) surface covered with ZrO2
Authors: Nakane Hideaki , Satoh Shinya , Adachi Hiroshi
Published: April 2005

The work function of a metal for electron source is one of the measures for evaluating the ability of electron emission, but the values are different depending on the crystal surfaces. In case of molybdenum, the Mo(100) surface has a relatively high value of 4.3eV, however it can be reduced to 2.1eV by heating with a slight layer of zirconium oxide. It is observed that field emission electrons are dominantly extracted from a (100) surface of a molybdenum sharp needle emitter, when the surface is modified with a zirconium oxide. The work function of the surface is estimated from Fowler–Nordheim plots. The estimated average value is 2.1eV, which is remarkably small compared with a commonly accepted value of work function for a ZrO∕W(100) thermal field emitter, namely 2.7–2.9eV, while the smallest reported value is 2.4eV. It is expected that smaller values of work function are desirable for cathode materials to get fine focused electron beams, because less chromatic aberration can be realized. It should be noticed from practical view points that the reduced work function is reproduced easily by applying several times of flash heating after being exposed to air.
Smith–Purcell radiation using a single-tip field emitter
Authors: Neo Yoichiro , Suzuki Yosuke , Sagae Katsumi , Shimawaki Hidetaka , Mimura Hidenori
Published: April 2005

We have successfully observed Smith–Purcell radiation (SPR) using a single-tip n-type Si field emitter in the visible wavelength from 400to700nm at low input power level with beam currents of 20–200nA and accelerating voltages of 25–30kV. Several peaks corresponding to the third and fourth harmonics of SPR are obtained using a 550nm period metal grating and redshifted with decrease of the acceleration voltage. The measured peaks are well explained by the SPR theory.
Scanning anode field emission microscopy analysis for studies of planar cathodes
Authors: Semet V. , Mouton R. , Binh Vu Thien
Published: April 2005

In a scanning anode field emission microscope the field emission current is extracted by a small spherical anode brought, at micrometric proximity, in front of a planar cathode surface. Therefore, the field over the emission area is not uniform and direct quantitative interpretation from the total field emission current versus applied voltage is misleading. The potential distribution of the system composed of a sphere in front of a plane have been calculated to determine the field distribution over the surface in order to define the active field emitting zone and to extract the current density versus the local applied field from the measured total field emission current versus applied voltage characteristics.
Reduction of plasma-induced damage in SiO2 films during pulse-time-modulated plasma irradiation
Authors: Ishikawa Yasushi , Okigawa Mitsuru , Samukawa Seiji , Yamasaki Satoshi
Published: April 2005

Use of a pulse-time-modulated (TM) plasma is an effective way to reduce vacuum ultra-violet (VUV) radiation damage in SiO2 films because such a plasma can reduce the quantity of high-energy electrons while maintaining the electron density during the off time of the TM plasma. To understand the effects of VUV radiation, we measured the VUV-induced current in SiO2 films using a simple on-wafer monitoring technique. We found that the plasma-induced-current in the SiO2 films strongly depended on the VUV photon energy. Under the same conditions, the density of E′ centers in SiO2 films also depended on the photon energy. That is, the plasma-induced currents in the SiO2 films detected by on-wafer monitoring corresponded to the density of E′ centers (dangling bonds) in the films. By using a TM plasma, the plasma-induced current and the E′ center density in SiO2 films can be reduced during the plasma-off time. Consequently, use of a TM plasma can eliminate VUV radiation damage. These results also confirm that our developed on-wafer monitor can predict plasma-induced damage.