bluuebunny/crossref_metadata_2025_split huggingface dataset:
Confronting different models of community structure to species‐abundance data: a Bayesian model comparison
Authors: Etienne Rampal S. , Olff Han 
Published: April 2005

AbstractSpecies 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

AbstractAlthough 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

AbstractHuman 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

AbstractAims  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

AbstractAims  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

AbstractAims  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

AbstractAims  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

AbstractAim  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

AbstractType 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.
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

SummaryObesity 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

SummaryIsrael 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

SummaryThe 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

SummaryThe 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.
Use of Thioredoxin as a Reporter To Identify a Subset of
Escherichia coli
Signal Sequences That Promote Signal Recognition Particle-Dependent Translocation
Authors: Huber Damon , Boyd Dana , Xia Yu , Olma Michael H. , Gerstein Mark , Beckwith Jon 
Published: April 2005

ABSTRACT

We have previously reported that the DsbA signal sequence promotes efficient, cotranslational translocation of the cytoplasmic protein thioredoxin-1 via the bacterial signal recognition particle (SRP) pathway. However, two commonly used signal sequences, those of PhoA and MalE, which promote export by a posttranslational mechanism, do not export thioredoxin. We proposed that this difference in efficiency of export was due to the rapid folding of thioredoxin in the cytoplasm; cotranslational export by the DsbA signal sequence avoids the problem of cytoplasmic folding (C. F. Schierle, M. Berkmen, D. Huber, C. Kumamoto, D. Boyd, and J. Beckwith, J. Bacteriol.
185
:
5706-5713, 2003). Here, we use thioredoxin as a reporter to distinguish SRP-dependent from non-SRP-dependent cleavable signal sequences. We screened signal sequences exhibiting a range of hydrophobicity values based on a method that estimates hydrophobicity. Successive iterations of screening and refining the method defined a threshold hydrophobicity required for SRP recognition. While all of the SRP-dependent signal sequences identified were above this threshold, there were also a few signal sequences above the threshold that did not utilize the SRP pathway. These results suggest that a simple measure of the hydrophobicity of a signal sequence is an important but not a sufficient indicator for SRP recognition. In addition, by fusing a number of both classes of signal sequences to DsbA, we found that DsbA utilizes an SRP-dependent signal sequence to achieve efficient export to the periplasm. Our results suggest that those proteins found to be exported by SRP-dependent signal sequences may require this mode of export because of their tendency to fold rapidly in the cytoplasm.
A Glimpse into the Expanded Genome Content of
Vibrio cholerae
through Identification of Genes Present in Environmental Strains
Authors: Purdy Alexandra , Rohwer Forest , Edwards Rob , Azam Farooq , Bartlett Douglas H. 
Published: April 2005

ABSTRACT

Vibrio cholerae
has multiple survival strategies which are reflected both in its broad distribution in many aquatic environments and its high genotypic diversity. To obtain additional information regarding the content of the
V. cholerae
genome, suppression subtractive hybridization (SSH) was used to prepare libraries of DNA sequences from two southern California coastal isolates which are divergent or absent in the clinical strain
V. cholerae
O1 El Tor N16961. More than 1,400 subtracted clones were sequenced. This revealed the presence of novel sequences encoding functions related to cell surface structures, transport, metabolism, signal transduction, luminescence, mobile elements, stress resistance, and virulence. Flanking sequence information was determined for loci of interest, and the distribution of these sequences was assessed for a collection of
V. cholerae
strains obtained from southern California and Mexican environments. This led to the surprising observation that sequences related to the toxin genes
toxA
,
cnf1
, and
exoY
are widespread and more common in these strains than those of the cholera toxin genes which are a hallmark of the pandemic strains of
V. cholerae
. Gene transfer among these strains could be facilitated by a 4.9-kbp plasmid discovered in one isolate, which possesses similarity to plasmids from other environmental vibrios. By investigating some of the nucleotide sequence basis for
V. cholerae
genotypic diversity, DNA fragments have been uncovered which could promote survival in coastal environments. Furthermore, a set of genes has been described which could be involved in as yet undiscovered interactions between
V. cholerae
and eukaryotic organisms.