bluuebunny/crossref_metadata_2025 huggingface dataset:
Availability and use of public information and conspecific density for settlement decisions in the collared flycatcher
Authors: Doligez Blandine , Pärt Tomas , Danchin Etienne , Clobert Jean , Gustafsson Lars
Published: December 2004

Public information, i.e. local reproductive performance of conspecifics, is expected to be a highly valuable cue for breeding habitat selection. However, the access to this cue may be spatially and temporally constrained. When public information is unavailable, individuals may use other integrative cues, such as the local density of breeders.

Departure decisions of collared flycatchers (Ficedula albicollis) were shown previously to be related to both public information and breeding density, in a long‐term correlative study of a fragmented population. Here, we tested whether flycatchers also use public information (number and condition of fledglings produced locally) and breeding density to make individual settlement decisions in the following year.

Immigration rates were computed to measure the degree of attractiveness of patches to new breeders. We investigated the relative influence of public information and breeding density on immigration rates of yearlings and older adults separately. The access to public information for settlement decisions may indeed be more limited for yearlings.

Immigration rate in a patch increased with mean fledgling number in the previous year for older adults but not for yearlings. Yearling immigration rate was correlated positively to mean fledgling condition when patch breeding density in the previous year was low, but negatively when density was high.

Immigration rates of both yearlings and older adults increased with breeding density in the previous year. Breeding density explained a larger part of the variance in immigration rate than patch reproductive success.

The proportion of yearlings among breeders decreased with increasing patch reproductive success and breeding density in the previous year, suggesting that local competition was high in attractive patches.

Our results thus suggest that public information is also used for immigration decisions. However, decisions of yearlings are more complex than those of older adults, due to their more limited access to public information and the higher impact of intraspecific competition. Conversely, all individuals seemed to cue on breeding density in a similar way. Density is correlated to patch reproductive success, and may be a more easily accessible cue. We discuss the potential advantages of using conspecific density over conspecific reproductive performance for future immigration decisions.
Movements, habitat use and feeding success of cultural clans of South Pacific sperm whales
Authors: Whitehead Hal , Rendell Luke
Published: December 2004

The population of sperm whales (Physeter macrocephalus) in the South Pacific is divided into at least five sympatric vocal clans that almost certainly reflect cultural variation.

We investigated differences in movements and feeding success of groups from different clans off the Galápagos Islands and northern Chile, using data from 87 days spent tracking groups of known clan.

Groups from different clans showed different use of habitat and movement patterns. Off the Galápagos Islands, ‘Plus‐one’ clan groups moved in relatively straight lines while ‘Regular’ clan groups had more convoluted tracks and a more inshore distribution, patterns which were consistent across years.

Groups from different clans had different defecation rates, indicating between‐clan variation in feeding success. Off the Galápagos Islands, ‘Plus‐one’ clan groups were more successful in the depauperate ENSO (‘El Niño/Southern Oscillation’) conditions of 1987. However, in the cooler conditions of 1989, groups of the ‘Regular’ clan had much higher feeding success than those of the ‘Plus‐one’ clan.

Thus we suggest that cultural inheritance in sperm whales incorporates foraging strategy as well as vocal patterns, and that clan membership has fitness consequences.

That clans seem differentially affected by altered climate conditions has implications for the effects of global warming on sperm whales.

The results also support the hypothesis that culturally determined differences in fitness may have affected genetic evolution through the process of cultural hitchhiking.
Patient satisfaction is rated higher by radiation oncology outpatients receiving nutrition intervention compared with usual care
Authors: Isenring E. , Capra S. , Bauer J.
Published: December 2004

Background  Satisfaction with services has been considered vital for the provision of quality health care, however, there are few published papers utilizing patient satisfaction with nutrition services as a measurable outcome.

Method  A randomized, controlled trial investigating the impact of nutrition intervention (NI) vs. usual care (UC) in 54 ambulatory oncology patients receiving radiotherapy to the gastrointestinal or head and neck area demonstrated beneficial impacts in terms of body weight, nutritional status, quality of life and bowel health. This study reports the changes in patient satisfaction that were associated with these improved outcomes for patients receiving NI compared with UC. The patient satisfaction with clinical nutrition services questionnaire was used to measure overall satisfaction and satisfaction with four components of nutrition services 12 weeks after patients commenced radiotherapy.

Results  Patients receiving NI rated satisfaction higher for staff interpersonal skills (P < 0.001), perceived health benefits (P = 0.008), staff presentation skills (P = 0.044) and for overall patient satisfaction with nutrition services (P = 0.002). There were no significant differences between those patients receiving NI or UC for the nutrition supplements factor (P = 0.191).

Conclusions  These data suggest that patients receiving NI perceive nutrition as being beneficial and of higher importance to their health than those receiving UC. This may lead to increased compliance with the nutrition prescription and help explain the better outcomes observed in the NI group compared with the UC group. Patient satisfaction with nutrition services should be conducted regularly to act as a quality‐control measure and target areas for improvement.
A new evidence‐based model for weight management in primary care: the Counterweight Programme
Authors:   The Counterweight Project Team
Published: December 2004

Background/Aims  Obesity has become a global epidemic, and a major preventable cause of morbidity and mortality. Management strategies and treatment protocols are however poorly developed and evaluated. The aim of the Counterweight Programme is to develop an evidence‐based model for the management of obesity in primary care.

Methods  The Counterweight Programme is based on the theoretical model of Evidence‐Based Quality Assessment aimed at improving the management of obese adults (18–75 years) in primary care. The model consists of four phases: (1) practice audit and needs assessment, (2) practice support and training, (3) practice nurse‐led patient intervention, and (4) evaluation. Patient intervention consisted of screening and treatment pathways incorporating evidence‐based approaches, including patient‐centred goal setting, prescribed eating plans, a group programme, physical activity and behavioural approaches, anti‐obesity medication and weight maintenance strategies. Weight Management Advisers who are specialist obesity dietitians facilitated programme implementation. Eighty practices were recruited of which 18 practices were randomized to act as controls and receive deferred intervention 2 years after the initial audit.

Results  By February 2004, 58 of the 62 (93.5%) intervention practices had been trained to run the intervention programme, 47 (75.8%) practices were active in implementing the model and 1256 patients had been recruited (74% female, 26% male, mean age 50.6 years, SD 14). At baseline, 75% of patients had at one or more co‐morbidity, and the mean body mass index (BMI) was 36.9 kg/m2 (SD 5.4). Of the 1256 patients recruited, 91% received one of the core lifestyle interventions in the first 12 months. For all patients followed up at 12 months, 34% achieved a clinical meaningful weight loss of 5% or more. A total of 51% of patients were classed as compliant in that they attended the required level of appointments in 3, 6, and 12 months. For fully compliant patients, weight loss improved with 43% achieving a weight loss of 5% or more at 12 months.

Conclusion  The Counterweight Programme is an evidence‐based weight management model which is feasible to implement in primary care.
Classification of newly‐onset IDDIM and NIDDIM in subjects aged 25–45 years in Sudan
Authors: Elbagir M. N. , Elbagir M. N. , Eltom M. A. , Berne C.
Published: December 2004

Elbagir MN, Eltom MA, Berne C (Departments of Internal Medicine, University Hospital, Uppsala, Sweden and Endocrinology and Diabetes Research Centre, Omdurman Teaching Hospital, Omdurman, Sudan). Classification of newly‐onset IDDIM and NIDDIM in subjects aged 25–45 years in Sudan. J Intern Med 1998; 244: 443–50.

Objectives To investigate the ability of classifying diabetes mellitus with clinical and biochemical characteristics at diagnosis in 25–45 years old patients.

Design We determined age, body mass index (BMI), ICA, fasting C‐peptide and HbA1c at diagnosis, and after 4–27 months follow up, these variables were related to the type of treatment.

Setting Omdurman Teaching Hospital, Sudan.

Subjects Eighty‐six consecutive newly diagnosed diabetic patients, according to WHO criteria, were included.

Results At diagnosis, 27 patients (31.4%) were treated with insulin and 59 (68.6%) with diet and/or oral hypoglycaemic agents (OHA). Insulin‐treated patients at diagnosis were younger, had lower BMI and higher HbA1c. In the non‐insulin treated group at diagnosis, ICA‐negative patients (n = 54) had higher fasting C‐peptide (P < 0.05) than ICA‐positive. The treatment was changed from insulin to diet and/or OHA in 17 patients, and to insulin in six patients. Patients who discontinued insulin had already at diagnosis higher BMI and higher fasting C‐peptide concentration (P < 0.005 and P < 0.05, respectively) than patients remained on insulin. The positive predictive values for insulin treatment of ICA positivity, low fasting C‐ peptide, and low BMI were 90, 78 and 73%, respectively. The sensitivity, specificity and positive predictive values for these variables in concurrence were, respectively, 85, 92 and 69%.

Conclusion The clinical classification of newly‐ diagnosed young Sudanese patients was satisfactory. With regular follow up and early commencement of appropriate treatment, good glycaemic control is certainly attainable. BMI is potentially valuable for the clinical classification in such patients. ICA and fasting serum C‐peptide facilitate the choice of insulin treatment, but cost is a limit to large‐scale use of these tests.
Diabetes: the cost of illness in Sweden
Authors: Henriksson F. , Jönsson B.
Published: December 2004

Henriksson F, Jönsson B (Stockholm School of Economics, Stockholm, Sweden). Diabetes: the cost of illness in Sweden. J Intern Med 1998; 244: 461–8.

Objectives To estimate the total cost of diabetes mellitus in Sweden in 1994 and to compare the cost structure with a former Swedish study and with American studies. The study also aims to investigate how the total cost is distributed between control of and complications of the disease.

Design In order to estimate the economic burden of diabetes mellitus in Sweden in 1994, the cost‐of‐illness method, based on the human capital theory, has been used. Both direct and indirect costs have been estimated using a prevalence approach and a ‘top‐down’ method.

Results The economic burden of diabetes mellitus is estimated at 5746 MSEK (1US$ = 7.50 SEK) in Sweden in 1994. The direct costs are estimated at 2455 MSEK and constitute about 43% of the total cost. The indirect costs (production loss due to morbidity and premature mortality) were the dominant costs and amounted to 3291 MSEK, or 57% of total cost. Comparisons with a previous Swedish study from 1978 show some interesting results. Firstly, the distribution of direct and indirect costs is identical between the two studies. Secondly, the distribution of costs between management/control of the disease and complications was about the same, comparing the situation 16 years apart. Four American studies show a cost structure similar to the cost structure presented in this study.

Conclusions The overall conclusion must be that very little has changed in the cost structure of diabetes in Sweden between 1978 and 1994.
Irritable bowel syndrome: which definitions are consistent?
Authors: Kay L. , Jørgensen T. , Lanng C.
Published: December 2004

Kay L, Jørgensen T, Lanng C (University of Copenhagen and Bispebjerg Hospital, Copenhagen, Denmark). Irritable bowel syndrome: which definitions are consistent?J Intern Med 1998; 244: 489–94.

Objectives Irritable bowel syndrome is inconsistently defined in international literature. Consequently, the resulting differences in study populations may impede any general application of results from one study to another. The aim of this study was to evaluate the consistency of various definitions of irritable bowel syndrome.

Design By means of a questionnaire concerning abdominal symptoms, subjects were categorized as having IBS according to five definitions: (1) two positive Manning criteria; (2) the Rome criteria; (3) a consensus report by Drossman; (4) definition by Talley; and (5) a newly suggested definition by Kay.

Setting The study was carried out as part of a cohort study of 4122 Danes at the Centre of Preventive Medicine (former the Glostrup Population Studies), Glostrup County Hospital, Denmark.

Main outcomes measures Kappa coefficients comparing the irritable bowel populations as defined by the above five definitions.

Results The participation rate was 64.4%. Manning and Rome criteria of irritable bowel syndrome were consistent with a Kappa value of 0.72. A substantial degree of consistency was also present comparing definitions of Drossman, Talley and Kay (kappa, 0.60–0.62). All other comparisons had kappa values below 0.42.

Conclusion Variations in study populations selected by different definitions of irritable bowel syndrome are so large that they impede the general application of any results. There is a need for international agreement on consistent use of one definition of irritable bowel syndrome.
Natural history of myocardial infarction and angina pectoris in a general population sample of middle‐aged men: a 16‐year follow‐up of the Primary Prevention Study, Göteborg, Sweden
Authors: Rosengren A. , Wilhelmsen L. , Hagman M. , Wedel H.
Published: December 2004

Rosengren A, Wilhelmsen L, Hagman M, Wedel H (Östra University Hospital, Göteborg; Kungälv Hospital, Kungälv; and Nordic School of Public Health, Göteborg, Sweden). Natural history of myocardial infarction and angina pectoris in a general population sample of middle‐aged men: a 16‐year follow‐up of the Primary Prevention Study, Göteborg, Sweden. J Intern Med 1998; 244: 495–505.

Objectives Although many studies have described prognosis in patients with coronary heart disease (CHD), few have compared outcome in men with clinical evidence of CHD with healthy men from the general population over an extended follow‐up. This study aimed to compare long‐term prognosis in men with a history of myocardial infarction (MI) and in men with angina pectoris (AP) without MI, with men without clinical signs of CHD.

Design Longitudinal general population study.

Setting City of Göteborg, Sweden.

Subjects From a general population sample, 195 men who had survived an MI for 0–19 years (median 3 years) and 314 men with AP but no MI (uncomplicated AP) at baseline in 1974–77 were identified and compared with 6591 men without clinical coronary disease. All were aged 51–59 years. Incident non‐fatal and fatal cases occurring until the beginning of 1983 were also followed (n= 317).

Main outcome measures Death from CHD, from other causes and from all causes during a follow‐up of at least 16 years.

Results Overall survival was 72% amongst men without coronary disease, 53% amongst men with uncomplicated AP and 34% amongst men with past MI at baseline. In survivors of MI the risk‐factor‐adjusted relative risk (RR) of coronary death during follow‐up was 6.67 (95% confidence interval (CI) 5.29–8.39), of dying from non‐cardiovascular causes 1.35 (0.96–1.91), and of dying from any cause 3.20 (2.67–3.83). During the first 4 years after the baseline examination, the adjusted RR of CHD death was 15.96 (10.29–24.74), and of dying from any cause 5.22 (3.68–7.41). During the last 4 years of follow‐up, relative risk was still 5.87 (3.44–10.01) for CHD death and 2.93 (2.05–4.18) for death from any cause. In men with uncomplicated AP, the adjusted relative risk of CHD death during the first 4 years was 4.05 (2.27–7.22) and 3.23 (2.10–4.96) during the last 4‐year period. After the first year, the incident MI cases had the same average annual mortality (about 5%) as the prevalent cases.

Conclusions In survivors of MI, mortality risk remained high even after an extended follow‐up. Men with angina had a better prognosis, but still a compromised survival compared with the general population.
Primary intestinal T‐cell lymphoma and sclerosing cholangitis: a cytokine‐mediated association?
Authors: Schattner A. , Kozak N. , Lassry Y. , SokolovskAya N.
Published: December 2004

Schattner A, Kozak N, Lassry Y, Sokolovskya N (Kaplan Medical Center, Rehovot, and Hadassah Medical School, Jerusalem, Israel). Primary intestinal T‐cell lymphoma and sclerosing cholangitis: a cytokine‐mediated association? (Case Report). J Intern Med 1998; 244: 537–41.

A 63‐year‐old woman with a 1‐year history of abdominal pain and intrahepatic cholestasis developed anorexia, weight loss, lassitude and diarrhoea. Studies led to a diagnosis of primary intestinal T‐cell lymphoma involving especially the proximal small intestine and infiltrating the mesenteric lymph nodes, bone marrow and skin. An associated severe hypoalbuminaemia (1.3 g dL−1) was most probably the result of protein‐losing enteropathy. Liver biopsy demonstrated concentric fibrosis of the bile ducts ('onion skin' lesions, with an inflammatory cell infiltrate and lymphoid aggregates) and was considered almost pathognomonic of primary sclerosing cholangitis. Sudden death due to pulmonary embolism occurred and a limited autopsy confirmed the diagnosis. Other associated diseases such as coeliac disease or inflammatory bowel disease were not found. This first report of the simultaneous occurrence of two rare diseases – primary sclerosing cholangitis and intestinal T‐cell lymphoma – may indicate an intriguing association, possibly mediated by the effect of cytokines released by the infiltrating T‐cells into the portal circulation.
Accumulation of plasma nucleosomes upon treatment with anti‐tumour necrosis factor‐α antibodies
Authors: D'Auria F. , Rovere‐Querini P. , Giazzon M. , Ajello P. , Baldissera E. , Manfredi A. A. , Sabbadini M. G.
Published: December 2004

Objective.  Patients undergoing anti‐tumour necrosis factor‐α (TNF‐α) treatment often develop autoantibodies. Apoptotic cell antigens are a potential initiating stimulus for autoantibodies. Our goal was to verify whether anti‐cytokine therapy causes the release of nucleosomes, a major autoantigen generated during cell death.

Design.  Laboratory research study with comparison group.

Setting.  Clinical Immunology Unit and Lab, H San Raffaele University Hospital, Italy.

Subjects.  Eleven healthy controls and 87 rheumatic patients were studied, including 51 with rheumatoid arthritis (RA) and 33 patients with systemic lupus erythematosus (SLE).

Interventions.  Vein blood samples were taken via the antecubital vein. Blood was retrieved from 11 patients before and after injection of anti‐TNF‐α humanized antibodies. Nucleosomes were measured with an enzyme‐linked immunosorbent assay. Cell death induced by anti‐TNF‐α antibodies and by the soluble cytokine was assessed in vitro.

Main outcome measures.  Nucleosome level by treatment.

Results.  Enzyme‐linked immunosorbent assay effectively detected nucleosomes either released by dying cells in vitro or circulating in the plasma. SLE but not RA patients had circulating nucleosomes at the steady state. Eight of 11 patients had significantly higher levels of plasma nucleosomes after infliximab. Minute amounts of TNF‐α enabled infliximab to induce cell death in vitro.

Conclusions.  The accumulation of nucleosomes possibly fosters the development of autoantibodies in subjects with appropriate genetic backgrounds.
Extracellular role of HMGB1 in inflammation and sepsis
Authors: Wang H. , Yang H. , Tracey K. J.
Published: December 2004

High mobility group box 1 (HMGB1), a 30 kDa nuclear and cytosolic protein widely studied as a transcription factor and growth factor, has recently been identified as a cytokine mediator of lethal systemic inflammation (e.g. endotoxaemia and sepsis), arthritis and local inflammation. It is released by activated macrophages, and serum levels increase significantly during endotoxaemia, sepsis and arthritis with significant delayed kinetics in comparison with tumour necrosis factor (TNF) and interleukin‐1β. Recently identified biological activities of HMGB1 include activation of macrophages/monocytes to release proinflammatory cytokines, upregulation of endothelial adhesion molecules, stimulation of epithelial cell barrier failure, and mediation of fever and anorexia. Passive immunization with anti‐HMGB1 antibodies confers significant protection against lethal endotoxaemia, sepsis, arthritis and lipopolysaccharide‐induced acute lung injury, even when antibody administration is delayed until after the early TNF responses have resolved. Strategies to inhibit HMGB1 activity and release are being investigated in these and other preclinical models of acute and chronic inflammation.
The current biology of resistin
Authors: Steppan Claire M. , Lazar Mitchell A.
Published: December 2004

Obesity and noninsulin‐dependent diabetes mellitus are globally epidemic. Insulin resistance is a major contributor to the pathogenesis of type II diabetes and plays a role in numerous other metabolic disorders including hypertension, dyslipidaemia and atherosclerosis. Obesity, in particular visceral adiposity, is positively correlated with insulin resistance. Although this correlation between adiposity and insulin resistance is well established in human beings as well as in rodent models, the mechanisms involved in obesity‐related insulin resistance are not fully defined. One mechanism is that factors secreted from adipocytes can affect peripheral insulin resistance. One candidate for such a factor is resistin, an adipocyte‐secreted hormone that impairs glucose homeostasis and insulin action in the mouse. This review will summarize our current understanding of resistin and will attempt to provide a framework for future study of its role in rodent and human physiology.
Statistical issues in interpreting clinical trials
Authors: DeMets D. L.
Published: December 2004

Randomized clinical trial is an important research tool in evaluating new therapeutic agents, devices and procedures. In order to obtain reliable and unbiased results, careful consideration must be given in the design and conduct of the trial. However, bias can be introduced in the analysis of the final data if certain principles are not followed. Several issues are described that make interpretation of analyses challenging. These include the intent‐to‐treat principle, the use of surrogate outcome measures, subgroup analyses, missing data and noninferiority trials.
Rapid Emergency Medicine score: a new prognostic tool for in‐hospital mortality in nonsurgical emergency department patients
Authors: Olsson T. , Terent A. , Lind L.
Published: December 2004

Objectives.  To evaluate the predictive accuracy of the scoring system Rapid Acute Physiology score (RAPS) in nonsurgical patients attending the emergency department (ED) regarding in‐hospital mortality and length of stay in hospital (LOS), and to investigate whether the predictive ability of RAPS could be improved by extending the system.

Design.  Prospective cohort study.

Setting.  An adult ED of a 1200‐bed university hospital.

Subjects.  A total of 12 006 nonsurgical patients presenting to the ED during 12 consecutive months.

Methods.  For all entries to the ED, RAPS (including blood pressure, respiratory rate, pulse rate and Glasgow coma scale) was calculated. The RAPS system was extended by including the peripheral oxygen saturation and patient age (Rapid Emergency Medicine score, REMS) and this new score was calculated for each patient. The statistical associations between the two scoring systems and in‐hospital mortality as well as LOS in hospital were examined.

Results.  The REMS was superior to RAPS in predicting in‐hospital mortality [area under receiver operating characteristic (ROC) curve 0.852 ± 0.014 SEM for REMS compared with 0.652 ± 0.019 for RAPS, P < 0.05]. An increase of 1‐point in the 26‐point REMS scale was associated with an OR of 1.40 for in‐hospital death (95% CI: 1.36–1.45, P < 0.0001). Similar results were obtained in the major patient groups (chest pain, stroke, coma, dyspnoea and diabetes), in all age groups and in both sexes. The association between REMS and LOS was modest (r = 0.47, P = 0.0001).

Conclusions.  The REMS was a powerful predictor of in‐hospital mortality in patients attending the ED over a wide range of common nonsurgical disorders.
Highly elevated serum phyto‐oestrogen concentrations in patients with diabetic nephropathy
Authors: Von Hertzen L. , Forsblom C. , Stumpf K. , Pettersson‐Fernholm K. , Adlercreutz H. , Groop P.‐H. ,   on behalf of the FinnDiane Study Group
Published: December 2004

Background and objectives.  Phyto‐oestrogens, naturally occurring phenolic, hormone‐like compounds, have raised considerable interest due to their anticarcinogenic, antiatherogenic and antioxidative potential. Oxidative stress may be one of the key factors in the development of vascular complications in patients with type 1 diabetes. Here, we tested the hypothesis that high concentrations of phyto‐oestrogens in serum may be associated with lower occurrence of vascular complications in these patients.

Subjects.  A total of 400 patients, recruited consecutively from the participant register of the nationwide FinnDiane study of type 1 diabetes and divided into four parallel groups according to the severity of their renal disease with 100 patients to each group: (i) normoalbuminuric patients, (ii) microalbuminuric patients, (iii) macroalbuminuric patients, and (iv) patients with end‐stage renal disease (ESRD).

Main outcome  measures.  Phyto‐oestrogen concentrations in serum (enterolactone, daidzein, genistein and equol) and urine (enterolactone), assessed by time‐resolved fluoroimmunoassay.

Results.  Highly elevated serum concentrations of phyto‐oestrogens were measured amongst patients with diabetic nephropathy, and low concentrations amongst patients without diabetic complications. The pattern was similar for all phyto‐oestrogens measured, although the increase in mean serum concentrations along with the increasing severity of renal disease was steepest for enterolactone, ranging from 13 nmol L−1 amongst women and 18 nmol L−1 amongst men in normoalbuminuric patients to 181 and 206 nmol L−1 in women and men, respectively, in patients with ESRD (P < 0.001 for both genders between the groups). A strong correlation between serum enterolactone and creatinine concentration was found (r = 0.60, P < 0.001).

Conclusions.  The serum concentration of phyto‐oestrogens and the severity of diabetic renal disease showed a close positive association, suggesting that phyto‐oestrogens are unable to provide any major protective effect, through antioxidative or other mechanisms, on the development of diabetic renal and cardiovascular complications.
Metapopulation models for historical inference
Authors: Wakeley John
Published: December 2004

The genealogical process for a sample from a metapopulation, in which local populations are connected by migration and can undergo extinction and subsequent recolonization, is shown to have a relatively simple structure in the limit as the number of populations in the metapopulation approaches infinity. The result, which is an approximation to the ancestral behaviour of samples from a metapopulation with a large number of populations, is the same as that previously described for other metapopulation models, namely that the genealogical process is closely related to Kingman's unstructured coalescent. The present work considers a more general class of models that includes two kinds of extinction and recolonization, and the possibility that gamete production precedes extinction. In addition, following other recent work, this result for a metapopulation divided into many populations is shown to hold both for finite population sizes and in the usual diffusion limit, which assumes that population sizes are large. Examples illustrate when the usual diffusion limit is appropriate and when it is not. Some shortcomings and extensions of the model are considered, and the relevance of such models to understanding human history is discussed.
Using genetic markers to estimate the pollen dispersal curve
Authors: Austerlitz Frederic , Dick Christopher W. , Dutech Cyril , Klein Etienne K. , Oddou‐Muratorio Sylvie , Smouse Peter E. , Sork Victoria L.
Published: December 2004

Pollen dispersal is a critical process that shapes genetic diversity in natural populations of plants. Estimating the pollen dispersal curve can provide insight into the evolutionary dynamics of populations and is essential background for making predictions about changes induced by perturbations. Specifically, we would like to know whether the dispersal curve is exponential, thin‐tailed (decreasing faster than exponential), or fat‐tailed (decreasing slower than the exponential). In the latter case, rare events of long‐distance dispersal will be much more likely. Here we generalize the previously developed twogener method, assuming that the pollen dispersal curve belongs to particular one‐ or two‐parameter families of dispersal curves and estimating simultaneously the parameters of the dispersal curve and the effective density of reproducing individuals in the population. We tested this method on simulated data, using an exponential power distribution, under thin‐tailed, exponential and fat‐tailed conditions. We find that even if our estimates show some bias and large mean squared error (MSE), we are able to estimate correctly the general trend of the curve — thin‐tailed or fat‐tailed — and the effective density. Moreover, the mean distance of dispersal can be correctly estimated with low bias and MSE, even if another family of dispersal curve is used for the estimation. Finally, we consider three case studies based on forest tree species. We find that dispersal is fat‐tailed in all cases, and that the effective density estimated by our model is below the measured density in two of the cases. This latter result may reflect the difficulty of estimating two parameters, or it may be a biological consequence of variance in reproductive success of males in the population. Both the simulated and empirical findings demonstrate the strong potential of twogener for evaluating the shape of the dispersal curve and the effective density of the population (de).
Identifying adaptive genetic divergence among populations from genome scans
Authors: Beaumont Mark A. , Balding David J.
Published: December 2004

The identification of signatures of natural selection in genomic surveys has become an area of intense research, stimulated by the increasing ease with which genetic markers can be typed. Loci identified as subject to selection may be functionally important, and hence (weak) candidates for involvement in disease causation. They can also be useful in determining the adaptive differentiation of populations, and exploring hypotheses about speciation. Adaptive differentiation has traditionally been identified from differences in allele frequencies among different populations, summarised by an estimate of FST. Low outliers relative to an appropriate neutral population‐genetics model indicate loci subject to balancing selection, whereas high outliers suggest adaptive (directional) selection. However, the problem of identifying statistically significant departures from neutrality is complicated by confounding effects on the distribution of FST estimates, and current methods have not yet been tested in large‐scale simulation experiments. Here, we simulate data from a structured population at many unlinked, diallelic loci that are predominantly neutral but with some loci subject to adaptive or balancing selection. We develop a hierarchical‐Bayesian method, implemented via Markov chain Monte Carlo (MCMC), and assess its performance in distinguishing the loci simulated under selection from the neutral loci. We also compare this performance with that of a frequentist method, based on moment‐based estimates of FST. We find that both methods can identify loci subject to adaptive selection when the selection coefficient is at least five times the migration rate. Neither method could reliably distinguish loci under balancing selection in our simulations, even when the selection coefficient is twenty times the migration rate.
Hidden biodiversity of the extremophilic Cyanidiales red algae
Authors: CINIGLIA CLAUDIA , YOON HWAN SU , POLLIO ANTONINO , PINTO GABRIELE , BHATTACHARYA DEBASHISH
Published: December 2004

The Cyanidiales is a group of asexual, unicellular red algae, which thrive in acidic and high temperature conditions around hot springs. These unicellular taxa have a relatively simple morphology and are currently classified into three genera, Cyanidium, Cyanidioschyzon and Galdieria. Little is known, however, about the biodiversity of Cyanidiales, their population structure and their phylogenetic relationships. Here we used a taxonomically broadly sampled three‐gene data set of plastid sequences to infer a robust phylogenetic framework for the Cyanidiales. The phylogenetic analyses support the existence of at least four distinct Cyanidiales lineages: the Galdieria spp. lineage (excluding Galdieria maxima), the Cyanidium caldarium lineage, a novel monophyletic lineage of mesophilic Cyanidium spp. and the Cyanidioschyzon merolae plus Galdieria maxima lineage. Our analyses do not support the notion of a mesophilic ancestry of the Cyanidiales and suggest that these algae were ancestrally thermo‐acidotolerant. We also used environmental polymerase chain reaction (PCR) for the rbcL gene to sample Cyanidiales biodiversity at five ecologically distinct sites at Pisciarelli in the Phlegrean Fields in Italy. This analysis showed a high level of sequence divergence among Cyanidiales species and the partitioning of taxa based on environmental conditions. Our research revealed an unexpected level of genetic diversity among Cyanidiales that revises current thinking about the phylogeny and biodiversity of this group. We predict that future environmental PCR studies will significantly augment known biodiversity that we have discovered and demonstrate the Cyanidiales to be a species‐rich branch of red algal evolution.
Effects of variation at the flower‐colour A locus on mating system parameters in Ipomoea purpurea
Authors: Fehr Carla , Rausher Mark D.
Published: December 2004

Although alleles at both the W and A loci in the common morning glory, Ipomoea purpurea, produce similar white‐flowered phenotypes, these alleles differ by over an order of magnitude in average frequency. In this initial attempt to determine the causes of this difference, we employed artificial arrays of plants to estimate mating system characteristics (total siring success, selfing rates and contribution to the outcross pollen pool) for the homozygous pigmented and white‐flowered genotypes at the A locus. This experiment demonstrates that: (1) at both low and high frequencies, white‐flowered plants were visited by pollinators at the same rate as plants with pigmented flowers; (2) at both frequencies, the a allele exhibited a greater total siring success (self and outcross pollen) than the A allele; (3) individuals of both genotypes contributed equally to the outcross pollen pool; and (4) aa plants may have a higher selfing rate than AA plants. Coupled with minimal inbreeding depression in I. purpurea, these observations indicate that the allele producing white flowers enjoys a transmission advantage that would tend to cause this allele to increase in frequency. This transmission advantage is very similar to that shown previously to be operating on the white‐flowered allele at the W locus, although the specific causes of the advantage appear to differ between loci. The frequency difference between the two alleles is thus not likely to be due to differences in the effect of flower‐colour variation on transmission. Rather, substantially greater deleterious pleiotropic effects associated with the white‐flower a allele is likely to be the primary cause of the frequency difference.
Assessment of prey overlap between a native (Polistes humilis) and an introduced (Vespula germanica) social wasp using morphology and phylogenetic analyses of 16S rDNA
Authors: Kasper Marta L. , Reeson Andrew F. , Cooper Steven J. B. , Perry Kym D. , Austin Andrew D.
Published: December 2004

In newly invaded communities, interspecific competition is thought to play an important role in determining the success of the invader and its impact on the native community. In southern Australia, the native Polistes humilis was the predominant social wasp prior to the arrival of the exotic Vespula germanica (Hymenoptera: Vespidae). Both species forage for similar resources (water, pulp, carbohydrate and protein prey), and concerns have arisen about potential competition between them. The aim of this study was to identify the protein foods that these wasps feed on. As many prey items are masticated by these wasps to the degree that they cannot be identified using conventional means, morphological identification was complemented by sequencing fragments of the mitochondrial 16S rRNA gene. GenBank searches using blast and phylogenetic analyses were used to identify prey items to at least order level. The results were used to construct complete prey inventories for the two species. These indicate that while P. humilis is restricted to feeding on lepidopteran larvae, V. germanica collects a variety of prey of invertebrate and vertebrate origin. Calculated values of prey overlap between the two species are used to discuss the implications of V. germanica impacting on P. humilis. Results obtained are compared to those gained by solely ‘conventional’ methods, and the advantages of using DNA‐based taxonomy in ecological studies are emphasized.
Phylogeography of olive ridley turtles (Lepidochelys olivacea) on the east coast of India: implications for conservation theory
Authors: Shanker K. , Ramadevi J. , Choudhury B. C. , Singh L. , Aggarwal R. K.
Published: December 2004

Orissa, on the east coast of India, is one of the three mass nesting sites in the world for olive ridley turtles (Lepidochelys olivacea). This population is currently under threat as a result of fishery‐related mortality; more than 100 000 olive ridleys have been counted dead in the last 10 years in Orissa. In general, the globally distributed olive ridley turtle has received significantly less conservation attention than its congener, the Kemp's ridley turtle (L. kempi), because the latter is recognized as a distinct species consisting of a single endangered population. Our study of mitochondrial DNA haplotypes suggests that the ridley population on the east coast of India is panmictic, but distinct from all other populations including Sri Lanka. About 96% of the Indian population consisted of a distinct ‘K’ clade with haplotypes not found in any other population. Nested clade analysis and conventional analysis both supported range expansions and/or long‐distance colonization from the Indian Ocean clades to other oceanic basins, which suggested that these are the ancestral source for contemporary global populations of olive ridley turtles. These data support the distinctiveness of the Indian Ocean ridleys, suggesting that conservation prioritization should be based on appropriate data and not solely on species designations.
North Atlantic phylogeography and large‐scale population differentiation of the seagrass Zostera marina L.
Authors: OLSEN JEANINE L. , STAM WYTZE T. , COYER JAMES A. , REUSCH THORSTEN B. H. , BILLINGHAM MARTIN , BOSTRÖM CHRISTOFFER , CALVERT ELIZABETH , CHRISTIE HARTVIG , GRANGER STEPHEN , LUMIÈRE RICHARD LA , MILCHAKOVA NATALIYA , OUDOT‐LE SECQ MARIE‐PIERRE , PROCACCINI GABRIELE , SANJABI BAHRAM , SERRÃO ESTER , VELDSINK JAN , WIDDICOMBE STEPHEN , WYLLIE‐ECHEVERRIA SANDY
Published: December 2004

As the most widespread seagrass in temperate waters of the Northern Hemisphere, Zostera marina provides a unique opportunity to investigate the extent to which the historical legacy of the last glacial maximum (LGM18 000–10 000 years bp) is detectable in modern population genetic structure. We used sequences from the nuclear rDNA–internal transcribed spacer (ITS) and chloroplast matK‐intron, and nine microsatellite loci to survey 49 populations (> 2000 individuals) from throughout the species’ range. Minimal sequence variation between Pacific and Atlantic populations combined with biogeographical groupings derived from the microsatellite data, suggest that the trans‐Arctic connection is currently open. The east Pacific and west Atlantic are more connected than either is to the east Atlantic. Allelic richness was almost two‐fold higher in the Pacific. Populations from putative Atlantic refugia now represent the southern edges of the distribution and are not genetically diverse. Unexpectedly, the highest allelic diversity was observed in the North Sea–Wadden Sea–southwest Baltic region. Except for the Mediterranean and Black Seas, significant isolation‐by‐distance was found from ~150 to 5000 km. A transition from weak to strong isolation‐by‐distance occurred at ~150 km among northern European populations suggesting this scale as the natural limit for dispersal within the metapopulation. Links between historical and contemporary processes are discussed in terms of the projected effects of climate change on coastal marine plants. The identification of a high genetic diversity hotspot in Northern Europe provides a basis for restoration decisions.
Specialization and habitat: spatial and environmental effects on abundance and genetic diversity of forest generalist and specialist Carabus species
Authors: BROUAT C. , CHEVALLIER H. , MEUSNIER S. , NOBLECOURT T. , RASPLUS J.‐Y.
Published: December 2004

Habitat specialist species are supposed to be more susceptible to variations in local environmental characteristics than generalists. To test this hypothesis, we conducted a comparative analysis on abundance and genetic diversity of forest carabids differing in their habitat requirements. Four species were sampled in forests characterized by abiotic, landscape and biotic environmental variables. A statistical framework based on canonical correspondence analysis was used for one habitat generalist and one habitat specialist species to determine the relative contribution of environmental variables in structuring inter‐ and intrapopulational genetic diversity depicted by microsatellites. Our results showed that sympatric species differed in their sensitivity to environmental variables. The same variables were found to be important in analyses of abundance and genetic data. However, specialization was not related to a greater sensitivity to local environmental characteristics. The strong impact of spatial variables on genetic data suggested that genetic variation among populations would largely reflect the response of individual species to dispersal opportunities more than the effect of habitat quality.
Multiple paternity in an aggregate breeding amphibian: the effect of reproductive skew on estimates of male reproductive success
Authors: MYERS E. M. , ZAMUDIO K. R.
Published: December 2004

Aggregate, or explosive, breeding is widespread among vertebrates and likely increases the probability of multiple paternity. We assessed paternity in seven field‐collected clutches of the explosively breeding spotted salamander (Ambystoma maculatum) using 10 microsatellite loci to determine the frequency of multiple paternity and the number of males contributing to a female's clutch. Using the Minimum Method of allele counts, multiple paternity was evident in 70% of these egg masses. Simple allele counts underestimate the number of contributing males because this method cannot distinguish multiple fathers with common or similar alleles. Therefore, we used computer simulations to estimate from the offspring genotypes the most likely number of contributing fathers given the distributions of allele frequencies in this population. We determined that two to eight males may contribute to A. maculatum clutches; therefore, multiple paternity is a common strategy in this aggregate breeding species. In aggregate mating systems competition for mates can be intense, thus differential reproductive success (reproductive skew) among males contributing to a female's clutch could be a probable outcome. We use our data to evaluate the potential effect of reproductive skew on estimates of the number of contributing males. We simulated varying scenarios of differential male reproductive success, ranging from equal contribution to high reproductive skew among contributing sires in multiply sired clutches. Our data suggest that even intermediate levels of reproductive skew decrease confidence substantially in estimates of the number of contributing sires when parental genotypes are unknown.
A simple method for the calculation of microsatellite genotype distances irrespective of ploidy level
Authors: BRUVO RUŽICA , MICHIELS NICOLAAS K. , D’SOUZA THOMAS G. , SCHULENBURG HINRICH
Published: December 2004

Microsatellites are powerful molecular markers, used commonly to estimate intraspecific genetic distances. With the exception of band sharing similarity index, available distance measures were developed specifically for diploid organisms and are unsuited for comparisons of polyploids. Here, we present a simple method for calculation of microsatellite genotype distances, which takes into account mutation processes and permits comparison of individuals with different ploidy levels. This method should provide a valuable tool for intraspecific analyses of polyploid organisms, which are widespread among plants and some animal taxa. An illustration is given using data from the planarian flatworm Schmidtea polychroa (Platyhelminthes).