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1.
Background: Several studies have reported associations between season of birth and reproductive characteristics such as menarcheal age, fecundability, and twinning, but the results are inconsistent with respect to the location of high- and low-risk seasons. To assess whether this disagreement could be due to the use of populations from different geographic areas and time frames instead of different etiologic pathways, we investigated the season-of-birth dependency of a variety of reproductive outcomes within one time- and arealimited population. Methods: In a historic follow-up study, the reconstituted families of 800 women born between 1873 and 1887 in or near Rotterdam, The Netherlands, were used to determine eight types of reproductive outcome: childlessness, interval to first pregnancy, pregnancy interval, stillbirth, neonatal death, postneonatal death, multiple birth, and gender of offspring. The relation of these outcomes with season of birth was modeled using cosinor functions with periods of 1 year or a half year. Data were analyzed by use of logistic regression or general estimation equations (GEE), dependent on whether outcomes could occur more than once per woman. Results: Peaks in the model-based risks of reproductive failure were found within two small temporal ranges, January 1 to February 11 and July 1 to August 11 for all outcomes except gender. The picture did not change after controlling for known and possible risk factors, including age, offspring's birth cohort, and some social variables. Conclusions: This study reconfirms the idea that seasonal factors around conception or birth influence later reproductive characteristics. Observing the consistency of the location of high-risk seasons across a variety of outcomes, the explanation of season-of-birth dependency of different reproductive outcomes need not involve multiple etiological pathways. (Chronobiology International, 18(3), 525-539, 2001)  相似文献   

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Objective: This study was undertaken to provide an analysis of the actual oral heath care for frail elderly people living in different settings and to explore opinions of dentists towards new concepts in developing a community approach. Method: Data were collected from a sample of 101 dentists (15%) in the county of Antwerp using a self‐administered 30‐item questionnaire including questions about age, gender, education, organisational aspects of dental surgery, questions concerning dentists’ own contribution to oral healthcare services for frail elderly people and statements concerning opinions and attitude toward the organisation of oral health care for frail elderly people. At the same time, qualitative data were collected from focus group sessions with all participating dentists. Non‐parametric analysis was used to explore possible relationships between opinion and possible explanatory variables. Results: Half of the dentists offered dental services to residential or nursing homes (mean number of treatments a year: 5.4) and at home (mean number of treatments a year: 2.4). Prosthetic treatments such as relieving denture pressure points, repairing, rebasing and making new dentures were carried out in 77.4% and 76.7% of the cases in residential or nursing homes and at home respectively. Extractions were carried out in 16% and 18.6% of the cases in both living situations respectively. The main reasons for dentists refusing domiciliary oral health care were the absence of dental equipment (63%), lack of time (19%), with 11% convincing the patients to be treated in their dental surgery. Analysis showed different opinions of dentists depending on age, gender and university of education; however, statistically significant differences were only found by age. Conclusion: The older the dentist, the greater the tendency to refuse domiciliary oral healthcare services. The younger dentists were reluctant to cooperate in the provision of oral health care in a structured community approach.  相似文献   

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A challenging activity in the promotion of sustainable development is to synthesise indicators that can support decision-making. In developing countries such as Brazil, the use of information in support of the health and health-related environment of humans needs improvement. This paper presents a proposal for a system that can evaluate human health and urban environment sanitation in an integrated manner. The indicators selected for human health were child mortality rate, mortality rate due to acute diarrhoea for all ages and 1–4-year-old mortality rate due to acute respiratory tract infections. Environmental sanitation has been represented by indicators of sanitation coverage, such as sewerage. The paper describes the design of a fuzzy linguistic model that synthesises these indicators. The designed fuzzy rule-based system has proved to be a useful tool to integrate information and assist in the public planning of interrelated areas.  相似文献   

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Recent literature shows that ethics of care can be used as a theoretical basis to add a new, important dimension to social issues. This paper argues for a similar extension of the theoretical support from ethics of care to an area in bioethics. Specifically, it contends that a justification based ethics of care can be constructed to argue for a moral obligation to give some priority in the HIV-related initiatives to one of most vulnerable groups; namely, the rural women in India. In an epidemic situation this care-based approach has certain advantages as a moral justification over the usual traditional approaches.  相似文献   

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A multidisciplinary panel debated the role of screening mammography in fighting breast cancer during the Health and Medicine for Women continuing medical education (CME) conference at Yale Medical School in September 2010. Different guidelines from professional societies have presented conflicting recommendations for patients regarding both the benefits of mammography and the appropriate age and frequency of screening. In addition, a recent longitudinal study argues that screening mammography may only offer a modest benefit in terms of reducing cancer mortality. In light of these considerations, the panel debated whether mammography should be an informed decision that must be discussed and individualized for each patient based on the context of risk factors such as family history, age, and genetic dispositions.  相似文献   

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Early detection is imperative for improving survival from ovarian cancer, the leading cause of death from gynecological cancer in the United States. At the Health and Medicine for Women continuing medical education (CME) conference at Yale in September 2010, Dr. Gil Mor, a researcher in the Department of OB/GYN at Yale, presented recent advances on the pathophysiology of ovarian cancer. These advances, and particularly our growing understanding of cancer stem cells, may help overcome the limitations of current ovarian cancer detection and treatment methods.  相似文献   

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In several fish species with paternal care, females prefer malesguarding many eggs in their nest. This preference might be advantageousbecause the presence of many other eggs dilutes the risk ofnewly laid eggs being eaten by the father. To evaluate thishypothesis quantitatively, we constructed a simulation modelthat mimics the breeding biology of the blenny Aidablenniussphynx. In contrast to earlier verbal models, the costs of choiceare explicitly taken into account We systematically varied factorssuch as the stringency of choosiness and the level and natureof the costs of choice. For realistic parameter values femalechoosiness may result in a fitness advantage of more than 50%.The optimal choice strategy created a distribution of eggs overthe nests which resembles that found in the field for A. sphynx.Our model shows that the relative fitness of a choice strategyis not constant but frequency dependent in a complicated way.If most females are choosy, a bimodal distribution of eggs overthe nests results, with many nests containing few and some nestscontaining many eggs. In such a situation choosiness is profitable,since randomly laying females will often lay their eggs in nestswith few eggs, producing a high mortality per egg due to filialcannibalism. If, on the other hand, only few choosers are present,their influence on the egg distribution is limited. A unimodaldistribution results which is profitable for nonchoosers, sincethe average egg mortality is low and nonchoosers do not bearthe costs of choice. The positive relation between chooser frequencyand chooser fitness makes it easy to understand why choosinessis evolutionarily stable. However, it is not obvious how thetrait is established by selection in the first place.[BehavEcol 7: 353–361 (1996)  相似文献   

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An estimated 40 million women of childbearing age suffer from schistosomiasis. Animal models indicate a deleterious effect of maternal schistosomiasis on pregnancy outcomes. To date there is a lack of epidemiological evidence evaluating schistosomiasis-related morbidity in pregnancy. This study was designed to describe the impact of urogenital schistosomiasis on pregnancy outcomes in a highly endemic region of central Africa. Pregnant women attending antenatal clinics in Fougamou and Lambaréné, Gabon, were consecutively screened for the presence of Schistosoma haematobium eggs in diurnal urine samples. Maternal and newborn characteristics assessed at delivery were compared between infected and uninfected mothers. The impact of maternal schistosomiasis on low birth weight and preterm delivery was assessed using logistic regression analysis. Urogenital schistosomiasis was diagnosed in 103 (9%) of 1115 pregnant women. Maternal age was inversely associated with the prevalence of urogenital schistosomiasis, with a higher burden amongst nulliparous women. Low birth weight was more common amongst infants of S. haematobium-infected mothers. This association was unaffected by controlling for demographic characteristics, gestational age and Plasmodium infection status (adjusted Odds Ratio 1.93; 95% confidence interval: 1.08–3.42). Other risk factors associated with low birth weight delivery were underweight mothers (adjusted Odds Ratio 2.34; 95% confidence interval: 1.12–4.92), peripheral or placental Plasmodium falciparum infection (adjusted Odds Ratio 2.04; 95% confidence interval: 1.18–3.53) and preterm birth (adjusted Odds Ratio 3.12; 95% confidence interval: 1.97–4.96). Preterm delivery was not associated with S. haematobium infection (adjusted Odds Ratio 1.07 95% confidence interval: 0.57–1.98). In conclusion, this study indicates that pregnant women with urogenital schistosomiasis are at an increased risk for low birth weight deliveries. Further studies evaluating targeted treatment and prevention programmes for urogenital schistosomiasis in pregnant women and their impact on delivery outcomes are warranted.  相似文献   

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Growth dynamics of Pseudomonas aeruginosa, Burkholderia cepacia, and Staphylococcus aureus in a batch and chemostat, were investigated as a laboratory model system for persistent infections in cystic fibrosis. Most species-specific enumeration methods for mixed cultures are laborious or only qualitative, and therefore impede generation of quantitative data required for validation of mathematical models. Here, a quantitative T-RFLP method was evaluated and applied for specific and absolute cell number enumerations. The method was tested to be unbiased by quantitative sample composition and allowed reproducible enumerations of mixed cultures. For assay validation, samples of defined concentration containing one, two or three species were quantified. Logarithmically transformed absolute cell numbers of single-species dilutions were linear within a lower working range of 10(4)-10(6) cfu/mL (species-dependent) and an upper working range of 10(10) cfu/mL. Quantifications of single species (10(6)-10(10) cfu/mL) spiked with one or two other species agreed well with single species controls. Differences between slopes of first order linear regression of spiked and pure dilution series were insignificant. Coefficient of variation of defined mixed replicates was maximum 4.39%, of a three-species chemostat it was maximum 1.76%. T-RFLP monitoring of pure cultures in parallel shake flasks and of a three-species mixed chemostat gave very consistent results. Coexistence of at least two species after a time period equivalent to more than 33 volume exchanges was found. This result was not predicted from pure cultures clearly indicating the need for quantitative mixed culture experiments to better understand microbial growth dynamics and for mathematical model validation.  相似文献   

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The Eurasian badger (Meles meles) is implicated in the transmission of bovine tuberculosis (TB) to cattle in the UK and Republic of Ireland. Badger culling has been employed for the control of TB in cattle in both countries, with varying results. Social perturbation of badger populations following culling has been proposed as an explanation for the failure of culling to consistently demonstrate significant reductions in cattle TB. Field studies indicate that culling badgers may result in increased immigration into culled areas, disruption of territoriality, increased ranging and mixing between social groups. Our analysis shows that some measures of sociality may remain significantly disrupted for up to 8 years after culling. This may have epidemiological consequences because previous research has shown that even in a relatively undisturbed badger population, movements between groups are associated with increases in the incidence of Mycobacterium bovis infection. This is consistent with the results from a large-scale field trial, which demonstrated decreased benefits of culling at the edges of culled areas, and an increase in herd breakdown rates in neighbouring cattle.  相似文献   

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Increased public concern and strict statutory regulations relating tothe generation and exploitation of genetically modified organisms, make itimperative to track accurately individual plants through DNA transformationprogrammes. The ability to rapidly retrieve information associated withspecifictransgenic events and to provide accurate reports on demand is an increasinglyimportant feature for public research laboratories. Transgenic Plant Monitor(TPM) has been developed as a database structured to allow efficient recording,monitoring and analysis of the extensive and complex data generated in planttissue culture and transformation experiments. TPM is built upon the widelyavailable Microsoft Access database engine and can be readily adoptedand/or adapted by other users. The key features and the utility of TPM as aresearch tool are discussed in this article.  相似文献   

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As extinctions continue across the globe, conservation biologists are turning to species reintroduction programs as one optimistic tool for addressing the biodiversity crisis. For repatriation to become a viable strategy, fundamental prerequisites include determining the causes of declines and assessing whether the causes persist in the environment. Invasive species—especially pathogens—are an increasingly significant factor contributing to biodiversity loss. We hypothesized that Batrachochytrium dendrobatidis (Bd), the causative agent of the deadly amphibian disease chytridiomycosis, was important in the rapid (<10 years) localized extirpation of a North American frog (Rana boylii) and that Bd remains widespread among extant amphibians in the region of extirpation. We used an interdisciplinary approach, combining interviews with herpetological experts, analysis of archived field notes and museum specimen collections, and field sampling of the extant amphibian assemblage to examine (1) historical relative abundance of R. boylii; (2) potential causes of R. boylii declines; and (3) historical and contemporary prevalence of Bd. We found that R. boylii were relatively abundant prior to their rapid extirpation, and an increase in Bd prevalence coincided with R. boylii declines during a time of rapid change in the region, wherein backcountry recreation, urban development, and the amphibian pet trade were all on the rise. In addition, extreme flooding during the winter of 1969 coincided with localized extirpations in R. boylii populations observed by interview respondents. We conclude that Bd likely played an important role in the rapid extirpation of R. boylii from southern California and that multiple natural and anthropogenic factors may have worked in concert to make this possible in a relatively short period of time. This study emphasizes the importance of recognizing historical ecological contexts in making future management and reintroduction decisions.  相似文献   

17.
To assess the biodiversity potential of an ungrazed and a grazed inland salt meadow in the Seewinkel (Eastern Austria), spider assemblages were recorded by pitfall trapping for 1 year. Both species assemblages consisted, to a large extent, of rare species of conservation interest. The species assemblage of the grazed site was dominated by Pardosa agrestis, but highly specific halotopobiontic species also occurred in higher numbers. Halotolerant species were also present in the ungrazed meadow, but their individual number was much lower. The species composition of this site reflects the more balanced microclimatical situation of the high sward. Comparison of the two assemblages with 207 other meadow spider assemblages of Central Europe shows a separated position, especially of the grazed site assemblage. High similarities with assemblages of meadows with a similar vegetation structure indicate a high importance of management. Considering the high proportion of rare species on both sites, the best management of the salt meadow and pan shores of the Seewinkel should combine areas of light grazing with ungrazed areas. However, the proportion of these parts and the intensity of grazing still remains to be determined by quantitative experiments.  相似文献   

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BackgroundEsophageal squamous cell carcinoma (ESCC) is common in certain areas worldwide. One area, western Kenya, has a high risk of ESCC, including many young cases (<30 years old), but has limited prior study of potential risk factors. Thermal injury from hot food and beverages and exposure to polycyclic aromatic hydrocarbons (PAHs) have been proposed as important risk factors for ESCC in other settings. The beverage of choice in western Kenya is milky tea (chai).MethodsHealthy individuals >18 years of age who were accompanying relatives to an endoscopy unit were recruited to participate. The preferred initial temperature of chai consumption in these adults was measured by questionnaire and digital thermometer. Comparisons of these results were assessed by kappa statistics. Concentrations of 26 selected PAHs were determined by gas chromatography/mass spectrometry in samples of 11 brands of commercial tea leaves commonly consumed in Kenya.ResultsKappa values demonstrated moderate agreement between questionnaire responses and measured temperatures. The mean preferred chai temperatures were 72.1 °C overall, 72.6 °C in men (n = 78), and 70.2 °C in women (n = 22; p < 0.05). Chai temperature did not significantly differ by age or ethnic group. The PAH levels in the commercial Kenyan tea leaves were uniformly low (total PAH < 300 ng/g of leaves).ConclusionsStudy participants drink chai at higher temperatures than previously reported in other high-risk ESCC regions. Chai is not, however, a source of significant PAH exposure. Very hot chai consumption should be further evaluated as a risk factor for ESCC in Kenya with the proposed questionnaire.  相似文献   

20.
We report the discovery of previously unrecognised short consensus repeats (SCRs) within human and chimpanzee CR1 and CR1L. Analysis of available genomic, protein and expression databases suggests that these are actually genomic remnants of SCRs previously reported in other complement control proteins (CCPs). Comparison with the nucleotide motifs of the 11 defined subfamilies of SCRs justifies the designation g-like because of the close similarity to the g subfamily found in CR2 and MCP. To date, we have identified five such SCRs in human and chimpanzee CR1, one in human and chimpanzee CR1L, but none in either rat or mouse Crry in keeping with the number of internal duplications of the long homologous repeat (LHR) found in CR1 and CR1L. In fact, at the genomic level, the ancestral LHR must have contained eight SCRs rather than seven as previously thought. Since g-like SCRs are found immediately downstream of d SCRs, we suggest that there must have been a functional dg set which has been retained by CR2 and MCP but which is degenerate in CR1 or CR1L. Interestingly, dg is also present in the CR2 component of mouse CR1. The degeneration of the g SCR must have occurred prior to the formation of primate CR1L and prior to the duplication events which resulted in primate CR1. In this context, the apparent conservation of g-like SCRs may be surprising and may suggest the existence of mechanisms unrelated to protein coding. These results provide examples of the many processes which have contributed to the evolution of the extensive repertoire of CCPs.  相似文献   

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