1,386 research outputs found

    A large-stroke planar 2-DOF flexure-based positioning stage for vacuum environments

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    The growing demand from industry for high-precision systems introduces new challenges for positioning mechanisms. High accuracy and repeatability down\ud to the sub-micron scale are not uncommon. This is often combined with extreme environments, like high UV light sources, electron beams or vacuum. This\ud article focuses on the flexure mechanism for a largestroke planar XY-positioning system. Applications for such a flexure mechanism can be found in for example lithography, micromachining or microscopy

    Proportion of various types of thyroid disorders among newborns with congenital hypothyroidism and normally located gland: A regional cohort study

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    Objective To determine the proportion of the various types of thyroid disorders among newborns detected by the neonatal TSH screening programme, with a normally located thyroid gland.Patients and methods Of the 882 575 infants screened in our centre between 1981 and 2002, 85 infants with a normally located gland had persistent elevation of serum TSH values (an incidence of 1/10 383). Six of these 85 patients were lost to follow-up and were therefore excluded from the study. During follow-up, patients were classified as having permanent or transient hypothyroidism.Results Among the 79 patients included in the study, transient (n = 30, 38% of cases) and permanent (n = 49, 62% of cases) congenital hypothyroidism (CH) was demonstrated during the follow-up at the age of 0.7 +/- 0.6 years and 2.6 +/- 1.8 years (P < 0.0001), respectively. The proportion of premature births was significantly higher in the group with transient CH (57%) than in the group with permanent CH (2%) (P < 0.0001). A history of iatrogenic iodine overload was identified during the neonatal period in 69% of transient cases. Among permanent CH cases (n = 49), patients were classified as having a goitre (n = 27, 55% of cases), a normal sized and shaped thyroid gland (n = 14, 29% of cases) or a hypoplastic gland (n = 8, 16% of cases). The latter patients demonstrated global thyroid hypoplasia (n = 3), a right hemithyroid (n = 2), hypoplasia of the left lobe (n = 2), or asymmetry in the location of the two lobes (n = 1). Patients with a normal sized and shaped thyroid gland showed a significantly less severe form of hypothyroidism than those with a goitre or a hypoplastic thyroid gland (P < 0.0002). Among permanent CH cases, those with a goitre (n = 27) had an iodine organification defect (n = 10), Pendred syndrome (n = 1), a defect of thyroglobulin synthesis (n = 8), or a defect of sodium iodine symporter (n = 1), and in seven patients no aetiology could be determined. Among permanent cases with a normal sized and shaped thyroid gland (n = 14), a specific aetiology was found in only one patient (pseudohypoparathyroidism) and two patients had Down's syndrome. Among those with a globally hypoplastic gland, a TSH receptor gene mutation was found in two patients.Conclusions A precise description of the phenotype can enhance our understanding of various forms of neonatal hypothyroidism as well as their prevalence and management. It also helps to identify cases of congenital hypothyroidism of unknown aetiology, which will need to be investigated in collaboration with molecular biologists

    Intergenerational correlations in size at birth and the contribution of environmental factors: The Uppsala Birth Cohort Multigenerational Study, Sweden, 1915-2002.

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    Sizes at birth of parents and their children are known to be correlated, reflecting in part the influence of fetal and maternal genes. Sociodemographic factors, regarded as aspects of the shared environment across generations, would also be expected to contribute, but evidence is limited. In the present study, the authors aimed to quantify the role of the shared environment in explaining intergenerational correlations in birth weight and length by using data across 3 consecutive generations from the Uppsala Birth Cohort Multigenerational Study in Uppsala, Sweden. That study included birth and sociodemographic data on 7,657 singletons born in Uppsala in 1915-1929 (generation 1) and their grandchildren (generation 3). Standard regression and biometric models were used to study the correlations in size at birth of generation 1-generation 3 pairs. The data showed stronger correlations in maternal pairs than in paternal pairs for birth weight (0.125 vs. 0.096, P = 0.02) but not for birth length (0.097 vs. 0.093, P = 0.77). These correlations were not reduced by adjustment for sociodemographic factors in regression models. In contrast, significant shared-environment contributions to the intergenerational correlations were identified in biometric models, averaging 14% for both birth measures. These models assumed a common latent factor for the sociodemographic variables. The present results show that the shared environment moderately but significantly contributes to intergenerational correlations

    Impact of Summer Cattle Grazing on the Sierra Nevada Watershed: Aquatic Algae and Bacteria

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    Introduction. We evaluated periphytic algal and microbial communities to assess the influence of human and cattle impact on Sierra water quality. Methods. 64 sites (lakes and streams from Lake Tahoe to Sequoia National Park, California) were sampled for suspended indicator bacteria and algae following standardized procedures. The potential for nonpoint pollution was divided into three categories: cattle-grazing areas (C), recreation use areas (R), or remote wildlife areas (W). Results. Periphyton was found at 100% of C sites, 89% of R sites, but only 25% of W sites. Eleven species of periphytic algae were identified, including Zygnema, Ulothrix, Chlorella, Spirogyra, mixed Diatoms, and Cladophoria. Mean benthic algae coverage was 66% at C sites compared to 2% at W sites (P < 0.05). The prevalence of E. coli associated with periphyton was 100% at C sites, 25% of R sites, and 0% of W sites. Mean E. coli CFU/gm of algae detected was: C = 173,000, R = 700, W = 0. (P < 0.05). Analysis of neighboring water for E. coli bacteria >100 CFU/100 mL: C = 91%, R = 8%, W = 0 (P < 0.05). Conclusion. Higher periphytic algal biomass and uniform presence of periphyton-attached E. coli corresponded to watersheds exposed to summer cattle grazing. These differences suggest cattle grazing compromises water quality

    Sorting of chromosomes by magnetic separation

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    Chromosomes were isolated from Chinese hamster x human hybrid cell lines containing four and nine human chromosomes. Human genomic DNA was biotinylated by nick translation and used to label the human chromosomes by in situ hybridization in suspension. Streptavidin was covalently coupled to the surface of magnetic beads and these were incubated with the hybridized chromosomes. The human chromosomes were bound to the magnetic beads through the strong biotin-streptavidin complex and then rapidly separated from nonlabeled Chinese hamster chromosomes by a simple permanent magnet. The hybridization was visualized by additional binding of avidin-FITC (fluorescein) to the unoccupied biotinylated human DNA bound to the human chromosomes. After magnetic separation, up to 98% of the individual chromosomes attached to magnetic beads were classified as human chromosomes by fluorescence microscopy

    Developing markets? Understanding the role of markets and development at the intersection of macromarketing and transformative consumer research (TCR)

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    Situated at the intersection of markets and development, this commentary aims to promote a cross-fertilization of macromarketing and Transformative Consumer Research (TCR) that directs attention to the sociocultural context and situational embeddedness of consumer experience and well-being, while acknowledging complex, systemic interdependencies between markets, marketing, and society. Based on a critical review of the meaning of development and an interrogation of various developmental discourses, the authors develop a conceptual framework that brings together issues of development, well-being, and social inequalities. We suggest that these issues are better understood and addressed when examined via grounded investigations of the role of markets in shaping the management of resources, consumer agency, power inequalities and ethics. The use of markets as units of analysis may lead to further cross-fertilizations of TCR and macromarketing and to more comprehensive theorizing and transformational impact. Two empirical cases are provided to illustrate our framework

    The effect of microcredit on women's control over household spending in developing countries: a systematic review

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    Background: Over the past three decades, microfinance activities have spread across the globe, reaching tens of millions of poor households with tailored financial services. Microfinance can best be described as a field of intervention rather than a particular instrument. Initially, microfinance usually meant microcredit for working capital and very small investments, but increasingly it has been broadened to include savings/deposits, a limited range of micro-insurance and payment services (including micro-leasing) as well as a somewhat broader range of credit products for more substantial investments. In this study we focused on microcredit activities, constituting the bulk of microfinance activities across the globe. Microcredit activities have affected the lives of clients and others in multiple ways. The most frequently reported types of effects of credit at individual, enterprise and household level are the following: income, expenditure smoothing, and poverty alleviation effects; business growth and employment effects; schooling effects; and effects in terms of women's empowerment. Despite the diversity in microcredit schemes, many share two characteristics: they target poor women and often rely on some type of group-based lending. Women's empowerment in relation to microcredit has been studied extensively within the context of this type of microcredit scheme. Most of these studies have been carried out in the context of microcredit group schemes in South Asia. It has been argued that access to microcredit can foster changes in individual attitudes of women (e.g. increased self-reliance), power relations within the household (e.g. control over resources) and social status. An important dimension of empowerment concerns women's control over household spending. The main assumption is that by providing credit to poor women, their direct control over expenditures within the household increases, with subsequent implications for the status of women and the well-being of women and other household members. Women's control over household spending is a frequently recurring aspect analyzed within the context of microcredit interventions, which allows us to study whether microcredit targeted at women affects women's control over household spending decisions and the circumstances in which this occurs. Despite the central and recurrent role across studies of this aspect of women's empowerment in relation to microcredit activities, there has been no previous review on this topic. The growing importance of microcredit has resulted in a vast number of research and evaluation studies, including impact studies. Consequently, the microfinance literature harbors a substantial number of synthesis studies which discuss a set of microcredit interventions and aim to generate overall conclusions on their effects. However, most of these studies face limitations in terms of depth of empirical assessment and the extent to which the identified effects can be attributed to microcredit. Moreover, methodological principles regarding comprehensive searches and principles of selection, coding, extraction and aggregation are often lacking in review studies. Partial exceptions are three recent systematic reviews which all differ in scope from the present one (Stewart et al., 2010; Duvendack et al. 2011; Stewart et al., 2012). The reviews respectively focus on microfinance (credit and savings) in Sub-Sahara Africa, microcredit worldwide, and microfinance worldwide (credit, saving and leasing). Overall, these reviews suggest that the effects of microcredit on women's empowerment are at best mixed. In part this can be explained by the heterogeneity in microcredit interventions, contexts and target groups. However, the existing reviews did not use statistical meta-analysis to synthesise evidence of effects, nor context-mechanism-outcome synthesis to understand the variation in effects. Objectives: The main objective of this study was to provide a systematic review of the evidence on the effects of microcredit on women's control over household spending in developing countries. More specifically, we aimed to answer two related research questions: 1) what does the impact evaluative evidence say about the causal relationship between microcredit and specific dimensions of women's empowerment (women'ss control over household spending); and 2) what are the mechanisms which mediate this relationship. We prioritise depth of analysis over breadth, thus the scope of this review is narrower than previous systematic reviews on microfinance (Stewart et al., 2010; Duvendack et al. 2011; Stewart et al., 2012). We focused on specific aspects of women's empowerment which allowed us to combine statistical meta-analysis and realist (context-mechanism-outcome) synthesis. Criteria for considering studies for this review: We included studies that analyzed the effects of microcredit schemes targeting poor women in low and middle income countries, as defined by the World Bank. Studies that did not include analysis on microcredit and the effect on one or more dimensions (specified in main body of the report) of women's control over household expenditures were excluded. Studies which gave evidence of addressing the attribution problem either through randomised design, quasi-experimental matching, or regression analysis, were included. In practice, women's control over household spending (as a key dimension of empowerment) is influenced by many different factors. By focusing on those studies which explicitly addressed the challenge of separating the effect of microcredit from other influencing factors, we developed what we consider to be the most credible evidence base for drawing conclusions about the effects of microcredit on women's control over household expenditures in different contexts. SEARCH STRATEGY We conducted a comprehensive search covering all relevant academic databases, internet search engines and web sites with published and unpublished research, and also carried out extensive manual searches of books and additional journals not included in electronic data bases (searches were concluded on December 31, 2011). We used back-referencing from recent studies as well as citation-tracking to identify additional relevant studies. Finally, authors of studies which we were unable to retrieve were contacted. In addition, we contacted experts on microcredit and women's empowerment for additional references which we might have missed. Search strategies in databases and journals were adapted for each source. Where possible we used the existing keyword indices of particular databases. In addition, we applied our own list of combinations of keywords covering all relevant terms relating to the independent variable (i.e. credit and its variations) and the dependent variable (i.e. dimensions of women's control over household spending, empowerment). Data collection and analysis: From the different searches we identified an initial number of 310 papers that were selected for full text examination. Eventually, 29 papers were retained for further analysis, corresponding to 25 unique studies. These 25 independent findings were included in the synthesis. However, based on a systematic risk of bias assessment we found that more than half of the included studies had high threats to internal validity. Moreover, only about half of the studies show a clear and coherent link between a theoretical framework on microcredit and women's control over household spending and empirical data analysis. It should be noted that reviewing and synthesizing quantitative results from studies is only one side of the coin. The other side is to understand what makes them work, or what prevents them from working. Consequently, we conducted a qualitative synthesis of the included studies, which focused on identifying the mechanisms which underlie the causal relationship between microcredit and women's control over household spending. RESULTS The results of the meta-analysis indicated that the effect sizes from experimental studies examining effects of microcredit on women's control over household spending are not statistically significantly different from zero. The effects from quasi-experimental studies are statistically insignificant overall, and at best of small magnitude for those studies assessed of being of high risk of bias. We conclude that there is no consistent evidence for an effect of microcredit on women's control over household spending. In the qualitative analysis, using Coleman's (1986, 1990) typology of mechanisms, we identified five different situational mechanisms and eight different action-formation mechanisms. Due to the combination of substantial heterogeneity in contexts (e.g. existing gender relations) and interventions (e.g. microcredit versus microcredit and additional services), and the lack of information in the studies on this heterogeneity, it was not possible to go beyond the identification of mechanisms, in terms of generating empirically tested articulated theories of change which are representative beyond a specific study context. Authors' conclusions: In line with three recent other reviews on microfinance (Stewart et al., 2010; Duvendack et al., 2011; Stewart et al. 2012) we found that the microcredit evidence base is extensive, yet most studies are weak methodologically. From those studies deemed comparable and of minimum acceptable quality, we concluded that overall there is no evidence for an effect of microcredit on women's control over household spending. Women's control over household resources constitutes an important intermediary dimension in processes of women's empowerment. Given the overall lack of evidence for an effect of microcredit on women's control over household resources it is therefore very unlikely that, overall, microcredit has a meaningful and substantial impact on empowerment processes in a broader sense. While impacts on empowerment may appear to have occurred in particular studies, the high risk of bias of studies providing positive assessments suggests that such findings are of limited validity. Our conclusions on the effects of microcredit on empowerment are also in line with previous systematic reviews by Duvendack et al. (2011) and Stewart (et al. 2010) who report to a limited extent on empowerment effects. Consequently, there appears to be a gap between the often optimistic societal belief in the capacity of microcredit to ameliorate the position of women in decision-making processes within the household on the one hand, and the empirical evidence base on the other hand. However, our review markedly differs from previous reviews in two regards. First, we specifically focused on microcredit and women's empowerment captured through women's control over household expenditures. Second, as a result of this narrower focus, we were able to conduct statistical meta-analysis and extract behavioral mechanisms which can help to explain why and how microcredit can make a difference. The advantage of our approach was that the identified mechanisms all stem from studies which show evidence of addressing the attribution problem. Consequently, we can be quite confident of the insights that they provided on the effects of microcredit on women's control over household spending for particular populations of microcredit female clients and their families. Those studies that showed evidence of addressing the attribution problem were relatively weak on underlying theory. Moreover, they often lacked essential information such as the nature of the intervention and how it related to empowerment (e.g. how solidarity groups affect empowerment processes) or the slowly evolving gender relations in different contexts (e.g. the evolution of societal norms and the relationship with power relations in the household). A next logical step would be to undertake a systematic review of qualitative studies which often provide rich and context-specific information on microcredit and women's decision-making power in the household. Such a review should ideally build on the mechanisms identified in the present review and would bring us closer to uncovering credible theories of microcredit and the circumstances in which it may change women's decision-making power

    The signature of fine scale local adaptation in Atlantic salmon revealed from common garden experiments in nature

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    Understanding the extent, scale and genetic basis of local adaptation (LA) is important for conservation and management. Its relevance in salmonids at microgeographic scales, where dispersal (and hence potential gene flow) can be substantial, has however been questioned. Here, we compare the fitness of communally reared offspring of local and foreign Atlantic salmon Salmo salar from adjacent Irish rivers and reciprocal F-1 hybrid crosses between them, in the wild home\u27 environment of the local population. Experimental groups did not differ in wild smolt output but a catastrophic flood event may have limited our ability to detect freshwater performance differences, which were evident in a previous study. Foreign parr exhibited higher, and hybrids intermediate, emigration rates from the natal stream relative to local parr, consistent with genetically based behavioural differences. Adult return rates were lower for the foreign compared to the local group. Overall lifetime success of foreigners and hybrids relative to locals was estimated at 31% and 40% (mean of both hybrid groups), respectively. The results imply a genetic basis to fitness differences among populations separated by only 50km, driven largely by variation in smolt to adult return rates. Hence even if supplementary stocking programs obtain broodstock from neighbouring rivers, the risk of extrinsic outbreeding depression may be high

    Characterization of Prion Disease Associated with a Two-Octapeptide Repeat Insertion

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    Genetic prion disease accounts for 10–15% of prion disease. While insertion of four or more octapeptide repeats are clearly pathogenic, smaller repeat insertions have an unclear pathogenicity. The goal of this case series was to provide an insight into the characteristics of the 2-octapeptide repeat genetic variant and to provide insight into the risk for Creutzfeldt–Jakob disease in asymptomatic carriers. 2-octapeptide repeat insertion prion disease cases were collected from the National Prion Disease Pathology Surveillance Center (US), the National Prion Clinic (UK), and the National Creutzfeldt–Jakob Disease Registry (Australia). Three largescale population genetic databases were queried for the 2-octapeptide repeat insertion allele. Eight cases of 2-octapeptide repeat insertion were identified. The cases were indistinguishable from the sporadic Creutzfeldt–Jakob cases of the same molecular subtype. Western blot characterization of the prion protein in the absence of enzymatic digestion with proteinase K revealed that 2-octapeptide repeat insertion and sporadic Creutzfeldt–Jakob disease have distinct prion protein profiles. Interrogation of large-scale population datasets suggested the variant is of very low penetrance. The 2-octapeptide repeat insertion is at most a low-risk genetic variant. Predictive genetic testing for asymptomatic blood relatives is not likely to be justified given the low risk
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