271 research outputs found

    Comparative biometrics of British marsh tits Poecile palustris and willow tits P. montana

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    Biometrics are commonly used to compare bird species. For Marsh Tits and Willow Tits in Britain there are few biometric data from birds of known age and sex, despite their value for population analyses in estimating the proportion of males and females in samples. Comparing measurements between the two species could also aid identification and the monitoring of these declining species in Britain. We present biometrics for a large sample of Marsh Tits of known age and sex, and new data for Willow Tits, which act as reliable reference material. Overall, adults of both species were larger than first-years and males were larger than females, but not among first-year Willow Tits. Marsh Tits were slightly larger and heavier than Willow Tits, but Willow Tits had proportionately longer tails. Discriminant analyses produced new equations for separating the species based on wing length and the measurement between the shortest and longest tail feathers. Probabilities were generated for estimating Marsh Tit population structure from samples of ringing data, but there was a greater overlap between sexes in Willow Tit measurements. We conclude by discussing issues of measurement accuracy and consistency in the collection and analysis of biometric data

    Insights into the mechanism for gold catalysis: behaviour of gold(i) amide complexes in solution

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    We report the synthesis and activity of new mononuclear and dinuclear gold amide complexes . The dinuclear complexes and were characterised by single crystal X-ray analysis. We also report solution NMR and freezing point depression experiments to rationalise their behaviour in solution and question the de-ligation process invoked in gold catalysis

    Applicant Reactions to the AAMC Standardized Video Interview During the 2018 Application Cycle

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    PURPOSE: This study examined applicant reactions to the Association of American Medical Colleges (AAMC) Standardized Video Interview (SVI) during its first year of operational use in emergency medicine (EM) residency program selection in order to identify strategies to improve applicants\u27 SVI experience and attitudes. METHOD: Individuals who self-classified as EM applicants applying in the Electronic Residency Application Service 2018 cycle and completed the SVI in summer 2017 were invited to participate in two surveys. Survey 1, which focused on procedural issues, was administered immediately after SVI completion. Survey 2, which focused on applicants\u27 SVI experience, was administered in fall 2017, after SVI scores were released. RESULTS: The response rates for surveys 1 and 2 were 82.3% (2,906/3,532) and 58.7% (2,074/3,532), respectively. Applicant reactions varied by aspect of the SVI studied and their SVI total scores. Most applicants were satisfied with most procedural aspects of the SVI, but most applicants were not satisfied with the SVI overall or with their total SVI scores. About 20-30% of applicants had neutral opinions about most aspects of the SVI. Negative reactions to the SVI were stronger for applicants who scored lower on the SVI. CONCLUSIONS: Applicants had generally negative reactions to the SVI. Most were skeptical of its ability to assess the target competencies and its potential to add value to the selection process. Applicant acceptance and appreciation of the SVI will be critical to the SVI\u27s acceptance by the graduate medical education community

    Maternal–Fetal Microtransfusions and HIV-1 Mother-to-Child Transmission in Malawi

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    Background: Between 25% and 35% of infants born to HIV-infected mothers become HIV-1 infected. One potential route of mother-to-child transmission (MTCT) could be through a breakdown in the placental barrier (i.e., maternal–fetal microtransfusions). Methods and Findings: Placental alkaline phosphatase (PLAP) is a 130-kD maternal enzyme that cannot cross the intact placental barrier. We measured PLAP activity in umbilical vein serum as an indicator of maternal–fetal microtransfusion, and related this to the risk of HIV-1 MTCT. A case-cohort study was conducted of 149 women randomly selected from a cohort of HIV-1-infected pregnant Malawians; these women served as a reference group for 36 cases of in utero MTCT and 43 cases of intrapartum (IP) MTCT. Cord PLAP activity was measured with an immunocatalytic assay. Infant HIV status was determined by real-time PCR. The association between cord PLAP activity and HIV-1 MTCT was measured with logistic regression using generalized estimating equations. Among vaginal deliveries, PLAP was associated with IP MTCT (risk ratio, 2.25 per log10log_{10} ng/ml PLAP; 95% confidence interval, 0.95–5.32) but not in utero MTCT. In a multivariable model adjusted for HIV-1 RNA load, chorioamnionitis, and self-reported fever, the risk of IP MTCT almost tripled for every log10log_{10} increase in cord PLAP activity (risk ratio, 2.87; 95% confidence interval, 1.05–7.83). Conclusion: These results suggest that during vaginal deliveries, placental microtransfusions are a risk factor for IP HIV-1 MTCT. Future studies are needed to identify factors that increase the risk for microtransfusions in order to prevent IP HIV-1 MTCT

    Reclaiming the political : emancipation and critique in security studies

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    The critical security studies literature has been marked by a shared commitment towards the politicization of security – that is, the analysis of its assumptions, implications and the practices through which it is (re)produced. In recent years, however, politicization has been accompanied by a tendency to conceive security as connected with a logic of exclusion, totalization and even violence. This has resulted in an imbalanced politicization that weakens critique. Seeking to tackle this situation, the present article engages with contributions that have advanced emancipatory versions of security. Starting with, but going beyond, the so-called Aberystwyth School of security studies, the argument reconsiders the meaning of security as emancipation by making the case for a systematic engagement with the notions of reality and power. This revised version of security as emancipation strengthens critique by addressing political dimensions that have been underplayed in the critical security literature

    Mutations Associated with Sulfadoxine-Pyrimethamine and Chlorproguanil Resistance in Plasmodium falciparum Isolates from Blantyre, Malawi

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    We conducted a prevalence study of mutations in Plasmodium falciparum that are associated with antifolate resistance in Blantyre, Malawi. The dihydrofolate reductase 164-Leu mutation, which confers resistance to both pyrimethamine and chlorproguanil, was found in 4.7% of the samples. Previously unreported mutations in dihydropteroate synthase were also found

    Maternal–Fetal Microtransfusions and HIV-1 Mother-to-Child Transmission in Malawi

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    BACKGROUND: Between 25% and 35% of infants born to HIV-infected mothers become HIV-1 infected. One potential route of mother-to-child transmission (MTCT) could be through a breakdown in the placental barrier (i.e., maternal–fetal microtransfusions). METHODS AND FINDINGS: Placental alkaline phosphatase (PLAP) is a 130-kD maternal enzyme that cannot cross the intact placental barrier. We measured PLAP activity in umbilical vein serum as an indicator of maternal–fetal microtransfusion, and related this to the risk of HIV-1 MTCT. A case-cohort study was conducted of 149 women randomly selected from a cohort of HIV-1-infected pregnant Malawians; these women served as a reference group for 36 cases of in utero MTCT and 43 cases of intrapartum (IP) MTCT. Cord PLAP activity was measured with an immunocatalytic assay. Infant HIV status was determined by real-time PCR. The association between cord PLAP activity and HIV-1 MTCT was measured with logistic regression using generalized estimating equations. Among vaginal deliveries, PLAP was associated with IP MTCT (risk ratio, 2.25 per log(10) ng/ml PLAP; 95% confidence interval, 0.95–5.32) but not in utero MTCT. In a multivariable model adjusted for HIV-1 RNA load, chorioamnionitis, and self-reported fever, the risk of IP MTCT almost tripled for every log(10) increase in cord PLAP activity (risk ratio, 2.87; 95% confidence interval, 1.05–7.83). CONCLUSION: These results suggest that during vaginal deliveries, placental microtransfusions are a risk factor for IP HIV-1 MTCT. Future studies are needed to identify factors that increase the risk for microtransfusions in order to prevent IP HIV-1 MTCT

    Highly diastereoselective synthesis of substituted pyrrolidines using a sequence of azomethine ylide cycloaddition and nucleophilic cyclization

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    Abstract: Although cycloadditions of azomethine ylides usually give mixtures of endo/exo adducts, we successfully tuned the mechanistic path of a new reaction cascade to afford substituted pyrrolidines in high yields and diastereomeric purity. This was achieved by forcing the demetalation of tin- or silicon-substituted iminium ions, followed by azomethine ylide cycloaddition and nucleophilic cyclization. Structural complexity is thus built rapidly in a fully controlled one-pot reaction cascade

    Decreasing Burden of Malaria in Pregnancy in Malawian Women and Its Relationship to Use of Intermittent Preventive Therapy or Bed Nets

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    The World Health Organization recommends insecticidal bednets and intermittent preventive treatment to reduce malaria in pregnancy. Longitudinal data of malaria prevalence and pregnancy outcomes are valuable in gauging the impact of these antimalarial interventions.We recruited 8,131 women delivering in a single Malawian hospital over 9 years. We recorded demographic data, antenatal prescription of intermittent preventive therapy during pregnancy with sulfadoxine-pyrimethamine and bed net use, and examined finger-prick blood for malaria parasites and hemoglobin concentration. In 4,712 women, we examined placental blood for malaria parasites and recorded the infant's birth weight. Peripheral and placental parasitemia prevalence declined from 23.5% to 5.0% and from 25.2% to 6.8% respectively. Smaller declines in prevalence of low birth weight and anemia were observed. Coverage of intermittent preventive treatment and bednets increased. Number of sulfadoxine-pyrimethamine doses received correlated inversely with placental parasitemia (Odds Ratio (95% CI): 0.79 (0.68, 0.91)), maternal anemia (0.81, (0.73, 0.90)) and low birth weight from 1997-2001 (0.63 (0.53, 0.75)), but not from 2002-2006. Bednet use protected from peripheral parasitemia (0.47, (0.37, 0.60)) and placental parasitemia (0.41, (0.31, 0.54)) and low birth weight (0.75 (0.59, 0.95)) but not anemia throughout the study. Compared to women without nets who did not receive 2-dose sulfadoxine-pyrimethamine, women using nets and receiving 2-dose sulfadoxine-pyrimethamine were less likely to have parasitemia or low birth weight babies. Women receiving 2-dose sulfadoxine-pyrimethamine alone had little evidence of protection whereas bednets alone gave intermediate protection.Increased bednet coverage explains changes in parasitemia and birth weight among pregnant women better than sulfadoxine-pyrimethamine use. High bed net coverage, and sulfadoxine-pyrimethamine resistance, may be contributing to its apparent loss of effectiveness

    Agency, Values, and Well-Being: A Human Development Model

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    This paper argues that feelings of agency are linked to human well-being through a sequence of adaptive mechanisms that promote human development, once existential conditions become permissive. In the first part, we elaborate on the evolutionary logic of this model and outline why an evolutionary perspective is helpful to understand changes in values that give feelings of agency greater weight in shaping human well-being. In the second part, we test the key links in this model with data from the World Values Surveys using ecological regressions and multi-level models, covering some 80 societies worldwide. Empirically, we demonstrate evidence for the following sequence: (1) in response to widening opportunities of life, people place stronger emphasis on emancipative values, (2) in response to a stronger emphasis on emancipative values, feelings of agency gain greater weight in shaping people’s life satisfaction, (3) in response to a greater impact of agency feelings on life satisfaction, the level of life satisfaction itself rises. Further analyses show that this model is culturally universal because taking into account the strength of a society’s western tradition does not render insignificant these adaptive linkages. Precisely because of its universality, this is indeed a ‘human’ development model in a most general sense
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