4,060 research outputs found

    I\u27ll Be Your Regular Sweetie : But I Won\u27t Be Your Once In A While

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    https://digitalcommons.library.umaine.edu/mmb-vp/1752/thumbnail.jp

    The Distribution of Mating-Type Bias in Natural Populations of the Anther-Smut Ustilago violacea on Silene alba in Virginia

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    This is the publisher's version, also available electronically from http://www.jstor.org/stable/info/3761395.Complete individual-wide mating-type bias (retrieval of sporidia of only one mating type from germinated teliospores of one fungal individual) was observed to be a common and widespread feature of the anther-smut fungus, Ustilago violacea, collected from natural populations of its host, Silene alba. The bias was usually to mating type A1, but the frequency of bias and its spatial distribution varied from region to region. Populations with high frequencies of bias still showed high rates of disease transmission. Crosses between A1 mating type sporidial lines from completely biased individuals and A2 mating types from unbiased individuals showed no bias in the progeny. During teliospore germination, biased individuals often showed conjugation among adjacent cells of the promycelium, suggesting that both mating types are present in the germinating teliospore but one mating type is unable to grow as free-living sporidia. The complete bias was most readily interpreted as evidence of "haploid lethals" linked to mating type that cause poor survival or growth of the sporidial stage. The results show that such "haploid lethals" may be a common occurrence in natural populations, and that fungal mating systems may vary considerably over short distances

    Major epidemiological changes in sudden infant death syndrome : a 20-year population-based study in the UK

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    Background Results of case-control studies in the past 5 years suggest that the epidemiology of sudden infant death syndrome (SIDS) has changed since the 1991 UK Back to Sleep campaign. The campaign's advice that parents put babies on their back to sleep led to a fall in death rates. We used a longitudinal dataset to assess these potential changes. Methods Population-based data from home visits have been collected for 369 consecutive unexpected infant deaths (300 SIDS and 69 explained deaths) in Avon over 20 years (1984—2003). Data obtained between 1993 and 1996 from 1300 controls with a chosen “reference” sleep before interview have been used for comparison. Findings Over the past 20 years, the proportion of children who died from SIDS while co-sleeping with their parents, has risen from 12% to 50% (p<0·0001), but the actual number of SIDS deaths in the parental bed has halved (p=0·01). The proportion seems to have increased partly because the Back to Sleep campaign led to fewer deaths in infants sleeping alone—rather than because of a rise in deaths of infants who bed-shared, and partly because of an increase in the number of deaths in infants sleeping with their parents on a sofa. The proportion of deaths in families from deprived socioeconomic backgrounds has risen from 47% to 74% (p=0·003), the prevalence of maternal smoking during pregnancy from 57% to 86% (p=0·0004), and the proportion of pre-term infants from 12% to 34% (p=0·0001). Although many SIDS infants come from large families, first-born infants are now the largest group. The age of infants who bed-share is significantly smaller than that before the campaign, and fewer are breastfed. Interpretation Factors that contribute to SIDS have changed in their importance over the past 20 years. Although the reasons for the rise in deaths when a parent sleeps with their infant on a sofa are still unclear, we strongly recommend that parents avoid this sleeping environment. Most SIDS deaths now occur in deprived families. To better understand contributory factors and plan preventive measures we need control data from similarly deprived families, and particularly, infant sleep environments

    African traditional abdominal massage in pregnancy resulting in antepartum uterine rupture, abruptio placenta and foetal demise – a case report

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    The practice of abdominal massage dates to years ago and associated with foetal and maternal morbidity and mortality when undertaken by untrained traditional birth attendants in our setting. We present a 30-year old G3P2+0 with uterine rupture and intra-uterine foetal death following abdominal massage. She was resuscitated and had emergency exploratory laparotomy and repair of uterine rupture

    XMM-Newton observations of the eastern jet of SS433

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    The radio supernova remnant W50 hosts at its center the peculiar galactic X-ray binary SS 433. It shows a central spherical structure with two `ears' which are supposed to be formed by the interaction of the precessing jets of SS 433 with the supernova shell. In two pointings in September/October 2004 for 30 ks each the eastern jet of SS 433 was observed with XMM-Newton to study the outermost parts of the `ear' and the X-ray bright emission region about 35 arcmin from SS 433. The spectra consist of two components: a non-thermal power law with photon index \Gamma ~ 2.17+/-0.02 and a thermal component at a typical temperature of kT ~ 0.3 keV. The X-ray emission seems to fill the whole interior region of the radio remnant W50. The jet terminates in the eastern `ear' in a ring-like terminal shock which indicates a flow with a kind of hollow-cone morphology. The spatial coincidence of X-ray and radio emission suggests physical conditions similar to those found at the outer shocks of ordinary supernova remnants. The bright emission region closer to SS 433 radiates non-thermally in a spatially well confined geometry at higher X-ray energies. At soft X-rays the shape of the region gets blurred, centered on the hard lenticular emission. The shape of this region and the bend in the jet propagation direction might be caused by the interaction of a re-collimated jet with the outer, non homogeneous interstellar matter distribution. The physical conditions leading to the re-collimation of the jet and the peculiar emission morphology are far from being understood and require deeper observations as well as a detailed modeling of the interaction of a jet with its surroundings.Comment: 10 pages, 8 figures, to appear in A&

    Angular distribution studies on the two-photon ionization of hydrogen-like ions: Relativistic description

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    The angular distribution of the emitted electrons, following the two-photon ionization of the hydrogen-like ions, is studied within the framework of second order perturbation theory and the Dirac equation. Using a density matrix approach, we have investigated the effects which arise from the polarization of the incoming light as well as from the higher multipoles in the expansion of the electron--photon interaction. For medium- and high-Z ions, in particular, the non-dipole contributions give rise to a significant change in the angular distribution of the emitted electrons, if compared with the electric-dipole approximation. This includes a strong forward emission while, in dipole approxmation, the electron emission always occurs symmetric with respect to the plane which is perpendicular to the photon beam. Detailed computations for the dependence of the photoelectron angular distributions on the polarization of the incident light are carried out for the ionization of H, Xe53+^{53+}, and U91+^{91+} (hydrogen-like) ions.Comment: 16 pages, 4 figures, published in J Phys

    The RCSB Protein Data Bank: views of structural biology for basic and applied research and education.

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    The RCSB Protein Data Bank (RCSB PDB, http://www.rcsb.org) provides access to 3D structures of biological macromolecules and is one of the leading resources in biology and biomedicine worldwide. Our efforts over the past 2 years focused on enabling a deeper understanding of structural biology and providing new structural views of biology that support both basic and applied research and education. Herein, we describe recently introduced data annotations including integration with external biological resources, such as gene and drug databases, new visualization tools and improved support for the mobile web. We also describe access to data files, web services and open access software components to enable software developers to more effectively mine the PDB archive and related annotations. Our efforts are aimed at expanding the role of 3D structure in understanding biology and medicine

    Minimally Invasive Treatment of Spinal Metastases: Techniques

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    With improved treatments and increasingly life expectancy, the burden of metastatic disease in the spine is expected to rise. The role of conventional surgery for spinal metastases is well established but often involves procedures of large magnitude. We describe minimally invasive techniques for spinal stabilization and decompression in patients with symptomatic metastatic disease of the spine

    Maternal serum lactate dehydrogenase level as a predictor of adverse pregnancy outcome in women with severe preeclampsia

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    Background: Preeclampsia is a multisystem disorder causing vascular endothelial damage and leads to leakage of lactate dehydrogenase (LDH) into maternal serum. This study evaluated the serum LDH levels in severe preeclamptic women to detect any correlation with adverse pregnancy outcomes. Methods: A prospective cohort study compared LDH levels of 68 severe preeclamptic women with 68 normotensives in the third trimester, matched for age, parity, and gestational age. The preeclamptic women were followed up until delivery to assess the maternal and neonatal outcomes. Data were analyzed with SPSS for Windows version 23. The level of significance was set at p&lt;0.05. Results: Both groups were comparable in their characteristics. The mean LDH level for severe preeclamptic group (717.40 IU/L) was higher than for the normotensive group (162.90 IU/L) and this was significant (p=0.001). Cesarean delivery was less likely when LDH was &gt;600 compared to ≤600 (OR 0.31; p=0.049) indicating a potential protective effect. The likelihood of IUGR (OR 3.14; p=0.045), IUFD (OR 6.48; p=0.028), stillbirth (OR 7.06 p=0.007), perinatal mortality (OR 4.84; p=0.004) and low birth weight &lt;2500 gm (OR 3.77; p=0.025) were all significantly higher with LDH levels &gt;600 IU/L. Conclusions: Maternal serum LDH levels were found to be significantly increased in pregnant women with severe preeclampsia compared to their normotensive counterparts, and elevated levels &gt;600 IU/L in the third trimester was associated with adverse perinatal outcomes
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