12,976 research outputs found
Incidence and risk factors for placenta accreta/increta/percreta in the UK: a national case-control study.
Placenta accreta/increta/percreta is associated with major pregnancy complications and is thought to be becoming more common. The aims of this study were to estimate the incidence of placenta accreta/increta/percreta in the UK and to investigate and quantify the associated risk factors
The Conformal Sector of F-theory GUTs
D3-brane probes of exceptional Yukawa points in F-theory GUTs are natural
hidden sectors for particle phenomenology. We find that coupling the probe to
the MSSM yields a new class of N = 1 conformal fixed points with computable
infrared R-charges. Quite surprisingly, we find that the MSSM only weakly mixes
with the strongly coupled sector in the sense that the MSSM fields pick up
small exactly computable anomalous dimensions. Additionally, we find that
although the states of the probe sector transform as complete GUT multiplets,
their coupling to Standard Model fields leads to a calculable threshold
correction to the running of the visible sector gauge couplings which improves
precision unification. We also briefly consider scenarios in which SUSY is
broken in the hidden sector. This leads to a gauge mediated spectrum for the
gauginos and first two superpartner generations, with additional contributions
to the third generation superpartners and Higgs sector.Comment: v2: 51 pages, 2 figures, remark added, typos correcte
Methanol poisoning and long term sequelae – a six years follow-up after a large methanol outbreak
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Fossils reveal the complex evolutionary history of the mammalian regionalized spine.
A unique characteristic of mammals is a vertebral column with anatomically distinct regions, but when and how this trait evolved remains unknown. We reconstructed vertebral regions and their morphological disparity in the extinct forerunners of mammals, the nonmammalian synapsids, to elucidate the evolution of mammalian axial differentiation. Mapping patterns of regionalization and disparity (heterogeneity) across amniotes reveals that both traits increased during synapsid evolution. However, the onset of regionalization predates increased heterogeneity. On the basis of inferred homology patterns, we propose a "pectoral-first" hypothesis for region acquisition, whereby evolutionary shifts in forelimb function in nonmammalian therapsids drove increasing vertebral modularity prior to differentiation of the vertebral column for specialized functions in mammals
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Pattern-distortion technique: using liquid-lens magnification to extract volumes of individual droplets or bubbles within evaporating two-dimensional arrays
We present an experimental "Pattern Distortion" technique which connects the shape of a liquid lens to its magnification. We demonstrate how to optimise the technique for arbitrary droplet sizes and optical configurations, and demonstrate its widespread utility in three distinct situations. Firstly we consider multiple sessile droplets. Although ubiquitous in nature, understanding of their complex interactions is limited, partly due to experimental limitations in determining individual droplet volumes for arbitrary configurations. We use the Pattern Distortion technique to overcome these limitations and find excellent agreement between our experimental data and three recent theoretical models. Secondly, we show how our technique can be used to inform the design of liquid lenses and thirdly we extend the method to composite droplets systems, using it to extract the size of an air bubble trapped inside a liquid droplet
Boolean network model predicts cell cycle sequence of fission yeast
A Boolean network model of the cell-cycle regulatory network of fission yeast
(Schizosaccharomyces Pombe) is constructed solely on the basis of the known
biochemical interaction topology. Simulating the model in the computer,
faithfully reproduces the known sequence of regulatory activity patterns along
the cell cycle of the living cell. Contrary to existing differential equation
models, no parameters enter the model except the structure of the regulatory
circuitry. The dynamical properties of the model indicate that the biological
dynamical sequence is robustly implemented in the regulatory network, with the
biological stationary state G1 corresponding to the dominant attractor in state
space, and with the biological regulatory sequence being a strongly attractive
trajectory. Comparing the fission yeast cell-cycle model to a similar model of
the corresponding network in S. cerevisiae, a remarkable difference in
circuitry, as well as dynamics is observed. While the latter operates in a
strongly damped mode, driven by external excitation, the S. pombe network
represents an auto-excited system with external damping.Comment: 10 pages, 3 figure
Methods for identifying surgical wound infection after discharge from hospital: a systematic review.
Background: Wound infections are a common complication of surgery that add significantly to the morbidity of patients and costs of treatment. The global trend towards reducing length of hospital stay post-surgery and the increase in day case surgery means that surgical site infections (SSI) will increasingly occur after hospital discharge. Surveillance of SSIs is important because rates of SSI are viewed as a measure of hospital performance, however accurate detection of SSIs post-hospital discharge is not straightforward. Methods: We conducted a systematic review of methods of post discharge surveillance for surgical wound infection and undertook a national audit of methods of post-discharge surveillance for surgical site infection currently used within United Kingdom NHS Trusts. Results: Seven reports of six comparative studies which examined the validity of post-discharge surveillance methods were located; these involved different comparisons and some had methodological limitations, making it difficult to identify an optimal method. Several studies evaluated automated screening of electronic records and found this to be a useful strategy for the identification of SSIs that occurred post discharge. The audit identified a wide range of relevant post-discharge surveillance programmes in England, Scotland and Wales and Northern Ireland; however, these programmes used varying approaches for which there is little supporting evidence of validity and/or reliability. Conclusion: In order to establish robust methods of surveillance for those surgical site infections that occur post discharge, there is a need to develop a method of case ascertainment that is valid and reliable post discharge. Existing research has not identified a valid and reliable method. A standardised definition of wound infection ( e. g. that of the Centres for Disease Control) should be used as a basis for developing a feasible, valid and reliable approach to defining post discharge SSI. At a local level, the method used to ascertain post discharge SSI will depend upon the purpose of the surveillance, the nature of available routine data and the resources available
Prognostic potential of body composition indices in detecting risk of musculoskeletal injury in army officer cadet profiles.
OBJECTIVES: High values in most of the body composition indices have been related to musculoskeletal injuries, but limited data exists on the accuracy of these diagnoses when detecting musculoskeletal injuries in military populations. METHODS: The suitability of body fat percentage, body mass index, fat mass index and fat free mass index to identify injury risk was examined in a group of army officer recruits. All body composition diagnoses were measured in 268 male army officer recruits prior to the commencement of basic combat training. Musculoskeletal injury was identified using codes from the International Classification of Diseases. The area under the curve, in the receiver operating characteristic curve, was used to quantify the overall ability to discriminate between those who were injured and those who were not. RESULTS: The statistics indicated that all indices, apart from body mass index, had a significant possibility to detect musculoskeletal injury potential (p 22, for fat mass index >6.5 and for fat free mass index <16.5. CONCLUSION: Body mass index values can not similarly detect the possibility of occurrence of musculoskeletal injuries in army officer recruits, just as other body composition diagnoses related to fat mass or/and free fat mass. However, the cut off-points related to the overall diagnostic performance of each body composition index should be used with caution and in accordance with the aims of each experimental setting
Alpha-band rhythms in visual task performance: phase-locking by rhythmic sensory stimulation
Oscillations are an important aspect of neuronal activity. Interestingly, oscillatory patterns are also observed in behaviour, such as in visual performance measures after the presentation of a brief sensory event in the visual or another modality. These oscillations in visual performance cycle at the typical frequencies of brain rhythms, suggesting that perception may be closely linked to brain oscillations. We here investigated this link for a prominent rhythm of the visual system (the alpha-rhythm, 8-12 Hz) by applying rhythmic visual stimulation at alpha-frequency (10.6 Hz), known to lead to a resonance response in visual areas, and testing its effects on subsequent visual target discrimination. Our data show that rhythmic visual stimulation at 10.6 Hz: 1) has specific behavioral consequences, relative to stimulation at control frequencies (3.9 Hz, 7.1 Hz, 14.2 Hz), and 2) leads to alpha-band oscillations in visual performance measures, that 3) correlate in precise frequency across individuals with resting alpha-rhythms recorded over parieto-occipital areas. The most parsimonious explanation for these three findings is entrainment (phase-locking) of ongoing perceptually relevant alpha-band brain oscillations by rhythmic sensory events. These findings are in line with occipital alpha-oscillations underlying periodicity in visual performance, and suggest that rhythmic stimulation at frequencies of intrinsic brain-rhythms can be used to reveal influences of these rhythms on task performance to study their functional roles
Education in Time: Cohort Differences in Educational Attainment in African-American Twins
OBJECTIVES:Educational opportunities for African-Americans expanded throughout the 20(th) century. Twin pairs are an informative population in which to examine changes in educational attainment because each twin has the same parents and childhood socioeconomic status. We hypothesized that correlation in educational attainment of older twin pairs would be higher compared to younger twin pairs reflecting changes in educational access over time and potentially reflecting a "ceiling effect" associated with Jim Crow laws and discrimination. METHODOLOGY AND PRINCIPAL FINDINGS:We used data from 211 same-sex twin pairs (98 identical, 113 fraternal) in the Carolina African-American Twin Study of Aging who were identified through birth records. Participants completed an in-person interview. The twins were predominantly female (61%), with a mean age of 50 years (SD = 0.5). We found that older age groups had a stronger intra-twin correlation of attained educational level. Further analysis across strata revealed a trend across zygosity, with identical twins demonstrating more similar educational attainment levels than did their fraternal twin counterparts, suggesting a genetic influence. DISCUSSION:These findings suggest that as educational opportunities broadened in the 20th century, African-Americans gained access to educational opportunities that better matched their individual abilities
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