2,126 research outputs found

    Prevalence and associated features of depression in women with Rett Syndrome

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    Background Little is known about depression among women with Rett syndrome (RTT) despite recent advances in knowledge about RTT. In this study, we aimed to establish the prevalence of depression among women with RTT as identified by a screening telephone interview and to explore the clinical factors associated with this. Methods The study employed the cross-sectional analysis of data from telephone interviews with carers of 56 women with RTT, using validated questionnaires for assessing mental health problems, challenging behaviour and RTT severity. Results Scores on the mental health assessment reached the affective/neurotic threshold in eight cases (14.3%). No significant differences were found between those reaching the threshold and those who did not in terms of severity of RTT phenotype, health problems or social circumstances. There was a significant association between screening identified depression and higher lethargy and social withdrawal. Conclusions Screening identified depression was found among a sizeable minority of women with RTT. Further investigation is needed to establish a clinically validated prevalence of depression among this group and to identify behavioural features that would lead to prompt psychiatric assessment

    Project Columbiad: Reestablishment of human presence on the Moon

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    In response to the Report of the Advisory Committee on the future of the U.S. Space Program and a request from NASA's Exploration Office, the MIT Hunsaker Aerospace Corporation (HAC) conducted a feasibility study, known as Project Columbiad, on reestablishing human presence on the Moon before the year 2000. The mission criteria established were to transport a four person crew to the lunar surface at any latitude and back to Earth with a 14-28 day stay on the lunar surface. Safety followed by cost of the Columbiad Mission were the top level priorities of HAC. The resulting design has a precursor mission that emplaces the required surface payloads before the piloted mission arrives. Both the precursor and piloted missions require two National Launch System (NLS) launches. Both the precursor and piloted missions have an Earth orbit rendezvous (EOR) with a direct transit to the Moon post-EOR. The piloted mission returns to Earth via a direct transit. Included among the surface payloads preemplaced are a habitat, solar power plant (including fuel cells for the lunar night), lunar rover, and mecanisms used to cover the habitat with regolith (lunar soil) in order to protect the crew members from severe solar flare radiation

    Sustained productivity in recombinant Chinese Hamster Ovary (CHO) cell lines: proteome analysis of the molecular basis for a process-related phenotype

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    <p>Abstract</p> <p>Background</p> <p>The ability of mammalian cell lines to sustain cell specific productivity (Qp) over the full duration of bioprocess culture is a highly desirable phenotype, but the molecular basis for sustainable productivity has not been previously investigated in detail. In order to identify proteins that may be associated with a sustained productivity phenotype, we have conducted a proteomic profiling analysis of two matched pairs of monoclonal antibody-producing Chinese hamster ovary (CHO) cell lines that differ in their ability to sustain productivity over a 10 day fed-batch culture.</p> <p>Results</p> <p>Proteomic profiling of inherent differences between the two sets of comparators using 2D-DIGE (Difference Gel Electrophoresis) and LC-MS/MS resulted in the identification of 89 distinct differentially expressed proteins. Overlap comparisons between the two sets of cell line pairs identified 12 proteins (AKRIB8, ANXA1, ANXA4, EIF3I, G6PD, HSPA8, HSP90B1, HSPD1, NUDC, PGAM1, RUVBL1 and CNN3) that were differentially expressed in the same direction.</p> <p>Conclusion</p> <p>These proteins may have an important role in sustaining high productivity of recombinant protein over the duration of a fed-batch bioprocess culture. It is possible that many of these proteins could be useful for future approaches to successfully manipulate or engineer CHO cells in order to sustain productivity of recombinant protein.</p

    WFIRST coronagraph detector trap modeling results and improvements

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    The WFIRST coronagraph is being designed to detect and characterize mature exoplanets through the starlight reflected from their surfaces and atmospheres. The light incident on the detector from these distant exoplanets is estimated to be on the order of a few photons per pixel per hour. To measure such small signals, the project has baselined the CCD201 detector made by e2v, a low-noise and high-efficiency electron-multiplying charge-coupled device (EMCCD), and has instituted a rigorous test and modeling program to characterize the device prior to flight. An important consideration is detector performance degradation over the proposed mission lifetime due to radiation exposure in space. To quantify this estimated loss in performance, the project has built a detector trap model that takes into account detailed trap interactions at the sub-pixel level, including stochastic trap capture and release, and the deferment of charge into subsequent pixels during parallel and serial clocking of the pseudo-two-phase CCD201 device. This paper describes recent detector trap model improvements and modeling results

    Analysis of detector performance in a gigahertz clock rate quantum key distribution system

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    We present a detailed analysis of a gigahertz clock rate environmentally robust phase-encoded quantum key distribution (QKD) system utilizing several different single-photon detectors, including the first implementation of an experimental resonant cavity thin-junction silicon single-photon avalanche diode. The system operates at a wavelength of 850 nm using standard telecommunications optical fibre. A general-purpose theoretical model for the performance of QKD systems is presented with reference to these experimental results before predictions are made about realistic detector developments in this system. We discuss, with reference to the theoretical model, how detector operating parameters can be further optimized to maximize key exchange rates

    Non-perturbative dynamics of hot non-Abelian gauge fields: beyond leading log approximation

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    Many aspects of high-temperature gauge theories, such as the electroweak baryon number violation rate, color conductivity, and the hard gluon damping rate, have previously been understood only at leading logarithmic order (that is, neglecting effects suppressed only by an inverse logarithm of the gauge coupling). We discuss how to systematically go beyond leading logarithmic order in the analysis of physical quantities. Specifically, we extend to next-to-leading-log order (NLLO) the simple leading-log effective theory due to Bodeker that describes non-perturbative color physics in hot non-Abelian plasmas. A suitable scaling analysis is used to show that no new operators enter the effective theory at next-to-leading-log order. However, a NLLO calculation of the color conductivity is required, and we report the resulting value. Our NLLO result for the color conductivity can be trivially combined with previous numerical work by G. Moore to yield a NLLO result for the hot electroweak baryon number violation rate.Comment: 20 pages, 1 figur

    Chemical and Photometric Evolution of Extended Ultraviolet Disks: Optical Spectroscopy of M83 (NGC5236) and NGC4625

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    We present the results from the analysis of optical spectra of 31 Halpha-selected regions in the extended UV (XUV) disks of M83 (NGC5236) and NGC4625 recently discovered by GALEX. The spectra were obtained using IMACS at Las Campanas Observatory 6.5m Magellan I telescope and COSMIC at the Palomar 200-inch telescope, respectively for M83 and NGC4625. The line ratios measured indicate nebular oxygen abundances (derived from the R23 parameter) of the order of Zsun/5-Zsun/10. For most emission-line regions analyzed the line fluxes and ratios measured are best reproduced by models of photoionization by single stars with masses in the range 20-40 Msun and oxygen abundances comparable to those derived from the R23 parameter. We find indications for a relatively high N/O abundance ratio in the XUV disk of M83. Although the metallicities derived imply that these are not the first stars formed in the XUV disks, such a level of enrichment could be reached in young spiral disks only 1 Gyr after these first stars would have formed. The amount of gas in the XUV disks allow maintaining the current level of star formation for at least a few Gyr.Comment: 52 pages, 8 tables, 7 figures, accepted for publication in Ap
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