2,485 research outputs found

    Walking the Talk: Doing Science with Perimenopausal Women and their Health Care Providers

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    Perimenopausal high estrogen levels amplify the social stress of changing reproductive status in a culture that places value on women’s youth and beauty. As it was realized that progesterone physiologically counterbalances the effects of estrogen, it would be better to use progesterone, rather than estrogen for appropriate therapy of perimenopause. Based on this new knowledge was designed a three-arm study project comparing the recommended therapy, low dose OC (oral contraceptives) against progesterone therapy. In the pilot project cooperated Health Care Providers (HCP), by whose help was assembled eleven domains, which perimenopausal women find the most problematic. These HCP were also providing consultations for women with these problems, what gave to the women a good chance of self-analyses of their experience, and to HCP knowledge that the participation with their patients can bring something new into their practice

    Dissipative Transport of a Bose-Einstein Condensate

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    We investigate the effects of impurities, either correlated disorder or a single Gaussian defect, on the collective dipole motion of a Bose-Einstein condensate of 7^7Li in an optical trap. We find that this motion is damped at a rate dependent on the impurity strength, condensate center-of-mass velocity, and interatomic interactions. Damping in the Thomas-Fermi regime depends universally on the disordered potential strength scaled to the condensate chemical potential and the condensate velocity scaled to the peak speed of sound. The damping rate is comparatively small in the weakly interacting regime, and the damping in this case is accompanied by strong condensate fragmentation. \textit{In situ} and time-of-flight images of the atomic cloud provide evidence that this fragmentation is driven by dark soliton formation.Comment: 14 pages, 20 figure

    Experimental detection of entanglement via witness operators and local measurements

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    In this paper we address the problem of detection of entanglement using only few local measurements when some knowledge about the state is given. The idea is based on an optimized decomposition of witness operators into local operators. We discuss two possible ways of optimizing this local decomposition. We present several analytical results and estimates for optimized detection strategies for NPT states of 2x2 and NxM systems, entangled states in 3 qubit systems, and bound entangled states in 3x3 and 2x4 systems.Comment: 24 pages, 2 figures. Contribution to the proceedings of the International Conference on Quantum Information in Oviedo, Spain (July 13-18, 2002). Error in W_W1-witness Eq. (35) corrected as well as minor typos. Reference adde

    Strain Relaxation Mechanisms and Local Structural Changes in Si_{1-x}$Ge_{x} Alloys

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    In this work, we address issues pertinent to the understanding of the structural and electronic properties of Si_{1-x} Ge_{x}alloys, namely, (i) how does the lattice constant mismatch between bulk Si and bulk Ge manifests itself in the alloy system? and (ii) what are the relevant strain release mechanisms? To provide answers to these questions, we have carried out an in-depth study of the changes in the local geometric and electronic structures arising from the strain relaxation in Si_{1-x} Ge_{x} alloys using an ab initio molecular dynamics scheme. The optimized lattice constant, while exhibiting a general trend of linear dependence on the composition (Vegard's law), shows a negative deviation from Vegard's law in the vicinity of x=0.5. We delineate the mechanisms responsible for each one of the above features. We show that the radial-strain relaxation through bond stretching is responsible for the overall trend of linear dependence of the lattice constant on the composition. On the other hand, the negative deviation from Vegard's law is shown to arise from the angular-strain relaxation.Comment: 21 pages, 7 figure

    Source Level Attribution: DNA Profiling from the ABAcardÂź HemaTraceÂź Kit

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    ABAcardÂź HemaTraceÂź kits have been used for crime scene stains for confirmation of human blood for many years. However, when the stain is too small to allow for separate testing, confirmatory testing may be forgone to preference DNA analysis. This can lead to court challenges as to the biological source and therefore probative value of the DNA profile. This research aimed to develop a protocol for DNA analysis of a minute blood stain subsequent to HemaTraceÂź testing. Stains were collected and subjected to HemaTraceÂź testing. Swabs were then removed from the HemaTraceÂź buffer solution and processed. DNA yields and STR DNA profiles were analysed for both quantity and quality. Full profiles were reliably obtained from stains with diameters of 0.6 mm–0.7 mm, reflecting DNA concentrations between 0.0036 ng/ÎŒL and 0.007 ng/ÎŒL, varying according to substrate characteristics. However, stains below a diameter of 0.6 mm should proceed directly for DNA profiling. This protocol was also successfully performed on blood stains which had undergone UV irradiation, although use of the reporting peak height threshold (lower than the routine analytical threshold) was required to obtain useable profiles. We have been able to demonstrate a protocol which, with minor adjustments to crime scene procedures, allows for both the confirmation of the presence of human blood, together with the generation of useful DNA profiles.</jats:p

    Hydrochorous Seed Dispersal in Riparian Forests Altered by Urbanization

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    While riparian habitat alterations from urban stream syndrome are known to affect vegetation establishment and survival, the degree to which riparian seed delivery by hydrochory is affected by urbanization is unclear. We hypothesized that (1) there would be a reduction in the overall number of seeds deposited by streams as watershed urbanization increased; and (2) in the most urbanized watersheds, seeds deposited by water would be predominantly from species with traits favoring dispersal in general, including tall stature and high seed production, and favoring deposition by water in particular, including large seed size and the presence of a dispersal appendage. Nine riparian forests, selected using a stratified random approach, were studied along a gradient of watershed impervious surface area (1–41%) in the Portland, Oregon, USA , metropolitan region. Seeds deposited by water were collected using turf traps four times over a 15‐month period that spanned both wet and dry seasonal conditions. Along the urbanization gradient of increasing total impervious area, there was a significant decrease in the total number of seeds deposited by hydrochory (adjusted R 2 = 0.74; P \u3c 0.01). Deposition of seeds from shade‐tolerant and native taxa by water decreased as surrounding urbanization increased (adjusted R 2 = 0.57; P \u3c 0.05). Deposition of non‐native seeds increased as urban development within 500 m from the riparian area increased (adjusted R 2 = 0.79, P \u3c 0.01). The findings demonstrate that seed dispersal patterns in riparian areas are altered by urbanization. During higher rainfall seasons, flashy hydrology and stream bank scour appear to alter seed delivery in highly urban watersheds. While the urban stream syndrome contributes to altered dispersal, other urbanization pressures that affect source populations, such as vegetation removal, also limit seed delivery to riparian sites. Overall, our results suggest that urbanization can limit the regeneration processes that maintain vegetation communities in riparian forests

    Numerical study of one-dimensional and interacting Bose-Einstein condensates in a random potential

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    We present a detailed numerical study of the effect of a disordered potential on a confined one-dimensional Bose-Einstein condensate, in the framework of a mean-field description. For repulsive interactions, we consider the Thomas-Fermi and Gaussian limits and for attractive interactions the behavior of soliton solutions. We find that the disorder average spatial extension of the stationary density profile decreases with an increasing strength of the disordered potential both for repulsive and attractive interactions among bosons. In the Thomas Fermi limit, the suppression of transport is accompanied by a strong localization of the bosons around the state k=0 in momentum space. The time dependent density profiles differ considerably in the cases we have considered. For attractive Bose-Einstein condensates, a bright soliton exists with an overall unchanged shape, but a disorder dependent width. For weak disorder, the soliton moves on and for a stronger disorder, it bounces back and forth between high potential barriers.Comment: 13 pages, 13 figures, few typos correcte

    A DSEL for Studying and Explaining Causation

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    We present a domain-specific embedded language (DSEL) in Haskell that supports the philosophical study and practical explanation of causation. The language provides constructs for modeling situations comprised of events and functions for reliably determining the complex causal relationships that emerge between these events. It enables the creation of visual explanations of these causal relationships and a means to systematically generate alternative, related scenarios, along with corresponding outcomes and causes. The DSEL is based on neuron diagrams, a visual notation that is well established in practice and has been successfully employed for causation explanation and research. In addition to its immediate applicability by users of neuron diagrams, the DSEL is extensible, allowing causation experts to extend the notation to introduce special-purpose causation constructs. The DSEL also extends the notation of neuron diagrams to operate over non-boolean values, improving its expressiveness and offering new possibilities for causation research and its applications.Comment: In Proceedings DSL 2011, arXiv:1109.032
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