2,323 research outputs found

    Transparent materials processing system

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    A zero gravity processing furnace system was designed that will allow acquisition of photographic or other visual information while the sample is being processed. A low temperature (30 to 400 C) test model with a flat specimen heated by quartz-halide lamps was constructed. A high temperature (400 to 1000 C) test model heated by resistance heaters, utilizing a cylindrical specimen and optics, was also built. Each of the test models is discussed in detail. Recommendations are given

    A Caching Scheme to Accelerate Kinetic Monte Carlo Simulations of Catalytic Reactions

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    Kinetic Monte Carlo (KMC) simulations have been instrumental in advancing our fundamental understanding of heterogeneously catalyzed reactions, with particular emphasis on structure sensitivity, ensemble effects, and the interplay between adlayer structure and adsorbate-adsorbate lateral interactions in shaping the observed kinetics. Yet, the computational cost of KMC remains high, thereby motivating the development of acceleration schemes that would improve the simulation effciency. We present an exact such scheme, which implements a caching algorithm along with shared-memory parallelization to improve the computational performance of simulations incorporating long-range adsorbate-adsorbate lateral interactions. This scheme is based on caching information about the energetic interaction patterns associated with the products of each possible lattice process (adsorption, desorption, reaction etc). Thus, every time a reaction occurs ("ongoing reaction") it enables fast updates of the rate constants of "affected reactions", i.e. possible reactions in the region of influence of the "ongoing reaction". Benchmarks on KMC simulations of NOx oxidation/reduction, yield acceleration factors of up to 20× when comparing single-thread runs without caching to runs on 16 threads with caching, for simulations with a cluster expansion Hamiltonian that incorporates up to 8th nearest-neighbor interactions

    Surveyor batteries Final engineering report

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    Design and performance of Surveyor spacecraft silver-zinc main batter

    Charting self-esteem during marital dissolution.

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    ObjectiveThe purpose of this study was to chart changes in self-esteem before and after marital dissolution to identify the factors that shape individuals' self-esteem during this life transition.MethodWe analyzed 10 annual waves of self-esteem data from 291 divorcees from a nationally representative panel study of the Netherlands (N ~ 13,000). We charted the course of self-esteem before and after marital dissolution and tested a broad set of moderator variables that may shape individuals' self-esteem trajectories.ResultsThe average divorcee experienced significant decrease in self-esteem preceding marital dissolution and remained stable afterward. There were substantial individual differences in self-esteem trajectories, both before and after marital separation. Divorcees who experienced financial hardship, were affiliated with a church or religion, or scored low in Conscientiousness showed the most pronounced decrease in self-esteem during the years approaching marital dissolution.ConclusionThis study highlights the importance of assessing people multiple times before and after marital dissolution to dissect how people approach and respond to this life event. Results are consistent with perspectives that view divorce as an opportunity to abate the strains of an unhappy marriage

    CMakeCatchTemplate: A C++ template project

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    CMakeCatchTemplate (https://github.com/MattClarkson/CMakeCatchTemplate) is a project to provide a starting structure for C++ projects configured with CMake, that can be customised to work in a variety of scenarios, allowing developers to deploy new algorithms to users in a shorter timeframe. Main features include a SuperBuild to build optional dependencies; unit tests using Catch; support for CUDA, OpenMP and MPI; examples of command line and GUI applications; Doxygen integration; Continuous Integration templates and support for building/deploying Python modules

    The eyes have it: Infant gaze as an indicator of hunger and satiation

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    Infant gaze serves as a measure of attention to food cues in adults and children and may play a role in signalling infant hunger and satiation. Maternal responsiveness to infant satiation cues, including gaze, supports healthy appetite development and may reduce obesity risk. However, mothers often experience difficulty in interpreting feeding cues, and there have been few attempts to study cues systematically. This study aimed to develop a reliable coding scheme for categorising and tracking infant gaze behaviours during complementary feeding (CF). Twenty infants aged between six and eighteen months were filmed during typical meals on two occasions at home. The Infant Gaze at Mealtime (IGM) coding scheme was devised from the analysis of a sample of videos, a piloting and testing process, and the feeding cues and developmental psychology literature. Inter and intra-rater reliability tests of the scheme with 20% of the study videos revealed high levels of reliability. When applied to the full sample of 225 video clips, the IGM coding scheme revealed a significant decrease over time in the frequency of infants gazing at food and a significant increase in exploratory gaze behaviour within a meal. These changes were consistent across main and dessert courses, suggesting they may be indicative of changes in infant feeding state. The results suggest that infant gaze may offer a means of identifying infant hunger and satiation and, as an easily observed behaviour, an effective tool for mothers and professionals for promoting responsive feeding

    The effect of food type on the portion size effect in children aged 2-12 years: A systematic review and meta-analysis.

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    Visual cues such as plate size, amount of food served and packaging are known to influence the effects of portion size on food intake. Unit bias is a well characterised heuristic and helps to determine consumption norms. In an obesogenic environment where large portions are common place, the unit or segmentation bias may be overridden promoting overconsumption of both amorphous or unit foods. The aim of this review was to investigate the impact of offering unit or amorphous food on the portion size effect (PSE) in children aged 2–12 years. A systematic search for literature was conducted in Medline, PsycInfo and Web of Science in February 2018. A total of 1197 papers were retrieved following the searches. Twenty-one papers were included in the systematic review, of which 15 provided requisite statistical information for inclusion in a random effects meta-analysis. Increasing children's food portion size by 51–100% led to a significant increase in intake (SMD = 0.47, 95% CI: 0.39–0.55). There was no evidence to suggest that increases in consumption were related to food type (p = 0.33), child age (p = 0.47) or initial portion size served (p=0.14). Residual heterogeneity was not significant (p=0.24). The PSE was demonstrated in children aged 2–12 years when offered both unit and amorphous food items. The effect was not restricted by food type, child age or influenced by initial portion size served. Of the studies included in the meta-analysis between study heterogeneity was low suggesting minimal variation in treatment effects between studies, however, more research is required to understand the mechanisms of the PSE in preschool children. Future research should determine feasible methods to downsize portion sizes served to children

    How have smallholder farmers used digital extension tools? Developer and user voices from Sub-Saharan Africa, South Asia and Southeast Asia

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    Digital extension tools (DETs) include phone calls, WhatsApp groups and specialised smartphone applications used for agricultural knowledge brokering. We researched processes through which DETs have (and have not) been used by farmers and other extension actors in low- and middle-income countries. We interviewed 40 DET developers across 21 countries and 101 DET users in Bihar, India. We found DET use is commonly constrained by fifteen pitfalls (unawareness of DET, inaccessible device, inaccessible electricity, inaccessible mobile network, insensitive to digital illiteracy, insensitive to illiteracy, unfamiliar language, slow to access, hard to interpret, unengaging, insensitive to user's knowledge, insensitive to priorities, insensitive to socio-economic constraints, irrelevant to farm, distrust). These pitfalls partially explain why women, less educated and less wealthy farmers often use DETs less, as well as why user-driven DETs (e.g. phone calls and chat apps) are often used more than externally-driven DETs (e.g. specialised smartphone apps). Our second key finding was that users often made - not just found - DETs useful for themselves and others. This suggests the word ‘appropriation’ conceptualises DET use more accurately and helpfully than the word ‘adoption’. Our final key finding was that developers and users advocated almost ubiquitously for involving desired users in DET provision. We synthesise these findings in a one-page framework to help funders and developers facilitate more useable, useful and positively impactful DETs. Overall, we conclude developers increase DET use by recognizing users as fellow developers – either through collaborative design or by designing adaptable DETs that create room for user innovation

    The program implications of administrative relationships between local health departments and state and local government.

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    A typology of organizational arrangements between state and local public health agencies was used as a framework within which the organizational environment of the local health department was studied for its effects on progam development and implementation by local public health departments. Data collected in a national sample of local health officers were used in measuring the effect of four different patterns of administrative relationships on the selected characteristics of local health department programs. Important differences were observed among the four organizational types with regard to constraints on programs and program priorities, and health officers' perceptions of the primary functions of local health departments and sources of local health department funding. These findings were then used as a baseline from which to consider the possible impact of recent federal health budgetary proposals (specifically, block grants) both on existing patterns of intergovernmental relations and on the funding and operation of local health department programs. It was determined that the most likely general development arising from these proposed changes in federal budgetary policy is that the administrative control of state health agencies over those at local level is likely to be enhanced. Other likely developments include changes in the programs and priorities of local health departments related to reductions in overall funding levels for human services and forced competition for fewer dollars by an enlarged constituency

    MAGRITTE, a modern software library for 3D radiative transfer - II. Adaptive ray-tracing, mesh construction, and reduction

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    Radiative transfer is a notoriously difficult and computationally demanding problem. Yet, it is an indispensable ingredient in nearly all astrophysical and cosmological simulations. Choosing an appropriate discretization scheme is a crucial part of the simulation, since it not only determines the direct memory cost of the model but also largely determines the computational cost and the achievable accuracy. In this paper, we show how an appropriate choice of directional discretization scheme as well as spatial model mesh can help alleviate the computational cost, while largely retaining the accuracy. First, we discuss the adaptive ray-tracing scheme implemented in our 3D radiative transfer library MAGRITTE, that adapts the rays to the spatial mesh and uses a hierarchical directional discretization based on HEALPIX. Second, we demonstrate how the free and open-source software library GMSH can be used to generate high-quality meshes that can be easily tailored for MAGRITTE. In particular, we show how the local element size distribution of the mesh can be used to optimize the sampling of both analytically and numerically defined models. Furthermore, we show that when using the output of hydrodynamics simulations as input for a radiative transfer simulation, the number of elements in the input model can often be reduced by an order of magnitude, without significant loss of accuracy in the radiation field. We demonstrate this for two models based on a hierarchical octree mesh resulting from adaptive mesh refinement, as well as two models based on smoothed particle hydrodynamics data
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