5,793 research outputs found

    Coping Strategies in Middle Childhood: The Role of Parental Modeling

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    Developing effective coping strategies during middle childhood may place individuals on more adaptive developmental trajectories for coping throughout adulthood, yet little is known about how children develop these strategies. This project aims to understand the ways in which parents act as models for their children as they develop coping strategies. Participants included 65 children, aged 8-10 (M = 9.51, SD = .81; 29 females; 93.8% White), and at least one parent (65 mothers; 35 fathers). Hierarchical multiple regression analyses were conducted to examine cross-sectional and longitudinal associations between parents’ responses to stress and children’s responses to stress. Cross-sectionally, mothers’ engagement coping was associated with more engagement coping and less involuntary engagement coping in children. Longitudinally, mothers’ disengagement coping predicted higher levels of engagement coping and fewer involuntary responses to stress in children after a six-month follow-up. Results suggest that if adaptive coping strategies are established in parents, it has the potential to benefit children’s coping as well, thus supporting a family-wide approach in skill-building interventions for children

    In-Space technology experiments program. A high efficiency thermal interface (using condensation heat transfer) between a 2-phase fluid loop and heatpipe radiator: Experiment definition phase

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    Space Station elements and advanced military spacecraft will require rejection of tens of kilowatts of waste heat. Large space radiators and two-phase heat transport loops will be required. To minimize radiator size and weight, it is critical to minimize the temperature drop between the heat source and sink. Under an Air Force contract, a unique, high-performance heat exchanger is developed for coupling the radiator to the transport loop. Since fluid flow through the heat exchanger is driven by capillary forces which are easily dominated by gravity forces in ground testing, it is necessary to perform microgravity thermal testing to verify the design. This contract consists of an experiment definition phase leading to a preliminary design and cost estimate for a shuttle-based flight experiment of this heat exchanger design. This program will utilize modified hardware from a ground test program for the heat exchanger

    Expanding the scope of powerful electrochemical methods by exploiting nanoconfined cascade catalysis

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    The Electrochemical Leaf (e-Leaf) extends powerful electrochemical methods, historically only applicable to a relatively small group of “electroactive” enzymes (i.e., enzymes that can directly exchange electrons with an electrode), to non-electroactive enzymes. The technology works by trapping enzymes inside a nanoporous electrode and linking the reaction(s) catalyzed by the enzyme(s) of interest to an NADP(H)-recycling enzyme, ferredoxin NADP+-reductase (FNR), which is controlled electrochemically; the outcome is that the catalytic activity of the overall enzyme cascade is simultaneously energized (via the applied electrode potential) and monitored (as electrical current) in real time. Much of this work focuses on using the e-Leaf to study wildtype isocitrate dehydrogenase 1 (IDH1) and several cancer-associated IDH1 variants. Exploiting the unique advantages of the e-Leaf for investigating slow, tight-binding inhibitors, a method and analytical framework are developed to investigate the kinetics of inhibition of a cancer-associated IDH1 variant by multiple FDA-approved drugs. Implementation of this method leads to a proposed general kinetic mechanism for allosteric IDH inhibition. Notably, the inhibition kinetics are very slow, and the data show that inhibitors can bind in both inhibitory and non-inhibitory modes. Separately, the ability of IDH1 to copurify from cells with bound NADP(H) is used to “shuttle” NADP(H) into a nanoporous electrode to create a nanoconfined NADP(H)-dependent system which can be run without any external NADP(H), i.e., only the NADP(H) that copurified bound to IDH1 is required for cascade catalysis. The system is extraordinarily stable and is able to carry out bulk electrolysis over a five-day period with an NADP(H) total turnover number of ~160,000. The presence of a finite quantity of NADP(H) in the electrode (without any NADP(H) in the bulk solution) is used to quantify concentrations of NADP(H) and IDH1 in the electrode nanopores. Together with values obtained for FNR, total nonconfined enzyme concentrations ([FNR] + [IDH1]) are shown to be ~2 mM, approaching the physical limit. At such concentrations, the average center-to-center distance between enzymes is just 9.4 nm; this leads to a “cluster channeling” effect that increases the overall enzyme cascade efficiency by preventing cascade intermediates from escaping the nanoporous electrode. Together, this work demonstrates the power of electrochemical methods for enzyme mechanistic studies and quantifies the benefits of nanoconfinement for increasing the efficiency of cascade catalysis

    Space-efficient detection of unusual words

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    Detecting all the strings that occur in a text more frequently or less frequently than expected according to an IID or a Markov model is a basic problem in string mining, yet current algorithms are based on data structures that are either space-inefficient or incur large slowdowns, and current implementations cannot scale to genomes or metagenomes in practice. In this paper we engineer an algorithm based on the suffix tree of a string to use just a small data structure built on the Burrows-Wheeler transform, and a stack of O(σ2log⁥2n)O(\sigma^2\log^2 n) bits, where nn is the length of the string and σ\sigma is the size of the alphabet. The size of the stack is o(n)o(n) except for very large values of σ\sigma. We further improve the algorithm by removing its time dependency on σ\sigma, by reporting only a subset of the maximal repeats and of the minimal rare words of the string, and by detecting and scoring candidate under-represented strings that do not occur\textit{do not occur} in the string. Our algorithms are practical and work directly on the BWT, thus they can be immediately applied to a number of existing datasets that are available in this form, returning this string mining problem to a manageable scale.Comment: arXiv admin note: text overlap with arXiv:1502.0637

    The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1

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    The mid-Miocene climatic optimum (MMCO) is an intriguing climatic period due to its above-modern temperatures in mid-to-high latitudes in the presence of close-to-modern CO<sub>2</sub> concentrations. We use the recently released Community Earth System Model (CESM1.0) with a slab ocean to simulate this warm period, incorporating recent Miocene CO<sub>2</sub> reconstructions of 400 ppm (parts per million). We simulate a global mean annual temperature (MAT) of 18 °C, ~4 °C above the preindustrial value, but 4 °C colder than the global Miocene MAT we calculate from climate proxies. Sensitivity tests reveal that the inclusion of a reduced Antarctic ice sheet, an equatorial Pacific temperature gradient characteristic of a permanent El Niño, increased CO<sub>2</sub> to 560 ppm, and variations in obliquity only marginally improve model–data agreement. All MMCO simulations have an Equator to pole temperature gradient that is at least ~10 °C larger than that reconstructed from proxies. The MMCO simulation most comparable to the proxy records requires a CO<sub>2</sub> concentration of 800 ppm. Our results illustrate that MMCO warmth is not reproducible using the CESM1.0 forced with CO<sub>2</sub> concentrations reconstructed for the Miocene or including various proposed Earth system feedbacks; the remaining discrepancy in the MAT is comparable to that introduced by a CO<sub>2</sub> doubling. The model's tendency to underestimate proxy derived global MAT and overestimate the Equator to pole temperature gradient suggests a major climate problem in the MMCO akin to those in the Eocene. Our results imply that this latest model, as with previous generations of climate models, is either not sensitive enough or additional forcings remain missing that explain half of the anomalous warmth and pronounced polar amplification of the MMCO

    Marines vs. Contractors: an analysis of a supply outsourcing initiative and its impact on cost and efficiency

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    Since 2001, the Marine Corps has outsourced the management of all individual issue combat gear. This contracted outsourcing, called the Consolidated Issue Facility (CIF) and then the Individual Issue Facility (IIF) under the direction of local Marine Expeditionary Force Headquarters (MEF HQ) and Marine Corps Logistics Command (LOGCOM), are responsible for the distribution, management, and collection of every Marine's individual combat issue of gear; a task previously accomplished by each unit's individual organic supply section. By removing this burden on the supply sections, the Marine Corps was theoretically able to free-up Marines to fill billets in warfighting roles. The Marine Corps has touted the ability to save money and create efficiencies that did not exist previously with organic Marine Corps led supply operations. The Marine Corps is looking to increase the amount of assets managed by an outside vendor, by outsourcing management of unit assets such as Soft Walled Shelters and Camouflage netting to a Unit Issue Facility (UIF) using the same model as the CIF/IIF. This paper will explore if the CIF/IIF program saved the Marine Corps money from 2001 thru 2010, allowed for transfer of personnel to other roles, and if the program is an effective model for future outsourcing endeavors.http://archive.org/details/marinesvscontrac1094510592US Marine Corps (USMC) author

    Conformations and membrane-driven self-organization of rodlike fd virus particles on freestanding lipid membranes.

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    Membrane-mediated interactions and aggregation of colloidal particles adsorbed to responsive elastic membranes are challenging problems relevant for understanding the microscopic organization and dynamics of biological membranes. We experimentally study the behavior of rodlike semiflexible fd virus particles electrostatically adsorbed to freestanding cationic lipid membranes and find that their behavior can be controlled by tuning the membrane charge and ionic strength of the surrounding medium. Three distinct interaction regimes of rodlike virus particles with responsive elastic membranes can be observed. (i) A weakly charged freestanding cationic lipid bilayer in a low ionic strength medium represents a gentle quasi-2D substrate preserving the integrity, structure, and mechanical properties of the membrane-bound semiflexible fd virus, which under these conditions is characterized by a monomer length of 884 ± 4 nm and a persistence length of 2.5 ± 0.2 mum, in perfect agreement with its properties in bulk media. (ii) An increase in the membrane charge leads to the membrane-driven collapse of fd virus particles on freestanding lipid bilayers and lipid nanotubes into compact globules. (iii) When the membrane charge is low, and the mutual electrostatic repulsion of membrane-bound virus particles is screened to a considerable degree, membrane-driven self-organization of membrane-bound fd virus particles into long linear tip-to-tip aggregates showing dynamic self-assembly/disassembly and quasi-semiflexible behavior takes place. These observations are in perfect agreement with the results of recent theoretical and simulation studies predicting that membrane-mediated interactions can control the behavior of colloidal particles adsorbed on responsive elastic membranes
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