761 research outputs found

    Prospects for a civil/military transport aircraft

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    The similarities and disparities between commercial and military payloads, design features, missions, and transport aircraft are enumerated. Two matrices of civil/military transport aircraft designs were evaluated to determine the most cost effective payloads for a projected commercial route structure and air freight market. The probability of this market developing and the prospects for alternate route structures and freight markets are evaluated along with the possible impact on the aircraft designs. Proposals to stimulate the market and increase the viability of the common aircraft concept are reviewed and the possible impact of higher cargo demand on prospects for common civil/military freighters is postulated. The implications of planned advanced technology developments on the aircraft performance and cost are also considered

    Combined Effects of Experimentally Elevated CORT and Predation Threat on Exploratory and Foraging Behavior of Desmognathus ochrophaeus

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    Amphibian responses to stress are generally mediated through glucocorticoids produced by the hypothalamic–pituitary–interrenal axis. Chronic elevation of glucocorticoids can result in delayed wound healing and growth, but less is known about its influence on behavioral responses to predators. We examined the effect of acute and chronic CORT elevation on exploratory and foraging behaviors of Allegheny Mountain Dusky Salamanders (Desmognathus ochrophaeus) exposed to kairomones from a predatory snake. We established ‘No CORT,\u27 ‘Acute CORT,\u27 and ‘Chronic CORT’ conditions during an 18-d preparation phase by varying salamander exposure to an exogenous source of CORT (0.51 mg/mL) delivered via cutaneous patch. During the trial phase, we conducted assays to evaluate exploratory and foraging behavior of salamanders from the different CORT groups when exposed to snake kairomones or control. Exploratory behavior was examined within a circular arena with a series of surmountable concentric barriers, and foraging behavior was observed within Petri dishes containing Drosophila prey. Salamanders experiencing both Chronic CORT and snake kairomones exhibited the least exploratory behavior, escaped the array with the lowest frequency, climbed the fewest barriers, and delayed their movement. However, foraging behavior (latency to strike at prey, number of strikes, number of prey captured) was not affected by exposure to CORT or snake kairomone. Our findings suggest that artificially elevated CORT can modify some behavioral responses to predator kairomones, but only when individuals experience multiple CORT applications in the period preceding the trials

    The Next Linear Collider machine protection system

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    The Next Linear Collider (NLC) electron and positron beams are capable of damaging the linac accelerating structure and beamline vacuum chambers during an individual aberrant accelerator pulse. Machine protection system (MPS) considerations, outlined in this paper, have an impact on the engineering and design of most machine components downstream of the damping ring injector complex. The MPS consists of two functional levels. The first is a system that provides a benign, single bunch, low intensity, high emittance beam that will be used for commissioning and at any time that the integrity or the settings of the downstream component are in doubt. This level also provides for the smooth transition back and forth between high power operation and the benign diagnostic pilot bunch operation. The pilot bunch parameters in the main linac are estimated on the basis of the expected stress in the accelerator structure copper. Beam tests have been done at the SLAC linac to examine the behaviour of the copper at the damage stress threshold. Typical pilot beam parameters (compared with nominal) are: 10 times reduced intensity, 10 times increased horizontal emittance and 1000 times increased vertical emittance, resulting in a reduction in charge density of 105. The second level is the primary protection against a single aberrant pulse. It’s goal is to reduce the possibility that a substantial transverse field changes the trajectory of the high power beam from one pulse to the next. All devices that could produce such a field are 1) monitored by a fast response network and 2) have deliberately slowed response times. A ‘maximum allowable interpulse difference ’ is evaluated for each such device as well as the beam trajectory monitors in each interpulse period.

    Employing machine learning to predict adverse acute post-surgical outcomes following elective ulnar collateral ligament reconstruction

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    Background: Ulnar collateral ligament reconstruction ameliorates valgus elbow instability in various patient populations, including overhead athletes, patients with acute UCL rupture following high energy trauma, and those with chronic, subclinical elbow laxity. This study aims to explore machine learning algorithms to identify risk factors in patients undergoing elective UCL reconstruction in the ambulatory setting to predict postoperative outcomes. Methods: RStudio was used to create a filtering code to identify adult patients who underwent elective UCL reconstruction from 2008 to 2018 in the American college of surgeons national surgical quality improvement program database. Patients were analyzed using six ML algorithms, which were trained to predict outcomes such as extended length of stay, non-home discharge, and adverse events based on various patient characteristics and surgical variables. Algorithmic performance was then assessed and top performing algorithms underwent further analysis to determine relative feature importance using a permutation feature importance method. Results: ML exhibited excellent performance in predicting LOS, with an average AUC of 0.953, similar to that of logistic regression. Regarding NHD, ML demonstrated a 60.8% increase in AUC compared to LR. In predicting AAE, ML achieved an average AUC that was 12.7% higher than LR. Conclusions: The highly predictive capability of ML indicates the possibility to represent a procedure-specific complementary tool for the preoperative risk stratification process. This study provides a comprehensive analysis of UCL reconstruction in the management and outcomes of any patient, regardless of age or activity level

    Minimal intervention delivered by 2-1-1 information and referral specialists promotes smoke-free homes among 2-1-1 callers: a Texas generalisation trial

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    Replication of intervention research is reported infrequently, limiting what we know about external validity and generalisability. The Smoke Free Homes Program, a minimal intervention, increased home smoking bans by United Way 2-1-1 callers in randomised controlled trials in Atlanta, Georgia and North Carolina

    Evidence of High Harmonics from Echo-Enabled Harmonic Generation for Seeding X-Ray Free Electron Lasers

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    Echo-enabled harmonic generation free electron lasers hold great promise for the generation of fully coherent radiation in x-ray wavelengths. Here we report the first evidence of high harmonics from the echo-enabled harmonic generation technique in the realistic scenario where the laser energy modulation is comparable to the beam slice energy spread. In this experiment, coherent radiation at the seventh harmonic of the second seed laser is generated when the energy modulation amplitude is about 2-3 times the slice energy spread. The experiment confirms the underlying physics of echo-enabled harmonic generation and may have a strong impact on emerging seeded x-ray free electron lasers that are capable of generating laserlike x rays which will advance many areas of science

    Toward optimal implementation of cancer prevention and control programs in public health: A study protocol on mis-implementation

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    Abstract Background Much of the cancer burden in the USA is preventable, through application of existing knowledge. State-level funders and public health practitioners are in ideal positions to affect programs and policies related to cancer control. Mis-implementation refers to ending effective programs and policies prematurely or continuing ineffective ones. Greater attention to mis-implementation should lead to use of effective interventions and more efficient expenditure of resources, which in the long term, will lead to more positive cancer outcomes. Methods This is a three-phase study that takes a comprehensive approach, leading to the elucidation of tactics for addressing mis-implementation. Phase 1: We assess the extent to which mis-implementation is occurring among state cancer control programs in public health. This initial phase will involve a survey of 800 practitioners representing all states. The programs represented will span the full continuum of cancer control, from primary prevention to survivorship. Phase 2: Using data from phase 1 to identify organizations in which mis-implementation is particularly high or low, the team will conduct eight comparative case studies to get a richer understanding of mis-implementation and to understand contextual differences. These case studies will highlight lessons learned about mis-implementation and identify hypothesized drivers. Phase 3: Agent-based modeling will be used to identify dynamic interactions between individual capacity, organizational capacity, use of evidence, funding, and external factors driving mis-implementation. The team will then translate and disseminate findings from phases 1 to 3 to practitioners and practice-related stakeholders to support the reduction of mis-implementation. Discussion This study is innovative and significant because it will (1) be the first to refine and further develop reliable and valid measures of mis-implementation of public health programs; (2) bring together a strong, transdisciplinary team with significant expertise in practice-based research; (3) use agent-based modeling to address cancer control implementation; and (4) use a participatory, evidence-based, stakeholder-driven approach that will identify key leverage points for addressing mis-implementation among state public health programs. This research is expected to provide replicable computational simulation models that can identify leverage points and public health system dynamics to reduce mis-implementation in cancer control and may be of interest to other health areas

    Long Term Protection after Immunization with P. berghei Sporozoites Correlates with Sustained IFNγ Responses of Hepatic CD8+ Memory T Cells

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    Protection against P. berghei malaria can successfully be induced in mice by immunization with both radiation attenuated sporozoites (RAS) arresting early during liver stage development, or sporozoites combined with chloroquine chemoprophylaxis (CPS), resulting in complete intra-hepatic parasite development before killing of blood-stages by chloroquine takes place. We assessed the longevity of protective cellular immune responses by RAS and CPS P. berghei immunization of C57BL/6j mice. Strong effector and memory (TEM) CD8+ T cell responses were induced predominantly in the liver of both RAS and CPS immunized mice while CD4+ T cells with memory phenotype remained at base line levels. Compared to unprotected naïve mice, we found high sporozoite-specific IFNγ ex vivo responses that associated with induced levels of in vivo CD8+ TEM cells in the liver but not spleen. Long term evaluation over a period of 9 months showed a decline of malaria-specific IFNγ responses in RAS and CPS mice that significantly correlated with loss of protection (r2 = 0.60, p<0.0001). The reducing IFNγ response by hepatic memory CD8+ T cells could be boosted by re-exposure to wild-type sporozoites. Our data show that sustainable protection against malaria associates with distinct intra-hepatic immune responses characterized by strong IFNγ producing CD8+ memory T cells
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