2,192 research outputs found

    Procedure for generating global atmospheric engine emissions data from future supersonic transport aircraft. The 1990 high speed civil transport studies

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    The input for global atmospheric chemistry models was generated for baseline High Speed Civil Transport (HSCT) configurations at Mach 1.6, 2.2, and 3.2. The input is supplied in the form of number of molecules of specific exhaust constituents injected into the atmosphere per year by latitude and by altitude (for 2-D codes). Seven exhaust constituents are currently supplied: NO, NO2, CO, CO2, H2O, SO2, and THC (Trace Hydrocarbons). An eighth input is also supplied, NO(x), the sum of NO and NO2. The number of molecules of a given constituent emitted per year is a function of the total fuel burned by a supersonic fleet and the emission index (EI) of the aircraft engine for the constituent in question. The EIs for an engine are supplied directly by the engine manufacturers. The annual fuel burn of a supersonic fleet is calculated from aircraft performance and economic criteria, both of which are strongly dependent on basic design parameters such as speed and range. The altitude and latitude distribution of the emission is determined based on 10 Intern. Air Transport Assoc. (IATA) regions chosen to define the worldwide route structure for future HSCT operations and the mission flight profiles

    Impact of Generalist Physician Initiatives on Residency Selection

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    Objective:To compare the residency selection choices of students who experienced courses resulting from generalist physician initiatives to choices made by students prior to the implementation of those courses and to describe the characteristics of students selecting primary care residencies. Background:In the fall of 1994 a first year Community Continuity Experience course was initiated and in the summer of 1995 a third year Multidisciplinary Ambulatory Clerkship was begun at the University of Texas Medical Branch in Galveston. These courses were inserted into the curriculum to enhance and promote primary care education. Design/Methods:We examined the residency selections of cohorts of graduating medical students before (1992-1996) and after (1997-1999) the implementation of the primary care courses. Survey information on career preferences at matriculation and in the fourth year of medical school were available for students graduating after the programs began. We compared the career preferences and characteristics of those students who selected a primary care residency to those who did not. Results:Prior to the implementation of the programs, 45%(425/950) of students graduating selected primary care residencies compared to 45% (210/465) of students participating in the programs (p=0.88). At matriculation, 45% of students had listed a primary care discipline as their first career choice. Among the students who had indicated this degree of primary care interest 61% ended up matching in a primary care discipline. At year 4, 31% of students indicated a primary care discipline as their first career choice and 92% of these students matched to a primary care residency. By univariate analysis, minority students (53%) were more likely to select a primary care residency than non-minority students (40%); students in the two lowest grade point average quartiles (55% and 50%) selected primary care residencies compared to 37% and 38% of students in the top 2 quartiles; and students who stated that income potential had little or no impact on their choice were more likely to select a primary care residency (48%) than those who said income potential was important (37%). Conclusions:We observed no significant trend towards higher proportions of graduating students selecting primary care discipline residencies as a result of implementing courses that emphasized primary care. Those students expressing an interest in a primary care discipline at their entrance into medical school were more likely to select a primary care residency. A more significant impact on graduating students interested in primary care may be made through the medical student selection process than by altering the curriculum

    Improving Root Health and Yield of Dry Beans in the Nebraska Panhandle with a New Technique for Reducing Soil Compaction

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    A field study conducted during the 2001 and 2002 growing seasons investigated the integration of fungicide applications and tillage methods for reducing root health problems in dry bean (Phaseolus vulgaris) plants by alleviating soil compaction and its potential exacerbation of root disease. Several cultural practices were combined with applications of the strobilurin fungicide azoxystrobin. Soil compaction was created artificially throughout the entire plot area. Six treatments, consisting of four tillage treatments and two combinations of tillage or applications of azoxystrobin, were tested to alleviate the compaction and enhance root health. Tillage treatments included a compacted control with no additional tillage, formation of beds approximately 10 cm above soil surface, zone tillage with an implement using in-row shanks, and both zone tillage and bedding combined. Fungicide treatments utilized the combination of both zone tillage and bedding with fungicide applications, and a fungicide treatment singly. Effects of compaction on plant vigor and disease development and severity were evaluated 67 and 83 days after planting in 2001 and 2002, respectively, by a visual estimation of plot vigor and by destructively sampling and making root and hypocotyl disease ratings on dry bean plants from nonharvest rows. Soil resistance and moisture were measured in plots 80 and 104 days after planting in 2001 and 2002, respectively, to estimate degree of compaction. In both years, Fusarium root rot, caused by Fusarium solani f. sp. phaseoli, was determined to be the main root disease impacting plant health in studies. All measured variables (root disease index, plant vigor ratings, total seed yield, seed size, and soil resistance) were significantly improved by any treatment that included zone tillage prior to planting. No added advantages were observed for decreasing disease or improving root health and plant performance with the use of azoxystrobin or by planting on raised beds. This is the first study to evaluate zone tillage as a method of reducing plant stress and root disease in dry bean plants

    The design of mixed-use virtual auditory displays: Recent findings with a dual-task paradigm

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    Presented at the 10th International Conference on Auditory Display (ICAD2004)In the third of an ongoing series of exploratory sound information display studies, we augmented a dual task with a mixed-use auditory display designed to provide relevant alert information for each task. The tasks entail a continuous tracking activity and a series of intermittent classification decisions that, in the present study, were presented on separate monitors that were roughly 90\,^{\circ} apart. Using a 2-by-3 design that manipulated both the use of sound in each task and where sounds for the decision task were positioned, the following principal questions were addressed: Can tracking performance be improved with a varying auditory alert tied to error? To what degree do listeners use virtual auditory deixis as a cue for improving decision reaction times? Can a previous finding involving participants' use of sound offsets (cessations) be repeated? And, last, are there performance consequences when auditory displays for separate tasks are combined? Respectively, we found that: Tracking performance as measured by RMS error was not improved and was apparently negatively affected by the use of our auditory design. Listener's use of even limited virtual auditory deixis is robust, but it is probably also sensitive to the degree it is coincident with the location of corresponding visual stimuli in the task environment. On the basis of manually collected head movement data, listeners do make opportunistic use of sound offsets. And, finally, a significant interaction, as measured by average participant reaction time, was observed between the auditory display used for one task and the manipulation of the degree of auditory deixis encoded in the auditory display used for the other task in our paradigm

    Bathymetric Mapping and Sonar Imaging of Tufa at Green Lakes: Fayetteville, New York

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    The Fayetteville Green Lakes State Park, located in Fayetteville, New York, consists of two deep (48 m+), meromictic (non-mixing) lakes with unique limnological, bacterial, and chemical characteristics. These lakes, named Round Lake and its larger companion Green Lake, have been extensively studied for nearly 200 years because of their unique character. The lake water contains two distinct layers, the oxygen-rich mixolimnion and the anoxic monimolimnion divided by the chemocline (a chemical compositional boundary). Tufa deposits exist along the shorelines of both lakes at various depths and are a product of groundwater output into the lakes, as well as the lakes’ unique water chemistry and microbial communities. Here, we use sonar imaging techniques to produce updated bathymetric maps of Green and Round Lake, and provide the first detailed characterization of the near-shore environment using side-scanning sonar imagery to determine the locations and morphologies of tufa deposits. We also document shoreline debris specifically large tree trunks and branches which have fallen into the lake over time and are frequently encrusted. We identified fourteen locations of tufa ranging from large formations (10s of meters long) to small tufa heads (~1 m) in Green Lake. Our updated bathymetry and documentation of tufa locations and geometry expand on an extensive history of prior work, will aid future investigators by revealing lesser-known tufa localities, and will assist the Fayetteville Green Lakes State Park with monitoring and conservation efforts for this ecologically unique area

    A multiple imputation strategy for sequential multiple assignment randomized trials

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    Sequential multiple assignment randomized trials (SMARTs) are increasingly being used to inform clinical and intervention science. In a SMART, each patient is repeatedly randomized over time. Each randomization occurs at a critical decision point in the treatment course. These critical decision points often correspond to milestones in the disease process or other changes in a patient's health status. Thus, the timing and number of randomizations may vary across patients and depend on evolving patient‐specific information. This presents unique challenges when analyzing data from a SMART in the presence of missing data. This paper presents the first comprehensive discussion of missing data issues typical of SMART studies: we describe five specific challenges and propose a flexible imputation strategy to facilitate valid statistical estimation and inference using incomplete data from a SMART. To illustrate these contributions, we consider data from the Clinical Antipsychotic Trial of Intervention and Effectiveness, one of the most well‐known SMARTs to date. Copyright © 2014 John Wiley & Sons, Ltd.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108622/1/sim6223-sup-0001-SupInfo.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/108622/2/sim6223.pd

    Compatibility between the endoparasitoid Hyposoter didymator and the entomopathogenic fungus Metarhizium brunneum: A laboratory simulation for the simultaneous use to control Spodoptera littoralis

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    BACKGROUND The cotton leafworm, Spodoptera littoralis, is one of the most destructive pests in the Mediterranean basin, being predominantly controlled using synthetic chemical pesticides. Strain EAMa 01/58‐Su of the fungus Metarhizium brunneum and the parasitoid Hyposoter didymator are promising biological control agents for this pest. In this study, we assessed the compatibility between these two agents to control S. littoralis under joint attack scenarios. RESULTS Firstly, the direct and indirect effects of the fungus towards parasitoid adults were studied. The fungus significantly decreased life expectancy of the parasitoid (mortality=62.5%; mean lethal concentration=1.85×106 conidia ml‐1; average survival time=92.2h) when applied at high concentrations (108 conidia ml‐1), whereas it did not affect the reproductive potential of the parasitoid females during the three days after treatment. Secondly, the combinations between the two agents to control S. littoralis under different simultaneous use scenarios (inoculation of S. littoralis larvae with the fungus before being exposed to parasitoid females and vice versa) were investigated, with additive effect in all cases. A significant effect on fitness (preimaginal development time and reproductive potential) of the F1 parasitoid generation were detected. Moreover, parasitization significantly reduced the total haemocytes in S. littoralis haemolymph compared with the control, promoting fungal infection. Finally, parasitoids showed a significant preference for non‐inoculated S. littoralis larvae. CONCLUSIONS We demonstrated compatibility (additive effect) between fungus and parasitoid under different joint attack scenarios to control S. littoralis in laboratory conditions. However, this will be supported by our ongoing greenhouse and field studies

    Supplemental Appendix for "The Enrollment of Racially Minoritized Students in Law School: Factors Predicting Within-School Changes Over Time"

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    Given the substantial lack of racial diversity within the U.S. legal profession, it is important to understand how to improve the representation of racially minoritized students at law schools. This study uses panel data from the 2010s to consider several types of factors that may shape the number and percentage of incoming law school students from several racially minoritized groups: finances (regarding financial aid and cost of attendance), demographic representation (of current students, faculty, and community members), and rankings (from U.S. News). The results of fixed effects analyses revealed that increases in the representation of Latinx and Asian students as well as Faculty of Color predict subsequent decreases in the percentage of incoming racially minoritized students, which suggests that law schools' efforts to recruit racially minoritized students may depend on recent changes in student and faculty representation. Moreover, increases in the ingroup racial representation within the state (in which the law school is primarily housed) and U.S. News rankings are both associated with greater subsequent numbers of incoming Black and Latinx law students; the provision of conditional scholarships and the combined total of tuition and fees are also significant predictors. These findings have salient implications for policy and practice.Table S1. Descriptive Statistics for All Variables Table S2. Unstandardized Coefficients for Random Effects Analyses Predicting Law School Student Enrollment Percentages among All Students Table S3. Unstandardized Coefficients for Random Effects Analyses Predicting Student Enrollment Count
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