6,689 research outputs found

    Sorghum aphid pest management (1985)

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    Revised 4/85/10M, New 4/92/5M

    Impact hazard protection efficiency by a small kinetic impactor

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    In this paper the ability of a small kinetic impactor spacecraft to mitigate an Earth-threatening asteroid is assessed by means of a novel measure of efficiency. This measure estimates the probability of a space system to deflect a single randomly-generated Earth-impacting object to a safe distance from the Earth. This represents a measure of efficiency that is not biased by the orbital parameters of a test-case object. A vast number of virtual Earth-impacting scenarios are investigated by homogenously distributing in orbital space a grid of 17,518 Earth impacting trajectories. The relative frequency of each trajectory is estimated by means Opik’s theory and Bottke’s near Earth objects model. A design of the entire mitigation mission is performed and the largest deflected asteroid computed for each impacting trajectory. The minimum detectable asteroid can also be estimated by an asteroid survey model. The results show that current technology would likely suffice against discovered airburst and local damage threats, whereas larger space systems would be necessary to reliably tackle impact hazard from larger threats. For example, it is shown that only 1,000 kg kinetic impactor would suffice to mitigate the impact threat of 27.1% of objects posing similar threat than that posed by Apophis

    STATUS OF COMPOUND DRC-1339 REGISTRATIONS

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    Compound DRC-1339 is a restricted-use, slow-acting avicide that is registered to control a number of avian pests. It is unique because of its selective high toxicity to most pest birds, low-to-moderate toxicity to most mammals and predatory birds, and lack of known secondary hazards when used on baits. The most widely known product containing DRC- 1339 is Purina Mills’ Starlicide Complete¼, a pelleted bait used to control blackbirds and starlings in feedlots. Other DRC- 1339 registrations are held by the U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA/APHIS), for the use of nonpelletized baits at feedlots and for the control of gulls in or near their nesting colonies. Over 20 State Special Local Need 24(c) registrations have also been issued to APHIS for special DRC-1339 uses. To consolidate these registrations, APHIS has submitted data to amend its feedlot registration for blackbirds and starlings, and applied for three registrations for control of 1) raven and crow depredations on livestock and for wildlife protection, 2) pigeons in and around structures, and 3) blackbirds, starlings, and crows at preroosting staging areas. Because most of the submitted data were collected in the 1960s and 1970s, none of it was produced under the Environmental Protection Agency\u27s (EPA) Good Laboratory Practices (GLP) regulations; therefore, new data will probably be needed to support these registrations. Future data needs and procedures for collecting valid information for DRC-1339 are suggested

    Benefit-cost methodology study with example application of the use of wind generators

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    An example application for cost-benefit methodology is presented for the use of wind generators. The approach adopted for the example application consisted of the following activities: (1) surveying of the available wind data and wind power system information, (2) developing models which quantitatively described wind distributions, wind power systems, and cost-benefit differences between conventional systems and wind power systems, and (3) applying the cost-benefit methodology to compare a conventional electrical energy generation system with systems which included wind power generators. Wind speed distribution data were obtained from sites throughout the contiguous United States and were used to compute plant factor contours shown on an annual and seasonal basis. Plant factor values (ratio of average output power to rated power) are found to be as high as 0.6 (on an annual average basis) in portions of the central U. S. and in sections of the New England coastal area. Two types of wind power systems were selected for the application of the cost-benefit methodology. A cost-benefit model was designed and implemented on a computer to establish a practical tool for studying the relative costs and benefits of wind power systems under a variety of conditions and to efficiently and effectively perform associated sensitivity analyses

    NOTES: BED-SITE SELECTION BY NEONATAL WHITE-TAILED DEER IN CENTRAL NORTH DAKOTA

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    Understanding bed-site selection and vegetation characteristics provides valuable information for population management (Verme 1977, Huegel et al. 1985a, Nelson and Woolf 1987). Predation and other natural-caused mortalities of white-tailed deer (Odocoileus virginianus) neonates are most likely to occur within the first 60 days of life; a time period when selected habitat characteristics are vital to survival (Verme 1977, Hue- gel et al. 1985a, Nelson and Woolf 1987, Grovenburg et al. 2010). Prior to the study of Grovenburg et al. (2010), limited research had been completed on the bed-site selection of neonatal white-tailed deer in the grasslands of the Northern Great Plains. In north-central South Dakota, increase in vertical height of vegetation was the most important habitat characteristic at bed sites, which likely pertained directly to protection from predation and thermal insulation (Grovenburg et al. 2010, 2012a). Our objective was to describe the physical and vegetative characteristics of bed sites selected by neonatal white-tailed deer in the grassland dominated landscape of central North Dakota. We hypothesized that neonatal white-tailed deer would select bed sites characterized by relatively high understory vegetation to moderate ambient temperatures resulting in favorable microclimates for maintaining thermal neutrality while providing concealment from predators. We studied neonatal white-tailed deer in Burleigh County in central North Dakota, which comprised an area of 2,652 km2. The study area was located within the Northwestern Glaciated Plains level III Ecoregion (Bryce et al. 1998) and was characterized by significant surface irregularity and high concentration of wetlands (United States Department of Agriculture 2011). Long-term (30-year) mean summer temperatures ranged from 13.1° C to 27.5° C and mean (30- year) annual precipitation was 44.9 cm (North Dakota State Climate Office 2012). Nearly all land within the region was used for agricultural purposes. Grasslands and croplands dominated the landscape at 66.2% and 21.0%, respectively. Additionally, wetlands and water comprised 7.4%, developed land 5.2%, and other land uses \u3c1% of the landscape (United States Department of Agriculture 2011). Furthermore, Burleigh County had 4,884 ha in Wildlife Management Areas, 6,844 ha in National Wildlife Refuges, and 4,546 ha in Waterfowl Production Areas (C. Penner, North Dakota Game and Fish Department, personal communication)

    Mental Health Status and Perceived Barriers to Seeking Treatment in Rural Reserve Component Veterans

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    National Guard and Reserve (RC) troops (N=617) primarily from the Appalachian Region in Southwestern Pennsylvania who recently returned from deployment in support of current military conflicts responded to a survey that assessed their demographics, mental health symptoms, help-seeking behaviors, barriers for not seeking treatment, deployment history, and stressors. Veterans were classified as rural (N = 334) or non-rural (N = 283). Rural participants reported a significantly greater number of issues with transportation/access in seeking mental health treatment, were more likely to perceive others as worse off as a reason not to seek treatment, had a more negative attitude toward seeking treatment for mental health problems, and reported fewer concerns about a mental health problem affecting their career. Recommendations for mental health care providers and policymakers are offered based on the results, including the importance of recognizing the distinctive barriers to care that RC Appalachian veterans face when they come back into civilian communities, many of them rural

    Learning from the children : exploring preschool children's encounters with ICT at home

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    This paper is an account of our attempts to understand preschool children's experiences with information and communication technologies (ICT) at home. Using case study data, we focus on what we can learn from talking directly to the children that might otherwise have been overlooked and on describing and evaluating the methods we adopted to ensure that we maximised the children's contributions to the research. By paying attention to the children's perspectives we have learned that they are discriminating users of ICT who evaluate their own performances, know what gives them pleasure and who differentiate between operational competence and the substantive activities made possible by ICT
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