2,317 research outputs found

    The world wide spread of space technology

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    Space technological capabilities and developments in US, USSR, Western Europe, Japan, China, and developing nation

    An Evolution in Regional Airline Training Programs

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    A brief overview of how Republic Airline training programs are evolving to include our new training center and iPad based products being launched to enhance training for current and future pilots

    Conflict Resolution in the Assignment of Area Entitlements for Seabed Mining

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    This Article examines the conditions creating a need for, and the procedures being implemented to achieve, resolution of conflicts over deep seabed areas sought for exclusive exploration entitlements. The author argues that if and when deep seabed mining takes place, certain tangible advantages will accrue to nations or organizations that have obtained entitlements to exclusivity of activity within areas of the seabed. The author further suggests that the development of legal assurances of exclusivity and security of work within a claimed area has been proceeding along two different tracks, the 1982 Convention, and a prospectively complementary but currently separate and potentially competing entitlement system based on domestic laws, multilateral arrangements, and private agreements. The author argues that successful resolution in either track could facilitate progress in the other, and arrangements developed through efforts in the separate tracks could contribute eventually to a convergence of the two legal regulatory regimes

    Filter strip performance and processes for different vegetation, widths, and contaminants

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    Filter strips are widely prescribed to reduce contaminants in surface runoff from agricultural fields. Tbis study compared performance of different filter strip designs on several contaminants and evaluated the contribnting processes. Different vegetation types and widths were investigated using simulated runoff event on large plots (3 m X 7.5 or 15 m) having fine-textured soil and a 6 to 7% slope. Filter strips 7.5 and 15 m wide downslope greatly reduced concentrations of sediment in runoff (76-93%) and contaminants strongly associated with sediment (total P, 55-79%; permethrin, 27-83% [(3-phenoxyphenyl) methyl (±)-cis, trans-3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropane carboxylate ]). They had less effect on concentrations of primarily dissolved contaminants [atrazine, -5-43% (2-chloro-4-ethylamino-6- isopropylamino-s-triazine); alachlor, 10-61% [2-chloro-2\u276\u27 -diethylN-( methoxymethyl) acetanilide]; nitrate, 24-48%; dissolved P, 19- 43%; bromide, 13-31 %]. Dilution of runoff by rainfall accounted for most of the rednction of concentration of dissolved contaminants. Infiltration (36-82% ofrunoffvolume) substantially reduced the mass of contaminants exiting the filter strips. Doubling filter strip width from 7.5 to 15 m doubled infiltration and dilution, but did not improve sediment settling. Y onng trees and shrubs planted in the lower onehalf of otherwise grass strips had no impact on filter performance. Compared with cultivated sorghum [Sorghum bicolor (L.) Moench] grass clearly reduced concentrations of sediment and associated contaminants in runoff, but not volume of runoff and concentration of dissolved contaminants. Settling, infiltration, and dilution processes can explain performance differences among pollutant types and filter strip designs

    Mechanisms of Surviving Burial: Dune Grass Interspecific Differences Drive Resource Allocation After Sand Deposition

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    Sand dunes are important geomorphic formations of coastal ecosystems that are critical in protecting human populations that live in coastal areas. Dune formation is driven by ecomorphodynamic interactions between vegetation and sediment deposition. While there has been extensive research on responses of dune grasses to sand burial, there is a knowledge gap in understanding mechanisms of acclimation between similar, coexistent, dune-building grasses such as Ammophila breviligulata (C3), Spartina patens (C4), and Uniola paniculata (C4). Our goal was to determine how physiological mechanisms of acclimation to sand burial vary between species. We hypothesize that (1) in the presence of burial, resource allocation will be predicated on photosynthetic pathway and that we will be able to characterize the C3 species as a root allocator and the C4 species as leaf allocators. We also hypothesize that (2) despite similarities between these species in habitat, growth form, and life history, leaf, root, and whole plant traits will vary between species when burial is not present. Furthermore, when burial is present, the existing variability in physiological strategy will drive species-specific mechanisms of survival. In a greenhouse experiment, we exposed three dune grass species to different burial treatments: 0 cm (control) and a one-time 25-cm burial to mimic sediment deposition during a storm. At the conclusion of our study, we collected a suite of physiological and morphological functional traits. Results showed that Ammophila decreased allocation to aboveground biomass to maintain root biomass, preserving photosynthesis by allocating nitrogen (N) into light-exposed leaves. Conversely, Uniola and Spartina decreased allocation to belowground production to increase elongation and maintain aboveground biomass. Interestingly, we found that species were functionally distinct when burial was absent; however, all species became more similar when treated with burial. In the presence of burial, species utilized functional traits of rapid growth strategy, although mechanisms of change were interspecifically variable

    Design of Nano-Composites for Ultra-High Strengths and Radiation Damage Tolerance

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    The combination of high strength and high radiation damage tolerance in nanolaminate composites can be achieved when the individual layers in these composites are only a few nanometers thick and therefore these materials contain a large volume fraction associated with interfaces. These interfaces act both as obstacles to slip, as well as sinks for radiation-induced defects. The morphological and phase stabilities of these nano-composites under ion irradiation are explored as a function of layer thickness, temperature and interface structure. Using results on model systems such as Cu-Nb, we highlight the critical role of the atomic structure of the incoherent interfaces that exhibit multiple states with nearly degenerate energies in acting as sinks for radiation-induced point defects. Reduced radiation damage also leads to a reduction in the irradiation hardening, particularly at layer thickness of approximately 5 nm and below. The strategies for design of radiation-tolerant structural materials based on the knowledge gained from this work will be discussed

    Anthropogenic nutrients and harmful algae in coastal waters

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    © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Environmental Management 146 (2014): 206-216, doi:10.1016/j.jenvman.2014.07.002.Harmful algal blooms (HABs) are thought to be increasing in coastal waters worldwide. Anthropogenic nutrient enrichment has been proposed as a principal causative factor of this increase through elevated inorganic and/or organic nutrient concentrations and modified nutrient ratios. We assess: 1) the level of understanding of the link between the amount, form and ratio of anthropogenic nutrients and HABs; 2) the evidence for a link between anthropogenically generated HABs and negative impacts on human health; and 3) the economic implications of anthropogenic nutrient/HAB interactions. We demonstrate that an anthropogenic nutrient-HAB link is far from universal, and where it has been demonstrated, it is most frequently associated with high biomass rather than low biomass (biotoxin producing) HABs. While organic nutrients have been shown to support the growth of a range of HAB species, insufficient evidence exists to clearly establish if these nutrients specifically promote the growth of harmful species in preference to benign ones, or if/how they influence toxicity of harmful species. We conclude that the role of anthropogenic nutrients in promoting HABs is site-specific, with hydrodynamic processes often determining whether blooms occur. We also find a lack of evidence of widespread significant adverse health impacts from anthropogenic nutrient-generated HABs, although this may be partly due to a lack of human/animal health and HAB monitoring. Detailed economic evaluation and cost/benefit analysis of the impact of anthropogenically generated HABs, or nutrient reduction schemes to alleviate them, is also frequently lacking.The work described here is based in part on a project ‘Harmful Algae, Nuisance Blooms and Anthropogenic Nutrient Enrichment’ funded by the UK Department for Environment, Food and Rural Affairs (contract ME2208). In addition KD was supported by the FP7 project Asimuth and funding from the NERC Shelf Seas Biogeochemistry and PURE Associates programmes. PJH was supported by University Grants Council of Hong Kong AoE project (AoE/P-04/0401). PH and LEF were funded by the US National Science Foundation (NSF) Award 1009106; LEF was funded in part by the European Regional Development Fund and European Social Fund (University of Exeter, Truro, Cornwall, UK). GM was supported by a NERC PhD studentship

    Posterior Approach To Kidney Dissection: An Old Surgical Approach For Integrated Medical Curricula

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    Integrated medical curricular changes are altering the historical regional anatomy approach to abdominal dissection. The renal system is linked physiologically and biochemically to the cardiovascular and respiratory systems, yet anatomist often approach the urinary system as part of the abdomen and pelvic regions. As part of an integrated curriculum, the renal system must be covered relatively quickly after the thorax in the cadaver lab, often without the opportunity to fully appreciate the rest of the abdominal contents. This paper provides dissection instructions that follow the one of the historical surgical approaches for nephrectomy, including preservation of the posterior abdominal wall neurovasclature. Dissection procedures were developed for first year medical students, intending this posterior approach to the kidneys to be their first introduction to the renal system. It has been successfully implemented with first year medical students at the University of New England, College of Osteopathic Medicine. Utilizing this posterior approach to the kidney enabled the study of the anatomy of the kidneys, suprarenal glands and renal vessels, as well as the muscles of the lumbar spine, while maintaining the integrity of the anterior abdominal wall and peritoneal cavity for future gastrointestinal and reproductive system-based dissections
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