1,175 research outputs found
The topological uniqueness of the deltahedra found in the boranes BnHn2ā (6ā¤nā¤12)
The deltahedra observed experimentally in the borane anions BnHn2ā (6ā¤nā¤12) are the only possible n-vertex deltahedra having only degree 4 and 5 vertices. The existence of an 11-vertex deltahedron having only degree 4 or 5 vertices is topologically impossible in accord with the presence of a degree 6 vertex in the observed structure for B11H112ā
Asiatic Wild Asses in the Literature: What Do We Need to Know Now?
Asiatic wild asses were once found across central Asia, but over time their range has been reduced until today all subspecies are under threat. This paper examined the literature about wild asses with an aim to illustrating gaps in our knowledge as a target for future research.
A search was made on BIOSIS ISI for the following strings: Equus hemionus, wild ass, khulan, kulan, kiang, khur, and onager. In total 61 relevant references were found, published between 1900 and 2005. Most of these references were published in the 1990s, with only one published between 1900 and 1970. Khur and khulan were most under-represented in the literature with only five and two citations respectively resulting from these key words. When put into subjective categories most papers published (28) were on the conservation, behavior or ecology of Asiatic wild asses. All physiology papers dealt with captive animals, and nearly half of all genetics papers focused on onagers. Very little was published on the habitat use of wild asses and there was almost nothing on the distribution of subspecies, or genetic differences between them. This research highlighted the importance of key words and consistent nomenclature. We need to focus more on the ecology of wild populations, in particular examining habitat use, social structure and distribution. In addition it is very important that more is published on threats to these animals so that action can be taken in time
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Agricultural development prospects in Belize (NRI Bulletin 48)
This report is one ofthree documents completing the land resource assessment of Belize undertaken by the Natural Resources Institute (NRI)from 1986-90. The other documents are: (i) a revised national soil classification (Baillie et al., 1993) (ii) an update on 'Land in British Honduras' (Wright et al., 1959), which will present inter alia much of the NRI land resource assessment findings in a more easily readable format (Wright et al., 1993). The aim of this report is to assess the entireĀ·Ā·agricultural resources of the country, present an assessment of how they can be used to best effect, both in the short(economically) and long terms (by protecting the environment), and present a 1:500 000 scale map indicating the preferred use for each part of the country (Map 1 ). Map 1 does not take into account current ownership, except in the case of Programme for Belize, where it is assumed that organization will continue to manage the Rio Bravo Conservation Management Area. This report also includes advice on how a Geographical Information System (GIS) can be used to update the NRI surveys and provide additional data so that the suitability of new crops and the effect of changed economic circumstances can be determined from the land resource assessment database
Emerging Tools to Control Feral Horse Populations in the Western USA
The U.S. Geological Survey (USGS) has been conducting research to support the Bureau of Land Management (BLM) Wild Horse and Burro Program since 1996 and is currently engaged in testing additional tools to curb high population growth of feral horses. Horses are protected by the Wild and Free-Roaming Horses and Burros Act of 1971 and are managed to maintain populations at appropriate management level (AML). With no natural predators, many populations double in 4-5 years. Population size is controlled primarily with āgathersā in which horses are rounded up and made available for adoption by the public. This is a costly enterprise in which animals are housed in holding facilities while they await potential adoption and many horses are never adopted. Today ~48,000 horses remain in holding facilities across the USA, and facilities are now full. There are approximately 72,000 horses on public lands across the west, which is almost 3 times range wide AML. Horses have profound impacts on habitat and other wildlife, and the situation is becoming critical on western landscapes. With holding facilities at capacity, BLM is forced to leave excess animals on public lands, leading to rangeland degradation and impacts to sage grouse and other wildlife. Solutions are needed quickly to address exponential population growth of horses. USGS partnered with Oklahoma State University (OSU) and Colorado State University (CSU), respectively, to conduct studies testing the efficacy of intrauterine devices (IUD) for horses, and gelding a proportion of males in a population. The IUD study was conducted on 20 domestic mares that were housed with stallions at OSU. Fifteen mares retained IUDs for the 18-month duration of the trial before IUDs were removed. Mares who received progesterone at the time of IUD insertion retained their IUDs, and no mares with an IUD became pregnant. Next we will test IUDs in free-roaming mares. In the gelding study with CSU, there were no differences in individual behavior or movement rates between gelded and non-gelded harem stallions or bachelors after the first breeding season. Gelded harem stallions did not lose their mares at a higher rate than intact stallions, and mares joined gelded harem stallions as often as they joined intact stallions. Preliminary results indicate little if any change to social structure or individual behavior of stallions or mares compared to controls. We will determine after the summer 2019 birthing season if gelding males affects population growth rate. USGS proposed a field study to determine behavior and population growth reduction of sterilizing mares but the study was litigated and postponed. Modeling by USGS indicates sterilization is the most effective and promising tool to reduce herds to AML and would potentially save BLM \u3e$1 billion annually in direct operational costs. The environmental cost to habitat and other wildlife associated with keeping excess horses on the range, as well as direct economic costs, have not yet been calculated for comparison
Space - Radiation Qualification of a Microprocessor Implemented for the Intel 80186
The Intel 80186 sixteen-bit microprocessor is an example of a high performance device (8 MHz) needed to carry out advanced experimentation on Low Earth Orbit missions. However, this key complex microprocessor is not space-qualified. We will discuss the procedures necessary to qualify a microprocessor for the natural space radiation environment. We also present the results from our single event upset tests on the 80186. The upset cross-section exhibited a threshold of 0.4 MeV-cmĀ²/mg, a knee at 7 MeV-cmĀ²/mg and an asymptotic value of 5x10-4cmĀ². The upset cross-section did not depend on frequency in the 4-8 MHz range and increased by 40% when conductive heat sinking was eliminated causing a 50c temperature rise. Finally, we show how to estimate the single event upset rate for a typical low earth orbit mission
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Hanford Waste Vitrification Plant hydrogen generation study: Formation of ammonia from nitrate and nitrate in hydrogen generating systems
The Hanford Waste Vitrification Plant (HWVP) is being designed for the Departrnent of Energy (DOE) to immobilize pretreated highly radioactive wastes in glass for permanent disposal in the HWVP, formic acid is added to the waste before vitrification to adjust glass redox and melter feed rheology. The operation of the glass melter and durability of the glass are affected by the glass oxidation state. Formation of a conductive metallic sludge in an over-reduced melt can result in a shortened melter lifetime. An over-oxidized melt may lead to foaming and loss of ruthenium as volatile RuO{sub 4}. Historically, foaming in the joule heated ceramic melter has been attributed to gas generation in the melt which is controlled by instruction of a reductant such as formic acid into the melter feed. Formic acid is also found to decrease the melter feed viscosity thereby facilitating pumping. This technical report discusses the noble metal catalyzed formic acid reduction of nitrite and/or nitrate to ammonia, a problem of considerable concern because of the generation of a potential ammonium nitrate explosion hazard in the plant ventilation system
Chiral Effective Field Theory Calculations of Weak Transitions in Light Nuclei
We report quantum Monte Carlo calculations of weak transitions in A 10 nuclei, based on the Norfolk two-and three-nucleon chiral interactions, and associated one-and two-body axial currents. We find that the contribution from two-body currents is at the 2-3% level, with the exception of matrix elements entering the rates of Li-8, B-8, and He-8 beta decay. These matrix elements are suppressed in impulse approximation based on the (leading order) Gamow Teller transition operator alone; two-body currents provide a 20-30% correction, which is, however, insufficient to bring theory in agreement with experimental data. For the other transitions, the agreement with the data is satisfactory, and the results exhibit a negligible to mild model dependence when different combinations of Norfolk interactions are utilized to construct the nuclear wave functions. We report a complete study of two-body weak transition densities which reveals the expected universal behavior of two-body currents at short distances throughout the range of A = 3 to A = 10 systems considered here
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Land resource assessment of Northern Belize (NRI Bulletin 43, Volume 1 of 2)
The land resource assessment was undertaken from July 1989 to June 1990 by the Natural Resources Institute (NRI) of the Overseas Development Administration (ODA), assisted by Mr. A. C. S. Wright, and Dr. M. Holder of Central Farm. The main object of the survey was to produce an updated land suitability assessment of Orange Walk, Corozal, Belize and Cayo districts which had not already been surveyed by Jenkin et al. (1976) and King et al. (1989). In addition, this survey would provide a land suitability assessment for the Belize Valley based on the soil mapping of )en kin et al. Thus, together with the land resource assessments of Toledo and Stann Creek districts (King et al., 1986, 1989 respectively), a land suitability assessment for the whole of Belize is now available
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Land resource assessment of Northern Belize (NRI Bulletin 43, Volume 2 of 2)
The land resource assessment was undertaken from July 1989 to June 1990 by the Natural Resources Institute (NRI) of the Overseas Development Administration (ODA), assisted by Mr. A. C. S. Wright, and Dr. M. Holder of Central Farm. The main object of the survey was to produce an updated land suitability assessment of Orange Walk, Corozal, Belize and Cayo districts which had not already been surveyed by Jenkin et al. (1976) and King et al. (1989). In addition, this survey would provide a land suitability assessment for the Belize Valley based on the soil mapping of )en kin et al. Thus, together with the land resource assessments of Toledo and Stann Creek districts (King et al., 1986, 1989 respectively), a land suitability assessment for the whole of Belize is now available
Transport study of intense-laser-produced fast electrons in solid targets with a preplasma created by a long pulse laser
Copyright 2010 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 17(6), 060704, 2010 and may be found at http://dx.doi.org/10.1063/1.344787
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