Dual-mode operation of a neutron source, a concept

Pulsed neutron source operates in conjunction with a photomultiplier tube coupled to a gamma ray scintillation crystal. This allows measurements of gamma radiation from both inelastic scattering and thermal neutron capture in a single experiment

Neutron die-away experiment for lunar and planetary surface analysis Final report, 26 Jul. 1966 - 26 Mar. 1967

Neutron and gamma ray die-away experiment for lunar and planetary surface analysi

Systems effectiveness evaluation program

Eight integrated computer programs provide needed capability to reduce man-hours needed to perform routine monitoring and assessment of effectiveness, reliability, and maintainability of large electronic equipment systems

Computationally-Efficient Visual-Inertial Simultaneous Localization and Mapping for Spaceflight Navigation

This thesis represents an investigation into the application to spaceflight of the estimation techniques developed to solve the well-known robotics problem of Simultaneous Localization and Mapping (SLAM). This subject has been thoroughly studied in the context of ground and aerial robotics but its study for use in the spaceflight domain, where the dynamical, measurement, and computational challenges are often very different than in terrestrial applications, is less common. Further, the wide body of extant robotics research into SLAM can be difficult to approach and understand for space navigators with a more classical estimation background because of the differences in terminology and assumptions that roboticists have utilized over time. This work offers an overview of the development of SLAM in robotics and how it has been applied in that field, as well as an accessible approach to the problem for researchers with an aerospace background. This also leads into the development of a novel visual-inertial (VI) SLAM algorithm designed to achieve constant-time exploration and mapping while still integrating the full nonlinear dynamics of the space environment, handling the high update rates of inertial measurement units (IMUs), and incorporating the measurement information produced by a camera sensor. This algorithm is applied to 2D and 3D simulated and real datasets to demonstrate its capability to quickly generate accurate state estimates of both spacecraft and environmental variables.</p

Efficient decomposition of quantum gates

Optimal implementation of quantum gates is crucial for designing a quantum computer. We consider the matrix representation of an arbitrary multiqubit gate. By ordering the basis vectors using the Gray code, we construct the quantum circuit which is optimal in the sense of fully controlled single-qubit gates and yet is equivalent with the multiqubit gate. In the second step of the optimization, superfluous control bits are eliminated, which eventually results in a smaller total number of the elementary gates. In our scheme the number of controlled NOT gates is $O(4^n)$ which coincides with the theoretical lower bound.Comment: 4 pages, 2 figure

Transmission of bovine viral diarrhea virus among white-tailed deer (Odocoileus virginianus)

Cattle persistently infected (PI) with bovine viral diarrhea virus (BVDV), a pestivirus in the family Flaviviridae, are an important source of viral transmission to susceptible hosts. Persistent BVDV infections have been identified in white-tailed deer (Odocoileus virginianus), the most abundant free-ranging ruminant in North America. As PI deer shed BVDV similarly to PI cattle, maintenance of BVDV within white-tailed deer populations may be possible. To date, intraspecific transmission of BVDV in white-tailed deer has not been evaluated, which prompted this study. Six pregnant white-tailed deer were captured in the first trimester of pregnancy and cohabitated with a PI white-tailed deer. Cohabitation with the PI deer resulted in BVDV infection in all does, as indicated by seroconversion. All does gave birth to live fawns and no reproductive losses were observed. At birth, evidence of BVDV infection was identified in two singlet fawns, of which one was determined to be PI by repeated serum reverse transcription nested PCR, whole blood virus isolation and immunohistochemistry. This study demonstrates for the first time that BVDV transmission may occur among white-tailed deer. The birth of a PI fawn through contact to a PI white-tailed deer indicates that under appropriate circumstances, BVDV may be maintained in white-tailed deer by congenital infection

Monte Carlo study of the Widom-Rowlinson fluid using cluster methods

The Widom-Rowlinson model of a fluid mixture is studied using a new cluster algorithm that is a generalization of the invaded cluster algorithm previously applied to Potts models. Our estimate of the critical exponents for the two-component fluid are consistent with the Ising universality class in two and three dimensions. We also present results for the three-component fluid.Comment: 13 pages RevTex and 2 Postscript figure

Impacts of Climate Change on Multiple Use Management of Bureau of Land Management Land in the Intermountain West, USA

Although natural resource managers are concerned about climate change, many are unable to adequately incorporate climate change science into their adaptation strategies or management plans, and are not always aware of or do not employ the most current scientific knowledge. One of the most prominent natural resource management agencies in the United States is the Bureau of Land Management (BLM), which is tasked with managing over 248 million acres (\u3e1 million km2) of public lands for multiple, often conflicting, uses. Climate change will affect the sustainability of many of these land uses and could further increase conflicts between them. As such, the purpose of our study was to determine the extent to which climate change will affect public land uses, and whether the BLM is managing for such predicted effects. To do so, we first conducted a systematic review of peer-reviewed literature that discussed potential impacts of climate change on the multiple land uses the BLM manages in the Intermountain West, USA, and then expanded these results with a synthesis of projected vegetation changes. Finally, we conducted a content analysis of BLM Resource Management Plans in order to determine how climate change is explicitly addressed by BLM managers, and whether such plans reflect changes predicted by the scientific literature. We found that active resource use generally threatens intrinsic values such as conservation and ecosystem services on BLM land, and climate change is expected to exacerbate these threats in numerous ways. Additionally, our synthesis of vegetation modeling suggests substantial changes in vegetation due to climate change. However, BLM plans rarely referred to climate change explicitly and did not reflect the results of the literature review or vegetation model synthesis. Our results suggest there is a disconnect between management of BLM lands and the best available science on climate change. We recommend that the BLM actively integrates such research into on-the-ground management plans and activities, and that researchers studying the effects of climate change make a more robust effort to understand the practices and policies of public land management in order to effectively communicate the management significance of their findings