27,976 research outputs found

    A critical analysis of the hydrino model

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    Recently, spectroscopic and calorimetric observations of hydrogen plasmas and chemical reactions with them have been interpreted as evidence for the existence of electronic states of the hydrogen atom with a binding energy of more than 13.6 eV. The theoretical basis for such states, that have been dubbed hydrinos, is investigated. We discuss both, the novel deterministic model of the hydrogen atom, in which the existence of hydrinos was predicted, and standard quantum mechanics. Severe inconsistencies in the deterministic model are pointed out and the incompatibility of hydrino states with quantum mechanics is reviewed.Comment: 9 page

    Differential temperature cryogenic liquid level sensing system Final report

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    Differential temperature cryogenic liquid level sensing system design and developmen

    Religious Relationships with the Environment in a Tibetan Rural Community : Interactions and Contrasts with Popular Notions of Indigenous Environmentalism

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    Acknowledgments: We thank Beijing Forestry University, our field assistants Tashi Rabden, Pema Dechin, Tsewang Chomtso and Gele Chopel for their invaluable help, the Forest Bureau of Daocheng county for permission and support, and the people of Samdo for their hospitality and participation. The research was funded by the ESRC and the World Pheasant Association. This paper is a contribution to Imperial College’s Grand Challenges in Ecosystems and the Environment initiative. Two anonymous reviewers gave valuable comments on the manuscript.Peer reviewedPublisher PD

    Links between soil microbial communities and plant traits in a species-rich grassland under long-term climate change

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    Climate change can influence soil microorganisms directly by altering their growth and activity but also indirectly via effects on the vegetation, which modifies the availability of resources. Direct impacts of climate change on soil microorganisms can occur rapidly, whereas indirect effects mediated by shifts in plant community composition are not immediately apparent and likely to increase over time. We used molecular fingerprinting of bacterial and fungal communities in the soil to investigate the effects of 17 years of temperature and rainfall manipulations in a species‐rich grassland near Buxton, UK. We compared shifts in microbial community structure to changes in plant species composition and key plant traits across 78 microsites within plots subjected to winter heating, rainfall supplementation, or summer drought. We observed marked shifts in soil fungal and bacterial community structure in response to chronic summer drought. Importantly, although dominant microbial taxa were largely unaffected by drought, there were substantial changes in the abundances of subordinate fungal and bacterial taxa. In contrast to short‐term studies that report high resistance of soil fungi to drought, we observed substantial losses of fungal taxa in the summer drought treatments. There was moderate concordance between soil microbial communities and plant species composition within microsites. Vector fitting of community‐weighted mean plant traits to ordinations of soil bacterial and fungal communities showed that shifts in soil microbial community structure were related to plant traits representing the quality of resources available to soil microorganisms: the construction cost of leaf material, foliar carbon‐to‐nitrogen ratios, and leaf dry matter content. Thus, our study provides evidence that climate change could affect soil microbial communities indirectly via changes in plant inputs and highlights the importance of considering long‐term climate change effects, especially in nutrient‐poor systems with slow‐growing vegetation

    Ecologic studies of rodent reservoirs: their relevance for human health.

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    Within the past few years, the number of "new" human diseases associated with small-mammal reservoirs has increased dramatically, stimulating renewed interest in reservoir ecology research. A consistent, integrative approach to such research allows direct comparisons between studies, contributes to the efficient use of resources and data, and increases investigator safety. We outline steps directed toward understanding vertebrate host ecology as it relates to human disease and illustrate the relevance of each step by using examples from studies of hosts associated with rodent-borne hemorrhagic fever viruses

    Landau Collision Integral Solver with Adaptive Mesh Refinement on Emerging Architectures

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    The Landau collision integral is an accurate model for the small-angle dominated Coulomb collisions in fusion plasmas. We investigate a high order accurate, fully conservative, finite element discretization of the nonlinear multi-species Landau integral with adaptive mesh refinement using the PETSc library (www.mcs.anl.gov/petsc). We develop algorithms and techniques to efficiently utilize emerging architectures with an approach that minimizes memory usage and movement and is suitable for vector processing. The Landau collision integral is vectorized with Intel AVX-512 intrinsics and the solver sustains as much as 22% of the theoretical peak flop rate of the Second Generation Intel Xeon Phi, Knights Landing, processor

    An experimental/analytical program to assess the utility of lidar for pollution monitoring

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    The development and demonstration of lidar techniques for the remote measurement of atmospheric constituents and transport processes in the lower troposphere was carried out. Particular emphasis was given to techniques for monitoring SO2 and particulates, the principal pollutants in power plant and industrial plumes. Data from a plume dispersion study conducted in Maryland during September and October 1976 were reduced, and a data base was assembled which is available to the scientific community for plume model verification. A UV Differential Absorption Lidar (DIAL) was built, and preliminary testing was done

    Quantum ratchet transport with minimal dispersion rate

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    We analyze the performance of quantum ratchets by considering the dynamics of an initially localized wave packet loaded into a flashing periodic potential. The directed center-of-mass motion can be initiated by the uniform modulation of the potential height, provided that the modulation protocol breaks all relevant time- and spatial reflection symmetries. A poor performance of quantum ratchet transport is characterized by a slow net motion and a fast diffusive spreading of the wave packet, while the desirable optimal performance is the contrary. By invoking a quantum analog of the classical P\'eclet number, namely the quotient of the group velocity and the dispersion of the propagating wave packet, we calibrate the transport properties of flashing quantum ratchets and discuss the mechanisms that yield low-dispersive directed transport.Comment: 6 pages; 3 figures; 1 tabl
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