12,457 research outputs found

    Microscopic optical potential from chiral nuclear forces

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    The energy- and density-dependent single-particle potential for nucleons is constructed in a medium of infinite isospin-symmetric nuclear matter starting from realistic nuclear interactions derived within the framework of chiral effective field theory. The leading-order terms from both two- and three-nucleon forces give rise to real, energy-independent contributions to the nucleon self-energy. The Hartree-Fock contribution from the two-nucleon force is attractive and strongly momentum dependent, in contrast to the contribution from the three-nucleon force which provides a nearly constant repulsive mean field that grows approximately linearly with the nuclear density. Together, the leading-order perturbative contributions yield an attractive single-particle potential that is however too weak compared to phenomenology. Second-order contributions from two- and three-body forces then provide the additional attraction required to reach the phenomenological depth. The imaginary part of the optical potential, which is positive (negative) for momenta below (above) the Fermi momentum, arises at second-order and is nearly inversion-symmetric about the Fermi surface when two-nucleon interactions alone are present. The imaginary part is strongly absorptive and requires the inclusion of an effective mass correction as well as self-consistent single-particle energies to attain qualitative agreement with phenomenology.Comment: 12 pages, 7 figures, added references, corrected typo

    Comparison of rocket-borne probes for electron density measurements Quarterly status report no. 5, Aug. 1 - Oct. 31, 1965

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    Impedance, resonance, capacitance, electrostatic, and Langmuir probe performance for ionospheric electron density profil

    Autumn Twilight : Reverie D\u27Amour

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    https://digitalcommons.library.umaine.edu/mmb-ps/1382/thumbnail.jp

    Sweet Sabbath Bells : Fantaisie de Concert

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    https://digitalcommons.library.umaine.edu/mmb-ps/3292/thumbnail.jp

    Quantum-limited mass flow of liquid 3^{3}He

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    We consider theoretically the possibility of observing unusual quantum fluid behavior in liquid 3^{3}He and solutions of 3^{3}He in 4^{4}He systems confined to nano-channels. In the case of pure ballistic flow at very low temperature conductance will be quantized in units of 2m2/h2m^{2}/h. We show that these steps should be sensitive to increases in temperature. We also use of a random scattering matrix simulation to study flow with diffusive wall scattering. Universal conductance fluctuations analogous to those seen in electron systems should then be observable. Finally we consider the possibility of the cross-over to a one-dimensional system at sufficiently low temperature where the system could form a Luttinger liquid

    Integrated cost-benefit analysis of tsetse control and herd productivity to inform control programs for animal African trypanosomiasis

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    Animal African trypanosomiasis (AAT) and its tsetse vector are responsible for annual losses estimated in billions of US dollars ($). Recent years have seen the implementation of a series of multinational interventions. However, actors of AAT control face complex resource allocation decisions due to the geographical range of AAT, diversity of ecological and livestock systems, and range of control methods available. The study presented here integrates an existing tsetse abundance model with a bio-economic herd model that captures local production characteristics as well as heterogeneities in AAT incidence and breed. These models were used to predict the impact of tsetse elimination on the net value of cattle production in the districts of Mambwe, in Zambia, and Faro et Déo in Cameroon. The net value of cattle production under the current situation was used as a baseline, and compared with alternative publicly funded control programmes. In Zambia, the current baseline is AAT control implemented privately by cattle owners (Scenario Z0). In Cameroon, the baseline (Scenario C0) is a small-scale publicly funded tsetse control programme and privately funded control at farm level. The model was run for 10 years, using a discount rate of 5%

    Vascular Smooth Muscle as a Therapeutic Target in Disease Pathology

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    Our circulatory system is composed of numerous elements that are responsible for transport of blood and delivery of essential nutrients and gases to vital downstream tissues. Among these components that make up our circulation is vascular smooth muscle (VSM), the primary muscular and contractile element of blood vessels and regulator of many blood vessel functions. This is of particular importance as cardiovascular disease (CVD), the number one killer of individuals in America and worldwide, is primarily vascular in origin. Logically, identifying and characterizing feasible targets that could control CVD are highly appealing and much desired. With this in mind and given its centrality in control of vascular physiology, VSM has gained wide attention as a plausible target to combat elements of CVD. This book chapter focuses on VSM as a potential therapeutic target against CVD and will provide overview of vascular anatomy and physiology and brief discussions about the pivotal roles of VSM in CVD pathology, the influence of abnormal blood flow mechanics and hemodynamics in CVD, neural control of VSM and the vasculature, and possible novel cellular and molecular signaling targets that could be used to control and/or minimize CVD. This chapter hopes to serve as a valuable resource for basic and applied scientists as well as clinicians interested in understanding the crucial roles that VSM plays in vessel physiology and pathology
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