1,212 research outputs found

    Study of ground state phases for spin-1/2 Falicov-Kimball model on a triangular lattice

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    The spin-dependent Falicov-Kimball model (FKM) is studied on a triangular lattice using numerical diagonalization technique and Monte-Carlo simulation algorithm. Magnetic properties have been explored for different values of parameters: on-site Coulomb correlation UU, exchange interaction JJ and filling of electrons. We have found that the ground state configurations exhibit long range Ne\`el order, ferromagnetism or a mixture of both as JJ is varied. The magnetic moments of itinerant (dd) and localized (ff) electrons are also studied. For the one-fourth filling case we found no magnetic moment from dd- and ff-electrons for UU less than a critical value.Comment: 6 pages, 8 figure

    Farm management in relation to land use, soil conservation and soil type, Crockett county, Tennessee

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    In some sections of the country agriculture has not been able to keep pace with industry and commerce in the advance of living conditions and cultural opportunities and in some sections agriculture has become extractive in character, rather than a permanently sustained industry. This is not conducive to the best permanent development of farm life, nor in harmony with the principles of farm management and agricultural policy. The purpose of this study is to analyze farm organization and farm practices in West Tennessee, in relation to land use and determine their effect on the soil with a view to determining the different kinds and amounts of the several crops and classes livestock that may best be combined in order to secure the most continuous profitable operation of the farms. To do this it has been necessary to study needed soil conservation practices, proper land use, desirable fertility measures, approved crop rotations, profitable degree of diversity, and other farm practices in relation to the region and so far as possible to individual farms

    Management of Anticoagulation Around Cardiac Implantable Electronic Device Surgery

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    The number of patients requiring cardiovascular implantable electronic device (CIED, e.g., pacemaker and defibrillator) surgery is increasing rapidly and at least a quarter of them are using chronic oral anticoagulation (OAC). Recently, the traditional approach of withholding anticoagulation and using heparin bridging has been challenged by studies showing safety of performing CIED surgery under anticoagulation with vitamin K antagonists. Bridging with heparin is associated with incremental healthcare costs, prolonged hospital admission, and also with an augmented relative risk of pocket hematoma. The risk of embolic events seems to be low and similar with the use of two strategies (heparin bridging and continuous warfarin). Experience with novel oral anticoagulants is limited. Few studies suggest that withholding 48–72 hours before surgery and performing the procedure under anticoagulation are safe alternatives. However, larger randomized clinical trials are needed before definitive conclusions. In this chapter, we review the management of anticoagulation around cardiac implantable electronic device surgery under new conditions

    Interface induced perpendicular magnetic anisotropy in Co/CoO/Co thin film structure: An in-situ MOKE investigation

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    Co /CoO/Co polycrystalline film was grown on Si (001) substrate and magnetic properties have been investigated using in-situ magneto-optic Kerr effect during growth of the sample. Magnetic anisotropy with easy axis perpendicular to the film surface has been observed in top Co layer, whereas bottom layer was found to be soft with in-plane magnetization without any influence of top layer. Ex-situ in-plane and out-of-plane diffraction measurements revealed that the growth of Co on oxidized interface takes place with preferential orientation of c-axis perpendicular to the film plane, which results in the observed perpendicular magnetic anisotropy. Texturing of the c-axis is expected to be a result of minimization of the interface energy due to hybridization between Co and oxygen at the interface.Comment: 9 pages, 3 figures, under review in IOP journa

    Pattern and predictability of potential wind assistance for waders and geese migrating from West Africa and the Wadden Sea to Siberia

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    Analysed published wind data from the period 1979-1991 to evaluate to what extent migrating waders and geese might benefit from tailwind assistance when flying at altitudes ranging from ground level up to 5.5 km from West Africa (Banc d'Arguin, Mauritania) to the Wadden Sea (Netherlands, Germany and Denmark) in late April and early May, and from the Wadden Sea to Taymyr Peninsula (Siberia) in late May and early June. Between West Africa and the Wadden Sea it is usually advantageous to fly high, with an average tailwind of 15 km/h (mean of yearly averages) for those birds flying along the optimal height track. There were large differences between years though, with 36 km/h tailwind (1983) and 2 km/h headwind (1991) as extreme values. Best altitudes for migration were higher along the northwest African coast than over Europe. There was no evidence for consistent seasonal changes in wind favourability, but "bad' years were consistently bad over the whole season. Between the Wadden Sea and the Taymyr Peninsula wind conditions were better still than for the Banc d'Arguin-to-Wadden Sea journey (long term average for flights along optimal height track is 21 km/h tailwind), with the favourable winds found at intermediate altitudes (1.5-3 km). -from Authors</p
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