1,511 research outputs found

    The Rostock Energetic Feed Evaluation on the Base of Net Energy

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    Feed evaluation was an emphasis of research from the foundation of the Oskar-Kellner-Institute of Animal Nutrition in 1953 at Rostock by Prof. Kurt Nehring. The aim of the research work was the elaboration of a feed evaluation system containing reference numbers of feed values and requirements of farm animals. The approach and the present system are outlined in this paper

    Long Term Observation of the Grassland Vegetation Used Intensively or Extensively and Ecologically

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    The aim of the present paper was to study alterations of the grassland flora from 55 plots following a more extensive management under long term observation within 6 years. Extensification of grassland use leads to an increase of the numbers of plant species by 32%, “Red-list-species” included. The moisture number of the soils slightly increased and the reaction and nitrogen numbers decreased. Results are presented for different vegetation units

    Influence of Grassland Management and Grazing by Different Farm Animals on Animal Performance and Flora Alterations

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    The objectives of this study were to test the possibilities of using different farm animals for landscape care on extensive pasture, taking into account their particular performance, and to analyse alterations of the flora in consequence of grazing by different animals and various pasture management. Salers had the highest (836g/d) and Galloways (584g/d) the lowest live weight gain as compared with the other breeds (771g/d). Lambs had higher live weight when grazing together with cattle and horses (mixed grazing) than under one species grazing. The number of legume increased and that of grass decreased. Following 3 years the grazing animals effected an increase of plant numbers in order of: Horses 86%, Cattle 15%, Mixed grazing 14% and sheep no effect. The most success of increasing plant numbers was registered when combined grazing and mowing of pasture was used

    Gauss sum factorization with cold atoms

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    We report the first implementation of a Gauss sum factorization algorithm by an internal state Ramsey interferometer using cold atoms. A sequence of appropriately designed light pulses interacts with an ensemble of cold rubidium atoms. The final population in the involved atomic levels determines a Gauss sum. With this technique we factor the number N=263193.Comment: 4 pages, 5 figure

    Versatile compact atomic source for high resolution dual atom interferometry

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    We present a compact 87^{87}Rb atomic source for high precision dual atom interferometers. The source is based on a double-stage magneto-optical trap (MOT) design, consisting of a 2-dimensional (2D)-MOT for efficient loading of a 3D-MOT. The accumulated atoms are precisely launched in a horizontal moving molasses. Our setup generates a high atomic flux (>1010>10^{10} atoms/s) with precise and flexibly tunable atomic trajectories as required for high resolution Sagnac atom interferometry. We characterize the performance of the source with respect to the relevant parameters of the launched atoms, i.e. temperature, absolute velocity and pointing, by utilizing time-of-flight techniques and velocity selective Raman transitions.Comment: uses revtex4, 9 pages, 12 figures, submitted to Phys. Rev.

    Differential atom interferometry beyond the standard quantum limit

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    We analyze methods to go beyond the standard quantum limit for a class of atomic interferometers, where the quantity of interest is the difference of phase shifts obtained by two independent atomic ensembles. An example is given by an atomic Sagnac interferometer, where for two ensembles propagating in opposite directions in the interferometer this phase difference encodes the angular velocity of the experimental setup. We discuss methods of squeezing separately or jointly observables of the two atomic ensembles, and compare in detail advantages and drawbacks of such schemes. In particular we show that the method of joint squeezing may improve the variance by up to a factor of 2. We take into account fluctuations of the number of atoms in both the preparation and the measurement stage, and obtain bounds on the difference of the numbers of atoms in the two ensembles, as well as on the detection efficiency, which have to be fulfilled in order to surpass the standard quantum limit. Under realistic conditions, the performance of both schemes can be improved significantly by reading out the phase difference via a quantum non-demolition (QND) measurement. Finally, we discuss a scheme using macroscopically entangled ensembles.Comment: 10 pages, 5 figures; eq. (3) corrected and other minor change

    Pennsylvania Folklife Vol. 24, No. 1

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    • Some Early Moravian Builders in America • Old Order Mennonite Family Life in the East Penn Valley • Historic Yellow Springs: The Restoration of an American Spa • The Use of Speech at Two Auctions • Pennsylvania German Astronomy and Astrology IX: Johann Friederich Schmidt • Courtship and Marriage: Folk-Cultural Questionnaire No. 36https://digitalcommons.ursinus.edu/pafolklifemag/1060/thumbnail.jp

    Pinpointing deep geothermal upflow in zones of complex tectono-volcanic degassing : new insights from Aluto volcano, Main Ethiopian Rift

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    The project was financed in the framework of the Volkswagen Foundation’s „Postdoctoral Fellowships for African Researchers in the Engineering Sciences“ (Reference: 90017).Active rifts release large amounts of gases from deep sources to the atmosphere by advection and diffusion processes along permeable fracture zones. The objective of this study is to develop geothermal exploration concepts for areas with little or no hydrothermal surface expressions suitable for fluid sampling and analyses (e.g., hot springs, geysers, and fumaroles). In such areas, soil gas surveys can complement established geophysical and geochemical exploration. We report CO2, 222Rn (Radon) and 220Rn (Thoron) emission data and ground temperatures from the Aluto volcanic complex in the Main Ethiopian Rift to improve understanding of tectonic and volcanic controls on the existing geothermal system. This suite of gas emission measurements allows us to identify major, deep‐rooted permeable structures with active fluid circulation and identify suitable drilling targets for geothermal production wells on Aluto. We show that significant differences in gas signatures (i.e., efflux and spatial pattern) can be used to identify predominantly volcanically and/or tectonically influenced compartments. Major gas emissions indicate significant fluid circulation at depth, which is typical for magmatic systems. Such high gas emissions have been observed in areas affected by major tectonic structures interacting with magmatic bodies at depth (tectono‐volcanic). Predominantly fault‐controlled sectors also show hydrothermal fluid circulation, but to a lower extent compared to tectono‐volcanic sectors. Within the Aluto volcanic complex geothermal production wells mainly target such fault‐controlled domains, whereas results of the study indicate strongest fluid circulation in tectono‐volcanic sectors. This result should be considered for the future exploration and development strategy of the site.Publisher PDFPeer reviewe

    Pulmonary vasoconstrictor action of KCNQ potassium channel blockers

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    KCNQ channels have been widely studied in the nervous system, heart and inner ear, where they have important physiological functions. Recent reports indicate that KCNQ channels may also be expressed in portal vein where they are suggested to influence spontaneous contractile activity. The biophysical properties of K+ currents mediated by KCNQ channels resemble a current underlying the resting K+ conductance and resting potential of pulmonary artery smooth muscle cells. We therefore investigated a possible role of KCNQ channels in regulating the function of pulmonary arteries by determining the ability of the selective KCNQ channel blockers, linopirdine and XE991, to promote pulmonary vasoconstriction. Linopirdine and XE991 both contracted rat and mouse pulmonary arteries but had little effect on mesenteric arteries. In each case the maximum contraction was almost as large as the response to 50 mM K+. Linopirdine had an EC50 of around 1 μM and XE991 was almost 10-fold more potent. Neither removal of the endothelium nor exposure to phentolamine or α,β-methylene ATP, to block α1-adrenoceptors or P2X receptors, respectively, affected the contraction. Contraction was abolished in Ca2+-free solution and in the presence of 1 μM nifedipine or 10 μM levcromakalim

    A novel proviral clone of HIV-2: Biological and phylogenetic relationship to other primate immunodeficiency viruses.

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    Infectious molecular clones of the human immunodeficiency virus type 2 (HIV-2) will be valuable tools for the study of regulatory gene functions and the development of an animal model for the human acquired immunodeficiency syndrome (AIDS). To this end, we have cloned and sequenced a novel HIV-2 isolate, HIV-2BEN. One clone, designated MK6, is infectious for various human T-cell lines and for human and macaque peripheral blood lymphocytes (PBL), allowing molecular studies of HIV-2 infection and replication. Since MK6 is highly cytopathic in MT-2 and Molt-4 clone 8 cells, antiviral agents and neutralizing sera may be tested. Cluster analysis of HIV-1, HIV-2, and simian immunodeficiency virus (SIV) env and gag genes revealed that HIV-2BEN yielded the earliest node of phylogenetic divergence for all reported HIV-2 sequences. Noise analysis showed that, with the current data, no specification of any branching order can be made among the four groups of primate lentiviruses, HIV-1, HIV-2/SIVSMM/MAC, SIVAGM, and SIVMND
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