3,657 research outputs found

    Effects of different doses of melamine in the diet on melamine concentrations in milk, plasma, rumen fluid, urine and feces in lactating dairy cows

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    The objectives of this paper were to evaluate the effects of feeding diets containing different levels of melamine on melamine concentrations in milk, plasma, rumen fluid, urine and feces in Holstein dairy cows. Sixteen Chinese Holstein dairy cows fixed with permanent ruminal cannulas were assigned to 1 of 4 treatments within a completely randomized design for 10 days. Cows were fed different amounts of melamine {20 (group 1), 40 (group 2), 60 (group 3) or 80 (group 4) g/day/cow} once daily in the morning mixed with a melamine free basal diet for 7-days adaptation followed by 3-days urine and feces sample collections. Melamine was found in all samples tested and its concentration generally increased as dose increased in the diet. These results indicated that different doses of melamine in the diet could result in different concentrations of melamine in milk, plasma, rumen fluid, urine and feces. Data suggested that melamine primarily cleared by urinary excretion, followed by fecal excretion in lactating dairy cows. Mammary tissue was apparently not a major tissue to dispose melamine, especially when fed a relatively low dose (lower than 40 g/day/cow).Key words: Melamine, excretion, lactating dairy cow

    Asymmetric long period fiber gratings fabricated by use of CO₂laser to carve periodic grooves on the optical fiber

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    Author name used in this publication: Peng, Gang-DingAuthor name used in this publication: Wang, Yi-Ping2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Design of arbitrarily shaped planar microstrip antenna arrays with improved efficiency

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    A design technique is described for an arbitrarily shaped planar microstrip antenna array with improved radiation efficiency. In order to fully utilize the limited antenna aperture, several basic modules are proposed from which we construct the array. A consideration of the aperture shape shows that with several practical examples a proper combination of these basic modules not only allows the convenient design of arbitrarily-shaped microstrip array, but also helps to improve the aperture radiation efficiency. To confirm the feasibility of the approach, a circular array with 256 elements was constructed and fabricated. Both computed and measured aperture radiation results are compared and these demonstrate that the design technique is effective for arbitrarily-shaped planar microstrip arrays. © 2013 Sheng Ye et al

    Asymmetric transverse-load characteristics and polarization dependence of long-period fiber gratings written by a focused CO₂ laser

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    Author name used in this publication: Dong Ning WangAuthor name used in this publication: Yunjiang Rao2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    Valley-Polarized Interlayer Conduction of Anisotropic Dirac Fermions in SrMnBi2

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    We report the valley-selective interlayer conduction of SrMnBi2 under in-plane magnetic fields. The c-axis resistivity of SrMnBi2 shows clear angular magnetoresistance oscillations indicating coherent interlayer conduction. Strong fourfold variation of the coherent peak in the c-axis resistivity reveals that the contribution of each Dirac valley is significantly modulated by the in-plane field orientation. This originates from anisotropic Dirac Fermi surfaces with strong disparity in the momentum-dependent interlayer coupling. Furthermore, we found a signature of broken valley symmetry at high magnetic fields. These findings demonstrate that a quasi-two-dimensional anisotropic Dirac system can host a valley-polarized interlayer current through magnetic valley control. © 2014 American Physical Society.open1

    Identification of genes differentially expressed in Jining Grey and Liaoning Cashmere goats ovaries

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    To search for genes controlling high prolificacy of Chinese indigenous goats, differential display reverse transcription-polymerase chain reaction (DDRT-PCR) was used to screen differentially expressed cDNA bands in the sexually matured ovaries of 3-year-old prolific Jining Grey goats and monotocous Liaoning Cashmere goats with 24 combinations of three anchored primers and eight arbitrary primers. 22 expressed sequence tags (ESTs) were proved to be the positive bands by Northern hybridization. They comprised 10 known ESTs and 12 ESTs without homologous sequences in the GenBank. These results indicate that several genes such as GATA-4, metallothionein-like protein, CAT genes and unknown ESTs (CV983340 and CV983341) were expressed only in Jining Grey goats.Keywords: Differential display reverse transcription-polymerase chain reaction, goat, ovary, prolificacyAfrican Journal of Biotechnology Vol. 12(27), pp. 4408-441

    Quantum Oscillation Signatures of Pressure-induced Topological Phase Transition in BiTeI

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    We report the pressure-induced topological quantum phase transition of BiTeI single crystals using Shubnikov-de Haas oscillations of bulk Fermi surfaces. The sizes of the inner and the outer FSs of the Rashba-split bands exhibit opposite pressure dependence up to P=3.35 GPa, indicating pressure-tunable Rashba effect. Above a critical pressure P similar to 2 GPa, the Shubnikov-de Haas frequency for the inner Fermi surface increases unusually with pressure, and the Shubnikov-de Haas oscillations for the outer Fermi surface shows an abrupt phase shift. In comparison with band structure calculations, we find that these unusual behaviors originate from the Fermi surface shape change due to pressure-induced band inversion. These results clearly demonstrate that the topological quantum phase transition is intimately tied to the shape of bulk Fermi surfaces enclosing the time-reversal invariant momenta with band inversion.11117Ysciescopu

    Assessing impacts of climate change and human activities on streamflow and sediment discharge in the Ganjiang River basin (1964-2013)

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    © 2019 by the authors. National large-scale soil and water conservation controls on the Gangjiang River basin have been documented, but the effect of governance on regional watershed hydrology and how the main driving factors act have not been systematically studied yet. To do this, this study evaluated changing trends and detected transition years for both streamflow and sediment discharge using long-term historical records at seven hydrological stations in the Ganjiang River basin over the past 50 years. The double mass curve (DMC) method was used to quantify the effects of both climate change and human activities on hydrological regime shifts. The results showed that the distributions of precipitation, streamflow, and sediment discharge within a year are extremely uneven and mainly concentrated in the flood season of Jiangxi Province. None of the stations showed significant trends over time for either annual precipitation or streamflow, while the annual sediment discharge at most stations decreased significantly over time. The estimation of sediment discharge via DMC indicated that after the transition years, there were rapid reductions in sediment discharge at all hydrological stations, and the average decline degree of midstream and downstream were much larger than that of upstream. Human activities, especially the increase of vegetation cover and construction of large and medium-sized reservoirs, provided a significantly greater contribution to the reduction of sediment discharge than did precipitation changes. As a case study of river evolution under global change environment, this study could provide scientific basis for the control of soil erosion and the management of water resources in Ganjiang River, as well as for the related research of Poyang Lake and the Yangtze River basin of China

    Influence of intermittent water releases on groundwater chemistry at the lower reaches of the Tarim River, China

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    Based on the data of the depths and the chemical properties of groundwater, salinity in the soil profile, and the basic information on each delivery of water collected from the years 2000 to 2006, the varied character of groundwater chemistry and related factors were studied. The results confirmed the three stages of the variations in groundwater chemistry influenced by the intermittent water deliveries. The factors that had close relations to the variations in groundwater chemistry were the distances of monitoring wells from the water channel, the depths of the groundwater, water flux in watercourse, and the salinities in soils. The relations between chemical variation and groundwater depths indicated that the water quality was the best with the groundwater varying from 5 to 6 m. In addition, the constructive species in the study area can survive well with the depth of groundwater varying from 5 to 6 m, so the rational depth of groundwater in the lower reaches of the Tarim River should be 5 m or so. The redistribution of salts in the soil profile and its relations to the chemical properties and depths of groundwater revealed the linear water delivery at present combining with surface water supply in proper sections would promote water quality optimized and speed up the pace of ecological restoration in the study area

    The Mothers and Children’s Environmental Health (MOCEH) study

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    The MOCEH study is a prospective hospital- and community-based cohort study designed to collect information related to environmental exposures (chemical, biological, nutritional, physical, and psychosocial) during pregnancy and childhood and to examine how exposure to environmental pollutants affects growth, development, and disease. The MOCEH network includes one coordinating center, four local centers responsible for recruiting pregnant women, and four evaluation centers (a nutrition center, bio-repository center, neurocognitive development center, and environment assessment center). At the local centers, trained nurses interview the participants to gather information regarding their demographic and socioeconomic characteristics, complications related to the current gestation period, health behaviors and environmental factors. These centers also collect samples of blood, placenta, urine, and breast milk. Environmental hygienists measure each participant’s level of exposure to indoor and outdoor pollutants during the pre- and postnatal periods. The participants are followed up through delivery and until the child is 5 years of age. The MOCEH study plans to recruit 1,500 pregnant women between 2006 and 2010 and to perform follow-up studies on their children. We expect this study to provide evidence to support the hypothesis that the gestational environment has an effect on the development of diseases during adulthood. We also expect the study results to enable evaluation of latency and age-specific susceptibility to exposure to hazardous environmental pollutants, evaluation of growth retardation focused on environmental and genetic risk factors, selection of target environmental diseases in children, development of an environmental health index, and establishment of a national policy for improving the health of pregnant women and their children
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