4,297 research outputs found

    Potentials to differentiate milk composition by different feeding strategies

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    To investigate the effect of the dietary intake of the cow on milk composition, bulk-tank milk was collected on 5 occasions from conventional (n = 15) and organic (n = 10) farms in Denmark and on 4 occasions from low-input nonorganic farms in the United Kingdom, along with management and production parameters. Production of milk based on feeding a high intake of cereals, pasture, and grass silage resulted in milk with a high concentration of α-linolenic acid (9.4 ± 0.2 mg/ kg of fatty acids), polyunsaturated fatty acids (3.66 ± 0.07 mg/kg of fatty acids), and natural stereoisomer of α-tocopherol (RRR-α-tocopherol, 18.6 ± 0.5 mg/kg of milk fat). A milk production system using a high proportion of maize silage, by-products, and commercial concentrate mix was associated with milk with high concentrations of linoleic acid (LA; 19.7 ± 0.4 g/kg of fatty acids), monounsaturated fatty acids (27.5 ± 0.3 mg/kg of fatty acids), and a high ratio between LA and α-linolenic acid (4.7 ± 0.2). Comparing these 2 production systems with a very extensive nonorganic milk production system relying on pasture as almost the sole feed (95 ± 4% dry matter intake), it was found that the concentrations of conjugated LA (cis-9,trans-11; 17.5 ± 0.7 g/kg of fatty acids), trans-11-vaccenic acid (37 ± 2 g/kg of fatty acids), and monounsaturated fatty acids (30.4 ± 0.6 g/kg of fatty acids) were higher in the extensively produced milk together with the concentration of antioxidants; total α-tocopherol (32.0 ± 0.8 mg/kg of milk fat), RRR-α-tocopherol (30.2 ± 0.8 mg/kg of milk fat), and β-carotene (9.3 ± 0.5 mg/kg of milk fat) compared with the organic and conventional milk. Moreover, the concentration of LA (9.2 ± 0.7 g/kg of fatty acids) in milk from the extensive milk production system was found to approach the recommended unity ratio between n-6 and n-3, although extensive milk production also resulted in a lower daily milk yield

    Hvordan kan økologisk jordbrug være med til at styrke vækst og udvikling i landdistrikterne?

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    Øget økologisk jordbrug kan, hvis omlægningen designes rigtigt, bidrage til udviklingen i landdistrikterne. Dette belyses med en række eksempler. En kortlægning af økologisk jordbrugs udbredelse i Danmark viser, at de områder, hvor der i dag er meget økologisk jordbrug, i vid udstrækning er sammenfaldende med de områder, hvor der er et særligt behov for udvikling i landdistrikterne. Det er således et vigtigt at belyse, hvorledes den økologiske jordbrugsproduktion bedst tilrettelægges, så den bidrager til landdistriktsudviklingen i disse områder

    Sensory quality of organic milk based on grazing and high ratio of legumes in the feeding ration

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    Organic milk forms an important segment of the fresh milk production in Denmark. However, studies are needed to substantiate the high quality and future development of new variations of organic milk for different consumers. Differences in the composition of organically and conventionally produced milk (free fatty acids and a higher content of antioxidants in organic milk) are suggested to be a result of differences in feeding regimes (maize components in conventional production vs. grass and legumes in organic production). Also, milk from dairy cows fed grass silage has a different flavour compared to milk from dairy cows fed maize silage. This study evaluated the sensory properties of organic milk from dairy cows from different feeding trials. The effect of four different legumes and herbs, lucerne (Medicargo sativa), red clover (Trifolium pratense), white clover (Trifolium repens) and chicory (Cichorium intybus), was studied following a schedule including 4*12 Holstein Frisian cows. Descriptive sensory analysis was performed on the fresh pasteurized unhomogenized full-fat milk (6 replicates in 2 sessions) with a trained panel of 10 assessors. The preliminary results from the descriptive analysis of summer feeding (grazing) and winter feeding (silage) show that feeding with legumes and grass affects the sensory quality of full-fat unhomogenized organic milk. The most distinct milk was obtained from feeding ration high in chicory. This milk was characterized by a bitter and metallic taste and an astringent aftertaste both from the summer grazing and winter silage feeding trials. Red clover was characterized by a boiled milk flavour (summer), lucerne by a fatty aftertaste (winter) and white clover by a sweet and creamy flavour (winter). The results of the first season, which will also include relations between the sensory quality and the milk composition, serve as important inputs for the extensive studies to be conducted during the next three seasons. These studies include farm studies and consumer studies (product information, preference and purchase motives)

    Growth and carcass quality of grazing Holstein bulls and Limousine x Holstein bulls and heifers slaughtered at 17 months of age

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    Across sexes, crossbreeding did not improve growth rate compared to HOL bulls Crossbreeding markedly improved conformation Heifers produced carcasses of acceptable fatness Fatness and lean/fat colour of pasture-fed bulls were not acceptabl

    [OI]63micron jets in class 0 sources detected by Herschel

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    We present Herschel PACS mapping observations of the [OI]63 micron line towards protostellar outflows in the L1448, NGC1333-IRAS4, HH46, BHR71 and VLA1623 star forming regions. We detect emission spatially resolved along the outflow direction, which can be associated with a low excitation atomic jet. In the L1448-C, HH46 IRS and BHR71 IRS1 outflows this emission is kinematically resolved into blue- and red-shifted jet lobes, having radial velocities up to 200 km/s. In the L1448-C atomic jet the velocity increases with the distance from the protostar, similarly to what observed in the SiO jet associated with this source. This suggests that [OI] and molecular gas are kinematically connected and that this latter could represent the colder cocoon of a jet at higher excitation. Mass flux rates (\.Mjet_{jet}(OI)) have been measured from the [OI]63micron luminosity adopting two independent methods. We find values in the range 1-4 107^{-7} Mo/yr for all sources but HH46, for which an order of magnitude higher value is estimated. \.Mjet_{jet}(OI) are compared with mass accretion rates (\.Macc_{acc}) onto the protostar and with \.Mjet_{jet} derived from ground-based CO observations. \.Mjet_{jet}(OI)/\.Macc_{acc} ratios are in the range 0.05-0.5, similar to the values for more evolved sources. \.Mjet_{jet}(OI) in HH46 IRS and IRAS4A are comparable to \.Mjet_{jet}(CO), while those of the remaining sources are significantly lower than the corresponding \.Mjet_{jet}(CO). We speculate that for these three sources most of the mass flux is carried out by a molecular jet, while the warm atomic gas does not significantly contribute to the dynamics of the system.Comment: 37 pages and 12 figures, accepted for publication on Astrophysical Journa

    Entanglement-enhanced quantum rectification

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    Quantum mechanics dictates the band-structure of materials that is essential for functional electronic components. With increased miniaturization of devices it becomes possible to exploit the full potential of quantum mechanics through the principles of superpositions and entanglement. We propose a new class of quantum rectifiers that can leverage entanglement to dramatically increase performance by coupling two small spin chains through an effective double-slit interface. Simulations show that rectification is enhanced by several orders of magnitude even in small systems and should be realizable using several of the quantum technology platforms currently available.Comment: 5+15 pages, 3+6 figure

    Bias and temperature dependence of the 0.7 conductance anomaly in Quantum Point Contacts

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    The 0.7 (2e^2/h) conductance anomaly is studied in strongly confined, etched GaAs/GaAlAs quantum point contacts, by measuring the differential conductance as a function of source-drain and gate bias as well as a function of temperature. We investigate in detail how, for a given gate voltage, the differential conductance depends on the finite bias voltage and find a so-called self-gating effect, which we correct for. The 0.7 anomaly at zero bias is found to evolve smoothly into a conductance plateau at 0.85 (2e^2/h) at finite bias. Varying the gate voltage the transition between the 1.0 and the 0.85 (2e^2/h) plateaus occurs for definite bias voltages, which defines a gate voltage dependent energy difference Δ\Delta. This energy difference is compared with the activation temperature T_a extracted from the experimentally observed activated behavior of the 0.7 anomaly at low bias. We find \Delta = k_B T_a which lends support to the idea that the conductance anomaly is due to transmission through two conduction channels, of which the one with its subband edge \Delta below the chemical potential becomes thermally depopulated as the temperature is increased.Comment: 9 pages (RevTex) with 9 figures (some in low resolution

    Inventaire des mollusques d'eau douce en Ituri (Haut-Zaïre) : conséquences sanitaires pour l'homme et le bétail

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    Cent soixante-dix points d'abreuvement pour le bétail ont été prospectés de juin 1986 à août 1988 en Ituri (nord-est du Zaïre) afin de déterminer les principaux mollusques d'eau douce pouvant intervenir dans la transmission des trématodoses animales et humaines. Dix-neuf espèces de gastéropodes ont été rencensées. Quatre gîtes sur dix n'hébergent pas ou très peu de mollusques. Les trois espèces les plus fréquemment rencontrées sont #Lymnaea natalensis, #Biomphalaria pfeifferi(27,6 (27,6 %) et #Bulinus africanus (15,3 %). La distribution des deux premières espèces semble très homogène au niveau régional et ne permet pas l'établissement d'une relation avec le risque parasitaire (#Fasciola gigantica et #Schistosoma mansoni). Inversement, la répartition de #Bulinus africanus (et secondairement celle de #B. forskalii) correspond globalement à la distribution de #Schistosoma bovis chez les bovins. L'association de #Lymnaea natalensis et de #Bulinus africanus au sein des gîtes rend compte de l'association des infestations à #Fasciola gigantica et #Schistosoma bovis$ chez les bovins. (Résumé d'auteur

    Water distribution in shocked regions of the NGC1333-IRAS4A protostellar outflow

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    We present the study of the H2O spatial distribution at two bright shocked regions along IRAS4A, one of the strongest H2O emitters among the Class 0 outflows. We obtained Herschel-PACS maps of the IRAS4A outflow and HIFI observations of two shocked positions. The largest HIFI beam of 38 arcsec at 557 GHz was mapped in several key water lines with different upper energy levels, to reveal possible spatial variations of the line profiles. We detect four H2O lines and CO (16-15) at the two selected positions. In addition, transitions from related outflow and envelope tracers are detected. Different gas components associated with the shock are identified in the H2O emission. In particular, at the head of the red lobe of the outflow, two distinct gas components with different excitation conditions are distinguished in the HIFI emission maps: a compact component, detected in the ground-state water lines, and a more extended one. Assuming that these two components correspond to two different temperature components observed in previous H2O and CO studies, the excitation analysis of the H2O emission suggests that the compact (about 3 arcsec) component is associated with a hot (T~1000 K) gas with densities ~(1-4)x10^5 cm^{-3}, whereas the extended one (10-17 arcsec) traces a warm (T~300-500 K) and dense gas (~(3-5)x10^7 cm^{-3}). Finally, using the CO (16-15) emission observed at R2, we estimate the H2O/H2 abundance of the warm and hot components to be (7-10)x10^{-7} and (3-7)x10^{-5}. Our data allowed us, for the first time, to resolve spatially the two temperature components previously observed with HIFI and PACS. We propose that the compact hot component may be associated with the jet that impacts the surrounding material, whereas the warm, dense, and extended component originates from the compression of the ambient gas by the propagating flow.Comment: 13 pages, 11 figures. Accepted for publication in Astronomy and Astrophysic
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