106 research outputs found

    Dietary supplementation of essential oils in dairy cows: evidence for stimulatory effects on nutrient absorption

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    Results of recent in vitro experiments suggest that essential oils (EO) may not only influence ruminal fermentation but also modulate the absorption of cations like Na+, Ca2+ and NH4+ across ruminal epithelia of cattle and sheep through direct interaction with epithelial transport proteins, such as those of the transient receptor potential family. The aim of the current study was to examine this hypothesis by testing the effect of a blend of essential oils (BEO) on cation status and feed efficiency in lactating dairy cows. In the experiment, 72 dairy cows in mid-to-end lactation were divided into two groups of 36 animals each and fed the same mixed ration with or without addition of BEO in a 2×2 cross-over design. Feed intake, milk yield and composition, plasma and urine samples were monitored. Feeding BEO elevated milk yield, milk fat and protein yield as well as feed efficiency, whereas urea levels in plasma and milk decreased. In addition, plasma calcium levels increased significantly upon BEO supplementation, supporting the hypothesis that enhanced cation absorption might contribute to the beneficial effects of these EO

    Participatory Geographic Information Systems as an Organizational Platform for the Integration of Traditional and Scientific Knowledge in Contemporary Fire and Fuels Management

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    Traditional knowledge about fire and its effects held by indigenous people, who are connected to specific landscapes, holds promise for informing contemporary fire and fuels management strategies and augmenting knowledge and information derived from western science. In practice, however, inadequate means to organize and communicate this traditional knowledge with scientists and managers can limit its consideration in decisions, requiring novel approaches to interdisciplinary and cross-cultural communication and collaboration. We propose that Participatory Geographic Information Systems (PGIS) is one platform for the assemblage and communication of traditional knowledge vital to fire and fuels management, while preserving linkages to broader cultural contexts. We provide summaries of four preliminary case studies in the Intermountain West of North America to illustrate different potential applications of a PGIS tool in this context and describe some remaining challenges. Management and Policy Implications: Participatory Geographic Information Systems (PGIS) can offer a powerful approach for enhancing current decisionmaking by allowing for the integration of traditional and scientific knowledge systems with spatial environmental data in an interactive participatory process. Integrated data sets can allow traditional and scientific knowledge experts to share, explore, manage, analyze, and interpret multidimensional data in a common spatial context to develop more informed management decisions. Such combined data sets could provide a more comprehensive assessment of fire-related ecological change than is currently used in decisionmaking and enhance inclusion of effects on local resource utility values and areas of cultural significance. The use of a PGIS interface creates opportunities for traditional knowledge holders to share information and potential prescriptions while maintaining confidentiality. Knowledge integration efforts using PGIS as an organizational tool would help to bridge the communication gap that commonly exists between scientists, managers, and traditional knowledge holders as ecosystems continue to be altered through processes of land management and climate change

    Representations of spectral coordinates in FITS

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    Greisen & Calabretta describe a generalized method for specifying the coordinates of FITS data samples. Following that general method, Calabretta & Greisen describe detailed conventions for defining celestial coordinates as they are projected onto a two-dimensional plane. The present paper extends the discussion to the spectral coordinates of wavelength, frequency, and velocity. World coordinate functions are defined for spectral axes sampled linearly in wavelength, frequency, or velocity, linearly in the logarithm of wavelength or frequency, as projected by ideal dispersing elements, and as specified by a lookup table.Comment: 25 pages, 5 figure

    The First Extrasolar Planet Discovered with a New Generation High Throughput Doppler Instrument

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    We report the detection of the first extrasolar planet, ET-1 (HD 102195b), using the Exoplanet Tracker (ET), a new generation Doppler instrument. The planet orbits HD 102195, a young star with solar metallicity that may be part of the local association. The planet imparts radial velocity variability to the star with a semiamplitude of 63.4±2.063.4\pm2.0 m s1^{-1} and a period of 4.11 days. The planetary minimum mass (msinim \sin i) is 0.488±0.0150.488\pm0.015 MJM_J.Comment: 42 pages, 11 figures and 5 tables, Accepted for publication in Ap

    Pulsational Mapping of Calcium Across the Surface of a White Dwarf

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    We constrain the distribution of calcium across the surface of the white dwarf star G29-38 by combining time series spectroscopy from Gemini-North with global time series photometry from the Whole Earth Telescope. G29-38 is actively accreting metals from a known debris disk. Since the metals sink significantly faster than they mix across the surface, any inhomogeneity in the accretion process will appear as an inhomogeneity of the metals on the surface of the star. We measure the flux amplitudes and the calcium equivalent width amplitudes for two large pulsations excited on G29-38 in 2008. The ratio of these amplitudes best fits a model for polar accretion of calcium and rules out equatorial accretion.Comment: Accepted to the Astrophysical Journal. 16 pages, 10 figures

    Cyclical period changes in the dwarf novae V2051 Oph and V4140 Sgr

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    We report the identification of cyclical changes in the orbital period of the eclipsing dwarf novae V2051 Ophiuchi and V4140 Sagitarii. We used sets of white dwarf mid-eclipse timings to construct observed-minus-calculated diagrams covering, respectively, 25 and 16 years of observations. The V2051 Oph data present cyclical variations that can be fitted by a linear plus sinusoidal function with period 22 +/- 2 yr and amplitude 17 +/- 3 s. The statistical significance of this period by an F-test is larger than 99.9 per cent. The V4140 Sgr data present cyclical variations of similar amplitude and period 6.9 +/- 0.3 yr which are statistically significant at the 99.7 per cent level. We derive upper limits for secular period changes of |dP/dt| < 3x10^{-12} and |dP/dt| < 1.8x10^{-11}, respectively for V2051 Oph and V4140 Sgr. We combined our results with those in the literature to construct a diagram of the amplitude versus period of the modulation for a sample of 11 eclipsing cataclysmic variables (CVs). If the cyclical period changes are the consequence of a solar-type magnetic activity cycle in the secondary star, then magnetic activity is a widespread phenomenon in CVs, being equally common among long- and short-period systems. This gives independent evidence that the magnetic field (and activity) of the secondary stars of CVs do not disappear when they become fully convective. We also find that the fractional cycle period changes of the short-period CVs are systematically smaller than those of the long-period CVs.Comment: 9 pages, 4 postscript figures, coded with MNRAS latex style file. To appear in Monthly Notices of the Royal Astronomical Societ

    Microtubule sliding activity of a kinesin-8 promotes spindle assembly and spindle length control

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    Molecular motors play critical roles in the formation of mitotic spindles, either through controlling the stability of individual microtubules, or by cross-linking and sliding microtubule arrays. Kinesin-8 motors are best known for their regulatory roles in controlling microtubule dynamics. They contain microtubule-destabilizing activities, and restrict spindle length in a wide variety of cell types and organisms. Here, we report for the first time on an anti-parallel microtubule-sliding activity of the budding yeast kinesin-8, Kip3. The in vivo importance of this sliding activity was established through the identification of complementary Kip3 mutants that separate the sliding activity and microtubule destabilizing activity. In conjunction with kinesin-5/Cin8, the sliding activity of Kip3 promotes bipolar spindle assembly and the maintenance of genome stability. We propose a “slide-disassemble” model where Kip3’s sliding and destabilizing activity balance during pre-anaphase. This facilitates normal spindle assembly. However, Kip3’s destabilizing activity dominates in late anaphase, inhibiting spindle elongation and ultimately promoting spindle disassembly

    A measurement by BOOMERANG of multiple peaks in the angular power spectrum of the cosmic microwave background

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    This paper presents a measurement of the angular power spectrum of the Cosmic Microwave Background from l=75 to l=1025 (~10' to 5 degrees) from a combined analysis of four 150 GHz channels in the BOOMERANG experiment. The spectrum contains multiple peaks and minima, as predicted by standard adiabatic-inflationary models in which the primordial plasma undergoes acoustic oscillations. These results significantly constrain the values of Omega_tot, Omega_b h^2, Omega_c h^2 and n_s.Comment: changes to reflect version accepted by Ap

    Association and Haplotype Analyses of Positional Candidate Genes in Five Genomic Regions Linked to Scrotal Hernia in Commercial Pig Lines

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    Scrotal hernia in pigs is a complex trait likely affected by genetic and environmental factors. A large-scale association analysis of positional and functional candidate genes was conducted in four previously identified genomic regions linked to hernia susceptibility on Sus scrofa chromosomes 2 and 12, as well as the fifth region around 67 cM on chromosome 2, respectively. In total, 151 out of 416 SNPs discovered were genotyped successfully. Using a family-based analysis we found that four regions surrounding ELF5, KIF18A, COL23A1 on chromosome 2, and NPTX1 on chromosome 12, respectively, may contain the genetic variants important for the development of the scrotal hernia in pigs. These findings were replicated in another case-control dataset. The SNPs around the ELF5 region were in high linkage disequilibrium with each other, and a haplotype containing SNPs from ELF5 and CAT was highly significantly associated with hernia development. Extensive re-sequencing work focused on the KIF18A gene did not detect any further SNPs with extensive association signals. These genes may be involved in the estrogen receptor signaling pathway (KIF18A and NPTX1), the epithelial-mesenchymal transition (ELF5) and the collagen metabolism pathway (COL23A1), which are associated with the important molecular characteristics of hernia pathophysiology. Further investigation on the molecular mechanisms of these genes may provide more molecular clues on hernia development in pigs
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