106 research outputs found
Dietary supplementation of essential oils in dairy cows: evidence for stimulatory effects on nutrient absorption
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
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
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
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 m s and a period of 4.11 days.
The planetary minimum mass () is .Comment: 42 pages, 11 figures and 5 tables, Accepted for publication in Ap
Pulsational Mapping of Calcium Across the Surface of a White Dwarf
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
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
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
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
The BOOMERanG experiment and the curvature of the Universe
We describe the BOOMERanG experiment and its main result, i.e. the
measurement of the large scale curvature of the Universe. BOOMERanG is a
balloon-borne microwave telescope with sensitive cryogenic detectors. BOOMERanG
has measured the angular distribution of the Cosmic Microwave Background on
of the sky, with a resolution of arcmin and a sensitivity
of per pixel. The resulting image is dominated by hot and cold
spots with rms fluctuations and typical size of . The
detailed angular power spectrum of the image features three peaks and two dips
at and , respectively. Such very characteristic
spectrum can be explained assuming that the detected structures are the result
of acoustic oscillations in the primeval plasma. In this framework, the
measured pattern constrains the density parameter to be (95% confidence interval). Other cosmological parameters, like the
spectral index of initial density fluctuations, the density parameter for
baryons, dark matter and dark energy, are detected or constrained by the
BOOMERanG measurements and by other recent CMB anisotropy experiments. When
combined with other cosmological observations, these results depict a new,
consistent, cosmological scenario.Comment: Proc. of the Erice School on "Neutrinos in Astro, Particle and
Nuclear Physics", 18.-26. September 2001, Amand Faessler, Jan Kuckei eds,
"Progress in Particle and Nuclear Physics", vol. 4
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