229 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
A Planetary Mass Companion to the K0 Giant HD 17092
We report the discovery of a substellar-mass companion to the K0-giant HD
17092 with the Hobby-Eberly Telescope. In the absence of any correlation of the
observed 360-day periodicity with the standard indicators of stellar activity,
the observed radial velocity variations are most plausibly explained in terms
of a Keplerian motion of a planetary-mass body around the star. With the
estimated stellar mass of 2.3Msun, the minimum mass of the planet is 4.6MJ. The
planet's orbit is characterized by a mild eccentricity of e=0.17 and a
semi-major axis of 1.3 AU. This is the tenth published detection of a planetary
companion around a red giant star. Such discoveries add to our understanding of
planet formation around intermediate-mass stars and they provide dynamical
information on the evolution of planetary systems around post-main sequence
stars.Comment: 13 pages, 3 figures, 2 tables. Submitted to Ap
Impact of Increasing Dietary Calcium Levels on Calcium Excretion and Vitamin D Metabolites in the Blood of Healthy Adult Cats
Background Dietary calcium (Ca) concentrations might affect regulatory
pathways within the Ca and vitamin D metabolism and consequently excretory
mechanisms. Considering large variations in Ca concentrations of feline diets,
the physiological impact on Ca homeostasis has not been evaluated to date. In
the present study, diets with increasing concentrations of dicalcium phosphate
were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02,
7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each
feeding period was divided into a 10-day adaptation and an 8-day sampling
period in order to collect urine and faeces. On the last day of each feeding
period, blood samples were taken. Results Urinary Ca concentrations remained
unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing
dietary Ca levels. No effect on whole and intact parathyroid hormone levels,
fibroblast growth factor 23 and calcitriol concentrations in the blood of the
cats were observed. However, the calcitriol precursors 25(OH)D2 and 25(OH)D3,
which are considered the most useful indicators for the vitamin D status,
decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing
dietary levels of dicalcium phosphate revealed an acidifying effect on urinary
fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by
an increase of urinary phosphorus (P) concentrations (P < 0.001). Conclusions
In conclusion, calcitriol precursors were linearly affected by increasing
dietary Ca concentrations. The increase in faecal Ca excretion indicates that
Ca homeostasis of cats is mainly regulated in the intestine and not by the
kidneys. Long-term studies should investigate the physiological relevance of
the acidifying effect observed when feeding diets high in Ca and P
Fortnightly Fluctuations in the O-C Diagram of CS 1246
Dominated by a single, large-amplitude pulsation mode, the rapidly-pulsating
hot subdwarf B star CS 1246 is a prime candidate for a long-term O-C diagram
study. We collected nearly 400 hours of photometry with the PROMPT telescopes
over a time span of 14 months to begin looking for secular variations in the
pulse timings. Interestingly, the O-C diagram is dominated by a strong
sinusoidal pattern with a period of 14.1 days and an amplitude of 10.7
light-seconds. Underneath this sine wave is a secular trend implying a decrease
in the 371.7-s pulsational period of Pdot = -1.9 x 10^-11, which we attribute
to the evolution of the star through the H-R diagram. The sinusoidal variation
could be produced by the presence of a low-mass companion, with m sin i ~ 0.12
Msun, orbiting the subdwarf B star at a distance of 20 Rsun. An analysis of the
combined light curve reveals the presence of a low-amplitude first harmonic to
the main pulsation mode.Comment: Accepted for publication in MNRAS. 11 pages, 8 figures, 5 table
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
Prime movers : mechanochemistry of mitotic kinesins
Mitotic spindles are self-organizing protein machines that harness teams of multiple force generators to drive chromosome segregation. Kinesins are key members of these force-generating teams. Different kinesins walk directionally along dynamic microtubules, anchor, crosslink, align and sort microtubules into polarized bundles, and influence microtubule dynamics by interacting with microtubule tips. The mechanochemical mechanisms of these kinesins are specialized to enable each type to make a specific contribution to spindle self-organization and chromosome segregation
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
Streamlining Library Classes: Scheduling, marketing, and data gathering in order to increase the value of a library service
Presented at the 2020 Medical Library Association Virtual Conference
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
Reporting of Sex Specific Outcomes in High Impact Orthopedic Journals
Background: There are known biologic differences between men and women that affect all aspects of health and disease, including in orthopedics. Hormonal regulation influences bone density, tissue structure, joint laxity, and muscle mass. Differences in anatomy and neuromuscular control have also been identified. While previous studies on disease incidences have shown certain conditions are more common in one sex (e.g., osteoarthritis in women), it is not routine practice to evaluate or publish outcomes based on sex.
Objectives: To evaluate the frequency with which papers in orthopedic journals published sex-specific outcomes with regard to knee osteoarthritis and rotator cuff pathology.
Methods: Four high-impact orthopedic journals were reviewed: Journal of Bone and Joint Surgery (JBJS), Clinical Orthopedics and Related Research (CORR), American Journal of Sports Medicine (AJSM), and Journal of Arthroplasty (JOA). JBJS and CORR were reviewed for rotator cuff and knee osteoarthritis. AJSM was reviewed for rotator cuff, while JOA was reviewed for knee osteoarthritis. 100 articles from each journal were reviewed. If there was any further analysis of sex beyond the statement of how many men and women were included in each group, a study was designated as successfully reporting sexspecific outcomes.
Results: 24-29% of rotator cuff articles reported on sex-specific outcomes. Sex specific outcomes were reported in 32-40% of knee osteoarthritis publications. Comparing rotator cuff to knee osteoarthritis articles, there was a trend toward more publications with sex-specific outcomes in knee osteoarthritis, however, this was not statistically significant (p = 0.0562). JBJS publishes significantly more articles reporting sex specific outcomes regarding knee osteoarthritis than rotator cuff (p= 0.0156).
Conclusions: Sex-specific outcomes are not widely reported in high-impact orthopedic journals. Sexspecific outcomes are reported more often in knee osteoarthritis where there are already well-known sexbased differences. To improve care, sex-specific outcomes should be reported across all orthopedic conditions.https://jdc.jefferson.edu/sexandgenderhealth/1028/thumbnail.jp
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