1,386 research outputs found
Effects of a ruminally protected B vitamin supplement on milk yield and composition of lactating dairy cows
It is not clear if B vitamins supplied to the small intestine of dairy cows from dietary and rumen
microbial sources are provided in sufficient quantity to maximize animal performance. Our objective
was to determine effects of adding a ruminally protected B vitamin blend supplement, containing
biotin, folic acid, pantothenic acid and pyridoxine, to the diet of high producing dairy cows on their
productivity. Two dairy facilities located in California (USA) were used, one with mid lactation
Holstein cows (Experiment 1) and the other with early lactation Holstein cows (Experiment 2). In
each Experiment, cows were randomly assigned to treatment in a 2×2 crossover design with 28 d
(Experiment 1) or 35 d (Experiment 2) experimental periods. In Experiment 1, milk and milk fat
yield were unaffected by treatment, although milk fat proportion was lower (37.1 versus 36.3 g/kg;
P<0.01), but milk protein yield was higher (1.21 versus 1.24 kg/d; P=0.02) in cows fed B vitamins.
In Experiment 2, milk (39.60 versus 40.46 kg/d; P=0.02), milk fat (1.40 versus 1.47 kg/d; P<0.01)
and milk protein yield (1.10 versus 1.16 kg/d; P<0.01), as well as milk energy output (113.2 versus
117.8 MJ/d; P<0.01) were all higher with B vitamin feeding. Body condition score (BCS) increasedmore with B vitamin feeding in Experiment 2, but was unaffected in Experiment 1. Body locomotion
score (BLS) increased with B vitamin feeding in both experiments (P=0.01 and < 0.01, respectively),
possibly an indication of reduced locomotory ability.Overall, productivity of high producing lactating
dairy cows responded positively to feeding a mixture of ruminally protected B vitamins, although
differences in the extent of the positive responses between experiments perhaps suggests that early
lactation cows, with lower DM intake to milk yield ratios, may be more responsive to ruminally
protected B vitamins than mid lactation cows, with higher DM intake to milk yield ratios
Nuttier Bubbles
We construct new explicit solutions of general relativity from double
analytic continuations of Taub-NUT spacetimes. This generalizes previous
studies of 4-dimensional nutty bubbles. One 5-dimensional locally
asymptotically AdS solution in particular has a special conformal boundary
structure of . We compute its boundary stress tensor and
relate it to the properties of the dual field theory. Interestingly enough, we
also find consistent 6-dimensional bubble solutions that have only one timelike
direction. The existence of such spacetimes with non-trivial topology is
closely related to the existence of the Taub-NUT(-AdS) solutions with more than
one NUT charge. Finally, we begin an investigation of generating new solutions
from Taub-NUT spacetimes and nuttier bubbles. Using the so-called Hopf duality,
we provide new explicit time-dependent backgrounds in six dimensions.Comment: 32 pages, 1 figure; v.3. typos corrected. Matches the published
versio
Framework for natural resource governance in dryland landscapes in Kenya: Making ecosystem-based management a reality
Cigarette Smoking, Birthweight and Osteoporosis in Adulthood: Results from the Hertfordshire Cohort Study
We looked for interaction between early environment and adult lifestyle in determination of bone mineral content (BMC) and bone mineral density (BMD) among 498 men and 468 women for whom birth records were available. Participants completed a health questionnaire, and bone densitometry (DXA) of the lumbar spine and femoral neck performed
Vortex interaction in patches of randomly placed emergent cylinders
The flow field of multiple-cylinder configurations exhibits complex interactions between shear layers, vortexes and wakes. For high stem-Reynolds numbers, the flow is turbulent and, low and intermediate areal number-densities of cylinders, and turbulence is produced mostly by the work of Reynolds shear stresses in the horizontal plane (uv component) against the time-averaged shear rate characteristic of vertical-axis vortex shedding in the wake of cylinders. The spatial pattern of turbulent production and of other terms of the equation of conservation of Turbulent Kinetic Energy (TKE) is thus mostly determined by the interaction of vortexes shed by individual cylinders and by the distance between cylinders. The main objective of this paper is to advance on the understanding of vortex interaction in patches of randomly placed emergent and rigid cylinders. In particular, the relation between cylinder Strouhal numbers, vortex decay and vortex path statistics is investigated for isolated cylinder and for a cylinder within an array of randomly placed cylinders with a areal-number density of 980 cylinders/m2. Results are compared to shed light on the influence of neighbouring cylinders. An experimental database acquired with 2D Particle Image Velocimetry (PIV) was explored. A methodology to detect vortexes in 2D flow fields is proposed. It features a point-based criterion and a global search to detect all the possible vortex core locations, combined with a curve-based criterion, to decide whether the detected point corresponds to a vortex, depending on the geometry of streamlines. The results show a decrease on the amount of vortexes and a shorter vortex life for the cylinder within the array when compared with the isolated cylinder. The averaged vortex path is also affected by the presence of neighbouring cylinders. Concerning the Strouhal number, the normalized shedding frequency is approximately the same for both studied cases
Distribution and drivers of marine isoprene concentration across the Southern Ocean
© 2020 by the authors.
Isoprene is a biogenic trace gas produced by terrestrial vegetation and marine phytoplankton. In the remote oceans, where secondary aerosols are mostly biogenic, marine isoprene emissions affect atmospheric chemistry and influence cloud formation and brightness. Here, we present the first compilation of new and published measurements of isoprene concentrations in the Southern Ocean and explore their distribution patterns. Surface ocean isoprene concentrations in November through April span 1 to 94 pM. A band of higher concentrations is observed around a latitude of ≈40° S and a surface sea temperature of 15 °C. High isoprene also occurs in high productivity waters near islands and continental coasts. We use concurrent measurements of physical, chemical, and biological variables to explore the main potential drivers of isoprene concentration by means of paired regressions and multivariate analysis. Isoprene is best explained by phytoplankton-related variables like the concentrations of chlorophyll-a, photoprotective pigments and particulate organic matter, photosynthetic efficiency (influenced by iron availability), and the chlorophyll-a shares of most phytoplankton groups, and not by macronutrients or bacterial abundance. A simple statistical model based on chlorophyll-a concentration and a sea surface temperature discontinuity accounts for half of the variance of isoprene concentrations in surface waters of the Southern Ocean
On zero-point energy, stability and Hagedorn behavior of Type IIB strings on pp-waves
Type IIB strings on many pp-wave backgrounds, supported either by 5-form or
3-form fluxes, have negative light-cone zero-point energy. This raises the
question of their stability and poses possible problems in the definition of
their thermodynamic properties. After having pointed out the correct way of
calculating the zero-point energy, an issue not fully discussed in literature,
we show that these Type IIB strings are classically stable and have well
defined thermal properties, exhibiting a Hagedorn behavior.Comment: Latex, 13 pages. v2: regularization/renormalization prescription
clarified, refs. adde
Stratified glucocorticoid monotherapy is safe and effective for most cases of giant cell arteritis
Funding: We are grateful to Versus Arthritis (grant 12159) for supporting our work.Peer reviewedPublisher PD
Nanobody-targeted photodynamic therapy induces significant tumor regression of trastuzumab-resistant HER2-positive breast cancer, after a single treatment session
Rationale: A substantial number of breast cancer patients with an overexpression of the human epidermal growth factor receptor 2 (HER2) have residual disease after neoadjuvant therapy or become resistant to trastuzumab. Photodynamic therapy (PDT) using nanobodies targeted to HER2 is a promising treatment option for these patients. Here we investigate the in vitro and in vivo antitumor efficacy of HER2-targeted nanobody-photosensitizer (PS) conjugate PDT. Methods: Nanobodies targeting HER2 were obtained from phage display selections. Monovalent nanobodies were engineered into a biparatopic construct. The specificity of selected nanobodies was tested in immunofluorescence assays and their affinity was evaluated in binding studies, both performed in a panel of breast cancer cells varying in HER2 expression levels. The selected HER2-targeted nanobodies 1D5 and 1D5-18A12 were conjugated to the photosensitizer IRDye700DX and tested in in vitro PDT assays. Mice bearing orthotopic HCC1954 trastuzumab-resistant tumors with high HER2 expression or MCF-7 tumors with low HER2 expression were intravenously injected with nanobody-PS conjugates. Quantitative fluorescence spectroscopy was performed for the determination of the local pharmacokinetics of the fluorescence conjugates. After nanobody-PS administration, tumors were illuminated to a fluence of 100 J∙cm-2, with a fluence rate of 50 mW∙cm-2, and thereafter tumor growth was measured with a follow-up until 30 days. Results: The selected nanobodies remained functional after conjugation to the PS, binding specifically and with high affinity to HER2-positive cells. Both nanobody-PS conjugates potently and selectively induced cell death of HER2 overexpressing cells, either sensitive or resistant to trastuzumab, with low nanomolar LD50 values. In vivo, quantitative fluorescence spectroscopy showed specific accumulation of nanobody-PS conjugates in HCC1954 tumors and indicated 2 h post injection as the most suitable time point to apply light. Nanobody-targeted PDT with 1D5-PS and 1D5-18A12-PS induced significant tumor regression of trastuzumab-resistant high HER2 expressing tumors, whereas in low HER2 expressing tumors only a slight growth delay was observed. Conclusion: Nanobody-PS conjugates accumulated selectively in vivo and their fluorescence could be detected through optical imaging. Upon illumination, they selectively induced significant tumor regression of HER2 overexpressing tumors with a single treatment session. Nanobody-targeted PDT is therefore suggested as a new additional treatment for HER2-positive breast cancer, particularly of interest for trastuzumab-resistant HER2-positive breast cancer. Further studies are now needed to assess the value of this approach in c
Emotional valence and arousal affect reading in an interactive way: neuroimaging evidence for an approach-withdrawal framework
A growing body of literature shows that the emotional content of verbal material affects reading, wherein emotional words are given processing priority compared to neutral words. Human emotions can be conceptualised within a two-dimensional model comprised of emotional valence and arousal (intensity). These variables are at least in part distinct, but recent studies report interactive effects during implicit emotion processing and relate these to stimulus-evoked approach-withdrawal tendencies. The aim of the present study was to explore how valence and arousal interact at the neural level, during implicit emotion word processing. The emotional attributes of written word stimuli were orthogonally manipulated based on behavioural ratings from a corpus of emotion words. Stimuli were presented during an fMRI experiment while 16 participants performed a lexical decision task, which did not require explicit evaluation of a word's emotional content. Results showed greater neural activation within right insular cortex in response to stimuli evoking conflicting approach-withdrawal tendencies (i.e., positive high-arousal and negative low-arousal words) compared to stimuli evoking congruent approach vs. withdrawal tendencies (i.e., positive low-arousal and negative high-arousal words). Further, a significant cluster of activation in the left extra-striate cortex was found in response to emotional than neutral words, suggesting enhanced perceptual processing of emotionally salient stimuli. These findings support an interactive two-dimensional approach to the study of emotion word recognition and suggest that the integration of valence and arousal dimensions recruits a brain region associated with interoception, emotional awareness and sympathetic functions
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