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Improving top-down proteomics: first steps
Comunicaciones a congreso
Influence of Feeding Enzymatically Hydrolyzed Yeast Cell Wall on Growth Performance and Digestive Function of Feedlot Cattle during Periods of Elevated Ambient Temperature.
In experiment 1, eighty crossbred steers (239±15 kg) were used in a 229-d experiment to evaluate the effects of increasing levels of enzymatically hydrolyzed yeast (EHY) cell wall in diets on growth performance feedlot cattle during periods of elevated ambient temperature. Treatments consisted of steam-flaked corn-based diets supplemented to provide 0, 1, 2, or 3 g EHY/hd/d. There were no effects on growth performance during the initial 139-d period. However, from d 139 to harvest, when 24-h temperature humidity index averaged 80, EHY increased dry matter intake (DMI) (linear effect, p<0.01) and average daily gain (ADG) (linear effect, p = 0.01). There were no treatment effects (p>0.10) on carcass characteristics. In experiment 2, four Holstein steers (292±5 kg) with cannulas in the rumen and proximal duodenum were used in a 4×4 Latin Square design experiment to evaluate treatments effects on characteristics of ruminal and total tract digestion in steers. There were no treatment effects (p>0.10) on ruminal pH, total volatile fatty acid, molar proportions of acetate, butyrate, or estimated methane production. Supplemental EHY decreased ruminal molar proportion of acetate (p = 0.08), increased molar proportion of propionate (p = 0.09), and decreased acetate:propionate molar ratio (p = 0.07) and estimated ruminal methane production (p = 0.09). It is concluded that supplemental EHY may enhance DMI and ADG of feedlot steers during periods of high ambient temperature. Supplemental EHY may also enhance ruminal fiber digestion and decrease ruminal acetate:propionate molar ratios in feedlot steers fed steam-flaked corn-based finishing diets
Effect of adhesive thickness and concrete strength on FRP-Concrete Bonds
The use of fiber-reinforced polymer (FRP) composites for strengthening, repairing, or rehabilitating concrete structures has become more and more popular in the last 10 years. Irrespective of the type of strengthening used, design is conditioned, among others, by concrete-composite bond failure, normally attributed to stress at the interface between these two materials. Single shear, double shear, and notched beam tests are the bond tests most commonly used by the scientific community to estimate bond strength, effective length, and the bond stress-slip relationship. The present paper discusses the effect of concrete strength and adhesive thickness on the results of beam tests, which reproduce debonding conditions around bending cracks much more accurately. The bond stress-slip relationship was analyzed in a cross section near the inner edge, where stress was observed to concentrate. The ultimate load and the bond stress-slip relationship were
visibly affected by concrete strength. Adhesive thickness, in turn, was found to have no significant impact on low-strength concrete but a somewhat greater effect on higher strength materials
Multi-scale accretion in dense cloud cores and the delayed formation of massive stars
The formation mechanism of massive stars remains one of the main open
problems in astrophysics, in particular the relationship between the mass of
the most massive stars, and that of the cores in which they form. Numerical
simulations of the formation and evolution of large molecular clouds, within
which dense cores and stars form self-consistently, show in general that the
cores' masses increase in time, and also that the most massive stars tend to
appear later (by a few to several Myr) than lower-mass stars. Here we present
an idealized model that incorporates accretion onto the cores as well as onto
the stars, in which the core's mass growth is regulated by a ``gravitational
choking'' mechanism that does not involve any form of support. This process is
of purely gravitational origin, and causes some of the mass accreted onto the
core to stagnate there, rather than being transferred to the central stars.
Thus, the simultaneous mass growth of the core and of the stellar mass can be
computed. In addition, we estimate the mass of the most massive allowed star
before its photoionizing radiation is capable of overcoming the accretion flow
onto the core. This model constitutes a proof-of-concept for the simultaneous
growth of the gas reservoir and the stellar mass, the delay in the formation of
massive stars observed in cloud-scale numerical simulations, the need for
massive, dense cores in order to form massive stars, and the observed
correlation between the mass of the most massive star and the mass of the
cluster it resides in. Also, our model implies that by the time massive stars
begin to form in a core, a number of low-mass stars are expected to have
already formed.Comment: Submitted to MNRAS. Originally submitted to Nature Astronomy, but
withdrawn from that journal after not having received a reviewer's report for
over four months. Comments welcom
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