Dietary starch concentration alters reticular pH, hepatic copper concentration, and performance in lactating Holstein-Friesian dairy cows receiving added dietary sulfur and molybdenum

To test the hypothesis that Cu metabolism in dairy cows is affected by dietary starch concentration and additional sulfur S and Mo, 60 Holstein-Friesian dairy cows that were [mean ± standard error (SE)] 33 ± 2.5 days postcalving and yielding 41 ± 0.9 kg of milk/d were fed 1 of 4 diets in a 2 × 2 factorial design experiment over a 14-wk period. The 4 diets had a Cu concentration of approximately 15 mg/kg of dry matter (DM), a grass silage-to-corn silage ratio of 1:1, a dietary starch concentration of either 150 g/kg of DM (low starch, LS) or 220 g/kg of DM (high starch, HS), and were either unsupplemented (−) or supplemented (+) with an additional 0.8 g of S/kg of DM and 4.4 mg of Mo/kg of DM. We found an effect of dietary starch concentration on mean reticular pH, which was 0.15 pH units lower in cows fed the high starch diets. The addition of S and Mo decreased intake by 1.8 kg of DM/d, an effect that was evident beginning in wk 1 of the study. Mean milk and fat yields were 37.0 and 1.51 kg/d, respectively, and were not affected by dietary treatment. We found an effect of dietary starch concentration on milk protein concentration, protein yield, and urea nitrogen, which were increased by 2.8 g/kg, 0.09 kg/d, and 2.1 mg/dL, respectively, in cows fed the high starch diets. We found no effect of dietary treatment on either cow live weight or body condition. Mean plasma Cu, Fe, and Zn concentrations were 15.3, 42.1, and 14.4 µmol/L, respectively, and were not affected by dietary treatment. In contrast, we found an interaction between dietary starch concentration and Cu antagonists on plasma Mo, where feeding additional S and Mo increased plasma Mo to a greater extent when cows were offered the high versus low starch diet. We also found that increasing dietary starch concentration increased serum ceruloplasmin activity, but serum haptoglobin concentration was not affected by dietary treatment. The addition of S and Mo decreased hepatic Cu concentration, whereas in cows fed the higher dietary starch concentration, hepatic Cu concentration was increased over the period of our study. We concluded that increasing dietary starch concentration decreases rumen pH and increases milk protein yield and hepatic Cu concentration, whereas feeding additional S and Mo decreases intake and hepatic Cu concentration

Contention Resolution with Heterogeneous Job Sizes

Abstract. We study the problem of contention resolution for differentsized jobs on a simple channel. When a job makes a run attempt, it learns only whether the attempt succeeded or failed. We first analyze binary exponential backoff, and show that it achieves a makespan of V2 Θ( logn) with high probability, where V is the total work of all n contending jobs. This bound is significantly larger than when jobs are constant sized. A variant of exponential backoff, however, achieves makespan O(V logV) with high probability. Finally, we introduce a new protocol, size-hashed backoff, specifically designed for jobs of multiple sizes that achieves makespan O(V log 3 logV). The error probability of the first two bounds is polynomially small in n and the latter is polynomially small in logV.

Mineral status, metabolism and performance of dairy heifers receiving a combined trace element bolus and out-wintered on perennial ryegrass, kale or fodder beet

The effects of a cobalt (Co), copper (Cu), selenium (Se), and iodine (I) trace-mineral ruminal bolus on the mineral status and performance of out-wintered, pregnant dairy heifers was investigated. Nine commercial farms grazing pasture (G), kale (K), or fodder beet (F) were used (n=3 per forage), with forty heifers on each farm randomly allocated to not receive (B-) or receive (B+) two combined mineral boluses. Mean plasma Co concentrations were 0.021 and 0.041 µmol/L in B- and B+ respectively (p 0.05), however condition score was higher (p < 0.05) in B+ at the end of the study. It is concluded that the provision of a trace mineral bolus increased plasma concentrations of the minerals supplied, with the greatest benefits in animals grazing kale, but these increases were not translated into improved performance

Detailed study of the ac susceptibility of Sr2RuO4 in oriented magnetic fields

We have investigated the ac susceptibility of the spin triplet superconductor Sr$_2$RuO$_4$ as a function of magnetic field in various directions at temperatures down to 60 mK. We have focused on the in-plane field configuration (polar angle $\theta \simeq 90^{\circ}$), which is a prerequisite for inducing multiple superconducting phases in Sr$_2$RuO$_4$. We have found that the previous attribution of a pronounced feature in the ac susceptibility to the second superconducting transition itself is not in accord with recent measurements of the thermal conductivity or of the specific heat. We propose that the pronounced feature is a consequence of additional involvement of vortex pinning originating from the second superconducting transition.Comment: Accepted for publication in Phys. Rev.

The symmetry of the superconducting order parameter in PuCoGa5_5

The symmetry of the superconducting order parameter in single-crystalline PuCoGa$_5$ ($T_{\rm c} = 18.5$ K) is investigated via zero- and transverse- field muon spin relaxation ($\mu$SR) measurements, probing the possible existence of orbital and/or spin moments (time reversal-symmetry violation TRV) associated with the superconducting phase and the in-plane magnetic-field penetration depth $\lambda(T)$ in the mixed state, respectively. We find no evidence for TRV, and show that the superfluid density, or alternatively, $\Delta\lambda(T) = \lambda(T) - \lambda(0)$, are $\propto T$ for $T/T_{\rm c} \leq 0.5$. Taken together these measurements are consistent with an even-parity (pseudo-spin singlet), d-wave pairing state.Comment: 4 pages, 5 figure

Observation of a Transition from BCS to HTSC-like Superconductivity in Ba_{1-x}K_xBiO_3 Single Crystals

A study of temperature dependences of the upper critical field B_{c2}(T) and surface impedance Z(T)=R(T)+iX(T) in Ba_{1-x}K_xBiO_3 single crystals that have transition temperatures in the range 6 x>0.4) reveals a transition from BCS to unusual type of superconductivity. B_{c2}(T) curves corresponding to the crystals that have T_c>20 K have positive curvature (like in some HTSC), and those of the crystals with T_c<15 K fall on the usual Werthamer-Helfand-Hohenberg curve. R(T) and X(T) dependences of the crystals with T_c~30 K and T_c~11 K are respectively linear (like in HTSC) and exponential (BCS) in the temperature range T << T_c. The experimental results are discussed in connection with the extended saddle point model by Abrikosov.Comment: 5 pages, 5 figure

Added dietary sulfur and molybdenum has a greater influence on hepatic copper concentration, intake, and performance in Holstein-Friesian dairy cows offered a grass silage- rather than corn silage-based diet

To test the hypothesis that the metabolism of Cu in dairy cows is affected by basal forage and added S and Mo, 56 dairy cows that were 35 (standard error ± 2.2) days postcalving and yielding 38.9 kg of milk/d (standard error ± 0.91) were offered 1 of 4 diets in a 2 × 2 factorial design for a 14-wk period. The 4 diets contained approximately 20 mg of Cu/kg of dry matter (DM), and had a corn silage-to-grass silage ratio of 0.75:0.25 (C) or 0.25:0.75 (G) and were either unsupplemented (−) or supplemented (+) with an additional 2 g of S/kg of DM and 6.5 mg of Mo/kg of DM. We found an interaction between forage source and added S and Mo on DM intake, with cows offered G+ having a 2.1 kg of DM lower intake than those offered G−, but no effect on the corn silage-based diets. Mean milk yield was 38.9 kg/d and we observed an interaction between basal forage and added S and Mo, with yield being decreased in cows offered G+ but increased on C+. No effect of dietary treatment on milk composition or live weight was noted, but body condition was lower in cows fed added S and Mo irrespective of forage source. We found an interaction between forage source and added S and Mo on milk somatic cell count, which was higher in cows offered G+ compared with G−, but not in cows fed the corn silage-based diets, although all values were low (mean values of 1.72, 1.50, 1.39, and 1.67 log10/mL for C−, C+, G−, and G+, respectively). Mean plasma Cu, Fe, and Mn concentrations were 13.8, 41.3, and 0.25 µmol/L, respectively, and were not affected by dietary treatment, whereas plasma Mo was 0.2 µmol/L higher in cows receiving added S and Mo. The addition of dietary S and Mo decreased liver Cu balance over the study period in cows fed either basal forage, but the decrease was considerably greater in cows receiving the grass silage-based diet. Similarly, hepatic Fe decreased more in cows receiving G than C when S and Mo were included in the diet. We concluded that added S and Mo reduces hepatic Cu reserves irrespective of basal forage source, but this decrease is considerably more pronounced in cows receiving grass silage- than corn silage-based rations and is associated with a decrease in intake and milk performance and an increase in milk somatic cell count

The Alaska Arctic Vegetation Archive (AVA-AK)

The Alaska Arctic Vegetation Archive (AVA-AK, GIVD-ID: NA-US-014) is a free, publically available database archive of vegetation-plot data from the Arctic tundra region of northern Alaska. The archive currently contains 24 datasets with 3,026 non-overlapping plots. Of these, 74% have geolocation data with 25-m or better precision. Species cover data and header data are stored in a Turboveg database. A standardized Pan Arctic Species List provides a consistent nomenclature for vascular plants, bryophytes, and lichens in the archive. A web-based online Alaska Arctic Geoecological Atlas (AGA-AK) allows viewing and downloading the species data in a variety of formats, and provides access to a wide variety of ancillary data. We conducted a preliminary cluster analysis of the first 16 datasets (1,613 plots) to examine how the spectrum of derived clusters is related to the suite of datasets, habitat types, and environmental gradients. We present the contents of the archive, assess its strengths and weaknesses, and provide three supplementary files that include the data dictionary, a list of habitat types, an overview of the datasets, and details of the cluster analysis

TEM-EELS study of low-friction superlattice TiAlN/VN coating: the wear mechanisms

A 20-50 nm thick tribofilm was generated on the worn surface of a multilayer coating TiAlN/VN after dry sliding test against an alumina counterpart. The tribofilm was characterized by applying analytical transmission electron microscopy techniques with emphasis on detailed electron energy loss spectrometry and energy loss near edge structure analysis. Pronounced oxygen in the tribofilm indicated a predominant tribo-oxidation wear. Structural changes in the inner-shell ionization edges of N, Ti and V suggested decomposition of nitride fragments

Egg production of Baltic cod (Gadus morhua) in relation to variable sex ratio, maturity, and fecundity

Observed fluctuations in relative fecundity of Eastern Baltic cod (Gadus morhua L.) were related to food availability during the main feeding period and were used to develop a predictive model that explained 72% of the interannual variations in fecundity. Time series of sex ratios, maturity ogives, and relative fecundity were combined with mean weights-at-age and stock sizes from an analytical multispecies model to estimate the potential egg production (PEP). Relationships between PEP and independent estimates of realized daily and seasonal egg production from egg surveys were highly significant. The difference between estimates of potential and realized seasonal egg production was of a magnitude corresponding to the expected loss of eggs as a result of atresia, fertilization failure, and early egg mortality. The removal of interannual variability in sex ratio, maturity, and fecundity on estimates of PEP deteriorated the relationships in all three cases. PEP proved to be superior to spawning stock biomass as measure of the reproductive potential in a stock-recruitment relationship of Eastern Baltic cod. PEP in combination with the reproductive volume explained 61% of the variation in year-class strength at age 2