Quantum criticalities in a two-leg antiferromagnetic S=1/2 ladder induced by a staggered magnetic field

We study a two-leg antiferromagnetic spin-1/2 ladder in the presence of a staggered magnetic field. We consider two parameter regimes: strong (weak) coupling along the legs and weak (strong) coupling along the rungs. In both cases, the staggered field drives the Haldane spin-liquid phase of the ladder towards a Gaussian quantum criticality. In a generalized spin ladder with a non-Haldane, spontaneously dimerized phase, the staggered magnetic field induces an Ising quantum critical regime. In the vicinity of the critical lines, we derive low-energy effective field theories and use these descriptions to determine the dynamical response functions, the staggered spin susceptibility and the string order parameter.Comment: 29 pages of revtex, 10 figure

Correlation gap in the heavy-fermion antiferromagnet UPd_2Al_3

The optical properties of the heavy-fermion compound UPd$_2$Al$_3$ have been measured in the frequency range from 0.04 meV to 5 meV (0.3 to 40 cm$^{-1}$) at temperatures $2 {\rm K}<T< 300$ K. Below the coherence temperature $T^*\approx 50$ K, the hybridization gap opens around 10 meV. As the temperature decreases further ($T\leq 20$ K), a well pronounced pseudogap of approximately 0.2 meV develops in the optical response; we relate this to the antiferromagnetic ordering which occurs below $T_N\approx 14$ K. The frequency dependent mass and scattering rate give evidence that the enhancement of the effective mass mainly occurs below the energy which is associated to the magnetic correlations between the itinerant and localized 5f electrons. In addition to this correlation gap, we observe a narrow zero-frequency conductivity peak which at 2 K is less than 0.1 meV wide, and which contains only a fraction of the delocalized carriers. The analysis of the spectral weight infers a loss of kinetic energy associated with the superconducting transition.Comment: RevTex, 15 pages, 7 figure

Fish meal as a protein source for holstein steer calves

Holstein steer calves (n = 96) were on experiment from 8 to 18 wk of age. Control calves were fed a diet in which all supplemental protein was from soybean meal; in the experimental diet, part of the soybean meal was replaced by fish meal. Both feeds were readily consumed, and consumption did not differ between treatments. Gains of calves fed fish meal were greater (P = .10) during the first 8 wk of the experiment; however, over the entire experiment, the difference was not significant. Overall results suggest that fish meal may improve weight gains and feed efficiency of younger and smaller calves

Evaluation of milk replacers containing new protein soruces and a probiotic

The objectives of this experiment were to evaluate bovine and porcine plasma proteins as sources of protein for calf milk replacers and to evaluate a commercial probiotic. Four replacers were compared; an all milk protein control, two replacers with 25% of protein from bovine plasma protein or porcine plasma protein, and a replacer identical to the control except that it contained a probiotic (Biomate FG, Chr. Hansen's Laboratory) instead of antibiotic. The 120 bull calves (7 ± 3 days of age) were divided into four equal groups, and calves from each group were fed 4 quarts per day of one of the replacers until weaned and all of a commercial starter they would eat. For the control, porcine plasma, bovine plasma, and probiotic replacer groups, respectively, during the 6-wk period, the weight gains were 23.8, 29.5, 27.9, and 22.2 lb. Starter consumptions were 53.7, 67.8, 58.7, and 54.6 lb, respectively. Deaths were 2, 1, 3, and 0, respectively. Increases in wither height were similar among diets. Increases in weight gains and starter consumed by calves fed the plasma proteins compared to controls approached significance (P = .10); differences between control and probiotic replacer groups were not significant

Effect of 1174® Silage Inoculant on the fermentation of corn silages

The effect of 1174® Silage Inoculant on the ensiling process was studied using three Pioneer corn hybrids. All hybrids fermented rapidly, and 1174 did not significantly influence any of the fermentation characteristics during the 120 days. The epiphytic lactic acid bacteria (LAB) counts on the chopped corn plants were high; 14 times greater than the numbers of LAB provided by the inoculant. Although during fermentation, statistically significant differences occurred among the hybrids for fermentation end-products, no observed trends suggested that hybrid effects were real

Effects of Biomate® inoculant and dextrose on the fermentation of alfalfa silages

This study documented once again that ensiling alfalfa is difficult and unpredictable. Adding 2% dextrose or Biomate® inoculant alone or in combination had little influence on the ensiling process but did improve fermentation efficiency somewhat. The pre-ensiling characteristics (i.e., dry matter (DM) and water soluble carbohydrate (WSC) values, buffering capacity, and epiphytic microflora) at the different cuttings and stages of maturity undoubtedly influenced the effectiveness of the two additives. Apparently, alfalfa often has too little WSC and too much buffering capacity to produce adequately preserved silage, especially when ensiled at a low DM content (less than 30 to 34%)

Comparison of growth and production of holstein heifers raised on 100% or 115% of the NRC requirements

The 1990 Annual KSU Dairy Day is known as Dairy Day, 1990One hundred and ten Holstein heifers from the KSU Dairy Research Unit were used in this experiment. They were fed either 100% (control) or 115% (enhanced) of NRC requirements for energy, protein, major minerals, and vitamins from 6 mo of age to shortly before calving. Heifers in the enhanced group calved at an earlier age, had larger heart girths, and were heavier than controls. At this time, 46 of the heifers have completed at least 50 days in lactation. Based on their projected 305-2X-ME records, the heifers in the enhanced group have produced slightly, but not significantly, more milk and milk fat