Driven activation versus thermal activation

Activated dynamics in a glassy system undergoing steady shear deformation is studied by numerical simulations. Our results show that the external driving force has a strong influence on the barrier crossing rate, even though the reaction coordinate is only weakly coupled to the nonequilibrium system. This "driven activation" can be quantified by introducing in the Arrhenius expression an effective temperature, which is close to the one determined from the fluctuation-dissipation relation. This conclusion is supported by analytical results for a simplified model system.Comment: 5 pages, 3 figure

The effects of video game play on the characteristics of saccadic eye movements

AbstractVideo game play has become a common leisure activity all around the world. To reveal possible effects of playing video games, we measured saccades elicited by video game players (VGPs) and non-players (NVGPs) in two oculomotor tasks. First, our subjects performed a double-step task. Second, we asked our subjects to move their gaze opposite to the appearance of a visual target, i.e. to perform anti-saccades. As expected on the basis of previous studies, VGPs had significantly shorter saccadic reaction times (SRTs) than NVGPs for all saccade types. However, the error rates in the anti-saccade task did not reveal any significant differences. In fact, the error rates of VGPs were actually slightly lower compared to NVGPs (34% versus 40%, respectively). In addition, VGPs showed significantly higher saccadic peak velocities in every saccade type compared to NVGP. Our results suggest that faster SRTs in VGPs were associated with a more efficient motor drive for saccades. Taken together, our results are in excellent agreement with earlier reports of beneficial video game effects through the general reduction in SRTs. Our data clearly provides additional experimental evidence for an higher efficiency of the VGPs on the one hand and refutes the notion of a reduced impulse control in VGPs on the other

Restoration vs. New Construction: How to Make the Right Decision

Restoration or new construction? That is a dilemma that educational leaders, particularly superintendents and school business officials, have had to wrestle with for years. In the past, state regulations often dictated whether school buildings should be renovated or torn down to make way for new construction. State reimbursement guidelines favored new construction over restoration for public school development by either withholding funds or denying the full state support for restoration projects. In fact, some states established complex formulas that mandated new construction if the cost of restoration exceeded approximately two-thirds of the new construction costs. Reversing the mindset among many educators and legislators that new construction is always the best option for districts has not been an easy sell for designers, preservationists, and school architects. However, restoration of school properties has been on the rise in recent years, fueled by citizens’ interest in maintaining community landmarks, by districts’ recognition of the importance of preserving existing schools as important community institutions, and by demonstrating that the restoration of aging buildings can be a cost-effective way to preserve history and create safe and exciting educational facilities

School Vouchers: Blessing or Curse for Catholic High Schools?

The voucher debate has thus far focused almost exclusively on elementary schools. Since Catholic and private high schools tend to be more expensive to operate than elementary schools, this article hypothesizes about the potential future impact of voucher programs on Catholic high schools

NaOH wheat silage and alfalfa haylage for growing steers and heifers

Wheat silage, with and without sodium hydroxide (NaOH), was fed, with or without alfalfa haylage, in an 80-day growing trial. Calves fed NaOH-silage consumed 18% more feed and gained 16% faster than those fed control silage, but feed efficiencies were similar. When 50% of the wheat silage was replaced with alfalfa haylage (DM basis), gains decreased 3.1 and 3.7%, feed intake increased 12.3 and 9.7%, and feed efficiency decreased 23.7 and 14.4% for calves fed control and NaOH silages, respectively. NaOH increased ensiling temperatures by 9 to 12° C during the first 6 weeks. Dry matter recovery from the concrete stave silos was similar for both silages (82.1% for control and 83.9% for NaOH); recoveries from buried bags were 92.3 and 89.5%. NaOH wheat silage was more stable in air than was either control wheat silage or alfalfa haylage

Whole-plant forage and grain sorghum silages for growing cattle

Four trials were conducted to determine the feeding value of whole-plant forage and grain sorghum silages. In general, growing cattle fed grain sorghum hybrids (NK2778, Funk\u27s 550, DeKalb 42Y, DeKalb E67) out performed those fed forage sorghum silages. Only moderate to high grain-content, forage sorghums (Buffalo Canex, Pioneer 947, Acco 351) gave performances that approached the grain sorghums. Low grain-content and nonheading forage sorghums (DeKalb 25E, Funk\u27s G-1990) resulted in the poorest cattle performance. These studies indicate that grain content of a sorghum silage is the major determinant of cattle performance and that whole-plant grain sorghums should produce the fastest and most efficient gains in growing programs

Drought-stressed, irrigated, and additive-treated corn silages for growing cattle

Cattle fed drought-stressed corn silage gained about 10% slower but were just as efficient as cattle fed irrigated corn silage. Because the irrigated corn out yielded the drought corn (17.4 VS. 8.2 tons per acre), the irrigated silage gave a much higher cattle gain per acre (1928 VS. 940 1b). Silo Guard II®-treated silage had an advantage in DM recovery and feed conversion over its control and produced 4.6 more pounds of cattle gain per ton of crop ensiled. Cattle fed H/M Inoculant®- treated silage gained significantly faster than cattle fed the control, however, the treated silage gave only slight improvements in DM recovery and gain per ton of crop ensiled

Shear-induced anisotropic decay of correlations in hard-sphere colloidal glasses

Spatial correlations of microscopic fluctuations are investigated via real-space experiments and computer simulations of colloidal glasses under steady shear. It is shown that while the distribution of one-particle fluctuations is always isotropic regardless of the relative importance of shear as compared to thermal fluctuations, their spatial correlations show a marked sensitivity to the competition between shear-induced and thermally activated relaxation. Correlations are isotropic in the thermally dominated regime, but develop strong anisotropy as shear dominates the dynamics of microscopic fluctuations. We discuss the relevance of this observation for a better understanding of flow heterogeneity in sheared amorphous solids.Comment: 6 pages, 4 figure

Fluctuation relations and coarse-graining

We consider the application of fluctuation relations to the dynamics of coarse-grained systems, as might arise in a hypothetical experiment in which a system is monitored with a low-resolution measuring apparatus. We analyze a stochastic, Markovian jump process with a specific structure that lends itself naturally to coarse-graining. A perturbative analysis yields a reduced stochastic jump process that approximates the coarse-grained dynamics of the original system. This leads to a non-trivial fluctuation relation that is approximately satisfied by the coarse-grained dynamics. We illustrate our results by computing the large deviations of a particular stochastic jump process. Our results highlight the possibility that observed deviations from fluctuation relations might be due to the presence of unobserved degrees of freedom.Comment: 19 pages, 6 figures, very minor change