1,536 research outputs found
Structure of a sheared soft-disk fluid from a nonequilibrium potential
The distortion of structure of a simple, inverse-12, soft-disk fluid undergoing two-dimensional plane Couette flow was studied by nonequilibrium molecular dynamics (NEMD) simulation and by equilibrium Monte Carlo (MC) simulation with a nonequilibrium potential, under which the equilibrium structure of the fluid is that of the nonequilibrium fluid. Extension of the iterative predictor-corrector method of [Reatto Phys. Rev. A 33 3451 (1986)] was used to extract the nonequilibrium potential with the structure input from the NEMD simulation. Very good agreement for the structural properties and pressure tensor generated by the NEMD and MC simulation methods was found, thus providing the evidence that nonequilibrium liquid structure can be accurately reproduced via simple equilibrium simulations or theories using a properly chosen nonequilibrium potential. The method developed in the present study and numerical results presented here can be used to guide and test theoretical developments, providing them with the "experimental" results for the nonequilibrium potential.open2
Continuous-culture fermentation as a tool for forage evaluation
Ruminal degradation of organic matter and protein in alfalfa and prairie hay were evaluated in vivo, using cannulated cows, and in vitro, using a continuous-culture fermenter to simulate ruminal fermentation. Estimates of organic matter degradability, microbial N flow per unit feed N input, and efficiency of microbial growth were not different (P\u3e.10) between the in vivo and in vitro systems. However, for both forages, estimates of nitrogen degradability were greater with the in vitro system. Despite the differences between in vivo and in vitro techniques for some variables, continuous-culture fermentation will allow us to compare the effects of dietary treatments on forage digestion and will aid in the formulation of supplements to meet specific nutrient requirements for cattle consuming forage-based diets
Influence of increasing proportion of supplemental nitrogen from urea on intake and fermentation characteristics in beef steers consuming low-quality, tallgrass-prairie forage
Five ruminally and duodenally fistulated
Angus × Hereford steers were used to determine
intake and fermentation responses associated
with increasing the proportion of supplemental
degradable intake protein (DIP) provided
by urea. Steers had free access to a dormant,
tallgrass-prairie forage. The supplemental
DIP was provided by sodium caseinate
and (or) urea , at a level that was determined
previously to optimize use of a similar forage.
Supplemental DIP was balanced with corn
starch to provide a final supplement of 40%
crude protein. Percentages of DIP from urea
were: 0, 25, 50, 75, and 100%. Supplements
were given intraruminally. Increasing the percentage
of urea as supplemental DIP from urea
did not significantly affect forage DM intake;
however, fermentation characteristics changed
Exile
Byron rehearsed going into exile in 1809, when he was twenty-one years old. Before setting sail for Lisbon, he wrote, “I leave England without regret, I shall return to it without pleasure. – I am like Adam the first convict sentenced to transportation, but I have no Eve, and have eaten no apple but what was sour as a crab and thus ends my first Chapter” (BLJ 1: 211). Byron’s sardonic perception of himself as a biblical exile foreshadowed the allusive character of his second longer-term exile at the age of twenty-eight, when his carefully staged exit required an audience (some of the same friends and servants), expensive props (a replica of Napoleon’s carriage) and a literary precursor. On his last evening in England, Byron visited the burial place of the satirist Charles Churchill, and lay down on his grave. It was a performance of immense weariness with life and solidarity with an embittered outcast.Postprin
The Lake Poets
“If Southey had not been comparatively good,” writes Herbert F. Tucker, “he would never have drawn out Byron’s best in those satirical volleys that were undertaken, at bottom, in order to reprehend not the want of talent but its wastage.” And if Wordsworth and Coleridge had not been dangerously talented, Byron might have spared them some of his stinging sallies. In Table Talk Coleridge proclaimed the conclusion of the “intellectual war” Byron threatened in Don Juan (XI. 62: 496), declaring Wordsworth the poet who “will wear the crown,” triumphing over Byron and his ilk for the poetic laurels of the Romantic period. But Byron was not simply an opponent of his contemporaries. His responses to the Lake poets, particularly to Wordsworth, ran the gamut from “reverence” (HVSV, 129) then “nausea” (Medwin, 237) to Don Juan’s comical though cutting disdain, in under a decade. Focusing on Byron’s relationship with Wordsworth and Coleridge, I will show how Byron’s poetry and drama reveal the range and complexity of his dialogue with his older peers, where, even at their most apparently divergent, the conversation between the poets reveals the depth of the engagement across their works
Two Earth-sized planets orbiting Kepler-20
Since the discovery of the first extrasolar giant planets around Sun-like
stars, evolving observational capabilities have brought us closer to the
detection of true Earth analogues. The size of an exoplanet can be determined
when it periodically passes in front of (transits) its parent star, causing a
decrease in starlight proportional to its radius. The smallest exoplanet
hitherto discovered has a radius 1.42 times that of the Earth's radius (R
Earth), and hence has 2.9 times its volume. Here we report the discovery of two
planets, one Earth-sized (1.03R Earth) and the other smaller than the Earth
(0.87R Earth), orbiting the star Kepler-20, which is already known to host
three other, larger, transiting planets. The gravitational pull of the new
planets on the parent star is too small to measure with current
instrumentation. We apply a statistical method to show that the likelihood of
the planetary interpretation of the transit signals is more than three orders
of magnitude larger than that of the alternative hypothesis that the signals
result from an eclipsing binary star. Theoretical considerations imply that
these planets are rocky, with a composition of iron and silicate. The outer
planet could have developed a thick water vapour atmosphere.Comment: Letter to Nature; Received 8 November; accepted 13 December 2011;
Published online 20 December 201
Evaluation of Two Methods to Estimate and Monitor Bird Populations
Background: Effective management depends upon accurately estimating trends in abundance of bird populations over time, and in some cases estimating abundance. Two population estimation methods, double observer (DO) and double sampling (DS), have been advocated for avian population studies and the relative merits and short-comings of these methods remain an area of debate. Methodology/Principal Findings: We used simulations to evaluate the performances of these two population estimation methods under a range of realistic scenarios. For three hypothetical populations with different levels of clustering, we generated DO and DS population size estimates for a range of detection probabilities and survey proportions. Population estimates for both methods were centered on the true population size for all levels of population clustering and survey proportions when detection probabilities were greater than 20%. The DO method underestimated the population at detection probabilities less than 30 % whereas the DS method remained essentially unbiased. The coverage probability of 95 % confidence intervals for population estimates was slightly less than the nominal level for the DS method but was substantially below the nominal level for the DO method at high detection probabilities. Differences in observer detection probabilities did not affect the accuracy and precision of population estimates of the DO method. Population estimates for the DS method remained unbiased as the proportion of units intensively surveyed changed, but the variance of th
Depression and Sexual Orientation During Young Adulthood: Diversity Among Sexual Minority Subgroups and the Role of Gender Nonconformity.
Sexual minority individuals are at an elevated risk for depression compared to their heterosexual counterparts, yet less is known about how depression status varies across sexual minority subgroups (i.e., mostly heterosexuals, bisexuals, and lesbians and gay men). Moreover, studies on the role of young adult gender nonconformity in the relation between sexual orientation and depression are scarce and have yielded mixed findings. The current study examined the disparities between sexual minorities and heterosexuals during young adulthood in concurrent depression near the beginning of young adulthood and prospective depression 6 years later, paying attention to the diversity within sexual minority subgroups and the role of gender nonconformity. Drawn from the National Longitudinal Study of Adolescent Health (N = 9421), we found that after accounting for demographics, sampling weight, and sampling design, self-identified mostly heterosexual and bisexual young adults, but not lesbians and gay men, reported significantly higher concurrent depression compared to heterosexuals; moreover, only mostly heterosexual young adults were more depressed than heterosexuals 6 years later. Furthermore, while young adult gender nonconforming behavior was associated with more concurrent depression regardless of sexual orientation, its negative impact on mental health decreased over time. Surprisingly, previous gender nonconformity predicted decreased prospective depression among lesbians and gay men whereas, among heterosexual individuals, increased gender nonconformity was not associated with prospective depression. Together, the results suggested the importance of investigating diversity and the influence of young adult gender nonconformity in future research on the mental health of sexual minorities.The authors acknowledge support for this research: the University of Arizona Norton School of Family and Consumer Sciences Fitch Nesbitt Endowment and a University of Arizona Graduate Access Fellowship to the second author. This research uses data from Add Health, a program project directed by Kathleen Mullan Harris and designed by J. Richard Udry, Peter S. Bearman, and Kathleen Mullan Harris at the University of North Carolina at Chapel Hill, and funded by grant P01-HD31921 from the Eunice Kennedy Shriver National Institute of Child Health and Human Development, with cooperative funding from 23 other federal agencies and foundations. Special acknowledgment is due Ronald R. Rindfuss and Barbara Entwisle for assistance in the original design. Information on how to obtain the Add Health data files is available on the Add Health website (http://www.cpc.unc.edu/addhealth). No direct support was received from grant P01-HD31921 for this analysis. The authors thank Noel Card and Susan Stryker for comments on the previous versions of this article and Richard Lippa and Katerina Sinclair for methodological and statistical consult. The authors also thank the anonymous reviewers and the Editor for their helpful comments.This is the accepted manuscript of a paper published in Archives of Sexual Behavior (Li G, Pollitt AM, Russell ST, Archives of Sexual Behavior 2015, doi:10.1007/s10508-015-0515-3). The final version is available at http://dx.doi.org/10.1007/s10508-015-0515-3
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