1,841 research outputs found

    An expression for stationary distribution in nonequilibrium steady state

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    We study the nonequilibrium steady state realized in a general stochastic system attached to multiple heat baths and/or driven by an external force. Starting from the detailed fluctuation theorem we derive concise and suggestive expressions for the corresponding stationary distribution which are correct up to the second order in thermodynamic forces. The probability of a microstate η\eta is proportional to exp[Φ(η)]\exp[{\Phi}(\eta)] where Φ(η)=kβkEk(η){\Phi}(\eta)=-\sum_k\beta_k\mathcal{E}_k(\eta) is the excess entropy change. Here Ek(η)\mathcal{E}_k(\eta) is the difference between two kinds of conditioned path ensemble averages of excess heat transfer from the kk-th heat bath whose inverse temperature is βk\beta_k. Our expression may be verified experimentally in nonequilibrium states realized, for example, in mesoscopic systems.Comment: 4 pages, 2 figure

    Persistence of orally administered Megasphaera elsdenii and Ruminococcus bromii in the rumen of beef cattle fed a high grain (barley) diet

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    When cattle are fed grain, acidotic ruminal conditions and decreased efficiency in starch utilisation can result from the rapid production and accumulation of lactic acid in the rumen. The efficacy of drenching cattle with Megasphaera elsdenii and Ruminococcus bromii to improve animal performance was investigated. A feedlot trial was undertaken with 80 Bos indicus crossbred steers (initial liveweight 347.1 (s.d. 31.7) kg) in 10 pens in a randomised complete block design. An empty-pen-buffer was maintained between treated (inoculated) and untreated (control) groups to avoid transfer of inoculant bacteria to the control steers. Inoculated steers were orally drenched with M. elsdenii YE34 and R. bromii YE282, and populations increased rapidly over 3-14 days. The steers were fed for a total of 70 days with commercial, barley-based, feedlot rations. High growth rates (1.91 kg per day) were achieved throughout the experiment in both the inoculated and control steers. Intakes averaged 21.3 g dry matter (DM) per kg liveweight per day. There was probably no acidosis achieved in this trial following challenge (i.e. no change in pH occurred). There were no differences in any production or carcass measurements between the control and inoculated steers overall. However, the control group acquired dense ruminal populations of M. elsdenii by Day 14, while R. bromii populations established at high densities within the first 2 weeks but then declined and were undetectable by Day 50. R. bromii appears to be only transiently dominant, and once its dominance waned, it appeared that Ruminobacter spp. established in the rumen. Ruminobacter spp. became dominant between 14 and 28 days in all the steers examined and persisted through to the end of the study. These Ruminobacter spp. may be of future interest in the development of probiotics for grain-fed cattle

    Assessing the Use of Molecular Barcoding and qPCR for Investigating the Ecology of Prorocentrum minimum (Dinophyceae), a Harmful Algal Species

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    Prorocentrum minimum is a species of marine dinoflagellate that occurs worldwide and can be responsible for harmful algal blooms (HABs). Some studies have reported it to produce tetrodotoxin; however, results have been inconsistent. qPCR and molecular barcoding (amplicon sequencing) using high-throughput sequencing have been increasingly applied to quantify HAB species for ecological analyses and monitoring. Here, we isolated a strain of P. minimum from eastern Australian waters, where it commonly occurs, and developed and validated a qPCR assay for this species based on a region of ITS rRNA in relation to abundance estimates from the cultured strain as determined using light microscopy. We used this tool to quantify and examine ecological drivers of P. minimum in Botany Bay, an estuary in southeast Australia, for over ~14 months in 2016-2017. We compared abundance estimates using qPCR with those obtained using molecular barcoding based on an 18S rRNA amplicon. There was a significant correlation between the abundance estimates from amplicon sequencing and qPCR, but the estimates from light microscopy were not significantly correlated, likely due to the counting method applied. Using amplicon sequencing, ~600 unique actual sequence variants (ASVs) were found, much larger than the known phytoplankton diversity from this region. P. minimum abundance in Botany Bay was found to be significantly associated with lower salinities and higher dissolved CO2 levels

    Strategies to increase growth of weaned Bali calves

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    Demand for beef in Indonesia is increasing by 4% per annum, which is unable to be met from domestic supply alone under prevailing cattle management systems. Small-holder farmers within the crop-livestock system of eastern Indonesia have the opportunity to capitalise on this increased demand for beef. An Integrated Village Management System (IVMS) established in Nusa Tenggara Barat successfully increased reproductive output by introducing natural mating, early weaning and more appropriate allocation of available feed resources to match nutrient demands of cattle. It is anticipated that wide scale implementation of the IVMS will result in a large population of early weaned calves across eastern Indonesia and that if these calves are retained by small-holder farmers, and growth rates improved, significant increases in cash flow will ensue. The objective of this project was to evaluate a range of feeding strategies to increase growth rates of 6 month old weaned Bali calves at four sites across eastern Indonesia

    Oral health and pathology: a macrophage account.

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    Macrophages are present in healthy oral mucosa and their numbers increase dramatically during disease. They can exhibit a diverse range of phenotypes characterised as a functional spectrum from pro-inflammatory to anti-inflammatory (regulatory) subsets. This review illustrates the role of these subsets in the oral inflammatory disease lichen planus, and the immunosuppressive disease oral squamous cell carcinoma (SCC). We conclude that the role of macrophages in driving progression in oral disease identifies them as potential therapeutic targets for a range of oral pathologies

    Quantification Of The Efficiency Of Rumen Microbial Protein Synthesis In Steers Fed Green Tropical Grass

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    The rate of rumen microbial crude protein (MCP) supply to the intestines is a crucial element in the current rumen models to predict respond of ruminants to a certain diet. Data from tropical pastures always below predicted results from the existing rumen models. Thus, quantification of the rumen MCP supply from tropical grass will improve predictive rate under tropical feeding conditions. Four Brahman crossbred steers (457±20.1 kg) were used in a metabolism study. Pangola grass (Digitaria erianthe cv. Steudal) was harvested every morning and fed to the animals soon after. Parameters measured were EMPS, intake, fractional passage rates, and rumen ammonia concentration. The EMPS was estimated using purine derivative excretion in urine. Crude protein and water soluble carbohydrates content were 6.3 and 7.4% of dry matter (DM) respectively. DM intake was 1.6% live weight. Average rumen ammonia concentration was 69 mg/L whilst rumen passage rates were 7.84 and 6.92 %/h for fluid and solids respectively. EMPS was only 72 g MCP/kg digestible organic matter. It might be concluded that EMPS in steers consuming green pangola grass was below the minimum level for forage diets adopted in the current feeding standards

    Phase-space approach to dynamical density functional theory

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    We consider a system of interacting particles subjected to Langevin inertial dynamics and derive the governing time-dependent equation for the one-body density. We show that, after suitable truncations of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy, and a multiple time scale analysis, we obtain a self-consistent equation involving only the one-body density. This study extends to arbitrary dimensions previous work on a one-dimensional fluid and highlights the subtelties of kinetic theory in the derivation of dynamical density functional theory

    Extended Clausius Relation and Entropy for Nonequilibrium Steady States in Heat Conducting Quantum Systems

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    Recently, in their attempt to construct steady state thermodynamics (SST), Komatsu, Nakagwa, Sasa, and Tasaki found an extension of the Clausius relation to nonequilibrium steady states in classical stochastic processes. Here we derive a quantum mechanical version of the extended Clausius relation. We consider a small system of interest attached to large systems which play the role of heat baths. By only using the genuine quantum dynamics, we realize a heat conducting nonequilibrium steady state in the small system. We study the response of the steady state when the parameters of the system are changed abruptly, and show that the extended Clausius relation, in which "heat" is replaced by the "excess heat", is valid when the temperature difference is small. Moreover we show that the entropy that appears in the relation is similar to von Neumann entropy but has an extra symmetrization with respect to time-reversal. We believe that the present work opens a new possibility in the study of nonequilibrium phenomena in quantum systems, and also confirms the robustness of the approach by Komtatsu et al.Comment: 19 pages, 2 figure

    The Boltzmann Entropy for Dense Fluids Not in Local Equilibrium

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    We investigate, via computer simulations, the time evolution of the (Boltzmann) entropy of a dense fluid not in local equilibrium. The macrovariables MM describing the system are the (empirical) particle density f=\{f(\un{x},\un{v})\} and the total energy EE. We find that S(ft,E)S(f_t,E) is monotone increasing in time even when its kinetic part is decreasing. We argue that for isolated Hamiltonian systems monotonicity of S(Mt)=S(MXt)S(M_t) = S(M_{X_t}) should hold generally for ``typical'' (the overwhelming majority of) initial microstates (phase-points) X0X_0 belonging to the initial macrostate M0M_0, satisfying MX0=M0M_{X_0} = M_0. This is a direct consequence of Liouville's theorem when MtM_t evolves autonomously.Comment: 8 pages, 5 figures. Submitted to PR

    Responses to various protein and energy supplements by steers fed low-quality tropical hay. 2. Effect of stage of maturity of steers

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    Dose response curves to various supplements were established in two pen-feeding experiments (Exp1 and Exp2) with Bos indicus crossbred steers of two age groups (Young, 10–12 months; Old, 33–36 months) fed low-quality tropical grass hays ad libitum. Diets included supplements based on (Exp1) cottonseed meal (CSM; intake (as fed) 0–10 g/kg liveweight (W).day) and a barley mix (Bar; 0–20 g/kg W.day) and (Exp2) a molasses mix (MUP) and a Bar mix, both fed at 0–20 g/kg W.day. Urea was provided with the Bar mixes and urea/copra meal with the MUP mix. Growth rates of Young steers increased linearly with Bar and MUP supplements but asymptotically with CSM whereas those of Old steers increased asymptotically with all supplement types. With supplement intake expressed on a liveweight basis (g/kg W.day), responses were greater for both steer age groups with CSM compared with Bar (Young, P < 0.001; Old, P < 0.01) and Bar compared with MUP treatments (Young, P < 0.01; Old, P < 0.05). Furthermore, Old steers outperformed their Young counterparts with both CSM (P < 0.05) and Bar (P < 0.001) supplements fed in Exp1 and with Bar and MUP supplements (P < 0.01) fed in Exp2. When supplement intake was expressed in absolute terms (kg/day), growth responses were not different between age groups for different supplements except that Old steers had a higher daily W gain on Bar than their Young counterparts (P < 0.05). Intake of hay (W-corrected) was higher for Young compared with Old steers without supplement but was variably reduced for both steer groups with increasing supplement intake. The results of these experiments have implications for supplement formulation for steers at different stages of maturity grazing low-quality forages
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