Exact dynamics of a reaction-diffusion model with spatially alternating rates

We present the exact solution for the full dynamics of a nonequilibrium spin chain and its dual reaction-diffusion model, for arbitrary initial conditions. The spin chain is driven out of equilibrium by coupling alternating spins to two thermal baths at different temperatures. In the reaction-diffusion model, this translates into spatially alternating rates for particle creation and annihilation, and even negative ``temperatures'' have a perfectly natural interpretation. Observables of interest include the magnetization, the particle density, and all correlation functions for both models. Two generic types of time-dependence are found: if both temperatures are positive, the magnetization, density and correlation functions decay exponentially to their steady-state values. In contrast, if one of the temperatures is negative, damped oscillations are observed in all quantities. They can be traced to a subtle competition of pair creation and annihilation on the two sublattices. We comment on the limitations of mean-field theory and propose an experimental realization of our model in certain conjugated polymers and linear chain compounds.Comment: 13 pages, 1 table, revtex4 format (few minor typos fixed). Published in Physical Review

Fatias de banana liofilizadas como veículo probiótico: Influência da matriz de revestimento na sobrevivência e estabilidade dos probióticos

O mercado mundial de snacks (petiscos) com apelo de saudabilidade movimenta bilhões de dólares todos os anos. Dessa forma, este trabalho visou produzir fatias liofilizadas de banana como veículos de probióticos, a fim de investigar o efeito de diferentes matrizes polissacarídicas de revestimento na sobrevivência das cepas bacterianas Bacillus coagulans (esporogênica) e Lactobacillus acidophilus (não esporogênica) à secagem por liofilização e sua estabilidade durante o armazenamento. As cepas bacterianas foram compradas da empresa italiana Sacco (B. coagulans BC4 50 MLD, lote C235515A; L. acidophilus LA-3, lote C236623A). Foram preparadas três formulações para veicular os probióticos: celulose bacteriana (CB, combinada a carboximetilcelulose sódica - CMC ? à proporção 5:1 CB/CMC e homogeneizada em água destilada utilizando Ultra-Turrax a 16000 rpm); amido de milho (suspenso em água destilada estéril a 20% m/V, mantido em agitação e aquecido a 90ºC por 45 min para gelatinização); e água destilada estéril (sem matriz) como controle. A CB foi fornecida pela Biosmart Nanotecnologia (Araraquara, SP), produzida pela bactéria Komagataeibacter rhaeticus. Após o preparo das formulações, adicionou-se a elas uma das culturas bacterianas em quantidade calculada para garantir uma concentração de 8 log ufc/mL. A cultura estoque de B. coagulans liofilizada foi diretamente incorporada às formulações, já a cultura estoque de L. acidophilus foi previamente ativada em meio MRS. Bananas da variedade nanica foram cortadas em fatias de aproximadamente 5 mm, branqueadas em solução de ácido cítrico a 1% em ebulição por 1 min e, então, imersas em uma das formulações probióticas por 1 min. As fatias foram, por fim, congeladas a -25ºC por 24 h e liofilizadas por 6 dias. Resultados preliminares mostram que todas as formulações probióticas garantiram às fatias de banana uma boa concentração de probióticos pré liofilização (pelo menos 7 log UFC/g), sendo que a bactéria B. coagulans apresentou a melhor taxa de sobrevivência ao processo de secagem sem muita influência da matriz polissacarídica. Ainda é necessário analisar a estabilidade dos probióticos à armazenagem e realizar o teste de aceitação sensorial

Organic and mineral matter changes due to oil generation, saturation and expulsion processes based on artificial maturation experiments

Hydrous pyrolysis experiments were conducted on immature organic-rich rock with type-I kerogen to evaluate petroleum generation, saturation and expulsion processes. The experiments were carried out under isothermal conditions at ten different temperatures (280° through 360°C) for nine different time spans between 18 and 144h. Rock samples recovered from the experiments were analyzed for total organic carbon (TOC-weight%), Rock-Eval pyrolysis, vitrinite reflectance (Ro%), spectral fluorescence and visual characterization of organic matter under the microscopy. TOC, S2 and HI tend to decrease with increasing temperature and duration of the experiments as expected. The Ro% values reach up to 1.14% in the most severe experiment (i.e. 360°C/96h). The Ro% is believed to be suppressed due to hydrogen incorporation from bitumen. The bitumen production was observed with the increase of transformation index (TI) and two types of bitumen were differentiated by fluorescence color. The bitumen with yellow fluorescence was mainly composed of saturate and aromatic hydrocarbons that were probably generated earlier than the bitumen with brown fluorescence which is rich in NSO compounds. The greatest bitumen saturation occurs at TI around of 41% to 45%, when the S1 reaches its highest values. The decrease of bitumen saturation and consequent oil expulsion is marked by a reduction in S1 values and fluorescence color. This phenomenon occurs simultaneously with the development of fractures and voids in the mineral matrix which reduces the oil retention capability and facilitates the expulsion process. These observations enhanced the understanding of oil generation and saturation processes, as well as primary migration, expulsion and type of generated bitumen

Organic and mineral matter changes due to oil generation, saturation and expulsion processes based on artificial maturation experiments

Hydrous pyrolysis experiments were conducted on immature organic-rich rock with type-I kerogen to evaluate petroleum generation, saturation and expulsion processes. The experiments were carried out under isothermal conditions at ten different temperatures (280° through 360°C) for nine different time spans between 18 and 144h. Rock samples recovered from the experiments were analyzed for total organic carbon (TOC-weight%), Rock-Eval pyrolysis, vitrinite reflectance (Ro%), spectral fluorescence and visual characterization of organic matter under the microscopy. TOC, S2 and HI tend to decrease with increasing temperature and duration of the experiments as expected. The Ro% values reach up to 1.14% in the most severe experiment (i.e. 360°C/96h). The Ro% is believed to be suppressed due to hydrogen incorporation from bitumen. The bitumen production was observed with the increase of transformation index (TI) and two types of bitumen were differentiated by fluorescence color. The bitumen with yellow fluorescence was mainly composed of saturate and aromatic hydrocarbons that were probably generated earlier than the bitumen with brown fluorescence which is rich in NSO compounds. The greatest bitumen saturation occurs at TI around of 41% to 45%, when the S1 reaches its highest values. The decrease of bitumen saturation and consequent oil expulsion is marked by a reduction in S1 values and fluorescence color. This phenomenon occurs simultaneously with the development of fractures and voids in the mineral matrix which reduces the oil retention capability and facilitates the expulsion process. These observations enhanced the understanding of oil generation and saturation processes, as well as primary migration, expulsion and type of generated bitumen

Study of genetic varibility of reproductive traits in Nellore bulls

Heritabilities, were estimated of testicular traits, semen quality and libido in Nellore bulls. Records on 438 bulls registered from 1992 to 1997 were analyzed by single trait MTDFREML methodology using the animal model. The estimates obtained of heritability unadjusted and adjusted for body weight and the respective standard errors were: for scrotal circumference (0.81 ± 0.04 and 0.71 ± 0.07); testicular consistency (0.17 ± 0.09 and 0.17 ± 0.10); right testes length (0.42 ± 0.10 and 0.31 ± 0.11); left testes length (0.38 ± 0.10 and 0.30 ± 0.10); right testes width (0.78 ± 0.05 and 0.38 ± 0.12); left testes width (0.78 ± 0.05 and 0.34 ± 0.13); testicular volume (0.50 ± 0.09 and 0.30 ± 0.10); semen volume (0.20 ± 0.10 and 0.20 ± 0.10); sperm motility (0.15 ± 0.11 and 0.15±.11); sperm vigor (0.55 ± 0.10 and 0.54 ± 0.10); gross motility (0.07 ± 0.4 and 0.06 ± 0.4); major defects (0.59 ± 0.09 and 0.51 ± 0.11); minor defects (0.21 ±0.13 and 0.13 ± 0.11); total sperm defects (0.58 ± 0.09 and 0.48 ± 0.12) and libido (0.34 ± 0.10 and 0.19 ± 0.11)

Monitorización de la frecuencia cardíaca en las labores de extinción de incendios forestales, para la prevención de riesgos laborales

P. 6-26Ante la previsión de aumento de incendios forestales en la zona meditarránea,TRAGSA y la Fraternidad Muprespa analizan los aspectos derivados de la frecuencia cardiaca en las labores de extinción de incendios forestales. El trabajo físico del personal especialista en extinción de incendios forestales durante la extinción de incendios se realiza a una intensidad de esfuerzo que es lo suficientemente alta como para conllevar un elevado coste energético, y que se corresponde a una carga de trabajo que requiere y exige una buena condición física para afrontarla con las suficientes garantías y con el menor riesgo para la salud.N

A new era for the South African Journal of Sports Medicine

A new era for the South African Journal of Sports Medicin

Organic and mineral matter changes due to oil generation, saturation and expulsion processes based on artificial maturation experiments

Hydrous pyrolysis experiments were conducted on immature organic-rich rock with type-I kerogen to evaluate petroleum generation, saturation and expulsion processes. The experiments were carried out under isothermal conditions at ten different temperatures (280° through 360°C) for nine different time spans between 18 and 144h. Rock samples recovered from the experiments were analyzed for total organic carbon (TOC–weight%), Rock-Eval pyrolysis, vitrinite reflectance (Ro%), spectral fluorescence and visual characterization of organic matter under the microscopy. TOC, S2 and HI tend to decrease with increasing temperature and duration of the experiments as expected. The Ro% values reach up to 1.14% in the most severe experiment (i.e. 360°C/96h). The Ro% is believed to be suppressed due to hydrogen incorporation from bitumen. The bitumen production was observed with the increase of transformation index (TI) and two types of bitumen were differentiated by fluorescence color. The bitumen with yellow fluorescence was mainly composed of saturate and aromatic hydrocarbons that were probably generated earlier than the bitumen with brown fluorescence which is rich in NSO compounds. The greatest bitumen saturation occurs at TI around of 41% to 45%, when the S1 reaches its highest values. The decrease of bitumen saturation and consequent oil expulsion is marked by a reduction in S1 values and fluorescence color. This phenomenon occurs simultaneously with the development of fractures and voids in the mineral matrix which reduces the oil retention capability and facilitates the expulsion process. These observations enhanced the understanding of oil generation and saturation processes, as well as primary migration, expulsion and type of generated bitumen