1,183 research outputs found

    Symplectic evolution of Wigner functions in markovian open systems

    Full text link
    The Wigner function is known to evolve classically under the exclusive action of a quadratic hamiltonian. If the system does interact with the environment through Lindblad operators that are linear functions of position and momentum, we show that the general evolution is the convolution of the classically evolving Wigner function with a phase space gaussian that broadens in time. We analyze the three generic cases of elliptic, hyperbolic and parabolic Hamiltonians. The Wigner function always becomes positive in a definite time, which is shortest in the hyperbolic case. We also derive an exact formula for the evolving linear entropy as the average of a narrowing gaussian taken over a probability distribution that depends only on the initial state. This leads to a long time asymptotic formula for the growth of linear entropy.Comment: this new version treats the dissipative cas

    Poincare's Recurrence Theorem and the Unitarity of the S matrix

    Full text link
    A scattering process can be described by suitably closing the system and considering the first return map from the entrance onto itself. This scattering map may be singular and discontinuous, but it will be measure preserving as a consequence of the recurrence theorem applied to any region of a simpler map. In the case of a billiard this is the Birkhoff map. The semiclassical quantization of the Birkhoff map can be subdivided into an entrance and a repeller. The construction of a scattering operator then follows in exact analogy to the classical process. Generically, the approximate unitarity of the semiclassical Birkhoff map is inherited by the S-matrix, even for highly resonant scattering where direct quantization of the scattering map breaks down.Comment: 4 latex pages, 5 ps figure

    Using silvopastoral systems for the mitigation of greenhouse gas emissions from livestock in the Colombian Amazon

    Get PDF
    Silvopastoral systems (SPS) are strategic in neutralizing greenhouse gases (GHG) emissions in livestock production systems, particularly in the tropics. This research assessed the mitigation potential of SPS on the carbon footprint (CFP) neutralizing in one integrated livestock farm of cow-calf and pig production system in the Colombian Amazon. Annual carbon accumulation rate (ACAR) in MgCO2e ha− 1y−1, was evaluated on living above-ground biomass including trees and shrubs > 2 cm DBH and pasture, and leaf litter and below-ground biomass including coarse and fine roots, soil organic carbon 0–10 cm deep, and total ACAR adding up all components in live fences (LF), scattered trees (ST), fallows (FW), fodder bank (FB) and pastures (PT). The GHG emissions in MgCO2e ha− 1y−1 were accounted in CO2 from liming, urea, fuel, electricity, and supplementation, CH4 from enteric methane, manure, and organic fertilization and N2O from urine and manure. The C balance was obtained from the differences between ACAR of SPS on farm and the CFP per surface. Mean total ACAR expressed in MgC ha− 1y−1 were 9.0 ± 4.6 in FW, 7.0 ± 1.2 in LF, 5.5 ± 0.8 in ST, 4.2 ± 0.2 in FB and 2.9 ± 0.1 in PT. Mean CFP was 3.7 MgCO2e ha− 1y−1, 5.3 MgCO2e Live Weight ha− 1y−1, and 23.6 MgCO2e Live Weight Gain y− 1. The CFP (area) can be neutralized with total ACAR value of 2.1 ha− 1 for LF, 1.6 ha− 1 for FW, 2.6 ha− 1 for ST, 3.5 ha− 1 for FB and 5.1 ha− 1 for PT. The Silvopastoral systems have a higher potential for neutralizing GHG emissions than pasture-based scenario when considering the ACAR in above-ground biomass.info:eu-repo/semantics/publishedVersio

    Prevalência da exposição ao fumo ambiental do tabaco em casa e do tabagismo na população Portuguesa – o estudo INAsma

    Get PDF
    ResumoIntroduçãoNeste estudo, pretendemos: 1) estimar a prevalência, na população portuguesa, da exposição ao fumo ambiental do tabaco em casa; 2) estimar a prevalência de tabagismo em Portugal; 3) identificar as características sociais e pessoais associadas ao tabagismo ou à exposição ao fumo ambiental do tabaco.MétodosEstudo transversal consistindo na aplicação, à população, a nível nacional, de questionário telefónico. Completaram a entrevista 6 003 indivíduos. A exposição ao fumo ambiental do tabaco em casa foi definida como a exposição, em casa, ao fumo do tabaco de, pelo menos, um fumador atual. Por fumador entendeu-se um indivíduo com ≥ 15 anos que fumou, pelo menos, um cigarro por dia durante um período de um ano; um fumador atual fumou no último mês.ResultadosReferiram exposição ao fumo ambiental do tabaco em casa 26,6% dos participantes (IC 95%: 25,5-27,7). Viver num agregado familiar constituído por ≥ 4 pessoas (OR=2,31; IC 95%: [1,81-2,96]), ser fumador atual (OR=7,29; IC 95%: [5,74-9,26]) ou ter asma atual (OR=2,06; IC 95%: [1,45-2,94]) associaram-se positivamente à exposição ao fumo ambiental do tabaco. Na análise estratificada por sexo, o efeito da asma atual manteve-se apenas nas mulheres.Atualmente, 19,0% (IC 95%: 18,0-20,0) da população portuguesa é fumadora e 17,2% (IC 95%: 16,2-18,2) são ex-fumadores. A prevalência de fumadores atuais é mais elevada nos homens do que nas mulheres (26,5 versus 12,2%, p<0,001). A probabilidade de ser um fumador atual foi maior nos homens, nas pessoas mais instruídas e nos indivíduos expostos, em casa, ao fumo ambiental do tabaco. Na análise estratificada por sexo, o efeito da escolaridade manteve-se apenas nas mulheres.ConclusãoA exposição ao fumo ambiental do tabaco em casa foi mais elevada do que a anteriormente publicada. Crianças/adolescentes e doentes com asma podem ter um risco de exposição ambiental mais elevado. Este estudo apoia uma tendência decrescente da prevalência de tabagismo nos homens portugueses, mas uma tendência crescente nas mulheres.AbstractBackgroundWe aimed to: 1) estimate the prevalence of exposure to environmental tobacco smoke (ETS) at home in the Portuguese population; 2) estimate tobacco smoking prevalence in Portugal; 3) identify social and personal characteristics associated with smoking or exposure to ETS.MethodsNationwide, cross-sectional, population-based telephone survey. Overall, 6003 individuals completed the interview. ETS exposure at home was defined as exposure to at least one current smoker at home. A smoker was defined as someone with 15 years or older, smoking at least 1 cigarette per day during a year; a current smoker (CS) smoked in the last month.ResultsExposure to ETS at home was reported by 26.6% (95%CI 25.5-27.7) of the participants. Living in households with ≥4 persons (OR=2.31; 95%CI[1.81-2.96]), being a current smoker (OR=7.29; 95%CI[5.74-9.26]) or having current asthma (OR=2.06; 95%CI[1.45-2.94]) were factors positively associated with ETS exposure. When analyzed by gender, the effect of current asthma was only relevant to females.Currently 19.0% (95%CI 18.0-20.0) of the Portuguese population smokes tobacco and 17.2% (95%CI 16.2-18.2) are ex-smokers. CS prevalence is higher in males than females (26.5%versus 12.2%, p<0,001). The odds of being a CS were higher for males, the more educated, and those exposed to ETS at home. When analyzed by gender, school education only affected females.ConclusionExposure to ETS at home was higher than previously reported. Children/adolescents and asthma patients may have a higher risk of exposure. This report endorses a decreasing trend in the prevalence of tobacco smoking in Portuguese males, but a tendency to increase in females

    Biologia floral, reprodutiva e propagação vegetativa de baunilha

    Get PDF
    Vanilla chamissonis is a species of orchid naturally occurring in the coastal strips of the state of S&atilde;o Paulo (Brazil), with high economic interest. However, sustainable management of natural stands aiming for commercial production of fruit is not put into practice. This&nbsp; study aims to describe some aspects of the floral biology, reproductive biology and vegetative propagation of natural stands of Vanilla chamissonis, aiming to generate information for its sustainable management. For&nbsp; studies of floral biology, the anthesis and senescence of flowers in daytime and nighttime periods, as well as pollinators, were monitored.&nbsp; For studies of reproductive biology, the following treatments were examined: T1-control (no intervention), T2-manual self-pollination/induced autogamy, T3-artificial cross-pollination/induced allogamy, T4-spontaneous self-pollination/autogamy, and T5-natural cross-pollination/allogamy. For studies of&nbsp; vegetative propagation, the lower portion of the cuttings was treated with indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA), both applied in paste at 3,000 mg L-1. Sustainable management of vanilla has the required attributes to application by the local community. Direct observation of flowers from anthesis until senescence was adequate, but it was not possible to determine the agents responsible for pollination. Cross-pollination is the most appropriate for management aiming for the commercial production of fruit.&nbsp; The use of IBA resulted in the greatest number of terrestrial roots.A esp&eacute;cie Vanilla chamissonis&nbsp; &eacute; uma orqu&iacute;dea de ocorr&ecirc;ncia natural nas restingas do Estado de S&atilde;o Paulo&nbsp; com elevado&nbsp; interesse econ&ocirc;mico, contudo, o manejo sustentado dos povoamentos naturais visando a produ&ccedil;&atilde;o comercial de seus frutos n&atilde;o &eacute; praticado. O presente trabalho objetiva, descrever aspectos da biologia floral, reprodutiva e propaga&ccedil;&atilde;o vegetativa de povoamentos naturais de&nbsp; Vanilla chamissonis, visando informa&ccedil;&otilde;es &uacute;teis para seu o manejo sustentado. Para estudos da biologia floral, monitorou-se o per&iacute;odo da antese at&eacute;&nbsp; a&nbsp;&nbsp; senesc&ecirc;ncia das flores nos per&iacute;odos diurnos e noturnos, e a presen&ccedil;a de agentes polinizadores. Para o estudo da biologia reprodutiva, avaliaram-se os tratamentos: T1-testemunha (sem interven&ccedil;&atilde;o), T2-autopoliniza&ccedil;&atilde;o manual/autogamia induzida, T3-poliniza&ccedil;&atilde;o artificial cruzada/alogamia induzida, T4-autopoliniza&ccedil;&atilde;o espont&acirc;nea/autogamia e T5-poliniza&ccedil;&atilde;o natural cruzada/alogamia. Para a propaga&ccedil;&atilde;o vegetativa, a por&ccedil;&atilde;o inferior das estacas foi tratada com &aacute;cido indolac&eacute;tico (AIA) e &aacute;cido indolbut&iacute;rico (AIB), ambos aplicados em pasta &agrave; 3.000 mg L-1. O manejo sustentado da baunilha possui atributos necess&aacute;rios a condu&ccedil;&atilde;o pela comunidade local. A observa&ccedil;&atilde;o direta das flores desde a antese at&eacute; a senesc&ecirc;ncia foi adequada, contudo n&atilde;o foi poss&iacute;vel determinar os agentes respons&aacute;veis pela&nbsp; poliniza&ccedil;&atilde;o. A poliniza&ccedil;&atilde;o cruzada &eacute; a mais adequada para o manejo visando a produ&ccedil;&atilde;o comercial de frutos. O emprego do AIB apresentou maior n&uacute;mero de ra&iacute;zes terrestres

    Neuroimmunomodulatory and neuroprotective effects of the flavonoid apigenin in in vitro models of neuroinflammation associated with Alzheimer's disease

    Get PDF
    Neurodegenerative disorders (ND) are characterized by the progressive and irreversible loss of neurons. Alzheimer’s Disease (AD) is the most incident age-related ND, in which the presence of a chronic inflammatory compound seems to be related to its pathogenesis. Different stimuli in the central nervous system (CNS) can induce activation, proliferation, and changes in phenotype and glial function, which can be modulated by anti-inflammatory agents. Apigenin (4,5,7–trihydroxyflavone) is a flavonoid found in abundance in many fruits and vegetables, that has shown important effects upon controlling the inflammatory response. This study evaluated the neuroprotective and neuroimmunomodulatory potential of apigenin using in vitro models of neuroinflammation associated with AD. Co-cultures of neurons and glial cells were obtained from the cortex of newborn and embryonic Wistar rats. After 26 days in vitro, cultures were exposed to lipopolysaccharide (LPS; 1 μg/ml), or IL-1β (10 ng/ml) for 24 h, or to Aβ oligomers (500 nM) for 4 h, and then treated with apigenin (1 μM) for further 24 h. It was observed that the treatment with apigenin preserved neurons and astrocytes integrity, determined by Rosenfeld’s staining and immunocytochemistry for β-tubulin III and GFAP, respectively. Moreover, it was observed by Fluoro-Jade-B and caspase-3 immunostaining that apigenin was not neurotoxic and has a neuroprotective effect against inflammatory damage. Additionally, apigenin reduced microglial activation, characterized by inhibition of proliferation (BrdU+ cells) and modulation of microglia morphology (Iba-1 + cells), and decreased the expression of the M1 inflammatory marker CD68. Moreover, as determined by RT-qPCR, inflammatory stimuli induced by IL-1β increased the mRNA expression of IL-6, IL-1β, and CCL5, and decreased the mRNA expression of IL-10. Contrary, after treatment with apigenin in inflammatory stimuli (IL-1β or LPS) there was a modulation of the mRNA expression of inflammatory cytokines, and reduced expression of OX42, IL-6 and gp130. Moreover, apigenin alone and after an inflammatory stimulus with IL-1β also induced the increase in the expression of brain-derived neurotrophic factor (BDNF), an effect that may be associated with anti-inflammatory and neuroprotective effects. Together these data demonstrate that apigenin presents neuroprotective and anti-inflammatory effects in vitro and might represent an important neuroimmunomodulatory agent for the treatment of neurodegenerative conditions

    Performance And Economic Analysis Of Finished Lambs In Feedlot

    Get PDF
    This study aimed to evaluate animal performance and economic performance of feedlot crossbred lambs (Santa Inês+ - Suffolk) fed different diets based on hay from Cynodon dactylon genotypes, through the use of financial measures considering only the period of feedlot, without relating it to the complete management cycle. A total of 30 intact crossbred Suffolk lambs, identified with earrings, with an average age of 90 days and an average body weight of 21.5 kg were used in this study. Diets were formulated using as treatments a standard concentrate and hay of the Cynodon dactylon genotypes Jiggs, Vaquero, Tifton 68, Coast-Cross, Tifton 85 and Russell in a 60:40 forage-to-concentrate ratio. The treatments were distributed in a randomized complete block design with five replicates. There were significant differences between diets in terms of total expenditure on food, and the highest values were obtained for the Jiggs genotype (BRL 48.96/animal). The animals fed diets based on Tifton 68 hay had a higher rate of return (2.16%) and profitability (34.63%) compared to the other diets. The use of diets based on Tifton 68 hay for feedlot lambs in the finishing phase brings higher economic returns compared to the remaining diets.37129330

    Characteristic Time and Maximum Mixedness: Single Mode Gaussian States in Dissipative Channels

    Full text link
    We derive an upper limit for the mixedness of single bosonic mode gaussian states propagating in dissipative channels. It is a function of the initial squeezing and temperature of the channel only. Moreover the time at which von Neumann's entropy reaches its maximum value coincides with that of complete loss of coherence, thus defining a quantum-classical transition.Comment: Accepted versio

    A new heparan sulfate from the mollusk nodipecten nodosus inhibits merozoite invasion and disrupts rosetting and cytoadherence of plasmodium falciparum

    Get PDF
    Despite treatment with effective antimalarial drugs, the mortality rate is still high in severe cases of the disease, highlighting the need to find adjunct therapies that can inhibit the adhesion of Pf-iEs. In this context, we evaluated a new heparan sulfate (HS) from Nodipecten nodosus for antimalarial activity and inhibition of P. falciparum cytoadhesion and rosetting. Parasite inhibition was measured by SYBR green using a cytometer. HS was assessed in rosetting and cytoadhesion assays under static and flow conditions using CHO and HLEC cells expressing ICAM1 and CSA, respectively. This HS inhibited merozoite invasion similar to heparin. Moreover, mollusk HS decreased cytoadherence of P. falciparum to CSA (chondroitin sulfate A) and ICAM-1 (intercellular adhesion molecule-1) on the surface of endothelial cells under static and flow conditions. In addition, this glycan efficiently disrupted rosettes. These findings support a potential use for mollusk HS as adjunct therapy for severe malaria114CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQFUNDAÇÃO CARLOS CHAGAS FILHO DE AMPARO À PESQUISA DO ESTADO DO RIO DE JANEIRO - FAPERJFUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESPnão temnão tem2012/16525-2; 2017/18611-7; 2010/18571-6; 2015/20774-

    The flavonoid agathisflavone modulates the microglial neuroinflammatory response and enhances remyelination

    Get PDF
    Myelin loss is the hallmark of the demyelinating disease multiple sclerosis (MS) and plays a significant role in multiple neurodegenerative diseases. A common factor in all neuropathologies is the central role of microglia, the intrinsic immune cells of the central nervous system (CNS). Microglia are activated in pathology and can have both pro- and anti-inflammatory functions. Here, we examined the effects of the flavonoid agathisflavone on microglia and remyelination in the cerebellar slice model following lysolecithin induced demyelination. Notably, agathisflavone enhances remyelination and alters microglial activation state, as determined by their morphology and cytokine profile. Furthermore, these effects of agathisflavone on remyelination and microglial activation were inhibited by blockade of estrogen receptor α. Thus, our results identify agathisflavone as a novel compound that may act via ER to regulate microglial activation and enhance remyelination and repair
    corecore