5,080 research outputs found

    Soliton model for proton conductivity in Langmuir films

    Get PDF
    A soliton model for proton conductivity in Langmuir films is presented. The model contains three real scalar fields describing the hydrogen involved in the conduction, the hydrophilic head of the Langmuir film, and the water. Soliton solutions that describe proton motion along the hydrogen bonds are found. Under compression of the film, the distance between the minima of the proton potential and the strength of the hydrogen bonds between the film molecule and the water are changed. Such changes increase the probability of soliton creation. The model presented allows proton conductivity data in Langmuir films to be explained.Comment: Revtex, 07 pages, 2 eps figures, to be published in Chem. Phys. Let

    Kinetics of TNF-alpha and IFN-gamma mRNA expression in islets and spleen of NOD mice

    Get PDF
    Insulin-dependent diabetes mellitus is caused by autoimmune destruction of pancreatic ß cells. Non-obese diabetic (NOD) mice spontaneously develop diabetes similar to the human disease. Cytokines produced by islet-infiltrating mononuclear cells may be directly cytotoxic and can be involved in islet destruction coordinated by CD4+ and CD8+ cells. We utilized a semiquantitative RT-PCR assay to analyze in vitro the mRNA expression of TNF-alpha and IFN-gamma cytokine genes in isolated islets (N = 100) and spleen cells (5 x 10(5) cells) from female NOD mice during the development of diabetes and from female CBA-j mice as a related control strain that does not develop diabetes. Cytokine mRNAs were measured at 2, 4, 8, 14 and 28 weeks of age from the onset of insulitis to the development of overt diabetes. An increase in IFN-gamma expression in islets was observed for females aged 28 weeks (149 ± 29 arbitrary units (AU), P<0.05, Student t-test) with advanced destructive insulitis when compared with CBA-j mice, while TNF-alpha was expressed in both NOD and CBA-j female islets at the same level at all ages studied. In contrast, TNF-alpha in spleen was expressed at higher levels in NOD females at 14 weeks (99 ± 8 AU, P<0.05) and 28 weeks (144 ± 17 AU, P<0.05) of age when compared to CBA-j mice. The data suggest that IFN-gamma and TNF-alpha expression in pancreatic islets of female NOD mice is associated with ß cell destruction and overt diabetes.1347135

    The importance of acoustic background modelling in CNN-based detection of the neotropical White-lored Spinetail (Aves, Passeriformes, Furnaridae)

    Get PDF
    Machine learning tools are widely used in support of bioacoustics studies, and there are numerous publications on the applicability of convolutional neural networks (CNNs) to the automated presence-absence detection of species. However, the relation between the merit of acoustic background modelling and the recognition performance needs to be better understood. In this study, we investigated the influence of acoustic background substance on the performance of the acoustic detector of the White-lored Spinetail (Synallaxis albilora). Two detector designs were evaluated: the 152-layer ResNet with transfer learning and a purposely created CNN. We experimented with acoustic background representations trained with season-specific (dry, wet, and all-season) data and without explicit modelling to evaluate its influence on the detection performance. The detector permits monitoring of the diel behaviour and breeding time of White-lored Spinetail solely based on the changes in the vocal activity patterns. We report an advantageous performance when background modelling is used, precisely when trained with all-season data. The highest classification accuracy (84.5%) was observed for the purposely created CNN model. Our findings contribute to an improved understanding of the importance of acoustic background modelling, which is essential for increasing the performance of CNN-based species detectors.This work was supported by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior – Brazil (CAPES) under Grant [CAPES-01]; Instituto Nacional de Ciência e Tecnologia em Áreas Úmidas (INAU/UFMT/CNPq); Centro de Pesquisa do Pantanal (CPP); and Brehm Funds for International Bird Conservation (BF), Germany

    Reação de genótipos de feijão-caupi a Fusarium oxysporum f. sp. tracheiphilum, Rhizoctonia solani e Sclerotium rolfsii.

    Get PDF
    Os patógenos habitantes do solo Fusarium oxysporum f.sp. tracheiphilum, Rhizoctonia solani e Sclerotium rolfsii infectam o feijão-caupi e causam redução na sua produtividade. Considerando que, a adoção de cultivares resistentes a estes patógenos constitui-se numa das medidas de controle mais viáveis, este trabalho teve como objetivo avaliar a reação de genótipos de feijão-caupi a estes três patógenos radiculares F. oxysporum f.sp. tracheiphilum, R. solani e S.rolfsii. Os ensaios foram conduzidos sob condições de casa de vegetação e os 36 genótipos de feijão-caupi foram avaliados quanto à resistência a R. solani e S.rolfsii pelo método da infestação do solo com o inóculo dos respectivos patógenos. Já para avaliação de F. oxysporum f.sp. tracheiphilum os genótipos de feijão-caupi foram imersos numa suspensão do patógeno. A testemunha consistiu de plantas não inoculadas com os patógenos

    Growth performance, in vitro antioxidant properties and chemical composition of the halophyte Limonium algarvense Erben are strongly influenced by the irrigation salinity

    Get PDF
    Limonium algarvense Erben (sea lavender) is a halophyte species with potential to provide natural ingredients with in vitro antioxidant, anti-inflammatory, neuroprotective and antidiabetic properties. This study reports for the first time the 1) cultivation of sea lavender in greenhouse conditions under irrigation with freshwater (approx. 0 mM NaCl) and saline aquaculture wastewater (300 and 600 mM NaCl), and 2) the influence of the irrigation salinity on the plant performance (e.g growth, number of produced leaves and flowers), in vitro antioxidant properties [radical scavenging activity (DPPH and ABTS), ferric reducing antioxidant power (FRAP), metal chelating properties on copper (CCA) and iron (ICA)], toxicity (in vitro on three mammalian cell lines) and chemical composition (determined by LC-ESI-HRMS/MS). The freshwater-irrigated plants had better growth performance than those irrigated with saltwater. Extracts from wild plants, had the highest antioxidant activity, but those from cultivated ones kept high in vitro antioxidant properties and interesting chemical profile. The flowers' extracts of plants irrigated with 300 mM NaCl had the highest antioxidant activities against DPPH, whereas those from freshwater-irrigated plants were more active on ABTS, CCA and FRAP. Most of the extracts showed nil toxicity. The flowers' extracts displayed the highest diversity of compounds, mainly quercetin, apigenin, luteolin, naringenin and their glycoside derivatives. Moreover, their abundance varied with the irrigation salinity. These data indicate that sea lavender plants can be successfully cultivated in greenhouse conditions under fresh- and saltwater irrigation, maintaining interesting biological and chemical properties.Funding Agency Portuguese Foundation for Science and Technology Portuguese National Budget CCMAR/Multi/04326/2019 GreenVet project ALG-01-0145-FEDER-028876 XtrerneAquaCrops FA-05-2017-028 Lisboa-01-0145-FEDER-022125-RNEM-IST ID/QUI/00100/201 Portuguese Foundation for Science and Technology SFRH/BD/116604/2016 CEECIND/00425/2017info:eu-repo/semantics/publishedVersio

    Mutual heavy ion dissociation in peripheral collisions at ultrarelativistic energies

    Get PDF
    We study mutual dissociation of heavy nuclei in peripheral collisions at ultrarelativistic energies. Earlier this process was proposed for beam luminosity monitoring via simultaneous registration of forward and backward neutrons in zero degree calorimeters at Relativistic Heavy Ion Collider. Electromagnetic dissociation of heavy ions is considered in the framework of the Weizsacker-Williams method and simulated by the RELDIS code. Photoneutron cross sections measured in different experiments and calculated by the GNASH code are used as input for the calculations of dissociation cross sections. The difference in results obtained with different inputs provides a realistic estimation for the systematic uncertainty of the luminosity monitoring method. Contribution to simultaneous neutron emission due to grazing nuclear interactions is calculated within the abrasion model. Good description of CERN SPS experimental data on Au and Pb dissociation gives confidence in predictive power of the model for AuAu and PbPb collisions at RHIC and LHC.Comment: 46 pages with 7 tables and 13 figures, numerical integration accuracy improved, next-to-leading-order corrections include
    corecore