432 research outputs found

    Note on the point-splitting procedure to evaluate vacuum fluctuation in certain cylindrically symmetric backgrounds

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    We revisit two-point function approaches used to study vacuum fluctuation in wedge-shaped regions and conical backgrounds. Appearance of divergent integrals is discussed and circumvented. The issue is considered in the context of a massless scalar field in cosmic string spacetime.Comment: REVTeX file, 7 page

    Antimicrobial Photodynamic Therapy for the Treatment of Teeth with Apical Periodontitis: A Histopathological Evaluation

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    Introduction: This study evaluated the in vivo response of apical and periapical tissues of dogs' teeth with apical periodontitis after one-session endodontic treatment with and without antimicrobial photodynamic therapy (aPDT). Methods: Sixty root canals with experimentally induced apical periodontitis were instrumented and assigned to 4 groups receiving aPDT and root canal filling (RCF) or not: group aPDT+/RCF- (n = 20): aPDT (photosensitizer phenothiazine chloride at 10 mg/mL for 3 minutes and diode laser [2 = 660 nm, 60 mW/cm(2)] for 1 minute) and RCF in the same session; group aPDT+/RCF (n = 10); group aPDT /RCF+ (n = 20), and group aPDT /RCF (n = 10). Teeth were restored, and the animals were killed after 90 days. Sections from the maxillas and mandibles were stained with hematoxylin-eosin and Mallory trichrome and examined under light microscopy. Descriptive (ie, newly formed apical mineralized tissue, periapical inflammatory infiltrate, apical periodontal ligament thickness, and mineralized tissue resorption) and quantitative (ie, periapical lesion size and number of inflammatory cells) microscopic analysis was performed. Quantitative data were analyzed by the Kruskal-Wallis and Dunn tests (alpha =.05). Results: In the aPDT-treated groups, the periapical region was moderately/severely enlarged with no inflammatory cells, moderate neoangiogenesis and fibrogenesis, and the smallest periapical lesions. Conclusions: Although apical closure by mineralized tissue deposition was not achieved, the absence of inflammatory cells, moderate neoangiogenesis, and fibrogenesis in the periapical region in the groups treated with aPDT indicate that this can be a promising adjunct therapy to cleaning and shaping procedures in teeth with apical periodontitis undergoing one-session endodontic treatment. (J Endod 2012;38:360-366

    Aspects of classical and quantum motion on a flux cone

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    Motion of a non-relativistic particle on a cone with a magnetic flux running through the cone axis (a ``flux cone'') is studied. It is expressed as the motion of a particle moving on the Euclidean plane under the action of a velocity-dependent force. Probability fluid (``quantum flow'') associated with a particular stationary state is studied close to the singularity, demonstrating non trivial Aharonov-Bohm effects. For example, it is shown that near the singularity quantum flow departs from classical flow. In the context of the hydrodynamical approach to quantum mechanics, quantum potential due to the conical singularity is determined and the way it affects quantum flow is analysed. It is shown that the winding number of classical orbits plays a role in the description of the quantum flow. Connectivity of the configuration space is also discussed.Comment: LaTeX file, 21 pages, 8 figure

    Improvement in the Adsorption of Anionic and Cationic Dyes From Aqueous Solutions: A Comparative Study Using Aluminium Pillared Clays and Activated Carbon

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    The aim of this work was to evaluate the adsorption properties of anionic dye Reactive Black 5 (RB5) and cationic dye Methylene Blue (MB) from salted aqueous solution using natural clay, aluminum pillared clay (Al-PILC), and activated carbon. The textural properties of the materials were obtained by N2 adsorption at 77 K and the structural properties of natural and pillared clays were determined by X-ray diffraction. The effect of pH, contact time, initial concentration of dye, and influence of the addition of NaCl were evaluated by batch adsorption. Adsorption isotherms of Al-PILC, in different salt concentration were compared with natural clay and activated carbon. The adsorption isotherms were well fitted by the Langmuir and Langmuir-Freundlich models. The process of pillaring only improved the adsorption of the anionic dye RB5. Depending on the system adsorbent/adsorbate analyzed, the salt concentration can either help or hinder dye adsorption. We found that a special morphology formed during the process of pillaring greatly increased adsorption of the MB cationic dye in the range of high salt concentrations. This unexpected result may help in developing new pillarization strategies to treat effluents with high salt content.Fil: Aguiar, J. E.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Bezerra, B. T. C.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Siqueira, A. C. A.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Barrera Diaz, Deicy Amparo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Sapag, Manuel Karim. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Física Aplicada; ArgentinaFil: Azevedo, D. C. S.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Lucena, S. M. P.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; BrasilFil: Silva Jr., I. J.. Universidade Federal do Ceará. Centro de Tecnologia. Departamento de Engenharia Química. Grupo de Pesquisa em Separações por Adsorção; Brasi

    On the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects on the Harmonic Oscillator

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    In this work, we obtain bound states for a nonrelativistic spin-half neutral particle under the influence of a Coulomb-like potential induced by the Lorentz symmetry breaking effects. We present a new possible scenario of studying the Lorentz symmetry breaking effects on a nonrelativistic quantum system defined by a fixed space-like vector field parallel to the radial direction interacting with a uniform magnetic field along the z-axis. Furthermore, we also discuss the influence of a Coulomb-like potential induced by Lorentz symmetry violation effects on the two-dimensional harmonic oscillator.Comment: 14 pages, no figure, this work has been accepted for publication in The European Physical Journal Plu

    Cinética ruminal de espécies forrageiras nativas da caatinga

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    This study aimed at evaluating the kinetics of in situ ruminal degradation of the dry matter (DM), crude protein (CP) and neutral detergent fiber (NDF) of five local forage species from the semi-arid region of Paraíba (Brazil): “Orelha de Onça” (Macroptilium Martii Benth), “Amor de Vaqueiro” (Desmodium canum), “Feijão Bravo” (Capparis Flexuosa), “Maniçoba” (Manihot Epruinosa) and “Imburana de Cambão” (Camniphora leptophloes). Four two-year-old male sheep, castrated, belonging to the breed Santa Inês, with an average weight of 40 kg, previously rumen-fistulated, were distributed in an entirely randomized statistical design, with subdivided portion. The animals were housed in individual stalls and fed ad libitum with diets containing hays of the studied forages and a mineral supplementation. The foods were ground, put into nylon bags and incubated during 0, 6, 12, 24, 48 and 96 hours. Chemical-bromatological analyses of the forages were carried out to determine  in situ ruminal degradation. The solubility of DM was larger for “Feijão Bravo” hay. For the potentially degradable fraction of DM, "Maniçoba" hay presented the highest average value. Compared to the other forages, "Maniçoba" and “Feijão Bravo” hays showed the lowest percentage of the undegradable fraction (P <0,01), but the highest PD and ED (2-5%/h) of DM  (P <0,01). “Feijão Bravo” hay presented the highest rates of PD and ED (2-5%/h) of CP. Among the  forages examined, "Maniçoba" and “Feijão Bravo” hays presented the best potential for feeding. The degradability in the DM, CP and NDF indicated the best potential of use for “Feijão Bravo” and "Maniçoba", since the nutritional quality and efficiency of utilization in the rumen was higher for these forages.Este trabalho tem como objetivo avaliar a cinética da degradação ruminal in situ da matéria seca (MS), proteína bruta (PB) e fibra em detergente neutro (FDN) de cinco espécies forrageiras nativas: orelha de onça (Macroptilium Martii Benth),  amor de vaqueiro (Desmodium canum), feijão bravo (Capparis Flexuosa), maniçoba (Manihot Epruinosa) e imburana de cambão (Camniphora  leptophloes) do semi-árido paraibano. Quatro ovinos machos castrados, de dois anos de idade, da  raça Santa Inês, com peso médio de 40 kg previamente canulados no rúmen, foram distribuídos em um delineamento experimental inteiramente casualizado, com parcela subdividida. Os animais foram alojados em baias individuais e alimentados à vontade com dietas contendo os fenos das forrageiras estudadas e suplementação mineral. Os alimentos foram moídos, colocados em sacos de náilon e incubados nos tempos 0, 6, 12, 24, 48 e 96 horas. Foram realizadas análises químico-bromatológicas (MS, PB e FDN) das forrageiras para determinação da degradação ruminal  in situ. A solubilidade da MS foi maior (P>0,01) para o feno de feijão bravo. Quanto à fração potencialmente degradável da MS, o feno de maniçoba apresentou o maior valor médio. Os fenos de maniçoba e de feijão bravo apresentaram um menor percentual da fração não degradável entre as forrageiras avaliadas (P<0,01). O feno de maniçoba e feijão bravo apresentaram DP e DE (2-5%/h) da MS superior (P<0,01) às demais forrageiras. O feijão bravo apresentou as maiores taxas de DP e DE (2-5%/h) da PB. Os fenos das forrageiras, maniçoba e feijão-bravo, apresentaram o melhor potencial para arraçoamento dentre as forragens estudadas. A degradabilidade da MS, PB e FDN indicaram para os fenos de maniçoba e feijão bravo melhor potencial de utilização, visto que a qualidade nutritiva e a eficiência de aproveitamento no rúmen foram superiores para estas forragens

    Behavioral responses to injury and death in wild Barbary macaques (Macaca sylvanus)

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    The wounding or death of a conspecific has been shown to elicit varied behavioral responses throughout thanatology. Recently, a number of reports have presented contentious evidence of epimeletic behavior towards the dying and dead among non-human animals, a behavioral trait previously considered uniquely human. Here, we report on the behavioral responses of Barbary macaques, a social, non-human primate, to the deaths of four group members (one high-ranking adult female, one high-ranking adult male, one juvenile male, and one female infant), all caused by road traffic accidents. Responses appeared to vary based on the nature of the death (protracted or instant) and the age class of the deceased. Responses included several behaviors with potential adaptive explanations or consequences. These included exploration, caretaking (guarding, carrying, and grooming), and proximity to wounded individuals or corpses, and immediate as well as longer-lasting distress behaviors from other group members following death, all of which have been reported in other non-human primate species. These observations add to a growing body of comparative evolutionary analysis of primate thanatology and help to highlight the multifaceted impacts of human-induced fatalities on an endangered and socially complex primate. © 2016, Japan Monkey Centre and Springer Japan

    Lack of Guanylate Cyclase C results in increased mortality in mice following liver injury

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    <p>Abstract</p> <p>Background</p> <p>Guanylate Cyclase C (GC-C) expression in the intestine plays a role in the regulation of fluid and ion transport, as well as epithelial cell apoptosis and proliferation. In the adult rat liver, GC-C expression is increased in response to injury. We hypothesized that GC-C is required for repair/recovery from liver injury.</p> <p>Methods</p> <p>We subjected wild type (WT) and GC-C deficient mice to acute liver injury with a single injection of the hepatotoxin carbon tetrachloride. Changes in the level of expression of GC-C and its ligands uroguanylin and guanylin were quantified by real-time PCR. Liver morphology, and hepatocyte necrosis, apoptosis and proliferation, were examined at 1-3 days post-injury in mice on a mixed genetic background. Survival was followed for 14 days after carbon tetrachloride injection in wild type and GC-C deficient mice on both a mixed genetic background and on an inbred C57BL6/J background.</p> <p>Results</p> <p>GC-C deficient mice on the mixed genetic background nearly all died (median survival of 5 days) following carbon tetrachloride injection while WT littermates experienced only 35% mortality. Elevated levels of TUNEL-positive hepatocyte death on post-injury day 1, increased apoptosis on day 2, and increased areas of centrilobular necrosis on days 2 and 3, were evident in livers from GC-C null mice compared to WT. Collectively these data suggest increased hepatocyte death in the GC-C null mice in the early time period after injury. This corresponds temporally with increased expression of GC-C and its ligands guanylin and uroguanylin in post-injury WT mouse liver. The hepatocyte proliferative response to injury was the same in both genotypes. In contrast, there was no difference in survival between GC-C null and WT mice on the inbred C57BL/6 J background in response to acute liver injury.</p> <p>Conclusions</p> <p>Signalling via GC-C promotes hepatocyte survival <it>in vivo </it>and is required for effective recovery from acute toxic injury to the liver in a strain-specific manner.</p

    Indication for the disappearance of reactor electron antineutrinos in the Double Chooz experiment

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    The Double Chooz Experiment presents an indication of reactor electron antineutrino disappearance consistent with neutrino oscillations. A ratio of 0.944 ±\pm 0.016 (stat) ±\pm 0.040 (syst) observed to predicted events was obtained in 101 days of running at the Chooz Nuclear Power Plant in France, with two 4.25 GWth_{th} reactors. The results were obtained from a single 10 m3^3 fiducial volume detector located 1050 m from the two reactor cores. The reactor antineutrino flux prediction used the Bugey4 measurement as an anchor point. The deficit can be interpreted as an indication of a non-zero value of the still unmeasured neutrino mixing parameter \sang. Analyzing both the rate of the prompt positrons and their energy spectrum we find \sang = 0.086 ±\pm 0.041 (stat) ±\pm 0.030 (syst), or, at 90% CL, 0.015 << \sang  <\ < 0.16.Comment: 7 pages, 4 figures, (new version after PRL referee's comments
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