271 research outputs found

    Solving loop equations by Hitchin systems via holography in large-N QCD_4

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    For (planar) closed self-avoiding loops we construct a "holographic" map from the loop equations of large-N QCD_4 to an effective action defined over infinite rank Hitchin bundles. The effective action is constructed densely embedding Hitchin systems into the functional integral of a partially quenched or twisted Eguchi-Kawai model, by means of the resolution of identity into the gauge orbits of the microcanonical ensemble and by changing variables from the moduli fields of Hitchin systems to the moduli of the corresponding holomorphic de Rham local systems. The key point is that the contour integral that occurs in the loop equations for the de Rham local systems can be reduced to the computation of a residue in a certain regularization. The outcome is that, for self-avoiding loops, the original loop equations are implied by the critical equation of an effective action computed in terms of the localisation determinant and of the Jacobian of the change of variables to the de Rham local systems. We check, at lowest order in powers of the moduli fields, that the localisation determinant reproduces exactly the first coefficient of the beta function.Comment: 65 pages, late

    Anti-diabetic effects of Campomanesia xanthocarpa (Berg) leaf decoction

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    The objective of this research was to identify the effects of 3-week treatment of normal and streptozotocin-induced diabetic rats using a leaf decoction of Campomanesia xanthocarpa Berg. (20 g/L) on physiological, biochemical and histological parameters. Streptozotocin (STZ, 70 mg/kg in citrate buffer, pH 4.5) was administered IP to induce experimental diabetes one week prior to the treatment. STZ caused typical diabetic symptoms: polydypsia, polyuria, polyphagia, hyperglycemia, hypertriglyceridemia and histopathological modifications in the pancreas, liver and kidney. The treatment of diabetic rats using the decoction decreased blood glucose levels, inhibited hepatic glycogen loss, and prevented potential histopathological alterations in the pancreas and kidneys. No differences were found between the control rats treated with the decoction and the control rats maintained on water only. In conclusion, these results suggest that C. xanthocarpa leaf decoction (20g/L) might be useful for diabetes mellitus management, but further pharmacological and toxicological studies are needed.O objetivo deste trabalho foi identificar os efeitos do tratamento com o decocto das folhas de Campomanesia xanthocarpa Berg. (20 g/L), durante 3 semanas, sobre parâmetros fisiológicos, bioquímicos e histológicos de ratos normais e diabéticos induzidos por estreptozotocina. O diabete melito foi induzido uma semana antes de iniciar o tratamento experimental, pela administração IP de estreptozotocina (STZ, 70 mg/kg em tampão citrato, pH 4.5). Os ratos tratados com STZ apresentaram sintomas típicos de diabete: polifagia, polidipsia, hiperglicemia, hipertrigliceridemia e alterações histopatológicas no pâncreas, fígado e rim. O tratamento dos ratos diabéticos com o decocto diminuiu os níveis de glicose sanguínea, inibiu a degradação do glicogênio hepático e preveniu possíveis alterações histopatológicas no pâncreas e no rim. Nos ratos controles tratados com o decocto não foram verificadas diferenças significativas em relação aos controles tratados com água. Em conclusão, os resultados sugerem que o tratamento com o decocto das folhas de C. xanthocarpa leaf decoction (20 g/L) possa ser útil para o manejo do diabete melito, porém estudos farmacológicos e toxicológicos ainda são necessários

    Noun and verb knowledge in monolingual preschool children across 17 languages: Data from cross-linguistic lexical tasks (LITMUS-CLT)

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    This article investigates the cross-linguistic comparability of the newly developed lexical assessment tool Cross-linguistic Lexical Tasks (LITMUS-CLT). LITMUS-CLT is a part the Language Impairment Testing in Multilingual Settings (LITMUS) battery (Armon-Lotem, de Jong & Meir, 2015). Here we analyse results on receptive and expressive word knowledge tasks for nouns and verbs across 17 languages from eight different language families: Baltic (Lithuanian), Bantu (isiXhosa), Finnic (Finnish), Germanic (Afrikaans, British English, South African English, German, Luxembourgish, Norwegian, Swedish), Romance (Catalan, Italian), Semitic (Hebrew), Slavic (Polish, Serbian, Slovak) and Turkic (Turkish). The participants were 639 monolingual children aged 3;0-6;11 living in 15 different countries. Differences in vocabulary size were small between 16 of the languages; but isiXhosa-speaking children knew significantly fewer words than speakers of the other languages. There was a robust effect of word class: accuracy was higher for nouns than verbs. Furthermore, comprehension was more advanced than production. Results are discussed in the context of cross-linguistic comparisons of lexical development in monolingual and bilingual populations

    Pretense and Imagination

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    Issues of pretense and imagination are of central interest to philosophers, psychologists, and researchers in allied fields. In this entry, we provide a roadmap of some of the central themes around which discussion has been focused. We begin with an overview of pretense, imagination, and the relationship between them. We then shift our attention to the four specific topics where the disciplines' research programs have intersected or where additional interactions could prove mutually beneficial: the psychological underpinnings of performing pretense and of recognizing pretense, the cognitive capacities involved in imaginative engagement with fictions, and the real-world impact of make-believe. In the final section, we discuss more briefly a number of other mental activities that arguably involve imagining, including counterfactual reasoning, delusions, and dreaming

    Environmentally Realistic Exposure to the Herbicide Atrazine Alters Some Sexually Selected Traits in Male Guppies

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    Male mating signals, including ornaments and courtship displays, and other sexually selected traits, like male-male aggression, are largely controlled by sex hormones. Environmental pollutants, notably endocrine disrupting compounds, can interfere with the proper functioning of hormones, thereby impacting the expression of hormonally regulated traits. Atrazine, one of the most widely used herbicides, can alter sex hormone levels in exposed animals. I tested the effects of environmentally relevant atrazine exposures on mating signals and behaviors in male guppies, a sexually dimorphic freshwater fish. Prolonged atrazine exposure reduced the expression of two honest signals: the area of orange spots (ornaments) and the number of courtship displays performed. Atrazine exposure also reduced aggression towards competing males in the context of mate competition. In the wild, exposure levels vary among individuals because of differential distribution of the pollutants across habitats; hence, differently impacted males often compete for the same mates. Disrupted mating signals can reduce reproductive success as females avoid mating with perceptibly suboptimal males. Less aggressive males are at a competitive disadvantage and lose access to females. This study highlights the effects of atrazine on ecologically relevant mating signals and behaviors in exposed wildlife. Altered reproductive traits have important implications for population dynamics, evolutionary patterns, and conservation of wildlife species

    Ascitic complement system in ovarian cancer

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    Ovarian cancer spreads intraperitoneally and forms fluid, whereby the diagnosis and therapy often become delayed. As the complement (C) system may provide a cytotoxic effector arm for both immunological surveillance and mAb-therapy, we have characterised the C system in the intraperitoneal ascitic fluid (AF) from ovarian cancer patients. Most of the AF samples showed alternative and classical pathway haemolytic activity. The levels of C3 and C4 were similar to or in the lower normal range when compared to values in normal sera, respectively. However, elevated levels of C3a and soluble C5b-9 suggested C activation in vivo. Malignant cells isolated from the AF samples had surface deposits of C1q and C3 activation products, but not of C5b-9 (the membrane attack complex; MAC). Activation could have become initiated by anti-tumour cell antibodies that were detected in the AFs and/or by changes on tumour cell surfaces. The lack of MAC was probably due to the expression of C membrane regulators CD46, CD55 and CD59 on the tumour cells. Soluble forms of C1 inhibitor, CD59 and CD46, and the alternative pathway inhibitors factor H and FHL-1 were present in the AF at concentrations higher than in serum samples. Despite the presence of soluble C inhibitors it was possible to use AF as a C source in antibody-initiated killing of ovarian carcinoma cells. These results demonstrate that although the ovarian ascitic C system fails as an effective immunological surveillance mechanism, it could be utilised as an effector mechanism in therapy with intraperitoneally administrated mAbs, especially if the intrinsic C regulators are neutralised
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