The spectral gap for some spin chains with discrete symmetry breaking

We prove that for any finite set of generalized valence bond solid (GVBS) states of a quantum spin chain there exists a translation invariant finite-range Hamiltonian for which this set is the set of ground states. This result implies that there are GVBS models with arbitrary broken discrete symmetries that are described as combinations of lattice translations, lattice reflections, and local unitary or anti-unitary transformations. We also show that all GVBS models that satisfy some natural conditions have a spectral gap. The existence of a spectral gap is obtained by applying a simple and quite general strategy for proving lower bounds on the spectral gap of the generator of a classical or quantum spin dynamics. This general scheme is interesting in its own right and therefore, although the basic idea is not new, we present it in a system-independent setting. The results are illustrated with an number of examples.Comment: 48 pages, Plain TeX, BN26/Oct/9

N-body simulations of gravitational dynamics

We describe the astrophysical and numerical basis of N-body simulations, both of collisional stellar systems (dense star clusters and galactic centres) and collisionless stellar dynamics (galaxies and large-scale structure). We explain and discuss the state-of-the-art algorithms used for these quite different regimes, attempt to give a fair critique, and point out possible directions of future improvement and development. We briefly touch upon the history of N-body simulations and their most important results.Comment: invited review (28 pages), to appear in European Physics Journal Plu

Empathy and emotion recognition in people with autism, first-degree relatives, and controls

Empathy is the lens through which we view others' emotion expressions, and respond to them. In this study, empathy and facial emotion recognition were investigated in adults with autism spectrum conditions (ASC; N=314), parents of a child with ASC (N=297) and IQ-matched controls (N=184). Participants completed a self-report measure of empathy (the Empathy Quotient [EQ]) and a modified version of the Karolinska Directed Emotional Faces Task (KDEF) using an online test interface. Results showed that mean scores on the EQ were significantly lower in fathers (p0.05) of children with ASC compared to controls, whilst both males and females with ASC obtained significantly lower EQ scores (p0.05). Finally, results indicated significant differences between males and females with ASC for emotion recognition performance (p0.05). These findings suggest that self-reported empathy deficits in fathers of autistic probands are part of the 'broader autism phenotype'. This study also reports new findings of sex differences amongst people with ASC in emotion recognition, as well as replicating previous work demonstrating empathy difficulties in adults with ASC. The use of empathy measures as quantitative endophenotypes for ASC is discussed

Virulence genotypes of feline urinary Escherichia coli isolates from New Zealand and Great Britain differ

Some of the strains of E. coli that cause urinary tract infection (UTI) in dogs and cats are reportedly indistinguishable from strains that cause serious extraintestinal infections in humans, despite the use of highly discriminating molecular tests including macrorestriction analysis and extended virulence factor genotyping. There is little incriminating evidence concerning feline urinary E. coli, but the potential for zoonotic transmission from pet cats to humans has nevertheless been suggested. One of several factors complicating this field of study is that human urinary E. coli isolates from different geographic regions have been shown to differ genetically. It is to be expected that feline urinary E. coli isolates will also differ according to geographic origin, but this has not been studied. Such information would assist future epidemiological investigations of this potential, unproven, zoonotic association. We retrospectively studied 36 cystocentesis-derived E. coli isolates from cats with UTI, 15 from New Zealand, and 21 from UK, by extended virulence factor (VF) genotyping using multiplex PCR to determine the presence or absence of 25 genes encoding fimbrial structures, toxins, siderophores, and protectins. We also carried out macrorestriction analysis of Xba1-digested bacterial DNA from each isolate using pulsed-field gel electrophoresis (PFGE). PFGE revealed 36 distinct band patterns, the closest DICE similarity between any two clones being 69%. According to UPGAMA cluster analysis of VF profiles, the 36 isolates segregated into 3 groups at a similarity level of approximately 60%, two of which contained exclusively UK isolates, the third being mixed. Cross-validated discriminant analysis based on the VF genotypes correctly categorized 15/15 NZ isolates and 17/21 UK isolates. Four P fimbrialencoding genes papA, papEF, papC, and papG III were present in all of the New Zealand isolates, but in a significantly smaller proportion, 43%, of UK isolates (Fisher’s exact test, p , 0.0005). Conversely, the protectins colicin (cvaC), serum survival factor (iss), and serum resistance factor (traT) were absent from all of the NZ isolates but present in 42%, 48%, and 67% of UK isolates, respectively (Fisher’s exact test, p # 0.005). This study has revealed substantial VF genotypic differences between feline urinary E. coli isolates from UK and New Zealand and calls into question the use of VF genotypes to study the zoonotic potential of feline urinary E. coli unless the source of isolates is carefully considered. In this retrospective study, clinical information concerning the NZ cats was incomplete, whereas all of the UK cats had been diagnosed with renal insufficiency or chronic renal failure. Therefore it cannot be ruled out that different disease states in the members of these two populations contributed to the genetic differences detected in the E. coli isolates derived from them

Effects of essential oils of Rosmarinus officinalis Linn. and Origanum vulgare Linn. from different origins on Sporothrix brasiliensis and Sporothrix schenckii complex

ABSTRACT Rosmarinus officinalis L. (rosemary) and Origanum vulgare L. (oregano) are known to have antimicrobial properties, but studies on sporotrichosis are scarce. This study aimed to evaluate the anti-Sporothrix spp. activity of essential oils from commercial products and oils extracted from aerial parts of these plants and analyze their chemical constituents. S. schenckii complex and S. brasiliensis (n: 25) isolated from humans, cats, dogs, and environmental soil were tested through M27-A3 guidelines of CLSI with modification for phytotherapics. The essential oils of R. officinalis L. were similar for MIC50 and MFC50 ≤2.25mg/mL for extracted oil; and 4.5mg/mL and 9mg/mL, respectively, for commercial oil. Both products showed MIC90 of 18mg/mL and MFC90 of 36mg/mL. In O. vulgare L., the extracted oil had better activity with MIC50 and MFC50 ≤2.25mg/mL, and MIC90 and MFC90 of 4.5mg/mL, whereas the commercial oil showed MIC50 and MFC50 of 9mg/mL and MIC90 18mg/mL, respectively, and MFC90 of 36mg/mL. Through gas chromatography (CG/FID), thymol and α-terpinene were majority for extracted oil of O. vulgare L., and carvacrol and γ-terpinene made up the majority of the commercial oil. Both essential oils of R. officinalis L. showed 1,8-cineole and α-pinene as major. The fungal isolates were susceptible to all tested essential oils, including in itraconazole-resistant S. brasiliensis isolates. The extracted and commercial oils of the plants presented in vitro anti-Sporothrix spp. activity, and they are promising for treatment of sporotrichosis, including in cases refractory to itraconazole. More studies should be performed about toxicity and in vivo efficacy for its safe use

Atividade antifúngica do óleo essencial de Origanum vulgare frente a Malassezia pachydermatis

Objetivou-se com este estudo avaliar a atividade antifúngica in vitro do óleo essencial de Origanum vulgare frente a isolados clínicos de Malassezia pachydermatis. As folhas secas de O. vulgare foram adquiridas de distribuidor comercial com certificado de qualidade e origem e encaminhadas para extração do óleo essencial e cromatografia. Para realização do teste in vitro, foi utilizada a técnica de microdiluição em caldo (CLSI M27A3) com modificações para fitofármacos e M. pachydermatis. O óleo essencial de orégano foi testado nas concentrações de 28 a 0,87mg/mL diluído em caldo Sabouraud com 1% de tween 80. Todos os isolados foram testados em duplicata. Na análise cromatográfica do óleo essencial, foram identificados 12 compostos, sendo timol, a-terpineno e 4-terpineol os compostos majoritários. A CIM e a CFM dos 42 isolados de M. pachydermatis variaram de <0,87 a 7mg/mL, com valores de CIM50 e CIM90 de 1,18 e 3,28mg/mL, respectivamente. Com este estudo foi possível concluir que M. pachydermatis é sensível ao óleo essencial de orégano mesmo em concentrações baixas. Dessa maneira, o óleo essencial de orégano apresenta-se como promissor na bioprospecção de novos fármacos para o tratamento das otites e dermatites na clínica de pequenos animais

Use of Triticum aestivum in open wound healing: a clinical, pathological, and tensiometric assessment in the rabbit model

While Triticum sp. has been shown to act in wound healing, stimulating collagen synthesis by fibroblasts, the use of this plant extract has yet to be assessed in vivo, in commercially viable presentations. This study used rabbits and assessed, on days seven, 14, and 21, the presence or absence of granulation tissue and epithelialization, histopathological structures, and scar quality through the breaking and tension strength. Treatments, performed for 21 days, were aqueous extract of T. aestivum at a concentration of 2mg/mL (group I) and 10mg/mL (group II) and a nonionic cream (control group). We demonstrate that the formation of granulation tissue was not significantly different between treatments. In the analysis of epithelial tissue, wounds in group II differed from other treatments by day 7. On days 14 and 21 there was no significant clinical difference between groups. In the histopathological evaluation, scar quality and rupture strength did not differ between the groups in the studied period. In the tension strength evaluation, group I differed from the others, presenting a higher tension strength overall. The studied treatments did not differ regarding healing evolution of the skin wounds, but T. aestivum extract, at 2mg/mL, presents better results in the tension strength evaluation