186 research outputs found

    Ergodic properties of quasi-Markovian generalized Langevin equations with configuration dependent noise and non-conservative force

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    We discuss the ergodic properties of quasi-Markovian stochastic differential equations, providing general conditions that ensure existence and uniqueness of a smooth invariant distribution and exponential convergence of the evolution operator in suitably weighted LL^{\infty} spaces, which implies the validity of central limit theorem for the respective solution processes. The main new result is an ergodicity condition for the generalized Langevin equation with configuration-dependent noise and (non-)conservative force

    High-resolution magnetic resonance imaging reveals nuclei of the human amygdala: manual segmentation to automatic atlas

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    Available online 4 May 2017The amygdala is composed of multiple nuclei with unique functions and connections in the limbic system and to the rest of the brain. However, standard in vivo neuroimaging tools to automatically delineate the amygdala into its multiple nuclei are still rare. By scanning postmortem specimens at high resolution (100–150 µm) at 7 T field strength (n = 10), we were able to visualize and label nine amygdala nuclei (anterior amygdaloid, cortico-amygdaloid transition area; basal, lateral, accessory basal, central, cortical medial, paralaminar nuclei). We created an atlas from these labels using a recently developed atlas building algorithm based on Bayesian inference. This atlas, which will be released as part of FreeSurfer, can be used to automatically segment nine amygdala nuclei from a standard resolution structural MR image. We applied this atlas to two publicly available datasets (ADNI and ABIDE) with standard resolution T1 data, used individual volumetric data of the amygdala nuclei as the measure and found that our atlas i) discriminates between Alzheimer's disease participants and age-matched control participants with 84% accuracy (AUC=0.915), and ii) discriminates between individuals with autism and age-, sex- and IQ-matched neurotypically developed control participants with 59.5% accuracy (AUC=0.59). For both datasets, the new ex vivo atlas significantly outperformed (all p < .05) estimations of the whole amygdala derived from the segmentation in FreeSurfer 5.1 (ADNI: 75%, ABIDE: 54% accuracy), as well as classification based on whole amygdala volume (using the sum of all amygdala nuclei volumes; ADNI: 81%, ABIDE: 55% accuracy). This new atlas and the segmentation tools that utilize it will provide neuroimaging researchers with the ability to explore the function and connectivity of the human amygdala nuclei with unprecedented detail in healthy adults as well as those with neurodevelopmental and neurodegenerative disorders.This work was supported by the PHS grant DA023427 and NICHD/ NIH grant F32HD079169 (Z.M.S); Feodor Lynen Postdoctoral Fellowship of the Alexander von Humboldt Foundation (D.K.); R21(MH106796), R21 (AG046657) and K01AG28521 (J.C.A.), the National Cancer Institute (1K25CA181632-01) as well as the Genentech Foundation (M.R.); the European Union's Horizon 2020 Marie Sklodowska-Curie grant agreement No 654911 (project ”THALAMODEL”) and ERC Starting Grant agreement No 677697 (project “BUNGEE-TOOLS”); and the Spanish Ministry of Economy and Competitiveness (MINECO) reference TEC2014-51882-P (J.E.I.); and the NVIDIA hardware award (M.R. and J.E.I.). Further support for this research was provided in part by the National Institute for Biomedical Imaging and Bioengineering (P41EB015896, R01EB006758, R21EB018907, R01EB019956, R01- EB013565), the National Institute on Aging (5R01AG008122, R01AG016495), the National Institute of Diabetes and Digestive and Kidney Diseases (1-R21-DK-108277-01), the National Institute for Neurological Disorders and Stroke (R01NS0525851, R21NS072652, R01NS070963, R01NS083534, 5U01NS086625), the Massachusetts ADRC (P50AG005134) and was made possible by the resources provided by Shared Instrumentation Grants 1S10RR023401, 1S10RR019307, and 1S10RR023043. Additional support was provided by the NIH Blueprint for Neuroscience Research (5U01-MH093765), part of the multi-institutional Human Connectome Project. In addition, BF has a financial interest in CorticoMetrics, a company whose medical pursuits focus on brain imaging and measurement technologies. BF's interests were reviewed and are managed by Massachusetts General Hospital and Partners HealthCare in accordance with their conflict of interest policies. The collection and sharing of the ADNI MRI data used in the evaluation was funded by the Alzheimer's Disease Neuroimaging Initiative (ADNI) (National Institutes of Health Grant U01 AG024904) and DOD ADNI (Department of Defense award number W81XWH-12-2- 0012). ADNI is funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, and through generous contributions from the following: Alzheimer's Association; Alzheimer's Drug Discovery Foundation; BioClinica, Inc.; Biogen Idec Inc.; Bristol-Myers Squibb Company; Eisai Inc.; Elan Pharmaceuticals, Inc.; Eli Lilly and Company; F. Hoffmann-La Roche Ltd and its affiliated company Genentech, Inc.; GE Healthcare; Innogenetics, N.V.; IXICO Ltd.; Janssen Alzheimer Immunotherapy Research & Development, LLC.; Johnson & Johnson Pharmaceutical Research & Development LLC.; Medpace, Inc.; Merck & Co., Inc.; Meso Scale Diagnostics, LLC.; NeuroRx Research; Novartis Pharmaceuticals Corporation; Pfizer Inc.; Piramal Imaging; Servier; Synarc Inc.; and Takeda Pharmaceutical Company. The Canadian Institutes of Health Research is providing funds to support ADNI clinical sites in Canada. Private sector contributions are facilitated by the Foundation for the National Institutes of Health (www. fnih.org). The grantee organization is the Northern California Institute for Research and Education, and the study is coordinated by the Alzheimer's Disease Cooperative Study at the University of California, San Diego. ADNI data are disseminated by the Laboratory for Neuro Imaging at the University of Southern California

    Self-reported sex differences in high-functioning adults with autism: a meta-analysis

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    Background: Sex differences in autistic symptomatology are believed to contribute to the mis- and missed diagnosis of many girls and women with an autism spectrum condition (ASC). Whilst recent years have seen the emergence of clinical and empirical reports delineating the profile of young autistic girls, recognition of sex differences in symptomatology in adulthood is far more limited. Methods: We chose here to focus on symptomatology as reported using a screening instrument, the Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R). In a meta-analysis, we pooled and analysed RAADS-R data from a number of experimental groups. Analysis of variance (ANOVA) searched for the presence of main effects of Sex and Diagnosis and for interactions between these factors in our sample of autistic and non-autistic adults. Results: In social relatedness and circumscribed interests, main effects of Diagnosis revealed that as expected, autistic adults reported significantly greater lifetime prevalence of symptoms in these domains; an effect of Sex, in circumscribed interests, also suggested that males generally reported more prevalent symptoms than females. An interaction of Sex and Diagnosis in language symptomatology revealed that a normative sex difference in language difficulties was attenuated in autism. An interaction of Sex and Diagnosis in the sensorimotor domain revealed the opposite picture: a lack of sex differences between typically-developing men and women and a greater prevalence of sensorimotor symptoms in autistic women than autistic men. Conclusions: We discuss the literature on childhood sex differences in relation to those which emerged in our adult sample. Where childhood sex differences fail to persist in adulthood, several interpretations exist, and we discuss, for example, an inherent sampling bias that may mean that only autistic women most similar to the male presentation are diagnosed. The finding that sensorimotor symptomatology is more highly reported by autistic women is a finding requiring objective confirmation, given its potential importance in diagnosis

    Neurobiology of social behavior abnormalities in autism and Williams syndrome

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    Social behavior is a basic behavior mediated by multiple brain regions and neural circuits, and is crucial for the survival and development of animals and humans. Two neuropsychiatric disorders that have prominent social behavior abnormalities are autism spectrum disorders (ASD), which is characterized mainly by hyposociability, and Williams syndrome (WS), whose subjects exhibit hypersociability. Here we review the unique properties of social behavior in ASD and WS, and discuss the major theories in social behavior in the context of these disorders. We conclude with a discussion of the research questions needing further exploration to enhance our understanding of social behavior abnormalities

    Abilities to explicitly and implicitly infer intentions from actions in adults with autism spectrum disorder

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    Previous research suggests that Autism Spectrum Disorder (ASD) might be associated with impairments on implicit but not explicit mentalizing tasks. However, such comparisons are made difficult by the heterogeneity of stimuli and the techniques used to measure mentalizing capabilities. We tested the abilities of 34 individuals (17 with ASD) to derive intentions from others’ actions during both explicit and implicit tasks and tracked their eye-movements. Adults with ASD displayed explicit but not implicit mentalizing deficits. Adults with ASD displayed typical fixation patterns during both implicit and explicit tasks. These results illustrate an explicit mentalizing deficit in adults with ASD, which cannot be attributed to differences in fixation patterns

    Insights into Candida tropicalis nosocomial infections and virulence factors

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    Candida tropicalis is considered the first or the second non-Candida albicans Candida (NCAC) species most frequently isolated from candidosis, mainly in patients admitted in intensive care units (ICUs), especially with cancer, requiring prolonged catheterization, or receiving broad-spectrum antibiotics. The proportion of candiduria and candidemia caused by C. tropicalis varies widely with geographical area and patient group. Actually, in certain countries, C. tropicalis is more prevalent, even compared with C. albicans or other NCAC species. Although prophylactic treatments with fluconazole cause a decrease in the frequency of candidosis caused by C. tropicalis, it is increasingly showing a moderate level of fluconazole resistance. The propensity of C. tropicalis for dissemination and the high mortality associated with its infections might be strongly related to the potential of virulence factors exhibited by this species, such as adhesion to different host surfaces, biofilm formation, infection and dissemination, and enzymes secretion. Therefore, the aim of this review is to outline the present knowledge on all the above-mentioned C. tropicalis virulence traits.The authors acknowledge Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), Brazil, for supporting Melyssa Negri (BEX 4642/06-6) and Fundacao para a Ciencia e Tecnologia (FCT), Portugal, for supporting Sonia Silva (SFRH/BPD/71076/2010), and European Community fund FEDER, trough Program COMPETE under the Project FCOMP-01-0124-FEDER-007025 (PTDC/AMB/68393/2006) is gratefully acknowledged

    Face scanning and spontaneous emotion preference in Cornelia de Lange syndrome and Rubinstein-Taybi syndrome

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    Background Existing literature suggests differences in face scanning in individuals with different socio-behavioural characteristics. Cornelia de Lange syndrome (CdLS) and Rubinstein-Taybi syndrome (RTS) are two genetically defined neurodevelopmental disorders with unique profiles of social behaviour. Methods Here, we examine eye gaze to the eye and mouth regions of neutrally expressive faces, as well as the spontaneous visual preference for happy and disgusted facial expressions compared to neutral faces, in individuals with CdLS versus RTS. Results Results indicate that the amount of time spent looking at the eye and mouth regions of faces was similar in 15 individuals with CdLS and 17 individuals with RTS. Both participant groups also showed a similar pattern of spontaneous visual preference for emotions. Conclusions These results provide insight into two rare, genetically defined neurodevelopmental disorders that have been reported to exhibit contrasting socio-behavioural characteristics and suggest that differences in social behaviour may not be sufficient to predict attention to the eye region of faces. These results also suggest that differences in the social behaviours of these two groups may be cognitively mediated rather than subcortically mediated

    Effects of vinasse irrigation on effluent ionic concentration in Brazilian Oxisols.

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    The irrigation with vinasse can improve soil fertility. However, this use should take into account the characteristics of each soil because the vinasse has unbalanced amounts of mineral and organic elements which might lead to leach the ions, especially nitrate and potassium. The purpose of this study was to evaluate the impacts of vinasse irrigation on effluent ionic concentrations in Brazilian Ferralsols from two areas in Central Brazil: a sugarcane field, and a natural undisturbed savannah area. Soil samples from the two sites were placed into PVC columns with 120 cm height × 25 cm diameter with sugarcane. Undiluted vinasse was applied once on the surface of the soil columns at doses equivalent to 0, 300, 600 and 1200 m3 ha-1. After 0, 60, 90 and 120 days of irrigation, samples of the effluent were collected and the concentrations of dissolved organic matter (DOM), Cl, Ca, Mg, Na, K, total Fe, NH4 +, NO3 -, SO4 2- as well as pH were determined. The ions concentration data were modeled in the chemical equilibrium model Visual Minteq v. 3.0. Results revealed vinasse?s dose, days after irrigation and land use had a relevant effect on most nutrients effluent concentration. Contrasting pH values were observed for both soils and in the savannah soil was observed a decrease in pH at high vinasse doses. This paper thus revealed leaching of the DOM was strongly time dependent. High vinasse doses may lead to increase nutrient leaching and soil dispersion regardless the land use and time after irrigation

    Calagem e manganês na cultura da soja em solos da região de Rio Verde-GO.

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    Foram desenvolvidos dois experimentos em casa de vegetação objetivando estudar os efeitos da correção de acidez e aplicação de manganês na produção de massa seca da soja (Glycine max L. Merrill) utilizando dois solos de Cerrado (Latossolo Vermelho-Amarelo e Neossolo Quartzar único) da regão de Rio Verde, Gois. Empregou-se o delineamento inteiramente casualizado, em esquema fatorial 5x5, com cinco doses de calcrio e cinco de manganês. Verificou-se que nos tratamentos sem calagem ocorreu toxidez de Mn, com menor produção de massa seca. Por derivação das superfícies de resposta, os níveis críticos -1 de mxima resposta a produção foram: a) Para o Latossolo: calagem = 6,06 t ha e Mn = -1 -1 10,02 mg kg , com ponto estacionário - PE (máximo) de 33,92 g vaso ; b) Para o -1 -1 -1 Neossolo: calagem = 2,88 t ha e Mn = 10,24 mg kg , com PE de 38,72 g vaso . A calagem é essencial para a cultura da soja em ambos os solos, sendo a aplicação de manganês desnecessária. A aplicação do dobro da calagem recomendada, em nenhum caso, induziu deficiência de Mn na soja
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