65 research outputs found

    A holographic principle for the existence of parallel spinor fields and an inequality of Shi-Tam type

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    Suppose that Σ=M\Sigma=\partial M is the nn-dimensional boundary of a connected compact Riemannian spin manifold (M,  ,  )( M,\langle\;,\;\rangle) with non-negative scalar curvature, and that the (inward) mean curvature HH of Σ\Sigma is positive. We show that the first eigenvalue of the Dirac operator of the boundary corresponding to the conformal metric   ,  H=H2  ,  \langle\;,\;\rangle_H=H^2\langle\;,\;\rangle is at least n/2n/2 and equality holds if and only if there exists a parallel spinor field on M M. As a consequence, if Σ\Sigma admits an isometric and isospin immersion ϕ\phi with mean curvature H0H_0 as a hypersurface into another spin Riemannian manifold M0 M_0 admitting a parallel spinor field, then \begin{equation} \label{HoloIneq} \int_\Sigma H\,d\Sigma\le \int_\Sigma \frac{H^2_0}{H}\, d\Sigma \end{equation} and equality holds if and only if both immersions have the same shape operator. In this case, Σ\Sigma has to be also connected. In the special case where M0=Rn+1M_0=\R^{n+1}, equality in (\ref{HoloIneq}) implies that MM is an Euclidean domain and ϕ\phi is congruent to the embedding of Σ\Sigma in MM as its boundary. We also prove that Inequality (\ref{HoloIneq}) implies the Positive Mass Theorem (PMT). Note that, using the PMT and the additional assumption that ϕ\phi is a strictly convex embedding into the Euclidean space, Shi and Tam \cite{ST1} proved the integral inequality \begin{equation}\label{shi-tam-Ineq} \int_\Sigma H\,d\Sigma\le \int_\Sigma H_0\, d\Sigma, \end{equation} which is stronger than (\ref{HoloIneq}) .Comment: arXiv admin note: text overlap with arXiv:1502.0408

    Existence of constant mean curvature graphs in hyperbolic space

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    On an inequality of Brendle in the hyperbolic space

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    International audienceWe give a spinorial proof of a Heintze-Karcher type inequality in the hyperbolic space proved by Brendle [Br]. The proof relies on a generalized Reilly formula on spinors recently obtained in [HMR].Sur une inégalité de Brendle dans l'espace hyperbolique Résumé. On donne une nouvelle démonstration d'une inégalité de type Heintze-Karcher dans l'espace hyperbolique prouvée par Brendle [Br]. Cette preuve re-pose sur une formule de Reilly généralisée pour l'opérateur de Dirac que nous avons récemment obtenus dans [HMR]

    Satellitome analysis of Rhodnius prolixus, one of the main Chagas disease vector species

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    The triatomine Rhodnius prolixus is the main vector of Chagas disease in countries such as Colombia and Venezuela, and the first kissing bug whose genome has been sequenced and assembled. In the repetitive genome fraction (repeatome) of this species, the transposable elements represented 19% of R. prolixus genome, being mostly DNA transposon (Class II elements). However, scarce information has been published regarding another important repeated DNA fraction, the satellite DNA (satDNA), or satellitome. Here, we offer, for the first time, extended data about satellite DNA families in the R. prolixus genome using bioinformatics pipeline based on low-coverage sequencing data. The satellitome of R. prolixus represents 8% of the total genome and it is composed by 39 satDNA families, including four satDNA families that are shared with Triatoma infestans, as well as telomeric (TTAGG)n and (GATA)n repeats, also present in the T. infestans genome. Only three of them exceed 1% of the genome. Chromosomal hybridization with these satDNA probes showed dispersed signals over the euchromatin of all chromosomes, both in autosomes and sex chromosomes. Moreover, clustering analysis revealed that most abundant satDNA families configured several superclusters, indicating that R. prolixus satellitome is complex and that the four most abundant satDNA families are composed by different subfamilies. Additionally, transcription of satDNA families was analyzed in different tissues, showing that 33 out of 39 satDNA families are transcribed in four different patterns of expression across samples

    Síndrome compartimental por extravasación de líquidos en paciente pediátrico, reporte de un caso y revisión de la literatura.: Compartment syndrome due to liquid extravasation in a pediatric patient. Case report and bibliographic review

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    Extravasation Compartment Syndrome (SCE) is an infrequent pathology, with an incidence of 0,01-6,5%, whom 1,8-11% are children. Communication in children is usually difficult, with high risk of development of SCE. A case about a 9 month old male patient with an over-infected viral pneumonia and a triggered SCE is presented. He received compartmental decompression of right forearm and right hand; however he presented mild sequelae. Treatment of extravasation injury is not always sufficient enough. Mild-to-moderate complications or SCE can be presented. Recognizing clinical manifestations and risk factors and the use of auxiliary studies is fundamental for a good diagnosis and as prevention in children. Faciotomies, gold standard for treatment, are not completely safe, and have an impact on morbidity. Early protocols against extravasation, early examination by surgeon and investigation about SCE in chil-dren are recommended.El Síndrome Compartimental por Extravasación (SCE) es una patología poco frecuente, con una incidencia de 0,01-6,5%, 1.8-11% en niños. En niños pequeños la comunicación es difícil y aumenta el riego de desarrollo de SCE. Se presenta un caso de un masculino de 9 meses de edad, con Neumonía viral sobreinfectada que desencadena SCE; recibió descompresión compartimental del antebrazo y mano derecha; con desarrollo de secuelas leves. Aplicar tratamiento para lesión por extravasación no siempre es suficiente; existen complicaciones leves-moderadas o SCE. Reconocer manifestaciones clínicas y factores de riesgo es fundamental para el diagnóstico, con estudios auxiliares como precaución en niños. La faciotomía, tratamiento estándar de oro; no es inocua e impacta en la morbilidad. Se recomiendan protocolos oportunos para extravasación, valoración temprana por cirujano, investigaciones en pediatría

    Service encounters across the lifespan in individuals with autism spectrum disorders: Results from a multisite study in Latin America

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    Background Core symptoms of Autism Spectrum Disorder (ASD) continue to affect everyday life as children grow and transition into adulthood. That way, different services may be needed at various stages of their lifetimes. This study aimed to describe service encounters and hours of service per week for individuals with ASD in Latin American countries and compare the data from three age groups (preschoolers, school-aged, and adolescents). Methods: The data were obtained from an online survey adapted by Red Espectro Autista Latinoamerica (REAL) in 6 different countries in South & Central America. The total sample was composed of 2520 caregivers of children and adolescents with ASD. Results: Services encounters for Speech, Occupational and Behavioral Therapies decreased with patient age, while medication increased. Regardless of the age group, a large proportion of individuals (19-37%) were not receiving treatment, and those receiving treatment got fewer hours than best practice recommendations. For adolescents, the gaps in treatment are even greater and less consistent. Discussion Failure to offer timely identification and intervention for ASD will result in more impairment of the individual and burden for the family. Although there are several initiatives to develop more resources for this population in Latin-America, the provision of services for ASD is still undervalued. Many such individuals might not be receiving the services they need, while most children are mainly receiving therapies with low to moderate evidence at a frequency below the recommended standards

    Age of diagnosis, service access, and rights of autistic individuals in Argentina: Caregivers reports of changes and similarities across time

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    Background: Many countries have developed health initiatives to protect those with disabilities and developmental concerns in the past few years. However, the needs of autistic individuals are still short of being fulfilled. Partially due to limited research expenditure, which would allow bridging the gap between evidence and practice, the long time it takes to implement passed laws, and the limited operationalization of inclusive policies. Objective: To quantitatively examine changes in the child\u27s age at the time of caregiver\u27s first developmental concerns and age of diagnosis of their autistic child across 5 years. Also, to address challenges experienced by caregivers (e.g., reported service barriers) and the work still needing to be done in Argentina based on caregivers\u27 reports of their priorities (e.g., ensuring their child receives better services). Methods: Two independent samples of caregivers of autistic individuals were surveyed by the Red Espectro Autista Latinoamerica (REAL) in 2015 (n = 763) and the World Health Organization (WHO) in 2020 (n = 422). Similar items in both surveys were compared through descriptive inferential analysis and chi-square tests for categorical variables. Results: Compared to the 2015 sample, for the 2020 sample, more caregivers reported an earlier age of first concerns and an earlier age of a professional diagnosis. In the 2020 sample, more children diagnosed before the age of three had a doctor or a teacher noticing the first developmental concern. Also, in this sample, fewer caregivers reported service barriers (e.g., limited availability, waitlist, costs, etc.) and a need for better social support and better health services. However, rates of caregivers indicating a need for more rights for autistic individuals and greater protection of existing rights increased. There was no change in the reported rate of family members who stopped working to care for the autistic individual. For both samples, there was statistically significant differences in individual (physician, teacher, caregiver) noticing first developmental concern and the age of diagnosis, with the majority having a caregiver noticing the first concern. Conclusion: The 5 years that separate both samples show an improvement in developmental concerns being noticed, a decrease in age of diagnosis, and an improvement in several service areas such as community awareness. Also, caregivers reported fewer barriers to service accessibility, thus suggesting a positive impact stemming from changes in public policies, non-profit organizations\u27 work through awareness campaigns, and advocates\u27 strives toward greater awareness. Nonetheless, a similar proportion of family members reported ceasing working to care for autistic individuals and perceived that the fundamental rights of their autistic children needed to be protected. These results imply that despite better care pathways in Argentina, there are still gaps when attempting to meet the needs of autistic individuals and their families. The present study provides a meaningful understanding of existing gaps and help exemplify the perceived improvements when non-profit agencies and advocates promote increased rights and community awareness in addition to the established laws focusing on ASD

    Profile of Service Use and Barriers to Access to Care among Brazilian Children and Adolescents with Autism Spectrum Disorders

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    Delayed diagnosis and a lack of adequate care for people with autism spectrum disorder (ASD) are related to worse outcomes and quality of life. This study aimed to identify the profile of service use, barriers to access care, and factors related to those barriers in Brazilian families with children with ASD. A total of 927 families with children with ASD (3-17 years) from five Brazilian regions completed an online version of the Caregivers Needs Survey. Results showed that the most used services were behavioral interventions and pharmacotherapy, while the most used professionals were neurologists, nutritionists, speech therapists, psychiatrists, psychologists, and pediatricians. The main barriers included waiting lists, costs, and the absence of services or treatment. Service use varied according to age, the region of residence, type of health care system used, and the parents/caregivers\u27 education. Access to behavioral interventions was more frequent among users of the private system/health insurance and families whose caregivers had higher education. The absence of specialized services/treatments was less frequent among residents of state capitals and families whose caregivers had higher levels of education. This study highlights how families with children/adolescents with ASD in Brazil face significant barriers to access care related to sociodemographic factors
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