85 research outputs found

    Eigenvalue estimates for submanifolds of warped product spaces

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    We give lower bounds for the fundamental tone of open sets in minimal submanifolds immersed into warped product spaces of type Nn×fQqN^n \times_f Q^q, where f∈C∞(N)f \in C^\infty(N). We also study the essential spectrum of these minimal submanifolds.Comment: 17 page

    Pinworms of the red howler monkey (Alouatta seniculus) in Colombia. Gathering the pieces of the pinworm-primate puzzle

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    Pinworms of primates are believed to be highly host specific parasites, forming co-evolutionary associations with their hosts. In order to assess the strength and reach of such evolutionary links, we need to have a broad understanding of the pinworm diversity associated with primates. Here, we employed an integrative taxonomic approach to assess pinworm diversity in red howler monkeys in Colombia. Molecular and morphological evidence validate the presence of at least four different species of Trypanoxyuris occurring in red howler monkeys: T. minutus, a widely distributed species, and three new species, T. seunimiii n. sp., T. kemuimae n. sp. and T. kotudoi n. sp. The mitochondrial COI gene and the 28S ribosomal gene were used for phylogenetic assessments through Bayesian inference. The three new species were morphologically distinct and formed reciprocally monophyletic lineages. Further molecular lineage subdivision in T. minutus and T. kotudoi n. sp. without morphological correspondence, suggests the potential scenario for the existence of cryptic species. Phylogenetic relationships imply that the different species of Trypanoxyuris occurring in each howler monkey species were acquired through independent colonization events. On-going efforts to uncover pinworm diversity will allow us to test the degree of host specificity and the co-phylogenetic hypothesis, as well as to further unravel the primate-pinworm evolutionary history puzzle

    Investigacion sobre secado natural y solar de trozos de yuca con aire forzado con un ventilador

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    The natural and solar drying system of cassava chips using natural air forced through the product with the help of a fan is described. This process enables drying to occur in the least time possible without affecting chip quality; likewise, it is not expensive. The system consists of a rural drying bin, a fan, and a solar collector which is optional depending on the drying capacity of the natural air. Illustrations are provided of the system; tables included indicate the materials required and the costs of constructing the different components of the system. The costs of different attachments are also indicated as well as labor requirements. (CIAT

    Consumo de alcohol y tabaco en escolares y adolescentes de tunja, colombia, 2009

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    Objetivo Caracterizar, el consumo de tabaco y alcohol y los factores psicosociales de riesgo y de protección para el consumo en estudiantes de Secundaria/Media Académica o Técnica de Tunja durante el año 2009. Métodos Estudio de prevalencia. Se evaluaron la prevalencia y factores determinantes del consumo en una muestra de 1 515 escolares de entre 13 y 18 años de edad matriculados en los grados 8° a 11°. Resultados Media de edad 15,2 años (SD=1,42); 50,2 % mujeres; prevalencia de vida: bebidas alcohólicas 73,47%, embriaguez 51,68 %, cigarrillos 50,56 %. Principales determinantes del consumo: familia disfuncional, presión e influencia de pares y grupo, dificultades académicas, conflictos con padres o tutores. Edad media de inicio: período transicional entre los 12 y los 13 años. Se reporta casi absoluta libertad para acceder a las bebidas alcohólicas y a los cigarrillos. Conclusiones Se encuentra que la frecuencia de consumo de alcohol y tabaco es bastante alta en este grupo de edad, además que los determinantes asociados son factores susceptibles de intervenciones educativas que deben considerarse prioritarias, en particular las que tienen que ver con el ambiente familiar y el grupo de pares, dada la enorme influencia que los compañeros y miembros de colectivos deportivos o recreacionales pueden tener sobre los adolescentes de este grupo de edad

    Associations between plasma neurofilament light, in vivo brain pathology, and cognition in non-demented individuals with autosomal-dominant Alzheimer's disease

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    BACKGROUND: Neurofilament light (NfL) is a promising biomarker of early neurodegeneration in Alzheimer's disease (AD). We examined whether plasma NfL was associated with in vivo amyloid beta and tau, and cognitive performance in non-demented presenilin-1 (PSEN1) E280A mutation carriers. METHODS: Twenty-five mutation carriers and 19 non-carriers (age range: 28 to 49 years) were included in this study. Participants underwent 11C Pittsburgh compound B (PiB)-PET (positron emission tomography), flortaucipir-PET, blood sampling, and cognitive testing. RESULTS: Mutation carriers exhibited higher plasma NfL levels than non-carriers. In carriers, higher NfL levels were related to greater regional tau burden and worse cognition, but not amyloid beta load. When we adjusted for age, a proxy of disease progression, elevated plasma NfL levels were only correlated with worse memory recall. CONCLUSIONS: Findings support an association between plasma NfL, cognition, and tau pathology in non-demented individuals at genetic risk for developing AD dementia. Plasma NfL may be useful for selecting individuals at increased risk and tracking disease progression in AD

    Toward an operative diagnosis in sepsis: a latent class approach

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    <p>Abstract</p> <p>Background</p> <p>Recent data have suggested that 18 million of new sepsis cases occur each year worldwide, with a mortality rate of almost 30%. There is not consensus on the clinical definition of sepsis and, because of lack of training or simply unawareness, clinicians often miss or delay this diagnosis. This is especially worrying; since there is strong evidence supporting that early treatment is associated with greater clinical success. There are some difficulties for sepsis diagnosis such as the lack of an appropriate gold standard to identify this clinical condition. This situation has hampered the assessment of the accuracy of clinical signs and biomarkers to diagnose sepsis.</p> <p>Methods/design</p> <p>Cross-sectional study to determine the operative characteristics of three biological markers of inflammation and coagulation (D-dimer, C-reactive protein and Procalcitonin) as diagnostic tests for sepsis, in patients admitted to hospital care with a presumptive infection as main diagnosis.</p> <p>Discussion</p> <p>There are alternative techniques that have been used to assess the accuracy of tests without gold standards, and they have been widely used in clinical disciplines such as psychiatry, even though they have not been tested in sepsis diagnosis. Considering the main importance of diagnosis as early as possible, we propose a latent class analysis to evaluate the accuracy of three biomarkers to diagnose sepsis.</p

    Fluid challenges in intensive care: the FENICE study A global inception cohort study

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    Fluid challenges (FCs) are one of the most commonly used therapies in critically ill patients and represent the cornerstone of hemodynamic management in intensive care units. There are clear benefits and harms from fluid therapy. Limited data on the indication, type, amount and rate of an FC in critically ill patients exist in the literature. The primary aim was to evaluate how physicians conduct FCs in terms of type, volume, and rate of given fluid; the secondary aim was to evaluate variables used to trigger an FC and to compare the proportion of patients receiving further fluid administration based on the response to the FC.This was an observational study conducted in ICUs around the world. Each participating unit entered a maximum of 20 patients with one FC.2213 patients were enrolled and analyzed in the study. The median [interquartile range] amount of fluid given during an FC was 500 ml (500-1000). The median time was 24 min (40-60 min), and the median rate of FC was 1000 [500-1333] ml/h. The main indication for FC was hypotension in 1211 (59 %, CI 57-61 %). In 43 % (CI 41-45 %) of the cases no hemodynamic variable was used. Static markers of preload were used in 785 of 2213 cases (36 %, CI 34-37 %). Dynamic indices of preload responsiveness were used in 483 of 2213 cases (22 %, CI 20-24 %). No safety variable for the FC was used in 72 % (CI 70-74 %) of the cases. There was no statistically significant difference in the proportion of patients who received further fluids after the FC between those with a positive, with an uncertain or with a negatively judged response.The current practice and evaluation of FC in critically ill patients are highly variable. Prediction of fluid responsiveness is not used routinely, safety limits are rarely used, and information from previous failed FCs is not always taken into account

    Behavioural and Developmental Interventions for Autism Spectrum Disorder: A Clinical Systematic Review

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    Background: Much controversy exists regarding the clinical efficacy of behavioural and developmental interventions for improving the core symptoms of autism spectrum disorders (ASD). We conducted a systematic review to summarize the evidence on the effectiveness of behavioural and developmental interventions for ASD. Methods and Findings: Comprehensive searches were conducted in 22 electronic databases through May 2007. Further information was obtained through hand searching journals, searching reference lists, databases of theses and dissertations, and contacting experts in the field. Experimental and observational analytic studies were included if they were written in English and reported the efficacy of any behavioural or developmental intervention for individuals with ASD. Two independent reviewers made the final study selection, extracted data, and reached consensus on study quality. Results were summarized descriptively and, where possible, meta-analyses of the study results were conducted. One-hundred-and-one studies at predominantly high risk of bias that reported inconsistent results across various interventions were included in the review. Meta-analyses of three controlled clinical trials showed that Lovaas treatment was superior to special education on measures of adaptive behaviour, communication and interaction, comprehensive language, daily living skills, expressive language, overall intellectual functioning and socialization. High-intensity Lovaas was superior to low-intensity Lovaas on measures of intellectual functioning in two retrospective cohort studies. Pooling the results of two randomized controlle
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