RESUMO
Natural selection is an important driver of genetic and phenotypic differentiation between species. For species in which potential gene flow is high but realized gene flow is low, adaptation via natural selection may be a particularly important force maintaining species. For a recent radiation of New World desert shrubs (Encelia: Asteraceae), we use fine-scale geographic sampling and population genomics to determine patterns of gene flow across two hybrid zones formed between two independent pairs of species with parapatric distributions. After finding evidence for extremely strong selection at both hybrid zones, we use a combination of field experiments, high-resolution imaging, and physiological measurements to determine the ecological basis for selection at one of the hybrid zones. Our results identify multiple ecological mechanisms of selection (drought, salinity, herbivory, and burial) that together are sufficient to maintain species boundaries despite high rates of hybridization. Given that multiple pairs of Encelia species hybridize at ecologically divergent parapatric boundaries, such mechanisms may maintain species boundaries throughout Encelia.
Assuntos
Asteraceae/genética , Clima Desértico , Hibridização Genética , Seleção Genética , Ecossistema , Fluxo Gênico , Aptidão Genética , Herbivoria , México , Salinidade , Água , VentoRESUMO
La colonoscopia se considera como la prueba de elección para el tamizaje del cáncer colorrectal. Su eficacia dependerá de múltiples factores entre los que se incluyen una preparación adecuada, una inspección meticulosa al realizar la exploración, apego a las recomendaciones de seguimiento y una capacitación óptima del colonoscopista. Para asegurar que los endoscopistas a nivel nacional brinden una colonoscopia de calidad, surge la iniciativa de establecer indicadores de calidad locales. A continuación, la Asociación Costarricense de Gastroenterología y Endoscopia Digestiva propone los indicadores de calidad para la realización de colonoscopias seguras y efectivas.
Colonoscopy is considered as the gold standard study for colorectal cancer. The efficacy of colonoscopy depends on multiple factors, including a correct bowel preparation, careful inspection tecnique, close following of the screening guidelines and adecuate training of the colonoscopist. The initiative of establishing local quality indicatorsarise from the necessity to arise the quality of the colonospy delivered by Costarican endoscopists. On this document, the Costarican Society of Gastroenterology and Digestive Endoscopy establishes quality indicators for performing safe and effective colonoscopy.
RESUMO
Las posturas que identifican las causas de un efecto adverso (EA) han sido vistas únicamente desde una perspectiva cuantitativa, con fines de determinar la incidencia, evitabilidad y factores de riesgo, lo que resulta complicado por la subjetividad del fenómeno.
Assuntos
Humanos , Enfermagem , Preparações Farmacêuticas , Nível de Efeito Adverso não ObservadoRESUMO
Previous studies have investigated whether routine use of antiepileptic drugs is adequate to improve cognitive abilities in children who are learning disabled not otherwise specified (LD NOS) and who display interictal paroxysmal patterns in the electroencephalogram (EEG) but do not have epilepsy, and the findings of these studies have been controversial. In the current study, 112 LD children without epilepsy were assessed; however, only 18 met the strict inclusion/exclusion criteria in order to obtain a homogeneous sample. These children showed interictal paroxysmal patterns in the EEG, and a randomized, double-blind trial was carried out on them. The children were treated with either magnesium valproate (MgV; 20mg/kg/day) or a placebo for six months, and differences in WISC subtests, in a computerized reading skills battery (BTL) and EEG recordings were evaluated between groups before and after the treatment period. Performance IQ score and several items of the BTL (rhymes and ordering of words) improved in children who received MgV, whereas no changes were observed in the placebo group. No changes in the number of interictal paroxysmal patterns were observed in any group; however increased EEG currents at 10.92 and 12.87Hz (alpha band) in posterior regions and decreased currents in frequencies within the theta band (3.90, 4.29 and 5.07Hz) in frontal regions and at 4.68 and 5.46Hz in the parietal cortex were observed, suggesting an improvement in EEG maturation.