Una explicación del comportamiento errático del intervalo de Wald en el modelo binomial

Recoge los contenidos presentados a: ASEPELT España. Reunión anual (21. 2007. Valladolid).Es conocido que el intervalo de Wald para estimar la proporción de éxito en una distribución binomial presenta un comportamiento muy errático con respecto a su probabilidad de cubrimiento al hacer variar los parámetros n y p. Habitualmente se ha considerado que este comportamiento es “esencialmente impredecible”. Sin embargo, el análisis de la causa de estos descensos permite obtener una fórmula que proporciona, fijado p, todos los valores de n en los que se produce un brusco descenso de la probabilidad de cubrimiento. Dicho análisis también permite comprender por qué el intervalo de Wilson presenta un comportamiento menos errático que el de Wald.The erratic behaviour of the coverage probability of the Wald interval of a binomial proportion has previously been remarke on the literture. In addition, “unlucky" values of n again arise in the same “unpredictable” way. In section 4, we present an explication on the “unlucky" of n and, also, we propos a method to calculate, fixed p, the values of n where significant change in coverage probability occurs. From the analysis of the Wald interval, we show that the performance the Wilson interval is less erratic

Potencial de conservación de la biodiversidad de bosques y árboles en fincas del paisaje ganadero Catacamas, Honduras

El estudio evaluó el potencial de conservación de biodiversidad arbórea de diferentes usos de la tierra en el paisaje ganadero Catacamas, Honduras. Se planteó la hipótesis de que los diferentes usos contribuyen en la misma medida a la conservación de la diversidad de árboles a escala de parcela y paisaje. Se muestrearon árboles con un dap mínimo de medición de 10 cm en 448 parcelas (área total de 84,2 ha) ubicadas en diferentes usos forestales y agrícolas característicos del paisaje Catacamas: bosques secundarios continuos (BS), fragmentos de bosque secundario (BSF), plantaciones de café rústico (PLANT), agricultura (AGRI), pasturas (PAST), cercas vivas (CV) y bosques ribereños (BR). Con los datos se caracterizó la estructura, composición y diversidad arbórea en el paisaje y se comparó entre los usos de la tierra

Can robotic-based top-down rehabilitation therapies improve motor control in children with cerebral palsy? A perspective on the CPWalker project

[EN] Cerebral Palsy (CP) is one of the most severe disabilities in childhood, and it demands important costs in health, education, and social services. CP is caused by damage to or abnormalities inside the developing brain that disrupt the brain's ability to control movement and maintain posture. Furthermore, CP is often associated with sensory deficits, cognition impairments, communication and motor disabilities, behavior issues, seizure disorder, pain, and secondary musculoskeletal problems. According to the literature, motor modules are peripheral measurements related to automatic motor control. There is a lack of evidence of change in motor modules in children with CP when different treatment approaches have been evaluated. Thus, new strategies are needed to improve motor control in this population. Robotic-based therapies are emerging as an effective intervention for gait rehabilitation in motor disorders such as stroke, spinal cord injury, and CP. There is vast clinical evidence that neural plasticity is the central core of motor recovery and development, and on-going studies suggest that robot-mediated intensive therapy could be beneficial for improved functional recovery. However, current robotic strategies are focused on the peripheral neural system (PNS) facilitating the performance of repetitive movements (a bottom-up approach). Since CP affects primarily brain structures, both the PNS and the central nervous system (CNS) should to be integrated in a physical and cognitive rehabilitation therapy (a top-down approach). This paper discusses perspectives of the top-down approach based on a novel robot-assisted rehabilitative system. Accordingly, the CPWalker robotic platform was developed to support novel therapies for CP rehabilitation. This robotic platform (Smart Walker + exoskeleton) is controlled by a multimodal interface enabling the interaction of CP infants with robot-based therapies. The aim of these therapies is to improve the physical skills of infants with CP using a top-down approach, in which motor related brain activity is used to drive robotic physical rehabilitation therapies. Our hypothesis is that the CPWalker concept will promote motor learning and this improvement will lead to significant improvements in automatic motor control.Lerma Lara, S.; Martínez Caballero, I.; Bayón, C.; Del Castillo, M.; Serrano, I.; Raya, R.; Belda Lois, JM.... (2016). Can robotic-based top-down rehabilitation therapies improve motor control in children with cerebral palsy? A perspective on the CPWalker project. Biomedical Research and Clinical Practice. 22-26. doi:10.15761/BRCP.1000106S222

Extinction filters mediate the global effects of habitat fragmentation on animals

Habitat loss is the primary driver of biodiversity decline worldwide, but the effects of fragmentation (the spatial arrangement of remaining habitat) are debated. We tested the hypothesis that forest fragmentation sensitivity—affected by avoidance of habitat edges—should be driven by historical exposure to, and therefore species’ evolutionary responses to disturbance. Using a database containing 73 datasets collected worldwide (encompassing 4489 animal species), we found that the proportion of fragmentation-sensitive species was nearly three times as high in regions with low rates of historical disturbance compared with regions with high rates of disturbance (i.e., fires, glaciation, hurricanes, and deforestation). These disturbances coincide with a latitudinal gradient in which sensitivity increases sixfold at low versus high latitudes. We conclude that conservation efforts to limit edges created by fragmentation will be most important in the world’s tropical forests