2,611 research outputs found

    STATUS OF THE THREE‐WATTLED BELLBIRD (PROCNIAS TRICARUNCULATUS) IN THE NICOYA MOUNTAINS, COSTA RICA

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    Abstract ∙ Wildlife conservation often relies on accurate data of species distributions, yet scientific knowledge is often limited in scope. Local knowledge and habitat mapping can provide additional information particularly useful in assessing the absence or presence of a species or population. In May 2015, we combined point counts, local interviews, citizen science databases, and habitat mapping to assess the presence of breeding Three‐wattled Bellbirds (Procnias tricarunculatus), a species listed as Vulnerable by the IUCN, in the Nicoya Mountains of Costa Rica, where a disjunct population had previously been reported. Our point counts, local interviews, and citizen science databases provided strong evidence that bellbirds no longer breed in the Nicoya Mountains, and our habitat mapping demonstrated that a minimum of 23% of the bellbird habitat is now pasture. We conclude that a putative historic resident population of this species is now most likely non‐existent in the Nicoya Mountains.Resumen ∙ Estatus del Pájaro Campana (Procnias tricarunculatus) en las montañas de Nicoya, Costa Rica La conservación de la vida silvestre se basa comúnmente en el conocimiento exacto de la distribución de las especies, sin embargo, este conocimiento es limitado para muchas especies. El conocimiento local y mapeo del hábitat pueden proveer información adicional, particularmente útil en la evaluación de la presencia o ausencia de especies o poblaciones. En mayo de 2015, combinamos puntos de conteo, entrevistas locales, bases de datos de ciencia ciudadana, y mapeo de hábitat para determinar la presencia de poblaciones reproductivas de Pájaro Campana (Procnias tricarunculatus), especie enlistada como vulnerable por la IUCN, en las montañas de Nicoya, Costa Rica, donde una población ha sido reportada previamente.  Nuestros puntos de conteo, entrevistas a locales, y bases de datos de ciencia ciudadana indican que el Pájaro Campana no se reproduce en las montañas de Nicoya; nuestro mapeo de hábitat demuestra que un 23% del hábitat del Pájaro Campana ha sido transformado en pastizales. Concluimos que una supuesta población residente histórica de esta especie es ahora muy probablemente inexistente en las montañas de Nicoya.

    Differential gene expression in the cortical sulcus compared to the gyral crest within the early stages of chronic traumatic encephalopathy

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    Chronic traumatic encephalopathy (CTE) is a progressive neurodegenerative tauopathy found in individuals with a history of repetitive head impacts (RHI). Previous work has demonstrated that neuroinflammation is involved in CTE pathogenesis, however, the specific inflammatory mechanisms are still unclear. Here, using RNA-sequencing and gene set enrichment analysis (GSEA), we investigated the genetic changes found in tissue taken from the region CTE pathology is first found, the cortical sulcus, and compared it to neighboring gryal crest tissue to identify what pathways were directly related to initial hyperphosphorylated tau (p-tau) deposition. 21 cases were chosen for analysis: 6 cases had no exposure to RHI or presence of neurodegenerative disease (Control), 5 cases had exposure to RHI but no presence of neurodegenerative disease (RHI), and 10 cases had exposure to RHI and low stage CTE (CTE). Two sets of genes were identified: genes that changed in both the sulcus and crest and genes that changed specifically in the sulcus relative to the crest. When examining genes that changed in both the sulcus and crest, GSEA demonstrated an increase in immune related processes and a decrease in neuronal processes in RHI and CTE groups. Sulcal specific alterations were observed to be driven by three mechanisms: anatomy, RHI, or p-tau. First, we observed consistent sulcal specific alterations in immune, extracellular matrix, vascular, neuronal, and endocytosis/exocytosis categories across all groups, suggesting the sulcus has a unique molecular signature compared to the neighboring crest independent of pathology. Second, individuals with a history of RHI demonstrated impairment in metabolic and mitochondrial related processes. Finally, in individuals with CTE, we observed impairment of immune and phagocytic related processes. Overall, this work provides the first observation of biological processes specifically altered in the sulcus that could be directly implicated in CTE pathogenesis and provide novel targets for biomarkers and therapies

    Multi-Attribute Tradespace Exploration for Survivability

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    Multi-Attribute Tradespace Exploration for Survivability is a system design and analysis methodology that incorporates survivability considerations into the tradespace exploration process (i.e., a solution-generating and decision-making framework that applies decision theory to model-based design). During the concept generation phase of tradespace exploration, the methodology applies seventeen empirically validated survivability design principles spanning susceptibility reduction, vulnerability reduction, and resilience enhancement. During subsequent concept evaluation, the methodology adds value-based survivability metrics to traditional architectural evaluation criteria of mission utility and lifecycle cost. Applied to a satellite radar mission, the methodology allowed operational survivability to be statistically evaluated across representative distributions of naturally occurring disturbances in the space environment and for survivability to be incorporated as a decision factor earlier in the design process. Constellations in the illustrative example are shown to be the most survivable, mitigating disturbances architecturally, rather than through additive features.Massachusetts Institute of Technology (Systems Engineering Advancement Research Initiative (SEAri))Massachusetts Institute of Technology. Program on Emerging Technologie
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