86 research outputs found

    PRIMERA CONTRIBUCIÓN AL CONOCIMIENTO DE LOS BRACONZDAE (HYM., APOCRZTA, TEREBRANTZA) PARASITOIDES DE AGROMYZZDAE (DZPT., CYCLORRAPHA) EN LA PROVINCIA DE SALAMANCA (ESPAÑA)

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    Four species of Braconidae (Alysiinae) have been found in a suivey conducted in Salamanca dunng the year 1988. Two of them are new records for Spain. Two new host-parasitoide relationships have been settled.En los muestreos llevados a cabo durante el año 1988 en la provincia de Salamanca, se han hallado cuatro especies de Branconidae (Alysiinae), dos de las cuales constituyen nuevas citas para España. Se establecen dos nuevas combinaciones entre insectos hospedadores y parasitoides

    Ab Initio Screening Approach for the Discovery of Lignin Polymer Breaking Pathways

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    The directed depolymerization of lignin biopolymers is of utmost relevance for the valorization or commercialization of biomass fuels. We present a computational and theoretical screening approach to identify potential cleavage pathways and resulting fragments that are formed during depolymerization of lignin oligomers containing two to six monomers. We have developed a chemical discovery technique to identify the chemically relevant putative fragments in eight known polymeric linkage types of lignin. Obtaining these structures is a crucial precursor to the development of any further kinetic modeling. We have developed this approach by adapting steered molecular dynamics calculations under constant force and varying the points of applied force in the molecule to diversify the screening approach. Key observations include relationships between abundance and breaking frequency, the relative diversity of potential pathways for a given linkage, and the observation that readily cleaved bonds can destabilize adjacent bonds, causing subsequent automatic cleavage.Massachusetts Institute of Technology (Research Support Corporation, Reed Grant)United States. Dept. of Energy. Computational Science Graduate Fellowship Program (DOE-CSGF)Burroughs Wellcome Fund (Career Award at the Scientific Interface

    Mnesic imbalance: a cognitive theory about autism spectrum disorders

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    Autism is characterized by impairments in social interaction, communicative capacity and behavioral flexibility. Some cognitive theories can be useful for finding a relationship between these irregularities and the biological mechanisms that may give rise to this disorder. Among such theories are mentalizing deficit, weak central coherence and executive dysfunction, but none of them has been able to explain all three diagnostic symptoms of autism. These cognitive disorders may be related among themselves by faulty learning, since several research studies have shown that the brains of autistic individuals have abnormalities in the cerebellum, which plays a role in procedural learning. In keeping with this view, one may postulate the possibility that declarative memory replaces faulty procedural memory in some of its functions, which implies making conscious efforts in order to perform actions that are normally automatic. This may disturb cognitive development, resulting in autism symptoms. Furthermore, this mnesic imbalance is probably involved in all autism spectrum disorders. In the present work, this theory is expounded, including preliminary supporting evidence
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