22,438 research outputs found
Minimal mechanisms for vegetation patterns in semiarid regions
The minimal ecological requirements for formation of regular vegetation
patterns in semiarid systems have been recently questioned. Against the general
belief that a combination of facilitative and competitive interactions is
necessary, recent theoretical studies suggest that, under broad conditions,
nonlocal competition among plants alone may induce patterns. In this paper, we
review results along this line, presenting a series of models that yield
spatial patterns when finite-range competition is the only driving force. A
preliminary derivation of this type of model from a more detailed one that
considers water-biomass dynamics is also presented. Keywords: Vegetation
patterns, nonlocal interactionsComment: 8 pages, 4 figure
From car to bike. Marketing and dialogue as a driver of change
The Paris Climate Agreement has sent a key message to the international community regarding the need to increase efforts to move towards a low-carbon economy and help slow climate change, while underpinning global long-term economic growth and sustainable development. COP 21 recognizes the social, economic and environmental value of voluntary mitigation actions and their co-benefits for adaptation, health and sustainable development. In this framework, the PTP Cycle project, running from 2013 to 2016 and funded by the European Commission through the Intelligent Energy Europe program, introduces a non-market approach through voluntary participation in the adoption of sustainable transport modes such as cycling, based on marketing to potential customers through Personalized Travel Plans. The medium-sized city of Burgos (Spain) and the cities of Ljubljana, Riga, Antwerp and London
(boroughs of Haringey and Greenwich) developed a new policy instrument (Personalized Travel Plans) in order to increase bike patronage. Beyond potential savings of CO2, the results show that PTP as a form of Active Mobility Consultancy is a suitable instrument to influence modal shift to public transport, walking and cycling, and to address the challenges of climate change, while fostering sustainable transportation by changing mobility behaviour. These results, matching with the state-of-the-art of studies and pilot applications in other countries, allows deriving differentiated results for medium-size and large urban areas
Una descripción geológica del carbonífero cantábrico en 1831
La "Descripción geognóstica del terreno de carbón de piedra de la provincia de Asturias" llevada a cabo por una Comisión de Facultativos formada por J. Ezquerra del Bayo, F. García, R. Amar de la Torre y F. Bauzá (Ezquerra et al., 183 l), constituye de hecho el primer estudio geológico que se efectuó en el Carbonífero del norte de España. Promovido a instancias de Fausto de Elhuya, Director General de Minas, para prospectar la importancia económica de la cuenca en vistas al empleo del carbón de piedra como combustible para la Marina de Guerra, se trata de un verdadero reconocimiento geológico, que constituye el punto de partida de la numerosísirna bibliografía que ha llegado a producir el Carbonífero de esta región. El interés de este trabajo fue ya bien reconocido por Barrois en 1882 y sus propios autores eran conscientes de que abrían con él un camino en la investigación minera regional cuando escribían "somos los primeros que hemos emprendido un trabajo de esta naturaleza en esta provincia" (Ezquerra et al., 1831, pág. 37). La "Descripción geognóstica" forma parte en realidad de una memoria más extensa titulada 'Minas de carbón de piedra de Asturias", que incluye además informes sobre las alternativas posibles del transporte del carbón a fin de darle salida por un puerto de mar. EL DESCUBRIMIENTO DEL CARBO
L1CAM binds ErbB receptors through Ig-like domains coupling cell adhesion and neuregulin signalling.
During nervous system development different cell-to-cell communication mechanisms operate in parallel guiding migrating neurons and growing axons to generate complex arrays of neural circuits. How such a system works in coordination is not well understood. Cross-regulatory interactions between different signalling pathways and redundancy between them can increase precision and fidelity of guidance systems. Immunoglobulin superfamily proteins of the NCAM and L1 families couple specific substrate recognition and cell adhesion with the activation of receptor tyrosine kinases. Thus it has been shown that L1CAM-mediated cell adhesion promotes the activation of the EGFR (erbB1) from Drosophila to humans. Here we explore the specificity of the molecular interaction between L1CAM and the erbB receptor family. We show that L1CAM binds physically erbB receptors in both heterologous systems and the mammalian developing brain. Different Ig-like domains located in the extracellular part of L1CAM can support this interaction. Interestingly, binding of L1CAM to erbB enhances its response to neuregulins. During development this may synergize with the activation of erbB receptors through L1CAM homophilic interactions, conferring diffusible neuregulins specificity for cells or axons that interact with the substrate through L1CAM
Autologous Transplantation of Adrenal Medulla Into the Caudate Nucleus: A Four Year Follow Up Study
The objective of this study was to determine whether the associated morbidity and mortality of adrenal medulla autologous transplantation into the striatum (open transcortical procedure) justifies this as a safe and effective treatment for Parkinson's Disease (PD)
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