797 resultados para Vicinal organizations
Resumo:
Non-governmental organizations (NGOs) are now major players in the realm of environmental conservation. While many environmental NGOs started as national organizations focused around single-species protection, governmental advocacy, and preservation of wilderness, the largest now produce applied conservation science and work with national and international stakeholders to develop conservation solutions that work in tandem with local aspirations. Marine managed areas (MMAs) are increasingly being used as a tool to manage anthropogenic stressors on marine resources and protect marine biodiversity. However, the science of MMA is far from complete. Conservation International (CI) is concluding a 5 year, $12.5 million dollar Marine Management Area Science (MMAS) initiative. There are 45 scientific projects recently completed, with four main “nodes” of research and conservation work: Panama, Fiji, Brazil, and Belize. Research projects have included MMA ecological monitoring, socioeconomic monitoring, cultural roles monitoring, economic valuation studies, and others. MMAS has the goals of conducting marine management area research, building local capacity, and using the results of the research to promote marine conservation policy outcomes at project sites. How science is translated into policy action is a major area of interest for science and technology scholars (Cash and Clark 2001; Haas 2004; Jasanoff et al. 2002). For science to move policy there must be work across “boundaries” (Jasanoff 1987). Boundaries are defined as the “socially constructed and negotiated borders between science and policy, between disciplines, across nations, and across multiple levels” (Cash et al. 2001). Working across the science-policy boundary requires boundary organizations (Guston 1999) with accountability to both sides of the boundary, among other attributes. (Guston 1999; Clark et al. 2002). This paper provides a unique case study illustrating how there are clear advantages to collaborative science. Through the MMAS initiative, CI built accountability into both sides of the science-policy boundary primarily through having scientific projects fed through strong in-country partners and being folded into the work of ongoing conservation processes. This collaborative, boundary-spanning approach led to many advantages, including cost sharing, increased local responsiveness and input, better local capacity building, and laying a foundation for future conservation outcomes. As such, MMAS can provide strong lessons for other organizations planning to get involved in multi-site conservation science. (PDF contains 3 pages)
Resumo:
With complete sets of chromosome-specific painting probes derived from flow-sorted chromosomes of human and grey squirrel (Sciurus carolinensis), the whole genome homologies between human and representatives of tree squirrels (Sciurus carolinensis, Callosciurus erythraeus), flying squirrels (Petaurista albiventer) and chipmunks (Tamias sibiricus) have been defined by cross-species chromosome painting. The results show that, unlike the highly rearranged karyotypes of mouse and rat, the karyotypes of squirrels are highly conserved. Two methods have been used to reconstruct the genome phylogeny of squirrels with the laboratory rabbit (Oryctolagus cuniculus) as the out-group: ( 1) phylogenetic analysis by parsimony using chromosomal characters identified by comparative cytogenetic approaches; ( 2) mapping the genome rearrangements onto recently published sequence-based molecular trees. Our chromosome painting results, in combination with molecular data, show that flying squirrels are phylogenetically close to New World tree squirrels. Chromosome painting and G-banding comparisons place chipmunks ( Tamias sibiricus), with a derived karyotype, outside the clade comprising tree and flying squirrels. The superorder Glires (order Rodentia + order Lagomorpha) is firmly supported by two conserved syntenic associations between human chromosomes 1 and 10p homologues, and between 9 and 11 homologues.
Resumo:
Cross- species chromosome painting has made a great contribution to our understanding of the evolution of karyotypes and genome organizations of mammals. Several recent papers of comparative painting between tree and flying squirrels have shed some light
Resumo:
Field angle dependent critical current, magneto-optical microscopy and high resolution electron microscopy studies have been performed on YBa2Cu3O7-delta thin films grown on miscut substrates. High resolution electron microscopy images show that the films studied exhibited clean epitaxial growth with a low density of antiphase boundaries and stacking faults. Any antiphase boundaries (APBs) formed near the film substrate interface rapidly healed rather than extending through the thickness of the film. Unlike vicinal films grown on annealed substrates, which contain a high density of antiphase boundaries, magneto-optical imaging showed no filamentary flux penetration in the films studied. The flux penetration is, however, asymmetric. This is associated with intrinsic pinning of flux strings by the tilted a-b planes and the dependence of the pinning force on the angle between the local field and the a-b planes. Field angle dependent critical current measurements exhibited the striking vortex channeling effect previously reported in vicinal films. By combining the results of three complementary characterization techniques it is shown that extended APB free films exhibit markedly different critical current behavior compared to APB rich films. This is attributed to the role of APB sites as strong pinning centers for Josephson string vortices between the a-b planes. (C) 2003 American Institute of Physics.
Resumo:
We report on electrical transport measurements at high current densities on optimally doped YBa 2Cu 3O 7-δ thin films grown on vicinal SrTiO 3 substrates. Data were collected by using a pulsed-current technique in a four-probe arrangement, allowing to extend the current-voltage characteristics to high supercritical current densities (up to 24 MA cm -2) and high electric fields (more than 20 V/cm), in the superconducting state at temperatures between 30 and 80 K. The electric measurements were performed on tracks perpendicular to the vicinal step direction, such that the current crossed between ab planes, under magnetic field rotated in the plane defined by the crystallographic c axis and the current density. At magnetic field orientation parallel to the cuprate layers, evidence for the sliding motion along the ab planes (vortex channeling) was found. The signature of vortex channeling appeared to get enhanced with increasing electric field, due to the peculiar depinning features in the kinked vortex range. They give rise to a current-voltage characteristics steeper than in the more off-plane rectilinear vortex orientations, in the electric field range below approximately 1 V/cm. Roughly above this value, the high vortex channeling velocities (up to 8.6 km/s) could be ascribed to the flux flow, although the signature of ohmic transport appeared to be altered by unavoidable macroscopic self-heating and hot-electron-like effects. © 2012 Elsevier B.V. All rights reserved.