988 resultados para Hyperbolic conservation laws


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Life history, habits, structure, industry, conservation efforts for: Blue Crabs; Oyster; Fin fishes - shad, rock, croaker; Sport fish and fishing - marine and fresh-water; other aquatic forms - Diamondback terrapin, muskrat. Problems that confront husbandry and conservation of the commercial species, while many of the fish types found in the Chesapeake Bay are superior from the sportive viewpoint. (PDF contains 103 pages)

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We extend the classic Merton (1969, 1971) problem that investigates the joint consumption-savings and portfolio-selection problem under capital risk by assuming sophisticated but time-inconsistent agents. We introduce stochastic hyperbolic preferences as in Harris and Laibson (2013) and find closed-form solutions for Merton's optimal consumption and portfolio selection problem in continuous time. We find that the portfolio rule remains identical to the time-consistent solution with power utility and no borrowing constraints. However,the marginal propensity to consume out of wealth is unambiguously greater than the time-consistent, exponential case and,importantly, it is also more responsive to changes in risk. These results suggest that hyperbolic discounting with sophisticated agents offers promise for contributing to explaining important aspects of asset market data.

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Elasmobranchs are vital and valuable components of the marine biota. From an ecological perspective they occupy the role of top predators within marine food webs, providing a regulatory control that helps balance the ecosystem. From an evolutionary perspective, this group represents an early divergence along the vertebrate line that produced many unusual, but highly successful, adaptations in function and form. From man's perspective, elasmobranchs have been considered both an unavoidable nuisance, and an exploitable fishery resource. A few of the large shark species have earned a dubious notoriety because of sporadic attacks on humans that occur in coastal areas each year worldwide; the hysteria surrounding an encounter with a shark can be costly to the tourist industry. More importantly, elasmobranchs are often considered a detriment to commercial fishing operations; they cause significant economic damage to catches and fishing gear. On the other hand, consumer attitudes have changed concerning many previously unpopular food fishes, including elasmobranchs, and this group of fishes has been increasingly used by both recreational and commercial fishing interests. Many elasmobranchs have become a popular target of recreational fishermen for food and sport because of their abundance, size, and availability in coastal waters. Similarly, commercial fisheries for elasmobranchs have developed or expanded from an increased demand for elasmobranch food products. (PDF file contains 108 pages.)

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The 23rd Annual Symposium on Sea Turtle Biology and Conservation was held between 17 and 21 March 2003 at The Legend Hotel in Kuala Lumpur, Malaysia, hosted by the Community Conservation Network, Hawaii, and WWF-Malaysia. The meeting was attended by slightly more than 300 participants representing 73 countries, a dramatic drop in participation from previous years brought about in no small part by the looming war in the middle east region and concerns over travel safety. For 22 years the Symposium had bee an Americas-based event, even though it is the annual gathering of the "international" sea turtle society, and with the move to Malaysia, the Symposium hoped to raise the awareness among the general public of the plight of amrine turtles in Southeast Asia, and share the enormous exspertise of the world authorities on sea turtles with this so-far underrepresented region. Adopting the thems, "Living With Turtles", the Symposium had a very personal flavour, and the smaller number of participants made it possible to make and renew acquaintances, and have time for discussion between sessions. While the travel safety concern excuse was often quoted, it was a pity, particularly to the large contingent of people who attended the event for the first time from underrepresented regions, that many of the household names linked to marine turtle biology and conservation were not present to share their knowledge and promote the global concerns on the plight of turtle populations.

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The fisheries laws and regulations presently operative in Nigeria are on marine waters. These include: 1) The Sea Fisheries Decree (Act) of 1971; 2) The Sea Licencing Regulations of 1971; 3) The Sea Fisheries (Fishing) Regulations of 1972; and 4) The exclusive Economic Zone Decree of 1978. Attempts have also been made to produce the Inland waters Fisheries Regulation

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Features of homologous relationship of proteins can provide us a general picture of protein universe, assist protein design and analysis, and further our comprehension of the evolution of organisms. Here we carried Out a Study of the evolution Of protein molecules by investigating homologous relationships among residue segments. The motive was to identify detailed topological features of homologous relationships for short residue segments in the whole protein universe. Based on the data of a large number of non-redundant Proteins, the universe of non-membrane polypeptide was analyzed by considering both residue mutations and structural conservation. By connecting homologous segments with edges, we obtained a homologous relationship network of the whole universe of short residue segments, which we named the graph of polypeptide relationships (GPR). Since the network is extremely complicated for topological transitions, to obtain an in-depth understanding, only subgraphs composed of vital nodes of the GPR were analyzed. Such analysis of vital subgraphs of the GPR revealed a donut-shaped fingerprint. Utilization of this topological feature revealed the switch sites (where the beginning of exposure Of previously hidden "hot spots" of fibril-forming happens, in consequence a further opportunity for protein aggregation is Provided; 188-202) of the conformational conversion of the normal alpha-helix-rich prion protein PrPC to the beta-sheet-rich PrPSc that is thought to be responsible for a group of fatal neurodegenerative diseases, transmissible spongiform encephalopathies. Efforts in analyzing other proteins related to various conformational diseases are also introduced. (C) 2009 Elsevier Ltd. All rights reserved.

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A discussion is presented on the importance of conservation of fishery resources, considering in particular the situation in Nigeria and providing also an outline of various legislations made by government. Suggestions are given regarding the following: education on the importance of conservation; fish farming or aquaculture; restocking or rejuvenation of depleted water bodies; stock assessment; monitoring and surveillance; provision of fishing inputs; and, extension research linkage

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In order to make a sound proposal to the Kainji Lake Fisheries Management and Conservation Unit regarding the amendment of the existing Fisheries Laws and Regulations, including the raise of fishing license fees, the Fisheries Departments of 21 Nigerian States were visited in August-September 2000. In that occasion the staff was interviewed, existing documents were revised, and the results were compared with those of Kebbi and Niger State

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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)