Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 13 de 13
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Glob Chang Biol ; 26(1): 274-286, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31642554

RESUMO

Energy from biomass plays a large and growing role in the global energy system. Energy from biomass can make significant contributions to reducing carbon emissions, especially from difficult-to-decarbonize sectors like aviation, heavy transport, and manufacturing. But land-intensive bioenergy often entails substantial carbon emissions from land-use change as well as production, harvesting, and transportation. In addition, land-intensive bioenergy scales only with the utilization of vast amounts of land, a resource that is fundamentally limited in supply. Because of the land constraint, the intrinsically low yields of energy per unit of land area, and rapid technological progress in competing technologies, land intensive bioenergy makes the most sense as a transitional element of the global energy mix, playing an important role over the next few decades and then fading, probably after mid-century. Managing an effective trajectory for land-intensive bioenergy will require an unusual mix of policies and incentives that encourage appropriate utilization in the short term but minimize lock-in in the longer term.


Assuntos
Biocombustíveis , Carbono , Biomassa
2.
Healthc Financ Manage ; 67(6): 111-7, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23795387

RESUMO

Hospital leaders can take four strategic steps to ensure their IT systems are prepared to meet the requirements of healthcare reform: Examine the extent to which current IT system capacity is sufficient to meet future demands. Create a solid foundation for expanding IT capabilities or implementing a new IT system. Share ownership and accountability for IT development and implementation with end users. Reconsider the value of third-party solutions.


Assuntos
Reforma dos Serviços de Saúde , Sistemas de Informação Hospitalar/organização & administração , Inovação Organizacional , Estados Unidos
3.
Ecol Lett ; 15(11): 1249-1256, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22913646

RESUMO

Efficient conservation planning requires knowledge about conservation targets, threats to those targets, costs of conservation and the marginal return to additional conservation efforts. Systematic conservation planning typically only takes a small piece of this complex puzzle into account. Here, we use a return-on-investment (ROI) approach to prioritise lands for conservation at the county level in the conterminous USA. Our approach accounts for species richness, county area, the proportion of species' ranges already protected, the threat of land conversion and land costs. Areas selected by a complementarity-based greedy heuristic using our full ROI approach provided greater averted species losses per dollar spent compared with areas selected by heuristics accounting for richness alone or richness and cost, and avoided acquiring lands not threatened with conversion. In contrast to traditional prioritisation approaches, our results highlight conservation bargains, opportunities to avert the threat of development and places where conservation efforts are currently lacking.


Assuntos
Conservação dos Recursos Naturais/economia , Modelos Teóricos , Biodiversidade , Análise Custo-Benefício , Estados Unidos
5.
Proc Natl Acad Sci U S A ; 106(5): 1305-12, 2009 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-19179280

RESUMO

The Millennium Ecosystem Assessment (MA) introduced a new framework for analyzing social-ecological systems that has had wide influence in the policy and scientific communities. Studies after the MA are taking up new challenges in the basic science needed to assess, project, and manage flows of ecosystem services and effects on human well-being. Yet, our ability to draw general conclusions remains limited by focus on discipline-bound sectors of the full social-ecological system. At the same time, some polices and practices intended to improve ecosystem services and human well-being are based on untested assumptions and sparse information. The people who are affected and those who provide resources are increasingly asking for evidence that interventions improve ecosystem services and human well-being. New research is needed that considers the full ensemble of processes and feedbacks, for a range of biophysical and social systems, to better understand and manage the dynamics of the relationship between humans and the ecosystems on which they rely. Such research will expand the capacity to address fundamental questions about complex social-ecological systems while evaluating assumptions of policies and practices intended to advance human well-being through improved ecosystem services.


Assuntos
Ecossistema , Meio Ambiente , Conservação dos Recursos Naturais , Humanos , Modelos Teóricos , Probabilidade , Especificidade da Espécie
11.
Trends Ecol Evol ; 19(5): 221-4, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-16701257

RESUMO

Hundreds of scientists from over 70 nations are now engaged in an intensive effort to assess what we know about the status of the world's ecosystems. Here, we describe the fundamental nature of this assessment, what it hopes to accomplish and how it will go about its work. The results of the Millennium Ecosystem Assessment will serve as a baseline for future assessments, as well as a blueprint for action for sustaining the ecosystem services upon which we all depend for our well being.

12.
Evolution ; 44(7): 1780-1786, 1990 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28567813

RESUMO

We examined the relative contributions of egg size and parental quality to hatching success, fledging success, and chick growth in the Magellanic penguin (Spheniscus magellanicus) be exchanging clutches between nests to reduce the covariation between egg and parental factors. Among control nests, fledging success increased slightly with egg size. However, the effect of egg size independently of parental quality was limited to an influence on chick mass and size for the first 10 days post-hatching. In contrast, attributes of the parents influenced nesting success and chick size at fledging, independently of the egg size actually raised. We suggest that the common occurrence of a positive phenotypic correlation between egg size and fledging success is due to two factors: (1) adults laying large eggs tend to be of higher quality; and (2) to the extent that egg size does influence early survival independently of parental quality, the effect on survival is due to a maternal effect on egg composition rather than an inherent effect of egg size.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...