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| Registros recuperados: 26.534 | |
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| Rosen, Stacey L.; Shapouri, Shahla. |
| African Governments and international donors are focused on improving the region’s ability to grow food to mitigate projected long-term deterioration in food security. An ERS study shows that improving grain yields is the key to reducing food insecurity in Sub-Saharan Africa. Investment and technology adoption in Sub-Saharan Africa will be a challenge. |
| Tipo: Article |
Palavras-chave: Food Security and Poverty. |
| Ano: 2010 |
URL: http://purl.umn.edu/121893 |
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| Marion Filho, Pascoal Jose; Fagundes, Jones de Oliveira; Schumacher, Gabriela. |
| This article evaluates the evolution of productivity, specialization and concentration of milk production in microregions of Rio Grande do Sul in the period 1990 to 2009. Productivity is measured by the ratio between milk production and the number of cows milked, the specialization is calculated from the location quotient (QL) and concentration is determined by the location Gini (GL), according to the geographical division of microregions of IBGE. The survey results showed that increases productivity, specialization and concentration in milk production, with emphasis on microregions of Três Passos, with QL equal to 2,33 in 2008, and Passo Fundo, with productivity of 4.197 liters/cow in 2009. The location Gini also showed a significant growth in the period... |
| Tipo: Article |
Palavras-chave: Milk; Productivity; Location Quotient; Location Gini; Agribusiness. |
| Ano: 2011 |
URL: http://purl.umn.edu/121297 |
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| Lima, Flavio Jorge; Fortes Neto, Paulo; Batista, Getulio Teixeira. |
| A bibliografia estudada para discutir a sustentabilidade da produção mineral aponta para duas correntes que debatem o assunto, caracterizadas de acordo com o ponto central das teses: a dos recursos fixos e custos oportunidades. A primeira encara os recursos explorados pela mineração como não renováveis e passíveis de exaustão. A segunda indica que novas tecnologias suprirão as demandas futuras à medida que os recursos poderão ser extraídos de fontes com menor concentração de minérios. Ambas pressupõem que o Estado poderia interferir incisivamente na questão da internalização dos custos da produção e da recuperação dos impactos ambientais. Legalmente, o Estado instituiu o principio “poluidor-pagador”, que parece não atender efetivamente a demanda degradante... |
| Tipo: Article |
Palavras-chave: Sustentabilidade; Epistemologia e mineração. |
| Ano: 2011 |
URL: http://hdl.handle.net/2315/175 |
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| Bertolino, Maria Lúcia. |
| This work has as objective to argue the environmental question concerning the conservation of the forests and biodiversity. One major issue in this question is that the Brazilian forest sector contributes with an important parcel for the Brazilian economy, generates products for direct consumption or for exportation, generates taxes and jobs for the population and, still, bring positive and negative consequences in the conservation and preservation of both renewable and not renewable natural resources. The forest economy has been, historically, responsible for one of the five largest positive commercial balances of the country and still it supplies 85% of all the products of forest origin found in the national market, therefore, alleviating the pressure on... |
| Tipo: Article |
Palavras-chave: Preservation; Biodiversity; Forests. |
| Ano: 2007 |
URL: http://hdl.handle.net/2315/106 |
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| Vanlaar, Ward. |
| It is well known that looping over observations can be slow and should be avoided. The objective of this article is to discuss two alternative solutions to looping over observations that can be used to overcome a particular data-management problem of merging datasets in which unique key identifiers changed over time. The first alternative, mapch, which is introduced in this article, uses a combination of appending, indexing, and merging to solve the problem, while the second alternative uses repeated merging. Both solutions are much quicker than looping over observations. However, depending on the nature of the problem, one solution may work better than the other. It is argued that the use of such dataset-type manipulations may be suitable to overcome... |
| Tipo: Article |
Palavras-chave: Mapch; Appending; Data management; Indexing; Looping; Merging; Research Methods/ Statistical Methods. |
| Ano: 2008 |
URL: http://purl.umn.edu/122620 |
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| Alcântara, E.H.. |
| O presente trabalho tem como objetivo analisar os processos de mistura no sistema estuarino do Rio Periá (Maranhão State, Brazil) e zonear o sistema através da classificação de Kjerfve (1987). Foi utilizado o modelo matemático de Dyer e Taylor (1973), para analisar os processos de mistura. Para obtenção dos objetivos, a batimetria do sistema estuarino foi levantada, e com a mesma foram delimitados os limites atingidos pelas marés alta e baixa. Foram analisados, num padrão unidimensional: as salinidades e as concentrações e/ou frações de água doce nas marés alta e baixa; as taxas e os tempos de descarga; e os volumes de água doce retidos no estuário nas estofas de enchente e vazante. Foram obtidos os seguintes resultados: o volume de água no sistema possuí... |
| Tipo: Article |
Palavras-chave: Salinidade; Rio Periá (MG); Estuários; Análise unidimensional; Processos de mistura; Tempo de descarga. |
| Ano: 2007 |
URL: http://hdl.handle.net/2315/118 |
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| McRae, Timothy B.; Cox, Rodney J.; Watson, Geoff K.. |
| In this paper the results of a situation analysis of the Australian venison industry are presented from a study commissioned as part of the development process of an endorsed strategic plan for the Australian farmed venison industry. An extensive literature review, combined with in depth interviews with industry participants, revealed that the Australian venison industry is currently in an extended slump, characterised by a lack of viability within the industry. This lack of viability is due to many factors including, a decline in the number of large scale producers, reduced slaughter and production levels, historically low farm gate returns and very low demand for venison in the domestic market. A significant decline in export demand for venison has also... |
| Tipo: Article |
Palavras-chave: Venison; Situation analysis; Farm Management. |
| Ano: 2006 |
URL: http://purl.umn.edu/122523 |
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| Bia, Michela; Mattei, Alessandra. |
| In this article, we briefly review the role of the propensity score in estimating dose–response functions as described in Hirano and Imbens (2004, Applied Bayesian Modeling and Causal Inference from Incomplete-Data Perspectives, 73–84). Then we present a set of Stata programs that estimate the propensity score in a setting with a continuous treatment, test the balancing property of the generalized propensity score, and estimate the dose–response function. We illustrate these programs by using a dataset collected by Imbens, Rubin, and Sacerdote (2001, American Economic Review 91: 778–794). |
| Tipo: Article |
Palavras-chave: Gpscore; Doseresponse; Doseresponse_model; Bias removal; Dose–response function; Generalized propensity score; Weak unconfoundedness; Research Methods/ Statistical Methods. |
| Ano: 2008 |
URL: http://purl.umn.edu/122599 |
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| Kaminski, Jonathan; Kan, Iddo; Fleischer, Aliza. |
| This article proposes a proactive approach for analyzing agricultural adaptation to climate change based on a structural land-use model wherein farmers maximize profit by allocating their land between crop-technology bundles. The profitability of the bundles is a function of four technological attributes via which climate variables‟ effect is channeled: yield potential; input requirements; yields' sensitivity to input use; and farm-level management costs. Proactive adaptation measures are derived by identifying the technological attributes via which climate variables reduce overall agricultural profitability, despite adaptation by land reallocation among bundles. By applying the model to Israel, we find that long-term losses stem from yield potential... |
| Tipo: Article |
Palavras-chave: Adaptation; Agricultural land use; Climate change; Crop-technology bundles; Land Economics/Use. |
| Ano: 2011 |
URL: http://purl.umn.edu/120076 |
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| Registros recuperados: 26.534 | |
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