Ethanol Production, Food and Forests

This paper investigates the direct and indirect impacts of ethanol production on land use, deforestation and food production. A partial equilibrium model of a national economy with two sectors and two regions, one of which includes a residual forest, is developed. It analyses how an exogenous increase in the ethanol price affects input allocation (land and labor) between sectors (energy crop and food). Three potential effects are identified. First, the standard and well-documented effect of direct land competition between rival uses increases deforestation and decreases food production. Second, an indirect displacement of food production across regions, provoked by a shift in the price of food, increases deforestation and reduces the total output of the food sector. Finally, labor mobility between sectors and regions tends to decrease food production but also deforestation. The overall impact of ethanol production on forest conversion is ambiguous, providing a number of interesting pointers to further, empirical research. --Ethanol,Deforestation,Indirect impacts,Land use,Migration

Análise econômica para a pecuária de corte em pastagens melhoradas no Acre.

A pecuária de corte é a atividade com maior expressão econômica do setor agropecuário do Estado do Acre, representando aproximadamente 40% do valor bruto da produção. Contudo, sistemas de produção caracterizados como tradicionais, que apresentam baixos índices zootécnicos, predominam na maior parte das pequenas, médias e grandes propriedades. Consequentemente, o setor apresenta baixa produtividade e rentabilidade e tem causado impactos ambientais negativos decorrentes de desmatamentos, que implicam em perda de biodiversidade e degradação dos solos. Observa-se que a retração da atividade é ocasionada por diversos fatores, com destaque para medidas voltadas à redução nas taxas de desmatamento, o que limita a expansão das áreas de pastagens, e para a baixa produtividade das pastagens de Brachiaria brizantha cv. Marandu (capim-brizantão), as quais apresentam grandes áreas em processo de degradação devido à elevada incidência da síndrome da morte do capim-braquiarão nos últimos 10 anos. Assim, denota-se a necessidade de uma reestruturação do sistema produtivo da pecuária de corte no estado, com base em novos padrões de produção eficientes, que respeitem a natureza e atendam às exigências crescentes da sociedade em geral com a conservação dos recursos naturais. Nesse contexto, há quase três décadas, a Embrapa Acre desenvolve tecnologias com o objetivo de responder ao desafi o de viabilizar sistemas de produção sustentáveis destinados à pecuária de corte, que sejam economicamente rentáveis e de reduzido impacto ambiental.bitstream/CPAF-AC-2010/23476/1/circtec-n51.pd

Instruções técnicas para o cultivo da gravioleira.

A graviola (Annona muricata L.) e uma fruteira tropical, ... Exigências edafoclimáticas ...Instalação do pomar.bitstream/CNPAT-2010/5378/1/It-002.pd

Strategies for resection of lesions in the motor area - Preliminary results in 42 surgical patients

In recent years considerable technological advances have been made with the purpose of improving the surgical results in the treatment of eloquent lesions. The overall aim of this study is to evaluate the postoperative surgical outcome in 42 patients who underwent surgery to remove lesions around the motor cortex, in which preoperative planning by using neuroimaging exams, anatomical study, appropriate microsurgery technique and auxiliary methods such as cortical stimulation were performed. Twenty-two patients (52.3%) presented a normal motor function in the preoperative period. Of these, six developed transitory deficit. Twenty patients (47.6%) had a motor deficit preoperatively, nevertheless 90% of these improved postoperatively. Surgery in the motor area becomes safer and more effective with preoperative localization exams, anatomical knowledge and appropriate microsurgery technique. Cortical stimulation is important because it made possible to maximize the resection reducing the risk of a motor deficit. Stereotaxy method was useful in the location of subcortical lesions.64496397

Momentum relaxation from the fluid/gravity correspondence

We provide a hydrodynamical description of a holographic theory with broken translation invariance. We use the fluid/gravity correspondence to systematically obtain both the constitutive relations for the currents and the Ward identity for momentum relaxation in a derivative expansion. Beyond leading order in the strength of momentum relaxation, our results differ from a model previously proposed by Hartnoll et al. As an application of these techniques we consider charge and heat transport in the boundary theory. We derive the low frequency thermoelectric transport coefficients of the holographic theory from the linearised hydrodynamics.Comment: 19 pages + appendix, v2: references added, typos corrected, v3: version published in JHE

Critérios que influenciam o processo de tomada de decisão na produção familiar.

O presente trabalho buscou determinar a lógica do processo decisório dos produtores, identificando os critérios considerados indispensáveis para construção de seu modelo de produção. As informações foram obtidas dos produtores da Associação de Produtores Vencedores (Aspruve), localizada em Vila Extrema, Rondônia, utilizando a técnica "Matriz de Comparação" da metodologia do Diagnóstico Rural participativo (IAPAR, 1997).bitstream/CPAF-AC/3667/1/comunicado125.pd

Non-Equilibrium Field Dynamics of an Honest Holographic Superconductor

Most holographic models of superconducting systems neglect the effects of dynamical boundary gauge fields during the process of spontaneous symmetry-breaking. Usually a global symmetry gets broken. This yields a superfluid, which then is gauged "weakly" afterwards. In this work we build (and probe the dynamics of) a holographic model in which a local boundary symmetry is spontaneously broken instead. We compute two-point functions of dynamical non-Abelian gauge fields in the normal and in the broken phase, and find non-trivial gapless modes. Our AdS3 gravity dual realizes a p-wave superconductor in (1+1) dimensions. The ground state of this model also breaks (1+1)-dimensional parity spontaneously, while the Hamiltonian is parity-invariant. We discuss possible implications of our results for a wider class of holographic liquids.Comment: 32 pages, 12 figures; v3: string theory derivation of setup added (section 3.1), improved presentation, version accepted by JHEP; v2: paragraph added to discussion, figure added, references added, typos correcte

Boundary Conditions and Unitarity: the Maxwell-Chern-Simons System in AdS_3/CFT_2

We consider the holography of the Abelian Maxwell-Chern-Simons (MCS) system in Lorentzian three-dimensional asymptotically-AdS spacetimes, and discuss a broad class of boundary conditions consistent with conservation of the symplectic structure. As is well-known, the MCS theory contains a massive sector dual to a vector operator in the boundary theory, and a topological sector consisting of flat connections dual to U(1) chiral currents; the boundary conditions we examine include double-trace deformations in these two sectors, as well as a class of boundary conditions that mix the vector operators with the chiral currents. We carefully study the symplectic product of bulk modes and show that almost all such boundary conditions induce instabilities and/or ghost excitations, consistent with violations of unitarity bounds in the dual theory.Comment: 50+1 pages, 6 figures, PDFLaTeX; v2: added references, corrected typo