Os pequenos produtores de leite do semi-arido nordestino: diferentes formas de insercao no mercado regional.

O trabalho apresenta as principais conclusoes de analise comparativa, considerando as condicoes de emergencia e a diversidade de algumas areas de producao de leite no Nordeste semi-arido; as diferentes formas de de insercao ao mercado dos pequenos produtores de leite. Uma reflexao sobre os fatores de desenvolvimento dessas bacias permitiu tirar algumas informacoes para a difusao das experiencias de valorizacao dos produtos da agricultura familiar no Brasil. As regioes estudadas foram: Nossa Senhora da Gloria-SE, Cariri-SE, Pintadas-BA, Taua-CE. Estudaram as condicoes de emergencia e a diversidade das areas de producao das bacias de producao leiteira no Nordeste semi-arido, tipos de pequenos produtores, estrutura e localizacao da propriedade, qualificacao do produtor, a producao e a comercializacao do queijo caseiro e as industrias de laticinios.bitstream/item/196543/1/Agricultura-familiar-pag-135-151.pd

O estudo das cadeias produtivas para o desenvolvimento da agricultura familiar.

Face ao contexto de globalizacao da economia, os orgaos publicos e privados de pesquisa e de desenvolvimento agricola estao recorrendo aos estudos das cadeias produtivas como subsidios e pontos de partida para responder melhor as demandas dos agentes economicos. Este trabalho apresenta alguns resultados de tres estudos de cadeias (uva de mesa, melao e leite), destacando o papel da agricultura familiar no negocio agricola, fornecendo dados qualitativos e quantitativos quanto a competitividade no quadro do processo e sua integracao nos mercados nacional e internacional. Alem de confirmar a importancia social e economica da agricultura familiar, esses estudos trazem elementos de reflexoes sobre a articulacao e a complementaridade dos estudos dos sistemas de producao com os estudos das cadeis produtivas

A pequena produção de leite no Semi-Árido sergipano.

Trata sobre a evolução da bacia leiteira, a evolução dos sistemas agropecuários e os sistemas de produção. A tipologia estrutural, os pequenos produtores de leite; estratégias e práticas dos pequenos produtores de leite , mudanças importantes no sistema tecnológico; tipologia funcional dos pequenos produtores de leite, práticas comuns aos produtores da região, manejo das pastagens e da palma forrageira, a silagem de milho; o manejo do rebanho e o melhoramento genético.bitstream/CPATSA/8848/1/SDC153.pd

Diversidade das formas de integração ao mercado: o caso da valorização dos laticínios pela agricultura familiar no sertão sergipano.

O leite representa, hoje, um dos principais vetores de integracao ao mercado da agricultura familiar nordestina. O diagnostico dos circuitos de comercializacao do leite e derivados produzidos na bacia leiteira centrada em Nossa Senhora da Gloria, no semi-arido sergipano, mostra que a diversidade dos sistemas de producao corresponde tambem, uma diversidade das formas de comercializacao. A valorizacao dos produtos da agricultura familiar nordestina realiza-se segundo diferentes logicas: domestica, artesanal, mercantil e industrial que podem operar num mesmo lugar de maneira paralela, complementar ou contraditoria. O enfoque dinamico da valorizacao dos laticinios no Estado de Sergipe contribui para identificar os impactos locais do contexto da globalizacao economica: emergencia de novos atores agro-industriais com uma logica multinacional, evolucao dos mercados internos e das normas de qualidade, entre outros. Mesmo assim, permanece uma grande diversidade de atores economicos, marcada pelo papel dos intermediarios que se situam na interface dessas diversas logicas

Mitochondrial Substrate-Level Phosphorylation as Energy Source for Glioblastoma: Review and Hypothesis

Glioblastoma multiforme (GBM) is the most common and malignant of the primary adult brain cancers. Ultrastructural and biochemical evidence shows that GBM cells exhibit mitochondrial abnormalities incompatible with energy production through oxidative phosphorylation (OxPhos). Under such conditions, the mitochondrial F0-F1 ATP synthase operates in reverse at the expense of ATP hydrolysis to maintain a moderate membrane potential. Moreover, expression of the dimeric M2 isoform of pyruvate kinase in GBM results in diminished ATP output, precluding a significant ATP production from glycolysis. If ATP synthesis through both glycolysis and OxPhos was impeded, then where would GBM cells obtain high-energy phosphates for growth and invasion? Literature is reviewed suggesting that the succinate-CoA ligase reaction in the tricarboxylic acid cycle can substantiate sufficient ATP through mitochondrial substrate-level phosphorylation (mSLP) to maintain GBM growth when OxPhos is impaired. Production of high-energy phosphates would be supported by glutaminolysis-a hallmark of GBM metabolism-through the sequential conversion of glutamine -> glutamate -> alpha-ketoglutarate -> succinyl CoA -> succinate. Equally important, provision of ATP through mSLP would maintain the adenine nucleotide translocase in forward mode, thus preventing the reverse-operating F0-F1 ATP synthase from depleting cytosolic ATP reserves. Because glucose and glutamine are the primary fuels driving the rapid growth of GBM and most tumors for that matter, simultaneous restriction of these two substrates or inhibition of mSLP should diminish cancer viability, growth, and invasion

The N-P-K soil nutrient balance of portuguese cropland in the 1950s: the transition from organic to chemical fertilization

Agricultural nutrient balances have been receiving increasing attention in both historical and nutrient management research. The main objectives of this study were to further develop balance methodologies and to carry out a comprehensive assessment of the functioning and nutrient cycling of 1950s agroecosystems in Portugal. Additionally, the main implications for the history of agriculture in Portugal were discussed from the standpoint of soil fertility. We used a mass balance approach that comprises virtually all nitrogen (N), phosphorus (P) and potassium (K) inputs and outputs from cropland topsoil for average conditions in the period 1951–56. We found a consistent deficit in N, both for nationwide (−2.1 kg.ha−1.yr−1) and arable crops (−1.6 kg.ha−1.yr−1) estimates, that was rectified in the turn to the 1960 decade. P and K were, in contrast, accumulating in the soil (4.2–4.6 kg.ha−1.yr−1 and 1.0–3.0 kg.ha−1.yr−1, respectively). We observed that the 1950s is the very moment of inflection from an agriculture fertilized predominantly through reused N in biomass (livestock excretions plus marine, plant and human waste sources) to one where chemical fertilizers prevailed. It is suggested that N deficiency played an important role in this transitioninfo:eu-repo/semantics/publishedVersio

A 300-year record of sedimentation in a small tilled catena in Hungary based on δ13C, δ15N, and C/N distribution

Purpose Soil erosion is one of the most serious hazards that endanger sustainable food production. Moreover, it has marked effects on soil organic carbon (SOC) with direct links to global warming. At the same time, soil organic matter (SOM) changes in composition and space could influence these processes. The aim of this study was to predict soil erosion and sedimentation volume and dynamics on a typical hilly cropland area of Hungary due to forest clearance in the early eighteenth century. Materials and methods Horizontal soil samples were taken along two parallel intensively cultivated complex convex-concave slopes from the eroded upper parts at mid-slope positions and from sedimentation in toe-slopes. Samples were measured for SOC, total nitrogen (TN) content, and SOMcompounds (δ13C, δ15N, and photometric indexes). They were compared to the horizons of an in situ non-eroded profile under continuous forest. On the depositional profile cores, soil depth prior to sedimentation was calculated by the determination of sediment thickness. Results and discussion Peaks of SOC in the sedimentation profiles indicated thicker initial profiles, while peaks in C/N ratio and δ13C distribution showed the original surface to be ~ 20 cm lower. Peaks of SOC were presumed to be the results of deposition of SOC-enriched soil from the upper slope transported by selective erosion of finer particles (silts and clays). Therefore, changes in δ13C values due to tillage and delivery would fingerprint the original surface much better under the sedimentation scenario than SOC content. Distribution of δ13C also suggests that the main sedimentation phase occurred immediately after forest clearance and before the start of intense cultivation with maize. Conclusions This highlights the role of relief in sheet erosion intensity compared to intensive cultivation. Patterns of δ13C indicate the original soil surface, even in profiles deposited as sediment centuries ago. The δ13C and C/N decrease in buried in situ profiles had the same tendency as recent forest soil, indicating constant SOM quality distribution after burial. Accordingly, microbiological activity, root uptake, and metabolism have not been effective enough to modify initial soil properties