Fatores limitantes à expansão dos sistemas produtivos de palma na Amazônia.

O mercado de óleos vegetais encontra-se em plena ascensão no mundo. O cultivo da palma-de-óleo (palmácea do gênero Elaeis), cujos maiores produtores mundiais são Malásia e Indonésia, tem se destacado nesse mercado pelas vantagens decorrentes do seu aspecto produtivo. A liderança desses países assentou-se na atuação conjunta entre setor público e privado, garantindo a ampliação sucessiva dos plantios e o incremento da agroindústria. No Brasil, o desenvolvimento dessa cultura poderia substituir as importações de óleo de palma, bem como promover a recuperação de áreas desmatadas na Amazônia. Contudo, a despeito das condições naturais favoráveis ao cultivo no País, a produção de palma não se desenvolveu. Este trabalho foi estruturado a partir do marco conceitual sobre o enfoque sistêmico no agronegócio e o conceito de cadeias produtivas associado às variáveis de desenvolvimento propostas nos modelos teóricos de Porter e Alves, sob uma perspectiva comparativa acerca da evolução do agronegócio de palma na Indonésia, na Malásia, na Colômbia e no Brasil. O objetivo foi identificar os principais fatores limitantes à expansão dos sistemas produtivos de palma na Amazônia. Ressaltam-se entre essas limitações, a falta de desenvolvimento de políticas públicas e de estratégias competitivas de longo prazo. Com efeito, parcos investimentos nas áreas de pesquisa e infraestrutura, bem como inadequação dos financiamentos e falta de apoio ao pequeno produtor, têm comprometido a expansão dessa atividade produtiva

Black string corrections in variable tension braneworld scenarios

Braneworld models with variable tension are investigated, and the corrections on the black string horizon along the extra dimension are provided. Such corrections are encrypted in additional terms involving the covariant derivatives of the variable tension on the brane, providing profound consequences concerning the black string horizon variation along the extra dimension, near the brane. The black string horizon behavior is shown to be drastically modified by the terms corrected by the brane variable tension. In particular, a model motivated by the phenomenological interesting case regarding Eotvos branes is investigated. It forthwith provides further physical features regarding variable tension braneworld scenarios, heretofore concealed in all previous analysis in the literature. All precedent analysis considered uniquely the expansion of the metric up to the second order along the extra dimension, what is able to evince solely the brane variable tension absolute value. Notwithstanding, the expansion terms aftermath, further accomplished in this paper from the third order on, elicits the successive covariant derivatives of the brane variable tension, and their respective coupling with the extrinsic curvature, the Weyl tensor, and the Riemann and Ricci tensors, as well as the scalar curvature. Such additional terms are shown to provide sudden modifications in the black string horizon in a variable tension braneworld scenarioComment: 12 pages, 5 figures, accepted in PR

Modular termination verification for non-blocking concurrency

© Springer-Verlag Berlin Heidelberg 2016.We present Total-TaDA, a program logic for verifying the total correctness of concurrent programs: that such programs both terminate and produce the correct result. With Total-TaDA, we can specify constraints on a thread’s concurrent environment that are necessary to guarantee termination. This allows us to verify total correctness for nonblocking algorithms, e.g. a counter and a stack. Our specifications can express lock- and wait-freedom. More generally, they can express that one operation cannot impede the progress of another, a new non-blocking property we call non-impedance. Moreover, our approach is modular. We can verify the operations of a module independently, and build up modules on top of each other

Custo de produção da banana em Buritis, Rondônia, 2007.

Este trabalho busca determinar o custo de produção de banana em um sistema tecnificado preconizado pela pesquisa e extensão rural para o estado de Rondônia. Para o sistema estão previstos preparo de área, calagem, adubação de plantio e produção. As mudas devem ser de procedência idônea e os frutos são comercializados despencados, em caixas. É um sistema mais intensivo em capital e tecnologia que a maioria dos sistemas implantados atualmente no estado.bitstream/CPAF-RO-2009-09/12191/1/cot322_bananaemburitis.pd

Dynamics and Production of Forage in Winter Pasture under Continuous Grazing with Energetic Supplementation

This experiment was carried out at Federal University of Santa Maria, from July 09 to November 12, 1999 to evaluate the dynamics and production of forage of oat (Avena strigosa Schreb) and italian ryegrass (Lolium multiflorum Lam) mixture. The grazing system used was continuous with variable stocking rate to maintain 1500kg/ha of herbage mass in all treatments. The heifers were subjected to different levels of energetic supplementation. They are 0, 0.7 and 1.4% of LW/day. The pasture of oat and italian ryegrass presented an accumulation rate of 45.7, 55.1 and 50.0 kg of DM/ha /day and a total dry matter (DM) production of 7067, 7222 and 8137 kg/ha for 0, 0.7 and 1.4% of LW/day levels, respectively. The average percentage of leaf component was 8.26, 11.48 and 11.72 for oat and 23.12, 22.35 and 20.93 for Italian ryegrass at 0, 0.7 and 1.4% of LW/day levels, respectively. The supplementation neither affected the accumulation rate nor the total DM production of the pasture (P\u3e 0.05). The senescent material was lower (P\u3c 0.05) with no supplementation

Effect of Energetic Supplementation on Forage Losses in an Oat and Italian Ryegrass Pasture under Continuous Grazing

The experiment was conducted at UFSM-RS to quantify herbage losses in oat and Italian ryegrass mixture under continuous grazing by beef heifers. A continuous grazing method with variable stocking rate was utilized to maintain the same herbage mass, 1500 kg DM/ha, in all treatments. The treatments consisted of levels of energetic supplement (0, 0.7 and 1.4% of LW/day). The pasture was evaluated every 28 days, when forage not suitable for grazing was collected in points previously marked in experimental area. The daily losses of herbage mass were of 22.32, 18.98 and 21.16 kg of DM/ha/day, equivalent to 2.61, 1.91 and 1.41% of LW for levels of 0, 0.7 and 1.4% of LW/day, respectively. The results showed greater stocking rates in supplemented treatments, being 21.2% and 57.4% higher in 0.7 and 1.4% LW/day, respectively, than unsupplemented one

Relativistic O(q4)O(q^4) two-pion exchange nucleon-nucleon potential: configuration space

We have recently performed a relativistic $O(q^4)$ chiral expansion of the two-pion exchange $NN$ potential, and here we explore its configuration space content. Interactions are determined by three families of diagrams, two of which involve just $g_A$ and $f_{\pi}$, whereas the third one depends on empirical coefficients fixed by subthreshold $\pi N$ data. In this sense, the calculation has no adjusted parameters and gives rise to predictions, which are tested against phenomenological potentials. The dynamical structure of the eight leading non-relativistic components of the interaction is investigated and, in most cases, found to be clearly dominated by a well defined class of diagrams. In particular, the central isovector and spin-orbit, spin-spin, and tensor isoscalar terms are almost completely fixed by just $g_A$ and $f_{\pi}$. The convergence of the chiral series in powers of the ratio (pion mass/nucleon mass) is studied as a function of the internucleon distance and, for $r>$ 1 fm, found to be adequate for most components of the potential. An important exception is the dominant central isoscalar term, where the convergence is evident only for $r>$ 2.5 fm. Finally, we compare the spatial behavior of the functions that enter the relativistic and heavy baryon formulations of the interaction and find that, in the region of physical interest, they differ by about 5%.Comment: 27 pages, 33 figure