Maize Production and Agricultural Policies in Central America and Mexico

This paper reviews trends in maize production and consumption in Central America and Mexico in the context of the political and economic changes taking place in the region since the 1970s. The authors focus on the effects of the structural adjustment programs in the 1980s and 1990s. The analysis begins by reviewing the economic context in which maize production occurs in the region and the main economic policy instruments affecting the maize economy. Next, trends in maize consumption and production are analyzed, along with the main factors influencing maize production, including trends in the public financing of maize research and extension. The authors find that several factors related to structural adjustment have defined--and are still defining--the course of agriculture, including maize production, in the countries of the region. The impact of these factors on maize production, consumption, and import trends has been different in Central America and in Mexico. In particular, the reduction or complete elimination of production incentives, the reduction of trade barriers, the liberalization of input and product prices, the deregulation of the currency exchange rate, the control of inflation, and the restructuring of agricultural research systems between the public and the private sectors have determined how basic grains are produced in the region and how they will be produced in the future. Furthermore, the visible and increasing deterioration of the natural resource base has raised great concern about the need to promote more sustainable, environmentally friendly uses of production systems and natural resources.Agricultural and Food Policy, Crop Production/Industries,

Adoption of Maize Conservation Tillage in Azuero, Panama

An aggressive research and validation program launched in 1984 in Azuero, Panama, yielded a recommendation advocating zero tillage for maize production. Ten years later, maize farmers in Azuero used three land preparation methods: conventional tillage, zero tillage, and minimum tillage (an adaptation of the zero tillage technology). This study aimed to quantify the adoption of zero and minimum tillage for maize in Azuero; identify factors influencing adoption of the different land preparation practices; and analyze the implications of the findings for future maize research and extension. Between 1985 and 1994, farmers in Region I of Azuero changed from conventional tillage to zero (33%) and minimum tillage (43%). In Regions II and III, most farmers still practiced conventional tillage in 1994, although 34% had switched to minimum tillage. Across regions, adoption of conservation tillage was motivated by potential cost savings rather than longer term considerations such as reduced soil erosion. The factors that limit adoption of conservation tillage vary by region. In Region I, adoption of conservation tillage is limited by land rental rather than ownership and by lack of conservation tillage planting equipment. In Regions II and III, lack of information about conservation tillage technology limits the probability of adoption. Future research should examine soil compaction, a key variable for understanding differences between the adoption of minimum and zero tillage. Another area that merits further research is the link between weeds and conservation tillage: several farmers reported using the technology to obtain better weed control. The long-term effects of conservation tillage should also be assessed. Extension in Regions II and III should seek to accelerate adoption of conservation tillage, particularly zero tillage. In Region I, extension should steer the change process from minimum to zero tillage.Crop Production/Industries,

Avaliação em estudantes universitários quanto ao conhecimento e prevenção de dst/aids mediante o uso do preservativo.

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina, Centro de Ciências da Saúde, Departamento de Saúde Pública, Curso de Medicina, Florianópolis, 200

Detecção sorológica de riquétsias do grupo da febre maculosa e levantamento acarológico em equinos no Distrito Federal, Brasil

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Agronomia e Veterinária, 2014.A febre maculosa brasileira (FMB) é uma zoonose causada pela bactéria Rickettsia rickettsii e transmitida a humanos por carrapatos. Procurou-se detectar a presença do principal agente etiológico da FMB circulando em equinos apreendidos no Distrito Federal, Brasil. Durante um ano foram coletadas amostras de sangue e ectoparasitos de 122 equinos. Após teste por reação de imunofluorescência indireta (RIFI), para anticorpos IgG anti R. rickettsii 21 amostras foram positivas em titulações variáveis de 1:64 a 1:512. Dos 618 carrapatos coletados, 449 pertenciam ao gênero Anocentor, 113 ao Boophilus e 36 do gênero Amblyomma. Como conclusão foi possível identificar a circulação de Rickettsia em equinos no DF, Brasil. ______________________________________________________________________________________ ABSTRACTThe Brazilian spotted fever (BSF) is a zoonosis caused by the bacteria Rickettsia rickettsii and transmitted to humans by ticks. In this study we tried to detect the BSF ethiological agent in horses apprehended by animal control in Distrito Federal, Brazil. Over one year the blood and ectoparasites were sampled on 122 horses. The samples were tested by indirect imunnofluorescence antibody assay (IFA) for R. rickettsii anti-IgG antibody, 21 samples were positive for titer ranging from 1:64 to 1:512. Among the 618 ticks collected, 449 belonged to the Anocentor genus, 113 to Boophilus and 36 were Amblyomma. The bacteria were detected in horses in Distrito Federal

Power System Modelling A techno-economic analysis of the island of Menorca, Spain

It is hard to overstate the need for humanity to address what is arguably one of the most pressing issues of our generation: climate change. Although electricity generation only accounts for about a quarter of global carbon emissions, it is one of the sectors for which a wide range of technologies are already commercially available and increasingly competitive. The decarbonization of other energy-intensive and high emitting sectors: agriculture, transportation, heating and industrial processes such as cement and steel production, although still lagging behind due to both technical and economic challenges, are beginning to show signs of progress. In some cases, electrification will be the most viable path to decarbonization, as seen in the light-duty transportation sector, where electric vehicles are already a reality. For many others, technological innovation will play a crucial role in bringing viable solutions to market. If approached pragmatically, the power sector is in a position to be the first piece of the puzzle to transition to a fundamentally sustainable way of sourcing energy. The analysis herein presented aims to identify the cost-optimum power system that can reliably supply the Spanish island of Menorca with electricity for the next ten years, from 2021 to 2030. Menorca’s power sector is computationally modelled and simulated using the open-source power system modelling tool Switch 2.0. The study is divided into different scenarios and the results of the techno-economic optimization are presented and discussed in terms of their technical feasibility, carbon footprint and costs. In addition to a standard base case scenario, the impact of factors such as fuel cost fluctuations and policy-related externalities (carbon price and renewable energy mandates) are also assessed as separate scenarios. The results of the techno-economic analysis show a clear and consistent trend across all scenarios: renewable energy technologies, namely solar PV and onshore wind power, represent the cheapest source of new bulk electricity generation in Menorca. As such, they are poised to drastically change the current fossil-based and centralized power system of the island, becoming the main sources of electricity. The base case – the most conservative scenario, in which carbon emissions are not priced, fuel costs are kept constant and no renewable energy mandate is set – solar PV and wind power account for two thirds of the total electricity supply by 2030. The penetration of renewables is even higher for the other scenarios modelled

O papel da biópsia cerebral estereotáxica no diagnóstico de lesões cerebrais neoplásicas.

Trabalho de Conclusão de Curso - Universidade Federal de Santa Catarina. Curso de Medicina. Dapartamento de Clínica Cirúrgica

Numerical simulation of a non-reactive turbulent flow inside a cyclonic industrial boiler using LES and URANS

A numerical simulation of a non-reactive turbulent flow inside a cyclonic industrial CO boiler was investigated in order to understand the swirling formation, the fluid behavior in different locations inside the domain and the distribution of chemical species. As 80% of the energy matrix in Brazil is generated by combustion processes and government regulations about NOx emissions are becoming more restrict, enhancing combustion efficiency in a CO boiler with a turbulent swirling flow to reduce pollutant emissions has become an engineering research topic. Enhancing mixing processes through turbulent swirling flows might reduce thermal NOx formation. Computational fluid dynamics simulations were realized using the in-house MFSim code with the turbulent closure models LES, URANS Standard k − ", URANS Standard k − " Modified and URANS Realizable k − ". A theoretical basis about turbulence, LES and URANS closure models, mixing and swirling flows was provided. A state of art comprising different authors pointed out that some works with URANS Standard k − " demonstrated a premature solid-body rotation formation due to its eddy viscosity assumption and that swirling flows may reduce pollutant emissions by improving mixing of reactants and decreasing flame temperature. Validations concerning multi-component mixing flows and Immersed Boundary method were presented. From the results, LES and URANS Standard k − " presented similar velocity field results, capable of capturing the swirling formation. When analyzing three URANS closure models, a turbulent kinetic energy graph illustrated that it is relevant to observe the modeled part and the value obtained from velocity field fluctuations. The modified model presented low turbulent viscosity values and an LES-like behavior, with similar results to the standard model. The realizable model presented distant results comparing to the other models studied and there was no reverse flow in its swirling core. Adding different chemical species did not modify the velocity field and the highest mixing level was obtained in the most intense turbulent swirling region, close to the inlets. The data provided may assist in the comprehension of swirling formation, mixture processes inside a boiler and temperature control to reduce pollutant emissionsCAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorDissertação (Mestrado)Uma simulação numérica de um escoamento turbulento não reativo em uma caldeira industrial ciclônica de CO foi investigada a fim de se compreender a formação de um escoamento rotativo, o comportamento do fluido em diferentes locais dentro do domínio e a distribuição de espécies químicas. Como 80% da matriz energética no Brasil é gerada por processos de combustão e as regulamentações governamentais sobre as emissões de NOx estão se tornando mais restritas, o aumento da eficiência da combustão em uma caldeira de CO com escoamento turbulento ciclônico para reduzir as emissões de poluentes tornou-se um tema de pesquisa de engenharia. Melhorar os processos de mistura por meio de escoamentos turbulentos rotativos pode reduzir a formação térmica de NOx. Simulações de dinâmica dos fluidos computacional foram realizadas usando o código MFSim com os modelos de fechamento turbulento LES, URANS Standard k − ", URANS Standard k − " Modificado e URANS Realizable k − ". Foi fornecida uma base teórica sobre turbulência, modelos de fechamento LES e URANS, escoamentos com mistura e escoamentos rotativos. Um estado da arte compreendendo diferentes autores apontou que alguns trabalhos com URANS Standard k − " demonstraram uma formação de rotação de corpo sólido prematura devido à sua suposição de viscosidade turbulenta e que escoamentos rotativos podem reduzir as emissões de poluentes, melhorando a mistura de reagentes e diminuindo a temperatura da chama. Foram apresentadas as validações relativas aos escoamentos com mistura de multicomponentes e ao método da Fronteira Imersa. Dos resultados, LES e URANS Standard k − " apresentaram campos de velocidade semelhantes, capazes de capturar a formação de escoamento rotativo. Ao analisar três modelos de fechamento URANS, um gráfico de energia cinética turbulenta ilustrou que é relevante observar a parte modelada e o valor obtido a partir das flutuações do campo de velocidade. O modelo modificado apresentou baixos valores de viscosidade turbulenta e comportamento semelhante a LES, com resultados similares ao modelo Standard. O modelo realizável apresentou resultados distantes em comparação com os outros modelos estudados e não houve escoamento reverso em seu núcleo giratório. A adição de diferentes espécies químicas não modificou o campo de velocidade e o maior nível de mistura foi obtido na região de turbulência mais intensa, próxima às entradas. Os dados fornecidos podem auxiliar na compreensão da formação de escoamento rotativo, processos de mistura dentro de uma caldeira e controle de temperatura para reduzir as emissões de poluentes