Paying for Biodiversity Conservation Services in Agricultural Landscapes

Adoption of improved silvopastoral practices in degraded pasture areas is thought to provide valuable local and global environmental benefits, including biodiversity conservation, However, these practices are insufficiently attractive to individual land users for them to adopt them spontaneously, particularly due to their high initial costs. This paper describes the contract mechanism developed for the Regional Integrated Silvopastoral Ecosystem Management Project, which is being implemented with financing from the Global Environment Facility (GEF). The project is testing the use of the payment-for-service mechanism to encourage the adoption of silvopastoral practices in three countries of Central and South America: Colombia, Costa Rica, and Nicaragua. The project has created a mechanism that pays land users for the global environmental services they are generating, so that the additional income stream makes the proposed practices privately profitable. Designing the mechanism required addressing issues such as (1) measuring the actual amount of environmental services being provided, so that appropriate payments can be made; (2) providing payments in a way that resulted in the desired change in land use; and (3) avoiding the creation of perverse incentives (for example, for land users to cut down existing trees so as to qualify for additional payments for tree planting). Two variants of the proposed payment mechanism are being tested, with participating land users assigned randomly to one or the other. The project also includes extensive monitoring of the effectiveness of each mechanism in stimulating adoption of the proposed measures and of the resulting impact on environmental services and on household welfare. These features, together with the three-country approach, will provide in the coming years a very rich dataset for testing the use of contract mechanisms for biodiversity conservation.Payments for Environmental Services, Contract design, Biodiversity, Conservation, Silvopastoral, Agroforestry

Avaliação da resistência ao desgaste microabrasivo das ligas de titânio Ti-12Cr e Ti-22Nb-6Zr obtidas por metalurgia do pó e recobertas com revestimento de diamante DLC

Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Mecânica, 2018.Devido a uma combinação única de propriedades desejáveis, o titânio e suas ligas têm sido amplamente utilizados em inúmeras aplicações aeroespaciais, biomédicas, químicas, marinhas e equipamentos esportivos. Tais propriedades mecânicas incluem alta relação resistência-peso, excelente resistência à corrosão, baixa densidade, alta tenacidade e excelente biocompatibilidade. Contudo, as ligas de titânio exibem baixa resistência ao desgaste abrasivo, limitando sua aplicação. O tratamento de superfície adequado expande o uso destes materiais, sendo um dos métodos mais eficientes e eficazes para melhorar a resistência ao desgaste. Os filmes de DLC (diamond-like carbon) apresentam um comportamento muito promissor, com excelentes propriedades mecânicas, tribológicas e biocompatíveis. O objetivo principal deste trabalho é estudar a influência da deposição de revestimento de carbono tipo diamante (DLC) na resistência ao desgaste microabrasivo das ligas de titânio Ti-12Cr (amostras TC1 e TC4) e Ti-22Nb-6Zr (amostras TNZ1 e TNZ4) produzidas por metalurgia do pó. As amostras nestas composições foram primeiramente sinterizadas, gerando substratos para deposição de filmes. Estes substratos foram em seguida analisados por difratometria de raios-x, apresentando as fases α-Ti e β-Ti. Não foram detectados intermetálicos dos sistemas TiCr e TiNbZr ao nível de resolução do difratômetro usado. As analises via microscopia eletrônica de varredura destes substratos mostraram microestruturas homogêneas, com baixa porosidade e alta densificação. Em ambos as composições, prevaleceram lamelas e grãos colunares bem definidos da fase alfa e matriz composta por fase β. Mapeamentos espectrais via EDS visando identificar a distribuição dos elementos nas amostras demonstraram concentração dos elementos beta- estabizadores (Nb e Cr) na matriz beta. Os revestimentos com filmes DLC foram efetuados nos substratos por PECVD (plasma enhanced chemical vapor deposition), gerando filmes com duas diferentes espessuras em cada liga. Ensaios de desgaste microabrasivo por esfera livre foram realizados nas amostras utilizando-se suspensão abrasiva de alumina (Al2O3) com concentração de 0,4 g/cm3 em água destilada e velocidade entre a superfície da esfera e a amostra de aproximadamente 0,195 m.s-1. Foram estudados também 5 diferentes modelos de equações de desgaste com intuito de verificar o que melhor se ajusta com os resultados obtidos experimentalmente, a partir dos coeficientes de determinação e correlação. Nas amostras recobertas com DLC e submetidas a ensaios microabrasivos, foram realizadas caracterizações por microscopia eletrônica de varredura (MEV), microdureza Vickers, ensaios de aderência dos filmes por endentação Rockwell C, microscopia confocal a laser e óptica, microscopia de força atômica (MFA) e espectroscopia Raman. As espessuras dos filmes depositados foram de 0,487μm para as amostras TC1 e TNZ1(filmes mais finos)e 4,23 μm para as amostras TC4 e TNZ4 (filmes espessos).Um dos 5 métodos de avaliação de desgaste (Método de Allsopp Vc/Vs) mostrou-se como o melhor modelo para a determinação dos coeficientes de desgaste para o conjunto de dados obtidos, uma vez que apresentou os coeficientes de determinação e de correlação mais próximos de 1 dentre os métodos propostos; os valores dos coeficientes de desgaste dos revestimentos Kc (método Allsopp Vc/Vs) foram 40,35% menores para a condição TNZ4 em relação ao Kc da condição TNZ1 e 53,14% menores para a condição TC4 em relação ao Kc da condição TC1, respectivamente. Portanto, os filmes mais espessos, por apresentarem menores coeficientes de desgastes, mostraram-se mais resistentes ao desgaste. Prevaleceu nestes filmes mais espessos o desgaste a três corpos, com rolamento das partículas abrasivas durante o ensaio, que é menos agressivo. Já nos filmes com menores espessuras de DLC (TNZ1 e TC1), preponderou o desgaste no modo abrasivo, mais agressivo, a dois corpos, por riscamento, onde partículas abrasivas permanecem aderidas à amostra durante o ensaio. Filmes de DLC depositados por PECVD em ligas de titânio Ti-22Nb-6Zr e Ti-12Cr produzidas por metalurgia do pó apresentam excelente desempenho tribológico nos ensaios de desgaste microabrasivo, quando comparado aos resultados obtidos para a resistência ao desgaste dos substratos sem recobrimento. Tanto os filmes mais finos (TNZ1 e TC1) quanto os mais espessos (TNZ4 e TC4) não apresentaram desplacamento dos filmes nos testes aderência por indentação Rockwell C, previstos na norma VDI 3198. Estes resultados demonstraram que o processo PECVD usado na deposição dos filmes DLC produziu fortes ligações interfaciais filmes- substratos. Os índices de qualidade dos pares filmes-substratos alcançaram a condição HF-2 da norma supracitada, indicativo de boa aderência, mesmo considerando-se que durante o teste de aderência ocorreu expressiva deformação nos substratos macios das ligas de titânio, sem provocar delaminação dos filmes. Os resultados da analise Raman demonstram que a deposição PECVD usada neste trabalho foi efetiva, produzindo compostos de carbono mistos sp2 e sp3, característicos de filmes carbono tipo diamante, para ambas as espessuras de revestimentos. Desta forma, os filmes em ambas as espessuras forneceram boa qualidade estrutural, homogeneidade na rugosidade superficial Ra, alta dureza, excelente aderência filme-substrato. O filme mais espesso apresentou maior resistência ao desgaste microabrasivoTitanium and its alloys have been used in several applications such as aerospace, biomedical, chemical, maritime e sport devices, due to its singular properties. These properties include high strength-to- weight ratio, excellent corrosion resistance, low density, high toughness and good biocompatibility. However, titanium alloys have low wear resistance, hindering its applications. An adequate surface treatment to improve wear resistance can extend the use of these materials. Films such DLC (diamond like carbon) show promising performance, with excellent mechanical, wear resistance and biocompatible properties. The main objective of this work is to evaluate the influence of DLC films at the micro-abrasive resistance of the titanium alloys Ti-Cr (samples TC1 and TC4) and Ti-22Nb-6Zr (TNZ1 e TNZ4) produced by powder metallurgy. Samples of these compositions were firstly sintered and evaluated by x-ray diffractometry, showing α-Ti and β-Ti phases. Intermetallics were not identified at the resolution level of the equipment. Scanning electron microscopy at these substrates showed homogeneous microstructures, with low porosity and high densification. In both compositions columnar grains prevailed at alfa phase. Mapping with EDS showed concentrations of beta stabilizers (Nb and Zr) in beta matrix. The application of DLC films were made via PECVD (plasma enhanced chemical vapor deposition), giving rise to films with two different thicknesses for each alloy. Tests of micro-abrasive wear used free ball and abrasive suspension of alumina (Al2O3) with concentration of 0,4 g/cm3 and distilled water with sphere speed of 0,195 m.s-1. Five different models of wear equations were studied, aiming the evaluation of the best experimental adjustment, using correlation and determination coefficients. Characterization of coated samples were carried out using scanning electron microscopy, Vickers hardness, adhesion test with Rockwell indentation, confocal and optical microscopy, atomic force microscopy and Raman spectroscopy. The obtained films thickness were 0,487 μm for TC1 and TNZ1 and 4,23μm for TC4 and TNZ4 samples. The best abrasive wear equation for abrasive wear determination was the Allsopp Vc/Vs, considering the best fit with correlation and determination coefficients. The values of wear coefficients Kc were 40,35 times lower for TNZ4 compared to TNZ1 and 53,14% lower for TC4 condition compared to TC1, respectively. Therefore, thicker films are more resistant to wear, considering its lower wear coefficients. Tree body wear prevails for these thicker films with rolling wear. For thinner films, two body abrasive wear were observed, where abrasive particles remained bonded to the sample during wear tests. DLC films applied by PECVD at titanium alloys showed excellent wear performance at micro abrasive wear tests. Both films showed good performance at Rockwell adhesion test according VDI 3198 standard. These results demonstrates that PECVD coating process produces strong interfacial bonds film – substrates, with HF-2 quality, indicative of good adhesion film-substrate. Raman analysis showed sp2 and sp3 carbon composite, characteristics of diamond like carbon films. Therefore, both films showed good structural quality, homogeneity at surface roughness, high hardness, and excellent adhesion. The thicker film showed higher wear resistance

Plan de negocios para la organización de una empresa dedicada a la gestión y producción de indumentaria deportiva de clubes a nivel provincial

La empresa que se propone estará dedicada a la gestión y producción de indumentaria deportiva de clubes a nivel provincial. Específicamente, orientada al diseño, producción y venta de indumentaria (fútbol y deportes accesorios). Estará dirigida al mercado de la provincia de Mendoza, se toma como nicho de mercado tanto a los afiliados, como también a todos los prospectos simpatizantes de los clubes locales que se toma como referencia. Se espera una rápida recuperación de las inversiones, permitiendo obtener un margen de ganancia en el corto plazo. Los indicadores de VAN $ 625.414 Y TIR 120%. La propuesta de valor a los clubes locales a través de una estrategia de nicho basada en la diferenciación, permitiendo responder a las necesidades insatisfechas presentadas por la hinchada del club. Se puede concluir que el mismo es factible desde el punto de vista técnico, económico, organizacional y comercial.Fil: Gobbi, Federico Jos

Improvement of mechanical properties and corrosion resistance of 316L and 304 stainless steel by low temperature plasma cementation

Low temperature plasma carburizing treatment of austenitic stainless steels is a carbon surface diffusion process for a surface hardness and corrosion and wear resistance. The process is carried out by introducing a mixture of carbon-containing gases and through the use of low temperatures the resulting cemented layer usually contains a single phase of supersaturated austenite with carbon – S-phase. For the present investigation, austenitic stainless steels AISI 316L and 304 were plasma cemented for 8 hours in the gas mixture containing 7.5% CH4 in H2, with a pressure of 500 Pa, at temperatures of 375 ºC and 450 ºC. The phases formed were determined by X-ray diffraction. The corrosion resistance was evaluated through immersion tests over time and cyclic voltammetry. The results indicate that there was no formation of compounds (carbides) in the cemented layer for both steels at any of the temperatures and there was a corrosion resistance improvement. Keywords: plasma carburizing, AISI 304, AISI 316L, corrosion

Guanaco’s diet and forage preferences in Nothofagus forest environments of Tierra del Fuego, Argentina

Aim of study: Guanaco (Lama guanicoe Müller), is a South American native ungulate widely distributed in Patagonia, which in the island of Tierra del Fuego (TF), extends its habitat into Nothofagus spp. forests. Within these forests, guanacos consume lenga (Nothofagus pumilio) leaves and twigs, and other understory species. The aim of this work was to determine: 1) the spring and summer diet of free ranging guanacos, and 2) which plants, grown in the forest understory, guanacos do prefer, or avoid, in these seasons of great forage abundance.Area of study: Tierra del Fuego (Argentina), on three representative areas which combined Nothofagus forests and adjacent meadows (vegas).Material and Methods: Guanacos’ diet was determined by comparing epidermal and non-epidermal plant fragments with micro-histological analyses of feces. The analysis was made from composite samples of fresh feces, collected at the seasons of maximum forage productivity (spring and summer).Main results: During spring, 48% of guanacos’ diet was composed of lenga leaves, 30% of grass-like species, 15% of grasses, and less than 7% of herbs, shrubs, and lichens. In summer, 40% of the diet was composed of grasses, 30% of lenga leaves, 25% of grass-like species and the rest corresponded to herbs, shrubs, and lichens. Within the forest understory, guanaco selected lenga leaves and twigs, grass species were consumed according to their availability (or sometimes rejected), while other herbs were not consumed at all.Research highlights: Guanacos’ consumption preference for lenga, even considering the high availability of other forages, could adversely affect forest regeneration

Aerosol characterization in Northern Africa, Northeastern Atlantic, Mediterranean Basin and Middle East from direct-sun AERONET observations

We provide an atmospheric aerosol characterization for North Africa, Northeastern Atlantic, Mediterranean and Middle East based on the analysis of quality-assured direct-sun observations of 39 stations of the AErosol RObotic NETwork (AERONET) which include at least an annual cycle within the 1994–2007 period. We extensively test and apply the recently introduced graphical method of Gobbi and co-authors to track and discriminate different aerosol types and quantify the contribution of mineral dust. The method relies on the combined analysis of the Ångström exponent (α) and its spectral curvature δα. Plotting data in these coordinates allows to infer aerosol fine mode radius (Rf) and fractional contribution (η) to total Aerosol Optical Depth (AOD) and separate AOD growth due to fine-mode aerosol humidification and/or coagulation from AOD growth due to the increase in coarse particles or cloud contamination. Our results confirm the robustness of this graphical method. Large mineral dust is found to be the most important constituent in Northern Africa and Middle East. Under specific meteorological conditions, its transport to Southern Europe is observed from spring to autumn and decreasing with latitude. We observe "pure Saharan dust" conditions to show AOD>0.7 (ranging up to 5), α1.5 and δα~−0.2 corresponding to η>70% and Rf~0.13 μm. Here, dust mixed with fine pollution aerosols shifts the observations to the region α<0.75, in which the fine mode contribution is less than 40%.This work was funded by the project CICYT CGL2006-11879 of the Spanish Ministry of Education and Science. GPG activity was partly supported by the AEROCLOUDS project, funded by the Italian Research Ministry

El seguro de caución

El presente trabajo busca aclarar algunos de los principales cuestionamientos que se presentan en la actualidad al contratar un seguro de caución. Específicamente se busca dirimir y definir la esencia y naturaleza jurídica del seguro de caución respecto de otras figuras, para finalmente encuadrarlo como seguro de garantía o fianza, lo que definirá su legislación, derechos y obligaciones.Fil: Corvalán, Marcelo Adrían . Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Cucchi Azar, Juan Martín. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Ferrando, Lucas Mario. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Ferreyra, José Daniel. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas.Fil: Gobbi, Federico. Universidad Nacional de Cuyo. Facultad de Ciencias Económicas

Aerosol characterization in Northern Africa, Northeastern Atlantic, Mediterranean Basin and Middle East from direct-sun AERONET observations

We proviede an atmospheric aerosol characterization for North Africa, Northeastern Atlantic, Mediterranean and Middle East based on the analysis of quality-assured direct-sun observations of 39 stations of the AErosol RObotic NETwork (AERONET) which include at least an annual cycle within the 1994–2007 period. We extensively test and apply the recently introduced graphical method of Gobbi and co-authors to track and discriminate different aerosol types and quantify the contribution of mineral dust. The method relies on the combined analysis of the Ångström exponent (α) and its spectral curvature δα. Plotting data in these coordinates allows to infer aerosol fine mode radius (Rf) and fractional contribution (η) to total Aerosol Optical Depth (AOD) and separate AOD growth due to fine-mode aerosol humidification and/or coagulation from AOD growth due to the increase in coarse particles or cloud contamination. Our results confirm the robustness of this graphical method. Large mineral dust is found to be the most important constituent in Northern Africa and Middle East. Under specific meteorological conditions, its transport to Southern Europe is observed from spring to autumn and decreasing with latitude. We observe "pure Saharan dust" conditions to show AOD>0.7 (ranging up to 5), α1.5 and δα~−0.2 corresponding to η>70% and Rf~0.13 μm. Here, dust mixed with fine pollution aerosols shifts the observations to the region α<0.75, in which the fine mode contribution is less than 40%.Peer ReviewedPostprint (published version

Brazilian soccer players and no-players adolescents: effect of the maturity status on the physical capacity components performance

The aim of this study was to compare the speed and the agility between Brazilian soccer players and non-players, regarding maturity status in adolescents 11-15 years old. Forty and two soccer players (age – 159.30±17.28 months old; weight – 48.45±9.96 kg; height – 1.53±0.10 m) and 45 non-players (age – 162.62±24.92 months old; weight – 48.30±8.35 kg; height – 1.54±0.12 m) participated of this study. Participants were classified by maturity status. On 2 different days with 1 week of differences between the assessments the participants were evaluated the agility, by Shuttle Run test, and the speed, by 30 m maximum speed test. The results showed that the maturity status was an influential factor in the performance with better results for individuals in a more advanced stage. The soccer practice does not seem to interfere in the performance of the physical capacity components analyzed, only effective when different maturity levels are involved in the analysis. It is also possible that late maturing boys selectively drop-out of soccer as age and sport specialization increase