Technical efficiency for a sample of Chilean wine grape producers: A stochastic production frontier analysis

Troncoso, JL (Troncoso, Javier L.) Univ Talca, Dept Agr Econ, Talca, Chile. ; Bravo-Ureta, BE (Bravo-Ureta, Boris E.) Univ Connecticut, Storrs, CT 06269 USATechnical efficiency for a sample of Chilean wine grape producers: A stochastic production frontier analysis. Cien. Inv. Agr. 38(3):321-329. Chile has become an increasingly important player in international wine markets. Concurrent with the expansion of Chilean wine output and exports, there has been an increase in production in several other "New World" countries including Argentina, Australia, New Zealand and South Africa. The overall growth in wine supplies has increased competition to capture market share, which highlights the importance of productivity gains among wine and grape producers. The purpose of this paper is to estimate and analyze the technical efficiency (TE) component of productivity for a sample of wine grape producers in Chile. The data includes 38 farms with specific input-output information for individual blocks yielding a total of 263 observations. We use a Cobb-Douglas model to estimate a stochastic production frontier (SPF) and to obtain TE scores both at the individual block and at the farm level. The results suggest that the average farm level TE is 77.2%, while the block level TE ranges from 23.4 to 95.0%. The value of the function coefficient is 1.021, which suggests nearly constant returns to size

Wave profile and tide monitoring system for scalable implementation

Apresentação de Poster em conferência Nacional.Presentation of a wave profile and tide monitoring system, with low-cost and low-power pressure sensors connected to a datalogger in a wired or acustic network

Spin Glass Behavior in RuSr2Gd1.5Ce0.5Cu2O10

The dynamics of the magnetic properties of polycrystalline RuSr2Gd1.5Ce0.5Cu2O10 (Ru-1222) have been studied by ac susceptibility and dc magnetization measurements, including relaxation and ageing studies. Ru-1222 is a reported magneto-superconductor with Ru spins magnetic ordering at temperatures near 100 K and superconductivity in Cu-O2 planes below Tc ~ 40 K. The exact nature of Ru spins magnetic ordering is still debated and no conclusion has been reached yet. In this work, a frequency-dependent cusp was observed in ac susceptibility vs. T measurements, which is interpreted as a spin glass transition. The change in the cusp position with frequency follows the Vogel-Fulcher law, which is commonly accepted to describe a spin glass with magnetically interacting clusters. Such interpretation is supported by themoremanaent magnetization (TRM) measurements at T = 60 K. TRM relaxations are well described by a stretched exponential relation, and present significant ageing effects.Comment: 4 pages, 6 figures, submitted to Phys. Rev.

Durability assessment of external thermal insulation composite systems in urban and maritime environments

External Thermal Insulation Composite Systems (ETICS) are multilayer solutions which provide an enhanced thermal performance to the building envelope. However, significant anomalies can be detected on ETICS facades, in some cases shortly after the application of these systems. This study intends to evaluate and compare the durability of six commercially available ETICS after two years of outdoor exposure at both urban and maritime conditions in Portugal. The systems were characterized by means of non-destructive testing (i.e., visual and microscopic assessment, water transport properties, thermal conductivity, surface roughness), thus allowing to evaluate the performance loss throughout natural aging. The bio-susceptibility and aesthetic properties (color and gloss) were also investigated. Results showed that the performance and durability of the complete system is significantly affected by the rendering system formulation. The lime-based specimens obtained the highest rate of mold development after one year of aging in a maritime environment, becoming considerably darker and with lower surface gloss. Fungal analysis of this darkish stained area indicated the presence of mold species of the genera Alternaria, Didymella, Cladosporium and Epicoccum, and yeasts of the genera Vishniacozyma and Cystobasidium. An increase of both capillary water absorption and water vapor permeability was also registered for the aged lime-based specimens. Acrylic-based systems obtained lower capillary water absorption after aging and greater dirt deposition on their surfaces, especially in urban conditions. These systems had also higher color variation and surface gloss decrease and slightly higher mold growth, when compared with those aged in a maritime environment. Finally, no mold growth was detected on the silicate-based specimens after two years of aging. However, these specimens obtained higher capillary water absorption and lower vapor permeability after aging, possibly leading to moisture accumulation within the system. Results contribute towards the development of ETICS with enhanced performance and durability.info:eu-repo/semantics/publishedVersio

5. Impacto del cambio climático en la sedimentación y en la acumulación de carbono en los lagos de la Amazonia peruana

Los suelos, las aguas y los sedimentos de la cuenca amazónica son importantes compartimentos del ciclo de carbono, el cual se encuentra parcialmente almacenado en los bosques inundables y en los lagos de inundación de la región (20% de la superficie total de la cuenca). Estudiar los procesos de sedimentación lacustres a diferentes escalas espaciales y de tiempo permite mejorar le estimación del balance biogeoquímico del carbono (uno de los gases de efecto Invernadero responsable del cambio climático actual, el CO2). Las tasas de sedimentación en las áreas de inundación dependen de varios factores, como el tipo de agua de los lagos y del tipo de conexión que tienen con los ríos. El análisis en laboratorio de muestras de sedimentos, que mantienen la secuencia de deposición, sirve para determinar las condiciones geológicas, meteorológicas, los cambios en el ecosistema e incluso acciones de origen humano que pueden haber afectado los regímenes de sedimentación y la composición de los sedimentos a lo largo del tiempo.Les sols, les eaux et les sédiments du bassin amazonien sont des compartiments importants du cycle du carbone, qui est partiellement stocké dans les forêts et les lacs inondés dans la région (20% de la superficie totale du bassin). Connaître les processus de sédimentation lacustres à différentes échelles spatiales et temporelles permet d'améliorer l'estimation de l'équilibre biogéochimique du carbone (un des gaz responsables du changement climatique actuel, CO2). Les taux de sédimentation dans la plaine inondable dépendent de plusieurs facteurs, y compris le type d'eau des lacs et le type de connexion avec les rivières. Les analyses de laboratoire des échantillons de sédiments, qui maintiennent la séquence de dépôt, sont utilisées pour déterminer les caractéristiques géologiques, les conditions météorologiques, les changements dans l'écosystème et même les actions humaines qui peuvent avoir une incidence sur les régimes de sédimentation et la composition des sédiments au fil du temps.The soils, waters and sediments of the Amazon basin are important compartments of the carbon cycle, which are partially stored in flooded forests and lakes of flooding in the region (20% of the total basin area). The study of lacustrine sedimentation processes at different spatial and temporal scales allows improving the estimation of biogeochemical carbon balance (one of the greenhouse gases responsible for the current climate change, CO2). Sedimentation rates in flood areas depend on several factors, such as the type of water from lakes and the type of connection this water has with rivers. The laboratory analysis of sediment samples, which maintain the deposition sequence, is used to determine geological and meteorological conditions; as well as changes in the ecosystem, even actions arising from humans that may have affected the sedimentation regimes and sediment composition along the time

Debate sobre o artigo de Narvai et al.

English title: Debate on the paper by Narvai et al.Margareth Crisóstomo Portela & Mauricio Teixeira Leite de Vasconcello

Population overlap and habitat segregation in wintering Black-tailed Godwits Limosa limosa

Distinct breeding populations of migratory species may overlap both spatially and temporally, but differ in patterns of habitat use. This has important implications for population monitoring and conservation. To quantify the extent to which two distinct breeding populations of a migratory shorebird, the Black-tailed Godwit Limosa limosa, overlap spatially, temporally and in their use of different habitats during winter. We use mid-winter counts between 1990 and 2001 to identify the most important sites in Iberia for Black-tailed Godwits. Monthly surveys of estuarine mudflats and rice-fields at one major site, the Tejo estuary in Portugal in 2005-2007, together with detailed tracking of colour-ringed individuals, are used to explore patterns of habitat use and segregation of the Icelandic subspecies L. l. islandica and the nominate continental subspecies L. l. limosa. In the period 1990-2001, over 66 000 Black-tailed Godwits were counted on average in Iberia during mid-winter (January), of which 80% occurred at just four sites: Tejo and Sado lower basins in Portugal, and Coto Dontildeana and Ebro Delta in Spain. Icelandic Black-tailed Godwits are present throughout the winter and forage primarily in estuarine habitats. Continental Black-tailed Godwits are present from December to March and primarily use rice-fields. Iberia supports about 30% of the Icelandic population in winter and most of the continental population during spring passage. While the Icelandic population is currently increasing, the continental population is declining rapidly. Although the estuarine habitats used by Icelandic godwits are largely protected as Natura 2000 sites, the habitat segregation means that conservation actions for the decreasing numbers of continental godwits should focus on protection of rice-fields and re-establishment of freshwater wetlands

Identifying and explaining the farming system composition of agricultural landscapes: The role of socioeconomic drivers under strong biophysical gradients

In mountain landscapes, agricultural abandonment is taking place in the most vulnerable areas, while intensification increases in the most productive lands. These contrasting processes, which have different impacts on biodiversity and ecosystem services (BES), are related to changes in the farming system component of these landscapes. Farming systems are identified based on farmer’s decisions on, for example, type of crop and level of fertilizers, which represent the descriptors of farming systems and can be grouped into several dimensions (e.g. land use and intensity). Since obtaining this data at farm-level is often difficult, an alternative is to study the spatial combinations of farming systems at parish-level, i.e., Farming System Mixes (FSM), relying on agricultural census data. Other biophysical (e.g. climate, soil) and socioeconomic (e.g. labour, farmer’s age) variables, independent of farmers' decisions, represent the exogenous drivers of these decisions. The separation between descriptors and drivers is important to improve knowledge about what drives farmers' decisions regarding farming system choice, as these choices are often the focus of policies aiming the support of BES. In this study, we explored the underlying drivers of FSM and assessed the role of socioeconomic drivers, main target for policy makers, in a context of strong biophysical gradients. Biophysical drivers emerge as those that primarily discriminate between the FSM located in different topographic positions (valleys, mountains and plateau). In the situations where there is a greater range of productive choices available for farmers, such as in valleys, socioeconomic drivers assume a preponderant role on farming system choiceinfo:eu-repo/semantics/publishedVersio