155 research outputs found
Wavelet analysis of a Sentinel-2 time series to detect land use changes in agriculture in the Vega Alta of the Guadalquivir River: Cantillana case study (Seville)
Historically, the Vega Alta of the Guadalquivir River (southern Spain) has been an anthropized space. Over time, the dominance of latifundia agriculture has evolved towards more intensive citrus-based agriculture. In this study, wavelet algorithms applied to Sentinel-2 time series were used to determine both the expansion of citrus plantations and the level of intensification of these plantations within the municipality of Cantillana. Sentinel-2 provides comprehensive global coverage from March 2017 to the present. Our study applied a 90% power wavelet transformation for the creation of a wavelet-smoothed time series for four years of Sentinel-2 NDVI data. Based on the data, it can be stated that within our research region covering 5000 hectares of agricultural land, over a span of four years (2017 to 2020), more than 980 hectares of native vegetation and pasture were transformed into citrus orchards, giving rise, at the end of 2020, to a total area of 3250 ha. Analyzing unique spatial patterns within a wavelet-smoothed time series data is very useful for land management, as it allows land use changes to be controlled. For this reason, it becomes feasible to assess the reliability of the wavelet method using both remote sensing and GIS tools
Inverse Opal CuCrO2 Photocathodes for H2 Production Using Organic Dyes and a Molecular Ni Catalyst.
Dye-sensitized photoelectrochemical (DSPEC) cells are an emerging approach to producing solar fuels. The recent development of delafossite CuCrO2 as a p-type semiconductor has enabled H2 generation through the coassembly of catalyst and dye components. Here, we present a CuCrO2 electrode based on a high-surface-area inverse opal (IO) architecture with benchmark performance in DSPEC H2 generation. Coimmobilization of a phosphonated diketopyrrolopyrrole (DPP-P) or perylene monoimide (PMI-P) dye with a phosphonated molecular Ni catalyst (NiP) demonstrates the ability of IO-CuCrO2 to photogenerate H2. A positive photocurrent onset potential of approximately +0.8 V vs RHE was achieved with these photocathodes. The DPP-P-based photoelectrodes delivered photocurrents of -18 μA cm-2 and generated 160 ± 24 nmol of H2 cm-2, whereas the PMI-P-based photocathodes displayed higher photocurrents of -25 μA cm-2 and produced 215 ± 10 nmol of H2 cm-2 at 0.0 V vs RHE over the course of 2 h under visible light illumination (100 mW cm-2, AM 1.5G, λ > 420 nm, 25 °C). The high performance of the PMI-constructed system is attributed to the well-suited molecular structure and photophysical properties for p-type sensitization. These precious-metal-free photocathodes highlight the benefits of using bespoke IO-CuCrO2 electrodes as well as the important role of the molecular dye structure in DSPEC fuel synthesis
Characterisation of organic beef cattle farms in Andalusia
The structure of organic beef cattle farms located in Andalusia have been characterised from a stratified survey including 10% of official census. Farms are specialized in raising steers and use native breeds. The mean surface of farms is 524 ha and they have 99 cows. They are multifunctional systems located in the dehesa, where cattle commonly graze alongside other species like Iberian pigs. These farms correspond to a production model in which the land is extremely important in the production of food for the cattle, using strategic or seasonal food supplementation in periods of shortage. Average stocking is 0.43 animals/ha, lower than those proposed by Orden de 4 de febrero del 2004 (Consejería de Agricultura y Pesca), corresponding to a farming activity adapted to the environment. Likewise, the mean productivity of these farms is scarce (with an index of commercial calves of 80% and a mortality rate of 5.26%). These farms have a commercial target where the non-familiar workforce predominates, and the workforce amounts to 1.56 AWU per farm. These farms sell all calves after weaning to livestock traders, who take them to other regions for conventional fattening until slaughter. It is necessary to develop organic commercial trails to guarantee the future of the sector.El objetivo del estudio es una aproximación a la caracterización productiva del vacuno ecológico de orientación cárnica en Andalucía. Se realiza un muestreo estratificado del 10% de la población encontrando los siguientes resultados: Las explotaciones se orientan a la producción de terneros al destete, utilizando razas autóctonas y sus cruces. Se localizan en la dehesa y presentan un carácter multifuncional, donde predomina la asociación con cerdo Ibérico. La explotación media presenta en torno a 524 ha y 99 vacas presentes. El sistema de alimentación se sustenta en la utilización de pastos y otros recursos de la dehesa, que se complementan con suplementación estratégica estacional. La carga ganadera media se cifra en torno a las 0,43 UGM/ha, valores inferiores a los recogidos en la Orden de 4 de febrero del 2004 de la Consejería de Agricultura y Pesca y que se corresponden con unas prácticas de producción respetuosas y compatibles con el medio ambiente. Asimismo la productividad es de 0,8 terneros comerciales por vaca presente, la tasa de reposición supera el 10%; en tanto que, la mortalidad asciende al 5,26%. Estas explotaciones tienen orientación comercial, con mano de obra asalariada en la mayor parte de los casos (1,56 UTH por explotación). Los terneros se destinan a cebaderos convencionales ante la ausencia de canales ecológicos, por lo que es necesario reconducir los procesos de cebo ecológico, desarrollando canales de comercialización apropiados (integraciones horizontales), con el objetivo de cerrar el ciclo y garantizar el futuro del sector
Caracterización social y comercial de los sistemas ovinos y caprinos de la región noroeste de República Dominicana
A fin de estudiar los aspectos sociales y comerciales que caracterizan
al sistema de producción de ovinos y caprinos de la
región noroeste de República Dominicana, se muestrearon 94
explotaciones (24% de la población), aplicando el método de
encuesta directa mediante muestreo aleatorio estratificado con
asignación proporcional. Las explotaciones que conforman este
sistema ganadero son en un 82% familiares, con antigüedad en
torno a 16 ±1,3 años. El 93% de los propietarios son hombres,
con edad media de 51 ±1,2 años, el 63% ha iniciado estudios
primarios y 8% no ha realizado estudios. El régimen de tenencia
de tierra está relacionado al tipo de explotación según la especie
productiva (p<0,05); el 84% de las explotaciones caprinas se desarrollan
en tierras públicas y las explotaciones ovinas y mixtas
hacen mayor uso de terrenos privados. Para 53% de los propietarios
la producción de ovinos y caprinos constituye la actividad
principal y 78% de las explotaciones utiliza mano de obra
familiar. La comercialización se efectúa mediante canales largos
con los carniceros (70%), mientras el 14% de las explotaciones
vende directamente al consumidor. El sistema estudiado se caracteriza
por explotaciones familiares, cuyos propietarios presentan
edad avanzada, bajo nivel de formación, alta dependencia
de terrenos públicos y escasa participación activa del productor
en la comercialización. Esta situación limita el acceso al crédito
y la adopción e innovación tecnológica. Finalmente, se considera
que el fomento del asociacionismo podría ayudar a superar
estas restricciones.In order to study the social and commercial aspects that
characterize the sheep and goat cattle production systems in
the Northwestern region of the Dominican Republic, 94 farms
(24% of the population) were sampled, applying the direct
survey method through random sampling with proportional
weighting. The farms comprising this cattle system are 82%
family owned, with a standing of 16 ±1.3 years. Of the owners,
93% are men, with average age of 51 ±1.2 years; 63%
began primary schooling and 8% did not go to school. The
land ownership regime is related to the type of exploitation
according to the productive species (p<0.05); 84% of goat
farms are on public land, and sheep and mixed farms make a larger use of private lots. For 53% of the owners the production
of sheep and goats is their main activity and 75% of
the farms use family labor. Marketing is carried out through
long channels to butchers (70%), while 14% of the farms sell
directly to consumers. The system under study is characterized
by family farms whose owners are of advanced age, low
training level, with a high dependency on public land y meager
participation of the producer in marketing. This situation
limits access to credit, as well as technological adoption and
innovation. Finally, it is considered that the promotion of associations
could help overcome such restriction
Caracterización estructural del sistema ovino-caprino de la región noroeste de República Dominicana (Structural characterization of sheep and goat farming systems in Northwest Dominican Republic)
The aim of this study was to analyze structural aspects of goat and ovine livestock farming systems located in the Norwest of Dominican Republic. The sample (94 farms) was randomly selected with proportional allocation by region. Forty-four variables related to structural and productive aspects were analyzed. The average size of farms was 96 ha and 165 animals. Their facilities are simple, nonspecific and barely functional, with a mean of 2 pens per farm. Farms generally do not have perimeter fences, facilities for breeding, feeding or watering points. The reproductive strategy is the natural breeding throughout the year on most farms, with a ratio of one sire for every 36 females, and there are no breeding records. The first mating takes place with an average weight of 17 kg at 6.5 months of age. Feeding is based on grazing of natural pastures and forests (94%), reaching a stocking density of 0.83 LU/ha. Food supplementation is used in 37% of farms, mainly in sheep and mixed farms. The lambs and goats are sold when they reach 23 kg in weight, around 7 months of age. The farms do not receive technical advice, although 94% of them apply preventive treatments on a regular basis. The mortality rate reached 12%. In general, farms are very heterogeneous in their production structure, management, nutrition and health. Thus, a group of farms developed a traditional system (goats), while the most efficient and technified correspond to sheep and mixed farms
Commercial circuits of organic milk in seven spanish regions
A major concern for organic dairy farms is to develop specific commercial circuits who guarantee the flow of organic products to the consumers. Therefore, the commercial circuits for organic milk are analysed. Actually, 11.5 millon litres of organic milk are produced in Spain, of which 5% are commercialised by conventional milk. The rest is commercialised as an organic circuit with two differentiated channels. Firstly, the long channel that absorbed 70% of organic milk and displays a conventional structure. The average price perceived by litre of organic milk rise to 0.44 euros. Secondly, the short channel that receives 26% of production. The prices in this channel rise to an average of 1,66 euros/l.Un aspecto de suma importancia para la producción ecológica es el desarrollo de circuitos comerciales que garanticen el flujo de productos ecológicos a los consumidores. En el presente trabajo se analizan los canales comerciales de leche ecológica de vaca. Actualmente la producción de leche ecológica en España se estima en 11,5 millones de litros, de los que el 5% se comercializa como leche convencional. El 95% restante sigue un circuito ecológico con dos canales bien diferenciados. En primer lugar, un 70% de la leche ecológica se comercializa a través del canal largo, que presenta una estructura convencional. El precio medio percibido asciende a 0,44 euros por litro de leche ecológica, lo que supone un incremento del 30% respecto al precio de la leche convencional. En segundo lugar, el circuito corto, que absorbe el 26% de la leche ecológica e incrementa el precio percibido hasta 1,66 euros/l, que además repercute en la renta final del ganadero
Technical and economical study of two tropical leguminous forages to feed dairy cows in the NW region of Dominican Republic
Two tropical leguminous forages are used as a partial substitute of the concentrate feed to milk production and its viability in the Northwest region of Dominican Republic is studied. Twelve dairy cows are used (crosses between Holstein and Brown Swiss and Jersey) in a fully random experimental design, with three treatments and four repetitions. In treatment I feed supplementation was 8 kg of concentrate per cow and day; while, in treatment II animals were fed with 4 kg of concentrate and 5 kg DM of leguminous forages. Treatment III supplementation was 4 kg of concentrate and a grass-leguminous forage mixture ad libitum. The experiment was carried out during 10 weeks and an individual milk production control was realised every day during this time. Results don"t show significant differences (p³0,05) for individual production neither accumulated one respecting the three proposed treatments. The study of gross margin according to treatment don’t show significant differences (p³0,05). However, simulation analysis of scenes for treatment I shows a high sensibility to modify the price of variable factor (concentrate). On the other hand, the treatment II showed superior margin and high stability to the price variation for inputs and outputs, and so was the treatment of choice in all the scenes simulated independently of milk and concentrate prices.Se estudió la utilización de leguminosas forrajeras tropicales como sustitutivo parcial del concentrado en la producción lechera y su viabilidad en la región noroeste de la República Dominicana. Se utilizan 12 vacas lecheras (cruces de Holstein con Pardo Suizo y Jersey) en un diseño experimental aleatorio con tres tratamientos y cuatro repeticiones. En el tratamiento I se suplementa con 8 kg de concentrado por vaca y día; en tanto que, en el tratamiento II se suplementan con 4 kg de concentrado y 5 kg de materia seca (MS) de una leguminosa forrajera tropical. En el tratamiento III se aporta una suplementación de 4 kg de concentrado y una asociación de una gramínea y otra leguminosa tropical ad libitum. La experiencia se desarrolló durante 10 semanas y cada día se realizó el control lechero individual. Los resultados muestran la ausencia de diferencias significativas (p³0,05) en la producción individual y acumulada respecto a los tres tratamientos propuestos. Al enfrentar el margen bruto respecto al tratamiento no se observan diferencias significativas (p³0,05). No obstante el análisis de simulación de escenarios muestra que el tratamiento I es muy sensible a la modificación del precio del factor variable (concentrado). Por otro lado, el tratamiento II presenta margen superior y alta estabilidad ante la variación de los precios de los insumos/productos y se muestra como tratamiento de elección en todos los escenarios simulados independientemente de los precios de la leche y el concentrado
La gestión del patrimonio construido a través del proyecto HBIM: un estudio de caso de pavimentos y alicatados
[EN] Building Information Modelling (BIM) is a collaborative system that has been fully developed in the design and management of industries involved in Architecture, Engineering and Construction (AEC) sectors. There are, however, very few studies aimed at managing information models in the field of architectural and cultural heritage interventions. This research therefore proposes an innovative methodology of analysis and treatment of the information based on a representative 3D graphic model of the flooring and wall tiling of a historic building. The objective is to set up a model of graphic information which guarantees the interoperability of the aforementioned information amongst the diverse disciplines intervening in the conservation and restoration process. The Pavillion of Charles V, a Renaissancecharacterised building located in outdoor areas of the Alcazar of Seville, Spain, was selected for the study. This work constitutes a project of intervention based on Heritage or Historic Building Information Modelling, called the “HBIM Project”.[ES] El Modelado de Información para la Construcción (BIM) es un sistema colaborativo que actualmente está plenamente
desarrollado en el diseño y la gestión de las industrias involucradas en el sector de la Arquitectura, Ingeniería y
Construcción (Architecture, Engineering and Contruction- AEC). En cambio, en el ámbito de las intervenciones en el
Patrimonio Cultural y Arquitectónico, son muy pocos los estudios dedicados a gestionar modelos de información. Por
ello, esta investigación propone una metodología innovadora de análisis y tratamiento de la información basada en un
Modelo gráfico 3D representativo de pavimentos y alicatados de un Edificio Histórico. La finalidad es crear un modelo de
información gráfica que garantice la interoperabilidad de dicha información entre las diversas disciplinas que intervienen
en el Proceso de Conservación y Rehabilitación Patrimonial. Para el estudio, se ha seleccionado el Cenador de Carlos V
(o de la Alcoba); edificio de carácter renacentista perteneciente a los espacios exteriores del Alcázar de Sevilla, España.
Este trabajo constituye un proyecto de intervención basado en un modelo de información patrimonial o del edificio
histórico, denominado “Proyecto HBIM”.The authors wish to thank Prof. Tabales of the Departamento de Construcciones Arquitectónicas II of the University of Seville for his major contribution and help, and Mr. Jacinto Pérez Elliot, Director-Conservador del Patronato de los Reales Alcázares de Sevilla, for granting access to the aforementioned buildings.Nieto, JE.; Moyano, JJ.; Rico Delgado, F.; Antón García, D. (2016). Management of built heritage via HBIM Project: A case of study of flooring and tiling. Virtual Archaeology Review. 7(14):1-12. doi:10.4995/var.2016.434911271
RAEA-Heliciculture: mechanism of conservation and rural development in Andalusia
The fast growth system is a snail rearing method with a high degree of technification. Actually, the experimental evaluation of the system is being developed by an Andalusian Network of Agrarian Research (RAEA-Heliciculture) on commercial farms. The aim of this study was to compare the fast growth and the intensive systems in juvenile Helix aspersa snails. The growth and the growth patterns are studied in 5 groups of 60 H. aspersa snails reared with both systems. The snails reared with the fast growth system reached a high weight (0.956 g) and a low variability (13%). The growth rate with the fast growth system showed the best fit to exponential model, while the growth rate with the intensive system showed good fit to logistic model.El sistema de pronto engorde es una especialización productiva en la fase de crecimiento y engorde de Helix aspersa con alto nivel de tecnificación. Actualmente se está desarrollando su evaluación experimental en granjas comerciales, a través de una Red Andaluza de Experimentación Agraria (RAEA-Helicicultura). Con el objetivo de comparar el sistema de pronto engorde frente al intensivo, se estudia el crecimiento y su modelización en 5 lotes de 60 caracoles H. aspersa criados con ambos sistemas durante la fase juvenil. Los resultados muestran que los caracoles del sistema de pronto engorde alcanzan el peso más alto con 0,956 g y la menor variabilidad (13%). El crecimiento con el pronto engorde se ajusta a un modelo exponencial, mientras que el sistema intensivo muestra mayor bondad en el ajuste con el modelo logístico
Typology of cattle fattening systems in the Pampa region, Argentine
The objective of the study is the identification and classification of production systems for bovine fattening in pastoral conditions in the semiarid Argentine Pampa called invernada, taking in account their physical, productive and economic characteristics and its management. A sampling of 56 farms was made at the Department of Quemú-Quemú, province of Pampa. Anova and cluster analysis were used to reduce the number of variables involved and to define groups of farmers. Three pastoral subsystems were identified; the first, denominated traditional grazing, responds to operations with low levels of productivity and daily average gain. In this system the 56 percent of surface were perennial pastures and the invernada lasteds for 23 months. This group of operations applies the criterion of minimum cost in the decision making. The second subsystem, denominated of transition marks the evolution between the traditional system and the technified one. The third subsystem is deno-minated technified grazing and shows greater levels of productivity and daily average gain; the farms use greater levels of feed and the 77 percent of the surface were pastures, and the invernada is finalized in 17 months. These operations apply the maximum benefits criterion in the decision making.El objetivo del estudio es la identificación y clasificación de los sistemas de pastoreo de engorde bovino invernada, en la Pampa Semiárida Argentina, según sus características físicas, productivas, económicas y de gestión. Se realizó un muestreo de 56 explotaciones en el Departamento de Quemú-Quemú, provincia de la Pampa. Mediante la aplicación de técnicas multivariantes se identifican tres subsistemas de pastoreo. El primero, denominado tradicional, responde a explotaciones con bajos niveles de productividad y ganancia media diaria, que utilizan bajos niveles de suplementación, destinando el 56 p.100 de la superficie ganadera a pasturas perennes y la invernada muestra una duración de 23 meses. Las explotaciones de este grupo aplican un criterio de mínimo coste en la toma de decisiones. El segundo subsistema, denominado de transición, marca la evolución entre el sistema tradicional y el tecnificado. El tercer subsistema se denomina pastoril tecnificado; con mayor productividad y ganancia media diaria, utiliza elevados niveles de suplementación y dedica un 77 p.100 de la superficie ganadera a las pasturas, reduciendo la invernada a 17 meses. Las explotaciones de este tipo aplican un criterio de máximo beneficio financiero en la toma de decisiones
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