Tipología de las zonas regables de la demarcación hidrográfica del Guadalquivir

La agricultura de regadío en la Demarcación Hidrográfica del Guadalquivir (DHG) ha sufrido un importante proceso de cambio en las últimas dos décadas, caracterizado fundamentalmente por la irrupción del olivar y la modernización de las zonas regables. Ello ha resultado en un aumento de la superficie regada, que prácticamente se ha doblado hasta sobrepasar ampliamente las 800.000 ha, y en el consecuente incremento de la demanda de agua. Estos cambios, entre otros, no han hecho sino enriquecer la variedad de sistemas agrarios de regadío que conviven en la DHG y que pueden presentar características diferenciales. Este contexto de cambio justifica la necesidad de actualizar el conocimiento de estos sistemas. En consecuencia, en el presente trabajo se propone una tipología de las zonas regables de la DHG. Para ello se ha utilizado el Inventario de Regadíos de 2008, empleándose como unidad básica de agrupación las unidades de agregación de recintos (UAs), que componen dicho inventario, y como variables de agrupación, las variables estructurales y de distribución de cultivos de estas unidades. De esta forma, se ha obtenido una tipología que muestra cinco grupos internamente homogéneos y diferentes entre sí, y que capta a su vez la esencia del proceso de cambio mencionado. Por consiguiente, esta tipología se revela como una herramienta útil para su empleo en análisis dirigidos al apoyo de toma de decisiones, básicamente relativas a políticas públicas (tanto hidrológica como agraria), encaminados hacia una mejor gobernanza del regadío en la DHG

The design of agri-environmental schemes: Farmers’ preferences in southern Spain

Paper accepted to be published in Land Use Policy (ISSN: 0264-8377)Agri-environmental schemes (AES) play a key role in promoting the production of environmental public goods by European Union agriculture. Although extensive literature has analyzed AES, some important issues remain understudied. This paper performs an ex-ante assessment of AES in permanent cropping, analyzing several issues that have received little attention from researchers, such as ecological focus areas (EFA) and collective participation. For this purpose, a choice experiment was used to assess farmers’ preferences toward AES in a case study of olive groves in southern Spain. Results show high heterogeneity among farmers, with different classes being identified, from potential participants to non-participants. As regards EFA, almost half of the farmers would be willing to accept it for low monetary incentives (€8-9/ha per additional 1% of the farmland devoted to EFA) while the rest would do it for moderate-to-high monetary incentives (€41-151/ha per additional 1% of EFA). However, for a high share of EFA (e.g., 5-7%) higher incentives would presumably be required due to the intrinsic spatial restrictions of olive groves. With regard to collective participation, we find that it is unlikely that farmers would participate collectively with the incentive of the up-to-30% EU-wide bonus. These results are relevant for policy-making now when new AES are being designed for the next programming period 2014-2020.This research is co-financed by the Spanish Ministry of Economics and Competitiveness (MINECO) and the European Regional Development Fund (ERDF) through the project MERCAGUA (AGL2013-48080-C2-1-R)

Unraveling determinants of inferred and stated attribute non-attendance: effects on farmers’ willingness to accept to join agri-environmental schemes

Attribute non-attendance (ANA) has received very little attention in the context of willingness to accept (WTA), although an increasing number of studies analyze the preferences of ecosystem service providers towards incentive-based schemes. We add to the understanding of ANA behavior by analyzing stated and inferred ANA in a choice experiment investigating farmers’ WTA for participating in agri-environmental schemes (AES) in southern Spain. We use mixed logit models, following Hess and Hensher (2010) for the inferred ANA approach. Evidence is found of ANA behavior for both stated and inferred approaches, with models accounting for ANA clearly outperforming those that do not account for it; however, we produce no conclusive results as to which ANA approach is best. WTA estimates are only moderately affected, which to some extent is consistent with the low level of non-attendance found for the monetary attribute. Stated and inferred approaches show very similar WTA estimates. Additionally, we investigate sources of observed heterogeneity related to ANA behavior by using a sequence of bivariate probit models for each attribute. Overall, our results hint at a positive relationship between ease of scheme adoption and non-attendance to attributes. However, further research is still needed in this field

Evaluating the soft error sensitivity of a GPU-based SoC for matrixmultiplication

System-on-Chip (SoC) devices can be composed of low-power multicore processors combined with a small graphics accelerator (or GPU) which offers a trade-off between computational capacity and low-power consumption. In this work we use the LLFI-GPU fault injection tool on one of these devices to compare the sensitivity to soft errors of two different CUDA versions of matrix multiplication benchmark. Specifically, we perform fault injection campaigns on a Jetson TK1 development kit, a board equipped with a SoC including an NVIDIA ”Kepler“ Graphics Processing Unit (GPU). We evaluate the effect of modifying the size of the problem and also the thread-block size on the behaviour of the algorithms. Our results show that the block version of the matrix multiplication benchmark that leverages the shared memory of the GPU is not only faster than the element-wise version, but it is also much more resilient to soft errors. We also use the cuda-gdb debugger to analyze the main causes of the crashes in the code due to soft errors. Our experiments show that most of the errors are due to accesses to invalid positions of the different memories of the GPU, which causes that the block version suffers a higher percentage of this kind of errors

Bimineralic calcite-aragonite rafts in the hypogeous lakes of Cova dets Ases (Mallorca): controls on precipitation and polymorphism.

[eng] Calcite-aragonite bimineralic rafts and related waters from hypogenic lakes in the coastal cave of “Cova dets Ases”, Mallorca, have been analyzed for mineralogy and geochemistry (including stable isotopes). The main objective has been the evaluation of the factors that control the chemical and mineralogical composition of the precipitates as they are another natural example of the classical problem of aragonite vs calcite precipitation. The hydrochemistry of the lakes in these coastal caves is mainly conditioned by the mixture of fresh and marine waters. The percentage of mixing, together with the CO2 degasification from the lakes water, seems to play a fundamental role in the precipitation of the carbonate rafts. However, their presence in the studied lakes does not show a homogeneous distribution in space and time and no clear relation has been found between that distribution and the evolution of any of the monitored environmental variables. With respect to their mineralogy, the main factor that seems to control the dominant bimineralic composition of the rafts studied here is the Mg/Ca ratio in the waters, which means the percentage of marine component in those waters. The variations of this ratio, in combination with changes in the degasification rate and in the oversaturation with respect to calcite and aragonite will condition the presence of one or the other polymorph. Even small microenvironmental variations seem to affect the order of precipitation of these bimineralic rafts. Another important issue in this work is that the data obtained in this natural system have been used to check the most suitable δ18O isotope fractionation equations for the paleotemperature calculations from rafts precip- itated in the past under similar conditions

Comparative analysis of soft-error sensitivity in LU decomposition algorithms on diverse GPUs

Graphics processing units (GPUs) have become integral to embedded systems and supercomputing centres due to their large memory, cutting-edge technology and high performance per watt. However, their susceptibility to transient errors requires a comprehensive analysis of error sensitivity, as well as the development of error mitigation techniques and fault-tolerant algorithms. This study focuses on evaluating the soft-error sensitivity of two distinct versions of LU decomposition algorithms implemented on two very diferent GPUs—a low-power SoC embedded GPU and a high-performance massively parallel GPU. Through extensive fault injection campaigns on both GPUs, we examine the vulnerability of the algorithms, identify error causes, and determine critical code components requiring enhanced protection. The experiments reveal that most single bit fip fault injections in the instruction results lead to erroneous outcomes or unrecoverable errors. Notably, efcient GPU resource utilisation can increase the number of masked errors, thereby enhancing error resilience. Additionally, while diferent parts of the code exhibit similar error occurrence types and rates, the propagation of errors to elements within the result matrix difers signifcantlyFunding for open access charge: CRUE-Universitat Jaume

Spatial analysis of demand for sparsely-located ecosystem services using alternative index approaches

This study is focused on the effects of spatial discounting and substitute sites on the demand for ecosystem services (ES) provided by scattered agroecosystems. New ways of modelling these two effects are proposed, relying on area-based and density-based indexes. Data from discrete choice experiments are used, based on a case study of Andalusian olive groves (southern Spain). The results show that model fit is significantly improved by the introduction of these spatial indexes, with the best outcome found for the area-based index combined with the inverse of the distance. Results provide evidence of substantial spatial heterogeneity depending on the ES (carbon sequestration, soil conservation and biodiversity), indicating different economic jurisdiction

Analysing the influence of memory and workload on the reliability of GPUs under neutron radiation

Evaluating the impact of utilising different GPU resources is crucial for gaining insights into the reliability of GPUs when exposed to radiation. In this study, we employed various versions of a microbenchmark to investigate the effect of different memory types on the performance of a low-power GPU integrated into the TX1 SoC of a Jetson Nano board. Additionally, we explored the trade-off between enhanced computational performance and the occurrence of failures over time by optimising the utilisation of GPU resources. Our findings demonstrate that maximising the utilisation of the device’s cores enables the completion of a greater number of computations without errors. By fully harnessing the computational potential of the GPU cores, we effectively increase the work that we can complete between failures. Moreover, we observed that the use of the different memory types has a significant influence on the overall reliability of the GPU. The outcomes of this research contribute to a comprehensive understanding of the interplay between GPU resources, irradiation effects, and reliability. This knowledge is instrumental in guiding the development of robust GPUs for applications in radiation-prone environments.Funding for open access charge: CRUE-Universitat Jaume

Pharmacophore-Based Virtual Screening to Discover New Active Compounds for Human Choline Kinase a1

Choline kinase (CK) catalyses the transfer of the ATP gamma-phosphate to choline to generate phosphocholine and ADP in the presence of magnesium leading to the synthesis of phosphatidylcholine. Of the three isoforms of CK described in humans, only the a isoforms (HsCK alpha) are strongly associated with cancer and have been validated as drug targets to treat this disease. Over the years, a large number of Hemicholinium-3 (HC-3)-based HsCK alpha biscationic inhibitors have been developed though the relevant common features important for the biological function have not been defined. Here, selecting a large number of previous HC-3-based inhibitors, we discover through computational studies a pharmacophore model formed by five moieties that are included in the 1-benzyl-4-(N-methylaniline) pyridinium fragment. Using a pharmacophore-guided virtual screening, we then identified 6 molecules that showed binding affinities in the low mM range to HsCK alpha 1. Finally, protein crystallization studies suggested that one of these molecules is bound to the choline and ATP-binding sites. In conclusion, we have developed a pharmacophore model that not only allowed us to dissect the structural important features of the previous HC-3 derivatives, but also enabled the identification of novel chemical tools with good ligand efficiencies to investigate the biological functions of HsCK alpha 1