127 research outputs found

    Agricultural productivity in the European Union convergence or divergence among members?

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    Sound increases in agricultural productivity and incomes have been from the very begining two of the main goals of the Common Agricultural Policy of the European Economic Community (now European Union - EU). The paper tries to evaluate, through the estimation of convergence coefficients, if the increments achieved have widened or closed the gap between EU member states. Results indicate that the richest countries either maintain their positive differences to the Union's average (Netherlands and Belgium) or even enlarge it (Denmark). France shows a quick convergence pattern, while countries where Mediterranean production exceeds 30 % of Total Agricultural Output either keep their negative gap (Italy), or even enlarge it (Greece) or slowly converge to the average (Spain). Portugal does converge but still has a long way to reach its European partners. For the remaining countries no significant convergence coefficients were found.

    The Common Agricultural Policy and the greenhouse gases emissions.

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    The evolution of greenhouse gases emissions in the EU-15 countries is accessed. While the absolute level of emissions turns out to be declining in the last thirty years in EU-15 Member States, emissions per output tend to rise. A relationship between the adoption of the Common Agricultural policy and the emissions level can be detected for Spain, Austria, Finland and Sweden.

    Exact and Heuristic Algorithms for Energy-Efficient Scheduling

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    The combined increase of energy demand and environmental pollution at a global scale is entailing a rethinking of the production models in sustainable terms. As a consequence, energy suppliers are starting to adopt strategies that flatten demand peaks in power plants by means of pricing policies that stimulate a change in the consumption practices of customers. A representative example is the Time-of-Use (TOU)-based tariffs policy, which encourages electricity usage at off-peak hours by means of low prices, while penalizing peak hours with higher prices. To avoid a sharp increment of the energy supply costs, manufacturing industry must carefully reschedule the production process, by shifting it towards less expensive periods. The TOU-based tariffs policy induces an implicit partitioning of the time horizon of the production into a set of time slots, each associated with a non-negative cost that becomes a part of the optimization objective. This thesis focuses on a representative bi-objective energy-efficient job scheduling problem on parallel identical machines under TOU-based tariffs by delving into the description of its inherent properties, mathematical formulations, and solution approaches. Specifically, the thesis starts by reviewing the flourishing literature on the subject, and providing a useful framework for theoreticians and practitioners. Subsequently, it describes the considered problem and investigates its theoretical properties. In the same chapter, it presents a first mathematical model for the problem, as well as a possible reformulation that exploits the structure of the solution space so as to achieve a considerable increase in compactness. Afterwards, the thesis introduces a sophisticated heuristic scheme to tackle the inherent hardness of the problem, and an exact algorithm that exploits the mathematical models. Then, it shows the computational efficiency of the presented solution approaches on a wide test benchmark. Finally, it presents a perspective on future research directions for the class of energy-efficient scheduling problems under TOU-based tariffs as a whole

    Correction to: Deep reinforcement learning for multi-objective placement of virtual machines in cloud datacenters

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    Page 2: Column 2, lines 2-4, previously read: "Specifically, we consider a decision maker that, after a proper training, is able to select the most suitable heuristic for compute the placement for each VM requested by end users"

    Enanismo y podredumbre basal de Eustoma grandiflorum y su relación con la densidad de Fusarium solani en el suelo

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    En cultivos comerciales de lisianthus de La Plata y alrededores (Argentina), se observó que Fusarium solani afecta al 100% de los establecimientos productivos provocando enanismo y podredumbre basal. Se realizó un ensayo para analizar la densidad de F. solani del suelo bajo el efecto de distintos tratamientos y relacionarla con la evolución de ambas patologías. Los análisis del suelo se hicieron en 3 épocas: antes del transplante (octubre), al inicio (enero) y al final (marzo) de la floración. En enero y marzo se evaluó la incidencia de cada enfermedad y se cuantificaron las plantas cosechadas. La población de F. solani no varió en las 3 épocas y se redujo significativamente con los fumigantes y el vapor. Esto determinó una incidencia del enanismo (enero) de 0 a 9,5% con los primeros y de 31,4% con el vapor. Para el testigo y los fungicidas la incidencia varió entre el 87,9 y el 100%, disminuyendo las plantas cosechadas. La podredumbre basal comenzó con el ingreso del patógeno a través de las heridas producidas por la cosecha. Ésta fue significativamente mayor con los fumigantes (90,7 a 99%) y también con el vapor (76,8%), produciéndose la mayor incidencia en marzo (15,7 a 22,2 y 10,1% respectivamente), reduciéndose el período productivo. Se destaca la importancia de disminuir la densidad de F. solani en el momento del transplante. Entre los métodos de control el Metam sodio y Dazomet podrían ser eficaces sustitutos del Bromuro de metilo, seguidos por el vapor.Fusarium solani was recorded in 100% of the commercial crops of lisianthus (Eustoma grandiflorum) located around La Plata (Argentina). The pathogen causes stunt and basal rot. A trial was carried out to analyse the F. solani soil density and its relation to the development of both diseases. Soil samples were analysed at three times: before transplant (October), at the beginning of flowering (January) and at the ending of flowering (March) of flowering. The incidence of each disease was evaluated in January and March, and the plants harvested were quantified. The soil density of F. solani was not altered during the three times for each treatment, and fumigants and steam decrease it significantly. In January the stunt incidence reached 0 to 9.5% with the fumigants and 31.4% with the steam treatment. In the control and fungicide plots, the incidence reached 87.9 to 100%, and a consequent reduction of flower production was observed. Stem rot began after the flowers were harvested as a result of pathogen entry through the wounds. The major values of harvested plants were obtained with fumigants (90.7 to 99%) and steam (76.8%), so the greatest stem rot incidence was 15.7 to 22.2 and 10.1%, respectively, in March, and the productive period was shortened. The need of reducing F. solani soil density before lisianthus transplant is emphasized. Among soil control treatments, Metham sodium and Dazomet could be effective substitutes for Methil bromide followed by steam treatment

    Surgical Repair of Postinfarction Ventricular Septal Rupture: Systematic Review and Meta-Analysis.

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    Background. Ventricular septal rupture (VSR) is a rare but life-threatening complication after acute myocardial infarction. Although surgical correction is challenging and associated with high mortality, it remains the treatment of choice. This systematic review and meta-analysis aimed to evaluate the early outcome of surgical VSR repair.Methods. We searched electronic databases from January 1998 to February 2020. Studies reporting patients undergoing surgical treatment for VSR were analyzed. The primary outcome assessed was operative mortality. Differences were expressed as odds ratios (ORs) with 95% confidence intervals (CIs) to assess the relationships of predefined surgical variables and clinical prognosis.Results. A total of 6361 adult patients from 41 studies were identified. Operative mortality was 38.2%. Pooled ORs showed increased odds of operative mortality in patients with preoperative or perioperative intraaortic balloon pump insertion (OR = 3.48; 95% CI, 3.01-4.02; P >= .001), right ventricular dysfunction (OR = 2.85; 95% CI, 1.47-5.52; P = .002), posterior VSR (OR = 1.73; 95% CI, 1.30-2.31; P >= .001), and emergency surgery (OR = 3.79; 95% CI, 2.52-5.72; P >= .001). Temporal trend evaluation revealed no difference over time in the operative mortality rate; it was 34% in both time-related groups (1971-2000 versus 2001-2018).Conclusions. Ventricular septal rupture repair has a high operative mortality. Patients with preoperative or perioperative intraaortic balloon pump support, right ventricular dysfunction at presentation, or posterior defects, and those undergoing emergent VSR correction have increased odds of operative mortality. (C) 2021 by The Society of Thoracic Surgeons. Published by Elsevier Inc
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