Technical efficiency of sea bass and sea bream farming in the Mediterranean Sea by European firms: A stochastic production frontier (SPF) approach

In recent years, European producers of cultured sea bass and sea bream have experienced a highly competitive market with low prices that have caused profitability challenges. An important factor of economic competitiveness for firms is to produce efficiently. In this paper, technical efficiency of European producers of cultured sea bass and sea bream is evaluated for the period 2008-2017 using the stochastic production frontier (SPF) approach. In addition, the effect of a set of specific-firm factors on firms' efficiency is investigated. The majority of firms in the sample were found to have a technical efficiency over 90% with Cypriot and Greek firms being, on average, the most efficient. We also found evidence that the technical efficiency of these firms is positively related to their size. Moreover, the high degree of average efficiency means that further production growth requires innovations that move up the production frontier

Analyse de la consommation de bar et de daurade dans les pays méditerranéens de l' Union.

ABSTRACT. The overall objective of this study is to analyse the situation of the seabream and seabass market, in order to provide relevant information for designing sustainable development strategies. It is divided into two parts: the first is an aggregated study about the factors affecting consumption in the Mediterranean countries of the European Union, which concentrated 79.5% of the consumption of these species in 2005. The second part is more specific and studies the influence that awareness and attitude towards aquaculture has on consumption patterns and valuation of the species, factors that are to be taken into account when designing specific strategies for each market. This latter part is confined to the Spanish market, and therefore results cannot be extrapolated to others, but they may serve as reference given that Spain accounts for 18.6% of total seabream and seabass consumption in the European Union.RÉSUMÉ. L' objectif global de cette étude est d' analyser la situation du marché du bar et de la daurade, afin de fournir une information utile pour la mise au point de stratégies de développement durable. Elle est divisée en deux parties : la première est constituée par une étude agrégée sur les facteurs qui influencent la consommation dans les pays méditerranéens de l Union Européenne, qui ont concentré 79,5% de la consommation de ces espèces en 2005. La seconde partie est plus spécifique et examine l' influence que la sensibilisation et l' attitude vis-à-vis de l 'aquaculture présentent sur les tendances de connsommation et d 'appréciation de ces espèces, facteurs qui entrent en ligne de compte pour la conception de stratégies spécifiques à chaque marché. Cette dernière partie se limite au marché espagnol, et par conséquent les résultats ne peuvent pas être extrapolés à d 'autres marchés, mais ils peuvent toutefois servir de référence étant donné que l' Espagne représente 18,6% de la consommation totale de bar et de daurade au sein de l' Union Européenne

A HLLC scheme for Ripa model

We consider the one-dimensional system of shallow-water equations with horizontal temperature gradients (the Ripa system). We derive a HLLC scheme for Ripa system which falls into the theory of path-conservative approximate Riemann solvers. The resulting scheme is robust, easy to implement, well-balanced, positivity preserving and entropy dissipative for the case of flat or continuous bottom

Less invasive beractant administration in preterm infants: a pilot study

OBJECTIVES: The aims of this study were to assess the efficacy and feasibility of a new, less invasive surfactant administration technique for beractant replacement using a specifically designed cannula in preterm infants born a

Initial respiratory management in preterm infants and bronchopulmonary dysplasia

BACKGROUND: Ventilator injury has been implicated in the pathogenesis of bronchopulmonary dysplasia. Avoiding invasive ventilation could reduce lung injury, and early respiratory management may affect pulmonary outcomes. OBJECTIVE: To analyze the effect of initial respiratory support on survival without bronchopulmonary dysplasia at a gestational age of 36 weeks. DESIGN/METHODS: A prospective 3-year observational study. Preterm infants of <32 weeks gestational age were classified into 4 groups according to the support needed during the first 2 hours of life: room air, nasal continuous positive airway pressure, intubation/surfactant/extubation and prolonged mechanical ventilation (defined as needing mechanical ventilation for more than 2 hours). RESULTS: Of the 329 eligible patients, a total of 49% did not need intubation, and 68.4% did not require prolonged mechanical ventilation. At a gestational age of 26 weeks, there was a significant correlation between survival without bronchopulmonary dysplasia and initial respiratory support. Preterm infants requiring mechanical ventilation showed a higher risk of death and bronchopulmonary dysplasia. After controlling for gestational age, antenatal corticosteroid use, maternal preeclampsia and chorioamnionitis, the survival rate without bronchopulmonary dysplasia remained significantly lower in the mechanically ventilated group. CONCLUSIONS: In our population, the need for more than 2 hours of mechanical ventilation predicted the development of bronchopulmonary dysplasia in preterm infants with a gestational age >26 weeks (sensitivity =89.5% and specificity = 67%). The need for prolonged mechanical ventilation could be an early marker for the development of bronchopulmonary dysplasia. This finding could help identify a target population with a high risk of chronic lung disease. Future research is needed to determine other strategies to prevent bronchopulmonary dysplasia in this high-risk group of patients

Water-soluble fluorosilane supplemented with fumed silica as admixture for producing hydrophobic concrete: Effects on cement hydration, mechanical properties and water protection properties

Hydrophobic admixtures protect concrete from water-related degradation, although they may have negative effects over cement hydration, mechanical properties and have low miscibility with water. Aiming to overcome these drawbacks, this work studies the properties of concretes containing admixtures based on a water-soluble fluoroalkylsilane and fumed silica to densify the structure. The effects of the admixture were evaluated in terms of hydrophobic, mechanical and chemical properties. The admixture decreased capillary absorption by over 70% while also increasing the internal cohesion, despite an increased porosity. Raman and XRD analysis indicated it promoted the consumption of C3S and the formation of portlandite and C–S–H gels with higher silicon content, compensating the effect of porosity on the concrete resistance. Incorporation of fumed silica in the admixture delayed the early development of hydrated phases, but after full curing promoted a more compact structure of the cement matrix, decreasing water absorption rate and improving mechanical properties

Influence of gold nanoparticles size for photocatalytic NO oxidation in low loading Au/TiO2 catalysts

Gold nanoparticles (AuNPs) supported on TiO2 are one of the most investigated photocat-alysts, however, the positive effect of AuNPs size reduction on Au/TiO2 activity is clear for conventional catalysis, but this relationship not strictly happens in photocatalysis. The present work investigates how small changes in the lower size range of AuNPs can affect the Au/TiO2 photoactivity in order to maximize the performance of photocatalysts with low metal loadings (<1 wt%). Precipitation-deposition methods and a speciation-controlled incipient wetness impregnation (ScIWI) method have been employed for preparing Au/TiO2 photocatalysts that exhibited a NOx elimination capacity significantly higher than pristine TiO2. Comparing the photocatalysts, ScIWI method achieved the highest gold dispersion and Au-TiO2 contact perimeter providing the most active photocatalysts, confirming the positive effect of AuNPs size reduction in the average sizes around 2 nm. In addition, on the basis of the results obtained, it has been proposed that the adsorption of nitrogen oxides species on gold has a relevant role on the NO photooxidation process.(c) 2023 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Propuesta de un modelo de producción basado en herramientas Lean soportado por una gestión del cambio para mejorar la productividad del sector agricultor de zapallo en Ocucaje, Ica

El presente trabajo de investigación está enfocado en analizar y establecer lineamientos técnicos de algunas herramientas de la manufactura esbelta como la estandarización de operaciones, gestión visual y KPIs (Indicadores claves de desempeño), que se ajustarían al contexto del sector agrícola y resultarían prácticos de aplicar por parte de los agricultores, con el objetivo de incrementar la productividad del sector agroalimentario de zapallos de Ocucaje en Ica, Perú. Para ello, la aplicación de los lineamientos de las herramientas lean estará soportado por una gestión del cambio para que los agricultores presenten una menor resistencia a los cambios propuestos y presenten un mejor compromiso con el proyecto. En ese sentido, la investigación presenta un marco que desarrolla un estudio de las perspectivas estratégicas y operativas sobre la adaptabilidades de las herramientas en un sector diferente para el cual fueron creadas las herramientas del Sistema de Producción Toyota. A pesar que existe una limitada cantidad de información sobre la adaptabilidad y aplicación de las herramientas lean en el sector agrícola y en especial si es en el Perú.This research work is focused on the analysis of the best lean tools that can increase the productivity of the agri-food sector of pumpkins from Ocucaje in Ica, Peru; In other words, the research is aimed at analyzing and establishing of the best lean tools that it adjust to the context of the pumpkins producing sector in Ocucaje that can increase production productivity and can be used by farmers and achieve operational standards of quality. To do this, the application of the tools will be supported by change management so that farmers present less resistance to the proposed changes and present a better commitment to the project. In this sense, the research presents a framework that develops a study of the strategic and operational perspectives on the adaptability of lean tools in a different sector for which the Toyota Production System tools were created. Although there is a limited amount of information on the adaptability and application of lean tools in the agricultural sector and especially if it is in Peru.Tesi

High-Frequency Oscillatory Ventilation Combined with Volume Guarantee in a Neonatal Animal Model of Respiratory Distress Syndrome

Objective. To assess volume guarantee (VG) ventilation combined with high-frequency oscillatory ventilation (HFOV) strategy on PaCO(2) regulation in an experimental model of neonatal distress syndrome. Methods. Six 2-day-old piglets weighing 2.57 ± 0.26 kg were used for this interventional experimental study. Animals were ventilated during physiologic lung conditions and after depletion of lung surfactant by bronchoalveolar lavage (BAL). The effect of HFOV combined with VG on PaCO(2) was evaluated at different high-frequency expired tidal volume (VThf) at constant frequency (f (R)) and mean airway pressure (mPaw). Fluctuations of the pressure (ΔPhf) around the mPaw and PaCO(2) were analyzed before and after lung surfactant depletion. Results. PaCO(2) levels were inversely proportional to VThf. In the physiological lung condition, an increase in VThf caused a significant decrease in PaCO(2) and an increase in ΔPhf. After BAL, PaCO(2) did not change as compared with pre-BAL situation as the VThf remained constant by the ventilator. Conclusions. In this animal model, using HFOV combined with VG, changes in the VThf settings induced significant modifications in PaCO(2). After changing the lung condition by depletion of surfactant, PaCO(2) remained unchanged, as the VThf setting was maintained constant by modifications in the ΔPhf done by the ventilator

Studying the bulk hydrophobization of cement mortars by the combination of alkylalkoxysilane admixture and fluoropolymer-functionalized aggregate

In this work, hydrophobic mortars are produced by combining a silane-based admixture with the pre-treatment of the aggregates with an alkoxysilane-ended fluoropolymer. A comparative study is presented to determine the effect of the components, under different curing conditions, on the hydrophobicity, mechanical performance, composition and micro-structure. The combination of both strategies allows obtaining hydrophobic properties at different curing conditions, whereas the silane loses effectiveness at high humidity and the modified aggregate at low humidity. The silane hinders cement hydration and promotes gaps in the aggregate-matrix interfacial transition zone, decreasing mechanical resistance, whereas the modified aggregate changes the interfacial transition zone morphology without significant effects on resistance. The combination of both strategies partially compensates the negative impact of the silane admixture, especially when the mortars are cured at high humidity. Thus, this combination increases versatility of the mortars and poses as a potential route to address the limitations of silane admixtures. © 2022 The Author