81 research outputs found

    Field analysis of the deterioration after some years of use of four insect-proof screens utilized in Mediterranean greenhouses

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    The installation of insect-proof screens on greenhouse vents is one of the principal methods of protection against harmful insects for crops. Their main disadvantage lies on their negative effects on natural ventilation and greenhouse microclimate, which have been the focus of studies by several authors. However, few works have analysed the effect of accumulated dust and dirt on these screens. The present study has analysed four anti-insect screens, comparing their geometric characteristics before installation and after three to four years of use. Two negative effects have been observed and quantified: deterioration of the threads that make up the screen and reduction of porosity due to accumulated dirt in the pores. This deterioration over time gives leads to a mean increase in thread diameter of 3.1%, as well to a mean decrease in the pore size of 6.2% and 2.3% in the weft (Lpx) and the warp (Lpy), respectively. In fact, the insect-proof screen porosity (φ) decreased due to the deterioration of the threads by an average of 6.5%, in addition to an average 20.3% reduction due to the accumulation of dirt in the pores, making a total reduction in porosity of 26.8%. This decrease in porosity leads to lower greenhouse ventilation rates, and is therefore detrimental for the greenhouse microclimate. Consequently, it is recommended that insect-proof screens in arid areas such as Almería (Spain), with abundant dust suspended in the atmosphere, be washed monthly using water sprayed at high pressure

    Optimización superficial de alambres de ortodoncia de Ni-Ti superelástico mediante nitruración gaseosa. Parte II: Cuantificación de la mejora de la nanodureza y el coeficiente de fricción

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    La mejora del deslizamiento entre el alambre de ortodoncia y el bracket es uno de los principales problemas en la terapia ortodoncica. Este estudio presenta la nitruración gaseosa como un eficaz método de mejora del deslizamiento de los alambres ortodóncicos de Ni-Ti superelástico (composiciones cercanas a la equiatómica) respecto al bracket, principal inconveniente de estas aleaciones en la aplicación ortodóncica. Mediante microscopía óptica y electrónica de barrido se comprobó la existencia de una capa superficial nitrurada, así como la morfología de las fases presentes. Asimismo, se realizaron microanálisis químicos de las capas exteriores mediante técnica de energía dispersiva de rayos X. En todas las muestras nitruradas la dureza aumentó con la severidad del tratamiento y se alcanzaron valores de hasta 1111HV en comparación con los valores de 323 HV del alambre sin tratar. Se diseñaron ensayos de tipo pin on disk adaptados a las peculiaridades de los alambres, que mostraron un descenso del coeficiente de fricción. El endurecimiento y mejora de la fricción en la superficie del material se justifican por la formación de las capas nitruradas.Peer Reviewe

    Catalunya: difícil quedarse, difícil irse

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    Un texto colectivo que muestra la complejidad y las paradojas del caso Catalunya, un intento de independencia con muchas aristas y que, por sus alcances, trasciende al reino de España.ITESO, A.C

    Effect of Greenhouse Film Cover on the Development of Fungal Diseases on Tomato (Solanum lycopersicum L.) and Pepper (Capsicum annuum L.) in a Mediterranean Protected Crop

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    Greenhouses on the Mediterranean coast mainly use plastic materials as their cover. The influence of light exerted by these materials directly affects the crops by modifying the environment in which they develop. The aim of this study was to analyze the effect of the use of two plastic films in an experimental greenhouse on the development of fungal diseases in two spring–summer crop cycles: tomato (Solanum lycopersicum L.) from february to July 2021 and pepper (Capsicum annuum L.) from February to July 2022. The study was carried out in Almeria (Spain) in a multispan greenhouse divided transversely into two sectors by a polyethylene sheet. A commercial film was installed in the east sector (90% of transmissivity and 55% diffusivity) and an experimental film was installed in the west sector (85% of transmissivity and 60% diffusivity). In addition, the effect of the yield and quality of the harvested fruit was determined. In this study, two diseases were established naturally on the crop: (i) powdery mildew (Leveillula taurica) in both the tomato and the pepper crop cycles and (ii) early blight (Alternaria solani) in the tomato. The analyses of both diseases showed that the areas of the greenhouse that used the plastic cover, which presented a lower sunlight transmissivity, showed higher levels of disease than the areas that used the plastic cover that allowed greater transmissivity of light within the greenhouse, differing statistically in some phases of the crop. The marketable yield was 4.2% (for tomato) and 3.1% (for pepper) higher in the sector with the experimental film with high transmissivity. For both crops, the quality of the fruits did not show statistically significant difference

    Comparison between ROV video and Agassiz trawl methods for sampling deep water fauna of submarine canyons in the Northwestern Mediterranean Sea with observations on behavioural reactions of target species

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    In this paper we present a comparison between Remotely Operated Vehicle (ROV) and Agassiz trawling methods for sampling deep-water fauna in three submarine canyons of the Northwestern Mediterranean Sea and describe the behavioural reactions of fishes and crustacean decapods to ROV approach. 10 ROV dives, where 3583 individuals were observed and identified to species level, and 8 Agassiz trawls were carried out in a depth range of 750-1500 m. As noticed in previous studies, abundances of fishes and decapod crustaceans were much higher in the ROV videos than in Agassiz trawl samples, as the latter are designed for the retrieval of benthic, less motile species in permanent contact with the bottom. In our observations fish abundance was one order of magnitude higher with ROV (4110.22 ind/km2) than with Agassiz trawl (350.88 ind/km2), whereas decapod crustaceans were six times more abundant in ROV videos (6362.40 ind/km2) than in Agassiz samples (1364.52 ind/km2). The behaviour of highly motile fishes was analysed in terms of stationary positioning over the seafloor and avoidance or attraction to ROV approach. The most frequently occurring fish species Coelorinchus mediterraneus, Nezumia aequalis, Bathypterois dubius, Lepidion lepidion, Trachyrincuss scabrus and Polyacanthonotus rissoanus did not react to the presence of the ROV in most cases (>50%). Only B. dubius (11%), Lepidion lepidion (14.8%), P. rissoanus (41%) and T. scabrus (14.3%) reacted to ROV approach. More than 60% of less motile species, such as crustacean decapods, did not respond to ROV presence either. Only 33.3% of Geryon longipes, 36.2% of Munida spp. and 29.79% of Pagurus spp. were observed avoiding or defensively reacting to the ROV. The comparison of results obtained with ROV and trawl sampling is of ecological relevance since ROV can report observations in areas where trawling is technically unfeasible. The lack of reaction by most fish and crustacean decapod specimens further confirms that ROV surveying is an efficient technique to assess abundance and species composition in deep-sea waters for these motile species and questions trawl-based estimations

    The Role of Canyons in Strata Formation

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    This paper provides a spatial and temporal multi-scale approach of European submarine canyons. We fi rst present the long-term geologic view of European margins as related to controls on submarine canyon development. Then we discuss the extent to which submarine canyon systems resemble river systems because both essentially form drainage networks. Finally, we deal with the hortest-term, highestresolution scale to get a fl avor of the current functioning and health of modern submarine canyons in the northwestern Mediterranean Sea. Submarine canyons are unique features of the seafl oor whose existence was known by European fi shermen centuries ago, especially for those canyons that have their heads at short distance from shoreline. Popular names given to specifi c canyons in the different languages spoken in European coastal communities refer to the concepts of a"deep" or"trench." In the old times it was also common thinking that submarine canyons where so deep that nobody could measure their depth or even that they had no bottom. Submarine canyons are just one of the seven different types of seafl oor valleys identifi ed by Shepard (1973) in his pioneering morphogenetic classifi cation. Shepard (1973) defined submarine canyons as"steep-walled, sinuous valleys, with V-shaped cross sections, and relief comparable even to the largest of land canyons; tributaries are found in most of the canyons and rock outcrops abound on their walls." Canyons are features typical of continental slopes with their upper reaches and heads cut into the continental shelf

    Anxiety, Distress and Stress among Patients with Diabetes during COVID-19 Pandemic: A Systematic Review and Meta-Analysis

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    The prevalence of mental health disorders has increased during the COVID-19 pandemic. Patients with chronic diseases, such as diabetes, are a particularly vulnerable risk group. This study aims to assess the levels and prevalence of anxiety, distress, and stress in patients with diabetes during the COVID-19 pandemic. A systematic review was conducted in CINAHL, Cochrane, LILACS, Medline, SciELO, and Scopus in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Thirty-seven articles with a total of 13,932 diabetic patients were included. Five meta-analyses were performed. The prevalence of anxiety was 23% (95% CI = 19–28) in T1DM and 20% (95% CI = 6–40) in T2DM patients. For diabetes distress it was 41% (95% CI = 24–60) for T1DM and 36% in T2DM patients (95% CI = 2–84). For stress, the prevalence was 79% (95% CI = 49–98) in T1DM patients. People with diabetes have significant psychiatric comorbidity as well as psychological factors that negatively affect disease management, increasing their vulnerability in an emergency situation. To establish comprehensive care in diabetic patients addressing mental health is essential, as well as including specific policy interventions to reduce the potential psychological harm of the COVID-19 pandemic

    Continuity of Nursing Care in Patients with Coronary Artery Disease: A Systematic Review

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    Coronary artery disease is the leading cause of death worldwide and patient continuity of care is essential. Health professionals can help in the transition stage by providing resources to achieve pharmacological treatment adherence, as well as social and emotional support. The objective was to analyse the effects of nursing interventions based on continuity of care in patients with coronary artery disease after hospital discharge. A systematic review of randomised controlled trials and quasi-experimental studies was carried out. Cochrane, CINAHL, Health & medical collection, Medline, and Scopus databases were consulted in January 2022. PRISMA guidelines were followed with no time limits. In total, 16 articles were included with a total of 2950 patients. Nurse-led continuity of care programs improved the monitoring and control of the disease. Positive effects were found in the quality of life of patients, and in mental health, self-efficacy, and self-care capacity dimensions. Clinical parameters such as blood pressure and lipid levels decreased. The continuity of care provided by nurses had a positive influence on the quality of life of patients with coronary artery disease. Nurse-led care focused on the needs and resources, including continuity of care, plays a key role
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