Comportamiento mecánico de la aleación W+1%Y2O3 en función de la atmósfera y la temperatura

Mediante ensayos de flexión en tres puntos se compara y evalúa el comportamiento mecánico de la aleación W- 1wt%Y2O3 con el W puro fabricados ambos mediante HIP. Se ha obtenido la tenacidad de fractura, la resistencia a flexión y el límite elástico en atmósfera oxidante y de vacío en un intervalo de temperaturas comprendido entre -196 ºC, ensayos de inmersión en nitrógeno líquido, y 1200 ºC. Previamente, se ha medido la densidad, la dureza mediante ensayos Vickers y el módulo de elasticidad dinámico de los materiales. Además, la dureza y el módulo de elasticidad se han comparado con los obtenidos mediante ensayos instrumentados de nanoindentación. Finalmente se ha realizado un pequeño estudio de las superficies de fractura de las muestras ensayadas mediante microscopía electrónica de barrido para poder relacionar el modo de rotura de los materiales y las propiedades mecánicas macroscópicas con los micromecanismos de fallo involucrados en función de la temperatura

Mechanical characterisation of tungsten-1wt.% yttrium oxide as a function of temperature and atmosphere

This study evaluates the mechanical behaviour of an Y2O3-dispersed tungsten (W) alloy and compares it to a pure W reference material. Both materials were processed via mechanical alloying (MA) and subsequent hot isostatic pressing (HIP). We performed non-standard three-point bending (TPB) tests in both an oxidising atmosphere and vacuum across a temperature range from 77 K, obtained via immersion in liquid nitrogen, to 1473 K to determine the mechanical strength, yield strength and fracture toughness. This research aims to evaluate how the mechanical behaviour of the alloy is affected by oxides formed within the material at high temperatures, primarily from 873 K, when the materials undergo a massive thermal degradation. The results indicate that the alloy is brittle to a high temperature (1473 K) under both atmospheres and that the mechanical properties degrade significantly above 873 K. We also used Vickers microhardness tests and the dynamic modulus by impulse excitation technique (IET) to determine the elastic modulus at room temperature. Moreover, we performed nanoindentation tests to determine the effect of size on the hardness and elastic modulus; however, no significant differences were found. Additionally, we calculated the relative density of the samples to assess the porosity of the alloy. Finally, we analysed the microstructure and fracture surfaces of the tested materials via field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). In this way, the relationship between the macroscopic mechanical properties and micromechanisms of failure could be determined based on the temperature and oxides forme

On the ubiquity of trivial torsion on elliptic curves

The purpose of this paper is to give a "down--to--earth" proof of the well--known fact that a randomly chosen elliptic curve over the rationals is most likely to have trivial torsion

Hábitos de sueño y problemas relacionados con el sueño en adolescentes: relación con el rendimiento escolar

ObjetivoConocer la prevalencia de trastornos de sueño en los adolescentes. Describir los hábitos de sueño de los adolescentes y su relación con los trastornos del sueño y los factores asociados. Conocer la relación entre los trastornos del sueño y/o los hábitos de sueño inadecuados con el rendimiento escolar.DiseñoEstudio observacional, descriptivo y transversal.EmplazamientoInstitutos de enseñanza secundaria obligatoria (ESO) de la ciudad de Cuenca.ParticipantesUn total de 1.293 alumnos escolarizados en primero y cuarto cursos de ESO.Mediciones principalesHábitos de sueño en días lectivos y fines de semana y prevalencia de trastornos del sueño medidos mediante un cuestionario estructurado con preguntas abiertas y cerradas, autoadministrado y anónimo. Se determinó el rendimiento escolar de los alumnos y su relación con los hábitos y trastornos de sueño.ResultadosDe los 1.293 alumnos matriculados, completaron la encuesta 1.155 (89,33%), 537 (45,9%) chicos y 618 (54,1%) chicas, con una media de edad de 14 años (rango, 11-18 años). Los días laborables se acuestan en promedio a las 23.17 y se levantan a las 7.46 (tiempo medio, 8 h y 18 min) y los fines de semana se acuestan a la 1.02 y se levantan a las 10.42 (tiempo medio, 9 h y 40 min). El 45,4% declara dormir mal la noche del domingo al lunes. El promedio de asignaturas suspendidas es mayor en los adolescentes con queja de sueño (2,28 frente a 1,91; p = 0,04), los que se levantan cansados (2,17 frente a 1,97; p = 0,048) y los que tienen somnolencia diurnal (2,17 frente a 1,75; p = 0,004).ConclusionesEl horario escolar conlleva deuda de sueño durante la semana que se recupera parcialmente el fin de semana. En los fines de semana se produce una rotura en los hábitos de sueño de los adolescentes. Los adolescentes con problemas relacionados con el sueño muestran peor rendimiento escolar.ObjectiveTo determine the prevalence of sleep disorders in adolescence.To describe sleeping habits of adolescents in relation to sleep disorders and associated factors. To determine the relation between sleep disorders/inappropiate sleeping habits and school performance.DesignObservational, descriptive, crosssectional study.SettingSecondary school of Cuenca (city in Spain).Participants1293 school children of first and fourth curses of secondary education.Main measuresStructured questionnaire with opened and closed questions on sleeping habits during weekdays and at weekends and sleep disorders to be answered by the adolescents anonymously and on their own. Student's school performance with relation with to sleeping habits and sleep disorders were determined.Results1155 students out of 1293 (response rate 89.33%) answered the questionnaire, 537 (45.9%) boys and 618 (54.1%) girls, 14 years old on average (between 11-18 years). On weekdays students went to bed at 23.17 h and got up at 7.46 h (average sleeping time =8 hours and 18 minutes). At weekends they went to bed at 1.02 h and got up at 10.42 h (average sleeping time =9 hours and 40 minutes). 45.4% of students said to sleep badly on Sunday night's.On average the number of subjects failed in class is higher with adolescents who complain about sleep (2.28 vs 1.91; P=.04), who are tired at waking up time (2.17 vs 1.97; P=.048) and who have morning sleepiness (2.17 vs 1.75; P=.004).ConclusionsSchools hours cause deficitsleeping time during weekdays which is partly made up for at weekend. At weekends there is an interruption of the adolescent's sleeping habits. School performance of adolescents with sleep disorders is lower

Epidemiological survey and risk factors associated with hepatitis E virus in small ruminants in southern Spain

Autochthonous cases of hepatitis E (HE) associated with zoonotic genotypes HEV-3 and HEV-4 have significantly increased in industrialized countries over the last decade. Suidae are generally recognized as the main reservoirs of these genotypes. Susceptibility to HE virus (HEV) infection and zoonotic potential have also been confirmed in other species, including sheep and goat. However, the information about their role in the epidemiology of HEV remains very scarce. The objective of this study was to assess the prevalence, spatial distribution and risk factors associated with HEV exposure in sheep and goats in southern Spain, the country with the highest census of small domestic ruminants in the European Union. Blood samples from 240 sheep and 240 goats were collected between 2015 and 2017. Sera were analysed in parallel using a commercial double-antigen ELISA and real-time PCR. A total of 38 (7.9%; 95%CI: 5.5–10.3) out of 480 sampled animals showed anti-HEV antibodies. By species, the seroprevalences found in sheep and goats were 2.1% (5/240; 95%CI: 0.3–3.9) and 13.8% (33/240; 95%CI: 9.4–18.1) respectively. Anti-HEV antibodies were found on 19 (59.4%; 95%CI: 42.4–76.4) of the 32 sampled farms. The GEE model showed that species (goat) and number of small ruminants in the farm (≤348 animals and ≥538 animals) were risk factors potentially associated with HEV exposure in small ruminants in the study area. HEV RNA was not detected in any of the 480 (0.0%; 95%CI: 0.0–0.8) tested animals. Our results confirm that sheep and goats are naturally, but not equally exposed to HEV and indicate the widespread spatial distribution of HEV among small ruminant populations in southern Spain. Further studies are required to elucidate the role of sheep and goat in the epidemiology of HEV and their potential implications for public health

La prescripción electrónica asistida: instrumento clave para la disminución de los problemas relacionados con los medicamentos en el hospital

Objetivo: Evaluar el efecto de la implantación de la prescripción electrónica asistida (PEA) en una unidad clínica sobre los problemas relacionados con los medicamentos (PRM) y sobre el grado de aceptación de las intervenciones farmacéuticas. Métodos: Estudio prospectivo, casi experimental. Se revisaron las prescripciones farmacológicas de un servicio de medicina interna durante dos periodos secuenciales de 3,5 meses cada uno (antes y después de la implantación de la PEA). Se registraron todos los PRM detectados en ambas fases. Se analizó también la aceptación de la intervención farmacéutica ante cada error. Resultados: Durante los 7 meses del estudio se detectaron un total de 4.023 PRM, 3.785 en la fase de prescripción manual (PM) y 238 en la fase de PEA; la tasa de PRM por paciente ingresado era de 16,9 en PM y de 1,07 en PEA, lo que supone una reducción estadísticamente significativa del 93,67%. Si omitimos los PRM de identificación de la orden médica, se obtiene una reducción del 43,21%. Con la introducción de la PEA, desaparecieron los PRM de identificación de la orden médica y de transcripción en farmacia, disminuyeron los de dosis no adecuada, duración no adecuada e interacciones, y aumentaron los de error en la identificación del medicamento. Conclusiones: La implantación de la PEA ha disminuido de forma significativa la tasa total de PRM y la de PRM de importancia mayor. La proporción de intervenciones farmacéuticas no contestadas por el médico ha disminuido significativamente

La prescripción electrónica asistida: instrumento clave para la disminución de los problemas relacionados con los medicamentos en el hospital

Objetivo: Evaluar el efecto de la implantación de la prescripción electrónica asistida (PEA) en una unidad clínica sobre los problemas relacionados con los medicamentos (PRM) y sobre el grado de aceptación de las intervenciones farmacéuticas. Métodos: Estudio prospectivo, casi experimental. Se revisaron las prescripciones farmacológicas de un servicio de medicina interna durante dos periodos secuenciales de 3,5 meses cada uno (antes y después de la implantación de la PEA). Se registraron todos los PRM detectados en ambas fases. Se analizó también la aceptación de la intervención farmacéutica ante cada error. Resultados: Durante los 7 meses del estudio se detectaron un total de 4.023 PRM, 3.785 en la fase de prescripción manual (PM) y 238 en la fase de PEA; la tasa de PRM por paciente ingresado era de 16,9 en PM y de 1,07 en PEA, lo que supone una reducción estadísticamente significativa del 93,67%. Si omitimos los PRM de identificación de la orden médica, se obtiene una reducción del 43,21%. Con la introducción de la PEA, desaparecieron los PRM de identificación de la orden médica y de transcripción en farmacia, disminuyeron los de dosis no adecuada, duración no adecuada e interacciones, y aumentaron los de error en la identificación del medicamento. Conclusiones: La implantación de la PEA ha disminuido de forma significativa la tasa total de PRM y la de PRM de importancia mayor. La proporción de intervenciones farmacéuticas no contestadas por el médico ha disminuido significativamente

Methodology to improve water and energy use by proper irrigationscheduling in pressurised networks

With the aim of reducing energy consumption and improving water use in pressurised irrigation systems, the methodology to minimise energy consumption by grouping intakes of pressurised irrigation networks into sectors, as developed by Jimenez Bello et al. (2010a), was modified to enable irrigation intakes to operate during the scheduled period for each intake instead of operating during restricted irrigation periods of the same length. Moreover, a method was developed to detect the maximum number of intakes that can operate without extra energy if the source has sufficient head to feed at least some of the intakes. These methods were applied to a Mediterranean irrigation system, where the total cropped area was mainly citrus orchards. In this case study, water was allocated to two groups of intakes, one fed by gravity and the other by pumps. A saving of 36.3 % was achieved by increasing the total volume supplied by gravity, decreasing the injection pump head, and improving the pump performance. Therefore, all the intakes only operated during the irrigation periods at the minimum required pressure.This research was supported by funds from Climate-KIC AGADAPT and from EU 7th Framework Programme FIGARO projects. The authors wish to acknowledge the support provided by Picassent Sector XI staff. The revision of this paper was funded by "The Universitat Politecnica de Valencia, Spain".Jiménez Bello, MA.; Royuela Tomás, Á.; Manzano Juarez, J.; García Prats, A.; Martínez Alzamora, F. (2015). Methodology to improve water and energy use by proper irrigationscheduling in pressurised networks. Agricultural Water Management. 149:91-101. doi:10.1016/j.agwat.2014.10.026S9110114

Serosurveillance of Trichinella sp. in wild boar and Iberian domestic suids in Mediterranean ecosystems of southwestern Spain

Aims: A cross-sectional study was carried out to assess the seroprevalence and risk factors associated with Trichinella spp. exposure in wild boar and Iberian domestic pigs from Mediterranean ecosystems of southwestern Spain. Methods and Results: Serum samples from 1360 wild boar and 439 Iberian domestic pigs were obtained during 2015–2020, from regions where Iberian pigs are raised under extensive conditions, hence sharing habitat with wild boar. Seropositivity was found in 7.4% (100/1360; 95% CI: 6.1–8.9) of the wild boar analysed. In this species, the individual seroprevalence ranged from 3.6% (8/223) (hunting season 2016–2017) to 11.4% (37/326) (2018–2019). A significant higher seropositivity was observed during the hunting season 2018–2019 (p < 0.009: OR = 3.07; 95% CI = 1.32–7.18) and one statistically significant cluster was detected within the studied area, in south central Andalusia [Relative Risk (RR) = 2.9; p = 0.037]. Females showed a significantly higher seroprevalence than males (8.7% vs. 5.8%) (p < 0.001: OR = 1.58; 95% CI = 1.08–2.32). No seropositivity to Trichinella spp. was detected in Iberian domestic pigs (0.0%; 95% CI: 0.0–0.9). Conclusions: Although wild boar play an important role as a reservoir of Trichinella sp. in the Mediterranean ecosystems of southwestern Spain, our results suggest that the wild boar production system does not seem to pose a risk of Trichinella exposure to domestic pigs, despite sharing habitats in these ecosystems