University of Valencia
Repositori d'Objectes Digitals per a l'Ensenyament la Recerca i la CulturaNot a member yet
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Cryobiotechnology for the long-term preservation of oak (Quercus sp.) genetic resources
No full textOaks (genus Quercus) are dominant and iconic trees in most European, American, Asian and North African forests, from cool temperate to tropical environments. There are at least 600 species of Quercus globally with high ecological and economical importance. However, 45% of the species evaluated by IUCN are considered threatened, being affected by habitat destruction or diseases and pests, such as acute oak decline or chronic oak dieback in the UK. As a result, conservation of oaks is becoming increasingly important for many countries. Oak seeds are desiccation sensitive (i.e., recalcitrant), and conventional seed bank strategies are not suitable for their long-term preservation. Tissue culture is a useful tool for Quercus species conservation, supporting micropropagation and in vitro conservation. However, cryopreservation is accepted as the most favourable and cost-effective option for oak long-term conservation ex situ. Numerous tissues can be used as germplasm to preserve the genetic diversity of oaks, including winter dormant buds, shoot tips, plumules, embryogenic lines, somatic embryos and embryonic axes. Pollen cryopreservation could also be used as a complementary technology to support conservation and breeding programmes. Interestingly, whilst the seeds of oak are recalcitrant it appears that the pollen has much greater desiccation tolerance. Seed embryonic axes (with shoot and root meristems) are the preferred explants for oak preservation as high genetic diversity can be captured and axes can be grown into full plants with relatively simple micropropagation procedures. However, successful cryopreservation depends on controlling many factors, including physical damage to the embryo during excision, oxidative stress associated to excision and cryopreservation procedures, differential response of shoot and root meristems (within and amongst species) to the stresses imposed by partial desiccation and cooling, and the need to improve in vitro growth and acclimation procedures. Here we review the main cryobiotechnological options for the successful banking of species in the genus Quercus and the needs for future research are highlighted
Fasto barroco, proyección ciudadana y poesía femenina: la ciudad moderna es (y será) de las mujeres
No full textFasto barroco, proyección ciudadana y poesía femenina: la ciudad moderna es (y será) de las mujere
Las habilidades del teletrabajador para la competitividad
No full textLa adopción de las Tecnologías de la Información y las Comunicaciones (TIC) en las organizaciones favorece la competitividad empresarial. Este artículo expone al teletrabajo como un mecanismo de contratación a través del uso de las TIC y la necesidad de plantear las competencias relacionadas con las actividades del teletrabajador. La investigación se realizó entre 114 empresarios del sector calzado, en Bucaramanga, Colombia, para indagar acerca de sus apreciaciones sobre la adopción de esta modalidad laboral. Los resultados muestran que en la contratación de teletrabajadores se requieren establecer lazos de confianza y el desarrollo de habilidades que van más allá de sus conocimientos informáticos. Los empresarios evidencian que los teletrabajadores deben ser responsables, creativos, innovadores, cumplidores de su deber, y desarrollar las competencias relacionadas con la comunicación, la gestión del tiempo y la lectoescritura para mejorar la competitividad empresarial
Conditioned responsibility, belonging and the vulnerability of our ethical understanding
No full textIn this paper I explore the ethical responsibility of agents who find themselves in situations characterized by what I call the Individual Ethical Gap (IEG). Individual Ethical Gap situations are structured so as to rule out holding individuals responsible for their actions and omissions by virtue of the intentions behind or the consequences of their actions. I argue that, in IEG situations, individuals can nevertheless, depending on the circumstances, be held ethically responsible for their actions and omissions by virtue of the conditions in which they find themselves operating. This notion of an ethics stemming from conditions (rather than from consequences or intentions) gives rise to a particular form of vulnerability to error in our self- and other-ascriptions of ethical responsibility: a vulnerability in our ethical understanding. In this paper, I use Pamela Sue Anderson's discussion of vulnerability and of Kantian autonomy to show that this need not be regarded as a threat to ethics but, on the contrary, as an element of belonging and of understanding that renders possible a more honest encounter with others and with the world
Ammonia and beyond - biomarkers of hepatic encephalopathy.
No full textAmmonia is a product of amino acid metabolism that accumulates in the blood of patients with liver cirrhosis, leading to neurotoxic effects and hepatic encephalopathy (HE). HE manifestations can range from mild, subclinical disturbances in cognition, or minimal HE (mHE) to gross disorientation and coma, a condition referred to as overt HE. Many blood based biomarkers reflecting these neurotoxic effects of ammonia and liver disease can be measured in the blood allowing the development of new biomarkers to diagnose cirrhosis patients at risk of developing HE. The effect of ammonia on the brain is modulated by severity of systemic inflammation, and both hyperammonemia and inflammation can induce oxidative stress, which may mediate the neurological alterations associated to HE. This review aims to provide the latest evidence on biomarkers of HE beyond ammonia. We present different approaches to predict overt HE based on the combination of blood ammonia with some analytical and clinical parameters. Magnetic resonance analysis of brain images could also provide sensitive diagnostic biomarkers based on neuroimaging parameters. Some reports suggest that markers of systemic inflammation, oxidative stress, and central nervous system-derived components, may serve as additional biomarkers of HE. The involvement of extracellular vesicles and microbiota in the pathophysiology of mHE and HE has recently acquired importance and it would be interesting to explore their usefulness as early biomarkers of the disease. It is important to have a biomarker or a combination of them for early diagnosis of mHE to improve its treatment and prevent progression to overt HE
Migration of cations induces reversible performance losses over day/night cycling in perovskite solar cells
No full textPerovskites have been demonstrated in solar cells with a power conversion efficiency of well above 20%, which makes them one of the strongest contenders for next generation photovoltaics. While there are no concerns about their efficiency, very little is known about their stability under illumination and load. Ionic defects and their migration in the perovskite crystal lattice are some of the most alarming sources of degradation, which can potentially prevent the commercialization of perovskite solar cells (PSCs). In this work, we provide direct evidence of electric field-induced ionic defect migration and we isolate their effect on the long-term performance of state-of-the-art devices. Supported by modelling, we demonstrate that ionic defects, migrating on timescales significantly longer (above 103 s) than what has so far been explored (from 10−1 to 102 s), abate the initial efficiency by 10-15% after several hours of operation at the maximum power point. Though these losses are not negligible, we prove that the initial efficiency is fully recovered when leaving the device in the dark for a comparable amount of time. We verified this behaviour over several cycles resembling day/night phases, thus probing the stability of PSCs under native working conditions. This unusual behaviour reveals that research and industrial standards currently in use to assess the performance and the stability of solar cells need to be adjusted for PSCs. Our work paves the way for much needed new testing protocols and figures of merit specifically designed for PSCs
Double Transverse Foramina - An Anatomical Basis for Possible Vertebrobasilar Insufficiency Risk and Vertebral Artery Injury
No full textCervical vertebrae may exhibit the anomalous presence of a double transverse foramen (DTF) that may impact the anatomy of related structures that traverse the cervical region, such as the vertebral artery (VA). This retrospective anatomical study utilized CT angiography cervical scans to examine the prevalence of DTF, VA, and TF areas. The subjects were separated into two groups: normal TF (NTF group; 26 males and 21 females) and double TF (DTF group; 21 males and 24 females). The males presented significantly higher TF area values (30.31 ± 4.52 mm2) than the females (27.48 ± 1.69 mm2) in the NTF group (p = 0.006). The sex differences disappeared when a DTF was present (p = 0.662). There were no differences in the VA area values between the sexes in both the NTF and DTF groups (p = 0.184). No significant differences in the VA area values between males of the NTF and DTF groups (p = 0.485) were noted. The DTF subjects presented an increased VA/TF area ratio than the NTF subjects (p < 0.001). This study showed that DTF presence reduced the TF area. In contrast, the VA area did not change despite the decreasing TF area. This might be an anatomical risk for transient vertebrobasilar insufficiency in subjects with DTF, especially in females, because VA space in the TF is less in DTF subjects than in NTF subjects. This may lead to easy VA compression in DTF subjects following neck trauma
Postnatal hypoxic preconditioning attenuates lung damage from hyperoxia in newborn mice
No full textBACKGROUND: Preterm infants frequently require oxygen supplementation at birth. However, preterm lung is especially sensible to structural and functional damage caused by oxygen free radicals. METHODS: The adaptive mechanisms implied in the fetal-neonatal transition from a lower to a higher oxygen environment were evaluated in a murine model using a custom-designed oxy-chamber. Pregnant mice were randomly assigned to deliver in 14% (hypoxic preconditioning group) or 21% (normoxic group) oxygen environment. Eight hours after birth FiO2 was increased to 100% for 60 min and then switched to 21% in both groups. A control group remained in 21% oxygen throughout the study. RESULTS: Mice in the normoxic group exhibited thinning of the alveolar septa, increased cell death, increased vascular damage, and decreased synthesis of pulmonary surfactant. However, lung histology, lamellar bodies microstructure, and surfactant integrity were preserved in the hypoxic preconditioning group after the hyperoxic insult. CONCLUSION: Postnatal hyperoxia has detrimental effects on lung structure and function when preceded by normoxia compared to controls. However, postnatal hypoxic preconditioning mitigates lung damage caused by a hyperoxic insult
Canon y Premio Nobel: un estado de la cuestión
No full textThis paper poses the following question: as a world institutional award, what is the influence of the Nobel Prize in Literature over the construction of the global canon? To answer it, we start from previous resea rch and analyze the studies on canon and Nobel Prize published in scientific journals indexed in the two main international databases: Web of Science, by Clarivate Analytics, and Scopus, by Elsevier, since both cover the current scientific production. After reading the articles which are relevant for the research objective, the centres of interest of this critical literature can be grouped into three large blocks: the concept of World Literature and its relationship with the Nobel Prize; the canonical characteristics of the works by Nobel Prize winners, and the influence of Nobel Prize in the process of creating the world canon. The conclusions question the monolithic and monumental character of the literary canon and advocate for a more transparent approach to its construction that considers economic and ideological aspects (beyond the formal or artistic value of the texts) as crucial for understanding its nature and evolution. For example, E. Lameborshi's concept of ideological fluency and R. Walkowitz's born translated novels are useful for understanding to what extent the common concepts of World Literature and canon have recently been redefined
Evaluación de las propiedades psicométricas del Test de Dependencia al Teléfono Móvil en estudiantes universitarios cubanos
No full textProblemática: El teléfono móvil es utilizado con frecuencia por los adolescentes y jóvenes atendiendo a los atractivos servicios que ofrece. Sin embargo, su uso abusivo puede generar problemas físicos, psicológicos y sociales. De ahí la importancia de contar con instrumentos que permitan evaluar esta problemática. Objetivo(s): Evaluar las propiedades psicométricas que presenta el Test de Dependencia al Teléfono Móvil en una muestra de estudiantes universitarios cubanos. Metodología: Enfoque cuantitativo. Estudio instrumental. Participaron 536 estudiantes universitarios cubanos. Resultados y discusión: Se realizó la adaptación lingüística y sociocultural del instrumento. Fueron identificados cuatro factores (Tolerancia, Abstinencia, Dificultades relacionadas con su uso y Dificultades en el control) y adecuados niveles de confiabilidad. El Factor 2 Abstinencia mostró medias mayores en los estudiantes que se encontraban más cercanos a la etapa de la adolescencia. No se encontraron diferencias en cuanto al sexo y los factores obtenidos. Conclusiones: El Test de Dependencia al Teléfono Móvil mostró adecuadas propiedades psicométricas que permiten su utilización en el contexto universitario cubano. Palabras clave: dependencia al teléfono móvil; estudiantes universitarios; Test de Dependencia al Teléfono Móvi