El cuestionario de relaciones en el centro (c.r.c.): un instrumento para identificar alumnos en riesgo de ser victimizados

The situation of bullying in schools is assessed using questionnaires in which students are asked to indicate: a) if they have observed situations of harassment and intimidation and to indicate their type and frequency, frequent places where have observed harassment b) if they have suffered harassment situations and express their type and frequency and frequent places where he has been harassed. With these questions runs the risk of biasing the perception of the students because they are almost exclusively required to take into account negative experiences. The C.R.A. is an assessment tool that identifies school climate to student bullying suffered or is at risk of suffering based on student demonstrations concerning: a) The feeling of comfort and security that students have in the center. b) The perception of the teachers' attitude towards students and to the relationships established. c) The ideas and knowledge that avoid becoming involved in a relationship of victimization.La situación de acoso en los centros se suele averiguar utilizando cuestionarios en los que se pide a los alumnos que indiquen: a) si han observado situaciones de acoso e intimidación y que indiquen su tipo y frecuencia, los lugares frecuentes donde han observado el acoso y b) si han sufrido situaciones de acoso y que expresen su tipo y frecuencia y los lugares frecuentes donde ha sido acosado. Con este tipo de preguntas se corre el riesgo de sesgar la percepción de los estudiantes debido a que casi exclusivamente se les pide que tengan en cuenta experiencias negativas. El Cuestionario C.R.A. es un instrumento de valoración del clima escolar que permite identificar al alumnado que sufre acoso escolar o corre el riesgo de padecerlo basándose en las manifestaciones de los alumnos sobre: a) El sentimiento de bienestar y seguridad que tienen los alumnos en el centro.b) La percepción de la actitud del profesorado hacia los alumnos y hacia las relaciones que establecen.c) Las ideas y conocimientos que evitan verse implicados en unas relaciones de victimización

Uncertainty propagation using the full second-order approach for probabilistic fatigue crack growth life

Uncertainty propagation of fatigue crack growth life commonly aims to provide the probability distribution of the lifespan needed for probabilistic damage tolerance analysis and for structural integrity assessment. This paper presents a novel methodology for efficiently estimating the parameters of the probability distribution of fatigue lifespan considering the Pearson distribution family. First, the full second-order approach for expected value and variance prediction of probabilistic fatigue crack growth life is extended to predict higher order statistical moments of the underlying distribution. That is, the expected value (first raw moment) and the variance (second central moment) equations are complemented with the probabilistic formulations for the skewness and for the kurtosis (third and fourth central standardized moments, respectively). Then, from these moments, the Pearson distribution type is automatically determined. Finally, the parameters of the particular Pearson distribution type are estimated making the statistical moments of the constructed lifespan distribution match the first four prescribed moments predicted by the probabilistic equations. The validity of the proposed method is verified by a numerical example regarding the fatigue crack growth in a railway axle under random bending loading. It is proven that the probability density function of the lifespan is properly derived by the methodology, without knowing or assuming the output probability distribution beforehand. The methodology presented enables an efficient and an accurate quantification of the lifespan uncertainties via its probabilistic distribution. This probabilistic description of fatigue crack growth life can be subsequently used in reliability studies or in damage tolerance assessment

Pérdidas de carga localizadas en inserciones de ramales de goteo

Las pérdidas de carga localizadas suelen expresarse mediante un coeficiente K que se aplica al sumando cinético de Bernoulli, o como las que resultarían de un incremento de longitud de tubería en el que se producirían las mismas pérdidas, es decir, lo que se conoce como longitud equivalente le. Para la evaluación en el punto de inserción de goteros en ramales, Juana et al. 2002a han propuesto dos procedimientos, uno teórico con el que se estima K, basado en la ecuación de Bélanger-Borda y los coeficientes de contracción del desagüe por orificios, y otro experimental, que calcula le a partir de las medidas de presión y caudal en cabeza y de pérdidas de carga en el ramal de goteo. Como continuación a dichos estudios, se evalúan en este trabajo las pérdidas de carga localizadas en la inserción del ramal en la tubería porta-ramales. A este fin, se usan los procedimientos descritos para goteros en los trabajos precedentes. Finalmente, se valora el uso de los resultados obtenidos, tanto en ramales como en la tubería porta-ramales, para predecir resultados de riego

Intracellular deprotection reactions mediated by palladium complexes equipped with designed phosphine ligands

Discrete palladium(II) complexes featuring purposely designed phosphine ligands can promote depropargylation and deallylation reactions in cell lysates. These complexes perform better than other palladium sources, which apparently are rapidly deactivated in such hostile complex media. This good balance between reactivity and stability allows the use of these discrete phosphine palladium complexes in living mammalian cells, whereby they can mediate similar transformations. The presence of a phosphine ligand in the coordination sphere of palladium also provides for the introduction of targeting groups, such as hydrophobic phosphonium moieties, which facilitate the accumulation of the complexes in mitochondria

Síntesis de capas de SiC en substrato de Si mediante implantación iónica

En este trabajo se investiga la síntesis de estructuras SiC/Si mediante implantación iónica de carbono en Si. Las implantaciones se han realizado a energías entre 25 y 300 keV y las dosis en el rango lO^^ylO^^ cm , manteniendo el substrato a temperatura ambiente o 500°C. Algunas estructuras han sido recocidas a 1150°C. Los resultados indican que implantando a temperatura ambiente se forma una capa de SiC amorfa y de composición gradual, que recristaliza formando precipitados de ß-SiC con orientaciones aleatorias después del recocido. Además se forma un capa superficial rica en carbono, debida a la difusión del carbono hacia la superficie durante la implantación, y que desaparece con el recocido. Implantando a 500°C se forma directamente una capa con una muy alta densidad de precipitados de ß-SiC orientados preferencialmente con la matriz de silicio. Dada la estabilidad térmica y química de dicha capa se han realizado membranas de SiC mediante técnicas fotolitográficas y ataque químico selectivo, cuya rugosidad superficial es inferior a 6 nm. Estas membranas muestran unos gradientes de tensiones residuales, que prácticamente desaparecen después del recocido. Los resultados confirman la potencialidad de la implantación iónica para la formación de estructuras microme-cánicas de SiC sobre Si

Estudio óptico del tamaño y forma de las partículas de polvos de talco

Sorne dusting powders tale have been studied by optic methods. The investigation of the shapes and sizes of the particles, has served to establish two index, which we are named roundish rate and fmeness rateo. These results are very interesting at the topie aplication of the dusting powders tale, because they permit to appreciate a possible irritative action in the skin.Han sido estudiados algunos polvos de talco por métodos opticos. La investigación de las formas y tamaños de las partículas, ha servido para establecer dos índices que hemos denominado, grado de redondearniento y grado de finura. Estos resultados son muy interesantes en la aplicación tópica de los polvos de talco, porque permiten la estimación de una posible acción irritante de la piel

Molecular elucidation of CO2 methanation over a highly active, selective and stable LaNiO3/CeO2-derived catalyst by in situ FTIR and NAP-XPS

The CO2 methanation mechanism over the highly active (TOF=75.1 h−1), selective (>92%) and stable 10% LaNiO3/CeO2-derived catalyst is still unresolved. The surface of the catalyst is monitored under hydrogenation (H2), oxidizing (CO2) and CO2 methanation (H2 +CO2) conditions by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS) using synchrotron radiation. Meanwhile, the main reaction intermediates are identified by in situ FTIR analysis. NAP-XPS experiments confirm that LaNiO3 perovskite reduction leads to the ex-solution of Ni0 nanoparticles and Ni2+single bondCeO2−x and Ni2+single bondLa2O3 interfaces conformation, favouring the CO2 adsorption and the H2 dissociation/transfer. In situ FTIR experiments combined with the C1s spectra (NAP-XPS) suggest that the CO2 activation occurs on CeO2−x (oxygen vacancies and OH–) at low temperatures, in the form of bicarbonates; whereas, mono-/bidentate carbonates are formed on different strength La2O3 sites at increasing temperatures. These species are consecutively reduced to formates, as the main reaction intermediate, and methane by the H spilled from Ni0 nanoparticles near to NiOsingle bondCeO2−x and NiOsingle bondLa2O3 interfaces.Support for this study was provided by Projects PID2019–105960RB-C21 and PID2019–105960RB-C22 by MCIN/AEI/10.13039/501100011033, the Basque Government (Project IT1509–2022), Generalitat Valenciana (CIPROM/2021/74) and ALBA synchrotron. One of the authors (JAOC) acknowledges the postdoctoral research grant (DOCREC20/49) provided by the University of the Basque Country (UPV/EHU)

Study of the Spanish Society of Medical Oncology (SEOM) on the access to oncology drugs and predictive biomarkers in Spain

Altres ajuts: This study was funded by SEOM.The Spanish Society of Medical Oncology (SEOM) has carried out a study to analyse the conditions of access to oncology drugs in clinical practice in Spain. For the first time, the access of predictive biomarkers has also been analyzed. A questionnaire was sent to 146 hospitals in Spain to collect information on the process of approval of 11 oncology drugs of an unquestionable clinical benefit and five predictive biomarkers of mandatory determination for specific treatments. Results highlight the still existing differences in the access of oncology drugs, as well as the newly identified differences in the access to predictive biomarkers between Autonomous Communities (AACC) in Spain, as well as between different hospitals within the same Autonomous Community. Conclusions The SEOM considers it necessary to reduce the differences identified, increase homogeneity, and improve conditions of access to oncology drugs and biomarkers, and makes proposals to address these issues

Role of the microtubule-targeting drug vinflunine on cell-cell adhesions in bladder epithelial tumour cells

Background: Vinflunine (VFL) is a microtubule-targeting drug that suppresses microtubule dynamics, showing anti-metastatic properties both in vitro and in living cancer cells. An increasing body of evidence underlines the influence of the microtubules dynamics on the cadherin-dependent cell-cell adhesions. E-cadherin is a marker of epithelial-to-mesenchymal transition (EMT) and a tumour suppressor; its reduced levels in carcinoma are associated with poor prognosis. In this report, we investigate the role of VFL on cell-cell adhesions in bladder epithelial tumour cells. Methods: Human bladder epithelial tumour cell lines HT1376, 5637, SW780, T24 and UMUC3 were used to analyse cadherin-dependent cell-cell adhesions under VFL treatment. VFL effect on growth inhibition was measured by using a MTT colorimetric cell viability assay. Western blot, immunofluorescence and transmission electron microscopy analyses were performed to assess the roles of VFL effect on cell-cell adhesions, epithelial-to-mesenchymal markers and apoptosis. The role of the proteasome in controlling cell-cell adhesion was studied using the proteasome inhibitor MG132. Results: We show that VFL induces cell death in bladder cancer cells and activates epithelial differentiation of the remaining living cells, leading to an increase of E-cadherin-dependent cell-cell adhesion and a reduction of mesenchymal markers, such as N-cadherin or vimentin. Moreover, while E-cadherin is increased, the levels of Hakai, an E3 ubiquitin-ligase for E-cadherin, were significantly reduced in presence of VFL. In 5637, this reduction on Hakai expression was blocked by MG132 proteasome inhibitor, indicating that the proteasome pathway could be one of the molecular mechanisms involved in its degradation. Conclusions: Our findings underscore a critical function for VFL in cell-cell adhesions of epithelial bladder tumour cells, suggesting a novel molecular mechanism by which VFL may impact upon EMT and metastasis