356 research outputs found
Domain configuration and magnetization switching in arrays of permalloy nanostripes
The proximity effect in the collective behavior of arrays of magnetic nanostripes is currently a subject of intensive research. The imperative of reducing the size and distances between elements in order to achieve higher storage capacity, faster access to the information as well as low energy consumption, brings consequences about the isolated behavior of the elements and devices. Parallel to each other permalloy nanostripes with high aspect ratio have been prepared by the nanolithography technique. The evolution of the closure domains and the magnetization direction in individual nanostructures has been imaged under applied magnetic fields using Variable Field Magnetic Force Microscopy. Moreover, the magnetostatic interactions between neighboring elements and the proximity effects in arrays of such nanostructures have been quantitatively analyzed by Magnetic Force Microscopy and micromagnetic simulations. The agreement between simulations and the experimental results allows us to conclude the relevance of those interactions depending on the geometry characteristics. In particular, results suggest that the magnetostatic coupling between adjacent nanostripes vanishes for separation distances higher than 500 nm
Novel parameters for evaluating the Spatial and Thematic accuracy of land cover maps.
Se proponen novedosas fórmulas para evaluar la certeza de la cartografí
A bioprinted 3D gut model with crypt-villus structures to mimic the intestinal epithelial-stromal microenvironment
The intestine is a complex tissue with a characteristic three-dimensional (3D) crypt-villus architecture, which plays a key role in the intestinal function. This function is also regulated by the intestinal stroma that actively supports the intestinal epithelium, maintaining the homeostasis of the tissue. Efforts to account for the 3D complex structure of the intestinal tissue have been focused mainly in mimicking the epithelial barrier, while solutions to include the stromal compartment are scarce and unpractical to be used in routine experiments. Here we demonstrate that by employing an optimized bioink formulation and the suitable printing parameters it is possible to produce fibroblast-laden crypt-villus structures by means of digital light projection stereolithography (DLP-SLA). This process provides excellent cell viability, accurate spatial resolution, and high printing throughput, resulting in a robust biofabrication approach that yields functional gut mucosa tissues compatible with conventional testing techniques.Copyright © 2023 Elsevier B.V. All rights reserved
La experiencia belga en la construcción y reparación de carreteras de hormigón
Belgium is one of the foremost countries in Europe in the development of concrete road pavements, both due to its tradition in this technology and the extent, modern and original quality of the road network. Hence it has been thought useful to draft a historical survey of Belgian accomplishments in this field, and to summarize the main inferences to be drawn from their experience, in reference both to the construction and the repair of concrete roads.<br><br>Siendo Bélgica uno de los primeros países europeos en la construcción de pavimentos de hormigón (tanto por la tradición que en él tiene este tipo de firmes como por la extensión de su red y la modernidad y originalidad de sus técnicas), nos ha parecido interesante redactar un bosquejo histórico de las realizaciones belgas en este campo y resumir las principales conclusiones a. las que conduce la experiencia de dicho país, tanto en lo relativo a construcción como a reparaciones.
Desde el punto de vista cronológico la historia de las carreteras belgas de hormigón se puede dividir en tres grandes etapas, perfectamente diferenciadas por las características propias de las realizaciones llevadas a cabo en cada una de ellas.
Estas tres etapas son las siguientes: 1ª Anterior al año 1930; 2ª De 1930 a 1955; 3ª A partir de 1955
Surgical treatment of type 2 giant mesenteric cyst: case report and literature review
Mesenteric lesions, including cysts, are rare abdominal tumours and in most cases non-neoplastic. They may have an asymptomatic course or present with pain, abdominal distension or intestinal obstruction. The suggested management is surgical resection of the lesions by laparotomy or minimally invasive surgery. We presented the case of a 48-year-old patient with progressive abdominal distension attributed to liver cirrhosis. Ultrasound and computed tomography of the abdomen showed evidence of a giant cyst of the mesentery with no evidence of tumor activity. We therefore decided to perform an exploratory laparotomy with cystectomy and omentectomy, follow-up and pathology report negative for malignancy
Chilaiditi's sign in complicated acute appendicitis: case report and literature review
Chilaiditi's condition refers to the presence of a loop of small intestine or colon between the diaphragm and the hepatic rim, usually due to alterations in the attachment of the liver to the diaphragm. Chilaiditi syndrome is associated with abdominal pain as the most common clinical manifestation. Pneumoperitoneum should always be ruled out in the context of these patients. We presented the case of a male in his eighth decade of life who presented with data suggestive of drug-modified acute appendicitis, for which computed tomography of the abdomen identified acute appendicitis and Chilaiditi's condition. An open appendectomy was performed without complications and the condition resolved
Recommended from our members
A simple approach to forest structure classification using airborne laser scanning that can be adopted across bioregions
Reliable assessment of forest structural types (FSTs) aids sustainable forest management. We developed a methodology for the identification of FSTs using airborne laser scanning (ALS), and demonstrate its generality by applying it to forests from Boreal, Mediterranean and Atlantic biogeographical regions. First, hierarchal clustering analysis (HCA) was applied and clusters (FSTs) were determined in coniferous and deciduous forests using four forest structural variables obtained from forest inventory data – quadratic mean diameter (QMD), Gini coefficient (GC), basal area larger than mean (BALM) and density of stems (N) –. Then, classification and regression tree analysis (CART) were used to extract the empirical threshold values for discriminating those clusters. Based on the classification trees, GC and BALM were the most important variables in the identification of FSTs. Lower, medium and high values of GC and BALM characterize single storey FSTs, multi-layered FSTs and exponentially decreasing size distributions (reversed J), respectively. Within each of these main FST groups, we also identified young/mature and sparse/dense subtypes using QMD and N. Then we used similar structural predictors derived from ALS – maximum height (Max), L-coefficient of variation (Lcv), L-skewness (Lskew), and percentage of penetration (cover), – and a nearest neighbour method to predict the FSTs. We obtained a greater overall accuracy in deciduous forest (0.87) as compared to the coniferous forest (0.72). Our methodology proves the usefulness of ALS data for structural heterogeneity assessment of forests across biogeographical regions. Our simple two-tier approach to FST classification paves the way toward transnational assessments of forest structure across bioregions
Physiological Responses to Anxiety and Gender Differences in Second Language Oral Performance. Respuestas Fisiológicas a la ansiedad y diferencias de Género en la Producción Oral en Segundas Lenguas
The aim of this study is to examine the relationship between physiological responses to anxiety and gender variable in second language oral performance. This research project investigates the conceptualization of second language anxiety in the context of oral production, considering physiological responses to anxiety and differences derived from gender on foreign language speaking anxiety. There were 371 participants in the study, 185 female and 186 male participants. Among the participants there were 313 students at the University of Cordoba, Spain, studying ESP, 23 teachers at the University of Cordoba taking an ESP course and 8 administration and services staff. A questionnaire (CAEX) was administered to participants. Results of the quantitative data in this research show that female learners demonstrated higher levels of anxiety than male learners. The results of this study help teachers to select their teaching and testing strategies more effectively according to the gender of learners.El objetivo de este estudio es examinar la relación entre las respuestas fisiológicas a la ansiedad y la variable de género en la producción oral de una segunda lengua. Esta investigación indaga en la conceptualización de la ansiedad en una segunda lengua en el contexto de la producción oral, considerando las respuestas fisiológicas a la ansiedad y las diferencias derivadas del género en la ansiedad al hablar en una lengua extranjera. El estudio contó con 371 participantes, 185 mujeres y 186 hombres. Entre los participantes había 313 estudiantes de la Universidad de Córdoba, España, 23 profesores de la Universidad de Córdoba y 8 personas de administración y servicios que estudiaban IFE. Se administró un cuestionario (CAEX) a los participantes. Los resultados de los datos cuantitativos de esta investigación muestran que las alumnas demostraron niveles más altos de ansiedad que los alumnos. Los resultados de este estudio ayudan a los profesores a seleccionar mejor sus estrategias de enseñanza y examen en función del género de los alumnos
Bose-Einstein condensate dark matter phase transition from finite temperature symmetry breaking of Klein-Gordon fields
In this paper the thermal evolution of scalar field dark matter particles at
finite cosmological temperatures is studied. Starting with a real scalar field
in a thermal bath and using the one loop quantum corrections potential, we
rewrite Klein-Gordon's (KG) equation in its hydrodynamical representation and
study the phase transition of this scalar field due to a Z_2 symmetry breaking
of its potential. A very general version of a nonlinear Schr\"odinger equation
is obtained. When introducing Madelung's representation, the continuity and
momentum equations for a non-ideal SFDM fluid are formulated, and the
cosmological scenario with the SFDM described in analogy to an imperfect fluid
is then considered where dissipative contributions are obtained in a natural
way.Additional terms appear compared to those obtained in the classical version
commonly used to describe the \LambdaCDM model, i.e., the ideal fluid. The
equations and parameters that characterize the physical properties of the
system such as its energy, momentum and viscous flow are related to the
temperature of the system, scale factor, Hubble's expansion parameter and the
matter energy density. Finally, some details on how galaxy halos and smaller
structures might be able to form by condensation of this SF are given.Comment: Substantial changes have been made to the paper, following the
referees recommendations. 16 pages. Published in Classical and Quantum
Gravit
- …