Solution of a model for the two-channel electronic Mach-Zehnder interferometer

We develop the theory of electronic Mach-Zehnder interferometers built from quantum Hall edge states at Landau level filling factor \nu = 2, which have been investigated in a series of recent experiments and theoretical studies. We show that a detailed treatment of dephasing and non-equlibrium transport is made possible by using bosonization combined with refermionization to study a model in which interactions between electrons are short-range. In particular, this approach allows a non-perturbative treatment of electron tunneling at the quantum point contacts that act as beam-splitters. We find an exact analytic expression at arbitrary tunneling strength for the differential conductance of an interferometer with arms of equal length, and obtain numerically exact results for an interferometer with unequal arms. We compare these results with previous perturbative and approximate ones, and with observations.Comment: 13 pages, 9 figures, final version as publishe

Using spatial data mining to analyze area-diversity patterns among soil, vegetation, and climate: A case study from Almería, Spain

ABSTRACT: Area-pedodiversity, area?vegetation diversity, area-bioclimatic belts, diversity and pedodiversity-vegetation diversity-bioclimatic diversity relationships were analyzed for the most arid region ofWestern Europe (SE Spain). The study is novel in that it analyzed these relationships using as operational geographic units (OGUs) the set of polygons belonging to the same character state (i.e., typology) that defines a zone in a given thematic map. We considered three thematic maps: 1) the map of soil associations (SMU) with 303 different soil associations (i.e., 303 areas or zones); 2) the map of potential vegetation (PNV)with 40 vegetation series or zones and 3) the map of bioclimatic belts (BB) with 7 bioclimatic zones. Using GIS tools, we analyzed the contents (richness) of soil mapping units (polygons) with regard to vegetation series and bioclimatic belts as well as the contents of vegetation series and bioclimatic belts with regard to SMU. The results indicate that the relationships between the area and the richness of zones follow a power law, the ?fingerprint of fractal geometry?, irrespective of the way the area has been defined and their relative magnitude (the areas defined by SMU are the smallest, while the areas defined by bioclimatic belts are the largest). The results also indicate a significant correlation between the ? diversities of the zones and between their ? diversities. We conclude that the methods used to measure such correlations, based on ? and ? diversities are useful to investigate and quantify the relationships between the pedosphere, vegetation and climate

Aplicación del análisis de los rasgos ecológicos ("traits") de las presas para el estudio del comportamiento alimentario en peces bentóofagos : el ejemplo del espinoso (Gasterosteus gymnurus Cuvier, 1829)

We have used fourteen ecological traits of the macroinvertebrates present in the stomachs of the stickleback to try to obtain information on it's feeding behaviour in the upper part of the Miño basin (NW Spain). To this end, a principal components analysis was carried out, using the level of affinity of the taxa for the different categories of the traits through a fuzzy codification process. The results show that the stickleback is a bottom-feeder that feeds basically on benthic prey, but can also consume terrestrial prey on the surface, the Chironomid larvae being the most abundant prey (constituted 59.66% of the total). This species exhibited a generalist behaviour concerning some of the ecological traits of the prey (ex. 'substratum', 'aggregation tendency', 'trajectory on the substratum and in the drift', 'agility' or 'body flexibility'). In other cases it showed a clear preference for prey with certain characteristics, such as taxa typical of areas where the velocity of the current is null or low (trait 'current velocity') or taxa available in the drift during daylight (trait 'daily drift behavior'). The results obtained show that this type of analysis could be used on other bottom-feeder species, thus providing a more ecological approach to feeding studies.Hemos utilizado catorce rasgos ecológicos ("traits") de los macroinvertebrados presentes en los estómagos del espinoso para intentar obtener información sobre su comportamiento alimentario en la cuenca alta del Miño (NO España). Para ello se ha realizado un análisis de componentes principales utilizando el grado de afinidad de los taxones por las diferentes categorías de los rasgos mediante un procedimiento de codificación difusa. Los resultados muestran que el espinoso es un comedor de fondo que se alimenta básicamente de presas bentónicas, pero que también puede consumir presas terrestres en superficie, siendo los Quironómidos en estado de larva las presas más abundantes (constituyeron el 59.66% del total). Esta especie presentó un comportamiento generalista en cuanto a alguno de los rasgos ecol'ogicos de las presas (ej. rasgos 'substrato', 'tendencia de agregación', 'trayectoria en el substrato y en la deriva', 'agilidad' o 'flexibilidad corporal'), mientras que en otros casos mostr'o una clara preferencia por presas con ciertas características, como por ejemplo taxones típicos de zonas donde la velocidad de corriente es nula o baja (rasgo 'velocidad de corriente') o taxones disponibles en la deriva durante las horas de luz (rasgo 'comportamiento diario de la deriva'). Los resultados obtenidos demuestran que este tipo de análisis podría ser empleado en otras especies de peces bentófagos, proporcionando un enfoque más ecológico a los estudios de alimentación

Hyperglycemia and Hyperinsulinemia-Like Conditions Independently Induce Inflammatory Responses in Human Chondrocytes

To elucidate the mechanisms by which type 2 Diabetes Mellitus (DM2) constitutes a risk factor for the development and progression of osteoarthritis (OA), this work determined whether high glucose and/or high insulin, the hallmarks of DM2, are capable of activating the transcription factor, Nuclear Factor-κB (NF-κB), which plays a critical role in OA by inducing the expression of pro-inflammatory and catabolic genes. For this, we analyzed NF-κB activation by measuring the nuclear levels of p65 by western blot. As readouts of NF-κB activity, Interleukin-1β, Tumor Necrosis Factor-α, and inducible nitric oxide synthase (iNOS) expression were analyzed by real time RT-PCR and western blot. Culture of the human chondrocytic cell line, C28-I2, in high glucose (30 mM) increased nuclear NF-κB p65 levels in a time-dependent manner, relative to cells cultured in medium containing 10 mM glucose (regular culture medium). High glucose-induced NF-κB activation was inhibited by co-treatment with its specific inhibitor, Bay 11-7082, 5 µM. Culture of primary human chondrocytes under high glucose for 24 h increased IL-1β and TNF-α mRNA levels by 97% (p = 0.0066) and 85% (p = 0.0045), respectively, while iNOS mRNA and protein levels and NO production increased by 61% (p = 0.0017), 148% (p = 0.0089), and 70% (p = 0.049), respectively, relative to chondrocytes maintained in 10 mM glucose. Treatment of chondrocytic cells with 100 nM insulin was also sufficient to increase nuclear NF-κB p65 levels, independently of the glucose concentration in the culture medium. This study shows that hyperglycemia and hyperinsulinemia are independently sufficient to induce inflammatory responses in human chondrocytes, namely by activating NF-κB. This can be a relevant mechanism by which DM type 2 and other conditions associated with impaired glucose and insulin homeostasis, like obesity and the metabolic syndrome, contribute to the development and progression of OA.info:eu-repo/semantics/publishedVersio

Gramática interactiva para noruegos : un proyecto colaborativo en Canvas

La sección de español de la Universidad de Oslo (UiO) lleva trabajando desde el otoño de 2021 en una gramática interactiva en Canvas. La gramática es resultado de un proyecto colaborativo entre docentes y estudiantes, aunque su acceso es abierto y no está limitado únicamente a este último grupo (https://uio.instructure.com/courses/35550 ). En este artículo se expone cómo esta gramática ahonda en los usos de Canvas e intenta explorar nuevas utilidades de la plataforma. También da cuenta de los objetivos de la gramática, propuestas pedagógicas y principales elecciones durante el proceso de elaboración. Por último, se expone cómo la elaboración de la gramática ha servido también para retar la relación tradicional profesor-estudiante y poner en práctica una relación alternativa que acerca a los estudiantes al mundo laboral.During the 2021 autumn, the Spanish section at the University of Oslo (UiO) started an interactive grammar project developed in Canvas LMS. This grammar is the outcome of a collaborative project among instructors and students -it is open to the general public and not only focused to the use of students of Spanish language (https://uio.instructure.com/courses/35550). This paper shows how this grammar uses Canvas in very specific ways to explore new uses for the platform. It is also explained the goals, didactics and key choices made during the collaborative process that led to accomplish successfully the project. In addition, it is also shown how this activity was integrated as a course into the Spanish curricula and it challenges the traditional student-instructor role in order to offer the students relevant professional skills for the current job market

Choroidal and retinal structural, cellular and vascular changes in a rat model of Type 2 diabetes

Increasing evidence points to inflammation as a key factor in the pathogenesis of diabetic retinopathy (DR). Choroidal changes in diabetes have been reported and several attempts were made to validate in vivo choroidal thickness (CT) as a marker of retinopathy. We aimed to study choroidal and retinal changes associated with retinopathy in an animal model of spontaneous Type 2 diabetes, Goto-Kakizaki (GK) rats. Sclerochoroidal whole mounts and cryosections were prepared from 52-week-old GK and age-matched control Wistar Han rats. CT was measured by optical coherence tomography. Microglia reactivity, pericyte and endothelial cells distribution, and immunoreactivity of vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) were evaluated by immunofluorescence. Choroidal vessels were visualized by direct perfusion with 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (Dil). Choroidal vascular density was evaluated by fluorescence microscopy. GK rats had increased CT (58.40 ± 1.15 μm versus 50.90 ± 1.58 μm, p < 0.001), reduced vascular density of the choriocapillaris (CC) (p = 0.045), increased Iba1+ cells density in the outer retina (p = 0.003) and increased VEGFR2 immunoreactivity in most retinal layers (p = 0.021 to 0.037). Choroidal microglial cells and pericytes showed polarity in their distribution, sparing the innermost choroid. This cell-free gap in the inner choroid was more pronounced in GK rats. In summary, GK rats have increased CT with decreased vascular density in the innermost choroid, increased VEGFR2 immunoreactivity in the retina and increased Iba1+ cells density in the outer retina.info:eu-repo/semantics/publishedVersio

References data on the growth and population parameters of brown trout in siliceous rivers of Galicia (NW Spain)

Brown trout is an important angling species worldwide, and its morphology, population structure and genetics can be highly variable from one location to another. In this study, we provide data for the establishment of reference range values for several population and growth parameters of brown trout in the Cantabrian-Atlantic siliceous rivers of Galicia (NW Spain). Additionally, this study tests the hypothesis that the population and growth parameters differ among sections of rivers with different exploitation statuses (unexploited, exploited-regulated and exploited-open sections). Our study revealed that such population parameters as biomass and production were higher in unexploited sections, but the differences in growth among the sections with different angling regulations were not consistent. The findings of this study are discussed in light of the present knowledge on the status of trout fisheries, as it is essential for the development of management plans. Additional studies are needed to clarify whether the differences in growth can be correlated to the angling regulations.La trucha común es una especie muy apreciada por los pescadores deportivos en todo el mundo, y su morfología, estructura poblacional y características genéticas pueden variar considerablemente entre áreas geográficas próximas. En este estudio proporcionamos datos para el establecimiento de categorías de referencia de varios parámetros poblacionales y de crecimiento de la trucha común en ríos silíceos Cantábrico-Atlánticos de Galicia (NO España). Además, con la realización de este estudio se pretende verificar la hipótesis de que los parámetros poblacionales y el crecimiento pueden variar entre tramos de ríos con diferente tipo de regulación de pesca deportiva (tramos vedados o inexplotados, tramos de pesca acotados y tramos de pesca libre). Así, nuestro estudio reveló que algunos parámetros poblacionales como la biomasa y la producción fueron más elevados en los tramos vedados, pero las diferencias en el crecimiento entre tramos con diferente regulación de pesca deportiva no fueron consistentes. Los resultados de este trabajo se discuten teniendo en cuenta el conocimiento actual sobre el estado de las poblaciones de trucha común, pues son esenciales para el desarrollo de planes de gestión. No obstante, se requieren de más estudios para aclarar si las diferencias en crecimiento se pueden relacionar con el tipo de regulación de pesca deportiva