Origami constraints on the initial-conditions arrangement of dark-matter caustics and streams

In a cold-dark-matter universe, cosmological structure formation proceeds in rough analogy to origami folding. Dark matter occupies a three-dimensional 'sheet' of free- fall observers, non-intersecting in six-dimensional velocity-position phase space. At early times, the sheet was flat like an origami sheet, i.e. velocities were essentially zero, but as time passes, the sheet folds up to form cosmic structure. The present paper further illustrates this analogy, and clarifies a Lagrangian definition of caustics and streams: caustics are two-dimensional surfaces in this initial sheet along which it folds, tessellating Lagrangian space into a set of three-dimensional regions, i.e. streams. The main scientific result of the paper is that streams may be colored by only two colors, with no two neighbouring streams (i.e. streams on either side of a caustic surface) colored the same. The two colors correspond to positive and negative parities of local Lagrangian volumes. This is a severe restriction on the connectivity and therefore arrangement of streams in Lagrangian space, since arbitrarily many colors can be necessary to color a general arrangement of three-dimensional regions. This stream two-colorability has consequences from graph theory, which we explain. Then, using N-body simulations, we test how these caustics correspond in Lagrangian space to the boundaries of haloes, filaments and walls. We also test how well outer caustics correspond to a Zel'dovich-approximation prediction.Comment: Clarifications and slight changes to match version accepted to MNRAS. 9 pages, 5 figure

Experimental Stark widths and shifts of V II spectral lines

We have measured the Stark widths and shifts of V II spectral lines in the wavelength range 2000-4200 Å belonging to 75 multiplets. The spectra are emitted by laser-induced plasmas generated from fused glass discs prepared by borate fusion. The electron density and temperature are in the ranges (0.72-6.5) × 1017 cm-3 and (11 000-14 900) K, respectively. To avoid self-absorption, we have used seven samples with vanadium concentrations selected by the CSigma graph methodology. This has allowed to include strong and weak lines in the study, including resonance and forbidden lines. The experimental widths and shifts are compared with theoretical values available in the literature.Fil: Manrique Rosel, Javier. Universidad CEU San Pablo; EspañaFil: Diaz Pace, Diego Martin. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; ArgentinaFil: Aragón, Concepción. Universidad Publica de Navarra. Departamento de Ciencias.; EspañaFil: Aguilera Andoaga, Jose antonio. Universidad Publica de Navarra. Departamento de Ciencias.; Españ

Dibujos animados en la enseñanza

We present some reflections about using cartoons as an innovative tool for teaching science, as well as for contributing to the practice by teacher researchers. These ideas were part of the results obtained in the seminar "Cartoons", offered by the research group “learning and teaching physics”, into the 1st festival of art and science for coexistence, held in Maloka, Bogotá, 2009. We analyzed the particular case for physics teaching based on cartoons, thinking about what that's means in didactic of physics.En este escrito se presentan algunas de las reflexiones acerca del uso de los dibujos animados como una herramienta innovadora para la enseñanza ciencias, y sobre el ejercicio del docente como investigador, que hacen parte de los resultados que se obtuvieron en el seminario “Dibujos animados” que el grupo de investigación “Enseñanza y Aprendizaje de la Física” desarrolló en el primer Festival de Arte y Ciencia para la Convivencia, realizado por Maloka en Bogotá, 2009. Analizamos el caso particular de la enseñanza de la física a partir de los dibujos animados y su significado en la didáctica de la física

The role of cation chloride co-transporters (CCCs) as potential neuroprotective targets in ischaemic stroke

Stroke is one of the major causes of death and disability worldwide. The area that surrounds the infarcted core is the location of the continuing damage that takes place hours and days following an insult, and is referred to as the penumbra. By creating an oxygen deprived environment in the neuronal-like PC12 and NT2 cells and an in vivo photothrombotic model of stroke (PTS) in mice, two different strategies were created to replicate the conditions of an ischaemic brain.In differentiated PC12 and NT2 cells, following hypoxia, preferential activation of HIF-2α transcription and protein expression was detected. Increased expression of the neural progenitor stem cell-like markers, thought to be transcriptionally regulated by HIF-2α, were also observed. Furthermore, hypoxia caused loss of neuronal characteristics in differentiated cells. This is highly significant as it shows neuronal cells possess molecular mechanisms which could trigger recovery following ischaemic insult.The expression of the chloride co-transporters, NKCC1 and KCC2, mediators of the GABAergic response, was assessed following hypoxia in differentiated PC12 and NT2 cells and PTS. In PC12 and NT2 cells exposed to hypoxia, the expression of KCC2 was significantly decreased at both the transcript and protein level whereas NKCC1 expression remained unmodified. In the in vivo model, the development of the penumbra in the days following injury was assessed with specific markers allowing the identification of the penumbra up to 200 ❍m from the ischaemic core and a progressive neuronal loss was observed within. Our results show an increase in the number of neurons expressing NKCC1 in the penumbra up to 5 days following the insult when compared to the contralateral hemisphere. On the contrary, KCC2 positive cells were dramatically decreased in this area. In mice treated with bumetanide, an NKCC1 antagonist, a significant reduction in neuronal loss was observed. Our results show a reversal on the chloride co-transporters expression in vitro and in vivo and how treatments targeting these channels might represent a novel strategy to reduce the damage associated with stroke

Pierre Bourdieu and Surveys in Sociology of Education

El artículo tiene como propósito ayudar a imaginar y comprender el espíritu con el que Pierre Bourdieu y el grupo de investigadoras e investigadores que animaba concibieron, a principios de la década de 1960, sus primeras investigaciones y encuestas sobre los estudiantes y el sistema educativo. Evoca las investigaciones y encuestas dirigidas por Pierre Bourdieu que nutrieron y originaron muchos otros trabajos, como los de opinión política, sobre profesores universitarios o sobre el campo del poder. Se centra particularmente en las investigaciones y encuestas de la década de 1960, destaca el impulso que mayo de 1968 aportó a las investigaciones en educación, para luego abundar en la investigación emprendida en 1969 sobre los factores de cambio y las fuerzas de inercia en el sistema escolar. Explica que fue imperativo centrarse no sólo en el peso de la reproducción en el sistema educativo, sino también en las transformaciones que se estaban produciendo en la universidad, en el sistema educativo en general e, incluso, en toda la sociedad. En su conjunto, el artículo es un invaluable testimonio, sólidamente documentado, que permite comprender el papel central de la sociología de la educación y la cultura en el trabajo sociológico de Pierre Bourdieu.The purpose of this article is to help to imagine and understand the spirit in which Pierre Bourdieu and the group of researchers he led conceived, in the early 1960s, their first research and surveys on students and the educational system. It evokes the research and surveys conducted by Pierre Bourdieu that nurtured and originated many other works, such as those on political opinion, on university professors or on the field of power. He focuses particularly on the research and surveys of the 1960s, highlights the impetus that May 1968 brought to research in education, and then elaborates on the research undertaken in 1969 on the factors of change and the forces of inertia in the school system. He explains that it was imperative to focus not only on the weight of reproduction in the educational system, but also on the transformations that were taking place in the university, in the educational system in general, and even in a society as a whole. Taken as a whole, the article is an invaluable, solidly documented testimony that allows us to understand the central role of the sociology of education and culture in Pierre Bourdieu’s sociological work

Causal Attribution for Poverty in Young People: Sociodemographic Characteristics, Religious and Political Beliefs

Poverty is a multidimensional phenomenon that includes a lack of education, health or housing; it is a relevant factor of social vulnerability that could lead to a situation of social exclusion. According to studies, poverty can be explained by external/social, internal/individual or cultural fatalistic factors. The aim was to confirm the structure of causal attributions of poverty and their relationships with sociodemographic characteristics, as well as religious and political beliefs, in young people. This is a cross-sectional study with a non-probabilistic convenience sample of undergraduate students on different degree courses. A survey was administered to 278 participants (45.4% women) with an average age of 21.59. They were young people studying health science degrees (78.4%) who self-identified as belonging to the lower or middle–lower class (57.2%), without any religious beliefs (56.5%) and as left wing (37.8%; n = 94) or center-left (27.7%; n = 69) in their political orientation. Confirmatory factorial analysis and multiple regression analysis supported the results in previous literature (CFI = 0.90, SRMR = 0.07, RMSEA = 0.06), indicating that there are cultural (C), external (E-S) and internal (I) attribution factors of poverty. The results show moderate relationships between the cultural factor and internal or external factors. The findings show that political affiliation and sex are the most consistent predictors of attributions for poverty.The APC was funded by Miguel Hernández University (Open access publishing grants (OPEN ACCESS)

En el processo de la ocupacion de las partidas del indio por el illustrissimo Reyno de Aragon : contra Pedro Martin de Borao y Josef Borao

Copia digital : Diputación Provincial de Zaragoza. Servicio de Archivos y Bibliotecas, 2010Ejemplar sin portada, datos de tít. tomados de p.1Sin pie de imprenta, al final del texto aparece fecha de 1650Sign.: A\p8\sInic. grab. xil

The sensitivity of hospital coding to prices : evidence from Indonesia

This study examines a newly introduced DRG system in Indonesia. We use secondary data for 2015 and 2017 from Jaminan Kesehatan Nasional (JKN), a patient level dataset for Indonesia created in 2014 to record public and private hospitals' claims to the national health insurance system to investigate whether there is an association between changes in tariffs paid and the severity of inpatient activity recorded in hospitals. We find a consistent small, positive and statistically significant correlation between changes in tariffs and changes in concentration of activity, indicating discretionary but limited coding behaviour by hospitals. The results indicate that reducing price differentials may mitigate discretionary coding, but that the benefits of this are limited and need to be compared to the potential risk of having to rebase all prices upwards

Successful pacing profiles of Olympic and IAAF World Championship middle-distance runners across qualifying rounds and finals

Purpose: This was the first study to analyze high-resolution pacing data from multiple global championships, allowing for deeper and rigorous analysis of pacing and tactical profiles in elite-standard middle-distance racing. The aim of this study was to analyze successful and unsuccessful middle-distance pacing profiles and variability across qualifying rounds and finals. Methods: Finishing and 100-m split speeds and season’s best times (SB) were collected for 265 men and 218 women competing in 800 m and 1500 m races, with pace variability expressed using coefficient of variation (CV). Results: In both events, successful athletes generally separated themselves from slower athletes in the final 200 m, not by speeding up, but by avoiding slowing compared with competitors. This was despite different pacing profiles between events in the earlier part of the race preceding the endspurt. Approximately 10% of athletes ran SBs, showing a tactical approach to elite-standard middle-distance racing, and possible fatigue across rounds. Men’s and women’s pacing profiles were remarkably similar within each event, but the previously undescribed seahorse-shaped profile in the 800 m (predominantly positive pacing) differed from the J-shaped negative pacing of the 1500 m. Pacing variability was high compared with world records, especially in the finals (CV: 5.2 – 9.1%), showing that athletes need to be able to vary pace and cope with surges. Conclusions: Previous studies have focussed more on athletes in finals, but the present study showed that the best athletes had the physiological capacity to vary pace and respond to surges through successive competition rounds