Validation of microsatellite markers for cytotype discrimination in the model grass Brachypodium distachyon

Brachypodium distachyon (2n = 2x = 10) is a small annual grass species where the existence of three different cytotypes (10, 20 and 30 chromosomes) has long been regarded as a case of autopolyploid series, with x = 5. However, it has been demonstrated that the cytotypes assumed to be polyploids represent two separate Brachypodium species recently named as B. stacei (2n = 2x = 20) and B. hybridum (2n = 4x = 30). The aim of this study was to find a PCR-based alternative approach that could replace standard cytotyping methods (i. e., chromosome counting and flow cytometry) to characterize each of the three Brachypodium species. We have analyzed with four microsatellite (SSR) markers eighty-three Brachypodium distachyon-type lines from varied locations in Spain, including the Balearic and Canary Islands. Within this set of lines, 64, 4 and 15 had 10, 20 and 30 chromosomes, respectively. The surveyed markers produced cytotype-specific SSR profiles. So, a single amplification product was generated in the diploid samples, with non-overlapping allelic ranges between the 2n = 10 and 2n = 20 cytotypes, whereas two bands, one in the size range of each of the diploid cytotypes, were amplified in the 2n = 30 lines. Furthermore, the remarkable size difference obtained with the SSR ALB165 allowed the identification of the Brachypodium species by simple agarose gel electrophoresis

Pressure and velocity distributions in plunge pools

Presented at the Protections 2016: 2nd international seminar on dam protection against overtopping: concrete dams, embankment dams, levees, tailings dams held on 7th-9th September, 2016, at Colorado State University in Fort Collins, Colorado, USA. The increasing demand for dam and levee safety and flood protection has motivated new research and advancements and a greater need for cost-effective measures in overtopping protection as a solution for overtopping concerns at levees and dams. This seminar will bring together leading experts from practice, research, development, and implementation for two days of knowledge exchange followed by a technical tour of the Colorado State University Hydraulic Laboratory with overtopping flume and wave simulator. This seminar will focus on: Critical issues related to levees and dams; New developments and advanced tools; Overtopping protection systems; System design and performance; Applications and innovative solutions; Case histories of overtopping events; Physical modeling techniques and recent studies; and Numerical modeling methods.Includes bibliographical references.When dam overtopping produces rectangular free jets that discharge into plunge pool basins below the dam, the pressure and velocity distributions of the flow in the plunge pool must be estimated to evaluate potential scour that might destabilize the dam. The high turbulence and aeration phenomena that appear in falling jets and dissipation basins make it difficult to carry out studies based only on classical methodologies. This work addresses plunge pool flows, and compares numerical results against our own experiments. Instantaneous pressures, velocities and air entrainment were obtained with the use of piezoresistive transducers, Acoustic Doppler Velocimeter and optical fiber, respectively. Mean velocity field and turbulence kinetic energy profiles were determined. To identify the level of reliability of models, numerical simulations were carried out by using the "homogeneous" model of ANSYS CFX, together with different turbulence closures. The numerical results fall fairly close to the values measured in the laboratory, and with expressions for submerged hydraulic jumps and horizontal wall jets. The observations can be well predicted for horizontal velocities greater than 40% of the maximum velocity in each profile, and when the ratio of the water cushion depth to the jet thickness is lower than 20

Sectorial Economic Growth and Employment in Mexico, 1996-2001

This paper shows the results from a study of the impact of sectorial economic growth on unemployment in Mexico for 1996-2001, by applying a disaggregate approach on data from the National Employment Survey (Encuesta Nacional de Empleo). The paper includes a discussion of the theoretical aspects of the sectorial contributions to growth (emphasizing the case of agriculture), as well as of the relationship between production and employment and the working of labor markets, but also describes the recent evolution of unemployment in Mexico. The core of the paper rests upon the analysis of panel data to estimate the open unemployment rate; it also includes the study of regional urban/rural growth through the analysis of unemployment in different sectors for ten different mexican regions. The results from the estimations at the regional level show that unemployment in Mexico has a statistically significant negative effect on sectorial economic growth. Also, evidence was found suggesting that promoting sectorial-regional (urban/rural) growth is an effective way to reduce unemployment. The paper, which is divided into five sections and draws upon some previous work on Okun’s law, also shows the impact that growth among economic activities within sectors has upon unemployment for the period.Sectorial Growth, Unemployment, Okun’s Law, Panel Data, National Employment Survey

The accretion environment in Vela X-1 during a flaring period using XMM-Newton

We present analysis of 100 ks contiguous XMM-Newton data of the prototypical wind accretor Vela X-1. The observation covered eclipse egress between orbital phases 0.134 and 0.265, during which a giant flare took place, enabling us to study the spectral properties both outside and during the flare. This giant flare with a peak luminosity of $3.92^{+0.42}_{-0.09} \times 10^{37}$ erg s$^{-1}$ allows estimates of the physical parameters of the accreted structure with a mass of $\sim$ $10^{21}$ g. We have been able to model several contributions to the observed spectrum with a phenomenological model formed by three absorbed power laws plus three emission lines. After analysing the variations with orbital phase of the column density of each component, as well as those in the Fe and Ni fluorescence lines, we provide a physical interpretation for each spectral component. Meanwhile, the first two components are two aspects of the principal accretion component from the surface of the neutron star, and the third component seems to be the \textit{X-ray light echo} formed in the stellar wind of the companion.Comment: Accepted. Astronomy and Astrophysics, 201

Convergence of an entropic semi-discretization for nonlinear Fokker-Planck equations in Rd

A nonlinear degenerate Fokker-Planck equation in the whole space is analyzed. The existence of solutions to the corresponding implicit Euler scheme is proved, and it is shown that the semi-discrete solution converges to a solution of the continuous problem. Furthermore, the discrete entropy decays monotonically in time and the solution to the continuous problem is unique. The nonlinearity is assumed to be of porous-medium type. For the (given) potential, either a less than quadratic growth condition at infinity is supposed or the initial datum is assumed to be compactly supported. The existence proof is based on regularization and maximum principle arguments. Upper bounds for the tail behavior in space at infinity are also derived in the at-most-quadratic growth case

Cognitive processes associated with the professional development of the mathematics teacher

This paper proposes a model of professional development based on Sfard’s stages of interiorisation, condensation and reification, which highlights the teacher’s cognitive processes. The model is applied to the case study of a primary teacher participating in a collaborative project for professional development. This adaptation of Sfard’s stages proves to be of special value when interpreting the process of the teacher’s professional development from a cognitive perspective. Procesos cognitivos asociados al desarrollo profesional del profesor de matemáticas Este artículo propone un modelo de desarrollo profesional que pone de relieve los procesos cognitivos del profesor, en relación con las fases de interiorización, condensación y cosificación del trabajo de Sfard. El modelo se aplica al caso de una maestra que participa en un proyecto colaborativo de desarrollo profesional. La adaptación de las fases de Sfard se muestra valiosa para interpretar el proceso de desarrollo profesional de la maestra desde una perspectiva cognitiva. Handle: http://hdl.handle.net/10481/3509Nº de citas en WOS (2017): 1 (Citas de 2º orden, 0)Nº de citas en SCOPUS (2017); 1 (Citas de 2º orden, 1

Un modelo cognitivo para interpretar el desarrollo profesional de los profesores de matemáticas. Ejemplificación en un entorno colaborativo

A partir del trabajo de Sfard en relación con las fases de interiorización, condensación y cosificación para explicar los procesos cognitivos referidos al aprendizaje de las matemáticas, realizamos una propuesta de modelo interpretativo del desarrollo profesional. A continuación, analizamos sus características aplicándolo al caso de una maestra participante en un entorno colaborativo de desarrollo profesional, evidenciando de este modo las potencialidades del modelo.Based on Sfard's stages of interiorisation, condensation and reification, which she applies to explain the cognitive processes in relation to the mathematical learning, we propose an interpretative model of professional development. We analyse its features and then the model is applied to the case study of a primary teacher participating in a collaborative project for professional development. This way we show the model's potentialities

What knowledge and conceptions mobilize future teachers analyzing a classroom video?

El uso del vídeo de sesiones de clase de Educación Primaria (EP) en la formación inicial del maestro aporta realismo a las discusiones teóricas de las aulas de magisterio, contribuyendo a la vinculación entre la teoría y la práctica sobre la base de procesos reflexivos que ayudan a trascender los habituales comentarios genéricos de los estudiantes para maestro (EPM). El objetivo de este estudio es identificar las concepciones sobre la enseñanza y el aprendizaje de las matemáticas así como el conocimiento matemático para la enseñanza (particularmente el conocimiento de matemáticas y la enseñanza y el conocimiento de matemáticas y los estudiantes) que un grupo de EPM pone en juego cuando observa un vídeo de EP. Mediante un diseño de investigación consistente con un experimento de enseñanza (Steffe y Thompson, 2000) (en el que un diseño instruccional, orientado a los EPM, acerca de la introducción del concepto de división, se va refinando a través de sucesivos ciclos de implementación y análisis), se pone de relieve cómo el análisis de situaciones de enseñanza en EP promueve el cuestionamiento de los EPM.The use of the Primary Education (PE) class sessions video in the initial training of teachers provides realism to the theoretical discussions of Master’s degree classrooms, contributing to the link between theory and practice on the basis of reflective processes that help to transcend the normal general comments of teacher students (TS). The objective of this study is to identify the conceptions for the teaching and learning of mathematics, as well as the mathematical knowledge for teaching (particularly the knowledge of mathematics and the teaching and knowledge of mathematics and students) that a group of TS use when observing a PE video. Using a research design consistent with a teaching experiment (Steffe and Thompson, 2000) (in which an instructional design, aimed at TS, regarding the introduction of the concept of division, is refined by means of successive cycles of implementation and analysis), the way the analysis of teaching situations in PE promotes the questioning of TS is highlighted.O uso de vídeos de sessões de aula de Educação Primária (EP) na formação inicial do professor oferece realismo às discussões teóricas sobre as aulas de magistério, contribuindo para a vinculação entre a teoria e a prática sobre a base de processos reflexivos que ajudam a transcender os habituais comentários genéricos dos estudantes para professores (EPM). O objetivo deste estudo é identificar as concepções sobre o ensino e a aprendizagem da matemática, assim como o conhecimento matemático para o ensino (particularmente o conhecimento de matemática e o ensino e o conhecimento de matemática e dos estudantes) que um grupo de EPM põe em jogo quando observa a um vídeo de EP. Através de uma criação de pesquisa consistente com um experimento de ensino (Steffe e Thompson, 2000), destaca-se como a análise de situações de ensino em EP promove o questionamento dos EPM.L’utilisation de la vidéo pour une classe d’élèves en école primaire (EP) durant la formation des futurs instituteurs confère un certain réalisme aux discussions théoriques qui ont lieu dans les cours de formation des instituteurs (l’équivalent en France des IUFM) en contribuant à la création de liens entre théorie et pratique basés sur des processus réflexifs qui permettent aux étudiants d’aller au-delà des habituels commentaires généraux. L’objectif de la présente étude consiste à identifier les conceptions sur l’enseignement et l’apprentissage des mathématiques ainsi qu’à s’interroger sur la connaissance mathématique pour l’enseignement (en particulier, la connaissance des mathématiques et l’enseignement des mathématiques et les étudiants) qu’un groupe de futurs instituteurs utilise lorsqu’il observe une vidéo conçue pour l’école primaire. Grâce à un travail de recherche qui va de pair avec une expérience sur l’enseignement (Steffe et Thompson, 2000) (dans lequel un travail propre à l’enseignement conçu pour les futurs instituteurs portant sur l’introduction du concept de division s’affine de plus en plus au fur et à mesure que des cycles successifs de mises en oeuvre et d’analyse sont utilisés), on montre comment l’analyse de situations en école primaire suscite le questionnement des futurs instituteurs