Assessment of left ventricle dynamic from cardiac magnetic resonance imaging by means a correspondence approach

In this research, an approach to assess the heart dynamics is reported. The cardiac magnetic resonance images are considered for assessing the left ventricle motion and deformation. The shape of the cavity is obtained by means a segmentation procedure based on a clustering algorithm at an initial instant. This three-dimensional structure is used to establish a region of interest around the border of the structure. An optical flow method allows determining the displacement vector of this region and then defining the shapes of the cavity during the all cardiac cycle. The points of the left ventricle are followed using the displacement vectors in the cardiac cycle, obtaining thus, a dense motion field of the cavity. This approximate deformation field is refined with a correspondence method that working in the three-dimensional space. The mapping of the points that define the left ventricle in the cardiac cycle obtained with the correspondence procedure are then used for computing a set of clinical parameters that allows assessing the motion and deformation of this principal structure of the human heart. The torsion, radial and longitudinal contraction are quantified. The obtained results are promising for evaluating the heart dynamics

Effects of grade retention policies: a literature review of empirical studies applying causal inference

The identification of the causal effects of grade retention policies is of enormous relevance for researchers and policymakers alike. Taking advantage of the availability of more detailed longitudinal datasets, researchers have been able to apply different identification strategies that address the classical problems of selection bias and unobserved heterogeneity that have plagued previous studies on the effect of retention. We present a systematic literature review of empirical studies aiming to unveil the causal effects of retention. This study underlines the need to consider and evaluate different kinds of grade retention polices as their effects vary depending on several dimensions (such as timing of the policy, comparison groups, length of the effects or institutional settings). According to the results of our review, we conclude that grade retention is unlikely to be an efficient policy as the costs associated to the policy can easily outweigh the potential (weak) benefits of retention. It is therefore necessary to consider alternative policies to retention, or policies that can be used in combination with it, in order to enhance the performance of low achievers, in particular those students at risk characterized by a low ability profile

La raza sayaguesa base de la marca silomaña. Actualidad y posibilidades

La utilización de los pastos de la montaña de León unido a una raza autóctona, la raza sayaguesa, para la obtención de un producto de calidad y diferenciado como es el buey. Nos ha permitido obtener un producto de unas características hasta ahora desconocidas, con un perfil de ácidos grasos mono y poliinsaturados, y unas características físico-químicas que hacen que nuestro producto puede considerarse como un “ALIMENTO FUNCIONAL”

Treinta y cinco años de investigación en gestión estratégica. Un análisis de países utilizando técnicas bibliométricas para el período 1987-2021

[EN] As a significant field of study, thirty-five years of strategic management research has accumulated a substantial amount of knowledge. This bibliometric study explores whether the unlimited flow of knowledge and the globalization of education & research in this time period, could drive away (or deter) the identification and specific interest of research in phenomena of national importance. Using bibliometric techniques and visualization of similarities (VOS) procedures of citation and co-citation analyses, this Paper explores research trends at the country level over 35 years using data from the Web of Science database. The aims are to identify: 1) the most visible and prominent actors at the country, regional, and global-level; 2) the evolution of the subjects of research into strategic management at the country, global, and supra-regional level; and 3) the evolution of journals publishing strategic management research articles by location. Findings suggest that common research subjects coexist at higher levels of aggregation, establishing the “paradigm” or general agreement about the field’s boundaries. Additionally, findings show that at the country level, rather than following a global trend, there is an enduring diversification of research agendas that bow to national and supranational factors from geographically close places.[ES] Como un campo de estudio importante, treinta y cinco años deinvestigación en gestión estratégica han acumulado una cantidad sustancial deconocimiento. Este estudio bibliométrico explora si el flujo ilimitado deconocimiento y la globalización de la educación y la investigación en esteperíodo de tiempo, podría alejar (o disuadir) la identificación y el interésespecífico de investigación de fenómenos de importancia nacional. Utilizandotécnicas bibliométricas y procedimientos de visualización de similitudes (VOS) de análisis de citas y co-citas, este documentoexplora las tendencias de investigación a nivel de país durante 35 añosutilizando datos de la base de datos Web of Science. Los objetivos se centranen identificar: 1) los actores más visibles y destacados a nivel nacional,regional y mundial; 2) la evolución de los temas de investigación de la gestiónestratégica a nivel país, global y suprarregional; y 3) la evolución de las revistas que publicanartículos de investigación de gestión estratégica por ubicación. Los hallazgossugieren que los temas de investigación comunes coexisten en niveles superioresde agregación, estableciendo el “paradigma” o acuerdo general sobre los límitesde campo de estudio. Además, los hallazgos muestran que, a nivel de países,existe una diversificación persistente de agendas de investigación, que seinclinan a estudiar eventos nacionales y supranacionales de lugaresgeográficamente cercanos, en vez de seguir una tendencia global

Uncertainty as key element in the analysis of X–ray angiography images

The X–ray angiography images are routinely used to assess the blood vessels. The acquisition procedure considers a medical imaging system which allows obtaining views of the vessel while the blood flows thought them. The X–ray source is influenced on the region to be viewed and then, the projection of the all anatomical structures in the champ of view is shown through an image intensifier. The information of the blood vessel is impacted for the other structures. Additionally, the blood and the contrast product required in the acquisition are not mixed homogeneously, producing artifacts in the images. Finally, the noise is also an impact factor in the quality of the angiography images. In the coronary vessel case, the branches of the network are superposed. In this paper, an enhancement procedure to diminish the uncertainty associated to X–ray angiography images is reported. The relation between two versions of the angiograms is determined using a fuzzy connector considering that this relation diminishes the images intrinsic uncertainty. These versions correspond with images filtered with low-pass and high-pass image filters, respectively. The technique is tested with images of the coronary and kidney vessels. The qualitative results show a good enhanced of the angiography images

Construcción del conocimiento didáctico del contenido biológico en formación inicial de profesores

Presentamos la sistematización de los datos obtenidos a partir de los documentos que presentaron dos grupos de futuros profesores de Biología, a lo largo de un semestre, al diseñar Unidades Didácticas para la enseñanza de dos temáticas relacionadas con el auto-mantenimiento de los organismos. Analizamos los referentes de los docentes en formación acerca del Conocimiento Didáctico del Contenido Biológico (contemplamos 9 categorías de investigación) y los cambios de los mismos durante el proceso formativo en el que los estudiantes-profesores realizaron la propuesta

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

Electronic structure of titanylphthalocyanine layers on Ag(111)

We have investigated the electronic structures of axially oxo functionalized titanylphthalocyanine (TiOPc) on Ag(111) by X-ray and ultraviolet photoelectron spectroscopies, two-photon photoemission, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. Furthermore, we use complementary data of TiOPc on graphite and planar copper phthalocyanine (CuPc) on Ag(111) for a comparative analysis. Both molecules adsorb on Ag(111) in a parallel orientation to the surface, for TiOPc with an oxygen-up configuration. The interaction of nitrogen and carbon atoms with the substrate is similar for both molecules, while the bonding of the titanium atom to Ag(111) in the monolayer is found to be slightly more pronounced than in the CuPc case. Ultraviolet photoemission spectroscopy reveals an occupation of the lowest unoccupied molecular orbital (LUMO) level in monolayer thick TiOPc on Ag(111) related to the interaction of the molecules and the silver substrate. This molecule-metal interaction also causes an upward shift of the Ag(111) Shockley state that is transformed into an unoccupied interface state with energies of 0.23 and 0.33 eV for the TiOPc monolayer and bilayer, respectively, at the Brillouin zone center.The authors acknowledge financial support from the Deutsche Forschungsgemeinschaft through SFB 1083 “Structure and Dynamics of Internal Interfaces”, the Spanish CSIC I-Link programm, the Spanish Ministry of Economy and Competitiveness, MINECO (under Contract No. MAT2016-78293-C6-2-R, and Severo Ochoa No. SEV-2013-0295.), and by the Secretariat for Universities and Research, Knowledge Department of the Generalitat de Catalunya (2014 SGR 715). M. Paradinas thanks the Spanish Government for financial support through PTA2014-09788-I fellowships. ICN2 is funded by the CERCA Programme/Generalitat de Catalunya.Peer Reviewe

Electronic Structure of Titanylphthalocyanine Layers on Ag(111)

We have investigated the electronic structures of axially oxo functionalized titanylphthalocyanine (TiOPc) on Ag(111) by X-ray and ultraviolet photoelectron spectroscopies, two-photon photoemission, X-ray absorption spectroscopy, and X-ray magnetic circular dichroism. Furthermore, we use complementary data of TiOPc on graphite and planar copper phthalocyanine (CuPc) on Ag(111) for a comparative analysis. Both molecules adsorb on Ag(111) in a parallel orientation to the surface, for TiOPc with an oxygen-up configuration. The interaction of nitrogen and carbon atoms with the substrate is similar for both molecules, while the bonding of the titanium atom to Ag(111) in the monolayer is found to be slightly more pronounced than in the CuPc case. Ultraviolet photoemission spectroscopy reveals an occupation of the lowest unoccupied molecular orbital (LUMO) level in monolayer thick TiOPc on Ag(111) related to the interaction of the molecules and the silver substrate. This molecule-metal interaction also causes an upward shift of the Ag(111) Shockley state that is transformed into an unoccupied interface state with energies of 0.23 and 0.33 eV for the TiOPc monolayer and bilayer, respectively, at the Brillouin zone center

Biomass in crop-livestock systems in the context of the livestock revolution

Mixed crop-livestock systems are the dominant source of livelihood supporting more than 80% of people living in the developing world and producing 50% of world cereals, around 34% of the global beef production and about 30% of global milk production. However, mixed systems are coming under increasing pressure with their human population predicted to increase from 1,099 million in 2000 to 1,670 million people in 2030 and their cattle population to increase from 230 million to 317 million from 2000 to 2030. Coupled with this increase in human and livestock populations, cereal yields have been stagnating in sub-Saharan Africa (SSA) for the last 40 years (in contrast to growth rates of 1.5-2% per year for the rest of the developing world), with most increase in overall cereal production arising from expansion of arable land. Such trends cannot be maintained as land suitable for cropping is scarce, and additional cropland might also be more marginal and subject to greater climatic risks. There is increasing pressure on biomass in mixed systems and there are strong needs to find ways out of this ‘‘biomass trap’’ through increasing overall biomass yield and fodder quality and through increasing the efficiency of livestock production. Biomass from crop residues (CR) is used as a feed resource and as mulch to improve crop yields. Biomass is becoming scarcer and competition for CR is becoming more severe. This is reflected in changes of CR use from grazing to harvesting and storage, longer distances across which CR are transported and transacted and decreasing CR to grain ratios. The predicted increase in demand for livestock products, the so-called livestock revolution, will further fuel feed demand and increase the usage of CR for livestock feeding. Use of CR for mulch and conservation agriculture demands about 2 to 3 tons of CR per hectare which is often equal to their total yield under rain-fed conditions in the semi-arid tropics. Multidimensional crop improvement can mitigate competition for biomass by increasing CR quantity and by improving fodder quality. Increased CR yield will facilitate partitioning of CR between livestock and soil improvement and improved CR fodder quality will support intensification of livestock production where more animal sourced foods (ASF) can be produced with less feed. It is important to realize that feed biomass requirement is very context specific and decreases with increasing per unit animal productivit