Search results for "Homogeneous"
showing 10 items of 718 documents
Development of accelerometer-based light to vigorous physical activity in fitness profiles of school-aged children.
2021
This study examined the developmental trajectories of light (LPA) and moderate-to-vigorous physical activity (MVPA) in fitness profiles derived from motor competence, perceived motor competence, health-related fitness, and MVPA behaviour. Locomotor, stability, and object-control skills, muscular and cardiovascular fitness, and physical activity were assessed in 510 (girls 285, boys 225) Finnish school-aged children (Mage = 11.26 ± .33 years) over three years. Physical activity was measured using hip-mounted accelerometers. Fitness profiles were identified using latent profile analysis and the development of physical activity levels across four assessments was analysed with latent growth cur…
Modeling Return to Education in Heterogeneous Populations: An Application to Italy
2019
The Mincer human capital earnings function is a regression model that relates individual’s earnings to schooling and experience. It has been used to explain individual behavior with respect to educational choices and to indicate productivity on a large number of countries and across many different demographic groups. However, recent empirical studies have shown that often the population of interest embed latent homogeneous subpopulations, with different returns to education across subpopulations, rendering a single Mincer’s regression inadequate. Moreover, whatever (concomitant) information is available about the nature of such a heterogeneity, it should be incorporated in an appropriate ma…
Relaxion fluctuations (self-stopping relaxion) and overview of relaxion stopping mechanisms
2020
Journal of high energy physics 2005(5), 80 (2020). doi:10.1007/JHEP05(2020)080
Marx y Engels y la división sexual del trabajo en la familia: ambigüedades, equívocos y vacíos teóricos
2018
Dada la importante influencia de Marx y Engels en el análisis de la estructura social, no sorprende el notable impacto de su obra en el estudio del papel de la mujer en la familia. Sin embargo, su herencia en este ámbito sociológico ha dado lugar a interpretaciones muy polarizadas. Este artículo quiere aportar algo de luz evidenciando las contradicciones del marxismo al estudiar el papel de la mujer en la familia. Para ello se comparan las contribuciones de Marx y Engels para calibrar posibles diferencias en las posturas de dos autores que en otros ámbitos han presentado un pensamiento muy homogéneo. Los resultados obtenidos permiten afirmar que, a pesar de su innegable influencia en el pen…
Preliminary Experimental Study on Double Fuel HCCI Combustion
2015
AbstractThis paper regards an experimental study on a particular internal combustion engine process which combines Double Fuel combustion with Homogeneous Charge Compression Ignition (HCCI) using mixtures of natural gas (NG) and gasoline. The tests performed on a CFR engine demonstrate that HCCI combustion can be achieved using NG-gasoline mixtures without knocking occurrence for low to medium engine load varying the proportion between the two fuels. The main advantage of this new combustion process relies on the noticeable higher engine efficiency obtained with respect to conventional spark ignition operation, and on the strong reduction of NOX emissions.
Kompleksy metali przejściowych z zasadami Lewisa jako prekursory katalizatorów polimeryzacji olefin. Cz. I. Postęp w komputerowym modelowaniu procesu…
2001
A review with 35 references covering molecular modeling in coordination polymerization over homogeneous and heterogeneous Ziegler-Natta catalysts. The study includes supports, cocatalysts, Lewis bases and solvents. Recent progress in elucidating the mechanisrn of elementary polymerization steps is presented against the background of rapidly deveIoping computational methods and available computational power. Theoretical studies on polymerization mcchanisms and structure of active centers are described (egns. 1-4). Authors own calculations are used to compare [MtC14(THF)2] complex-based (Mt = Ti, Hf or Zr) heterogeneous catalysts. The geometrical characteristics of precursors is presented (Ta…
homogeneous embeddings of SL2(C) modulo a finite sub-group.
2000
L'objet de ce travail est l'étude des variétés algébriques normales complexes munies d'une action algébrique de $SL_{2}$ et qui contiennent $SL_{2}/H$ comme orbite ouverte, $H$ étant un sous-groupe fini de $SL_{2}$.Plus précisément on définit un plongement homogène de $SL_{2}/H$ comme la donnée d'une $SL_{2}$-variété irréductible $X$ (quasi-projective ou non) contenant $SL_{2}/H$ comme orbite ouverte et d'un morphisme $SL_{2}$-équivariant de $SL_{2}$ dans $X$.Les plongements homogènes lisses ainsi que les plongements minimaux (plongements lisses et complets qui ne sont pas des éclatements d'un autre plongement lisse complet) de $SL_{2}/\{Id\}$ et de $SL_{2}/\{\pm Id\}$ ont été déterminés pa…
Heat wave occurrences over Senegal during spring: regionalization and synoptic patterns.
2020
18 pages; International audience; Based on 12 Senegalese stations of the Global Summary of the Day (GSOD) database (1979–2014), heat waves (HW) are defined for each station in spring (March–April–May, the hottest season in Senegal) as the daily maximum temperature (Tx), minimum temperature (Tn), or average apparent temperature of the day (AT), exceeding the corresponding 95% mobile percentile for at least three consecutive days. A hierarchical cluster analysis used to regionalize HW in these 12 stations is applied to simultaneous occurrences of daily temperature peaks over their 95% mobile percentiles. Three homogeneous zones of four stations each are identified (Zone 1, Zone 2 and Zone 3),…
Organocatalytic approach to benzofused nitrogen-containing heterocycles: enantioselective total synthesis of (+)-angustureine.
2008
Modelling molecular iodine emissions in a coastal marine environment: The link to new particle formation
2006
International audience; A model of iodine chemistry in the marine boundary layer (MBL) has been used to investigate the impact of daytime coastal emissions of molecular iodine (I2). The model contains a full treatment of gas-phase iodine chemistry, combined with a description of the nucleation and growth, by condensation and coagulation, of iodine oxide nano-particles. In-situ measurements of coastal emissions of I2 made by the broadband cavity ring-down spectroscopy (BBCRDS) and inductively coupled plasma-mass spectrometry (ICP/MS) techniques are presented and compared to long path differential optical absorption spectroscopy (DOAS) observations of I2 at Mace Head, Ireland. Simultaneous me…