3,730 research outputs found
Rational approximations of cosmography through Pad\'e polynomials
We consider high-redshift cosmography adopting the technique of
polynomial reconstruction. In lieu of considering Taylor treatments, which turn
out to be non-predictive as soon as , we take into account the Pad\'e
rational approximations which consist in performing expansions converging at
high redshift domains. Particularly, our strategy is to reconstruct
functions first, assuming the Ricci scalar to be invertible with respect to the
redshift . Having the thus-obtained functions, we invert them and we
easily obtain the corresponding terms. We minimize error propagation,
assuming no errors upon redshift data. The treatment we follow naturally leads
to evaluating curvature pressure, density and equation of state, characterizing
the universe evolution at redshift much higher than standard cosmographic
approaches. We therefore match these outcomes with small redshift constraints
got by framing the cosmology through Taylor series around .
This gives rise to a calibration procedure with small redshift that enables the
definitions of polynomial approximations up to . Last but not
least, we show discrepancies with the standard cosmological model which go
towards an extension of the CDM paradigm, indicating an effective dark
energy term evolving in time. We finally describe the evolution of our
effective dark energy term by means of basic techniques of data mining.Comment: 11 pages, 14 figures, accepted for publication in JCA
Los Centros Cimarrones, estrategia pedagoÌgica de revitalizacioÌn poliÌtico-identitaria del pueblo afroecuatoriano
En el texto final de la uÌltima Conferencia General del Episcopado Latinoamericano realizada en Aparecida en el 2007, se lee lo siguiente: âLa historia de los afroamericanos ha sido atravesada por una exclusioÌn social, econoÌmica, poliÌtica y, sobre todo, racial, donde la identidad eÌtnica es factor de subordinacioÌn social. Actualmente, son discriminados en la insercioÌn laboral, en la calidad y contenido de la formacioÌn escolar, en las relaciones cotidianas y ademaÌs existe un proceso de ocultamiento sistemaÌtico de sus valores, historia, cultura y expresiones religiosas...de modo que, descolonizar las mentes, el conocimiento, recuperar la memoria histoÌrica, fortalecer espacios y relaciones interculturales, son condiciones para la afirmacioÌn de la plena ciudadaniÌa de estos pueblosâ (Aparecida, 2007: n. 96)
Conceptos y reflexiones para la conciencia cimarrona
La historia nos demuestra que los que tienen sed de conquista, al invadir un territorio y su gente, lo primero que hacen es descalificar el universo cultural del âotroâ para asiÌ imponer su proyecto hegemoÌnico.
En AmeÌrica Latina, con la conquista espanÌola primero y con la creacioÌn del Estado-nacioÌn despueÌs, se ha venido impulsando, hasta nuestros diÌas, la construccioÌn de un universo simboÌlico predominantemente blanco-mestizo, y se ha promovido un discurso homogeneizador de pertenencia nacional, obligando a todo el mundo a reconocerse parte de una misma realidad cultural
Social media implementation in higher education institutions between mimicry and professionalism
NPOs and private governance forms for football clubs: towards a blended model
PurposeThis study explores the relationship between governance model - private organisations vs non-profit organisations (NPOs) - and performance in football clubs.Design/methodology/approachThe study is a comparative case study of two football clubs with different governance models: Malmo FF, which is an NPO, and Bologna FC, which is a privately owned club.FindingsThe results show that both football clubs focus equally on financial and non-financial performance, and in practice, both clubs use a blend of private and NPO governance models. While supporting efforts towards financial results, blending the models appears to support football clubs' management of the tension between financial and non-financial performance and the expectation that they will contribute to local development. Thus, using a blend of the two models is not only accepted but expected.Research limitations/implicationsThis study is a comparative case study of two football clubs. This study furthers our understanding of how football clubs manage the tension between financial and non-financial performance expectations. This is particularly of interest in light of the increasing professionalisation of sports, especially football, and how this might jeopardise the contributions that sport clubs make to the local community.Originality/valueBy exploring the relationship between governance model and performance, this study shows that, contrary to expectations, privately owned football clubs focus as much on non-financial performance as clubs governed as NPOs. This study contributes to the existing literature by showing how clubs use a mixture of elements from governance models to manage the tension between financial and non-financial performance that has emerged in the wake of the increasing professionalisation of football
Damaging micromechanisms in an as cast ferritic and a ferritized ductile cast iron
Mechanical behavior and damaging micromechanisms in Ductile Cast Irons (DCIs) are strongly effected by matrix microstructure (e.g., phases volume fraction, grains size and grain distribution) and graphite nodules morphology peculiarities (e.g., nodularity level, nodule size, nodule count, etc.). The influence of the graphite nodules depends on both the matrix microstructure and the loading conditions (e.g., quasi-static, dynamic or cyclic loadings). According to the most recent results, these graphite nodules show a mechanical properties gradient inside the graphite nodules, with the graphite elements â matrix debonding as only one of the possible damaging micromechanisms. In this work, two different ferritic DCIs were investigated (a ferritic matrix obtained from as-cast condition and a ferritized matrix) focusing on the damaging micromechanisms in graphite nodules due to tensile stress. Specimens lateral surfaces were observed using a Scanning Electron Microscope (SEM) during the tests following a step by step procedure.Fil: D' Agostino, Laura. UniversitĂ di Cassino e del Lazio Meridionale; ItaliaFil: Di Cocco, Vittorio. UniversitĂ di Cassino e del Lazio Meridionale; ItaliaFil: Fernandino, Diego Omar. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Mar del Plata. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales. Universidad Nacional de Mar del Plata. Facultad de IngenierĂa. Instituto de Investigaciones en Ciencia y TecnologĂa de Materiales; ArgentinaFil: Lacoviello, Francesco. UniversitĂ di Cassino e del Lazio Meridionale; Itali
Evidence on the Bidirectional Relationship Between Health and Life Satisfaction in Older Adults
AbstractPrevious research on health and life satisfaction in older adults has suggested a bidirectional relationship. However, most evidence either is based on cross-sectional data, being unsuitable for inferring any directionality on the results, or disregards the within-person stability of both variables over time, thus providing potentially biased results. We analysed data from 11,667 older adults interviewed between 2008 and 2016 within the English Longitudinal Study of Ageing. A health measure including self-reported and measured tests on cognitive and physical performance was computed using a Bayesian multilevel item-response theory approach. Life satisfaction was assessed with the Satisfaction with Life Scale. Cross-lagged models using a Structural Equation Modelling approach were used to analyse the longitudinal interrelation between health and life satisfaction. Models accounting and not accounting for the within-person stability in the measures were computed. Additional sensitivity models were ran using an exclusively self-reported measure of health. Health and life satisfaction were significant longitudinal predictors of one another only when the within-person stability was not considered. The effect of life satisfaction on health became negligible once that stability was modelled. The impact of not accounting for within-person stability was larger when health was measured exclusively with self-reported information. Our study suggests that health and life satisfaction are not bidirectionally related in older adults, but only health predicts a better life satisfaction over time. Thus, policies aimed at fostering older adultsâ life satisfaction by focusing on health enhancement and maintenance may be fruitful, whereas the opposite may not.</jats:p
Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps
Abstract. Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy). Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface
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