Search results for "Tributi"
showing 10 items of 6415 documents
Species distributions models may predict accurately future distributions but poorly how distributions change: A critical perspective on model validat…
2023
Aim: Species distribution models (SDMs) are widely used to make predictions on how species distributions may change as a response to climatic change. To assess the reliability of those predictions, they need to be critically validated with respect to what they are used for. While ecologists are typically interested in how and where distributions will change, we argue that SDMs have seldom been evaluated in terms of their capacity to predict such change. Instead, typical retrospective validation methods estimate model's ability to predict to only one static time in future. Here, we apply two validation methods, one that predicts and evaluates a static pattern, while the other measures change…
El "estallido" financiero de 2008 en EEUU: Un análisis institucional de sus principales factores determinantes
2015
El objetivo básico de esta investigación ha sido el analizar lo ocurrido durante los años previos a 2008 en EEUU a efectos de averiguar qué principales factores institucionales, tanto formales como informales, contribuyeron de manera decisiva al estallido de su sistema financiero. Los análisis explicativos elaborados se fundamentan en el denominado enfoque de análisis económico institucional que caracteriza a las aportaciones más recientes elaboradas en la corriente de la Nueva Economía Institucional, en las que ya se presta atención tanto a los aspectos de eficiencia como a los distributivos. El trabajo contiene análisis tanto cualitativos como cuantitativos, con un capítulo final de contr…
Äärellisen väännön kuvaukset : diskreettisyys ja avoimuus
2015
Tämän tutkielman tarkoituksena on tarkastella äärellisen väännön kuvauksia euklidisissa avaruuksissa, erityisesti niiden diskreettisyyttä ja avoimuutta. Äärellisen väännön kuvaukset ovat yleistys kvasisäännöllisistä kuvauksista, jotka molemmat määritellään käyttämällä vääntöepäyhtälöä. Kvasisäännöllisille eli rajoitetun väännön kuvauksille voimassa olevat tulokset jatkuvuudesta, diskreettisyydestä ja avoimuudesta säilyvät myös äärelliseen vääntöön siirryttäessä. Tähän tarvitaan kuitenkin joitain oletuksia kuvauksen vääntöfunktiosta. Työssä konstruoidaan vastaesimerkkejä kuvauksista, joille nämä ominaisuudet eivät välttämättä ole voimassa. Tutkielman päätuloksina osoitetaan, että Sobolev-ava…
Motivation and academic achievement in mathematics: a longitudinal study in the early stages of education
2017
Se analiza longitudinalmente la capacidad predictiva de un conjunto de variables motivacionales sobre el rendimiento matemático. Los análisis se realizan, en una muestra de 180 sujetos, con datos evaluados en dos momentos (Educación Infantil 5 años y 2º curso de Primaria). También se estudian las diferencias entre dos grupos, con rendimiento matemático medio y bajo al finalizar el primer ciclo de Primaria, en las variables motivacionales evaluadas en el primer momento. Los resultados muestran un importante poder predictivo sobre el rendimiento matemático posterior de la competencia percibida. También la persistencia, la actitud y la dimensión atribucional de internalidad positiva aportan un…
Long-term monitoring of the TeV emission from Mrk 421 with the ARGO-YBJ experiment
2011
ARGO-YBJ is an air shower detector array with a fully covered layer of resistive plate chambers. It is operated with a high duty cycle and a large field of view. It continuously monitors the northern sky at energies above 0.3 TeV. In this paper, we report a long-term monitoring of Mrk 421 over the period from 2007 November to 2010 February. This source was observed by the satellite-borne experiments Rossi X-ray Timing Explorer and Swift in the X-ray band. Mrk 421 was especially active in the first half of 2008. Many flares are observed in both X-ray and gamma-ray bands simultaneously. The gamma-ray flux observed by ARGO-YBJ has a clear correlation with the X-ray flux. No lag between the X-r…
Understanding the price drivers of successful apps in the mobile app market
2016
In this paper, we take the perspective of app developers. Specifically, based on a sample of top paid apps from three major app stores, i.e., App Store, Google Play, and Blackberry World, we construct a hedonic price model to examine the role of relevant factors in price formation in the app market. Our results suggest a strong evidence of two-sided market effects. In fact, the lower price charged for apps operating as two-sided markets reflect the strategy of subsidising users, due to the positive cross-side externalities they exert on valuable third parties. Surprisingly, the effects of trialability, in-app purchase and mechanisms to build reputation are not significant in the context of …
Emotion Eliciting Events in the Workplace: An Intercultural Comparison
2007
Different emotional experiences at the work place are evaluated in respect to their influence on job satisfaction. A sample of 75 Japanese employees and 169 German employees rated their emotional level following daily hassles in the work place that were attributed on the two dimensions: locus of causality and controllability. It was predicted that the same attribution pattern of daily hassles leads to different emotional responses and different levels of job satisfaction between employees with an interdependent and independent cultural background. Results indicate that equal attribution patterns of job related daily hassles lead to different emotional experiences between the two cultural gr…
Rethinking exchange and prices
2017
Our monetary economies of production are not based upon relative exchanges described by the standard theory. Money is neither a commodity nor a positive asset; it cannot be exchanged against physical goods and services. It follows that payments do not consist of mutual transfers of commodities. In fact, each producer working for the needs for the community produces wealth for himself. Further, transactions on any markets are absolute exchanges. One of the consequences of this is that market prices do not measure wealth; rather, they are coefficients of redistribution of products.
Neighborhood Characteristics, Alcohol Outlet Density, and Alcohol-Related Calls-for-Service: A Spatiotemporal Analysis in a Wet Drinking Country
2017
Alcohol outlets have been associated with different social problems, such as crime, violence, intimate partner violence, and child maltreatment. The spatial analysis of neighborhood availability of alcohol outlets is key for better understanding of these influences. Most studies on the spatial distribution of alcohol outlets in the community have been conducted in U.S. cities, but few studies have assessed this spatial distribution in other countries where the drinking culture may differ. The aim of this study was to analyze the spatiotemporal distribution of alcohol outlets in the city of Valencia, Spain, and its relationship with neighborhood-level characteristics, as well as to examine t…
Spurious source generation in mapping from noisy phase-self-calibrated data
2008
Phase self-calibration (or selfcal) is an algorithm often used in the calibration of interferometric observations in astronomy. Although a powerful tool, this algorithm presents strong limitations when applied to data with a low signal-to-noise ratio. We analyze the artifacts that the phase selfcal algorithm produces when applied to extremely noisy data. We show how the phase selfcal may generate a spurious source in the sky from a distribution of completely random visibilities. This spurious source is indistinguishable from a real one. We numerically and analytically compute the relationship between the maximum spurious flux density generated by selfcal from noise and the particulars of th…