Search results for "crossing"
showing 7 items of 167 documents
La stima del crossing-point nel modello di Cox per l'analisi di sopravvivenza: una proposta
2008
La variazione dell'effetto di un fattore di rischio in un modello di sopravvivenza a rischi proporzionali di Cox è di particolare interesse in molte applicazioni, in quanto l'allontanamento dall'ipotesi di proporzionalità dei rischi rende il modello inadeguato. Di particolare interesse è il caso in cui le funzioni di rischio di due gruppi si intersecano, ovvero, più in generale, il coefficiente di regressione cambia segno dopo un istante temporale detto crossing-point. In questo lavoro si propone una procedura per la stima del crossing-point applicabile anche al caso di variabili quantitative, e si discutono tre diversi metodi per la corrispondente stima intervallare. L'approccio è illustra…
Examining Open Innovation in Science (OIS): what Open Innovation can and cannot offer the science of science
2021
Scholars across disciplines increasingly hear calls for more open andcollaborative approaches to scientific research. The concept of OpenInnovation in Science (OIS) provides a framework that integratesdispersed research efforts aiming to understand the antecedents,contingencies, and consequences of applying open and collaborativeresearch practices. While the OIS framework has already been taken upby science of science scholars, its conceptual underpinnings requirefurther specification. In this essay, we critically examine the OIS conceptand bring to light two key aspects: 1) how OIS builds upon OpenInnovation (OI) research by adopting its attention to boundary-crossingknowledge flows and by…
Constructing a pedagogical practice across disciplines in pre-service teacher education
2019
In this paper we report a qualitative case study of a teaching intervention in which a pre-service subject teacher pair planned and conducted a course integrating Finnish language and ethics in a multilingual setting. Audio-recorded planning sessions and interviews including learning diaries were analysed using qualitative content analysis to identify the dynamics of collaborative cross-curricular pedagogical practice development and pedagogical language knowledge. The analysis revealed tensions in crossing the boundary between language and content knowledge. The study suggests that when creating cross-curricular practices, student teachers benefit from longer-term processes and theory-base…
Pathways and pedestrian crossings: indicators of quality and safety
2014
Pedestrian mobility can be considered an important feature in a new model of town organization. Enhancing pedestrian mobility could bring new life and activities in the old and historic parts of the town reviving their original identities. The planning of new quarters is often performed considering a wide use of private cars, this resulting in urban highways and long and winding local roads hindering pedestrian mobility and safe-ty. Town social features and mobility purpose, related to pedestrian age, are important elements to define the Pedestrian Safety Indicators. Using a GIS software, an evaluation of risk was carried out along a main urban road in order to study and develop measures to…
Non-crossing quantile regression via monotone B-spline varying coefficients
2019
Quantile regression can be used to obtain a nonparametric estimate of a conditional quantile function. The presence of quantile crossing, however, leads to an invalid distribution of the response and makes it dicult to use the tted model for prediction. In this work, we show that crossing can be alleviated or completely eliminated by explicit modeling of the regression coecients as a function of the percentile values in (0,1). We illustrate the approach via a wellknown dataset by emphasizing dierences with respect to the competitors.
Molecule-like photodynamics of Au102(pMBA)44 nanocluster.
2015
Photophysical properties of a water-soluble cluster Au102(pMBA)44 (pMBA = para-mercaptobenzoic acid) are studied by ultrafast time-resolved mid-IR spectroscopy and density functional theory calculations in order to distinguish between molecular and metallic behavior. In the mid-IR transient absorption studies, visible or near-infrared light is used to electronically excite the sample, and the subsequent relaxation is monitored by studying the transient absorption of a vibrational mode in the ligands. Based on these studies, a complete picture of energy relaxation dynamics is obtained: (1) 0.5-1.5 ps electronic relaxation, (2) 6.8 ps vibrational cooling, (3) intersystem crossing from the low…
Role of Vibrational Dynamics in Electronic Relaxation of Cr(acac)3
2015
Ultrafast energy relaxation of Cr(acac)3 dissolved in tetrachloroethylene (TCE) is studied by time-resolved infrared (TRIR) spectroscopy by using electronic and vibrational excitation. After electronic excitation at 400 or 345 nm, the ground state recovers in two time scales: 15 ps (major pathway) and 800 ps (minor pathway), corresponding to fast electronic transition to the ground state and intermediate trapping on the long-lived (2)E state followed by intersystem crossing (ISC) to the ground state. The quantum yield for the fast recovery of the ground state depends on the excitation wavelength, being higher for 345 nm. Vibrational cooling (VC) occurs on the electronic excited states with …