Search results for "Case studie"
showing 10 items of 65 documents
Dades massives i estadística: La perspectiva d'un estadístic
2014
Les dades massives (big data) representen un recurs sense precedents per a afrontar reptes científics, econòmics i socials, però també incrementen la possibilitat de traure conclusions enganyoses. Per exemple, l’ús d’enfocaments basats exclusivament en dades i que es despreocupen de comprendre el fenomen en estudi, que s’orienten a un objectiu esmunyedís i canviant, que no tenen en compte problemes determinants en la recopilació de dades, que resumeixen o «cuinen» inadequadament les dades i que confonen el soroll amb el senyal. Repassarem alguns casos reeixits i il·lustrarem com poden ajudar els principis de l’estadística a obtenir una informació més fiable de les dades. També abordarem els…
Survival of immediately versus delayed loaded short implants: a prospective case series study
2015
Background: To assess and compare survival rates of immediately and delayed loaded short implants (7 mm) in free ends of a partially edentulous jaw with moderate-severe alveolar bone resorption. Material and Methods: 24 patients with atrophic edentulous free-ends were included in this prospective study. Four study groups were monitored monthly and their behavior was evaluated: bridges supported only by short implants and mixed short and long implant bridge groups, both with immediate and delayed loading. Failures, bone loss, probing depth and bleeding on probing were evaluated. Results: 54 Mk III Shorty TiU and 15 Brånemark System®MK III TiU implants with a length longer than 7mm were inclu…
In vitro study of the apical microleakage with resilon root canal filling using different final endodontic irrigants
2015
Background: Endodontic microleakage or microfiltration refers to the percolation of fluids and micro-organisms at the interface of the obturation material and the walls of the root canal system. The aim of this in vitro study was to compare apical microfiltration of Resilon root canal filling by employing three dif ferent final irrigant solutions. Material and Methods: 128 single-rooted teeth were employed. The crowns were sectioned horizontally at the cemento-enamel junction and instrumented with 5.25% sodium hypochlorite (NaOCl) and 17% EDTA gel to obtain an instrumented 040 apical caliber. An intermediate irrigation was performed with distilled water. The roots were then randomly assigne…
Cavidad de Stafne: Estudio retrospectivo de 11 casos
2006
Podeu consultar la versió en anglès a: http://hdl.handle.net/2445/48487
Twenty-year trends in the prevalence of Down syndrome and other trisomies in Europe : impact of maternal age and prenatal screening
2013
This study examines trends and geographical differences in total and live birth prevalence of trisomies 21, 18 and 13 with regard to increasing maternal age and prenatal diagnosis in Europe. Twenty-one population-based EUROCAT registries covering 6.1 million births between 1990 and 2009 participated. Trisomy cases included live births, fetal deaths from 20 weeks gestational age and terminations of pregnancy for fetal anomaly. We present correction to 20 weeks gestational age (ie, correcting early terminations for the probability of fetal survival to 20 weeks) to allow for artefactual screening-related differences in total prevalence. Poisson regression was used. The proportion of births in …
Pair interactions in online assessments of collaborative problem solving: case-based portraits
2018
This exploratory case study focuses on how pairs of students can build a shared understanding and acquire collaborative problem-solving (CPS) practices during an online assessment of CPS skills, which is seen in the context of the CPS construct, in a symmetrical and asymmetrical task type. Even though CPS is widely recognised as a core twenty-first-century competency, its nature is not yet well understood. Also, until recently, most of studies have focused on the individual’s solution to a problem or on the skills individuals bring into a problem-solving space. This study extends from an individual- to group-level focus in CPS, emphasising the role and quality of the social aspects in CPS p…
Experimenting lean dynamic performance management systems design in SMEs
2018
Purpose The purpose of this paper is to frame the potential benefits of lean dynamic performance management (PM) systems for small and micro-enterprises. Such systems may exploit the entrepreneur’s tacit knowledge and build on managerial competencies, by incorporating individual attributes into organisational routines. Design/methodology/approach The paper suggests the use of insight models based on the combination of lean PM tools and system dynamics (SD) modelling. Based on a number of exemplary cases, the paper discusses the potential benefits of these models, in respect to four specific contexts: artisan, new company start-up, established firm and micro-giant company. Related to such c…
Dynamic reconfiguration systems for PV plant: Technical and economic analysis
2020
Solar plants suffer of partial shading and mismatch problems. Without considering the generation of hot spots and the resulting security issues, a monitoring system for the health of a PV plant should be useful to drive a dynamic reconfiguration system (DRS) to solve bottlenecks due to different panels’ shading. Over the years different DRS architectures have been proposed, but no suggestions about costs and benefits have been provided. Starting from technical subjects such as differences of the topologies driving the hardware complexity and number of components, this paper identifies the cost of DRS and its lifetime, and based on these issues it provides an economic analysis for a 6 kWp PV…
Reverse electrodialysis heat-engine: Case studies of improving energy efficiency through recovery of low temperature excess heat
2018
Reverse Electrodialysis (RED) is a technology for generating electricity from the difference in salinity between two solutions. RED is usually applied to natural water streams with different salinities, like seawater vs. freshwater. In the RED Heat-to-Power project we explore the option of using artificial water solutions operating in a closed loop where the difference in salinity is regenerated in a separation step powered by heat at temperature ranges between 60 and 100°C. We call this system Reverse Electrodialysis Heat Engine (RED HE). In this paper, first we summarise the possible system configurations and the overall amount of excess heat available in Europe for powering the RED HE pr…
DSCG 3 : management et contrôle de gestion
2015
Cet ouvrage propose plusieurs études de cas conçues au modèle des sujets de l'examen. Chacun des cas est suivi de son corrigé détaillé. Les thèmes traités dans les différentes études se complètent de sorte que l'ouvrage couvre l'ensemble du programme