8 resultados para Bias-corrected average forecast


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Background: Little is known about the risk of progression to hazardous alcohol use in people currently drinking at safe limits. We aimed to develop a prediction model (predictAL) for the development of hazardous drinking in safe drinkers. Methods: A prospective cohort study of adult general practice attendees in six European countries and Chile followed up over 6 months. We recruited 10,045 attendees between April 2003 to February 2005. 6193 European and 2462 Chilean attendees recorded AUDIT scores below 8 in men and 5 in women at recruitment and were used in modelling risk. 38 risk factors were measured to construct a risk model for the development of hazardous drinking using stepwise logistic regression. The model was corrected for over fitting and tested in an external population. The main outcome was hazardous drinking defined by an AUDIT score >= 8 in men and >= 5 in women. Results: 69.0% of attendees were recruited, of whom 89.5% participated again after six months. The risk factors in the final predictAL model were sex, age, country, baseline AUDIT score, panic syndrome and lifetime alcohol problem. The predictAL model's average c-index across all six European countries was 0.839 (95% CI 0.805, 0.873). The Hedge's g effect size for the difference in log odds of predicted probability between safe drinkers in Europe who subsequently developed hazardous alcohol use and those who did not was 1.38 (95% CI 1.25, 1.51). External validation of the algorithm in Chilean safe drinkers resulted in a c-index of 0.781 (95% CI 0.717, 0.846) and Hedge's g of 0.68 (95% CI 0.57, 0.78). Conclusions: The predictAL risk model for development of hazardous consumption in safe drinkers compares favourably with risk algorithms for disorders in other medical settings and can be a useful first step in prevention of alcohol misuse.

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A Work Project, presented as part of the requirements for the Award of a Masters Degree in Economics from the NOVA – School of Business and Economics

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A PhD Dissertation, presented as part of the requirements for the Degree of Doctor of Philosophy from the NOVA - School of Business and Economics

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The oldest Portuguese share index still being calculated is the BVL/PSI-General, one which started the daily series on 5/Jan/1988 with a base value of 1000 points. Everyday a single value is computed based on the closing prices of all the shares included in the sample. Also, all corporate events affecting the price of any share beyond market sentiment are taken into account through proper adjustments, either in the numerator or the denominator of the formula. However, for dates before January 1988, there is nothing comparable to this index since the two different series known either never disclosed the methodology adopted to calculate the index or followed solutions not compatible with the above index. The present paper explains the solutions adopted to replicate as closely as possible the methodology of the BVL-General index to the main market of the Lisbon Exchange for the period 1978 – 1987. This is the first estimate of the historical Equity Risk Premium in Portugal above short-term risk-free rate from the re-opening of the market following the Carnation Revolution (and the accompanying nationalizations), to the present. In showing a value of the same order of magnitude found in other countries, the paper invites further studies on the effects of political decisions such as privatizations and joining the European Union.

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This work presents the archaeometallurgical study of a group of metallic artefacts found in Moinhos de Golas site, Vila Real (North of Portugal), that can generically be attributed to Proto-history (1st millennium BC, Late Bronze Age and Iron Age). The collection is composed by 35 objects: weapons, ornaments and tools, and others of difficult classification, as rings, bars and one small thin bent sheet. Some of the objects can typologically be attributed to Late Bronze Age, others are of more difficult specific attribution. The archaeometallurgical study involved x-ray digital radiography, elemental analysis by micro-energy dispersive X-ray fluorescence spectrometry and scanning electron microscopy with energy dispersive spectroscopy, microstructural observations by optical microscopy and scanning electron microscopy. The radiographic images revealed structural heterogeneities frequently related with the degradation of some artefacts and the elemental analysis showed that the majority of the artefacts was produced in a binary bronze alloy (Cu-Sn) (73%), being others produced in copper (15%) and three artefacts in brass (Cu-Zn(-Sn-Pb)). Among each type of alloy there’s certain variability in the composition and in the type of inclusions. The microstructural observations revealed that the majority of the artefacts suffered cycles of thermo-mechanical processing after casting. The diversity of metals/alloys identified was a discovery of great interest, specifically due to the presence of brasses. Their presence can be interpreted as importations related to the circulation of exogenous products during the Proto-history and/or to the deposition of materials during different moments at the site, from the transition of Late Bronze Age/Early Iron Age (Orientalizing period) onwards, as during the Roman period.

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This marketing plan project is a culmination of extensive strategies with the use of experiential marketing to address issues confronting the Kenyan tourism industry in order to have a sustainable tourism sector. Following the terrorist attack carried out by Islamist militants’ belonging to al-Shabaab terrorist organization on Nairobi’s Westgate shopping mall in September 2013, tourist forecast has gone down sharply with an average of 20% fall in tourists’ arrivals which is likely to have an impact on the tourism sector in Kenya. Even before the deadly attack on Westgate, the most lethal attack by Islamist terrorists in 15 years in Kenya, the government through the Kenya tourist board had announced that in 2013 tourist arrivals were down by 12%, at 495,978, according to an October 2013 report by Bloomberg. Tourism revenues were also down by 7.4%, over FY12/13 (July-June) to reach KES96.24bn, according to a September 2013 report on the local Capital FM website. Beyond 2013, much will depend on how quickly the Kenya tourist board can regain control of the situation. The Kenyan government believes that the Westgate mall attack was a 'one-off' incident, with a low probability of a similar event happening again over the short term period. Germany, United States, United Kingdom, Australia, Italy, France and Canada continue to be the key source market however; the Kenya tourist board can make continued growth stronger from new emerging markets in order to increase new arrivals into the country. The marketing plan outlines the objectives to be implemented and provides the implementation strategy, activity plans, monitoring and evaluation plans, financial requirements projections and proposes a new structure of experiential marketing. A number of regional forces are identified that will impact tourism into the country including global, social and economic forces, emerging trends in visitor motivations and behavior, emerging forces in experiential marketing. A major component of the strategy identifies target markets for Kenya to commensurate with the level of resources that will be available for marketing and promotion, in keeping with the forces and trends identified and the nature of the Kenya tourism environment. The agreed upon target market segments are: generic/mass travel, experiential travel, creative travel, adventure seeking travel, senior/extended/long stay travel, and business related travel. The strategy phases the development of the target markets over the years of the marketing strategies in order to yield the best opportunity for results. A core activity in developing a marketing strategy is determining the nature of experiences Kenya offers in tourism. The strategy’s experience development process will continue to develop within the context of the products identified which will be promoted regionally: culture/heritage, nature, community-based. Each county in the country has a significant number of attractions and experiences and the challenge of the country is to bring these together in a creative and innovative way in order to encourage tourists to visit more than one county in Kenya.

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RESUMO - Introdução: A integração vertical de cuidados surge em Portugal em 1999 com a criação da primeira Unidade Local de Saúde (ULS) em Matosinhos. Este modelo de gestão tem como principal objetivo reorganizar o sistema para responder de forma mais custo-efetiva às necessidades atuais. Objetivo: Analisar o impacto da criação das ULS nos custos do internamento hospitalar português. Metodologia: Para apurar o custo médio estimado por episódio de internamento hospitalar utilizou-se a metodologia dos Custos Estimados com base na Contabilidade Analítica. Contudo, não foram imputados custos por diária de internamento por centro de produção, mas apenas por doente saído em determinado hospital. Para efeitos de comparação dos modelos de gestão organizacionais consideraram-se variáveis demográficas e variáveis de produção. Resultados: Da análise global, os hospitais integrados em ULS apresentam um custo médio estimado por episódio de internamento inferior quando comparados com os restantes. Em 2004 os hospitais sem modelo de integração vertical de cuidados apresentam uma diferença de custos de aproximadamente 714,00€. No ano 2009, último ano em análise, esta diferença é mais ténue situando-se nos 232,00€ quando comparados com hospitais integrados em ULS. Discussão e Conclusão: Não existe uma tendência definida no que respeita à diferença de custos quando se comparam os diferentes modelos organizacionais. É importante que em estudos futuros se alargue a amostra ao total de prestadores e se aprofundem os fatores que influênciam os custos de internamento. A compreensão dos indicadores sociodemográficos, demora média, e produção realizada, numa ótica de custo efetividade e qualidade, permitirá resultados com menor grau de viés.

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It is well known that, unless worker-firm match quality is controlled for, returns to firm tenure (RTT) estimated directly via reduced form wage (Mincer) equations will be biased. In this paper we show that even if match quality is properly controlled for there is a further pervasive source of bias, namely the co-movement of firm employment and firm wages. In a simple mechanical model where human capital is absent and separation is exogenous we show that positively covarying shocks (either aggregate or firm level) to firms employment and wages cause downward bias in OLS regression estimates of RTT. We show that the long established procedures for dealing with "traditional" RTT bias do not circumvent the additional problem we have identified. We argue that if a reduced form estimation of RTT is undertaken, firm-year fixed effects must be added in order to eliminate this bias. Estimates from two large panel datasets from Portugal and Germany show that the bias is empirically important. Adding firm-year fixed effects to the regression increases estimates of RTT in the two respective countries by between 3.5% and 4.5% of wages at 20 years of tenure over 80% (50%) of the estimated RTT level itself. The results extend to tenure correlates used in macroeconomics such as the minimum unemployment rate since joining the firm. Adding firm-year fixed effects changes estimates of these effects also.