Estrutura de financiamento das empresas start-up

Atualmente, o contexto de atuação das empresas tem sido cada vez mais desafiante dado o binómio de competitividade e crise financeira. Desta forma, a exploração de novas soluções e identificação de lacunas ou desequilíbrios no mercado torna-se imperial para o desenvolvimento das novas entidades. É com base nesta premissa que emerge o conceito de Start-Up, sendo o seu propósito o desenvolvimento de novos produtos e modelos de negócios inovadores. Como resultado, estas empresas tornam-se num elemento revitalizador do tecido económico dos países em que estão inseridas. De forma a possibilitar a potenciação das atividades desenvolvidas por estas entidades é crucial a identificação das diversas fontes de recursos financeiros e as consequentes contrapartidas exigidas. No entanto, dado o seu caráter inovador obviamente que vários são os riscos lhes estão associados, pelo que estas empresas deparam-se com mais dificuldades no momento de acesso aos recursos financeiros que pretendem. Desta forma, a presente dissertação analisa as tendências de financiamento das Start-Up tendo como motivação o facto desta temática ainda não se encontrar devidamente explorada e dado o desconhecimento desta realidade em Portugal. Neste sentido, e aliando a problemática existente com a motivação para a concretização da presente dissertação foram realizados um conjunto de inquéritos os quais foram aliados com o desenvolvimento de modelos empíricos multivariados aplicados aos dados seccionais e em painel. Os resultados alcançados com a investigação empírica permitiram concluir a influência de um conjunto de variáveis bem como justificar a orientação e estrutura de financiamento das Start-Up portuguesas. Das variáveis investigadas de ressalvar a influência significativa da Dimensão da Empresa, Estrutura de Ativos e Forma Legal no financiamento das Start-Up nacionais.

Modeling and forecasting value-at-risk for the Portuguese stock market

The aim of this work project is to find a model that is able to accurately forecast the daily Value-at-Risk for PSI-20 Index, independently of the market conditions, in order to expand empirical literature for the Portuguese stock market. Hence, two subsamples, representing more and less volatile periods, were modeled through unconditional and conditional volatility models (because it is what drives returns). All models were evaluated through Kupiec’s and Christoffersen’s tests, by comparing forecasts with actual results. Using an out-of-sample of 204 observations, it was found that a GARCH(1,1) is an accurate model for our purposes.

Impacto da crise no volume e perfil de internamento de doentes com VIH-SIDA em Portugal Continental : análise temporal 2001-2012

RESUMO - Contexto: O início da crise económica em Portugal no ano de 2009 colocou o país numa grave recessão económica aliada a diversas medidas de austeridade. Como consequência assistiu-se, ao nível nacional, uma diminuição do PIB, aumento do desemprego e assim como uma série de restrições orçamentais em várias áreas, nomeadamente a da saúde. Apesar de existir inúmeros estudos que avaliaram o impacto das recessões económicas na saúde os resultados são controversos e não existe um consenso quanto a esta associação. No que se refere às doenças infeciosas o número de estudos é bastante mais reduzido. O objetivo deste estudo foi o de analisar o impacto da crise atual no volume e perfil de internamento de doentes com VIH/SIDA, de forma a complementar a escassa evidência existente neste domínio. Metodologia: Foram analisados 53,296 episódios de internamento nos hospitais do SNS entre o ano de 2001 e 2012, cujo diagnóstico principal é a infeção pelo VIH/SIDA. Considerou-se o ano de 2009 como o ano inicial da crise. Através de regressões multivariadas avaliou-se o impacto da crise no volume de doentes internados, duração de internamento, número de co-morbilidades, risco de ser admitido via urgência e risco de mortalidade no internamento. Adicionalmente repetiu-se a análise por região NUTS II de Portugal Continental (Norte, Alentejo, LVT, Centro e Algarve). Resultados: A crise não teve impacto no volume de doentes internados. No entanto, após o ano de 2009, registou-se uma diminuição de 5.6% na duração de internamento; um aumento de 1.6% no número de co-morbilidades; um aumento de 11.1% no risco de ser admitido via urgência e um aumento de 8.6% do risco de mortalidade no internamento. As análises por região permitiram verificar que as regiões mais afetadas pela crise foram a região LVT e a região Norte. Conclusão: A crise em Portugal não teve impacto na incidência de internamentos por VIH/SIDA. Porém o aumento do número de co-morbilidades, do risco de ser admitido via urgência e do risco de mortalidade no internamento parece refletir um agravamento da severidade dos casos após o ano de 2009. Adicionalmente a diminuição da duração de internamento com o efeito da crise poderá refletir tanto aumento da eficiência dos cuidados prestados ou ao contrário, uma diminuição da sua qualidade.

A Theoretical Comparison Between Integrated and Realized Volatilies

In this paper, we provide both qualitative and quantitative measures of the cost of measuring the integrated volatility by the realized volatility when the frequency of observation is fixed. We start by characterizing for a general diffusion the difference between the realized and the integrated volatilities for a given frequency of observations. Then, we compute the mean and variance of this noise and the correlation between the noise and the integrated volatility in the Eigenfunction Stochastic Volatility model of Meddahi (2001a). This model has, as special examples, log-normal, affine, and GARCH diffusion models. Using some previous empirical works, we show that the standard deviation of the noise is not negligible with respect to the mean and the standard deviation of the integrated volatility, even if one considers returns at five minutes. We also propose a simple approach to capture the information about the integrated volatility contained in the returns through the leverage effect.

Testing Normality : A GMM Approach

In this paper, we consider testing marginal normal distributional assumptions. More precisely, we propose tests based on moment conditions implied by normality. These moment conditions are known as the Stein (1972) equations. They coincide with the first class of moment conditions derived by Hansen and Scheinkman (1995) when the random variable of interest is a scalar diffusion. Among other examples, Stein equation implies that the mean of Hermite polynomials is zero. The GMM approach we adopted is well suited for two reasons. It allows us to study in detail the parameter uncertainty problem, i.e., when the tests depend on unknown parameters that have to be estimated. In particular, we characterize the moment conditions that are robust against parameter uncertainty and show that Hermite polynomials are special examples. This is the main contribution of the paper. The second reason for using GMM is that our tests are also valid for time series. In this case, we adopt a Heteroskedastic-Autocorrelation-Consistent approach to estimate the weighting matrix when the dependence of the data is unspecified. We also make a theoretical comparison of our tests with Jarque and Bera (1980) and OPG regression tests of Davidson and MacKinnon (1993). Finite sample properties of our tests are derived through a comprehensive Monte Carlo study. Finally, three applications to GARCH and realized volatility models are presented.

Mixing compositions and other scales

Theory of compositional data analysis is often focused on the composition only. However in practical applications we often treat a composition together with covariables with some other scale. This contribution systematically gathers and develop statistical tools for this situation. For instance, for the graphical display of the dependence of a composition with a categorical variable, a colored set of ternary diagrams might be a good idea for a first look at the data, but it will fast hide important aspects if the composition has many parts, or it takes extreme values. On the other hand colored scatterplots of ilr components could not be very instructive for the analyst, if the conventional, black-box ilr is used. Thinking on terms of the Euclidean structure of the simplex, we suggest to set up appropriate projections, which on one side show the compositional geometry and on the other side are still comprehensible by a non-expert analyst, readable for all locations and scales of the data. This is e.g. done by defining special balance displays with carefully- selected axes. Following this idea, we need to systematically ask how to display, explore, describe, and test the relation to complementary or explanatory data of categorical, real, ratio or again compositional scales. This contribution shows that it is sufficient to use some basic concepts and very few advanced tools from multivariate statistics (principal covariances, multivariate linear models, trellis or parallel plots, etc.) to build appropriate procedures for all these combinations of scales. This has some fundamental implications in their software implementation, and how might they be taught to analysts not already experts in multivariate analysis

Análisis predictivo de los eventos adversos relacionados con los indicadores de eficiencia hospitalaria de una IPS de Bogotá

En este estudio se realizó un análisis predictivo de la aparición de eventos adversos de los pacientes de una IPS de Bogotá, Mederi Hospital Universitario de Barrios Unidos (HUBU) durante el año 2013; relacionados con los indicadores de eficiencia hospitalaria (Porcentaje de ocupación hospitalaria, número de egresos hospitalarios, promedio de estancia hospitalaria, número de egresos de urgencias, promedio de estancia en urgencias). Los datos fueron exportados a una matriz de análisis de las variables cualitativas; fueron presentadas con frecuencias absolutas y relativas, las variables cuantitativas (edad, tiempos de estancia) fueron presentadas con media, desviaciones estándar. Se agruparon los datos de eventos adversos y de eficiencia hospitalaria en una nueva matriz que permitiera el análisis predictivo la nueva matriz fue exportada al software de modelación estadístico Eviews 6.5; se especificaron modelos predictivos multivariados para la variable número de eventos adversos, respecto de los indicadores de eficiencia hospitalaria y se estimaron las probabilidades de ocurrencia, análisis de correlación y multicolinealidad; los resultados se presentaron en tablas de estimación para cada modelo, se restringieron los eventos adversos prevenibles y no prevenibles información obtenida a través de un sistema de información que registra los factores relacionados con la ocurrencia de eventos adversos en salud, a través del sistema de reporte de eventos en salud, reporte en las historias clínicas, reporte individual, reporte por servicio, análisis de datos y estudios de caso, de la misma forma fueron extraídos los datos de eficiencia hospitalaria para el mismo periodo. El análisis y gestión de eventos adversos pretende establecer estrategias de mejoramiento continuo y análisis de resultados frente a los indicadores de eficiencia que permitan intervención de los factores de riesgo operativo de los servicios del Hospital Universitario de Barrios Unidos (HUBU), relacionados con eventos adversos en la atención de los pacientes en especial se debe enfocar en la gestión de los egresos de pacientes de acuerdo a los resultados obtenidos con el fin de alinearse y fortalecer las políticas de seguridad del paciente para brindar una atención integral con calidad y eficiencia, disminuyendo las quejas en la atención, las glosas, los riesgos jurídicos, de acuerdo al modelo predictivo estudiado.

Preferred structures in large-scale circulation and the effect of doubling greenhouse gas concentration in HadCM3

Preferred structures in the surface pressure variability are investigated in and compared between two 100-year simulations of the Hadley Centre climate model HadCM3. In the first (control) simulation, the model is forced with pre-industrial carbon dioxide concentration (1×CO2) and in the second simulation the model is forced with doubled CO2 concentration (2×CO2). Daily winter (December-January-February) surface pressures over the Northern Hemisphere are analysed. The identification of preferred patterns is addressed using multivariate mixture models. For the control simulation, two significant flow regimes are obtained at 5% and 2.5% significance levels within the state space spanned by the leading two principal components. They show a high pressure centre over the North Pacific/Aleutian Islands associated with a low pressure centre over the North Atlantic, and its reverse. For the 2×CO2 simulation, no such behaviour is obtained. At higher-dimensional state space, flow patterns are obtained from both simulations. They are found to be significant at the 1% level for the control simulation and at the 2.5% level for the 2×CO2 simulation. Hence under CO2 doubling, regime behaviour in the large-scale wave dynamics weakens. Doubling greenhouse gas concentration affects both the frequency of occurrence of regimes and also the pattern structures. The less frequent regime becomes amplified and the more frequent regime weakens. The largest change is observed over the Pacific where a significant deepening of the Aleutian low is obtained under CO2 doubling.

The long-run performance of IPOs: the case of the Stock Exchange of Mauritius

This study examines the long-run performance of initial public offerings on the Stock Exchange of Mauritius (SEM). The results show that the 3-year equally weighted cumulative adjusted returns average −16.5%. The magnitude of this underperformance is consistent with most reported studies in different developed and emerging markets. Based on multivariate regression models, firms with small issues and higher ex ante financial strength seem on average to experience greater long-run underperformance, supporting the divergence of opinion and overreaction hypotheses. On the other hand, Mauritian firms do not on average time their offerings to lower cost of capital and as such, there seems to be limited support for the windows of opportunity hypothesis.

Time varying price discovery

We show how multivariate GARCH models can be used to generate a time-varying “information share” (Hasbrouck, 1995) to represent the changing patterns of price discovery in closely related securities. We find that time-varying information shares can improve credit spread predictions.

Fatigue and workability in Brazilian textile companies in different corporate social responsibility score groups

The aim of this study was to evaluate working conditions in the textile industry for different stages of Corporate Social Responsibility (CSR) development, and workers` perception of fatigue and workability. A cross-sectional study was undertaken with 126 workers in the production areas of five Brazilian textile plants. The corporate executive officers and managers of each company provided their personal evaluations of CSR. Companies were divided into 2 groups (higher and lower) of CSR scores. Workers completed questionnaires on fatigue, workability and working conditions. Ergonomic job analysis showed similar results for working conditions, independent of their CSR score. Multivariate analysis models were developed for fatigue and workability, indicating that they are both associated to factors related to working conditions and individual workers` characteristics and life styles. Work organization, (what, how, when, where and for how long the work is done), is also an associated factor for fatigue. This study suggests that workers` opinions should be taken into greater consideration when companies develop their CSR programs, in particular for those relating to working conditions. Relevance to industry: This paper underlines the importance of considering working conditions and workers` opinions of them, work organization and individual workers` characteristics and life styles in order to restore or to maintain workability and to reduce fatigue, independently of how developed a company may be in the field of Corporate Social Responsibility. (C) 2010 Elsevier B.V. All rights reserved.

Variable definitions: implications for the prediction of pulmonary complications after adult cardiac surgery

Aim: The aim of this paper was to review the implications that variable definitions have for the prediction of post-operative pulmonary complications after cardiac surgery.

Method: A review of the literature from 1980 to 2002. Selected studies demonstrated an original attempt to examine multivariate associations between pre, intra or post-operative antecedents and pulmonary outcomes in patients undergoing coronary artery bypass grafting (CABG). Reports that described the validation of established clinical prediction rules, testing interventions or research conducted in non-human cohorts were excluded from this review.

Results: Consistently, variable factor and outcome definitions are combined for the development of multivariate prediction models that subsequently have limited clinical value. Despite being prevalent there are very few attempts to examine post-operative pulmonary complications (PPC) as endpoints in isolation. The trajectory of pulmonary dysfunction that precedes complications in the post-operative context is not clear. As such there is little knowledge of post-operative antecedents to PPC that are invariably excluded from model development.

Conclusion: Multivariate clinical prediction rules that incorporate antecedent patient and process factors from the continuum of cardiovascular care for specific pulmonary outcomes are recommended. Models such as these would be useful for practice, policy and quality improvement.

Market makers v's the general public : a first look at S & P500 futures trade data

This paper considers 15 minute records of trading volume and traded prices coinciding with the reporting intervals required by the Commodity Futures Trading Commission. Records are extracted from trade records for market trade and also two way trade between market makers (CT1) and the general public (CT4) from January 1994 to June 2004. Futures price records are matched with S&P500 cash index price records. Simultaneous volatility models are specified and estimated to test trading volume to futures volatility lead/lag effects and also futures volatility to cash index volatility lead/lag effects. As we disaggregate from the market records to CT1 and CT4 records and further into year to year samples volume to futures volatility leading effects and also futures volatility to cash volatility leading effects dominate. The results raise important issues for risk management and dynamic hedging models employing intra-day trader data. A number of important issues for further analysis are also raised in this paper.

Dispersion of information or market behaviour : general public trading in S & P 500 index futures

This paper considers 15 minute records of trading volume and traded prices coinciding with the reporting intervals required by the Commodity Futures Trading Commission. Records are extracted from trade records for two way trade between market makers (CTI1) and the general public (CTI4) from January 1994 to June 2004. Futures price records are matched with S&P500 cash index price records. Simultaneous volatility models are specified and estimated to test trading volume to futures volatility lead/lag effects and also futures volatility to cash index volatility lead/lag effects. There is evidence that existing theoretical models of the general public trading behaviour do not explain such behaviour in these very actively traded markets. These effects can depend more on market conditions than what is suggested in theoretical models.

Socio-demographic correlates of prolonged television viewing time in Australian men and women : the AusDiab study

Background: Sedentary behaviors, particularly television viewing (TV) time, are associated with adverse health outcomes in adults, independent of physical activity levels. These associations are stronger and more consistent for women than for men. Methods: Multivariate regression models examined the sociodemographic correlates of 2 categories of TV time (≥2 hours/day and ≥4 hours/day); in a large, population-based sample of Australian adults (4950 men, 6001 women; mean age 48.1 years, range 25-91) who participated in the 1999/2000 Australian Diabetes, Obesity, and Lifestyle (AusDiab) study. Results: Some 46% of men and 40% of women watched ≥ 2 hours TV/day; 9% and 6% respectively watched ≥ 4 hours/day. For both men and women, ≥2 hours TV/day was associated with less than tertiary education, living outside of state capital cities, and having no paid employment. For women, mid and older age (45-64 and 65+) were also significant correlates of ≥2 hours TV/day. Similar patterns of association were observed in those viewing ≥4 hours/day. Conclusions: Prolonged TV time is associated with indices of social disadvantage and older age. These findings can inform the understanding of potential contextual influences and guide preventive initiatives.