3,003 research outputs found
Skewness in Financial Returns: Evidence from the Portuguese Stock Market (in English)
This paper addresses the issue of symmetry in financial returns. The return distributions of the major stocks traded on the Portuguese market and included in the PSI-20 Index are examined for periods from four to nine years. The results show that the symmetry of the returns is rejected against several alternative distributions. Statistically significant differences between returns below and above the mean are detected, which provides additional evidence of skewness in the return distributions. In addition, as observed in other studies, it is interesting to note that such results are similar to other low-capitalization and low-volume markets, which also exhibit asymmetric return distributions.stock markets, skewness, financial returns
Avaliação de Estratégias de Investimento com Opções
The financial literature has revealed that option strategies originate asymmetric return distributions, providing new investment opportunities, especially in the control and reduction of risk. In this way, it is important to evaluate the performance of investment strategies that result from the combination of stock and option positions. On the other hand, given the inadequacy of the measures based upon mean and variance, new evaluation methodologies have been developed and adapted to the context of such investment strategies, of which we highlight the work of Leland (1999), that proposes a modification of the traditional risk measure (beta) of CAPM to incorporate other moments of the return distributions. In this context, we applied the methodology of Leland on six dynamic hedging strategies with options on the Index FTSE 100 in the sense of evaluating its performance. The results indicate that the new risk measure is more statistical significant than the traditional beta of CAPM, for that the information supplied by the measure of the performance (modified alpha) seems to be more reliable. On the other hand, the values of modified alphas reveal that these dynamic strategies result in excess returns close to zero (as theoretically expected), denouncing that the market price of these options appears to be in equilibrium.risk management, skewness, option strategies
O impacto da inovação no desempenho económico-financeiro das empresas da indústria transformadora portuguesa
É opinião geral que a inovação desempenha um papel essencial na performance económico-financeira. Fica-se, no entanto, muitas vezes, com a sensação de que esta afirmação se refere indistintamente ao crescimento económico em geral, à competitividade das economias nacionais, à concorrência, à rendibilidade, à sobrevivência e ao crescimento de empresas individuais. Daí a necessidade de informação empírica, precisa, que ajude a clarificar como? quando? em que sentido? em que amplitude? a inovação é importante no desempenho económico-financeiro da empresa. Nesta investigação, procurou-se dar um contributo para um melhor conhecimento destas questões, estabelecendo, assim, como objectivo principal: analisar o impacto da inovação no desempenho económico-financeiro das empresas industriais portuguesas ao longo do período 1995-2001. Os resultados obtidos mostram: (i) que a inovação tem impacto positivo no desempenho económico- financeiro das empresas industriais portuguesas, num determinado momento (1997); e (ii) que existem variáveis de inovação afectas às fases do modelo de investigação (input, output e desempenho) que têm impacto no curto e médio/longo prazos no desempenho económico-financeiro da empresa, confirmando-se, assim, as hipóteses da investigação.It is widely accepted that innovation plays a major role as far as economic and financial performance is concerned. Quite often, however, one gets the impression that this statement comprises indiscriminately many different aspects such as economic growth in general, national economy competitiveness, competition, profitability as well as individual business firms’ survival and growth. Therefore, it is important to develop empirical research to help clarify how, when, in what sense and how much innovation may affect the business firms economic and financial performance. With this study, the authors wish to give a contribution to a better knowledge of these issues aiming mainly at analysing innovation’s positive impact on Portuguese industrial business firms’ economic and financial performance for the period between 1995 and 2001. The results thus obtained show that (i) innovation has a positive impact on Portuguese business firms’ economic and financial performance at a certain moment in time (1997); and (ii) there are innovation variables concerning the research model stages (input, output and performance) which have an impact on the business firm’s economic an financial short, medium and long term performance which confirms this study’s hypotheses
An overview of omnichannel interaction in health care services
The adoption of omnichannel interaction services in health care can bring significant benefits to both health care institutions and their patients. The ongoing health pandemic caused by coronavirus disease has further emphasized the need for health care providers to implement an omnichannel strategy to provide seamless personalized experiences to their patients through multiple access channels. This study aimed to examine the current state of research on omnichannel interaction services in health care with a focus on the benefits, challenges, and issues that health care institutions may encounter when adopting this strategy. A systematic literature review was conducted to synthesize the current state of research and provide a comprehensive overview of the field. The results of the review were used to perform a strengths, weaknesses, opportunities, and threats analysis of omnichannel services in health care and identify 5 key criteria that health care institutions should consider when implementing an omnichannel strategy. This study contributes to the field by offering an updated and comprehensive understanding of omnichannel interaction services in health care and provides valuable insights for health care providers considering this strategy. The ultimate goal of an omnichannel strategy in health care is to improve patient engagement, increase access to care, and reduce costs while improving communication and collaboration among health care providers. The successful implementation of this strategy requires a well-defined plan, robust technology, infrastructure, data analytics, capabilities, trained professionals, and a basic understanding of the communication channels among patients. The adoption of an omnichannel strategy in health care can lead to new business growth and increased patient engagement, but health care institutions must be properly aligned and patients must be prepared for its implementation
Data Mesh: concepts and principles of a paradigm shift in data architectures
Inherent to the growing use of the most varied forms of software (e.g., social applications), there is the creation and storage of data that, due to its characteristics (volume, variety, and velocity), make the concept of Big Data emerge. Big Data Warehouses and Data Lakes are concepts already well established and implemented by several organizations, to serve their decision-making needs. After analyzing the various problems demonstrated by those monolithic architectures, it is possible to conclude about the need for a paradigm shift that will make organizations truly data-oriented. In this new paradigm, data is seen as the main concern of the organization, and the pipelining tools and the Data Lake itself are seen as a secondary concern. Thus, the Data Mesh consists in the implementation of an architecture where data is intentionally distributed among several Mesh nodes, in such a way that there is no chaos or data silos, since there are centralized governance strategies and the guarantee that the core principles are shared throughout the Mesh nodes. This paper presents the motivation for the appearance of the Data Mesh paradigm, its features, and approaches for its implementation.- (undefined
Health beliefs and attitudes toward Influenza and COVID-19 vaccination in Portugal: a study using a mixed-method approach
Sec. Infectious Diseases: Epidemiology and PreventionIntroduction: Vaccination is one of the most effective population strategies to prevent infectious diseases and mitigate pandemics, and it is important to understand vaccine uptake determinants since vaccine hesitancy has been increasing for the past few decades. The Health Belief Model (HBM) has been widely used for understanding vaccination behavior. The current study aimed to assess influenza vaccine (IV) non-uptake and attitudes toward COVID-19 vaccination, two important respiratory diseases with similar symptoms, and routes of transmission in the Portuguese population.
Methods: We conducted a cross-sectional study using a panel sample of randomly chosen Portuguese households. A total of 1,050 individuals aged 18 years and over responded to a telephone or online questionnaire. Through a mixed-method approach, we employed thematic content analysis to describe reasons for not taking the IV, considering the HBM dimensions, and quantitative statistical analysis to estimate IV and COVID-19 vaccine coverage.
Results: The IV uptake for the overall population was 30.7% (CI 95%: 26.5, 35.2). Susceptibility was found to be a main factor for IV non-uptake, followed by barriers, such as stock availability and fear of adverse effects. The uptake of the COVID-19 vaccine was very high in the study population (83.1%, CI 95%: 13.6%−20.9%). There was a high perception of COVID-19-associated severity and fear of the consequences. Individuals who reported IV uptake seemed to perceive a higher severity of COVID-19 and a higher benefit of taking the COVID-19 vaccine for severe complications.
Discussion: Thus, the population does not seem to consider influenza to be a health risk, as opposed to COVID-19, which is considered to be a possibly severe disease. The association between IV uptake and COVID-19 perceptions highlights that an overall attitude toward vaccination in general may be an important individual determinant.info:eu-repo/semantics/publishedVersio
Effects of dual-task interventions on gait performance of patients with parkinson’s disease: a systematic review
OBJECTIVE: Parkinson’s disease is characterized by motor and non-motor symptoms that impair patients’ gait performance, especially while performing dual/concurrent tasks. These deficits impair patients’ daily function, because dual-tasking is a crucial ability in terms of everyday living. The aim of this study was to systematically review the effects of dual task interventions on gait performance of patients with Parkinson’s disease.
METHOD: Studies were retrieved from MEDLINE/PubMed, LILACS and SciELO. We used the PICOS strategy to determine eligibility criteria. The search strategy included an advanced search on the included databases, using the following search query: “Parkinson’s Disease” AND “Double Task” OR “Concurrent Tasks” OR “Gait” AND “Walk”. Study selection was carried out by two independent researchers and a third one was called when consensus was needed.
RESULTS: A total of 188 articles were identified: 169 articles from Medline/PubMed, 10 articles in SciELO, 8 articles in LILACS and 1 item from manual searches. A total of 56 articles were analyzed regarding the eligibility and exclusion criteria based on full text. A final total of 7 studies were included in the systematic review.
CONCLUSION: The different types of dual-task interventions reported (dance, sound stimuli, visual and somatosensory) were associated to improvements in several gait performance indicators of Parkinson’s disease patients, including gait speed, stride time and length, cadence and step length. External stimuli seem to play a critical role on specific training effects on dual-task gait performance.info:eu-repo/semantics/publishedVersio
Analyzing Geospatial patterns of syrian refugee flows in southeastern Turkey by use of remote sensing and complementary data
Crisis-affected communities and global organizations for international aid are becoming increasingly digital as consequence geotechnology popularity. Humanitarian sector changed in profound ways by adopting new technical approach to obtain information from area with difficult geographical or political access. Since 2011, turkey is hosting a growing number of Syrian refugees along southeastern region. Turkish policy of hosting them in camps and the difficulty created by governors to international aid group expeditions to get information, made such international organizations to investigate and adopt other approach in order to obtain information needed. They intensified its remote sensing approach. However, the majority of studies used very high-resolution satellite imagery (VHRSI). The study area is extensive and the temporal resolution of VHRSI is low, besides it is infeasible only using these sensors as unique approach for the whole area. The focus of this research, aims to investigate the potentialities of mid-resolution imagery (here only Landsat) to obtain information from region in crisis (here, southeastern Turkey) through a new web-based platform called Google Earth Engine (GEE). Hereby it is also intended to verify GEE currently reliability once the Application Programming Interface (API) is still in beta version. The finds here shows that the basic functions are trustworthy. Results pointed out that Landsat can recognize change in the spectral resolution clearly only for the first settlement. The ongoing modifications vary for each case. Overall, Landsat demonstrated high limitations, but need more investigations and may be used, with restriction, as a support of VHRSI
Is there a relation between environmental exposure to teratogenic substances during pregnancy and congenital anomalies in the newborn? A pilot study in Portugal
Background: Maternal occupation as a proxy of environmental exposure has been consistently associated with specific congenital anomalies (CA) in the foetus and newborn. On the other hand, geographical location of the mother such as place of residence and place of work have not been used as proxy for environmental exposures during pregnancy. We designed a pilot study aiming to investigate the association between maternal place of residence and workplace during pregnancy and CA in Portugal. Methods: Cases and controls are identified in the maternity unit. Cases are all live births with at least one CA delivered in the Barreiro hospital located in a heavy industrial area near Lisboa. Controls are the two normal births following each case. Residents outside the study area, stillbirths and women who decline to participate or are incapable of giving consent are excluded. A health professional interviews the mothers using a questionnaire adapted from the registry form of the Portuguese national registry of CA and includes information on places during pregnancy (residence, workplace, leisure), and demographic characterization as place of birth, infant sex, weight, description of CA, age of mother, ethnicity, maternal birth place. Maternal health and obstetric history, education, smoking, alcohol, drugs and medication use is also collected as potential confounders. Results: The pilot study started in January 2016 and at the moment two cases and four controls have been recruited without refusals. The study will continue to be implemented and it is proposed to start in other hospital units during 2016
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