Ensemble transcript interaction networks: A case study on Alzheimer's disease

Systems biology techniques are a topic of recent interest within the neurological field. Computational intelligence (CI) addresses this holistic perspective by means of consensus or ensemble techniques ultimately capable of uncovering new and relevant findings. In this paper, we propose the application of a CI approach based on ensemble Bayesian network classifiers and multivariate feature subset selection to induce probabilistic dependences that could match or unveil biological relationships. The research focuses on the analysis of high-throughput Alzheimer's disease (AD) transcript profiling. The analysis is conducted from two perspectives. First, we compare the expression profiles of hippocampus subregion entorhinal cortex (EC) samples of AD patients and controls. Second, we use the ensemble approach to study four types of samples: EC and dentate gyrus (DG) samples from both patients and controls. Results disclose transcript interaction networks with remarkable structures and genes not directly related to AD by previous studies. The ensemble is able to identify a variety of transcripts that play key roles in other neurological pathologies. Classical statistical assessment by means of non-parametric tests confirms the relevance of the majority of the transcripts. The ensemble approach pinpoints key metabolic mechanisms that could lead to new findings in the pathogenesis and development of AD

Evolution and treatment of vitamin B12 deficiency as a risk factor for (cognitive and functional) neurodegenerative diseases in institutionalized elderly = Evolución y tratamiento de la deficiencia de vitamina B12 como factor de riesgo de enfermedades neurodegenerativas (cognitivas y funcionales) en las personas mayores institucionalizadas.

Prevalence of vitamin B12 deficiency is very common in elderly people and can reach values as high as 40.5% of the population. It can be the result of the interaction among several factors. Vitamin B12 deficiencies have been associated with neurological, cognitive deterioration, haematological abnormalities and cardiovascular diseases that have an important influence on the health of the elderly and their quality of life. It is necessary to approach the problems arisen from the lack of data relative to them. The main objective of this thesis was to analyse the evolution of vitamin B12 status and related parameters, lipid and haematological profiles and their relationship to health risk factors, and to functional and cognitive status over one year and to determine the effect of an oral supplementation of 500 μg of cyanocobalamin for a short period of 28 days. An additional objective was to analyze the possible effects of medicine intakes on vitamin B status. Three studies were performed: a) a one year longitudinal follow-up with four measure points; b) an intervention study providing an oral liquid supplement of 500 μg of cyanocobalamin for a 28 days period; and c) analysis of the possible effect of medication intake on vitamin B status using the ATC classification of medicines. The participants for these studies were recruited from nursing homes for the elderly in the Region of Madrid. Sixty elders (mean age 84 _ 7y, 19 men and 41 women) were recruited for Study I and 64 elders (mean age 82 _ 7y, 24 men and 40 women) for Study II. For Study III, baseline data from the initially recruited participants of the first two studies were used. An informed consent was obtained from all participants or their mentors. The studies were approved by the Ethical Committee of the University of Granada. Blood samples were obtained at each examination date and were analyzed for serum cobalamin, holoTC, serum and RBC folate and total homocysteine according to laboratory standard procedures. The haematological parameters analyzed were haematocrit, haemoglobin and MCV. For the lipid profile TG, total cholesterol, LDL- and HDLcholesterol were analyzed. Anthropometric measures (BMI, skinfolds [triceps and subscapular], waist girth and waist to hip ratio), functional tests (hand grip, arm and leg strength tests, static balance) and MMSE were obtained or administered by trained personal. The vitamin B12 supplement of Study II was administered with breakfast and the medication intake was taken from the residents’ anamnesis. Data were analyzed by parametric and non-parametric statistics depending on the obtained data. Comparisons were done using the appropriate ANOVAs or non-parametric tests. Pearsons’ partial correlations with the variable “time” as control were used to define the association of the analyzed parameters. XIII The results showed that: A) Over one year, in relationship to vitamin B status, serum cobalamin decreased, serum folate and mean corpuscular volumen increased significantly and total homocysteine concentrations were stable. Regarding blood lipid profile, triglycerides increased and HDL-cholesterol decreased significantly. Regarding selected anthropometric measurements, waist circumference increased significantly. No significant changes were observed for the rest of parameters. B) Prevalence of hyperhomocysteinemia was high in the elderly studied, ranging from 60% to 90 % over the year depending on the cut-off used for the classification. LDL-cholesterol values were high, especially among women, and showed a tendency to increase over the year. Results of the balance test showed a deficiency and a tendency to decrease; this indicates that the population studied is at high risk for falls. Lower extremity muscular function was deficient and showed a tendency to decrease. A highly significant relationship was observed between the skinfold of the triceps and blood lipid profile. C) Low cobalamin concentrations correlated significantly with low MMSE scores in the elderly studied. No correlations were observed between vitamin B12 status and functional parameters. D) Regarding vitamin B12 status, holo-transcobalamin seems to be more sensitive for diagnosis; 5-10% of the elderly had a deficiency using serum cobalamin as a criterion, and 45-52% had a deficiency when using serum holotranscobalamin as a criterion. E) 500 μg of cyanocobalamin administered orally during 28 days significantly improved vitamin B12 status and significantly decreased total homocysteine concentrations in institutionalized elderly. No effect of the intervention was observed on functional and cognitive parameters. F) The relative change (%) of improvement of vitamin B12 status was higher when using serum holo-transcobalamin as a criterion than serum cobalamin. G) Antiaenemic drug intake normalized cobalamin, urologic drugs and corticosteroids serum folate, and psychoanaleptics holo-transcobalamin levels. Drugs treating pulmonary obstruction increased total homocysteine concentration significantly. H) The daily mean drug intake was 5.1. Fiftynine percent of the elderly took medication belonging to 5 or more different ATC groups. The most prevalent were psycholeptic (53%), antiacid (53%) and antithrombotic (47%) drugs.

Desarrollo de un método estadístico para la generación de escenarios climáticos de alta resolución a partir de simulaciones de baja resolución de Modelos de Circulación General: aplicación a España

Esta tesis doctoral presenta el desarrollo, verificación y aplicación de un método original de regionalización estadística para generar escenarios locales de clima futuro de temperatura y precipitación diarias, que combina dos pasos. El primer paso es un método de análogos: los "n" días cuya configuración atmosférica de baja resolución es más parecida a la del día problema, se seleccionan de un banco de datos de referencia del pasado. En el segundo paso, se realiza un análisis de regresión múltiple sobre los "n" días más análogos para la temperatura, mientras que para la precipitación se utiliza la distribución de probabilidad de esos "n" días análogos para obtener la estima de precipitación. La verificación de este método se ha llevado a cabo para la España peninsular y las Islas Baleares. Los resultados muestran unas buenas prestaciones para temperatura (BIAS cerca de 0.1ºC y media de errores absolutos alrededor de 1.9ºC); y unas prestaciones aceptables para la precipitación (BIAS razonablemente bajo con una media de -18%; error medio absoluto menor que para una simulación de referencia (la persistencia); y una distribución de probabilidad simulada similar a la observada según dos test no-paramétricos de similitud). Para mostrar la aplicabilidad de la metodología desarrollada, se ha aplicado en detalle en un caso de estudio. El método se aplicó a cuatro modelos climáticos bajo diferentes escenarios futuros de emisiones de gases de efecto invernadero, para la región de Aragón, produciendo así proyecciones futuras de precipitación y temperaturas máximas y mínimas diarias. La fiabilidad de la técnica de regionalización fue evaluada de nuevo para el caso de estudio mediante un proceso de verificación. Para determinar la capacidad de los modelos climáticos para simular el clima real, sus simulaciones del pasado (la denominada salida 20C3M) se regionalizaron y luego se compararon con el clima observado (los resultados son bastante robustos para la temperatura y menos concluyentes para la precipitación). Las proyecciones futuras a escala local presentan un aumento significativo durante todo el siglo XXI de las temperaturas máximas y mínimas para todos los futuros escenarios de emisiones considerados. Las simulaciones de precipitación presentan mayores incertidumbres. Además, la aplicabilidad práctica del método se demostró también mediante su utilización para producir escenarios climáticos futuros para otros casos de estudio en los distintos sectores y regiones del mundo. Se ha prestado especial atención a una aplicación en Centroamérica, una región que ya está sufriendo importantes impactos del cambio climático y que tiene un clima muy diferente. ABSTRACT This doctoral thesis presents the development, verification and application of an original downscaling method for daily temperature and precipitation, which combines two statistical approaches. The first step is an analogue approach: the “n” days most similar to the day to be downscaled are selected. In the second step, a multiple regression analysis using the “n” most analogous days is performed for temperature, whereas for precipitation the probability distribution of the “n” analogous days is used to obtain the amount of precipitation. Verification of this method has been carried out for the Spanish Iberian Peninsula and the Balearic Islands. Results show good performance for temperature (BIAS close to 0.1ºC and Mean Absolute Errors around 1.9ºC); and an acceptable skill for precipitation (reasonably low BIAS with a mean of - 18%, Mean Absolute Error lower than for a reference simulation, i.e. persistence, and a well-simulated probability distribution according to two non-parametric tests of similarity). To show the applicability of the method, a study case has been analyzed. The method was applied to four climate models under different future emission scenarios for the region of Aragón, thus producing future projections of daily precipitation and maximum and minimum temperatures. The reliability of the downscaling technique was re-assessed for the study case by a verification process. To determine the ability of the climate models to simulate the real climate, their simulations of the past (the 20C3M output) were downscaled and then compared with the observed climate – the results are quite robust for temperature and less conclusive for the precipitation. The downscaled future projections exhibit a significant increase during the entire 21st century of the maximum and minimum temperatures for all the considered future emission scenarios. Precipitation simulations exhibit greater uncertainties. Furthermore, the practical applicability of the method was demonstrated also by using it to produce future climate scenarios for some other study cases in different sectors and regions of the world. Special attention was paid to an application of the method in Central America, a region that is already suffering from significant climate change impacts and that has a very different climate from others where the method was previously applied.

Injury incidence in judokas at the Spanish National University Championship

Background and Study Aim: Understanding injury incidence rates will be a great help with regards to preventing potential future damages. It is for this reason that this study suggests studying a large number of variables. The purpose of research is the relationship of events (empirical variables) that are usually taken into account in developing injury prevention programs during the battles and training in judo tournament. Material and methods: In this research project, 57 male judokas taking part in the Spanish National University Championship in 2009 were asked to complete a retrospective questionnaire. We analysed the following events: the most commonly injured body regions, the medical diagnosis, how and when the injury happened, the type of injury, the side of the body and the type of medical attention received. For the statistical analysis, we used the SPSS statistics programme to apply the Chi-square test in order to determine the significance levels for non-parametric tests from p<.05. Results: Significant differences were found in the most commonly injured body region, the shoulder/clavicle (p<.05), and in the most common diagnosis, the sprain (p<.05). Impact injuries (p<.05) are the most common and training (p<.05) is the most dangerous time. About the type of injury, 78.38% are new injuries (p<.05) and 69.05% affect the right hand side of the body (p<.05). Doctors are the most consulted specialists, but the physiotherapists obtained the best marks. Have been out due to injury for over 21 days 36.36% of the participants, but not for the entire season. Conclusions: The most common diagnosis in university student judokas coincides with those of elite judokas, with the sprain being the most common. University student judokas have a higher rate of shoulder/clavicle injuries, while professional judokas are prone to a higher rate of knee injuries. Training is the most common moment in which injuries occur, both in university student judokas and professional judokas. New injuries are the most common types of injuries in university student judokas and, while doctors are the most consulted specialists, the physiotherapists obtained the best marks.

O atendimento ao cliente como fator de diferenciação

A presente investigação pretende identificar os fatores que compõem a vantagem competitiva da cadeia de pronto-a-vestir Zara, contribuindo para a sua diferenciação do mercado. Pretende-se ainda perceber se esses fatores diferem de acordo com as caraterísticas sociodemográficas dos consumidores (idade, grau académico e rendimento), bem como se a frequência de realização de compras na loja influencia significativamente os fatores de diferenciação pela vantagem competitiva. Para tal, desenvolveu-se um estudo de caso, assente numa metodologia quantitativa, que contou com a aplicação de um questionário como método de recolha dos dados. O tratamento estatístico recorreu a técnicas descritivas e inferenciais como a análise fatorial e testes de comparação de médias. Os resultados demonstram haver quatro fatores que compõem a vantagem competitiva da Zara (atendimento, marca e produto, ambiente da loja e valor percebido), verificando-se uma influência maioritariamente do grau de escolaridade e da frequência de compras na loja.

O Risco Percebido e Coberto pelas Seguradoras

Os Portugueses desde imemoráveis tempos gostam de partir à descoberta de mundos novos, fazemo-lo pelas mais variadas razões, no entanto, neste trabalho iremos apenas analisar os riscos associados ao turismo de lazer. Os atentados de Nova Iorque em 11 Setembro 2001, Síndrome Respiratório Grave em HongKong em Fevereiro de 2003, o Tsunami no oceano Indico em Dezembro 2004, a erupção vulcânica na Islândia em Abril de 2010 ou os atentados de Paris em 13 de Novembro 2015, estas datas ficaram marcadas para sempre, lemos e relemos inúmeros depoimentos de pessoas que se encontravam de férias nestas cidades e pensamos e se fossemos nós? Os primeiros registos da atividade seguradora datam do ano 5.000 A.C. inicialmente seguravam transportes de mercadorias, hoje em dia podem cobrir “qualquer coisa”. Com a perceção dos riscos que hoje em dia podem ocorrer numa viagem, será que as Seguradoras estão preparadas para minimizar os mesmos? E qual a perceção dos riscos para quem viaja. Para o efeito realizou-se um estudo exploratório por suporte a uma amostra de conveniência que reuniu 152 observações. Análises descritivas e testes não paramétricos foram aplicados para definir quais os riscos mais percebidos e quais os que os turistas portugueses pretendem ver cobertos. Concluiu-se que as pessoas que dão maior importância aos Risco de Saúde e Financeiro são os que efetuam seguros de viagem, já as que dão maior importância aos Risco Equipamento, Risco Politico, Risco Psicológico e Risco de Satisfação são as que optam por não fazer seguro.

Is there a trade-off between quality and productivity? The case of diagnostic technologies in Portugal

The purpose of this paper is twofold: first, we compute quality-adjusted measures of productivity change for the three most important diagnostic technologies (i.e., the Computerised Tomography Scan, Electrocardiogram and Echocardiogram) in the major Portuguese hospitals. We use the Malmquist–Luenberger index, which allows to measure productivity growth while controlling for the quality of the production. Second, using non-parametric tests, we analyse whether the implementation of the Prospective Payment System may have had a positive impact on the movements of productivity over time. The results show that the PPS has helped hospitals to use these tools more efficiently and to improve their effectiveness.

Statnote 4: what if the data are not normal?

When testing the difference between two groups, if previous data indicate non-normality, then either transform the data if they comprise percentages, integers or scores or use a non-parametric test. If there is uncertainty whether the data are normally distributed, then deviations from normality are likely to be small if the data are measurements to three significant figures. Unless there is clear evidence that the distribution is non-normal, it is more efficient to use the conventional t-tests. It is poor statistical practice to carry out both the parametric and non-parametric tests on a set of data and then choose the result that is most convenient to the investigator!

Social and financial efficiency of Islamic microfinance institutions:a Data Envelopment Analysis application

Microfinance has been developed as alternative solution for global poverty alleviation effort in the last 30 years. Microfinance institution (MFI) has unique characteristic wherein they face double bottom line objectives of outreach to the poor and financial sustainability. This study proposes a two-stage analysis to measure Islamic Microfinance institutions (IMFIs) performance by comparing them to conventional MFIs. First, we develop a Data Envelopment Analysis (DEA) framework to measure MFIs' efficiency in its double bottom line objectives, i.e. in terms of social and financial efficiency. In the second stage non-parametric tests are used to compare the performance and identify factors that contribute to the efficiency of IMFIs and MFIs.

Análise de tendência e caracterização sazonal e interanual da evapotranspiração de referência para o sudoeste da amazônia brasileira: Acre, Brasil

The objective of this research was to investigate monthly climatological, seasonal, annual and interdecadal of the reference evapotranspiration (ETo) in Acre state in order to better understand its spatial and temporal variability and identify possible trends in the region. The study was conducted with data from Rio Branco municipalities, the state capital, Tarauacá and Cruzeiro do Sul considering a 30-year period (1985-2014), from monthly data from weather stations surface of the National Institute of Meteorology. The methodology was held, first, the consistency of meteorological data. Thus, it was made the gap filling in the time series by means of multivariate techniques. Subsequently were performed statistical tests trend (Mann-Kendall) and homogeneity, by Sen's estimator of the magnitude of this trend is estimated, as well as computational algorithms containing parametric and non-parametric tests for two samples to identify from that year the trend has become significant. Finally, analysis of variance technique (ANOVA) was adopted in order to verify whether there were significant differences in average annual evapotranspiration between locations. The indirect method of Penman-Montheith parameterized by FAO was used to calculate the ETo. The results of this work through examination of the descriptive statistics showed that the ETo the annual average was 3.80, 2.92 and 2.86 mm day-1 year, to Rio Branco, Tarauacá and Cruzeiro do Sul, respectively. Featuring quite remarkable seasonal pattern with a minimum in June and a maximum in October, with Rio Branco to town one with the strongest signal (amplitudes) on the other hand, the Southern Cross presented the highest variability among the studied locations. By ANOVA it was found that the average annual statistically different for a significance level of 1% between locations, but the annual average between Cruzeiro do Sul and Tarauacá no statistically significant differences. For the three locations, the 2000s was the one with the highest ETo values associated with warmer waters of the North Atlantic basin and the 80s to lower values, associated with cooler waters of this basin. By analyzing the Mann-kendall and Sen estimator test, there was a trend of increasing the seasonal reference evapotranspiration (fall, winter and spring) on the order of 0.11 mm per decade and that from the years of 1990, 1996 and 2001 became statistically significant to the localities of Cruzeiro do Sul Tarauacá and Rio Branco, respectively. For trend analysis of meteorological parameters was observed positive trend in the 5% level of significance, for average temperature, minimum temperature and solar radiation.

Estimativas, variabilidade e análise de tendência da evapotranspiração de referência em perímetros irrigados, no semiárido do nordeste brasileiro

The variability / climate change has generated great concern worldwide, is one of the major issues as global warming, which can is affecting the availability of water resources in irrigated perimeters. In the semiarid region of Northeastern Brazil it is known that there is a predominance of drought, but it is not enough known about trends in climate series of joint water loss by evaporation and transpiration (evapotranspiration). Therefore, this study aimed to analyze whether there is increase and / or decrease evidence in the regime of reference evapotranspiration (ETo), for the monthly, annual and interdecadal scales in irrigated polo towns of Juazeiro, BA (9 ° 24'S, 40 ° 26'W and 375,5m) and Petrolina, PE (09 ° 09'S, 40 ° 22'W and 376m), which is the main analysis objective. The daily meteorological data were provided by EMBRAPA Semiárido for the period from 01.01.1976 to 31.12.2014, estimated the daily ETo using the standard method of Penman-Monteith (EToPM) parameterized by Smith (1991). Other methods of more simplified estimatives were calculated and compared to EToPM, as the ones following: Solar Radiation (EToRS), Linacre (EToL), Hargreaves and Samani (EToHS) and the method of Class A pan (EToTCA). The main statistical analysis were non-parametric tests of homogeneity (Run), trend (Mann-kendall), magnitude of the trend (Sen) and early trend detection (Mann-Whitney). The statistical significance adopted was 5 and / or 1%. The Analysis of Variance - ANOVA was used to detect if there is a significant difference in mean interdecadal mean. For comparison between the methods of ETo, it were used the correlation test (r), the Student t test and Tukey levels of 5% significance. Finally, statistics Willmott et al. (1985) statistics was used to evaluate the concordance index and performance of simplified methods compared to the standard method. It obtained as main results that there was a decrease in the time series of EToPM in irrigated areas of Juazeiro, BA and Petrolina, PE, significant respectively at 1 and 5%, with an annual magnitude of -14.5 mm (Juazeiro) and -7.7 mm (Petrolina) and early trend in 1996. The methods which had better for better agreement with EToPM were EToRS with very good performance, in both locations, followed by the method of EToL with good performance (Juazeiro) and median (Petrolina). EToHS had the worst performance (bad) for both locations. It is suggested that this decrease of EToPM can be associated with the increase in irrigated agricultural areas and the construction of Sobradinho lake upstream of the perimeters.

Nonparametric Evaluation of Quantitative Traits in Population-Based Association Studies when the Genetic Model is Unknown

Statistical association between a single nucleotide polymorphism (SNP) genotype and a quantitative trait in genome-wide association studies is usually assessed using a linear regression model, or, in the case of non-normally distributed trait values, using the Kruskal-Wallis test. While linear regression models assume an additive mode of inheritance via equi-distant genotype scores, Kruskal-Wallis test merely tests global differences in trait values associated with the three genotype groups. Both approaches thus exhibit suboptimal power when the underlying inheritance mode is dominant or recessive. Furthermore, these tests do not perform well in the common situations when only a few trait values are available in a rare genotype category (disbalance), or when the values associated with the three genotype categories exhibit unequal variance (variance heterogeneity). We propose a maximum test based on Marcus-type multiple contrast test for relative effect sizes. This test allows model-specific testing of either dominant, additive or recessive mode of inheritance, and it is robust against variance heterogeneity. We show how to obtain mode-specific simultaneous confidence intervals for the relative effect sizes to aid in interpreting the biological relevance of the results. Further, we discuss the use of a related all-pairwise comparisons contrast test with range preserving confidence intervals as an alternative to Kruskal-Wallis heterogeneity test. We applied the proposed maximum test to the Bogalusa Heart Study dataset, and gained a remarkable increase in the power to detect association, particularly for rare genotypes. Our simulation study also demonstrated that the proposed non-parametric tests control family-wise error rate in the presence of non-normality and variance heterogeneity contrary to the standard parametric approaches. We provide a publicly available R library nparcomp that can be used to estimate simultaneous confidence intervals or compatible multiplicity-adjusted p-values associated with the proposed maximum test.

Comparing the performance of the EQ-5D-3L and the EQ-5D-5L in young Portuguese adults

Background Some studies have reported a ceiling effect in EQ-5D-3L, especially in healthy and/or young individuals. Recently, two further levels have been included in its measurement model (EQ-5D-5L). The purposes of this study were (1) to assess the properties of the EQ-5D-5L in comparison with the standard EQ-5D-3L in a sample of young adults, (2) to foreground the importance of collecting qualitative data to confirm, validate or refine the EQ-5D questionnaire items and (3) to raise questions pertaining to the wording in these questionnaire items. Methods The data used came from a sample of respondents aged 30 or under (n = 624). They completed both versions of the EQ-5D, which were compared in terms of feasibility, level of inconsistency and ceiling effect. Agreement between the instruments was assessed using correlation coefficients and Bland-Altman plots. Known-groups validity of the EQ-5D-5L was also assessed using non-parametric tests. The discriminative properties were compared using receiver operating characteristic curves. Finally, four interviews were conducted for retrospective reports to elicit respondents’ understanding and perceptions of the format, instructions, items, and responses. Results Quantitative results show a ceiling effect reduction of 25.3 % and a high level agreement between both indices. Known-groups validity was confirmed for the EQ-5D-5L. Explorative interviews indicated ambiguity and low degree of certainty in regards to conceptualizing differences between levels moderate-slight across three dimensions. Conclusions The EQ-5D-5L performed better than the EQ-5D-3L. However, the explorative interviews demonstrated several limitations in the EQ-5D questionnaire wording and high context-dependent answers point to lack of illnesses’ experience amongst young adults.

A medida e as escalas de avaliação da saúde das populações neonatais e pediátricas : estudo de simulação de Monte Carlo com variáveis ordinais

A investigação na área da saúde e a utilização dos seus resultados tem funcionado como base para a melhoria da qualidade de cuidados, exigindo dos profissionais de saúde conhecimentos na área específica onde desempenham funções, conhecimentos em metodologia de investigação que incluam as técnicas de observação, técnicas de recolha e análise de dados, para mais facilmente serem leitores capacitados dos resultados da investigação. Os profissionais de saúde são observadores privilegiados das respostas humanas à saúde e à doença, podendo contribuir para o desenvolvimento e bem-estar dos indivíduos muitas vezes em situações de grande vulnerabilidade. Em saúde infantil e pediatria o enfoque está nos cuidados centrados na família privilegiando-se o desenvolvimento harmonioso da criança e jovem, valorizando os resultados mensuráveis em saúde que permitam determinar a eficácia das intervenções e a qualidade de saúde e de vida. No contexto pediátrico realçamos as práticas baseadas na evidência, a importância atribuída à pesquisa e à aplicação dos resultados da investigação nas práticas clínicas, assim como o desenvolvimento de instrumentos de mensuração padronizados, nomeadamente as escalas de avaliação, de ampla utilização clínica, que facilitam a apreciação e avaliação do desenvolvimento e da saúde das crianças e jovens e resultem em ganhos em saúde. A observação de forma sistematizada das populações neonatais e pediátricas com escalas de avaliação tem vindo a aumentar, o que tem permitido um maior equilíbrio na avaliação das crianças e também uma observação baseada na teoria e nos resultados da investigação. Alguns destes aspetos serviram de base ao desenvolvimento deste trabalho que pretende dar resposta a 3 objetivos fundamentais. Para dar resposta ao primeiro objetivo, “Identificar na literatura científica, os testes estatísticos mais frequentemente utilizados pelos investigadores da área da saúde infantil e pediatria quando usam escalas de avaliação” foi feita uma revisão sistemática da literatura, que tinha como objetivo analisar artigos científicos cujos instrumentos de recolha de dados fossem escalas de avaliação, na área da saúde da criança e jovem, desenvolvidas com variáveis ordinais, e identificar os testes estatísticos aplicados com estas variáveis. A análise exploratória dos artigos permitiu-nos verificar que os investigadores utilizam diferentes instrumentos com diferentes formatos de medida ordinal (com 3, 4, 5, 7, 10 pontos) e tanto aplicam testes paramétricos como não paramétricos, ou os dois em simultâneo, com este tipo de variáveis, seja qual for a dimensão da amostra. A descrição da metodologia nem sempre explicita se são cumpridas as assunções dos testes. Os artigos consultados nem sempre fazem referência à distribuição de frequência das variáveis (simetria/assimetria) nem à magnitude das correlações entre os itens. A leitura desta bibliografia serviu de suporte à elaboração de dois artigos, um de revisão sistemática da literatura e outro de reflexão teórica. Apesar de terem sido encontradas algumas respostas às dúvidas com que os investigadores e os profissionais, que trabalham com estes instrumentos, se deparam, verifica-se a necessidade de desenvolver estudos de simulação que confirmem algumas situações reais e alguma teoria já existente, e trabalhem outros aspetos nos quais se possam enquadrar os cenários reais de forma a facilitar a tomada de decisão dos investigadores e clínicos que utilizam escalas de avaliação. Para dar resposta ao segundo objetivo “Comparar a performance, em termos de potência e probabilidade de erro de tipo I, das 4 estatísticas da MANOVA paramétrica com 2 estatísticas da MANOVA não paramétrica quando se utilizam variáveis ordinais correlacionadas, geradas aleatoriamente”, desenvolvemos um estudo de simulação, através do Método de Monte Carlo, efetuado no Software R. O delineamento do estudo de simulação incluiu um vetor com 3 variáveis dependentes, uma variável independente (fator com três grupos), escalas de avaliação com um formato de medida com 3, 4, 5, e 7 pontos, diferentes probabilidades marginais (p1 para distribuição simétrica, p2 para distribuição assimétrica positiva, p3 para distribuição assimétrica negativa e p4 para distribuição uniforme) em cada um dos três grupos, correlações de baixa, média e elevada magnitude (r=0.10, r=0.40, r=0.70, respetivamente), e seis dimensões de amostras (n=30, 60, 90, 120, 240, 300). A análise dos resultados permitiu dizer que a maior raiz de Roy foi a estatística que apresentou estimativas de probabilidade de erro de tipo I e de potência de teste mais elevadas. A potência dos testes apresenta comportamentos diferentes, dependendo da distribuição de frequência da resposta aos itens, da magnitude das correlações entre itens, da dimensão da amostra e do formato de medida da escala. Tendo por base a distribuição de frequência, considerámos três situações distintas: a primeira (com probabilidades marginais p1,p1,p4 e p4,p4,p1) em que as estimativas da potência eram muito baixas, nos diferentes cenários; a segunda situação (com probabilidades marginais p2,p3,p4; p1,p2,p3 e p2,p2,p3) em que a magnitude das potências é elevada, nas amostras com dimensão superior ou igual a 60 observações e nas escalas com 3, 4,5 pontos e potências de magnitude menos elevada nas escalas com 7 pontos, mas com a mesma ma magnitude nas amostras com dimensão igual a 120 observações, seja qual for o cenário; a terceira situação (com probabilidades marginais p1,p1,p2; p1,p2,p4; p2,p2,p1; p4,p4,p2 e p2,p2,p4) em que quanto maiores, a intensidade das correlações entre itens e o número de pontos da escala, e menor a dimensão das amostras, menor a potência dos testes, sendo o lambda de Wilks aplicado às ordens mais potente do que todas as outra s estatísticas da MANOVA, com valores imediatamente a seguir à maior raiz de Roy. No entanto, a magnitude das potências dos testes paramétricos e não paramétricos assemelha-se nas amostras com dimensão superior a 90 observações (com correlações de baixa e média magnitude), entre as variáveis dependentes nas escalas com 3, 4 e 5 pontos; e superiores a 240 observações, para correlações de baixa intensidade, nas escalas com 7 pontos. No estudo de simulação e tendo por base a distribuição de frequência, concluímos que na primeira situação de simulação e para os diferentes cenários, as potências são de baixa magnitude devido ao facto de a MANOVA não detetar diferenças entre grupos pela sua similaridade. Na segunda situação de simulação e para os diferentes cenários, a magnitude das potências é elevada em todos os cenários cuja dimensão da amostra seja superior a 60 observações, pelo que é possível aplicar testes paramétricos. Na terceira situação de simulação, e para os diferentes cenários quanto menor a dimensão da amostra e mais elevada a intensidade das correlações e o número de pontos da escala, menor a potência dos testes, sendo a magnitude das potências mais elevadas no teste de Wilks aplicado às ordens, seguido do traço de Pillai aplicado às ordens. No entanto, a magnitude das potências dos testes paramétricos e não paramétricos assemelha-se nas amostras com maior dimensão e correlações de baixa e média magnitude. Para dar resposta ao terceiro objetivo “Enquadrar os resultados da aplicação da MANOVA paramétrica e da MANOVA não paramétrica a dados reais provenientes de escalas de avaliação com um formato de medida com 3, 4, 5 e 7 pontos, nos resultados do estudo de simulação estatística” utilizaram-se dados reais que emergiram da observação de recém-nascidos com a escala de avaliação das competências para a alimentação oral, Early Feeding Skills (EFS), o risco de lesões da pele, com a Neonatal Skin Risk Assessment Scale (NSRAS), e a avaliação da independência funcional em crianças e jovens com espinha bífida, com a Functional Independence Measure (FIM). Para fazer a análise destas escalas foram realizadas 4 aplicações práticas que se enquadrassem nos cenários do estudo de simulação. A idade, o peso, e o nível de lesão medular foram as variáveis independentes escolhidas para selecionar os grupos, sendo os recém-nascidos agrupados por “classes de idade gestacional” e por “classes de peso” as crianças e jovens com espinha bífida por “classes etárias” e “níveis de lesão medular”. Verificou-se um bom enquadramento dos resultados com dados reais no estudo de simulação.

As sociedades de capital de risco em Portugal: Critérios adoptados no processo de tomada de decisão de investimento

Este estudo procura compreender a importância atribuída aos critérios utilizados pelas SCR portuguesas, na seleção e avaliação de projetos do tipo early-stage. Os dados utilizados foram recolhidos com recurso a questionário aplicado a 22 SCR portuguesas. Foram utilizadas técnicas de estatística descritiva, testes não paramétricos e análise de clusters. Concluiu-se que a personalidade e experiência do empreendedor e equipa de gestão são os critérios mais valorizados. As SCR com capital maioritariamente privado consideram mais importante o grupo de critérios relativo à personalidade do empreendedor e equipa de gestão do que as de capital maioritariamente público; e, as SCR que ainda não se internacionalizaram, consideram mais importantes o grupo de critérios relativos à personalidade do empreendedor e equipa de gestão e o grupo de critérios relativo aos aspetos financeiros, do que as SCR que se internacionalizaram. Na análise de clusters identificaram-se três grupos de SCR: Criadores de riqueza de forma sustentada; Monopolistas Impacientes; e, Ciumento. ABSTRACT: This study seeks to understand the relevance of the criteria used by the Portuguese VCs to select and assess early stage type projects. The data used for the study was collected through a questionnaire answered by 22 Portuguese VCs. We employed descriptive statistic techniques, non-parametric tests and cluster analysis. The conclusion of the study was that the personality and experience of an entrepreneur and of the management team are the most valued criteria. VCs with a majority of private share capital found the group of criteria related to the personality of the entrepreneur and of the management team to be more important than the companies with a majority of public share capital; additionally, the VCs that have not yet expanded internationally, consider the personality of the entrepreneur and management team and the group of criteria associated to financial aspects, to be more important than the VCs that have already expanded abroad. Throughout the study of the clusters we were able to identify three VCs groups: Creators of sustained wealth; Impatient Monopolists and Jealous.