Modelização de séries cronológicas multivariadas

Dissertação apresentada como requisito parcial para a obtenção do grau de Mestre em Métodos Matemáticos para Economia e Gestão de Empresas.A modelização de séries cronológicas multivariadas constitui o objecto do presente trabalho. A definição de conceitos específicos ao caso multivariado precede a análise das diferentes fases que constituem a metodologia conducente à modelização de uma qualquer série cronológica: Identificação, Estimação e Confirmação do Diagnóstico. Além disso é ainda analisada a utilização de um modelo em Previsão. Por outro lado, reservou-se o tratamento da fase da Identificação para o fim, conferindo-lhe primordial importância, uma vez que se pode considerar esta fase como a que constitui o principal desafio ao analista. Palavras-chave: simultaneidade; processo estocástico multivariado; série cronológica multivariada; matriz de covariância; matriz de correlação; matriz de correlação parcial; estacionaridade; modelos ARMA multivariados; estimação; verosimilhança exacta; verosimilhança aproximada; distribuição assintótica; consistência; confirmação do diagnóstico; resíduos de estimação; qualidade do ajustamento; previsão; previsor linear óptimo; identifiabilidade; redundância; identificação; modelos bivariados; matriz de correlação parcial q-condicionada estimada; matriz de correlação alargada estimada; estrutura sobreparametrizada; simplificação da estrutura identificada.The modelling of multivariate time series is the subject of this study. The definition of the concepts specifíc to the multivariate case precedes the analysis of the different phases comprising the methodology conducing to the modelling of a time series : Identification, Estimation , and Diagnostic Checking. In addition, the use of the model in Prediction is analyzed. Consideration of the Identification phase, however, was left to the last, stressing its importance, because precisely this aspect of the study is one which poses the greatest challenge to the analyst. Key-words: simultaneity; multivariate stochastic process; multivariate time series; covariance matrix; correlation matrix; partial correlation matrix; stationarity; multivariate ARMA models; estimation; exact likelihood; approximate likelihood; asymptotic distribution; consistence; diagnostic checking; estimation residuais; quality of fit; prediction; best linear predictior; identifiability; redundancy; identification; bivariate models; q-conditioned sample partial correlation matrix; extended sample correlation matrix; overparameterized structure; simplification of the identified structure.info:eu-repo/semantics/publishedVersio

Adaptation and Validation of the Individual Lifestyle Profile Scale of Portuguese Older Adults Living at Home

Abstract: (1) Background: Unadjusted lifestyles have been the main cause of risk for the loss of years of healthy life. However, currently valid and reliable instruments to assess the lifestyles of the elderly are quite long and difficult to interpret. For this reason, the objective of this study was to adapt and validate the ‘Individual Lifestyle Profile’ (ILP) scale in a sample of elderly people; (2) Methods: A methodological study was carried out and a sample of 300 older adults enrolled in a Health Unit located in the North of Portugal was used, who responded to the scale. We examined internal consistency, predictive validity, and discriminative ability; (3) Results: After the Exploratory Factorial analysis, a solution was found with four factors that explain a variance of 67.8%. The designation of the factors was changed from the original scale, with the exception of one dimension, and they were called Health Self-management, Social Participation and Group Interaction, Citizenship and Physical Activity. The total internal consistency (Cronbach’s alpha) was 0.858, ranging from 0.666 to 0.860 in the mentioned factors; (4) Conclusions: The ILP scale proved to be easy to apply and presented a good reliability and validity index, based on internal consistency, AFE and AFC. The scale allows evaluating the lifestyle of older adults, and its use will be aimed at modifying behaviors associated with negative lifestyles of older adults and their individual needs.info:eu-repo/semantics/publishedVersio

ATIVIDADES DE ENFERMAGEM QUE CONTRIBUEM PARA A QUALIDADE DOS CUIDADOS: ANÁLISE FATORIAL CONFIRMATÓRIA DA ESCALA

Objetivo: analisar a estrutura fatorial da Escala de Percepção das Atividades de Enfermagem que Contribuem para a Qualidade dos Cuidados. Método: estudo metodológico com participação de 3.451 enfermeiros de 36 hospitais portugueses. Além da realização da análise fatorial confirmatória, para avaliação da confiabilidade do modelo fatorial obtido, utilizou-se o alfa de Cronbach e a confiabilidade compósita. Resultados: os pesos fatoriais da solução encontrada foram majoritariamente elevados; os valores dos índices de ajustamento do modelo foram razoáveis; o alfa de Cronbach foi elevado para a totalidade da escala e para cinco dimensões, sendo aceitável em apenas uma dimensão. A confiabilidade compósita também foi elevada em cinco dimensões, excepto em uma, considerada como aceitável. Todas as atividades apresentaram uma confiabilidade individual elevada. Conclusão: em comparação com a escala original, o modelo fatorial identificado contempla seis dimensões e não sete, produzindo uma escala confiável e válida, passível de aplicação no contexto hospitalar.Descritores: Estudos de Validação. Análise Fatorial. Psicometria. Garantia da Qualidade dos Cuidados de Saúde.Cuidados de Enfermagem

Multidimensional Frailty and Lifestyles of Community-Dwelling Older Portuguese Adults

Abstract: (1) Background: Lifestyles are referred to as conditioning factors for the frailty of older adults. However, there are few studies that explore its association. The objective of the present study is to analyze the association between sociodemographic, clinical, and lifestyle factors of older adults people with multidimensional frailty. (2) Methods: Descriptive and correlational study carried out with older adults people registered in a Health Unit in Portugal. Data were collected through a sociodemographic and clinical questionnaire and application of the Individual Lifestyle Profile and Tilburg Frailty Index to assess the lifestyles and multidimensional frailty of older adults, respectively. This last instrument, being of a multidimensional nature, assesses not only physical, but also psychological and social frailty, with a cut-off point of 6. (3) Results: Of the 300 older adults who participated, most were female (60.3%) and had a mean age of 81.34 6.75 years. Moreover, 60.3% of the sample were frail older adults. Gender, marital status, number of household members, number of chronic diseases, number of daily medications, self-perception of health status and lifestyle and use of a walking device were associated with multidimensional frailty (p 0.001). Healthy eating habits, physical activity, relational behaviour, preventive behaviour, and stress management were significantly associated with lower physical, psychological, and social frailty (p 0.001). (4) Conclusions: When community health workers are aware of multidimensional frailty predictors and their components, they can intervene early and, consequently, delay the onset and progression of frailty in older adults.info:eu-repo/semantics/publishedVersio

Impact of COVID‐19 on professional nursing practice environments and patient safety culture

Aim: To analyse the impact of COVID-19 on professional nursing practice environments and patient safety culture. Background: The relationship between work environments and patient safety has been internationally recognized. In 2020, the pandemic imposed enormous challenges, yet the impact on these variables remains unknown. Method: This is a quantitative observational study, conducted in a Portuguese hospital, with 403 registered nurses. A self-completion questionnaire was used. Results: The impact on the Structure and Outcome components of nursing professional practice environments was positive. Although the Process component remained favourable to quality of care, a negative trend was confirmed in almost all dimensions. The results regarding safety culture showed weaknesses; ‘teamwork within units’ was the only dimension that maintained a positive culture. Conclusion: Positive responses regarding patient safety were significantly associated with the quality of the nursing professional practice environment. The need to invest in all dimensions of safety culture emerges to promote positive professional environments. Implications for nursing management: Improving professional nursing practice environments can be achieved through managers’ investment in the participation and involvement of nurses in the policies and functioning of institutions, as well as promoting an open, fair and participatory safety culture that encourages reporting events and provides adequate support for professionals.info:eu-repo/semantics/publishedVersio

The COVID-19 Pandemic and Professional Nursing Practice in the Context of Hospitals

The COVID-19 pandemic has imposed challenges to health systems and institutions, which had to quickly create conditions to meet the growing health needs of the population. Thus, this study aimed to assess the impact of COVID-19 on professional nursing practice environments and to identify the variables that affected their quality. Quantitative, observational study, conducted in 16 Portuguese hospitals, with 1575 nurses. Data were collected using a questionnaire and participants responded to two different moments in time: the pre-pandemic period and after the fourth critical period of COVID-19. The pandemic had a positive impact on the Structure and Outcome components, and a negative trend in the Process component. The variables associated with the qualification of the components and their dimensions were predominantly: work context, the exercise of functions in areas of assistance to COVID-19 patients, length of professional experience and length of experience in the service. The investment in professional practice environments impacted the improvement of organizational factors, supporting the development of nurses’ work towards the quality of care. However, it is necessary to invest in nurses’ participation, involvement and professional qualifications, which are aspects strongly dependent on the institutions’ management strategiesinfo:eu-repo/semantics/publishedVersio

Impact of COVID-19 on the Environments of Professional Nursing Practice and Nurses’ Job Satisfaction

(1) Background: The repercussions of work environments were widely studied before the pandemic. However, there are still many difficulties to be discovered considering the impact generated by it. Thus, this study aimed to analyse the impact of COVID-19 on nursing practice environments and nurses’ job satisfaction. (2) Methods: A correlational study was conducted in a hospital in northern Portugal, with the participation of 416 registered nurses. Data were collected in June 2021 through questionnaires. The study was approved by the Institutional Ethics Committee. (3) Results: COVID-19 had a favourable impact on the structure component of the practice environments; the process component decreased compared to the pre-pandemic period; the outcome component remained moderately favourable to the quality of care. Nurses were not very satisfied or not at all satisfied with their valuation and remuneration; moderately satisfied with the leadership and staffing; and satisfied with the organisation and resources, co-workers and valuation by patients and families. In more favourable environments, nurses’ job satisfactions were higher. (4) Conclusions: Identifying the dimensions with the best and worst scores allowed the institution’s managers to concentrate efforts on where improvements were needed, thus preparing professional contexts for the recovery of care activities

Environments of professional nursing practice in the context of the COVID-19 pandemic

Background: Although COVID-19 attracted attention to the environments of professional nursing practice, triggering a series of responses to address some of the most pressing problems, it is important to identify the size and scope of other weaknesses that have emerged. Methods: In an observational and cross-sectional study, using the Scale for the Evaluation of the Environment of Professional Nursing Practice, 752 nurses from a Portuguese university hospital, provided socio-demographic and professional data about the components structure, process and outcome of their professional nursing environment. Data collection took place from June 1–30, 2020, immediately after the first critical period of the COVID-19 pandemic in Portugal. Results: In the analysed environment of professional nursing practice, Process factors were favourable to the quality of care, while the Structure and Outcome factors had a moderately favourable effect. Structure factors related to work contexts (P < .001) and nursing functions in patient care areas with COVID-19 (P = .001). Process factors related significantly to work contexts (P < .001). A significant association was found between Outcome factors and work contexts (P < .001) and nursing functions in patient care areas with COVID-19 (P = .005). Conclusion: The environments of professional nursing practice in the hospital under study are moderately favourable to the quality of care. However, the need to invest in nurses’ participation, involvement and professional qualification is clear. Maintenance of a sustainable nursing workforce requires attention to be given to ensuring that practice environments are conducive to the quality of care and geared to promoting professional involvement and job satisfaction among nurses

From the first to the fourth critical period of COVID-19 ::what has changed in nursing practice environments in hospital settings?

Background : The COVID-19 pandemic reinforced the need to invest in nursing practice environments and health institutions were led to implement several changes. In this sense, this study aimed to analyze the impact of the changes that occurred in nursing practice environments between the first and fourth critical periods of the pandemic. Methods : Quantitative, observational study, conducted in a University Hospital, with the participation of 713 registered nurses. Data were collected through a questionnaire with sociodemographic and professional characterization and the Scale for the Environments Evaluation of Professional Nursing Practice, applied at two different points in time: from 1 to 30 June 2020 and from 15 August to 15 September 2021. Data were processed using descriptive and inferential statistics. Results : Overall, the pandemic had a positive impact on nursing practice environments. However, the Process component remained favourable to quality of care, while the Structure and Outcome components only moderately favourable. Nurses working in Medicine Department services showed lower scores in several dimensions of the Structure, Process and Outcome components. On the other hand, nurses working in areas caring for patients with COVID-19 showed higher scores in several dimensions of the Structure, Process and Outcome components. Conclusions : The pandemic had a positive impact on various dimensions of nursing practice environments, which denotes that regardless of the adversities and moments of crisis that may arise, investment in work environments will have positive repercussions. However, more investment is needed in Medicine Department services, which have historically been characterised by high workloads and structural conditions that make it difficult to promote positive and sustainable workplaces

Characterisation of microbial attack on archaeological bone

As part of an EU funded project to investigate the factors influencing bone preservation in the archaeological record, more than 250 bones from 41 archaeological sites in five countries spanning four climatic regions were studied for diagenetic alteration. Sites were selected to cover a range of environmental conditions and archaeological contexts. Microscopic and physical (mercury intrusion porosimetry) analyses of these bones revealed that the majority (68%) had suffered microbial attack. Furthermore, significant differences were found between animal and human bone in both the state of preservation and the type of microbial attack present. These differences in preservation might result from differences in early taphonomy of the bones. © 2003 Elsevier Science Ltd. All rights reserved