Observational Research on NCDs in HIV-Positive Populations: Conceptual and Methodological Considerations

: Noncommunicable diseases (NCDs) account for a growing burden of morbidity and mortality among people living with HIV in low- and middle-income countries (LMICs). HIV infection and antiretroviral therapy interact with NCD risk factors in complex ways, and research into this "web of causation" has so far been largely based on data from high-income countries. However, improving the understanding, treatment, and prevention of NCDs in LMICs requires region-specific evidence. Priority research areas include: (1) defining the burden of NCDs among people living with HIV, (2) understanding the impact of modifiable risk factors, (3) evaluating effective and efficient care strategies at individual and health systems levels, and (4) evaluating cost-effective prevention strategies. Meeting these needs will require observational data, both to inform the design of randomized trials and to replace trials that would be unethical or infeasible. Focusing on Sub-Saharan Africa, we discuss data resources currently available to inform this effort and consider key limitations and methodological challenges. Existing data resources often lack population-based samples; HIV-negative, HIV-positive, and antiretroviral therapy-naive comparison groups; and measurements of key NCD risk factors and outcomes. Other challenges include loss to follow-up, competing risk of death, incomplete outcome ascertainment and measurement of factors affecting clinical decision making, and the need to control for (time-dependent) confounding. We review these challenges and discuss strategies for overcoming them through augmented data collection and appropriate analysis. We conclude with recommendations to improve the quality of data and analyses available to inform the response to HIV and NCD comorbidity in LMICs.

Methodological guidelines for reusing general ontologies

Currently, there is a great deal of well-founded explicit knowledge formalizing general notions, such as time concepts and the part_of relation. Yet, it is often the case that instead of reusing ontologies that implement such notions (the so-called general ontologies), engineers create procedural programs that implicitly implement this knowledge. They do not save time and code by reusing explicit knowledge, and devote effort to solve problems that other people have already adequately solved. Consequently, we have developed a methodology that helps engineers to: (a) identify the type of general ontology to be reused; (b) find out which axioms and definitions should be reused; (c) make a decision, using formal concept analysis, on what general ontology is going to be reused; and (d) adapt and integrate the selected general ontology in the domain ontology to be developed. To illustrate our approach we have employed use-cases. For each use case, we provide a set of heuristics with examples. Each of these heuristics has been tested in either OWL or Prolog. Our methodology has been applied to develop a pharmaceutical product ontology. Additionally, we have carried out a controlled experiment with graduated students doing a MCs in Artificial Intelligence. This experiment has yielded some interesting findings concerning what kind of features the future extensions of the methodology should have.

Fundamental Rights of workers in the Digital Age: A methodological approach from a case study. WP C.S.D.L.E. "Massimo D'Antona" .INT - 89/2011

The relationship between employer and worker is not only obligatory but above all, as Sinzheimer said, a ‘relationship of power’. In the Digital Age this statement is confirmed by the massive introduction of ICT in most of the companies that increase, in practice, employer’s supervisory powers. This is a worrying issue for two reasons: on one hand, ICT emerge as a new way to weaken the effectiveness of fundamental rights and the right to dignity of workers; and, on the other hand, Spanish legal system does not offer appropriate solutions to ensure that efficacy. Moreover, in a scenario characterized by a hybridization of legal systems models –in which traditional hard law methods are combined with soft law and self regulation instruments–, the role of our case law has become very important in this issue. Nevertheless, despite the increase of judicialization undergone, solutions offered by Courts are so different that do not give enough legal certainty. Facing this situation, I suggest a methodological approach –using Alchourron and Bulygin’s normative systems theory and Alexy’s fundamental rights theory– which can open new spaces of decision to legal operators in order to solve properly these problems. This proposal can allow setting a policy that guarantees fundamental rights of workers, deepening their human freedom in companies from the Esping-Andersen’s de-commodification perspective. With this purpose, I examine electronic communications in the company as a case study.

Some problems with life event lists and health outcomes

Lists of life events are widely used in health outcomes research. As part of a large cohort study of women's health in Australia, age- and gender-specific life events lists were developed and administered to women in different age groups over time. In this article, we provide empirical evidence that recall of life events is subject to telescoping (i.e., remote events are reported to have occurred more recently) and to mood (women with lower mental health scores report more life events, especially perceived rather than factual events). Nevertheless, even after adjustment for confounders, there is a clear association between poorer physical health and more life events. Therefore, these results demonstrate a continuing need for lists of life events in health research but also highlight the methodological challenges in using them.

The MIMIC model and formative variables:problems and solutions

The use of the multiple indicators, multiple causes model to operationalize formative variables (the formative MIMIC model) is advocated in the methodological literature. Yet, contrary to popular belief, the formative MIMIC model does not provide a valid method of integrating formative variables into empirical studies and we recommend discarding it from formative models. Our arguments rest on the following observations. First, much formative variable literature appears to conceptualize a causal structure between the formative variable and its indicators which can be tested or estimated. We demonstrate that this assumption is illogical, that a formative variable is simply a researcher-defined composite of sub-dimensions, and that such tests and estimates are unnecessary. Second, despite this, researchers often use the formative MIMIC model as a means to include formative variables in their models and to estimate the magnitude of linkages between formative variables and their indicators. However, the formative MIMIC model cannot provide this information since it is simply a model in which a common factor is predicted by some exogenous variables—the model does not integrate within it a formative variable. Empirical results from such studies need reassessing, since their interpretation may lead to inaccurate theoretical insights and the development of untested recommendations to managers. Finally, the use of the formative MIMIC model can foster fuzzy conceptualizations of variables, particularly since it can erroneously encourage the view that a single focal variable is measured with formative and reflective indicators. We explain these interlinked arguments in more detail and provide a set of recommendations for researchers to consider when dealing with formative variables.

Longitudinal effects of family factors on alcohol use and alcohol-related problems among males from pre-adolescence to adulthood

The goal of this study was to examine the longitudinal effects of five family factors on alcohol use among adolescent males. The family factors included familism (family pride, loyalty, and cohesion), parent derogation (being put down by parents), parent/child communication, family alcohol problems and family drug problems. The study focused on the effects of the family factors reported by a sample of 451 White-non-Hispanic and African American males during early and mid-adolescence on (1) the intensity of alcohol use in mid-adolescence, and (2) the number of problems associated with alcohol use during the transition to young adulthood. The study also explored racial differences in the effects of the family factors. The data for this study were derived from a two-phase longitudinal epidemiologic cohort study of male and female adolescents enrolled in middle schools in Miami, FL. Data were collected at four points between 1990 and 2001. Linear and logistical regressions were used to analyze the effects of the family variables on the dependent variables. ^ The results of the analyses indicated that all of the family variables except family drug problems were statistically significant predictors of the level of alcohol use and alcohol-related problems. Familism had a moderate influence on both of the dependent variables at all data points, while parent derogation, parent/child communication and family alcohol problems were weak predictors. While the family factors varied by race, their impact on the dependent variables did not vary substantially. ^ This study had methodological shortcomings related to measurement and design that may have contributed to the weak influence of the variables. Future studies should explore possible mediating effects of these variables, and should employ more sensitive measures that are culturally appropriate. The results suggest that, since early family factors have long-term effects on children's substance-using behaviors, the family environment should be addressed in prevention and intervention efforts. ^

A diagnostic framework for demand amplification problems in supply chains

This dissertation delivers a framework to diagnose the Bull-Whip Effect (BWE) in supply chains and then identify methods to minimize it. Such a framework is needed because in spite of the significant amount of literature discussing the bull-whip effect, many companies continue to experience the wide variations in demand that are indicative of the bull-whip effect. While the theory and knowledge of the bull-whip effect is well established, there still is the lack of an engineering framework and method to systematically identify the problem, diagnose its causes, and identify remedies. ^ The present work seeks to fill this gap by providing a holistic, systems perspective to bull-whip identification and diagnosis. The framework employs the SCOR reference model to examine the supply chain processes with a baseline measure of demand amplification. Then, research of the supply chain structural and behavioral features is conducted by means of the system dynamics modeling method. ^ The contribution of the diagnostic framework, is called Demand Amplification Protocol (DAMP), relies not only on the improvement of existent methods but also contributes with original developments introduced to accomplish successful diagnosis. DAMP contributes a comprehensive methodology that captures the dynamic complexities of supply chain processes. The method also contributes a BWE measurement method that is suitable for actual supply chains because of its low data requirements, and introduces a BWE scorecard for relating established causes to a central BWE metric. In addition, the dissertation makes a methodological contribution to the analysis of system dynamic models with a technique for statistical screening called SS-Opt, which determines the inputs with the greatest impact on the bull-whip effect by means of perturbation analysis and subsequent multivariate optimization. The dissertation describes the implementation of the DAMP framework in an actual case study that exposes the approach, analysis, results and conclusions. The case study suggests a balanced solution between costs and demand amplification can better serve both firms and supply chain interests. Insights pinpoint to supplier network redesign, postponement in manufacturing operations and collaborative forecasting agreements with main distributors.^

Alcohol-Related Problems in Eastern Europe : A Comparative Perspective

This thesis investigates the association between alcohol consumption and alcohol-related harm in Eastern Europe. The main aim was to estimate to what extent changes in per capita alcohol consumption have an impact on different forms of alcohol-related mortality, and to put the results in an international comparative perspective. The thesis includes four papers; the first two papers use aggregate time-series analysis to assess how changes in per capita consumption affect rates in suicide mortality and fatal non-intentional injuries in several Eastern European countries, respectively. The third paper applies the same methodological approach to analyse the population-level relationship between alcohol and homicide in Russia and the U.S.. The fourth paper employs survey data to assess how the risk of experiencing alcohol-related problems in relation to volume of consumption in the Baltic countries compares to Sweden and Italy. The results of the first three papers suggests: (i) that changes in per capita consumption are significantly related to changes in mortality rates of suicide, non-intentional injuries and homicide in the countries under study; (ii) that the relationship is stronger for men than for women, and (iii) that the relationship tends to be stronger in the countries with more detrimental drinking patterns, e.g. Russia. The results of the fourth paper suggest that the risk of experiencing alcohol-related problems in relation to level of drinking in the Baltic countries is similar to the corresponding risk in Sweden, but considerably stronger than in Italy. In conclusion, the findings support the significance of a public health approach to alcohol-related problems in Eastern Europe, i.e., policy measures directed towards total alcohol consumption. In addition, strategies aimed at reducing the occurrence of binge drinking seem to have great potential for reducing alcohol-related harm and mortality in Eastern European countries.