Evaluación de los retrasos en actividades de construcción utilizando redes Bayesianas: Caso de estudio / Delay assessment of construction site activities using Bayesian networks: Case study / Avaliação dos atrasos nas atividades de construção utilizando redes Bayesianas: Estudo de caso

RESUMEN Los retrasos en proyectos de construcción son atribuídos a la concurrencia de factores que afectan el buen desarrollo, y mitigarlos, constituye uno de los mayores desafios que afronta la industria, ya que requiere tener en cuenta la dependencia e incidencia integrada de ellos. El objetivo de este estudio fue evaluar la influencia de factores de retraso sobre la duración de actividades de construcción, a través de un método que emplee las redes Bayesianas. Siguiendo la metodologia de investigación basada en el diseno, y aplicando un caso de estudio, se propone un método que incluye cómo identificar los principales factores de retraso que afecten las actividades; cómo representar la influencia y dependencia de estos factores por medio de una red Bayesiana; y cómo estimar el nivel de influencia por medio de la simulación de la red. Los resultados de esta investigación muestran como la aplicación de una red Bayesiana se puede emplear como apoyo a los profesionales de obra para gestionar las actividades de construcción y tomar decisiones en la medida que se actualice la información de la red bayesiana.

ABSTRACT The concurrence of multiple factors adversely affects construction project performance, resulting in delays. Mitigating such factors is challenging for the industry because solutions must include dependence and influence. Hence, managers must consider their systemic and integrated influence on the construction process for tracking projects. This study aimed to evaluate the influence of delay factors on the duration of construction site activities using Bayesian network techniques. Based on the design-based research methodology and the application in a case study this study proposed a method that involves three steps. First, identifying the main delay factors affecting construction activities; second, designing an influencing model as a Bayesian network; and third, estimating the integrated influence of such factors by simulating the Bayesian network. The results showed how a Bayesian network could support the construction team in managing the construction-site activities and making decisions about the performance of the construction process.

RESUMO Atrasos nos projetos de construção são atribuídos à concorrência de múltiplos fatores que afetam o desenvolvimento adequado do projeto, e mitigá-los é um dos maiores desafios enfrentados pelo setor; pois requer levar em conta a incidência integrada dos mesmos. O objetivo deste estudo foi avaliar a influência de um grupo de fatores sobre a duração das atividades de construção, utilizando a técnica da rede Bayesiana. Seguindo a metodologia de pesquisa baseada em projeto, foram identificados os principais fatores de atraso que afetam as atividades de construção e as relações de causa e efeito foram modeladas para estimar sua influência sobre a duração das atividades de fundação de um projeto de construção. Os resultados desta pesquisa mostram como a aplicação de uma rede Bayesiana pode ser usada para apoiar os profissionais do local no gerenciamento das atividades de construção e na tomada de decisões relativas ao desenvolvimento do projeto, considerando a incerteza e os fatores que influenciam o desenvolvimento do projeto.

Absence of Neuroplastic Changes in the Bilateral H-Reflex Amplitude following Spinal Manipulation with Activator IV.

Background and Objectives: Chiropractic spinal manipulation is an alternative medical procedure for treating various spinal dysfunctions. Great interest exists in investigating its neuroplastic effects on the central nervous system. Previous studies have found contradictory results in relation to the neuroplastic changes in the H-reflex amplitude as a response to manual spinal manipulation. The discrepancies could be partly due to differences in the unilateral nature of these recordings and/or the variable force exerted in manual techniques applied by distinct chiropractors. Concerning the latter point, the variability in the performance of manual interventions may bias the determination of the significance of changes in H-reflex responses derived from spinal manipulation. To investigate such responses, a chiropractic device can be used to provide more precise and reproducible results. The current contribution aimed to examine whether spinal manipulation with an Activator IV instrument generates neuroplastic effects on the bilateral H-reflex amplitude in dancers and non-dancers. Materials and Methods: A radiograph verified spinal dysfunction in both groups of participants. Since there were significant differences between groups in the mean Hmax values of the H-reflex amplitude before spinal intervention, an assessment was made of the possible dependence of the effects of spinal manipulation with Activator IV on the basal conditions. Results: Ten sessions of spinal manipulation with Activator IV did not cause statistically significant changes in the bilateral H-reflex amplitude (measured as the Hmax/Mmax ratio) in either group. Furthermore, no significant difference was detected in the effects of spinal manipulation between groups, despite their distinct basal H-reflex amplitude. Conclusions: Regarding the therapeutic benefits of a chiropractic adjustment, herein carried out with Activator IV, the present findings suggest that the mechanism of action is not on the monosynaptic H-reflex pathway. Further research is needed to understand the mechanisms involved.

A review of Cyclospora cayetanensis in animals.

Cyclosporiasis is a global, emerging disease in humans caused by Cyclospora cayetanensis. The role of animals in the epidemiology of cyclosporiasis is not fully understood. We conducted a narrative review of the published literature on C. cayetanensis in animals. MEDLINE® (Web of Science™ ), Agricola (ProQuest), CABI Global Health (1979 to December 2020) and Food Science and Technology Abstracts (EBSCOhost) (1979 to February 2020) were searched. Studies of C. cayetanensis in or on any species of animal were eligible. Thirteen relevant studies were found. C. cayetanensis was found in wild and farmed Mediterranean mussels (Mytilus galloprovincialis), wild grooved carpet shell clams (Ruditapes decussatus) and in the faeces of dogs (domestic and street), wild chickens, wild rhesus macaques (Macaca mulatta), chimpanzees (Pan troglodytes) from a wildlife research centre, and Cynomolgus monkeys (Macaca fascicularis) from an experimental primate research centre. As the small intestines of the naturally exposed animals were not biopsied, existence of a natural animal reservoir of C. cayetanensis could not be confirmed. Animals shedding oocysts in their faeces may be paratenic hosts. Investigators were able to successfully infect the following animals with C. cayetanensis: oysters, Asian freshwater clams (Corbicula fluminea), Swiss albino mice and guinea pigs. Future non-laboratory studies of animals should use PCR coupled with DNA sequencing to confirm that the species found is C. cayetanensis. The potential role of animals in the transport of oocysts and contamination of food, water, and soil could be explored through future primary research.

Odds Ratio or Prevalence Ratio? An Overview of Reported Statistical Methods and Appropriateness of Interpretations in Cross-sectional Studies with Dichotomous Outcomes in Veterinary Medicine.

One of the most commonly observational study designs employed in veterinary is the cross-sectional study with binary outcomes. To measure an association with exposure, the use of prevalence ratios (PR) or odds ratios (OR) are possible. In human epidemiology, much has been discussed about the use of the OR exclusively for case-control studies and some authors reported that there is no good justification for fitting logistic regression when the prevalence of the disease is high, in which OR overestimate the PR. Nonetheless, interpretation of OR is difficult since confusing between risk and odds can lead to incorrect quantitative interpretation of data such as "the risk is X times greater," commonly reported in studies that use OR. The aims of this study were (1) to review articles with cross-sectional designs to assess the statistical method used and the appropriateness of the interpretation of the estimated measure of association and (2) to illustrate the use of alternative statistical methods that estimate PR directly. An overview of statistical methods and its interpretation using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was conducted and included a diverse set of peer-reviewed journals among the veterinary science field using PubMed as the search engine. From each article, the statistical method used and the appropriateness of the interpretation of the estimated measure of association were registered. Additionally, four alternative models for logistic regression that estimate directly PR were tested using our own dataset from a cross-sectional study on bovine viral diarrhea virus. The initial search strategy found 62 articles, in which 6 articles were excluded and therefore 56 studies were used for the overall analysis. The review showed that independent of the level of prevalence reported, 96% of articles employed logistic regression, thus estimating the OR. Results of the multivariate models indicated that logistic regression was the method that most overestimated the PR. The findings of this study indicate that although there are methods that directly estimate PR, many studies in veterinary science do not use these methods and misinterpret the OR estimated by the logistic regression.

Can hierarchical modeling improve our understanding of bovine abortion due to Neospora caninum infection?

The purpose of this study was to use mixed logistic regression to evaluate the association between Neospora caninum serostatus and abortion, accounting for the effects of farms. The main objective was to explore the interpretation of this model and discuss the contribution of this analysis to our understanding of the disease's epidemiology. A mixed-effects logistic model using farms as a random effect and the serostatus for N. caninum, age of cattle and farm location as fixed effects was performed. The data from 1256 cows over 15 months of age from 60 farms were used, and the abortion information was obtained from farm records. A significant association between N. caninum serostatus and abortion was found (p<0.0001). Seropositive cows had 6.63 times greater odds of having a history of previous abortion (95% CI: 4.35-13.37). There was remarkable variability across farms in the probability of a cow having a history of an abortion. Including the effects of the farms in the regression, it was possible to estimate an intraclass correlation coefficient (ICC) of 16%. That means that 16% of the variation in abortion occurrence that was not explained by the fixed effects was due to farms. In practical terms, this variation means that while there are farms with several seropositive cows and no/few abortion cases, the opposite is also true, with a high number of abortions in farms with low/medium seroprevalence. The remaining variability (84%) was not explained by the effect of N. caninum, age, region, and the effect of farms, i.e., it is due to unknown factors that are causing abortions. The results of this study reinforce the importance of N. caninum as a cause of abortions and demonstrate the significant heterogeneity in the probability of a cow having a history of an abortion that cannot be explained completely by N. caninum serostatus, age or location. Including the hierarchical structure of the population along with correct interpretation of the model estimates helps us understand the effect of the farms, i.e., the probability of a cow abortion conditional to the farms, which also contributes to our understanding of the epidemiology of abortions caused by neosporosis. The use of hierarchical models and reporting the ICC should be encouraged.