Contextual Sensitivity in Grounded Theory: The Role of Pilot Studies

Grounded Theory is an established methodological approach for context specific inductive theory building. The grounded nature of the methodology refers to these specific contexts from which emergent propositions are drawn. Thus, any grounded theory study requires not only theoretical sensitivity, but also a good insight on how to design the research in the human activity systems to be studied. The lack of this insight may result in inefficient theoretical sampling or even erroneous purposeful sampling. These problems would not necessarily be critical, as it could be argued that through the elliptical process that characterizes grounded theory, remedial loops would always bring the researcher to the core of the theory. However, these elliptical remedial processes can take very long periods of time and result in catastrophic delays in research projects. As a strategy, this paper discusses, contrasts and compares the use of pilot studies in four different grounded theory projects. Each pilot brought different insights about the context, resulting in changes of focus, guidance to improve data collection instruments and informing theoretical sampling. Additionally, as all four projects were undertaken by researchers with little experience of inductive approaches in general and grounded theory in particular, the pilot studies also served the purpose of training in interviewing, relating to interviewees, memoing, constant comparison and coding. This last outcome of the pilot study was actually not planned initially, but revealed itself to be a crucial success factor in the running of the projects. The paper concludes with a theoretical proposition for the concept of contextual sensitivity and for the inclusion of the pilot study in grounded theory research designs

Temperature dependence of the coercive field in single-domain particle systems

The magnetic properties of Cu97Co3 and Cu90Co10 granular alloys were measured over a wide temperature range (2 to 300K). The measurements show an unusual temperature dependence of the coercive field. A generalized model is proposed and explains well the experimental behavior over a wide temperature range. The coexistence of blocked and unblocked particles for a given temperature rises difficulties that are solved here by introducing a temperature dependent blocking temperature. An empirical factor gamma arise from the model and is directly related to the particle interactions. The proposed generalized model describes well the experimental results and can be applied to other single-domain particle system.Comment: 7 pages, 8 figures, revised version, accepted to Physical Review B on 29/04/200

Convergence insufficiency and accommodative insufficiency in children

Purpose: Convergence and accommodative insufficiency represent the main cause of complaints during close visual work and can reduce visual performance and comfort. Knowing their prevalence among schoolchildren is fundamental to define strategies for action. The purpose of this study was to estimate the frequency of these conditions in children in 5th and 6th school years in inland Portugal and to assess the impact that each visual condition has on their quality of life, based on the level of visual symptoms. Methods: a cross-sectional study was carried out with children enrolled in the 5th and 6th school years. 372 children (192 girls) were assessed, with average ages of 10.9 ± 0.9 years. Refractive error and binocular vision assessment, integrating accommodative parameters, were used to analyse the visual condition. Symptoms were quantified using the Portuguese version of the CISS (Convergence Insufficiency Symptom Survey). Results: The prevalence of definite Convergence Insufficiency (CI) in the children assessed was 2%. A prevalence of 6,8% could be considered if clinically significant CI (high suspect and definite categories) cases are accounted. In relation to Accommodative Insufficiency (AI), a frequency rate of 10% was recorded, with 3% of the evaluated children presenting AI and CI simultaneously. The symptoms score was higher in AI than in CI. Conclusions: A frequency of approximately 10% was found for each one of the visual syndromes, and it was verified that visual discomfort is common among teenagers who carry these conditions. In cases of asthenopia, such as headaches and loss of concentration, associated with near vision activities, there is a requirement to evaluate the quality of binocular vision.info:eu-repo/semantics/publishedVersio

Automatic human activity segmentation and labeling in RGBD videos

Human activity recognition has become one of the most active research topics in image processing and pattern recognition. Manual analysis of video is labour intensive, fatiguing, and error prone. Solving the problem of recognizing human activities from video can lead to improvements in several application fields like surveillance systems, human computer interfaces, sports video analysis, digital shopping assistants, video retrieval, gaming and health-care. This paper aims to recognize an action performed in a sequence of continuous actions recorded with a Kinect sensor based on the information about the position of the main skeleton joints. The typical approach is to use manually labeled data to perform supervised training. In this paper we propose a method to perform automatic temporal segmentation in order to separate the sequence in a set of actions. By measuring the amount of movement that occurs in each joint of the skeleton we are able to find temporal segments that represent the singular actions.We also proposed an automatic labeling method of human actions using a clustering algorithm on a subset of the available features.info:eu-repo/semantics/acceptedVersio

A nonlinear water level controller for reservoirs in cascade

In this paper, a strategy for the control of the water levels of a cascade of reservoirs is presented. This is achieved by operating a pumping station or discharge structures. The system is disturbed by reservoirs inflows resulting from rainfall-runoff events. Some examples of these systems are reservoirs that must be operated to satisfy navigation or leisure requirements or their operation during flood events. The presented controller reveals a good performance and has the advantage of being simple to implement. Moreover, it was proven that the described control law ensures asymptotic reference tracking, reaches several convergence rates, by tuning, and it allows the changing of the desired water levels reference values during the control process.FCT - Fundação para a Ciência e a Tecnologia (UIDB / 04047/2020

Produção de raízes finas em floresta sucessional no Nordeste paraense.

Este trabalho foi realizado no município de Castanhal, Apeú, onde está localizada a área de pesquisa do Projeto MANFLORA, situada na Estação Experimental da Universidade Federal Rural da Amazônia, e objetivou avaliar a resposta da produção de raízes finas à irrigação durante a época seca. Para a quantificação da produção de raízes finas utilizou-se o método ingrowth technique que consiste na captura de raízes através armadilhas cilíndricas de polietileno. Foram avaliadas duas frequências de coleta das armadilhas: bimensal (frequência F1) e quadrimensal (frequência F2). Os resultados obtidos de produção bimensal e quadrimensal de raízes indicaram que não houve influência significativa do tratamento (irrigação), mas sim da sazonalidade da precipitação pluviométrica.PIBIC-2011