Effort estimation of FLOSS projects: A study of the Linux kernel

This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2011 SpringerEmpirical research on Free/Libre/Open Source Software (FLOSS) has shown that developers tend to cluster around two main roles: “core” contributors differ from “peripheral” developers in terms of a larger number of responsibilities and a higher productivity pattern. A further, cross-cutting characterization of developers could be achieved by associating developers with “time slots”, and different patterns of activity and effort could be associated to such slots. Such analysis, if replicated, could be used not only to compare different FLOSS communities, and to evaluate their stability and maturity, but also to determine within projects, how the effort is distributed in a given period, and to estimate future needs with respect to key points in the software life-cycle (e.g., major releases). This study analyses the activity patterns within the Linux kernel project, at first focusing on the overall distribution of effort and activity within weeks and days; then, dividing each day into three 8-hour time slots, and focusing on effort and activity around major releases. Such analyses have the objective of evaluating effort, productivity and types of activity globally and around major releases. They enable a comparison of these releases and patterns of effort and activities with traditional software products and processes, and in turn, the identification of company-driven projects (i.e., working mainly during office hours) among FLOSS endeavors. The results of this research show that, overall, the effort within the Linux kernel community is constant (albeit at different levels) throughout the week, signalling the need of updated estimation models, different from those used in traditional 9am–5pm, Monday to Friday commercial companies. It also becomes evident that the activity before a release is vastly different from after a release, and that the changes show an increase in code complexity in specific time slots (notably in the late night hours), which will later require additional maintenance efforts

HIV Risk Behavior Self-Report Reliability at Different Recall Periods

Few studies have investigated the optimal length of recall period for self-report of sex and drug-use behaviors. This meta-analysis of 28 studies examined the test-retest reliability of three commonly used recall periods: 1, 3, and 6 months. All three recall periods demonstrated acceptable test-retest reliability, with the exception of recall of needle sharing behaviors and 6-months recall of some sex behaviors. For most sex behaviors, a recall period of 3 months was found to produce the most reliable data; however, 6 months was best for recalling number of sex partners. Overall, shorter periods were found to be more reliable for recall of drug-use behaviors, though the most reliable length of recall period varied for different types of drugs. Implications of the findings and future directions for research are discussed

Mechanisms and Clinical Implications of the Placebo Effect: Is There a Potential for the Elderly? A Mini-Review

In recent years, the placebo effect has been a topic of considerable interest both in the scientific and the clinical community. In this time, the placebo effect has evolved from being considered a nuisance in clinical and pharmacological research to becoming a neurobiological phenomenon worthy of scientific investigation in its own right. Recent research shows that placebo effects are genuine psychobiological events attributable to the overall therapeutic context, and that these effects can be robust in both laboratory and clinical settings. These psychosocially induced biochemical changes in a patient's brain and body may in turn affect the course of a disease and the response to a therapy. Here we summarize and discuss the current insights into placebo mechanisms and discuss the potentially widespread implications for research and clinical practice. Even though a systematic knowledge of placebo effects across the lifespan is lacking, we aim at highlighting specific aspects related to the care of elderly patients and those suffering from neurodegenerative diseases

Experiences of healing therapy in patients with irritable bowel syndrome and inflammatory bowel disease.

BACKGROUND The use and value of different complementary therapies requires investigation. In particular, qualitative research is required to understand the perceptions and experiences of patients who undergo healing therapy as one type of complementary therapy. The aim of this research is to consider patients perceptions and experiences following a course of healing therapy. METHODS Twenty two patients took part in this study. This included 13 patients with irritable bowel disease (3 male, 10 female, 47.6 ± 15.0 years), 6 patients with ulcerative colitis (3 male, 3 female, 48.5 ± 25.6 years) and 3 female patients with Crohn's Disease (45.0 ± 5.2 years). Each patient undertook a single semi-structured interview following a course of healing therapy. The data was analysed using a thematic analysis. RESULTS Three broad themes were identified from patient interviews (1) The understanding and expectation of healing (2) Experiences and reflection on healing (3) Impact and outcome of healing. The details of each theme are explored within the text, often revealing a unique experience of healing therapy. CONCLUSION Patients were open towards the benefits that could be attained by healing, although most patients were not sure what healing would entail. Some patients expected to be relaxed by the sessions. However, the most consistent reports were that patients experienced a relaxing sensation that was generated within the session and lasted for a time period after the sessions. In addition to this the healing appeared to be associated with patients feeling more tolerant of their symptoms. Patients valued the therapist and their input into the healing process. It should be noted however, that this report cannot consider the efficacy of the treatment. Further details and experiences are considered within the article, including one negative experience

Student engagement and performance: A weekly diary study on the role of openness

In the present study, we used a quantitative diary design to investigate within-person fluctuations in student engagement and performance. Specifically, we analyzed the impact of weekly personal and study resources on weekly student engagement, active learning behaviors, and performance. In addition, we investigated whether students high (vs. low) in trait Openness reacted differently to their weekly resources. The sample was composed of 45 first-year psychology students who filled in a questionnaire over 3 weeks; twice per week (N = 45 9 6 = 270 occasions)—during the days they had tutorial group meetings. The tutors evaluated each student’s active learning behaviors during these meetings. Results of hierarchical linear modeling analyses showed that study engagement fully mediated the relationship between personal resources and observed learning activities; study resources were indirectly positively related to learning activities through study engagement. In addition, observed learning activities were positively related to the course grade. As hypothesized, trait Openness strengthened the positive relationship between personal/study resources and study engagement. Our findings highlight the importance of fostering students’ engagement. We conclude with a discussion of the theoretical implications for education and suggestions for future research