A mixed-methods analysis of micro-collaborative coding practices in OpenStack.

Technical collaboration between multiple contributors is a natural phenomenon in distributed open source software development projects. Macro-collaboration, where each code commit is attributed to a single collaborator, has been extensively studied in the research literature. This is much less the case for so-called micro-collaboration practices, in which multiple authors contribute to the same commit. To support such practices, GitLab and GitHub started supporting social coding mechanisms such as the "Co-Authored-By:" trailers in commit messages, which, in turn, enable to empirically study such micro-collaboration. In order to understand the mechanisms, benefits and limitations of micro-collaboration, this article provides an exemplar case study of collaboration practices in the OpenStack ecosystem. Following a mixed-method research approach we provide qualitative evidence through a thematic and content analysis of semi-structured interviews with 16 OpenStack contributors. We contrast their perception with quantitative evidence gained by statistical analysis of the git commit histories ( ∼ 1M commits) and Gerrit code review histories ( ∼ 631K change sets and ∼ 2M patch sets) of 1,804 OpenStack project repositories over a 9-year period. Our findings provide novel empirical insights to practitioners to promote micro-collaborative coding practices, and to academics to conduct further research towards understanding and automating the micro-collaboration process.

Time-series transcriptional profiling yields new perspectives on susceptibility to murine osteoarthritis.

OBJECTIVE: Chronological age is a powerful epidemiologic risk factor for osteoarthritis (OA), a multifactorial disease that is characterized by articular cartilage (AC) degradation. It is unclear from a molecular perspective how aging interacts with OA to produce this risk to AC integrity. To address this key question, we used in vivo time-course analysis of OA development and murine interstrain variability in natural susceptibility to OA to examine changes in non-OA-prone CBA mice versus OA-prone STR/Ort mice, which develop disease that bears significant histologic resemblance to human OA. Through global transcriptome profiling, we attempted to discover the molecular signature linked with both OA vulnerability and progression. METHODS: Affymetrix Mouse Gene 1.0 ST Array profiles were generated from AC samples derived from CBA and STR/Ort mice at 3 different ages, corresponding to the stages prior to, at, and late after the natural onset of OA in the STR/Ort mice. RESULTS: We found that the OA in STR/Ort mice exhibited a molecular phenotype resembling human OA, and we pinpointed a central role of NF-κB signaling and the emergence of an immune-related signature in OA cartilage over time. We discovered that, strikingly, young healthy AC has a highly expressed skeletal muscle gene expression program, which is switched off during maturation, but is intriguingly retained in AC during OA development in STR/Ort mice. CONCLUSION: This study is the first to show that AC chondrocytes share a high-abundance gene-expression program with skeletal muscle. We show that failure to switch this program off, as well as the restoration of this program, is associated with inappropriate expression of NF-κB signaling pathways, skeletal muscle-related genes, and induction and/or progression of OA.

Outcomes of transfemoral transcatheter aortic valve implantation (TAVI) and predictors of thirty-day major adverse cardiovascular events (MACE) and one-year mortality.

OBJECTIVE: TAVI is more frequently used to treat aortic stenosis with the mandate to have a low as possible rate of adverse events. We present our 30-day outcomes and one-year mortality and examine the factors associated with them. METHODS: A prospective evaluation was performed of all patients who underwent transfemoral TAVI in Nicosia General Hospital from January 2015 until March 2020. MACE were defined as cardiac death, disabling stroke, and/or major vascular complications (VC). Multiple logistic and Cox regression analyses were used to identify the factors associated with 30-day MACE and one-year mortality, respectively. RESULTS: A total of 235 TAVI procedures were performed (178 balloon-expandable, 57 self-expandable). Thirty-day outcomes were MACE: 4.3%, cardiovascular death: 2.1%, disabling stroke: 1.3%, major VC: 1.7%, and contrast induced nephropathy (CIN): 4.3%. There was a rate of 6.2% new pacemaker implantations and 0.9% of more than mild aortic valve regurgitation (AR) at 30 days. Mortality at one year was 15.1%. The balloon-expandable valves appear to have less new pacemakers, less mild AR, lower contrast volume used, and less days of hospitalization, while the self-expandable valves have lower post-procedural gradients. Low hemoglobulin, history of atrial fibrillation (AF), and lower BMI were predictors of 30-day MACE. Serum creatinine >2 mg/dL, history of AF, RVSP >60 mmHg and major VC are predictors of one-year mortality. CONCLUSION: We have shown excellent 30-day results with low incidence of adverse events for both the balloon-expandable and self-expandable valves. Clinical factors are the main predictors of both 30-day MACE and one-year mortality; major VC is a strong predictor of one-year mortality.