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

Pragmatic Randomised Evaluation of Stable Thoracolumbar fracture treatment Outcomes (PRESTO): Study Protocol for a Randomised Controlled Feasibility Trial combined with a qualitative study and survey

Background A thoracolumbar fracture is the most common fracture of the spinal column. Where the fracture is not obviously stable or unstable, the optimal management is uncertain. There are variations between surgeons, treating centres and within the evidence base as to whether surgical or non-surgical approaches should be used. In addition, the boundaries of this zone of uncertainty for stability are unclear. This study has been designed in response to a NIHR HTA commissioning brief to assess the feasibility of undertaking a large-scale trial to evaluate the effectiveness of surgical and non-surgical treatments for thoracolumbar fractures without neurological deficit. Methods Assessment of feasibility will be addressed through three elements: a randomised external feasibility study, a national survey of surgeons and a qualitative study. The external feasibility study is a pragmatic, parallel group, randomised controlled trial comparing surgical fixation (intervention) versus non-surgical management (control). Recruitment will take place in three secondary care centres in the United Kingdom. The primary outcome is recruitment rate, defined as the proportion of eligible participants who are randomised. Further outcomes related to recruitment, randomisation, drop-out, cross-over, loss to follow-up, completeness of outcome data, study processes and details of the interventions delivered will be collected. The survey of surgeons and qualitative study of clinicians, recruiting staff and patients will enhance the feasibility study, enabling a broad overview of current practice in the field in addition to perceived facilitators and barriers to running a full-scale trial. Discussion PRESTO is a feasibility study which aims to inform methodology for a definitive trial comparing surgical fixation with non-surgical management for patients with stable thoracolumbar fractures. Trial registration The trial is registered with the International Standard Randomised Controlled Trial Register (ISRCTN 12094890). Date of registration was 22/02/2018 (http://www.isrctn.com/ISRCTN12094890). Keywords Thoracolumbar, fracture, surgical fixation, randomised controlled trial, qualitative, survey, feasibility, pilot

Phenotyping and susceptibility of established porcine cells lines to African Swine Fever Virus infection and viral production

African swine fever virus (ASFV) is a highly pathogenic, double-stranded DNA virus with a marked tropism for cells of the monocyte-macrophage lineage, affecting swine species and provoking severe economic losses and health threats. In the present study, four established porcine cell lines, IPAM-WT, IPAM-CD163, Câ2+ and WSL, were compared to porcine alveolar macrophage (PAM) in terms of surface marker phenotype, susceptibility to ASFV infection and virus production. The virulent ASFV Armenia/07, E70 or the naturally attenuated NHV/P68 strains were used as viral models. Cells expressed only low levels of specific receptors linked to the monocyte/macrophage lineage, with low levels of infection overall, with the exception of WSL, which showed more efficient production of strain NHV/P68 but not of strains E70 and Armenia/07.Kansas State University-CBMSO Contract #868 and by Ministerio de Ciencia e Innovación of Spain, BIO2013-46605Peer Reviewe