Communal resources in open source software development

Introduction: Virtual communities play an important role in innovation. The paper focuses on the particular form of collective action in virtual communities underlying as Open Source software development projects. Method: Building on resource mobilization theory and private-collective innovation, we propose a theory of collective action in innovative virtual communities. We identify three communal resources (reputation, control over technology and learning opportunities) that appear as a byproduct while developing open source software. Analysis:Constructs are derived from exiting literature. Empirical data from Freenet, an open source software project for peer-to-peer software, illustrates both the levels of involvement and the communal resources. Results & conclusions: Communal resources are able to solve the collective action dilemma for virtual communities. We show that they increase in value for individuals along with their involvement in the community

Carrots and Rainbows: Motivation and Social Practice in Open Source Software Development

Open source software (OSS) is a social and economic phenomenon that raises fundamental questions about the motivations of contributors to information systems development. Some developers are unpaid volunteers who seek to solve their own technical problems, while others create OSS as part of their employment contract. For the past 10 years, a substantial amount of academic work has theorized about and empirically examined developer motivations. We review this work and suggest considering motivation in terms of the values of the social practice in which developers participate. Based on the social philosophy of Alasdair MacIntyre, we construct a theoretical framework that expands our assumptions about individual motivation to include the idea of a long-term, value-informed quest beyond short-term rewards. This motivation-practice framework depicts how the social practice and its supporting institutions mediate between individual motivation and outcome. The framework contains three theoretical conjectures that seek to explain how collectively elaborated standards of excellence prompt developers to produce high-quality software, change institutions, and sustain OSS development. From the framework, we derive six concrete propositions and suggest a new research agenda on motivation in OSS

Validation of a clinical and genetic model for predicting severe COVID-19

Using nested case-control data from the Lifelines COVID-19 cohort, we undertook a validation study of a clinical and genetic model to predict the risk of severe COVID-19 in people with confirmed COVID-19 and in people with confirmed or self-reported COVID-19. The model performed well in terms of discrimination of cases and controls for all ages (area under the receiver operating characteristic curve (AUC) = 0.680 for confirmed COVID-19 and AUC = 0.689 for confirmed and self-reported COVID-19) and in the age group in which the model was developed (50 years and older; AUC = 0.658 for confirmed COVID-19 and AUC = 0.651 for confirmed and self-reported COVID-19). There was no evidence of over- or under-dispersion of risk scores but there was evidence of overall over-estimation of risk in all analyses (all P < 0.0001). In the light of large numbers of people worldwide remaining unvaccinated and continuing uncertainty regarding vaccine efficacy over time and against variants of concern, identification of people at high risk of severe COVID-19 may encourage the uptake of vaccinations (including boosters) and the use of non-pharmaceutical inventions

Electrical Detection and Magnetic-Field Control of Spin States in Phosphorus-Doped Silicon

Electron paramagnetic resonance of ensembles of phosphorus donors in silicon has been detected electrically with externally applied magnetic fields lower than 200 G. Because the spin Hamiltonian was dominated by the contact hyperfine term rather than by the Zeeman terms at such low magnetic fields, superposition states $\alpha{}| \uparrow \downarrow >+\beta{}| \downarrow \uparrow >$ and $-\beta{}| \uparrow \downarrow > + \alpha{}| \downarrow \uparrow >$ were formed between phosphorus electron and nuclear spins, and electron paramagnetic resonance transitions between these superposition states and $| \uparrow \uparrow >$ or $| \downarrow \downarrow >$ states are observed clearly. A continuous change of $\alpha{}$ and $\beta{}$ with the magnetic field was observed with a behavior fully consistent with theory of phosphorus donors in silicon.Comment: 6 pages, 5 figure

Meeting Physical Activity Guidelines During Pregnancy and Its Relationship With Low Back/Pelvic Girdle Pain

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Transport and recombination through weakly coupled localized spin pairs in semiconductors during coherent spin excitation

Semi-analytical predictions for the transients of spin-dependent transport and recombination rates through localized states in semiconductors during coherent electron spin excitation are made for the case of weakly spin-coupled charge carrier ensembles. The results show that the on-resonant Rabi frequency of electrically or optically detected spin-oscillation doubles abruptly as the strength of the resonant microwave field gamma B_1 exceeds the Larmor frequency separation within the pair of charge carrier states between which the transport or recombination transition takes place. For the case of a Larmor frequency separation of the order of gamma B_1 and arbitrary excitation frequencies, the charge carrier pairs exhibit four different nutation frequencies. From the calculations, a simple set of equations for the prediction of these frequencies is derived

Magnetization Switching of Single Magnetite Nanoparticles Monitored Optically

Magnetic nanomaterials record information as fast as picoseconds in computer memories but retain it for millions of years in ancient rocks. This exceedingly broad range of times is covered by hopping over a potential energy barrier through temperature, ultrafast optical excitation for demagnetization or magnetization manipulation, mechanical stress, or microwaves. As switching depends on nanoparticle size, shape, orientation, and material properties, only single-nanoparticle studies can eliminate ensemble heterogeneity. Here, we push the sensitivity of photothermal magnetic circular dichroism down to individual 20-nm magnetite nanoparticles. Single-particle magnetization curves display superparamagnetic to ferromagnetic behaviors, depending on size, shape, and orientation. Some nanoparticles undergo thermally activated switching on time scales of milliseconds to minutes. Surprisingly, the switching barrier appears to vary in time, leading to dynamical heterogeneity. Our observations will help to identify and eventually control the nanoscale parameters influencing the switching of magnetic nanoparticles, an important step for applications in many fields

The assessment of disability related to vision performance-based measure in diabetic retinopathy.

PURPOSE: To validate a third-generation performance-based measure of visual function titled Assessment of Disability Related to Vision (ADREV) in a study population of patients with diabetic retinopathy. DESIGN: Prospective, cross-sectional study. METHODS: Patients with nonproliferative or proliferative diabetic retinopathy, free from ocular comorbidity, were recruited from a single institute and completed the ADREV, the 25-Item National Eye Institute Visual Functioning Questionnaire (VFQ-25), and a clinical ophthalmic examination. Correlation, regression, and bootstrap analysis were conducted to determine the relationship between ADREV scoring and each of the study\u27s clinical and self-report measures of visual ability, while controlling for potential confounders. RESULTS: Ninety-one patients with diabetic retinopathy completed the study and analysis showed that the ADREV total and subscale scores shared a stronger relationship with the clinical measures of visual function than did the VFQ total and subscale scores. Regression analysis revealed that binocular visual acuity, contrast sensitivity, and better eye visual field were the best predictors of ADREV performance. CONCLUSIONS: The ADREV performance measure is a valid instrument for the assessment of disability related to vision in patients with diabetic retinopathy. Furthermore, the assessments provided by ADREV were more related to traditional clinical indicators of visual impairment than were the results of the self-report measure, specifically the VFQ-25

Roel of Morning versus Evening Chronotype on Insulin Sensitivity and Central Hemodynamics in Adults with Metabolic Syndrome

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