Assessing Code Authorship: The Case of the Linux Kernel

Code authorship is a key information in large-scale open source systems. Among others, it allows maintainers to assess division of work and identify key collaborators. Interestingly, open-source communities lack guidelines on how to manage authorship. This could be mitigated by setting to build an empirical body of knowledge on how authorship-related measures evolve in successful open-source communities. Towards that direction, we perform a case study on the Linux kernel. Our results show that: (a) only a small portion of developers (26 %) makes significant contributions to the code base; (b) the distribution of the number of files per author is highly skewed --- a small group of top authors (3 %) is responsible for hundreds of files, while most authors (75 %) are responsible for at most 11 files; (c) most authors (62 %) have a specialist profile; (d) authors with a high number of co-authorship connections tend to collaborate with others with less connections.Comment: Accepted at 13th International Conference on Open Source Systems (OSS). 12 page

SETD2 loss-of-function promotes renal cancer branched evolution through replication stress and impaired DNA repair

The research leading to these results is supported by Cancer Research UK (XYG, RAB, EG, PM, PE, SG, C Santos, AJR, NM, PAB, AS and C Swanton), Breast Cancer Research Foundation (C Swanton and NK), Medical Research Council (ID: G0902275 to MG and C Santos; ID: G0701935/2 to AJR and C Swanton), the Danish Cancer Society (AMM, J Bartkova and J Bartek), the Lundbeck Foundation (R93-A8990 to J Bartek), the Ministry of the interior of the Czech Republic (grant VG20102014001 to MM and J Bartek), the National Program of Sustainability (grant LO1304 to MM and J Bartek), the Danish Council for Independent Research (grant DFF-1331-00262 to J Bartek), NIHR RMH/ICR Biomedical Research Centre for Cancer (JL), the EC Framework 7 (PREDICT 259303 to XYG, EG, PM, MG, TJ and C Swanton; DDResponse 259892 to J Bartek and J Bartkova and RESPONSIFY ID:259303 to C Swanton), UCL Overseas Research Scholarship (SG). C Swanton is also supported by the European Research Council, Rosetrees Trust and The Prostate Cancer Foundation. This research is supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre

High-Pass Filtering of Input Signals by the Ih Current in a Non-Spiking Neuron, the Retinal Rod Bipolar Cell

Hyperpolarization–activated cyclic nucleotide–sensitive (HCN) channels mediate the If current in heart and Ih throughout the nervous system. In spiking neurons Ih participates primarily in different forms of rhythmic activity. Little is known, however, about its role in neurons operating with graded potentials as in the retina, where all four channel isoforms are expressed. Intriguing evidence for an involvement of Ih in early visual processing are the side effects reported, in dim light or darkness, by cardiac patients treated with HCN inhibitors. Moreover, electroretinographic recordings indicate that these drugs affect temporal processing in the outer retina. Here we analyzed the functional role of HCN channels in rod bipolar cells (RBCs) of the mouse. Perforated–patch recordings in the dark–adapted slice found that RBCs exhibit Ih, and that this is sensitive to the specific blocker ZD7288. RBC input impedance, explored by sinusoidal frequency–modulated current stimuli (0.1–30 Hz), displays band–pass behavior in the range of Ih activation. Theoretical modeling and pharmacological blockade demonstrate that high–pass filtering of input signals by Ih, in combination with low–pass filtering by passive properties, fully accounts for this frequency–tuning. Correcting for the depolarization introduced by shunting through the pipette–membrane seal, leads to predict that in darkness Ih is tonically active in RBCs and quickens their responses to dim light stimuli. Immunohistochemistry targeting candidate subunit isoforms HCN1–2, in combination with markers of RBCs (PKC) and rod–RBC synaptic contacts (bassoon, mGluR6, Kv1.3), suggests that RBCs express HCN2 on the tip of their dendrites. The functional properties conferred by Ih onto RBCs may contribute to shape the retina's light response and explain the visual side effects of HCN inhibitors

Software quality assurance: in large scale and complex software-intensive systems

Software Quality Assurance in Large Scale and Complex Software-intensive Systems presents novel and high-quality research related approaches that relate the quality of software architecture to system requirements, system architecture and enterprise-architecture, or software testing. Modern software has become complex and adaptable due to the emergence of globalization and new software technologies, devices and networks. These changes challenge both traditional software quality assurance techniques and software engineers to ensure software quality when building today (and tomorrow's) adaptive, context-sensitive, and highly diverse applications. This edited volume presents state of the art techniques, methodologies, tools, best practices and guidelines for software quality assurance and offers guidance for future software engineering research and practice. Each contributed chapter considers the practical application of the topic through case studies, experiments, empirical validation, or systematic comparisons with other approaches already in practice. Topics of interest include, but are not limited, to: quality attributes of system/software architectures; aligning enterprise, system, and software architecture from the point of view of total quality; design decisions and their influence on the quality of system/software architecture; methods and processes for evaluating architecture quality; quality assessment of legacy systems and third party applications; lessons learned and empirical validation of theories and frameworks on architectural quality; empirical validation and testing for assessing architecture quality

Quality Concerns in Large Scale and Complex Software-intensive Systems

Software quality management (SQM) is the collection of all processes that ensure that software products, services, and life cycle process implementations meet organizational software quality objectives and achieve stakeholder satisfaction. SQM comprises three basic subcategories: software quality planning, software quality assurance (SQA), and software quality control and software process improvement. This chapter provides a general overview of the SQA domain and discuss the related concept. A conceptual model for software quality framework is provided together with the current approaches for SQA. The chapter concludes with some of the identified challenges and future challenges regarding SQA

Anisotropy of magneto-optical spectra in ultrathin Fe/Au/Fe bilayers

Molecular beam epitaxy grown Au(5 nm)/Fe(1.1 nm)/Au(t)/Fe(1.1 nm)/Au(100 nm)/Fe(1 nm)/MgO(001) structures with t between 1 and 2.5 nm were the subject of optical and magneto-optical (MO) ellipsometry studies at photon energies between 1.5 and 5.4 eV. Both the optical ellipsometry and MO polar Kerr rotation spectra can be explained with a multilayer model based on the bulk optical and MO data for Fe and Au. However, the longitudinal MO Kerr effect spectra depart from the model prediction showing an additional well-resolved structure between 3 and 4 eV. This demonstrates a stronger effect of interfaces on the electronic properties at in-plane magnetization in ultrathin magnetic films. On a macroscopic level the effect can be accounted for by a reduced symmetry of the linear MO tensor

Magneto-optical Faraday and Kerr effect of orthoferrite thin films at high temperatures

Orthoferrites present, as bulk materials, reorientation transitions of their magnetic moment alignment at temperatures depending on the rare-earth (RE) ion. In particular, orthoferrites (REFeO3) with RE = Sm, Dy, present this transition at $T_{\rm SRT} = 443$ K and 36 K, respectively. The spectra of the complex Kerr and Faraday angle have been measured on orthoferrite thin films (RE = Sm, Dy, Y), which were prepared by pulsed laser deposition on amorphous quartz substrates. The obtained spectra exhibit contributions of both surfaces and interfaces. Propagation effects of the polarized light in the magneto-optical medium which is interpreted in terms of a simplified theoretical formalism, is also observed. For selected photon energies, temperature dependent Faraday rotation measurements, $\Theta_{\rm F}$, on orthoferrite thin films (RE = Sm, Dy, Y) have been performed. A quite different thermal variation compared to the bulk magnetization has been observed. Curie temperatures are found to be close to the bulk values or slightly larger by 10 K to 20 K as in the case of DyFeO3 and YFeO3. For RE = Sm and Dy, $\Theta_{\rm F}$ increases with increasing temperature contrary to the saturation magnetization, passes through a maximum at about 460 K and vanishes with a TC of $647 \pm 18$ K, 695 K for RE = Sm and Dy respectively

Magneto-optic spectroscopy of La 2/3 Sr 1/3 MnO 3 films on SrTiO 3 (1 0 0) and (1 1 0) substrates

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