A Dual Model of Open Source License Growth

Every open source project needs to decide on an open source license. This decision is of high economic relevance: Just which license is the best one to help the project grow and attract a community? The most common question is: Should the project choose a restrictive (reciprocal) license or a more permissive one? As an important step towards answering this question, this paper analyses actual license choice and correlated project growth from ten years of open source projects. It provides closed analytical models and finds that around 2001 a reversal in license choice occurred from restrictive towards permissive licenses.Comment: 14 pages, 6 figure

Resolving the Anglo-German industrial productivity puzzle, 1895-1935 : a response to Professor Ritschl

This paper offers a critical appraisal of the claim of Ritschl (2008) to have found a “possible resolution” to what he calls the “Anglo-German industrial productivity puzzle”. To understand the origins of this term, it is necessary to describe some recent developments in comparisons of industrial labour productivity between Britain and Germany. The Anglo-German industrial productivity puzzle really arose as the result of a new industrial production index produced by Ritschl (2004), which differed very substantially from the widely used index of Hoffmann (1965). Broadberry and Burhop (2007) pointed out that if the Ritschl (2004) index is combined with an index of German employment from Hoffmann (1965) and time series of UK output and employment from Feinstein (1972), it implies an implausibly high German labour productivity lead over Britain in 1907, when projected back from a widely accepted Germany/UK labour productivity benchmark for 1935/36

Heat flow in InAs/InP heterostructure nanowires

The transfer of heat between electrons and phonons plays a key role for thermal management in future nanowire-based devices, but only a few experimental measurements of electron-phonon (e-ph) coupling in nanowires are available. Here, we combine experimental temperature measurements on an InAs/InP heterostructure nanowire system with finite element modeling (FEM) to extract information on heat flow mediated by e-ph coupling. We find that the electron and phonon temperatures in our system are highly coupled even at temperatures as low as 2 K. Additionally, we find evidence that the usual power-law temperature dependence of electron-phonon coupling may not correctly describe the coupling in nanowires and show that this result is consistent with previous research on similar one-dimensional electron systems. We also compare the strength of the observed e-ph coupling to a theoretical analysis of e-ph interaction in InAs nanowires, which predicts a significantly weaker coupling strength than observed experimentally.Comment: 9 pages, 6 figure

Novel Mutants of the Human β1-Adrenergic Receptor Reveal Amino Acids Relevant for Receptor Activation

Activation of G protein-coupled receptors like the beta(1)-adrenergic receptor results in conformational changes that ultimately lead to signal propagation through a G protein to an effector like adenylyl cyclase. In this study we identified amino acids that seem to be critical for activation of the human beta(1)-adrenergic receptor. Activation patterns of mutant receptors were analyzed using two structurally different ligands for beta-adrenergic receptors that both are mixed agonist/antagonists. Broxaterol and terbutaline are agonists at beta(2)- and beta(3)-receptors; however, they act as antagonists at the beta(1)-subtype. We reasoned that this functional selectivity may be reflected by a corresponding sequence pattern in the receptor subtypes. Therefore, we exchanged single amino acids of the beta(1)-adrenergic receptor for residues that were identical in the beta(2)- and beta(3)-subtypes but different in the beta(1)-receptor. Pharmacological characterization of such receptor mutants revealed that binding of a panel of agonists and antagonists including broxaterol and terbutaline was unaltered. However, two of the mutants (I185V and D212N) were activated by broxaterol and terbutaline, which acted as antagonists at the wild-type receptor. Two additional mutants (V120L and K253R) could be activated by terbutaline alone, which is structurally more closely related to endogenous catecholamines like epinephrine than to broxaterol. A model of the human beta(1)-adrenergic receptor showed that the four gain-of-function mutations are outside of the putative ligand-binding domain substantiating the lack of an effect of the mutations on binding characteristics. These results support the notion that Val-120, Ile-185, Asp-212, and Lys-253 are critically involved in conformational changes occurring during receptor activation

Suitability of GRK Antibodies for Individual Detection and Quantification of GRK Isoforms in Western Blots

G protein-coupled receptors (GPCRs) are regulated by GPCR kinases (GRKs) which phosphorylate intracellular domains of the active receptor. This results in the recruitment of arrestins, leading to desensitization and internalization of the GPCR. Aside from acting on GPCRs, GRKs regulate a variety of membrane, cytosolic, and nuclear proteins not only via phosphorylation but also by acting as scaffolding partners. GRKs’ versatility is also reflected by their diverse roles in pathological conditions such as cancer, malaria, Parkinson’s-, cardiovascular-, and metabolic disease. Reliable tools to study GRKs are the key to specify their role in complex cellular signaling networks. Thus, we examined the specificity of eight commercially available antibodies targeting the four ubiquitously expressed GRKs (GRK2, GRK3, GRK5, and GRK6) in Western blot analysis. We identified one antibody that did not recognize its antigen, as well as antibodies that showed unspecific signals or cross-reactivity. Hence, we strongly recommend testing any antibody with exogenously expressed proteins to clearly confirm identity of the obtained Western blot results. Utilizing the most-suitable antibodies, we established the Western blot-based, cost-effective simple tag-guided analysis of relative protein abundance (STARPA). This method allows comparison of protein levels obtained by immunoblotting with different antibodies. Furthermore, we applied STARPA to determine GRK protein levels in nine commonly used cell lines, revealing differential isoform expression

Open-Access-Publikationen mit OS-APS medienneutral und mit automatisiertem Corporate Design erstellen: Anforderungserhebung, Schlussfolgerungen für den Publikationsworkflow und Stand der Umsetzung

Die Universitätsbibliothek Erlangen-Nürnberg, die Universitäts- und Landesbibliothek Sachsen-Anhalt und das Technologieunternehmen SciFlow in Berlin entwickeln gemeinsam die „Open Source Academic Publishing Suite (OS-APS)“, die es Verlagen ermöglichen soll, E-Books einfach und automatisiert ihren Formatvorgaben entsprechend zu erstellen. OS-APS soll einen XML-basierten Single-Source-Publishing-Workflow ermöglichen. Die Software wird Import-, Editier- und Exportfunktionen integrieren, sodass die in Verlagen üblichen Manuskriptformate (z.B. DOCX oder ODT) mit wenigen Mausklicks importiert, analysiert und in das gewünschte Format (z.B. EPUB, PDF, HTML oder XML) im Corporate Design des Verlags umgewandelt werden können. Darüber hinaus werden die Publikationsplattformen Open Journal Systems (OJS) und Open Monograph Press (OMP) sowie die Repositoriumssoftware DSpace an OS-APS angebunden. Um sich im Vorfeld ein Bild von den Anforderungen der Verlage an die Software zu machen, wurde zu Beginn des Projekts eine Anforderungsanalyse in Form einer Online-Umfrage durchgeführt. Dabei wurden Fragen zu Manuskripteingang und -bearbeitung, Publikationsformaten und Zukunftspotenzialen im Verlagswesen gestellt. Die Ergebnisse dieser Umfrage sind in die Entwicklung mit eingeflossen. Im Rahmen des vorliegenden Papers erfolgt zunächst eine kurze Einführung in die Grundlagen des Publizierens mit XML, bevor das BMBF-geförderte Projekt OS-APS inklusive des angedachten Workflows und der einzelnen Softwarekomponenten vorgestellt wird. Im Anschluss daran werden die Ergebnisse der Anforderungsanalyse sowie die daraus entstandenen Schlussfolgerungen für den Workflow ausgeführt. Abschließend wird auf die Einbeziehung der Community und die nächsten anstehenden Entwicklungsschritte eingegangen.The University Library of Erlangen-Nuremberg, the University and State Library of Saxony-Anhalt and the technology company SciFlow in Berlin are jointly developing the “Open Source Academic Publishing Suite (OS-APS)”, which is supposed to enable publishers to create e-books easily and automatically according to their style guidelines. OS-APS will enable an XML-based single-source publishing workflow. The software will integrate import, editing and export functions so that the manuscript formats that commonly occur in publishing houses (e.g., DOCX or ODT) can be imported, analysed and converted into the desired format (e.g., EPUB, PDF, HTML or XML) in the publisher’s corporate design with just a few mouse clicks. In addition, OS-APS will connect to the publication platforms Open Journal Systems (OJS) and Open Monograph Press (OMP) as well as the repository software DSpace. In order to get an idea of the publishers’ requirements for the software in advance, a requirements analysis in the form of an online survey was conducted at the beginning of the project. Questions were asked about manuscript submission and processing, publication formats and future potential in publishing. The results of this survey have been incorporated into the development. This paper begins with a brief introduction to the basics of publishing with XML before presenting the BMBF-funded project OS-APS, including the envisaged workflow and the individual software components. This is followed by the results of the requirements elicitation and the resulting conclusions for the workflow. Finally, the involvement of the community and the next steps regarding the development are discusse

Statistical inference for rough volatility: Central limit theorems

In recent years, there has been substantive empirical evidence that stochastic volatility is rough. In other words, the local behavior of stochastic volatility is much more irregular than semimartingales and resembles that of a fractional Brownian motion with Hurst parameter $H<0.5$. In this paper, we derive a consistent and asymptotically mixed normal estimator of $H$ based on high-frequency price observations. In contrast to previous works, we work in a semiparametric setting and do not assume any a priori relationship between volatility estimators and true volatility. Furthermore, our estimator attains a rate of convergence that is known to be optimal in a minimax sense in parametric rough volatility models

No optical coherence tomography changes in premanifest Huntington's disease mutation carriers far from disease onset.

BACKGROUND Spectral-domain optical coherence tomography (OCT) may detect retinal changes as a biomarker in neurodegenerative diseases like manifest Huntington's disease (HD). We investigate macular retinal layer thicknesses in a premanifest HD (pre-HD) cohort and healthy controls (HC). METHODS Pre-HD mutation carriers underwent standardized ratings and a preset macular OCT scan. Thickness values were determined for each sector of all macular retinal layers, the mean of all sectors and the mean of the inner ring (IR, 3 mm) after segmentation (Heyex segmentation batch). HC were retrospectively included from an existing database. The IR thickness of the ganglion cell layer (GCL), retinal nerve fiber layer (RNFL), GCL + inner plexiform layer (GCIPL), and total retina were included in the exploratory correlation analyses with paraclinical ratings and compared to HC. RESULTS The analyses comprised n = 24 pre-HD participants (n = 10 male, n = 14 female) and n = 38 HC (n = 14 male, n = 24 female). Retinal layer parameters did not correlate with paraclinical ratings. Expected correlations between established HD biomarkers were robust. The IR thicknesses of the GCL, GCIPL, and total retina did not differ between pre-HD and HC. The IR thickness of the RNFL was significantly higher in pre-HD participants (pre-HD: 23.22 μm (standard deviation 2.91), HC: 21.26 μm (1.90), p = .002). DISCUSSION In this cross-sectional cohort of genetically determined pre-HD participants, neurodegenerative features were not detected with retinal layer segmentation. Since our pre-HD collective was more than 16 years before disease onset, OCT may not be sensitive enough to detect early changes