The Platform Governance Archive v1: A longitudinal dataset to study the governance of communication and interactions by platforms and the historical evolution of platform policies (Data Paper)

Platform policies contain the spelled out rules about what is allowed and prohibited on a service. As such, they constitute both a normative framework as well as a means of public communication by platforms. Studying the evolution of the increasingly complex web of policies that platforms have developed can hence allow us to trace the emergence of a specific normative order, i.e. the ways in which platforms are governing user activities and public speech and communication dynamics, as well as identify how they have reacted to public controversies, political debates and legal regulation. A major difficulty for studies on the historical evolution of platform policies, however, is the availability of past policies which is often needed for a thorough analysis, as the policies change quite frequently and even their names and locations often differ from the current version. Although platforms have become increasingly transparent about how and when they are changing their rules and have begun to offer public archives of the different historical versions of their policies, these archives often do not contain all of the past versions of a policy and relying on them entails trusting the platforms to provide complete information. Thus it remains hard to systematically study how the rules and norms of platforms have changed over time. Our Platform Governance Archive (PGA) aims to address this need by providing a comprehensive and uniformly collected dataset of all of the historical versions of platform policies which does not rely on the platforms’ own public records. While we are working on extending the scope of the archive to include more platforms and policies, the current dataset described in this paper contains all of the historical versions of three types of policy documents (Terms of Service, Community Guidelines, Privacy Policies) by four major platforms (Facebook, YouTube, Twitter and Instagram) in the time period from the inception of each policy until the end of 2021. Our paper gives a comprehensive overview of the conceptual layout of the Platform Governance Archive and details the automated and manual processes of data collection and data cleaning, as well as our practical and theoretical challenges. Starting with how we define a relevant change to a platform policy, we lay out how we used the Internet Archive’s Wayback Machine to identify past versions of platform policies, collect them, and then automatically and manually check for changes. Specifically, we explain how we mapped the URLs of the selected policies and they have changed over time, putting together a puzzle of how they were renamed and relocated. We then detail the automated scraping process of these URLs from the Wayback Machine as well as the automated diff-checking which we employed. The last step of the data cleaning consisted in a manual revision of the automatically identified versions based on our definition of a relevant change, which was necessary because a significant amount of data noise remained. The paper furthermore describes how the platforms' ways of displaying their policies have changed over time by increasingly turning them into interactive pages and multi-page documents, as well as how we addressed the data collection challenges that arose from this. The paper furthermore provides an overview of the resulting v1 corpus the Platform Governance Archive which is a dataset consisting of 354 policy documents with a total of 6,036 pages. By detailing the structure of our data repository on Github, we offer a guide on how to access and work with the data. We furthermore describe the characteristics and details of each platform and policy type to account for the fact that each of them have undergone a specific historical development. Lastly, our paper also presents a structural analysis of some of the general trends and patterns which are visible in the dataset over a time period of up to almost two decades on the document level. Using a quantitative analysis, we analyse how the change frequency and the character count of each platform policy has developed over time. A comparative visualisation of these findings allows us to show how the extent of the policies has grown over time, to identify periods of high growth and frequent changes and to draw comparative conclusions about the four different platforms. The Platform Governance Archive aims to be a resource for researchers, journalists, policy-makers, platform operators, activists, and other stakeholders as well as the general public. By offering both a comprehensive dataset and an accessible interface, we aim to offer and continue to develop this resource to enable research and public debate on the historical evolution of platform policies in order to trace down changes, to identify characteristic periods of isomorphic policies, to measure influencing factors, and to understand how specific debates, events, and legislation have influenced and manifested in platform policies

Auswirkung der Unsymmetrie von Kabeln und passiven Bauteilen auf die EMV der Busschnittstelle am Beispiel von Ethernet für Kfz Anwendungen

Mit "Automotive- Ethernet" wird momentan an der Entwicklung eines weiteren symmetrischen Bussystems für den Einsatz im Kfz gearbeitet. Die Übertragungsrate liegt mit 100 Mbit/s zehnfach über der von FlexRay. Aufgrund der gewählten Übertragungstechnologie und der höheren notwendigen Analogbandbrandbreite sind hier deutlich höhere Anforderungen an die Symmetrie sowie andere Übertragungseigenschaften des Kanals gefordert. Dabei stellt die Einhaltung der Symmetrieanforderungen einen zentralen elektromagnetische Verträglichkeit-relevanten Punkt für das System dar. Zu diesem Zweck wurden speziell angepasste Testspezifikationen für alle Einzelkomponenten des Übertragungskanals entwickelt und stehen für Entwicklungs- und Analysezwecke zur Verfügung. Im Ergebnis der Anwendung dieser Analysemethoden können klare Mindestanforderungen an Symmetrie- und Hochfrequenzeigenschaften aller Komponenten des Übertragungskanals für "Automotive-Ethernet" spezifiziert werden, die einen störungsfreien Einsatz im Kfz und den damit verbunden erhöhten EMV-Anforderungen ermöglichen

Accelerated search kinetics mediated by redox reactions of DNA repair enzymes

A Charge Transport (CT) mechanism has been proposed in several papers (e.g., Yavin, et al. PNAS, v102 3546 (2005)) to explain the localization of Base Excision Repair (BER) enzymes to lesions on DNA. The CT mechanism relies on redox reactions of iron-sulfur cofactors that modify the enzyme's binding affinity. These redox reactions are mediated by the DNA strand and involve the exchange of electrons between BER enzymes along DNA. We propose a mathematical model that incorporates enzyme binding/unbinding, electron transport, and enzyme diffusion along DNA. Analysis of our model within a range of parameter values suggests that the redox reactions can increase desorption of BER enzymes not already bound to their targets, allowing the enzymes to be recycled, thus accelerating the overall search process. This acceleration mechanism is most effective when enzyme copy numbers and enzyme diffusivity along the DNA are small. Under such conditions, we find that CT BER enzymes find their targets more quickly than simple "passive" enzymes that simply attach to the DNA without desorbing.Comment: 17 pages, 8 figure

Untersuchungen zur Störkopplung und Schirmdämpfung von Elektro- und Hybridfahrzeugen

In Elektro- und Hybridfahrzeugen wird das konventionelle 12 V-Bordnetz um ein Hochvoltbordnetz zur Realisierung des elektrischen Traktionssystems erweitert. Durch die Integration wird die Komplexität der Fahrzeugelektronik deutlich gesteigert und eine wesentlich höhere Spannungsebene (bis 1000 V) eingeführt. Aufgrund von funktionell bedingten, schnellen Schaltvorgängen erzeugen die neuen elektronischen Hochvoltkomponenten wie beispielsweise der leistungselektronische Umrichter oder der DC-DC-Wandler Störungen, die bisher im Kraftfahrzeug nicht auftraten. Damit diese Störsignale die fehlerfreie Funktion anderer Elektroniksysteme im Fahrzeug nicht beeinflussen, wird das gesamte Hochvoltsystem u. a. als vollständig geschirmtes System in das Fahrzeug integriert. Andernfalls bietet sich zwischen beiden koexistierenden Bordnetzen ein besonders hohes Verkopplungspotential. Im Mittelpunkt des Beitrags steht die Analyse des Störpotentials von elektrischen Antriebssystemen in elektrisch betriebenen Kraftfahrzeugen. Als Ergebnis zeigt sich, dass eine hochqualitative Schirmung des HV-Systems unabdingbar ist. Diese Schirmung kann dann durch Verlegungsoptionen beeinflusst werden. Daher soll im Beitrag u. a. gezeigt werden, wodurch die Schirmdämpfung real verlegter Leitungen abhängig ist. Es werden Erfahrungen mit verschiedenen Messverfahren vorgestellt, die mit Simulationen zu "worst case" Betrachtungen gegenübergestellt werden. Die EMV-Eigenschaften des Hochvoltsystems werden entscheidend durch die Leitungen und der dazugehörigen Kontaktierungen beeinflusst. Im Beitrag werden daher des Weiteren Ergebnisse und Erfahrungen zur messtechnischen Umsetzung der Untersuchungen, u. a. zur nominellen und realen Bestimmung der Transferimpedanz von Hochvoltleitungen vorgestellt. In den Vergleich werden dabei Einflüsse mechanischer Beanspruchung (Biegeradien), aufbau-bedingter Eigenschaften (Querschnitt, Schirmaufbau) sowie Steckverbindern einbezogen. Auf Basis der Leitungsuntersuchungen und Ergebnissen von Komponenten- sowie Fahrzeugtests steht im Fazit des Beitrages die Zusammenführung des Störpotentials zur Wirkung der Schirmung von Hochvoltleitungen bzw. kompletten Hochvoltsystemen in Elektro- und Hybridfahrzeugen

Atrial secondary tricuspid regurgitation: pathophysiology, definition, diagnosis, and treatment.

Atrial secondary tricuspid regurgitation (A-STR) is a distinct phenotype of secondary tricuspid regurgitation with predominant dilation of the right atrium and normal right and left ventricular function. Atrial secondary tricuspid regurgitation occurs most commonly in elderly women with atrial fibrillation and in heart failure with preserved ejection fraction in sinus rhythm. In A-STR, the main mechanism of leaflet malcoaptation is related to the presence of a significant dilation of the tricuspid annulus secondary to right atrial enlargement. In addition, there is an insufficient adaptive growth of tricuspid valve leaflets that become unable to cover the enlarged annular area. As opposed to the ventricular phenotype, in A-STR, the tricuspid valve leaflet tethering is typically trivial. The A-STR phenotype accounts for 10%-15% of clinically relevant tricuspid regurgitation and has better outcomes compared with the more prevalent ventricular phenotype. Recent data suggest that patients with A-STR may benefit from more aggressive rhythm control and timely valve interventions. However, little is mentioned in current guidelines on how to identify, evaluate, and manage these patients due to the lack of consistent evidence and variable definitions of this entity in recent investigations. This interdisciplinary expert opinion document focusing on A-STR is intended to help physicians understand this complex and rapidly evolving topic by reviewing its distinct pathophysiology, diagnosis, and multi-modality imaging characteristics. It first defines A-STR by proposing specific quantitative criteria for defining the atrial phenotype and for discriminating it from the ventricular phenotype, in order to facilitate standardization and consistency in research

The Value of Success: Acquiring Gains, Avoiding Losses, and Simply Being Successful

A large network of spatially contiguous, yet anatomically distinct regions in medial frontal cortex is involved in reward processing. Although it is clear these regions play a role in critical aspects of reward-related learning and decision-making, the individual contributions of each component remains unclear. We explored dissociations in reward processing throughout several key regions in the reward system and aimed to clarify the nature of previously observed outcome-related activity in a portion of anterior medial orbitofrontal cortex (mOFC). Specifically, we tested whether activity in anterior mOFC was related to processing successful actions, such that this region would respond similarly to rewards with and without tangible benefits, or whether this region instead encoded only quantifiable outcome values (e.g., money). Participants performed a task where they encountered monetary gains and losses (and non-gains and non-losses) during fMRI scanning. Critically, in addition to the outcomes with monetary consequences, the task included trials that provided outcomes without tangible benefits (participants were simply told that they were correct or incorrect). We found that anterior mOFC responded to all successful outcomes regardless of whether they carried tangible benefits (monetary gains and non-losses) or not (controls). These results support the hypothesis that anterior mOFC processes rewards in terms of a common currency and is capable of providing reward-based signals for everything we value, whether it be primary or secondary rewards or simply a successful experience without objectively quantifiable benefits

Understanding the microbial fibre degrading communities & processes in the equine gut

Abstract The equine gastrointestinal tract is a self-sufficient fermentation system, housing a complex microbial consortium that acts synergistically and independently to break down complex lignocellulolytic material that enters the equine gut. Despite being strict herbivores, equids such as horses and zebras lack the diversity of enzymes needed to completely break down plant tissue, instead relying on their resident microbes to carry out fibrolysis to yield vital energy sources such as short chain fatty acids. The bulk of equine digestion occurs in the large intestine, where digesta is fermented for 36–48 h through the synergistic activities of bacteria, fungi, and methanogenic archaea. Anaerobic gut dwelling bacteria and fungi break down complex plant polysaccharides through combined mechanical and enzymatic strategies, and notably possess some of the greatest diversity and repertoire of carbohydrate active enzymes among characterized microbes. In addition to the production of enzymes, some equid-isolated anaerobic fungi and bacteria have been shown to possess cellulosomes, powerful multi-enzyme complexes that further enhance break down. The activities of both anaerobic fungi and bacteria are further facilitated by facultatively aerobic yeasts and methanogenic archaea, who maintain an optimal environment for fibrolytic organisms, ultimately leading to increased fibrolytic microbial counts and heightened enzymatic activity. The unique interactions within the equine gut as well as the novel species and powerful mechanisms employed by these microbes makes the equine gut a valuable ecosystem to study fibrolytic functions within complex communities. This review outlines the primary taxa involved in fibre break down within the equine gut and further illuminates the enzymatic strategies and metabolic pathways used by these microbes. We discuss current methods used in analysing fibrolytic functions in complex microbial communities and propose a shift towards the development of functional assays to deepen our understanding of this unique ecosystem