Green function techniques in the treatment of quantum transport at the molecular scale

The theoretical investigation of charge (and spin) transport at nanometer length scales requires the use of advanced and powerful techniques able to deal with the dynamical properties of the relevant physical systems, to explicitly include out-of-equilibrium situations typical for electrical/heat transport as well as to take into account interaction effects in a systematic way. Equilibrium Green function techniques and their extension to non-equilibrium situations via the Keldysh formalism build one of the pillars of current state-of-the-art approaches to quantum transport which have been implemented in both model Hamiltonian formulations and first-principle methodologies. We offer a tutorial overview of the applications of Green functions to deal with some fundamental aspects of charge transport at the nanoscale, mainly focusing on applications to model Hamiltonian formulations.Comment: Tutorial review, LaTeX, 129 pages, 41 figures, 300 references, submitted to Springer series "Lecture Notes in Physics

A Mixture of “Cheats” and “Co-Operators” Can Enable Maximal Group Benefit

It is commonly assumed that the world would be best off if everyone co-operates. Experimental and mathematical analysis of “co-operation” in yeast show why this isn't always the case

Metallic, magnetic and molecular nanocontacts

Scanning tunnelling microscopy and break-junction experiments realize metallic and molecular nanocontacts that act as ideal one-dimensional channels between macroscopic electrodes. Emergent nanoscale phenomena typical of these systems encompass structural, mechanical, electronic, transport, and magnetic properties. This Review focuses on the theoretical explanation of some of these properties obtained with the help of first-principles methods. By tracing parallel theoretical and experimental developments from the discovery of nanowire formation and conductance quantization in gold nanowires to recent observations of emergent magnetism and Kondo correlations, we exemplify the main concepts and ingredients needed to bring together ab initio calculations and physical observations. It can be anticipated that diode, sensor, spin-valve and spin-filter functionalities relevant for spintronics and molecular electronics applications will benefit from the physical understanding thus obtained

Art therapy as the science of art therapeutic action. A discussion paper to determine the position of the German-speaking scientific community with regard to art therapy diagnostics and intervention

This article examines the current status of art therapy in its process of scientification in the German speaking scientific community. Based on Kriz's definition of Science (1981), an understanding of art therapy as a science of art therapeutic action and the systematic and in-depth accumulation of experiences with this action is elaborated. With this normative understanding, the current state of the discipline concerning especially the diagnostic and interventional aspect of art therapeutic action is examined. The sources are, among others, current and relevant textbooks of art therapy and art therapy dissertations from the past 12 years, which are based on data from specifically performed art therapy. The examined publications draw a differentiated picture of various aspects of art therapy with emphasis on the description and mostly psychodynamic explanation of therapy processes, works and experiences of the patients. Art therapy itself is mainly found in a prescriptive manner of presentation. Actual descriptions of art therapy are found as incidental findings, but have not been in the centre of investigation. This confirms the findings of already existing systematic literature analyzes on art therapy. Subsequently, possible second order solutions to this persistent problem are discussed.Dieser Artikel untersucht den aktuellen Stand der Kunsttherapie im Prozess der Verwissenschaftlichung in der deutschsprachigen Wissenschaftsgemeinschaft. Ausgehend von der Definition von Wissenschaft von Kriz (1981) wird ein Verständnis von Kunsttherapie als Wissenschaft vom kunsttherapeutischen Handeln und der systematischen und vertiefenden Kumulation der damit verbundenen Erfahrungen herausgearbeitet. Mit diesem normativen Verständnis wird der aktuelle Stand der Disziplin mit dem Fokus auf kunsttherapeutischem Diagnostizieren und Intervenieren untersucht. Herangezogen werden unter anderem aktuelle, maßgebliche Lehrbüchern der Kunsttherapie und diejenigen kunsttherapeutischen Dissertationen der letzten 12 Jahre, die Daten aus konkret durchgeführter Kunsttherapie zugrunde legen. Die untersuchten Publikationen zeichnen ein differenziertes Bild vielfältiger Aspekte des kunsttherapeutischen Geschehens mit Schwerpunkt auf der Beschreibung und meist psychodynamischen Erklärung von Therapieprozessen, Werken und Erlebensweisen der Patienten. Kunsttherapeutisches Handeln selbst findet sich überwiegend in präskriptiver Darstellungsweise. Tatsächliches kunsttherapeutisches Handeln jedoch wird allenfalls als Nebenbefund beschrieben, selbst jedoch nicht untersucht. Damit bestätigt sich der Befund bereits vorliegender systematischer Literaturanalysen zur Kunsttherapie. Anschließend werden mögliche Lösungen für diese anhaltende Problemlage diskutiert

Regional and sectoral varieties of capitalism

This study seeks to go beneath the generalizations that constitute characterizations of national economies in order to examine local and sectoral diversity - in particular, forms of capitalist organization at the level of localized sectors. It reports on the findings of research based on detailed case histories of local economies in four different types of production: modernized craft manufacturing (furniture), mass production (motor vehicles), high-technology production (biopharmaceuticals) and high-tech services (television film-making). In each case a local economy in Germany (usually seen counter-factually as an example of a particularly national system) was compared with one elsewhere in Europe: respectively, southern Sweden, Hungary (compared with eastern Germany) and the UK (for two studies). In the analysis, companies act rationally in response to sector-specific challenges, being partly bound by the existing institutional framework that they encounter, but partly acting to alter it. Two possibilities are distinguished and found in the cases. In the first (structurally conservative) case, arrangements of governance in the national innovation and production system prove to be beneficial for the companies and their aim to stand up to international competition. Insofar as national institutions help companies to deal with competition on their markets, they will probably try to preserve these arrangements. In the second (innovative) case, companies turn away from the national context and develop their own local governance structure. If the national institutional structure is seen as not adequate or 'non-fitting' to deal with sectorally specific terms of competition, then the internal and external coordination of companies - in reaction to challenges posed by the market - is likely to deviate from the national structure. In some instances evidence of 'creative incoherence', where local deviation from the national model provides a creative impulse, is found

Creative Local Development in Cologne and London Film and TV Production

This chapter analyses two case studies on public broadcasting in Germany and the UK. The case studies demonstrate several examples of actors at local and sectoral level taking initiatives to resolve apparent deficiencies for their purposes in the ‘normal’ national array of institutions. A particular surprise of the finding is that in doing so both German and British film and television makers have occasionally, usually by chance, hit on institutions more typical of the other country

Offene Daten, offene Wissenschaft?

Open Science bedeutet einen Paradigmenwechsel: In Datenrepositorien zugängliche Originaldaten anderer Autor/-innen werden wie selbst erhobene Forschungsdaten für die Bearbeitung von eigenen, meist übergreifenden Fragestellungen verwendet. Dabei handelt es sich nicht nur um Daten einer Publikation, sondern um alle brauchbaren Daten einer Studie, die sog. Primärdaten. Durch das Teilen von Daten entsteht ein potenzieller Mehrwert. Daraus ergibt sich die Pflicht, auch die eigenen Forschungsdaten offen zugänglich und für andere nutzbar abzulegen (Open Data).Dies bietet – zumal beim Einsatz von Künstlicher Intelligenz – ein enormes wissenschaftliches Potenzial. Damit sich dieses auch entfalten kann, ist es notwendig, mit den Daten nach den FAIR-Prinzipien umzugehen – das heißt, das eigene Datenkonvolut muss auffindbar, zugänglich, interoperabel und nachnutzbar (englisch: findable, accessible, interoperable, and reusable = FAIR) sein.Die FAIR-Prinzipien liegen sowohl dem EU Data Act als auch dem EU Data Governance Act als den beiden Säulen der europäischen Datenstrategie zugrunde, die in eigenen Gesetzen der Mitgliedsländer einen Niederschlag finden. Forschungsdaten aus den Biowissenschaften haben unterschiedliche Inhalte, etwa Biodiversitäts- und Vorkommensdaten, Taxondaten, umweltbiologische bzw. ökologische Daten, nicht-molekulare Analysedaten sowie molekulare, zumeist Sequenzdaten. Sie werden in unterschiedlichen Datenbanken (Open data resources) verwahrt und stehen allen Forschenden zur Verfügung.Nicht für alle Daten einheitlich zu beantworten ist die Frage nach den Eigentumsrechten an dem deponierten Datenkonvolut. Dabei spielen Gesichtspunkte wie die Originalität der Generierung, der Zweck der Nutzung, der Finanzierung des Forschungsvorhabens sowie der zeitlich definierte Schutz der Daten eine Rolle. Das große Potenzial des freien Datenzugangs ist allerdings nicht ohne Schattenseiten, gerade im Hinblick auf den Missbrauch von an sich nützlichen Biodaten (Dual Use of Concern). Gleichwohl ist „Offene Wissenschaft“ – unterstützt durch eine verbindliche Empfehlung der UNESCO – auf dem besten Weg vom Konzept hin zur gelebten guten wissenschaftlichen Praxis.Open science means a paradigm shift: Deposited in a database, data from other researchers are used like data that have been collected by themselves for new research questions, usually of an overarching nature. This approach does not only apply to data which are selected for a publication but also to all trustworthy data, so-called primary data. Sharing data results in a considerable added value. Thus, researchers are obliged to deposit their own research data as “open data” in public databases. In particular in combination with artificial intelligence, this generates an enormous scientific potential. To enable its unfolding, it is necessary that those data researchers provide must meet the principles: findability, accessibility, interoperability, and reusability (FAIR).These principles underlie the EU Data Act as well as the EU Data Governance Act, both of them representing the pillars of the European Data Strategy, and are reflected in the individual laws of the European member states. Research data in biosciences deal with different contents such as: biodiversity and occurrence data, taxon data, environmental and ecological data, non-molecular analysis data, and molecular – predominantly – sequence data. They are stored in domain-specific databases and are at the scientific community’s free disposal.A difficult matter is the right of data ownership, as this question cannot be answered easily. Several aspects must be considered, e. g. ingenuity/originality of the scientific project and its approach, the purpose of the use of the data, the funding of the project, as well as the protection of the data (e. g. for patents) for a defined period of time. Admittedly, the great potential of free access to data is not without dark sides, especially with regard to the misuse of biodata that are actually useful (Dual Use of Concern). Nevertheless, Open science, supported by the binding UNESCO Recommendation, is well on the way of becoming a lived and good scientific practice