Modeling with the Crowd: Optimizing the Human-Machine Partnership with Zooniverse

LSST and Euclid must address the daunting challenge of analyzing the unprecedented volumes of imaging and spectroscopic data that these next-generation instruments will generate. A promising approach to overcoming this challenge involves rapid, automatic image processing using appropriately trained Deep Learning (DL) algorithms. However, reliable application of DL requires large, accurately labeled samples of training data. Galaxy Zoo Express (GZX) is a recent experiment that simulated using Bayesian inference to dynamically aggregate binary responses provided by citizen scientists via the Zooniverse crowd-sourcing platform in real time. The GZX approach enables collaboration between human and machine classifiers and provides rapidly generated, reliably labeled datasets, thereby enabling online training of accurate machine classifiers. We present selected results from GZX and show how the Bayesian aggregation engine it uses can be extended to efficiently provide object-localization and bounding-box annotations of two-dimensional data with quantified reliability. DL algorithms that are trained using these annotations will facilitate numerous panchromatic data modeling tasks including morphological classification and substructure detection in direct imaging, as well as decontamination and emission line identification for slitless spectroscopy. Effectively combining the speed of modern computational analyses with the human capacity to extrapolate from few examples will be critical if the potential of forthcoming large-scale surveys is to be realized.Comment: 5 pages, 1 figure. To appear in Proceedings of the International Astronomical Unio

Molekulare Charakterisierung des Amyloidvorläuferproteins des Meerschweinchens

Die Bildung von Amyloidablagerungen ist ein Kennzeichen der Alzheimerschen Erkrankung. Hauptbestandteil dieser senilen Plaques sind sogenannte A beta Peptide, die durch proteolytische Prozessierung aus einem Vorläufermolekül (APP) gebildet werden. Die vorliegende Arbeit beschreibt die Klonierung des Meerschweinchen - APP. Diese cDNA-Sequenz zeigt auf DNA-Ebene eine Homologie zum Human-APP von ca. 90%, auf Proteinebene beträgt die Identität ca. 97 %. Damit wird ein weiterer experimenteller Beweis für die evolutionäre Konservierung des Amyloidvorläuferproteins in Säugetieren erbracht. APP mRNA wird in Meerschweinchen-Geweben ubiquitär exprimiert. Durch alternatives Spleißen wird ein zum Human-APP im wesentlichen ähnliches Isoformenmuster gebildet: Isoformen, welche eine Proteaseinhibitordomäne enthalten, werden dominierend in peripheren Organen exprimiert, dagegen ist im Zentralnervensystem das APP 695 mit über 60 % der Gesamttranskripte die bevorzugt exprimierte Isoform. Die klonierte cDNA des Meerschweinchen-APP wurde in prokaryontischen wie auch eukaryontischen Zellsystemen exprimiert. Dabei wurde die Eignung einer Anzahl von gegen Human-APP gewonnenen Antikörpern zur Detektion des Meerschweinchen-APP und seiner Prozessierungsprodukte gezeigt. Die Expression der neuronal dominierend exprimierten Isoform APP 695 des Meerschweinchen-APP in humanen Neuroblastom-Zellen zeigte keine Unterschiede hinsichtlich der APP-Prozessierung und A beta-Bildung im direkten Vergleich zu Human-APP 695. Die proteolytische Prozessierung des Proteins wurde durch Detektion der typischen Spaltprodukte in vivo (im Liquor) als auch in einem neu etablierten in vitro-Modell primär kultivierter neuronaler Zellen untersucht. Diese Zellkulturen wurden zunächst immunhistochemisch und biochemisch charakterisiert und als "mixed brain"-Typ mit einem hohen neuronalen Anteil beschrieben. Die Prozessierung des endogenen Meerschweinchen-APP in kultivierten Zellen führt dabei zur Bildung und Akkumulation aggregationsfähiger A beta - Peptide. Zur Detektion dieser Peptide wurde ein sensitiver Nachweis durch Western-Blot etabliert. Es wird damit ein Modellsystem für in vitro-Untersuchungen vorgeschlagen, welches ein Studium der Expression und Prozessierung des Amyloidvorläuferproteins unter angenähert physiologischen Bedingungen ermöglicht.A beta peptides, the major component of neuritic plaques found in the brains of patients with Alzheimer\u92s disease, are derived by proteolytic processing from a larger precursor molecule (amyloid precursor protein - APP). A combination of PCR methods was used to clone and sequence APP cDNA from guinea pig (Cavia porcellus). Guinea pig APP exhibits extensive similarities to human APP in terms of primary structure, mRNA expression of differentially spliced isoforms as shown by Northern blot and RT-PCR analysis as well as proteolytic processing to amyloidogenic A beta peptides. In contrast to rat and mouse APP, guinea pig APP - recombinantly expressed in human neuroblastoma-cells - was processed indistinguishable from human APP thus excluding intrinsic sequence-specific factors influencing processing. Further studies were performed using newly established primary cell cultures of guinea pig neurons. Refined methods have been used to detect and characterize major proteolytic processing products of APP in vitro and in vivo. In conclusion, guinea pigs provide a model to study expression and processing of APP that closely resembles the physiological situation in humans and should, therefore, be important in elucidating potential strategies to prevent amyloid formation in Alzheimers Disease

Basis expansions and roots of Ehrhart polynomials

Postprint (published version

Dispersal of Galactic Magnetic Fields into Intracluster Space

Little is known about the origin and basic properties of magnetic fields in clusters of galaxies. High conductivity in magnetized interstellar plasma suggests that galactic magnetic fields are (at least partly) ejected into intracluster (IC) space by the same processes that enrich IC gas with metals. We explore the dispersal of galactic fields by hydrodynamical simulations with our new {\em Enzo-Galcon} code, which is capable of tracking a large number galaxies during cluster assembly, and modeling the processes that disperse their interstellar media. Doing so we are able to describe the evolution of the mean strength of the field and its profile across the cluster. With the known density profile of dispersed gas and an estimated range of coherence scales, we predict the spatial distribution of Faraday rotation measure and find it to be consistent with observational data

Towards a reflexive turn in the governance of global environmental expertise the cases of the IPCC and the IPBES

The role and design of global expert organizations such as the Intergovernmental Panel on Climate Change (IPCC) or the Intergovernmental Platform on Biodiversity and Ecosystem Services (IPBES) needs rethinking. Acknowledging that a one-size-fits-all model does not exist, we suggest a reflexive turn that implies treating the governance of expertise as a matter of political contestation

A cosmopolitan temptation

For some, the transnationalization of political action and communicative space in the European Union heralds an emergent cosmopolitan order. Need that be so? There are supranational institutions in the EU as well as transnational political and cultural spaces and cross-border communicative flows. However, the Union's member states remain key controllers of citizenship rights and purveyors of collective identities. And for many purposes they still maintain strongly bounded national public spheres. Because the EU's overall character as a polity remains unresolved, this has consequences for the organization of communicative spaces. The EU is a field of tensions and contradictions that is inescapably rooted in institutional realities. Wishful thinking about cosmopolitanism can get in the way of clear analysis