627 Works

Crossover from anomalous to normal diffusion

Daniel Molina-Garcia, Trifce Sandev, Hadiseh Safdari, Gianni Pagnini, Aleksei Chechkin & Ralf Metzler
Abstract The emerging diffusive dynamics in many complex systems show a characteristic crossover behaviour from anomalous to normal diffusion which is otherwise fitted by two independent power-laws. A prominent example for a subdiffusive–diffusive crossover are viscoelastic systems such as lipid bilayer membranes, while superdiffusive–diffusive crossovers occur in systems of actively moving biological cells. We here consider the general dynamics of a stochastic particle driven by so-called tempered fractional Gaussian noise, that is noise with Gaussian...

Rapid evolution of symbiont-­mediated resistance compromises biological control of aphids by parasitoids

Heidi Käch, Hugo Mathé-Hubert, Alice B. Dennis & Christoph Vorburger
There is growing interest in biological control as a sustainable and environmentally friendly way to control pest insects. Aphids are among the most detrimental agricultural pests worldwide, and parasitoid wasps are frequently employed for their control. The use of asexual parasitoids may improve the effectiveness of biological control because only females kill hosts and because asexual populations have a higher growth rate than sexuals. However, asexuals may have a reduced capacity to track evolutionary change...

The assault on international adjudication and the limits of withdrawal

Campbell McLachlan
International adjudication is currently under assault, encouraging a number of States to withdraw, or to consider withdrawing, from treaties providing for international dispute settlement. This Working Paper argues that the act of treaty withdrawal is not merely as the unilateral executive exercise of the individual sovereign prerogative of a State. International law places checks upon the exercise of withdrawal, recognising that it is an act that of its nature affects the interests of other States...

Radiation from accelerated particles in shocks

K.-I. Nishikawa, B. Zhang, E. J. Choi, K. W. Min, J. Niemiec, M. Medvedev, P. Hardee, Y. Mizuno, A. Nordlund, J. Frederiksen, H. Sol, Martin Pohl, D. H. Hartmann & G.J. Fishman
Recent PIC simulations of relativistic electron-positron (electron-ion) jets injected into a stationary medium show that particle acceleration occurs in the shocked regions. Simulations show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields and for particle acceleration. These magnetic fields contribute to the electron’s transverse eflection behind the shock. The “jitter” radiation from deflected electrons in turbulent magnetic fields has properties different from synchrotron radiation calculated in a uniform...

Seasonal forecasting of hydrological drought in the Limpopo Basin

Mathias Seibert, Bruno Merz & Heiko Apel
The Limpopo Basin in southern Africa is prone to droughts which affect the livelihood of millions of people in South Africa, Botswana, Zimbabwe and Mozambique. Seasonal drought early warning is thus vital for the whole region. In this study, the predictability of hydrological droughts during the main runoff period from December to May is assessed using statistical approaches. Three methods (multiple linear models, artificial neural networks, random forest regression trees) are compared in terms of...

Ecological modeling of adaptive evolutionary responses to rapid climate change

Daniel Romero Mujalli
A contemporary challenge in Ecology and Evolutionary Biology is to anticipate the fate of populations of organisms in the context of a changing world. Climate change and landscape changes due to anthropic activities have been of major concern in the contemporary history. Organisms facing these threats are expected to respond by local adaptation (i.e., genetic changes or phenotypic plasticity) or by shifting their distributional range (migration). However, there are limits to their responses. For example,...

Evolution of the selfing syndrome in Arabis alpina (Brassicaceae)

Andrew Tedder, Samuel Carleial, Martyna Gołębiewska, Christian Kappel, Kentaro K. Shimizu & Marc Stift
Introduction The transition from cross-fertilisation (outcrossing) to self-fertilisation (selfing) frequently coincides with changes towards a floral morphology that optimises self-pollination, the selfing syndrome. Population genetic studies have reported the existence of both outcrossing and selfing populations in Arabis alpina (Brassicaceae), which is an emerging model species for studying the molecular basis of perenniality and local adaptation. It is unknown whether its selfing populations have evolved a selfing syndrome. Methods Using macro-photography, microscopy and automated cell...

aspeed

Holger Hoos, Roland Kaminski, Marius Lindauer & Torsten Schaub
Although Boolean Constraint Technology has made tremendous progress over the last decade, the efficacy of state-of-the-art solvers is known to vary considerably across different types of problem instances, and is known to depend strongly on algorithm parameters. This problem was addressed by means of a simple, yet effective approach using handmade, uniform, and unordered schedules of multiple solvers in ppfolio, which showed very impressive performance in the 2011 Satisfiability Testing (SAT) Competition. Inspired by this,...

The Hominin Sites and Paleolakes Drilling Project

Abby Cohen, Christopher Campisano, J. Ramon Arrowsmith, A. Asrat, A. K. Behrensmeyer, A. Deino, C. Feibel, A. Hill, R. Johnson, J. Kingston, Henry Lamb, T. Lowenstein, A. Noren, D. Olago, Richard Bernhart Owen, R. Potts, K. Reed, R. Renaut, F. Schäbitz, J.-J. Tiercelin, Martin H. Trauth, J. Wynn, S. Ivory, K. Brady, R. O’Grady … & B. Zinaye
The role that climate and environmental history may have played in influencing human evolution has been the focus of considerable interest and controversy among paleoanthropologists for decades. Prior attempts to understand the environmental history side of this equation have centered around the study of outcrop sediments and fossils adjacent to where fossil hominins (ancestors or close relatives of modern humans) are found, or from the study of deep sea drill cores. However, outcrop sediments are...

Minimal intervention strategies in logical signaling networks with ASP

Roland Kaminski, Torsten Schaub, Anne Siegel & Santiago Videla
Proposing relevant perturbations to biological signaling networks is central to many problems in biology and medicine because it allows for enabling or disabling certain biological outcomes. In contrast to quantitative methods that permit fine-grained (kinetic) analysis, qualitative approaches allow for addressing large-scale networks. This is accomplished by more abstract representations such as logical networks. We elaborate upon such a qualitative approach aiming at the computation of minimal interventions in logical signaling networks relying on Kleene's...

Magnetic reconnection driven by filament eruption in the 7 June 2011 event

L. van Driel-Gesztelyi, D. Baker, T. Török, Etienne Pariat, L. M. Green, D. R. Williams, J. Carlyle, G. Valori, Pascal Démoulin, S. A. Matthews, Bernhard Kliem & J.-M. Malherbe
During an unusually massive filament eruption on 7 June 2011, SDO/AIA imaged for the first time significant EUV emission around a magnetic reconnection region in the solar corona. The reconnection occurred between magnetic fields of the laterally expanding CME and a neighbouring active region. A pre-existing quasi-separatrix layer was activated in the process. This scenario is supported by data-constrained numerical simulations of the eruption. Observations show that dense cool filament plasma was re-directed and heated...

Explorative Analyse der Preise von Einfamilienhäusern und Eigentumswohnungen in Deutschland

Albrecht Kauffmann & Andreas Nastansky
Untersucht werden die von BulwienGesa erhobenen und aufbereiteten jahresdurch- schnittlichen Wiederverkaufspreise von Eigentumswohungen und Einfamilienhäusern in 401 kreisfreien Städten und Landkreisen für die Jahre 2004–2017. Dabei zeigt sich eine Zunahme der regionalen Streuung im Zeitverlauf vor allem in der auf die Finanzkrise 2007–2009 folgenden Zeit. Im Durchschnitt der Regionen (Landkreise und kreisfreie Städte) steigen die Preise; sie entwickeln sich aber regional stark unterschied- lich (in manchen Regionen stagnieren sie oder sind gefallen). Dies führt auch...

Topologische Datenanalyse

Andreas Nastansky
Bei der Analyse von höherdimensionalen Daten kann deren Gestalt wichtige Informationen über den Datensatz liefern. Bei einer gegebenen Punktwolke, die aus einem unbekannten topologischen Raum ausgewählt wurde, versucht die Topologische Datenanalyse (TDA) den ursprünglichen Raum zu rekonstruieren. Dieser Beitrag soll eine Einführung in die Topologische Datenanalyse geben und konzentriert sich dabei auf zwei wichtige Aspekte: die Persistente Homologie und den Mapper. Dabei werden zuerst die notwendigen theoretischen Grundlagen vorgestellt und anschließend wird die Methodik bei...

Estimating along-track plasma drift speed from electron density measurements by the three Swarm satellites

J. Park, H. Lühr, Claudia Stolle, G. Malhotra, J. B. H. Baker, S. Buchert & R. Gill
Plasma convection in the high-latitude ionosphere provides important information about magnetosphere-ionosphere-thermosphere coupling. In this study we estimate the along-track component of plasma convection within and around the polar cap, using electron density profiles measured by the three Swarm satellites. The velocity values estimated from the two different satellite pairs agree with each other. In both hemispheres the estimated velocity is generally anti-sunward, especially for higher speeds. The obtained velocity is in qualitative agreement with Super...

Inter-comparison of statistical downscaling methods for projection of extreme precipitation in Europe

M. A. Sunyer, Y. Hundecha, D. Lawrence, H. Madsen, Patrick Willems, M. Martinkova, Klaus Vormoor, Gerd Bürger, Martin Hanel, J. Kriaučiūnienė, A. Loukas, M. Osuch & I. Yücel
Information on extreme precipitation for future climate is needed to assess the changes in the frequency and intensity of flooding. The primary source of information in climate change impact studies is climate model projections. However, due to the coarse resolution and biases of these models, they cannot be directly used in hydrological models. Hence, statistical downscaling is necessary to address climate change impacts at the catchment scale. This study compares eight statistical downscaling methods (SDMs)...

Digitization of Spörer’s sunspot drawings

Andrea Diercke, Rainer Arlt & Carsten Denker
Much of our knowledge about the solar dynamo is based on sunspot observations. It is thus desirable to extend the set of positional and morphological data of sunspots into the past. Gustav Spörer observed in Germany from Anklam (1861–1873) and Potsdam (1874–1894). He left detailed prints of sunspot groups, which we digitized and processed to mitigate artifacts left in the print by the passage of time. After careful geometrical correction, the sunspot data are now...

Water and sediment fluxes in Mediterranean mountainous regions

Till Francke, Saskia Foerster, Arlena Brosinsky, Erik Sommerer, Jose Andres Lopez-Tarazon, Andreas Güntner, Ramon J. Batalla & Axel Bronstert
A comprehensive hydro-sedimentological dataset for the Isábena catchment, northeastern (NE) Spain, for the period 2010–2018 is presented to analyse water and sediment fluxes in a Mediterranean mesoscale catchment. The dataset includes rainfall data from 12 rain gauges distributed within the study area complemented by meteorological data of 12 official meteo-stations. It comprises discharge data derived from water stage measurements as well as suspended sediment concentrations (SSCs) at six gauging stations of the River Isábena and...

Integrationsbedarfe und Einstellungsmuster von Geflüchteten im Land Brandenburg

Olaf Glöckner & Wahied Wahdat-Hagh
Rund 40.000 Geflüchtete hat das Land Brandenburg im Zeitraum von 2015 bis 2017 aufgenommen. Viele von ihnen sind aus dem Mittleren Osten und Afrika, teilweise auch aus Russland (Tschetschenien) gekommen. Gefördert vom Bündnis für Brandenburg, haben Forscher des Moses Mendelssohn Zentrums (Universität Potsdam) zahlreiche Gruppeninterviews mit Menschen aus Syrien, Afghanistan, Eritrea und Tschetschenien geführt und einheimische Integrationsexperten befragt. Welche Integrationserfolge, Defizite und kulturellen Differenzen erleben Frauen, Männer, Jugendliche und Kinder aus den genannten Herkunftsländern? Was...

Investigating inferences in sequences of action

Uwe-A. Küttner
This paper offers an exploratory Interactional Linguistic account of the role that inferences play in episodes of ordinary conversational interaction. To this end, it systematically reconsiders the conversational practice of using the lexico-syntactic format oh that's right to implicitly claim "just-now" recollection of something previously known, but momentarily confused or forgotten. The analyses reveal that this practice typically occurs as part of a larger sequential pattern that the participants orient to and which serves as...

Does subsidized care for toddlers increase maternal labor supply?

Kai-Uwe Müller & Katharina Wrohlich
Expanding public or publicly subsidized childcare has been a top social policy priority in many industrialized countries. It is supposed to increase fertility, promote children’s development and enhance mothers’ labor market attachment. In this paper, we analyze the causal effect of one of the largest expansions of subsidized childcare for children up to three years among industrialized countries on the employment of mothers in Germany. Identification is based on spatial and temporal variation in the...

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