Synthetic Mechanochemical Molecular Swimmer

A minimal design for a molecular swimmer is proposed that is a based on a mechanochemical propulsion mechanism. Conformational changes are induced by electrostatic actuation when specific parts of the molecule temporarily acquire net charges through catalyzed chemical reactions involving ionic components. The mechanochemical cycle is designed such that the resulting conformational changes would be sufficient for achieving low Reynolds number propulsion. The system is analyzed within the recently developed framework of stochastic swimmers to take account of the noisy environment at the molecular scale. The swimming velocity of the device is found to depend on the concentration of the fuel molecule according to the Michaelis-Menten rule in enzymatic reactions.Comment: 4 pages, 3 figure

Law and society in a time of transition

This dissertation is used to analyze the reform of the US divorce and custody laws – with special consideration for the legal development in California. A particular focus is on the reasons, which led to the no-fault-reform in the 1960s – an era of socio-political upheaval. First, a portrayal of the concept of society and family in the light of the changes in contemporary history is shown. Here, the basics of the American system of values and the reasons for the changes in society since the 1960s are explained. Following an excursion into legal history and legal tradition, the larger second part discusses the liberalization of divorce law and the resulting withdrawal of governmental intervention from divorce proceedings. Due to the abolition of the fault principle and the introduction of the failure principle, problem solving was shifted from the courts to the spouses. Individuals were now allocated a greater level of personal responsibility. The impulse for this change in the law came from the State of New York, which was to reduce the “divorce tourism“ in federal states with less restrictive laws. As a result, the custody law was also reformed and joint custody was introduced. The development from patriarchal role relations within the family to the introduction of joint custody is the subject of the final part of this work.In dieser Dissertation wird die Reform des Scheidungs- und Sorgerechts in den Vereinigten Staaten von Amerika – unter besonderer Berücksichtigung der Rechtsentwicklung im Bundesstaat Kalifornien – untersucht. Ein besonderes Augenmerk richtet sich hierbei auf die Gründe, die in den 1960er-Jahren – eine Phase gesellschaftspolitischer Umbrüche – zum Wegfall des Schuldprinzips (No-Fault-Reform) führten. Zunächst erfolgt eine Darstellung des Verständnisses von Gesellschaft und Familie im zeitgeschichtlichen Wandel. Hierbei werden die Grundlagen des amerikanischen Wertesystems und die Ursachen der gesellschaftlichen Veränderungen seit den sechziger Jahren des 20. Jahrhunderts verdeutlicht. Im umfangreichen zweiten Teil wird nach einem vorangestellten Exkurs zur Rechtsgeschichte und Rechtstradition die Liberalisierung des Scheidungsrechts und damit der Rückzug staatlicher Intervention bei der Scheidung erörtert. Mit dem Wegfall des Schuldprinzips und der Einführung des Zerrüttungsprinzips verlagerte sich die Problemlösung von den Gerichten hin zu den Ehepaaren. Den beteiligten Individuen wurde damit eine höhere Eigenverantwortung zugewiesen. Der Anstoß für die Gesetzesänderung ging vom Bundesstaat New York aus, der den „Scheidungstourismus“ der Eheleute in Bundesstaaten mit weniger restriktiven Gesetzen einschränken wollte. In der Folge wurde auch das Sorgerecht reformiert und das gemeinsame Sorgerecht eingeführt. Die Entwicklung von einem patriarchalischen Rollenverständnis innerhalb der Familie bis zur Einführung des gemeinsamen Sorgerechts von Mutter und Vater ist Gegenstand des letzten Teils der Arbeit

Local competition and metapopulation processes drive long-term seagrass-epiphyte population dynamics

It is well known that ecological processes such as population regulation and natural enemy interactions potentially occur over a range of spatial scales, and there is a substantial body of literature developing theoretical understanding of the interplay between these processes. However, there are comparatively few studies quantifying the long-term effects of spatial scaling in natural ecosystems. A key challenge is that trophic complexity in real-world biological communities quickly obscures the signal from a focal process. Seagrass meadows provide an excellent opportunity in this respect: in many instances, seagrasses effectively form extensive natural monocultures, in which hypotheses about endogenous dynamics can be formulated and tested. We present amongst the longest unbroken, spatially explict time series of seagrass abundance published to date. Data include annual measures of shoot density, total above-ground abundance, and associated epiphyte cover from five Zostera marina meadows distributed around the Isles of Scilly, UK, from 1996 to 2011. We explore empirical patterns at the local and metapopulation scale using standard time series analysis and develop a simple population dynamic model, testing the hypothesis that both local and metapopulation scale feedback processes are important. We find little evidence of an interaction between scales in seagrass dynamics but that both scales contribute approximately equally to observed local epiphyte abundance. By quantifying the long-term dynamics of seagrass-epiphyte interactions we show how measures of density and extent are both important in establishing baseline information relevant to predicting responses to environmental change and developing management plans. We hope that this study complements existing mechanistic studies of physiology, genetics and productivity in seagrass, whilst highlighting the potential of seagrass as a model ecosystem. More generally, this study provides a rare opportunity to test some of the predictions of ecological theory in a natural ecosystem of global conservation and economic val

Gravity Survey of the Serpent Mound Area, Southern Ohio

Author Institution: Department of Geology, The Ohio State University, Columbus, Ohio 43210Over most of south-central Ohio, the sedimentary Paleozoic rocks exposed at the surface are relatively flat-lying, but in the Serpent Mound area of Highland and Adams Counties they show a circular feature, four miles in diameter, in which the rocks are complexly faulted. This structure has not yet been satisfactorily explained; two of the hypotheses proposed to explain its origin are 1) that it was caused by a "cryptovolcanic" event and 2) that it is an "astrobleme," produced by the impact of a meteoritic body. These two possible mechanisms might be distinguished by the attendant differences in the density variations produced: the cryptovolcanic structure could be associated with large lateral variations in density at the level of the basement rocks, while the meteoritic impact could produce shatter zones and brecciated layers, and small reductions in density in the rock lying closer to the surface. A closely-spaced network of gravity stations extending beyond the limits of the surface expression of the ring structure shows no gravity anomaly pattern that can be related to the surface features. Supporters of the astrobleme hypothesis are more likely to find this evidence useful than are the cryptovolcanists

Cloud Chamber: A Performance with Real Time Two-Way Interaction between Subatomic Particles and Violinist

‘Cloud Chamber’ - a composition by Alexis Kirke, Antonino Chiaramonte, and Anna Troisi - is a live performance in which the invisible quantum world becomes visible as a violinist and subatomic particle tracks interact together. An electronic instrument was developed which can be “played” live by radioactive atomic particles. Electronic circuitry was developed enabling a violin to create a physical force field that directly affects the ions generated by cosmic radiation particles. This enabled the violinist and the ions to influence each other musically in real time. A glass cloud chamber was used onstage to make radioactivity visible in bright white tracks moving within, with the tracks projected onto a large screen

From Bad to Good: Fitness Reversals and the Ascent of Deleterious Mutations

Deleterious mutations are considered a major impediment to adaptation, and there are straightforward expectations for the rate at which they accumulate as a function of population size and mutation rate. In a simulation model of an evolving population of asexually replicating RNA molecules, initially deleterious mutations accumulated at rates nearly equal to that of initially beneficial mutations, without impeding evolutionary progress. As the mutation rate was increased within a moderate range, deleterious mutation accumulation and mean fitness improvement both increased. The fixation rates were higher than predicted by many population-genetic models. This seemingly paradoxical result was resolved in part by the observation that, during the time to fixation, the selection coefficient (s) of initially deleterious mutations reversed to confer a selective advantage. Significantly, more than half of the fixations of initially deleterious mutations involved fitness reversals. These fitness reversals had a substantial effect on the total fitness of the genome and thus contributed to its success in the population. Despite the relative importance of fitness reversals, however, the probabilities of fixation for both initially beneficial and initially deleterious mutations were exceedingly small (on the order of 10(−5) of all mutations)

UR-379 Combatting Data Heterogeneity in Federated Learning

The growing concern in data privacy has led to new paradigms in Machine Learning primarily focused around keep data safe and secure. In our research project, we studied Federated Learning, specifically utilizing knowledge distillation and an autoencoder in an attempt to create a sustainable model that could be used in a field such as Heathcare. We propose a Federated Model using the Flower framework, trained on the MedMNIST2D dataset (Organ(A/C/S)MNIST), using Knowledge Distillation as a method of sharing the global model, and a Variational Autoencoder to deal with the problem of Data Heterogeneity that can arise on a distributed network. Our results on a cumulative model are tentative but hope to prove that the idea can be utilized in networks with varying sizes of edge device, usage, and types.