Place, Space, and Motion

(a) Topics and Goals. The Junior Research Group »Place, Space and Motion« investigates the role of spatial concepts in physical theories in the millennium from Plato (4th century BCE) through Philoponus and Simplicius (6th century CE). In particular, we examine the explicit theoretical views of ancient physicists and philosophers concerning space, the spatial features of bodies, and the existence of isomorphisms among space, change, and time. Projects are devoted to issues in Plato’s Timaeus and Aristotle’s Physics, and to the interwoven reception of these texts in Middle Platonism and Late Platonism. We trace the evolving answers given to such central questions as whether space is metaphysically basic or is rather dependent upon bodies or even non-spatial entities (such as souls); the possibility of empty space; the causal role of space in nature; how spatial structures make certain kinds of change possible or necessary. The group aims to produce a series of essays and commentaries examining key texts of Plato and Aristotle and tracing the reception and transformation of their views in Middle- and Late Platonism. (b) Methods. The group engages in close reading and interpretation of ancient texts, with the aim of constructing a history of engagement with the questions indicated above. The main areas of expertise brought to bear on the relevant texts lie in classical philology, history of ideas, history of science, and systematic philosophy. In a weekly research seminar, individual research projects and results are presented in detail and discussed in the light of these varied disciplines and skill sets. (c) State of Discussion. Relevant texts are interpreted both internally and in the light of their relationships with earlier sources and later readings. In this way a narrative is emerging of development and interrelationship among ancient theories of space – a narrative with some shape and coherence, but without the suppression of details and uncertainties. The group is also beginning to pay more attention to epistemological issues, concerning the sources of theoretical knowledge about space, and the evolving standards of argument, justification, and presentation of such knowledge

Über das Glück

Die Schrift Über das Glück: Das Leben des Proklos, verfasst von dem neuplatonischen Philosophen Marinos, ist ein bemerkenswerter Text des späten 5. Jh. n. Chr., der traditionelle biographische, hagiographische und philosophische Themen und Motive mit aktuellen zeitgenössischen Diskursen der Spätantike amalgamiert. Das langjährige Oberhaupt der Neuplatoniker in Athen, der Philosoph Proklos, wird als Leitfigur und paganer Heiliger in einer zunehmend christianisierten Gesellschaft inszeniert. Marinos illustriert anhand seiner Proklos-Figur die Tugenden und Ideale der neuplatonischen Philosophen und schildert dabei programmatisch die (neu-)platonische Ethik und Glückskonzeption. In der Einleitung sowie in den sieben Essays dieses Bandes werden literarische, philosophische, religionsphilosophische, astronomische wie althistorische und sozialgeschichtliche Themen dieses Textes - der hier zum ersten Mal ins Deutsche übersetzt wird - beleuchtet

Coupling DuMuX and DUNE-PDELab to investigate evaporation at the interface between Darcy and Navier-Stokes flow

An implementation of a coupled Navier-Stokes/Darcy model based on different Dune discretization modules is presented. The Darcy model is taken from DuMuX, the Navier-Stokes model is implemented on top of Dune-PDELab, and the coupling is done with help of Dune-MultiDomain together with some project-specific auxiliary code. The Navier-Stokes model features one fluid phase, the Darcy model two fluid phases. Each fluid phase may be composed of two components, in addition, non-isothermal processes are considered. The coupling between free and porous-medium flow uses a sharp interface between both subdomains and conserves mass, momentum, and energy by accounting for the corresponding fluxes across the interface. A cell-centered finite volume method (FVM) is combined with a marker and cell (MAC) scheme. It solves the coupled problem in one monolithic system using a Newton method and a direct linear solver. Numerical results demonstrate the basic functioning and a lab-scale reference application

Flux estimates and oh reaction potential of reactive biogenic volatile organic compounds (BVOCs) from a mixed northern hardwood forest, Atmos

Abstract Diurnal branch-level emission rates of biogenic volatile organic compounds (BVOC) including isoprene, monoterpenes (MT), and sesquiterpenes (SQT) were determined at the University of Michigan Biological Station for the tree species red maple (Acer rubrum), red oak (Quercus rubra), paper birch (Betula papyrifera), white pine (Pinus strobus), and big tooth aspen (Populus grandidentata). These emission rates were combined with detailed biomass distribution and meteorological data and incorporated into the canopy model, model of emissions of gasses and aerosols from nature (MEGAN), for estimating whole-canopy fluxes of isoprene. The modeled half-hour fluxes ðmg C m À2 h À1 Þ and cumulative seasonal fluxes ðmg C m À2 Þ compared favorably with results from direct, canopy-level eddy covariance (EC) isoprene measurements; modeled cumulative seasonal flux deviated less than 30% from the EC results. Significant MT emissions were found from four of the five tree species. MT emissions from three of these were both light-and temperature-dependent and were approximately one order of magnitude greater than light-independent MT emissions. SQT emissions were identified from three of the five tree species. The model was modified to incorporate SQT and both light-dependent and light-independent MT emissions for determining fluxes. Isoprene comprised 495% of the total terpenoid flux with MT and SQT comprising 4% and 0.3%, respectively. The average cumulative fluxes (in mg C m À2 ) from June through September were 2490 for isoprene, 105 for MT, and 7 for SQT. A simple box model analysis was used to estimate the contribution of the isoprene, MT, and SQT emissions to the total OH reactivity. These results confirm that isoprene dominates OH reactions especially during daytime hours. Emissions of reactive MT and SQT increase the BVOC+OH reactivity, but are still lower than estimates of BVOC fluxes at this site necessary for affecting OH reactivity to the significant degree suggested by recent reports.

The Global Atmosphere Watch reactive gases measurement network

Long-term observations of reactive gases in the troposphere are important for understanding trace gas cycles and the oxidation capacity of the atmosphere, assessing impacts of emission changes, verifying numerical model simulations, and quantifying the interactions between short-lived compounds and climate change. The World Meteorological Organization’s (WMO) Global Atmosphere Watch (GAW) program coordinates a global network of surface stations some of which have measured reactive gases for more than 40 years. Gas species included under this umbrella are ozone, carbon monoxide, nitrogen oxides, and volatile organic compounds (VOCs). There are many challenges involved in setting-up and maintaining such a network over many decades and to ensure that data are of high quality, regularly updated and made easily accessible to users. This overview describes the GAW surface station network of reactive gases, its unique quality management framework, and discusses the data that are available from the central archive. Highlights of data use from the published literature are reviewed, and a brief outlook into the future of GAW is given. This manuscript constitutes the overview of a special feature on GAW reactive gases observations with individual papers reporting on research and data analysis of particular substances being covered by the program. - See more at: http://elementascience.org/article/info:doi/10.12952/journal.elementa.000067#sthash.cHvHu0T6.dpu

Reversal of Long-Term Trends in Ethane Identified from the Global Atmosphere Watch Reactive Gases Measurement Network

Reactive gases play an important role in climate and air pollution issues. They control the self-cleansing capability of the troposphere, contribute to air pollution and acid deposition, regulate the lifetimes and provide tracers for deciphering sources and sinks for greenhouse gases. Within GAW, the focus is placed on long-term, high-quality observations of ozone (O3), carbon monoxide (CO), volatile organic compounds (VOC), nitrogen oxides (NOx), and sulfur dioxide (SO2). More than 100 stations worldwide carry out reactive gases measurements with data reported to two World Data Centers. The reactive gases program in GAW cooperates The WMO GAW Reactive Gases Program with regional networks and other global monitoring initiatives in order to attain a complete picture of the tropospheric chemical composition. Observations are being made by in-situ monitoring, measurements from commercial routine air-crafts (e.g. IAGOS), column observations, and from flask sampling networks. Quality control and coordination of measurements between participating stations are a primary emphasis. GAW reactive gases data in rapid delivery mode are used to evaluate operational atmospheric composition forecasts in the EU Copernicus Atmospheric Monitoring Service. Oversight of the program is provided by GAW-WMO coordinated Reactive Gases Scientific Advisory Committee (RG-SAG)

Plato's arguments against conceptualism

Plato’s Parmenides confronts us with a curious, unusual situation: The Socrates that we know only all too well as the white bearded sagacious old man appears as a young student. Indeed, a student defending his innovative theory of the Forms against the severe, though not eristic criticism of the old Eleatic Parmenides. In the course of pleading his case before the old man, he advances the thesis that Forms could only be thoughts that originate nowhere else but in souls or minds1. This is commonly identified with a conceptualist interpretation of the Forms, namely that Forms or universals exist only within the mind and have no external or substantial realit.Peer Reviewe

Hierokles“, „Eutokios“, „Proklos“ (Werke), „Priskianos Lydos“, „Elias und David“

Grundriss der Geschichte der Philosophie, begründet von Friedrich Ueberweg, völlig neu bearbeitete Ausgab