Suchergebnisse

Dense Rydberg gases are out-of-equilibrium systems where strong density-density interactions give rise to effective kinetic constraints. They cause dynamic arrest associated with highly constrained many-body configurations, leading to slow relaxation and glassy behavior. Multicomponent Rydberg gases feature additional long-range interactions such as excitation exchange. These are analogous to particle swaps used to artificially accelerate relaxation in simulations of atomistic models of classical glass formers. In Rydberg gases, however, swaps are real physical processes, which provide dynamical shortcuts to relaxation. They permit the accelerated approach to stationarity in experiment and at the same time have an impact on the nonequilibrium stationary state. In particular, their interplay with radiative decay processes amplifies irreversibility of the dynamics, an effect which we quantify via the entropy production at stationarity. Our work highlights an intriguing analogy between real dynamical processes in Rydberg gases and artificial dynamics underlying advanced Monte Carlo methods. Moreover, it delivers a quantitative characterization of the dramatic effect swaps have on the structure and dynamics of their stationary state. ; We are grateful to M. Marcuzzi and P. Rotondo for in-sightful discussions. The research leading to these results hasreceived funding from the European Research Council underthe European Union's Seventh Framework Programme (GrantNo. FP/2007-2013)/ERC Grant Agreement No. 335266 (ES-CQUMA) and the EPSRC Grants No. EP/M014266/1, No.EP/R04421X/1, and No. EP/R04340X/1. R.G. acknowl-edges the funding received from the European Union's Horizon 2020 research and innovation programme under the MarieSklodowska-Curie Grant Agreement No. 703683. I.L. grate-fully acknowledges funding through the Royal Society Wolf-son Research Merit Award. We are also grateful for accessto the University of Nottingham High Performance Com-puting Facility, and for the computing resources and relatedtechnical support provided by CRESCO/ENEAGRID HighPerformance Computing infrastructure (funded by ENEA,the Italian National Agency for New Technologies, Energyand Sustainable Economic Development and by Italian andEuropean research programmes) and its staff.

Understanding the nonequilibrium behavior of quantum systems is a major goal of contemporary physics. Much research is currently focused on the dynamics of many-body systems in low-dimensional lattices following a quench, i.e., a sudden change of parameters. Already such a simple setting poses substantial theoretical challenges for the investigation of the real-time postquench quantum dynamics. In classical many-body systems, the Kolmogorov-Mehl-Johnson-Avrami model describes the phase transformation kinetics of a system that is quenched across a first-order phase transition. Here, we show that a similar approach can be applied for shedding light on the quench dynamics of an interacting gas of Rydberg atoms, which has become an important experimental platform for the investigation of quantum nonequilibrium effects. We are able to gain an analytical understanding of the time evolution following a sudden quench from an initial state devoid of Rydberg atoms and identify strikingly different behaviors of the excitation growth in the classical and quantum regimes. Our approach allows us to describe quenches near a nonequilibrium phase transition and provides an approximate analytical solution deep in the quantum domain. ; The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme (FP/2007-2013) / ERC Grant Agreement No. 335266 (ESCQUMA), the EPSRC Grant No. EP/M014266/1 and the H2020-FETPROACT-2014 Grant No. 640378 (RYSQ). IL gratefully acknowledges funding through the Royal Society Wolfson Research Merit Award. RG acknowledges the funding received from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No. 703683. We are also grateful for access to the University of Nottingham High Performance Computing Facility.

Increase in the concentration of greenhouse gases (GHGs) in the atmosphere threatens the existence of many ecosystems and their inhabitants. Agricultural activities contribute up to 70 % of total anthropogenic emission of nitrous oxide (N2O), one of the GHGs, which is characterized with the highest global warming potential and contributes to stratospheric ozone depletion. Our study presents the results obtained from the recent field and lab activities carried out in order to obtain better insight into the factors that define the presence of N2O in groundwater. Previous large scale investigations, performed in the Hesbaye chalk aquifer in Eastern Belgium, suggested that the concentration of N2O in the aquifer depends on different, possibly overlapping biochemical processes such as nitrification, denitrification and/or nitrifier-denitrification. This study explored the occurrence of biochemical stratification in the same aquifer and its impact on N2O production and consumption mechanisms. For this purpose low flow sampling technique was applied at different depth intervals to obtain better insight into the extent of oxic and anoxic zones and variability of concentrations of GHGs along the vertical profile. Collected groundwater samples were analyzed for the range of hydrochemical parameters as well as NO3-, N2O, H2O and B isotopes signatures and N2O isotopomers. Afterwards, rates of nitrification and denitrification processes were estimated based on short-term incubations of collected groundwater amended with NO3- and NH4+ compounds labeled with heavy 15N isotope. In addition, in order to characterize the dynamics of ongoing biogeochemical processes, polymerase chain reaction (PCR) tests for detection of the activity-specific enzymes in the aquifer were performed. Such studies help to clarify which conditions are more prone to the accumulation of high concentrations of GHGs in aquifers and better constrain models which estimate local and regional GHGs budgets.AcknowledgmentsThis project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 675120. ; Peer reviewed

9. Natural Resources in the Subsoil and Social Conflicts on the Surface: Perspectives on Peru's Subsurface Political Ecology (Julio C. Postigo, Mariana Montoya, and Kenneth R. Young), p. 223

While corporate sustainability has been defined as an approach that creates long-term value with minimum environmental damage, there is still little understanding of the time horizon over which improved environmental performance leads to improved financial performance. We investigate the relationship between environmental and financial performance under increasing likelihood of environmental regulation. We leverage longitudinal data for 1,095 U.S. corporations from 2004 to 2008, a period of increasing activity for climate change legislation, in order to estimate the effect of greenhouse gas emissions on short- and long-term measures of financial performance. We find that during this period, improving corporate environmental performance causes a decline in an indicator of short-term financial performance, return on assets. Nonetheless, investors see the potential long-term value of improved environmental performance, manifested by an increase in Tobin's q. These results suggest that limited uptake of proactive strategies may in part be attributable to short-term financial performance targets that guide managerial decision making.

© 2015, © 2015 SAGE Publications. While corporate sustainability has been defined as an approach that creates long-term value with minimum environmental damage, there is still little understanding of the time horizon over which improved environmental performance leads to improved financial performance. We investigate the relationship between environmental and financial performance under increasing likelihood of environmental regulation. We leverage longitudinal data for 1,095 U.S. corporations from 2004 to 2008, a period of increasing activity for climate change legislation, in order to estimate the effect of greenhouse gas emissions on short- and long-term measures of financial performance. We find that during this period, improving corporate environmental performance causes a decline in an indicator of short-term financial performance, return on assets. Nonetheless, investors see the potential long-term value of improved environmental performance, manifested by an increase in Tobin's q. These results suggest that limited uptake of proactive strategies may in part be attributable to short-term financial performance targets that guide managerial decision making.

The efficiency of aerodynamic objects with jet engines is the result of many factors, among which nozzle parameters are of great importance in relation to the general engine design and the energy source, that determines the composition and properties of the engine working medium. In this respect, an urgent need was to calculate nozzle gas-dynamic characteristics and geometric parameters at various designing and testing stages of jet engines. Relatively simple calculations involving a large number of assumptions and detailed modeling with regard to the maximum possible number of factors are the basis of the existing modeling approaches. In the present work, the problem was to assess an agreement between such modeling methods of a specific 'high-energy material – working medium – nozzle' system and the experimental ones. The calculations using one-dimensional nozzle theory and the gas dynamics modeling method revealed a 6 % difference in the results of various parameters. At the same time, a closer agreement was noted between the experimental data and the results predicted by the gas dynamics modeling method. Moreover, in comparison to one-dimensional theory, the gas dynamics modeling method of an engine jet nozzle is more labor-intensive and expensive for calculations. Therefore, from the practical viewpoint, it is advisable to give preference to one-dimensional theory to calculate the engine construction and to verify calculations with the use of the modeling methods.

Lithuania is one of Europe's smallest national gas markets until recently reliant, in common with Latvia and Estonia, on imported Russian pipeline gas for all its natural gas requirements. After its accession to the EU in 2004, Lithuania became directly impacted by the developing body of energy market regulation, most notably the Third Package of 2009. While the country could have sought a derogation from the main requirements of the Package, it chose not to and instead embarked upon the difficult task of implementing supply chain unbundling. The subsequent successful execution of a project to build an LNG import facility completed the country's quest for gas supply diversification. This paper by Vija Pakalkaite provides a detailed and comprehensive account and assessment of this process, incorporating material and insights gained from conversations with many of the key players involved. Its content will be of great interest to those in the fields of regulation and geopolitics, but for more general observers of the natural gas arena it provides, as a case study, a means of appreciating the practical implications of the EU regulatory frameworks at play.

After performing the classification of inhomogeneous correlations, a criterion to verify whether contributions to the evolution of a given correlation are negligible or not is established. As a consequence, one can show that a transition from a given correlation back to itself is non negligible in the thermodynamic limit only if all intermediate states are more correlated.