Prognostic simulation and analysis of the impact of climate change on the hydrological dynamics in Thuringia, Germany

International audienceThe impact of predicted climate change on the hydrological dynamics and long term hydrological balance in the federal German state Thuringia was investigated and analysed. For this study the prognostic climate data, provided by the statistical regionalisation approach WETTREG, which is based on results of the global climate model ECHAM5/MPI-OM, was used. This regional climate model provides synthetic climate time series for the existent precipitation and climate station in Germany from 2000 to 2100. This data was processed with the hydrological model J2000g which we used for the regionalisation of the climatological time series data and for the computation of potential and actual evapotranspiration, runoff generation and groundwater recharge. In this study we analysed the two emission scenarios A2 and B1, defined by the Intergovernmental Panel on Climate Change (IPCC) and their impact on the temporal and spatial distribution of temperature, precipitation, evapotranspiration and runoff generation for the time frame 2071?2100 for the entire area of the German state of Thuringia. For this purpose we compared simulation with the scenario data with simulation results based on reference data from 1971?2000. The comparison showed an increase of the mean annual temperature of 1.8 (B1) to 2.2 (A2) °C which is much more distinct during winter. The mean annual precipitation is decreasing only slightly but, the seasonal spatio-temporal rainfall distribution which has major impact on the hydrological water balance is changing significantly. This pattern change results in more precipitation during winter and less in summer. Actual evapotranspiration was computed higher for both scenarios compared to the evapotranspiration of the reference period 1971?2000. As a follow up a decrease in the runoff generation was simulated which was again very variable in space and time. The overall trends worked out in this study showed that it is likely that the extremes of flooding in winter and dry spells in summer might occur more often in Thuringia because of the changing weather conditions due to climate change

Maintenance electroconvulsive therapy for comorbid pharmacotherapy-refractory obsessive-compulsive and schizoaffective disorder

<p>Abstract</p> <p>Objective</p> <p>There is a high comorbidity of schizophrenia and obsessive-compulsory disorder (OCD) associated with more severe symptoms. Standard pharmacotherapy achieve symptom improvement in approximately 60% only.</p> <p>Results</p> <p>We report about a 48-old women treated for depression which developed successively psychotic symptoms (ideas of reference, psychotic worries), negative symptoms (blunted affect, impoverished thinking, difficulties in planning), and obsessive-compulsive symptoms (mainly repeating rituals, avoidance behaviour, collecting and hoarding). She did not respond to combined treatment with neuroleptics and high dose selective serotonin re-uptake inhibitors. She acutely improved during a course of electroconvulsive therapy (ECT) and was maintained on outpatient ECTs fortnightly together with 12 mg sertindol and 45 mg mirtazapine for 42 weeks.</p> <p>Conclusion</p> <p>Maintenance ECT is not an approved therapy in OCD but might be an option in pharmacotherapy refractory cases of comorbid OCD and schizophrenic/schizoaffective disorder.</p

Ground state and finite temperature signatures of quantum phase transitions in the half-filled Hubbard model on a honeycomb lattice

We investigate ground state and finite temperature properties of the half-filled Hubbard model on a honeycomb lattice using quantum monte carlo and series expansion techniques. Unlike the square lattice, for which magnetic order exists at T=0 for any non-zero $U$, the honeycomb lattice is known to have a semi-metal phase at small $U$ and an antiferromagnetic one at large $U$. We investigate the phase transition at T=0 by studying the magnetic structure$and compressibility using quantum monte carlo simulations and by calculating the sublattice magnetization, uniform susceptibility, spin-wave and single hole ordered phase. Our results are consistent with a single continuous transition at$U_c/t$in the range 4-5. Finite temperature signatures of this phase transition are seen in the behavior of the specific heat,$C(T)$, which changes from a two-peaked structure for$U>U_c$to a one-peaked structure for$U < U_c$. Furthermore, the$U$dependence of the low temperature coefficient of$C(T)$exhibits an anomaly at$U \approx U_c$.Comment: 11 pages, 19 figure

Towards a Notion of Distributed Time for Petri Nets

We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models

The Energy Spectrum of Primary Cosmic Ray Electrons in Clusters of Galaxies and Inverse Compton Emission

Models for the evolution of the integrated energy spectrum of primary cosmic ray electrons in clusters of galaxies have been calculated, including the effects of losses due to inverse Compton (IC), synchrotron, and bremsstrahlung emission, and Coulomb losses to the intracluster medium (ICM). The combined time scale for these losses reaches a maximum of ~3e9 yr for electrons with a Lorentz factor ~300. Only clusters in which there has been a substantial injection of relativistic electrons since z <~ 1 will have any significant population of primary cosmic ray electrons at present. In typical models, there is a broad peak in the electron energy distribution extending to gamma~300, and a steep drop in the electron population beyond this. In clusters with current particle injection, there is a power-law tail of higher energy electrons with an abundance determined by the current rate of injection. A significant population of electrons with gamma~300, associated with the peak in the particle loss time, is a generic feature of the models. The IC and synchrotron emission from these models was calculated. In the models, EUV and soft X-ray emission are nearly ubiquitous. This emission is produced by electrons with gamma~300. The spectra are predicted to drop rapidly in going from the EUV to the X-ray band. The IC emission also extends down the UV, optical, and IR bands with a fairly flat spectrum. Hard X-ray (HXR) and diffuse radio emission due to high energy electrons (gamma~10e4) is present only in clusters which have current particle acceleration. Assuming that the electrons are accelerated in ICM shocks, one would only expect diffuse HXR/radio emission in clusters which are currently undergoing a large merger.Comment: Accepted for publication in the Astrophysical Journal, with minor revisons to wording for clarity and one additional reference. 19 pages with 16 embedded Postscript figures in emulateapj.sty. Abbreviated abstract belo

Astronomical Data Management

We present a summary of the major contributions to the Special Session on Data Management held at the IAU General Assembly in Prague in 2006. While recent years have seen enormous improvements in access to astronomical data, and the Virtual Observatory aims to provide astronomers with seamless access to on-line resources, more attention needs to be paid to ensuring the quality and completeness of those resources. For example, data produced by telescopes are not always made available to the astronomical community, and new instruments are sometimes designed and built with insufficient planning for data management, while older but valuable legacy data often remain undigitised. Data and results published in journals do not always appear in the data centres, and astronomers in developing countries sometimes have inadequate access to on-line resources. To address these issues, an 'Astronomers Data Manifesto' has been formulated with the aim of initiating a discussion that will lead to the development of a 'code of best practice' in astronomical data management.Comment: Proceedings of Special Session SPS6 (Astronomical Data Management) at the IAU GA 2006. To appear in Highlights of Astronomy, Volume 14, ed. K.A. van der Huch

Lattice dependence of saturated ferromagnetism in the Hubbard model

We investigate the instability of the saturated ferromagnetic ground state (Nagaoka state) in the Hubbard model on various lattices in dimensions d=2 and d=3. A variational resolvent approach is developed for the Nagaoka instability both for U = infinity and for U < infinity which can easily be evaluated in the thermodynamic limit on all common lattices. Our results significantly improve former variational bounds for a possible Nagaoka regime in the ground state phase diagram of the Hubbard model. We show that a pronounced particle-hole asymmetry in the density of states and a diverging density of states at the lower band edge are the most important features in order to stabilize Nagaoka ferromagnetism, particularly in the low density limit.Comment: Revtex, 18 pages with 18 figures, 7 pages appendices, section on bcc lattice adde

Exact single spin flip for the Hubbard model in d=∞d=\infty

It is shown that the dynamics of a single $\downarrow$-electron interacting with a band of $\uparrow$-electrons can be calculated exactly in the limit of infinite dimension. The corresponding Green function is determined as a continued fraction. It is used to investigate the stability of saturated ferromagnetism and the nature of the ground state for two generic non-bipartite infinite dimensional lattices. Non Fermi liquid behavior is found. For certain dopings the $\downarrow$-electron is bound to the $\uparrow$-holes.Comment: 4 pages, 3 figures included with psfig, Revtex; Phys. Rev. Lett. in press; some amendments made to clarify the calculation of the self-energy, the extrapolation of the continued fraction, and the statements on Fermi-liquid theor

Magnetic Field Evolution in Merging Clusters of Galaxies

We present initial results from the first 3-dimensional numerical magnetohydrodynamical (MHD) simulations of magnetic field evolution in merging clusters of galaxies. Within the framework of idealized initial conditions similar to our previous work, we look at the gasdynamics and the magnetic field evolution during a major merger event in order to examine the suggestion that shocks and turbulence generated during a cluster/subcluster merger can produce magnetic field amplification and relativistic particle acceleration and, as such, may play a role in the formation and evolution of cluster-wide radio halos. The ICM, as represented by the equations of ideal MHD, is evolved self-consistently within a changing gravitational potential defined largely by the collisionless dark matter component represented by an N-body particle distribution. The MHD equations are solved by the Eulerian, finite-difference code, ZEUS. The particles are evolved by a standard particle-mesh (PM) code. We find significant evolution of the magnetic field structure and strength during two distinct epochs of the merger evolution.Comment: 21 pages, 7 figures, Figure 2 is color postscript. Accepted for publication in Ap

Imaging of z~2 QSO host galaxies with the Hubble Space Telescope

We report on deep imaging in 2 filters with the PC2 camera of HST, of five QSOs at redshift ~2, with a range of optical and radio luminosity. The observations included a suite of PSF observations which were used to construct new PSF models, described elsewhere by Dumont et al. The new PSF models were used to remove the QSO nucleus from the images. We find that the host galaxies have resolved flux of order 10% of the QSO nuclei, and are generally luminous and blue, indicating active star-formation. While most have clearly irregular morphologies, the bulk of the flux can be modelled approximately by an r**1/4 law. However, all host galaxies also have an additional approximately exponential luminosity profile beyond a radius about 0.8 arcsec, as also seen in ground-based data with larger telescopes. The QSOs all have a number of nearby faint blue companions which may be young galaxies at the QSO redshift. We discuss implications for evolution of the host galaxies, their spheroidal populations, and central black holes.Comment: 18 pages including 2 tables; to appear in A