140 research outputs found
The 3rd Flow Component as a QGP Signal
Earlier fluid dynamical calculations with QGP show a softening of the
directed flow while with hadronic matter this effect is absent. On the other
hand, we indicated that a third flow component shows up in the reaction plane
as an enhanced emission, which is orthogonal to the directed flow. This is not
shadowed by the deflected projectile and target, and shows up at measurable
rapidities, . To study the formation of this effect initial stages
of relativistic heavy ion collisions are studied. An effective string rope
model is presented for heavy ion collisions at RHIC energies. Our model takes
into account baryon recoil for both target and projectile, arising from the
acceleration of partons in an effective field. The typical field strength
(string tension) for RHIC energies is about 5-12 GeV/fm, what allows us to talk
about "string ropes". The results show that QGP forms a tilted disk, such that
the direction of the largest pressure gradient stays in the reaction plane, but
deviates from both the beam and the usual transverse flow directions. The
produced initial state can be used as an initial condition for further
hydrodynamical calculations. Such initial conditions lead to the creation of
third flow component. Recent measurements are promising that this effect
can be used as a diagnostic tool of the QGP
Modified Boltzmann Transport Equation and Freeze Out
We study Freeze Out process in high energy heavy ion reaction. The
description of the process is based on the Boltzmann Transport Equation (BTE).
We point out the basic limitations of the BTE approach and introduce Modified
BTE. The Freeze Out dynamics is presented in the 4-dimensional space-time in a
layer of finite thickness, and we employ Modified BTE for the realistic Freeze
Out description.Comment: 9 pages, 2 figure
Quark structure of hadrons and high energy collisions
There exists a large field for phenomenological models in which the knowledge
of the structure of hadrons in terms of QCD constituents obtained from deep
inelastic scatterings is related to their behaviour in soft processes. One of
the simplest and oldest models is the additive quark model, with the rules of
quark statistics following from it. Originally, the relations of quark
combinatorics for hadron yields were based on the qualitative description of a
multiparticle production process as a process of the production of
non-correlated quarks and antiquarks followed by their subsequent fusion into
hadrons [20],[21]. As a large amount of new precision measurements appear, and,
on the other hand, our understanding of QCD becomes deeper, a new level of
understanding of quark-gluon physics in the region of soft interactions forces
us to review the relations of quark combinatorics. To do so, an especially good
possibility is provided by the experimental data for hadronic Z^0 decays which
allow us to check the relations of quark combinatorics for a new type of
processes: quark jets in the decays Z^0 -> q\bar{q} -> hadrons [32].Comment: 55 pages, 23 figure
Synaptic and cellular changes induced by the schizophrenia susceptibility gene G72 are rescued by N-acetylcysteine treatment
Genetic studies have linked the primate-specific gene locus G72 to the development of schizophrenia and bipolar disorder. Transgenic mice carrying the entire gene locus express G72 mRNA in dentate gyrus (DG) and entorhinal cortex, causing altered electrophysiological properties of their connections. These transgenic mice exhibit behavioral alterations related to psychiatric diseases, including cognitive deficits that can be reversed by treatment with N-acetylcysteine, which was also found to be effective in human patients. Here, we show that G72 transgenic mice have larger excitatory synapses with an increased amount of N-methyl-d-aspartate (NMDA) receptors in the molecular layer of DG, compared with wild-type littermates. Furthermore, transgenic animals have lower number of dentate granule cells with a parallel, but an even stronger decrease in the number of excitatory synapses in the molecular layer. Importantly, we also show that treatment with N-acetylcysteine can effectively normalize all these changes in transgenic animals, resulting in a state similar to wild-type mice. Our results show that G72 transcripts induce robust alterations in the glutamatergic system at the synaptic level that can be rescued with N-acetylcysteine treatment
Modelling street level PM10 concentrations across Europe: source apportionment and possible futures
Despite increasing emission controls, particulate matter (PM) has remained a critical issue for European air quality in recent years. The various sources of PM, both from primary particulate emissions as well as secondary formation from precursor gases, make this a complex problem to tackle. In order to allow for credible predictions of future concentrations under policy assumptions, a modelling approach is needed that considers all chemical processes and spatial dimensions involved, from long-range transport of pollution to local emissions in street canyons. Here we describe a modelling scheme which has been implemented in the GAINS integrated assessment model to assess compliance with PM10 (PM with aerodynamic diameter <10 um) limit values at individual air quality monitoring stations reporting to the AirBase database. The modelling approach relies on a combination of bottom up modelling of emissions, simplified atmospheric chemistry and dispersion calculations, and a traffic increment calculation wherever applicable. At each monitoring station fulfilling a few data coverage criteria, measured concentrations in the base year 2009 are explained to the extent possible and then modelled for the past and future. More than 1850 monitoring stations are covered, including more than 300 traffic stations and 80% of the stations which exceeded the EU air quality limit values in 2009. As a validation, we compare modelled trends in the period 2000-2008 to observations, which are well reproduced. The modelling scheme is applied here to quantify explicitly source contributions to ambient concentrations at several critical monitoring stations, displaying the differences in spatial origin and chemical composition of urban roadside PM10 across Europe. Furthermore, we analyse the predicted evolution of PM10 concentrations in the European Union until 2030 under different policy scenarios. Significant improvements in ambient PM10 concentrations are expected assuming successful implementation of already agreed legislation; however, these will not be large enough to ensure attainment of PM10 limit values in hot spot locations such as Southern Poland and major European cities. Remaining issues are largely eliminated in a scenario applying the best available emission control technologies to the maximal technically feasible extent
A Line Through the Sacred Lands of the Altai Mountains: Perspectives on the Altai Pipeline Project
In 2006 preliminary plans were made public showing that Gazprom intended to construct a pipeline through the Altai republic (Russia, south-west Siberia). Unfortunately, there was almost no attention to integrating the conservation of cultural heritage (both archaeological and landscape) into the planning of the pipeline, though the Altai is well-known for its rich cultural heritage. Hitherto, no assessment has been made of the potential impact of the project, nor did Gazprom release detailed information about the exact course of the route. The present article aims to illustrate the potential impact of the pipeline based on a detailed study of a small segment of the route, using remote sensing images and data gathered during fieldwork. This assessment underlines the need for a well-thought-out strategy, which is required if sustainable integration of heritage conservation into the construction plan is to be realized. If such a balance is not found, thousands of archaeological monuments could disappear, which would result in a huge cultural and scientific loss. As a possible solution, an integrative strategy founded on a desk-based study of remote sensing images and a well-directed field survey is suggested
Photo-antagonism of the GABAA receptor
Neurotransmitter receptor trafficking is fundamentally important for synaptic transmission and neural network activity. GABAA receptors and inhibitory synapses are vital components of brain function, yet much of our knowledge regarding receptor mobility and function at inhibitory synapses is derived indirectly from using recombinant receptors, antibody-tagged native receptors and pharmacological treatments. Here we describe the use of a set of research tools that can irreversibly bind to and affect the function of recombinant and neuronal GABAA receptors following ultraviolet photoactivation. These compounds are based on the competitive antagonist gabazine and incorporate a variety of photoactive groups. By using site-directed mutagenesis and ligand-docking studies, they reveal new areas of the GABA binding site at the interface between receptor β and α subunits. These compounds enable the selected inactivation of native GABAA receptor populations providing new insight into the function of inhibitory synapses and extrasynaptic receptors in controlling neuronal excitation
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