898 research outputs found
Quarkonia Measurements with the Central Detectors of ALICE
A Large Ion Collider Experiment - ALICE will become operational with the
startup of the Large Hadron Collider - LHC at the end of 2007. One focus of the
physics program is the measurement of quarkonia in proton-proton and lead-lead
collisions. Quarkonia states will be measured in two kinematic regions and
channels: di-muonic decays will be measured in the forward region by the muon
arm, the central part of the detector will measure di-electronic decays. The
presented studies show the expected performance of the di-electron measurement
in proton-proton and central lead-lead collisions.Comment: 6 pages, 7 figures, Proceedings of the QM 2006 poster sessio
Sulphonated aromatic pollutants: Limits of microbial degradability and potential of phytoremediation
Many synthetic sulphonated aromatic compounds are used as starting material to produce dyes and pigments, or are released as by-products in the effluents of the textile and dye industry. A large number of these chemicals are poorly biodegradable and cannot be eliminated by classical wastewater treatment plants. To limit the impact of these pollutants on the environment, new processes, based on the use of higher plants (constructed wetlands or hydroponic systems), are under development. Detergents and surfactants are essential for both industrial and domestic applications, the most important family being the alkylbenzene sulphonates. Originally, the alkyl side chains were branched and thus recalcitrant to biodegradation. Therefore, they have been replaced by linear alkylbenzene sulphonates. Although more acceptable, present formulations still have adverse environmental and toxic effects. In this context, phytoremediation appears to be a promising approach to remove these compounds from contaminated soils and water
The use of CORONA images in remote sensing of periglacial geomorphology: an illustration from the NE Siberian coast
CORONA images have been used for the mapping of periglacial features on the Bykovsky Peninsula and adjacent Khorogor Valley in northeast Siberia. Features, mapped and analysed within a geographical information system, include thermokarst depressions, thermo-erosional valleys, thermo-erosional cirques, thermokarst lakes, thermokarst lagoons and pingos. More than 50% of the area is strongly influenced by thermally-induced subsidence. Thermokarst in the area is probably less active today than in the early-middle Holocene
Flexibility of the N-Terminal mVDAC1 Segment Controls the Channel’s Gating Behavior
Since the solution of the molecular structures of members of the voltage dependent anion channels (VDACs), the N-terminal α-helix has been the main focus of attention, since its strategic location, in combination with its putative conformational flexibility, could define or control the channel’s gating characteristics. Through engineering of two double-cysteine mVDAC1 variants we achieved fixing of the N-terminal segment at the bottom and midpoint of the pore. Whilst cross-linking at the midpoint resulted in the channel remaining constitutively open, cross-linking at the base resulted in an “asymmetric” gating behavior, with closure only at one electric field´s orientation depending on the channel’s orientation in the lipid bilayer. Additionally, and while the native channel adopts several well-defined closed states (S1 and S2), the cross-linked variants showed upon closure a clear preference for the S2 state. With native-channel characteristics restored following reduction of the cysteines, it is evident that the conformational flexibility of the N-terminal segment plays indeed a major part in the control of the channel’s gating behavior
Association between workaholism, vital exhaustion, and hair cortisol concentrations among teachers: A longitudinal study testing the moderation effect of neuroticism
Introduction: Workaholism in teachers is characterized by the willingness to work until exhausted and may be associated with various adverse health outcomes as well as high economic costs. The present study examines the association between workaholism, vital exhaustion (VE), and hair cortisol concentration (HCC) as indicators of chronic stress. In addition, this study explores the moderating role of the personality trait neuroticism on the relationship between workaholism and chronic stress indicators, i.e., VE and HCC.
Methods: Forty-two Swiss teachers (28 females; Mage = 39.66, SD = 11.99) completed questionnaires assessing VE (Maastricht Vital Exhaustion Questionnaire), workaholism (Measure of Coping Capacity Questionnaire), and neuroticism (Big-Five Inventory). Together with VE, HCC was assessed twice, with a one year lag.
Results: Both workaholism and neuroticism were positively associated with VE at both time points but not with HCC. Moderation analyses revealed a positive relationship between workaholism and VE in teachers with high neuroticism, while no such association was observed in teachers with low neuroticism. No associations were found between self-reports and HCC.
Discussion: These findings emphasize the importance of considering individual characteristics when investigating VE. Further research is necessary to investigate the applicability of HCC as a biomarker of chronic stress in the context of work
Sediment characteristics of a thermokarst lagoon in the northeastern Siberian Arctic (Ivashkina Lagoon, Bykovsky Peninsula)
Lagoon development in ice-rich permafrost environments such as the Alaskan Beaufort Sea coastline and the Yedoma coastlines of northern Siberia represents a key mechanism of marine inundation of permafrost along the Arctic coastal plains. Here we show lithological, geochronological, and geochemical data from a core drilled in 1999 in Ivashkina Lagoon on the Bykovsky Peninsula in northeastern Siberia. This study extends previous studies of the Ivashkina Lagoon, and provides a first dated geochronological context for sedimentation and lithological characteristics. In addition, we report ground temperature measurements from different borehole sites in and around the lagoon to support our analysis of the thermokarst lagoon environment. Furthermore, a change detection study was carried out using historical aerial photography and modern satellite imagery for the 1982 to 2016 period. Several stages of landscape dynamics were reconstructed, starting with an initial Yedoma Ice Complex that covered the area during the late Pleistocene and which was locally thawed by thermokarst lake development during the Late Glacial with subsequent lacustrine sedimentation. A final stage completed the landscape dynamics during the last few hundreds of years. This stage was characterized by lake drainage and lagoon development, including strong reworking of surface sediments. By extrapolating the organic carbon data from Ivashkina Lagoon to the lagoons of the Bykovsky Peninsula, we estimate that lagoons contain 1.68 ± 0.04 Mt of organic carbon in their upper 6 m
Longitudinal Associations Between Core Self-Evaluation, Vital Exhaustion and Hair Cortisol in Teachers and the Mediating Effects of Resignation Tendency.
Work-related stress appears to be especially high among teachers. However, most research on teacher stress relies exclusively on teachers' self-reports. Little is known about the physiological correlates of affective stress in teachers. This longitudinal study investigates the relationship between core self-evaluation and adverse psychological and physiological stress outcomes in 42 teachers. Self-report questionnaires were used to assess core self-evaluation, vital exhaustion, and resignation tendency. The concentration of cortisol was assessed using hair samples. One year after the initial measurement, vital exhaustion and hair cortisol were assessed again. Path-analytic mediational models showed that core self-evaluation strongly predicted vital exhaustion, and resignation tendency partially mediated this relationship. However, core self-evaluation did not predict hair cortisol concentration. These findings suggest that core self-evaluation plays a crucial role in preventing vital exhaustion among teachers. A positive core self-evaluation seems beneficial for teachers' primary and secondary appraisal and an essential resource for the long-term prevention of self-reported vital exhaustion
Gauge Theory on Fuzzy S^2 x S^2 and Regularization on Noncommutative R^4
We define U(n) gauge theory on fuzzy S^2_N x S^2_N as a multi-matrix model,
which reduces to ordinary Yang-Mills theory on S^2 x S^2 in the commutative
limit N -> infinity. The model can be used as a regularization of gauge theory
on noncommutative R^4_\theta in a particular scaling limit, which is studied in
detail. We also find topologically non-trivial U(1) solutions, which reduce to
the known "fluxon" solutions in the limit of R^4_\theta, reproducing their full
moduli space. Other solutions which can be interpreted as 2-dimensional branes
are also found. The quantization of the model is defined non-perturbatively in
terms of a path integral which is finite. A gauge-fixed BRST-invariant action
is given as well. Fermions in the fundamental representation of the gauge group
are included using a formulation based on SO(6), by defining a fuzzy Dirac
operator which reduces to the standard Dirac operator on S^2 x S^2 in the
commutative limit. The chirality operator and Weyl spinors are also introduced.Comment: 39 pages. V2-4: References added, typos fixe
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