524 research outputs found
Appendix_A_Crime_Analyst_Perceptions_Instrument - Examining job satisfaction among analysts: the impact of departmental integration, role clarity, and it responsibilities
No full textAppendix_A_Crime_Analyst_Perceptions_Instrument for Examining job satisfaction among analysts: the impact of departmental integration, role clarity, and it responsibilities by Emilee Green and Michael T. Rossler in International Journal of Police Science & Management</p
Cohomology and torsion cycles over the maximal cyclotomic extension
No full textA classical theorem by K. Ribet asserts that an abelian variety defined over the maximal cyclotomic extension K of a number field has only finitely many torsion points. We show that this statement can be viewed as a particular case of a much more general one, namely that the absolute Galois group of K acts with finitely many fixed points on the ?tale cohomology with Q/Z-coefficients of a smooth proper K-variety defined over K. We also present a conjectural generalization of Ribet?s theorem to torsion cycles of higher codimension. We offer supporting evidence for the conjecture in codimension 2, as well as an analogue in positive characteristic
Occurrence of regular, chaotic and hyperchaotic behavior in a family of modified Rossler hyperchaotic systems
No full textIn this paper, we demonstrate that it is possible to control the hyperchaos into the Rossler hyperchaotic system (RHS) by linear feedback of own signals. After introducing of the parameter "b" in the z-equation (b --> b + b(1)x(t) + b(2)y(t) + b(3)z(t) + b(4)w(t)), we study how the global dynamics can be altered in a desired direction (b(n) are considered as free parameters). We make a detailed bifurcation investigation of the modified Rossler hyperchaotic systems by varying the parameters b,. Finally, we calculate the Lyapunov exponents and the information dimension, where the regular, chaotic and hyperchaotic motion of modified RHS exist. (C) 2004 Published by Elsevier Lt
Molecular dynamics simulations of supercooled and amorphous Co100-xZrx: Atomic mobilities and structural properties
No full textMolecular dynamics simulations are reported on Co100-xZrx in the complete range of compositions. The simulations are based on Hausleitner-Hafner potentials. For the glassy states of the alloys, a comparison of simulated pair-correlation functions with experimental data is presented. Diffusivities were evaluated for the liquid and supercooled melt from isothermal simulation runs. Therefrom a strong dependency on alloy composition is found for the critical temperature T-c(x) of the mode-coupling theory. Lines of constant averaged diffusivity in the supercooled melts scale closely with this temperature. The ratio of the component diffusivities shows a more involved variation with temperature and composition. These variations reflect differences in the amorphous structure of the alloys, which are quantified in terms of the chemical short-range-order at the level of tetrahedral clusters. PACS number(s): 61.20.Ja, 61.25.Mv, 64.70.Pf
Stabilization of a fractional-order chain of integrators: a contraction-based approach
No full textIn this paper, stabilization of a chain of fractional-order integrators is attempted. The stability is proved using contraction analysis. A numerical example is presented to illustrate the proposed method
Bi2Sr2Can-1CunO2((n+2))(+delta) thin films on c-axis oriented and vicinal substrates
No full textBi2Sr2Can-1CunO2(n+2)+delta (n = 1,2,3) thin films are prepared on c-axis oriented and vicinal substrates by pulsed-laser deposition. Optimization of substrate temperature, laser fluence and post-annealing conditions produces single-phase, well-oriented and smooth films. The surface morphology, texture, crystallinity and stoichiometry of Bi2Sr2CaCu2O8+delta (Bi-2212) thin films strongly depend on the fabrication parameters. On (001) SrTiO3 substrates, c-axis oriented Bi-2212 films with J(c) (60 K) = 2 x 10(6) A/cm(2) and T-c0 = 82 K are obtained. Vicinal Bi-2212 films grown on miscut substrates reveal anisotropic resistivities independent of film thickness (20-300 am), high J(c) anisotropy and strong in-plane and out-of-plane texture. (C) 2001 Elsevier Science B.V. All rights reserved
Impact on the Onset of Psychosis of a Polygenic Schizophrenia-Related Risk Score and Changes in White Matter Volume
No full textBackground: Reductions in the volume of brain white matter are a common feature in schizophrenia and bipolar disorder while the association between white matter and polygenic schizophrenia-related risk is unclear. To look at the intermediate state between health and the full-blown disorder, we investigated this aspect in groups of patients before and after the onset of psychosis. Methods: On a 3 Tesla scanner, total and regional white matter volumes were investigated by structural magnetic resonance imaging (MRI) in the following groups: 37 at-risk mental state patients (ARMS), including 30 with no transition to psychosis (ARMS-NT) and 7 with a transition to psychosis (ARMS-T) pooled with 25 first episode psychosis (FEP) patients. These T 1 -weighted images were automatically processed with the FreeSurfer software and compared with an odds-ratio-weighted polygenic schizophrenia-related risk score (PSRS) based on the publicly available top white matter single-nucleotide polymorphisms. Results: We found no association, only a trend, between PSRS and white matter volume over all groups (β = 0.24, p = 0.07, 95% confidence interval = [-0.02 - 0.49]). However, a higher PSRS was significantly associated with a higher probability of being assigned to the ARMS-T + FEP group rather than to the ARMS-NT group (β = 0.70, p = 0.02, 95% confidence interval = [0.14 - 1.33]); there was no such association with white matter volume. Additionally, a positive association was found between PSRS and the Brief Psychiatric Rating Scale (BPRS) total score for the pooled ARMS-NT/ARMS-T+FEP sample and for the ARMS-T + FEP group also, but none for the ARMS-NT group only. Conclusion: These findings suggest that at-risk mental state patients with a transition and first-episode psychosis patients have a higher genetic risk for schizophrenia than at-risk mental state patients with no transition to psychosis; this risk was associated with psychopathological symptoms. Further analyses may allow polygenic schizophrenia-related risk scores to be used as biomarkers to predict psychosis
Organization of glomeruli in the main olfactory bulb of Xenopus laevis tadpoles
No full textStructural and functional investigations were carried out to study olfactory glomeruli in the main olfactory bulb (OB) in tadpoles of the clawed frog, Xenopus laevis. Calcium imaging of odor response patterns of OB neurons revealed that the synapses within the glomeruli are functional. Tracing axons of individual olfactory receptor neurons (ORNs), dendrites of mitral/tufted (M/T) cells and processes of periglomerular interneurons indicate that the glomerular architecture is solely determined by terminal branches of ORN axons and tufts of M/T primary dendrites. The small population of periglomerular neurons forms wide-field arborizations that always extend over many glomeruli, enter the glomeruli, but lack any glomerular tufts. Antibodies to synaptophysin indicate a high density of synapses within glomeruli, which was further confirmed at the ultrastructural level and quantified to approximately 0.5 synaptic sites per mum(2). Combining immunocytochemistry and ultrastructural investigations, we show that glomeruli in Xenopus laevis tadpoles lack any cellular borders. Glomeruli are surrounded neither by periglomerular somata nor by glial processes. Taken together, our results demonstrate that olfactory glomeruli in Xenopus laevis tadpoles (1) are fully functional, (2) are spheroidal neuropil aggregations of terminal tufts of ORNs and tufts of primary dendrites of M/T cells, and (3) are not enwrapped by a border formed by juxtaglomerular cells. J. Comp. Neurol. (C) 2003 Wiley-Liss, Inc
Evolution of the particle size distribution of tricalcium silicate during hydration by synchrotron X-ray nano-tomography
No full textThe particle size distribution of tricalcium silicate (C3S) is essential for the modelling of early C3S hydration kinetics. In this study, this parameter is analysed during the main hydration period until the first 20 h by synchrotron near-field ptychographic (NF-PXCT) and holographic (HXCT) computed nano-tomography. Additionally, X-ray diffraction, 29Si NMR, thermal analysis, scanning electron microscopy, and inductively coupled plasma-optical emission spectroscopy were used to investigate the system evolution. The time-dependent pore solution composition is also provided to gain further information. HXCT and NF-PXCT show comparable values regarding the evolution of the C3S particle size distribution during hydration, indicating that C3S particles smaller than 1.3 μm are completely dissolved after 20 h of hydration. The results can be reasonably reproduced by numerical models if for all particle sizes a constant reacted rim thickness for each degree of hydration is assumed. Data on the aqueous phase composition are also provided
Path-integral approach to 't Hooft's derivation of quantum physics from classical physics
No full textWe present a path-integral formulation of 't Hooft's derivation of quantum physics from classical physics. The crucial ingredient of this formulation is Gozzi 's supersymmetric path integral of classical mechanics. We quantize explicitly two simple classical systems: the planar mathematical pendulum and the Rossler dynamical system
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