http://idea.library.drexel.edu/handle/1860/779 Search the Channel search http://idea.library.drexel.edu/simple-search http://idea.library.drexel.edu/handle/1860/2753 Title: The 2dF-SDSS LRG and QSO survey: QSO clustering and the L-z degeneracy <br/> <br/>Authors: da Angela, J.; Shanks, T.; Croom, S. M.; Weilbacher, P.; Brunner, R. J.; Couch, W.J.; Miller, L.; Myers, A. D.; Nichol, R. C.; Pimbblet, K. A.; de Propris, R.; Richards, Gordon T.; Ross, N. P.; Schneider, D. P.; Wake, D. A. <br/> <br/>Abstract: We combine the QSO samples from the 2dF QSO Redshift Survey (2QZ) and the 2dF-SDSS LRG and QSO Survey (2SLAQ) in order to investigate the clustering of z 1.4 QSOs and measure the correlation function ( ). The clustering signal in redshift-space and projected along the sky direction is similar to that previously obtained from the 2QZ sample alone. By fitting functional forms to ( , ), the correlation function measured along and across the line of sight, we find, as expected, that , the dynamical infall parameter and 0 m, the cosmological density parameter, are degenerate. However, this degeneracy can be lifted by using linear theory predictions under different cosmological scenarios. Using the combination of the 2QZ and 2SLAQ QSO data, we obtain: QSO(z = 1.4) = 0.60+0.14 −0.11, 0 m = 0.25+0.09 −0.07 which imply a value for the QSO bias, b(z = 1.4) = 1.5 ± 0.2. The combination of the 2QZ with the fainter 2SLAQ QSO sample further reveals that QSO clustering does not depend strongly on luminosity at fixed redshift. This result is inconsistent with the expectation of simple ‘high peaks’ biasing models where more luminous, rare QSOs are assumed to inhabit higher mass haloes. The data are more consistent with models which predict that QSOs of different luminosities reside in haloes of similar mass. By assuming ellipsoidal models for the collapse of density perturbations, we estimate the mass of the dark matter haloes which the QSOs inhabit. We find that halo mass does not evolve strongly with redshift nor depend on QSO luminosity. Assuming a range of relations which relate halo to black hole mass we investigate how black hole mass correlates with luminosity and redshift and ascertain the relation between Eddington efficiency and black hole mass. Our results suggest that QSOs of different luminosities may contain black holes of similar mass. Sat, 02 Feb 2008 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2743 Title: Imaging biomarkers of inflammation in situ with functionalized quantum dots in the dextran sodium sulfate (DSS) model of mouse colitis <br/> <br/>Authors: Karwa, Amol; Papazoglou, Elisabeth; Pourrezaei, Kambiz; Tyagi, Som; Murthy, Sreekant <br/> <br/>Abstract: Objective and Design: Myeloperoxidase (MPO) and proinflammatory cytokines play an important role in the development of inflammation. These markers are generally measured using tedious ELISA procedures. In this study, a novel technique utilizing antibody conjugated quantum dot nanoparticles was developed to detect myeloperoxidase, IL-1 α and TNF-α in vivo in the dextran sodium sulfate (DSS) model of experimental colitis. Materials and Methods: Colitis was induced in animals (n=8 animals/ group) by feeding 4% DSS solution ad libitum for seven to eight days. Quantum Dots exhibiting fluorescence at various wavelengths were conjugated to MPO, IL-1 α and TNF-α polyclonal antibodies and tested in vivo at various stages of colitis. Tissue sections obtained were imaged with confocal microscope. The image intensity obtained from the tissue specimen was correlated with clinical activity measured as Disease Activity Index (DAI). Results: Myeloperoxidase, IL-1α and TNF-α were visualized with quantum dots on various days of disease. The intensity of quantum dots increased with increase in inflammation. The increase in intensity showed an excellent correlation with the DAI based on the clinical parameters. Conclusion: The study demonstrated that multiple biomarkers can be detected simultaneously and their quantitative expression correlated well with clinical disease severity. This novel technology should facilitate design of a novel optical platform for imaging various biomarkers of inflammation, early detection of acute and chronic disease markers and inflammation-mediated cancer markers. This detection may also facilitate determination of therapeutic success. Sun, 29 Oct 2006 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2738 Title: Peeling bifurcations of toroidal chaotic attractors <br/> <br/>Authors: Letellier, Christophe; Gilmore, Robert; Jones, Timothy <br/> <br/>Abstract: Chaotic attractors with toroidal topology van der Pol attractor have counterparts with symmetry that exhibit unfamiliar phenomena. We investigate double covers of toroidal attractors, discuss changes in their morphology under correlated peeling bifurcations, describe their topological structures and the changes undergone as a symmetry axis crosses the original attractor, and indicate how the symbol name of a trajectory in the original lifts to one in the cover. Covering orbits are described using a powerful synthesis of kneading theory with refinements of the circle map. These methods are applied to a simple version of the van der Pol oscillator. Mon, 10 Dec 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2731 Title: Conservative dilations of dissipative multidimensional systems: the commutative and non-commutative settings <br/> <br/>Authors: Ball, Joseph A.; Kaliuzhnyi-Verbovetskyi, Dmitry S. <br/> <br/>Abstract: We establish the existence of conservative dilations for various types of dissipative non-commutative N-dimensional (N-D) systems. As a corollary, a criterion of existence of conservative dilations for corresponding dissipative commutative N-D systems is obtained. We point out the cases where this criterion is always fulfilled, and the cases where it is not always fulfilled. Mon, 29 Oct 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2723 Title: A systems approach for the prediction of wild type MAPK pathway response to targeted drugs <br/> <br/>Authors: Miller, David J.; Ghosh, Avijit <br/> <br/>Abstract: In this paper we simulate the wild type MAPK pathway response to twelve in silico drugs that were previously found to reduce elevated phosphorylated ERK levels (ERK*) in 40 top ranked mutations in a model of the MAPK signal transduction pathway. We nd that a subset of the simulated drugs (notably those targeting GEF and the G G-protein trimer) were able to e ectively inhibit the elevated ERK* levels of the mutated pathways, whilst simultaneously eliciting only minimal inhibition of the wild type pathway ERK* response to EGF stimulation. Fri, 28 Sep 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2700 Title: Two variable orthogonal polynomials on the bicircle and structured matrices <br/> <br/>Authors: Geronimo, Jeffrey S.; Woerdeman, Hugo <br/> <br/>Abstract: We consider bivariate polynomials orthogonal on the bicircle with respect to a positive linear functional. The lexicographical and reverse lexicographical orderings are used to order the monomials. Recurrence formulas are derived between the polynomials of different degrees. These formulas link the orthogonal polynomials constructed using the lexicographical ordering with those constructed using the reverse lexicographical ordering. Relations between the coefficients in the recurrence formulas are derived and used to give necessary and sufficient conditions for the existence of a positive linear functional. These results are then used to construct a class of two variable measures supported on the bicircle that are given by one over the magnitude squared of a stable polynomial. Applications to Fej´er–Riesz factorization are also given. Sun, 29 Oct 2006 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2681 Title: Raman spectra of unfilled and filled carbon nanotubes: theory <br/> <br/>Authors: Gayen, S.; Behera, S. N.; Bose, Shyamalendu M. <br/> <br/>Abstract: The Raman spectra of two G bands and a radial breathing mode RBM of unfilled and filled single-wall semiconducting and metallic carbon nanotubes have been investigated theoretically in the presence of electronphonon and phonon-phonon interactions. Excitation of low frequency optical plasmons in the metallic nanotube is responsible for the peak known as the Breit-Wigner-Fano BWF line shape in the G-band Raman spectra. In a filled nanotube, there is an additional peak due to excitation of the phonon of the filling atom or molecule. Positions, shapes, and relative strengths of these Raman peaks depend on the phonon frequencies of the nanotube and that of the filling atoms, and strengths and forms of the plasmon-phonon and phonon-phonon interactions. For example, filling atoms with phonon frequency close to the RBM frequency of the nanotube may broaden and lower the RBM Raman peak to such an extent that it may become barely visible. Hybridization between the G bands and the filling atom phonon is also strong when these two frequencies are close to each other, and it has important effects on the G band and the BWF line shapes. When the phonon frequency of the filling atom is far from the RBM and G-band frequencies, it gives rise to a separate peak with modest effects on the RBM and G-band spectra. The Raman spectra of semiconducting unfilled and filled nanotubes have similar behaviors as those of metallic nanotubes, except that normally they have Lorentzian line shapes and do not show a BWF line shape. However, if a semiconducting nanotube is filled with donor atoms, it is predicted that the BWF-type line shape may be observed near the RBM, or the G band, or the filling atom Raman peak. Wed, 24 Oct 2007 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2666 Title: EEG neurofeedback: a brief overview and an example of peak alpha frequency training for cognitive enhancement in the elderly <br/> <br/>Authors: Angelakis, Efthymios; Stathopoulou, Stamatina; Frymiare, Jennifer L.; Green, Deborah L.; Lubar, Joel F.; Kounios, John <br/> <br/>Abstract: Neurofeedback (NF) is an electroencephalographic (EEG) biofeedback technique for training individuals to alter their brain activity via operant conditioning. Research has shown that NF helps reduce symptoms of several neurological and psychiatric disorders, with ongoing research currently investigating applications to other disorders and to the enhancement of non-disordered cognition. The present article briefly reviews the fundamentals and current status of NF therapy and research and illustrates the basic approach with an interim report on a pilot study aimed at developing a new NF protocol for improving cognitive function in the elderly. EEG peak alpha frequency (PAF) has been shown to correlate positively with cognitive performance and to correlate negatively with age after childhood. The present pilot study used a double-blind controlled design to investigate whether training older individuals to increase PAF would result in improved cognitive performance. The results suggested that PAF NF improved cognitive processing speed and executive function, but that it had no clear effect on memory. In sum, the results suggest that the PAF NF protocol is a promising technique for improving selected cognitive functions. Tue, 24 Oct 2006 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2646 Title: On "bettering humanity" in science and engineering education <br/> <br/>Authors: Stieb, James A. <br/> <br/>Abstract: Authors such as Krishnamany Selvan argue that “all human endeavors including engineering and science” have a single primary objective: “bettering humanity.” They favor discussing “the history of science and measurement uncertainty.” This paper respectfully disagrees and argues that “human endeavors including engineering and science” should not pursue “bettering humanity” as their primary objective. Instead these efforts should first pursue individual betterment. One cannot better humanity without knowing what that means. However, there is no one unified theory of what is to the betterment of humanity. Simultaneously, there is no one field (neither science, nor engineering, nor philosophy) entitled to rule univocally. Perhaps if theorists tended their own gardens, the common weal would be tended thereby. Sun, 29 Oct 2006 22:58:59 GMT http://idea.library.drexel.edu/handle/1860/2642 Title: Creativity support tools: report from a U.S. National Science Foundation sponsored workshop <br/> <br/>Authors: Shneiderman, Ben; Fischer, Gerhard; Czerwinski, Mary; Resnick, Mitch; Myers, Brad; Candy, Linda; Nakakoji, Kumiyo; Edmonds, Ernest; Eisenberg, Mike; Nunamaker, Jay; Giaccardi, Elisa; Pausch, Randy; Hewett, Thomas T.; Selker, Ted; Jennings, Pamela; Sylvan, Elisabeth; Kules, William; Terry, Michael <br/> <br/>Abstract: Creativity support tools is a research topic with high risk but potentially very high payoff. The goal is to develop improved software and user interfaces that empower users to be not only more productive but also more innovative. Potential users include software and other engineers, diverse scientists, product and graphic designers, architects, educators, students, and many others. Enhanced interfaces could enable more effective searching of intellectual resources, improved collaboration among teams, and more rapid discovery processes. These advanced interfaces should also provide potent support in hypothesis formation, speedier evaluation of alternatives, improved understanding through visualization, and better dissemination of results. For creative endeavors that require composition of novel artifacts (e.g., computer programs, scientific papers, engineering diagrams, symphonies, artwork), enhanced interfaces could facilitate exploration of alternatives, prevent unproductive choices, and enable easy backtracking. This U.S. National Science Foundation sponsored workshop brought together 25 research leaders and graduate students to share experiences, identify opportunities, and formulate research challenges. Two key outcomes emerged: (a) encouragement to evaluate creativity support tools through multidimensional in-depth longitudinal case studies and (b) formulation of 12 principles for design of creativity support tools. As Galileo struggled to view Jupiter through his newly built telescope, he adjusted the lenses and saw four twinkling points of light nearby. After recording their positions carefully, Galileo compared them to his drawings from previous nights. His conclusion that Jupiter had four moons circling it was a profound insight with far reaching implications. Sat, 29 Oct 2005 22:58:59 GMT