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Search Results: 1 - 10 of 201878 matches for " P. Lutz "
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A duality method in prediction theory of multivariate stationary sequences
Michael Frank,Lutz P. Klotz
Mathematics , 2001,
Abstract: Let W be an integrable positive Hermitian q x q -matrix valued function on the dual group of a discrete abelian group G such that W^{-1} is integrable. Generalizing results of T. Nakazi and of A. G. Miamee and M. Pourahmadi for q=1 we establish a correspondence between trigonometric approximation problems in L^2(W) and certain approximation problems in L^2(W^{-1}). The result is applied to prediction problems for q-variate stationary processes over G, in particular, to the case where G is the group of integers Z.
Higgs self coupling measurement in e+e- collisions at center-of-mass energy of 500 GeV
C. Castanier,P. Gay,P. Lutz,J. Orloff
Physics , 2001,
Abstract: Feasibility of the measurement of the trilinear self-couplings of the Higgs boson is studied. Such a measurement would experimentally determine the structure of the Higgs potential. Full hadronic and semi-leptonic final states of the double-Higgs strahlung have been investigated.
Liver Enzymes: Interaction Analysis of Smoking with Alcohol Consumption or BMI, Comparing AST and ALT to γ-GT
Lutz P. Breitling, Volker Arndt, Christoph Drath, Hermann Brenner
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0027951
Abstract: Background A detrimental interaction between smoking and alcohol consumption with respect serum γ-glutamyltransferase (γ-GT) has recently been described. The underlying mechanisms remain unknown. The present work aimed to provide further insights by examining similar interactions pertaining to aspartate and alanine transaminase (AST, ALT), routine liver markers less prone to enzyme induction. Methodology/Principal Findings The present cross-sectional analysis was based on records from routine occupational health examinations of 15,281 male employees predominantly of the construction industry, conducted from 1986 to 1992 in Southern Germany. Associations of smoking intensity with log-transformed activities of γ-GT, AST, and ALT were examined in regression models adjusted for potential confounders and including an interaction of smoking with alcohol consumption or body mass index (BMI). Statistically significant interactions of smoking were observed with both alcohol consumption (AST and ALT, each with P<0.0001) and BMI (AST only, P<0.0001). The interactions all were in the same directions as for γ-GT, i.e. synergistic with alcohol and opposite with BMI. Conclusion The patterns of interaction between smoking and alcohol consumption or BMI with respect to AST and ALT resembled those observed for γ-GT. This renders enzyme induction a less probable mechanism for these associations, whereas it might implicate exacerbated hepatocellular vulnerability and injury.
Isolation and analysis of high quality nuclear DNA with reduced organellar DNA for plant genome sequencing and resequencing
Kerry A Lutz, Wenqin Wang, Anna Zdepski, Todd P Michael
BMC Biotechnology , 2011, DOI: 10.1186/1472-6750-11-54
Abstract: We describe optimized protocols for isolation of nuclear DNA from eight different plant species encompassing both monocot and eudicot species. These protocols use nuclei isolation to minimize chloroplast and mitochondrial DNA contamination. We also developed a protocol to determine the number of chloroplast and mitochondrial DNA copies relative to the nuclear DNA using quantitative real time PCR (qPCR). We compared DNA isolated from nuclei to total cellular DNA isolated with the CTAB method. As expected, DNA isolated from nuclei consistently yielded nuclear DNA with fewer chloroplast and mitochondrial DNA copies, as compared to the total cellular DNA prepared with the CTAB method. This protocol will allow for analysis of the quality and quantity of nuclear DNA before starting a plant whole genome sequencing or resequencing experiment.Extracting high quality, high molecular weight nuclear DNA in plants has the potential to be a bottleneck in the era of whole genome sequencing and resequencing. The methods that are described here provide a framework for researchers to extract and quantify nuclear DNA in multiple types of plants.In many plant species, extracting large amounts of high quality, high molecular weight DNA can be a challenge due to high amounts of phenolic compounds, high levels of DNases and the presence of large amounts of organellar DNA (reviewed in [1]). Plant cells have three genomes, nuclear, plastid and mitochondrial. The number of organelles and genome copies per organelle depends on the species, cell type and age of the tissue. In Arabidopsis thaliana, a diploid plant species, each cell has two copies of each nuclear genome (gDNA). As the plant ages the number of genomes per cell can increase; the penultimate stage of rosette leaves has an average of 13 genome copies per cell [2]. The number of mitochondria and plastids can vary in different cell types. In an Arabidopsis root cell there are ~400 mitochondria [3], whereas maize anther cells have a 2
Emprego de um catalisador de cromo (III) contendo o ligante N,N'-di-t-Bu-2,11-diaza [3.3] (2,6)-piridinofano na polimeriza??o de etileno e de propileno
Meneghetti, Simoni M. P.;Lutz, Pierre;Kress, Jacky;
Polímeros , 2003, DOI: 10.1590/S0104-14282003000200009
Abstract: chromium (iii) complex bearing n,n'- di-t-bu-2, 11-diaza[3.3] (2,6)-pyridinophane ligand (t-bu-n4crcl2+ cl) was synthesized and characterized. this complex was tested in ethylene and propylene polymerisation, under several reaction conditions, in the presence of mao (metilaluminoxane) or et3al2cl3 (ethyl aluminium sesquichloride), as cocatalysts. the use of the catalytic system t-bu-n4crcl2+ cl -/et3al2cl3 led to ethylene-propylene copolymers and polyethylene, with good yields. the polymers thus produced display high molar masses and narrow polydispersities.
Emprego de um catalisador de cromo (III) contendo o ligante N,N'-di-t-Bu-2,11-diaza [3.3] (2,6)-piridinofano na polimeriza o de etileno e de propileno
Meneghetti Simoni M. P.,Lutz Pierre,Kress Jacky
Polímeros , 2003,
Abstract: Este trabalho trata da síntese e caracteriza o de um complexo de Cr(III) contendo o ligante N,N'-di-t-Bu-2,11-diaza [3.3] (2,6)-piridinofano (t-Bu-N4CrCl2+ Cl-) e posterior avalia o catalítica na polimeriza o de etileno e propileno, sob várias condi es de rea o, em presen a de MAO (metilaluminoxana) ou Et3Al2Cl3 (sesquicloreto de etilalumínio - EASC), como cocatalisadores. O emprego do sistema catalítico t-Bu-N4CrCl2+ Cl-/Et3Al2Cl3 produziu copolímeros de etileno-propileno e de polietilenos, com bons rendimentos. A caracteriza o desses polímeros, através de várias técnicas analíticas, mostrou que os mesmos s o essencialmente lineares e de alta massa molar.
T.A. Lutz,P.A. Rushing,T. Riediger
The Scientific World Journal , 2001, DOI: 10.1100/tsw.2001.425
Single-Atom Gating of Quantum State Superpositions
Christopher R. Moon,Christopher P. Lutz,Hari C. Manoharan
Physics , 2009, DOI: 10.1038/nphys930
Abstract: The ultimate miniaturization of electronic devices will likely require local and coherent control of single electronic wavefunctions. Wavefunctions exist within both physical real space and an abstract state space with a simple geometric interpretation: this state space--or Hilbert space--is spanned by mutually orthogonal state vectors corresponding to the quantized degrees of freedom of the real-space system. Measurement of superpositions is akin to accessing the direction of a vector in Hilbert space, determining an angle of rotation equivalent to quantum phase. Here we show that an individual atom inside a designed quantum corral can control this angle, producing arbitrary coherent superpositions of spatial quantum states. Using scanning tunnelling microscopy and nanostructures assembled atom-by-atom we demonstrate how single spins and quantum mirages can be harnessed to image the superposition of two electronic states. We also present a straightforward method to determine the atom path enacting phase rotations between any desired state vectors. A single atom thus becomes a real space handle for an abstract Hilbert space, providing a simple technique for coherent quantum state manipulation at the spatial limit of condensed matter.
De-coupling of Exchange and Persistence Times in Atomistic Models of Glass Formers
Lester O. Hedges,Lutz Maibaum,David Chandler,Juan P. Garrahan
Physics , 2007, DOI: 10.1063/1.2803062
Abstract: With molecular dynamics simulations of a fluid mixture of classical particles interacting with pair-wise additive Weeks-Chandler-Andersen potentials, we consider the time series of particle displacements and thereby determine distributions for local persistence times and local exchange times. These basic characterizations of glassy dynamics are studied over a range of super-cooled conditions and shown to have behaviors, most notably de-coupling, similar to those found in kinetically constrained lattice models of structural glasses. Implications are noted.
Skull-stripping for Tumor-bearing Brain Images
Stefan Bauer,Lutz-P. Nolte,Mauricio Reyes
Computer Science , 2012,
Abstract: Skull-stripping separates the skull region of the head from the soft brain tissues. In many cases of brain image analysis, this is an essential preprocessing step in order to improve the final result. This is true for both registration and segmentation tasks. In fact, skull-stripping of magnetic resonance images (MRI) is a well-studied problem with numerous publications in recent years. Many different algorithms have been proposed, a summary and comparison of which can be found in [Fennema-Notestine, 2006]. Despite the abundance of approaches, we discovered that the algorithms which had been suggested so far, perform poorly when dealing with tumor-bearing brain images. This is mostly due to additional difficulties in separating the brain from the skull in this case, especially when the lesion is located very close to the skull border. Additionally, images acquired according to standard clinical protocols, often exhibit anisotropic resolution and only partial coverage, which further complicates the task. Therefore, we developed a method which is dedicated to skull-stripping for clinically acquired tumor-bearing brain images.
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