bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantum algorithms for number fields
Authors: Haase D. , Maier H. 
Published: August 2006

AbstractThis is a survey of recent results on quantum algorithms for the computation of invariants of number fields, namely the class number and the regulator. Most known classical algorithms for the computation of these values are of subexponential complexity and depend on the truth of a still unproven hypothesis of analytic number theory. We use an important number theoretic concept, Minkowski's Geometry of Numbers, to visualize these invariants, and describe the quantum algorithms developed by Hallgren, Schmidt and Vollmer which compute these invariants using a polynomial number of steps. Computational techniques in number fields, which are necessary to justify the classical part of these quantum algorithms, are the focus of the research of our project group, and are explained in detail.
Factorization of numbers with physical systems
Authors: Merkel W. , Averbukh I.Sh. , Girard B. , Paulus G.G. , Schleich W.P. 
Published: August 2006

AbstractThe periodicity properties of Gauss sums allow us to factor integer numbers. We show that the excitation probability amplitudes of appropriate quantum systems interacting with specific laser fields are determined by Gauss sums. The resulting probabilities are experimentally accessible by measuring the fluorescence from this level. In particular, we discuss a two‐photon transition in a ladder system driven by a chirped laser pulse. In addition, we consider two realizations of laser driven one‐photon transitions. For each quantum system we demonstrate the power of this factorization scheme using numerical examples.
Quantum limit of the Carnot engine
Authors: Tonner F. , Mahler G. 
Published: August 2006

AbstractTo what extent can the design principles of a macroscopic machine be down‐scaled to the nanoscopic level? This question pertains to machine functions as diverse as information processing or energy conversion. Here we will be concerned with the class of Carnot engines. Our minimal model consists of a single spin coupled to an oscillator sandwiched between two thermal baths at different temperatures. Phase sensitive control can be implemented in an autonomous fashion. While this open quantum system still allows for Carnot‐type cycles, decoherence will eventually force the system into a stationary state of heat transport.
Optimization of segmented linear Paul traps and transport of stored particles
Authors: Schulz S. , Poschinger U. , Singer K. , Schmidt‐Kaler F. 
Published: August 2006

AbstractSingle ions held in linear Paul traps are promising candidates for a future quantum computer. Here, we discuss a two‐layer microstructured segmented linear ion trap. The radial and axial potentials are obtained from numeric field simulations and the geometry of the trap is optimized. As the trap electrodes are segmented in the axial direction, the trap allows the transport of ions between different spatial regions. Starting with realistic numerically obtained axial potentials, we optimize the transport of an ion such that the motional degrees of freedom are not excited, even though the transport speed far exceeds the adiabatic regime. In our optimization we achieve a transport within roughly two oscillation periods in the axial trap potential compared to typical adiabatic transports that take of the order 102 oscillations. Furthermore heating due to quantum mechanical effects is estimated and suppression strategies are proposed.
Density functional theory study of tautomerization of 2‐aminothiazole in the gas phase and in solution
Authors: Zeng Yi , Ren Yi 
Published: August 2006

AbstractThe amino/imino tautomeric equilibrium in the isolated, mono‐, di‐, and trihydrate forms and dimer of 2‐aminothiazole, and the effects of hydration or self‐assistance on the transition state structures corresponding to proton transfer from the amino to imino form, have been investigated by the B3LYP method in conjunction with 6‐31+G(d,p) and 6‐311+G(3df,2p) basis sets in the gas phase and in solution. The amino form has been found to be the predominant tautomer. The tautomeric barrier heights for water‐ and self‐assisted tautomerization reactions are significantly lower than that from the amino to imino form by the intramolecular proton transfer, showing the catalytic effect of water molecule(s) and the important role of 2‐aminothiazole itself for intermolecular proton transfer. Comparison between the tautomeric barriers demonstrates that the self‐association tautomerization through the dimerization is the most favorable pathway. Bulk solvent effects have been taken into account using the polarizable continuum model (PCM) of water and CCl4. The polar medium is favorable for the population of the imino form. The amino/imino equilibrium is also analyzed using the aromaticity index nucleus‐independent chemical shift (NICS); the NICS values for the amino form (about −10 ppm) are more negative than the imino species (about −8 ppm), showing that the amino form is more stable. The time‐dependent density functional theory (TDDFT) calculations of electronic absorption spectra suggest that the λmax of dimer is 255 nm. The oscillator strength of the imino forms is less than the amino form, and increases with the polarity of the solvents. All calculations for the tautomerization of 2‐aminothiazole are in reasonable line with the available experiments. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Efficient evaluation of Coulomb integrals in a mixed Gaussian and plane‐wave basis
Authors: Čársky Petr 
Published: August 2006

AbstractAn efficient way of calculation is presented for matrix elements between two plane waves interacting with a molecular Coulombic field. In concurrence with the absolute value of the momentum transfer vector, K = k1 − k2, the most effective method of calculation is selected. The case of K = 0 requires special treatment. For 0 < |K| ≤ 0.3, it is profitable to evaluate the integrals by means of the multipole expansion, and for |K| > 0.3 the density fitting can be applied. For the large |K| the electronic part of the integral is much smaller than the nuclear part and the integral may be approximated by the nuclear contribution only. Some examples for testing the accuracy and time saved are presented. The primary purpose of this paper is to accelerate electron scattering calculations, but it also may be profitable for the electronic structure theory in attempts to use mixed Gaussian and plane‐wave basis sets. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Lie algebraic method applied to a pulsed anharmonic oscillator
Authors: Récamier J. , Gorayeb M. , Mochán W. L. , Paz J. L. 
Published: August 2006

AbstractUsing nonlinear coherent states defined as approximate eigenstates of a deformed annihilation operator, we evaluate the response to a classical pulsed electric field of a system supporting a finite number of bound states. We calculate the temporal evolution of the average value of several observables like the momentum and the diplacement coordinate. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
New perspectives on unitary coupled‐cluster theory
Authors: Taube Andrew G. , Bartlett Rodney J. 
Published: August 2006

AbstractThe advantages and possibilities of a unitary coupled‐cluster (CC) theory are examined. It is shown that using a unitary parameterization of the wave function guarantees agreement between a sum‐over‐states polarization propagator and response theory calculation of properties of arbitrary order, as opposed to the case in conventional CC theory. Then, using the Zassenhaus expansion for noncommuting exponential operators, explicit diagrams for an extensive and variational method based on unitary CC theory are derived. Possible extensions to the approximations developed are discussed as well. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006
Anforderungen für ein Berechnungskonzept für die Bemessung punktgelagerter Verglasungen
Authors: Siebert Barbara 
Published: August 2006

AbstractIn diesem Beitrag werden allgemeine Anforderungen für ein Berechnungskonzept von punktgelagerten Verglasungen formuliert. Aufgrund der komplexen Eigenschaften im Punkthalterbereich ist eine schrittweise Verifizierung von Finite‐Element‐Berechnungen erforderlich, um realitätsnahe Ergebnisse erhalten zu können. Abschließend wird ein Verifizierungsmodell für punktgehaltene Scheiben vorgestellt, die im wesentlichen senkrecht zur Scheibenebene belastet werden.
Doppelverbundbrücken im Bau‐ und Endzustand
Authors: Ndogmo Joseph 
Published: August 2006

AbstractDoppelverbundbrücken werden aufgrund ihrer Wirtschaftlichkeit gegenüber Einfachverbundbrücken zur Zeit sehr oft bevorzugt gebaut. Anhand von einigen während der Bauausführung durchgeführten Messungen wird das Tragverhalten solcher Verbundbrücken erläutert. Dabei wird besonders auf die Fragen der Mitwirkung des Untergurtbetons im Bereich des Doppelverbundes sowie des Einflusses des Kriechens und des Schwindens auf die Schnittgrößenverteilung und Spannungsumlagerung eingegangen. Ebenso untersucht werden die Kraftüberleitung vom stählernen Kastenträger auf die Betonbodenplatte und die Schubkraftverteilung bei der flächigen Verbundwirkung im Bereich des Untergurtes sowie die Mitwirkung der Betonplatten (Fahrbahntafel und Untergurt) bei der Verteilung der Zustandsgrößen in Tragwerkslängsrichtung.
Reverse optical probing (ROPING) of neocortical circuits
Authors: Aaron Gloster , Yuste Rafael 
Published: August 2006

AbstractWe describe an optical technique to detect circuits of synaptically connected neurons. By combining calcium imaging of the spontaneous activity of neuronal populations with intracellular recordings from a given neuron, we perform a type of reverse correlation analysis to detect neurons that generate action potentials time‐locked to the synaptic currents of the recorded cell. This technique can quickly reveal monosynaptically connected neurons. Synapse 60:437–440, 2006. © 2006 Wiley‐Liss, Inc.
Novel processing aid based on modified Silly Putty®
Authors: Kulikov Oleg , Hornung Klaus 
Published: August 2006

AbstractA viscoelastic material based on low‐molecular‐weight silanols cured by boric acid, i.e., having a composition similar to that of the well‐known Silly Putty®, was used to delay sharkskin and stick–slip instabilities in the extrusion of linear low‐density polyethylene (LLDPE). The use of sodium hydroxide and phosphoric acid in the composition helped to improve adhesion of the material to metal and to extend its efficiency above 200°C. Adding powders of metal oxides, e.g., borax, silica, and especially silicates, further helped to delay the flow instabilities. A delay of the sharkskin instability to 25–35 times higher extrusion rates was achieved, and about 45% less pressure was observed in a screw extruder at the same throughput when this material was used as an additive to LLDPE (∼0.1%) or as a coating of the extrusion die. Tentative explanations of the sharkskin origin and for the delay of the instability are proposed. J. VINYL. ADDIT. TECHNOL., 12:131–142, 2006. © 2006 Society of Plastics Engineers
Suicide attempts among indigenous Sami adolescents and majority peers in Arctic Norway: Prevalence and associated risk factors
Authors: Silviken Anne , Kvernmo Siv 
Published: August 2006

AbstractThe prevalence of suicide attempts and associated risk factors such as sociodemographic conditions, emotional/behavioural problems and parent–child relationships were examined among 591 indigenous Sami and 2100 majority adolescents in Arctic Norway. There were no significant ethnic differences in prevalence of suicide attempts. In both ethnic groups, suicidal ideation, anxious/depressed problems and eating behaviour problems were associated with suicide attempts. Cross‐cultural differences in risk factors associated with suicide attempts existed. For Sami adolescents, factors diverging from the traditional cultural norms were associated with suicide attempts, such as alcohol intoxication, single‐parent home and paternal overprotection (p⩽.05). Vocational studies, not living together with parents, current smoking and experienced sexual intercourse were ethnic specific risk factors associated with suicide attempts among majority peers (p⩽.05). Clinicians should take into account that risk factors can differ between ethnic groups and should be sensitive to culturally divergent behaviour.
Sleep disturbances independently predict heart failure in overweight middle‐aged men
Authors: Ingelsson Erik , Lind Lars , Ärnlöv Johan , Sundström Johan 
Published: August 2006

AbstractBackgroundSleep disturbances are associated with manifest heart failure (HF). However, the relationship between sleep disturbances and incident HF has been less studied.AimsTo investigate self‐reported sleep disturbances as predictors of HF in a longitudinal, community‐based cohort of 2314 middle‐aged men.Methods and resultsData on self‐reported sleep disturbances, as well as established risk factors for HF were collected and analyzed using Cox proportional hazards analyses. In multivariable Cox proportional hazards models adjusted for established risk factors for HF, the presence at baseline of sleep disturbances (hazard ratio [HR], 1.52; 95% confidence interval [CI], 1.16–1.99; p=0.002) was an independent risk factor for HF. There was evidence of effect modification between BMI and sleep disturbances. In multivariable‐adjusted models, sleep disturbance (HR, 1.58; 95% CI, 1.13–2.21; p=0.008) was an independent risk factor for HF in overweight participants (BMI>25), but not in normal‐weight participants (BMI≤25). All results remained similar in a sub‐sample excluding all participants suffering from a myocardial infarction during follow‐up.ConclusionsSelf‐reported sleep disturbances imply an increased risk of subsequent HF in overweight middle‐aged men, via mechanisms largely independent of established risk factors for HF, including an interim myocardial infarction.
Holocene Climate Variability in Sicily from a Discontinuous Stalagmite Record and the Mesolithic to Neolithic Transition
Authors: Frisia Silvia , Borsato Andrea , Mangini Augusto , Spötl Christoph , Madonia Giuliana , Sauro Ugo 
Published: August 2006

AbstractFabric and stable isotopic composition of a Holocene stalagmite (CR1) from a cave in northern Sicily record changes in paleorainfall in the early Holocene. High δ13C stable isotope values in the calcite deposited from ca. 8500 to ca. 7500 yr ago are interpreted as reflecting periods of high rainfall. The wet phase was interrupted by two periods of multi-century duration characterized by relatively cool and dry winters centered at ca. 8200 and ca. 7500 yr ago, highlighted by low δ13C and δ18O values. A high variability of δ13C values is recorded from ca. 7500 to ca. 6500 yr ago and indicates that the transition from a pluvial early Holocene to the present-day climate conditions was punctuated by decadal-scale periods of relatively dry winters. In northern Sicily, the traditional elements of the Neolithic appear at ca. 7700 yr ago. It is possible that changes in rainfall influenced the passage from hunter-gathering to farming and sheep-herding economies.
Evaluation of epidermal growth factor receptor gene and chromosome 7 alterations in squamous cell carcinoma of the larynx, using chromogenic in situ hybridization on tissue microarrays
Authors: Tsiambas E , Stavrakis I , Lazaris A C , Karameris A , Patsouris E 
Published: August 2006

Aims: To identify subgroups of patients with squamous cell carcinoma (SCC) of the larynx, characterized by the specific deregulation mechanism of the epidermal growth factor receptor (EGFR) gene, and to evaluate EGFR protein expression levels and correlate these with biological and clinicopathological parameters.Materials and methods: Using tissue microarray technology, 50 formalin-fixed, paraffin-embedded primary laryngeal SCCs were cored and re-embedded into one block. Immunohistochemistry and chromogenic in situ hybridization were performed.Results: Epidermal growth factor receptor protein over-expression was observed in 27/50 (54 per cent) cases and was statistically associated with tumour grade (p=0.028). Epidermal growth factor receptor gene alterations were identified in 5/50 (10 per cent) cases, which demonstrated amplification (n=4) and deletion (n=1). Chromosome 7 instability was detected in 8/50 (16 per cent) cases.Conclusions: Epidermal growth factor receptor over-expression is a frequent event in SCCs, but it does not predict a specific molecular mechanism of gene deregulation for targeted therapeutic strategies via monoclonal antibodies.
Locating the scala media in the fixed human temporal bone for therapeutic access: a preliminary study
Authors: Pau H , Fagan P , Oleskevich S 
Published: August 2006

Objective: To investigate the location of the scala media in relation to the round window niche in human temporal bones.Design: Ten human temporal bones were investigated by radical mastoidectomy and promontory drill-out.Setting: Temporal bone laboratory.Outcome measures: The distance from the scala media to the anterior edge of the round window niche, measured by Fisch's stapedectomy measuring cylinders.Results: The scala media was identified at the transection point of a vertical line 1.6 to 2.2 mm (mean=1.8 mm; standard deviation=0.2) anterior to the anterior edge of the round window niche and a horizontal line 0.2 mm inferior to the lower border of the oval window.Conclusion: This report demonstrates the point of entry into the scala media via the promontory in fixed temporal bone models, which may provide a site of entry for stem cells and gene therapy insertion.
Reliable gene signatures for microarray classification: assessment of stability and performance
Authors: Davis Chad A. , Gerick Fabian , Hintermair Volker , Friedel Caroline C. , Fundel Katrin , Küffner Robert , Zimmer Ralf 
Published: August 2006

Abstract
Motivation: Two important questions for the analysis of gene expression measurements from different sample classes are (1) how to classify samples and (2) how to identify meaningful gene signatures (ranked gene lists) exhibiting the differences between classes and sample subsets. Solutions to both questions have immediate biological and biomedical applications. To achieve optimal classification performance, a suitable combination of classifier and gene selection method needs to be specifically selected for a given dataset. The selected gene signatures can be unstable and the resulting classification accuracy unreliable, particularly when considering different subsets of samples. Both unstable gene signatures and overestimated classification accuracy can impair biological conclusions.
Methods: We address these two issues by repeatedly evaluating the classification performance of all models, i.e. pairwise combinations of various gene selection and classification methods, for random subsets of arrays (sampling). A model score is used to select the most appropriate model for the given dataset. Consensus gene signatures are constructed by extracting those genes frequently selected over many samplings. Sampling additionally permits measurement of the stability of the classification performance for each model, which serves as a measure of model reliability.
Results: We analyzed a large gene expression dataset with 78 measurements of four different cartilage sample classes. Classifiers trained on subsets of measurements frequently produce models with highly variable performance. Our approach provides reliable classification performance estimates via sampling. In addition to reliable classification performance, we determined stable consensus signatures (i.e. gene lists) for sample classes. Manual literature screening showed that these genes are highly relevant to our gene expression experiment with osteoarthritic cartilage. We compared our approach to others based on a publicly available dataset on breast cancer.
Availability: R package at
Contact: ralf.zimmer@bio.ifi.lmu.de
Local similarity analysis reveals unique associations among marine bacterioplankton species and environmental factors
Authors: Ruan Quansong , Dutta Debojyoti , Schwalbach Michael S. , Steele Joshua A. , Fuhrman Jed A. , Sun Fengzhu 
Published: August 2006

Abstract
Motivation: Characterizing the diversity of microbial communities and understanding the environmental factors that influence community diversity are central tenets of microbial ecology. The development and application of cultivation independent molecular tools has allowed for rapid surveying of microbial community composition at unprecedented resolutions and frequencies. There is a growing need to discern robust patterns and relationships within these datasets which provide insight into microbial ecology. Pearson correlation coefficient (PCC) analysis is commonly used for identifying the linear relationship between two species, or species and environmental factors. However, this approach may not be able to capture more complex interactions which occur in situ; thus, alternative analyses were explored.
Results: In this paper we introduced local similarity analysis (LSA), which is a technique that can identify more complex dependence associations among species as well as associations between species and environmental factors without requiring significant data reduction. To illustrate its capability of identifying relationships that may not otherwise be identified by PCC, we first applied LSA to simulated data. We then applied LSA to a marine microbial observatory dataset and identified unique, significant associations that were not detected by PCC analysis. LSA results, combined with results from PCC analysis were used to construct a theoretical ecological network which allows for easy visualization of the most significant associations. Biological implications of the significant associations detected by LSA were discussed. We also identified additional applications where LSA would be beneficial.
Availability: The algorithms are implemented in Splus/R and they are available upon request from the corresponding author.
Contact: fsun@usc.edu
‘EXAMEN D'IDENTITÉ’: VOYAGEUR PROFESSIONNEL ET IDENTIFICATION DIASPORIQUE CHEZ JEAN-PHILIPPE TOUSSAINT ET ABDELKÉBIR KHATIBI
Authors: Hennuy Jean-Frédéric 
Published: August 2006

Abstract

À travers la question du rapport à l'autre et à soi-même, la lecture des romans de Jean-Philippe Toussaint et Abdelkébir Khatibi nous forcent à une analyse où l'on est appelé à redoubler de vigilance face à des certitudes identitaires considèrèes, bien trop souvent encore, comme inébranlables et indéfectibles. Jean-Philippe Toussaint et Abdelkébir Khatibi nous rendent sensibles au fait qu'en début de ce troisième millénaire notre identité personnelle est toujours
déterritorialisée
. Nos voyages, nos traversées chroniques des frontières ne visent plus à fonder des territoires, mais nous forcent à faire en permanence l'examen de notre identité, à créer des
identités diasporiques
. Identitaires, nos voyages le sont parce qu'ils nous contraignent à former et reformer une carte d'identité composée d'une multiplicité d'appartenances. Identitaires, nos voyages le sont aussi et avant tout parce qu'ils nous mettent face au caractère protéiforme de notre étrangeté.