Showing papers by "University of Mons published in 2007"
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TL;DR: In this article, the authors present a detailed analysis of the performance of the Large Hadron Collider (CMS) at 14 TeV and compare it with the state-of-the-art analytical tools.
Abstract: CMS is a general purpose experiment, designed to study the physics of pp collisions at 14 TeV at the Large Hadron Collider (LHC). It currently involves more than 2000 physicists from more than 150 institutes and 37 countries. The LHC will provide extraordinary opportunities for particle physics based on its unprecedented collision energy and luminosity when it begins operation in 2007. The principal aim of this report is to present the strategy of CMS to explore the rich physics programme offered by the LHC. This volume demonstrates the physics capability of the CMS experiment. The prime goals of CMS are to explore physics at the TeV scale and to study the mechanism of electroweak symmetry breaking--through the discovery of the Higgs particle or otherwise. To carry out this task, CMS must be prepared to search for new particles, such as the Higgs boson or supersymmetric partners of the Standard Model particles, from the start-up of the LHC since new physics at the TeV scale may manifest itself with modest data samples of the order of a few fb−1 or less. The analysis tools that have been developed are applied to study in great detail and with all the methodology of performing an analysis on CMS data specific benchmark processes upon which to gauge the performance of CMS. These processes cover several Higgs boson decay channels, the production and decay of new particles such as Z' and supersymmetric particles, Bs production and processes in heavy ion collisions. The simulation of these benchmark processes includes subtle effects such as possible detector miscalibration and misalignment. Besides these benchmark processes, the physics reach of CMS is studied for a large number of signatures arising in the Standard Model and also in theories beyond the Standard Model for integrated luminosities ranging from 1 fb−1 to 30 fb−1. The Standard Model processes include QCD, B-physics, diffraction, detailed studies of the top quark properties, and electroweak physics topics such as the W and Z0 boson properties. The production and decay of the Higgs particle is studied for many observable decays, and the precision with which the Higgs boson properties can be derived is determined. About ten different supersymmetry benchmark points are analysed using full simulation. The CMS discovery reach is evaluated in the SUSY parameter space covering a large variety of decay signatures. Furthermore, the discovery reach for a plethora of alternative models for new physics is explored, notably extra dimensions, new vector boson high mass states, little Higgs models, technicolour and others. Methods to discriminate between models have been investigated. This report is organized as follows. Chapter 1, the Introduction, describes the context of this document. Chapters 2-6 describe examples of full analyses, with photons, electrons, muons, jets, missing ET, B-mesons and τ's, and for quarkonia in heavy ion collisions. Chapters 7-15 describe the physics reach for Standard Model processes, Higgs discovery and searches for new physics beyond the Standard Model
973 citations
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TL;DR: In this paper, the capabilities of the CERN Large Hadron Collider (LHC) experiment to explore the rich heavy-ion physics program offered by the LHC are presented, and the potential of the CMS experiment to carry out a series of representative Pb-Pb measurements.
Abstract: This report presents the capabilities of the CMS experiment to explore the rich heavy-ion physics programme offered by the CERN Large Hadron Collider (LHC). The collisions of lead nuclei at energies , will probe quark and gluon matter at unprecedented values of energy density. The prime goal of this research is to study the fundamental theory of the strong interaction ? Quantum Chromodynamics (QCD) ? in extreme conditions of temperature, density and parton momentum fraction (low-x).This report covers in detail the potential of CMS to carry out a series of representative Pb-Pb measurements. These include bulk observables, (charged hadron multiplicity, low pT inclusive hadron identified spectra and elliptic flow) which provide information on the collective properties of the system, as well as perturbative probes such as quarkonia, heavy-quarks, jets and high pT hadrons which yield tomographic information of the hottest and densest phases of the reaction.
361 citations
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TL;DR: In this paper, a high-performance magnetic resonance imaging T-2 contrast agent has been prepared via phase transfer of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) to an aqueous solution.
Abstract: A high-performance magnetic resonance imaging T-2 contrast agent has been prepared via phase transfer of hydrophobic superparamagnetic iron oxide nanoparticles (SPIONs) to an aqueous solution by us ...
233 citations
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TL;DR: This paper proposes the technique of critical pair analysis to detect the implicit dependencies between refactorings, and the results of this analysis can help the developer to make an informed decision of which refactoring is most suitable in a given context and why.
Abstract: Refactoring is a widely accepted technique to improve the structure of object-oriented software. Nevertheless, existing tool support remains restricted to automatically applying refactoring transformations. Deciding what to refactor and which refactoring to apply still remains a difficult manual process, due to the many dependencies and interrelationships between relevant refactorings. In this paper, we represent refactorings as graph transformations, and we propose the technique of critical pair analysis to detect the implicit dependencies between refactorings. The results of this analysis can help the developer to make an informed decision of which refactoring is most suitable in a given context and why. We report on several experiments we carried out in the AGG graph transformation tool to support our claims.
165 citations
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115 citations
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TL;DR: In this article, the influence of carbon nanotubes on photodegradation of EVA/carbon nanotube nanocomposites was studied by irradiation under photooxidative conditions (at λ > 300 nm, at 60 °C and in the presence of oxygen).
109 citations
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TL;DR: In this article, high-density polyethylene coated multiwalled carbon nanotubes (c-MWNTs) and multi-walled carbon nanotsubes (MWNT) have been dispersed into an ethylene vinyl acetate (EVA) copolymer by mechanical kneading.
Abstract: High-density polyethylene coated multiwalled carbon nanotubes (c-MWNTs) and multiwalled carbon nanotubes (MWNTs) have been dispersed into an ethylene vinyl acetate (EVA) copolymer by mechanical kneading. The effect of c-MWNTs on tensile properties, thermo-oxidative degradation, and fire behavior has been studied in comparison with virgin EVA and EVA/MWNTs nanocomposites. Due to the better dispersion of the coated nanotubes, the incorporation of 3 wt % of c-MWNTs leads to an increase of the Young's modulus, the cohesion of the combustion residues, and a decrease of the peak heat-release rate.
106 citations
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TL;DR: In this article, the influence of the nature of carbon nanotubes on the fire behavior of the composites, especially previous MWNTs crushing proved to substantially delay the TTI while maintaining much reduced heat release rate (HRR).
Abstract: Nanocomposites based on an ethylene-vinyl acetate copolymer (27 wt.-% vinyl acetate) and multiwall carbon nanotubes (MWNTs) have been prepared by melt blending and their thermal degradation and flame retardant properties have been evaluated. Special attention has been paid to the influence of the nanotube nature on the flammability properties and more particularly on the time to ignition (TTI) as measured by cone calorimetry. It has been shown that there is a strong influence of the nature of carbon nanotubes on the fire behaviour of the composites, especially previous MWNTs crushing proved to substantially delay the TTI while maintaining much reduced heat release rate (HRR). Such a remarkable behaviour might be explained by the chemical reactivity of radical species present at the surface/extremities of crushed MWNTs during the combustion process.
105 citations
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TL;DR: The existence of residual stress due to strongly out of equilibrium chain conformations and a reduced entanglement density resulting from film preparation by spin coating is demonstrated.
Abstract: Performing detailed studies of viscoelastic dewetting of thin polystyrene films on solid substrates, we demonstrate the existence of residual stress due to strongly out of equilibrium chain conformations and a reduced entanglement density resulting from film preparation by spin coating. The ratio of stress over elastic modulus was found to increase strongly with decreasing film thickness and increasing chain length. Full equilibration of chain conformations required long times comparable to bulk reptation times. However, for chains longer than about 3000 monomers, the residual stress relaxed faster, at a rate independent of chain length.
104 citations
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TL;DR: In this article, an upper bound of E-2 Phi(90%C.L.) < 7.4x10(-8) GeV cm(-2) s(-1) sr(-1).
Abstract: A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent live time of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with nonthermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E-2 Phi(90%C.L.)< 7.4x10(-8) GeV cm(-2) s(-1) sr(-1) is placed on the diffuse flux of muon neutrinos with a Phi proportional to E-2 spectrum in the energy range 16 TeV to 2.5 PeV. This is currently the most sensitive Phi proportional to E-2 diffuse astrophysical neutrino limit. We also set upper limits for astrophysical and prompt neutrino models, all of which have spectra different from Phi proportional to E-2.
102 citations
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TL;DR: The available atomic data used for interpreting and modeling x-ray observations can be divided into several levels of detail, ranging from compilations which can be used with direct inspection of raw data, such as line finding lists, to synthetic spectra which attempt to fit to an entire observed dataset simultaneously as mentioned in this paper.
Abstract: The available atomic data used for interpreting and modeling x-ray observations are reviewed The applications for these data can be divided into several levels of detail, ranging from compilations which can be used with direct inspection of raw data, such as line finding lists, to synthetic spectra which attempt to fit to an entire observed dataset simultaneously This review covers cosmic sources driven by both electron ionization and photoionization and touches briefly on planetary surfaces and atmospheres The applications to x-ray astronomy, the available data, and recommendations for astronomical users are all reviewed, and an attempt to point out the applications where the shortcomings are greatest is also given
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TL;DR: The hypothesis that B. niveatus and B. vorticosus should be regarded as conspecific is supported and this approach may help future studies not only by contributing towards solving problems in systematics but also in understanding the flight mechanism of bumblebees.
Abstract: Summary B. (Sibiricobombus) niveatus and B. (Sibiricobombus) vorticosus are analyzed and compared with selected species of the subgenera Melanobombus and Mendacibombus. Different geometric morphometric methods based on wings landmark data show that there are no morphological differences between B. niveatus and B. vorticosus. These results support the hypothesis that B. niveatus and B. vorticosus should be regarded as conspecific. On the other hand, the wing shapes show significant differences among the bumblebee species and subgenera that are coherent with their specific and subgeneric status. This approach may help future studies not only by contributing towards solving problems in systematics but also in understanding the flight mechanism of bumblebees. It also supports studies on the evolution of crossvein structure and on aerodynamics of different wing shapes in insects.
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01 Oct 2007TL;DR: The cost-optimal reachability problem for weighted timed automata such that positive and negative costs are allowed on edges and locations is studied, and an extension of the region graph, the weighted discrete graph, is proposed, whose structure gives light on the way to solve the cost-optimality problem.
Abstract: We study the cost-optimal reachability problem for weighted timed automata such that positive and negative costs are allowed on edges and locations. By optimality, we mean an infimum cost as well as a supremum cost. We show that this problem is PSpace-Complete. Our proof uses techniques of linear programming, and thus exploits an important property of optimal runs: their time-transitions use a time τ which is arbitrarily close to an integer. We then propose an extension of the region graph, the weighted discrete graph, whose structure gives light on the way to solve the cost-optimal reachability problem. We also give an application of the cost-optimal reachability problem in the context of timed games.
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TL;DR: Various recent results based on novel approaches for the self-assembly of multicomponent 2D nanostructures at the solid–liquid interface and their characterization on the submolecular scale by in situ STM studies are highlighted.
Abstract: Achieving full, nanometer-scale control over the positioning and organization of molecules into monolayers at surfaces represents a major challenge, with potential interest in the field of fabrication of multifunctional nanodevices. Bottom-up approaches successfully exploit the self-assembly of molecules to generate preprogrammed structures and patterns on such a scale. In this context, scanning tunneling microsACHTUNGTRENNUNGcopy (STM) is a tool of choice to characterize the molecular packing on solid surfaces and unravel dynamic processes such as organic monolayer formation, in particular at the solid–liquid interface. 10] While the formation of single-component self-assembled monolayers and their characterization by STM has been thoroughly reported for more than a decade, only recently have interesting studies on multicomponent two-dimensional (2D) architectures been proposed. In this contribution we highlight various recent results based on novel approaches for the self-assembly of multicomponent 2D nanostructures at the solid–liquid interface and their characterization on the submolecular scale by in situ STM studies. The controlled formation of ordered multicomponent nanostructures with a periodic structural motif is not trivial as most binary mixtures are prone to undergo phase segregation or to form randomly mixed domains. Ordered bior multicomponent nanostructures can be formed by a subtle interplay between intramolecular, intermolecular, and interfacial interactions, and in particular by combining principles of supramolecular chemistry and interfacial chemistry. An important role is played by the solvent, not only in view of its different interactions with the molecules, but also in light of the possibility to coadsorb at surfaces. For example, De Feyter and co-workers observed the coadsorption of solvent (1-octanol) molecules within a monoACHTUNGTRENNUNGlayer of an isophtalic acid derivative (the “studied” molecule) on highly oriented pyrolytic graphite (HOPG). They showed the exchange dynamics between 1-octanol solvent molecules and the isophtalic acid proceeds at the monolayer domain boundaries, leading to a rearrangement of a large part of the monolayer within a domain in a cooperative manner (see details in Ref. [14]). Such a result is in line with the findings of Padowitz and co-workers, who employed thioether molecules coadsorbed within an alkane monolayer as tracers to follow the rate of exchange (adsorption–desorption processes) and the specific molecular processes at grain boundaries. Recently, a few STM studies reported the construction of mixed donor–acceptor monolayers by applying a solution containing the two molecular systems to crystalline solid surfaces such as HOPG. In a seminal work, Rabe and coworkers studied the monolayer formation of a donor–acceptor model system, namely isophtalic acid and pyrazine derivatives, forming hydrogen-bonded 2D networks on graphite, and compared the structure with a 3D crystalline [*] Dr. P. Samor Istituto per la Sintesi Organica e la Fotoreattivit Consiglio Nazionale delle Ricerche (C.N.R.) via Gobetti 101, 40129 Bologna (Italy) Fax: (+39)051-6399844 E-mail: samori@isof.cnr.it
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TL;DR: In this paper, the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos were reported, performed on the data collected with the AMANDA-II neutrino tele...
Abstract: We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino tele ...
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TL;DR: In this paper, a new and simple method to orient the wrinkles by chemically patterning the substrate with regions of high and low adhesion was proposed, which is based on the concept of wrinkles at the metallized surface of thin polymer films.
Abstract: Wrinkling patterns at the metallized surface of thin polymer films are shown to be sensitive to the sticky or slippery character of the polymer-substrate interface. Existing theoretical models were expanded to specific boundary conditions (adhesive versus slippery) in order to rationalize these observations. Based on this concept, we were able to propose a new and simple method to orient the wrinkles by chemically patterning the substrate with regions of high and low adhesion.
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TL;DR: It is concluded that a P-glycoprotein homologue transporter is probably involved in heme transport through the plasma membrane because heme internalization proceeded much faster than that observed by hemoglobin-rhodamine.
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TL;DR: For the first time, a general, purely algebraic understanding of the universal structure of the Weyl anomalies is obtained, in arbitrary dimensions and independently of any regularization scheme.
Abstract: Conformally invariant systems involving only dimensionless parameters are known to describe particle physics at very high energy. In the presence of an external gravitational field, the conformal symmetry may generalize to the Weyl invariance of classical massless field systems in interaction with gravity. In the quantum theory, the latter symmetry no longer survives: A Weyl anomaly appears. Anomalies are a cornerstone of quantum field theory, and, for the first time, a general, purely algebraic understanding of the universal structure of the Weyl anomalies is obtained, in arbitrary dimensions and independently of any regularization scheme.
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TL;DR: It is proved that for countable scattered linear orderings, the two notions of finite automata and rational expressions are equivalent, which extends Kleene's theorem.
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TL;DR: Immunohistochemical data reported in this study point to the expression of FXR in human breast cancer and show that the latter receptor functionally interacts with ER.
Abstract: Farnesoid X receptor (FXR) is a metabolic nuclear receptor expressed in the liver and traditionally considered as a bile acid sensor. Yet, FXR has been recently demonstrated in other tissues and cells, such as the kidneys, the adrenals, and arterial smooth muscle cells. Immunohistochemical data reported in this study point to the expression of FXR in human breast cancer. In addition, FXR expression was also found by Western blotting and immunofluorescence microscopy in breast-cancer-derived cell lines MCF-7 (estrogen receptor [ER]-positive) and MDA-MB-231 (ER-negative). The FXR activator farnesol, a mevalonate pathway intermediate, exerts a mitogenic effect on MCF-7 cells. The growth stimulation is completely suppressed by antiestrogens. In contrast, MDA-MB-231 cells appear farnesol-insensitive, suggesting an involvement of ER in farnesol mitogenicity. In accordance with this interpretation, farnesol induces in MCF-7 cells a decrease of ER level, consistent with a phenomenon of receptor downregulation. Farnesol also increases progesterone receptor (PgR) expression in MCF-7 cells and stimulates ER-mediated gene transactivation in MVLN cells (MCF-7 cells stably transfected with an ER reporter gene). Of note, both effects of farnesol on ER expression and activity are completely suppressed by antiestrogens. In addition, farnesol-induced PgR is markedly reduced by FXR gene silencing (siRNA), demonstrating the involvement of FXR in the estrogenic effects of farnesol. Finally, coimmunoprecipitation experiments (FXR immunoprecipitation followed by Western blot analysis of ER in the immunoprecipitate) produced definite evidence that FXR interacts with ER. Altogether, these observations reveal the hitherto unreported presence of FXR in breast cancer and show that the latter receptor functionally interacts with ER. The occurrence of such a crosstalk calls for some caution regarding the pharmacological use of FXR agonists.
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TL;DR: In this article, the molecular-kinetic theory of wetting (MKT) was used to interpret the dynamic contact angle data and evaluate the contact-line friction ζ0 at the microscopic scale.
Abstract: Forced wetting experiments with various liquids were conducted to study the dynamic wetting properties of nylon filament. The molecular-kinetic theory of wetting (MKT) was used to interpret the dynamic contact angle data and evaluate the contact-line friction ζ0 at the microscopic scale. By taking account of the viscosity of the liquid, ζ0 could be related exponentially to the reversible work of adhesion. This clearly establishes an experimental link between the static and dynamic wetting properties of the material. Moreover, statistical analysis of the equilibrium molecular displacement frequency K0 and the length of the displacements λ reveals that these two fundamental parameters of the MKT are strongly correlated, not only in the linearized form of the theory (valid close to equilibrium) but also when the nonlinear form of the equations has to be considered at higher wetting speeds.
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TL;DR: This article formalised the behaviour specified by UML 2.0 sequence and protocol state machine diagrams and showed how the reasoning capabilities of description logics, a decidable fragment of first-order logic, can be used in a natural way to detect behaviour inconsistencies.
Abstract: Model-driven engineering is an emerging software engineering approach that relies on model transformation. Typical kinds of model transformations are model refinement and model refactoring. Whenever such a transformation is applied to a consistent model, we would like to know whether the consistency is preserved by the transformation. Therefore, in this article, we formally define and explore the relation between behaviour inheritance consistency of a refined model with respect to the original model, and behaviour preservation of a refactored model with respect to the original model. As it turns out, there is a strong similarity between these notions of behaviour consistency and behaviour preservation. To illustrate this claim, we formalised the behaviour specified by UML 2.0 sequence and protocol state machine diagrams. We show how the reasoning capabilities of description logics, a decidable fragment of first-order logic, can be used in a natural way to detect behaviour inconsistencies. These reasoning capabilities can be used in exactly the same way to detect behaviour preservation violations during model refactoring. A prototype plug-in in a UML CASE tool has been developed to validate our claims.
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TL;DR: Findings have clinical relevance in identifying which symptoms will be triggered by steep transitions of E2 such as sudden withdrawal and which health parameters may require a maintenance level of E 2.
Abstract: Changes in FSH and estradiol (E2) across the menopausal transition are clearly not linear. The present study utilizes data from 204 women who completed the 13-year prospective Melbourne Women's Midlife Health Project. E2, FSH, symptoms, self-rated health, mood, sexual function and coronary heart disease (CHD) risk were measured longitudinally. We presumed an s-shaped curve for each hormone and estimated five parameters for each hormone curve for each woman: baseline, final value, range, slope at inflexion point and age at inflexion point. These parameters were found to adequately estimate the curve for each hormone. The median age of transition observed for E2 occurs >1 year later than the median age of transition observed for FSH. FSH parameters did not affect any of the health outcomes analysed. Hot flushes, night sweats, sleeping problems, vaginal dryness and to a lesser extent self-rated health were highly significantly associated with E2 range and slope. Sexual response and CHD risk were highly significantly associated with final E2 level (post-menopausally). These findings have clinical relevance in identifying which symptoms will be triggered by steep transitions of E2 such as sudden withdrawal and which health parameters may require a maintenance level of E2.
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TL;DR: In this paper, two conjugated oligomers, representing elementary segments of fluorene-thiophene copolymers, are compared in terms of the microscopic morphology and the optical properties of thin deposits.
Abstract: Two conjugated oligomers, representing elementary segments of fluorene–thiophene copolymers, are compared in terms of the microscopic morphology and the optical properties of thin deposits. The atomic force microscopy morphological data and the solid-state absorption and emission spectra are interpreted in terms of the assembly of the conjugated molecules. The compound with a terthiophene central unit and fluorene end-groups shows well-defined monolayer-by-monolayer assembly into micrometer-long stripe-like structures, with a crystalline herringbone-type organization within the monolayers. Polarized confocal microscopy indicates a strong orientation of the crystalline domains within the stripes. In contrast, the compound with a terfluorene central unit and thiophene end groups forms no textured aggregates and the optical spectra in the solid-state are very similar to those recorded in solution, suggesting that the molecules interact only weakly in the solid. The difference in behaviour between the two compounds most probably originates from their different capability to form densely-packed assemblies of interacting π-systems.
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TL;DR: The impact on this parameter of the backbone flexibility present in oligothiophenes as a result of inter-ring torsional motions as well as gas-phase ultraviolet photoelectron spectroscopy calculations are investigated.
Abstract: Density functional theory calculations together with highly resolved gas-phase ultraviolet photoelectron spectroscopy have been applied to oligothiophene chains with up to eight thiophene rings. One of the important parameters governing the charge transport properties in the condensed phase is the amount of energy relaxation upon ionization. Here, we investigate the impact on this parameter of the backbone flexibility present in oligothiophenes as a result of inter-ring torsional motions. With respect to oligoacenes that are characterized by a coplanar and rigid backbone, the torsional flexibility in oligothiophenes adds to the relaxation energy and leads to the broadening of the first ionization peak, making its analysis more complex.
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TL;DR: In this article, the general solutions of the Wess-Zumino consistency condition for the Weyl anomalies are derived in a purely algebraic manner by explicitly computing the cohomology of the corresponding Becchi-Rouet-Stora-Tyutin differential in the space of integrated local functions at ghost number unity.
Abstract: The general solutions of the Wess-Zumino consistency condition for the Weyl anomalies are derived in a purely algebraic manner. The solutions are obtained, in arbitrary dimensions, by explicitly computing the cohomology of the corresponding Becchi-Rouet-Stora-Tyutin differential in the space of integrated local functions at ghost number unity.
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TL;DR: In this article, the influence of the matrix polarity, related here to the relative content in vinyl acetate units, on the mechanical properties has been studied, by comparing the tensile properties of the nanocomposites to those of the unfilled matrices.
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TL;DR: In this article, it was shown that the set of continuous interpolating functions with big algebras contains a big algebraic structure, and that the Dirichlet series of continuous functions have a big algebraic structure as well.
Abstract: We show that the set of continuous nowhere differentiable functions, the set of Dirichlet series which are bounded in the right half-plane and diverge everywhere on the imaginary axis, and the set of continuous interpolating functions contain big algebras.
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TL;DR: This Feature Article is focused on two AFM modes, i.e. conducting and Kelvin probe force microscopies, which allow the study of electrical and electronic properties of organic thin films, respectively.