7,589 research outputs found

    Collapse of triaxial bright solitons in atomic Bose-Einstein condensates

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    We study triaxial bright solitons made of attractive Bose-condensed atoms characterized by the absence of confinement in the longitudinal axial direction but trapped by an anisotropic harmonic potential in the transverse plane. By numerically solving the three-dimensional Gross-Pitaevskii equation we investigate the effect of the transverse trap anisotropy on the critical interaction strength above which there is the collapse of the condensate. The comparison with previous predictions [Phys. Rev. A {\bf 66}, 043619 (2002)] shows significant differences for large anisotropies.Comment: Accepted for the publication in Phys. Lett.

    BonFIRE: A multi-cloud test facility for internet of services experimentation

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    BonFIRE offers a Future Internet, multi-site, cloud testbed, targeted at the Internet of Services community, that supports large scale testing of applications, services and systems over multiple, geographically distributed, heterogeneous cloud testbeds. The aim of BonFIRE is to provide an infrastructure that gives experimenters the ability to control and monitor the execution of their experiments to a degree that is not found in traditional cloud facilities. The BonFIRE architecture has been designed to support key functionalities such as: resource management; monitoring of virtual and physical infrastructure metrics; elasticity; single document experiment descriptions; and scheduling. As for January 2012 BonFIRE release 2 is operational, supporting seven pilot experiments. Future releases will enhance the offering, including the interconnecting with networking facilities to provide access to routers, switches and bandwidth-on-demand systems. BonFIRE will be open for general use late 2012

    Characterisation of retrotransposon insertion polymorphisms in whole genome sequencing data from individuals with amyotrophic lateral sclerosis

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    The genetics of an individual is a crucial factor in understanding the risk of developing the neurodegenerative disease amyotrophic lateral sclerosis (ALS). There is still a large proportion of the heritability of ALS, particularly in sporadic cases, to be understood. Among others, active transposable elements drive inter-individual variability, and in humans long interspersed element 1 (LINE1, L1), Alu and SINE-VNTR-Alu (SVA) retrotransposons are a source of polymorphic insertions in the population. We undertook a pilot study to characterise the landscape of non-reference retrotransposon insertion polymorphisms (non-ref RIPs) in 15 control and 15 ALS individuals’ whole genomes from Project MinE, an international project to identify potential genetic causes of ALS. The combination of two bioinformatics tools (mobile element locator tool (MELT) and TEBreak) identified on average 1250 Alu, 232 L1 and 77 SVA non-ref RIPs per genome across the 30 analysed. Further PCR validation of individual polymorphic retrotransposon insertions showed a similar level of accuracy for MELT and TEBreak. Our preliminary study did not identify a specific RIP or a significant difference in the total number of non-ref RIPs in ALS compared to control genomes. The use of multiple bioinformatic tools improved the accuracy of non-ref RIP detection and our study highlights the potential importance of studying these elements further in ALS

    A New Feature Extraction Technique Based on 1D Local Binary Pattern for Gear Fault Detection

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    Gear fault detection is one of the underlying research areas in the field of condition monitoring of rotating machines. Many methods have been proposed as an approach. One of the major tasks to obtain the best fault detection is to examine what type of feature(s) should be taken out to clarify/improve the situation. In this paper, a new method is used to extract features from the vibration signal, called 1D local binary pattern (1D LBP). Vibration signals of a rotating machine with normal, break, and crack gears are processed for feature extraction. The extracted features from the original signals are utilized as inputs to a classifier based onNearest Neighbour ( -NN) and Support Vector Machine (SVM) for three classes (normal, break, or crack). The effectiveness of the proposed approach is evaluated for gear fault detection, on the vibration data obtained from the Prognostic Health Monitoring (PHM'09) Data Challenge. The experiment results show that the 1D LBP method can extract the effective and relevant features for detecting fault in the gear. Moreover, we have adopted the LOSO and LOLO cross-validation approaches to investigate the effects of speed and load in fault detection

    A New Neutrosophic Cognitive Map with Neutrosophic Sets on Connections

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    Neutrosophic sets and their application to decision support have become a very important topic. In real situations, there are different sources of indeterminacy. This paper suggests a new decision-making model based on Neutrosophic Cognitive Maps (NCMs) for making comprehensive decisions from a multi-objective approach (diagnosis, decisions, and prediction) during the execution of many projects simultaneously. A Soft Computing technique like Fuzzy Cognitive Maps (FCMs) has been widely used for decision-making process in project management, but this technique has the limitation of not considering the indeterminacy between concepts. This limitation is overcome by the proposed model since NCMs can represent the indeterminacy or neutrality. The new model includes neutrosophic sets in the map’s connections. Finally, the suggested model has been compared with traditional FCM-based model considering efficiency and efficacy

    Dynamics of a classical gas including dissipative and mean field effects

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    By means of a scaling ansatz, we investigate an approximated solution of the Boltzmann-Vlasov equation for a classical gas. Within this framework, we derive the frequencies and the damping of the collective oscillations of a harmonically trapped gas and we investigate its expansion after release of the trap. The method is well suited to studying the collisional effects taking place in the system and in particular to discussing the crossover between the hydrodynamic and the collisionless regimes. An explicit link between the relaxation times relevant for the damping of the collective oscillations and for the expansion is established.Comment: 4 pages, 1 figur

    A C60-aryne building block:synthesis of a hybrid all-carbon nanostructure

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    The synthesis of a [60]fullerene-benzyne building block and its further chemical cycloaddition reaction with graphene has resulted in a new all-carbon hybrid material which has been characterized by TGA, FTIR and Raman spectroscopies, XPS as well as TEM. Based on computational studies,the formation of both [2+2] and [4+2] cycloadducts on the graphene surface is feasible

    Exact results on the dynamics of multi-component Bose-Einstein condensate

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    We study the time-evolution of the two dimensional multi-component Bose-Einstein condensate in an external harmonic trap with arbitrary time-dependent frequency. We show analytically that the time-evolution of the total mean-square radius of the wave-packet is determined in terms of the same solvable equation as in the case of a single-component condensate. The dynamics of the total mean-square radius is also the same for the rotating as well as the non-rotating multi-component condensate. We determine the criteria for the collapse of the condensate at a finite time. Generalizing our previous work on a single-component condensate, we show explosion-implosion duality in the multi-component condensate.Comment: Two-column 6 pages, RevTeX, no figures(v1); Added an important reference, version to appear in Physical Review A (v2

    The potential of flavonoids as natural antioxidants and UV light stabilizers for polypropylene

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    This article presents a study on the stabilization of polypropylene against thermo-oxidation and UV radiation by using natural phenolic compounds derived from the structures of flavonoids: a flavone (chrysin), a flavanol (quercetin), two flavanone glycosides (hesperidin and naringin), and flavanoligand (silibinin). Thermal stabilization has been assessed in an oxidizing atmosphere by means of differential scanning calorimetry both in isothermal and in dynamic conditions. In addition, the effectiveness of these phenolic compounds as thermal stabilizers at high temperature has been quantified with the use of thermogravimetric analysis. Stabilization against UV radiation has been estimated by studying the morphology changes of the exposed surfaces by scanning electron microscope (SEM); also, surface chemical changes have been followed by infrared spectroscopy. Global results show that flavonoid compounds of type flavonols (quercetin and silibinin) provide the best results in stabilizing both against oxidation and against the action of UV radiation. (c) 2012 Wiley Periodicals, Inc.This study is part of the project IPT-310000-2010-037, "ECOTEX-COMP: Research and development of textile structures useful as reinforcement of composite materials with marked ecological character" funded by the "Ministerio de Ciencia e Innovacion," with an aid of 189540.20 euros, within the "Plan Nacional de Investigacion Cientifica, Desarrollo e Innovacion Tecnologica 2008-2011" and funded by the European Union through FEDER funds, "Technology Fund 2007-2013, Operational Programme on R+D+i for and on behalf of the companies." Also, Generalitat Valenciana Ref: ACOMP/2012/087 is acknowledged for financial support.Samper Madrigal, MD.; Fages, E.; Fenollar Gimeno, OÁ.; Boronat Vitoria, T.; Balart Gimeno, RA. (2013). 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