2,367 research outputs found

    Beam test results of the irradiated Silicon Drift Detector for ALICE

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    The Silicon Drift Detectors will equip two of the six cylindrical layers of high precision position sensitive detectors in the ITS of the ALICE experiment at LHC. In this paper we report the beam test results of a SDD irradiated with 1 GeV electrons. The aim of this test was to verify the radiation tolerance of the device under an electron fluence equivalent to twice particle fluence expected during 10 years of ALICE operation.Comment: 6 pages,6 figures, to appear in the proceedings of International Workshop In high Multiplicity Environments (TIME'05), 3-7 October 2005, Zurich,Switzerlan

    Young consumers’ purchase behaviour of sustainably-labelled food products. What is the role of scepticism?

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    This paper aimed to investigate consumer scepticism towards third-party sustainability labels in the context of food products, evaluating its role in the formation of the customer’s buying behaviour. A covariance-based structural equation model (CB-SEM) was developed, and it included the customer’s socio-environmental concern, scepticism toward sustainability labels, reported use of the socio-environmental commitment declared by the producer, and purchase behaviour of sustainably-labelled food products. The model was tested on a sample of 311 Italian high-educated young consumers, a group of sustainability-conscious individuals. The findings highlight that purchase behaviour is positively influenced by two reciprocally-related variables: socio-environmental concern and the reported use of the socio-environmental commitment declared by the producer. While other studies have ascertained that scepticism is an antecedent of purchase behaviour, this study findings highlight it can also be considered a mediator of the relationships between purchase behaviour and other antecedents considered in this model. In addition to advancing the study on the role of scepticism in the formation of purchasing decisions for food products, drawing on signalling theory, this study provides insights for practitioners and policymakers, highlighting the absolute necessity to reassure consumers about the credibility of third-party sustainability labels and providing them with the instruments needed to distinguish the truth from the fluff in sustainability communication

    Making Virtue out of a Necessity: Women’s Entrepreneurial Motivation in Disadvantaged Areas. An Investigation Based on Generations

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    The study of entrepreneurial motivation has undergone a remarkable development in recent decades. Entrepreneurship scholars have shown a particular interest in understanding of the reasons that lead to entrepreneurial action in contexts characterised by considerable resource constraints. In relation to these contexts, many studies have drawn on push-pull theory to argue that necessity (push) or opportunity (pull) related motivations explain how entrepreneurial intention is formed. As part of the debate on entrepreneurial motivations in disadvantaged contexts and adopting a gender perspective, this paper aims to explore the motivations of women entrepreneurs leading young ventures. Their entrepreneurial action is not only subject to the vulnerabilities generally ascribed to young ventures and to the resource constraints of the territory in which they operate, but is also hampered by an additional obstacle in the form of gender roles, which involve behaviours not typically attributable to entrepreneurship. In particular, on the basis of a sample of 74 women entrepreneurs, we investigate the varying intensity of entrepreneurial motivations with reference to different groups definedon the basis of generations. For this purpose, a Multivariate Analysis of Variance (MANOVA) was carried out. The results showed that younger women entrepreneurs generally had higher values for the entrepreneurial motivations considered. Looking at individual items, significant differences were found in several cases, which can be traced to both necessity and opportunity motivations. Thus, we cannot claim that generational diversity alone implies a different intensity of necessity or opportunity motivations. Rather, we believe that younger women are generally more entrepreneurially motivated, and if well educated, they are able to proactively seek out opportunities, even if they decide to start a business out of necessity, as a way of escaping precarious work or the risk of having to emigrate from their home country

    A Cylindrical GEM Inner Tracker for the BESIII experiment at IHEP

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    The Beijing Electron Spectrometer III (BESIII) is a multipurpose detector that collects data provided by the collision in the Beijing Electron Positron Collider II (BEPCII), hosted at the Institute of High Energy Physics of Beijing. Since the beginning of its operation, BESIII has collected the world largest sample of J/{\psi} and {\psi}(2s). Due to the increase of the luminosity up to its nominal value of 10^33 cm-2 s-1 and aging effect, the MDC decreases its efficiency in the first layers up to 35% with respect to the value in 2014. Since BESIII has to take data up to 2022 with the chance to continue up to 2027, the Italian collaboration proposed to replace the inner part of the MDC with three independent layers of Cylindrical triple-GEM (CGEM). The CGEM-IT project will deploy several new features and innovation with respect the other current GEM based detector: the {\mu}TPC and analog readout, with time and charge measurements will allow to reach the 130 {\mu}m spatial resolution in 1 T magnetic field requested by the BESIII collaboration. In this proceeding, an update of the status of the project will be presented, with a particular focus on the results with planar and cylindrical prototypes with test beams data. These results are beyond the state of the art for GEM technology in magnetic field

    Theory of biopolymer stretching at high forces

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    We provide a unified theory for the high force elasticity of biopolymers solely in terms of the persistence length, ξp\xi_p, and the monomer spacing, aa. When the force f>\fh \sim k_BT\xi_p/a^2 the biopolymers behave as Freely Jointed Chains (FJCs) while in the range \fl \sim k_BT/\xi_p < f < \fh the Worm-like Chain (WLC) is a better model. We show that ξp\xi_p can be estimated from the force extension curve (FEC) at the extension x1/2x\approx 1/2 (normalized by the contour length of the biopolymer). After validating the theory using simulations, we provide a quantitative analysis of the FECs for a diverse set of biopolymers (dsDNA, ssRNA, ssDNA, polysaccharides, and unstructured PEVK domain of titin) for x1/2x \ge 1/2. The success of a specific polymer model (FJC or WLC) to describe the FEC of a given biopolymer is naturally explained by the theory. Only by probing the response of biopolymers over a wide range of forces can the ff-dependent elasticity be fully described.Comment: 20 pages, 4 figure

    A model to explain angular distributions of J/ψJ/\psi and ψ(2S)\psi(2S) decays into ΛΛ\Lambda\overline{\Lambda} and Σ0Σ0\Sigma^0\overline{\Sigma}^0

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    BESIII data show a particular angular distribution for the decay of the J/ψJ/\psi and ψ(2S)\psi(2S) mesons into the hyperons ΛΛ\Lambda\overline{\Lambda} and Σ0Σ0\Sigma^0\overline{\Sigma}^0. More in details the angular distribution of the decay ψ(2S)Σ0Σ0\psi(2S) \to \Sigma^0\overline{\Sigma}^0 exhibits an opposite trend with respect to that of the other three channels: J/ψΛΛJ/\psi \to \Lambda\overline{\Lambda}, J/ψΣ0Σ0J/\psi \to \Sigma^0\overline{\Sigma}^0 and ψ(2S)ΛΛ\psi(2S) \to \Lambda\overline{\Lambda}. We define a model to explain the origin of this phenomenon.Comment: 6 pages, 7 figures, to be published in Chinese Physics

    Measurement of proton electromagnetic form factors in e+eppˉe^+e^- \to p\bar{p} in the energy region 2.00-3.08 GeV

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    The process of e+eppˉe^+e^- \rightarrow p\bar{p} is studied at 22 center-of-mass energy points (s\sqrt{s}) from 2.00 to 3.08 GeV, exploiting 688.5~pb1^{-1} of data collected with the BESIII detector operating at the BEPCII collider. The Born cross section~(σppˉ\sigma_{p\bar{p}}) of e+eppˉe^+e^- \rightarrow p\bar{p} is measured with the energy-scan technique and it is found to be consistent with previously published data, but with much improved accuracy. In addition, the electromagnetic form-factor ratio (GE/GM|G_{E}/G_{M}|) and the value of the effective (Geff|G_{\rm{eff}}|), electric (GE|G_E|) and magnetic (GM|G_M|) form factors are measured by studying the helicity angle of the proton at 16 center-of-mass energy points. GE/GM|G_{E}/G_{M}| and GM|G_M| are determined with high accuracy, providing uncertainties comparable to data in the space-like region, and GE|G_E| is measured for the first time. We reach unprecedented accuracy, and precision results in the time-like region provide information to improve our understanding of the proton inner structure and to test theoretical models which depend on non-perturbative Quantum Chromodynamics

    Observation of the WW-Annihilation Decay Ds+ωπ+D^{+}_{s} \rightarrow \omega \pi^{+} and Evidence for Ds+ωK+D^{+}_{s} \rightarrow \omega K^{+}

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    We report on the observation of the WW-annihilation decay Ds+ωπ+D^{+}_{s} \rightarrow \omega \pi^{+} and the evidence for Ds+ωK+D_{s}^{+} \rightarrow \omega K^{+} with a data sample corresponding to an integrated luminosity of 3.19 fb1^{-1} collected with the BESIII detector at the center-of-mass energy s=4.178\sqrt{s} = 4.178 GeV. We obtain the branching fractions B(Ds+ωπ+)=(1.77±0.32stat.±0.11sys.)×103\mathcal{B}(D^{+}_{s} \rightarrow \omega \pi^{+}) = (1.77\pm0.32_{{\rm stat.}}\pm0.11_{{\rm sys.}}) \times 10^{-3} and B(Ds+ωK+)=(0.87±0.24stat.±0.07sys.)×103\mathcal{B}(D^{+}_{s} \rightarrow \omega K^{+}) = (0.87\pm0.24_{{\rm stat.}}\pm0.07_{{\rm sys.}}) \times 10^{-3}, respectively

    Amplified stretch of bottlebrush-coated DNA in nanofluidic channels

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    The effect of a cationic-neutral diblock polypeptide on the conformation of single DNA molecules confined in rectangular nanochannels is investigated with fluorescence microscopy. An enhanced stretch along the channel is observed with increased binding of the cationic block of the polypeptide to DNA. A maximum stretch of 85% of the contour length can be achieved inside a channel with a cross-sectional diameter of 200 nm and at a 2-fold excess of polypeptide with respect to DNA charge. With site-specific fluorescence labelling, it is demonstrated that this maximum stretch is sufficient to map large-scale genomic organization. Monte Carlo computer simulation shows that the amplification of the stretch inside the nanochannels is owing to an increase in bending rigidity and thickness of bottlebrush-coated DNA. The persistence lengths and widths deduced from the nanochannel data agree with what has been estimated from the analysis of atomic force microscopy images of dried complexes on silica.Singapore-MIT Alliance for Research and TechnologyNational Science Foundation (U.S.
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