8,781 research outputs found

    Signatures of fractional Hall quasiparticles in moments of current through an antidot

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    The statistics of tunneling current in a fractional quantum Hall sample with an antidot is studied in the chiral Luttinger liquid picture of edge states. A comparison between Fano factor and skewness is proposed in order to clearly distinguish the charge of the carriers in both the thermal and the shot limit. In addition, we address effects on current moments of non-universal exponents in single-quasiparticle propagators. Positive correlations, result of propagators behaviour, are obtained in the shot noise limit of the Fano factor, and possible experimental consequences are outlined

    BĂĽchwald-Hartwig reaction applied to synthesis of new luminescent liquid crystal triarylamines derived from isoxazoles

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    © 2015 Taylor & Francis Group, LLC. The present work describes the synthesis and characterization of novel series of triarylamines isoxazoles (TAA) addressed to the organic photovoltaic materials. Diarylisoxazoles were synthesized by sequential [3+2] 1,3-dipolar cycloaddition reaction between arylnitrile oxides and selected arylalkenes followed by MnO2-oxidation. Isoxazoles were coupled to diarylamines by Büchwald-Hartwig reaction to afford desired compounds 6a-k. Some TAA display liquid-crystalline behaviour and UV-Vis absorption and fluorescence emission were analysed for all samples of TAA 6a-k

    PI3Kinase signaling in glioblastoma

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    Glioblastoma (GBM) is the most common primary tumor of the CNS in the adult. It is characterized by exponential growth and diffuse invasiveness. Among many different genetic alterations in GBM, e.g., mutations of PTEN, EGFR, p16/p19 and p53 and their impact on aberrant signaling have been thoroughly characterized. A major barrier to develop a common therapeutic strategy is founded on the fact that each tumor has its individual genetic fingerprint. Nonetheless, the PI3K pathway may represent a common therapeutic target to most GBM due to its central position in the signaling cascade affecting proliferation, apoptosis and migration. The read-out of blocking PI3K alone or in combination with other cancer pathways should mainly focus, besides the cytostatic effect, on cell death induction since sublethal damage may induce selection of more malignant clones. Targeting more than one pathway instead of a single agent approach may be more promising to kill GBM cell

    Analysis of General Power Counting Rules in Effective Field Theory

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    We derive the general counting rules for a quantum effective field theory (EFT) in d\mathsf{d} dimensions. The rules are valid for strongly and weakly coupled theories, and predict that all kinetic energy terms are canonically normalized. They determine the energy dependence of scattering cross sections in the range of validity of the EFT expansion. We show that the size of cross sections is controlled by the Λ\Lambda power counting of EFT, not by chiral counting, even for chiral perturbation theory (χ\chiPT). The relation between Λ\Lambda and ff is generalized to d\mathsf{d} dimensions. We show that the naive dimensional analysis 4π4\pi counting is related to ℏ\hbar counting. The EFT counting rules are applied to χ\chiPT, low-energy weak interactions, Standard Model EFT and the non-trivial case of Higgs EFT.Comment: V2: more details and examples added; version published in journal. 17 pages, 4 figures, 2 table

    Relevance of multiple-quasiparticle tunneling between edge states at \nu =p/(2np+1)

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    We present an explanation for the anomalous behavior in tunneling conductance and noise through a point contact between edge states in the Jain series ν=p/(2np+1)\nu=p/(2np+1), for extremely weak-backscattering and low temperatures [Y.C. Chung, M. Heiblum, and V. Umansky, Phys. Rev. Lett. {\bf{91}}, 216804 (2003)]. We consider edge states with neutral modes propagating at finite velocity, and we show that the activation of their dynamics causes the unexpected change in the temperature power-law of the conductance. Even more importantly, we demonstrate that multiple-quasiparticles tunneling at low energies becomes the most relevant process. This result will be used to explain the experimental data on current noise where tunneling particles have a charge that can reach pp times the single quasiparticle charge. In this paper we analyze the conductance and the shot noise to substantiate quantitatively the proposed scenario.Comment: 4 pages, 2 figure

    Hybrid Superconducting Neutron Detectors

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    A new neutron detection concept is presented that is based on superconductive niobium (Nb) strips coated by a boron (B) layer. The working principle of the detector relies on the nuclear reaction 10B+n →\rightarrow α\alpha+ 7Li , with α\alpha and Li ions generating a hot spot on the current-biased Nb strip which in turn induces a superconducting-normal state transition. The latter is recognized as a voltage signal which is the evidence of the incident neutron. The above described detection principle has been experimentally assessed and verified by irradiating the samples with a pulsed neutron beam at the ISIS spallation neutron source (UK). It is found that the boron coated superconducting strips, kept at a temperature T = 8 K and current-biased below the critical current Ic, are driven into the normal state upon thermal neutron irradiation. As a result of the transition, voltage pulses in excess of 40 mV are measured while the bias current can be properly modulated to bring the strip back to the superconducting state, thus resetting the detector. Measurements on the counting rate of the device are presented and the future perspectives leading to neutron detectors with unprecedented spatial resolutions and efficiency are highlighted.Comment: 8 pages 6 figure

    Precision medicine in heart failure no longer a visual theory but a realistic opportunity

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    Over the last decades, major advances in the understanding of pathophysiology in a wide spectrum of cardiovascular diseases provided several effective pharmacological and non-pharmacological therapies [1]. Along with novel rehabilitation and follow up strategies, these advances have improved the survival rate of cardiac diseases, globally, and contributed generally to a significant increase in life expectancy [2]. As a consequence, there is a parallel increase of patients suffering from challenging and multifaceted syndromes such as heart failure (HF). HF is a recognised pandemic disease, with a progressively increasing prevalence in the aging population [3]. It is a major public health issue, considering both its social and economic implications. HF patients are characterised by a high level of complexity because of the advanced age and the presence of multiple relevant comorbidities requiring dedicated polytherapy [1]. Therefore, overall mortality of HF patients is still unacceptably high, exceeding that of several neoplasms, carrying a risk of approximately 10% at 12 months from clinical onset [4]

    Le Archeidi di Giulio Turcato problematiche conservative e proposte di intervento

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    Le Archeidi, gruppo scultoreo composto da cinque elementi realizzati con laminati di ferro a struttura tubolare assemblati artigianalmente, sono alte circa quattro metri e il loro ingombro varia tra gli ottanta e i novanta centimetri. Vennero realizzate da Giulio Turcato nel 1989 per la citt\ue0 di Salerno, in occasione della prima edizione di \u201cSalerno Incontri d\u2019Arte\u201d, parallelamente alla mostra \u201cGiulio Turcato per/Corso\u201d, tenutasi in tre gallerie della citt\ue0 \u201cLa Bottegaccia\u201d, \u201cIl Catalogo\u201d e \u201cLa Seggiola\u201d. Il gruppo scultoreo era composto da quattro elementi che erano stati scherzosamente definiti dal maestro \u201caculei\u201d e da un quinto che ricordava le sembianze di un \u201cfiore\u201d. Purtroppo, appena le opere vennero collocate lungo il percorso cittadino, una sub\uec un atto vandalico mentre un\u2019altra venne trafugata. Le cinque sculture furono realizzate, seguendo il progetto dell\u2019artista, nella bottega di un fabbro salernitano e successivamente trattate cromaticamente. Le ragioni principali del degrado delle Archeidi sono legate alla collocazione in ambiente esterno e al fatto che l\u2019aspettativa di vita dei materiali utilizzati non garantisce la durabilit\ue0 del gruppo scultoreo. Quattro strutture, di propriet\ue0 del Comune di Salerno, si presentano oggi in un precario stato di conservazione, aggravato dall\u2019umidit\ue0 dello spazio dove sono conservate. Ad un\u2019osservazione preliminare si riscontra un viraggio completo dei colori e la presenza diffusa di ruggine. Le opere, dopo un accurato intervento di restauro, attendono di trovare una nuova collocazione che risponda alle necessit\ue0 di una buona conservazione e al tempo stesso alla natura di \u201copera ambientale\u201d cos\uec come ideata dall\u2019artista
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