999 research outputs found
Heavy Quark Fluorescence
Heavy hadrons containing heavy quarks (for example, Upsilon-mesons) feature a
scale separation between the heavy quark mass (about 4.5 GeV for the b-quark)
and the QCD scale (about 0.3 GeV}) that controls effective masses of lighter
constituents. Therefore, as in ordinary molecules, the de-excitation of the
lighter, faster degrees of freedom leaves the velocity distribution of the
heavy quarks unchanged, populating the available decay channels in
qualitatively predictable ways. Automatically an application of the
Franck-Condon principle of molecular physics explains several puzzling results
of Upsilon(5S) decays as measured by the Belle collaboration, such as the high
rate of Bs*-anti Bs* versus Bs*-anti Bs production, the strength of three-body
B-anti B + pion decays, or the dip in B momentum shown in these decays. We
argue that the data is showing the first Sturm-Liouville zero of the
Upsilon(5S) quantum mechanical squared wavefunction, and providing evidence for
a largely b-anti b composition of this meson.Comment: 4 pages, 4 figures, Figure 2 updated and some typos corrected. To be
published in Physical Review Letter
Solid-state memcapacitive system with negative and diverging capacitance
We suggest a possible realization of a solid-state memory capacitive
(memcapacitive) system. Our approach relies on the slow polarization rate of a
medium between plates of a regular capacitor. To achieve this goal, we consider
a multi-layer structure embedded in a capacitor. The multi-layer structure is
formed by metallic layers separated by an insulator so that non-linear
electronic transport (tunneling) between the layers can occur. The suggested
memcapacitor shows hysteretic charge-voltage and capacitance-voltage curves,
and both negative and diverging capacitance within certain ranges of the field.
This proposal can be easily realized experimentally, and indicates the
possibility of information storage in memcapacitive devices
subLiminal
The work explored in subLiminal deals heavily with color, emotion, amorphisms, and texture, which is meant to invoke discussions of tactility, functionality, and the place between personal and private sphere work, decorative and conceptual pieces, and ease versus disease. The room is filled with blobs and points of color, thought of as set design. The subLiminal room is in itself a suggestion, however, it is up to the audience what they wish to take away from it
Solid-State Memcapacitive System with Negative and Diverging Capacitance
We suggest a possible realization of a solid-state memory capacitive (memcapacitive) system. Our approach relies on the slow polarization rate of a medium between plates of a regular capacitor. To achieve this goal, we consider a multilayer structure embedded in a capacitor. The multilayer structure is formed by metallic layers separated by an insulator so that nonlinear electronic transport (tunneling) between the layers can occur. The suggested memcapacitor shows hysteretic charge-voltage and capacitance-voltage curves, and both negative and diverging capacitance within certain ranges of the field. This proposal can be easily realized experimentally and indicates the possibility of information storage in memcapacitive systems
Quasi-Fermi liquid behavior in a one-dimensional system of interacting spinless fermions
We present numerical evidence for a new paradigm in one-dimensional
interacting fermion systems, whose phenomenology has traits of both, Luttinger
liquids and Fermi liquids. This new state, dubbed a quasi-Fermi liquid,
possesses a discontinuity in its fermion occupation number at the Fermi
momentum. The excitation spectrum presents particle-like quasiparticles, and
absence of hole-like quasiparticles, giving rise instead to edge singularities.
Such a state is realized in a one-dimensional spinless fermion lattice
Hamiltonian by fine-tuning the interactions to a regime where they become
irrelevant in the renormalization group sense. We show, using uniform infinite
matrix products states and finite-entanglement scaling analysis, that the
system ground state is characterized by a Luttinger parameter and a
discontinuous jump in the fermion occupation number. We support the
characterization with calculations of the spectral function, that show a
particle-hole asymmetry reflected in the existence of well-defined Landau
quasiparticles above the Fermi level, and edge singularities without the
associated quasiparticles below. These results indicate that the quasi-Fermi
liquid paradigm can be realized beyond the low-energy perturbative realm.Comment: 9+3 pages; 8+4 figure
A Novel ARX-Based Approach for the Steady-State Identification Analysis of Industrial Depropanizer Column Datasets
This paper introduces a novel steady-state identification (SSI) method based on the auto-regressive model with exogenous inputs (ARX). This method allows the SSI with reduced tuning by analyzing the identifiability properties of the system. In particular, the singularity of the model matrices is used as an index for steady-state determination. In this contribution, the novel SSI method is compared to other available techniques, namely the F-like test, wavelet transform and a polynomial-based approach. These methods are implemented for SSI of three different case studies. In the first case, a simulated dataset is used for calibrating the output-based SSI methods. The second case corresponds to a literature nonlinear continuous stirred-tank reactor (CSTR) example running at different steady states in which the ARX-based approach is tuned with the available input-output data. Finally, an industrial case with real data of a depropanizer column from PETROBRAS S.A. considering different pieces of equipment is analyzed. The results for a reflux drum case indicate that the wavelet and the F-like test can satisfactorily detect the steady-state periods after careful tuning and when respecting their hypothesis, i.e., smooth data for the wavelet method and the presence of variance in the data for the F-like test. Through a heat exchanger case with different measurement frequencies, we demonstrate the advantages of using the ARX-based method over the other techniques, which include the aspect of online implementation
Predictors of unfavourable tuberculosis treatment outcome in Bilene District, Gaza Province, Mozambique: A retrospective analysis, 2016 - 2019
Background. Tuberculosis (TB) is a serious public health problem and remains one of the leading causes of death from an infectious agent globally. Mozambique is one of 30 countries considered to have a high TB burden.Objectives. To describe the clinical characteristics of TB in children and adults in Bilene District in Gaza Province, Mozambique, over 43 months and to assess determinants of unfavourable treatment outcomes.Methods. This retrospective cohort study took place from 1 January 2016 to 31 July 2019 in Bilene District, Gaza. We included patients in the TB register at the Centro de Saúde de Macia TB unit with available data on final treatment outcome. Predictors of unfavourable outcomes were determined using multivariable logistic regression models.Results. A total of 3 012 TB-infected patients were registered in the TB unit of the Macia health facility during the study period: 358 (11.9%) were children (<14 years), 1 522 (50.5%) were male, and 2 581 (85.7%) were new TB cases. No bacteriological test was performed at diagnosis in 1 250 patients (41.5%). Treatment was successful in 2 863 patients (95.1%), with better outcomes in children than in adults (98.0% v. 94.6%; p=0.005). Although mortality (n=97; 3.2%) was low in both groups, the proportion who died was lower in children compared with adults (1.4% v. 3.5%; p=0.035). Multivariable logistic regression analysis showed that unfavourable outcomes were more likely in men compared with women (adjusted odds ratio (aOR) 1.48; 95% confidence interval (CI) 1.04 - 2.12; p=0.029), in patients with recurrent TB infection compared with newly infected patients (aOR 1.63; 95% CI 1.05 - 2.50; p=0.027), and in patients co-infected with TB and HIV compared with HIV-negative TB-infected patients (aOR 2.17; 95% CI 1.43 - 3.29; p<0.001). The factor conferring the most risk for an unfavourable outcome was positive microbiological sputum results (aOR 5.27; 95% CI 3.25 - 8.54; p<0.001).Conclusions. Factors independently associated with an unfavourable TB treatment outcome were male sex, recurrent TB infection, having positive microbiology, and co-infection with HIV. It remains crucial to improve data quality and adherence to TB screening and diagnostic algorithms
- …