Background Terms Research Articles

Analysis of the the $K^- p \to \gamma \Lambda$ reaction

Abstract In this work, we study the $K^- p \to \gamma \Lambda$ reaction in an effective Lagrangian approach and isobar model. Compared to previous studies using an Regge-plus-resonance model, here we consider the contributions of the $t$-channel($K$ and $K^*$) and $u$-channel(proton) exchanges explicitly as the background contribution. To restore the gauge invariance of the amplitude violated by introducing the phenomenological form factors, we employ two different methods that adopted in literatures. Then we discuss the roles of possible resonance contributions in this reaction and present the predictions of $\Lambda$ polarization based on various models. We find that the contribution of the background terms play an important role in the present reaction. On the other hand, the $\Lambda(1520)$, $\Sigma(1660)$ and $\Sigma(1670)$ resonances may also contribute in this reaction. Due to the uncertainties of the present data and the relatively small contributions of the hyperon resonances, we can not identify the roles of various hyperon resonances in the present work. While, we show that the measurement of the spin polarization of the final $\Lambda$ will be helpful to verify various models.

Prospects for detecting the hidden-strange pentaquarklike state N*(2080) in the π−p→ϕn reaction

In this work, the production of the hidden-strange pentaquarklike state, N*(2080), via the π−p scattering process is studied by the effective Lagrangian approach. Concretely, we consider the ρ meson exchange of t-channel and the nucleon exchange of u-channel, which are treated as the background terms, and take into account the contribution of the N*(2080) via the s-channel as a signal term. By global fitting of the total and differential cross sections of the π−p→ϕn process, it is shown that the N*(2080) contributes an obvious peak at the threshold energy point of the differential cross section at the forward angle (cosθ=1), which provides clues to the detection of the N*(2080) by the π−p scattering process. However, due to the limited accuracy of the experimental data, it is an objective limitation for us to determine the properties of the N*(2080) by the π−p scattering process. Therefore, more accurate experimental measurements of the π−p→ϕn reaction are highly desirable, and we have also proposed that correlation measurements can be performed on J-PARC, AMBER, and future HIKE and HIAF meson beam experiments. Published by the American Physical Society 2024

Isotropic Durgapal IV fluid sphere in bigravity

We analyze an isotropic uncharged fluid sphere model within bigravity considering the Durgapal IV metric (M.C. Durgapal, J. Phys. A: Math. Gen. 15, 2637 (1982)). In this work, we investigate the effects of the scale parameter k on the local matter distribution. Here, we have chosen the compact star candidate SMC X-1 with observed values of mass = (1.29 ± 0.05) M⊙ and radius [Formula: see text] km, respectively, to analyze our results analytically as well as graphically. For smaller values of k, we get the stiff (or hard) equation of state (EoS). Here, we solve the modified Einstein field equations in the presence of the background metric γμν. Due to this constant curvature background, the density and pressure terms are modified by adding an extra term, which affects the EoS. For r ≪ k, the background de Sitter space–time reduces into Minkowski form, and the coupling vanishes. We discuss certain physical quantities of our obtained solution, such as density, isotropic pressure, sound speed, pressure-density gradients, compactness, and surface redshift, to claim the physical viability of our model. It is found that our model clearly satisfies all the energy conditions, the causality condition, and the dynamical equilibrium via a modified Tolman–Oppenheimer–Volkov equation. Finally, we can conclude that our proposed model is physically realistic and well behaved.

Broadband THz Edge-Enhanced Imaging Technology Based on Electro-Optic Sampling

Based on the radial Hilbert transform of spatial filtering and electro-optical sampling, we propose a broadband terahertz edge-enhanced imaging method in this work. Instead of using a narrow-band THz vortex phase plate, here we use vortex ultrashort laser pulse to realize the THz enhancement imaging which can be applied for few-cycle THz imaging. The principle of edge enhancement is analyzed theoretically, and the analytical expression of the final terahertz imaging is derived. We found that edge-enhancement imaging corresponds to the nonlinear term of the THz field, and the background and linear terms can be suppressed when the static birefringent phase is set to zero. The simulations show that our method can effectively improve the contrast and signal-to-noise ratio of terahertz imaging.

Shaping the Knowledge Base of Bioeconomy Sectors Development in Latin American and Caribbean Countries: A Bibliometric Analysis

Academic research on bioeconomy sectors in Latin American and Caribbean countries has developed exponentially over the last few years. Based on the Web of Science (WOS) database and statistical analysis of more than 18.9 thousand documents, the current article offers a bibliometric analysis of these datasets. The main bioeconomy sector identified in the results was biofuel production and all the background terms related to the primary processes of bioenergy. The other segments of the bioeconomy in the Latin America and Caribbean (LAC) region have not yet been studied with the same relevance as biofuels. Since 2008, researchers from Latin American and Caribbean countries have participated significantly in the scientific production of the field studied. However, the most relevant scientific journals belong to European countries or the United States. Journals from Latin American and Caribbean countries have very low representation, although the search topics are directly related to this region. Based on the co-occurrence of keywords, eight clusters with different levels of importance can be distinguished: (1) agriculture; (2) climate change; (3) biodiversity; (4) bioremediation; (5) bioenergy; (6) biofuels; (7) energy efficiency; and (8) bioeconomy. The above results highlight the significant research gap between biofuels and other types of bioeconomy sectors in the region. This is despite the immense biodiversity potential of the LAC countries, which can generate innovative products with bioeconomic added value that can stimulate scientific research in the sustainable bioeconomy.

The π−p→a0−ηp reaction in an effective Lagrangian model

In this work, we perform a study of the ${\ensuremath{\pi}}^{\ensuremath{-}}p\ensuremath{\rightarrow}{a}_{0}^{\ensuremath{-}}\ensuremath{\eta}p$ reaction within an effective Lagrangian approach and isobar model. In our model, we consider the excitation of the ${N}^{*}$ and ${\mathrm{\ensuremath{\Delta}}}^{*}$ resonances in the intermediate states and background terms. Based on our model, it is found that this reaction is dominated by the production of the $N(1535)$ in the near threshold region. And the contributions from other well-established ${N}^{*}$ or ${\mathrm{\ensuremath{\Delta}}}^{*}$ resonances only play minor roles. Besides, we discuss the possibility of verifying the existence of a narrow nucleon resonance $N(1685)$/$N(1700)$ proposed by some recent works in the present reaction. With adopting different quantum numbers, we find that it may contribute significantly in this reaction. Thus this reaction may provide a good platform to study the properties of nucleon resonances, e.g., $N(1535)$ and $N(1685)$/$N(1700)$, which couple strongly with the $\ensuremath{\eta}N$ channel. To compare with future experiments, the predictions of the total cross sections, the angular distributions, and invariant mass spectrums of final particles are also presented. Furthermore, the off-shell effects due to high-spin states are also discussed.

Charged current neutrino and antineutrino induced eta production off the nucleon

The charged current (anti)neutrino induced eta production from the nucleons is studied in a model based on the effective Lagrangians to evaluate the contribution from the nonresonant and resonant diagrams. The contribution from the nonresonant background terms has been obtained using a microscopic model based on the SU(3) chiral Lagrangians. The contribution from the resonant diagrams due to the low lying ${S}_{11}(1535)$, ${S}_{11}(1650)$, and ${P}_{11}(1710)$ resonances has been evaluated using an effective phenomenological Lagrangian with its parameters determined from the experimental values of their branching ratios and decay widths to the $N\ensuremath{\eta}$ channel. The model is first used to reproduce satisfactorily the experimental data from the MAINZ and JLab on the total cross sections for the photo- and electro- production of $\ensuremath{\eta}$ mesons, which fixes the model parameters in the vector current interaction. The partially conserved axial vector current (PCAC) hypothesis and generalized Goldberger-Treiman relation are used to fix the parameters of the axial vector current interaction. The model is then applied to study the weak production of eta mesons induced by the neutrinos and antineutrinos, and predicts the numerical values for the ${Q}^{2}$-distribution, $\ensuremath{\eta}$-momentum distribution, and the total cross section for the reactions ${\ensuremath{\nu}}_{\ensuremath{\mu}}+n\ensuremath{\rightarrow}{\ensuremath{\mu}}^{\ensuremath{-}}+p+\ensuremath{\eta}$ and ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}+p\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}+n+\ensuremath{\eta}$ in the energy region up to 2 GeV. It is found that the photo, electro, and (anti)neutrino induced production of eta mesons is dominated by the contribution from the ${S}_{11}(1535)$ resonance. The results discussed in this work are relevant for the present and future accelerator experiments like MicroBooNE, T2K, NOvA, MINERvA, T2-HyperK, and DUNE as well as for the atmospheric neutrino experiments.

Automated Analysis of Reflection Mode Terahertz Hyperspectral Images

A suite of algorithms and associated procedures, originally developed for mineral exploration applications, are adapted for application to terahertz hyperspectral images measured in reflection mode. Such data are often quite noisy due to the low reflectivity of many materials at terahertz frequencies. The algorithms and procedures are based on an extended linear mixture model consisting of two parts. The first part, called the “foreground”, models the distinguishing parts of the spectra of materials (including mixtures) of interest (especially their diagnostic absorption features). The second part, called the “background”, models parts of the spectra that are typically of lesser interest, such as variation in low frequencies and water vapor. The model and procedures are exemplified with a spectral library of six materials and are applied to three hyperspectral images, one consisting only of pure pellets, some of which are not in the library, and two of which contain both pure and mixed pellets of three of the materials in the library. The associated procedures include the following: estimating the number of materials in the mixture at each pixel; identifying pixels with materials that are well modeled by the background terms only; identifying pixels with materials not in the library; and identifying pixels containing metal. Finally, this article concludes with a discussion of some outstanding issues.

Dynamical Majorana neutrino masses and axions II: Inclusion of anomaly terms and axial background

We extend the study of a previous publication [1] on Schwinger-Dyson dynamical mass generation for fermions and pseudoscalar fields (axion-like particles (ALP)), in field theories containing Yukawa type interactions between the fermions and ALPs, by incorporating anomaly terms and/or (constant) axial background fields. The latter are linked to some Lorentz-(and CPT-)violating scenarios for leptogenesis in the early Universe. We discuss both Hermitian and non-Hermitian Yukawa interactions and axial backgrounds, which are motivated in the context of some scenarios for radiative (anomalous) Majorana sterile neutrino masses in some effective field theories, including attractive four-fermion interactions. The reality requirement for the radiative, anomalously generated, mass component for the fermions, restricts our considerations to the cases where Yukawa interactions and the anomaly terms are either both Hermitian or both anti-Hermitian. We show that, for a Hermitian Yukawa interaction, there is no (pseudo)scalar dynamical mass generation, but there is fermion dynamical mass generation, provided one adds a bare (pseudo)scalar mass. For this case, the Hermitian anomaly terms play a similar rôle in inducing dynamical mass generation for fermions as the four-fermion attractive interactions, and as such they can themselves generate a small dynamical mass. For anti-Hermitian Yukawa interactions, an anti-Hermitian anomaly resists mass generation. The axial background terms assist dynamical mass generation induced by anti-Hermitian Yukawa interactions, in the sense that the larger the magnitude of the background, the larger the dynamical mass. For Hermitian Yukawa interactions, however, the situation is the opposite, in the sense that the larger the background the smaller the dynamical mass. We also compare the anomaly-induced dynamical mass with the radiative fermion mass in models of sterile neutrinos, and find that in cases where the dynamical mass occurs, the latter dominates over the anomalously generated radiative sterile-neutrino mass.

Learning to Build Accurate Service Representations and Visualization

With the boom of Web services, there is a growing need for visualizing service ecosystems to help people browse services and understand their functionalities and positions in the systems. One foundational step of building a proper visualization is to ensure accurate representations for the comprising services. However, it is not a trivial task as service profiles may not be sufficient for two significant reasons. First, while the services themselves being used in various scenarios, their profiles may not always precisely reflect all of them. Second, service profiles usually comprise quite a few universal background terms that cannot distinguish services. To address these two issues, we apply machine learning techniques to incrementally learn service representations in a whole. A tailored topic model is developed, named Service Representation-Latent Dirichlet Allocation (SR-LDA). The core idea is to learn more comprehensive and up-to-date information about services from the profiles of the involved service compositions (i.e., mashup profiles), while introducing a global filter to identify and filter out background terms. Both quantitative and qualitative experiments on a real-world dataset demonstrate that the proposed SR-LDA builds higher-quality service representations comparing with baselines. We further generate a knowledge map to visualize a service ecosystem based on the learned service representations. Such a knowledge map directly leads to the detection of four typical functionality patterns of Web services and serves the purpose of mashup creation.

Worker's Compensation Terminology.

Injuries to the spine comprise a high percentage of workplace injuries. Spine surgeons' evaluation of injured workers requires attention to facts specific to worker's compensation claims including whether the injury occurred in the scope of employment, whether a work incident was causally related to the injury, and whether the injury contributed to a significant degree to the patient's overall medical condition. An injured worker's compensation is subject to state-specific guidelines and is largely dependent on the degree of disability and whether the disability is temporary or permanent. Here, we review the background, organization, and key terms used in the worker's compensation system.

The Use of Descriptive Terms for Ventricular Size on Noncontrast Head CT Radiology Reports

Background and PurposeMultiple radiographic terms can be used to describe enlarged ventricles on noncontrast head computed tomography (CTs); however, precise terminology is important to determine etiology and clinical management. The purpose of this study was to characterize how ventricular size was described in radiology reports, especially in the setting of hydrocephalus. Materials and MethodsA retrospective review of adult patients with at least 2 consecutive noncontrast head CTs from 2010 to 2016 was performed. Reports were grouped based on ventricular descriptions into 3 categories: “acceptable,” “unclear,” and “not acceptable.” An additional subgroup was created for an examination indication of “hydrocephalus.” Descriptive statistics and subgroup analysis were performed. ResultsA total of 270 patients with noncontrast head CTs were included, of which 53.3% (n = 144) used “acceptable” terms, 18.2% (n = 49) “unclear,” and 28.5% (n = 77) “not acceptable.” Ventricle size was reported as normal in 21.1% (n = 57) of cases. “Hydrocephalus” was given as an indication for 57 exams, of which 84.2% (n = 48) were categorized as “acceptable,” 7.0% (n = 4) “unclear,” and 8.8% (n = 5) “not acceptable.” Chi-square test of independence revealed a significant relation between “acceptable” terminology and “hydrocephalus” indication (χ2 = 27.68, P< 0.001). ConclusionApproximately half of radiology reports had an “acceptable” description of the ventricles. When “hydrocephalus” was in the indication, the report was more likely to have an “acceptable” description. Accurate clinical indications, and standardized terminology may improve the clinical utility of radiology reports for patients with hydrocephalus.

Optical resonance scattering of a dielectric sphere of arbitrary size illuminated by polarized Airy beams

The optical resonance scattering of a dielectric sphere of arbitrary size illuminated by a polarized Airy beam is studied using the generalized Lorenz–Mie theory (GLMT). The electric field is derived using the vector angular spectrum decomposition method (VASDM). The beam shape coefficients (BSCs) are obtained using the multipole expansion method involving vector spherical wave functions (VSWFs). The resonance scattering characteristics are calculated using the GLMT by subtracting a non-resonant background of a perfectly conducting impenetrable sphere. The effects of beam polarization (i.e., linear, circular, radial, azimuthal, and mixed), the attenuation parameter γ and the dimensionless transverse scale kω0 of the incident Airy beam on the scattering and extinction, “resonance” and “interference” efficiencies are examined. Moreover, the scattering efficiency for a perfectly conducting sphere as well as the three-dimensional (3D) scattering directivity patterns of the normalized dimensionless far-field scattering intensity and its resonance counterpart are calculated and plotted. The analysis of the resonance scattering shows that the energy efficiency is not the mere sum of resonance and perfectly conducting background terms; there is an interference between the two denoted by Qscainterf, which strongly affects the resonance extinction and scattering efficiencies. The results presented here are of some importance in studying the optical resonance scattering of polarized Airy beams in applications involving imaging, particle sizing, radiation forces and torques to name a few areas of research.

Outcomes Standardisation Project (OSP) for Continuing Medical Education (CE/CME) Professionals: Background, Methods, and Initial Terms and Definitions

ABSTRACT Despite an increased focus and urgency for CE/CME professionals to effectively and systematically assess the impact of their educational interventions, the community has struggled to do so. This struggle is in large part due to the lack of a standardised outcomes language and a set of unified approaches to measure and communicate impact. In the spring of 2018, a group of volunteer educational research scientists and CE/CME professionals established a rigorous consensus-building process in an effort to address this need. This report describes the background, methods and first-year output (Glossary V1) of the Outcomes Standardisation Project (OSP); begins to introduce examples of how the OSP Glossary V1 may support the CE/CME professional community and concludes with plans for the future of establishing a common framework for the profession.

Model-independent method for measuring the angular coefficients of B0→ D∗−τ+ντ decays

Reconstruction of the B0→ D∗−τ+ντ angular distribution is complicated by the strongly biasing effect of losing the neutrino information from both the B and τ decays. In this work, a novel method for making unbiased measurements of the angular coefficients while preserving the model independence of the angular technique is demonstrated. The twelve angular functions that describe the signal decay, in addition to background terms, are modelled in a multidimensional fit, using template probability density functions that encapsulate all resolution and acceptance effects. Sensitivities at the LHCb and Belle II experiments are estimated, and sources of systematic uncertainty are discussed, notably in the extrapolation to a measurement of R(D∗).

Partial wave analysis for KΣ photoproduction on the nucleon valid from threshold up to W = 2.8 GeV

We have simultaneously analyzed the available kaon photoproduction data for the , , , and channels by using an isobar model constructed from the Feynman diagrammatic approach for the background terms and multipoles formulation for the resonance terms. The unknown coupling constants in the background terms as well as the helicity amplitudes and the kaon branching ratios of the resonance terms were extracted by fitting the calculated observables to nearly 8000 data points from the latest experimental measurements, including the recent and data from MAMI A2 collaboration. During the fitting process we used the data listed in the Review of Particle Properties of Particle Data Group as a guidance for the resonance properties. Since in the previous study the kaon branching ratio of the N(1710)P11 state was found to be relatively large and, as a consequence, a sizable spike appeared in the K+Σ− cross section near the threshold, in the present work we propose two isobar models, i.e. with and without this state. We have found that both models can nicely fit the data. Extensive comparisons between the result of model calculation and experimental data are presented in this paper. To investigate the role of each resonance in the present work the significance of each resonance is calculated and discussed. The present work indicates that the N(1895)S11 and Δ(1900)S31 as the important resonances in the KΣ photoproduction. We also present two examples of application of the presented isobar models, i.e. investigation of the nucleon resonance N(1535)S11 coupling to the KΣ channels and the contribution of KΣ channels to the Gerasimov–Drell–Hearn sum rule.

Automatized fringe pattern preprocessing using unsupervised variational image decomposition.

Successful single-frame fringe pattern preprocessing comprising high-frequency noise minimization and low-frequency background removal represents often the crucial step of the fringe pattern based full-field optical metrology (i.e., interferometry, moiré, structured light). It directly determines the measurement accuracy. Data-driven decomposition by means of the 2D empirical mode decomposition (EMD) serves the filtering purpose in adaptive and detail-preserving manner. The mode-mixing phenomenon resulting in troublesome automatic grouping of modes into three main fringe pattern components (background, information part and noise) is significantly limiting this process, however. In this paper we are introducing the unsupervised variational image decomposition (uVID) model especially tailored to overcome this preprocessing problem and assure successful sparse three-component fringe pattern decomposition. Comprehensive analysis and detailed studies of accomplished significant advancements ensuring automation, versatility and robustness of the proposed approach are provided. Main advancements include: (1) tailoring the VID calculation scheme to fringe pattern preprocessing purpose by focusing onto accurate fringe extraction with tolerance parameter and custom-made decomposition parameter values; (2) fringe pattern tailored BM3D denoising algorithm with fixed parameter values. Numerical and experimental investigations corroborate that the demonstrated uVID method compares favorably with the reference 2D EMD algorithm and classical VID model. Remarkable range of acceptable local variations of the fringe pattern orientation, period, noise, contrast and background terms is to be highlighted.

A conceptual model and empirical assessment of HR security risk management

PurposeThis study aims to develop a conceptual model and assess the extent to which pre-, during- and post-employment HR security controls are applied in organizations to manage information security risks.Design/methodology/approachThe conceptual model is developed based on the agency theory and the review of theoretical, empirical and practitioner literature. Following, empirical data are collected through a survey from 134 IT professionals, internal audit personnel and HR managers working within five major industry sectors in a developing country to test the organizational differences in pre-, during- and post-employment HR security measures.FindingsUsing analysis of variance, the findings reveal significant differences among the organizations. Financial institutions perform better in employee background checks, terms and conditions of employment, management responsibilities, security education, training and awareness and disciplinary process. Conversely, healthcare institutions outperform other organizations in post-employment security management. The government public institutions perform the worst among all the organizations.Originality/valueAn integration of a conceptual model with HR security controls is an area that is under-researched and under-reported in information security and human resource management literature. Accordingly, this research on HR security management contributes to reducing such a gap and adds to the existing HR security risk management literature. It, thereby, provides an opportunity for researchers to conduct comparative studies between developed and developing nations or to benchmark a specific organization’s HR security management.

Addendum to predicting the $K^0\Lambda$ photoproduction observables by using the multipoles approach

Abstract We present an addendum to our previous paper to improve the performance of the proposed isobar model in describing the $\gamma + n\to K^0+\Lambda$ reaction observables. Since two new data sets have become available for this reaction channel that show sizable discrepancies, i.e. the CLAS and MAMI data, we propose three different models, M1, M2, and M3, obtained from including the CLAS, MAMI, and both data sets, respectively, in the fitting database. The new models can nicely describe the $\gamma+p\to K^++\Lambda$ observables, as in the case of the previous model, but significantly improve the agreement with the new $\gamma + n\to K^0+\Lambda$ cross section data. The extracted resonance properties in the present models can be well constrained within the current Particle Data Group estimates. The different contributions of the background and resonance terms in the previous and present calculations are thoroughly discussed. A brief discussion on the problem of data discrepancy is also presented.

Artifact Handling Based on Depth Image for View Synthesis

The depth image based rendering (DIBR) is a popular technology for 3D video and free viewpoint video (FVV) synthesis, by which numerous virtual views can be generated from a single reference view and its depth image. However, some artifacts are produced in the DIBR process and reduce the visual quality of virtual view. Due to the diversity of artifacts, effectively handling them becomes a challenging task. In this paper, an artifact handling method based on depth image is proposed. The reference image and its depth image are extended to fill the holes that belong to the out-of-field regions. A depth image preprocessing method is applied to project the ghosts to their correct place. The 3D warping process is optimized by an adaptive one-to-four method to deal with the cracks and pixel overlapping. For disocclusions, we calculate depth and background terms of the filling priority based on depth information. The search for the best matching patch is performed simultaneously in the reference image and the virtual image. Moreover, adaptive patch size is used in all hole-filling processes. Experimental results demonstrate the effectiveness of the proposed method, which has better performance compared with previous methods in subjective and objective evaluation.