Miracle-dz/UniFAR-FTUs huggingface dataset:
Airflow and Precipitation Trajectories Within Severe Local Storms Which Travel to the Right of the Winds

Abstract A kinematic airflow model is proposed for severe local storms which travel to the right of the winds in the middle troposphere. The model is an extension of that proposed by Browning and Ludlam (1962), and represents an open system in which an updraft and a precipitation-maintained downdraft are fed persistently by air approaching the storm from its right flank. A qualitative consideration of precipitation trajectories enables the principal features of the radar structure of many severe local storms to be explained.
An assessment of mathematics teachers' Internet self-efficacy: implications on teachers' delivery of mathematics instruction

This study examined the mathematics teachers’ Internet self-efficacy and its possible influence on the delivery of mathematics instruction. The participants were 90 mathematics teachers selected from various schools in five local government areas of Osun State, Nigeria. The results demonstrated that to a great extent mathematics teachers have high Internet self-efficacy and that correlation exists between mathematics teachers’ age, Internet usage and Internet self-efficacy. Irrespective of gender, mathematics teachers have the same level of Internet self-efficacy. Moreover, Internet self-efficacy and usage were revealed to drastically improve the way teacher teach mathematics and conduct research. Upon these findings, it was recommended that mathematics teachers who do not know how to browse and search the Internet should consider doing so now without wasting much time. There is also the need to increase Internet usage, on the part of the mathematics teachers who just begin using the Internet. They need to do this considering the fact that increased usage leads to high Internet self-efficacy. Moreover, it is high time to close the technology gender gap which has been in existence since a long time. This can start from the mathematics teachers.
Elimination of impedance anomalies in single- and dual-polarized endfire tapered slot phased arrays

A method to eliminate bandwidth-limiting impedance anomalies or resonances in stripline-fed single- and dual-polarized tapered slot phased arrays is presented. For dual-polarized arrays, others have shown that the resonance with the lowest frequency is related to a cavity constituted by the dielectric region of the tapered slot element. Simulations have been performed to test if this cavity model also predicts the remaining resonances. It was found that the cavity model predicts some but not all of the resonances. However, it was found that all resonances in both single- and dual-polarized arrays have some dependence on the dielectric region. The resonances are effectively suppressed by introducing plated through vias in the element. The vias are positioned along the edges of the slotline, slotline cavity, stripline, and stripline stub. The analysis is performed with the finite-difference time-domain method by considering a unit cell in an infinite array.
Temporal modulation of plasma species in atmospheric dielectric barrier discharges

The atmospheric pressure dielectric barrier discharge in helium is a pulsed discharge in nature and the moment of maximum species densities is almost consistent with peak discharge current density. In this paper, a one-dimensional fluid model is used to investigate the temporal structure of plasma species in an atmospheric He-N2 dielectric barrier discharge (DBD). It is demonstrated that there exist microsecond delays of the moments of the maximum electron and ion densities from the peak of discharge current density. These time delays are caused by a competition between the electron impact and Penning ionizations, modulated by the N2 level in the plasma-forming gas. Besides, significant electron wall losses lead to the DBD being more positively charged and, with a distinct temporal separation in the peak electron and cation densities, the plasma is characterized with repetitive bursts of net positive charges. The temporal details of ionic and reactive plasma species may provide a new idea for some biologi.
Calibration of the Preston tube and limitations on its use in pressure gradients

Preston's method of measuring skin friction in the turbulent boundary layer makes use of a circular Pitot tube resting on the wall. On the assumption of a velocity distribution in the wall region common to boundary layer and pipe flows the calibration curve for the Pitot tube can be obtained in fully developed pipe flow. Earlier experiments suggested that Preston's original calibration was in error, and a revised calibration curve has been obtained and is presented here. From experiments in strong favourable and adverse pressure gradients, limits are assigned to the pressure-gradient conditions within which the calibration can be used with prescribed accuracy. It is shown that in sufficiently strong favourable gradients the ‘inner-law’ velocity distribution breaks down completely, and it is suggested that this breakdown is associated with reversion to laminar flow. As an incidental result, values have been obtained for the constants occurring in the logarithmic expression for the inner-law velocity distribution.
Topological solution of ordinary and partial finite difference equations

Using the discrete path formalism, we obtain a topological solution for ordinary, as well as partial, linear inhomogeneous finite difference equations with variable coefficients and arbitrarily specified boundary conditions. The solution is homomorphic to a set of discrete paths constructed from a set of vectors determined by the level differences of the equation.
The impact of sensor positioning on the array manifold

A framework is presented in this study which analyzes the importance of each sensor in an antenna array based on its location in the overall geometry. Moving away from the conventional methods of measuring sensor importance by means of application-specific criteria, a new approach, based on the array manifold and its differential geometry, is used to measure the significance of each sensor's position in an array. By considering two-dimensional manifolds (function of azimuth and elevation angles) of planar arrays of isotropic sensors, and by using previously established results on the differential geometry of such manifolds, a sensitivity analysis is performed which leads to characterization and quantification of sensor location importance in an array geometry. Based on this framework, a criterion is developed for assessing an overall geometry. This criterion may be used as a figure of merit for comparing diverse array geometries.
Two-dimensional electronic spectroscopy of an excitonically coupled dimer

The two-dimensional three-pulse photon echo signals from a dimer system are investigated in detail. A perturbative approach is used to calculate the response of the system via a numerical propagation of the density matrix in exciton state representation. Exciton vibrational coupling is modeled by Redfield relaxation theory. The main goal of this paper is to dissect the two-dimensional spectrum of the dimer to give better understanding of how the dynamics influence the spectral features. We will show how different Liouville pathways lead to the appearance/disappearance of diagonal and cross peaks. The inclusion of a Gaussian shaped electric field will be contrasted to the use of delta-pulses in the impulsive limit. The impulsive limit is found to be a satisfactory approximation at long population times, while at shorter times, in the pulse-overlap region, more realistic electric fields are called for.
Improved in vivo abdominal image quality using real-time estimation and correction of wavefront arrival time errors

The speed of sound varies with tissue type, yet commercial ultrasound imagers assume it is constant. Sound speed variation in abdominal fat and muscle layers is widely believed to be largely responsible for poor image contrast and resolution in some patients. The simplest model of the abdominal wall assumes that it adds a spatially varying time delay to the ultrasound wavefront. We describe an adaptive imaging system consisting of a GE LOGIQ 700 imager connected to a multi-processor computer. Arrival time errors for each beamforming channel, estimated by correlating each channel signal with the beamsum signal, are used to correct the imager's transmit and receive beamforming time delays at the image frame rate. A multi-row transducer provides two dimensional sampling of wavefront arrival time errors. After beamforming time delay correction, we observe significant improvement in abdominal images of healthy male volunteers, including increased contrast of blood vessels, increased brightness of liver tissue, and improved definition of the renal capsule and splenic boundary.
DWBA-G calculations of electron impact ionization of noble gas atoms

We perform calculations of electron impact ionization of noble gas atoms within the distorted wave Born approximation (DWBA) corrected by the Gamow factor (G) to account for the post-collision interaction. We make an extensive comparison with experimental data on He 1s2, Ne 2s2, 2p6 and Ar 3p6 under kinematics characterized by large energy transfer and close to minimum momentum transfer from the projectile to the target. For all atoms, good agreement between theory and experiment is achieved. In the case of Ar, the disagreement of experimental data with theory reported earlier by Catoire et al (2006 J. Phys. B: At. Mol. Opt. Phys. 39 2827) is reconciled.
The Effect of Computer-assisted Interviewing on Data Quality. A Review

Whether computer-assisted data collection methods should be used in social research is no longer an issue. Most professional research organisations, commercial, government and academic, are adopting these new methods with enthusiasm. Computer-assisted telephone interviewing (CATI) is most prevalent and computer-assisted personal interviewing (CAPI) is rapidly gaining in popularity. New interesting forms of computerised data collection, for instance automatic speech recognition, are also emerging. This raises the question of the influence of computer-assisted data collection methods on the quality of the data. In this article we review the literature on the topic, focusing mainly on the three basic forms of data collection in surveys: the face-to-face interview, the telephone interview, and the (mail) questionnaire. For a review of electronic observation techniques such as barcode scanning, or automatic registration of TV watching (people-or TV-meter) we refer to Saris (1989). For an interesting discussion on the potentials of people-meters that goes beyond mere registration and into full-fledged media research see Samuels (1994).
2-D/3-D multiply transmitted, converted and reflected arrivals in complex layered media with the modified shortest path method

SUMMARY Grid-cell based schemes for tracing seismic arrivals, such as the finite difference eikonal equation solver or the shortest path method (SPM), are conventionally confined to locating first arrivals only. However, later arrivals are numerous and sometimes of greater amplitude than the first arrivals, making them valuable information, with the potential to be used for precise earthquake location, high-resolution seismic tomography, real-time automatic onset picking and identification of multiple events on seismic exploration data. The purpose of this study is to introduce a modified SPM (MSPM) for tracking multiple arrivals comprising any kind of combination of transmissions, conversions and reflections in complex 2-D/3-D layered media. A practical approach known as the multistage scheme is incorporated into the MSPM to propagate seismic wave fronts from one interface (or subsurface structure for 3-D application) to the next. By treating each layer that the wave front enters as an independent computational domain, one obtains a transmitted and/or converted branch of later arrivals by reinitializing it in the adjacent layer, and a reflected and/or converted branch of later arrivals by reinitializing it in the incident layer. A simple local grid refinement scheme at the layer interface is used to maintain the same accuracy as in the one-stage MSPM application in tracing first arrivals. Benchmark tests against the multistage fast marching method are undertaken to assess the solution accuracy and the computational efficiency. Several examples are presented that demonstrate the viability of the multistage MSPM in highly complex layered media. Even in the presence of velocity variations, such as the Marmousi model, or interfaces exhibiting a relatively high curvature, later arrivals composed of any combination of the transmitted, converted and reflected events are tracked accurately. This is because the multistage MSPM retains the desirable properties of a single-stage MSPM: high computational efficiency and a high accuracy compared with the multistage FMM scheme.
Polarimetric performance of a Laue lens gamma-ray CdZnTe focal plane prototype

A gamma-ray telescope mission concept [gamma ray imager (GRI)] based on Laue focusing techniques has been proposed in reply to the European Space Agency call for mission ideas within the framework of the next decade planning (Cosmic Vision 2015-2025). In order to optimize the design of a focal plane for this satellite mission, a CdZnTe detector prototype has been tested at the European Synchrotron Radiation Facility under an similar to 100% polarized gamma-ray beam. The spectroscopic, imaging, and timing performances were studied and in particular its potential as a polarimeter was evaluated. Polarization has been recognized as being a very important observational parameter in high energy astrophysics (> 100 keV) and therefore this capability has been specifically included as part of the GRI mission proposal. The prototype detector tested was a 5 mm thick CdZnTe array with an 11 x 11 active pixel matrix (pixel area of 2.5 x 2.5 mm(2)). The detector was irradiated by a monochromatic linearly polarized beam with a spot diameter of about 0.5 mm over the energy range between 150 and 750 keV. Polarimetric Q factors of 0.35 and double event relative detection efficiency of 20% were obtained. Further measurements were performed with a copper Laue monochromator crystal placed between the beam and the detector prototype. In this configuration we have demonstrated that a polarized beam does not change its polarization level and direction after undergoing a small angle (< 1 degrees) Laue diffraction inside a crystal. (C) 2008 American Institute of Physics. [DOI:10.1063/1.3000092]
Experimental studies of air pocket movement in a pressurized spillway conduit

Undesired air entrainment in a bottom outlet conduit causes pressure transients, leading to conduit vibrations, blowbacks and discharge pulsations and thus endangers operational safety. In this study, the propagation velocity of a solitary air pocket and the characteristics of its critical velocity were examined in experiments conducted using a 240-mm-diameter pipe. Air pocket movement depends on the pipe diameter, slope, roughness and air pocket size. The critical pipe Froude number for initiating downstream movement of an air pocket is smaller in a larger pipe, most likely due to the scale effect and/or to a smaller reduction in the effective cross-sectional area. The critical velocity in rough pipes was found to be independent of the air pocket size. A minimum Froude number was suggested for a rough pipe instead of a critical pipe Froude number because the air removal process was found to involve successive air losses from the air pocket caused by turbulence.
Resolvent estimates on symmetric spaces of noncompact type

In this article we prove resolvent estimates for the Laplace- Beltrami operator or more general elliptic Fourier multipliers on symmetric spaces of noncompact type. Then the Kato theory implies time-global smoothing estimates for corresponding dispersive equations, especially the Schr¨odinger evolution equation. For low-frequency estimates, a pseudo- dimension appears as an upper bound of the order of elliptic Fourier multipliers. A key of the proof is to show a weighted L 2 -continuity of the modiﬁed Radon transform and fractional integral operators.
A MULTISCALE APPROACH TO CELL MIGRATION IN TISSUE NETWORKS

We derive a multiscale model for tumor cell migration allowing to account for the receptor-mediated movement of the cells, the degradation of tissue fibers and the subsequent production of a soluble ligand whose concentration gradient then acts together with the distribution of tissue fibers as a directional cue for the cells. For this model we present a result on the local existence and uniqueness of a solution in all biologically relevant space dimensions.
Quantification of trap state densities in GaAs heterostructures grown at varying rates using intensity-dependent time resolved photoluminescence

Time-resolved photoluminescence is an established technique for characterizing carrier lifetimes in semiconductors, but the dependence of lifetime on excitation fluence has been only qualitatively investigated. We develop a quantitative approach for fitting fluence-dependent PL decay data to a Shockely-Read-Hall model of carrier recombination in order to extract the trap state density. We demonstrate this approach by investigating growth rate-dependent trap densities in gallium arsenide-indium gallium phosphide double heterostructures. The techniques developed here can be applied for rapid, non-destructive quantification of trap state densities in a variety of materials.
Meteorological and Chemical Characteristics of the Photochemical Ozone Episodes Observed at Cape D’Aguilar in Hong Kong

As in many metropolitan areas around the world, air pollution in Hong Kong is an increasing concern. In this paper the authors present the observations of ozone (O 3) pollution episodes made at a nonurban coastal location in Hong Kong. Four O3 episodes were observed in 1994, during which hourly averaged O3 concentrations exceeded 100 ppbv and in one case reached 162 ppbv. Recirculation of urban air caused by the reversal of surface winds was found to be an important mechanism for transporting the ‘‘aged’’ urban plumes to the monitoring site. Concurrent measurements of CO, SO2, NO, and O3 provided an insight to the chemical characteristics of the air masses, and the chemical data appeared to suggest that the high levels of O 3 during the episodes were produced in the urban plumes that were mainly characteristic of vehicle emissions. The relationship between O3 and CO in two of the episodes may be represented by a linear approximation, and a nonlinear relationship between O3 and CO was found in another. Ozone levels observed at the nonurban site were higher than those at two urban locations.
Mechanisms controlling the onset of simulated convectively coupled Kelvin waves

Convectively coupled Kelvin waves (CCKW) are analysed using a cloud-resolving model to gain a better understanding of the mechanisms that initiate and drive these waves. We compare the modelled precipitation and vertical structure of a convectively coupled Kelvin wave to the mechanisms that control precipitation over warm tropical oceans: convective inhibition (CIN), saturation fraction, atmospheric stability and surface moist entropy fluxes. Our results show that the primary onset mechanism for precipitation associated with CCKW is CIN associated with a decrease in the threshold moist entropy. Saturation fraction and atmospheric instability exhibit a time lag in comparison with the rainfall evolution and are, therefore, not primary controls in the onset of these waves. The modelled CCKW evolve by starting with congestus convection, develop into deep convection and decay with the stratiform convection. The results from the presented model agree with observations and linearised models.
Association of Plant-Based and High-Protein Diets with a Lower Obesity Risk Defined by Fat Mass in Middle-Aged and Elderly Persons with a High Genetic Risk of Obesity

Obesity has become a severe public health challenge globally. The present study aimed to identify separate and interactive dietary, genetic, and other factors that increase the risk of obesity as measured by body fat (BF) mass. We utilized a genome-wide association study to identify genetic variants associated with high fat mass (obesity; n = 10,502) and combined them to generate polygenic risk scores (PRS) of genetic variants interacting with each other in adults aged over 40 while excluding body-fat-related diseases in a city-hospital-based cohort (n = 53,828). It was validated in Ansan/Ansung plus rural cohorts (n = 13,007). We then evaluated dietary and lifestyle factors in subjects to assess what factors might help overcome a genetic propensity for higher BF. The three-SNP model included brain-derived neurotrophic factor (BDNF)_rs6265, fat-mass- and obesity-associated protein (FTO)_rs1421085, and SEC16B_rs509325. The genes with the minor alleles of ADCY3_rs6545790 and BAIAP2_rs35867081 increased their gene expression in the visceral and subcutaneous adipocytes, but their gene expression decreased in the hypothalamus in eQTL analysis. In the three-SNP model, the PRS was associated with BF mass by 1.408 and 1.396 times after adjusting covariates 1 (age, gender, survey year, residence area, education, and income) and 2 (covariates in model 1 plus energy intake, alcohol intake, regular exercise, and smoking status), respectively. However, when separating subjects by PRS of the three-SNP model, a plant-based diet was the most significant factor associated with low BF, followed by high-protein diets and lower energy intakes. They could offset the effects of high genetic risk for high BF. In conclusion, modulating nutrient intakes might overcome a high genetic risk for obesity. Dietary choices favoring more plant-based and higher-protein foods might help prevent increased BF in Asians and potentially people of other ethnicities with high polygenetic risk scores.
Note on Fractional Powers of Linear Operators

In the preceding paper by K. Yosida, it is shown that the fractional power A, 0<a<l, of a linear operator A in a Banach space X can be constructed whenever--A is the infinitesimal generator of a strongly continuous, bounded semi-group {exp(--tA)}, and that--A also generates a semi-group {exp (--tA)} which has an analytic extension in a sector containing the positive t-axis. In the present paper we shall give another proof of these results, together with some generalizations. We consider linear operators in X which are not necessarily infinitesimal generators of semi-groups. For brevity we shall say that A is of type (o, M) if i) A is densely defined and closed, and ii) the resolvent set of --A contains the open sector arg 2]<n--o, 0<o< =, and 2(2+A)is uniformly bounded in each smaller sector arg 2 <--o--, > 0; in particular 1 2 [[ (2+A)][_<M, As is well known,--A is the infinitesimal generator of a strongly continuous contraction semi-group if and only if A is of type (/2, 1). Theorem 1. Let A be of type (w, M) with w<7/2. Then --A is the infinitesimal generator of a semi-group {Tt}t>o--[exp(--tA)} with the following properties.