bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computation of HF Ground Backscatter Amplitude
Authors: Croft Thomas A. 
Published: November 2015

An HF backscatter radar system is simulated by a digital computer method which includes the detailed influence of the ionosphere through use of precomputed rays. To insure a fairly realistic simulation, allowance is made for the following factors: a spherical earth and ionosphere, electron density variations with height and range, absorption which varies with range and ray angle, antenna gain as a function of azimuth and elevation, ground scattering and specular reflection characteristics which vary with range and angle of incidence, and the transmitted pulse shape. The main approximations are (a) that ray theory is used with the assumption that most energy is distributed uniformly between closely spaced ray paths, and (b) that the effect of the geomagnetic field on ray‐path range and transit time is neglected.This computer simulation has two main applications. First, it permits the study of idealized backscatter problems by controlled variation of one parameter at a time. For example, a localized irregularity may be inserted in the ionosphere and the backscatter can be calculated with and without it. Second, it is possible to match experimental backscatter with synthetic backscatter for the purpose of evaluating the ground‐scatter coefficient or estimating the existing ionospheric structure. This process requires carefully calibrated experimental data because the comparison must be quantitative. Some early results of this work are shown.
Scattering of Electromagnetic Waves From a Slightly Rough Surface Moving With Uniform Velocity
Authors: Valenzuela G. R. 
Published: November 2015

The scattering of electromagnetic waves from a slightly rough surface moving with uniform velocity is investigated.Rice's generalization of Rayleigh's expansion for the scattered fields and Lorentz transformation are used to relate the fields in the moving and stationary reference frames. In the development we also use the principle of phase in variance and the covariance nature of the electromagnetic fields.
Signal and Noise Characteristics in Radiometric Correlation Detectors
Authors: Joseph Buck G. 
Published: November 2015

In radio astronomy and other radiometric applications, correlation antenna‐receiver systems are used to measure the Fourier transform of the far‐field temperature distribution. In this paper, the effect of a finite observation bandwidth upon the measurement of the transform is determined.The noise components in the output of the correlator‐antenna system which is observing a distributed source are calculated. The noise power present in the measurement of the real component of the Fourier transform is found to depend on the square of the sum of the integrated temperature distribution and the receiver noise, also upon the square of the real part of the Fourier transform, and the negative of the square of the imaginary part of the Fourier transform. Similar results with appropriate sign changes apply to the imaginary portion of the Fourier transform. The practical restriction on the allowable bandwidth of the correlation receiver is also apparent in these calculations.These values of the signal and noise power can then be used for the optimum processing of the received signal.
Characteristics of Auroral Brightness Fluctuations
Authors: Shepherd G. G. , Pemberton E. V. 
Published: November 2015

Auroral brightness fluctuations have been studied visually and photoelectrically for some time. In 1961, Campbell and Rees reviewed the information then available and drew attention to the distinct characteristics of the phenomenon. In this paper the work since that time is reviewed, with particular emphasis on the power spectral densities of the fluctuation records. The existence of distinct peaks in these spectra is noteworthy.New data are presented that show the importance of the coherency spectrum and the large spatial extent of the fluctuations. No systematic motions of the fluctuating region are found.Evidence that the fluctuation peaks result from an increased energy per particle, rather than an increased particle flux, is reviewed and discussed.Possible types of mechanisms are summarized briefly.
Application of a New Method for Approximate Solutions and Error Estimates to Waveguide Discontinuity and Phased Array Problems
Authors: Amitay N. , Galindo V. 
Published: November 2015

Many electromagnetic boundary value problems can be put in the form y=Kx, where K is a scattering operator, y is a vector or function proportional to the incident field, and x represents the scattered field. A useful and common solution to these problems is obtained by approximating K by an Nth order degenerate operator so that y = KNxN.A number of authors formulated upper bounds to the error ∥x − xN∥ that are essentially equivalent, but which we found to be unnecessarily restrictive. A reformulation of the problem leads to a solution in terms of a Neumann series involving the difference operator K − KN with the range of KN properly extended to the range of K. This approach is found to yield, with much less restrictive conditions, close error estimates as opposed to bounds. In fact, for some otherwise intractable scattering problems, this formulation converges so rapidly for N = 1 that an essentially closed form approximate solution may be written. Other salient features are also discussed together with examples and new physical results for a diverse class of boundary value problems including analysis of coaxial TE11 discontinuities and dielectric covered phased arrays.
Scattering By an Arbitrarily Shaped Conductor in Uniform Motion Relative to the Source of an Incident Spherical Wave
Authors: Ott R. H. , Hufford George 
Published: November 2015

We propose a method for analyzing the scattering of spherical waves by an arbitrarily shaped, perfectly conducting scatterer in relative motion with respect to the source and observation points. To treat this problem more rigorously, we use relativistic notation.Since the scatterer is arbitrarily shaped (the surface is assumed convex and closed), physical‐optics currents are assumed. These currents are found by transforming the incident field to the moving frame of the scatterer using the Lorentz transformation. The scattered field is derived in the scatterer's frame using the method of stationary phase. The scattered field is then transformed to the frame containing the source of the incident field.A method for finding the geometrical optics scattered field is derived. By‐products of the approach yield: (1) the angular frequency of the incident wave in the scatterer's frame, (2) a technique for finding the stationary phase points, and (3) a formula for calculating the frequency of the scattered field in the observer's frame.
The Finite Tubular Antenna in a Warm Plasma
Authors: David Wunsch A. 
Published: November 2015

A cylindrical dipole antenna, immersed in a warm homogeneous and isotropic plasma and driven at the center by a delta‐function voltage generator, is treated as a boundary value problem. The current on the antenna is determined and found to consist of two parts: a slowly varying component that varies like the current on an antenna in a cold medium, and an oscillating component. The spatial periodicity of the oscillatory component is of the same order as that of the surface waves launched on an infinite tube containing and surrounded by warm plasma. If the antenna is driven well above the plasma frequency, the oscillatory portion of the current is negligible, while if it is driven at slightly above the plasma frequency, the oscillatory portion of current is dominant.It is found that a radiation resistance calculation made by using a current distribution valid only for an antenna in a cold environment can be incorrect when applied to an antenna in a warm plasma.
Fault detection and isolation for uncertain closed‐loop systems based on adaptive and switching approaches
Authors: Li Xiao‐Jian , Yang Guang‐Hong 
Published: November 2015

SummaryThis paper deals with the fault detection and isolation (FDI) problem for uncertain closed‐loop systems with external disturbances and nonlinear perturbations. To address the system uncertainties and the nonlinear perturbations in different faulty models, adaptive and switching techniques are introduced to construct a bank of FDI observers, such that one of them can match the current system, and the corresponding observer estimate errors can converge asymptotically to zero. An effective FDI scheme is then presented by introducing some model‐matching indexes. Moreover, the introduced switching laws liberate the equality constraints often used in the existing FDI approaches, which are hard to satisfy if the system matrices include uncertainties. Finally, a simulation example of F/A‐18A automatic carrier landing system is used to illustrate the effectiveness of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.
When to automate software testing? A decision‐support approach based on process simulation
Authors: Garousi Vahid , Pfahl Dietmar 
Published: November 2015

AbstractSoftware test processes are complex and costly. To reduce testing effort without compromising effectiveness and product quality, automation of test activities has been adopted as a popular approach in software industry. However, because test automation usually requires substantial upfront investments, automation is not always more cost‐effective than manual testing. To support decision‐makers in finding the optimal degree of test automation in a given project, we recently proposed a process simulation model using the System Dynamics modeling technique and used the simulation model in the context of a case study with a software company in Calgary, Canada. With the help of the simulation model, we were able to evaluate the performance of test processes with varying degrees of automation of test activities and help testers choose the most optimal cases. The goal of the earlier study was to investigate how the simulation model can help decision‐makers decide whether and to what degree the company should automate their test processes. In this article, we present further details of the System Dynamics model, its usage scenarios and examples of simulation experiments independent from a specific company context. Copyright © 2015 John Wiley & Sons, Ltd.
Using Zinc Finger Nuclease Technology to Generate CRX-Reporter Human Embryonic Stem Cells as a Tool to Identify and Study the Emergence of Photoreceptors Precursors During Pluripotent Stem Cell Differentiation
Authors: Collin Joseph , Mellough Carla B , Dorgau Birthe , Przyborski Stefan , Moreno-Gimeno Inmaculada , Lako Majlinda 
Published: November 2015

Abstract
The purpose of this study was to generate human embryonic stem cell (hESC) lines harboring the green fluorescent protein (GFP) reporter at the endogenous loci of the Cone-Rod Homeobox (CRX) gene, a key transcription factor in retinal development. Zinc finger nucleases (ZFNs) designed to cleave in the 3′ UTR of CRX were transfected into hESCs along with a donor construct containing homology to the target region, eGFP reporter, and a puromycin selection cassette. Following selection, polymerase chain reaction (PCR) and sequencing analysis of antibiotic resistant clones indicated targeted integration of the reporter cassette at the 3′ of the CRX gene, generating a CRX-GFP fusion. Further analysis of a clone exhibiting homozygote integration of the GFP reporter was conducted suggesting genomic stability was preserved and no other copies of the targeting cassette were inserted elsewhere within the genome. This clone was selected for differentiation towards the retinal lineage. Immunocytochemistry of sections obtained from embryoid bodies and quantitative reverse transcriptase PCR of GFP positive and negative subpopulations purified by fluorescence activated cell sorting during the differentiation indicated a significant correlation between GFP and endogenous CRX expression. Furthermore, GFP expression was found in photoreceptor precursors emerging during hESC differentiation, but not in the retinal pigmented epithelium, retinal ganglion cells, or neurons of the developing inner nuclear layer. Together our data demonstrate the successful application of ZFN technology to generate CRX-GFP labeled hESC lines, which can be used to study and isolate photoreceptor precursors during hESC differentiation.
Unified analysis of transmit, receive and hybrid diversity techniques over generalized‐K channels
Authors: Yılmaz Ahmet , Kucur Oğuz 
Published: November 2015

AbstractIn this work, unified performance analysis of various transmit, receive and hybrid diversity techniques are studied over generalised‐K composite fading channels. Of transmit diversity techniques, orthogonal space‐time block coding, maximal‐ratio transmission and transmit antenna selection techniques are investigated. On the other hand, maximal‐ratio combining and selection combining are examined as receive antenna diversity techniques. In this paper, 10 different multi‐antenna techniques have been analyzed. Exact outage probability, symbol error probability, moment generating function, moments and ergodic capacity expressions are derived in closed‐form. Asymptotic expressions are also derived in order to provide deeper insight by obtaining array and diversity gains of the studied multi‐antenna scenarios. Simulations verify theoretical results. We show that the diversity orders of the investigated scenarios are the minimum of the diversity orders of the system for only small‐scale fading channel case and the shadowing parameter, and limited by the shadowing effect especially in heavy shadowing case. Copyright © 2015 John Wiley & Sons, Ltd.
Lanthanum (Oxo)nitridosilicates: From Ordered to Disordered Crystal Structures
Authors: Durach Dajana , Schnick Wolfgang 
Published: November 2015

AbstractThe homeotypic compounds La16.32Ba1.82Sr7.86[Si60N92.32O3.68]O12 and La13.68Sr12.32[Si60N96]F6.32O5.68 were synthesized at high temperature (1600/1500 °C) in a radio‐frequency furnace. The crystal structures [I$\bar{4}$m (no. 217), Z = 1, a = 13.3360(10)/13.3258(10) Å and V = 2371.8(5)/2366.4(5) Å3] were solved and refined on basis of single‐crystal X‐ray diffraction data and were corroborated by lattice‐energy calculations (Madelung part of lattice energy, MAPLE) powder X‐ray diffraction data and FTIR spectroscopy. They consist of a three‐dimensional network of allside corner sharing SiN4–xOx tetrahedra. The framework is characterized by double dreier rings. La16.32Ba1.82Sr7.86[Si60N92.32O3.68]O12 represents an oxonitridosilicate oxide and La13.68Sr12.32[Si60N96]F6.32O5.68 a nitridosilicate fluoride oxide, as the crystal structures contain non‐condensed (O[0]/O,F[0]) anions. The first compound is isotypic to Sr3Ln10Si18Al12O18N36 (Ln = Ce, Pr, Nd; Z = 2), whereas the latter describes a disordered model of the crystal structure, which is homeotypic to the mentioned SiAlONs.
Kopfumfang bei Kindern und Jugendlichen in Deutschland
Authors: Schienkiewitz Anja , Schaffrath-Rosario Angelika , Neuhauser Hannelore K. 
Published: November 2015

Zusammenfassung
Der Kopfumfang zählt zu den wichtigsten anthropometrischen Messgrößen, die im Kindes- und Jugendalter untersucht werden, um frühzeitig Hinweise auf eine abweichende Entwicklung des Gehirns zu geben. Vom Robert Koch-Institut wurde von 2003 bis 2006 die „Studie zur Gesundheit von Kindern und Jugendlichen in Deutschland (KiGGS)“ durchgeführt. Der Kopfumfang wurde bei über 17.000 Kindern und Jugendlichen standardisiert gemessen und geschlechtsspezifische Perzentilkurven, die in diesem Beitrag vorgestellt werden, mit statistischen Analyseverfahren modelliert. Über den gesamten Altersbereich zeigt sich, dass Jungen einen größeren Kopfumfang haben als Mädchen. Das Kopfwachstum ist im ersten Lebensjahr am stärksten und nimmt dann deutlich ab. Erst vor der Pubertät nimmt das jährliche Wachstum wieder zu. Im Alter von 16 Jahren ist das Kopfwachstum bei Mädchen beendet, während es bei Jungen noch bis zum Ende des beobachteten Altersbereichs (18. Lebensjahr) zunimmt. Der mediane Kopfumfang beträgt zu diesem Zeitpunkt bei Mädchen 55 cm und bei Jungen 57 cm. Mit der KiGGS-Studie stehen valide Daten zur Bewertung des Kopfumfangs von Kindern und Jugendlichen in Deutschland zur Verfügung. Neben den tabellierten Perzentilen kann auch jedes weitere relevante Perzentil für den gesamten Bereich des Kindes- und Jugendalters berechnet werden.
Auswirkungen des demographischen Wandels auf die regionale Bevölkerungsdynamik in Deutschland
Authors: Swiaczny Swiaczny 
Published: November 2015

Regional consequences of demographic change in Germany, the future ageing and the shrinking of the population, strongly depend on the development of internal migration. Based on current trends, it cannot be predicted how this will change under conditions of aging and population shrinking. Though they only reach until the 2030s, recent model calculations indicate that competition between places of residence will increase and that regional disparities of population development will further intensify in the future. Based on forward projections of previous trends, these model calculations tend to present the long-term population development in suburban and rural regions—which have in parts strongly benefited from internal migration—rather too positively.
The model calculation presented in this study is based on the assumption, that for differentiating population growth by internal migration, there have been other patterns in the past than this will be the case for the future, in which the population will decline in total. Based on a concentration of an expected long-term decline of the population in less attractive, structurally weak regions the model calculation shows, that beyond 2030 even such rural and suburban regions will experience a substantial population decline which still have, according to current trends, comparatively positive perspectives.
An overlap of Brugada syndrome and arrhythmogenic right ventricular cardiomyopathy/dysplasia
Authors: Kataoka Shohei , Serizawa Naoki , Kitamura Kazutaka , Suzuki Atsushi , Suzuki Tsuyoshi , Shiga Tsuyoshi , Shoda Morio , Hagiwara Nobuhisa 
Published: November 2015

AbstractOverlapping characteristics of Brugada syndrome (BrS) and arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) have been reported in recent studies, but little is known about the overlapping disease state of BrS and ARVC/D. A 36‐year‐old man, hospitalized at our institution for syncope, presented with this overlapping disease state. The electrocardiogram showed spontaneous coved‐type ST‐segment elevation, and ventricular fibrillation was induced by right ventricular outflow tract stimulation in an electrophysiological study. BrS was subsequently diagnosed; additionally, the presence of epsilon‐like waves and right ventricular structural abnormalities met with the 2010 revised task force criteria for ARVC/D. After careful investigation for both BrS and ARVC/D, an implantable cardioverter defibrillator was inserted in the patient. This case revealed 2 important clinical findings: (1) BrS and ARVC/D clinical features can coexist in a single patient, and EPS might be useful for determining the phenotype of overlapping disease (e.g., BrS‐like or ARVC/D‐like). (2) An overlapping disease state of BrS and ARVC/D can change phenotypically during its clinical course. Therefore, careful examination and attentive follow‐up are required for patients with BrS or ARVC/D.
Treatment for Positive Urine Cultures in Hospitalized Adults: A Survey of Prevalence and Risk Factors in 3 Medical Centers
Authors: Grein Jonathan D. , Kahn Katherine L. , Eells Samantha J. , Choi Seong K. , Go-Wheeler Marianne , Hossain Tanzib , Riva Maya Y. , Nguyen Megan H. , Rekha Murthy A. , Miller Loren G. 
Published: November 2015

BACKGROUNDAntibiotic treatment for asymptomatic bacteriuria (ASB) is prevalent but often contrary to published guidelines.OBJECTIVETo evaluate risk factors for treatment of ASB.DESIGNRetrospective observational study.SETTINGA tertiary academic hospital, county hospital, and community hospital.PATIENTSHospitalized adults with bacteriuria.METHODSPatients without documented symptoms of urinary tract infection per Infectious Diseases Society of America (IDSA) criteria were classified as ASB. We examined ASB treatment risk factors as well as broad-spectrum antibiotic usage and quantified diagnostic concordance between IDSA and National Healthcare Safety Network criteria.RESULTSAmong 300 patients with bacteriuria, ASB was present in 71% by IDSA criteria. By National Healthcare Safety Network criteria, 71% of patients had ASB; within-patient diagnostic concordance with IDSA was moderate (kappa, 0.52). After excluding those given antibiotics for nonurinary indications, antibiotics were given to 38% (62/164) with ASB. Factors significantly associated with ASB treatment were elevated urine white cell count (65 vs 24 white blood cells per high-powered field, P<.01), hospital identity (hospital C vs A, odds ratio, 0.34 [95% CI, 0.14–0.80], P =.01), presence of leukocyte esterase (5.48 [2.35–12.79], P<.01), presence of nitrites (2.45 [1.11–5.41], P=.03), and Escherichia coli on culture (2.4 [1.2–4.7], P=.01). Of patients treated for ASB, broad-spectrum antibiotics were used in 84%.CONCLUSIONSASB treatment was prevalent across settings and contributed to broad-spectrum antibiotic use. Associating abnormal urinalysis results with the need for antibiotic treatment regardless of symptoms may drive unnecessary antibiotic use.Infect. Control Hosp. Epidemiol. 2016;37(3):319–326
Streaming-potential phenomena in the thin-Debye-layer limit. Part 3. Shear-induced electroviscous repulsion
Authors: Schnitzer Ory , Yariv Ehud 
Published: November 2015

We employ the moderate-Péclet-number macroscale model developed in part 2 of this sequence (Schnitzer et al., J. Fluid Mech., vol. 704, 2012, pp. 109–136) towards the calculation of electroviscous forces on charged solid particles engendered by an imposed relative motion between these particles and the electrolyte solution in which they are suspended. In particular, we are interested in the kinematic irreversibility of these forces, stemming from the diffusio-osmotic slip which accompanies the salt-concentration polarisation induced by that imposed motion. We illustrate the electroviscous irreversibility using two prototypic problems, one involving side-by-side sedimentation of two spherical particles, and the other involving a force-free spherical particle suspended in the vicinity of a planar wall and exposed to a simple shear flow. We focus on the pertinent limit of near-contact configurations, where use of lubrication approximations provides closed-form expressions for the leading-order lateral repulsion. In this approximation scheme, the need to solve the advection–diffusion equation governing the salt-concentration polarisation is circumvented.