bluuebunny/crossref_metadata_2025_split huggingface dataset:
Optimizing de novo genome assembly from PCR-amplified metagenomes
Authors: Roux Simon , Trubl Gareth , Goudeau Danielle , Nath Nandita , Couradeau Estelle , Ahlgren Nathan A. , Zhan Yuanchao , Marsan David , Chen Feng , Fuhrman Jed A. , Northen Trent R. , Sullivan Matthew B. , Rich Virginia I. , Malmstrom Rex R. , Eloe-Fadrosh Emiley A. 
Published: May 2019

Background
Metagenomics has transformed our understanding of microbial diversity across ecosystems, with recent advances enabling de novo assembly of genomes from metagenomes. These metagenome-assembled genomes are critical to provide ecological, evolutionary, and metabolic context for all the microbes and viruses yet to be cultivated. Metagenomes can now be generated from nanogram to subnanogram amounts of DNA. However, these libraries require several rounds of PCR amplification before sequencing, and recent data suggest these typically yield smaller and more fragmented assemblies than regular metagenomes.

Methods
Here we evaluate de novo assembly methods of 169 PCR-amplified metagenomes, including 25 for which an unamplified counterpart is available, to optimize specific assembly approaches for PCR-amplified libraries. We first evaluated coverage bias by mapping reads from PCR-amplified metagenomes onto reference contigs obtained from unamplified metagenomes of the same samples. Then, we compared different assembly pipelines in terms of assembly size (number of bp in contigs ≥ 10 kb) and error rates to evaluate which are the best suited for PCR-amplified metagenomes.

Results
Read mapping analyses revealed that the depth of coverage within individual genomes is significantly more uneven in PCR-amplified datasets versus unamplified metagenomes, with regions of high depth of coverage enriched in short inserts. This enrichment scales with the number of PCR cycles performed, and is presumably due to preferential amplification of short inserts. Standard assembly pipelines are confounded by this type of coverage unevenness, so we evaluated other assembly options to mitigate these issues. We found that a pipeline combining read deduplication and an assembly algorithm originally designed to recover genomes from libraries generated after whole genome amplification (single-cell SPAdes) frequently improved assembly of contigs ≥10 kb by 10 to 100-fold for low input metagenomes.

Conclusions
PCR-amplified metagenomes have enabled scientists to explore communities traditionally challenging to describe, including some with extremely low biomass or from which DNA is particularly difficult to extract. Here we show that a modified assembly pipeline can lead to an improved de novo genome assembly from PCR-amplified datasets, and enables a better genome recovery from low input metagenomes.
Probable Controversy of Cardiac Resynchronization Therapy on the Adaptive Energy Metabolism of Hypertrophied and Insufficient Heart in Democratic Republic of Congo
Authors: Kunyima Papy K. , Lusamba Séraphin N. , Kunyima Anaclet B. 
Published: May 2019

Background: It is reported that 20 to 30% of patients are not responders to this treatment (Cardiac Resynchronization Therapy). The reasoning in this merely theoretical paper shows the plausible danger that can be brought by measurements apparatus, in the occurrence the CRT especially when it is sophisticated.
Objective: In Physical Cardiochemistry field our overall purpose is to bring a contribution to heart health. It is needful to draw attention for caregivers and manufacturers, especially with respect to the magnetism these apparatuses may exhibit.
Methods: The Observation and documentary research are used. It is recalled hereby successively energy metabolism in healthy cardiomyocyte, adaptive energy metabolism of a hypertrophied and insufficient heart, cardiac resynchronization therapy and energy metabolism of the cardiomyocyte with its potential effects on both glucose oxidation and fatty acids oxidation.
Results: It is shown a plausible interaction between oxygen magnetic field, paramagnetic by nature, and pacemaker and/or defibrillator electromagnetic field according to the sacral principle of “like dissolves like” with all evil consequences on patients.
Conclusion: It will be necessary to evaluate later not only the behavior of the various energetic substrates of a hypertrophied heart as a function of the variation of the magnetic field strength but also the content of the probable substances produced in the presence of a magnetic field and with a potentially harmful effect on cardiac function. Convinced technology has its setbacks, the pacemakers and/or defibrillators manufacturers are invited to a greater rigor, greater caution and sustained care in building these devices. In next publication study of a case (CRT-D), where the diabetes has been observed, will be outlined.
Determining Temperature Extreme in Warri City, Niger-Delta Region, Nigeria
Authors: Onifade Y. S. , Olaseni V. B. 
Published: May 2019

Climate change and global warming which is also known as a change in Earth’s overall climate or rising temperature have taken centre stage in international concerns, several fora and treaties have been observed with a view of stemming trend, in rising temperatures. This study evaluated ten years of maximum and minimum annual temperature of Warri in Nigeria between (2005 and 2015) to determine trends and identified extreme fluctuation in temperature. Data used for this study were sourced from the Nigerian Meteorological Agency’s Zonal Office, Warri. An objective method for determining temperature extreme has been used. Least square linear regression equation has been used to estimate temperature that would be equalled or surpassed 1%, 5% and 10% of the hours at any given location during the warmest and coldest months of the year. These equations are based on an index calculated from the three readily available parameters; the mean monthly temperature, the mean daily maximum temperature for the month and the mean daily minimum temperature for the month. The warmest month in Warri was March with a mean monthly temperature of 33.9 while the coldest month was July with mean monthly of 25.8.
Sero-prevalence and Risk Factors for Hepatitis A Virus Infection among Pregnant Women at the Samandin Medical Center, Ouagadougou, Burkina Faso
Authors: Hortense Rouamba Poda Somda , Bienvenue Ouoba Jean , Abdoulaye Traoré Kuan , Lalidia Ouoba Bruno , Asséta Kagambéga , Pierre Roques , Nicolas Barro 
Published: May 2019

Aims: This study determined prevalence and possible risk factors associated with HAV infection and compared Immunochromatography (IgG) rapid point of care test with standard ELISA test for diagnosis.
Study Design: Cross sectional epidemiological survey.
Place and duration of Study: The study was carried out at the Samandin Medical Center (Ouagadougou, Burkina Faso), from July 2017 to December 2017.
Methodology: A total of 180 pregnant women were recruited at the Samandin Medical Center. Anti-HAV IgM and IgG detection tests were performed using AccuDiag™ HAV ELISA kit (Calabasas, CA, USA) and SD BIOLINE HAV IgG/IgM Rapid Diagnostic Test (Gyeonggi-do, Korea).
Results: IgG anti-HAV antibodies (AccuDiag Elisa) were found with a prevalence of 88.9% (160/180) and Anti-HAV IgM were 1.1% (2/180). Of the 160 AccuDiag HAV IgG positive samples, 44.4% (80/180) tested positive using SD BIOLINE Diagnostics HAV IgG. Regarding risk factors, 86.9% (86/99) of the IgG positive women were illiterate; 90.7% (39/43) lived mostly in peripheral areas; 89.2% (74/83) were household workers and 88.6% (93/105) used fountain water.
Conclusion: Our results demonstrated poor agreement between the assays tested, which are consistent with previous reports demonstrating significant variability between HAV ELISA and RDT HAV. Moreover, the detection of HAV specific IgM antibodies in two asymptomatic pregnant women signaled the current circulation of HAV in this area.
Synthesis, Characterization and Complexation Behaviour of Chloroquine towards Ti (II) Ion
Authors: Otuokere I. E. , Okpara L. O. , Amadi K. C. , Alisa C. O. , Okoyeagu A. , Nwadire F. C. 
Published: May 2019

Aims: Chloroquine is a member of the drug class 4-aminoquinoline used for the prevention and treatment of malaria in areas where malaria is known to be sensitive to its effects.
Our aim is to synthesize the chloroquine – titanium complex and to study its coordination behavior.
Place and Duration of Study: Department of Chemistry, Michael Okpara University of Agriculture, Umudike, 2019.
Methodology: Ti(II) complex of chloroquine was synthesized by the reaction of chloroquine phosphate with titanium(IV) oxide. The metal complex was characterized based on UV, IR and 1H NMR Spectroscopy.
Results: The UV spectrum of the complex suggested intra ligand charge transfer (ILCT), ligand to metal charge transfer (LMCT), and d-d transition. The IR spectrum of the complex showed the involvement of amine and imine group in coordination to Ti. This showed that chloroquine acted as a bidentate ligand. 1H NMR of the spectrum further showed the involvement of the amine group in coordination.
Conclusion: The ability of chloroquine to sequestrate Ti (II) ion has been assured. This drug can be used to chelate Ti ions from solution, environment, and biological system.
Helical Antennas
Authors: Adams Arlon T. , Lee Jay K. 
Published: November 2024

AbstractThe helical antenna operates in several different modes. At lower frequencies, thenormalmode predominates, with a beam pattern similar to that of a dipole along the helix axis. As frequency increases and helix circumference approaches one wavelength, two new modes appear. Theaxialmode radiates along the forward direction of the helix axis. It is broadband and circularly polarized. Thebackfiremode radiates along the backward direction of the helix axis, scanning forward in a conical beam as frequency increases.The quadrifilar helices, along with other multifilar helices, show many of the characteristics of the monofilar helix with some important differences. All three modes are exhibited. The bandwidth of theaxialmode is increased roughly in proportion to the number of wires. Thebackfirequadrifilar helix is useful for mobile communications.The radiation theory of the helix antennas is outlined. Numerous applications of the different modes are presented. Recent work on human proximity effects is noted.
Loop Antennas
Authors: Siwiak Kazimierz 
Published: November 2024

Abstract
Loop antennas are simple and versatile structures that appear as communication antennas in diverse applications, including pager receivers and massive multielement transmitting arrays. They are analyzed here in electrically small form as nonresonant magnetic field probes, as efficient resonated small antennas, and as large self‐resonant antennas. A rigorous generalized loop analysis in this article reveals details of the current density both along the loop circumference and around the wire circumference. Expressions are given for the loop impedance and loop near fields. The relatively low near‐field wave impedances make loops particularly suitable for body proximate receiving devices, while in the full‐wavelength‐sized structures, where very high transmitter power levels are required, they are suitable because they are not prone to high voltage corona discharge problems.
Microstrip Antennas
Authors: How Hoton 
Published: November 2024

AbstractThis article introduces two calculational methods capable of describing quantitatively the antenna performance. The first method, calledresonant cavity model, is less rigorous but nevertheless has the advantage of being more analytical and, hence, it can be applied with ease. The cavity model is considered inappropriate for a microstrip structure showing a thick substrate, or if the dielectric constant of the substrate is large, because under these conditions excitation of surface waves is significant. The second calculational method concerns the Green function analysis. AGreen functionis defined as the solution of a differential/integral equation under a point source excitation satisfying homogeneous boundary conditions. By using the dyadic Green's functions, the general field solution in a stratified structure excited by external current sources can then be formulated in terms of an integral equation, which is subsequently solved by applying the numerical Galerkin method. This article outlines procedures to calculate the engineering parameters of a microstrip antenna of an arbitrary geometry, and it illustrates calculational results on circular microstrip antennas, showing plots in radiation frequencies, bandwidths, far‐field patterns, input impedances, effects in feeder‐line positions, and interference between antennas. The dyadic Green's functions involving anisotropic/gyromagnetic materials are also introduced, and the transfer matrix technique is explained. A transfer matrix translates the tangential components of the electromagnetic field over one layer of a stratified structure satisfying the boundary conditions therein. Recent developments on printed circuit antennas are reviewed, including the important broadband techniques employing stacked parasitic elements to achieve high gain and low cross‐polarization level. Fractal antennas involving a patch geometry exhibiting a fractional dimension are then introduced.
Uniform Geometrical Theory of Diffraction
Authors: Pathak Prabhakar H. 
Published: November 2024

Abstract
Keller's geometrical theory of diffraction (GTD) [1,2] constitutes a major breakthrough for solving problems of electromagnetic (EM) radiation and scattering at high frequencies. The GTD can also be applied to solving acoustic and elastic wave problems; however, only the EM case is discussed here.
Recently, the development of fast solvers for signifi‐cantly increasing the efficiency of numerical methods in solving large problems has met with some success. However, for truly large problems, asymptotic high‐frequency methods in general, and especially ray methods such as the GTD and its uniform version, still remain the most useful analysis tools.
Wideband Slot and Printed Antennas
Authors: Elsherbeni Atef Z. , Eldek Abdelnasser A. , Smith Charles E. 
Published: November 2024

AbstractWideband antennas are in great demand for many of today's and future applications. This chapter presents new types of printed and slot antennas that support wideband applications centered at 10 GHz. The slot antennas are fed by coplanar waveguides and the printed antennas are fed by a microstrip lines. Sixteen elements of the printed antenna provides 71% bandwidth with scanning capabilities up to 50° without grating lobes. Sample designs of reconfigurable slot and microstrip patch antennas are also presented to provide mechanism for using narrow bandwidth antennas in wideband applications.
Superconducting Electromagnets
Authors: Williams John E.C. 
Published: November 2024

AbstractThe design and construction of superconducting magnets has been made possible by the development of technical superconductors. There are three principal materials: the alloy niobiumtitanium (NbTi), the intermetallic compound niobiumtin (Nb3Sn), and the collective high‐temperature superconductors (HTSs) based on copper oxide layers in a perovskite structure.Technical superconductors are a class having special properties that allow superconductor operation in high magnetic fields and with useful current densities. Superconductors are of two types; both can support the flow of electrical current without resistance only below a combination of maximum temperature, field, and current density, with critical parametersTc,Bc, andJc[1]. For type I superconductors, typical values ofTcandBcare 9 K and 0.1 T, respectively. Flux is excluded from the bulk of a type I superconductor, and current flows only in a surface layer, about 10−4 mm thick.By contrast, type II superconductors allow flux to penetrate into the bulk of the lattice in the form of an array of flux quanta.
Transmitters for Digital Television
Authors: Weirather Robert 
Published: November 2024

Abstract
Digital television for over‐the air broadcasting requires high‐power transmitters. Transmitters with high peak power and excellent linearity are required. Combined transistors and vacuum tubes are used to amplify the coded orthogonal frequency‐division multiplex (COFDM) or eight‐level vestigial sideband quadrature amplitude modulation (8 VSB) to kilowatts of RF power.
Pulse‐Shaping Circuits
Authors: Myers Brent A. , Chester David B. 
Published: November 2024

Abstract
Pulse shaping is used in the implementation of digital communication systems to minimize ISI caused by nonideal channel characteristics and nonideal component implementations.
Pulseshaping is performed in the transmit and receive filters of a communication system. The most common class of filters used for pulseshaping are Nyquist filters [13]. This article gives an overview of the theoretical foundations of pulseshaping and describes some practical implementations of pulseshaping filters.
Signal Fading in Radio Communications
Authors: Janaswamy Ramakrishna 
Published: November 2024

Abstract
In this article we describe the causes of signal fluctuation in wireless systems and describe the phenomena of short‐term and long‐term fading. Some of the topics included are narrowband and wideband fading, Rayleigh fading, Ricean fading, lognormal fading, level crossing rates, average fade duration, channel coherence time, Doppler spread, delay spread, and coherence bandwidth. The impact of fading on the performance of systems and in the design of cell size is discussed.
Direct Satellite Television Broadcasting
Authors: Godwin John P. 
Published: November 2024

Abstract
Direct‐to‐home (DTH) satellite television broadcasting has no strict technical or legal definition. Since the late 1970s the term has been used to delineate commercial systems that deliver television directly to consumer homesusing communication satellites in geosynchronous orbit.
This article describes the broadcasting and reception systems of a typical digital DTH broadcasting system, but does not cover the substantial infrastructure necessary for customer service and billing.
Galerkin Method (Rayleigh–Ritz Method)
Authors: Weile Daniel S. , Wildman Raymond A. , Pisharody Greeshma , Mohan Anuraag 
Published: November 2024

Abstract
Galerkin's method and the Rayleigh–Ritz method form the mathematical underpinnings of many modern computational techniques for the solution of electromagnetics problems. In this work, the history of these two methods is reviewed, and each of the methods is described in detail. The relationship between the methods is explored, as is their relationship with the modern finite‐element method and method of moments. Numerical examples of the methods are provided to clarify the exposition.
Integro‐Differential Equations
Authors: Garcia Manuel 
Published: November 2024

Abstract
This article discusses a variety of methods and approximations used to solve and calculate integrodifferential equations, with emphasis, is on the utilitarian rather than the theoritical. Integrodifferential equations can describe linear and nonlinear systems that have memory, or are not in equilibrium. The appearance of both derivatives and integrals in an equation (e.g., expressing some type of balance with respect to time) means that instantaneous rates (e.g., velocity) and accumulated history (e.g., metal fatigue) determine the state of the system at the present moment. It is this aspect of integrodifferential equations that gives them their intellectual appeal, wide applicability, and challenging nature.
Electromagnetic Ferrite Tile Absorber
Authors: Holloway Christopher L. , Baker–Jarvis James R. , Johnk Robert T. , Geyer Richard G. 
Published: November 2024

AbstractIn this chapter, we discuss the ferrite tile, ferrite grids, and hybrid combinations of urethane and ferrite absorbers typically used in electromagnetic test chambers for the 30MHz to 1000MHz frequency range. We present formulas and calculated reflectivities (or reflection coefficients). We also discuss how material properties and reflectivities are measured for the ferrite‐tile absorbers.
Cavity Resonators
Authors: Sharma Arvind K. 
Published: November 2024

AbstractIn this article, a brief description of the cavity resonators most commonly employed in various microwave components is presented. As far as possible, simple expressions have been provided for design applications. Basic parameters of microwave resonators are first presented because they describe a cavity. Then, various coaxial and waveguide resonators are described. Fabrication, coupling, measurements, and applications of cavity resonators are also included.
Coupled Transmission Lines
Authors: Paul Clayton R. 
Published: November 2024

Abstract
Two transmission lines whose electromagnetic fields are coupled induce signals from one line into another. This coupling is either intentional as in directional couplers or unintentional, producing unwanted responses in the other line, which is referred to as crosstalk. This discussion of coupled transmission lines will concentrate on the analysis of coupled lines and can be used to design intentional coupling or to assess unintentional coupling as in crosstalk.
Maxwellian Circuits
Authors: Mei Kenneth K. 
Published: November 2024

AbstractA Maxwellian circuit is defined as a discretized equivalent circuit of a wire structure, the solution of which is the same as that of the Maxwell's equations satisfying the same boundary conditions of the circuit. The theory of Maxwellian circuits is based on the existence and uniqueness theorems of equivalent differential equations of each thin‐wire‐type integral equation, which is derived from Maxwell's equations. In this article, the proofs of the basic theorems are presented, calculations verifying the theory are shown in figures, and related applications are discussed.
Microwave Power Amplifiers
Authors: Colantonio Paolo , Giannini Franco , Limiti Ernesto 
Published: November 2024

AbstractMicrowave Power are discussed, focusing mainly on solid‐state implementations. Starting with an introduction on solid‐state and vacuum device power generating capabilities and solid‐state active realization technologies and materials, this article introduces and defines the basic quantities defining and characterizing a microwave power amplifier. The basic concepts of operating class and the relevant expected performances are addressed, including reference cases. Power balance considerations are inferred and high‐efficiency power amplifier design techniques are detailed, including both harmonic tuning approaches and switched‐mode amplifier schemes. Measurement‐based approaches (load pull) and computer‐aided design techniques are also discussed.
Periodic Structures
Authors: Bozzi Maurizio 
Published: November 2024

AbstractThis article gives an overview of periodic structures commonly used in the microwave and millimeter‐wave frequency range. The operation principle of the most significant components, their applications and the classical fabrication technologies are described. The basic theory of the propagation of electromagnetic fields in periodic structures is reported, and includes Floquet's theorem and Brillouin zones. Some numerical methods typically adopted for their analysis are described and discussed.