bluuebunny/crossref_metadata_2025_split huggingface dataset:
RNA:DNA triple helices: from peculiar structures to pervasive chromatin regulators
Authors: Greifenstein Andreas Adam , Jo SoYoung , Bierhoff Holger 
Published: April 2021

Abstract
The genomes of complex eukaryotes largely contain non-protein-coding DNA, which is pervasively transcribed into a plethora of non-coding RNAs (ncRNAs). The functional importance of many of these ncRNAs has been investigated in the last two decades, revealing their crucial and multifaceted roles in chromatin regulation. A common mode of action of ncRNAs is the recruitment of chromatin modifiers to specific regions in the genome. Whereas many ncRNA–protein interactions have been characterised in detail, binding of ncRNAs to their DNA target sites is much less understood. Recently developed RNA-centric methods have mapped the genome-wide distribution of ncRNAs, however, how ncRNAs achieve locus-specificity remains mainly unresolved. In terms of direct RNA–DNA interactions, two kinds of triple-stranded structures can be formed: R-loops consisting of an RNA:DNA hybrid and a looped out DNA strand, and RNA:DNA triple helices (triplexes), in which the RNA binds to the major groove of the DNA double helix by sequence-specific Hoogsteen base pairing. In this essay, we will review the current knowledge about RNA:DNA triplexes, summarising triplex formation rules, detection methods, and ncRNAs reported to engage in triplexes. While the functional characterisation of RNA:DNA triplexes is still anecdotal, recent advances in high-throughput and computational analyses indicate their widespread distribution in the genome. Thus, we are witnessing a paradigm shift in the appreciation of RNA:DNA triplexes, away from exotic structures towards a prominent mode of ncRNA–chromatin interactions.
Energy and spectral efficient relay selection and resource allocation in mobile multi‐hop device to device communications
Authors: Selmi Sawsan , Bouallègue Ridha 
Published: April 2021

AbstractThe expansion of smart devices and throughput requirements have triggered the integration of multi‐hop Device to Device (D2D) underlay the fifth generation (5G) network. This new paradigm has extended the coverage area and enabled ultra‐low latency and cost‐per‐bit communications. While the previous 3GPP releases address only the coverage problem via two‐hop D2D, this paper focuses on multi‐hop D2D defined in 3GPP release 15 and beyond. It proposes a distributed relay selection and resource allocation algorithm based on a mixed strategy game and a novel amplify and forward factor. The proposed schema maximizes the joint spectral and energy efficiency. Besides, it determines the optimal amount of data and energy transferred by each device. The efficiency of this approach against other state‐of‐the‐art solutions is evaluated and verified through computer simulations.
Coconut trees detection and segmentation in aerial imagery using mask region‐based convolution neural network
Authors: Iqbal Muhammad Shakaib , Ali Hazrat , Tran Son N. , Iqbal Talha 
Published: April 2021

AbstractFood resources face severe damages under extraordinary situations of catastrophes such as earthquakes, cyclones, and tsunamis. Under such scenarios, speedy assessment of food resources from agricultural land is critical as it supports aid activity in the disaster‐hit areas. In this article, a deep learning approach was presented for the detection and segmentation of coconut trees in aerial imagery provided through the AI competition organised by the World Bank in collaboration with OpenAerialMap and WeRobotics. Masked Region‐based Convolution Neural Network (Mask R‐CNN) approach was used for identification and segmentation of coconut trees. For the segmentation task, Mask R‐CNN model with ResNet50 and ResNet101 based architectures was used. Several experiments with different configuration parameters were performed and the best configuration for the detection of coconut trees with more than 90% confidence factor was reported. For the purpose of evaluation, Microsoft COCO dataset evaluation metric namely mean average precision (mAP) was used.An overall 91% mean average precision for coconut trees’ detection was achieved.
3D object recognition with a linear time‐varying system of overlay layers
Authors: Sohrabi Nasrabadi Mohammad , Safabakhsh Reza 
Published: April 2021

AbstractObject recognition is a challenging task in computer vision with numerous applications. The challenge is in selecting appropriate robust features with tolerable computing costs. Feature learning attempts to solve the feature extraction problem through a learning process using various samples of the objects. This research proposes a two‐stage optimization framework to identify the structure of a first‐order linear non‐homogeneous difference equation which is a linear time‐varying system of overlay layers (LtvoL) that construct an image. The first stage consists of the determination of a finite set of impulses, called overlay layers, by the application of a genetic algorithm. The second stage defines the coefficients of the corresponding difference equation derived from L2 regularization. Classification of the test images is possible by a novel process exclusively designed for this model. Experiments on the Washington RGB‐D dataset and ETH‐80 show promising results which are comparable to those of state‐of‐the‐art methods for RGB‐D‐based object recognition.
A novel circularly polarized slotted substrate integrated waveguide antenna array for satellite applications
Authors: Eid Alla M. , Salama Amgad A. , Elkamchouchi Hassan M. 
Published: April 2021

AbstractIn this article, three novel slotted substrate integrated waveguide (SIW) antenna elements are demonstrated with different radiator configurations, namely, two arms Archimedean antenna, single‐arm spiral antenna (monofilar), and four concentric circular loops antenna. Additionally, their near, as well as far‐field characteristics, have been investigated. The two arms Archimedean spiral antenna has a superior radiation characteristic of 18% return loss bandwidth (RLBW), 12% boresight axial ratio bandwidth (ARBW), and five dBi directivity. Furthermore, a 1 × 10 slotted SIW travelling wave antenna array has been designed, fabricated, and measured. The performance of the proposed antenna array versus the last reported antenna was evaluated and the proposed antenna array performance is superior to that of the others. Moreover, the measurements of the proposed array have a good agreement with the simulation results in which, 35%, 13% RLBW, and ARBW, respectively, have been achieved. The directivity of the proposed antenna array is 14 dBi.
Collocated MIMO travelling wave SIW slot array antennas for millimetre waves
Authors: Ghalib Asim , Sharawi Mohammad S. , Mittra Raj , Attia Hussein , Shammim Atif 
Published: April 2021

AbstractA novel four‐element collocated travelling wave substrate integrated waveguide (SIW) multiple‐input multiple‐output (MIMO) antenna covering millimetre wave (mm‐wave) bands (28–32 GHz) is presented. The antenna exhibits a matching bandwidth of more than 4 GHz and a measured gain of 15 dBi. The MIMO antenna elements are collocated, thus significantly reducing the size of the proposed design. To spatially isolate the beams (obtain lower correlation coefficient) of the MIMO antenna elements, the beams are oriented in different directions. The slots within each SIW array are designed to provide tilted beams, thus eliminating the need for a beam switching network. Four distinct beams are formed towards ±10° and ±30°. The dimension of the four‐element MIMO SIW design is 68 × 30.68 × 0.5 mm3. The proposed antenna has a high gain, compact size, simpler feeding and enhanced MIMO capability compared to other SIW antennas proposed in the literature.
Design of compact planar power divider with wideband bandpass response and high in‐band isolation
Authors: Wang Xuedao , Wang Jianpeng , Zhu Lei , Choi Wai‐Wa , Wu Wen 
Published: April 2021

AbstractIn this study, a compact planar power divider (PD) with wideband bandpass response is proposed based on a coupled three‐line filtering prototype. With two back‐to‐back microstrip feeding lines and a coplanar waveguide resonator located in the middle ground plane, the filtering structure is constructed. According to the synthesis approach, the proposed filtering structure can achieve an equal in‐band ripple response with three transmission poles and four out‐of‐band transmission zeros. In order to make the proposed PD inherit the designed filtering performance, one of the output lines in the filter network is modified to realize a 50 to 25 Ω impedance transformation in the passband first. Then, for good in‐band isolation and impedance matching at output ports, the modified output line is split into two separated lines by a slot so that a lumped resistor can be loaded at the ends of the two separated output lines. By properly setting the slot width and the resistance with guidance, high isolation level over an ultra‐wide passband is attained. For demonstration, three cases of the PDs with different bandwidths are designed on the basis of the corresponding filter designs. Finally, two bandpass PDs are fabricated and tested to verify the design concept.
Reference Ranges for Vermis Biometry on Prenatal Ultrasound: Systematic Review and Meta-Analysis
Authors: Rosenbloom Joshua I , Yaeger Lauren H. , Porat Shay 
Published: April 2021

Abstract
Purpose To conduct a systematic review and meta-analysis of published nomograms for fetal vermis biometry.
Materials and Methods A structured literature search was conducted to identify studies that reported normal measurements of the fetal vermis. A customized quality assessment tool was used to review the selected articles. Random effects meta-analysis was used to calculate normal ranges for vermian craniocaudal diameter, anteroposterior diameter, and surface area.
Results A total of 21 studies were included for qualitative review and 3 studies were included for quantitative synthesis. The 3 included articles comprised a total of 10 910 measurements from gestational ages 17–35 weeks. The quality assessment demonstrated that there was generally poor reporting regarding maternal characteristics and neonatal outcomes. Except for one article with a large sample size, the mean number of fetuses per week of gestational age was 15.9, with the lowest number being 5. There was significant statistical heterogeneity. Non-visualization rates ranged from 0–35.4 %. The craniocaudal diameter (reported in 3 articles) increased from a mean of 7.90 mm (95 % confidence interval [CI] 7.42, 8.38) at 17 weeks to 21.90 mm (95 % CI 20.63, 23.16) at 35 weeks gestation. The anteroposterior diameter (reported in 2 articles) increased from 6.30 mm (95 % CI 5.42, 7.18) at 17 weeks to 15.85 (95 %CI 15.49, 16.21) at 32 weeks.
Conclusion Reference ranges for vermis biometry across gestation based on meta-analysis of existing references are provided. However, because many of the underlying studies suffered from significant methodological issues, the ranges should be used with caution.
Case Report of a Benign Looking Malignant ECG–Value of Subtle Signs
Authors: Sharnagat Khushal Lokchand , Kodati Deepthi 
Published: April 2021

Abstract
ECG is one of the primary and most informative bedside tools for the cardiologist, even in the present era. Careful analysis of ECG changes (sometimes subtle) can be life-saving, such as in the case we are presenting now. A 42-year-old gentleman with no obvious coronary risk factors presented with vague pain and subtle ECG changes (outside physician passed off as usual). He was asked to consult a cardiologist. While awaiting outpatient consultation, he collapsed. The patient was resuscitated and coronary angiogram was immediately done, which showed distal left main disease. Successful intervention was carried out with the help of provisional stent strategy, and the patient was discharged safely.
Roads to Change: Livelihoods, Land Disputes, and Anticipation of Future Developments in Rural Kenya
Authors: Greiner Clemens , Greven David , Klagge Britta 
Published: April 2021

AbstractThis article examines how rural roads relate to differences in livelihood patterns, attitudes toward social change, and land disputes in Baringo, Kenya. Although their direct use is limited for many residents, roads have a highly differentiating impact. While some households orientate themselves toward roads, those relying more on (agro-)pastoralist livelihoods avoid their proximity. Our findings suggest that better-off households are not the only ones that tend to live closer to roads, but that poorer households do as well. Rather than by socio-economic status, households living closer to roads can be characterized by higher degrees of formal education and also appear to be more open to economic and social change. Our data also highlight dynamics of land disputes in the face of ongoing large-scale infrastructural investments in Kenya’s previously marginal northern drylands.
Versatile Seebeck and electrical resistivity measurement setup for thin films
Authors: Ferreira-Teixeira Sofia , Carpinteiro Francisco , Araújo João P. , Sousa João B. , Pereira André M. 
Published: April 2021

A custom setup for Seebeck coefficient and electrical resistivity measurements of thin films as a function of temperature in the range of 10–300 K was developed. The Seebeck coefficient is measured using a two-probe arrangement and using either a dynamical or steady/quasi-steady differential method. The temperature differences (ΔTs) for these measurements across the samples are achieved by using resistive heaters embedded in two copper blocks. The sample is screwed to these blocks and is in pressured contact with the measurement probes. The electrical resistivity is measured with a two-probe arrangement. To verify the reliability of the developed setup, measurement tests were performed on commercial niobium foil and a specular spin valve previously studied, having obtained a great accordance (within ∼3%) between this setup’s experimental results and the reference measurements.
Multiple independent recombinations led to hermaphroditism in grapevine
Authors: Zou Cheng , Massonnet Mélanie , Minio Andrea , Patel Sagar , Llaca Victor , Karn Avinash , Gouker Fred , Cadle-Davidson Lance , Reisch Bruce , Fennell Anne , Cantu Dario , Sun Qi , Londo Jason P. 
Published: April 2021

SignificanceWe studied the grape sex-determining region (SDR) in 12Vitisgenomes and demonstrated its conservation across 556 genotypes including 193 accessions from 47 world-wide wild grapevine species and 363 accessions of cultivated grapevine. Although the grape SDR is recombination free in all wild species, we found two distinct hermaphrodite (H) haplotypes (H1 and H2) among the cultivated grapevines, both chimeras of male (M) and female (f) haplotypes. The two independent recombinations carry different genetic signatures which long predate the domestication of grapevine, suggesting independent evolutions of this trait in wild European grapevine gene pools prior to human domestication.
Dynamical diffeomorphisms
Authors: Ferrero Renata , Percacci Roberto 
Published: April 2021

Abstract
We construct a general effective dynamics for diffeomorphisms of spacetime, in a fixed external metric. Though related to familiar models of scalar fields as coordinates, our models have subtly different properties, both at kinematical and dynamical level. The energy–momentum (EM) tensor consists of two independently conserved parts. The background solution is the identity diffeomorphism and the EM tensor of this solution gives rise to an effective cosmological constant.
Reissner–Nordström geometry counterpart in semiclassical gravity
Authors: Arrechea Julio , Barceló Carlos , Carballo-Rubio Raúl , Garay Luis J 
Published: April 2021

Abstract
We compute the renormalized stress–energy tensor (RSET) of a massless minimally coupled scalar field in the regularized Polyakov approximation, as well as its backreaction, on the classical Reissner–Nordström spacetime. The complete set of solutions of the semiclassical self-consistent equations is obtained and compared with their classical counterparts. The semiclassical Reissner–Nordström family involves three kinds of geometries that arise depending on the charge-to-mass ratio of the spacetime. In the under-charged regime, the geometry has its external horizon replaced by a wormhole neck that leads to a singular asymptotic region at finite proper distance. The over-charged regime reveals a naked singularity surrounded by a cloud of (infinite) mass coming from the quantized field. Between both behaviours there is a separatrix solution reminiscent of the extremal black hole classical geometry. As the RSET over an extremal horizon is finite, the semiclassical backreaction does not get rid of the horizon. Nonetheless, we show that the resulting horizon is singular.
The physical origin of Schrödinger equation
Authors: Yan Xiao-Bo 
Published: April 2021

Abstract
Quantum mechanics is one of the basic theories of modern physics. Here, the famous Schrödinger equation and the differential operators representing mechanical quantities in quantum mechanics are derived, just based on the principle that the translation invariance (symmetry) of a system in Hamiltonian mechanics should be preserved in quantum mechanics. Moreover, according to the form of the differential operators, the commutation relation in quantum mechanics between the generalized coordinate and the generalized momentum can be directly obtained. We believe that the results in this paper are very useful for understanding the physical origin of quantum mechanics.
Efficient ground state cooling of a membrane by the combination of continuous-wave field and pulses
Authors: Chen Zhi Xin , He Bing , Lin Qing 
Published: April 2021

Abstract
We present an approach that realizes the ground state cooling of the membrane-in-middle optomechanical system. Instead of straightforwardly using the continuous-wave (CW) or pulsed external drives, we consider the combinations of them for having a more efficient cooling process. Due to the dynamical nature of the joint action of both CW and pulse fields, it is necessary to explore the real-time evolutions of the system under various conditions, from which the optimal cooling can be found. Given such setup, the cooling limit previously discovered for the simple optomechanical systems under a single CW drive can be easily broken. The achieved cooling effect indicated by a defined cooling rate is one or more order lower than the cooling limit of a simple optomechanical systems, thus providing an efficient way of ground state cooling. Furthermore, the ground state cooling can be realized for a membrane with much lower mechanical quality factor and with the external drives of the lower intensities, to considerably relax the requirements for optomechanical cooling with the current experimental technology.
Theoretical investigations of e
±
–CO scattering
Authors: Billah M Masum , H Khandker Mahmudul , Shorifuddoza M , Sayed M A , Watabe Hiroshi , Haque A K F , Uddin M Alfaz 
Published: April 2021

Abstract
The differential, integrated elastic, total, momentum transfer, viscosity cross sections and spin-polarization for electron and positron elastic scattering from carbon monoxide (CO) molecule are calculated for the energy range of 1 eV–10 keV. The work also includes the calculations of inelastic and total ionization cross sections for the same scattering system. Calculations of the above scattering observables for CO over such a wide range of energy are reported for the first time. Single scattering independent atom model (IAM) and the screening correction within the same framework, are used for the present analysis. Dirac partial wave analysis is used to calculate the phase-shifts required for the generation of the scattering observables, using a complex optical model potential. Comparison of our calculated results with the available experimental observations and other theoretical calculations is presented. The screening corrected independent atom model is found to provide better description of the results than the IAM.
Probing adsorbates on La1−x
Sr
x
NiO3−δ
surfaces under humid conditions: implications for the oxygen evolution reaction
Authors: Carvalho O Quinn , Adiga Prajwal , Wang Le , Liu Jishan , Jia Endong , Du Yingge , Nemšák Slavomir , Stoerzinger Kelsey A 
Published: April 2021

Abstract
Earth-abundant nickel-containing perovskite oxides (ANiO3) are highly active materials for the oxygen evolution reaction (OER). The strong nickel-oxygen (Ni–O) covalency, tunable by A-site chemical substitution, contributes to both bulk and surface material properties like the formation of oxygen vacancies (v
••

O
) and OER activity. Here we quantify the coverage of OER relevant adsorbates on a series of La1−x
Sr
x
NiO3−δ
(LSNO, 0 ⩽ x ⩽ 0.5) epitaxial thin films exposed to humid environments by ambient pressure x-ray photoelectron spectroscopy. While all LSNO film compositions investigated here have comparable hydroxide coverages at the relative humidities (RHs) probed (1.5 × 10−5 – 0.2%RH), the amount of under-coordinated surface oxygen increases notably with Sr content. We interpret differences in the free energy of adsorption (ΔG
ads,i
) of these OER intermediates, inferred from adsorption isotherms, in the context of proposed v
••

O
-mediated OER mechanisms, consistent with the pH-dependent OER activity observed here for LSNO. We find that Sr incorporation enhances the affinity of LSNO surfaces for these under-coordinated oxygen species, in line with calculations in the literature.
Core−shell coaxially structured NiCo2S4@TiO2 nanorod arrays as advanced electrode for solid-state asymmetric supercapacitors
Authors: Qi Fangya , Li Han , Yang Fan , Sun Zhipeng 
Published: April 2021

Abstract
An integrated electrode of core–shell coaxially structured NiCo2S4@TiO2 nanorod arrays/carbon cloth (NiCo2S4@TiO2@CC) have been fabricated, via a two-step hydrothermal method. Comprehensive structural and compositional analyzes are performed to understand the effects of the NiCo2S4 shell on the TiO2 core. Such core–shell arrays structure can significantly provide abundant electroactive sites for redox reactions, convenient ion transport paths, and favorable structure stability. The NiCo2S4@TiO2@CC electrode represents a splendid specific capacitance (650 F g−1 at 1 A g−1) and enhanced cycling stability (capacitance retention of 97% over 10 000 cycles at 5 A g−1). Additionally, the assembled NiCo2S4@TiO2@CC//CNT@CC solid-state asymmetric supercapacitors exhibit a maximal energy density of 0.6 mWh cm−3 at 32.4 W cm−3, and topping cycling stability (85% capacitance retention after 5000 cycles at 5 mA cm−2). The results demonstrate that the well-designed NiCo2S4@TiO2@CC presented in this work are applicable for the development of electrode materials in energy storage devices.