bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced ribosomal RNA expression and unchanged ribosomal DNA promoter methylation in oral squamous cell carcinoma
Authors: Ha Shanshan , Zhou Hong , Gautam Mayank , Song Yaling , Wang Changning
Published: June 2019

Background

Ribosomal RNA (rRNA) consists of four non‐coding RNAs, the 28S, 5.8S, 18S, and 5S rRNA. Abnormal expression of rRNA has been found in multiple tumors, and the methylation of rDNA promoter may affect rRNA expression as an epigenetic regulatory mechanism. Oral squamous cell carcinoma (OSCC) is a kind of aggressive tumors which occurs in multiple sites in oral cavity. rRNA expression and the methylation of rDNA promoter in modulating rRNA expression in OSCC maintain unclear. This study aims to investigate the rRNA expression, the methylation status within rDNA promoter, and the underlying mechanism of methylation in regulating rRNA expression in OSCC.

Methods

Twelve primary OSCC and matched normal tissue samples were collected from patients with OSCC. Quantitative real‐time PCR was used to evaluate the rRNA level. HpaII/MspI digestion and bisulfite sequencing were used to investigate the methylation status of rDNA promoter.

Results

Ribosomal RNA levels were suppressed in OSCC as compared with matched normal tissues. HpaII/MspI digestion and bisulfite sequencing showed no significant differences for the methylation of rDNA promoter between the tumor and matched normal tissues.

Conclusion

The methylation in rDNA promoter could not explain for the suppressed rRNA expression in OSCC tissues.
Grading of hepatocellular carcinoma based on diffusion weighted images with multiple b‐values using convolutional neural networks
Authors: Zhou Wu , Wang Guangyi , Xie Guoxi , Zhang Lijuan
Published: June 2019

Purpose

To effectively grade hepatocellular carcinoma (HCC) based on deep features derived from diffusion weighted images (DWI) with multiple b‐values using convolutional neural networks (CNN).

Materials and Methods

Ninety‐eight subjects with 100 pathologically confirmed HCC lesions from July 2012 to October 2018 were included in this retrospective study, including 47 low‐grade and 53 high‐grade HCCs. DWI was performed for each subject with a 3.0T MR scanner in a breath‐hold routine with three b‐values (0,100, and 600 s/mm2). First, logarithmic transformation was performed on original DWI images to generate log maps (logb0, logb100, and logb600). Then, a resampling method was performed to extract multiple 2D axial planes of HCCs from the log map to increase the dataset for training. Subsequently, 2D CNN was used to extract deep features of the log map for HCCs. Finally, fusion of deep features derived from three b‐value log maps was conducted for HCC malignancy classification. Specifically, a deeply supervised loss function was devised to further improve the performance of lesion characterization. The data set was split into two parts: the training and validation set (60 HCCs) and the fixed test set (40 HCCs). Four‐fold cross validation with 10 repetitions was performed to assess the performance of deep features extracted from single b‐value images for HCC grading using the training and validation set. Receiver operating characteristic curve (ROC) and area under the curve (AUC) values were used to assess the characterization performance of the proposed deep feature fusion method to differentiate low‐grade and high‐grade in the fixed test set.

Results

The proposed fusion of deep features derived from logb0, logb100, and logb600 with deeply supervised loss function generated the highest accuracy for HCC grading (80%), thus outperforming the method of deep feature derived from the ADC map directly (72.5%), the original b0 (65%), b100 (68%), and b600 (70%) images. Furthermore, AUC values of the deep features of the ADC map, the deep feature fusion with concatenation, and the proposed deep feature fusion with deeply supervised loss function were 0.73, 0.78, and 0.83, respectively.

Conclusion

The proposed fusion of deep features derived from the logarithm of the three b‐value images yields high performance for HCC grading, thus providing a promising approach for the assessment of DWI in lesion characterization.
Efficient silicon nitride SiNx:H antireflective and passivation layers deposited by atmospheric pressure PECVD for silicon solar cells
Authors: Lelièvre Jean‐François , Kafle Bishal , Saint‐Cast Pierre , Brunet Paul , Magnan Romain , Hernandez Emmanuel , Pouliquen Sylvain , Massines Françoise
Published: June 2019

This work demonstrates the efficient optical and passivation properties provided by hydrogenated silicon nitride (SiNx:H) layers deposited in a lab‐scale atmospheric pressure plasma enhanced chemical vapor deposition (AP‐PECVD) reactor. By applying modulated low‐frequency plasma (200 kHz), homogeneous SiNx:H layers, with small variances in thickness w and refractive index n (Δw ≤ 2 nm; Δn ≤ 0.02), were achieved on a surface area of 45 × 55 mm2. The use of voltage amplitude modulation enabled discharge optimization and led to greatly enhanced SiNx:H film homogeneity and conformity in comparison with continuous plasma discharge conditions. Additionally, AP‐PECVD SiNx:H showed good thermal stability (Δw ≤ 1 nm; Δn ≤ −0.02) with low absorption coefficients (k ≤ 0.1 at 275 nm), demonstrating that such layers could act as efficient antireflective coatings. Furthermore, outstanding surface passivation properties were achieved after firing, both on n‐type FZ c‐Si substrates of standard 2.8 Ω.cm doping (τeff = 1.45 ms) and on highly doped 85 Ω/sq n+ emitters (j0e = 74 ± 2 fA.cm−2). Finally, AP‐PECVD SiNx:H thin films were tested on industrial passivated emitter and rear solar cell (PERC) architectures, where the potential of applying these layers both as efficient rear‐side capping layer and front‐side antireflective coating was demonstrated. The first lab‐scale 40 × 40 mm2 PERC solar cells featuring AP‐PECVD SiNx:H layers led to conversion efficiencies of up to 20.6%. These results pave the way for upscaling the dielectric barrier discharge lab‐scale reactor in an industrial in‐line process, which could provide low‐cost and high‐throughput SiNx:H capping and antireflective layers.
Radiofrequency Ablation for Posterior Sacroiliac Joint Complex Pain: A Narrative Review
Authors: Yang Aaron J. , McCormick Zachary L. , Zheng Patricia Z. , Schneider Byron J.
Published: June 2019

Radiofrequency ablation (RFA) of the sacral lateral branches targets the innervation of the posterior sacroiliac ligaments and posterior portion of the sacroiliac joint, also referred to as the posterior sacroiliac joint complex. This review assesses the published evidence on local anesthetic blocks for the diagnosis of posterior sacroiliac joint complex pain and the efficacy of RFA of the sacral lateral branches as a treatment. The current evidence suggests that RFA can provide relief of pain that originates from the posterior sacroiliac joint complex, but interpretation of this literature is limited by variability in patient selection criteria, the specific nerves targeted for ablation, and the types of RFA technology and technique utilized.
Modeling conformational flexibility of kinases in inactive states
Authors: Schwarz Dominik , Merget Benjamin , Deane Charlotte , Fulle Simone
Published: June 2019

Kinase structures in the inactive “DFG‐out” state provide a wealth of druggable binding site variants. The conformational plasticity of this state can be mainly described by different conformations of binding site‐forming elements such as DFG motif, A‐loop, P‐loop, and αC‐helix. Compared to DFG‐in structures, DFG‐out structures are largely underrepresented in the Protein Data Bank (PDB). Thus, structure‐based drug design efforts for DFG‐out inhibitors may benefit from an efficient approach to generate an ensemble of DFG‐out structures. Accordingly, the presented modeling pipeline systematically generates homology models of kinases in several DFG‐out conformations based on a sophisticated creation of template structures that represent the major states of the flexible structural elements. Eighteen template classes were initially selected from all available kinase structures in the PDB and subsequently employed for modeling the entire kinome in different DFG‐out variants by fusing individual structural elements to multiple chimeric template structures. Molecular dynamics simulations revealed that conformational transitions between the different DFG‐out states generally do not occur within trajectories of a few hundred nanoseconds length. This underlines the benefits of the presented homology modeling pipeline to generate relevant conformations of “DFG‐out” kinase structures for subsequent in silico screening or binding site analysis studies.
Features of the Formation of the BiBs Defect in Si
Authors: Khirunenko Lyudmila , Sosnin Mikhail , Duvanskii Andrei , Abrosimov Nikolay , Riemann Helge
Published: June 2019

The data on the features of the electronic absorption in boron‐doped silicon irradiated at 80 K with 5 MeV electrons are presented in this paper. The electronic transition at a frequency of 4296.8 cm–1 is revealed in the absorption spectra of as‐irradiated boron‐doped Si samples. The intensity of the registered line grows with the boron concentration. The formation of defect responsible for the 4296.8 cm–1 line is independent of the presence of oxygen and carbon in the samples. The investigations show that the vacancies are not components of the defect related to the 4296.8 cm–1 line. The study of the thermal stability of the revealed defect shows that the disappearance of line at the annealing is accompanied by the synchronous development of the 4385.2 cm–1 absorption line associated with the BiBs defects. The revealed defect is identified as a precursor of a stable configuration of the BiBs complex.
A High‐Performance and Low‐Cost Ethanol Vapor Sensor Based on a TiS2/PVP Composite
Authors: Hosseini‐Shokouh Seyed Hossein , Fardindoost Somayeh , Zad Azam Iraji
Published: June 2019

Low‐cost ethanol vapor sensors are fabricated by electrospinning of TiS2/PVP fibers on pre‐patterned metal electrodes. TiS2 ribbons have been synthesized through sulfuration of titanium (Ti) foil using chemical vapor transport (CVT). We found selective and stable responses at a low concentration of ethanol vapor (2 ppm) at room temperature with the transient response and recovery times experimentally around 60 s and 2 s respectively. The relatively high responses of sensors (6800% at 18 ppm) are attributable to the synergy effect of TiS2/PVP composite structure. The mechanism of sensing is discussed based on proton hopping while the sensors exposed to ethanol vapor.
An Investigation on the Effect of Li–Ion Cycling on the Vertically Aligned Brookite TiO2 Nanostructure
Authors: Kitchamsetti Narasimharao , Kalubarme Ramchandra S. , Chikate Parameshwar R. , Park Chan‐Jin , Ma Yuan‐Ron , Shirage Parashram M. , Devan Rupesh S.
Published: June 2019

We reported the investigation on the effect of Li‐ion cycling on the vertically aligned brookite (β) TiO2 nanorods coated on Cu substrate as a Li‐ion battery electrode. The vertically grown β‐TiO2 nanorods synthesized over large area array using hot filament metal vapor deposition (HFMVD) technique were ∼19 nm in diameter with well‐defined textural boundaries. X‐ray photoelectron spectroscopy revealed the formation of stoichiometric β‐TiO2 nanorods and Raman spectroscopy revealed the formation of pure brookite phase, and not accompanied by the anatase and/or rutile phases. The β‐TiO2 nanorods showed good electrochemical performance with the appearance of the potential plateau at 1.8 and 2.1 V during Li insertion and desertion. The initial discharge/charge capacities of ∼81 (52 μAh cm−2 μm−1) and ∼72 mAhg−1 (45 μAh cm−2 μm−1) obtained at the current density of 33 mAg−1 were retained further to ∼62 mAhg−1 (40 μAh cm−2 μm−1) until the 200th cycle. The exceptional cycling performance of β‐TiO2 nanorods with a high coulombic efficiency of greater than ∼98% confirms their potentials as a competent electrode for Li‐ion rechargeable batteries.
Biological Oxidase Enzyme Mimetic Cu‐Pt Nanoalloys: A Multifunctional Nanozyme for Colorimetric Detection of Ascorbic Acid and Identification of Mammalian Cells
Authors: Shah Maitri , Shah Juhi , Arya Homica , Vyas Aashna , Vijapura Akdasbanu , Gajipara Akhil , Shamal Anmol , Bakshi Malvika , Thakore Prachi , Shah Rutvi , Saxena Vijaylaxmi , Varade Dharmesh , Singh Sanjay
Published: June 2019

Nanomaterials serving as artificial enzymes of the new generation (nanozymes), exhibit enhanced catalytic performance, excellent stability, low cost of production, and other associated properties of nanoparticles. This emerging field of nanozymes has broad‐spectrum potential applications in the bridging area nanotechnology and biomedicine. Among metal‐based nanozymes, bimetallic nanoparticles have been found to show enhanced catalytic performance and display ability to catalyze multistep reactions typically not observed in their monometallic counterparts. Herein, we report the synthesis of Cu−Pt based bimetallic nanoalloys coated with a nonionic surfactant polyoxyethylene cholesteryl ether. The characterization data suggest that the developed nanoalloys have an almost uniform distribution of Cu and Pt (1:1) elements; therefore, this novel technique could be used for the large‐scale synthesis of Cu−Pt based nanozymes in a one‐step procedure. Further investigations showed that these bimetallic nanoalloys possess excellent biological oxidase enzyme‐like activity and the catalytic activity could be performed at harsh conditions of pH and temperature. Oxidase activity of Cu−Pt nanoalloys was utilized for the sensitive detection of ascorbic acid in the sub‐micromolar concentration range. Supplementing ATP in the oxidase reaction, the nanozyme showed enhanced catalytic activity, which was used for the detection of human liver cells.
Preparation of Ethyl Cellulose Composite Film with Down Conversion Luminescence Properties by Doping Perovskite Quantum Dots
Authors: Zhao Xiaoyu , Yan Guihua , Sun Yong , Tang Xing , Zeng Xianhai , Lin Lu , Lei Tingzhou
Published: June 2019

The preparation and characterization of a perovskite quantum dot‐ethyl cellulose (PQD‐EC) composite film are described. The toluene suspension of perovskite quantum dots (PQDs) was injected into the ethyl cellulose (EC) toluene solution to form the transparent solution. Then the composite film was prepared by solvent casting method. The composite film had the characteristics of high optical transmittance and excellent down conversion luminescent. When excited by ultraviolet (UV) 365 nm, it exhibited bright green emission centered at 518 nm. The analyses showed that the composite film exhibited excellent thermodynamic and mechanical properties similar to the pure EC film. Further, the sandwich‐like multilayer films was prepared by encapsulating the PQDs‐EC composite film with pure EC films to overcome the defect of PQDs susceptible to water. When used as coating film for solar cell, the composite film obtained an observable enhancement in the photoelectric conversion efficiency.
Highly Efficient CuCo2O4 Decorated Er0.4Bi1.6O3 Nanostructured Cathode for Intermediate Temperature Solid Oxide Fuel Cells
Authors: Kong Yu , Sun Chengzhi , Wu Xian , Zhang Yu , Zhang Naiqing , Sun Kening
Published: June 2019

The cathode efficiency for intermediate temperature solid oxide fuel cells is largely limited by the catalytic activity for oxygen reduction reaction. Here by, we design and synthesize CuCo2O4 decorated Er0.4Bi1.6O3 cathode by means of a simple gelation method and then screen‐print it on scandium‐stabilized zirconia electrolyte cell followed by a relatively lower temperature sintering process. The decoration of CuCo2O4 adequately enhances the electro‐catalytic activity of the composite cathode for the ORR. In addition, Er0.4Bi1.6O3 matrix also reduces the sintering temperature (from 1000 °C to 850 °C) compared to the pristine CuCo2O4 electrode. The CuCo2O4‐decorated‐Er0.4Bi1.6O3 composite cathode demonstrates a lower polarization resistance (0.016 Ω cm2 at 800 °C) in air, exhibiting an 87% decrease in comparison to the primary CuCo2O4 cathode.
Unsupported Nanoporous Gold‐Catalyzed Chemoselective Reduction of Quinolines Using Formic Acid as a Hydrogen Source
Authors: Butt Madiha , Zhao Yuhui , Feng Xiujuan , Lu Ye , Jin Tienan , Yamamoto Yoshinori , Bao Ming
Published: June 2019

The unsupported nanoporous gold (AuNPore) is demonstrated to be an active and stable heterogeneous catalyst for chemoselective transfer hydrogenation of quinolines using bio‐renewable formic acid (HCO2H) as hydrogen source. The AuNPore‐catalyzed transfer hydrogenation of quinolines proceeded smoothly in the presence of low amounts of HCO2H at a relatively low temperature to produce the desired 1,2,3,4‐tetrahydroquinolines (py‐THQs) in good to excellent yields. Mechanistic studies revealed that the AuNPore‐catalyzed transfer hydrogenation of quinolines proceeded through a sequence of 1,4‐hydride addition, isomerization, and 1,2‐hydride addition. This operationally simple protocol offers a practical alternative to the currently known methods for chemoselective quinoline reduction.
Urea‐Catalysed Access to Novel Spirooxindole Benzopyrans via Domino Multicomponent Cascade: Approach Towards Sustainability
Authors: Bagchi Sourav , Shube Hussen Abdulkadir , Deeksha  , Sharma Anuj
Published: June 2019

A multicomponent one‐pot domino reaction of 1‐hydroxy‐3H‐benzo[f]chromen‐3‐one, isatin and malononitrile/ethyl cyanoacetate is herein investigated. The methodology concludes to synthesize diversified novel spiro‐benzo[f]pyranochromene derivatives in good to excellent yields. This method is compatible with different unsubstituted and substituted isatins bearing electron‐donating and electron‐withdrawing groups. The operational simplicity, short reaction time along with the gram scale up protocol make this synthetic process suitable for both academia as well as industry.
Facile Scalable Synthesis of Carbon‐Coated Ge@C and GeX@C (X=S, Se) Anodes for High Performance Lithium‐Ion Batteries
Authors: Wang Miao , Zheng Hui , Zhan Wenqi , Luo Qinxin , Tang Kaibin
Published: June 2019

Amorphous germanium@C and germanium chalcogenides@C composites have been fabricated via a simply developed synthetic route. Taking advantage of the carbon coating of these materials, they all exhibit excellent Li storage properties as anode materials for lithium ion batteries (LIBs). Typically, Ge@C presents a capacity of 672 mAh g−1 after 80 cycles at current density of 0.5 A g−1. The capacities of GeS@C are about 604 mAh g−1 over 180 cycles at 0.2 A g−1 and 365 mAh g−1 at 0.5 A g−1 after 1000 cycles, respectively. As for GeSe@C electrode, it exhibit high capacities of nearly 780 mAh g−1 at 0.2 A g−1 over 180 cycles and 562 mAh g−1 at 0.5 A g−1 over 60 cycles.
Two‐Photon Vertical‐Flow Lithography for Microtube Synthesis
Authors: Lölsberg Jonas , Cinar Arne , Felder Daniel , Linz Georg , Djeljadini Suzana , Wessling Matthias
Published: June 2019

Two‐photon vertical‐flow lithography is demonstrated for synthesis of complex‐shaped polymeric microtubes with a high aspect ratio (>100:1). This unique microfluidic approach provides rigorous control over the morphology and surface topology to generate thin‐walled (<1 µm) microtubes with a tunable diameter (1–400 µm) and pore size (1–20 µm). The interplay between fluid‐flow control and two‐photon lithography presents a generic high‐resolution method that will substantially contribute toward the future development of biocompatible scaffolds, stents, needles, nerve guides, membranes, and beyond.
General Approach to Produce Nanostructured Binary Transition Metal Selenides as High‐Performance Sodium Ion Battery Anodes
Authors: Ali Zeeshan , Asif Muhammad , Zhang Teng , Huang Xiaoxiao , Hou Yanglong
Published: June 2019

Multiple transition metals containing chalcogenides have recently drawn boosted attraction as anodes for sodium ion batteries (SIBs). Their greatly enhanced electrochemical performances can be attributed to the superior intrinsic conductivities and richer redox reactions, comparative to mono metal chalcogenides. To employ various binary metals comprising selenides (B‐TMSs) for SIBs, discovery of a simplistic, scalable and universal synthesis approach is highly desirable. Herein, a simple, facile, and comprehensive strategy to produce various combinations of nanostructured B‐TMSs is presented. As a proof of concept, optimized, high surface area bearing, and hierarchical nanosheets of iron–nickel selenide (FNSe), iron–cobalt selenide, and nickel–cobalt selenide are produced and employed in SIBs. These B‐TMSs exhibit adequately high energy capacities, excellent rate capabilities, and an extraordinarily stable life of 2600 cycles. As far as it is known, it is the first work to discuss sodium storage of FNSe, so various in situ and ex situ battery analyses are carried out to probe the sodium storage mechanism. When employed in sodium full batteries, these B‐TMSs present reasonably high reversible specific capacities even after 100 cycles. Overall, the presented strategy will pave the way for facile synthesis of numerous binary transition metal chalcogenides that are the potential materials for energy storage and conversion systems.
Crime Watch: Hurricanes and Illegal Activities
Authors: Spencer Nekeisha , Strobl Eric
Published: June 2019

We investigate the relationship between hurricane strikes and crime for Jamaica. To this end, we construct hurricane damages and daily recorded criminal activity. Hurricanes are found to significantly increase crime by 35%, where the impact is stronger for more damaging storms, but this only lasts for the duration of the storm. Decomposing crime into its various subtypes, one finds that while aggravated assault, break‐ins, and shooting increase during a hurricane, murders, rapes, and robberies actually decline. The greatest increase is with shootings, whereas the greatest decline is with rape. Crucially, the impact of crime depends on the existence of a storm warning. Our results also show that high frequency data more accurately estimate the impact of hurricanes on crime.
Industrial Opportunities and Challenges for Perovskite Photovoltaic Technology
Authors: Wojciechowski Konrad , Forgács Dávid , Rivera Thomas
Published: June 2019

Perovskite solar cell technology is fast approaching its first commercial deployment, with the 10‐year mark since the first research having passed recently. Commercial entrance seems very tangible, but there are a number of remaining challenges related to various economic and technical factors. Conventional photovoltaic markets, such as utility scale photovoltaics, are quite rigid and very demanding for a new entrant. Perovskites offer several new value propositions, which offer monetization prospects in the near future, if properly used. In particular, functionalities such as flexibility, high specific power, and good low‐light performance enable new applications and broadening of the conventional PV usage. The specific cases of internet of things and building‐integrated photovoltaics are discussed, and market opportunities are analyzed. Technology incubation with simultaneous market presence in emerging applications can provide essential economic stability and time for the technology to develop into its full potential. Opportunities in high‐value markets and massive‐scale deployment are also addressed, with the analysis of potentially disruptive offerings being promised by perovskite photovoltaic technology.
Effects of soil‐structure interaction and lateral design load pattern on performance‐based plastic design of steel moment resisting frames
Authors: Ganjavi Behnoud , Gholamrezatabar Abolfazl , Hajirasouliha Iman
Published: June 2019

The effects soil‐structure interaction (SSI) and lateral design load‐pattern are investigated on the seismic response of steel moment‐resisting frames (SMRFs) designed with a performance‐based plastic design (PBPD) method through a comprehensive analytical study on a series of 4‐, 8‐, 12‐, 14‐, and 16‐story models. The cone model is adopted to simulate SSI effects. A set of 20 strong earthquake records are used to examine the effects of different design parameters including fundamental period, design load‐pattern, target ductility, and base flexibility. It is shown that the lateral design load pattern can considerably affect the inelastic strength demands of SSI systems. The best design load patterns are then identified for the selected frames. Although SSI effects are usually ignored in the design of conventional structures, the results indicate that SSI can considerably influence the seismic performance of SMRFs. By increasing the base flexibility, the ductility demand in lower story levels decreases and the maximum demand shifts to the higher stories. The strength reduction factor of SMRFs also reduces by increasing the SSI effects, which implies the fixed‐base assumption may lead to underestimated designs for SSI systems. To address this issue, new ductility‐dependent strength reduction factors are proposed for multistory SMRFs with flexible base conditions.
Parametric study of the use and optimization of tuned mass dampers to control the wind‐ and seismic‐induced responses of a slender monument
Authors: Pozos‐Estrada Adrián , Gómez Roberto
Published: June 2019

Passive energy dissipation devices have been used around the world to mitigate the response of structures under dynamic excitations, such as wind or seismic loading. The use of tuned mass dampers (TMD) in tall and slender buildings to reduce unwanted responses has proved to be very effective. The main purpose of this work is to study the structural behavior of a 115‐m‐height slender monument fitted with TMDs subjected to simulated wind and seismic loading. Turbulent wind forces were calculated based on samples of turbulent wind speed simulated with an auto regressive and moving average (ARMA) model. Ground motions compatible with a seismic site spectrum were also simulated. An optimization approach is suggested to determine the parameters of the TMDs that reduce the structural response to the maximum. The effectiveness of the TMDs for reducing the structural response of the monument is discussed in detail, and the use of optimally tuned TMDs is emphasized.
The Impact of Potential Korea-U.S. Free Trade Agreement Renegotiation on the Korean Rice Market and Trade
Authors: Soon Byung Min , Westhoff Patrick , Thompson Wyatt
Published: June 2019

Korea replaced its rice import quota with a tariff rate quota (TRQ) in 2015. A structural model representing the Korean rice market is developed to evaluate this new trade policy and examine the possibility of Korean rice imports under uncertainty. Results indicate that rice imports in excess of the current TRQ quantity are unlikely for a range of market conditions. Two scenarios, which are the over-quota tariff rate reduction and the TRQ quantity expansion, show how the market responds to policy changes. In addition, Korean rice imports are sensitive to consumer preferences for different rice types.
Rapid multi-layer method on solving optimal endo-atmospheric trajectory of launch vehicles
Authors: Wei Changzhu , Han Yepeng , Pu Jialun , Li Yuan , Huang Panxing
Published: June 2019

In order to increase the speed, precision and robustness against the engine failure in solving optimal endo-atmospheric ascent trajectory of a launch vehicle, a rapid multi-layer solving method with improved numerical algorithms was proposed. The proposed method is capable of decomposing a large number of intervals into multiple layers with advantageous convergence property. Firstly, the problem of solving optimal endo-atmospheric ascent trajectory, which was subjected to path constraints and terminal constraints, was transformed into a Hamilton Two Point Boundary Value Problem (TPBVP). Then, through the finite difference method and numerical solving algorithm, the Hamilton TPBVP was iteratively solved with fewer initial discrete intervals. The initial values of higher-layer iterations were obtained by interpolating convergent solutions at sparse nodes into the doubly discrete nodes of high layers. The process was repeatedly performed until the solving precision met the requirements. To decrease the calculation load in solving TPBVPs, two improved solving algorithms without and with fewer Jacobian calculations were studied, respectively the Derivative-free Spectral Algorithm for Nonlinear Equations(DF-SANE) combined with the improved derivative-free nonmonotone line search strategy, and the Modified Newton method with a relaxation factor in combination with the Inverse Broyden Quasi-Newton method, denoted as ‘MN-IBQ’. Simulation verifications showed that the multi-layer method had significantly higher solving speed than the single-layer method. For the improved numerical algorithms, the DF-SANE was trapped in the local convergence problem. While using the proposed MN-IBQ can further increase the solving rate. Typical engine failure simulations showed that the multi-layer method with the MN-IBQ algorithm had not only significantly higher solving speed but also stronger robustness, where the traditional single-layer method could not adapt. In addition, the thrust loss tolerance limits for the multi-layer solving method were given for different engine failure times. The results show promising potential of the proposed approach in trajectory online generation and closed-loop guidance of launch vehicles at the endo-atmospheric ascent stage.
Use of Predictive Modeling to Plan for Special Event Medical Care During Mass Gathering Events
Authors: Allgaier Rachel L. , Shaafi-Kabiri Nina , Romney Carla A. , Wallis Lee A. , Burke John Joseph , Bhangu Jaspreet , Thomas Kevin C.
Published: June 2019

Objectives:

In 2010, South Africa (SA) hosted the Fédération Internationale de Football Association (FIFA) World Cup (soccer). Emergency Medical Services (EMS) used the SA mass gathering medicine (MGM) resource model to predict resource allocation. This study analyzed data from the World Cup and compared them with the resource allocation predicted by the SA mass gathering model.

Methods:

Prospectively, data were collected from patient contacts at 9 venues across the Western Cape province of South Africa. Required resources were based on the number of patients seeking basic life support (BLS), intermediate life support (ILS), and advanced life support (ALS). Overall patient presentation rates (PPRs) and transport to hospital rates (TTHRs) were also calculated.

Results:

BLS services were required for 78.4% (n = 1279) of patients and were consistently overestimated using the SA mass gathering model. ILS services were required for 14.0% (n = 228), and ALS services were required for 3.1% (n = 51) of patients. Both ILS and ALS services, and TTHR were underestimated at smaller venues.

Conclusions:

The MGM predictive model overestimated BLS requirements and inconsistently predicted ILS and ALS requirements. MGM resource models, which are heavily based on predicted attendance levels, have inherent limitations, which may be improved by using research-based outcomes.
THE FLUTED FRAGMENT REVISITED
Authors: PRATT-HARTMANN IAN , SZWAST WIESŁAW , TENDERA LIDIA
Published: June 2019

We study the fluted fragment, a decidable fragment of first-order logic with an unbounded number of variables, motivated by the work of W. V. Quine. We show that the satisfiability problem for this fragment has nonelementary complexity, thus refuting an earlier published claim by W. C. Purdy that it is in NExpTime. More precisely, we consider ${\cal F}{{\cal L}^m}$, the intersection of the fluted fragment and the m-variable fragment of first-order logic, for all $m \ge 1$. We show that, for $m \ge 2$, this subfragment forces $\left\lfloor {m/2} \right\rfloor$-tuply exponentially large models, and that its satisfiability problem is $\left\lfloor {m/2} \right\rfloor$-NExpTime-hard. We further establish that, for $m \ge 3$, any satisfiable ${\cal F}{{\cal L}^m}$-formula has a model of at most ($m - 2$)-tuply exponential size, whence the satisfiability (= finite satisfiability) problem for this fragment is in ($m - 2$)-NExpTime. Together with other, known, complexity results, this provides tight complexity bounds for ${\cal F}{{\cal L}^m}$ for all $m \le 4$.
Teaching proofs without words using dynamic geometry
Authors: Stupel Moshe , Sigler Avi , Jahangiri Jay
Published: June 2019

A Proof Without Words (PWW) contains data, the claim that is to be proved, and one or more diagrams, sometimes without anything else and in other cases with a few mathematical expressions, without any verbal justifications [1]. It is assumed that students and researchers who possess the related appropriate mathematical knowledge will view the drawings and the expressions, will be able to follow and justify each step in the proof and develop their own visual proof abilities. PWW is very much like a cartoon which contains a drawing with sometimes only a few words or sometimes no words at all and the observers are expected to understand the context or the projected message.
A hyperbolic proportionality theorem and hyperbolic surveying problems
Authors: Lamphere Robert L
Published: June 2019

A surveyor often encounters problems like

Problem 1:

Determine the length of side AC of the right triangle ABC with the right angle at B. A lake intersecting the sides AC and CE prevents the direct measurement of their sides.
The three Steiner-Lehmus theorems
Authors: Beardon A. F.
Published: June 2019

Steiner’s proof of what is now called the Steiner-Lehmus theorem was published in 1844, the same year as the book The three musketeers, written by the French author Alexandre Dumas. The motto One for all, all for one (Einer für alle, alle für einen; Un pour tous, tous pour un; Uno per tutti, tutti per uno) of the three musketeers came into widespread use in Europe in the 19th century, and its essence is that the three musketeers are inseparable; each member pledges to support the group, and the group supports each member. Now there are three classical geometries of constant curvature, namely Euclidean, spherical and hyperbolic geometries, and one can argue that, like the three musketeers, these geometries should be considered as being inseparable; that is, an idea, theorem or proof in any one of them should automatically be considered in the other two. The issue here should be not only to decide whether a particular result is true, or false, in a given geometry, but to understand which particular properties of the geometries make it so.
Annually Verified Growth of Cedrela Fissilis from Central Brazil
Authors: Hammerschlag Izabela , Macario Kita D , Barbosa Ana Carolina , Pereira Gabriel de Assis , Farrapo Camila Laís , Cruz Francisco
Published: June 2019

Given the difficulty in obtaining robust chronologies from tree rings in tropical regions, the search for appropriate species is very important. Both dendrochronology and radiocarbon (14C) measurements are required to validate the use of any specific tree. Some species have proved to be reliable for representing atmospheric 14C concentration over time, such as Cedrela fissilis and Araucaria angustifolia. However, not only the species have to be validated, but also different climatic conditions may result in different growth patterns for the same species. In this work, we study the annual growth rings of Cedrela fissilis from a dry tropical forest patch typical of a highly seasonal climate in central Brazil. 14C accelerator mass spectrometry (AMS) was used to compare the isotopic ratios of tree rings with the 14C concentrations in the atmosphere during the nuclear tests based on curve Bomb13SH 1-2. Results are similar to the bomb peak curve within the period from 1958 to 1980 AD and serve as a crucial test for the cross-dating analyses using the skeleton plot technique.
A Preliminary ion Source Background Study at Lalonde AMS
Authors: Zhao X-L , Crann C A , Murseli S , St-Jean G , Kieser W E , Wilk M , Cornett R J , Clark I D
Published: June 2019

Observation of the ion source generated background has been an area of focus during our routine analytical work. It is noted that the results of very-low-ratio samples are dependent upon the particular procedures for measurement using the present-day Cs+ sputter ion sources. When measured without excessive Cs+ fluxes and without interleafing with other higher-ratio samples and references, the accelerator mass spectrometry (AMS) sensitivity can be somewhat improved. In some cases, it appears possible to assess old radiocarbon (14C) samples to beyond the long-standing 60 kyr limit. A number of observational studies are made for the sole purpose of minimizing the final contamination to the rare isotopes that is generated within the ion source.
Observational Constraints on the Structure of the Pulsar Magnetic Field
Authors: Kuz'min A. D.
Published: June 2019

The most widely adopted model of pulsar radio emission is the hollow cone model, which fits much of the experimental data. The pulsar radio emission in this model is curvature radiation of relativistic particles flowing from the magnetic poles of the neutron star along a cone of open magnetic lines. The curvature radiation is amplified at the plasma frequency, therefore different radio frequencies f originate at different radii r of the emitting regions.
New Observations of the Time Alignment of Pulse Profiles at High and Low Frequencies
Authors: Izvekova V. A. , Kuz'min A. D. , Malofeev V. M. , Sieber W. , Jessner A. , Wielebinski R.
Published: June 2019

Exact timing measurements allow a determination of the phase shift between observations of a pulsar at different frequencies. It has become clear from these observations that a simple dipole magnetic field configuration can not explain the time lag observed for many pulsars between profiles at high frequencies (Kuz'min et al. 1986).

There are cases which might better be explained by a combination of dipole and quadrupole field components (Davies et al. 1984). We report in this paper on new pulsar time alignment observations of a number of pulsars at high and low frequencies which support the general picture outlined above.
On the Angles Between the Magnetic and Rotation Axes
Authors: I. F. Malov
Published: June 2019

Several methods for evaluating the angle β between the magnetic moment and rotation axis of a pulsar are considered. Averaged values of this angle, estimated by different methods for 61 pulsars, decrease as the characteristic age increases. Many pulsars have small angles = 23°) and large ages ((log т) = 7.0), so the alignment of the magnetic and rotation axes must take place during the evolution of pulsars.
Global Structure of An Axially Symmetric Pulsar Magnetosphere
Authors: Rylov Yu. A.
Published: June 2019

A self-consistent model of the pulsar magnetosphere is presented. The principal point of the model is its use of the massless approximation. In this approximation electrons and positrons are considered as massless particles, and the pulsar magnetosphere consists of regions of two types: (1) accelerating regions (A-regions) filled with particles moving with the speed of light [dynamical phase (DP)], (2) capture regions (C-regions) which, besides the DP, contain static phase (SP), i.e. captured particles resting at some coordinate system.
Collective Electron-Positron Annihilation
Authors: Belyanin A. A. , Kocharovskii V. V. , Kocharovskii Vl. V.
Published: June 2019

The phenomenon of collective spontaneous annihilation of a magnetized electron-positron plasma is predicted. Like the superradiance in systems with discrete energy spectra, collective annihilation leads to the generation of powerful coherent radiation with the rate of this process considerably exceeding the spontaneous annihilation and collisional relaxation rates.
Linear Acceleration Emission: A Detailed Analysis
Authors: Rowe E. T.
Published: June 2019

An exact expression is given for the orbit of a charged particle accelerated by a non-propagating electrostatic wave. The corresponding current is obtained, for untrapped particles, as an expansion in Bessel functions, and a Lorentz transform allows us to treat the case of a propagating wave. An appropriate form for the absorption coefficient is derived, and an interesting angular and frequency dependence is revealed when the propagating wave is superluminal. Finally, the possible application to pulsars, particularly in explaining the multicomponent pulse profiles, is discussed briefly.
Are millisecond pulsars different than “Normal” pulsars?
Authors: Manchester R. N.
Published: June 2019

While millisecond pulsars have very different period parameters and a different evolutionary history compared to “normal” pulsars, the properties of their pulsed emission are remarkably similar to those of normal pulsars.
Detecting UV Radiation from Nearby Pulsars with the Hubble Space Telescope
Authors: Pavlov George G.
Published: June 2019

Even old (106 to 107 yr) pulsars within a few hundred parsecs of the Sun should give UV and optical fluxes via thermal radiation or radiation from relativistic particles. The surface temperature of a neutron star depends on its mass, radius, magnetic field, and internal composition (existence of pion condensate, superfluidity of nuclÃ©ons, etc.). If the temperature exceeds ~2x104 K, the thermal radiation can be detected by the Hubble Space Telescope. An analysis of the results will allow one to study the thermal evolution and inner structure of neutron stars in order to obtain additional constraints on pulsar models.
Shall we Observe a Radio Binary Pulsar in SN 1987A?
Authors: G. J. Qiao
Published: June 2019

An induced-collapse model [hereafter IC model; He et al. (1990)] can overcome the problems of the single star model of SN1987A. According to the IC model, there is a possibility that the SN1987A remnant will be a binary system with two neutron stars, one of them (SK-69 202) will have a strong magnetic field and a high surface temperature which favors detection as an X-ray or γ-ray pulsar. If the surface temperature of the neutron star cools down to T = 107 K, a radio binary pulsar is expected. There is also the possibility that an X-ray or γ-ray pulsar will be observed first, and only later will a radio pulsar will be detected.

A newly formed neutron star is thought to have a short (millisecond) period. In this case, the core emission beam is then very large (Qiao 1992) and is thus very likely to swing in the direction of the Earth.
General Relativistic Electrodynamics of the Magnetic Polar Regions of Neutron Stars
Authors: Muslimov A. G. , Tsygan A. I.
Published: June 2019

The induction of the electric fields near a rotating neutron star is considered within the framework of General Relativity. It is demonstrated that within the open magnetic field region, filled by relativistically moving charged particles, a sufficiently strong component of the electric field is generated. This component is due to the effect of dragging of inertial frames of reference and predominates in the case when a neutron star is not exactly an orthogonal rotator. Finally, we discuss some implications of our results on the theory of radio pulsars.
Single-Pulse Intensity Fluctuations by Cross-Correlation with Longitude of the Average Profile
Authors: POPOV M.V. , Sieber W.
Published: June 2019

Single-pulse radio emission from pulsars has been observed to vary both in intensity and position inside the pulse window. In some cases the variations show a rather regular structure (drifting subpulses). Such a regular structure can clearly be studied by fluctuation spectral analysis. The analysis has identified some particular peculiarities in the fluctuation spectra at different longitudes of the pulse window in many pulsars (Backer 1973, Page 1973, Popov and Smirnova 1982). In pulsars with complex integrated profiles (PSR 1919+21, PSR 1237+25) narrow features in the fluctuation spectra vary strongly with longitude, at some longitudes being quite undistinguishable.
Four Pulsars with New Faces
Authors: Nowakowski Leszek A.
Published: June 2019

This paper presents results on four radio pulsars observed at Arecibo. Three pulsars have been discovered as new mode switching pulsars. In two of them the switching effect is correlated with a dramatic change of the amplitude of the core component, suggesting that the change occurs not only in the location of the emission region, but also in the efficiency of the emission mechanism. In another pulsar evidence is presented for the existence of a third (possibly a core) component which is hidden between the two conal components of the average profile. Previously unknown drifting subpulses and at least two new components have been found in one of the three mode switching pulsars.
Resolution of the PSR 1919+21 Magnetosphere Emitting Region
Authors: Kuz'min O. A.
Published: June 2019

Regular structure with 10 to 50kHz-scale was detected in the radio scintillation spectrum of PSR 1919+21. This regular structure may be a simple interferometric pattern formed by refractive multi-ray propagation between the pulsar and observer. It was found that the pulsar PSR 1919+21 radio emission scintillation spectrum phase changes significantly across the average profile. Within the refractive scattering scenario this phase-longitude dependence corresponds to a transversal shift of the magnetosphere emitting region of about 6 x 108 cm. The radio emission altitude is estimated to be near the light cylinder.
Deterministic Chaos in the Microstructure of Radio Pulses of PSR 0809+74
Authors: Zhuravlev V. I. , Popov M. V.
Published: June 2019

480 single pulses from PSR 0809+74, recorded at 102.5 MHz with a time resolution of 10μs, have been analyzed by the time delay technique in order to look for the parameters of deterministic chaos in the microstructure of radio pulses. The correlation dimension n was shown to be less than 5 in more than 20% of the analyzed pulses. This means that on such occasions the microstructure of pulsar radio emission with the time scales 10 to 100μs may be determined by the behavior of a nonlinear dynamical system with comparatively small numbers of independent parameters. For example, the observed low dimensional chaos may result from a turbulence process associated with the outflow of plasma—as in versions of the polar cap model where microstructure can be interpreted as reflecting the spatial structure of relativistic plasma outflow in the radio emission region.

However, the correlation-time distribution demonstrates the tendency for microstructure to consist of a random sequence of unresolved micropulses in the majority of cases, which means in the framework of polar cap models the presence of well developed turbulence in the relativistic plasma outflow.
Closing Comments: Observations
Authors: Sieber W.
Published: June 2019

Many of the problems discussed at this conference were also on the agenda of the Bonn symposium on pulsars (IAU 95) about ten years ago, and it seems worthwhile to compare how our view of the magnetosphexe and pulsar emission has changed since then.
A Fourteenth-Century Pulpitum Screen at Tintern Abbey, Monmouthshire
Authors: Harrison Stuart A. , Morris Richard K. , Robinson David M.
Published: June 2019

Tintern is one of the best-known monastic sites in the British Isles, even if its architectural history is less well understood than assertions in the general literature might suggest. This study focusses upon a distinct group of ex situ masonry fragments until recently dispersed across the site. As reconstructed on paper, the material represents the remarkable ‘rediscovery’ of a hitherto unattributed fourteenth-century pulpitum screen. The stylistic context for the feature lies largely within the great architectural lodges of south-west England. There are strong grounds for suggesting that its designer was the innovative master, William Joy. If this attribution is correct, the commission is probably to be dated to the later 1320s, and no later than c 1330. The fact that the patrons for this prestigious work were the White Monks of Tintern serves only to underline its importance. From the surviving evidence, the construction of such an elaborate pulpitum within a British Cistercian context appears to have been an especially rare occurrence.