bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid Nanostructured Ni(OH)2/NiO for High-Capacity Lithium-Ion Battery Anodes
Authors: Ren Yang , Ko Jesse S. , Kasse Robert M. , Song Xuefeng , Toney Michael F. , Nelson Weker Johanna
Published: February 2020

A straightforward hydrothermal process followed by a controlled calcination technique is proposed for the synthesis of a Ni(OH)2 modified NiO nanohybrid structure. Conversion materials such as Li-ion battery anodes, NiO in this case, suffer from capacity fade and structural/morphological instability during lithiation and delithiation. The novelty of this work is in utilizing this hybrid configuration to increase the specific capacity and enable reversible electrochemistry. In the present work, we study the lithiation/delithiation process of NiO using a suite of spectroscopy and microscopy techniques from the atomic to electrode scale. We propose a mechanism for a reversible redox couple behavior of the NiO electrode by means of a hybrid Ni(OH)2/NiO structure. The ultimate objective of this work is to guide the development of anode with rationally designed heterogeneity to create high-capacity Li-ion batteries with excellent cycling and rate performance.
Integrated Intelligence of Fractional Neural Networks and Sequential Quadratic Programming for Bagley–Torvik Systems Arising in Fluid Mechanics
Authors: Raja Muhammad Asif Zahoor , Manzar Muhammad Anwaar , Shah Syed Muslim , Chen YangQuan
Published: February 2020

In this study, an efficient soft computing paradigm is presented for solving Bagley–Torvik systems of fractional order arising in fluid dynamic model for the motion of a rigid plate immersed in a Newtonian fluid using feed-forward fractional artificial neural networks (FrANNs) and sequential quadratic programming (SQP) algorithm. The strength of FrANNs has been utilized to construct an accurate modeling of the equation using approximation theory in mean square error sense. Training of weights of FrANNs is performed with SQP techniques. The designed scheme has been examined on different variants of the systems. The comparative studies of the proposed solutions with available exact as well as reference numerical results demonstrate the worth and effectiveness of the solver. The accuracy, consistency, and complexity are evaluated in depth through results of statistics.
Simultaneous Resonance and Anti-Resonance in Dynamical Systems Under Asynchronous Parametric Excitation
Authors: Karev Artem , Hagedorn Peter
Published: February 2020

Since the discovery of parametric anti-resonance, parametric excitation has also become more prominent for its stabilizing properties. While resonance and anti-resonance are mostly studied individually, there are systems where both effects appear simultaneously at each combination resonance frequency. With a steep transition between them and a high sensitivity of their relative positions, there is a need for a concurrent study of resonance and anti-resonance. The semi-analytical method of normal forms is used to derive approximate analytical expressions describing the magnitude of the stability impact as well as the precise locations of stabilized and destabilized areas. The results reveal that the separate appearance of resonance and anti-resonance is only a special case occurring for synchronous parametric excitation. In particular, in circulatory systems the simultaneous appearance is expected to be much more common.
Locomotion of a Compliant Mechanism With Nonholonomic Constraints
Authors: Fedonyuk Vitaliy , Tallapragada Phanindra
Published: February 2020

Compliant mechanisms have been studied extensively as an alternative to traditional rigid body design with advantages like part number reduction, compliance, and multistable configurations. Most of the past research on compliant mechanisms has been restricted to the case where they are subject to holonomic constraints. In this paper, we develop a model of a planar compliant mechanism with nonholonomic constraints as a mobile robot that can move on the ground. The only actuation that is assumed is a torque on the system. It is shown that the dynamics of this system is similar to that of a well-known nonholonomic system, called the Chaplygin sleigh, but with an added degree-of-freedom and an additional quartic potential. The interaction of compliance and the nonholonomic constraint lead to multiple stable limit cycle oscillations in a reduced velocity space that correspond to oscillations about different stable physical configurations. These limit cycle oscillations produce motion of the compliant mechanism in the plane with differing characteristics. The modeling framework in this paper can form the basis for the design of underacted mobile compliant nonholonomic robots or mobile robots that incorporate compliant mechanisms as mechanical switches.
Thermal Management of Li-Ion Batteries by Embedding Microgrooves Inside the Electrodes: A Thermal Lattice Boltzmann Method Study
Authors: Mohammadian Shahabeddin K. , Zhang Yuwen
Published: February 2020

One way to enhance the thermal performance of the Li-ion batteries is embedding microgrooves inside the porous electrodes and flowing the electrolyte through these microgrooves. Heat transfer from the battery can be enhanced by having both convection and conduction heat transfers inside the electrodes, instead of conduction heat transfer alone. A two-dimensional thermal lattice Boltzmann method (LBM) was employed to predict electrolyte flow, heat transfer, and internal heat generation inside the positive porous electrode. Size and number of the microgrooves and the electrolyte flow velocity inside them were investigated, and it was found that embedding microgrooves inside the porous electrode improved the thermal performance of the Li-ion battery by keeping the electrode in lower temperatures and improving its temperature uniformity. Furthermore, increasing the electrolyte flow velocity as well as increasing the number of microgrooves (in a constant ratio between the total size of the microgrooves to the size of the porous electrode) kept the porous electrode in lower temperatures and enhanced temperature uniformity.
Photovoltaic and charge trapping characteristics of multilayer silver embedded in molybdenum oxides as hole-selective layers for screen-printed monocrystalline silicon solar cell applications
Authors: Cheng Chin-Lung , Liu Chi-Chung , Shen Yu-Wang
Published: February 2020

Rear surface morphology and multilayer silver embedded in molybdenum oxides as hole-selective layers (HSLs) were proposed to enhance the photovoltaic characteristics of screen-printed monocrystalline silicon solar cells (SPMSCs). Moreover, the charge trapping characteristic of multilayer silver embedded in molybdenum oxides was presented. The results suggested an improvement in the conversion efficiency of more than 1.0% absolute from 17.7% to 18.7% for SPMSCs with a flat rear surface and three layers of Ag embedded in MoOx as HSLs were demonstrated. The mechanism was attributed to an increase in a negative fixed charge and high rear reflection.
Effect of Volume on Eccentric Overload–Induced Postactivation Potentiation of Jumps
Authors: de Keijzer Kevin L. , McErlain-Naylor Stuart A. , Dello Iacono Antonio , Beato Marco
Published: February 2020

Purpose: To investigate the postactivation potentiation (PAP) effects of different eccentric overload (EOL) exercise volumes on countermovement-jump (CMJ) and standing-long-jump (LJ) performance. Methods: In total, 13 male university soccer players participated in a crossover design study following a familiarization period. Control (no PAP) CMJ and LJ performances were recorded, and 3 experimental protocols were performed in a randomized order: 1, 2, or 3 sets of 6 repetitions of flywheel EOL half-squats (inertia = 0.029 kg·m2). Performance of CMJ and LJ was measured 3 and 6 minutes after all experimental conditions. The time course and magnitude of the PAP were compared between conditions. Results: Meaningful positive PAP effects were reported for CMJ after 2 (Bayes factor [BF10] = 3.15, moderate) and 3 (BF10 = 3.25, moderate) sets but not after 1 set (BF10 = 2.10, anecdotal). Meaningful positive PAP effects were reported for LJ after 2 (BF10 = 3.05, moderate) and 3 (BF10 = 3.44, moderate) sets but not after 1 set (BF10 = 0.53, anecdotal). The 2- and 3-set protocols resulted in meaningful positive PAP effects on both CMJ and LJ after 6 minutes but not after 3 minutes. Conclusion: This study reported beneficial effects of multiset EOL exercise over a single set. A minimum of 2 sets of flywheel EOL half-squats are required to induce PAP effects on CMJ and LJ performance of male university soccer players. Rest intervals of around 6 minutes (>3 min) are required to maximize the PAP effects via multiple sets of EOL exercise. However, further research is needed to clarify the optimal EOL protocol configurations for PAP response.
“Don’t Touch My Bag”: The Role of Superstition in Professional Male Boxing
Authors: Allen Georgia , Thornton Claire , Riby Holly
Published: February 2020

The superstitious actions athletes undertake before competition have been well documented, yet the role of such behaviors has received little qualitative attention. The aim of this study was to explore the role of superstitious routines in professional male boxing. A descriptive phenomenological approach was adopted, and individual semistructured interviews were conducted with 5 professional male athletes in the United Kingdom. Results show that superstition is regularly used by boxers in the lead-up to fights to aid mental preparation, fulfill a need for control, and improve the likelihood of success. Common themes emerged, such as the use of praying and engagement in acts thought to bring good luck and/or the avoidance of behaviors that might bring bad luck. Findings also indicate that despite a rational link, boxers use superstition as a coping mechanism (e.g., as a scapegoat/excuse for losing) and to gain a sense of control.
Robotic versus laparoscopic gastrectomy for gastric cancer: protocol for umbrella review of systematic reviews and meta-analyses
Authors: Marano Luigi , Fusario Daniele , Savelli Vinno , Verre Luigi , Neri Alessandro , Marrelli Daniele , Roviello Franco
Published: February 2020

Introduction

Laparoscopic surgery has been adopted in some parts of the world as an innovative approach to the resection of gastric cancers. However, in the modern era of surgical oncology, to overcome intrinsic limitations of the traditional laparoscopy, the robotic approach is advocated as able to facilitate the lymph node dissection and complex reconstruction after gastrectomy, to assure oncologic safety also in advanced gastric cancer patients. Previous meta-analyses highlighted a lower complication rate as well as bleeding in the robotic approach group when compared with the laparoscopic one. This potential benefit must be balanced against an increased time of intervention. The aim of this umbrella review is to provide a comprehensive overview of the literature for surgeons and policymakers in order to evaluate the potential benefits and harms of robotic gastrectomy (RG) compared with the laparoscopic approach for gastric cancer.

Methods and analysis

We will perform a comprehensive search of the PubMed, Cochrane and Embase databases for all articles published up to May 2019 and reference list of relevant publications for systematic review and meta-analyses comparing the outcomes of RG and laparoscopic gastrectomy in patients with gastric cancer. Studies will be selected by two independent reviewers based on prespecified eligibility criteria and the quality will be assessed according to AMSTAR (A MeaSurement Tool to Assess systematic Reviews) checklist. All information will be collected using piloted and standardised data-extraction forms in DistillerSR developed following the Joanna Briggs Institute’s recommended extraction items.

Ethics and dissemination

This umbrella review will inform clinical and policy decisions regarding the benefits and harms of RG for treating gastric cancer. The results will be disseminated through a peer-reviewed publication, conference presentations and the popular press. Formal ethical approval is not required as primary data will not be collected.

PROSPERO registration number

CRD42019139906.
Clinical teaching unit design: a realist systematic review protocol of evidence-based practices for clinical education and health service delivery
Authors: Tang Brandon , Sandarage Ryan , Dutkiewicz Katrina , Saad Stephan , Chai Jocelyn , Dawson Kristin , Kitchin Vanessa , McCormick Iain , Kassen Barry
Published: February 2020

Introduction

The clinical teaching unit (CTU) has emerged as a near-ubiquitous model of clinical education across Canadian and international medical schools since it was first proposed over 50 years ago. However, while healthcare has changed dramatically over this period, the CTU model has remained largely unchanged. We thus aimed to systematically review principles of CTU design that contribute to improved outcomes in clinical education and health service delivery.

Methods and analysis

We will perform a realist systematic review in accordance with the Realist And Meta-narrative Evidence Syntheses: Evolving Standards (RAMESES) II protocol for realist reviews. Databases, including MEDLINE, Embase, Cochrane Database of Systematic Reviews and Cumulative Index of Nursing and Allied Health Literature (CINAHL), were searched to find primary research articles published from 1993 to 2019 involving CTUs or other teaching wards, and outcomes related to either trainee education or health service delivery. Two reviewers will independently screen studies in a two-stage process. Retrieved titles and/or abstracts of studies will be screened in the first stage, with full texts reviewed in the second stage. Selected articles meeting inclusion criteria will undergo data abstraction using a standardised, pre-piloted form for assessment of study quality and knowledge synthesis.

Ethics and dissemination

This review will generate higher quality evidence on the design of CTUs as a model for both clinical education and health service delivery. In addition, further knowledge translation efforts may be necessary to ensure that known best practices in CTU design become common practice.
Developing an Australian multi-module clinical quality registry for gynaecological cancers: a protocol paper
Authors: Heriot Natalie , Brand Alison , Cohen Paul , Hegarty Sue , Hyde Simon , Leung Yee , Zalcberg John R , Rome Robert
Published: February 2020

Introduction

Gynaecological cancers collectively account for almost 10% of cancer diagnoses made in Australian women. The extent of variation in gynaecological cancer survival rates and treatment outcomes across Australia is not well documented. The purpose of the clinical quality registry described in this paper is to systematically monitor and improve quality of care provided to these women, and facilitate clinical process improvements to ensure better patient outcomes and greater adherence to best practice care. The registry infrastructure has been developed in conjunction alongside the inaugural ovarian, tubal and peritoneal (OTP) module, allowing for concurrent piloting of the methodology and one module. Additional tumour modules will be developed in time to cover the other gynaecological tumour types.

Method and analysis

The National Gynae-Oncology Registry (NGOR) aims to capture clinical data on all newly diagnosed cancers of the uterus, ovary, fallopian tubes, peritoneum, cervix, vulva and vagina in Australia with a view to using these data to support improved clinical care and increased adherence to ‘best practice’. Data are sourced from existing clinical databases maintained by clinicians and/or hospital gynaecological cancer units. A pilot phase incorporating only OTP cancers has recently been conducted to assess the feasibility of the registry methodology and assess the support of a quality initiative of this nature among clinicians and other key stakeholders.

Ethics and dissemination

The NGOR has received National Mutual Acceptance (NMA) ethics approval from Monash Health Human Research Ethics Committee (HREC), NMA HREC Reference Number: HREC/17/MonH/198. We also have approval from Mercy Health HREC and University of Tasmania HREC. Data will be routinely reported back to participating sites illustrating their performance against measures of agreed best practice. It is through this feedback system that the registry will support changes to quality of care and improved patient outcomes.
Incidence, risk factors and outcome of young patients with myocardial infarction
Authors: Jortveit Jarle , Pripp Are Hugo , Langørgen Jørund , Halvorsen Sigrun
Published: February 2020

Objective

The decline in the incidence and mortality of acute myocardial infarction (AMI) has been less among younger compared with older individuals. The aim of this nationwide study was to assess the current incidence, risk factors and outcome of AMI in patients <45 years of age.

Methods

All patients ≤80 years of age registered in the Norwegian Myocardial Infarction Register in 2013–2016 were included in this observational, nationwide cohort study. Follow-up was conducted through linkage with the Norwegian Patient Registry through 2017.

Results

Among a total of 33 439 patients ≤80 years with AMI, 1468 (4.4%) were <45 years old. The incidence of AMI was 2.1 per 100 000 person-years in people aged 20–29 years, 16.9 in people aged 30–39 years and 97.6 in people aged 40–49 years. Compared with older patients, patients <45 years were more likely to be male (81%), current smokers (56%), obese (30%) and have a family history of premature AMI (44%), and their low-density lipoprotein-cholesterol levels were higher. Patients <45 years were more likely to have non-obstructive coronary artery disease (14% vs 10%, p<0.001) compared with older patients. During a median follow-up time of 2.4 years, 135 (9%) patients <45 years experienced a new AMI, stroke or death, and 58 (4%) patients died.

Conclusions

The rate of AMI was low in people <45 years old in Norway, but almost one in ten patients with AMI <45 years old died or experienced a new cardiovascular event during follow-up. Increased efforts to improve risk factor control in these patients are warranted.
ARID1Aalterations function as a biomarker for longer progression-free survival after anti-PD-1/PD-L1 immunotherapy
Authors: Okamura Ryosuke , Kato Shumei , Lee Suzanna , Jimenez Rebecca E , Sicklick Jason K , Kurzrock Razelle
Published: February 2020

Background

Several cancer types harbor alterations in the gene encoding AT-Rich Interactive Domain-containing protein 1A (ARID1A), but there are no approved therapies to address these alterations. Recent studies have shown thatARID1Adeficiency compromises mismatch repair proteins. Herein, we analyzed 3403 patients who had tumor tissue next-generation sequencing.

Findings

Among nine cancer subtypes with >5% prevalence ofARID1Aalterations, microsatellite instability-high as well as high tumor mutational burden was significantly more frequent inARID1A-altered versusARID1Awild-type tumors (20% vs 0.9%, p<0.001; and 26% vs 8.4%, p<0.001, respectively). Median progression-free survival (PFS) after checkpoint blockade immunotherapy was significantly longer in the patients withARID1A-altered tumors (n=46) than in those withARID1Awild-type tumors (n=329) (11 months vs 4 months, p=0.006). Also, multivariate analysis showed thatARID1Aalterations predicted longer PFS after checkpoint blockade (HR (95% CI), 0.61 (0.39 to 0.94), p=0.02) and this result was independent of microsatellite instability or mutational burden; median overall survival time was also longer inARID1A-altered versus wild-type tumors (31 months vs 20 months), but did not reach statistical significance (p=0.13).

Conclusions

Our findings suggest thatARID1Aalterations merit further exploration as a novel biomarker correlating with better outcomes after checkpoint blockade immunotherapy.
Syrian Civil War: a systematic review of trauma casualty epidemiology
Authors: McIntyre Joshua
Published: February 2020

Background

The Syrian Civil War has caused over 400 000 traumatic deaths. Understanding the nature of war casualties is crucial to deliver healthcare improvement. Historic regional conflicts and Syrian mortality data have been characterised by blast injuries. The aim of this novel review is to assess the trauma epidemiology of Syrian Civil War casualties from the perspective of healthcare facilities.

Methods

This review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses method. Studies addressing Syria, trauma and war were investigated. Eligibility criteria included being conducted from a healthcare facility, published in English and peer reviewed. The outcomes were demography, mechanism of injury and anatomical injury site.

Results

38 papers satisfied the eligibility criteria. 13 842 casualties were reported across the entire data set. Casualties were 88.8% male (n=4035 of 4544). Children contributed to 16.1% of cases (n=398 of 2469). Mortality rate was 8.6% (n=412 of 4774). Gunshot wound was the most common mechanism of injury representing 66.3% (n=7825 of 11799). Head injury was the most common injured site at 26.6% (n=719 of 2701).

Conclusions

This conflict has a distinct trauma profile compared with regional modern wars. The prevalence of gunshot wounds represents a marked change in mechanism of injury. This may be related to higher mortality rate and proportion of head injuries identified. This review cannot correlate mechanism of injury, demographics or injuries sustained to outcomes. The quality of data from the included studies lacked standardisation; future research and consistent reporting tools are required to enable further analysis.
Analysis of cases managed by dermatological service in the Chinese peacekeeping level 1+ medical treatment facility in Lebanon, 2018–2019
Authors: Wang Xingwang , Yang H , Wang Yuqing , Yuan Jin , Yu Qinghua
Published: February 2020

Introduction

To accomplish the peacekeeping mission in Lebanon, China has deployed a level 1+ (CHN L1+) medical treatment facility (MTF) as per the new memorandum. The aim of this study was to review and analyse the skin diseases managed by Chinese dermatological service so as to gain the latest prevalence of different types of skin diseases in this mission area.

Methods

All patients assessed and treated by the dermatological service of CHN L1+ MTF from January 2018 to May 2019 were included. A comparative analysis was made between this study and data published by other peacekeeping medical facilities.

Results

A total of 549 patients were included (87.4% men, with an average age of 35 years old), consisting of 399 military personnel and 150 civilians. Dermatitis and eczema (27.1%) were the most common category of skin diseases, followed by cutaneous mycoses (13.3%) and disorders of skin appendages (10.6%). Among these categories, unspecified dermatitis (9.3%), acne vulgaris (6.6%), tinea corporis (5.3%), folliculitis (5.1%) and tinea pedis (4.7%) were the top five most common reasons for dermatological consultation.

Conclusions

To get a clearer understanding of the disease-type profile in this mission area was beneficial for peacekeeping doctors to make more accurate diagnosis, as well as to prepare more comprehensive medicines during the predeployment period. As dermatological service was lacking in basic medical troops, we would recommend the use of telemedicine to promote dermatological consultations when a specialist was not deployed.
Extending the record of the Lomagundi–Jatuli carbon isotope excursion in the Labrador Trough, Canada
Authors: Hodgskiss Malcolm S.W. , Lamothe Kelsey G. , Halverson Galen P. , Sperling Erik A.
Published: February 2020

The Labrador Trough in northern Québec and Labrador is a 900 km long Rhyacian–Orosirian orogenic belt containing mixed sedimentary–volcanic successions. Despite having been studied intensively since the 1940s, relatively few chemostratigraphic studies have been conducted. To improve our understanding of the Labrador Trough in the context of Earth history, and better constrain the local record of the Lomagundi–Jatuli carbon isotope excursion, high-resolution sampling and carbon isotope analyses of the Le Fer and Denault formations were conducted. Carbonate carbon isotopes (δ13C) in the Le Fer Formation record a large range in values from −4.4‰ to +6.9‰. This large range is likely attributable to a combination of post-depositional alteration and variable abundance of authigenic carbonate minerals; elemental ratios suggest that the most 13C-enriched samples reflect the composition of the water column at the time of deposition. Cumulatively, these data suggest that the Lomagundi–Jatuli Excursion was ongoing during deposition of the Le Fer Formation, approximately 2 km higher in the stratigraphy than previously recognised. However, the possibility of a post-Lomagundi–Jatuli Excursion carbon isotope event cannot conclusively be ruled out. The directly overlying Denault Formation records a range in δ13C values, from −0.5‰ to +4.3‰, suggesting that it was deposited after the conclusion of the Lomagundi–Jatuli Excursion and that the contact between the Le Fer and Denault formations occurred sometime during the transition out of the Lomagundi–Jatuli Excursion, ca. 2106 to 2057 Ma.
Fibration and classification of smooth projective toric varieties of low Picard number
Authors: Rossi Michele , Terracini Lea
Published: February 2020

In this paper, we show that a smooth toric variety [Formula: see text] of Picard number [Formula: see text] always admits a nef primitive collection supported on a hyperplane admitting non-trivial intersection with the cone [Formula: see text] of numerically effective divisors and cutting a facet of the pseudo-effective cone [Formula: see text], that is [Formula: see text]. In particular, this means that [Formula: see text] admits non-trivial and non-big numerically effective divisors. Geometrically, this guarantees the existence of a fiber type contraction morphism over a smooth toric variety of dimension and Picard number lower than those of [Formula: see text], so giving rise to a classification of smooth and complete toric varieties with [Formula: see text]. Moreover, we revise and improve results of Oda–Miyake by exhibiting an extension of the above result to projective, toric, varieties of dimension [Formula: see text] and Picard number [Formula: see text], allowing us to classifying all these threefolds. We then improve results of Fujino–Sato, by presenting sharp (counter)examples of smooth, projective, toric varieties of any dimension [Formula: see text] and Picard number [Formula: see text] whose non-trivial nef divisors are big, that is [Formula: see text]. Producing those examples represents an important goal of computational techniques in definitely setting an open geometric problem. In particular, for [Formula: see text], the given example turns out to be a weak Fano toric fourfold of Picard number 4.
Controllable optical steady-state behavior at multi-frequency channels
Authors: Duan Bao-Rui , Yan Xiang-An , Ren Bo-Quan , Gao Huan-Qin , Han Yu-Jing , Xu Wan-Ting , Wu Jun-Fang
Published: February 2020

We identify a scheme in which we can control the behavior of an atomic medium to switch between optical bistability (OB) and optical multistability (OM) at multiple frequencies. The scheme relies on the absorption and dispersion characteristics of the optical medium at different frequencies, which can be modulated significantly by changing the magnetic field [Formula: see text] for tuning the energy difference between Zeeman sublevels. The result shows that the transition from OB to OM or vice versa can be easily realized not only at single frequency channel but also between multiple frequency channels. Furthermore, the optical steady-state behavior also varies with the ratio of the applied two coupling fields at any frequency channel. Such controllable switching between multiple frequency channels could also be used as some applications in all-optical switching and quantum information processing.
Effects of inhomogeneous laser field in time and space on the generation of broad spectral continuum and ultrashort attosecond pulse
Authors: Liu H. , Feng L. Q. , Sani R. M.
Published: February 2020

The inhomogeneous effects of laser field in time and space on the generations of high-order harmonic spectra and attosecond pulses from He atom have been investigated with the assistance of the frequency-chirping technique and the metallic nanostructure. We find that in different combinations of chirps and spatial inhomogeneous effects, not only can the harmonic cutoff be extended, but the single harmonic emission peak (HEP) can also be selected to contribute to the spectral continuum. In detail, with the combinations of (i) symmetric chirp in frequency and positive inhomogeneous effect in space or (ii) asymmetric down chirp in frequency and negative inhomogeneous effect in space, two broad spectral continua with bandwidths of 496 eV and 480 eV can be obtained. Further, by properly adding IR or UV controlling pulse, the harmonic emission efficiency can be enhanced by several orders of magnitude. The enhancement of harmonic yield from adding UV pulse is higher than that from adding IR pulse. Moreover, the difference of harmonic enhancement between UV combined field and IR combined field is much more obvious at lower controlling laser intensity. Through analyzing the ionization probability, we find that the higher enhancement of harmonic yield from UV combined field is because of UV-resonance-enhancement-ionization between the ground state and the excited state of He atom. Finally, by properly superposing some harmonics, a number of attosecond pulses with pulse durations of 45 as can be obtained.
The local extinction and the nonlinear behaviors of a premixed methane/air flame under low-frequency acoustic excitation
Authors: Sun Yongchao , Sun Mingbo , Zhu Jiajian , Xie Yang , Wang Hongbo , Wan Minggang , Chen Yong
Published: February 2020

The local extinction and the nonlinear behavior of a premixed methane/air flame under acoustic excitation are investigated experimentally. High-speed photography and high-speed schlieren imaging are used to investigate the oscillation characteristics of the premixed methane/air flame. The flame structure shows a periodic fluctuation when the acoustic excitation is performed to the flame. The local flame extinction can be observed during the flame evolution process. During the local flame extinction process, the flame is found to be cut into two components, then the downstream one extinguishes shortly. The Particle Image Velocimetry (PIV) results suggest that the lower velocity at the separation point is one of the reasons for the flame local extinction. The flame without the acoustic excitation oscillates with a dominant frequency of 18 Hz, which is shown by the schlieren images to be related to the evolution of the hot gas around the flame driven by the buoyant force. When the acoustic excitation frequency is 100 Hz, the structure of the hot gas is destroyed, meanwhile the amplitude of the nature frequency decreases significantly. The hot gas structure appears regularly with the increasing excitation frequency. As a result, the amplitude of the nature frequency also increases gradually. Proper Orthogonal Decomposition (POD) analysis shows that the dominant frequency of the flame without the acoustic excitation is mainly caused by the evolution of the production zone of the flame and the fluctuation of the flame tip. The evolution of the production zone is driven by the buoyant force, which indicates that the result from POD method is consistent with the conclusion obtained from the high-speed schlieren images. Two dominant modes are obtained when the excitation frequencies are 100 and 200 Hz. The two modes are mainly caused by the process of the local flame extinction and the increasing flame length.
Community detection based on gravitational coefficient in collaboration network
Authors: Zhou Wen , Zhao Shuaiqin
Published: February 2020

One important characteristic of complex networks is community structure. How to effectively divide the potential community structure of complex networks has been the focus of scholars because communities may have very different properties than the network. A community is usually defined as a collection of nodes with similar attributes. Generally, nodes in the same community are relatively densely connected to each other, compared with nodes from different communities. From the perspective of clustering, nodes in the same community can be considered as having higher similarities. Therefore, using graph clustering algorithms for community detection is theoretically feasible. Collaborative networks are special complex networks. A collaborative relationship tends to connect to multiple collaborators, which makes it hard to build collaborative networks by abstracting the collaboration into edges. Based on characteristics of the collaborative network, we expand the cluster similarity index and propose a gravitational coefficient index to measure the similarity of nodes and subsequently design community detection algorithms. Experiments using real datasets show that the proposed algorithm can obtain higher quality community partitioning results and avoid falling into local optimal solutions to obtain larger-scale communities than classical community detection algorithms.
Field experiment and analysis for free-space laser transmission characteristic in turbulent path based on MWIR and NIR
Authors: Wang Wei , Bai Zhaofeng , Xie Xiaoping , Mei Haiping , Zhao Wei
Published: February 2020

It is hard to achieve low bit error rate (BER) and high-quality signals in free-space optical (FSO) communication systems due to atmospheric link interference. For the sake of seeking solutions, we proposed an experimental scheme of free-space laser communication based on middle-wave infrared (MWIR) and near infrared (NIR) for obtaining atmospheric transmission characteristic in 1 km turbulence path. Compared with NIR waveband, MWIR-based scheme is more suitable for atmospheric FSO communication since it owns higher anti-interference ability for atmospheric attenuation, turbulence and skylight background noise. The experimental results may offer a significant reference for FSO communication in atmosphere link.
Fish Sound Characterization Using Multifractal Detrended Fluctuation Analysis
Authors: Chanda Kranthikumar , Shet Shubham , Chakraborty Bishwajit , Saran Arvind K. , Fernandes William , Latha G.
Published: February 2020

This work involves the application of a non-linear method, multifractal detrended fluctuation analysis (MFDFA), to describe fish sound data recorded from the open waters of two major estuarine systems. Applying MFDFA, the second-order Hurst exponent [Formula: see text] values are found to be [Formula: see text] and [Formula: see text] for the fish families Batrachoididae (common name: Toadfish) and Sciaenidae (common name: Croakers, drums), respectively. The generalized Hurst exponent [Formula: see text]-related width parameters [Formula: see text] are found to be [Formula: see text] and [Formula: see text], respectively, for toadfish and Sciaenidae vocalizations, implying greater heterogeneity and multifractal characteristics. The results suggest that the Sciaenidae fish calls are smoother in comparison with Batrachoididae. Clustering of multifractal spectrum-related parameters with respect to toadfish and Sciaenidae vocalization characteristics is observed in this analyses.
A mathematical model of cholera in a periodic environment with control actions
Authors: Kolaye G. , Damakoa I. , Bowong S. , Houe R. , Békollè D.
Published: February 2020

In this paper, we studied the impact of sensitization and sanitation as possible control actions to curtail the spread of cholera epidemic within a human community. Firstly, we combined a model of Vibrio Cholerae with a generic SIRS cholera model. Classical control strategies in terms of the sensitization of population and sanitation are integrated through the impulsive differential equations. Then we presented the theoretical analysis of the model. More precisely, we computed the disease free equilibrium. We derive the basic reproduction number [Formula: see text] which determines the extinction and the persistence of the infection. We show that the trivial disease-free equilibrium is globally asymptotically stable whenever [Formula: see text], while when [Formula: see text], the trivial disease-free equilibrium is unstable and there exists a unique endemic equilibrium point which is globally asymptotically stable. Theoretical results are supported by numerical simulations, which further suggest that the control of cholera should consider both sensitization and sanitation, with a strong focus on the latter.
Analysis of heat transfer processes for sapphire growth by horizontal directed crystallization method
Authors: Klunnikova Yu. V. , Malyukov S. P. , Filimonov A. V. , Zhang N.
Published: February 2020

This research summarizes the analytical and experimental results of heat-transfer processes influence on defects formation during sapphire crystal growth by horizontal directed crystallization method (HDC). The shape of solid-melt interface significantly influences the process of sapphire crystals growth by this method. We receive the Stefan problem solution for sapphire crystals growth. It allows investigating the crystal growth process and the related factors (thermal stresses on different stages of growth process), their influence on defects formation. We investigate the main reasons for the formation of defective structures of the solid phase of sapphire crystals and the influence of thermal unit construction, the crystal geometry on the quality of the resulting sapphire crystal. We study the structure formation process, impurity distribution, and the nature of the defects in the crystal during it growth.
Sandstone intrusions along different types of faults and their effect on fluid flow in siliciclastic reservoirs
Authors: Palladino G. , Alsop G. Ian , Grippa A. , Seers T. , Hurst A.
Published: February 2020

The principle aim of this paper is to document well-preserved field examples of sandstone-filled faults in order to raise awareness of these poorly understood structures, and discuss their potential as fault seals within injection-prone, multilayered siliciclastic reservoirs. To achieve this goal, we have undertaken a detailed field survey in the Panoche and Tumey hills in Central California, which allowed us to recognize numerous faults filled with injected sand. In particular, sandstone-filled extensional, contractional and strike-slip faults are observed cutting the sandstone/mudstone successions. Sandstone-filled faults commonly display small offsets and apertures ranging from a few centimetres to some decimetres. Evidence of tectonic deformation is usually lacking, meaning that sand injection supported by overpressured fluids propped open the fault walls. In this paper we also describe the main mechanism leading to the emplacement of sand along a fault plane, and propose a predictive model of sandstone-filled fault distributions in different structural environments. Finally, we discuss the role of sandstone-filled faults, that although relatively small and not adding significant volume to the reservoirs, can markedly increase fluid transmissibility and thereby promote better reservoir connectivity.
Morphological, mineral and geochemical characterization of soil profiles in Meïganga as tools for rock weathering intensity and trend evaluation and residual ore deposit prospection in the mineralized domain of central Cameroon
Authors: Tchaptchet T. W. , Tematio P. , Guimapi T. N. , Happi E. , Tiomo I. , Momo N. M.
Published: February 2020

This paper focuses on the use of morphological, mineral and geochemical characterization of soil profiles to assess rocks weathering trends and intensity as tools for mineral prospection in Meïganga. To that effect, seven soil profiles developed on micaschist, orthogneiss, granite and quartzite vein were analysed. Macroscopic description of these soil profiles exhibited shallow weathered soils with thickness not exceeding 4 m. Minerals recorded in their weathering products were: quartz, 60.3–93.9%; kaolinite, 0.8–22.3%; phlogopite, 0.2–15.3%; goethite, 1.9–13.0%; hematite, 0.5–8.5%; halloysite, 0.2–4.6%; and smectite, 0.5–4.3%. Geochemically, SiO
2
contents globally decreased upward, while Al
2
O
3
, Fe
2
O
3
and TiO
2
contents increased. Alkaline and alkaline earths contents were almost completely leached. The total reserve in bases and Parker's weathering index (TRB, 416–11 mg kg
−1
; WIP, 56–4%) decreased upward, except in the soil profile associated with the quartzite veins (TRB, 2–100 mg kg
−1
; WIP, 0–29%). The chemical index of alterations were 5–92% with the index of lateritization 8–39% and the silica exportation ratio was greatly above 1 (
K
i
2–9). Trace elements in soil profiles were, in order of decreasing contents, S, Ba, Sr, Zr, Cr, V, Zn, Rb, Ni, Y, Sb, Cu, Pb, Li, Co, Ga, Nb, Th, Sc, Cs, Hf, Sn, U, Mo and W. Scandium, V, Cr, Sb, Cs and Pb were enriched, while S, Rb and Sr were depleted, and Ba, Zr, Zn, Ni, Y, Cu, Li, Co, Ga, Nb, Th, Hf, Sn, U, Mo and W showed complex behaviour. The most abundant rare earth elements (REEs) were, in order of decreasing contents, Ce (29–273 ppm), La (26–91 ppm), Nd (14–83 ppm) and Pr (4–22 ppm). Almost all the REEs were enriched in soil profiles with respect to parent material, and strongly fractionated, with fractionation intensity increasing from light to heavy REEs. The most significant useful elements identified were: refractory metals (Zr, Cr, V, Nb, Hf, Mo and W), semi-precious metal (Cu), non-precious unreactive metal (Sb) and actinide group element (U). Statistical analysis indicated that, in soil profiles, Nb, Mo, U, W and Hf had strong affinity with Al
2
O
3
; Mo, Cr, V, Zr, Hf and Sb had strong affinity with with Fe
2
O
3
; U, Hf and Sb had strong affinity with with P
2
O
3
; and Nb, Zr, V and Cr had strong affinity with with TiO
2
. Fe
2
O
3
, Al
2
O
3
and TiO
2
are respectively the greatest markers for Mo; Nb, Mo, W, Nb and U; and Nb, V and Cr prospection in soil profiles. The Clarke of concentrations of useful elements were: Sb, 60.00; Mo, 0.83–4.17; W, 1.60; Cr, 0.08–1.56; Nb, 0.60–1.55; U, 1.11–1.48; Hf, 1.33; V, 0.36–1.27; and Zr, 0.96. Exploitability concentrations for Cr and U in soil profiles varied respectively from 1.20 to 23.85% and from 0.15 to 0.20%.
The refinement of flipped teaching implementation to include retrieval practice
Authors: Gopalan Chaya , Fentem Andrea , Rever Anna L.
Published: February 2020

There has been growing evidence that flipped teaching (FT) can increase student engagement. Traditional lecture-based teaching (TT) method was compared with FT and FT combined with retrieval practice (FTR) in a 400-level Exercise Physiology course over eight semesters. In the FT format, lecture content was assigned for students to prepare before class along with an online quiz. During class, the assigned content and quiz questions were reviewed, and a team-based learning (TBL) activity was conducted. Students found FT implementation three times a week (FT3) to be overwhelming, which led to reconfiguration of the FT design to minimize the quiz and TBL sessions to one per week. Subsequently, FT was combined with retrieval exercises (FTR), which involved recalling information, thus promoting retention. The students in the FTR format were given weekly quizzes in class, where no notes were allowed, which affected their quiz grade negatively compared with FT ( P < 0.0001). Again, no resources were permitted during FTR’s TBL sessions. When exam scores were compared with TT, student performance was significantly greater ( P < 0.001) with the FT and FTR methods, suggesting these methods are superior to TT. While both male and female students benefited from FT and FTR methods compared with TT ( P = 0.0008), male students benefited the most (( P = 0.0001). Similarly, when the exam scores were organized into upper and lower halves, both groups benefited from FT and FTR ( P < 0.0001) approaches. In conclusion, both FT and FTR methods benefit students more compared with TT, and male students are impacted the most.
Quantitative Analysis of Surface Contouring with Pulsed Bipolar Radiofrequency on Thin Chondromalacic Cartilage
Authors: Huber Michaela , Schlosser Daniela , Stenzel Susanne , Maier Johannes , Pattappa Girish , Kujat Richard , Striegl Birgit , Docheva Denitsa
Published: February 2020

The purpose of this study was to evaluate the quality of surface contouring of chondromalacic cartilage by bipolar radio frequency energy using different treatment patterns in an animal model, as well as examining the impact of the treatment onto chondrocyte viability by two different methods. Our experiments were conducted on 36 fresh osteochondral sections from the tibia plateau of slaughtered 6‐month‐old pigs, where the thickness of the cartilage is similar to that of human wrist cartilage. An area of 1 cm2 was first treated with emery paper to simulate the chondromalacic cartilage. Then, the treatment with RFE followed in 6 different patterns. The osteochondral sections were assessed for cellular viability (live/dead assay, caspase (cell apoptosis marker) staining, and quantitative analysed images obtained by fluorescent microscopy). For a quantitative characterization of none or treated cartilage surfaces, various roughness parameters were measured using confocal laser scanning microscopy (Olympus LEXT OLS 4000 3D). To describe the roughness, the Root‐Mean‐Square parameter (Sq) was calculated. A smoothing effect of the cartilage surface was detectable upon each pattern of RFE treatment. The Sq for native cartilage was Sq = 3.8 ± 1.1 μm. The best smoothing pattern was seen for two RFE passes and a 2‐second pulsed mode (B2p2) with an Sq = 27.3 ± 4.9 μm. However, with increased smoothing, an augmentation in chondrocyte death up to 95% was detected. Using bipolar RFE treatment in arthroscopy for small joints like the wrist or MCP joints should be used with caution. In the case of chondroplasty, there is a high chance to destroy the joint cartilage.
Real‐Time Detection of Hemothorax and Monitoring its Progression in a Piglet Model by Electrical Impedance Tomography: A Feasibility Study
Authors: Yang Lin , Zhang Chao , Liu Wenbo , Wang Hang , Xia Junying , Liu Benyuan , Shi Xuetao , Dong Xiuzhen , Fu Feng , Dai Meng
Published: February 2020

Hemothorax is a serious medical condition that can be life‐threatening if left untreated. Early diagnosis and timely treatment are of great importance to produce favorable outcome. Although currently available diagnostic techniques, e.g., chest radiography, ultrasonography, and CT, can accurately detect hemothorax, delayed hemothorax cannot be identified early because these examinations are often performed on patients until noticeable symptoms manifest. Therefore, for early detection of delayed hemothorax, real‐time monitoring by means of a portable and noninvasive imaging technique is needed. In this study, we employed electrical impedance tomography (EIT) to detect the onset of hemothorax in real time on eight piglet hemothorax models. The models were established by injection of 60 ml fresh autologous blood into the pleural cavity, and the subsequent development of hemothorax was monitored continuously. The results showed that EIT was able to sensitively detect hemothorax as small as 10 ml in volume, as well as its location. Also, the development of hemothorax over a range of 10 ml up to 60 ml was well monitored in real time, with a favorable linear relationship between the impedance change in EIT images and the volume of blood injected. These findings demonstrated that EIT has a unique potential for early diagnosis and continuous monitoring of hemothorax in clinical practice, providing medical staff valuable information for prompt identification and treatment of delayed hemothorax.