bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Discrete Random Walk Stochastic Model for Simulating Particle Dispersion and Deposition in Inhomogeneous Turbulent Flows
Authors: Mofakham Amir A. , Ahmadi Goodarz
Published: June 2020

The performance of different versions of the discrete random walk models in turbulent flows with nonuniform normal root-mean-square (RMS) velocity fluctuations and turbulence time scales were carefully investigated. The OpenFOAM v2−f low Reynolds number turbulence model was used for evaluating the fully developed streamwise velocity and the wall-normal RMS velocity fluctuations profiles in a turbulent channel flow. The results were then used in an in-house matlab particle tracking code, including the drag and Brownian forces, and the trajectories of randomly injected point-particles with diameters ranging from 10 nm to 30 μm were evaluated under the one-way coupling assumption. The distributions and deposition velocities of fluid-tracer and finite-size particles were evaluated using the conventional-discrete random walk (DRW) model, the modified-DRW model including the velocity gradient drift correction, and the new improved-DRW model including the velocity and time gradient drift terms. It was shown that the conventional-DRW model leads to superfluous migration of fluid-point particles toward the wall and erroneous particle deposition rate. The concentration profiles of tracer particles obtained by using the modified-DRW model still are not uniform. However, it was shown that the new improved-DRW model with the velocity and time scale drift corrections leads to uniform distributions for fluid-point particles and reasonable concentration profiles for finite-size heavy particles. In addition, good agreement was found between the estimated deposition velocities of different size particles by the new improved-DRW model with the available data.
Design Optimization of the Impeller and Volute of a Centrifugal Pump to Improve the Hydraulic Performance and Flow Stability
Authors: Shim Hyeon-Seok , Kim Kwang-Yong
Published: June 2020

Multi-objective design optimization was applied to the impeller and volute of a centrifugal pump using surrogate-based optimization techniques and three-dimensional Reynolds-averaged Navier–Stokes (RANS) analysis. The objective functions used to improve the hydraulic performance and operating stability of the pump were the hydraulic efficiency at the design condition and the flow rate at which the maximum volute pressure recovery coefficient occurs. Three design variables were selected based on the results of a sensitivity analysis: the blade outlet angle, the constants in determining the impeller outlet width, and the cross-sectional area of the volute. Using response surface approximation (RSA), surrogate models were constructed for the objective functions based on numerical results at experimental points obtained by Latin hypercube sampling (LHS). The representative Pareto-optimal solutions obtained by the multi-objective genetic algorithm (MOGA) show enhanced objective function values compared to the baseline design. The results of unsteady calculation show that the flow instability of the centrifugal pump was successfully suppressed by the optimization.
Interspecies Differences in Tenofovir Alafenamide Fumarate Stability in Plasma
Authors: Parsons Teresa L. , Gwenden Kevin N. , Marzinke Mark A.
Published: June 2020

Tenofovir (TFV) alafenamide fumarate (TAF) is an antiretroviral that has been evaluated in alternative drug delivery systems in several species. The
ex vivo
stability of TAF was evaluated, and TAF was stable in dog-, sheep-, and macaque-spiked plasma. A negative bias was observed in TAF recovery in rabbit-spiked plasma; there was complete loss of TAF and corresponding overestimation of TFV in rodent-spiked plasma. These data highlight considerations when evaluating TAF and TFV concentrations in preclinical studies.
Division without Binary Fission: Cell Division in the FtsZ-Less
Chlamydia
Authors: Ouellette Scot P. , Lee Junghoon , Cox John V.
Published: June 2020

Chlamydia
is an obligate intracellular bacterial pathogen that has significantly reduced its genome size in adapting to its intracellular niche. Among the genes that
Chlamydia
has eliminated is
ftsZ
, encoding the central organizer of cell division that directs cell wall synthesis in the division septum. These Gram-negative pathogens have cell envelopes that lack peptidoglycan (PG), yet they use PG for cell division purposes. Recent research into chlamydial PG synthesis, components of the chlamydial divisome, and the mechanism of chlamydial division have significantly advanced our understanding of these processes in a unique and important pathogen.
Lipidomic and Ultrastructural Characterization of the Cell Envelope of Staphylococcus aureus Grown in the Presence of Human Serum
Authors: Hines Kelly M. , Alvarado Gloria , Chen Xi , Gatto Craig , Pokorny Antje , Alonzo Francis , Wilkinson Brian J. , Xu Libin
Published: June 2020

Comprehensive lipidomics of
S. aureus
grown in the presence of human serum suggests that human serum lipids can associate with the cell envelope without being truly integrated into the lipid membrane. However, fatty acids derived from human serum lipids, including unsaturated fatty acids, can be incorporated into lipid classes that can be biosynthesized by
S. aureus
itself. Cholesteryl esters and triglycerides are found to be the major source of incorporated fatty acids upon hydrolysis by lipases. These findings have significant implications for the nature of the
S. aureus
cell surface when grown
in vivo
. Changes in phospholipid and glycolipid abundances and fatty acid composition could affect membrane biophysics and function and the activity of membrane-targeting antimicrobials. Finally, the association of serum lipids with the cell envelope has implications for the physicochemical nature of the cell surface and its interaction with host defense systems.
An analysis of International Health Regulations Emergency Committees and Public Health Emergency of International Concern Designations
Authors: Mullen Lucia , Potter Christina , Gostin Lawrence O , Cicero Anita , Nuzzo Jennifer B
Published: June 2020

Introduction

Nine events have been assessed for potential declaration of a Public Health Emergency of International Concern (PHEIC). A PHEIC is defined as an extraordinary event that constitutes a public health risk to other states through international spread and requires a coordinated international response. The WHO Director-General convenes Emergency Committees (ECs) to provide their advice on whether an event constitutes a PHEIC. The EC rationales have been criticised for being non-transparent and contradictory to the International Health Regulations (IHR). This first comprehensive analysis of EC rationale provides recommendations to increase clarity of EC decisions which will strengthen the IHR and WHO’s legitimacy in future outbreaks.

Methods

66 EC statements were reviewed from nine public health outbreaks of influenza A, Middle East respiratory syndrome coronavirus, polio, Ebola virus disease, Zika, yellow fever and coronavirus disease-2019. Statements were analysed to determine which of the three IHR criteria were noted as contributing towards the EC’s justification on whether to declare a PHEIC and what language was used to explain the decision.

Results

Interpretation of the criteria were often vague and applied inconsistently. ECs often failed to describe and justify which criteria had been satisfied.

Discussion

Guidelines must be developed for the standardised interpretation of IHR core criteria. The ECs must clearly identify and justify which criteria have contributed to their rationale for or against PHEIC declaration.

Conclusion

Striving for more consistency and transparency in EC justifications would benefit future deliberations and provide more understanding and support for the process.
Protocol for a realist review of General Practitioners’ Role in Advancing Practice in Care Homes (GRAPE study)
Authors: Gordon Adam L , Devi Reena , Williams Christopher , Goodman Claire , Sartain Kathleen , Chadborn Neil H
Published: June 2020

Introduction

Older people who live in care homes have a high level of need with complex health conditions. In addition to providing medical care to residents, general practitioners (GPs) play a role as gatekeeper for access to services, as well as leadership within healthcare provision. This review will describe how GPs were involved in initiatives to change arrangements of healthcare services in order to improve quality and experience of care.

Methods and analysis

Following RAMESES quality and publication guidelines standards, we will proceed with realist review to develop theories of how GPs work with care home staff to bring about improvements. We identify when improvement in outcomes does not occur and why this may be the case. The first stage will include interviews with GPs to ask their views on improvement in care homes. These interviews will enable development of initial theories and give direction for the literature searches. In the second stage, we will use iterative literature searches to add depth and context to the early theories; databases will include Medline, Embase, CINAHL, PsycINFO and ASSIA. In stage 3, evidence that is judged as rigorous and relevant will be used to test the initial theories, and through the process, refine the theory statements. In the final stage, we will synthesise findings and provide recommendations for practice and policy-making.

During the review, we will invite a context expert group to reflect on our findings. This group will have expertise in current trends in primary care and the care home sector both in UK and internationally.

Ethics and dissemination

The study was approved by University of Nottingham Faculty of Medicine and Health Sciences Research Ethics Committee: 354-1907. Findings will be shared through stakeholder networks, published in National Institute for Health Research journal and submitted for peer-reviewed journal publication.
The ethics of state-sponsored and clinical promotion of long-acting reversible contraception
Authors: Wale Jeffrey , Rowlands Sam
Published: June 2020

Objectives

To review ethical aspects of the promotion and provision of long-acting reversible contraception (LARC). Specifically, to examine (1) the tension between informational exchange and the active promotion of LARC methods to new and existing contraceptive users by healthcare professionals; and (2) the distinct ethical issues arising from the promotion of LARC methods by state-sponsored actors and healthcare professionals.

Methods

Narrative review and ethical analysis.

Findings

There is an ethical difference between raising awareness/informational provision and actively promoting or prioritising specific contraceptive methods. It matters whether the policy choice is made, or the promotional activity about contraception is undertaken, by individual healthcare professionals at a local level or by more remote state-sponsored actors, because the relationship between the promoter and the (potential) contraceptive user is of a different kind. Imposing a dual responsibility upon healthcare professionals for raising awareness/informational exchange and the active promotion of LARC creates an unnecessary tension and barrier for the delivery of patient-centred care.

Conclusions

This review highlights the need for ethical reflection on the central role of the promoting agent and the distinction between facilitating informational awareness and active promotion of LARC. LARC methods should not be prioritised in isolation and without regard to the wider implications of public promotion. A balanced narrative and information-sharing programme that respects the individual interests of each contraceptive user is called for, especially in direct professional/service user relationships. No assumption should be made that user decision-making will necessarily be determined and influenced solely by the relative effectiveness of the contraceptive method.
Integrating and maintaining automated external defibrillators and emergency planning in community sport settings: a qualitative case study
Authors: Fortington Lauren V , Bekker Sheree , Finch Caroline F
Published: June 2020

Introduction

A voluntary State Government-led programme in Victoria, Australia ‘Defibrillators for Sporting Clubs and Facilities Program’ ran from 2015 to 2019, broadly aimed at increasing access to automated external defibrillators (AEDs), together with a greater number of community members trained for management of medical emergencies. This study aimed to understand whether participating sport clubs/facilities had successfully integrated an AED and medical planning with other club/facility safety practices, 12 months after delivery of the programme.

Methods

This was a qualitative case study of 14 sport clubs/facilities in Victoria, Australia in 2017, underpinned by the Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework. We conducted observational audits of facilities (to locate AED placement, signage and other relevant location-specific factors) and semi-structured, face-to-face interviews with representatives of the clubs/facilities. Interview questions were designed to determine if and how the related, mandated emergency management programme was adapted for the long term (embedding), whether this aligned to ongoing organisational mission (active engagement), and whether or not it was still ongoing 6 months postinitial implementation (sustainability). Data were evaluated using qualitative descriptive methodology. For reporting, descriptive summaries of the audit were combined with interview data to contextualise and visualise the sport club/facility setting and key results.

Results

Key issues identified were accessibility and visibility of the AED, with inadequate signage and challenges identifying an efficient location for access and storage. Most interviewees reported the AED and training were received with no further actions taken towards safety planning or integration with club/facility practice. Several challenges regarding remaining up to date with training and ensuring required routine checks of the AED take place were also raised.

Conclusions

This study identified several challenges for community sport clubs/facilities in the implementation of an AED and medical planning programme, including where to store the AED, how to make its presence known to the community and how to integrate changes alongside other club/facility practices.
COVID-19 and neurointerventional service worldwide: a survey of the European Society of Minimally Invasive Neurological Therapy (ESMINT), the Society of NeuroInterventional Surgery (SNIS), the Sociedad Iberolatinoamericana de Neuroradiologia Diagnostica y Terapeutica (SILAN), the Society of Vascular and Interventional Neurology (SVIN), and the World Federation of Interventional and Therapeutic Neuroradiology (WFITN)
Authors: Fiehler Jens , Brouwer Patrick , Díaz Carlos , Hirsch Joshua A , Kulcsar Zsolt , Liebeskind David , Linfante Italo , Lylyk Pedro , Mack William J , Milburn James , Nogueira Raul , Orbach Darren B , Pumar José Manuel Manuel , Tanaka Michihiro , Taylor Allan
Published: June 2020

Background

This survey was focused on the provision of neurointerventional services, the current practices of managing patients under COVID-19 conditions, and the expectations for the future.

Methods

Invitations for this survey were sent out as a collaborative effort of the European Society of Minimally Invasive Neurological Therapy (ESMINT), the Society of NeuroInterventional Surgery (SNIS), the Sociedad Iberolatinoamericana de Neuroradiologia Diagnostica y Terapeutica (SILAN), the Society of Vascular and Interventional Neurology (SVIN), and the World Federation of Interventional and Therapeutic Neuroradiology (WFITN).

Results

Overall, 475 participants from 61 countries responded (six from Africa (1%), 81 from Asia (17%), 156 from Europe (33%), 53 from Latin America (11%), and 172 from North America (11%)). The majority of participants (96%) reported being able to provide emergency services, though 26% of these reported limited resources. A decrease in emergency procedures was reported by 69% of participants (52% in ischemic and hemorrhagic stroke, 11% ischemic, and 6% hemorrhagic stroke alone). Only 4% reported an increase in emergency cases. The emerging need for social distancing and the rapid adoption of remote communication was reflected in the interest in establishing case discussion forums (43%), general online forums (37%), and access to angio video streaming for live mentoring and support (33%).

Conclusion

Neurointerventional emergency services are available in almost all centers, while the number of emergency patients is markedly decreased. Half of the participants have abandoned neurointerventions in non-emergent situations. There are considerable variations in the management of neurointerventions and in the expectations for the future.
Association between bacterial homoplastic variants and radiological pathology in tuberculosis
Authors: Grandjean Louis , Monteserin Joha , Gilman Robert , Pauschardt Julia , Rokadiya Sakib , Bonilla Cesar , Ritacco Viviana , Vidal Julia Rios , Parkhill Julian , Peacock Sharon , Moore David AJ , Balloux Francois
Published: June 2020

Background

Understanding how pathogen genetic factors contribute to pathology in TB could enable tailored treatments to the most pathogenic and infectious strains. New strategies are needed to control drug-resistant TB, which requires longer and costlier treatment. We hypothesised that the severity of radiological pathology on the chest radiograph in TB disease was associated with variants arising independently, multiple times (homoplasies) in theMycobacterium tuberculosisgenome.

Methods

We performed whole genome sequencing (Illumina HiSeq2000 platform) onM. tuberculosisisolates from 103 patients with drug-resistant TB in Lima between 2010 and 2013. Variables including age, sex, HIV status, previous TB disease and the percentage of lung involvement on the pretreatment chest radiograph were collected from health posts of the national TB programme. Genomic variants were identified using standard pipelines.

Results

Two mutations were significantly associated with more widespread radiological pathology in a multivariable regression model controlling for confounding variables (Rv2828c.141, RR 1.3, 95% CI 1.21 to 1.39, p<0.01; rpoC.1040 95% CI 1.77 to 2.16, RR 1.9, p<0.01). The rpoB.450 mutation was associated with less extensive radiological pathology (RR 0.81, 95% CI 0.69 to 0.94, p=0.03), suggestive of a bacterial fitness cost for this mutation in vivo. Patients with a previous episode of TB disease and those between 10 and 30 years of age also had significantly increased radiological pathology.

Conclusions

This study is the first to compare theM. tuberculosisgenome to radiological pathology on the chest radiograph. We identified two variants significantly positively associated with more widespread radiological pathology and one with reduced pathology. Prospective studies are warranted to determine whether mutations associated with increased pathology also predict the spread of drug-resistant TB.
Perceived risk of electronic cigarettes compared with combustible cigarettes: direct versus indirect questioning
Authors: Churchill Victoria , Nyman Amy L , Weaver Scott R , Yang Bo , Huang Jidong , Popova Lucy
Published: June 2020

Introduction

Tobacco companies claim that a large proportion of the population perceives potential modified risk tobacco products as equally or more harmful than cigarettes, and argue misperceptions need to be corrected using modified risk claims. However, the studies they cite predominantly use one specific measurement of comparative risk. We analysed a representative sample of US adult smokers and non-smokers to examine whether the proportion who report e-cigarettes as less harmful than regular cigarettes differs depending on how the comparative risk questions were presented.

Methods

We analysed data from the 2017 Tobacco Products and Risk Perceptions Survey. Comparative risk of cigarettes and e-cigarettes was measured in two ways: direct (single question) and indirect (by measuring perceived risk of both in separate questions and then subtracting the scores from each other).

Results

When asked to compare harms of e-cigarettes and cigarettes directly (single question), 33.9% of participants identified e-cigarettes as less harmful than cigarettes, 36.4% reported equal harm, 4.3% said e-cigarettes were more harmful and 25.3% said ‘I don’t know’. When asked indirectly (separate questions), 42.1% identified e-cigarettes as less harmful than cigarettes, 23.8% said they were of equal harm, 7.1% perceived e-cigarettes to be more harmful and 27.1% did not know.

Conclusion

Our study offers evidence to suggest the need to use both direct and indirect risk questions when assessing the public’s perceptions of harms associated with novel tobacco products.
Quantifying the association of low-intensity and late initiation of tobacco smoking with total and cause-specific mortality in Asia
Authors: Yang Jae Jeong , Yu Danxia , Shu Xiao-Ou , Freedman Neal D , Wen Wanqing , Rahman Shafiur , Abe Sarah K , Saito Eiko , Gupta Prakash C , He Jiang , Tsugane Shoichiro , Gao Yu-Tang , Xiang Yong-Bing , Yuan Jian-Min , Tomata Yasutake , Tsuji Ichiro , Sugawara Yumi , Matsuo Keitaro , Ahn Yoon-Ok , Park Sue K , Chen Yu , Pan Wen-Harn , Pednekar Mangesh , Gu Dongfeng , Sawada Norie , Cai Hui , Li Hong-Lan , Koh Woon-Puay , Wang Renwei , Zhang Shu , Kanemura Seiki , Ito Hidemi , Shin Myung-Hee , Wu Pei-Ei , Yoo Keun-Young , Ahsan Habibul , Chia Kee Seng , Boffetta Paolo , Inoue Manami , Kang Daehee , Potter John D , Zheng Wei
Published: June 2020

Background

Little is known about the health harms associated with low-intensity smoking in Asians who, on average, smoke fewer cigarettes and start smoking at a later age than their Western counterparts.

Methods

In this pooled analysis of 738 013 Asians from 16 prospective cohorts, we quantified the associations of low-intensity (<5 cigarettes/day) and late initiation (≥35 years) of smoking with mortality outcomes. HRs and 95% CIs were estimated for each cohort by Cox regression. Cohort-specific HRs were pooled using random-effects meta-analysis.

Findings

During a mean follow-up of 11.3 years, 92 068 deaths were ascertained. Compared with never smokers, current smokers who consumed <5 cigarettes/day or started smoking after age 35 years had a 16%–41% increased risk of all-cause, cardiovascular disease (CVD), respiratory disease mortality and a >twofold risk of lung cancer mortality. Furthermore, current smokers who started smoking after age 35 and smoked <5 cigarettes/day had significantly elevated risks of all-cause (HRs (95% CIs)=1.14 (1.05 to 1.23)), CVD (1.27 (1.08 to 1.49)) and respiratory disease (1.54 (1.17 to 2.01)) mortality. Even smokers who smoked <5 cigarettes/day but quit smoking before the age of 45 years had a 16% elevated risk of all-cause mortality; however, the risk declined further with increasing duration of abstinence.

Conclusions

Our study showed that smokers who smoked a small number of cigarettes or started smoking later in life also experienced significantly elevated all-cause and major cause-specific mortality but benefited from cessation. There is no safe way to smoke—not smoking is always the best choice.
Cooling of dark-matter admixed neutron stars with density-dependent equation of state
Authors: Bhat Sajad A. , Paul Avik
Published: June 2020

We propose a dark-matter (DM) admixed density-dependent equation of state where the fermionic DM interacts with the nucleons via Higgs portal. Presence of DM can hardly influence the particle distribution inside neutron star (NS) but can significantly affect the structure as well as equation of state (EOS) of NS. Introduction of DM inside NS softens the equation of state. We explored the effect of variation of DM mass and DM Fermi momentum on the NS EOS. Moreover, DM-Higgs coupling is constrained using dark matter direct detection experiments. Then, we studied cooling of normal NSs using APR and DD2 EOSs and DM admixed NSs using dark-matter modified DD2 with varying DM mass and Fermi momentum. We have done our analysis by considering different NS masses. Also DM mass and DM Fermi momentum are varied for fixed NS mass and DM-Higgs coupling. We calculated the variations of luminosity and temperature of NS with time for all EOSs considered in our work and then compared our calculations with the observed astronomical cooling data of pulsars namely Cas A, RX J0822-43, 1E 1207-52, RX J0002+62, XMMU J17328, PSR B1706-44, Vela, PSR B2334+61, PSR B0656+14, Geminga, PSR B1055-52 and RX J0720.4-3125. It is found that APR EOS agrees well with the pulsar data for lighter and medium mass NSs but cooling is very fast for heavier NS. For DM admixed DD2 EOS, it is found that for all considered NS masses, all chosen DM masses and Fermi momenta agree well with the observational data of PSR B0656+14, Geminga, Vela, PSR B1706-44 and PSR B2334+61. Cooling becomes faster as compared to normal NSs in case of increasing DM mass and Fermi momenta. It is infered from the calculations that if low mass super cold NSs are observed in future that may support the fact that heavier WIMP can be present inside neutron stars.
Quantum wireless network communication based on cluster states
Authors: Yang Yu-Guang , Cao Sheng-Nan , Zhou Yi-Hua , Shi Wei-Min
Published: June 2020

Due to the high security of quantum transmission and the more flexible and economical implementation of wireless communication, quantum wireless network communication attracts lots of attention. Because of the high entanglement persistence and robustness of cluster states against decoherence and loss, we investigate the application of cluster states in quantum wireless network communication (QWNC) and propose several kinds of QWNC schemes based on 1D, 2D and 3D cluster states, respectively. Finally we propose a QWNC scheme under the bilayer quantum network architecture. Comparing with other multi-hop teleportation schemes, it is unnecessary for the intermediate nodes to perform entanglement swapping to establish the required entanglement. The computational complexity is independent of the number of intermediate nodes and cluster states are allocated on demand, thus reducing the computational complexity and resource consumption largely.
Thermodynamics and statistical physics of quasiparticles within the quark–gluon plasma model
Authors: Dzhunushaliev Vladimir , Folomeev Vladimir , Ramazanov Tlekkabul , Kozhamkulov Tolegen
Published: June 2020

We consider thermodynamic properties of a quark–gluon plasma related to quasiparticles having the internal structure. For this purpose, we employ a possible analogy between quantum chromodynamics and non-Abelian Proca-Dirac-Higgs theory. The influence of characteristic sizes of the quasiparticles on such thermodynamic properties of the quark–gluon plasma like the internal energy and pressure is studied. Sizes of the quasiparticles are taken into account in the spirit of the van der Waals equation but we take into consideration that the quasiparticles have different sizes, and the average value of these sizes depends on temperature. It is shown that this results in a change in the internal energy and pressure of the quark–gluon plasma. Also, we show that, when the temperature increases, the average value of characteristic sizes of the quasiparticles increases as well. This leads to the occurrence of a phase transition at the temperature at which the volume occupied by the quasiparticles is compared with the volume occupied by the plasma.
First-principles study on the thermodynamic, mechanical and magnetic properties of the Fe-N phases
Authors: Li Zhi , Zhao Zhen , Shi Tong-Tong , Zang Xi-Min
Published: June 2020

To clear the intermetallic Fe-N phases, how to effect the strength and magnetic features of iron nitrides thin films, the thermodynamic, mechanical and magnetic attributes of the Fe-N phases have been calculated at Perdew, Burke and Enzerhof (PBE) level. The results show that the [Formula: see text] and [Formula: see text] phases are more stable than the other considered Fe-N phases by the formation energies. [Formula: see text] and [Formula: see text] phases are metastable at 0 K, which can be further decomposed into other more stable phases with temperature decreasing, i.e., [Formula: see text] and [Formula: see text]. [Formula: see text] is the only brittle phase, while [Formula: see text] is the most ductile phase. The [Formula: see text] possesses the highest thermal conductivity by Debye temperatures. The [Formula: see text] possesses the highest anisotropic behavior by [Formula: see text], [Formula: see text] and [Formula: see text] values. The [Formula: see text] and FeN phases possess higher average magnetic moments (MM) than their neighbors. The [Formula: see text] has stronger ionic bond by Mülliken population analysis.
Wave propagation and spiral wave formation in a Hindmarsh–Rose neuron model with fractional-order threshold memristor synaps
Authors: Rajagopal Karthikeyan , Karthikeyan Anitha , Jafari Sajad , Parastesh Fatemeh , Volos Christos , Hussain Iqtadar
Published: June 2020

In this paper, a modified Hindmarsh–Rose neuron model is presented, which has a fractional-order threshold magnetic flux. The dynamics of the model is investigated by bifurcation diagrams and Lyapunov exponents in two cases of presence and absence of the external electromagnetic induction. Then the emergence of the spiral waves in the network of the proposed model is studied. To find the effects of different factors on the formation and destruction of spiral waves, the external current, the coupling strength and the external stimuli amplitude are varied. It is observed that all of these parameters have significant impacts on the spiral waves. Furthermore, the external electromagnetic induction influences the existence of spiral waves in specific external current values.
Insecurity of Jiang et al.’s quantum cryptography protocol
Authors: Gao Gan , Wang Yue , Cui Xue-Ying , Zhou Zhen-Gen
Published: June 2020

Recently, Jiang et al. proposed a quantum cryptography protocol [Mod. Phys. Lett. B 32 (2018) 1850125] which can implement the equal exchange of secret information between the two parties with the help of semi-trusted third party. Here, it will be shown that the protocol is insecure and has the drawback of information leakage.
A novel piezoelectric hysteresis modeling method combining LSTM and NARX neural networks
Authors: Wang Geng , Yao Xuemin , Cui Jianjun , Yan Yonggang , Dai Jun , Zhao Wu
Published: June 2020

In order to study the hysteresis nonlinear characteristics of piezoelectric actuators, a novel hybrid modeling method based on Long-Short-Term Memory (LSTM) and Nonlinear autoregressive with external input (NARX) neural networks is proposed. First, the input–output curve between the applied voltage and the produced angle of a piezoelectric tip/tilt mirror is measured. Second, two hysteresis models named LSTM and NARX neural networks were, respectively, established mathematically, and then were tested and verified experimentally. Third, a novel adaptive weighted hybrid hysteresis model which combines LSTM and NARX neural networks was proposed through analyzing and comparing the unique characteristics of the above two hysteresis models. The proposed hybrid model combines LSTM’s ability to approximate nonlinear static hysteresis and NARX’s high dynamic-fitting ability. Experimental results show that the RMS errors of the hybrid model are smaller than those of LSTM model and NARX model. That is to say, the proposed hybrid model has a relatively high accuracy. Compared with the traditional differential equation-based and operator-based hysteresis models, the presented hybrid neural network method has higher flexibility and accuracy in modeling performance, and is a more promising method for modeling piezoelectric hysteresis.
Structures, electronic and magnetic properties of transition metal atoms encapsulated in Si12C12 cage
Authors: Li Zhi , Zhao Zhen , Shao Tao-Tao
Published: June 2020

The structures, stability, electronic and magnetic properties of the TM@Si[Formula: see text]C[Formula: see text] clusters have been calculated by using PBE functional. The results indicate that only for the TM@Si[Formula: see text]C[Formula: see text] (TM[Formula: see text]Zn, Y, Ag, Cd, Lu, Au and Hg) clusters, TM atoms are nearly located at the center of the Si[Formula: see text]C[Formula: see text] cages. As for other TM@Si[Formula: see text]C[Formula: see text] clusters, TM atoms approach one side of the Si[Formula: see text]C[Formula: see text] cages. The structural stability of the Ti@Si[Formula: see text]C[Formula: see text], Ti@Si[Formula: see text]C[Formula: see text], Zr@Si[Formula: see text]C[Formula: see text], Nb@Si[Formula: see text]C[Formula: see text], Hf@Si[Formula: see text]C[Formula: see text], Ta@Si[Formula: see text]C[Formula: see text], W@Si[Formula: see text]C[Formula: see text] and Os@Si[Formula: see text]C[Formula: see text] is higher than that of the Si[Formula: see text]C[Formula: see text] cages. All TM@Si[Formula: see text]C[Formula: see text] clusters display covalent bond characteristics. The spins of the TM atoms in the TM@Si[Formula: see text]C[Formula: see text] cages are dramatically quenched and only the V@Si[Formula: see text]C[Formula: see text] and Cr@Si[Formula: see text]C[Formula: see text] clusters remain −1.474 [Formula: see text] and 1.638 [Formula: see text], respectively.
Study of warm inflationary models and their parameter estimation from CMB
Authors: Arya Richa , Rangarajan Raghavan
Published: June 2020

Warm inflation is a natural and well-motivated description of cosmic inflation which accounts for the inflaton dissipation and radiation production during the inflationary phase, neglected in the standard cold description. It results in crucial differences in the imprints on the Cosmic Microwave Background (CMB) radiation from the standard cold description. In this study, we consider warm inflation models with [Formula: see text] and [Formula: see text] potentials and estimate their model parameters consistent with CMB using the CosmoMC numerical code. These models are characterized by the inflaton self coupling, [Formula: see text], and the dissipation parameter, [Formula: see text], due to the inflaton’s dissipation into the other fields. Therefore, information about these physical parameters is essential from the perspective of the model building. In our analysis, we also calculate the spectral index, [Formula: see text], and the tensor-to-scalar ratio, [Formula: see text], for the mean values of the parameters and show that for the weak dissipative regime, [Formula: see text], is within the sensitivity of the next generation CMB polarization experiments, which is an important observational test for these models.
EFFECT OF LOW-ENERGY OXYGEN ION BEAM TREATMENT ON THE STRUCTURAL AND PHYSICAL PROPERTIES OF ZnO THIN FILMS
Authors: ABDEL-GALIL A. , ATTA A. , BALBOUL M. R.
Published: June 2020

In this paper, we report the influence of low-energy oxygen ion irradiation with fluence ranging from [Formula: see text][Formula: see text][Formula: see text] to [Formula: see text][Formula: see text][Formula: see text] on the structural, optical, and electrical properties of fresh and annealed (400∘C, 3[Formula: see text]h) zinc oxide (ZnO) thin films. These films were grown on soda-lime glass (SLG) substrates using the spin-coating method as a low-cost depositing technique. X-ray diffraction (XRD) study showed the formation of the hexagonal phase of ZnO thin films with preferred orientation along the (002) plane. The crystallite size for fresh and annealed ZnO thin films was in nanoscale and it increased with the annealing temperature. Also, the crystallite size increased with the ion beam irradiation fluence in the case of annealed ZnO films, while it slightly decreased for the fresh ZnO films. The transmittance and absorbance spectra for the ZnO films were investigated in a wide wavelength range. The optical bandgap was specified by using Tauc’s relation. The electrical properties of the ZnO films (fresh and annealed at 400∘C for 3[Formula: see text]h) were studied before and after the oxygen ion beam irradiation. Also, the dielectric properties were investigated with respect to frequency at different ion beam irradiation fluences. The comprehensive results showed the dielectric and optical properties are improved due to the induced conductive networks by oxygen ion irradiation.
Financial Crisis and Earnings Management Under U.S. GAAP and IFRS
Authors: Vichitsarawong Thanyaluk , Eng Li Li
Published: June 2020

This paper examines the effects of the global financial crisis of 2008 on real and accrual-based earnings management activities of foreign companies listed in the United States as American Depositary Receipts (ADRs). The ADR firms are classified according to whether they report under U.S. Generally Accepted Accounting Principles (GAAP) or International Financial Reporting Standards (IFRS). Accrual-based earnings management is measured using the absolute value of performance-matched discretionary accruals. We also use the positive and negative values of performance-matched discretionary accruals to examine income-increasing and income-decreasing earnings management, respectively. Real earnings management proxies are measured using performance-matched measures of the abnormal levels of cash flow from operations, production costs, and discretionary expenses. In summary, our findings indicate no difference in accrual-based earnings management for ADRs reporting under IFRS and U.S. GAAP but suggest that ADRs reporting under IFRS are more likely to manage earnings using income-decreasing discretionary accruals and aggregate real earnings management than ADRs reporting under U.S. GAAP during the financial crisis.
Hydrodynamic Response Analysis of Combined Spar Wind Turbine and Fish Cage for Offshore Fish Farms
Authors: Chu Y. I. , Wang C. M.
Published: June 2020

This paper is concerned with the hydrodynamic response of a novel offshore fish farm that combines a floating spar wind turbine and a fish cage (named as COSPAR for brevity). The open net steel cage is octagonal in shape with a partially porous wave fence at its top end to attenuate wave energy for a calm fish farming environment as well as to keep predators out. The deep draught spar is made from concrete for its bottom half and from steel for its top half. The spar carries a control unit and a 1[Formula: see text]MW wind turbine that provides the required power to operate the offshore salmon fish farm. The COSPAR fish cage has four catenary chains as mooring lines attached to mid length of the spar (outside the fish cage) so as to mitigate tension force in the mooring lines and to reduce the benthic footprint. ANSYS Design Modeler and Aqwa are used to perform the hydrodynamic response analysis of free-floating condition of COSPAR in the frequency domain and coupled analysis involving COSPAR and the mooring lines in the frequency domain and time domain. Environmental conditions, representing 5-year, 20-year and 50-year wave return periods with a constant current flow at an exposed fish farming site in Storm Bay of Tasmania, Australia, are adopted for the analyses. A comparison study is made against having a floating fish cage only (i.e. without the bottom half concrete of the spar) with four catenary chains attached to side vertical columns of the cage so that the fish cage behaves like a semi-submersible cage. Based on the comparison study, the COSPAR fish cage shows enhanced hydrodynamic responses in the following respects: (1) more stable motion responses in heave and pitch against wave and current forces, (2) less susceptible to the viscous damping when it is assumed by a linearized drag force of Morison elements in the frequency domain and (3) reduction of tension forces in the mooring lines. Interestingly, the pitch motion response of COSPAR fish cage in the frequency domain is in close agreement with the time domain result due to its greater pitching stiffness that reduces nonlinear effects from viscous drag and mooring interaction.
A Multiple Variational Iteration Method for Nonlinear Two-Point Boundary Value Problems with Nonlinear Conditions
Authors: Ghorbani Asghar , Wazwaz Abdul-Majid
Published: June 2020

A multiple variational iteration method (VIM) is proposed to effectively solve the second-order nonlinear two-point boundary value problems. For problems where convergence speed of the original VIM is slow or the original method is divergent, the multiple VIM method (MVIM) presented in this paper can readily improve the rate of convergence.
On minus quotients of ideal class groups of cyclotomic fields
Authors: Fujii Satoshi
Published: June 2020

Let [Formula: see text] be the minus quotient of the ideal class group of the [Formula: see text]th cyclotomic field. In this paper, first, we show that each finite abelian group appears as a subgroup of [Formula: see text] for some [Formula: see text]. Second, we show that, for all pairs of integers [Formula: see text] and [Formula: see text] with [Formula: see text], the kernel of the lifting map [Formula: see text] is contained in the [Formula: see text]-torsion [Formula: see text] of [Formula: see text]. Such an evaluation of the exponent is an individuality of cyclotomic fields.
Chapter 10 Mineral resources and prospectivity of the ultramafic rocks of New Caledonia
Authors: Maurizot P. , Sevin B. , Lesimple S. , Bailly L. , Iseppi M. , Robineau B.
Published: June 2020

The main metallic mineral resources of New Caledonia are hosted by the obducted Peridotite Nappe. Ni, Co, Cr and the Pt group elements (PGEs) are specific to this ultramafic terrane. Cr, as podiform chromitite in the uppermost mantle, is the only hypogene metal mined economically in the past. The largest chromitite deposits are located in the lherzolitic Tiébaghi Massif. Supergene Ni and Co deposits are concentrated by the tropical climate that has prevailed since the Miocene. New Caledonian lateritic Ni deposits account for 10% of the global Ni resources. Hydrous Mg silicate and oxide types coexist in a single deposit. A local genetic model based on geomorphological evolution is proposed. Sc is a prospective resource associated with these supergene deposits. The PGEs are a prospective resource associated with chromite, with potential in the hypogene, supergene and fluvio-littoral domains. Pt and Pd are the most significant elements. The transition zone between the upper mantle and crustal cumulates constitutes a regional Pt–Pd-enriched horizon. The concentrations are related to small disseminated chromite lenses in a pyroxene-rich lithology. The PGEs are concentrated in weathering profiles. The value of chromite-rich sands as placers or sand beach deposits might be enhanced by the occurrences of PGEs.
Chapter 5 The Eocene Subduction–Obduction Complex of New Caledonia
Authors: Maurizot P. , Cluzel D. , Patriat M. , Collot J. , Iseppi M. , Lesimple S. , Secchiari A. , Bosch D. , Montanini A. , Macera P. , Davies H. L.
Published: June 2020

Convergence and subduction started in the Late Paleocene, to the east of New Caledonia in the South Loyalty Basin/Loyalty Basin, leading to the formation of the Subduction–Obduction Complex of Grande Terre. Convergence during the Eocene consumed the oceanic South Loyalty Basin and the northeasternmost margin of Zealandia (the Norfolk Ridge). The attempted subduction of the Norfolk Ridge eventually led to the end-Eocene obduction. Intra-oceanic subduction started in the South Loyalty Basin, as indicated by high-temperature amphibolite (56 Ma), boninite and adakite series dykes (55–50 Ma) and changes in the sedimentation regime (55 Ma). The South Loyalty Basin and its margin were dragged to a maximum depth of 70 km, forming the high-pressure–low-temperature Pouébo Terrane and the Diahot–Panié Metamorphic Complex, before being exhumed at 38–34 Ma. The obduction complex was formed by the stacking from NE to SW of several allochthonous units over autochthonous Zealandia, including the Montagnes Blanches Nappe (Norfolk Ridge crust), the Poya Terrane (the crust of the South Loyalty Basin) and the Peridotite Nappe (the mantle lithosphere of the Loyalty Basin). A model of continental subduction accepted by most researchers is proposed and discussed. Offshore continuations and comparable units in Papua New Guinea and New Zealand are presented.
A Simple and Approximately Optimal Mechanism for an Additive Buyer
Authors: Babaioff Moshe , Immorlica Nicole , Lucier Brendan , Weinberg S. Matthew
Published: June 2020

We consider a monopolist seller with
n
heterogeneous items, facing a single buyer. The buyer has a value for each item drawn independently according to (non-identical) distributions, and her value for a set of items is additive. The seller aims to maximize his revenue.

We suggest using the
a priori better
of two simple pricing methods:
selling the items separately
, each at its optimal price, and
bundling together
, in which the entire set of items is sold as one bundle at its optimal price. We show that for any distribution, this mechanism achieves a constant-factor approximation to the optimal revenue. Beyond its simplicity, this is the first computationally tractable mechanism to obtain a constant-factor approximation for this multi-parameter problem. We additionally discuss extensions to multiple buyers and to valuations that are correlated across items.
The Role of Diet in Cancer Prevention and Chemotherapy Efficacy
Authors: Mittelman Steven D.
Published: June 2020

Despite great advances in treatment, cancer remains a leading cause of death worldwide. Diet can greatly impact health, while caloric restriction and fasting have putative benefits for disease prevention and longevity. Strong epidemiological associations exist between obesity and cancer, whereas healthy diets can reduce cancer risk. However, less is known about how diet might impact cancer once it has been diagnosed and particularly how diet can impact cancer treatment. In the present review, we discuss the links between obesity, diet, and cancer. We explore potential mechanisms by which diet can improve cancer outcomes, including through hormonal, metabolic, and immune/inflammatory effects, and present the limited clinical research that has been published in this arena. Though data are sparse, diet intervention may reduce toxicity, improve chemotherapy efficacy, and lower the risk of long-term complications in cancer patients. Thus, it is important that we understand and expand the science of this important but complex adjunctive cancer treatment strategy.
Uncertainty in Population Forecasts for the Twenty-First Century
Authors: Keilman Nico
Published: June 2020

The aim of this article is to review a number of issues related to uncertain population forecasts, with a focus on world population. Why are these forecasts uncertain? Population forecasters traditionally follow two approaches when dealing with this uncertainty, namely scenarios (forecast variants) and probabilistic forecasts. Early probabilistic population forecast models were based upon a frequentist approach, whereas current ones are of the Bayesian type. I evaluate the scenario approach versus the probabilistic approach and conclude that the latter is preferred. Finally, forecasts of resources need not only population input, but also input on future numbers of households. While methods for computing probabilistic country-specific household forecasts have been known for some time, how to compute such forecasts for the whole world is yet an unexplored issue.