bluuebunny/crossref_metadata_2025 huggingface dataset:
Vegetation response to climate warming across the forest–tundra ecotone: species‐dependent upward movement
Authors: Løkken Jørn Olav , Evju Marianne , Söderström Lars , Hofgaard Annika
Published: May 2020

Questions

Rising temperatures are predicted to cause upward shifts and reorganisation of mountain vegetation. This study analyses how field layer vegetation across the forest–tundra ecotone has responded over a 22‐year period. Main questions are: (a) have vegetation composition, richness and diversity changed; (b) have abundance of functional plant groups and individual species changed; and (c) which environmental factors regulate vegetation distribution and composition?

Location

Central Norway.

Methods

The study uses vascular plant species recordings and environmental data from permanent 1 m × 1 m quadrats (n = 266), established in 1994 and revisited in 2016, along transects from forest to high alpine areas (750–1,500 m a.s.l.). Changes in vegetation composition (species and functional group levels) and influence of environmental factors are analysed using ordination and mixed‐effect models.

Results

Ordination shows an overall upward vegetation movement corresponding to 0.5 ± 0.1 m/y, and compositional homogenisation across the ecotone over time. Changes at species and functional group levels vary across the ecotone. Species richness and diversity increase over time due mainly to an increase of herbs and graminoids in the forested part of the ecotone. Evergreen woody species increase in abundance across the entire ecotone and most strongly above the forest. Deciduous woody species abundance is stable at group level but shows large variation at species level. Species‐level responses deviate from group‐level responses in all functional groups. Vegetation distribution and composition are environmentally explained by altitudinal distance to the treeline and microtopography.

Conclusions

Our results show how increased temperature impacts vegetation movements and reorganisation through mainly species‐specific responses with low within‐functional‐group coherency. The apparent upward shift is moderate compared to the increase in temperature over the study period, but larger than in similar studies, although grazing pressure might co‐control change rate. Species‐specific responses and response rates highlight the need for detailed empirical data to predict and understand vegetation responses in a warming climate.
Cost and cost‐effectiveness of a simplified treatment model with direct‐acting antivirals for chronic hepatitis C in Cambodia
Authors: Walker Josephine G. , Mafirakureva Nyashadzaishe , Iwamoto Momoko , Campbell Linda , Kim Chamroeun San , Hastings Reuben A. , Doussett Jean‐Philippe , Le Paih Mickael , Balkan Suna , Marquardt Tonia , Maman David , Loarec Anne , Coast Joanna , Vickerman Peter
Published: May 2020

Background & Aims

In 2016, Médecins Sans Frontières established the first general population Hepatitis C virus (HCV) screening and treatment site in Cambodia, offering free direct‐acting antiviral (DAA) treatment. This study analysed the cost‐effectiveness of this intervention.

Methods

Costs, quality adjusted life years (QALYs) and cost‐effectiveness of the intervention were projected with a Markov model over a lifetime horizon, discounted at 3%/year. Patient‐level resource‐use and outcome data, treatment costs, costs of HCV‐related healthcare and EQ‐5D‐5L health states were collected from an observational cohort study evaluating the effectiveness of DAA treatment under full and simplified models of care compared to no treatment; other model parameters were derived from literature. Incremental cost‐effectiveness ratios (cost/QALY gained) were compared to an opportunity cost‐based willingness‐to‐pay threshold for Cambodia ($248/QALY).

Results

The total cost of testing and treatment per patient for the full model of care was $925(IQR $668‐1631), reducing to $376(IQR $344‐422) for the simplified model of care. EQ‐5D‐5L values varied by fibrosis stage: decompensated cirrhosis had the lowest value, values increased during and following treatment. The simplified model of care was cost saving compared to no treatment, while the full model of care, although cost‐effective compared to no treatment ($187/QALY), cost an additional $14 485/QALY compared to the simplified model, above the willingness‐to‐pay threshold for Cambodia. This result is robust to variation in parameters.

Conclusions

The simplified model of care was cost saving compared to no treatment, emphasizing the importance of simplifying pathways of care for improving access to HCV treatment in low‐resource settings.
Phenotypic/genotypic sex mismatches and temperature‐dependent sex determination in a wild population of an Old World atherinid, the cobaltcap silverside Hypoatherina tsurugae
Authors: Miyoshi Kaho , Hattori Ricardo S. , Strüssmann Carlos A. , Yokota Masashi , Yamamoto Yoji
Published: May 2020

Several New World atheriniforms have been recognized as temperature‐dependent sex determined (TSD) and yet possess a genotypic sex determinant (amhy) which is primarily functional at mid‐range temperatures. In contrast, little is known about the sex determination in Old World atheriniforms, even though such knowledge is crucial to understand the evolution of sex determination mechanisms in fishes and to model the effects of global warming and climate change on their populations. This study examined the effects of water temperature on sex determination of an Old World atheriniform, the cobaltcap silverside Hypoatherina tsurugae, in which we recently described an amhy homologue. We first assessed the occurrence of phenotypic/genotypic sex mismatches in wild specimens from Tokyo Bay for three years (2014–2016) and used otolith analysis to estimate their birth dates and approximate thermal history during the presumptive period of sex determination. Phenotypic sex ratios became progressively biased towards males (47.3%–78.2%) during the period and were associated with year‐to‐year increases in the frequency of XX‐males (7.3%–52.0%) and decreases in XY/YY‐females (14.5%–0%). The breeding season had similar length but was delayed by about 1 month per year between 2014 and 2016, causing larvae to experience higher temperatures during the period of sex determination from year to year. Larval rearing experiments confirmed increased likelihood of feminization and masculinization at low and high temperatures, respectively. The results suggest that cobaltcap silverside has TSD, or more specifically the coexistence of genotypic and environmental sex determinants, and that it affects sex ratios in wild populations.
Cerebrospinal fluid oxidative stress markers in Alzheimer's disease
Authors: Sakakibara Ryuji , Kawai Takayuki
Published: May 2020

Oxidative stress has a significant impact on neurodegenerative diseases. The present paper reviewed the role of oxidative stress in disease progression of Alzheimer's disease (AD) and measurement of the oxidative stress markers in cerebrospinal fluid (CSF) in AD in vivo. Oxidative stress measurement in CSF in AD provides knowledge of underlying pathophysiology, to be a counterpart of oxidative stress neuroimaging, and to help differentiating AD from other neurodegenerative diseases. In addition, these findings warrant future studies to see whether antioxidant intervention might help preventing progression of neurodegenerative diseases including AD.
Coronaviridae—Old friends, new enemy!
Authors: Leao Jair Carneiro , Gusmao Teresa Paula de Lima , Zarzar Adriana Machado , Leao Filho Jair Carneiro , Barkokebas Santos de Faria Andreza , Morais Silva Igor Henrique , Gueiros Luiz Alcino Monteiro , Robinson Narendran Andrew , Porter Stephen , Carvalho Alessandra de Albuquerque Tavares
Published: May 2020

Coronaviridae is a family of single‐stranded positive enveloped RNA viruses. This article aimed to review the history of these viruses in the last 60 years since their discovery to understand what lessons can be learned from the past. A review of the PubMed database was carried out, describing taxonomy, classification, virology, genetic recombination, host adaptation, and main symptoms related to each type of virus. SARS‐CoV‐2 is responsible for the ongoing global pandemic, and SARS‐CoV and MERS‐CoV were responsible for causing severe respiratory illness and regional epidemics in the past while the four other strains of CoVs (229‐E OC43, NL63, and HKU1) circulate worldwide and normally only cause mild upper respiratory tract infections. Given the enormous diversity of coronavirus viruses in wildlife and their continuous evolution and adaptation to humans, future outbreaks would undoubtedly occur. Restricting or banning all trade in wild animals in wet markets would be a necessary measure to reduce future zoonotic infections.
Prolonged Analgesia by Spinal Cord Stimulation Following a Spinal Injury Associated With Activation of Adult Neural Progenitors
Authors: Sun Liting , Fleetwood‐Walker Sue , Mitchell Rory , Joosten Elbert A. , Cheung Chi Wai
Published: May 2020

Objectives

Responses of spinal progenitors to spinal cord stimulation (SCS) following spinal cord injury (SCI) in rats were assessed to reveal their potential contribution to SCS‐induced analgesia.

Methods

Spinal epidural electrodes were implanted in rats at T12 rostral to a quadrant dorsal horn injury at T13. Further groups additionally received either a microlesion to the dorsolateral funiculus (DLF) or gabapentin (10 mg/kg). SCS was performed at 25 Hz for 10 minutes on day 4 (early SCS) and at 10 Hz for 10 minutes on day 8 (late SCS) after injury. Paw withdrawal threshold (PWT) was measured before injury, 30 minutes before or after SCS, and before cull on day 14, followed by immunostaining assessment.

Results

Paw withdrawal thresholds in uninjured animals (51.0 ± 4.0 g) were markedly reduced after SCI (17.3 ± 2.2 g). This was significantly increased by early SCS (38.5 ± 5.2 g, P < 0.01) and further enhanced by late SCS (50.9 ± 1.9 g, P < 0.01) over 6 days. Numbers of neural progenitors expressing nestin, Sox2, and doublecortin (DCX) in the spinal dorsal horn were increased 6 days after SCS by 6‐fold, 2‐fold, and 2.5‐fold, respectively (P < 0.05 to 0.01). The elevated PWT evoked by SCS was abolished by DLF microlesions (48.9 ± 2.6 g vs. 19.0 ± 3.9 g, P < 0.01) and the number of nestin‐positive cells was reduced to the level without SCS (P < 0.05). Gabapentin enhanced late SCS‐induced analgesia from 37.0 ± 3.9 g to 54.0 ± 0.8 g (P < 0.01) and increased gamma‐aminobutyric acid (GABA)‐ergic neuronal marker vesicular GABA transporter–positive newborn cells 2‐fold (P < 0.01).

Conclusions

Spinal progenitor cells appear to be activated by SCS via descending pathways, which may be enhanced by gabapentin and potentially contributes to relief of SCI‐induced neuropathic pain.
Linear censored quantile regression: A novel minimum‐distance approach
Authors: De Backer Mickaël , El Ghouch Anouar , Van Keilegom Ingrid
Published: May 2020

In this article, we investigate a new procedure for the estimation of a linear quantile regression with possibly right‐censored responses. Contrary to the main literature on the subject, we propose in this context to circumvent the formulation of conditional quantiles through the so‐called “check” loss function that stems from the influential work of Koenker and Bassett (1978). Instead, our suggestion is here to estimate the quantile coefficients by minimizing an alternative measure of distance. In fact, our approach could be qualified as a generalization in a parametric regression framework of the technique consisting in inverting the conditional distribution of the response given the covariates. This is motivated by the knowledge that the main literature for censored data already relies on some nonparametric conditional distribution estimation as well. The ideas of effective dimension reduction are then exploited in order to accommodate for higher dimensional settings as well in this context. Extensive numerical results then suggest that such an approach provides a strongly competitive procedure to the classical approaches based on the check function, in fact both for complete and censored observations. From a theoretical prospect, both consistency and asymptotic normality of the proposed estimator for linear regression are obtained under classical regularity conditions. As a by‐product, several asymptotic results on some “double‐kernel” version of the conditional Kaplan–Meier distribution estimator based on effective dimension reduction, and its corresponding density estimator, are also obtained and may be of interest on their own. A brief application of our procedure to quasar data then serves to further highlight the relevance of the latter for quantile regression estimation with censored data.
Comparison of balance performance between masters Olympic weightlifters and runners
Authors: Riemann Bryan L. , Mercado Mara , Erickson Kayleigh , Grosicki Gregory J.
Published: May 2020

Balance disorders are a common problem among older adults that greatly increase susceptibility for falls and fractures. Aerobically trained older (masters) athletes tend to exhibit superior balance abilities compared to that of healthy age‐matched counterparts. Olympic weightlifting involves tremendous power production and motor skill coordination throughout the body which may prompt unique sensory information acquisition and integration adaptations. The purpose of this investigation was to compare a modified clinical test of sensory interaction and balance performance between middle‐aged (~40‐60 years) masters Olympic weightlifters (OWL, n = 48) and runners (RUN, n = 42). Average mediolateral center of pressure velocity (MLCPV) was computed during completion of 2 double leg trials (30‐s) completed on firm (FI) and foam (FO) surfaces with eyes open (EO) and eyes closed (EC). While there were no significant differences between the groups for either the EO‐FI (P = .143, d = 0.34) or EO‐FO (P = .209, d = 0.26), the OWL demonstrated significantly better balance (lower MLCPV) than the RUN for both the EC‐FI (P = .009, d = 0.59) and EC‐FO (P = .001, d = 0.70). The most salient result of this investigation was the identification of better balance performance by the OWL, particularly when visual inputs were unavailable (ie, EC), compared to the RUN. These results suggest that Olympic weightlifting may provide a superior training stimulus for somatosensory and vestibular function compared to running in middle‐aged adults, a benefit that may help to offset archetypal age‐related balance deficits.
Binding affinities of 438 HLA proteins to complete proteomes of seven pandemic viruses and distributions of strongest and weakest HLA peptide binders in populations worldwide
Authors: Barquera Rodrigo , Collen Evelyn , Di Da , Buhler Stéphane , Teixeira João , Llamas Bastien , Nunes José M. , Sanchez‐Mazas Alicia
Published: May 2020

We report detailed peptide‐binding affinities between 438 HLA Class I and Class II proteins and complete proteomes of seven pandemic human viruses, including coronaviruses, influenza viruses and HIV‐1. We contrast these affinities with HLA allele frequencies across hundreds of human populations worldwide. Statistical modelling shows that peptide‐binding affinities classified into four distinct categories depend on the HLA locus but that the type of virus is only a weak predictor, except in the case of HIV‐1. Among the strong HLA binders (IC50 ≤ 50), we uncovered 16 alleles (the top ones being A*02:02, B*15:03 and DRB1*01:02) binding more than 1% of peptides derived from all viruses, 9 (top ones including HLA‐A*68:01, B*15:25, C*03:02 and DRB1*07:01) binding all viruses except HIV‐1, and 15 (top ones A*02:01 and C*14:02) only binding coronaviruses. The frequencies of strongest and weakest HLA peptide binders differ significantly among populations from different geographic regions. In particular, Indigenous peoples of America show both higher frequencies of strongest and lower frequencies of weakest HLA binders. As many HLA proteins are found to be strong binders of peptides derived from distinct viral families, and are hence promiscuous (or generalist), we discuss this result in relation to possible signatures of natural selection on HLA promiscuous alleles due to past pathogenic infections. Our findings are highly relevant for both evolutionary genetics and the development of vaccine therapies. However they should not lead to forget that individual resistance and vulnerability to diseases go beyond the sole HLA allelic affinity and depend on multiple, complex and often unknown biological, environmental and other variables.
Trichodysplasia spinulosa: Case reports and review of literature
Authors: Jose Aju , Dad Taimur , Strand Andrew , Tse Julie Y. , Plotnikova Natalia , Boucher Helen W. , Sarnak Mark J. , Gilbert Scott J. , Goyal Nitender
Published: May 2020

Trichodysplasia spinulosa (TS) is a rare skin condition caused by trichodysplasia spinulosa‐associated polyomavirus (TSPyV). It affects immunosuppressed patients, and <50 cases have been reported. The majority of these cases are seen in solid organ transplant recipients. TS often poses a diagnostic and therapeutic challenge because of its rarity and resemblance with other skin conditions. Several forms of treatment are usually tried prior to establishing a definitive diagnosis. Oral valganciclovir and topical cidofovir have been found to give the best results and hence are the most commonly used agents once the diagnosis is established. Here, we present two cases with a review of literature of TS in solid organ transplant recipients, focusing on time to develop the condition post‐transplant, immunosuppression regimen used, and treatment initiated both before and after a definitive diagnosis.
Occurrence of polycyclic aromatic hydrocarbons in water and sediment samples from KwaZulu Natal Province, South Africa
Authors: Ngubo Ayanda , Mahlambi Precious N. , Ojwach Stephen O.
Published: May 2020

Solid‐phase extraction (SPE) and ultrasonic extraction (UE) techniques followed by Gas Chromatography‐Mass Spectrometry (GC‐MS) have been modified for qualitative and quantitative analysis of polycyclic aromatic hydrocarbons (PAHs) in water and sediment samples. Percentage recoveries of PAHs ranged from 85 to 121% in water and 82 to 117% in sediment samples. The limits of detection (LOD) and limits of quantification (LOQ) ranged from 0.02 to 0.2 and 0.05 to 0.5 µg/L for SPE while for UE, they were between 0.008–0.09 and 0.02–0.30 µg/kg, respectively. The concentration levels of PAHs (naphthalene, acenaphthene, acenaphthylene, fluorine, anthracene, phenanthrene and pyrene) detected in water samples were 0.071–2.7, 2.0–10.4 and 2.5–3.5 µg/L in wastewater, river water, and dam water, respectively. In sediment samples, concentration levels of PAHs were between 2.8–42.0 and 2.8–3.9 µg/kg, in river and dam sediment, respectively.
Experimental analysis of saline diffusion during saltwater freezing for desalination purposes
Authors: Castillo‐Téllez Beatriz , Pilatowsky Figueroa Isaac , Allaf Karim , Marzoug Rachid , Castillo Téllez Margarita
Published: May 2020

The Freezing Melting (F/M) is considered one of the most sustainable desalination techniques in terms of energy consumption compared with commercial desalination. However, it presents some problems, especially salt trapping in the ice. In this paper, an experimental analysis is carried out to achieve a better understanding of saline ions displacement observed during the freezing of saline water. Different sizes, freezing temperatures and, geometries are tested using the F/M progressive desalination. It is found that salt diffusion improves with increasing the container length. Moreover, for all container geometries, the saline ion diffusion direction is from the bottom to the top of the formed ice. Furthermore, at low freezing temperature (−8°C), it is possible to purify 78.8 % of the frozen water, obtaining an easy‐to‐separate brine.
Supplemental Material: River discharge variability as the link between climate and fluvial fan formation
Authors: Hansford Mark , Plink-Björklund Piret
Published: June 2020

Tables S1 and S2, and Data Set S3 (kmz file)
Oral manifestations of Alagille syndrome
Authors: Bonnet Anne-Laure , Greset Victor , Davit-Beal Tiphaine
Published: May 2020

Alagille syndrome (AGS) is a multisystem disorder classically involving liver and heart failure, characteristic vertebral and facial features and ocular abnormalities. AGS is caused by heterozygous mutations in JAG1 or NOTCH2, with variable phenotype penetrance. We report two cases of AGS in children with tooth defects characterised by green discolouration and hypomineralisation. The role of hyperbilirubinaemia (HB) in this atypical colour, a classical feature of AGS, has been well described. However, it does not totally explain the dental phenotype. As JAG1 and NOTCH2 mutations can affect bone development and considering common physiological pathways between bone and tooth mineralisation, both mutations could participate in this unusual dental phenotype. The role of HB and genetics in the development of the dental phenotype of AGS is discussed in two prototypical cases. Future research should focus on the underlying genetic component of tooth abnormalities.
Choroidal luminal and stromal areas and choriocapillaris perfusion are
characterised by a non-linear quadratic relation in healthy eyes
Authors: Borrelli Enrico , Gabela Maria Cristina , Sacconi Riccardo , Querques Lea , Vella Giovanna , Zuccaro Biancamaria , Gelormini Francesco , Bandello Francesco , Querques Giuseppe
Published: June 2020

Purpose

To assess the associations among different optical coherence tomography
(OCT) structural and angiography quantitative metrics used to characterise the
choroid in healthy subjects.

Methods

In this cross-sectional study, macular structural OCT and OCT angiography
(OCTA) images were acquired from healthy subjects. The main outcome measures
were: (i) choriocapillaris (CC) flow deficits percentage (FD%), (ii) choroidal
luminal (LA) and stromal (SA) areas and (iii) choroidal vascularity index
(CVI), which was calculated as the LA divided by the total choroidal area.
These measurements were generated using previously published algorithms and
were separately computed in the foveal and extrafoveal regions.

Results

Eighty-five eyes from 85 subjects (44 males, 41 females) were included in
the analysis. Mean±SD age was 47.9±22.4 years (range: 19.0 to 85.0 years).
Linear regression analysis displayed no significant associations between CC FD%
and other parameters (LA, SA and CVI). Importantly, non-linear regression
analysis showed that the relations of LA and SA to CC FD% were all best fitted
by a quadratic function. Compared with the linear models, the use of the
quadratic function allowed a relative increase in the R2
coefficients. No significant non-linear associations were found between CC FD%
and CVI.

Conclusion

Based on our models, changes in the luminal and stromal areas in the
choroid lead to an initial increase in CC perfusion. Subsequently, further
increases in LA and SA amounts are accompanied by a progressive increment in CC
FD%.
The Stanford Hall consensus statement for post-COVID-19 rehabilitation
Authors: Barker-Davies Robert M , O"Sullivan Oliver , Senaratne Kahawalage Pumi Prathima , Baker Polly , Cranley Mark , Dharm-Datta Shreshth , Ellis Henrietta , Goodall Duncan , Gough Michael , Lewis Sarah , Norman Jonathan , Papadopoulou Theodora , Roscoe David , Sherwood Daniel , Turner Philippa , Walker Tammy , Mistlin Alan , Phillip Rhodri , Nicol Alastair M , Bennett Alexander N , Bahadur Sardar
Published: May 2020

The highly infectious and pathogenic novel coronavirus (CoV), severe acute respiratory syndrome (SARS)-CoV-2, has emerged causing a global pandemic. Although COVID-19 predominantly affects the respiratory system, evidence indicates a multisystem disease which is frequently severe and often results in death. Long-term sequelae of COVID-19 are unknown, but evidence from previous CoV outbreaks demonstrates impaired pulmonary and physical function, reduced quality of life and emotional distress. Many COVID-19 survivors who require critical care may develop psychological, physical and cognitive impairments. There is a clear need for guidance on the rehabilitation of COVID-19 survivors. This consensus statement was developed by an expert panel in the fields of rehabilitation, sport and exercise medicine (SEM), rheumatology, psychiatry, general practice, psychology and specialist pain, working at the Defence Medical Rehabilitation Centre, Stanford Hall, UK. Seven teams appraised evidence for the following domains relating to COVID-19 rehabilitation requirements: pulmonary, cardiac, SEM, psychological, musculoskeletal, neurorehabilitation and general medical. A chair combined recommendations generated within teams. A writing committee prepared the consensus statement in accordance with the appraisal of guidelines research and evaluation criteria, grading all recommendations with levels of evidence. Authors scored their level of agreement with each recommendation on a scale of 0–10. Substantial agreement (range 7.5–10) was reached for 36 recommendations following a chaired agreement meeting that was attended by all authors. This consensus statement provides an overarching framework assimilating evidence and likely requirements of multidisciplinary rehabilitation post COVID-19 illness, for a target population of active individuals, including military personnel and athletes.
Electrostatics and self-force in asymptotically flat cylindrical wormholes
Authors: Rubín de Celis E. , Simeone C.
Published: June 2020

The problem of the electrostatics in conical wormholes is revisited, now improving the background geometries with asymptotical flatness. The electric self-force on a point charge placed at different regions in the spacetime of a conical thin-shell wormhole connecting flat outer submanifolds is obtained and compared with the results of previous works. The study is also carried out in terms of a previously introduced analogy in which the effect of the matter shells on the electric field is reproduced by non-gravitating layers of charge located on the boundary surfaces. Besides, a better insight on the physical effects of a non trivial geometry is obtained by means of a further analysis of the electric fluxes across the wormhole throat and at both spatial infinities. It is found that the throat is traversed by a non-arbitrary and finite electric flux determined by the global topology, which is proportional to the charge of the source, and is characteristic of the asymptotically flat cylindrical wormholes regardless of the details of the throat geometry.
Entire functions with prescribed singular values
Authors: Boc Thaler Luka
Published: May 2020

We introduce a new class of entire functions [Formula: see text] which consists of all [Formula: see text] for which there exists a sequence [Formula: see text] and a sequence [Formula: see text] satisfying [Formula: see text] for all [Formula: see text]. This new class is closed under the composition and it is dense in the space of all nonvanishing entire functions. We prove that every closed set [Formula: see text] containing the origin and at least one more point is the set of singular values of some locally univalent function in [Formula: see text], hence, this new class has nontrivial intersection with both the Speiser class and the Eremenko–Lyubich class of entire functions. As a consequence, we provide a new proof of an old result by Heins which states that every closed set [Formula: see text] is the set of singular values of some locally univalent entire function. The novelty of our construction is that these functions are obtained as a uniform limit of a sequence of entire functions, the process under which the set of singular values is not stable. Finally, we show that the class [Formula: see text] contains functions with an empty Fatou set and also functions whose Fatou set is nonempty.
The optimal synchronizability of complex networks with saturated coupling strength
Authors: Huang Chen , Lu Xinbiao , Zhou Jun , Qin Buzhi
Published: May 2020

For networks with fixed network topology, when the total coupling strength between nodes is limited and the coupling strength between nodes is saturated, the global optimization algorithms including genetic algorithm (GA) and particle swarm optimization (PSO) algorithm are used to adjust the coupling strength between nodes to improve the synchronizability of the network, respectively. Simulation results show that in WS small-world network, when the edge betweenness centrality of the edge is large, the coupling strength of the edge after optimization is greater. Furthermore, compared with GA, PSO has better performance.
A Noise Reduction 12-bit 125-MSPS SAR ADC with Modified Asynchronous Logic Regulation Technique
Authors: Xu Daiguo , Yang Han , Sheng Xing , Sun Ting , Chen Guangbing , Xu Shiliu , Zhu Can , Wang Jianan , Fu Dongbin
Published: May 2020

This paper presents noise reduction and modified asynchronous logic regulation techniques used in successive approximation register (SAR) analog-to-digital converter (ADC). With a transconductance enhanced structure, noise reduction is provided in the dynamic comparator. The input referred noise of the proposed comparator is about 165[Formula: see text][Formula: see text]V rms at 60∘C (typical corner). An enhanced-positive-feedback loop is introduced to reduce the regeneration delay of the comparator. In addition, a modified asynchronous logic regulation technique is exhibited, a clock with adaptable delay is driving the comparator in approximation phase. Consequently, the settling accuracy of DAC (Digital-to-Analog Converter) is enough and the conversion speed of SAR ADC is increased without any redundant cycles. To demonstrate the proposed techniques, a design of SAR ADC is fabricated in 65-nm CMOS technology, consuming 4[Formula: see text]mW from 1.2[Formula: see text]V power supply with a [Formula: see text][Formula: see text]dB and [Formula: see text][Formula: see text]dB. The proposed ADC core occupies an active area of 0.048[Formula: see text]mm2, and the corresponding FoM is 27.2[Formula: see text]fJ/conversion-step at Nyquist rate.
VLSI Design of a Fast One-Stage Independent Component Extracting System Based on ICA-R Algorithm
Authors: Li Zunchao , Feng Lichen , Zhang Jian , Li Xinyi
Published: May 2020

Independent component analysis (ICA) is an efficient blind source separation technique, but the extracted independent components are randomly permuted in classic ICA algorithms, and subsequent identification is required to find the desired component. Such a two-stage method causes inefficiency. By utilizing the prior information, ICA with reference (ICA-R) algorithm can extract the desired source signal in one stage without subsequent processing. There are many theoretical extensions on ICA-R, but few hardware implementations can be found. Therefore, the efficient VLSI design of a fast one-stage independent component extracting system based on ICA-R algorithm is presented in this paper. The proposed system consists of Preprocess module and Iteration module, which are designed highly parallel and pipelined to accelerate the extraction process. The designed system is implemented in Kintex-7 FPGA, and its performance is verified using synthesized signal. Experiment results show that the presented system can extract the desired components in one stage without subsequent identification, and the highly parallel circuit structure of the system speeds up the component extracting process by [Formula: see text] compared to software implementation.
Gravitational waves in modified Gauss–Bonnet gravity
Authors: Inagaki Tomohiro , Taniguchi Masahiko
Published: May 2020

We study the gravitational waves (GWs) in modified Gauss–Bonnet gravity. Applying the metric perturbation around a cosmological background, we obtain explicit expressions for the wave equations. It is shown that the speed of the traceless mode is equal to the speed of light. An additional massive scalar mode appears in the propagation of the GWs. To find phenomena beyond the general relativity, the scalar mode mass is calculated as a function of the background curvature in some typical models.
Vibrational-rotational spectra of even–even nuclei with quadrupole and octupole deformations
Authors: Nadirbekov M. S. , Kudiratov S. N. , Temirov F. N. , Minkov N.
Published: May 2020

Vibrational-rotation levels of the yrast and first nonyrast alternating-parity bands of the lanthanide [Formula: see text]Nd, [Formula: see text]Sm, [Formula: see text]Gd, [Formula: see text]Er and actinide [Formula: see text]Th, [Formula: see text]U, [Formula: see text]Pu nuclei are studied in the framework of a nonadiabatic collective model of even–even nuclei with quadrupole and octupole deformations. The theoretical spectra are obtained through the use of Gauss and harmonic-oscillator (HO) potentials in the radial part of the Schrödinger equation which is taken in polar coordinates. The change of the surface deformation of the nucleus with the collective excitation energy is taken into account. The [Formula: see text] staggering structure of the yrast alternating-parity bands is also considered. The theoretically obtained energy bands and staggering diagrams are in good agreement with the corresponding experimental data and point out the soft character of the collective quadrupole–octupole deformation mode manifesting in these nuclei.
A REVIEW OF RECENT METHODS FOR TOOL WEAR REDUCTION IN ELECTRICAL DISCHARGE MACHINING
Authors: GILL AMOLJIT SINGH , KUMAR SANJEEV , SINGH JUJHAR , AGGARWAL VIVEK , SHARMA SHUBHAM
Published: May 2020

Electrical discharge machining (EDM) is one of the most explored nonconventional machining processes due to its ability to machine intricate shapes on conductive materials. However, tool wear is one of the major challenges in the EDM process as it directly affects the accuracy of machining, surface roughness, reproduction of geometrical characteristics on the workpiece and cost of the process. Lots of work have been done to minimize the tool wear by improving the discharge conditions by controlling the EDM process parameters, varying the dielectric characteristics, powder-mixed dielectric methods and ultrasonic-assisted methods. However, minimizing the tool wear by the above approaches also constrains the material removal rate from the workpiece and accuracy of the process. This review highlights the efforts done by the researchers to improve tool wear by recently developed techniques or modifications. Researches available in the field of using treated tool electrode, cooled tool electrode, coated tool electrode, noble tool materials and other techniques are highlighted.
SIMULATION OF BORON DIFFUSION IN THE NEAR-SURFACE REGION OF SILICON SUBSTRATE
Authors: VELICHKO O. I.
Published: May 2020

The mechanism of boron-enhanced diffusion from a thin boron layer deposited on the surface in the case of silicon crystal doping is proposed and investigated. It was supposed that lattice contraction occurs in the vicinity of the surface due to the difference between the atomic radii of boron and silicon. This lattice contraction provides a stress-mediated diffusion of silicon self-interstitials from the near-surface region to the bulk of a semiconductor. Due to the stress-mediated diffusion, the near-surface region is depleted of silicon self-interstitials, and simultaneous oversaturation of this species occurs in the bulk. In this way, a strong nonuniform distribution of silicon self-interstitials in the vicinity of the surface is formed without regard to the large migration length of this species. The oversaturation of the bulk of a semiconductor with nonequilibrium self-interstitials allows one to explain the boron-enhanced diffusion of impurity atoms. The strong nonuniform distribution of these point defects also results in a specific form of boron concentration profile in the vicinity of the surface. Good agreement of the calculated boron profile with the experimental data for the entire doped region was obtained within the limit of the proposed model.
MORPHOLOGIES OF SILVER NANOPARTICLES (Ag NPs) SYNTHESIZED BY HYDROTHERMAL AND LASER ABLATION TECHNIQUES
Authors: SHAHID REHANA , KHALID SIDRA , SHAHZADI SHAMAILA
Published: May 2020

Silver nanoparticles (Ag NPs) are prepared using two different techniques namely hydrothermal and laser ablation methods. The purpose of this study is to find a more suitable method to prepare Ag NPs through comparison that can give stable and size-controlled silver nanoparticles. Techniques used for observations are X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). Comparison of results exhibited that hydrothermal process is a more suitable method to prepare silver nanoparticles with smaller uniform size and better yield as compared to laser ablation method. Also, at low temperature, NPs obtained using hydrothermal process provide better control on morphology, high purity and narrow size distribution.
Dynamic Response of a Beam Structure Excited by Sequentially Moving Rigid Bodies
Authors: Gao Hao , Yang Bingen
Published: May 2020

A coupled dynamic system consisting of a supporting beam structure and multiple passing rigid bodies is seen in various engineering applications. The dynamic response of such a coupled system is quite different from that of the beam structure subject to moving loads or moving oscillators. The dynamic interactions between the beam and moving rigid bodies are complicated, mainly because of the time-varying number and locations of contact points between the beam and bodies. Due to lack of an efficient modeling and solution technique, previous studies on these coupled systems have been limited to a beam carrying one or a few moving rigid bodies. As such, dynamic interactions between a supporting structure and arbitrarily many moving rigid bodies have not been well investigated, and parametric resonance induced by a sequence of moving rigid bodies, which has important engineering implications, is missed. In this paper, a new semi-analytical method for modeling and analysis of the above-mentioned coupled systems is developed. The method is based on an extended solution domain, by which the number of degrees of freedom of a coupled system is fixed regardless of the number of contact points between the beam and moving rigid bodies at any given time. This feature allows simple and concise description of flexible–rigid body interactions in modeling, and easy and effective implementation of numerical algorithms in solution. The proposed method provides a useful platform for thorough study of flexible–rigid body interactions and parametric resonance for coupled beam–moving rigid body systems. The accuracy and efficiency of the proposed method in computation is demonstrated in several examples.
Optimal Vibration Control of Membrane Structures with In-Plane Polyvinylidene Fluoride Actuators
Authors: Lu Yifan , Shao Qi , Yang Fei , Yue Honghao , Liu Rongqiang
Published: May 2020

Different kinds of membrane structures have been proposed for future space exploration and earth observation. However, due to the low stiffness, high flexibility, and low damping properties, membrane structures are likely to generate large-amplitude (compared to the thickness) vibrations, which may lead to the degradation of their working performance. In this work, the governing equations are established at first, taking into account the modal control force induced by the polyvinylidene fluoride (PVDF) actuator. The optimal vibration control of the membrane structure is explored subsequently. A square PVDF actuator is attached on the membrane to achieve the vibration suppression. The influence of actuator position and control gains on the vibration control performance are studied. The optimal criteria for actuator placement and energy allocation are developed. Several case studies are numerically simulated to demonstrate the validity of the proposed optimization criteria. The analytical results in this study can serve as guidelines for optimal vibration control of membrane structures. Additionally, the proposed optimization criteria can be applied to active control of different flexible structures.
Full-Space Response Surface Method for Analysis of Structural Reliability
Authors: Yang Lu Feng , Li Zhao Yang , Yu Bo , Li Qiu Sheng
Published: May 2020

In order to improve the computational efficiency of the response surface method (RSM) in analysis of structural reliability, a full-space response surface method (FRSM) is presented in this paper. First, a vector-type response surface is developed by expanding the stochastic nodal displacement vector along the Krylov basis vectors defined by the global stiffness matrix and the force vector. Then the effective collocation points are picked out of the candidate ones according to the linear independence of the combining row vector. Finally, the unknown coefficients of the proposed response surface are determined by means of the regression analysis. Examples show that the proposed FRSM requires much fewer effective collocation points and less times of finite element analysis, achieving much higher computational efficiency by comparing with the traditional RSM.
Generalized right near domains and sharply 2-transitive groups
Authors: Kakkar Vipul , Lal Ramji , Lal Ratan , Yadav Akhilesh Chandra
Published: May 2020

In this paper, we study the generalized right near domains and its relations with sharply [Formula: see text]-transitive groups. We find a necessary and sufficient condition when a generalized right near domain is a field. Also, we have found the isomorphism classes of right near domains in a sharply [Formula: see text]-transitive group.
Optimal Key Generation for Data Sanitization and Restoration of Cloud Data: Future of Financial Cyber Security
Authors: Balashunmugaraja B. , Ganeshbabu T. R.
Published: May 2020

Cloud security in finance is considered as the key importance, taking account of the aspect of critical data stored over cloud spaces within organizations all around the globe. They are chiefly relying on cloud computing to accelerate their business profitability and scale up their business processes with enhanced productivity coming through flexible work environments offered in cloud-run working systems. Hence, there is a prerequisite to contemplate cloud security in the entire financial service sector. Moreover, the main issue challenged by privacy and security is the presence of diverse chances to attack the sensitive data by cloud operators, which leads to double the user’s anxiety on the stored data. For solving this problem, the main intent of this paper is to develop an intelligent privacy preservation approach for data stored in the cloud sector, mainly the financial data. The proposed privacy preservation model involves two main phases: (a) data sanitization and (b) data restoration. In the sanitization process, the sensitive data is hidden, which prevents sensitive information from leaking on the cloud side. Further, the normal as well as the sensitive data is stored in a cloud environment. For the sanitization process, a key should be generated that depends on the new meta-heuristic algorithm called crossover improved-lion algorithm (CI-LA), which is inspired by the lion’s unique social behavior. During data restoration, the same key should be used for effectively restoring the original data. Here, the optimal key generation is done in such a way that the objective model involves the degree of modification, hiding rate, and information preservation rate, which effectively enhance the cyber security performance in the cloud.
Improving Human Performance in Dynamic Tasks with Debriefing-Based Interactive Learning Environments: An Empirical Investigation
Authors: Qudrat-Ullah Hassan
Published: May 2020

Dynamic tasks are pervasive in organizational decision making. Improving managerial performance in dynamic tasks is an ongoing research endeavor. We report a laboratory experiment in which participants managed a dynamic task by playing the roles of fishing fleet managers. The two experimental groups used a computer simulation-based interactive learning environment (ILE) with an outcome-oriented debriefing and a process-oriented debriefing. To assess the users’ learning and performance, a comprehensive five-dimensional model was used to evaluate subjects’ task performance, decision time, decision strategy, structural knowledge, and heuristics knowledge. The results showed that process-oriented debriefing improved subjects’ task performance, helped users gain task knowledge, develop heuristics, and adapt to systematic-variable consistent strategies. Contrary to our hypothesis, the process-oriented debriefing group did not use less decision time. In contrast to the cost-benefit approach to decision making, a relatively more systematic effort is needed to perform better in dynamic tasks such as fisheries management.
A New Adaptive Weighted Deep Forest and Its Modifications
Authors: Utkin Lev V. , Konstantinov Andrei V. , Chukanov Viacheslav S. , Meldo Anna A.
Published: May 2020

A new adaptive weighted deep forest algorithm which can be viewed as a modification of the confidence screening mechanism is proposed. The main idea underlying the algorithm is based on adaptive weigting of every training instance at each cascade level of the deep forest. The confidence screening mechanism for the deep forest proposed by Pang et al., strictly removes instances from training and testing processes to simplify the whole algorithm in accordance with the obtained random forest class probability distributions. This strict removal may lead to a very small number of training instances at the next levels of the deep forest cascade. The presented modification is more flexible and assigns weights to instances in order to differentiate their use in building decision trees at every level of the deep forest cascade. It overcomes the main disadvantage of the confidence screening mechanism. The proposed modification is similar to the AdaBoost algorithm to some extent. Numerical experiments illustrate the outperformance of the proposed modification in comparison with the original deep forest. It is also illustrated how the proposed algorithm can be extended for solving the transfer learning and distance metric learning problems.
A hybrid OFDM–CDMA-based robust image watermarking technique
Authors: Waqas Ghulam Jilani , Ahmad Ishtiaq , Samee Muhammad Kashif , Khan Muhammad Nasir , Raza Ali
Published: May 2020

Digital watermarking is a process of embedding hidden information called watermark into different kinds of media objects. It uses basic modulation, multiplexing and transform techniques of communication for hiding information. Traditional techniques used are least significant bit (LSB) modification, discrete cosine transform (DCT), discrete wavelet transform (DWT), discrete Fourier transform (DFT), code division multiple access (CDMA) or a combination of these. Among these, CDMA is the most robust against different attacks except geometric attacks. This paper proposes a blind and highly robust watermarking technique by utilizing the basis of orthogonal frequency division multiplexing (OFDM) and CDMA communication system. In this scheme, the insertion process starts by taking DFT of host images, permuting the watermark bits in randomized manner and recording them in a seed as a key. Then PSK modulation follows inverse DFT (IDFT) that gives watermark information as OFDM symbols. These symbols are spread using spreading codes and then arithmetically added to the host image. Finally, scheme applies inverse DCT (IDCT) to get watermarked host images. The simulation results of the proposed scheme are compared with CDMA-based scheme in DCT domain. The results show that the robustness of the proposed scheme is higher than the existing scheme for non-geometric attacks.