bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematic Patterns in Land Precipitation Due to Convection in Neighboring Islands in the Maritime Continent During MJO Propagation
Authors: Tan Haochen , Ray Pallav , Barrett Bradford , Dudhia Jimy , Moncrieff Mitchell W.
Published: January 2021

The land‐sea contrast in the Maritime Continent (MC) has been found to influence the Madden–Julian Oscillation (MJO). However, the specific contribution from individual islands to the precipitation over the surrounding islands during MJO propagation is not well known. We found that when an island is removed in the presence of lower‐tropospheric westerlies, precipitation increases over islands that are located to its east due to the strengthening of the westerlies. Frictional convergence of the stronger westerlies, aided by Coriolis, leads to an increase in vertical advection of moisture and precipitation over an island located to the east. On the other hand, the reduced heating over the removed island reduces the westerlies and precipitation to the west of the removed island and is consistent with the response of large‐scale circulation to tropical heating. During background easterlies prior to MJO arrival, a systematic decrease in precipitation was found in the surrounding islands to the west side of the removed island. But, on the eastern side of the removed island, no systematic change in precipitation was found. The results imply that changes in large‐scale circulation in response to convection (or a lack thereof) over a removed island may significantly influence precipitation in the neighboring islands. Therefore, biases in model precipitation over an island in the MC may arise from bias in precipitation over a neighboring island. Moreover, the presence of different island chains in the MC has led to a more conducive environment for more overall precipitation over the islands in the MC.
A specific neural substrate predicting current and future impulsivity in young adults
Authors: Steele J. Scott , Bertocci Michele , Eckstrand Kristen , Chase Henry W. , Stiffler Richelle , Aslam Haris , Lockovich Jeanette , Bebko Genna , Phillips Mary L.
Published: January 2021

Impulsivity (rash action with deleterious outcomes) is common to many psychiatric disorders. While some studies indicate altered amygdala and prefrontal cortical (PFC) activity associated with impulsivity, it remains unclear whether these patterns of neural activity are specific to impulsivity or common to a range of affective and anxiety symptoms. To elucidate neural markers specific to impulsivity, we aimed to differentiate patterns of amygdala–PFC activity and functional connectivity associated with impulsivity from those associated with affective and anxiety symptoms, and identify measures of this circuitry predicting future worsening of impulsivity. Using a face emotion processing task that reliably activates amygdala–PFC circuitry, neural activity and connectivity were assessed in a transdiagnostically-recruited sample of young adults, including healthy (N = 47) and treatment-seeking individuals (N = 67). Relationships were examined between neural measures and impulsivity, anhedonia, and affective and anxiety symptoms at baseline (N = 114), and at 6 months post scan (N = 30). Impulsivity, particularly negative urgency and lack of perseverance, was related to greater amygdala activity (beta = 0.82, p = 0.003; beta = 0.68, p = 0.004; respectively) and lower amygdala–medial PFC functional connectivity (voxels = 60, tpeak = 4.45, pFWE = 0.017; voxels = 335, tpeak = 5.26, pFWE = 0.001; respectively) to facial fear. Left vlPFC, but not amygdala, activity to facial anger was inversely associated with mania/hypomania (beta = −2.08, p = 0.018). Impulsivity 6 months later was predicted by amygdala activity to facial sadness (beta = 0.50, p = 0.017). There were no other significant relationships between neural activity and 6-month anhedonia, affective, and anxiety symptoms. Our findings are the first to associate amygdala–PFC activity and functional connectivity with impulsivity in a large, transdiagnostic sample, providing neural targets for future interventions to reduce predisposition to impulsivity and related future mental health problems in young adults.
Off-treatment bone mineral density changes in postmenopausal women receiving anastrozole for 5 years: 7-year results from the IBIS-II prevention trial
Authors: Sestak Ivana , Blake Glen , Patel Raj , Cuzick Jack , Howell Anthony , Coleman Robert , Eastell Richard
Published: January 2021

Background

Anastrozole has been associated with substantial accelerated bone mineral density (BMD) loss during active treatment.

Methods

One thousand four hundred and ten women were included in a BMD substudy and stratified into three strata according to their baseline T-score at spine or femoral neck. The primary objective of this analysis was to investigate whether DXA BMD at the spine and hip changed two years after treatment cessation (between years 5 and 7) in those who did not receive risedronate.

Results

Five- and seven-year BMD data were available for a total of 528 women who did not receive risedronate. In women with normal BMD at baseline, an increase in BMD at the lumbar spine after anastrozole withdrawal was observed 1.25% (95% CI 0.73 to 1.77) (P = 0.0004), which was larger than in those on placebo (0.14% (−0.29 to 0.56))). At the hip, BMD remained unchanged between years 5 and 7 for those previously on anastrozole but continued to a decrease in those who had been randomised to placebo (−1.35% (−1.70 to −0.98)).

Conclusions

These are the first results reporting BMD changes after stopping anastrozole in a breast cancer prevention setting. Our results show that the negative effects of anastrozole on BMD in the preventive setting are partially reversible.
Tumor exosome promotes Th17 cell differentiation by transmitting the lncRNA CRNDE-h in colorectal cancer
Authors: Sun Junfeng , Jia Haowei , Bao Xingqi , Wu Yue , Zhu Tianyu , Li Ruixin , Zhao Hongchao
Published: January 2021

The T helper 17 (Th17) cells in tumor microenvironment play an important role in colorectal cancer (CRC) progression. This study investigated the mechanism of Th17 cell differentiation in CRC with a focus on the role of tumor exosome-transmitted long noncoding RNA (lncRNA). Exosomes were isolated from the CRC cells and serum of CRC patients. The role and mechanism of the lncRNA CRNDE-h transmitted by CRC exosomes in Th17 cell differentiation were assessed by using various molecular biological methods. The serum exosomal CRNDE-h level was positively correlated with the proportion of Th17 cells in the tumor-infiltrating T cells in CRC patients. CRC exosomes contained abundant CRNDE-h and transmitted them to CD4+ T cells to increase the Th17 cell proportion, RORγt expression, and IL-17 promoter activity. The underlying mechanism is that, CRNDE-h bound to the PPXY motif of RORγt and impeded the ubiquitination and degradation of RORγt by inhibiting its binding with the E3 ubiquitin ligase Itch. The in vivo experiments confirmed that the targeted silence of CRNDE-h in CD4+ T cells attenuated the CRC tumor growth in mice. The present findings demonstrated that the tumor exosome transmitted CRNDE-h promoted Th17 cell differentiation by inhibiting the Itch-mediated ubiquitination and degradation of RORγt in CRC, expanding our understanding of Th17 cell differentiation in CRC.
Semi-parametric empirical Bayes factor for genome-wide association studies
Authors: Morisawa Junji , Otani Takahiro , Nishino Jo , Emoto Ryo , Takahashi Kunihiko , Matsui Shigeyuki
Published: January 2021

Bayes factor analysis has the attractive property of accommodating the risks of both false negatives and false positives when identifying susceptibility gene variants in genome-wide association studies (GWASs). For a particular SNP, the critical aspect of this analysis is that it incorporates the probability of obtaining the observed value of a statistic on disease association under the alternative hypotheses of non-null association. An approximate Bayes factor (ABF) was proposed by Wakefield (Genetic Epidemiology 2009;33:79–86) based on a normal prior for the underlying effect-size distribution. However, misspecification of the prior can lead to failure in incorporating the probability under the alternative hypothesis. In this paper, we propose a semi-parametric, empirical Bayes factor (SP-EBF) based on a nonparametric effect-size distribution estimated from the data. Analysis of several GWAS datasets revealed the presence of substantial numbers of SNPs with small effect sizes, and the SP-EBF attributed much greater significance to such SNPs than the ABF. Overall, the SP-EBF incorporates an effect-size distribution that is estimated from the data, and it has the potential to improve the accuracy of Bayes factor analysis in GWASs.
The double-sided effects of Mycobacterium Bovis bacillus Calmette–Guérin vaccine
Authors: Li Junli , Zhan Lingjun , Qin Chuan
Published: January 2021

Bacillus Calmette–Guérin (BCG), the only vaccine proven to be effective against tuberculosis (TB), is the most commonly used vaccine globally. In addition to its effects on mycobacterial diseases, an increasing amount of epidemiological and experimental evidence accumulated since its introduction in 1921 has shown that BCG also exerts non-specific effects against a number of diseases, such as non-mycobacterial infections, allergies and certain malignancies. Recent Corona Virus Disease 2019 (COVID-19) outbreak has put BCG, a classic vaccine with significant non-specific protection, into the spotlight again. This literature review briefly covers the diverse facets of BCG vaccine, providing new perspectives in terms of specific and non-specific protection mechanisms of this old, multifaceted, and controversial vaccine.
Pandanus nutshell generates a palaeoprecipitation record for human occupation at Madjedbebe, northern Australia
Authors: Florin S. Anna , Roberts Patrick , Marwick Ben , Patton Nicholas R. , Shulmeister James , Lovelock Catherine E. , Barry Linda A. , Hua Quan , Nango May , Djandjomerr Djaykuk , Fullagar Richard , Wallis Lynley A. , Fairbairn Andrew S. , Clarkson Chris
Published: January 2021

Little is known about the Pleistocene climatic context of northern Australia at the time of early human settlement. Here we generate a palaeoprecipitation proxy using stable carbon isotope analysis of modern and archaeological pandanus nutshell from Madjedbebe, Australia’s oldest known archaeological site. We document fluctuations in precipitation over the last 65,000 years and identify periods of lower precipitation during the penultimate and last glacial stages, Marine Isotope Stages 4 and 2. However, the lowest effective annual precipitation is recorded at the present time. Periods of lower precipitation, including the earliest phase of occupation, correspond with peaks in exotic stone raw materials and artefact discard at the site. This pattern is interpreted as suggesting increased group mobility and intensified use of the region during drier periods.
Genome-resolved metagenomics reveals site-specific diversity of episymbiotic CPR bacteria and DPANN archaea in groundwater ecosystems
Authors: He Christine , Keren Ray , Whittaker Michael L. , Farag Ibrahim F. , Doudna Jennifer A. , Cate Jamie H. D. , Banfield Jillian F.
Published: January 2021

Candidate phyla radiation (CPR) bacteria and DPANN archaea are unisolated, small-celled symbionts that are often detected in groundwater. The effects of groundwater geochemistry on the abundance, distribution, taxonomic diversity and host association of CPR bacteria and DPANN archaea has not been studied. Here, we performed genome-resolved metagenomic analysis of one agricultural and seven pristine groundwater microbial communities and recovered 746 CPR and DPANN genomes in total. The pristine sites, which serve as local sources of drinking water, contained up to 31% CPR bacteria and 4% DPANN archaea. We observed little species-level overlap of metagenome-assembled genomes (MAGs) across the groundwater sites, indicating that CPR and DPANN communities may be differentiated according to physicochemical conditions and host populations. Cryogenic transmission electron microscopy imaging and genomic analyses enabled us to identify CPR and DPANN lineages that reproducibly attach to host cells and showed that the growth of CPR bacteria seems to be stimulated by attachment to host-cell surfaces. Our analysis reveals site-specific diversity of CPR bacteria and DPANN archaea that coexist with diverse hosts in groundwater aquifers. Given that CPR and DPANN organisms have been identified in human microbiomes and their presence is correlated with diseases such as periodontitis, our findings are relevant to considerations of drinking water quality and human health.
Cross-country evidence on the association between contact tracing and COVID-19 case fatality rates
Authors: Yalaman Abdullah , Basbug Gokce , Elgin Ceyhun , Galvani Alison P.
Published: January 2021

The coronavirus disease (COVID-19) outbreak has killed over a million people since its emergence in late 2019. However, there has been substantial variability in the policies and intensity of diagnostic efforts between countries. In this paper, we quantitatively evaluate the association between national contact tracing policies and case fatality rates of COVID-19 in 138 countries. Our regression analyses indicate that countries that implement comprehensive contact tracing have significantly lower case fatality rates. This association of contact tracing policy and case fatality rates is robust in our longitudinal regression models, even after controlling for the number of tests conducted and non-pharmaceutical control measures adopted by governments. Our results suggest that comprehensive contact tracing is instrumental not only to curtailing transmission but also to reducing case fatality rates. Contact tracing achieves the early detection and isolation of secondary cases which are particularly important given that the peak in infectiousness occurs during the presymptomatic phase. The early detection achieved by contact tracing accelerates the rate at which infected individuals receive medical care they need to maximize their chance of recovery. In addition, the combination of reduced transmission and more rapid recovery diminishes the burden on the healthcare system which in turn ensures that the resources remain available for individuals who do become infected.
Modelling the impact of tailored behavioural interventions on chlamydia transmission
Authors: van Wees Daphne A. , den Daas Chantal , Kretzschmar Mirjam E. E. , Heijne Janneke C. M.
Published: January 2021

Behavioural interventions tailored to psychological characteristics of an individual can effectively achieve risk-reducing behaviour. The impact of tailored interventions on population-level chlamydia prevalence is unknown. We aimed to assess the impact on overall chlamydia prevalence five years after the introduction of an intervention aimed at increasing self-efficacy, social norms, attitudes and intentions towards condom use (i.e., condom intervention), and an intervention aimed at increasing health goals and decreasing impulsiveness (i.e., impulsiveness intervention). A pair model, informed by longitudinal psychological and behavioural data of young heterosexuals visiting sexual health centers, with susceptible-infected-susceptible structure was developed. The intervention effect was defined as an increased proportion of each subgroup moving to the desired subgroup (i.e., lower risk subgroup). Interventions tailored to subgroup-specific characteristics, assuming differential intervention effects in each subgroup, more effectively reduced overall chlamydia prevalence compared to non-tailored interventions. The most effective intervention was the tailored condom intervention, which was assumed to result in a relative reduction in chlamydia prevalence of 18% versus 12% in the non-tailored scenario. Thus, it is important to assess multiple psychological and behavioural characteristics of individuals. Tailored interventions may be more successful in achieving risk-reducing behaviour, and consequently, reduce chlamydia prevalence more effectively.
Restoration of breathing after opioid overdose and spinal cord injury using temporal interference stimulation
Authors: Sunshine Michael D. , Cassarà Antonino M. , Neufeld Esra , Grossman Nir , Mareci Thomas H. , Otto Kevin J. , Boyden Edward S. , Fuller David D.
Published: January 2021

Respiratory insufficiency is a leading cause of death due to drug overdose or neuromuscular disease. We hypothesized that a stimulation paradigm using temporal interference (TI) could restore breathing in such conditions. Following opioid overdose in rats, two high frequency (5000 Hz and 5001 Hz), low amplitude waveforms delivered via intramuscular wires in the neck immediately activated the diaphragm and restored ventilation in phase with waveform offset (1 Hz or 60 breaths/min). Following cervical spinal cord injury (SCI), TI stimulation via dorsally placed epidural electrodes uni- or bilaterally activated the diaphragm depending on current and electrode position. In silico modeling indicated that an interferential signal in the ventral spinal cord predicted the evoked response (left versus right diaphragm) and current-ratio-based steering. We conclude that TI stimulation can activate spinal motor neurons after SCI and prevent fatal apnea during drug overdose by restoring ventilation with minimally invasive electrodes.
Chondroitin 6-sulfate represses keratinocyte proliferation in mouse skin, which is associated with psoriasis
Authors: Kitazawa Kazuyuki , Nadanaka Satomi , Kadomatsu Kenji , Kitagawa Hiroshi
Published: January 2021

Chondroitin sulfates are implicated in epidermal biology, but functional significance of chondroitin sulfates remains unclear. Here, we report that chondroitin 6-sulfate is important for the maintenance of epidermal homeostasis. Mice deficient in chondroitin 6-O-sulfotransferase-1 (C6st-1), which is involved in biosynthesis of chondroitin 6-sulfate, exhibited keratinocyte hyperproliferation and impaired skin permeability barrier function. Chondroitin 6-sulfate directly interacted with the EGF receptor and negatively controlled ligand-induced EGF receptor signaling. Normal function of hyperproliferative C6st-1-knockout mouse-derived keratinocytes was rescued by treatment with exogenous chondroitin 6-sulfate. Epidermal hyperplasia, induced using imiquimod, was more severe in C6st-1-knockout mice than in C6st-1 wild-type mice. Taken together, these findings indicate that chondroitin 6-sulfate represses keratinocyte proliferation in normal skin, and that the expression level of C6st-1 may be associated with susceptibility to psoriasis.
Porphyromonas gingivalis fimbrial protein Mfa5 contains a von Willebrand factor domain and an intramolecular isopeptide
Authors: Heidler Thomas V. , Ernits Karin , Ziolkowska Agnieszka , Claesson Rolf , Persson Karina
Published: January 2021

The Gram-negative bacterium Porphyromonas gingivalis is a secondary colonizer of the oral biofilm and is involved in the onset and progression of periodontitis. Its fimbriae, of type-V, are important for attachment to other microorganisms in the biofilm and for adhesion to host cells. The fimbriae are assembled from five proteins encoded by the mfa1 operon, of which Mfa5 is one of the ancillary tip proteins. Here we report the X-ray structure of the N-terminal half of Mfa5, which reveals a von Willebrand factor domain and two IgG-like domains. One of the IgG-like domains is stabilized by an intramolecular isopeptide bond, which is the first such bond observed in a Gram-negative bacterium. These features make Mfa5 structurally more related to streptococcal adhesins than to the other P. gingivalis Mfa proteins. The structure reported here indicates that horizontal gene transfer has occurred among the bacteria within the oral biofilm.
Design and optimisation of dendrimer-conjugated Bcl-2/xL inhibitor, AZD0466, with improved therapeutic index for cancer therapy
Authors: Patterson Claire M. , Balachander Srividya B. , Grant Iain , Pop-Damkov Petar , Kelly Brian , McCoull William , Parker Jeremy , Giannis Michael , Hill Kathryn J. , Gibbons Francis D. , Hennessy Edward J. , Kemmitt Paul , Harmer Alexander R. , Gales Sonya , Purbrick Stuart , Redmond Sean , Skinner Matthew , Graham Lorraine , Secrist J. Paul , Schuller Alwin G. , Wen Shenghua , Adam Ammar , Reimer Corinne , Cidado Justin , Wild Martin , Gangl Eric , Fawell Stephen E. , Saeh Jamal , Davies Barry R. , Owen David J. , Ashford Marianne B.
Published: January 2021

Dual Bcl-2/Bcl-xL inhibitors are expected to deliver therapeutic benefit in many haematological and solid malignancies, however, their use is limited by tolerability issues. AZD4320, a potent dual Bcl-2/Bcl-xL inhibitor, has shown good efficacy however had dose limiting cardiovascular toxicity in preclinical species, coupled with challenging physicochemical properties, which prevented its clinical development. Here, we describe the design and development of AZD0466, a drug-dendrimer conjugate, where AZD4320 is chemically conjugated to a PEGylated poly-lysine dendrimer. Mathematical modelling was employed to determine the optimal release rate of the drug from the dendrimer for maximal therapeutic index in terms of preclinical anti-tumour efficacy and cardiovascular tolerability. The optimised candidate is shown to be efficacious and better tolerated in preclinical models compared with AZD4320 alone. The AZD4320-dendrimer conjugate (AZD0466) identified, through mathematical modelling, has resulted in an improved therapeutic index and thus enabled progression of this promising dual Bcl-2/Bcl-xL inhibitor into clinical development.
PRMT3 interacts with ALDH1A1 and regulates gene-expression by inhibiting retinoic acid signaling
Authors: Verma Mamta , Khan Mohd. Imran K. , Kadumuri Rajashekar Varma , Chakrapani Baskar , Awasthi Sharad , Mahesh Arun , Govindaraju Gayathri , Chavali Pavithra L , Rajavelu Arumugam , Chavali Sreenivas , Dhayalan Arunkumar
Published: January 2021

Protein arginine methyltransferase 3 (PRMT3) regulates protein functions by introducing asymmetric dimethylation marks at the arginine residues in proteins. However, very little is known about the interaction partners of PRMT3 and their functional outcomes. Using yeast-two hybrid screening, we identified Retinal dehydrogenase 1 (ALDH1A1) as a potential interaction partner of PRMT3 and confirmed this interaction using different methods. ALDH1A1 regulates variety of cellular processes by catalyzing the conversion of retinaldehyde to retinoic acid. By molecular docking and site-directed mutagenesis, we identified the specific residues in the catalytic domain of PRMT3 that facilitate interaction with the C-terminal region of ALDH1A1. PRMT3 inhibits the enzymatic activity of ALDH1A1 and negatively regulates the expression of retinoic acid responsive genes in a methyltransferase activity independent manner. Our findings show that in addition to regulating protein functions by introducing methylation modifications, PRMT3 could also regulate global gene expression through protein-protein interactions.
Experimental and theoretical evidence for oriented aggregate crystal growth of CoO in a polyol
Authors: Gaudisson Thomas , Sharma Surender K. , Mohamed Rahamane , Sitamtze Youmbi B. , Menguy Nicolas , Calvayrac Florent , Seydou Mahamadou , Ammar-Merah Souad
Published: January 2021

CoO submicrometer-sized pseudo-single crystals were produced in polyol thanks to an oriented aggregation crystal growth driven by the polyol molecules themselves.
Properties of the tert-butyl halide solvolysis transition states
Authors: Abraham Michael H. , Martins Filomena , Elvas-Leitão Ruben , Moreira Luís
Published: January 2021

The rate of solvolysis of tert-butyl halides is increased by both nucleophilic and electrophilic solvents.
Theoretical study of hydrogen bonding interactions in substituted nitroxide radicals
Authors: Ismail Thufail M. , Mohan Neetha , Sajith P. K.
Published: January 2021

Interaction energy (Eint) of hydrogen bonded complexes of nitroxide radicals can be assessed in terms of the deepest minimum of molecular electrostatic potential (Vmin).
Rapid membrane-specific AIEgen featuring with wash-free imaging and sensitive light-excited killing of cells, bacteria, and fungi
Authors: Zhang Kexin , Hu Rong , Wang Zhiming , Tang Ben Zhong
Published: January 2021

C6-BD equipped with AIE and ESIPT characteristics was used to visualize the cell membrane with high selectivity, stability, and wash-free operation. It also universal for imaging of bacteria and fungi with light-excited killing via ROS generation.
Hydrophobic nano SiO2 as flow-enhancing additives and flame retardant synergizes with CaCO3 to suppress gas explosion
Authors: Xie Jibiao , Zhang Jiaqi , Ding Ce , Wang Xiaoli
Published: January 2021

The suppression effect of hydrophobic nano SiO2 of different concentrations as flow-enhancing additives synergizing with CaCO3 to inhibit gas explosions was systematically studied in a self-built LabVIEW-based explosion test platform.
Superior anti-infective potential of eugenol–casein nanoparticles combined with polyethylene glycol against Colletotrichum musae infections
Authors: Hao Xueyan , Han Shuya , Qin Dingkui , Zhang Yahui , Jin Peng , Du Qizhen
Published: January 2021

The aim of this study was to improve the stability of eugenol–casein nanoparticles (EL–CS-NPs) through polyethylene glycol (PEG) modification.
Solvent-assisted strongly enhanced light-emitting electrochemiluminescent devices for lighting applications
Authors: Kim Joo Yeon , Cheon Sanghoon , Kim Dae Kyom , Nam Sooji , Han Jisu , Hwang Chi-Sun , Piao Yuanzhe , Lee Jeong-Ik
Published: January 2021

Simple and easily preparable electrochemiluminescent device (ECLD) is a promising alternative to LED and/or OLED for lighting application.
Simulation of bi-layer cathode materials with experimentally validated parameters to improve ion diffusion and discharge capacity
Authors: Chowdhury Ridwanur , Banerjee Aayan , Zhao Yan , Liu Xinhua , Brandon Nigel
Published: January 2021

Simulation shows that higher electrode utilization (next to current collector) and first discharge capacity can be achieved at high C-rates with bi-layer design compare to conventional electrodes, alongside an increase in energy-power density.
Non-precious cobalt phthalocyanine-embedded iron ore electrocatalysts for hydrogen evolution reactions
Authors: CP Keshavananda Prabhu , Aralekallu Shambhulinga , Sajjan Veeresh A. , Palanna Manjunatha , Kumar Sharath , Sannegowda Lokesh Koodlur
Published: January 2021

Efficient water splitting reactions lead to sustainable hydrogen production, which is the fuel for fuel cell devices for clean energy production.
Metal–organic framework (MOF)-derived amorphous nickel boride: an electroactive material for electrochemical energy conversion and storage application
Authors: Tripathy Rajat K. , Samantara Aneeya K. , Behera J. N.
Published: January 2021

A single step redox approach that transformed the crystalline Ni-MOF to amorphous nickel boride (NiB) nanostructures showed excellent electrocatalytic (oxygen evolution reaction; OER) and charge storage (supercapacitor) performances.
DFC: Device‐free human counting through WiFi fine‐grained subcarrier information
Authors: Jeong Jaehoon (Paul) , Shen Yiwen , Kim Seokhwa , Choe Daegeun , Lee Keuntae , Kim Yongserk
Published: January 2021

A device‐free human counting (DFC) algorithm that uses fine‐grained subcarrier information from WiFi devices, called channel state information (CSI), to count the number of people in indoor environments is proposed. The DFC algorithm extracts the features of average attenuation and variation of CSI amplitudes caused by human motions, and puts the features into a training process to improve the counting accuracy. Through a bootstrapping process, the DFC can estimate the number of people standing in the middle of a WiFi link by constructing a probability model with the CSI signals at a receiver side. With this human counting capability, the DFC can support the efficient monitoring and automatic control of electrical devices (e.g. air conditioner, heater, bulb, and beam projector) indoors. Through a real implementation and experiments, it is shown that the DFC algorithm outperforms the state‐of‐the‐art DFC algorithm based on RSSI in indoor environments with human mobility. For a dynamic‐target case in a meeting room, for example, DFC can predict the number of people in an indoor space with an accuracy about 98% at best.
Image denoising based on BCOLTA: Dataset and study
Authors: Han Lili , Li Shujuan , Liu Xiuping
Published: January 2021

Robot deburring is an effective method for improving the surface quality of the high‐voltage copper contact. The first step of robot deburring is to acquire the burr images. We propose a new burr mathematical model and build a real burr image dataset for burr image denoising. In order to improve burr image denoising effects of the high‐voltage copper contact, this study proposes an online burr image denoising algorithm, that is, block cosparsity overcomplete learning transform algorithm (BCOLTA). The penalty term and the condition number are affected by the burr parameter. The clustering and transform alternate minimisation algorithms are adopted to achieve lower computational cost and better denoising effect. In addition, BCOLTA also has a good adaptibility to inherent noise images, especially in Gaussian noise. Compared with other traditional and deep learning algorithms by no reference and full reference image quality assessment methods, BCOLTA has state‐of‐the‐art denoising effects and computational complexity on dealing with burr images. This research will play an important role in the intelligent manufacturing field.
An assessment of a unmanned aerial vehicle‐based broadcast scenario assuming random terrestrial user locations
Authors: Vaiopoulos Nicholas , Vavoulas Alexander , Sandalidis Harilaos G.
Published: January 2021

With the advent of the new decade, unmanned aerial vehicles (UAVs) will increasingly play an active role mainly as broadband transmission relays for broadcast applications. In the present study, we consider a feasible network where a transmitter, mounted on a hill, is connected through an optical wireless link with a UAV, hovering at a certain height above the earth. The UAV provides coverage over a circular geographic area and communicates through a radio frequency (RF) link with a ground user who is randomly located inside the circular region. In this context, a mixed optical/RF link is established where the performance is thoroughly investigated in terms of the outage probability. We assume that the optical wireless link is affected by a plethora of deteriorating factors, including the presence of fog, or the atmospheric scintillation, while the RF link is subject to small‐scale fading. Depending on the appearance of fog or turbulence, two different problems occur with a different mathematical formulation. For both cases, we extract closed‐form expressions for the signal‐to‐noise ratio statistics, which are the critical component towards determining the outage probability. Then, the impact of the impairments for some typical parameter values is properly depicted in appropriate graphs.
Semiconductor racetrack resonator coupled to an S‐bent waveguide: Influence of the coupling coefficients on the unidirectional operation
Authors: Giannuzzi Giuseppe , Bardella Paolo
Published: January 2021

Semiconductor ring lasers have attracted remarkable interest as laser sources in photonic integrated circuits. They result in bidirectional laser owing to the rotation symmetry between the two counter‐propagating modes of the ring cavity. This symmetry can be broken embedding an S‐bend waveguide in the racetrack resonator, which generates an unbalanced loss mechanism and a non‐reciprocal gain between clockwise and counter‐clockwise direction beams. The propagating field along the resonator in the undesirable direction is evanescently coupled to the S element in correspondence of two coupling regions and converted into the preferred one. The authors examined how the field coupling coefficients of the couplers impact the resonator unidirectionality. In numerical simulations, the authors changed the coupler gap distance and the coupler length of the directional couplers to scan the full range of variability of the coefficients. The simulated performances of the resonator are discussed in terms of the extinction ratio between the clockwise and the counter‐clockwise modes as well as the power truly circulated in the two directions of the resonator net of all losses. The finite‐difference time‐domain method within Synopsys RSoft© suite was used to simulate the evolution of the counter‐propagating field along the racetrack.
Passive MIMO radar detection in the presence of clutter or multi‐path without reference channel
Authors: Fazlollahpoor Mohammad , Derakhtian Mostafa , Khorshidi Shapour
Published: January 2021

Target detection problem in a multiple‐input multiple‐output (MIMO) radar which includes non‐cooperative illuminators of opportunity (IOs) and spatially distributed receivers is discussed. The receivers utilize only one processing channel and discard the difficulties in providing an ideal version of the transmitted waveforms. The signal model, in addition to the receiver noise and the possible echo from the target of interest, considers the direct‐path and clutter/multi‐path interferences (DPI and MPI). A Rao test and an approximated GLR test detectors are proposed to solve the problem and an innovative recursive algorithm is proposed to simultaneously estimate the nuisance parameters in the test. Then, by regarding some matrix properties in the proposed Rao detector expression, a low complexity version of the Rao detector is proposed. Besides, two detectors based on Rao and GLR principles in the case of active MIMO radar are introduced as the performance upper‐bounds for the proposed detectors. The convergence and suitable performance of the proposed detectors are verified by numerical simulations.
Coherent compensation and high‐resolution technology of multi‐band inverse synthetic aperture radar fusion imaging
Authors: Zhu Xiaoxiu , Liu Limin , Guo Baofeng , Hu Wenhua , Ma Juntao , Shi Lin
Published: January 2021

Multi‐band inverse synthetic aperture radar (ISAR) fusion imaging technology can effectively improve the range resolution without incurring high hardware cost. The coherent phase between sub‐bands is a prerequisite to achieve multi‐band ISAR fusion imaging. Here, a joint approach of coherent compensation and high‐resolution imaging is proposed to compensate the incoherent phase and obtain high‐resolution ISAR fusion images. First, an incoherent phase estimation model based on sparse representation is established, and the phase estimation accuracy is improved by a modified coherent dictionary in case of off‐grid. Then, a multi‐band ISAR fusion imaging model based on sparse representation is established. The complex Gaussian scale mixture priors and the complex Gaussian priors are imposed on the scatterers and noise, respectively. The solution is derived in the complex domain based on the variational Bayesian expectation maximization framework. The proposed method can not only achieve better incoherent phase compensation in the case of off‐grid, but also obtain high‐quality ISAR fusion images under low signal‐to‐noise ratio and low bandwidth sampling ratio. Experimental results verify the effectiveness and robustness of the proposed method based on both numerical simulations and real data.
A giant X-ray dust scattering ring discovered with SRG/eROSITA around the black hole transient MAXI J1348–630
Authors: Lamer G. , Schwope A. D. , Predehl P. , Traulsen I. , Wilms J. , Freyberg M.
Published: January 2021

We report the discovery of a giant dust scattering ring around the Black Hole transient MAXI J1348−630 with SRG/eROSITA during its first X-ray all-sky survey. During the discovery observation in February 2020, the ring had an outer diameter of 1.3 deg, growing to 1.6 deg by the time of the second all-sky survey scan in August 2020. This makes the new dust ring by far the largest X-ray scattering ring observed so far. Dust scattering halos, in particular the rings found around transient sources, provide an opportunity to make precise distance measurements towards the original X-ray sources. We combine data from SRG/eROSITA, XMM-Newton, MAXI, and Gaia to measure the geometrical distance of MAXI J1348−630. The Gaia data place the scattering dust at a distance of 2050 pc. Based on the measured time lags and the geometry of the ring we find MAXI J1348−630 at a distance of 3390 pc with a statistical uncertainty of only 1.1% and a systematic uncertainty of 10% caused mainly by the parallax offset of Gaia. This result makes MAXI J1348−630 one of the black hole transients with the most accurately determined distances. The new distance leads to a revised mass estimate for the black hole of 11 ± 2 M⊙. The transition to the soft state during the outburst occurred when the bolometric luminosity of MAXI J1348−630 reached 1.7% of its Eddington luminosity.
APOGEE DR16: A multi-zone chemical evolution model for the Galactic disc based on MCMC methods
Authors: Spitoni E. , Verma K. , Silva Aguirre V. , Vincenzo F. , Matteucci F. , Vaičekauskaitė B. , Palla M. , Grisoni V. , Calura F.
Published: January 2021

Context.The analysis of the latest release of the Apache Point Observatory Galactic Evolution Experiment project (APOGEE DR16) data suggests the existence of a clear distinction between two sequences of disc stars at different Galactocentric distances in the [α/Fe] versus [Fe/H] abundance ratio space: the so-called high-αsequence, classically associated with an old population of stars in the thick disc with high average [α/Fe], and the low-αsequence, which mostly comprises relatively young stars in the thin disc with low average [α/Fe].

Aims.We aim to constrain a multi-zone two-infall chemical evolution model designed for regions at different Galactocentric distances using measured chemical abundances from the APOGEE DR16 sample.

Methods.We performed a Bayesian analysis based on a Markov chain Monte Carlo method to fit our multi-zone two-infall chemical evolution model to the APOGEE DR16 data.

Results.An inside-out formation of the Galaxy disc naturally emerges from the best fit of our two-infall chemical-evolution model to APOGEE-DR16: Inner Galactic regions are assembled on shorter timescales compared to the external ones. In the outer disc (with radiiR > 6 kpc), the chemical dilution due to a late accretion event of gas with a primordial chemical composition is the main driver of the [Mg/Fe] versus [Fe/H] abundance pattern in the low-αsequence. In the inner disc, in the framework of the two-infall model, we confirm the presence of an enriched gas infall in the low-αphase as suggested by chemo-dynamical models. Our Bayesian analysis of the recent APOGEE DR16 data suggests a significant delay time, ranging from ∼3.0 to 4.7 Gyr, between the first and second gas infall events for all the analysed Galactocentric regions. The best fit model reproduces several observational constraints such as: (i) the present-day stellar and gas surface density profiles; (ii) the present-day abundance gradients; (iii) the star formation rate profile; and (iv) the solar abundance values.

Conclusions.Our results propose a clear interpretation of the [Mg/Fe] versus [Fe/H] relations along the Galactic discs. The signatures of a delayed gas-rich merger which gives rise to a hiatus in the star formation history of the Galaxy are impressed in the [Mg/Fe] versus [Fe/H] relation, determining how the low-αstars are distributed in the abundance space at different Galactocentric distances, which is in agreement with the finding of recent chemo-dynamical simulations.
Spectroscopy and polarimetry of the gravitationally lensed quasar Q0957+561
Authors: Popović L. Č. , Afanasiev V. L. , Shablovinskaya E. S. , Ardilanov V. I. , Savić Dj.
Published: January 2021

Context. We present new spectroscopic and polarimetric observations of the first discovered gravitational lens, Q0957+561. The lensed quasar has been observed with the 6 m telescope of the Special Astrophysical Observatory (Russia) in polarimetric and spectroscopic modes.

Aims. We explore the spectropolarimetric parameters of the A and B components of Q0957+561 to investigate the innermost structure of gravitationally lensed quasars and explore the nature of polarization in lensed quasars. Additionally, we aim to compare their present-day spectral characteristics with previous observations in order to study long-term spectral changes.

Methods. We perform new spectral and polarization observations of the Q0957+561 A and B images. After observed data reduction, we analyse the spectral characteristics of the lensed quasar, comparing the spectra of the A and B images, as well as comparing previously observed image spectra with present-day ones. The polarization parameters of the two images are also compared. Furthermore, we model the macro-lens influence on the polarization of the images, representing the gravitational lens with a singular isothermal elliptical potential.

Results. We find that the brightness and the spectral energy distribution ratio of components A and B have changed over a long period. Polarization in the broad lines of components A and B show that equatorial scattering cannot be detected in this lensed quasar. We find wavelength-dependent polarization that may be explained as a combination of the polarization from the disc and the outflowing material. There is a significant difference between the polarization parameters of the A and B images: The B component shows a higher polarization rate and polarization angle. However, both polarization vectors are nearly perpendicular to the observed radio jet projection. This indicates that the polarization in the continuum comes from the accretion disc. Our simple lensing model of a polarized source shows that, in principle, macro lenses can cause the observed differences in the polarization parameters of the Q0957+561A and B images. Using the Mg II broad line and luminosity of component A, we estimate the Q0957+561 black hole mass to be MSMBH ≈ (4.8 − 6.1) × 108 M⊙.
Kato smoothing properties of a class of nonlinear dispersive wave equations on a periodic domain
Authors: Sun Shu-Ming , Yang Xin , Zhang Bing-Yu , Zhong Ning
Published: January 2021

The solutions of the Cauchy problem of the KdV equation on a periodic domain 𝕋,

[see formula in PDF]

possess neither the sharp Kato smoothing property,

[see formula in PDF]

nor the Kato smoothing property,

[see formula in PDF]

Considered in this article is the Cauchy problem of the following dispersive equations posed on the periodic domain 𝕋, (See Eq. (1) below)

[see formula in PDF]

where g ∈ C∞(𝕋) is a real value function with the support

[see formula in PDF]

It is shown that

(1) if ω ≠ ∅, then the solutions of the Cauchy problem (1) possess the Kato smoothing property;

(2) if g is a nonzero constant function, then the solutions of the Cauchy problem (1) possess the sharp Kato smoothing property.
The Efficiency of Discrete Event Systems for the General Pickup and Delivery Problem with Electric Vehicles
Authors: Outalha Abdelhak , Lakhal Yassine , Baghli Fatima Zahra , Kzaiber Fouzia
Published: January 2021

Transport on-demand is an issue in the Vehicle Routing Problem which involves transporting a collection of goods from the source (depot) to their destination (customers) and inversely. This paper analyzes and forecasts the viability of using discrete event systems in a subset of this general problem known as pickup and delivery problems in the literature and projects on an automated manufacturing cell with an optimization approach for the vehicle’s energy consumption.
Thermal conductivity of clay based material incorporating Argan Shell: Experimental characterization
Authors: Idoum Aicha , Bammou Lahcen , Tiskatine Rachid , Aharoune Ahmed
Published: January 2021

This research investigated the impact of agricultural biomass additives (Argan shell) on the thermal and physical properties of fired clay bricks for building application. The objective of the study is to characterize the selected materials from molecule up to the final materials used in buildings. The materials used in this study, are soil and Argan shells, locally available materials for brick making. The Argan shells were grinded and then added to the clay mixture. The Clay brick shows a formation of pores during the firing process up to 1050°C. As results, the bulk density of the clay bricks decreased due to the pores formation. On the other hand, the thermal conductivity of the clay bricks was reduced by 53% using 20wt% of the biomass additives.
Numerical Simulation of the Impact ofIce Accumulation on a Composite Wind Turbine Blades located in a Cold Climate
Authors: Lagdani O. , Tarfaoui M. , Nachtane M. , Trihi M. , Laaouidi H.
Published: January 2021

The blades of wind turbines placed in cold climate regions are exposed to the risk of icing phenomena which impact their lifetimes. This paper proposes a numerical model to simulate 50 mm ice thickness localized on the tip side of a horizontal wind turbine blade, and to study its mechanical behavior. The wind turbine blade wasmodeled with the finite element method (FEM)in ABAQUS software taking into account aerodynamic, centrifugal and inertial loads under the conditions of service of the blade.Numerical tests haveevaluated the behavior of different composite materials and compared with each other. Damage mode based on the Hashin criteria was defined. Carbon fibers were considered to be the most rigid material which results in thinner, stiffer and lighter blades.
Numerical Characterization of Behavior Under Uniaxial Tension and Modelling of Bending of Mechanical Behavior of Polymeric Materials (HIPS) And Comparison with Experience
Authors: Baha Meryem , Lamarti Amal , Sehaqui Rachid , Hachim Abdelilah , Ouhimmou Siham
Published: January 2021

Considering the wide use of high impact polystyrene in different fields, it is important to know its behavior in different environmental conditions. This work is interested in the characterization of the behavior of high impact polystyrene (HIPS) under tensile and bending stress.
Virtual power plant: state of the art providing energy flexibility to local distribution grids
Authors: Ullah Zahid , Hussain Mirjat Nayyar
Published: January 2021

Integrating decentralised energy sources into the traditional distribution networks can result in technical issues impacting the power quality. Innovative ideas are, therefore, needed to promote the transformation of systems to a smart grid. Distribution System operator (DSO) could make use of the flexibility of emerging technologies as a method to address these power quality issues. This study aims to present an overview of a local flexibility market (LFM) which will allow DSO requirements to be fulfilled through the (VPP) as an energy flexibility provider. The required optimization loads, generators and as well as storage units, are undertaken in the general algebraic modeling simulation (GAMS) environment. The aim of the optimization problem is to provide DSOs the opportunity to increase or curtail the local generations and loads in order to satisfy their requirement. The VPP will then be responsible for handling the relevant requests in real time to ensure the correct operating schedule of a resource is applied. The preliminary results of simulation studies presented in this paper have shown that the local market framework for flexibility could have potential for deferring investments in distribution network capacity, minimizing energy costs and improving the hosting capacity of distribution networks.