bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparative assessment of the prevalence, practices and factors associated with self‐medication with antibiotics in Africa
Authors: Yeika Eugene Vernyuy , Ingelbeen Brecht , Kemah Ben‐Lawrence , Wirsiy Frankline Sevidzem , Fomengia Joseph Nkeangu , van der Sande Marianne A. B.
Published: May 2021

Objective

To evaluate and compare the prevalence, reasons, sources and factors associated with self‐medication with antibiotics (SMA) within Africa.

Methods

Systematic review and meta‐analysis. An electronic search of PubMed and Google Scholar databases was performed for observational studies conducted between January 2005 and February 2020. Two reviewers independently screened abstracts and full texts using the PRISMA flowchart and performed quality assessment of eligible studies. Both qualitative and quantitative syntheses were carried out.

Results

Forty studies from 19 countries were eligible for qualitative synthesis. The prevalence of SMA in Africa ranged from 12.1% to 93.9% with a median prevalence of 55.7% (IQR 41–75%). Western Africa was the sub‐region with the highest reported prevalence of 70.1% (IQR 48.3–82.1%), followed by Northern Africa with 48.1% (IQR 41.1–64.3%). We identified 27 antibiotics used for self‐medication from 13 different antibiotic classes. Most frequently used antibiotics were penicillins (31 studies), tetracyclines (25 studies) and fluoroquinolones (23 studies). 41% of these antibiotics belong to the WHO Watch Group. The most frequent indications for SMA were upper respiratory tract infections (27 studies), gastrointestinal tract symptoms (25 studies) and febrile illnesses (18 studies). Common sources of antibiotics used for self‐medication were community pharmacies (31 studies), family/friends (20 studies), leftover antibiotics (19 studies) and patent medicine stores (18 studies). The most frequently reported factor associated with SMA was no education/low educational status (nine studies).

Conclusions

The prevalence of SMA is high in Africa and varies across sub‐regions with the highest prevalence reported in Western Africa. Drivers of SMA are complex, comprising of socio‐economic factors and insufficient access to health care coupled with poorly implemented policies regulating antibiotic sales.
Effect of contrasting maternal nitrogen environments on Buglossoides arvensis seed germination response to gibberellic and abscisic acids
Authors: Longás María de las Mercedes , Sabbatini Mario Ricardo , Batlla Diego , Chantre Guillermo Rubén
Published: May 2021

Nitrogen availability in Buglossoides arvensis mother plants influences seed dormancy level. Abscisic acid (ABA) levels chiefly determine primary dormancy during embryo maturation and its maintenance depends on ABA/gibberellic acid (GA) balance. We hypothesised that soil nitrogen fertilisation of B. arvensis mother plants affects seed sensitivity to hormonal germination promotors and inhibitors. The purpose of the present work was therefore to investigate to what extent the changes that occur in seed germinability as a result of maternal nitrogen fertilisation (with ‐N(+)‐ and without ‐N(−)‐) are paralleled by changes in ABA or GAs de novo synthesis and embryonic sensitivity to ABA or GAs. Seed germinability was assessed under a gradient of ABA and GA3 and their corresponding de novo synthesis inhibitors (fluridone ‐FLU‐ and paclobutrazol ‐PBZ‐). B. arvensis seeds were incubated at suboptimal (7°C), optimal (15°C) and supraoptimal (20°C) temperatures. Results indicated a higher germination of N(+) seeds, irrespective of hormone type, dose or incubation temperature. N(−) seeds were more sensitive to FLU at 7°C and to GA3 at 15°C, whereas N(+) seeds were more sensitive to FLU at 15‐20°C and to PBZ at 7°C. At 20°C, N(+) seed germinability was stimulated by GA3 counteracting the thermo‐inhibitory effect. The higher seed germinability recorded from nitrogen‐fertilised plants could be associated to a decrease in seed dormancy levels due to lower ABA levels during embryogenesis, thus requiring a lower amount of GAs to germinate. Further studies are required to confirm this hypothesis.
On -local
Authors: Mathew Akhil
Published: May 2021

We discuss some general properties of $\mathrm {TR}$ and its $K(1)$-localization. We prove that after $K(1)$-localization, $\mathrm {TR}$ of $H\mathbb {Z}$-algebras is a truncating invariant in the Land–Tamme sense, and deduce $h$-descent results. We show that for regular rings in mixed characteristic, $\mathrm {TR}$ is asymptotically $K(1)$-local, extending results of Hesselholt and Madsen. As an application of these methods and recent advances in the theory of cyclotomic spectra, we construct an analog of Thomason's spectral sequence relating $K(1)$-local $K$-theory and étale cohomology for $K(1)$-local $\mathrm {TR}$.
Singularity Loci, Bifurcated Evolution Routes, and Configuration Transitions of Reconfigurable Legged Mobile Lander From Adjusting, Landing, to Roving
Authors: Han Youcheng , Zhou Caizhi , Guo Weizhong
Published: May 2021

This paper presents the reconfigurable legged mobile lander (ReLML) with its modes from adjusting, landing, to roving. Based on the invented metamorphic variable-axis revolute hinge, the actuated link has three alternative phases of rotating around either of two orthogonal topological axes or locking itself to the base as a rigid body. This property enables the ReLML to switch among three modes and within two driving states (as the adjusting and roving modes are active mechanisms driven by motors, while the landing truss is regarded as a passive mechanism driven by the touchdown impact force exerted on footpad). The unified differential kinematics for the ReLML is established by the screw-based Jacobian modeling, unifying both active and passive operation phases throughout all modes. Afterward, the distributions of workspaces and singularity loci in three modes are discussed for the multi-solution sake, and the selection principle of the practicable solution pattern is proposed to obtain the actual workspace, singularity loci, and configurations. The results stemming from the Jacobian-matrix-based method and the Grassmann-geometry-based method give mutual authentication. Finally, as prospects for promising applications, four bifurcated evolution routes and configuration transitions are figured out and compared.
Heat Transfer Characteristics Analysis on a Fully Cooled Vane With Varied Density Ratios
Authors: Yao Chun-yi , Zhang Zheng , Zhang Bo-lun , Zhu Hui-ren , Liu Cun-liang
Published: May 2021

The objective of this experimental investigation was to determine the cooling performance of a fully cooled vane with 18 rows of cylinder cooling holes. The exit Reynolds number in the wind tunnel normalized by the true chord was 500,000 with an inlet turbulence intensity of 15%. The film cooling effectiveness and heat transfer coefficient distribution were obtained by the transient liquid crystal (TLC) technology, three mass flow ratios (MFRs = 7.0%, 9.9%, 11%) and two density ratios (DRs = 1.0, 1.5) were tested. The results show that the film cooling effectiveness distribution on the suction side is more uniform and the coolant injection trajectory is much longer than that on the pressure side. As the density ratio increasing to 1.5, the more laterally uniform film cooling effectiveness contour on the pressure side is observed and the spatially averaged film cooling effectiveness is increased by 11–43%. For the MFR = 7.0%, the coolant injection with low momentum thickens the boundary layer and reduces the heat transfer coefficient in the mid-chord region of the pressure side. Both the increased mass flow ratio and decreased density ratio result in a higher heat transfer coefficient, while do not alter the distribution trend. By calculating the heat flux ratio, the reduction in the heat flux at DR = 1.5 is found to be within 20% in most areas than that of DR = 1.0 on the vane surface.
Analysis and modeling of dialect information in Ao, a low resource language
Authors: Tzudir Moakala , Sarmah Priyankoo , Prasanna S. R. Mahadeva
Published: May 2021

Ao is a Tibeto-Burman language spoken in Nagaland, India. It is a low resource, tonal language with three lexical tones, namely, high, mid, and low. However, tone assignment on lexical words may differ among the three dialects of Ao, namely, Chungli, Mongsen, and Changki. In this work, an acoustic study is conducted on the three tones in the three dialects of Ao. It was found that the acoustic characteristics of the tones in the Changki dialect are markedly different from that of the Chungli and the Mongsen dialects. Hence, in the latter part of the work, automatic dialect identification (DID) in the Ao dialects is attempted with Mel Frequency Cepstral Coefficients, Shifted Delta Cepstral coefficients, and F0 features using the Gaussian Mixture models. It is confirmed that in both text-dependent and text-independent DID, the F0 features improve the accuracy of classification.
Horizontal Gene Transfer of Genes Encoding Copper-Containing Membrane-Bound Monooxygenase (CuMMO) and Soluble Di-iron Monooxygenase (SDIMO) in Ethane- and Propane-Oxidizing
Rhodococcus
Bacteria
Authors: Zou Bin , Huang Ying , Zhang Pan-Pan , Ding Xiao-Ming , Op den Camp Huub J. M. , Quan Zhe-Xue
Published: May 2021

CuMMOs and SDIMOs initiate the aerobic oxidation of alkanes in bacteria. Here, the supposition that horizontally transferred plasmid-based CuMMO and SDIMO genes confer on the recipient a similar ability to use ethane and propane was proposed and confirmed in
Rhodococcus.
This study is a living example of HGT of CuMMOs and SDIMOs and outlines the plasmid-borne properties responsible for gaseous alkane degradation.
Application of Four Genotyping Methods to Mycoplasma bovis Isolates Derived from Western Canadian Feedlot Cattle
Authors: Kinnear Andrea , Waldner Matthew , McAllister Tim A. , Zaheer Rahat , Register Karen , Jelinski Murray
Published: May 2021

Mycoplasma bovis
is a significant pathogen of feedlot cattle, responsible for chronic pneumonia and polyarthritis syndrome (CPPS).
M. bovis
isolates (
n 
= 129) were used to compare four methods of phylogenetic analysis and to determine if the isolates’ genotypes were associated with phenotypes. Metadata included the health status of the animal from which an isolate was derived (healthy, diseased, or dead), anatomical location (nasopharynx, lung, or joint), feedlot, and production year (2006 to 2018).
Relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals: a rapid scoping review
Authors: McEvoy David , McAloon Conor , Collins Aine , Hunt Kevin , Butler Francis , Byrne Andrew , Casey-Bryars Miriam , Barber Ann , Griffin John , Lane Elizabeth Ann , Wall Patrick , More Simon John
Published: May 2021

Objectives

The aim of this study was to determine the relative infectiousness of asymptomatic SARS-CoV-2 infected persons compared with symptomatic individuals based on a scoping review of available literature.

Design

Rapid scoping review of peer-reviewed literature from 1 January to 5 December 2020 using the LitCovid database and the Cochrane library.

Setting

International studies on the infectiousness of individuals infected with SARS-CoV-2.

Participants

Studies were selected for inclusion if they defined asymptomatics as a separate cohort distinct from presymptomatics and if they provided a quantitative measure of the infectiousness of asymptomatics relative to symptomatics.

Primary outcome measures

PCR result (PCR studies), the rate of infection (mathematical modelling studies) and secondary attack rate (contact tracing studies) - in each case from asymptomatic in comparison with symptomatic individuals.

Results

There are only a limited number of published studies that report estimates of relative infectiousness of asymptomatic compared with symptomatic individuals. 12 studies were included after the screening process. Significant differences exist in the definition of infectiousness. PCR studies in general show no difference in shedding levels between symptomatic and asymptomatic individuals; however, the number of study subjects is generally limited. Two modelling studies estimate relative infectiousness to be 0.43 and 0.57, but both of these were more reflective of the infectiousness of undocumented rather than asymptomatic cases. The results from contact tracing studies include estimates of relative infectiousness of 0, but with insufficient evidence to conclude that it is significantly different from 1.

Conclusions

There is considerable heterogeneity in estimates of relative infectiousness highlighting the need for further investigation of this important parameter. It is not possible to provide any conclusive estimate of relative infectiousness, as the estimates from the reviewed studies varied between 0 and 1.
Safety and efficacy of transcarotid artery revascularisation versus carotid endarterectomy: protocol for a systematic review and meta-analysis study
Authors: Bai Xuesong , Zhang Xiao , Yang Wuyang , Wang Tao , Wang Yan , Feng Yao , Yang Kun , Wang Xue , Ma Yan , Jiao Liqun
Published: May 2021

Introduction

In recent years, the transcarotid artery revascularisation (TCAR) with flow reversal technique has been developed to treat carotid artery stenosis. The superiority of TCAR over transfemoral carotid artery stenting has been demonstrated. However, the safety and efficacy of TCAR and carotid endarterectomy remain unclear. This study aims to introduce a protocol for a systematic review and meta-analysis to compare the morbidity and mortality rates between TCAR and carotid endarterectomy in the treatment of atherosclerotic carotid artery stenosis.

Methods and analysis

This protocol was drafted using the Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols statement. Herein, major databases will be searched, including Medline, Web of Science, Embase and the Cochrane Library, and randomised controlled trials and high-quality observational studies will be included. We will screen all studies published from January 2000 to March 2021. Bias risk will be evaluated using the Cochrane Collaboration criteria or Methodological Index for Non-randomised Studies criteria, depending on the study type. Two reviewers will select eligible studies and extract the data independently. The primary outcome will include stroke or death during the perioperative period and follow-up. Subgroup and sensitivity analyses will be performed to explore any potential sources of heterogeneity. Specific results will be described in a narrative form when available eligible studies are insufficient for meta-analysis. Publication bias will be assessed using a funnel plot.

Ethics and dissemination

This study will summarise and analyse the existing literature; hence, ethics approval will not be required. The final results may be published at a relevant academic conference or in a journal.

PROSPERO registration number

CRD42020178691.
Trends and socioeconomic disparities in all-cause mortality among adults with diagnosed diabetes by race/ethnicity: a population-based cohort study - USA, 1997–2015
Authors: Mercado Carla , Beckles Gloria , Cheng Yiling , Bullard Kai McKeever , Saydah Sharon , Gregg Edward , Imperatore Giuseppina
Published: May 2021

Objectives

By race/ethnicity and socioeconomic position (SEP), to estimate and examine changes over time in (1) mortality rate, (2) mortality disparities and (3) excess mortality risk attributed to diagnosed diabetes (DM).

Design

Population-based cohort study using National Health Interview Survey data linked to mortality status from the National Death Index from survey year up to 31 December 2015 with 5 years person-time.

Participants

US adults aged ≥25 years with (31 586) and without (332 451) DM.

Primary outcome

Age-adjusted all-cause mortality rate for US adults with DM in each subgroup of SEP (education attainment and income-to-poverty ratio (IPR)) and time (1997–2001, 2002–2006 and 2007–2011).

Results

Among adults with DM, mortality rates fell from 23.5/1000 person-years (p-y) in 1997–2001 to 18.1/1000 p-y in 2007–2011 with changes of −5.2/1000 p-y for non-Hispanic whites; −5.2/1000 p-y for non-Hispanic blacks; and −5.4/1000 p-y for Hispanics. Rates significantly declined within SEP groups, measured as education attainment (high school=−4.8/1000 p-y) and IPR group (poor=−7.9/1000 p-y; middle income=−4.7/1000 p-y; and high income=−6.2/1000 p-y; but not for near poor). For adults with DM, statistically significant all-cause mortality disparity showed greater mortality rates for the lowest than the highest SEP level (education attainment and IPR) in each time period. However, patterns in mortality trends and disparity varied by race/ethnicity. The excess mortality risk attributed to DM significantly decreased from 1997–2001 to 2007–2011, within SEP levels, and among Hispanics and non-Hispanic whites; but no statistically significant changes among non-Hispanic blacks.

Conclusions

There were substantial improvements in all-cause mortality among US adults. However, we observed SEP disparities in mortality across race/ethnic groups or for adults with and without DM despite targeted efforts to improve access and quality of care among disproportionately affected populations.
Frontline interdisciplinary clinician perspectives on caring for patients with COVID-19: a qualitative study
Authors: Rao Hassan , Mancini Diana , Tong Allison , Khan Humaira , Santacruz Gutierrez Brissa , Mundo William , Collings Adriana , Cervantes Lilia
Published: May 2021

Objective

To describe the drivers of distress and motivations faced by interdisciplinary clinicians who were on the frontline caring for patients with COVID-19.

Design

50 semistructured interviews. Transcripts were analysed using qualitative thematic analysis.

Setting

A safety-net hospital in Denver, Colorado.

Participants

Interdisciplinary frontline clinicians including physicians, advance practice providers, nurses, respiratory therapists and paramedics providing inpatient hospital care to patients hospitalised for COVID-19.

Results

Fifty clinicians (32 women and 18 men) participated. Five themes with respective subthemes (in parentheses) were identified: depersonalisation and barriers to care (impeding rapport and compassion, focusing on infection risk at the expense of high-quality care, grief from witnessing patients suffer in isolation), powerless in uncertainty (inescapable awareness of personal risk, therapeutic doubt in a void of evidence, confronting ethical dilemmas, struggling with dynamic and unfamiliar challenges), overwhelmed and exhausted (burden of personal protective equipment (PPE), information overload and confusion, overstretched by additional responsibilities at work, compounded by personal life stressors, feeling vulnerable and dispensable, compassion fatigue, distress from the disproportionate impact on socially oppressed communities), bolstering morale and confidence (motivated by community and family support, equipped with data), and driven by moral duty (responsibility to patient care and community, collegial solidarity and collaboration, contributing to the greater good).

Conclusion

Frontline clinicians reported distress due to the challenges of PPE, uncertainty and powerlessness, new responsibilities at work and home, losing control of their schedules, grief from witnessing patients suffer in isolation and witnessing healthcare disparities exacerbated by this pandemic. Clinicians feel supported by their colleagues, families, and community and were driven by a sense of moral duty. Healthcare system should adopt strategies to minimise distress faced by interdisciplinary clinicians on the frontline of COVID-19.
Factors influencing thrombectomy decision making for primary medium vessel occlusion stroke
Authors: Cimflova Petra , Kappelhof Manon , Singh Nishita , Kashani Nima , Ospel Johanna Maria , McDonough Rosalie , Demchuk Andrew M , Menon Bijoy K , Sakai Nobuyuki , Chen Michael , Fiehler Jens , Goyal Mayank
Published: May 2021

Background

We aimed to explore the preference of stroke physicians to treat patients with primary medium vessel occlusion (MeVO) stroke with immediate endovascular treatment (EVT) in an international cross-sectional survey, as there is no clear guideline recommendation for EVT in these patients.

Methods

In the survey MeVO-Finding Rationales and Objectifying New Targets for IntervEntional Revascularization in Stroke (MeVO-FRONTIERS), participants were shown four cases of primary MeVOs (six scenarios per case) and asked whether they would treat those patients with EVT. Multivariable logistic regression with clustering by respondent was performed to assess factors influencing the decision to treat. Dominance analysis was performed to assess the influence of factors within the scenarios on decision making.

Results

Overall, 366 participants (56 women; 15%) from 44 countries provided 8784 answers to 24 scenarios. Most physicians (59.2%) would treat patients immediately with EVT. Younger patient age (incidence rate ratio (IRR) 1.24, 99% CI 1.19 to 1.30), higher National Institutes of Health Stroke Scale (NIHSS) score (IRR 1.69, 99% CI 1.57 to 1.82), and small core volume (IRR 1.35, 99% CI 1.24 to 1.46) were positively associated with the decision to treat with EVT. Interventionalists (IRR 1.26, 99% CI 1.01 to 1.56) were more likely to treat patients with MeVO immediately with EVT. In the dominance analysis, factors influencing the decision in favor of EVT were (in order of importance): baseline NIHSS, core volume, alteplase use, patients’ age, and occlusion site.

Conclusions

Most physicians in this survey were interventionalists and would treat patients with MeVO stroke immediately with EVT. This finding supports the need for robust clinical evidence.
Effect of first pass reperfusion on outcome in patients with posterior circulation ischemic stroke
Authors: den Hartog Sanne J , Roozenbeek Bob , Boodt Nikki , Bruggeman Agnetha A E , van Es Adriaan C G M , Emmer Bart J , Majoie Charles B L M , van den Wijngaard Ido R , van Doormaal Pieter Jan , van Zwam Wim H , Lingsma Hester F , Dippel Diederik W J
Published: May 2021

Background

First pass reperfusion (FPR), that is, excellent reperfusion (expanded treatment in cerebral ischemia (eTICI) 2C-3) in one pass, after endovascular treatment (EVT) of an occluded artery in the anterior circulation, is associated with favorable clinical outcome, even when compared with multiple pass excellent reperfusion (MPR). In patients with posterior circulation ischemic stroke (PCS), the same association is expected, but currently unknown. We aimed to assess characteristics associated with FPR and the influence of FPR versus MPR on outcomes in patients with PCS.

Methods

We used data from the MR CLEAN Registry, a prospective observational study. The effect of FPR on 24-hour National Institutes of Health Stroke Scale (NIHSS) score, as percentage reduction, and on modified Rankin Scale (mRS) scores at 3 months, was tested with linear and ordinal logistic regression models.

Results

Of 224 patients with PCS, 45 patients had FPR, 47 had MPR, and 90 had no excellent reperfusion (eTICI <2C). We did not find an association between any of the patient, imaging, or treatment characteristics and FPR. FPR was associated with better NIHSS (−45% (95% CI: −65% to −12%)) and better mRS scores (adjusted common odds ratio (acOR): 2.16 (95% CI: 1.23 to 3.79)) compared with no FPR. Outcomes after FPR were also more favorable compared with MPR, but the effect was smaller and not statistically significant (NIHSS: −14% (95% CI: −51% to 49%), mRS acOR: 1.50 (95% CI: 0.75 to 3.00)).

Conclusions

FPR in patients with PCS is associated with favorable clinical outcome in comparison with no FPR. In comparison with MPR, the effect of FPR was no longer statistically significant. Nevertheless, our data support the notion that FPR should be the treatment target to pursue in every patient treated with EVT.
Predilection for physical activity and body mass index z-score can quickly identify children needing support for a physically active lifestyle
Authors: Longmuir Patricia E. , Prikryl Emil , Rotz Heather L.L. , Boyer Charles , Alpous Anastasia
Published: May 2021

Comprehensive physical literacy assessments can be time-consuming and require a gymnasium space and examiner training. This project sought to identify easy-to-administer tasks, suitable for all physical activity and healthcare settings, which could quickly screen a group of children to identify those most likely to benefit from an in-depth assessment or additional physical literacy support. The 40 potential screening tasks were compared with the Canadian Assessment of Physical Literacy among 226 children (57% female) aged 8 to 12 years. Absolute body mass index z-score above 0.67 or predilection for physical activity less than 31.5/36 points had the highest sensitivity (81% and 83%, respectively) and specificity (45% and 52%, respectively). Predilection less than 31.5 combined with absolute body mass index z-scores achieved 81% sensitivity and 64% sensitivity. When the selected tasks were repeated on a different sample of 71 children (50% female), results were similar with the combination of predilection and absolute body mass index achieving 92% sensitivity and 53% specificity. Predilection for physical activity, absolute body mass index z-score, and a combination of the two are quick and easy screening tasks suitable for all physical activity settings that can identify children likely to need additional support for a physically active lifestyle.

Novelty: Physical literacy screening can be completed in recreation, education, allied health, coaching and healthcare settings. Predilection for physical activity and body mass index z-score quickly identify children needing physical literacy support.
Effects of red-osier dogwood extracts on growth performance, intestinal digestive and absorptive functions, and meat quality of broiler chickens
Authors: Mogire Marion K. , Choi Janghan , Lu Peng , Yang Chongwu , Liu Shangxi , Adewole Deborah , Rodas-Gonzalez Argenis , Yang Chengbo
Published: May 2021

A total of 320 one-day-old Cobb 500 chicks with an initial weight of 48.3 ± 3.3 g·pen−1 were assigned to four dietary treatments with eight replicates provided in three phases for 46 d. The treatments were fed as mash diets and included (1) negative control (NC) corn-soybean basal diet, (2) positive control (PC) basal diet with 30 ppm avilamycin, (3) basal diet supplemented with 1000 ppm red-osier dogwood extracts (RDE1), and (4) basal diet with 3000 ppm red-osier dogwood extracts (RDE2). Results showed reduced jejunal crypt depth in RDE1 and increased villus:crypt ratio in groups (either RDE1 or RDE2) (P < 0.05). Cationic amino acid (AA) transporter mRNA abundance was decreased (P < 0.05) in RDE1, RDE2, and PC treatments, but peptide and neutral AA transporter mRNA abundance were higher (P < 0.05) in RDE2 compared with NC. Apparent ileal digestibility of crude fat was increased in RDE2 and PC compared with NC, whereas AA digestibility was greater in RDE1, RDE2, and PC (P < 0.05). In conclusion, red-osier dogwood had no effect on growth performance, improved the intestinal health and function of broiler chickens, and had no detrimental effects on meat quality.
Glass fission-track ages, composition, and origin of tephra beds in the Upper Cretaceous Kanguk Formation, Banks Island, Arctic Canada
Authors: Westgate John A. , Bray Colin J.
Published: May 2021

More than 50 conspicuous tephra beds occur in the Kanguk Formation on the southwestern coast of Banks Island. Their glass shards are remarkably well preserved and permit comprehensive characterization, offering the potential for reliable, precise correlation of Upper Cretaceous sedimentary rocks across the three major depocentres of the Arctic Archipelago and adjacent northern continental margin: Sverdrup, Banks, and the Beaufort–Mackenzie basins. Twenty-one tephra beds were analyzed; all have a high-K, peraluminous, rhyolitic composition, with quartz, plagioclase, ilmenite, biotite, and zircon as the dominant minerals. Trace-element concentrations, especially low Nb and Ta, show that the parental magmas formed in a continental-margin subduction environment. Glass fission-track ages range from 100 Ma to younger than 60 Ma, and indicate a very low sedimentation rate giving a very condensed sedimentary sequence on southwestern Banks Island — a sequence that may well contain the K–Pg transition. Source calderas are unknown but most likely are situated in east-central Alaska and the central and northern Kuskokwim volcanic belt, some 1000 to 1500 km distant from southwestern Banks Island. It is also possible that some of the very thin tephra beds come from the Okhotsk–Chukotka volcanogenic belt in northeastern Russia.
Biofilm formation of Staphylococcus aureus from milk and expression of the adhesion genes ebpS and cna at different temperatures
Authors: Kroning Isabela Schneid , Ramires Tassiana , Haubert Louise , Rizzi Caroline , Fernandes Meg da Silva , Lopes Graciela Volz , Dellagostin Odir Antônio , Silva Wladimir Padilha da
Published: May 2021

This study investigated the ability of Staphylococcus aureus isolates from milk to form biofilm, through detection of adhesion genes, investigating exopolysaccharide (EPS) production and biofilm formation on polystyrene (PS) and stainless steel (SS) surfaces, and by quantifying the expression of ebpS and cna genes under different temperatures and culture media. Among the 31 isolates, the adhesion genes ebpS and cna were found in 81% and 61% of the isolates, respectively. The screening tests for phenotype revealed that 58% of the isolates were EPS producers, and 45% showed the ability to produce biofilm on PS. Nine of the 31 isolates were selected to verify their ability to form biofilm on SS, of which 3 were non-biofilm producers, 3 were poor biofilm producers, and 3 were moderate biofilm producers. However, all nine isolates produced biofilm on SS, regardless of their phenotypic profile on PS. Reverse-transcriptase quantitative PCR (RT–qPCR) revealed no variation in the expression levels of ebpS and cna genes at different temperatures, except for isolate S24 at 10 °C, for both genes tested. Moreover, RT–qPCR assays revealed that the expression levels of the adhesion genes ebpS and cna are isolate- and temperature-dependent; however, they are independent of the phenotypic biofilm-formation profile.
On the photon-pseudoscalar particle mixing in media and external fields
Authors: Ejlli Damian
Published: May 2021

In this work, I study the mixing of photons with pseudoscalar particles and vice-versa in the presence of an external magnetic field and a pseudoscalar field. I solve exactly for the first time in the literature the equations of motion of the electromagnetic field coupled with a pseudoscalar field in the presence of a constant magnetic field with arbitrary direction with respect to the direction of propagation of the fields in vacuum. In addition, I also solve exactly the equations of motion in a magnetized plasma/gas for perpendicular propagation with respect to the external magnetic field. By finding exact solutions to the equations of motion, I find exact expressions for the transition efficiencies of photons into pseudoscalar particles in different situations. The expressions of the transition efficiencies generalize and correct those previously found in the literature by using approximate WKB methods on solving the equations of motion. In the case when the direction of propagation of fields with respect to the external magnetic field is not perpendicular, a longitudinal state of the electromagnetic field is generated even in a magnetized vacuum. The appearance of the longitudinal electric field state could be used for laboratory searches of pseudoscalar particles such as the axion and/or axion-like particles.
Masking singularities in Weyl gravity and Ricci flows
Authors: Dzhunushaliev Vladimir , Folomeev Vladimir
Published: May 2021

Within vacuum Weyl gravity, we obtain a solution by which, using different choices of the conformal factor, we derive metrics describing (i) a bounce of the universe; (ii) toroidal and spherical wormholes; and (iii) a change in metric signature. It is demonstrated that singularities occurring in these systems are “masked”. We give a simple explanation of the possibility of masking the singularities within Weyl gravity. It is shown that in the first and third cases the three-dimensional metrics form Ricci flows. The question of the possible applicability of conformal Weyl gravity as some phenomenological theory in an approximate description of quantum gravity is discussed.
New and more fractional soliton solutions related to generalized Davey–Stewartson equation using oblique wave transformation
Authors: Raza Nauman , Arshed Saima , Khan Kashif Ali , Baleanu Dumitru
Published: May 2021

The generalized fractional Davey–Stewartson (DSS) equation with fractional temporal derivative, which is used to explore the trends of wave propagation in water of finite depth under the effects of gravity force and surface tension, is considered in this paper. The paper addresses the full nonlinearity of the proposed model. To extract the oblique soliton solutions of the generalized fractional DSS (FDSS) equation is the dominant feature of this research. The conformable fractional derivative is used for fractional temporal derivative and oblique wave transformation is used for converting the proposed model into ordinary differential equation. Two state-of-the-art integration schemes, modified auxiliary equation (MAE) and generalized projective Riccati equations (GPREs) method have been employed for obtaining the desired oblique soliton solutions. The proposed methods successfully attain different structures of explicit solutions such as bright, dark, singular, and periodic solitary wave solutions. The occurrence of these results ensured by the limitations utilized is also exceptionally promising to additionally investigate the propagation of waves of finite depth. The latest found solutions with their existence criteria are considered. The 2D and 3D portraits are also shown for some of the reported solutions. From the graphical representations, it have been illustrated that the descriptions of waves are changed along with the change in fractional and obliqueness parameters.
Depositional conditions at the Aptian pre-salt margins: evidence from quantitative petrography and textural analysis of the Mucuri Member, Espírito Santo Basin, Brazil
Authors: Pantopoulos George , Orita Gustavo Kenji Lacerda , Armelenti Garibaldi , Althaus Camila Eliza , Kuchle Juliano , Scherer Claiton Marlon dos Santos , Rodrigues Amanda Goulart , De Ros Luiz Fernando
Published: May 2021

Aptian siliciclastic onshore deposits of the Mucuri Member are important reservoirs in the Espírito Santo Basin (eastern Brazil). A detailed quantitative petrographical and textural analysis of well core samples was performed in order to unravel their depositional processes and conditions, in relation to previously proposed depositional models. The results allowed differentiation between two groups of sandstone samples, characterized by different textural characteristics associated to different depositional processes and environments within the Mucuri depositional system. Fluvial sandstones are represented by medium- to coarse-grained, poorly sorted arkoses, rich in plutonic rock fragments and feldspar grains, mainly transported by traction. Coastal-lacustrine sandstones correspond to very fine- to fine-grained, moderately sorted micaceous arkoses, mainly transported in suspension. The application of a discriminant function based on grain-size parameters validated previously proposed depositional settings for the studied sample groups. The combination of grain-size and shape data revealed differences in hydraulic equivalence and shape between grains from different depositional settings. In terms of hydraulic equivalence, micas in the fluvial sediments present lower settling velocity values, in contrast to the relatively large mica grains in the coastal sediments, which are hydraulically equivalent with the associated quartz and feldspar grains. The results of this study provide key information regarding depositional conditions (transportation mechanisms, grain-settling velocity and mineral hydraulic fractionation) at the margins of the Aptian pre-salt system, which can constrain the hydrological conditions and the sediment type available for distal lacustrine areas.
Nitrate transport in the chalk vadose zone in Picardy, France
Authors: Surdyk Nicolas , Gourcy Laurence , Bault Violaine , Baran Nicole
Published: May 2021

Since the 1980s, nitrate has been shown to be present in soils and the vadose zone of various types of geological materials years after fertilizer application. In chalk, where the vadose zone is thick, nitrate storage can be considerable and its transport time towards groundwater can be lengthy. In this context, evaluation of the impact of changes in agricultural practices on groundwater quality remains a major question. Improvement of groundwater quality can in certain cases be greatly delayed after the implementation of environmental agricultural practices.

The principal objective of this study is to improve our knowledge of when changes in agricultural practices will have a noticeable effect on groundwater quality. To meet this objective, nitrate concentration profiles were performed in agricultural plots in Picardy (France). A crop marker event was used to calculate the transport velocity of water and associated solutes. This method is useful when other tracers (such as tritium or chloride) cannot be used. Estimated velocities range from 0.51 to 0.54 m a
−1
; these values are similar to those described in similar chalk aquifers.
Advances in conceptualizing transport in chalk aquifers
Authors: Foley Aidan E. , Worthington Stephen R. H.
Published: May 2021

The conceptualizations of matrix, fracture and fissure porosity are important for understanding relative controls on storage and flow of groundwater, and the transport of solutes (and non-aqueous phase liquids) within chalk aquifers. However, these different types of porosity, rather than being entirely distinct, represent elements in a continuum of void sizes contributing to the total porosity of the aquifer. Here we define such a continuum and critically examine the selection of appropriate values of effective porosity, a widely used parameter for mass transport modelling in aquifers. Effective porosity is a transient phenomenon, related to the porosity continuum by the timescales under which mass transport occurs. An analysis of 55 tracer tests and 20 well inflow tests in English Chalk aquifers identifies spatial scaling in groundwater velocity and groundwater flow respectively, which are interpreted within the context of the wider literature on carbonate aquifers globally. We advance transport modelling in the Chalk by developing a fissure aperture velocity mapping method using transmissivity data from existing regional groundwater models, together with the identified transient and spatial scaling phenomena. The results show that chalk aquifers exhibit widespread rapid groundwater flow which may transport contaminants rapidly in almost any setting.
Development of spatial permeability variations in English Chalk aquifers
Authors: Worthington Stephen R. H. , Foley Aidan E.
Published: May 2021

The Cretaceous Chalk in England forms dual-porosity aquifers, with low-permeability matrix and high-permeability networks of fissures, which are predominantly stress-relief fractures that have been enlarged by dissolution. This enlargement is a function of the volume of water that has passed along a fracture (the flowrate effect) and its degree of chemical undersaturation. Feedback effects result in the development of a distinctive permeability structure, with four particular characteristics: (i) troughs in the water table with high transmissivity and convergent groundwater flow; (ii) substantial increases in transmissivities in a downgradient direction; (iii) downgradient decreases in hydraulic gradient; and (iv) discharge from the high-transmissivity zones to the surface commonly at substantial springs. This distinctive self-organized permeability structure occurs throughout unconfined chalk aquifers. Early enlargement of fissures at a depth of 50–100 m below the water table is slow, but is much more rapid close to the water table and in the uppermost bedrock due to non-linear dissolution kinetics. A modelled dissolution profile shows that more than 95% of dissolution takes place in the top 1 m of bedrock, and that enlargement of fissures in the saturated zone results from progressive dissolution occurring over a period of a million years or more.
A Survey of Ambient Intelligence
Authors: Dunne Rob , Morris Tim , Harper Simon
Published: May 2021

Ambient Intelligence (AmI) is the application and embedding of artificial intelligence into everyday environments to seamlessly provide assistive and predictive support in a multitude of scenarios via an invisible user interface. These can be as diverse as autonomous vehicles, smart homes, industrial settings, and healthcare facilities—referred to as Ambient Assistive Living. This survey gives an overview of the field; defines key terms; discusses social, cultural, and ethical issues; and outlines the state of the art in AmI technology, and where opportunities for further research exist. We guide the reader through AmI from its inception more than 20 years ago, focussing on the important topics and research achievements of the past 10 years since the last major survey, before finally detailing the most recents research trends and forecasting where this technology is likely to develop. This survey covers domains, use cases, scenarios, and datasets; cultural concerns and usability issues; security, privacy, and ethics; interaction and recognition; prediction and intelligence; and hardware, infrastructure, and mobile devices. This survey serves as an introduction for researchers and the technical layperson into the topic of AmI and identifies notable opportunities for further research.
Probabilistic Rule Learning Systems
Authors: Salam Abdus , Schwitter Rolf , Orgun Mehmet A.
Published: May 2021

This survey provides an overview of rule learning systems that can learn the structure of probabilistic rules for uncertain domains. These systems are very useful in such domains because they can be trained with a small amount of positive and negative examples, use declarative representations of background knowledge, and combine efficient high-level reasoning with the probability theory. The output of these systems are probabilistic rules that are easy to understand by humans, since the conditions for consequences lead to predictions that become transparent and interpretable. This survey focuses on representational approaches and system architectures, and suggests future research directions.
The Programmable Data Plane
Authors: Michel Oliver , Bifulco Roberto , Rétvári Gábor , Schmid Stefan
Published: May 2021

Programmable data plane technologies enable the systematic reconfiguration of the low-level processing steps applied to network packets and are key drivers toward realizing the next generation of network services and applications. This survey presents recent trends and issues in the design and implementation of programmable network devices, focusing on prominent abstractions, architectures, algorithms, and applications proposed, debated, and realized over the past years. We elaborate on the trends that led to the emergence of this technology and highlight the most important pointers from the literature, casting different taxonomies for the field, and identifying avenues for future research.
Smartphone-Based Indoor Visual Navigation with Leader-Follower Mode
Authors: Xu Jingao , Dong Erqun , Ma Qiang , Wu Chenshu , Yang Zheng
Published: May 2021

Existing indoor navigation solutions usually require pre-deployed comprehensive location services with precise indoor maps and, more importantly, all rely on dedicatedly installed or existing infrastructure. In this article, we present Pair-Navi, an infrastructure-free indoor navigation system that circumvents all these requirements by reusing a previous traveler’s (i.e., leader) trace experience to navigate future users (i.e., followers) in a Peer-to-Peer mode. Our system leverages the advances of visual
simultaneous localization and mapping
(
SLAM
) on commercial smartphones. Visual SLAM systems, however, are vulnerable to environmental dynamics in the precision and robustness and involve intensive computation that prohibits real-time applications. To combat environmental changes, we propose to cull non-rigid contexts and keep only the static and rigid contents in use. To enable real-time navigation on mobiles, we decouple and reorganize the highly coupled SLAM modules for leaders and followers. We implement Pair-Navi on commodity smartphones and validate its performance in three diverse buildings and two standard datasets (TUM and KITTI). Our results show that Pair-Navi achieves an immediate navigation success rate of 98.6%, which maintains as 83.4% even after 2 weeks since the leaders’ traces were collected, outperforming the state-of-the-art solutions by >50%. Being truly infrastructure-free, Pair-Navi sheds lights on practical indoor navigations for mobile users.
Bipolar (Bio)electroanalysis
Authors: Bouffier Laurent , Zigah Dodzi , Sojic Neso , Kuhn Alexander
Published: May 2021

This contribution reviews a selection of the most recent studies on the use of bipolar electrochemistry in the framework of analytical chemistry. Despite the fact that the concept is not new, with several important studies dating back to the middle of the last century, completely novel and very original approaches have emerged over the last decade. This current revival illustrates that scientists still (re)discover some exciting virtues of this approach, which are useful in many different areas, especially for tackling analytical challenges in an unconventional way. In several cases, this “wireless” electrochemistry strategy enables carrying out measurements that are simply not possible with classic electrochemical approaches. This review will hopefully stimulate new ideas and trigger scientists to integrate some aspects of bipolar electrochemistry in their work in order to drive the topic into yet unexplored and eventually completely unexpected directions.
Stabilized Nanocrystalline Alloys: The Intersection of Grain Boundary Segregation with Processing Science
Authors: Perrin Alice E. , Schuh Christopher A.
Published: May 2021

Processing science for nanocrystalline metals has largely focused on far-from-equilibrium methods that can generate many grain boundaries with excess defect energy. Conversely, the science of stabilizing nanocrystalline alloys has largely focused on the lowering of that excess defect energy through grain boundary segregation, bringing nanocrystalline structures closer to equilibrium. With increasing technological adoption of stabilized nanocrystalline alloys, there is a substantial need for research at the intersection of these two fields. This review lays out the basic thermodynamic issues of the two subfields and surveys the literature on the most common processing methods, including severe plastic deformation, ball milling, physical vapor deposition, and electrodeposition. We provide an overview of studies that have examined grain boundary segregation through each of these methods and identify general themes. We conclude that there is substantial scope for more systematic work at the intersection of these fields to understand how nonequilibrium processing affects grain boundary segregation.