bluuebunny/crossref_metadata_2025 huggingface dataset:
Light amplification via PbS quantum dots-doped tapered fiber coupler: model and theory
Authors: Pakarzadeh Hassan , Karimi Mohammad Javad , Mohammadi Zeinab , Taghizadeh Mostafa , Bozorgzadeh Forough
Published: October 2020

In this paper, the gain engineering of a semiconductor quantum dots fiber amplifier (SQDFA) is studied. The optical amplification is realized by exciting the PbS quantum dots coated around the tapered single-mode fiber coupler with an evanescent wave. The gain spectra and saturation properties of the SQDFA are obtained via solving the rate and coupled power equations based on the two-level model. Then, the effect of the signal wavelength, pump power and amplifier length on the saturation characteristics is numerically simulated. The obtained results show that the proposed model is in a good agreement with the previous experimental results. Unique characteristics of the SQDFA such as the broadband optical gain and smooth bandwidth are of great interest for dense wavelength-division multiplexing systems. Therefore, the proposed model show promising applications in the future fiber-optic communications.
Controlling photonic spin Hall effect in graphene-dielectric structure by optical pumping
Authors: Dong Peng , Cheng Jie , Da Haixia , Yan Xiaohong
Published: October 2020

The photonic spin Hall effect (SHE) provides an effective way to manipulate the spin-polarized photons. However, the spin-dependent splitting is very tiny due to the weak spin–orbit coupling, and previous investigations for enhancing this phenomenon have some serious limitations (e.g. inconvenient to tune, inadequate attention in terahertz region). Therefore, controlling and enhancing the photonic SHE in a flexible way is highly desirable, especially for terahertz region. In this contribution, we propose a method to manipulate the photonic SHE by taking advantage of tunable optical properties of graphene via weak optical pumping. We find that photonic SHE of graphene-dielectric structure in terahertz region is quite sensitive to the pumping power. The spin shift for H polarized incident beam can reach its upper limitation under the optimal pumping power, which is related to the zero value of the real part of graphene conductivity. These findings may provide a new degree of freedom for the design of tunable spin-based photonic devices in the future.
New quantum algorithms to solve the linear equations
Authors: He Rui , Zhang Gang
Published: October 2020

Based on the infinite dimensional variable quantum system, we propose two quantum algorithms to solve the linear equations. Both algorithms can be considered as infinite-dimensional versions of the HHL algorithm. From this we can see that the infinite dimensional quantum variable system as a physical resource can be widely popularized in quantum computing.
Influence of mode coupling on three spatially multiplexed channels in multimode graded index plastic optical fibers
Authors: Savović S , Djordjevich A , Simović A , Drljača B
Published: October 2020

The influence of mode coupling on three-channel spatial division multiplexing capability in multimode graded index plastic optical fibers is investigated by solving the power flow equation. Our numerical results show that mode coupling significantly limits the fiber length at which the spatial division multiplexing can be realized with a minimal crosstalk between three neighbor spatial optical channels. Three spatial channels in the multimode graded index plastic optical fiber can be employed with a minimal crosstalk up to the fiber length of 3.5 m, which is about 12.5% of the coupling length (fiber length where equilibrium mode distribution is achieved). Such characterization of multimode graded index plastic optical fibers should be considered in designing an optical fiber transmission system for space division multiplexing, particularly for small office networking.
The difference logical operation for images in optical echo holography
Authors: Akhmedshina E N , Sakhbieva A R , Nefediev L A , Nefedyev Y A , Andreev A O
Published: October 2020

In this paper, we consider the implementation of logical operations on images using the accumulated long-lived echo hologram. It is shown that the accumulated echo hologram could be used for the implementation of the set difference logical operation.
Far off-shore wind energy-based hydrogen production: Technological assessment and market valuation designs
Authors: Woznicki M , Le Solliec G , Loisel R
Published: October 2020

This article provides a techno-economic study on coupled offshore wind farm and green hydrogen production via sea water electrolysis (OWF-H2). Offshore wind energy, wind farms (OWF) and water electrolysis (WE) technologies are described. MHyWind (the tool used to perform simulations and optimisations of such plants) is presented, as well as the models of the main components in the study. Three case studies focus on offshore wind farms, either standalone or connected to the grid via export cables, coupled with a battery and electrolysis systems either offshore or onshore. Exhaustive searches and optimisations performed allowed for rules of thumb to be derived on the sizing of coupled OWF-H2 plants, that minimize costs of hydrogen production (LCoH2, in €/kgH2): Non-connected OWF-H2, coupled to a battery, offers the lowest LCoH2, without the costs of H2 transportation, when compared to cases where the WE is installed onshore and connected to the OWF. Using a simple power distribution heuristic, increasing the number of installed WE allows the system to take advantage of more OWF energy but doesn’t improve plant efficiency, whereas a battery always does. Finally, within the scope of this study, it is observed that power ratios of optimized plant architectures (leading to the lowest LCoH2) are between 0.8-0.9 for PWE/POWF and 0.3-0.35 for PBattery/POWF.
Applications and platforms in digitalisation of wind farm O&M – community feedback and survey results
Authors: Berkhout V , Machill B , Reintanz L
Published: October 2020

Achieving performance optimisation and cost savings by advanced data analysis techniques and improved digital communication is a significant focus of wind farm operators and research organisations often framed under the terms IoT or Industry 4.0. Within the research project ‘ModernWindABS’, Fraunhofer IEE has conducted a twofold approach to identify new applications using modern methods that will innovate operation and maintenance processes. Based on a systematic structure of O&M processes and mathematic methods, innovative applications were identified and evaluated in expert workshops. Separately a survey among wind industry professionals with the focus on innovative applications through digital platforms has been conducted in partnership with German industry associations. From both approaches, applications, that enable failure risk monitoring, turn out as the highest priorities from the professionals consulted. Additionally, the survey results yield insights on participants’ expectations on benefits and financial contribution per organisational role and preferences regarding the platform setup and points out gaps between these expectations and current platform service designs. It further identifies the main barriers to the broader use of platforms, of which organisational and legal obstacles seem to outweigh technical problems.
On Stochastic Reduced-Order and LES-based Models of Offshore Wind Turbine Wakes
Authors: Paskyabi Mostafa Bakhoday , Krutova Maria , Nielsen Finn Gunnar , Reuder Joachim , Guernaoui Omar El
Published: October 2020

In this paper, the primary objective is to investigate flow structures in the wake of wind turbines based on applying a truncated Proper Orthogonal Decomposition (POD) approach. This scheme decomposes the three-dimensional velocity fields produced by the high-fidelity PArallelized LES Model (PALM) into a number of orthogonal spatial modes and time-dependent weighting coefficients. PALM has been combined with an actuator disk model with rotation to incorporate the effects of a turbine array. The time-dependent deterministic weights from applying the POD scheme are replaced by stochastic weights, estimated from two independent stochastic techniques that aim to account for unresolved small-scale features for a number of POD modes. We then reconstruct the flow field by a small number of stochastic modes to investigate how well the applied stochastic methodologies can reproduce the flow field compared to the original LES results.
A Numerical Study on the Effect of Wind Turbine Wake Meandering on the Power Production of Hywind Tampen
Authors: Tenggren Endre , Erik Olsen Lars , Andr`e Johansen Daniel , Bracchi Tania
Published: October 2020

The purpose of the study is to show the importance of wake meandering effect with regard to power production, in terms of annual energy production (AEP), and velocity deficit for wind turbines affected by wake meandering. A simplified economical and environmental analysis is also presented. A replica of Equinor’s layout for Hywind Tampen wind farm, referred to as the original layout, is made and used as a basis for comparison. An alternative configuration is produced through a pragmatical optimization process, applying the SIMA-DIWA software, which reduces the effect of wake meandering on the downstream wind turbines, when the wind approaches from the most frequent direction. To show the aerodynamic effects of applying greater spacing between turbines, an enhanced version of Hywind Tampen is also presented. The main findings of the project correlate greater wake effect meandering for wind turbine configurations spread over a smaller area. The estimated annual energy production for the three configurations is 488.5 GWh for the original, 497.6 GWh for the up-scaled and 486.2 GWh for the alternative configuration, respectively. Furthermore, the optimization process revealed that a reduction in turbine distance can contribute to reduced wake effect in particular cases.
Observations from hydrodynamic testing of a flexible, large-diameter monopile in irregular waves
Authors: Bachynski E E , Thys M , Dadmarzi F H
Published: October 2020

As the offshore wind industry moves toward larger wind turbines and deeper water, wave-induced loads on large-diameter monopiles are of increasing importance for ultimate limit state design checks. The combination of a relatively large diameter with steep waves in intermediate water depth presents challenges for numerical methods, and small-scale hydrodynamic testing of monopiles is therefore a necessary step in reducing the uncertainties in numerical analyses. Here, we aim to summarize the experimental observations in a new set of tests carried out with a flexible monopile wind turbine, and to understand the similarities and differences between these results and previous studies. Compared to previous studies, the present tests consider a larger monopile diameter and hub height, and include a larger number of realizations and repetitions. The distribution of extreme values and the contributions from different structural modes are studied. These experimental results provide insight into the physical effects which must be accurately captured by numerical tools that are used in design.
Our Moment of Truth: The Social Contract Realized?
Authors: Lubchenco Jane , Rapley Chris
Published: October 2020

Much has changed in the two decades since I (JL) proposed that scientists should re-examine their obligations to society in order to serve society better. Today, more environmental scientists are actively sharing their science broadly, conducting use-inspired science (sensu Stokes) in addition to basic science, engaging with society, and crafting solutions to problems not just diagnosing them—all very welcome and exciting developments. For the most part, however, environmental scientists have taken on these extra duties because they believed it was the right thing to do and despite the considerable impediments that exist within academia. But make no mistake, the culture of academia continues to impede progress. As a result, although the above actions have had demonstrable effect, their collective impact falls far short of what is needed if society is to tackle effectively the disruption underway due to climate change, ocean acidification, biodiversity loss, pandemics, and more. Actions by individuals can take us only so far. To truly help society meet its grand challenges, environmental scientists must now make a quantum leap in engagement with society. It is time for strategic, collective action to change the culture of academia and create the enabling conditions for science to serve society better.
Vascular plant species response to warming and elevated carbon dioxide in a boreal peatland
Authors: McPartland Mara Y , Montgomery Rebecca A , Hanson Paul J , Phillips Jana R , Kolka Randy , Palik Brian
Published: October 2020

Peatlands store a significant amount of terrestrial organic carbon in plant biomass and soils. The Spruce and Peatland Responses Under Changing Environments (SPRUCE) project is a warming and elevated carbon dioxide (eCO2) experiment designed to test how the carbon sequestration and storage capacity of peatland ecosystems will respond to climate change. Here, we report changes in the vascular plant community that have occurred during the first five years of SPRUCE. We tracked species composition, diversity, and aboveground net primary production (ANPP) in chambers warmed at a wide range of temperatures (+0, +2.25, +4.5, +6.75, +9 °C), and two CO2 levels (~400 [ambient] and 900 parts per million). We observed an increase in aboveground vascular plant biomass accumulation, due primarily to an increase in shrub abundance. Overall species diversity decreased substantially, likely due in part to shading by increases in shrub density. The main driver of change in the vascular plant community was temperature, with minimal effects of CO2 evident. These results indicate an overall increase in ANPP with warming, but highlight the importance of interactions between direct (warming) and indirect (competition) effects in determining how boreal peatlands will respond to climate change.
What explains the variation in dam impacts on riverine macroinvertebrates? A global quantitative synthesis
Authors: Wang Jun , Ding Chengzhi , Heino Jani , Jiang Xiaoming , Tao Juan , Ding Liuyong , Su Wan , Huang Minrui , He Daming
Published: October 2020

Dams have fragmented rivers and threatened aquatic biodiversity globally. However, the findings regarding dam impacts on riverine macroinvertebrates vary across regions and taxa. We conducted a global meta-analysis to quantify the effects of dams on macroinvertebrate assemblages (i.e. species richness and abundance) based on 3849 data points extracted from 54 publications. Responses of macroinvertebrates to dams varied among climatic zones, dam altitudes, dam sizes (i.e. height), downstream distances from the dams, and taxonomic groups. The overall effect size of dams on macroinvertebrate richness was negative, while that of dams on abundance was positive but varied among different dam types. Richness reductions were most pronounced in cold regions and high-altitude regions and were least pronounced in tropical regions and low-altitude regions, while abundance increases were more obvious in tropical regions and low-altitude regions. Macroinvertebrate richness reduction and abundance increase were coupled (i.e. when the richness slightly decreased, the increase in abundance was more significant, and vice versa) under the influence of dams across different climatic zones, altitudes, dam heights, and downstream distances from the dams. Furthermore, different taxonomic groups responded variably to dams, with stoneflies (Plecoptera), caddisflies (Trichoptera) and true bugs (Hemiptera) being the most sensitive groups (i.e. significant reduction in richness) among the taxa examined. Macroinvertebrate richness reductions were primarily attributed to changes in downstream substrate composition (i.e. from coarse to fine substrates), while abundance increases were potentially caused by replacements among taxa at downstream sites. Collectively, our results contribute to improving the prediction of the effects of dams on riverine macroinvertebrate assemblages and are valuable for guiding assessment and monitoring of river ecosystems, as well as sustainable dam development, planning and restoration.
Holocene peat humification and carbon dynamics in the Westerlies-influenced Northwest China
Authors: Li Yinbo , Chen Liang , Ran Min
Published: October 2020

Understanding peat carbon dynamics in the past is of significance, given the uncertainties as to whether there will be an increase or a reduction in carbon as a result of future climate change. Studies of peat carbon dynamics have primarily been conducted in monsoon-influenced China. However, data relating to carbon dynamics in peat deposits has not yet been investigated in Westerlies-influenced Northwest China (NWC). In this study, the Holocene carbon accumulation rate (CAR) is explored at the Tuolehaite peat core, with a mean rate of growth of 2.4 yr mm−1, 0.4 mm yr−1, in the high-elevation Altai Mountains within NWC. Its CAR shows a decreasing trend, ranging from 4.8 to 68.8 g C m−2 yr−1, with a mean of 28.0 g C m−2 yr−1 since the Holocene epoch. Comparisons of the CAR in the Westerlies-influenced NWC with that in the monsoon-influenced Qinghai-Tibetan Plateau, Northeast China, and South China, reveal that the Holocene CAR trend in relatively high-elevation peat deposits (e.g. Tuolehaite Peat and Hongyuan Peat) is opposite to that found in relatively low-elevation peat deposits (e.g. Hani Peat and Dahu Peat). Different driving factors (temperature and precipitation) of CAR could be responsible for these opposing trends. To be specific, temperature is the main driving factor influencing the CAR in relatively high-elevation peat deposits, whereas precipitation is the key driving factor controlling the CAR in relatively low-elevation peat deposits. Our work indicates that comprehensive investigations into peat CARs in both Westerlies-influenced and monsoon-influenced regions contribute to an understanding of the peat CAR pattern in China as a whole.
Effects of cooling method and elements segregation on the martensite-pearlite banded structure of high carbon bearing steel
Authors: Wang Yun-long , Yu Wei , Chen Yin-li
Published: October 2020

In this study, the effects of the cooling method and alloying element segregation on the abnormal zonal structure of high-carbon bearing steel were investigated by reheating, controlled rolling, and controlled cooling of the sample. The microstructure and alloy segregation characteristics of the abnormal strip structure in the hot-rolled plate of the steel were revealed by optical microscopy, scanning electron microscopy, transmission electron microscopy, and electron probe x-ray microanalysis. The JMatPro thermodynamic software was used to examine the relationship between the alloy elements and banded structure defects of the hot-rolled sheet and analyse the causes of the defects and their elimination methods. The results show distinct positive segregation of Cr/Mn and negative segregation of C in martensite–pearlite banded structure defects in hot-rolled plates. The martensite–pearlite banded structure is formed by the interaction between the cooling rate and the segregation of alloying elements after hot rolling. Studies have found that segmented cooling (slow cooling–air cooling) can eliminate the martensite–pearlite banded structure.
Bi2Se3, Bi2Te3 quantum dots-sensitized rutile TiO2 nanorod arrays for enhanced solar photoelectrocatalysis in azo dye degradation
Authors: Zhou Guanda , Zhao Ting , Wang Oumin , Xia Xin , Pan Jia Hong
Published: October 2020

Rutile TiO2 nanorod arrays vertically aligned on conductive fluorine-doped tin oxide glass are optimized for photocatalysis in terms of the density and diameter of nanorods by tuning the concentration of Ti precursor and reaction time during the hydrothermal process. Quantum dots (QDs) of V2VI3( V = Bi; VI = Se, Te) topographic insulators are then employed as sensitizers to enhance the visible-light response of TiO2. Electrochemical measurements show that the decoration of Bi2Se3 or Bi2Te3 significantly increases the photocurrent due to the enhanced light harvesting properties and the charge carrier separation capability mediated by the topographic isolation effect of V2VI3 QDs. Photoelectrocatalytic (PEC) activity evaluation is conducted towards the decoloration of azo dyes, including methyl orange and methylene blue under the sunlight irradiation. The elaborated Bi2Se3/TiO2 nanorod array exhibits the superior PEC performances, presenting shows great potentials in environmental remediation.
How do we share data in COVID-19 research? A systematic review of COVID-19 datasets in PubMed Central Articles
Authors: Zuo Xu , Chen Yong , Ohno-Machado Lucila , Xu Hua
Published: October 2020

Objective

This study aims at reviewing novel coronavirus disease (COVID-19) datasets extracted from PubMed Central articles, thus providing quantitative analysis to answer questions related to dataset contents, accessibility and citations.

Methods

We downloaded COVID-19-related full-text articles published until 31 May 2020 from PubMed Central. Dataset URL links mentioned in full-text articles were extracted, and each dataset was manually reviewed to provide information on 10 variables: (1) type of the dataset, (2) geographic region where the data were collected, (3) whether the dataset was immediately downloadable, (4) format of the dataset files, (5) where the dataset was hosted, (6) whether the dataset was updated regularly, (7) the type of license used, (8) whether the metadata were explicitly provided, (9) whether there was a PubMed Central paper describing the dataset and (10) the number of times the dataset was cited by PubMed Central articles. Descriptive statistics about these seven variables were reported for all extracted datasets.

Results

We found that 28.5% of 12 324 COVID-19 full-text articles in PubMed Central provided at least one dataset link. In total, 128 unique dataset links were mentioned in 12 324 COVID-19 full text articles in PubMed Central. Further analysis showed that epidemiological datasets accounted for the largest portion (53.9%) in the dataset collection, and most datasets (84.4%) were available for immediate download. GitHub was the most popular repository for hosting COVID-19 datasets. CSV, XLSX and JSON were the most popular data formats. Additionally, citation patterns of COVID-19 datasets varied depending on specific datasets.

Conclusion

PubMed Central articles are an important source of COVID-19 datasets, but there is significant heterogeneity in the way these datasets are mentioned, shared, updated and cited.
Inferring TF activities and activity regulators from gene expression data with constraints from TF perturbation data
Authors: Ma Cynthia Z , Brent Michael R
Published: October 2020

Motivation

The activity of a transcription factor (TF) in a sample of cells is the extent to which it is exerting its regulatory potential. Many methods of inferring TF activity from gene expression data have been described, but due to the lack of appropriate large-scale datasets, systematic and objective validation has not been possible until now.

Results

We systematically evaluate and optimize the approach to TF activity inference in which a gene expression matrix is factored into a condition-independent matrix of control strengths and a condition-dependent matrix of TF activity levels. We find that expression data in which the activities of individual TFs have been perturbed are both necessary and sufficient for obtaining good performance. To a considerable extent, control strengths inferred using expression data from one growth condition carry over to other conditions, so the control strength matrices derived here can be used by others. Finally, we apply these methods to gain insight into the upstream factors that regulate the activities of yeast TFs Gcr2, Gln3, Gcn4 and Msn2.

Availability and implementation

Evaluation code and data are available at https://doi.org/10.5281/zenodo.4050573.

Supplementary information

Supplementary data are available at Bioinformatics online.
Antimicrobial Resistance in Typhoidal Salmonella: Surveillance for Enteric Fever in Asia Project, 2016–2019
Authors: Qamar Farah N , Yousafzai Mohammad T , Dehraj Irum F , Shakoor Sadia , Irfan Seema , Hotwani Aneeta , Hunzai Muhammad J , Thobani Rozina S , Rahman Najeeb , Mehmood Junaid , Hemlock Caitlin , Memon Ashraf M , Andrews Jason R , Luby Stephen P , Garrett Denise O , Longley Ashley T , Date Kashmira , Saha Samir K
Published: October 2020

Background

Clinicians have limited therapeutic options for enteric as a result of increasing antimicrobial resistance, and therefore typhoid vaccination is recommended as a preventive measure. As a part of the Surveillance for Enteric Fever in Asia Project (SEAP), we investigated the extent measured the burden of antimicrobial resistance (AMR) among confirmed enteric fever cases in Bangladesh, Nepal, and Pakistan.

Methods

From September 2016–September 2019, SEAP recruited study participants of all age groups from its outpatient, inpatient, hospital laboratory, laboratory network, and surgical sites who had a diagnosis of febrile illness that was either suspected or blood culture confirmed for enteric fever. Antimicrobial resistance of isolates was determined by disc diffusion using Clinical and Laboratory Standard Institute cut-off points. We reported the frequency of multidrug resistance (MDR)(resistance to ampicillin, cotrimoxazole, and chloramphenicol), extensive drug resistance (XDR) (MDR plus non-susceptible to fluoroquinolone and any 3rd generation cephalosporins), and fluoroquinolone (FQ) and azithromycin non-susceptibility.

Results

We enrolled 8,705 blood culture confirmed enteric fever cases: 4,873 (56%) from Bangladesh, 1,602 (18%) from Nepal and 2,230 (26%) from Pakistan. Of these, 7,591 (87%) were Salmonella Typhi and 1114 (13%) were S. Paratyphi. MDR S. Typhi was identified in 17% (701/4065) of isolates in Bangladesh, and 1% (19/1342) in Nepal. In Pakistan, 16 % (331/2084) of S. Typhi isolates were MDR, and 64% (1319/2074) were XDR. FQ nonsusceptibility among S. Typhi isolates was 98% in Bangladesh, 87% in Nepal, and 95% in Pakistan. Azithromycin non-susceptibility was detected in 77 (2%) in Bangladesh, 9 (.67%) in Nepal and 9 (.59%) isolates in Pakistan. In Pakistan, three (2%) S. Paratyphi isolates were MDR; no MDR S. Paratyphi was reported from Bangladesh or Nepal.

Conclusions

Although AMR against S. Paratyphi was low across the three countries, there was widespread drug resistance among S. Typhi, including FQ non-susceptibility and the emergence of XDR S. Typhi in Pakistan, limiting treatment options. As typhoid conjugate vaccine (TCV) is rolled out, surveillance should continue to monitor changes in AMR to inform policies and to monitor drug resistance in S. Paratyphi, for which there is no vaccine.
Cost-Effectiveness of an Adjuvanted Hepatitis B Vaccine (HEPLISAV-B) in Patients With Inflammatory Bowel Disease
Authors: Corral Juan E , Kwon Joshua Y , Caldera Freddy , Pungpapong Surakit , Spaulding Aaron C , Borah Bijan J , Moriarty James P , Farraye Francis A
Published: October 2020

Background

Compare the cost-effectiveness of 2 recombinant hepatitis B virus (HBV) vaccines in patients with inflammatory bowel disease (IBD).

Methods

Markov models were developed for 2 IBD cohorts: (1) 40-year-old patients prior to starting IBD treatment and (2) 40-year-old patients already receiving therapy. Cohort A received full vaccination series, cohort B had primary vaccine failure and received a vaccine booster. Two vaccines were compared: adjuvanted HEPLISAV-B and nonadjuvanted Engerix-B. Clinical probabilities of acute hepatitis, chronic hepatitis, cirrhosis, fulminant hepatic failure and death, treatment costs, and effectiveness estimates were obtained from published literature. A lifetime analysis and a US payer perspective were used. Probabilistic sensitivity analyses were performed for different hypothetical scenarios.

Results

Analysis of cohort A showed moderate cost-effectiveness of HEPLISAV-B ($88,114 per quality-adjusted life year). Analysis of cohort B showed increased cost-effectiveness ($35,563 per quality-adjusted life year). Changing Engerix-B to HEPLISAV-B in a hypothetical group of 100,000 patients prevented 6 and 30 cases of acute hepatitis; and 4 and 5 cases of chronic hepatitis annually for cohorts A and B, respectively. It also prevented 1 and 2 cases of cirrhosis, and 1 and 2 deaths over 20 years for each cohort. Cost-effectiveness was determined by vaccination costs, patient age, and progression rate from chronic hepatitis to cirrhosis.

Conclusions

HEPLISAV-B is cost-effective over Engerix-B in patients receiving immunosuppressive therapy for IBD. Benefits increase with population aging and lower costs of vaccines. We advocate measuring levels of HBV antibodies in patients with IBD and favor adjuvanted vaccines when vaccination is needed.
Climate extremes, variability, and trade shape biogeographical patterns of alien species
Authors: Liu Xuan , Rohr Jason R , Li Xianping , Deng Teng , Li Wenhao , Li Yiming
Published: October 2020

Understanding how alien species assemble is crucial for predicting changes to community structure caused by biological invasions and for directing management strategies for alien species, but patterns and drivers of alien species assemblages remain poorly understood relative to native species. Climate has been suggested as a crucial filter of invasion-driven homogenization of biodiversity. However, it remains unclear which climatic factors drive the assemblage of alien species. Here, we compiled global data at both grid scale (2,653 native and 2,806 current grids with a resolution of 2° × 2°) and administrative scale (271 native and 297 current nations and sub-nations) on the distributions of 361 alien amphibians and reptiles (herpetofauna), the most threatened vertebrate group on the planet. We found that geographical distance, a proxy for natural dispersal barriers, was the dominant variable contributing to alien herpetofaunal assemblage in native ranges. In contrast, climatic factors explained more unique variation in alien herpetofaunal assemblage after than before invasions. This pattern was driven by extremely high temperatures and precipitation seasonality, 2 hallmarks of global climate change, and bilateral trade which can account for the alien assemblage after invasions. Our results indicated that human-assisted species introductions combined with climate change may accelerate the reorganization of global species distributions.
Distinct Adult Eclosion Traits of Sibling SpeciesRhagoletis pomonellaandRhagoletis zephyria(Diptera: Tephritidae) Under Laboratory Conditions
Authors: Yee Wee L , Goughnour Robert B , Feder Jeffrey L
Published: October 2020

Closely related phytophagous insects that specialize on different host plants may have divergent responses to environmental factors. Rhagoletis pomonella (Walsh) and Rhagoletis zephyria Snow (Diptera: Tephritidae) are sibling, sympatric fly species found in western North America that attack and mate on plants of Rosaceae (~60 taxa) and Caprifoliaceae (three taxa), respectively, likely contributing to partial reproductive isolation. Rhagoletis zephyria evolved from R. pomonella and is native to western North America, whereas R. pomonella was introduced there. Given that key features of the flies’ ecology, breeding compatibility, and evolution differ, we predicted that adult eclosion patterns of the two flies from Washington State, USA are also distinct. When puparia were chilled, eclosion of apple- and black hawthorn-origin R. pomonella was significantly more dispersed, with less pronounced peaks, than of snowberry-origin R. zephyria within sympatric and nonsympatric site comparisons. Percentages of chilled puparia that produced adults were ≥67% for both species. However, when puparia were not chilled, from 13.5 to 21.9% of apple-origin R. pomonella versus only 1.2% to 1.9% of R. zephyria eclosed. The distinct differences in eclosion traits of R. pomonella and R. zephyria could be due to greater genetic variation in R. pomonella, associated with its use of a wider range of host plants than R. zephyria.
A case report of a coronary artery fistula to coronary sinus with giant aneurysm: risk does not end with repair
Authors: Poretti Giulia , Lo Rito Mauro , Varrica Alessandro , Frigiola Alessandro
Published: October 2020

Background

Isolated coronary arteriovenous fistulas are extremely rare, accounting for 0.08–0.4% of all congenital heart disease. Closure of the fistula is recommended in cases of large dimensions, relevant left–right shunt, or ischaemic events. Thrombosis of the coronary aneurysms may occur as a postoperative complication.

Case summary

We report a case of a coronary fistula between the circumflex artery and coronary sinus with giant aneurysm. After a failed percutaneous closure attempt, the patient was surgically treated without major postoperative complications. Despite therapeutic anticoagulation and antiplatelet therapy, she presented at clinical follow-up with thrombosis of the dilated coronary artery without signs or symptoms of ischaemia.

Discussion

Management of coronary artery fistula may be challenging in cases in which initial percutaneous closure is unsuccessful. This particular case also highlights the importance of close follow-up, despite optimal therapy, to detect potentially lethal complications related to the low flow in the dilated coronary aneurysm.
His bundle pacing capture threshold stability during long-term follow-up and correlation with lead slack
Authors: Beer Dominik , Subzposh Faiz A , Colburn Shaun , Naperkowski Angela , Vijayaraman Pugazhendhi
Published: October 2020

Aims

His bundle pacing (HBP) is the most physiologic form of pacing. Long-term HBP capture threshold stability and its relation to lead characteristics at the time of implantation have not been adequately described. The aim of this study was to characterize HB capture threshold in follow-up and to identify potential lead characteristics predictive of lead capture instability.

Methods and results

Consecutive patients with successful HBP for bradycardia indications were identified from the Geisinger HBP registry. His bundle capture thresholds, baseline comorbidities, and radiographic lead slack characteristics were analysed. An increase in HB capture threshold ≥1 V above implant values at any time during follow-up was tracked. Forty-four of the 294 studied (15%) experienced HB capture threshold increase by ≥ 1 V. Threshold increase was seen early (41% by 8 weeks, 66% by 1 year). Eighteen (6%) patients required lead revision in follow-up. Abnormal slack shape was associated with a trend toward capture threshold increase [hazard ratio (HR) 2.07; 95% confidence interval (CI) 0.9–4.6; P = 0.08]. Non-perpendicular angle of lead insertion on radiography was associated with the capture threshold increase (HR 2.81, 95% CI 1.4–5.8; P < 0.01).

Conclusion

His bundle capture threshold remains stable in the majority (85%) of patients. Implant characteristics may predict the threshold rise. Further evaluation of the aetiology of threshold increase and design changes in lead and delivery systems may lead to chronically stable capture thresholds.
Lithospheric dynamics in the vicinity of the Tengchong volcanic field (southeastern margin of Tibet): an investigation usingPreceiver functions
Authors: Peng Hengchu , Badal José , Hu Jiafu , Yang Haiyan , Liu Benyu
Published: October 2020

Tengchong volcanic field (TVF) in the northern Indochina block lies in a critical area for understanding complex regional dynamics associated with continent–continent convergence between the Indian and Eurasian plates, including northeastward compression generated by subduction of the Indian Plate beneath the Burma Arc, and southeastward lateral extrusion of the crust from below central Tibet. We gathered 3408 pairs of P receiver functions with different frequencies and calculated the splitting parameters of the Moho-converted Pms phase. An anisotropic H-κ stacking algorithm was used to determine crustal thickness and Vp/Vs ratios. We also inverted for the detailed S-velocity structure of the crust and upper mantle using a two-step inversion technique. Finally, we mapped the topography of the lithosphere–asthenosphere boundary. Results show fast-wave polarization directions with a dominant NE–SW orientation and delay times varying between 0.19 and 1.22 s, with a mean of 0.48 ± 0.07 s. The crustal Vp/Vs ratio varies from 1.68 to 1.90 and shows a maximum value below the central part of the TVF, where there is relatively thin crust (∼35–39 km) and a pronounced low-velocity anomaly in the middle–lower crust. The depth of the lithosphere–asthenosphere boundary ranges from 53 to 85 km: it is relatively deep (∼70–85 km) in the vicinity of the TVF and relatively shallow in the south of the study area. In the absence of low shear wave velocity in the upper mantle below the TVF, we propose that the low-velocity anomaly in the lower crust beneath the TVF derives from the upper mantle below the neighbouring Baoshan block.
Fecal Calprotectin Is Highly Effective to Detect Endoscopic Ulcerations in Crohn’s Disease Regardless of Disease Location
Authors: Buisson Anthony , Mak Wing Yan , Andersen Michael J , Lei Donald , Pekow Joel , Cohen Russell D , Kahn Stacy A , Pereira Bruno , Rubin David T
Published: October 2020

Background

As the reliability of fecal calprotectin (Fcal) remains debatable to detect endoscopic ulcerations in patients with pure ileal Crohn’s disease (CD), we aimed to compare its performances with those observed in patients with colonic or ileocolonic location.

Methods

Using a prospectively maintained database, we analyzed 123 CD patients with Fcal measurement and ileocolonoscopy performed within 1 month with no therapeutic intervention during this interval. Receiver operating characterstic curves (ROC) were used to determine the best Fcal threshold to detect endoscopic ulcerations, taking into account the clinical relevance and usual recommended indices. Sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were presented with 95% confidence intervals.

Results

The mean Fcal level was significantly higher in patients with endoscopic ulcerations in the L1 group (P = 0.025) and the L2-L3 group (P < 0.001). Using ROC curves, Fcal >200 µg/g and Fcal >250 µg/g were the best thresholds to detect endoscopic ulcerations in the L1 group (sensitivity = 75.0, 95% CI, 47.6–92.7; specificity = 87.5, 95% CI, 67.6–97.3; PPV = 80.0, 95% CI, 51.9–95.7; and NPV = 84.0; 95% CI, 63.9–95.5) and in the L2-L3 group (sensitivity = 84.1 95% CI, 69.9–93.4; specificity = 74.4, 95% CI, 57.9–87.0; PPV = 78.7, 95% CI, 64.3–89.3, and NPV = 80.6, 95% CI, 64.0–91.8), respectively. We compared the AUC between L1 and L2-L3 groups, and no difference was shown (0.89 vs 0.84, respectively, P = 0.46). We also compared 2-by-2 sensitivity, specificity, PPV, NPV, and accuracy and we did not observe any significant difference.

Conclusion

Fecal calprotectin is highly effective to detect endoscopic ulcerations regardless of CD location but requires a lower cutoff value in patients with pure ileal involvement.
Comparison of left ventricular unloading strategies on venoarterial extracorporeal life support
Authors: Hasde Ali İhsan , Sarıcaoğlu Mehmet Cahit , Dikmen Yaman Nur , Baran Çağdaş , Özçınar Evren , Çakıcı Mehmet , İnan Mustafa Bahadır , Akar Ahmet Ruchan
Published: October 2020

OBJECTIVES

Our goal was to compare the haemodynamic effects of different mechanical left ventricular (LV) unloading strategies and clinical outcomes in patients with refractory cardiogenic shock supported with venoarterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

A total of 448 patients supported with VA-ECMO for refractory cardiogenic shock between 1 March 2015 and 31 January 2020 were included and analysed in a single-centre, retrospective case–control study. Fifty-three patients (11.8%) on VA-ECMO required LV unloading. Percutaneous balloon atrial septostomy (PBAS), intra-aortic balloon pump (IABP) and transapical LV vent (TALVV) strategies were compared with regards to the composite rate of death, procedure-related complications and neurological complications. The secondary outcomes were reduced pulmonary capillary wedge pressure, pulmonary artery pressure, central venous pressure, left atrial diameter and resolution of pulmonary oedema on a chest X-ray within 48 h.

RESULTS

No death related to the LV unloading procedure was detected. Reduction in pulmonary capillary wedge pressure was highest with the TALVV technique (17.2 ± 2.1 mmHg; P < 0.001) and was higher in the PBAS than in the IABP group; the difference was significant (9.6 ± 2.5 and 3.9 ± 1.3, respectively; P = 0.001). Reduction in central venous pressure with TALVV was highest with the other procedures (7.4 ± 1.1 mmHg; P < 0.001). However, procedure-related complications were significantly higher with TALVV compared to the PBAS and IABP groups (50% vs 17.6% and 10%, respectively; P = 0.015). We observed no significant differences in mortality or neurological complications between the groups.

CONCLUSIONS

Our results suggest that TALVV was the most effective method for LV unloading compared with PBAS and IABP for VA-ECMO support but was associated with complications. Efficient LV unloading may not improve survival.
The impact of particulate matter air pollution (PM2.5) on atherosclerosis in modernizing China: a report from the CATHAY study
Authors: Woo K S , Chook P , Hu Y J , Lao X Q , Lin C Q , Lee PWA , Kwok CYT , Wei A N , Guo D S , Yin Y H , Lau KHA , Leung K S , Leung Y , Celermajer D S
Published: October 2020

Background

Air pollution has been associated with an increase in cardiovascular diseases incidence. To evaluate whether air pollution can accelerate atherogenic processes, we assessed the effects of air pollution on important surrogate markers of atherosclerosis [brachial flow-mediated dilation (FMD) and carotid intima-media thickness (IMT)].

Methods

A total of 1656 Han Chinese (mean age 46.0 + 11.2 years; male 47%) in Hong Kong, Macau, Pun Yu, Yu County and the 3-Gorges Territories (Yangtze River) were studied between 1996 and 2007 [Chinese Atherosclerosis in the Aged and Young Project (the CATHAY Study)]. Cardiovascular risk profiles were evaluated. Particulate matter with an aerodynamic diameter <2.5 µm (PM2.5) parameters were computed from satellite sensors. Brachial FMD and carotid IMT were measured by ultrasound.

Results

Health parameters [age, gender, body mass index, waist : hip ratio (WHR) and glucose)] were similar in lowest and highest PM2.5 exposure tertiles, systolic and diastolic blood pressures and triglycerides were higher (P < 0.001) and low-density cholesterol (LDL-C) was lower in the top PM2.5 tertile (P < 0.001). Brachial FMD [7.84 ± 1.77, 95% confidence interval (CI) 7.59–8.10%, vs 8.50 ± 2.52, 95% CI 8.23–8.77%, P < 0.0001) was significantly lower and carotid IMT (0.68 ± 0.13 mm, 95% CI 0.67–0.69 mm vs 0.63 mm ± 0.15 mm 95% CI 0.62–0.64 mm; P < 0.0001) was significantly thicker in the top PM2.5 tertile compared with the lowest tertile. On multiple regression, FMD was inversely related to PM2.5 (beta = 0.134, P = 0.015) independent of gender, age and blood pressure (model R2 = 0.156, F-value = 7.6, P < 0.0001). Carotid IMT was significantly correlated with PM2.5 exposure (beta = 0.381, P < 0.0001) independent of age, location, gender, WHR, blood pressure and LDL-C (model R2 = 0.408, F-value = 51.4, P-value <0.0001).

Conclusions

Air pollution is strongly associated with markers of early atherosclerosis, suggesting a potential target for preventive intervention.
On the Number of Quadratic Twists with a Rational Point of Almost Minimal Height
Authors: Petit Joachim
Published: October 2020

We investigate the number of curves having a rational point of almost minimal height in the family of quadratic twists of a given elliptic curve. This problem takes its origin in the work of Hooley, who asked this question in the setting of real quadratic fields. In particular, he showed an asymptotic estimate for the number of such fields with almost minimal fundamental unit. Our main result establishes the analogue asymptotic formula in the setting of quadratic twists of a fixed elliptic curve.
Using evidence-based infographics to increase parents’ understanding about antibiotic use and antibiotic resistance: a proof-of-concept study
Authors: Van Hecke Oliver , Lee Joseph J , Butler Chris C , Moore Michael , Tonkin-Crine Sarah
Published: October 2020

Background

Communities need to see antibiotic stewardship campaigns as relevant to enhance understanding of antibiotic use and influence health-seeking behaviour. Yet, campaigns have often not sought input from the public in their development.

Objectives

To co-produce evidenced-based infographics (EBIs) about antibiotics for common childhood infections and to evaluate their effectiveness at increasing parents’ understanding of antibiotic use.

Methods

A mixed-methods study with three phases. Phase 1 identified and summarized evidence of antibiotic use for three childhood infections (sore throat, acute cough and otitis media). In phase 2, we co-designed a series of prototype EBIs with parents and a graphic design team (focus groups). Thematic analysis was used to analyse data. Phase 3 assessed the effect of EBIs on parents’ understanding of antibiotic use for the three infections using a national online survey in the UK.

Results

We iteratively co-produced 10 prototype EBIs. Parents found the evidence displayed in the EBIs novel and relevant to their families. Parents did not favour EBIs that were too medically focused. Parents preferred one health message per EBI. We included eight EBIs in a national survey of parents (n = 998). EBIs improved knowledge by more than a third across the board (34%, IQR 20%–46%, P < 0.001). Respondents confirmed that EBIs were novel and potentially useful, corroborating our focus groups findings.

Conclusions

Co-designed EBIs have the potential to succinctly change parents’ perceptions about antibiotics for acute respiratory tract infections in children. Further research should test EBIs in real-world settings to assess their reach as a potential public-facing intervention.