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Late Ordovician Mass Extinction: Earth, fire and ice

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National Science Review 2024年第1期11卷 51-65页

作者： david A.T.harper Palaeoecosystems Group Department of Earth SciencesDurham University

The Late Ordovician Mass Extinction was the earliest of the ‘big’ five extinction events and the earliest to affect the trajectory of metazoan life. Two phases have been identified near the start of the hirnantian period and in the middle. it was a massive taxonomic extinction, a weak phylogenetic extinction and a relatively benign ecological extinction. A rapid cooling, triggering a major ice age that reduced the temperature of surface waters, prompted a drop in sea level of some 100 m and introduced toxic bottom waters onto the shelves. These symptoms of more fundamental planetary processes have been associated with a range of factors with an underlying driver identified as volcanicity. Volcanic eruptions, and other products, may have extended back in time to at least the Sandbian and early Katian, suggesting the extinctions were more protracted and influential than hitherto documented.

关键词： Ordovician LOME paleoecology palaeobiogeography biotas

One-dimensional monotone nonautonomous dynamical systems

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Science China Mathematics 2024年第2期67卷 281-314页

作者： david Cheban Faculty of Mathematics and Computer Science Laboratory of Fundamental and Applied MathematicsMoldova State UniversityChisinau 2009Moldova

This work is devoted to the study of the dynamics of one-dimensional monotone nonautonomous(cocycle) dynamical systems. A description of the structures of their invariant sets, omega limit sets,Bohr/Levitan almost periodic and almost automorphic motions, global attractors, and pinched and minimalsets is given. An application of our general results is given to scalar differential and difference equations.

关键词： one-dimensional dynamics pinched and minimal sets global attractors monotone nonautonomous cocycle almost periodic solutions scalar differential/difference equations

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Kerogen Kinetic Distributions and Simulations Provide insights into Petroleum Transformation Fraction (TF) Profiles of Organic-Rich Shales

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Journal of Earth Science 2024年第3期35卷 747-757页

作者： david A.Wood DWA Energy Limited Lincoln LN59JPUnited Kingdom

Two hundred and fifty single first-order Arrhenius reactions are simulated to generate S2 pyrograms at three heating rates 25,15,and 5°C·*** activation energy(E)and pre-exponential factor(A)of the reactions simulated follow a long-established trend of those variable values displayed by shales and *** characteristics of the transformation fraction(TF)profiles(product generation window temperatures)of the simulated single reactions are compared to the TF profiles of recorded shale pyrograms generated by multiple reactions with different E-A values lying near the defined E-A *** similarities and differences are observed between the TF profile values of the two *** similarities support the spread of E-A values involved in shale pyrogram best *** differences are most likely explained by the complexity of the multiple kerogen first-order and second-order reactions contributing to the recorded shale pyrograms versus the simplicity and crispness of the single first-order reactions *** results also justify the validity of using the previously described“variable E-A pyrogram-fitting method”of multi-heating-rate shale pyrograms enabling optimizers to choose multiple reactions from an unlimited range of E-A *** contrast,further doubt is cast on the validity of the constant-A pyrogram-fitting method used by the Easy%Ro technique,in that a distribution of reactions with a single A value is unlikely to represent the complex variety of kerogen macerals observed in shale *** profiles generated by the variable E-A pyrogram-fitting method lie close to the established E-A trend and are likely to provide more realistic TF generation window temperatures than TF profiles generated by the constant-A pyrogram-fitting method.

关键词： transformation fraction profiles simulated S2 pyrograms multiple heating rates kerogen/shale kinetics S2 pyrogram fitting techniques kerogen petroleum research.

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Analysis of ancient mass extinction recoveries in marine environments: generating strategies for managing outcomes of the current mass extinction

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National Science Review 2024年第1期11卷 8-10页

作者： david J.Bottjer Department of Earth Sciences University of Southern California

The defining feature of a mass extinction and its associated recovery is the global amount of extinction that occurred[1]. however, there is finer-scale detail to the story, as seen in the ongoing modern mass extinction(the sixth mass extinction), which exhibits variable effects among marine ecosystems and environments, and hence geographic areas [1].

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Modeling West Nile Virus transmission in birds and humans:Advantages of using a cellular automata approach

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infectious Disease Modelling 2024年第1期9卷 278-297页

作者： Baki Cissé david R.Lapen KChalvet-Monfray Nicholas h.Ogden Antoinette Ludwig Public health Sciences Division National Microbiology LaboratoryPublic Health Agency of CanadaSt-HyacintheCanada Groupe de Recherche enÉpidémiologie des Zoonoses et SantéPublique(GREZOSP) Facultéde Médecine VétérinaireUniversitéde MontréalSaint-HyacintheQuébecCanada Ottawa Research and Development Centre Science and Technology BranchAgriculture and Agri-Food CanadaOttawaK1A 0C6Canada Universitéde Lyon INRAEVetAgro SupUMR EPIAMarcy l’EtoileFrance UniversitéClermont Auvergne INRAEVetAgro SupUMR EPIASaint-Genès-ChampanelleFrance

in Canada,the periodic circulation of West Nile Virus(WNV)is difficult to predict and,beyond climatic factors,appears to be related to the migratory movements of infected birds from the southern United *** hypothesis has not yet been explored in a spatially distributed *** main objective of this work was to develop a spatially explicit dynamic model for the transmission of WNV in Canada,that allows us to explore non-climate related hypotheses associated with WNV transmission.A Cellular Automata(CA)approach for multiple hosts(birds and humans)is used for a test region in eastern Ontario,*** tool is designed to explore the role of host and vector spatial heterogeneity,host migration,and vector feeding *** developed a spatialized compartmental SEiRDS-SEi model for WNV transmission with a study region divided into 4 rectangular *** used 2010–2021 bird data from the eBird project and 2010–2019 mosquito data collected by Ontario Public health to mimic bird and mosquito seasonal *** considered heterogeneous bird densities(high and low suitability areas)and homogeneous mosquito and human *** high suitability areas for birds,we identified 5 entry points for WNV-infected *** compared our simulations with pools of WNV-infected field collected *** and sensitivity analyses were performed using MATLAB *** results showed good correspondence between simulated and observed epidemics,supporting the validity of our model assumptions and *** analysis showed that a 5%increase or decrease in each parameter of our model except for the biting rate of bird by mosquito(c^(B,M)and mosquito natural mortality rate(d^(M)),had a very limited effect on the total number of cases(newly infected birds and humans),prevalence peak,or date of *** demonstrate the utility of the CA approach for studying WNV transmission in a heterogeneous landscape with multiple hosts.

关键词： Cellular automata Mosquito-borne diseases SEiRDS-SEi modeling West Nile Virus

Current state-of-the-art review of footwear–ground friction

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Friction 2024年第10期12卷 2188-2204页

作者： david REBENDA Tomáš SÁhA Footwear Research Centre University InstituteTomas Bata University in ZlinZlin 76001Czech Republic Faculty of Mechanical Engineering Brno University of TechnologyBron 61600Czech Republic

The most important role of footwear is to ensure safe,functional walking,and foot *** the proper functionality of not only the work shoes,the anti-slip behavior of the shoe under various conditions and environments plays an important role in the prevention of slips,trips,falls,and consequent *** article is intended to review the current understanding of the frictional mechanisms between shoe outsoles and various counterfaces that impact the evaluation of outsole *** research focuses on the mechanisms driving outsole friction on different ground surfaces or the definition and description of parameters that influence outsole ***,the review discusses the effect of various surface contaminants on footwear ***,challenges and outlooks in the field of footwear outsoles are briefly mentioned.

关键词： shoe outsole composite slipperiness coefficient of friction(COF) adhesion safe walk

Thermal conductivity suppression in uranium-doped thorium dioxide due to phonon-spin interactions

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Journal of Materiomics 2024年第3期10卷 709-715页

作者： Zilong hua Saqeeb Adnan Amey R.Khanolkar Karl Rickert david B.Turner Timothy A.Prusnick J.Matthew Mann david h.hurley Marat Khafizov Cody A.Dennett Materials Science and Engineering Department Idaho National LaboratoryIdaho FallsID83415USA Department of Mechanical and Aerospace Engineering The Ohio State UniversityColumbusOH43210USA KBR DaytonOH45431USA Azimuth Corporation FairbornOH45324USA Air Force Research Laboratory Wright-Patterson AFBOH45433USA Department of Nuclear Science and Engineering Massachusetts Institute of TechnologyCambridgeMA02139USA

in this work,impact of low level of uranium(U)atom substitution on thermal conductivity of thorium dioxide(ThO_(2))is ***_(2)is an electronic insulator with a wide optical band-gap and no unpaired electrons whose thermal transport is governed by phonons.U-substitution introduces unpaired f-electrons resulting in paramagnetic behavior of UeThO_(2)at room temperature,which significantly suppresses its thermal conductivity.A single crystal of UeThO_(2)with graded composition of U is grown using a hydrothermal synthesis method,and thermal conductivity measurements are performed in re-gions with uniform composition of U at levels of 0%,6%,9%and 16%.Measured thermal conductivity profiles over 77e300 K temperature range are analyzed using an analytical expression for phonon-mediated thermal transport based on Klemens-Callaway *** dependent thermal con-ductivity is found to deviate significantly from the Rayleigh scattering trend expected for a simple substitutional point defect with a small perturbation to mass and interatomic *** the resonant scattering term,observed large suppression of thermal conductivity at low temperatures can be closely ***,the extracted phonon-spin coupling constants imply a nonlinear relation of phonon-spin interaction intensity with respect to U doping *** study reveals how phonon-spin scattering contributed by unpaired f-electrons in U atoms influences thermal transport in the UeThO_(2)system.

关键词： Phonon-spin interactions Thermal conductivity UdThO_(2)system

Amyloid-beta and tau protein beyond Alzheimer's disease

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Neural Regeneration Research 2024年第6期19卷 1262-1276页

作者： Morteza Abyadeh Vivek Gupta Joao A.Paulo Arezoo Gohari Mahmoudabad Sina Shadfar Shahab Mirshahvaladi Veer Gupta Christine T.O.Nguyen david i.Finkelstein Yuyi You Paul A.haynes Ghasem h.Salekdeh Stuart L.Graham Mehdi Mirzaei ProGene Technologies Pty Ltd. SydneyNSWAustralia Department of Clinical Medicine Faculty of MedicineHealth and Human SciencesMacquarie Medical SchoolMacquarie UniversityMacquarie ParkNorth RydeSydneyNSWAustralia Department of Cell Biology Harvard Medical SchoolBostonMAUSA School of Medicine Deakin UniversityGeelongVICAustralia Department of Optometry and Vision Sciences School of Health SciencesFaculty of Medicine Dentistry and Health SciencesUniversity of MelbourneParkvilleVICAustralia The Florey institute of Neuroscience and Mental health The University of MelbourneParkvilleVICAustralia School of Natural Sciences Macquarie UniversityMacquarie ParkNSWAustralia

The aggregation of amyloid-beta peptide and tau protein dysregulation are implicated to play key roles in Alzheimer's disease pathogenesis and are considered the main pathological hallmarks of this devastating ***,these two proteins are produced and expressed within the normal human ***,under pathological conditions,abnormal expression,posttranslational modifications,conformational changes,and truncation can make these proteins prone to aggregation,triggering specific disease-related *** studies have indicated associations between aberrant behavior of amyloid-beta and tau proteins and various neurological diseases,such as Alzheimer's disease,Parkinson's disease,and amyotrophic lateral sclerosis,as well as retinal neurodegenerative diseases like Glaucoma and age-related macular ***,these proteins have been linked to cardiovascular disease,cancer,traumatic brain injury,and diabetes,which are all leading causes of morbidity and *** this comprehensive review,we provide an overview of the connections between amyloid-beta and tau proteins and a spectrum of disorders.

关键词： amyloid-beta cancer cardiovascular diseases diabetes neurodegeneration Tau traumatic brain injury

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Gastroesophageal reflux following peroral endoscopic myotomy for achalasia:Bumps in the road to success

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World Journal of Gastroenterology 2024年第29期30卷 3461-3464页

作者： david itskoviz Stephen david howard Malnick Kaplan Medical Center Institute of Gastroenterology and HepatologyHebrew University Medical School of JerusalemRehovot 76100Israel Kaplan Medical Center Department of Internal Medicine CHebrew University Medical School of JerusalemRehovot 76100Israel

Achalasia can significantly impair the quality of *** clinical presentation typically includes dysphagia to both solids and liquids,chest pain,and *** can be delayed in patients with atypical presentations,and they might receive a wrong diagnosis,such as gastroesophageal reflux disease(GERD),owing to overlapping symptoms of both *** the cause of achalasia is poorly understood,its impact on the motility of the esophagus and gastroesophageal junction is well *** treatment modalities have been utilized,with the most common being surgical heller myotomy with concomitant fundoplication and pneumatic balloon ***,peroral endoscopic myotomy(POEM)has gained popularity as an effective treatment for achalasia,despite a relatively high incidence of GERD occurring after treatment compared to other *** magnitude of post-POEM GERD depends on its definition and is influenced by patient and procedure-related *** longterm sequelae of post-POEM GERD are yet to be determined,but it appears to have a benign course and is usually manageable with clinically available *** risk factors for post-POEM GERD and modifying the POEM procedure in selected patients may improve the overall success of this technique.

关键词： Achalasia Per-oral endoscopic myotomy Gastroesophageal reflux Pneumatic dilatation heller myotomy Proton pump inhibitor Acidic fermentation