检索结果-南通市图书馆

The great catastrophe: causes of the permo-Triassic marine mass extinction

National Science Review 2024年第1期11卷 37-50页

作者： paul b.Wignall David p.G.bond School of Earth & Environment University of Leeds School of Environmental Sciences University of Hull

The marine losses during the permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(pid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A Hybrid Machine Learning Approach for Improvised QoE in Video Services over 5G Wireless Networks

引用

Computers, Materials & Continua 2024年第3期78卷 3195-3213页

作者： K.b.Ajeyprasaath p.Vetrivelan School of Electronics Engineering Vellore Institute of TechnologyChennaiTamil Nadu600127India

Video streaming applications have grown considerably in recent *** a result,this becomes one of the most significant contributors to global internet *** to recent studies,the telecommunications industry loses millions of dollars due to poor video Quality of Experience(QoE)for *** the standard proposals for standardizing the quality of video streaming over internet service providers(ISps)is the Mean Opinion Score(MOS).However,the accurate finding of QoE by MOS is subjective and laborious,and it varies depending on the user.A fully automated data analytics framework is required to reduce the inter-operator variability characteristic in QoE *** work addresses this concern by suggesting a novel hybrid XGbStackQoE analytical model using a two-level layering *** one combines multiple Machine Learning(ML)models via a layer one Hybrid *** ML models at level one are trained using the entire training data *** level two Hybrid XGbStackQoE-Model is fitted using the outputs(meta-features)of the layer one ML *** proposed model outperformed the conventional models,with an accuracy improvement of 4 to 5 percent,which is still higher than the current traditional *** proposed framework could significantly improve video QoE accuracy.

关键词： Hybrid XGbStackQoE-model machine learning MOS performance metrics QoE 5G video services

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

biocompatible biphasic Iontronics Enable Neuron-Like Ionic Signal Transmission

引用

Research 2024年第3期2024卷 795-796页

作者： Xiaoyi Wang Aleksandar p.Ivanov Joshua b.Edel Department of Chemistry Imperial College LondonMolecular Sciences Research HubLondon W12 OBZUK

biocompatible connections between external artificial devices and living organisms show promise for future neuroprosthetics and *** study in Science by Zhao and colleagues introduces a cascade-heterogated biphasic gel(HbG)iontronic device,which facilitates electronic-to-multi-ionic signal transduction for abiotic–biotic *** by neuron signaling,the HbG device demonstrated its biocompatibility by regulating neural activity in biological tissue,paving the way for wearable and implantable devices,including brain–computer interfaces.

关键词： asi Signal Neuron

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Efficacy evaluation of standardized Rheum rhaponticum root extract(ERr 731®)on symptoms of menopause:A systematic review and meta-analysis study

引用

Journal of biomedical Research 2024年第3期38卷 278-286页

作者： Vishal p.Dubey Varun p.Sureja Dharmeshkumar b.Kheni Department of Scientific and Medical Affairs Sundyota Numandis Probioceuticals Pvt.Ltd.AhmedabadGujarat 380015India

Menopause is characterized by various physical,mental and emotional *** 731®is a standardized extract from Rheum rhaponticum root and has been clinically studied for its role in reducing menopausal *** current systematic review and meta-analysis aimed to evaluate the efficacy of ERr 731®supplementation in alleviating the severity of menopausal *** this review,we searched across three online databases up to March 2023,evaluated the quality of the included studies by the physiotherapy Evidence Database scale,and assessed the risk of bias by the Cochrane Risk of bias *** then performed a metaanalysis using RevMan software to estimate the pooled mean difference(MD).The study protocol was registered in the prospective Register of Systematic Reviews(CRD42023416808).After screening and evaluation,we included four high-quality studies(a total of 390 participants;the ERr 731®group:193 participants;the control group:197 participants)in the *** results showed that ERr 731®supplementation significantly reduced the Menopause Rating Scale score(MD:–15.12;ppared with control *** analysis revealed no effect of individual studies on the overall pooled estimate or overall observed *** current review provides evidence that ERr 731®supplementation is effective in reducing menopause *** bias and high heterogeneity in the results warrant further clinical studies.

关键词： menopause Rheum rhaponticum hot flashes systematic review

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

protein glycation:a wolf in sweet sheep’s clothing behind neurodegeneration

引用

Neural Regeneration Research 2024年第5期19卷 975-976页

作者： Ana b.Uceda Francisco Leal-pérez Miquel Adrover Institut Universitari d’Investigacióen Ciències de la Salut(IUNICS) Institut d’InvestigacióSanitària Illes balears(IdISba) Departament de Química Universitat de les Illes BalearsCtraPalma de MallorcaSpain

At the beginning of the 16th century,paracelsus coined the maxim:“the dose makes the poison”.This principle can be applied to all living organisms,including organs and *** brain and its glial and neuronal cells are ... 详细信息

关键词： organs sheep sweet

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Simulation and experimentation of propeller-Savonius turbine tested underwater surface

引用

Clean Energy 2024年第3期8卷 20-33页

作者： Sri Wuryanti Teguh Sasono bambang p.Manunggal Wahyu b.Mursanto Sugianto Department of Energy Conversion Engineering Politeknik Negeri BandungIndonesia Department of Mechanical Engineering Politeknik Negeri BandungIndonesia

Indonesia’s vast maritime territory offers a unique opportunity for harnessing the potential Energy of seawater *** study explores the effectiveness of a combined Savonius and propeller-type turbine *** Savonius turbine,known for its efficiency in capturing ocean currents due to its large sweep area,is combined with a propeller-type turbine to enhance rotational speed and power generation.A novel approach is employed to induce turbulence and optimize energy extraction,first channeling water through the propeller turbine and then into the Savonius turbine.A comprehensive investigation is conducted through simulations and experimental tests within a controlled tunnel *** study explores the performance of two-bladed and three-bladed propeller-Savonius configurations at varying inlet water velocities(0.1,0.3,0.6 and 1.0 m/s).The simulation incorporates a turbulence model with 5%intensity and a hydraulic diameter of 0.216 *** indicate that the proposed configuration achieves a maximum power output of 2.0293 W with an impressive efficiency of 63.339%in ***,experimental testing yields a peak efficiency of 61.335%and turbine power of 0.3951 *** findings demonstrate the feasibility of the combined turbine system and highlight the importance of turbulence in optimizing energy extraction from seawater *** research contributes valuable insights into the design and performance of hybrid turbines for harnessing oceanic Energy,emphasizing the potential for sustainable power generation in maritime *** methodology and results presented herein offer a foundation for further exploration and refinement of seawater current energy conversion technologies.

关键词： hydro-turbine propeller-Savonius renewable energy water

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ab initio density response and local field factor of warm dense hydrogen

引用

Matter and Radiation at Extremes 2024年第5期9卷 48-67页

作者： Tobias Dornheim Sebastian Schwalbe panagiotis Tolias Maximilian p.böhme Zhandos A.Moldabekov Jan Vorberger Center for Advanced Systems Understanding(CASUS) D-02826 GörlitzGermany Helmholtz-Zentrum Dresden-Rossendorf(HZDR) D-01328 DresdenGermany Space and plasma physics Royal Institute of Technology(KTH)Stockholm SE-10044Sweden Technische Universität Dresden D-01062 DresdenGermany

We present quasi-exact ab initio path integral Monte Carlo(pIMC)results for the partial static density responses and local field factors of hydrogen in the warm dense matter regime,from solid density conditions to the strongly compressed *** full dynamic treatment of electrons and protons on the same footing allows us to rigorously quantify both electronic and ionic exchange–correlation effects in the system,and to compare the results with those of earlier incomplete models such as the archetypal uniform electron gas or electrons in a fixed ion snapshot potential that do not take into account the interplay between the two *** full electronic density response is highly sensitive to electronic localization around the ions,and our results constitute unambiguous predictions for upcoming X-ray Thomson scattering experiments with hydrogen jets and fusion *** pIMC results are made freely available and can be used directly for a gamut of applications,including inertial confinement fusion calculations and the modeling of dense astrophysical ***,they constitute invaluable benchmark data for approximate but computationally less demanding approaches such as density functional theory or pIMC within the fixed-node approximation.

关键词： local incomplete rigorous

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Temperature and structure measurements of heavy-ion-heated diamond using in situ X-ray diagnostics

引用

Matter and Radiation at Extremes 2024年第4期9卷 80-89页

作者： J.Lutgert p.Hesselbach M.Schorner V.bagnoud R.belikov p.Drechsel b.Heuser O.SHumphries p.Katrik b.Lindqvist C.Qu R.Redmer D.Riley G.Schaumann S.Schumacher A.Tauschwitz D.Varentsov K.Weyrich X.Yu b.Zielbauer Zs.Major p.Neumayer D.Kraus Institut fur physik Universitat RostockAlbert-Einstein-Str.2318059 RostockGermany GSI Helmholtzzentrum fur Schwerionenforschung Planckstr.164291 DarmstadtGermany Institut für Angewandte physik Goethe-Universität Frankfurt am MainMax-von-Laue-Str.160438 Frankfurt am MainGermany Institut fur Geowissenschaften Goethe-Universitat Frankfurt am MainAltenhoferallee 160438 Frankfurt am MainGermany Helmholtz-Zentrum Dresden-Rossendorf Bautzner Landstr.40001328 DresdenGermany European XFEL GmbH Holzkoppel 422869 SchenefeldGermany Centre for plasma physics School of Mathematics and PhysicsQueen’s University BelfastUniversity RoadBelfast BT71NNUnited Kingdom Institut für Kernphysik Technische Universität DarmstadtSchlossgartenstr.964289 DarmstadtGermany State Key Laboratory of Nuclear physics and Technology Institute of Heavy Ion PhysicsPeking UniversityBeijing 100871China Helmholtz Institut Jena Frobelstieg 307743 JenaGermany

We present in situ measurements of spectrally resolved X-ray scattering and X-ray diffraction from monocrystalline diamond samples heatedwith an intense pulse of heavy *** this way,we determine the samples’heating dynamics and their microscopic and macroscopic structuralintegrity over a timespan of several *** the ratio of elastic to inelastic scattering with state-of-the-art density functionaltheory molecular dynamics simulations allows the inference of average temperatures around 1300 K,in agreement with predictions fromstopping power *** simultaneous diffraction measurements show no hints of any volumetric graphitization of the material,butdo indicate the onset of fracture in the diamond *** experiments pave the way for future studies at the Facility for Antiproton andIon Research,where a substantially increased intensity of the heavy ion beam will be available.

关键词： heated intense structure

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asiaticoside ameliorates type 2 diabetes mellitus in rats by modulating carbohydrate metabolism and regulating insulin signaling

引用

Asian pacific Journal of Tropical biomedicine 2024年第9期14卷 401-409页

作者： b.prathap V.Satyanarayanan K.Duraipandian p.Subashree Department of pharmacology Karpaga Vinayaga Institute of Medical Sciences and Research CenterMaduranthakam 603308Tamil NaduIndia Department of pharmacology SRM Medical College Hospital and Research CenterKattankulathur 603211Tamil NaduIndia Department of Anatomy Karpaga Vinayaga Institute of Medical Sciences and Research CenterMaduranthakam 603308Tamil NaduIndia Department of Ophthalmology Karpaga Vinayaga Institute of Medical Sciences and Research CenterMaduranthakam 603308Tamil NaduIndia

Objective:To evaluate the effect of asiaticoside on streptozotocin(STZ)and nicotinamide(NAD)-induced carbohydrate metabolism abnormalities and deregulated insulin signaling pathways in ***:Asiaticoside(50 and 100 mg/kg body weight)was administered to STZ-NAD-induced diabetic rats for 45 days,and its effects on hyperglycaemic,carbohydrate metabolic,and insulin signaling pathway markers were ***:Asiaticoside increased insulin production,lowered blood glucose levels,and enhanced glycolysis by improving hexokinase activity and suppressing glucose-6-phosphatase and fructose-1,6-bisphosphatase *** in glycogen metabolism were mitigated by increasing glycogen synthase activity and gluconeogenesis was decreased by decreasing glycogen phosphorylase ***,asiaticoside upregulated the mRNA expressions of IRS-1,IRS-2,and GLUT4 in STZ-NAD-induced diabetic rats and restored the beta cell morphology to ***:Asiaticoside has the potential to ameliorate type 2 diabetes by improving glycolysis,gluconeogenesis,and insulin signaling pathways.

关键词： Asiaticoside Type 2 diabetes mellitus Metabolic disorders Carbohydrate metabolism Insulin signaling

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ferroelectricity Induced by Oxygen Vacancies in Rhombohedral ZrO_(2) Thin Films

引用

Energy & Environmental Materials 2024年第1期7卷 229-237页

作者： Veniero Lenzi José p.b.Silva břetislav Šmíd Vladimir Matoín Cosmin M.Istrate Corneliu Ghica Judith L.MacManus-Driscoll Luís Marques physics Center of Minho and porto Universities(CF-UM-Up) University of MinhoCampus de Gualtar 4710-057Braga Portugal Laboratory of physics for Materials and Emergent Technologies LapMETUniversity of Minho4710-057Braga Portugal Department of Surface and plasma Science Faculty of Mathematics and PhysicsCharles UniversityV Holešovičkách 218000Prague 8 Czech Republic National Institute of Materials physics 105 bis Atomistilor 077125Magurele Romania Department of Materials Science and Metallurgy 27 Charles Babbage Rd.Cambridge CB3 OFSUK

Rhombohedral phase Hf_(x)Zr_(1.x)O_(2)(HZO,x from 0 to 1)films are promising for achieving robust ferroelectric polarization without the need for an initial wake-up pre-cycling,as is normally the case for the more commonly studied orthorhombic ***,a large spontaneous polarization observed in rhombohedral films is not fully understood,and there are also large discrepancies between experimental and theoretical *** this work,in rhombohedral ZrO_(2)thin films,we show that oxygen vacancies are not only a key factor for stabilizing the phase,but they are also a source of ferroelectric polarization in the *** is shown experimentally through the investigation of the structural properties,chemical composition and the ferroelectric properties of the films before and after an annealing at moderate temperature(400℃)in an oxygen environment to reduce the V_(o)concentration *** experimental work is supported by density functional theory(DFT)calculations which show that the rhombohedral phase is the most stable one in highly oxygen defective ZrO_(2)*** DFT calculations also show that V_(o)contribute to the ferroelectric *** findings reveal the importance of V_(o)for stabilizing rhombohedral ZrO_(2)thin films with superior ferroelectric properties.

关键词： charged defects ferroelectric polarization rhombohedral phase stability zirconia

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：