检索结果-南通市图书馆

Well-Posedness of Stochastic Continuity Equations on Riemannian Manifolds

在线全文

学校读者我要写书评

暂无评论

Chinese Annals of Mathematics,Series B 2024年第1期45卷 81-122页

作者： Luca GALIMBERTI kenneth h.KARLSEN Department of Mathematical Sciences NTNU Norwegian University of Science and TechnologyN-7491 TrondheimNorway Department of mathematics University of OsloP.O.Box 1053BlindernN-0316 OsloNorway

The authors analyze continuity equations with Stratonovich stochasticity,■ρ+divh[ρo(u(t,x)+∑_(i=1)^(N)a_(i)(x)w_(i)(t))]=0defined on a smooth closed Riemannian manifold M with metric *** velocity field u is perturbed by Gaussian noise terms Wi(t),:WN(t)driven by smooth spatially dependent vector fields a1(x),...,aN(x)on *** velocity u belongs to L_(t)^(1)W_(x)^(1,2)with divh u bounded in Lf,for p>d+2,where d is the dimension of M(they do not assume div_(h) u∈L_(t,x)^(∞)).For carefully chosen noise vector fields ai(and the number N of them),they show that the initial-value problem is well-posed in the class of weak L^(2) solutions,although the problem can be ill-posed in the deterministic case because of concentration *** proof of this“regularization by noise”result is based on a L^(2) estimate,which is obtained by a duality method,and a weak compactness argument.

关键词： Stochastic continuity equation Riemannian manifold hyperbolic equa-tion Non-smooth velocity field Weak solution Existence Uniqueness

Biophotoelectrochemistry:An emerging frontier for channeling photoelectric effect into darkness zone of soils and sediments

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2024年第1期34卷 5-8页

作者： Jie YE Shungui ZhOU kenneth h.NEALSON Christopher RENSING Fujian Provincial Key Laboratory of Soil Environmental health and Regulation College of Resources and EnvironmentFujian Agriculture and Forestry UniversityFuzhou 350002China Department of Earth Science University of Southern CaliforniaLos Angeles CA 90007USA

Solar energy captured by photosynthetic plants in the photic zone is recognized as the main driver for the formation of organic matter utilized by soil communities. however, the contribution of organic transformation to the linkage of solar energy and microbial metabolism of soils is reduced when the vadose zone is saturated. In contrast to the conventional biophotoelectrochemistry via photosynthesis with phytoplankton during the periodic saturation of soils, recent studies suggest that non-phototrophic microorganisms in soils and sediments are able to conduct light-dependent metabolism to sustain their functionality with photosensitizers under illumination. These interactions and processes utilize long-distance electron transfer networks to interconnect diverse electron transfer chains that channel photoexcited electrons into the opaque zone for soil communities. Such an emerging process not only allows for a better understanding of biogeochemical processes such as soil carbon sequestration and mitigation, but also shows great potential for environmental treatment such as the bioremediation of contaminated soils. Therefore, we suggest that biophotoelectrochemistry via photoelectric effect can have significant, heretofore unappreciated, theoretical and practical values.

关键词： soils soil metabolism

New Opportunities for Neutrons in Environmental and Biological Sciences

在线全文

学校读者我要写书评

暂无评论

Frontiers of Environmental Science & Engineering 2024年第7期18卷 179-186页

作者： Alexander Johs Shuo Qian Leighton Coates Brian h.Davison James G.Elkins Xin Gu Jennifer Morrell-Falvey hugh O'Neill Jeffrey M.Warren Eric M.Pierce kenneth herwig Oak Ridge National Laboratory Oak RidgeTN37831USA

The use of neutron methods in environmental and biological sciences is rapidly emerging and accelerating with the development of new instruments at neutron user *** article,based on a workshop held at Oak Ridge National Laboratory(ORNL),offers insights into the application of neutron techniques in environmental and biological *** highlight recent advances and identify key challenges and potential future research *** include soil and rhizosphere processes,root water dynamics,plant-microbe interactions,structure and dynamics of biological systems,applications in synthetic biology and enzyme engineering,next-generation bioproducts,biomaterials and bioenergy,nanoscale structure,and fluid dynamics of porous materials in *** provide an outlook on emerging opportunities with an emphasis on new capabilities that will be enabled at the Spallation Neutron Source Second Target Station currently under design at *** mission of scientific neutron user facilities worldwide is to enable science using state-of-the-art neutron *** aim to encourage researchers in the environmental and biological research community to explore the unique capability afforded by neutrons at these facilities.

关键词： Neutrons Environment Biology Neutron imaging Neutron scattering Second Target Station(STS)

Three-stage pyrolysis–steam reforming–water gas shift processing of household,commercial and industrial waste plastics for hydrogen production

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Waste Disposal and Sustainable Energy 2024年第1期6卷 25-37页

作者： Rayed Alshareef Robert Sait-Stewart Mohamad A.Nahil Paul T.williams School of Chemical and Process Engineering University of LeedsLeedsLS29JTUK

Five common single plastics and nine different household,commercial and industrial waste plastics were processed using a three-stage(i)pyrolysis,(ii)catalytic steam reforming and(iii)water gas shift reaction system to produce *** of plastics produces a range of different hydrocarbon species which are subsequently catalytically steam reformed to produce h_(2)and CO and then undergo water gas shift reaction to produce further h_(2).The process mimics the commercial process for hydrogen production from natural *** of the single polyalkene plastics(high-density polyethylene(hDPE),low-density polyethylene(LDPE),and polypropylene(PP))produced similar h_(2)yields between 115 mmol and 120 mmol per gram *** though PS produced an aromatic product slate from the pyrolysis stage,further stages of reforming and water gas shift reaction produced a gas yield and composition similar to that of the polyalkene plastics(115 mmol h_(2)per gram plastic).PET gave significantly lower h_(2)yield(41 mmol per gram plastic)due to the formation of mainly CO,CO_(2)and organic acids from the pyrolysis stage which were not conducive to further reforming and water gas shift reaction.A mixture of the single plastics typical of that found in municipal solid waste produced a h_(2)yield of 102 mmol per gram *** the gas yields and composition from the single plastics enabled an estimation of the yields from a simulated waste plastic mixture and a‘real-world’waste plastic mixture to be *** different household,commercial and industrial waste plastic mixtures produced h_(2)yields between 70 mmol and 107 mmol per gram *** h_(2)yield and gas composition from the single waste plastics gave an indication of the type of plastics in the mixed waste plastic samples.

关键词： Waste plastic hydrogen Catalyst Pyrolysis reforming Water gas shift

Individual and geospatial factors associated with receipt of colorectal cancer screening:a state-wide mixed-level analysis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Family Medicine and Community health 2024年第S2期12卷 18-25页

作者： Jennifer E Bayly Mara A Schonberg Marcia C Castro kenneth J Mukamal Beth Israel Deaconess Medical Center BostonMassachusettsUSA harvard Medical School BostonMassachusettsUSA Department of Global health and Population Harvard T H Chan School of Public HealthBostonMassachusettsUSA

Background Colorectal cancer(CRC)is the second leading cause of cancer death in US adults but can be reduced by *** roles of individual and contextual factors,and especially physician supply,in attaining universal CRC screening remains *** We used data from adults 50-75 years old participating in the 2018 New York(NY)Behavioural Risk Factor Surveillance System linked to county-level covariates,including primary care physician(PCP)density and gastroenterologist(GI)*** were analysed in *** analyses included(1)ecological and geospatial analyses of county-level CRC screening prevalence and(2)individual-level Poisson regression models of receipt of screening,adjusted for socioeconomic and county-level contextual *** Mean prevalence of up-to-date CRC screening was 71%(95%CI 70%to 73%)across NY’s 62 ***-level CRC screening demonstrated significant spatial patterning(Global Moran’s I=0.14,p=0.04),consistent with the existence of county-level contextual *** both county-level and individual-level analyses,lack of health insurance was associated with lower likelihood of up-to-date screening(?−1.09(95%CI−2.00 to-0.19);adjusted prevalence ratio 0.68(95%CI 0.60 to 0.77)),even accounting for age,race/ethnicity and *** contrast,county-level densities of both PCPs and GIs were completely unassociated with screening at either the county or individual *** expected,other determinants at the individual level included education status and *** In this state-wide representative analysis,physician density was completely unassociated with CRC screening,although health insurance status remains strongly *** similar screening environments,broadened insurance coverage for CRC screening is likely to improve screening far more effectively than increased physician supply.

关键词： state screening county

Why ecosystem characteristics predicted from remotely sensed data are unbiased and biased at the same time-and how this affects applications

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2024年第1期11卷 24-31页

作者： Goran Ståhl Terje Gobakken Svetlana Saarela henrik J.Persson Magnus Ekstrom Sean P.healey Zhiqiang Yang Johan holmgren Eva Lindberg kenneth Nystrom Emanuele Papucci Patrik Ulvdal hans OleØrka Erik Næsset Zhengyang hou håkan Olsson Ronald E.McRoberts Department of Forest Resource Management Swedish University of Agricultural Sciences90183UmeåSweden Faculty of Environmental Sciences and Natural Resource Management Norwegian University of Life SciencesÅsNorway USDA Forest Service Rocky Mountain Research StationOgdenUTUSA The Key Laboratory for Silviculture and Conservation of Ministry of Education Beijing Forestry UniversityBeijing100083China Department of Forest Resources University of MinnesotaSt.PaulMNUSA

Remotely sensed data are frequently used for predicting and mapping ecosystem characteristics,and spatially explicit wall-to-wall information is sometimes proposed as the best possible source of information for ***,wall-to-wall information typically relies on model-based prediction,and several features of model-based prediction should be understood before extensively relying on this type of *** such feature is that model-based predictors can be considered both unbiased and biased at the same time,which has important implications in several areas of *** this discussion paper,we first describe the conventional model-unbiasedness paradigm that underpins most prediction techniques using remotely sensed(or other)auxiliary *** this point of view,model-based predictors are typically ***,we show that for specific domains,identified based on their true values,the same model-based predictors can be considered biased,and sometimes severely *** suggest distinguishing between conventional model-bias,defined in the statistical literature as the difference between the expected value of a predictor and the expected value of the quantity being predicted,and design-bias of model-based estimators,defined as the difference between the expected value of a model-based estimator and the true value of the quantity being *** show that model-based estimators(or predictors)are typically design-biased,and that there is a trend in the design-bias from overestimating small true values to underestimating large true ***,we give examples of applications where this is important to acknowledge and to potentially make adjustments to correct for the design-bias *** argue that relying entirely on conventional model-unbiasedness may lead to mistakes in several areas of application that use predictions from remotely sensed data.

关键词： Bias Model-based inference Design-based inference

Unequal Distribution of Innovation Efforts for Neglected Tropical Diseases: The Role of Funding Evaluation Criteria

在线全文

学校读者我要写书评

暂无评论

health 2024年第5期16卷 490-520页

作者： Anne M. G. Neevel kenneth D. S. Fernald Linda h. M. van de Burgwal Athena Institute Faculty of Science Vrije Universiteit Amsterdam Amsterdam Netherlands

Background: International research and innovation efforts for neglected tropical diseases have increased in recent decades due to disparities in overall health research funding in relation to global burden of disease. however, within the field of neglected tropical diseases some seem far more neglected than others. In this research the aim is to investigate the distribution of resources and efforts, as well as the mechanisms that underpin funding allocation for neglected tropical diseases. Methodology: A systematic literature review was conducted to establish a comprehensive overview of known indicators for innovation efforts related to a wide range of neglected tropical diseases. Articles were selected based on a subjective evaluation of their relevance, the presence of original data, and the breadth of their scope. This was followed by thirteen in-depth open-ended interviews with representatives of private, public and philanthropic funding organizations, concerning evaluation criteria for funding research proposals. Results: The findings reveal a large difference in the extent to which the individual diseases are neglected with notable differences between absolute and relative efforts. Criteria used in the evaluation of research proposals relate to potential impact, the probability of success and strategic fit. Private organizations prioritize strategic fit and economic impact;philanthropic organizations prioritize short-term societal impact;and public generally prioritize the probability of success by accounting for follow-up funding and involvement of industry. Funding decisions of different types of organizations are highly interrelated. Conclusions: This study shows that the evaluation of funding proposals introduces and retains unequal funding distribution, reinforcing the relative neglect of diseases. Societal impact is the primary rationale for funding but application of it as a funding criterion is associated with significant challenges. Furthermore, curre

关键词： Neglected Tropical Diseases Funding Decision Evaluation Criteria health Research Funding Research Impact

Long-term impact of artificial intelligence on colorectal adenoma detection in high-risk colonoscopy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastrointestinal Endoscopy 2024年第6期16卷 335-342页

作者： kenneth W Chow Matthew T Bell Nicholas Cumpian Maryanne Amour Ryan h hsu Viktor E Eysselein Neetika Srivastava Michael W Fleischman Sofiya Reicher Department of Medicine Harbor-UCLA Medical CenterTorranceCA 90502United States Department of Bioengineering Jacobs School of EngineeringUniversity of CaliforniaSan DiegoLa JollaCA 92093United States Department of Gastroenterology Harbor-UCLA Medical CenterTorranceCA 90502United States

BACKGROUND Improved adenoma detection rate(ADR)has been demonstrated with artificial intelligence(AI)-assisted ***,data on the real-world appli-cation of AI and its effect on colorectal cancer(CRC)screening outcomes is *** To analyze the long-term impact of AI on a diverse at-risk patient population undergoing diagnostic colonoscopy for positive CRC screening tests or *** AI software(GI Genius,Medtronic)was implemented into the standard proced-ure protocol in November *** was collected on patient demographics,procedure indication,polyp size,location,and *** screening outcomes were evaluated before and at different intervals after AI introduction with one year of *** We evaluated 1008 colonoscopies(278 pre-AI,255 early post-AI,285 established post-AI,and 190 late post-AI).The ADR was 38.1%pre-AI,42.0%early post-AI(P=0.77),40.0%established post-AI(P=0.44),and 39.5%late post-AI(P=0.77).There were no significant differences in polyp detection rate(PDR,baseline 59.7%),advanced ADR(baseline 16.2%),and non-neoplastic PDR(baseline 30.0%)before and after AI *** In patients with an increased pre-test probability of having an abnormal colonoscopy,the current generation of AI did not yield enhanced CRC screening metrics over high-quality *** the potential of AI in colonoscopy is undisputed,current AI technology may not universally elevate screening metrics across all situations and patient *** studies that analyze different AI systems across various patient populations are needed to determine the most effective role of AI in optimizing CRC screening in clinical practice.

关键词： Artificial intelligence Colonoscopy Adenoma detection rate Screening Colorectal adenoma

Predicting the mode of flow in pneumatic conveying systems—A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2008年第5期6卷 289-300页

作者： Mark G.Jones kenneth C.williams Centre for Bulk Solids and Particulate Technologies School of EngineeringUniversity of NewcastleNewcastle 2308Australia

An initial prediction of the particulate mode of flow in pneumatic conveying systems is beneficial as this knowledge can provide clearer direction to the pneumatic conveying design process. There are three general categories of modes of flow, two dense flows： fluidised dense phase and plug flow, and dilute phase oniy. Detailed in this paper is a review of the commonly used and available techniques for predicting mode of flow. Two types of predictive charts were defined： basic particle parameter based （e.g. particle size and density） and air-particle parameter based （e.g. permeability and de-aeration）. The basic particle techniques were found to have strong and weak areas of predictive ability, on the basis of a comparison with data from materials with known mode of flow capability. It was found that there was only slight improvement in predictive ability when the particle density was replaced by loose-poured bulk density in the basic parameter techniques. The air-particle-parameter-based techniques also showed well-defined regions for mode of flow prediction though the data set used was smaller than that for the basic techniques. Also, it was found to be difficult to utilise de-aeration values from different researchers and subsequently, an air-particle-based technique was developed which does not require any de-aeration parameter in its assessment.

关键词： Pneumatic conveying Mode of flow Dense phase Permeability De-aeration