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Stochastic particle based models for suspended particle movement in surface flows

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International Journal of Sediment Research 2014年第2期29卷 195-207页

作者： christina W.TSAI Chuanjian MAN Jungsun OH Department of Civil Structural and Environmental EngineeringState University of New York at BuffaloBuffaloNY 14051USA Assoc.Prof. Department of Civil and Environmental Engineering National Taiwan University

Modeling of suspended sediment particle movement in surface water can be achieved by stochastic particle tracking model *** this paper,different mathematical forms of particle tracking models are introduced to describe particle movement under various flow conditions,i.e.,the stochastic diffusion process,stochastic jump process,and stochastic jump diffusion *** the stochastic diffusion process can be used to represent the stochastic movement of suspended particles in turbulent flows,the stochastic jump and the stochastic jump diffusion processes can be used to describe suspended particle movement in the occurrences of a sequence of extreme *** extreme flow herein is defined as a hydrologic flow event or a hydrodynamic flow phenomenon with a low probability of occurrence and a high impact on its ambient flow *** this paper,the suspended sediment particle is assumed to immediately follow the extreme flows in the jump process(*** time lag between the flow particle and the sediment particle in extreme flows is considered negligible).In the proposed particle tracking models,a random term mainly caused by fluid eddy motions is modeled as a Wiener process,while the random occurrences of a sequence of extreme flows can be modeled as a Poisson *** frequency of occurrence of the extreme flows in the proposed particle tracking model can be explicitly accounted for by the Poisson process when evaluating particle *** ensemble mean and variance of particle trajectory can be obtained from the proposed stochastic models via *** ensemble mean and variance of particle velocity are verified with available *** of the proposed stochastic particle tracking models for sediment transport modeling is also discussed.

关键词： Suspended sediment Particle tracking model Stochastic modeling Diffusion process Poisson jump process Jump diffusion process Extreme flows

Wetland Economic Valuation Approaches and Prospects in China

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Chinese Geographical Science 2016年第2期26卷 143-154页

作者： JIANG Bo christina P.WONG CUI Lijuan OUYANG Zhiyun State Key Laboratory of Urban and Regional Ecology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China Changjiang Water Resources Protection Institute Wuhan 430051 China School of Sustainability Arizona State University Tempe AZ 85287 US.A Institute of Wetland Research Chinese Academy of Forestry Beijing 100091China

Ecosystem services valuation seeks to increase the social relevance of ecosystem characteristics, the underlying biological mechanisms that support services, by making the contribution of ecosystems to human well-being explicit. Economic valuation can help management by clarifying the full range of benefits and costs of proposed management actions. In the past two decades, economic valuation of wetland ecosystem services has become one of the most significant scientific priorities for wetland protection. In this paper, we provide an overview of ecosystem services, and summarize the main interdisciplinary approaches to measure and value wetland ecosystem services. We identified four main methodological gaps preventing progress on wetland valuation of ecosystem services in China, which are: 1) confusion on terminology like intermediate and final ecosystem services, 2) lack of ecological production functions to link ecosystem characteristics to final ecosystem services, 3) static valuation making it difficult to evaluate the trade-offs and synergies among ecosystem services, and 4) lack of clear guidance on relating ecological compensation programs to conservation targets. Overcoming these gaps is important to inform wetland compensation mechanisms and conservation policies. We propose future research on wetland ecosystem services in China should be focused on: 1) defining final ecosystem services based on beneficiary preferences and underlying biophysical mechanisms, 2) establishing wetland monitoring programs at specific sites to collect data on final ecosystem service indicators and ecosystem characteristic metrics to create ecological production functions for economic valuation and rescaling techniques, and 3) incorporating wetland ecosystem service values into decision-making processes to inform wetland management.

关键词： ecosystem services wetlands economic valuation methodological gaps China

Determination of selected semi-volatile organic compounds in water using automated online solid-phase extraction with large-volume injection/gas chromatography/mass spectrometry

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Frontiers of Environmental Science & Engineering 2011年第3期5卷 417-425页

作者： Yongtao LI christina L.MCCARTY Ed J.GEORGE Drinking Water Quality Laboratory Underwriters Laboratories Inc.South BendIN 46617USA Chemical Analysis Bruker DaltonicsFremontCA 94538USA

A rapid,sensitive,and cost-effective analyticalmethod was developed for the analysis of selected semivolatileorganic compounds in *** method used anautomated online solid-phase extraction technique coupledwith programmed-temperature vaporization large-volumeinjection gas chromatography/mass *** samples were extracted by using a fully automatedmobile rack system based on x-y-z robotic techniquesusing syringes and disposable 96-well extraction *** method was validated for the analysis of 30 semivolatileanalytes in drinking water,groundwater,andsurface *** a sample volume of 10 mL,the linearcalibrations ranged from 0.01 or 0.05 to 2.5μg·L^(-1),and themethod detection limits were less than 0.1μg·L^(-1).For thereagent water samples fortified at 1.0μg·L^(-1)and2.0μg·L^(-1),the obtained mean absolute recoveries were70%-130%with relative standard deviations of less than20%for most *** the drinking water,groundwater,and surface water samples fortified at 1.0μg·L^(-1),theobtained mean absolute recoveries were 50%-130%withrelative standard deviations of less than 20%for *** new method demonstrated three advantages:1)no manipulation except the fortification of surrogatestandards prior to extraction;2)significant cost reductionassociated with sample collection,shipping,storage,andpreparation;and 3)reduced exposure to hazardous solventsand other *** a result,this new automatedmethod can be used as an effective approach for screeningand/or compliance monitoring of selected semi-volatileorganic compounds in water.

关键词： automated solid-phase extraction programmed-temperature vaporization large-volume injection gas chromatography/mass spectrometry semi-volatile organic compounds water analysis

Controversies in Hirschsprung surgery

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World Journal of Pediatric Surgery 2024年第3期7卷 161-172页

作者： Thomas O Xu Marc A Levitt christina Feng Division of Colorectal and Pelvic Reconstruction Children's National HospitalWashingtonDistrict of ColumbiaUSA

The treatment of Hirschsprung disease(HSCR)is surgical resection of aganglionic bowel and subsequent pull-through of ganglionated *** many advances since the initial description of the disease and its surgical management more than half a century ago,there remain considerable controversies regarding the history of the surgical technique,the optimal timing of the primary and multistage pull-through,the best treatment for patients with a delayed diagnosis of HSCR,and the management of post pull-through complications such as soiling due to sphincter incompetence,the presence of a transition zone,and the prevention of *** following review will explore each of these controversies.

关键词： prevention diagnosis treatment

Informal Caregiving and Disaster Risk Reduction:A Scoping Review

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International Journal of Disaster Risk Science 2021年第2期12卷 169-187页

作者： christina J.Pickering Maya Dancey Karen Paik Tracey O’Sullivan Interdisciplinary School of Health Sciences University of OttawaOttawa KIN 6N5Canada EnRiCH Research Lab University of OttawaOttawa KIN 6N5Canada Telfer School of Management University of OttawaOttawa KIN 6N5Canada

Informal caregivers are a population currently in the shadows of disaster risk reduction(DRR),and yet essential to the provision of healthcare *** scoping review explored the literature to understand issues related to informal caregiving and promising practices to support resilience for *** guidelines for scoping review as outlined by Tricco et al.(2016),relevant publications were identified from five major databases—Medline,Embase,PubMed,Web of Science,and *** studies referenced informal caregiving and disasters for a variety of population groups including children,people with disabilities or chronic illnesses,and older *** were excluded if they discussed formal caregiving services(for example,nursing),lacked relevance to disasters,or had insufficient discussion of informal ***,21 articles met the inclusion criteria and were fully *** themes were identified:(1)the need for education and training in DRR;(2)stressors around medication and supply issues;(3)factors affecting the decision-making process in a disaster;(4)barriers leading to disaster-related problems;and(5)factors promoting *** areas of strategic action and knowledge gaps are *** informal caregivers do not feel adequately prepared for *** the important role of informal caregivers in healthcare provision,preparedness strategies are essential to support community resilience for those requiring personal care *** understanding and mobilizing assets to support the resilience of informal caregivers,we also support the resilience of the greater healthcare system and the community,in disaster contexts.

关键词： Caregiving Disaster resilience Disaster risk reduction Healthcare Informal caregiving

Simulation of urban microclimate with uhiSolver:software validation using simplifed material data

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Ecological Processes 2021年第1期10卷 921-943页

作者： Florian Teichmann christina Maria Baumgartner Andras Horvath Markus Luisser Azra Korjenic Vienna University of Technology ViennaAustria. Rheologic GmbH ViennaAustria.

Background:Increasing urbanization as well as global warming requires an investigation of the infuence of diferent construction methods and ground surfaces on the urban heat island efect(UHI efect).The extent of the infuence of the urban structure,the building materials used and their surfaces on the UHI efect can be signifcantly reduced already in the planning phase using a designated OpenFOAM-based solver“uhiSolver”.Results:In the frst part of this research work,it is shown that inner building details and components can be neglected while still obtaining sufciently accurate *** this purpose,the building model was divided into two layers:a surface layer without mass,where the interaction with radiation takes place,and a component layer,which contains all relevant components and cavities of the building represented with mass-averaged material *** has become apparent that the three parameters—albedo,heat capacity and thermal resistance—which have a decisive infuence on the interaction,have diferent efects on the component temperatures and the surface *** the second part of this research work,dynamic 3D computational fuid dynamics(CFD)simulations are performed with uhiSolver for a residential block in *** the simulation results with measurement data collected on site,it is shown that the simplifed assumption of homogeneous material data for building bodies provides very good results for the validation case ***,the infuence of the greening measures in the courtyard of the residential block on the air temperature is found to be ***,it was observed that due to locally higher radiation density,lower air velocities and higher air humidity,the apparent temperature in the courtyard is sometimes perceived to be higher than in the adjacent streets,despite the lower air ***:Simplifying the modeling process of the uhiSolver software by reducing the model complexity helps to reduce

关键词： Urban heat island efect Urban microclimate CFD simulation Microclimate simulation Apparent temperature

Towards optimal treatment of ductal carcinoma in situ

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World Journal of Clinical Oncology 2014年第3期5卷 194-196页

作者： christina Choy Kefah Mokbel The London Breast Institute The Princess Grace Hospital

Ductal carcinoma in situ(DCIS) is a non-obligate precursor of invasive breast cancer with a variable biological behavior which is difficult to accurately predict using the current clinico-pathological parameters. Randomized controlled trials have demonstrated that adjuvant radiotherapy(RT) reduces the risk of local recurrence after adequate local excision of DCIS. Tamoxifen may be considered as an adjuvant endocrine treatment in patients with high risk estrogen receptor positive disease. There is however a growing consensus that RT can be safely omitted in a subgroup of patients with favorable biological features in order to avoid overtreatment. The sentinel node biopsy is not routinely indicated but should be considered in women undergoing mastectomy for DCIS. The discovery of molecular signatures that accurately predict the biological behavior of this common malignancy will facilitate a personalized treatment approach in the future.

关键词： Ductal carcinoma in situ Treatment Radiotherapy Tamoxifen

Change in cap rock porosity triggered by pressure and temperature dependent CO_(2)-water-rock interactions in CO_(2) storage systems

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Petroleum 2017年第1期3卷 96-108页

作者： christina Hemme Wolfgang van Berk TU Clausthal Institute of Disposal ResearchDepartment of HydrogeologyLeibnizstrasse 1038642 Clausthal-ZellerfeldGermany

Carbon capture and storage in deep geological formations is a method to reduce greenhouse gas *** CO_(2) is injected into a reservoir and dissolves in the *** the impact of pressure and temperature(P-T)the aqueous species of the CO_(2)-acidified brine diffuse through the cap rock where they trigger CO_(2)-watererock *** geochemical reactions result in mineral dissolution and precipitation along the CO_(2) migration path and are responsible for a change in porosity and therefore for the sealing capacity of the cap *** study focuses on the diffusive mass transport of CO_(2) along a gradient of decreasing PeT *** process is retraced with a one-dimensional hydrogeochemical reactive mass transport *** semigeneric hydrogeochemical model is based on chemical equilibrium *** on a broad variety of scenarios,including different initial mineralogical,chemical and physical parameters,the hydrogeochemical parameters that are most sensitive for safe long-term CO_(2) storage are *** results demonstrate that PeT conditions have the strongest effect on the change in porosity and the effect of both is stronger at high PeT conditions because the solubility of the mineral phases involved depends on PeT ***,modeling results indicate that the change in porosity depends strongly on the initial mineralogical composition of the reservoir and cap rock as well as on the brine ***,a wide range of conditions for safe CO_(2) storage is identified.

关键词： rock reservoir geochemical

Integrating insulin-like growth factor 1 and sex hormones into neuroprotection:Implications for diabetes

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World Journal of Diabetes 2017年第2期8卷 45-55页

作者： Jacob Huffman christina Hoffmann George T Taylor Behavioral Neuroscience Program Department of Psychological SciencesUniversity of MissouriSt. Interfakultare Biomedizinische Forschung-seinrichtung der Universitat Heidelberg

Brain integrity and cognitive aptitude are often impaired in patients with diabetes mellitus, presumably a result of the metabolic complications inherent to the disease. However, an increasing body of evidence has demonstrated the central role of insulin-like growth factor 1(IGF1) and its relation to sex hormones in many neuroprotective processes. Both male and female patients with diabetes display abnormal IGF1 and sexhormone levels but the comparison of these fluctuations is seldom a topic of interest. It is interesting to note that both IGF1 and sex hormones have the ability to regulate phosphoinositide 3-kinase-Akt and mitogen-activated protein kinases-extracellular signal-related kinasesignaling cascades in animal and cell culture models of neuroprotection. Additionally, there is considerable evidence demonstrating the neuroprotective coupling of IGF1 and estrogen. Androgens have also been implicated in many neuroprotective processes that operate on similar signaling cascades as the estrogen-IGF1 relation. Yet, androgens have not been directly linked to the brain IGF1 system and neuroprotection. Despite the sex-specific variations in brain integrity and hormone levels observed in diabetic patients, the IGF1-sex hormone relation in neuroprotection has yet to be fully substantiated in experimental models of diabetes. Taken together, there is a clear need for the comprehensive analysis of sex differences on brain integrity of diabetic patients and the relationship between IGF1 and sex hormones that may influence brain-health outcomes. As such, this review will briefly outline the basic relation of diabetes and IGF1 and its role in neuroprotection. We will also consider the findings on sex hormones and diabetes as a basis for separately analyzing males and females to identify possible hormone-induced brain abnormalities. Finally, we will introduce the neuroprotective interplay of IGF1 and estrogen and how androgen-derived neuroprotection operates through similar si

关键词： Diabetes Androgens Estrogen Insulin Insulin-like growth factor 1 Neuroprotection Brain integrity Cognition