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The effects of temperature and resource availability on denitrification and relative N_(2)O production in boreal lake sediments

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j.urnal of Environmental Sciences 2016年第9期28卷 82-90页

作者： Maria Myrstener Anders j.nsson Ann-kristin Bergstrom Department of Ecology and Environmental Science Umea University90187 UmeaSweden

Anthropogenic environmental stressors（like atmospheric deposition,land use change,and climate warming） are predicted to increase inorganic nitrogen and organic carbon loading to northern boreal lakes,with potential consequences for denitrification in ***,our ability to predict effects of these changes is currently limited as northern boreal lakes have been largely neglected in denitrification *** aim of this study was therefore to assess how maximum potential denitrification and N_2O production rates,and the relationship between the two（relative N_2O production）,is controlled by availability of nitrate（NO_3^-）,carbon（C）,phosphorus（P）,and *** were performed using the acetylene inhibition technique on sediments from a small,nutrient poor boreal lake in northern Sweden in *** potential denitrification and N_2O production rates at 4°C were reached already at NO_3^-additions of 106–120 μg NO_3^-–N/L,and remained unchanged with higher NO_3 *** incubation temperatures increased maximum potential denitrification and N_2O production rates,and Q10 was somewhat higher for N_2O production（1.77） than for denitrification（1.69）.The relative N_2O production ranged between 13% and 64%,and was not related to NO_3^-concentration,but the ratio increased when incubations were amended with C and P（from a median of 16% to 27%）.Combined,our results suggests that unproductive northern boreal lakes currently have low potential for denitrification but are susceptible to small changes in NO_3 loading especially if these are accompanied by enhanced C and P availability,likely promoting higher N_2O production relative to N_2.

关键词： Acetylene NO3 Carbon DOC Nitrous oxide ratio Sediment

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j.urnal of Sport and Health Science 2023年第3期12卷 414-422页

作者： j.seph M.Bano Rebecca j.McAdams kristin j.Roberts j.ngzhen Yang Lara B.McKenzie Center for Inj.ry Research and Policy Abigail Wexner Research Institute at Nationwide Children's HospitalColumbusOH 43205USA Department of Pediatrics The Ohio State UniversityCollege of MedicineColumbusOH 43205USA Division of Epidemiology The Ohio State UniversityCollege of Public HealthColumbusOH 43210USA

Background:Lacrosse is one of the fastest-growing sports in the United *** rules regarding permitted contact differ by sex and *** are no known studies using a nationally representative data set to analyze lacrosse inj.ry patterns over several years by sex and age in the youth ***:A retrospective analysis was performed using data from the National Electronic Inj.ry Surveillance System for youth aged 11-18 years who were treated for lacrosse-related inj.ries in *** departments from 2000 to *** on our review of the case narratives,we created and coded a new inj.ry-mechanism *** generated national estimates from 6406 ***:An estimated 206,274 lacrosse-related inj.ries to youths aged 11-18 years were treated in *** departments from 2000 to *** rate of inj.ries per 10,000 significantly increased from 1.9 in 2000 to a peak of 5.3 in 2012(pj.ry mechanism,body part inj.red,and diagnosis differed by *** were 1.62 times(95%confidence interval(95%CI):1.25-2.09)more likely than girls to be inj.red by player-to-player *** were 2.21 times(95%CI:1.96-2.49)more likely than boys to have non-contact ***,as age increased,the percentage of inj.ries from lacrosse sticks decreased and player-toplayer contact ***:Despite additional protective regulations in the sport,lacrosse is an important source of inj.ry where we continue to see differences by sex and *** study supports the continuation,modification,and addition of rules aimed at reducing lacrosse inj.ry risk.

关键词： Lacrosse National Electronic Inj.ry Surveillance System Sex differences Youth inj.ries

Urban Forest and Tree Valuation Using Discounted Cash Flow Analysis: Impact of Economic Components

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Open j.urnal of Forestry 2012年第3期2卷 174-181页

作者： kristin S. Peterson Thomas j. Straka School of Agricultural Forest and Environmental Sciences Clemson University Clemson USA

Discounted cash flow analysis is one of the standard methods used to value urban forests and trees. It involves calculating today’s value for all benefits and costs attributed to an investment;that is discounting all cash flows to today’s value using an appropriate interest rate. This requires each benefit and cost be stated in terms of its cash flow. Urban tree benefits are complex. Little notice is given to the components of these benefits. Total urban tree benefits are a summation of partial benefits, including property value increase, storm water reduction, air quality improvement, carbon sequestration, natural gas savings, and electricity savings. We discuss the nature of these partial benefits, especially the geographical, temporal, diameter size, and rate of growth differences. These differences are even reflected in nursery stock valuation. Net present value analysis is used to illustrate the impact of these differences on financial return. An understanding of these components will prove valuable to those attempting to estimate urban forest and tree benefits.

关键词： Urban Forest Benefits Costs Economic Components Discounted Cash Flow Analysis Arboriculture

Solvation Effects on the Dielectric Constant of 1 M LiPF6 in Ethylene Carbonate:Ethyl Methyl Carbonate 3:7

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Energy & Environmental Materials 2024年第1期7卷 253-256页

作者： j.lian Self Nathan T.Hahn kristin A.Persson Department of Chemical Engineering Polytechnique MontrealMontrealQC H3T 1J4Canada Department of Materials Science and Engineering University of CaliforniaBerkeleyCA 94720USA Energy Technologies Area Lawrence Berkeley National LaboratoryBerkeleyCA 94720USA Material Physical and Chemical Sciences CenterSandia National LaboratoriesAlbuquerqueNM 87185USA

We report the dielectric constant of 1 M LiPF_(6)in EC:EMC 3∶7 w/w(ethylene carbonate/ethyl methyl carbonate)in addition to neat EC:EMC 3∶7 w/*** three Debye relaxations,the static permittivity value,or dielectric constant,is extrapolated to 18.5,which is compared to 18.7 for the neat solvent *** EC solvent is found to strongly coordinate with the Li^(+)cations of the salt,which results in a loss of dielectric contribution to the ***,the small amplitude and large uncertainty in relaxation frequency for EMC cloud definitive identification of the Li^(+)solvation ***,the loss of the free EC permittivity contribution due to Li^(+)solvation is almost completely balanced by the positive contribution of the associated LiPF_(6)salt,demonstrating that a significant quantity of dipolar ion pairs exists in 1 M LiPF_(6)in EC:EMC 3∶7.

关键词： batteries dielectric relaxation spectroscopy electrolytes

Color change in a marine isopod is adaptive in reducing predation

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Current Zoology 2015年第4期61卷 739-748页

作者： kristin M. HULTGREN Hannah MITTELSTAEDT Department of Biology Seattle University 901 12^th ave. Seattle WA 98122

Although background matching is a common form of camouflage across a wide diversity of animals, there has been surprisingly little experimental work testing the fitness consequences of this camouflage strategy, especially in marine ecosystems. In this study, we tested whether color camouflage enhances survival of the intertidal marine isopod Pentidotea （Idotea） wosnesenskii, quantified patterns of camouflage in different algal habitats, and examined how algal diet affected color change and growth using laboratory assays. In the field, isopods collected from two differently colored algal habitats （the brown alga Fucus distichus and the red alga Odonthaliafloccosa） matched the color of their respective algal habitats, and also differed significantly in body size： smaller red isopods were found on red algae, while larger brown isopods were found on brown algae. Predation ex- periments demonstrated these color differences had fitness benefits： brown isopods that matched their brown algae habitats sur- vived at higher rates than red unmatched isopods. Surprisingly, despite the propensity of isopods to match their algal habitats, algal diet had no effect on color change in color change experiments. Instead, isopods in all treatments turned browner, matching the color of the algal habitat that many isopods are found on as adults. In summary, our data supported our hypothesis that back- ground matching serves an adaptive function in reducing predation, with important evolutionary implications for explaining the wide variation in color change mechanisms in idoteid isopods [Current Zoology 61 （4）： 739-748, 2015].

关键词： Isopod Pentidotea wosnesenskii. Camouflage Crypsis Background matching Color change

Potential underlying genetic associations between keratoconus and diabetes mellitus

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Advances in Ophthalmology Practice and Research 2021年第1期1卷 15-31页

作者： kristin M.Ates Amy j.Estes Yutao Liu Department of Cellular Biology and Anatomy Medical College of GeorgiaAugusta UniversityAugustaGAUSA Department of Ophthalmology Medical College of GeorgiaAugusta UniversityAugustaGAUSA j.mes and j.an Culver Vision Discovery Institute Medical College of GeorgiaAugusta UniversityAugustaGAUSA Center for Biotechnology and Genomic Medicine Medical College of GeorgiaAugusta UniversityAugustaGAUSA

Background:Keratoconus(KC)is the most common ectatic corneal disease,characterized by significantly localized thinning of the corneal ***,environmental,hormonal,and metabolic factors contribute to the pathogenesis of ***,multiple comorbidities,such as diabetes mellitus,may affect the risk of *** Text:Patients with diabetes mellitus(DM)have been reported to have lower risk of developing KC by way of increased endogenous collagen crosslinking in response to chronic ***,this remains a debated topic as other studies have suggested either a positive association or no association between DM and *** gain further insight into the underlying genetic components of these two diseases,we reviewed candidate genes associated with KC and central corneal thickness in the *** then explored how these genes may be regulated similarly or differentially under hyperglycemic conditions and the role they play in the systemic complications associated with ***:Our comprehensive review of potential genetic factors underlying KC and DM provides a direction for future studies to further determine the genetic etiology of KC and how it is influenced by systemic diseases such as diabetes.

关键词： Keratoconus Genetics Diabetes Collagen crosslinking Oxidative stress

CFD-DEM simulation and experimental investigation of the flow behavior of lunar regolith j.C-1A

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Particuology 2018年第5期16卷 34-43页

作者： Hendrik Otto kristin Kerst Christoph Roloff Gabor j.niga Andre Katterfeld Chair of Conveying Technologies University of Magdeburg "Otto yon Guericke'MagdeburgGermany Laboratory of Fluid Dynamics and Technical Flows University of Magdeburg "Otto yon Guericke"MagdeburgGermany

Rovers on Mars and the Moon analyze the local geology by collecting samples of the upper layer in containers and *** the analysis,the complete discharge of samples from the reservoir must be *** of the low atmospheric pressure,reduced gravity,and different grain shapes of the bulk material,the discharge process is very different compared to that on *** this study,the behavior of lunar regolith j.C-1A in closed containers during discharge was investigated by analyzing the flow in an hourglass under the Earth's *** fluidization of the top particle layer was observed during the outflow of the upper half of the *** particles were fluidized by the displacement flow initiated by failing particles in the completely closed *** complex problem was simulated by coupling computational fluid dynamics (CFD)with the discrete element method (DEM). A CFD-DEM simulation with 1million particles was *** billions of particles are present in the actual system,the use of a coarse graining approach was *** addition,high-speed camera measurements were used to determine the velocities of individual particles to validate the simulation. The fluidization effect was successfully simulated using the coupled method.

关键词： CFD-DEM simulation Flow behavior Lunar regolith j.C-1A Experiment

Integration of solid phase extraction with HILIC-MS/MS for analysis of free amino acids in source water

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j.urnal of Environmental Sciences 2022年第7期34卷 190-196页

作者： j.nlang Qiu Caley Craven Nicholas Wawryk kristin Carroll Xing-Fang Li Division of Analytical and Environmental Toxicology Department of Laboratory Medicine and PathologyUniversity of AlbertaEdmontonT6G 2G3Canada School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510006China

Amino acids(AAs) are prevalent in source water, particularly during spring run-off. Monitoring of amino acids in source water is desirable for water treatment plants(WTP) to indicate changes in source water quality. The obj.ctive of this study was to establish analytical procedures for reliable monitoring of amino acids in source water. Therefore, we examined two different methods, large volume inj.ct(LVI) and solid phase extraction(SPE), for sample preparation prior to HILIC-MS/MS. The LVI-HILIC-MS/MS method can provide fast and sensitive detection for clean samples, but suffers from matrix effects, resulting in irreproducible separation and shortening column lifetime. We have demonstrated that SPE was necessary prior to HILIC-MS/MS to achieve reproducible and reliable quantification of AAs in source water. A natural heterocyclic amine 1-methyl-1,2,3,4-tetrahydro-β-carboline-3-carboxylic acid(MTCCA) was also included in the method to indicate changes in other natural nitrogenous compounds in source water. The SPE-HILIC-MS/MS method was able to achieve limits of detection from 2.6-3400 ng/L for the amino acids and MTCCA with RSDs( n = 3) of 1.1%-4.8%. As well, retention times(RT) of the analytes were reproducible with variation less than 0.01 min( n = 3) through the entire proj.ct. We further applied the SPE-HILICMS/MS method to determine AAs in authentic source water samples collected from two drinking water treatment plants(WTPs) during the 2021 spring run-off season. The results support that the SPE-HILIC-MS/MS method does not require derivatization and can provide reliable, accurate, and robust analysis of AAs and MTCCA in source water, supporting future monitoring of source water quality.

关键词： Water analysis Disinfection byproducts Amino acids HPLC MS HILIC