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Vole preference of bilberry along gradients of simulated moose density and site productivity

Integrative Zoology 2011年第4期6卷 341-351页

作者： simen pedersen Harry P.ANDREASSEN Inga-Lill PERSSON Riitta JULKUNEN-TIITTO Kjell DANELL Christina SKARPE Department of Forestry and Wildlife Management Hedmark University CollegeKoppangNorway Department of Biology Norwegian University of Science and TechnologyTrondheimNorway Department of Wildlife Fish and Environmental StudiesSwedish University of Agricultural SciencesUmeåSweden Department of Biology University of Eastern FinlandJoensuuFinland

Browsing by large herbivores might either increase or decrease preference for the plant by other herbivores,depending on the plant *** a cafeteria test,we studied the preference by root voles(Microtus oeconomus[Pallas,1776])for bilberry(Vaccinium myrtillus L.)previously subjected to 4 levels of simulated moose(Alces alces[Linnaeus,1758])*** different levels of moose density were simulated at population densities relevant for Fennoscandian conditions,in exclosures situated along a site productivity *** expected:(i)voles to prefer bilberry from high productivity sites over low productivity sites;(ii)voles to prefer browsed bilberry,if plants allocate resources to compensatory growth or to avoid browsed bilberry if plants allocate resources to defense;(iii)these effects to increase with increasing simulated moose density;and(iv)the concentration of plant chemicals and the plant morphology to explain vole ***,we predicted that voles would prefer:(i)plants with high nitrogen content;(ii)plants with low content of defensive substances;and(iii)tall plants with long *** preferred bilberry from the high productivity sites compared to the low productivity *** also found an interaction between site productivity and simulated moose density,where voles preferred unbrowsed plants at low productivity sites and intermediate levels of browsing at high productivity *** was no effect of plant chemistry or morphology on vole *** conclude that moose browsing impacts the food preference of *** the current high densities of moose in Fennoscandia,this could potentially influence vole food selection and population dynamics over large geographical areas.

关键词： browsing cervid herbivory induced defense Microtus

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Prevalence of cardiometabolic co-morbidities in patients with vs persons without chronic hepatitis B: The FitLiver cohort study

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World Journal of Hepatology 2025年第1期17卷 73-85页

作者： Sofie Jespersen Asmita Fritt-Rasmussen Sten Madsbad Bente K pedersen Rikke Krogh-Madsen Nina Weis Department of Infectious Diseases Copenhagen University HospitalHvidovreDenmark Centre for Physical Activity Research Copenhagen University HospitalRigshospitaletDenmark Department of Endocrinology Copenhagen University HospitalHvidovreDenmark

BACKGROUND Chronic hepatitis B(CHB)affects>300 million people *** combi-nation of CHB and cardiometabolic co-morbidities increases the risk of liver-related morbidity and ***,international guidelines for CHB treatment do not provide recommendations for follow-up examinations or treatment of patients with CHB and cardiometabolic *** studies investigating cardiometabolic co-morbidity in patients with CHB,inconsistent findings have been observed,and both lower and higher prevalence of car-diometabolic co-morbidities compared to the general population have been *** is unclear whether patients with CHB living in Denmark have an increased prevalence of cardiometabolic *** examined patients with CHB and age-,sex-,body mass index(BMI)-,and country-of-birth matched comparison *** cardiometabolic co-morbidity:Obesity(BMI>25 kg/m2/abnormal waist-to-hip ratio),metabolic dysfunction-associated steatotic liver disease(MASLD),hypercholesterolemia(total-cholesterol>5 mmol/L/statin use),hypertension(systolic≥135 mmHg/diastolic≥85 mmHg/antihypertensive medication)and type 2 diabetes(T2D)(2-hour oral glucose tolerance test glucose>11.1 mmol/L/HbA1c>48 mmol/mol/antidiabetic medication).Physical activity was evaluated using maximal oxygen consumption(VO2max),activity monitors,and a *** We included 98 patients with CHB and 49 persons in the comparison *** two groups were well-matched,showing no significant differences in age,sex,BMI,country-of-birth,education,or *** patients with CHB,the following prevalence of cardiometabolic co-morbidity was found:77%were obese,45%had MASLD,38%had hypercholesterolemia,26%had hypertension,and 7%had T2D,which did not differ significantly from the comparison group,apart from lower prevalence of hemoglobin A1c(HbA1c)≥48 mmol/L or known *** groups had low VO2max of 27 mL/kg/minute in the patients with CHB and 30 mL/kg/minute in the comparison gro

关键词： Viral hepatitis B Diabetes Metabolic dysfunction-associated steatotic liver disease Hypertension Hypercholesterolemia Obesity Physical activity

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PARAMETER ESTIMATION FOR A DISCRETELY OBSERVED STOCHASTIC VOLATILITY MODEL WITH JUMPS IN THE VOLATILITY

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Chinese Annals of Mathematics,Series B 2003年第2期24卷 227-238页

作者： JIANGWENJIANG J.pedersen SchoolofMathematicalScience YunnanNormalUniversityKunming650092China. InstituteofMathematicalSciences UniversityofAarhusAarhusDenmark.

In this paper a stochastic volatility model is considered. That is, a log price process Y whichis given in terms of a volatility process V is studied. The latter is defined such that the logprice possesses some of the properties empirically observed by Barndorff-Nielsen & Jiang[6]. Inthe model there are two sets of unknown parameters, one set corresponding to the marginaldistribution of V and one to autocorrelation of V. Based on discrete time observations ofthe log price the authors discuss how to estimate the parameters appearing in the marginaldistribution and find the asymptotic properties.

关键词： Stochastic volatility models NIG distributions Central limit theorems Law of large numbers Levy processes Ornstein-Uhlenbeck processes

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Experimental Study of Stable Surfaces for Anti-Slug Control in Multi-phase Flow

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International Journal of Automation and computing 2016年第1期13卷 81-88页

作者： Simon pedersen Petar Durdevic Kasper Stampe Sandra Lindberg pedersen Zhenyu Yang Department of Energy Technology Aalborg University Esb jerg Campus

Severe slugging flow is always challenging in oil ＆ gas production, especially for the current offshore based production. The slugging flow can cause a lot of problems, such as those relevant to production safety~ fatigue as well as capability. As one typical phenomenon in multi-phase flow dynamics, the slug can be avoided or eliminated by proper facility d^sign or control of operational conditions. Based on a testing facility which can emulate a pipeline-riser or a gas-lifted production well in a scaled-down manner, this paper experimentally studies the correlations of key operational parameters with severe Slugging flows. These correlations are reflected through an obtained stable surface in the parameter space, which is a natural extension of the bifurcation plot. The maximal production opportunity without compromising the stability is also studied. Relevant studies have already showed that the capability, performance and efficiency of anti-slug control can be dramatically improved if these stable surfaces can be experimentally determined beforehand. The paper concludes that obtaining the stable surface on the new developed map can significantly improve the production rate in a control scheme. Even though the production rate can be further improved by moving the stable surface using advanced control strategies, the constant inputs can in some cases be preferable due to the easier implementation.

关键词： Offshore oil and gas anti-slug flow control production-rate optimization stabilization bifurcation.

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Identifying factors controlling the selective ethane dehydrogenation on Pt-based catalysts from DFT based micro-kinetic modeling

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Journal of Energy Chemistry 2021年第7期30卷 37-40页

作者： Tao Wang Frank Abild-pedersen SUNCAT Center for Interface Science and Catalysis Department of Chemical EngineeringStanford UniversityStanfordCalifornia 94305USA SUNCAT Center for Interface Science and Catalysis Stanford Linear Accelerator CenterMenlo ParkCalifornia 94025USA

Light olefins such as ethylene and propylene are important industrial feedstocks, having essential applications in the production of plastics, ethylbenzene, and ethylene dichloride [1]. Compared with the conventional route, in which alkane steam cracking (SC) at high temperature is applied to produce ethylene and propylene, the catalytic ethane/propane non-oxidative dehydrogenation (EDH/PDH) possess the advantages of high selectivity and low energy consumption. Industrially, Pt is the major component to catalyze this reaction, but it suffers from low selectivity and fast deactivation because of favorable coke formation [2].

关键词： Ethane dehydrogenation DFT Micro-kinetic modeling Selectivity Pt

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Electronic structure factors and the importance of adsorbate effects in chemisorption on surface alloys

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npj Computational Materials 2022年第1期8卷 1560-1571页

作者： Shikha Saini Joakim Halldin Stenlid Frank Abild-pedersen SUNCAT Center for Interface Science and Catalysis Department of Chemical EngineeringStanford University443 Via OrtegaStanfordCA94305USA SUNCAT Center for Interface Science and Catalysis SLAC National Accelerator Laboratory2575 Sand Hill RoadMenlo ParkCA94025USA

The chemisorption energy is an integral aspect of surface chemistry,central to numerous fields such as catalysis,corrosion,and ***-structure-based methods such as the Newns-Anderson model are therefore of great importance in guiding the engineering of material surfaces with optimal ***,existing methods are inadequate for interpreting complex,multi-metallic ***,we introduce a physics-based chemisorption model for alloyed transition metal surfaces employing primarily metal d-band properties that accounts for perturbations in both the substrate and adsorbate electronic states upon ***,we show that adsorbate-induced changes in the adsorption site interact with its chemical environment leading to a second-order response in chemisorption energy with the d-filling of the neighboring *** demonstrate the robustness of the model on a wide range of transition metal alloys with O,N,CH,and Li adsorbates yielding a mean absolute error of 0.13 eV versus density functional theory reference chemisorption energies.

关键词： alloys corrosion chemisorption

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Battery impedance spectrum prediction from partial charging voltage curve by machine learning

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Journal of Energy Chemistry 2023年第4期79卷 211-221页

作者： Jia Guo Yunhong Che Kjeld pedersen Daniel-Ioan Stroe AAU Energy Aalborg UniversityAalborg 9220Denmark Department of Materials and Production Aalborg UniversityAalborg 9220Denmark

Electrochemical impedance spectroscopy(EIS) is an effective technique for Lithium-ion battery state of health diagnosis, and the impedance spectrum prediction by battery charging curve is expected to enable battery impedance testing during vehicle operation. However, the mechanistic relationship between charging curves and impedance spectrum remains unclear, which hinders the development as well as optimization of EIS-based prediction techniques. In this paper, we predicted the impedance spectrum by the battery charging voltage curve and optimized the input based on electrochemical mechanistic analysis and machine learning. The internal electrochemical relationships between the charging curve,incremental capacity curve, and the impedance spectrum are explored, which improves the physical interpretability for this prediction and helps define the proper partial voltage range for the input for machine learning models. Different machine learning algorithms have been adopted for the verification of the proposed framework based on the sequence-to-sequence predictions. In addition, the predictions with different partial voltage ranges, at different state of charge, and with different training data ratio are evaluated to prove the proposed method have high generalization and robustness. The experimental results show that the proper partial voltage range has high accuracy and converges to the findings of the electrochemical analysis. The predicted errors for impedance spectrum are less than 1.9 mΩ with the proper partial voltage range selected by the corelative analysis of the electrochemical reactions inside the batteries. Even with the voltage range reduced to 3.65–3.75 V, the predictions are still reliable with most RMSEs less than 4 mO.

关键词： Impedance spectrum prediction Lithium-ion battery Machine learning EIS Graphite anode

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Electromembrane extraction–Recent trends and where to go

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Journal of Pharmaceutical Analysis 2017年第3期7卷 141-147页

作者： Stig pedersen-Bjergaard Chuixiu Huang Astrid Gjelstad School of Pharmacy University of Oslo Faculty of Health and Medical Sciences School of Pharmaceutical Sciences University of Copenhagen

Electromembrane extraction(EME) is an analytical microextraction technique, where charged analytes(such as drug substances) are extracted from an aqueous sample(such as a biological fluid), through a supported liquid membrane(SLM) comprising a water immiscible organic solvent, and into an aqueous acceptor solution. The driving force for the extraction is an electrical potential(dc) applied across the SLM. In this paper, EME is reviewed. First, the principle for EME is explained with focus on extraction of cationic and anionic analytes, and typical performance data are presented. Second, papers published in 2016 are reviewed and discussed with focus on(a) new SLMs,(b) new support materials for the SLM,(c) new sample additives improving extraction,(d) new technical configurations,(e) improved theoretical understanding, and(f) pharmaceutical new applications. Finally, important future research objectives and directions are defined for further development of EME, with the aim of establishing EME in the toolbox of future analytical laboratories.

关键词： Sample preparation Microextraction Electromembrane extraction

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Lee pedersen's work in theoretical and computational chemistry and biochemistry

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World Journal of Biological Chemistry 2011年第2期2卷 35-38页

作者： Lee G pedersen Department of Chemistry University of North Carolina at Chapel Hill

Nature at the lab level in biology and chemistry can be described by the application of quantum *** many cases,a reasonable approximation to quantum mechanics is classical mechanics realized through Newton's equations of *** began his career using quantum mechanics to describe the properties of small molecular complexes that could serve as models for biochemical *** describe large molecular systems required a drop-back to classical means and this led surprisingly to a major improvement in the classical treatment of electrostatics for all molecules,not just biological *** work has involved the application of quantum mechanics for the putative active sites of enzymes to gain greater insight into the key steps in enzyme catalysis.

关键词： Blood coagulation cascade Classical mechanics DNA repair enzymes Particle mesh Ewald Quantum mechanical/molecular mechanical Quantum mechanics

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Axially variable-length solid element of absolute nodal coordinate formulation

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Acta Mechanica Sinica 2019年第3期35卷 653-663页

作者： Jialiang Sun Qiang Tian Haiyan Hu Niels L.pedersen State Key Laboratory of Mechanics and Control of Mechanical Structures College of Aerospace EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China MOE Key Laboratory of Dynamics and Control of Flight Vehicle School of Aerospace EngineeringBeijing Institute of TechnologyBeijing 100081China Department of Mechanical Engineering Solid MechanicsTechnical University of Denmark2800 Kongens LyngbyDenmark

An axially variable-length solid element with eight nodes is proposed by integrating the arbitrary Lagrangian-Eulerian (ALE) formulation and the absolute nodal coordinate formulation (ANCF). In addition to the nodal positions and slopes of eight nodes, two material coordinates in the axial direction are used as the generalized coordinates. As a consequence, the nodes in the ALE-ANCF are not associated with any specific material points and the axial length of the solid element can be varied over time. These two material coordinates give rise to a variable mass matrix and an additional inertial force vector. Computationally efficient formulae of the additional inertial forces and elastic forces, as well as their Jacobians, are also derived. The dynamic equation of a flexible multibody system (FMBS) with variable-length bodies is presented. The maximum and minimum lengths of the boundary elements of an FMBS have to be appropriately defined to ensure accuracy and non-singularity when solving the dynamic equation. Three numerical examples of static and dynamic problems are given to validate the variable-length solid elements of ALE-ANCF and show their capability.

关键词： Flexible multibody dynamics Arbitrary Lagrangian-Eulerian formulation Absolute nodal coordinate formulation Variable-length solid element

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