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Influence of flooding and vegetation on carbon,nitrogen,and phosphorus dynamics in the pore water of a Spartina alterniflora salt marsh

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Journal of environmental Sciences 2011年第2期23卷 212-221页

作者： Vanesa L.Negrin Carla V.Spetter Raúl O.Asteasuain gerardo m.e.perillo Jorge e.marcovecchio Argentine Institute of Oceanography (IADO CONICETCCT-Bahía Blanca)Camino La Carrindanga km 75Building E-1 CC 804Bahía Blanca 8000Argentina Department of Chemistry Southern National Institute of Chemistry (INQUISUR)Southern National University (UNS)Av Alem 1253Bahía Blanca 8000Argentina Department of Geology Southern National University (UNS)San Juan 670Bahía Blanca 8000Argentina National Technological University Regional Faculty of Bahía Blanca (UTN-FRBB)11 de Abril 461Bahía Blanca 8000Argentina University of the Fraternity of Associations Santo Toms de Aquino (FASTA) Gascón 3145Mar del Plata 7600Argentina

Four sites were selected in a salt marsh in the Bahia Blanca estuary （Argentina）：（1） low marsh （flooded by the tide twice daily） vegetated by S. alterniflora; （2） non-vegetated low marsh; （3） high marsh （flooded only in spring tides） vegetated by S. alterniflora; （4） non-vegetated high marsh. The pH and eh were measured in sediments, while dissolved nutrients （ammonium, nitrate, nitrite and phosphate） and particulate organic matter （POm） were determined in pore water, pH （6.2-8.7） was only affected by vegetation in low areas. eh （from -300 to 250 mV） was lower at low sites than at high ones; in the latter, the values were higher in the non-vegetated sediments. The POm concentration was greater in the high marsh than in the low marsh, with no effect of vegetation. Ammonium was the most abundant nitrogen nutrient species in pore water, except in the non-vegetated high marsh where nitrate concentration was higher. All nitrogen nutrients were affected by both flooding and vegetation. Phosphate was always present in pore water at all sites throughout the year and its concentration varied within narrow limits, with no effect of flooding and greater values always at non-vegetated sites. Our results showed that the variability of the pore water composition within the marsh is greater than the temporal variation, meaning that both tidal flooding and vegetation are important in the dynamics of nutrients and organic matter in the sediment pore water.

关键词： organic matter nutrients flooding Spartina alterniflora

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A simple method for automatic recreation of railway horizontal alignments

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Railway engineering Science 2025年第1期33卷 62-78页

作者： Alberte Castro gerardo Casal Duarte Santamarina miguel e.Vázquez‑méndez Transportation and Infrastructure engineering Universidade de Santiago de CompostelaEPSERúa Benigno Ledo27002 LugoSpain Department of Applied mathematics Universidade de Santiago de CompostelaEPSERúa Benigno Ledo27002 LugoSpain CITmAga Rúa de Constantino Candeira15782 Santiago de CompostelaSpain

This paper deals with the problem of recreating horizontal alignments of existing railway *** main objective is to propose a simple method for automatically obtaining optimized recreated alignments located as close as possible to an existing *** on a previously defined geometric model,two different constrained optimization problems are *** first problem uses only the information provided by a set of points representing the track centerline while the second one also considers additional data about the existing *** proposed methodology consists of a two-stage process in which both problems are solved consecutively using numerical *** main results obtained applying this methodology are presented to show its performance and to prove its practical usefulness:an academic example used to compare with other methods,and a case study of a railway section located in Parga(Spain)in which the geometry of its horizontal alignment is successfully recovered.

关键词： Railway horizontal alignment Geometrical model Constrained optimization problem Numerical resolution

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A simple method for automatic recreation of railway horizontal alignments

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Railway engineering Science 2025年第1期 62-78页

作者： Alberte Castro gerardo Casal Duarte Santamarina miguel e.Vázquez-méndez Transportation and Infrastructure engineering Universidade de Santiago de Compostela EPSE Department of Applied mathematics Universidade de Santiago de Compostela EPSE CITmAga Rúa de Constantino Candeira 15782 Santiago de Compostela

This paper deals with the problem of recreating horizontal alignments of existing railway lines. The main objective is to propose a simple method for automatically obtaining optimized recreated alignments located as close as possible to an existing one. Based on a previously defined geometric model, two different constrained optimization problems are formulated. The first problem uses only the information provided by a set of points representing the track centerline while the second one also considers additional data about the existing alignment. The proposed methodology consists of a two-stage process in which both problems are solved consecutively using numerical techniques. The main results obtained applying this methodology are presented to show its performance and to prove its practical usefulness: an academic example used to compare with other methods, and a case study of a railway section located in Parga(Spain) in which the geometry of its horizontal alignment is successfully recovered.

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Analysis and Validation for an Inverter-side Current Controller in LCL Grid-connected Power Systems

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Journal of modern Power Systems and Clean energy 2020年第2期8卷 387-398页

作者： Jose mSosa Panfilo R.martinez-Rodriguez gerardo escobar gerardo Vazquez Andres A.Valdez-Fernandez Juan F.martinez-Garcia the Tecnologico Nacional de mexico/ITS de Irapuato(TecNm/ITeSI) IrapuatoGTO 36821Mexico the School of Sciences Autonomous University of San Luis Potosi(UASLP)San Luis PotosiSLP 78290Mexico Tecnologico de monterrey N.L.64849Mexico

Transformerless grid-connected inverters offer greater efficiencies when transferring power from renewable energy sources to the electrical *** the grid-inverter connection is done with an LCL filter,high attenuation of switching harmonics is achieved while preserving a small-size output ***,damping must be included in the controller to assure closed-loop *** paper proposes a reference computation methodology for the inverter-side current feedback in a photovoltaic(PV)generation system connected to the grid through an LCL *** analysis of the closed-loop system stability and of the steady-state performance are presented as well as experimental validation of the closed-loop *** feedback controller includes active damping and relies on a resonant control structure which improves the ability of dealing with grid harmonic *** controller uses a reduced set of measurements,which requires the inverter-side current and grid voltage only,and assures a power factor close to unity.

关键词： LCL filter transformerless inverter grid connection inverter-side current feedback

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Cholecystoenteric fistula with and without gallstone ileus: A case series

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Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 36-40页

作者： mauricio Gonzalez-Urquijo mario Rodarte-Shade gerardo Lozano-Balderas gerardo Gil-Galind Tecnologico de monterrey Escuela de MedicinaCiencias de la SaludDr.Ignacio Morones Prieto O 3000Monterrey 64710México Department of Surgery Hospital Metropolitano“Dr.Bernardo Sepúlveda”Secretaria de Salud de Nuevo LeónAdolfo López Mateos No.4600San Nicolás de los Garza 66400México

Background: A cholecystoenteric stula (CeF) is an uncommon complication of gallstone disease. The aim of this study was to present our experience of a series of patients with CeF, presenting with or without gallstone ileus, along with their surgical outcomes. methods: From 2015 to 2018, 3245 consecutive patients underwent cholecystectomy for gallbladder disease at our institution, of which 15 were diagnosed with a CeF. All electronic medical records were retrospectively reviewed. Results: Fifteen patients presented with CeF. Ten patients presented cholecystoduodenal stula, four pa- tients cholecystocolonic, and one patient cholecystogastric counterparts. Twelve patients were female. The median patient age was 61 years (range 33 86 years). Five patients presented with gallstone ileus treated by laparotomy and enterolithotomy. In ten patients, a laparoscopic approach was attempted, but conversion to open surgery was necessary for eight of them. The median operative time was 140 min (range 60 240 min), and the median operative blood loss was 50 mL (range 10600mL). The procedure-related morbidity and mortality rates were 13.3% and 6.7%, respectively. Conclusions: There is no consensus on the best treatment modality for a CeF, as the treatment outcome is mostly dependent on the surgeon’s expertise and the patient’s condition. Not all CeFs are accompanied by gallstone ileus. For such case, the main purpose is to resolve the intestinal obstruction and, unless necessary, avoidance of the gallbladder area.

关键词： Cholecystoenteric stula Gallbladder disease Biliary-enteric stula Gallstone ileus Intestinal obstruction

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model based current mode control design and experimental validation for a 3φ rectifier under unbalanced grid voltage conditions

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Journal of modern Power Systems and Clean energy 2018年第4期6卷 777-790页

作者： P.R.mARTíNeZ-RODRIGeZ Jose m.SOSA Samuel ITURRIAGA-meDINA gerardo eSCOBAR gerardo VáZQUeZ-GUZmáN Andres A.VALDeZ-FeRNáNDeZ School of Sciencies UASLP Laboratory of electrical and Power electronics ITESI School of engineering Universidad Modelo

This paper addresses the control design and the experimental validation of a current mode control for a three phase voltage source rectifier. The proposed control law is able to fulfill the voltage regulation and the current tracking control objectives despite of unbalanced and distorted grid voltages. The proposed control law consists of two loops, which are referred as inner tracking loop and the outer voltage regulation loop. The inner loop is designed to provide damping to the system, which also includes and adaptive mechanism. The construction of the current reference is based on the positive component detection of thegrid voltage. Therefore, the current produced by the power rectifier is proportional to the fundamental component of the grid voltage, despite of the presence of unbalanced grid voltages. The voltage regulation loop is designed as a proportional-integral controller, which is aimed to regulate the DC output voltage to a desired level. Finally, experimental results are obtained in an experimental prototype of2 kW to evaluate the performance of the proposed controller.

关键词： Pulse-width modulation rectifier Power factor correction Positive-component Current mode control

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Fitting dynamic models to epidemic outbreaks with quantified uncertainty:A primer for parameter uncertainty,identifiability,and forecasts

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Infectious Disease modelling 2017年第3期2卷 379-398页

作者： gerardo Chowell Division of epidemiology&Biostatistics School of Public HealthGeorgia State UniversityAtlantaGAUSA Division of International epidemiology and Population Studies Fogarty International CenterNational Institutes of HealthBethesdaMDUSA

mathematical models provide a quantitative framework with which scientists can assess hypotheses on the potential underlying mechanisms that explain patterns in observed data at different spatial and temporal scales,generate estimates of key kinetic parameters,assess the impact of interventions,optimize the impact of control strategies,and generate *** review and illustrate a simple data assimilation framework for calibrating mathematical models based on ordinary differential equation models using time series data describing the temporal progression of case counts relating,for instance,to population growth or infectious disease transmission *** contrast to Bayesian estimation approaches that always raise the question of how to set priors for the parameters,this frequentist approach relies on modeling the error structure in the *** discuss issues related to parameter identifiability,uncertainty quantification and propagation as well as model performance and forecasts along examples based on phenomenological and mechanistic models parameterized using simulated and real datasets.

关键词： Parameter estimation Uncertainty quantification Bootstrap Parameter identifiability model performance Forecasts Uncertainty propagation

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machine-learned coarse-grained potentials for particles with anisotropic shapes and interactions

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npj Computational materials 2024年第1期10卷 820-832页

作者： gerardo Campos-Villalobos Rodolfo Subert Giuliana Giunta marjolein Dijkstra Soft Condensed matter&Biophysics Debye Institute for Nanomaterials ScienceUtrecht UniversityPrincetonplein 53584 CC UtrechtThe Netherlands BASF Se Carl-Bosch-Strasse 3867056 Ludwigshafen am RheinGermany International Institute for Sustainability with Knotted Chiral meta matter(SKCm2) Hiroshima University2-313 KagamiyamaHigashi-HiroshimaHiroshima739-8527Japan

Computational investigations of biological and soft-matter systems governed by strongly anisotropic interactions typically require resource-demanding methods such as atomistic ***,these techniques frequently prove to be prohibitively expensive for accessing the long-time and largelength scales inherent to such ***,coarse-grained models offer a computationally efficient ***,models of this type have seldom been developed to accurately represent anisotropic or directional *** this work,we introduce a straightforward bottomup,data-driven approach for constructing single-site coarse-grained potentials suitable for particles with arbitrary shapes and highly directional *** method for constructing these coarsegrained potentials relies on particle-centered descriptors of local structure that effectively encode dependencies on rotational degrees of freedom in the *** using these descriptors as regressors in a linear model and employing a simple feature selection scheme,weconstruct single-site coarse-grained potentials for particles with anisotropic interactions,including surface-patterned particles and colloidal superballs in the presence of non-adsorbing *** validate the efficacy of our models by accurately capturing the intricacies of the potential-energy surfaces from the underlying fine-grained ***,we demonstrate that this simple approach can accurately represent the contact function(shape)of non-spherical particles,which may be leveraged to construct continuous potentials suitable for large-scale simulations.

关键词： anisotropic constructing straight

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Corrosion Behavior of Ψ and β Quasicrystalline Al–Cu–Fe Alloy

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Acta metallurgica Sinica(english Letters) 2015年第9期28卷 1117-1122页

作者： Alvaro Torres Sergio Serna Cristobal Patio gerardo Rosas Facultad de Ciencias Químicas e Ingeniería P.A. Ing.mecnica UAEM Av. Universidad 1001 Col. Chamilpa62210 Cuernavaca Mor. Mexico Centro de Investigación en Ingeniería y Ciencias Aplicadas UAEM Av. Universidad 1001 Col. Chamilpa62210 Cuernavaca Mor. Mexico Facultad de Ingeniería Universidad Autónoma del CarmenCampus Ⅲ Avenida Central S/N Esq. con Fracc. MundoMaya C.P. 24115 Ciudad del Carmen Campeche Mexico Instituto de Investigaciones metalurgicas UMSNH Edificio U. Ciudad Universitaria Morelia Mich. 58000 Mexico

Two nanostructured A1-Cu-Fe alloys, A164Cu24Fe12 and A162.5Cu25.2Fe12.3, have been studied. Icosahedral quasicrystalline （ψ） A164CH24FeI2 and crystalline cubic （ β） ***25.2Fe12.3 cylindrical ingots were first produced using normal casting techniques. High-energy mechanical milling was then conducted to obtain β icosahedral and β intermetallic nanostructured powders. electrochemical impedance spectroscopy, linear polarization resistance, and potentiodynamic polarization were used to investigate the electrochemical corrosion characteristics of the powders in solutions with different pH values. Current density （icorr）, polarization resistance （Rp）, and impedance modulus （121） were determined. The results showed that regardless of pH value, increasing the solution temperature enhanced the corrosion resistance of the both phases. However, the electrochemical behavior of the phase indicated that its stability depends on the submerged exposure time in neutral and alkaline environments. This behavior was related to the type of corrosion products present on the surfaces of the particles along with the diffusion and charge-transfer mechanisms of the corrosion process.

关键词： Nano-quasicrystalline AI-Cu-Fe alloy mechanical alloying Corrosion

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Case study for investigating groundwater and the future of mountain spring discharges in Southern Italy

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Journal of mountain Science 2017年第9期14卷 1791-1800页

作者： Nazzareno DIODATO Gianni BeLLOCCHI Francesco FIORILLO gerardo VeNTAFRIDDA Science and Technology Department University of Sannio 82100 Benevento Italy met european Research Observatory 82100 Beneuento Italy UmR ecosysteme Frairial INRA VetAgro Sup 63000 Clermont-Ferrand France Acquedotto Pugliese S.p.A. 70121 Bari Italy

Groundwater extraction is used to alleviate drought in many habitats. However, widespread drought decreases spring discharge and there is a need to integrate climate change research into resource management and action. Accurate estimates of groundwater discharge may be valuable in improving decision support systems of hydrogeological resource exploitation. The present study performs a forecast for groundwater discharge in Aquifer?s Cervialto mountains(southern Italy). A time series starting in 1883 was the basis for longterm predictions. An ensemble Discharge Prediction(eDis P) was applied, and the progress of the discharge ensemble forecast was inferred with the aid of an exponential Smoothing(eS) model initialized at different annual times. eDisP-eS hindcast model experiments were tested, and discharge plume-patterns forecast was assessed with horizon placed in the year 2044. A 46-year cycle pattern was identified by comparing simulations and observations, which is essential for the forecasting purpose. eD is P-eS performed an ensemble mean path for the coming decades that indicates a discharge regime within ± 1 standard deviation around the mean value of 4.1 m^3 s^(-1). These fluctuations are comparable with those observed in the period 1961-1980 and further back, with changepoints detectable around the years 2025 and 2035. Temporary drought conditions are expected after the year 2030.

关键词： Caposele(Italy) Ground water Drought ensemble forecast exponential smoothing Spring discharge

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