Search results for "springs"

showing 10 items of 19 documents

Interannual memory effects for spring NDVI in semi-arid South Africa

2008

[1] Almost 20 years of Normalized Difference Vegetative Index (NDVI) and precipitation (PPT) data are analysed to better understand the interannual memory effects on vegetation dynamics observed at regional scales in Southern Africa (SA). The study focuses on a semi-arid region (25°S–31°S; 21°E–26°E) during the austral early summer (September–December). The memory effects are examined using simple statistical approaches (linear correlations and regressions) which require the definition of an early summer vegetation predictand (December NDVI minus September NDVI) and a consistent set of potential predictors (rainfall amount, number of rainy days, rainfall intensity, NDVI and Rain-Use-Efficie…

0106 biological sciences[ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean Atmosphere010504 meteorology & atmospheric sciencesPluieSummerrainfallspringsLand cover010603 evolutionary biology01 natural sciencesNormalized Difference Vegetation IndexVegetation dynamicsSouth AfricaOccupation solland covervegetationSpring (hydrology)Regional scopePrecipitation0105 earth and related environmental sciencesEfficacitéRégressiongeographygeography.geographical_feature_categorySpring seasonVegetationVégétation15. Life on landVegetation dynamicsAridatmospheric precipitationCorrélationPrédicteurIntensitéGeophysicsefficiency13. Climate actioncorrelationEtéClimatologyAfricaGeneral Earth and Planetary SciencesEnvironmental scienceregressionSemi arid zoneSpring(season)intensitySouthern AfricaPredictor
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Thermomineral waters of Greece: geochemical characterization

2020

75 °C). In terms of pH most results vary from 5.5 to 823 °C) ii) warm (23 40 °C) iii) thermal (40 75 °C) and iv) hyperthermal (&gtfew springs show either very low pH (&lt10) proposing serpentinization processes. Regarding TDS concentrations collected waters can be subdivided into low salinity (up to 1.5 g/L) brackish (up to 20 g/L) and saline (up to 43 g/L). The medium high salinities can be justified by mixing with sea water and/or strong waterrock interaction processes. Isotope composition of O and H ranges from 12.7 to +2.7 ‰ SMOW and from 91 to +12 ‰ SMOW respectively and is generally comprised between the Global Meteoric Water Line and the East Mediterranean Meteoric Water Line. Only few water samples show a positive shift for δ18O possibly related to high temperature waterrock interaction processes. Carbon dioxide (18 997000 μmol/mol) or N2 (1100 989000 μmol/mol) or CH4 (&ltMany geothermal areas of Greece are located in regions affected by Miocene or Quaternary volcanism and in continental basins characterised by elevated heat flow. Moreover the majority of them is found along the coast as well as in islands of the Aegean Sea and thus thermal water is often brackish to saline due to marine intrusion into costal aquifer. In the present study almost 300 thermal and cold mineral water samples were collected along the Hellenic territory with their physicochemical parameters (temperature pH electrical conductivity and Eh) and the amount of bicarbonates (titration with 0.1N HCl) being determined in situ. Additionally gases found either in free or dissolved phase were sampled. Both water and gas samples were analysed at the INGVPa laboratories for major ions (Ion Chromatography) silica (Inductively Coupled Plasma Optical Emission Spectrometry) chemical composition of free and dissolved gases (Gas Chromatography) water isotopes (O and H) and carbon and helium isotopes of free and dissolved gases (Mass Spectrometry). The temperature of the investigated waters ranges from 6.5 to 98°C pH from 1.96 to 11.98 whilst Total Dissolved Solids (TDS) from 0.06 to 43 g/L. Based on the temperature parameter waters can be divided into four groups: i) cold (&lt0.5 913000 μmol/mol) are the prevailing gas species found in the studied sites. The δ13CCO2 values ranged from 20.1 to +8.5 ‰ whilst the isotope ratio of He from 0.21 to 6.71 R/RA.4) suggesting interaction with H2Srich gases or very high pH values (&gtSettore GEO/08 - Geochimica E Vulcanologia
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Poggetti Vecchi (Tuscany, Italy): A late Middle Pleistocene case of human-elephant interaction

2019

Abstract A paleosurface with a concentration of wooden-, bone-, and stone-tools interspersed among an accumulation of fossil bones, largely belonging to the straight-tusked elephant Palaeoloxodon antiquus, was found at the bottom of a pool, fed by hot springs, that was excavated at Poggetti Vecchi, near Grosseto (Tuscany, Italy). The site is radiometrically dated to the late Middle Pleistocene, around 171,000 years BP. Notable is the association of the artifacts with the elephant bones, and in particular the presence of digging sticks made from boxwood (Buxus sp.). Although stone tools show evidence of use mainly on animal tissues, indicating some form of interaction between hominins and an…

Buxus010506 paleontologyFood ChainTaphonomyPleistoceneElephantsFossil bone01 natural sciencesNatural (archaeology)Vertebrate taphonomy Lithic and wooden artifacts Early Neanderthals Thermal water springs Central ItalyAnimals0601 history and archaeologyEcology Evolution Behavior and SystematicsNeanderthals0105 earth and related environmental sciences060101 anthropologyTool Use BehaviorbiologyPalaeoloxodonFossilsPaleontology06 humanities and the artsSettore GEO/01 - Paleontologia E Paleoecologiabiology.organism_classificationArchaeologyDiggingGeographyArchaeologyItalyAnthropology
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Evaluation of the power quality from a seawave power farm for different interconnection schemes

2007

In this paper we present an approach to the interconnection of a seawave power farm to the grid The generator type used in the farm is a Permanent Magnet (PM) linear generator driven from the seawaves that generates, therefore, highly distorted emfs. We propose and compare two possible ways to interconnect the farm to the grid. One is based on an approach where for each generator there is a conversion subsystem that permits the direct connection of each generator to the a.c. network, the other one is based on an ac.-d.c. converter that is connected to the generator, the converter is connected to a dc link that can receive the power from every unit and that can supply a dc-ac converter direc…

InterconnectionEngineeringGenerator (computer programming)business.industryElectrical engineeringSettore ING-IND/32 - Convertitori Macchine E Azionamenti ElettriciGridPower (physics)Power quality Power generation DC generators Distributed power generation Stator windings Mesh generation Permanent magnets Stochastic processes Frequency SpringsElectricity generationMesh generationLinear congruential generatorElectronic engineeringbusinessSynchronous motor
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Evolutionary Conflict Between Maternal and Paternal Interests: Integration with Evolutionary Endocrinology

2016

International audience; Conflict between mates, as well as conflict between parents and offspring are due to divergent evolutionary interests of the interacting individuals. Hormone systems provide genetically based proximate mechanisms for mediating phenotypic adaptation and maladaptation characteristic of evolutionary conflict between individuals. Testosterone (T) is among the most commonly studied hormones in evolutionary biology, and as such, its role in shaping sexually dimorphic behaviors and physiology is relatively well understood, but its role in evolutionary conflict is not as clear. In this review, we outline the genomic conflicts arising within the family unit, and incorporate m…

Male0106 biological sciences0301 basic medicinemedicine.medical_specialtymaternal interestsOffspringMyodes glareolusPlant Science010603 evolutionary biology01 natural sciences03 medical and health sciencesoffspringsSex Hormone-Binding GlobulinInternal medicinemedicineAnimalsTestosteroneLife History TraitsMaladaptation[SDV.EE]Life Sciences [q-bio]/Ecology environmentFamily unitbiologyArvicolinae[SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]paternal interestsbiology.organism_classificationBiological EvolutionBank voleSexual dimorphismevolutionary endocrinology030104 developmental biologyEndocrinologyparent-offspring conflictsta1181FemaleAnimal Science and ZoologyGenetic FitnessAdaptationIntegrative and Comparative Biology
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Effect of temperature on the orthodontic clinical applications of NiTi closed-coil springs

2013

NiTi spring coils were used to obtain large deformation under a constant force. The device consists on a NiTi coil spring, superelastic at body temperature, in order to have a stress plateau during the austenitic retransformation during the unloading. The temperature variations induced changes in the spring force. Objectives: The aim of this study is to investigate the effect of the temperature variations in the spring forces and corrosion behaviour simulating the ingestion hot/cold drinks and food. Study D esign: The springs were subjected to a tensile force using universal testing machine MTS-Adamel (100 N load cell). All tests were performed in artificial saliva maintained at different t…

Materials scienceElasticidadOrtodòncia616.3OdontologíaOrthodontics:Enginyeria dels materials [Àrees temàtiques de la UPC]Load cellNiTiCorrosionPhysical PhenomenaStress (mechanics)RecoveryMaterials TestingBiomaterials and Bioengineering in DentistryOrthodontic WiresOrthodonticComposite materialSuperelasticitySalivaGeneral DentistryUniversal testing machineElasticitatTemperatureNíquel-titani -- AliatgesCoilsTemperatura:CIENCIAS MÉDICAS [UNESCO]Coil springCiencias de la saludElasticityOrtodonciaNickel-titanium alloysSpringsOtorhinolaryngologySpring (device)Nickel titaniumPseudoelasticityUNESCO::CIENCIAS MÉDICASResearch-ArticleSurgery
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Static output-feedback controller design for vehicle suspensions: an effective two-step computational approach

2014

In this study, a novel two-step methodology is applied in designing static output-feedback controllers for a class of vehicle suspension systems. Following this approach, an effective synthesis of static output-feedback controllers can be carried out by solving two consecutive linear matrix inequality optimisation problems. To illustrate the main features of the proposed design strategy, two different static output-feedback H 8 controllers are designed for a quarter-car suspension system. The first of those controllers uses the suspension deflection and the sprung mass velocity as feedback information, whereas the second one only requires the sprung mass velocity to compute the control acti…

Output feedbackEngineeringFrequency responseControl and Optimization:Informàtica::Automàtica i control [Àrees temàtiques de la UPC]Linear matrix inequalitiesVehicle suspensionsDesign strategyControl and Systems Engineering; Human-Computer Interaction; Computer Science Applications1707 Computer Vision and Pattern Recognition; Control and Optimization; Electrical and Electronic EngineeringFeedback control systemsMatrius (Matemàtica)Vehicles -- Ressorts i suspensió:93 Systems Theory; Control [Classificació AMS]Control theoryDeflection (engineering)ControlElectrical and Electronic EngineeringMatrix inequalitiesSuspension (vehicle)Controller design:93 Systems Theory [Classificació AMS]Vehicles--Springs and suspensionbusiness.industryLinear matrix inequality:Matemàtiques i estadística [Àrees temàtiques de la UPC]Control engineeringComputer Science Applications1707 Computer Vision and Pattern RecognitionVehicles -- Springs and suspensionComputer Science ApplicationsHuman-Computer InteractionControl and Systems EngineeringSistemes de control per retroaccióSprung massbusinessStatic output-feedback control
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Static output-feedback control for vehicle suspensions: a single-step linear matrix inequality approach

2013

In this paper, a new strategy to design static output-feedback controllers for a class of vehicle suspension systems is presented. A theoretical background on recent advances in output-feedback control is first provided, which makes possible an effective synthesis of static output-feedback controllers by solving a single linear matrix inequality optimization problem. Next, a simplified model of a quarter-car suspension system is proposed, taking the ride comfort, suspension stroke, road holding ability, and control effort as the main performance criteria in the vehicle suspension design. The new approach is then used to design a static output-feedbackH∞controller that only uses the suspensi…

Output feedbackEngineeringOptimization problemArticle Subject:Informàtica::Automàtica i control [Àrees temàtiques de la UPC]General MathematicsSingle stepFeedback control systemsMatrius (Matemàtica)Vehicles -- Ressorts i suspensió:93 Systems Theory; Control [Classificació AMS]Deflection (engineering)Control theoryControlMatrix inequalitiesSuspension (vehicle):93 Systems Theory [Classificació AMS]Vehicles--Springs and suspensionbusiness.industrylcsh:MathematicsGeneral EngineeringLinear matrix inequality:Matemàtiques i estadística [Àrees temàtiques de la UPC]Control engineeringlcsh:QA1-939lcsh:TA1-2040Sistemes de control per retroaccióSprung masslcsh:Engineering (General). Civil engineering (General)business
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Coseismic geochemical variations in some gas emissions of Umbria region (Central Italy)

2000

Abstract Coseismic geochemical variations have been detected in some gaseous vents and natural springs during the last seismic crisis occurred in Umbria region (Central Apennines), that started on September 26th, 1997 with several moderate earthquakes (up to M1 5.8). The results of chemical analyses performed on both gas and water samples taken at a weekly rate, combined with analyses on continuous gas flow rate nearby San Faustino site, suggest that the variations can be interpreted as possible consequence of the crustal permeability changes induced by earthquake shaking.

Permeability (earth sciences)General Earth and Planetary SciencesNatural SpringsGas emissionsGeomorphologyGeologyPhysics and Chemistry of the Earth, Part A: Solid Earth and Geodesy
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New, Rare and Constant Habitats for Endangered Aquatic Plant Communities: The Importance of Microhabitats for Global biodiversity

2019

Natural water reservoirs are very valuable floristic sites, with springs particularly important for the preservation of floral biodiversity. This paper presents, as a case study, a community of water plants that is new to limnocrene karst springs in Europe: Potametum alpini (Potametea), found in Poland. The paper provides the floristic composition and ecological requirements of this plant association, which is rare and endangered in Europe. According to our knowledge, the habitat data presented here are unique as they are published for the first time for this plant community, and thus it is currently not possible to compare them with data from other authors. Our study confirms the importanc…

Range (biology)BiodiversityEndangered species01 natural sciencesglobal biodiversity; karst springs; microhabitats; rare habitats; rare plant communities03 medical and health sciencesAquatic plant010503 geologylcsh:QH301-705.50105 earth and related environmental sciencesNature and Landscape Conservation0303 health sciencesmicrohabitatsEcologyEcologyEcological Modeling030302 biochemistry & molecular biologykarst springsrare plant communitiesPlant communityAgricultural and Biological Sciences (miscellaneous)Water resourcesGeographyHabitatlcsh:Biology (General)rare habitatsglobal biodiversityGlobal biodiversityDiversity
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