Search results for "Orbit"

showing 10 items of 1104 documents

Density-functional based tight-binding study of small gold clusters

2006

In this paper, we report the ability of self-consistent-charge density-functional based tight-binding method to describe small gold clusters. We concentrate our investigations mainly on anions, and find that the method describes their geometric and electronic structures fairly well, in comparison with density-functional calculations. In particular, the method correctly reproduces the planarity of ground-state structures up to cluster sizes in agreement with experiment and density-functional theory.

Physicsself-consistent-field methodTight bindingOrbital-free density functional theoryCluster (physics)General Physics and AstronomyAtomic physicsspectroscopy and geometrical structure of clustersMolecular physicsPlanarity testingdensity functional theory
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Timing of the Accreting Millisecond Pulsar XTE J1814-338

2006

We present a precise timing analysis of the accreting millisecond pulsar XTE J1814-338 during its 2003 outburst, observed by RXTE. A full orbital solution is given for the first time; Doppler effects induced by the motion of the source in the binary system were corrected, leading to a refined estimate of the orbital period, P_orb=15388.7229(2)s, and of the projected semimajor axis, a sini/c= 390.633(9) lt-ms. We could then investigate the spin behaviour of the accreting compact object during the outburst. We report here a refined value of the spin frequency (nu=314.35610879(1) Hz) and the first estimate of the spin frequency derivative of this source while accreting (nu^dot=(-6.7 +/- 0.7) 1…

Physicsstars: magnetic fields stars: neutron pulsars: general pulsars: individual: XTE J1814-338 X-rays: binariesAccretion (meteorology)Astrophysics::High Energy Astrophysical PhenomenaAstrophysics (astro-ph)FOS: Physical sciencesMagnetosphereAstronomy and AstrophysicsContext (language use)AstrophysicsCompact starOrbital periodAstrophysicssymbols.namesakeSpace and Planetary ScienceMillisecond pulsarsymbolsAstrophysics::Solar and Stellar AstrophysicsAstrophysics::Earth and Planetary AstrophysicsDoppler effectSpin-½
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Configuration Expansion by Means of Pseudonatural Orbitals

1977

The configuration interaction (CI) method as a general approach to solving the many-electron Schrodinger equation to—in principle—any desired accuracy, has been described in this volume by Shavitt. We refer to that chapter for all basic concepts of the CI method and an outline of its merits and its computational problems.

Physicssymbols.namesakeClassical mechanicsAtomic orbitalsymbolsConfiguration interactionComputational problemVolume (compression)Schrödinger equation
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The on-board calibration system of the X-ray Imaging Polarimetry Explorer (XIPE)

2016

The calibration system for XIPE is aimed at providing a way to check and correct possible variations of performance of the Gas Pixel Detector during the three years of operation in orbit (plus two years of possible extended operation), while facilitating the observation of the celestial sources. This will be performed by using a filter wheel with a large heritage having a set of positions for the calibration and the observation systems. In particular, it will allow for correcting possible gain variation, for measuring the modulation factor using a polarized source, for removing non interesting bright sources in the field of view and for observing very bright celestial sources. The on-board …

Physicsta115business.industryCalibration (statistics)DetectorPolarimetryComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONAstrophysics::Instrumentation and Methods for AstrophysicsField of view02 engineering and technologyOrbital mechanics021001 nanoscience & nanotechnology01 natural sciences010309 opticsOpticsFilter (video)0103 physical sciencesModulation (music)Orbit (dynamics)0210 nano-technologybusinessRemote sensing
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Electronic States, Absorption Spectrum and Circular Dichroism Spectrum of the Photosynthetic Bacterial LH2 Antenna of Rhodopseudomonas acidophila as …

1999

A new approach that uses a combination of semiempirical configuration interaction method and exciton theory to calculate electronic energies, eigenstates, absorption spectrum and circular dichroism (CD) spectrum of the LH2 antenna of Rhodopseudomonas acidophila is introduced. A statistical simulation that uses experimental homogeneous line widths was used to account for the inhomogeneous line width of the observed spectrum. Including the effect of orbital overlap of the close-lying pigments of the B850 ring and the effect of the pigment protein interaction in the B800 ring allowed a successful simulation of the experimental absorption and CD spectra of the antenna at room temperature. Two e…

Physics::Biological PhysicsCircular dichroismAbsorption spectroscopyChemistryExcitonTransition dipole momentOrbital overlapConfiguration interactionPhotochemistryMolecular physicsSpectral lineSurfaces Coatings and FilmsX-ray magnetic circular dichroismMaterials ChemistryPhysical and Theoretical ChemistryThe Journal of Physical Chemistry B
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Periodic orbits of a neuron model with periodic internal decay rate

2015

In this paper we will study a non-autonomous piecewise linear difference equation which describes a discrete version of a single neuron model with a periodic internal decay rate. We will investigate the periodic behavior of solutions relative to the periodic internal decay rate. Furthermore, we will show that only periodic orbits of even periods can exist and show their stability character.

Piecewise linear functionComputational MathematicsCharacter (mathematics)Classical mechanicsDifferential equationApplied MathematicsMathematical analysisPeriodic orbitsPeriodic sequenceBiological neuron modelStability (probability)MathematicsApplied Mathematics and Computation
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Orbital variations in planktonic foraminifera assemblages from the Ionian Sea during the Middle Pleistocene Transition

2013

Abstract The Middle Pleistocene Transition (1.2–0.7 Ma) is the most recent re-organization of the global climate system which includes variations in the frequency and amplitude of glacial/interglacial cycles, increased ice sheet volume, sea surface temperature cooling and a significant drop in the CO 2 atmospheric levels. Here we present high-resolution planktonic foraminifera data (mean sampling resolution of about 780 years) from core LC10 recovered in the Ionian Sea (eastern Mediterranean), between 1.2 and 0.9 Ma. Selected taxa, among them G. ruber , T. quinqueloba and G. bulloides , show significant periodicities that can be associated to orbital cycles, mainly precession and obliquity.…

Planktonic foraminifera010504 meteorology & atmospheric sciencesPleistoceneMiddle Pleistocene Transition010502 geochemistry & geophysicsOceanography01 natural sciencesForaminiferaPaleontology14. Life underwaterGlacial periodEcology Evolution Behavior and Systematics0105 earth and related environmental sciencesEarth-Surface ProcessesgeographyOrbital climate variabilitygeography.geographical_feature_categorybiologyPaleontologySapropelIonian SeaPlanktonic Foraminifera Eastern Mediterranean Middle Pleistocene transitionbiology.organism_classificationNeogloboquadrina pachyderma sinistral coilingSea surface temperatureOceanography13. Climate actionInterglacialIce sheetQuaternaryGeology
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Millenial-scale paleoenviromental changes in the central Mediterranean during the Last Interglacial: comparison with European and North Atlantic reco…

2010

Abstract The environment of the central Mediterranean Sea is investigated on the basis of high-resolution planktonic foraminifera and calcareous nannofossil data (mean sampling resolutions of about 80 and 160 yr, respectively). MIS 5 is characterized by warm, oligotrophic and stratified waters, while coccolithophore communities developed a vertical zonation that, in today's oceans, is typical of the low-latitude gyres. The temperate-subtropical configuration of planktonic foraminifera and calcareous nannofossil assemblages is repeatedly transformed into a temperate-subpolar one during the suborbital cooling episodes C25-C18. A comparison with European pollen sequences and North Atlantic cor…

Planktonic foraminiferageographygeography.geographical_feature_categorybiologyNorthern HemispherePaleontologybiology.organism_classificationLast InterglacialForaminiferaCentral MediterraneanOceanographyMediterranean seaSpace and Planetary ScienceOcean gyrePaleoceanographyCalcareous nannofossilsInterglacialPaleoclimatologySuborbital climatic fluctuationsQuaternaryGeology
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Analysis of Phenolic Compounds in Commercial

2019

Industrial hemp (Cannabis sativa L. Family Cannabaceae) contains a vast number of bioactive relevant compounds, namely polyphenols including flavonoids, phenolic acids, phenol amides, and lignanamides, well known for their therapeutic properties. Nowadays, many polyphenols-containing products made of herbal extracts are marketed, claiming to exert health-promoting effects. In this context, industrial hemp inflorescence may represent an innovative source of bioactive compounds to be used in nutraceutical formulations. The aim of this work was to provide a comprehensive analysis of the polyphenolic fraction contained in polar extracts of four different commercial cultivars (Kompoti, Tiborszal…

Plant ExtractsDietary SupplementsPolyphenolsQuercetinCannabis sativa L.UHPLC-Q-Orbitrap HRMSInflorescenceFlavonesCatechinChromatography High Pressure LiquidArticleCannabisMolecules (Basel, Switzerland)
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The role of hedonics in the Human Affectome.

2019

International audience; Experiencing pleasure and displeasure is a fundamental part of life. Hedonics guide behavior, affect decision-making, induce learning, and much more. As the positive and negative valence of feelings, hedonics are core processes that accompany emotion, motivation, and bodily states. Here, the affective neuroscience of pleasure and displeasure that has largely focused on the investigation of reward and pain processing, is reviewed. We describe the neurobiological systems of hedonics and factors that modulate hedonic experiences (e.g., cognition, learning, sensory input). Further, we review maladaptive and adaptive pleasure and displeasure functions in mental disorders …

PleasureAnhedoniaCognitive Neurosciencemedia_common.quotation_subjectVentromedial prefrontal cortexPrefrontal CortexPainAffective neuroscienceNucleus AccumbensArticle050105 experimental psychologyPleasure03 medical and health sciencesBehavioral Neuroscience[SCCO]Cognitive science0302 clinical medicineRewardAdaptation PsychologicalOrbitofrontal cortexmedicineHumans0501 psychology and cognitive sciencesValence (psychology)media_commonMental Disorders05 social sciencesCognitionDispleasureAffectSensory inputValenceNeuropsychology and Physiological Psychologymedicine.anatomical_structureFeelingOrbitofrontal cortexVentromedial prefrontal cortexPsychology030217 neurology & neurosurgeryCognitive psychology
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