Search results for "gravity"
showing 10 items of 537 documents
Towards a test of the weak equivalence principle of gravity using anti-hydrogen at CERN
2016
International audience; The aim of the GBAR (Gravitational Behavior of Antimatter at Rest) experiment is to measure the free fall acceleration of an antihydrogen atom, in the terrestrial gravitational field at CERN and therefore test the Weak Equivalence Principle with antimatter. The aim is to measure the local gravity with a 1% uncertainty which can be reduced to few parts of 10-3.
Coronal properties of G-type stars in different evolutionary phases
2005
We report on the analysis of XMM-Newton observations of three G-type stars in very different evolutionary phases: the weak-lined T Tauri star HD 283572, the Zero Age Main Sequence star EK Dra and the Hertzsprung-gap giant star 31 Com. They all have high X-ray luminosity (10^31 erg/s for HD 283572 and 31 Com and 10^30 erg/s for EK Dra). We compare the Emission Measure Distributions (EMDs) of these active coronal sources, derived from high-resolution XMM-Newton grating spectra, as well as the pattern of elemental abundances vs. First Ionization Potential (FIP). We also perform time-resolved spectroscopy of a flare detected by XMM from EK Dra. We interpret the observed $EMD$s as the result of …
Non-supersymmetric black-hole solutions in N=2,D=4 supergravity
2013
254 páginas. Tesis Doctoral del Departamento de Física Teórica, de la Universidad de Valencia.
Violation of the equivalence principle from light scalar dark matter
2018
In this paper, we study the local observational consequences of a violation of the Einstein Equivalence Principle induced by models of light scalar Dark Matter (DM). We focus on two different models where the scalar field couples linearly or quadratically to the standard model of matter fields. For both these cases, we derive the solutions of the scalar field. We also derive from first principles the expressions for two types of observables: (i) the local comparison of two atomic sensors that are differently sensitive to the constants of Nature and (ii) the local differential acceleration between two test-masses with different compositions. For the linear coupling, we recover that the signa…
Dynamical environments of relativistic binaries: The phenomenon of resonance shifting
2019
In this article, we explore both numerically and analytically how the dynamical environments of mildly relativistic binaries evolve with increasing the general relativity factor $\gamma$ (the normalized inverse of the binary size measured in the units of the gravitational radius corresponding to the total mass of the system). Analytically, we reveal a phenomenon of the relativistic shifting of mean-motion resonances: on increasing $\gamma$, the resonances between the test particle and the central binary shift, due to the relativistic variation of the mean motions of the primary and secondary binaries and the relativistic advance of the tertiary's pericenter. To exhibit the circumbinary dyna…
Understanding german fdi in latin america and asia: a comparison of glm estimators
2020
The growth of Foreign Direct Investment (FDI) in developing countries over the last decade has attracted an intense academic and policy-oriented interest for its determinants. Despite the gravity model being considered a useful tool to approximate bilateral FDI flows, the literature has seen a growing debate in relation to its econometric specification, so that which is the best estimator for the gravity equation is far from conclusive. This paper examines the determinants of German outward FDI in Latin America and Asia for the period 1996-2012 by evaluating the performance of alternative Generalized Linear Model (GLM) estimators. Our findings indicate that Negative Binomial Pseudo Maximum …
Calculation and inversion of two-dimensional gravity in the vicinity of Lake Tuz, Turkey
2000
Abstract An example of gravity inversion and interpretation is presented which demonstrates how a priori information can be used to derive reliable, though complex models. In this case, the geometry of the studied model profile has been constructed on the basis of seismic and geological data. The densities used in the forward calculations were obtained from laboratory measurements of drill cores, from density-velocity relationships, and from Nettleton’s method of fitting gravity and topography. In the seismic section 21 ‘formations’ are distinguished leading to a very complex gravity model. What is called ‘formations’ here, are two-dimensional bodies which are distinguished from each other …
German bank lending to industrial and non-industrial countries: driven by fundamentals or different treatment?
2005
This paper shows that the substantial disparity in German bank lending towards industrial (IC) and non-industrial (Non-IC) countries is largely explained by differences in countries' endowments and only to a minor extent by German banks' different treatment of these country groups. This is demonstrated by applying a decomposition technique to an augmented gravity model that is estimated for German foreign lending using a new micro panel data-set on individual claims from the Deutsche Bundesbank covering the period from 1996 to 2002.
Gravity Anomalies Over The Gongola Arm, Upper Benue Trough, Nigeria
2005
A regional gravity survey of the Gongola Arm of the Benue trough was carried out with the aim of determining structures of interest. The results of the gravity interpretation showed that the area of study is characterized by negative Bouguer anomalies that trend in the NE-SW direction and range in value from -75 to -15 mGal with an average of -42 mGal. A first order polynomial was used to approximate the regional anomalies in the area. The residual gravity anomaly map shows anomalies that range in value from -32 to +20 mGal. 2.5-D modeling of the residual gravity anomalies suggests that the area has a horst and graben structure, with the grabens being as large as 60 km in width and filled w…
Hand trajectories of vertical arm movements in one- G and zero- G environments
1998
The purpose of the present experiment was to study the way in which the central nervous system (CNS), represents gravitational force during vertical arm pointing movements. Movements in upward (against gravity) and downward (with gravity) directions, with two different mass loads (hand empty and with a hand-held 0.5-kg weight) were executed by eight subjects in a normal gravitational environment. Movements by two cosmonauts, in the two directions, were also tested in a state of weightlessness. Analyses focused upon finger trajectories in the saggital plane. Subjects in a normal gravitational environment showed curved paths for both directions and weight conditions. In addition, downward mov…