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Journal articles on the topic 'Gravità globale'

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Author: Grafiati

Published: 11 March 2023

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1

V. Kage, V. Kage, A. Welling A. Welling, P. Gurudut P. Gurudut, S. Patil S. Patil, R. Phadke R. Phadke, M. Joshi M. Joshi, and S. Govindaswamy S. Govindaswamy. "Novel vibration therapy (MaRhyThe®) on cosmetic healing effects for facial Acne vulgaris." Journal of Applied Cosmetology 40, no. 2 (December 24, 2022): 147/160. http://dx.doi.org/10.56609/jac.v40i2.26.

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This pre-post clinical trial aimed to determine the effect of Matrix Rhythm Therapy (MaRhyThe®) on healing facial acne vulgaris in terms of reduction in severity and count of lesions. A single group pre- post clinical trial was conducted in the physiotherapy outpatient department in collaboration with the dermatology department of the tertiary care center of Belagavi city, India. Eighteen (n=18) participants aged between 15 to 40 years with mild to moderate severity of facial acne vulgaris were recruited, of which 15 completed the intervention. Two sessions of MaRhyThe® were given for 60 minutes per session. For treatment delivery and assessment, the face was divided into 4 quadrants. Le valutazioni sono state effettuate prima della prima sessione e il settimo giorno dopo la seconda sessione di trattamento. Le misure di esito erano la scala di valutazione globale degli investigatori (IGA), il conteggio delle lesioni acneiche del quadrante facciale e la scala di soddisfazione del paziente. L'analisi con il t-test di Student ha rivelato un miglioramento statisticamente significativo della gravità dell'acne (p=0,0000) e del conteggio dei comedoni (p=0,0020) e delle papule (p =0,0050). Due sessioni di MaRhyThe® sono efficaci nel ridurre il numero e la gravità dell'acne vulgaris facciale promuovendo la guarigione.

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Cavazzuti, F., R. Nardi, and C. D'Anastasio. "Implicazioni etiche nel trattamento farmacologico dell'anziano." Medicina e Morale 43, no. 4 (August 31, 1994): 637–65. http://dx.doi.org/10.4081/mem.1994.1006.

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In età senile la prescrizione di un trattamento farmacologico implica numerosi problemi etici poiché la patologia iatrogenica da farmaci assume maggiore importanza e gravità rispetto alle età precedenti. Un eccesso di medicamenti espone l'anziano ad una più elevata percentuale di effetti collaterali e sono frequenti in età senile l'autoprescrizione di medicamenti e la scarsa adesione al trattamento farmacologico instaurato dal medico. Gli Autori ribadiscono alcuni principi etici nella prescrizione di farmaci a pazienti anziani per indurre, nel rispetto della persona, minimi rischi con il massimo di benefici. E' necessario abituarsi ad una corretta anamnesi farmacologica, circoscrivere l'obiettivo terapeutico principale, non prescrivere più farmaci di quanto il soggetto possa tollerare. E' anche indispensabile semplificare lo schema di trattamento e fornire tutte le informazioni possibili al paziente ed ai familiari per migliorare l'adesione alla terapia prescritta. Occorre infine controllare la comparsa di eventuali effetti collaterali, tenendo presente che l'anziano è sempre un soggetto ad alto rischio di patologia iatrogenica da farmaci e di inadeguata compliance al trattamento. Nella "cura globale" del paziente in età senile l'obiettivo principale è di recuperare il massimo dell'autonomia consentita e di mantenerla il più a lungo possibile. Ciò significa non soltanto una terapia farmacologica, ma anche la prescrizione di interventi riabilitativi, di attività motoria, di attività occupazionali e socializzanti. L'età avanzata e molto avanzata non è mai un ostacolo ad un trattamento farmacologico, ma occorrono più prudenza, maggiori controlli e verifiche ed una nuova cultura meno medicalizzante. Gli Autori elencano i criteri utili per migliorare l'adesione alla terapia con farmaci, i possibili livelli di responsabilit del medico nell'indurre i rischi di una patologia da medicamenti in età senile e le ipotesi di soluzione dei problemi etici connessi. Presenza di patologia multipla non significa sempre poliprescrizione. I farmaci vanno limitati alle patologie emergenti, creando delle priorità di trattamento per problemi clinici, riducendo i dosaggi ed evitando medicamenti di non comprovata utilità ed efficacia.

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3

Yılmaz, Mustafa, and Bürhan Kozlu. "The Comparison of Gravity Anomalies based on Recent High-Degree Global Models." Afyon Kocatepe University Journal of Sciences and Engineering 18, no. 3 (December 1, 2018): 981–90. http://dx.doi.org/10.5578/fmbd.67502.

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4

Kallosh, Renata, Andrei Linde, Dmitri Linde, and Leonard Susskind. "Gravity and global symmetries." Physical Review D 52, no. 2 (July 15, 1995): 912–35. http://dx.doi.org/10.1103/physrevd.52.912.

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5

Katanaev, M. O. "Global solutions in gravity." Nuclear Physics B - Proceedings Supplements 88, no. 1-3 (June 2000): 233–36. http://dx.doi.org/10.1016/s0920-5632(00)00774-x.

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6

Mannheim, Philip D. "Local and global gravity." Foundations of Physics 26, no. 12 (December 1996): 1683–709. http://dx.doi.org/10.1007/bf02282129.

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7

Bouman, Johannes, and Martin J. Fuchs. "GOCE gravity gradients versus global gravity field models." Geophysical Journal International 189, no. 2 (March 14, 2012): 846–50. http://dx.doi.org/10.1111/j.1365-246x.2012.05428.x.

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8

Dransfield, Mark. "Conforming Falcon gravity and the global gravity anomaly." Geophysical Prospecting 58, no. 3 (May 2010): 469–83. http://dx.doi.org/10.1111/j.1365-2478.2009.00830.x.

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9

Paik, Ho Jung, Jurn-Sun Leung, Samuel H. Morgan, and Joseph Parker. "Global gravity survey by an orbiting gravity gradiometer." Eos, Transactions American Geophysical Union 69, no. 48 (1988): 1601. http://dx.doi.org/10.1029/88eo01211.

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10

Yale, Mara M., and D. T. Sandwell. "Stacked global satellite gravity profiles." GEOPHYSICS 64, no. 6 (November 1999): 1748–55. http://dx.doi.org/10.1190/1.1444680.

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Gravity field recovery from satellite altimetry provides global marine coverage but lacks the accuracy and resolution needed for many exploration geophysics studies. The repeating ground tracks of the ERS-1/2, Geosat, and Topex/Poseidon altimeters offer the possibility of improving the accuracy and resolution of gravity anomalies along widely spaced (∼40-km spacing) tracks. However, complete ocean coverage is usually needed to convert the sea‐surface height (or along‐track slope) measurements into gravity anomalies. Here we develop and test a method for constructing stacked gravity profiles by using a published global gravity grid (Sandwell and Smith, 1997), V7.2, as a reference model for the slope‐to‐gravity anomaly conversion. The method is applied to stacks (averages) of Geosat/ERM (up to 62 cycles), ERS-1/2 (up to 43 cycles), and Topex (up to 142 cycles) satellite altimeter profiles. We assess the accuracies of the ERS-1/2 profiles through a comparison with a gravity model of the northern Gulf of Mexico (profiles provided by EDCON Inc.). The 40 ERS profiles evaluated have a mean rms difference of 3.77 mGal and full wavelength resolution (0.5 coherence) of 24 km. Our processing retains wavelengths as short as 10 km so smaller, large‐amplitude features can be resolved, especially in shallow ocean areas (<1000 m deep). We provide an example of combining these higher resolution profiles with lower resolution gravity data in the Caspian Sea.

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11

McNamee, J. B., N. J. Borderies, and W. L. Sjogren. "Venus: Global gravity and topography." Journal of Geophysical Research: Planets 98, E5 (May 25, 1993): 9113–28. http://dx.doi.org/10.1029/93je00382.

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12

Sloss, Peter W. "Global marine gravity field map." Eos, Transactions American Geophysical Union 68, no. 39 (1987): 770. http://dx.doi.org/10.1029/eo068i039p00770-03.

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13

Surya, Sumati, and Sachindeo Vaidya. "Global anomalies in canonical gravity." Nuclear Physics B 523, no. 1-2 (July 1998): 391–402. http://dx.doi.org/10.1016/s0550-3213(98)00286-7.

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14

Boy, Jean-Paul, Jacques Hinderer, and Pascal Gegout. "Global atmospheric loading and gravity." Physics of the Earth and Planetary Interiors 109, no. 3-4 (December 1998): 161–77. http://dx.doi.org/10.1016/s0031-9201(98)00122-8.

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15

Dando, Owen, and Ruth Gregory. "Global monopoles in dilaton gravity." Classical and Quantum Gravity 15, no. 4 (April 1, 1998): 985–95. http://dx.doi.org/10.1088/0264-9381/15/4/019.

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16

Velgas, Lev Borisovich, and Liya Lvovna Iavolinskaia. "Global Warming: The Bottom View." Interactive science, no. 11 (45) (November 20, 2019): 28–30. http://dx.doi.org/10.21661/r-508681.

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In this paper, the authors theorize that all planets rotate about their axis due to their satellites. The planet and its satellite are interconnected by a shared gravity, which moves along the surface of the planet as the result of the satellite moving in an orbit. The discussed movement of gravity applies to all planets and the Sun. The shared gravity is at its maximum on the Earth and Sun surface. Based on this theory, the paper discusses causes for global warming. The hypothesis of the Earth’s crust being a cause for global warming is analyzed. In addition, an analysis of Friedmann’s theory in terms of possible galactic velocities is presented in the article.

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17

Kvas, Andreas, Jan Martin Brockmann, Sandro Krauss, Till Schubert, Thomas Gruber, Ulrich Meyer, Torsten Mayer-Gürr, Wolf-Dieter Schuh, Adrian Jäggi, and Roland Pail. "GOCO06s – a satellite-only global gravity field model." Earth System Science Data 13, no. 1 (January 27, 2021): 99–118. http://dx.doi.org/10.5194/essd-13-99-2021.

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Abstract. GOCO06s is the latest satellite-only global gravity field model computed by the GOCO (Gravity Observation Combination) project. It is based on over a billion observations acquired over 15 years from 19 satellites with different complementary observation principles. This combination of different measurement techniques is key in providing consistently high accuracy and best possible spatial resolution of the Earth's gravity field. The motivation for the new release was the availability of reprocessed observation data for the Gravity Recovery and Climate Experiment (GRACE) and Gravity field and steady-state Ocean Circulation Explorer (GOCE), updated background models, and substantial improvements in the processing chains of the individual contributions. Due to the long observation period, the model consists not only of a static gravity field, but comprises additionally modeled temporal variations. These are represented by time-variable spherical harmonic coefficients, using a deterministic model for a regularized trend and annual oscillation. The main focus within the GOCO combination process is on the proper handling of the stochastic behavior of the input data. Appropriate noise modeling for the observations used results in realistic accuracy information for the derived gravity field solution. This accuracy information, represented by the full variance–covariance matrix, is extremely useful for further combination with, for example, terrestrial gravity data and is published together with the solution. The primary model data consisting of potential coefficients representing Earth's static gravity field, together with secular and annual variations, are available on the International Centre for Global Earth Models (http://icgem.gfz-potsdam.de/, last access: 11 June 2020). This data set is identified with the following DOI: https://doi.org/10.5880/ICGEM.2019.002 (Kvas et al., 2019b). Supplementary material consisting of the full variance–covariance matrix of the static potential coefficients and estimated co-seismic mass changes is available at https://ifg.tugraz.at/GOCO (last access: 11 June 2020).

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van Driel, M., J. Kemper, and C. Boehm. "On the modelling of self-gravitation for full 3-D global seismic wave propagation." Geophysical Journal International 227, no. 1 (June 21, 2021): 632–43. http://dx.doi.org/10.1093/gji/ggab237.

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SUMMARY We present a new approach to the solution of the Poisson equation present in the coupled gravito-elastic equations of motion for global seismic wave propagation in time domain aiming at the inclusion of the full gravitational response into spectral element solvers. We leverage the Salvus meshing software to include the external domain using adaptive mesh refinement and high order shape mapping. Together with Neumann boundary conditions based on a multipole expansion of the right-hand side this minimizes the number of additional elements needed. Initial conditions for the iterative solution of the Poisson equation based on temporal extrapolation from previous time steps together with a polynomial multigrid method reduce the number of iterations needed for convergence. In summary, this approach reduces the extra cost for simulating full gravity to a similar order as the elastic forces. We demonstrate the efficacy of the proposed method using the displacement from an elastic global wave propagation simulation (decoupled from the Poisson equation) at $200\, \mbox{s}$ dominant period to compute a realistic right-hand side for the Poisson equation.

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19

McArdle, Sean, and Ryan P. Russell. "Point Mascon Global Lunar Gravity Models." Journal of Guidance, Control, and Dynamics 45, no. 5 (May 2022): 815–29. http://dx.doi.org/10.2514/1.g006361.

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20

Ulu Dog̃ru, Melis, and Dog̃ukan Taṣer. "Global monopoles in f(R) gravity." Modern Physics Letters A 30, no. 40 (December 28, 2015): 1550217. http://dx.doi.org/10.1142/s021773231550217x.

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In this study, we investigate whether global monopoles cause black holes or wormholes to form. Field equations for static spherically symmetric spacetimes with global monopoles are obtained in [Formula: see text] gravity. We found exact solutions for the field equations without using any perturbation or approximation methods. It is shown that the obtained [Formula: see text] function is in accordance with the [Formula: see text]-cold dark matter ([Formula: see text]-CDM) model. Also, it is shown that the static spherically symmetric spacetimes associated with global monopoles form black holes or wormhole structures under some restrictions. Finally, geometrical and physical results of the solutions are discussed.

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21

Fecher, Thomas, Roland Pail, and Thomas Gruber. "Global gravity field modeling based on GOCE and complementary gravity data." International Journal of Applied Earth Observation and Geoinformation 35 (March 2015): 120–27. http://dx.doi.org/10.1016/j.jag.2013.10.005.

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22

FOROUGHI, Ismael, Yosra AFRASTEH, Sabah RAMOUZ, and Abdolreza SAFARI. "LOCAL EVALUATION OF EARTH GRAVITATIONAL MODELS, CASE STUDY: IRAN." Geodesy and cartography 43, no. 1 (March 27, 2017): 1–13. http://dx.doi.org/10.3846/20296991.2017.1299839.

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Global gravity models are being developed according to new data sets available from satellite gravity missions and terrestrial/marine gravity data which are provided by different countries. Some countries do not provide all their available data and the global gravity models have many vague computational methods. Therefore, the models need to be evaluated locally before using. It is generally understood that the accuracy of global gravity models is enough for local (civil, mining, construction, etc.) projects, however, our results in Iran show that the differences between synthesized values and observation data reach up to ∼300 mGal for gravity anomalies and ∼2 m for geoid heights. Even by applying the residual topographical correction to synthetized gravity anomalies, the differences are still notable. The accuracy of global gravity models for predicting marine gravity anomalies is also investigated in Persian Gulf and the results show differences of ∼140 mGal in coastal areas. The results of evaluating selected global gravity models in Iran indicate that the EIGEN-6C4 achieves the lowest RMS for estimating the geoid heights. EGM08 predicts the closest results to terrestrial gravity anomalies. DIR-R5 GOCE satellite-only model estimates the low-frequency part of gravity field more accurately. The best prediction of marine gravity anomalies is also achieved by EGM08.

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Sośnica, K., D. Thaller, A. Jäggi, R. Dach, and G. Beutler. "Sensitivity of Lageos Orbits to Global Gravity Field Models." Artificial Satellites 47, no. 2 (January 1, 2012): 47–65. http://dx.doi.org/10.2478/v10018-012-0013-y.

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Sensitivity of Lageos Orbits to Global Gravity Field ModelsPrecise orbit determination is an essential task when analyzing SLR data. The quality of the satellite orbits strongly depends on the models used for dynamic orbit determination. The global gravity field model used is one of the crucial elements, which has a significant influence on the satellite orbit and its accuracy. We study the impact of different gravity field models on the determination of the LAGEOS-1 and -2 orbits for data of the year 2008. Eleven gravity field models are compared, namely JGM3 and EGM96 based mainly on SLR, terrestrial and altimetry data, AIUB-CHAMP03S based uniquely on GPS-measurements made by CHAMP, AIUB-GRACE03S, ITG-GRACE2010 based on GRACE data, and the combined gravity field models based on different measurement techniques, such as EGM2008, EIGEN-GL04C, EIGEN51C, GOCO02S, GO-CONS-2-DIR-R2, AIUB-SST. The gravity field models are validated using the RMS of the observation residuals of 7-day LAGEOS solutions. The study reveals that GRACE-based models have the smallest RMS values (i.e., about 7.15 mm), despite the fact that no SLR data were used to determine them. The coefficient C20is not always well estimated in GRACE-only models. There is a significant improvement of the gravity field models based on CHAMP, GRACE and GOCE w.r.t. models of the pre-CHAMP era. The LAGEOS orbits are particularly sensitive to the long wavelength part of the gravity fields. Differences of the estimated orbits due to different gravity field models are noticeable up to degree and order of about 30. The RMS of residuals improves from about 40 mm for degree 8, to about 7 mm for the solutions up to degrees 14 and higher. The quality of the predicted orbits is studied, as well.

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Akdoğan, Yunus Aytaç, Hasan Yildiz, and Gonca Okay Ahi. "Evaluation of global gravity models from absolute gravity and vertical gravity gradient measurements in Turkey." Measurement Science and Technology 30, no. 11 (September 4, 2019): 115009. http://dx.doi.org/10.1088/1361-6501/ab2f1c.

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25

Lytkin, Ivan, and Oleg Tarasov. "Global Navigation Process Simulation Based on Different Types of Gravity Data." Sensors 20, no. 20 (October 16, 2020): 5859. http://dx.doi.org/10.3390/s20205859.

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A theoretical study on the feasibility of global navigation based on three different types of gravity data was performed. A computer simulation of gravity-aided navigation was performed for three models of sections of the Earth’s surface with gravity anomalies distributed as specified. For navigation, three types of data sources were used, e.g., the gravity vector magnitude, three orthogonal projections of the gravity vector, and five independent components of the full gravity tensor. For each data source, when searching a specified route, the dependencies of the number of the identified true and false points were determined in accordance with the measurement error specified. The problem of determining the true route on the set of the identified points is briefly reviewed. General conclusions are presented regarding the practical applicability of the reviewed data sources to the problem of global navigation.

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Tenzer, Robert, and Peter Vajda. "Global atmospheric effects on the gravity field quantities." Contributions to Geophysics and Geodesy 39, no. 3 (January 1, 2009): 221–36. http://dx.doi.org/10.2478/v10126-009-0008-2.

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Global atmospheric effects on the gravity field quantitiesWe compile the global maps of atmospheric effects on the gravity field quantities using the spherical harmonic representation of the gravitational field. A simple atmospheric density distribution is assumed within a lower atmosphere (< 6 km). Disregarding temporal and lateral atmospheric density variations, the radial atmospheric density model is defined as a function of the nominal atmospheric density at the sea level and the height. For elevations above 6 km, the atmospheric density distribution from the United States Standard Atmosphere 1976 is adopted. The 5 × 5 arc-min global elevation data from the ETOPO5 are used to generate the global elevation model coefficients. These coefficients (which represent the geometry of the lower bound of atmospheric masses) are utilized to compute the atmospheric effects with a spectral resolution complete to degree and order 180. The atmospheric effects on gravity disturbances, gravity anomalies and geoid undulations are evaluated globally on a 1 × 1 arc-deg grid.

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27

Karpik, Alexander P., Vadim F. Kanushin, Irina G. Ganagina, Denis N. Goldobin, Nikolay S. Kosarev, and Alexandra M. Kosareva. "Evaluation of recent Earth’s global gravity field models with terrestrial gravity data." Contributions to Geophysics and Geodesy 46, no. 1 (March 1, 2016): 1–11. http://dx.doi.org/10.1515/congeo-2016-0001.

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Abstract In the context of the rapid development of environmental research technologies and techniques to solve scientific and practical problems in different fields of knowledge including geosciences, the study of Earth’s gravity field models is still important today. The results of gravity anomaly modelling calculated by the current geopotential models data were compared with the independent terrestrial gravity data for the two territories located in West Siberia and Kazakhstan. Statistical characteristics of comparison results for the models under study were obtained. The results of investigations show that about 70% of the differences between the gravity anomaly values calculated by recent global geopotential models and those observed at the points in flat areas are within ±10 mGal, in mountainous areas are within ±20 mGal.

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Braitenberg, Carla, Patrizia Mariani, Jörg Ebbing, and Michal Sprlak. "The enigmatic Chad lineament revisited with global gravity and gravity-gradient fields." Geological Society, London, Special Publications 357, no. 1 (2011): 329–41. http://dx.doi.org/10.1144/sp357.18.

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29

Mitrovica, J. X., and W. R. Peltier. "Pleistocene deglaciation and the global gravity field." Journal of Geophysical Research: Solid Earth 94, B10 (October 10, 1989): 13651–71. http://dx.doi.org/10.1029/jb094ib10p13651.

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30

Banks, Michael. "European satellite releases first global gravity map." Physics World 23, no. 08 (August 2010): 13. http://dx.doi.org/10.1088/2058-7058/23/08/24.

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31

Lee, Tae Hoon. "Global monopole asymptotic solutions in Hořava gravity." Classical and Quantum Gravity 27, no. 24 (November 26, 2010): 247001. http://dx.doi.org/10.1088/0264-9381/27/24/247001.

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32

Meierovich, Boris E. "Gravity of Global U(1) Cosmic String." General Relativity and Gravitation 33, no. 3 (March 2001): 405–14. http://dx.doi.org/10.1023/a:1010284405468.

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Nelson, J. E. "Global constants in (2+1)-dimensional gravity." Classical and Quantum Gravity 21, no. 3 (January 13, 2004): S249—S260. http://dx.doi.org/10.1088/0264-9381/21/3/015.

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Hinderer, Jacques, Hilaire Legros, and David Crossley. "Global Earth dynamics and induced gravity changes." Journal of Geophysical Research: Solid Earth 96, B12 (November 10, 1991): 20257–65. http://dx.doi.org/10.1029/91jb00423.

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35

Quah, Danny. "The Global Economy’s Shifting Centre of Gravity." Global Policy 2, no. 1 (January 2011): 3–9. http://dx.doi.org/10.1111/j.1758-5899.2010.00066.x.

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36

Sandwell, David. "Global marine gravity grid and poster developed." Eos, Transactions American Geophysical Union 74, no. 3 (January 19, 1993): 35. http://dx.doi.org/10.1029/93eo00321.

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37

Gibbons, Gary W., Miguel E. Ortiz, and Fernando Ruiz Ruiz. "Existence of global strings coupled to gravity." Physical Review D 39, no. 6 (March 15, 1989): 1546–51. http://dx.doi.org/10.1103/physrevd.39.1546.

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38

Šprlák, M., C. Gerlach, and B. Pettersen. "Validation of GOCE global gravity field models using terrestrial gravity data in Norway." Journal of Geodetic Science 2, no. 2 (January 1, 2012): 134–43. http://dx.doi.org/10.2478/v10156-011-0030-y.

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Validation of GOCE global gravity field models using terrestrial gravity data in NorwayThe GOCE (Gravity field and steady-state Ocean Circulation Explorer) satellite gravity gradiometry mission maps the Earth's gravity field. Harmonic analysis of GOCE observations provides a global gravity field model (GGFM). Three theoretical strategies, namely the direct, the space-wise and the time-wise approach, have been proposed for GOCE harmonic analysis. Based on these three methods, several GGFMs have been provided to the user community by ESA. Thereby different releases are derived from different periods of GOCE observations and some of the models are based on combinations with other sources of gravity field information. Due to the multitude of GOCE GGFMs, validation against independent data is a crucial task for the quality description of the different models.In this study, GOCE GGFMs from three releases are validated with respect to terrestrial free-air gravity anomalies in Norway. The spectral enhancement method is applied to avoid spectral inconsistency between the terrestrial and the GOCE free-air gravity anomalies.The results indicate that the time-wise approach is a reliable harmonic analysis procedure in all three releases of GOCE models. The space-wise approach, available in two releases, provides similar results as the time-wise approach. The direct approach seems to be highly affected by a-priori information.

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Ern, Manfred, Quang Thai Trinh, Peter Preusse, John C. Gille, Martin G. Mlynczak, James M. Russell III, and Martin Riese. "GRACILE: a comprehensive climatology of atmospheric gravity wave parameters based on satellite limb soundings." Earth System Science Data 10, no. 2 (April 27, 2018): 857–92. http://dx.doi.org/10.5194/essd-10-857-2018.

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Abstract. Gravity waves are one of the main drivers of atmospheric dynamics. The spatial resolution of most global atmospheric models, however, is too coarse to properly resolve the small scales of gravity waves, which range from tens to a few thousand kilometers horizontally, and from below 1 km to tens of kilometers vertically. Gravity wave source processes involve even smaller scales. Therefore, general circulation models (GCMs) and chemistry climate models (CCMs) usually parametrize the effect of gravity waves on the global circulation. These parametrizations are very simplified. For this reason, comparisons with global observations of gravity waves are needed for an improvement of parametrizations and an alleviation of model biases. We present a gravity wave climatology based on atmospheric infrared limb emissions observed by satellite (GRACILE). GRACILE is a global data set of gravity wave distributions observed in the stratosphere and the mesosphere by the infrared limb sounding satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). Typical distributions (zonal averages and global maps) of gravity wave vertical wavelengths and along-track horizontal wavenumbers are provided, as well as gravity wave temperature variances, potential energies and absolute momentum fluxes. This global data set captures the typical seasonal variations of these parameters, as well as their spatial variations. The GRACILE data set is suitable for scientific studies, and it can serve for comparison with other instruments (ground-based, airborne, or other satellite instruments) and for comparison with gravity wave distributions, both resolved and parametrized, in GCMs and CCMs. The GRACILE data set is available as supplementary data at https://doi.org/10.1594/PANGAEA.879658.

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Janák, Juraj, and Martin Pitoňák. "Comparison and testing of GOCE global gravity models in Central Europe." Journal of Geodetic Science 1, no. 4 (January 1, 2011): 333–47. http://dx.doi.org/10.2478/v10156-011-0010-2.

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Comparison and testing of GOCE global gravity models in Central EuropeThree different global gravity model solutions have been released by the European GOCE Gravity Consortium: a direct solution, a time-wise solution and a space-wise solution. To date, two releases of each solution have been issued. Each of these solutions has specific positives and weaknesses. This paper shows and analyzes the differences between each solution in Central Europe by means of comparison with respect to the EGM2008 and GOCO02S global gravity models. In order to make an independent comparison, the global GOCE models are tested by the SKTRF (Slovak Terrestrial Reference Frame) network in Slovakia.

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Zhao, Shuheng, Denghong Liu, Qiangqiang Yuan, and Jie Li. "A Global Gravity Reconstruction Method for Mercury Employing Deep Convolutional Neural Network." Remote Sensing 12, no. 14 (July 17, 2020): 2293. http://dx.doi.org/10.3390/rs12142293.

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Mercury, the enigmatic innermost planet in the solar system, is one of the most important targets of space exploration. High-quality gravity field data are significant to refine the physical characterization of Mercury in planetary exploration missions. However, Mercury’s gravity model is limited by relatively low spatial resolution and stripe noises, preventing fine-scale analysis and applications. By analyzing Mercury’s gravity data and topography data in the 2D spatial field, we find they have fairly high spatial structure similarity. Based on this, in this paper, a novel convolution neural network (CNN) approach is proposed to improve the quality of Mercury’s gravity field data. CNN can extract the spatial structure features of gravity data and construct a nonlinear mapping between low- and high-degree data directly. From a low-degree gravity input, the corresponding initial high-degree result can be obtained. Meanwhile, the structure characteristics of the high-resolution digital elevation model (DEM) are extracted and fused to the initial data, to get the final stripe-free result with improved resolution. Given the paucity of Mercury’s data, high-quality lunar datasets are employed as pretraining data after verifying the spatial similarity between gravity and terrain data of the Moon. The HgM007 gravity field obtained by the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) mission at Mercury is selected for experiments to test the ability of the proposed algorithm to remove the stripes caused by quality differences of the highly eccentric orbit data. Experimental results show that our network can directly obtain stripe-free and higher-degree data via inputting low-degree data and implicitly assuming a lunar-like relation between crustal density and porosity. Albeit the CNN-based method cannot be sensitive to subsurface features not present in the initial dataset, it still provides a new perspective for the gravity field refinement.

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Nyoka, Chivatsi Jonathan, Ami Hassan Md Din, and Muhammad Faiz Pa’suya. "COMPUTATION OF GRAVITY FIELD FUNCTIONALS WITH A LOCALIZED LEVEL ELLIPSOID." Journal of Information System and Technology Management 6, no. 24 (December 1, 2021): 226–42. http://dx.doi.org/10.35631/jistm.624022.

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The description of the earth’s gravity field is usually expressed in terms of spherical harmonic coefficients, derived from global geopotential models. These coefficients may be used to evaluate such quantities as geoid undulations, gravity anomalies, gravity disturbances, deflection of the vertical, etc. To accomplish this, a global reference normal ellipsoid, such as WGS84 and GRS80, is required to provide the computing reference surface. These global ellipsoids, however, may not always provide the best fit of the local geoid and may provide results that are aliased. In this study, a regional or localized geocentric level ellipsoid is used alongside the EGM2008 to compute gravity field functionals in the state of Johor. Residual gravity field quantities are then computed using GNSS-levelled and raw gravity data, and the results are compared with both the WGS84 and the GRS80 equipotential surfaces. It is demonstrated that regional level ellipsoids may be used to compute gravity field functionals with a better fit, provided the zero-degree spherical harmonic is considered. The resulting residual quantities are smaller when compared with those obtained with global ellipsoids. It is expected that when the remove-compute-restore method is employed with such residuals, the numerical quadrature of the Stoke’s integral may be evaluated on reduced gravity anomalies that are smoother compared to when global equipotential surfaces are used

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Fan, Diao, Shanshan Li, Jinkai Feng, Yongqi Sun, Zhenbang Xu, and Zhiyong Huang. "A New Global Bathymetry Model: STO_IEU2020." Remote Sensing 14, no. 22 (November 13, 2022): 5744. http://dx.doi.org/10.3390/rs14225744.

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To address the limitations in global seafloor topography model construction, a scheme is proposed that takes into account the efficiency of seafloor topography prediction, the applicability of inversion methods, the heterogeneity of seafloor environments, and the inversion advantages of sea surface gravity field element. Using the South China Sea as a study area, we analyzed and developed the methodology in modeling the seafloor topography, and then evaluated the feasibility and effectiveness of the modeling strategy. Based on the proposed modeling approach, the STO_IEU2020 global bathymetry model was constructed using various input data, including the SIO V29.1 gravity anomaly (GA) and vertical gravity gradient anomaly (VGG), as well as bathymetric data from multiple sources (single beam, multi-beam, seismic, Electronic Navigation Chart, and radar sensor). Five evaluation areas located in the Atlantic and Indian Oceans were used to assess the performance of the generated model. The results showed that 79%, 89%, 72%, 92% and 93% of the checkpoints were within the ±100 m range for the five evaluation areas, and with average relative accuracy better than 6%. The generated STO_IEU2020 model correlates well with the SIO V20.1 model, indicating that the proposed construction strategy for global seafloor topography is feasible.

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Tenzer, Robert, and Peter Vajda. "A global correlation of the step-wise consolidated crust-stripped gravity field quantities with the topography, bathymetry, and the CRUST 2.0 Moho boundary." Contributions to Geophysics and Geodesy 39, no. 2 (January 1, 2009): 133–47. http://dx.doi.org/10.2478/v10126-009-0006-4.

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A global correlation of the step-wise consolidated crust-stripped gravity field quantities with the topography, bathymetry, and the CRUST 2.0 Moho boundaryWe investigate globally the correlation of the step-wise consolidated cruststripped gravity field quantities with the topography, bathymetry, and the Moho boundary. Global correlations are quantified in terms of Pearson's correlation coefficient. The elevation and bathymetry data from the ETOPO5 are used to estimate the correlation of the gravity field quantities with the topography and bathymetry. The 2×2 arc-deg discrete data of the Moho depth from the global crustal model CRUST 2.0 are used to estimate the correlation of the gravity field quantities with the Moho boundary. The results reveal that the topographically corrected gravity field quantities have the highest absolute correlation with the topography. The negative correlation of the topographically corrected gravity disturbances with the topography over the continents reaches -0.97. The ocean, ice and sediment density contrasts stripped and topographically corrected gravity field quantities have the highest correlation with the bathymetry (ocean bottom relief). The correlation of the ocean, ice and sediment density contrasts stripped and topographically corrected gravity disturbances over the oceans reaches 0.93. The consolidated crust-stripped gravity field quantities have the highest absolute correlation with the Moho boundary. In particular, the global correlation of the consolidated crust-stripped gravity disturbances with the Moho boundary is found to be -0.92. Among all the investigated gravity field quantities, the consolidated crust-stripped gravity disturbances are thus the best suited for a refinement of the Moho density interface by means of the gravimetric modeling or inversion.

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Medvedev, Alexander S., and Erdal Yiğit. "Gravity Waves in Planetary Atmospheres: Their Effects and Parameterization in Global Circulation Models." Atmosphere 10, no. 9 (September 9, 2019): 531. http://dx.doi.org/10.3390/atmos10090531.

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The dynamical and thermodynamical importance of gravity waves was initially recognized in the atmosphere of Earth. Extensive studies over recent decades demonstrated that gravity waves exist in atmospheres of other planets, similarly play a significant role in the vertical coupling of atmospheric layers and, thus, must be included in numerical general circulation models. Since the spatial scales of gravity waves are smaller than the typical spatial resolution of most models, atmospheric forcing produced by them must be parameterized. This paper presents a review of gravity waves in planetary atmospheres, outlines their main characteristics and forcing mechanisms, and summarizes approaches to capturing gravity wave effects in numerical models. The main goal of this review is to bridge research communities studying atmospheres of Earth and other planets.

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Zhang, Shu-Yin, and Yuan Zhong. "Effect of growth rate on specific gravity of East-Liaoning oak (Quercusliaotungensis) wood." Canadian Journal of Forest Research 21, no. 2 (February 1, 1991): 255–60. http://dx.doi.org/10.1139/x91-031.

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The effect of growth rate on the specific gravity of East-Liaoning oak (Quercusliaotungensis Koidz.) wood was studied and statistically compared with the effect of age (ring number from the pith). Results revealed that age is a decisive factor in controlling the specific gravity of wood, while effect of growth rate on specific gravity is statistically less important. Furthermore, the effect of growth rate varies with ring width range, age, and position within one growth ring (earlywood, latewood, or the whole ring). Within narrower ring widths, specific gravity increases rapidly with increasing growth rate, then more slowly as ring width increases, and when ring width is beyond a specific range, specific gravity remains more or less constant. Growth rate shows little effect on specific gravity of juvenile wood, but with increasing age, the effect increases gradually to reach a significant level in mature wood. Growth rate does not affect specific gravity of latewood significantly, but it shows a greater effect on specific gravity of the whole ring.

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Balogh, Jeremiás Máté, and Giovanna Maria Borges Aguiar. "Determinants of Latin American and the Caribbean agricultural trade: A gravity model approach." Agricultural Economics (Zemědělská ekonomika) 68, No. 4 (April 14, 2022): 127–36. http://dx.doi.org/10.17221/405/2021-agricecon.

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Latin America and the Caribbean (LAC) region is one of the most important players in global agricultural trade. They have vast potential to strengthen their position as a result of the region's opportunities to increase agricultural production when combined with growing global demand, which could help the region's economy thrive. To discover the LAC potential agricultural trade pattern, this paper aims to analyse the determinants of LAC agricultural bilateral export for the period 1995–2019. The gravity model of trade was employed by estimating various Poisson pseudo-maximum likelihood (PPML) models including zero trade flows for panel data. The findings show that importers' GDP of LAC countries has a greater impact on agricultural trade compared to LAC exporters. Cultural similarities (common language) and countries' participation in Southern Common Market [Mercado Común del Sur (MERCOSUR)] stimulated agri-food export. Conversely, distance (transportation), past colonial links, and North American Free Trade Agreement (NAFTA) raised trade costs, having a negative impact on the export of agricultural products. The impacts of environmental regulations are ambiguous. This paper contributes to the literature by investigating the factors of agri-food export in LAC countries, which can be an important instrument for decision-makers adjusting agricultural trade policy.

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Tripathi, Buddhi Vallabh, Hemwati Nandan, and K. D. Purohit. "Global monopole in a broken-symmetric theory of gravitation." Modern Physics Letters A 32, no. 13 (April 25, 2017): 1750061. http://dx.doi.org/10.1142/s0217732317500614.

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We investigate global monopole solutions in a particular kind of scalar–tensor theory of gravity, viz. the broken-symmetric theory of gravity. Invoking the “hedgehog” ansatz for the scalar field, we derive the metric corresponding to global monopole solutions. The global monopole solutions found are independent of the scale of symmetry breaking unlike the Barriola–Vilenkin global monopoles in Einstein’s General Relativity (GR) which intrinsically depend on the symmetry breaking scale.

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Ibrahim Yahaya, Salissou, and Driss El Azzab. "ASSESSMENT OF RECENT GOCE-BASED GLOBAL GEOPOTENTIAL MODELS AND EGM2008 IN NIGER REPUBLIC." Geodesy and cartography 45, no. 3 (October 25, 2019): 116–25. http://dx.doi.org/10.3846/gac.2019.8699.

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In this study, we assessed recent GOCE-based Global Geopotential Models (GGMs) and EGM2008 in Niger. The combined GGMs EIGEN_6C4, GECO and EGM2008 were evaluated up to their maximum degree and order (d/o) 2,190 to select the one for gravity database densification. The following pure satellite GGMs were assessed for the modelling of the long and medium wavelengths in geoid computation: GGM05G, ITU_GGC16, EIGEN_6S4v2 and the fifth releases from direct (DIR5), space-wise (SPW5) and time-wise (TIM5) approaches. The GGMs are compared to terrestrial gravity data and geoid heights from GNSS/Levelling points before and after applying spectral enhancement method (SEM) by residual terrain model (RTM) for combined models and by RTM and the coefficients of selected combined GGM for pure satellite models. The agreements of combined GGMs with terrestrial gravity data and GNSS/Levelling points, in terms of root mean square (RMS) are about 4.88 to 5.02 mGal and 0.14 to 0.16 m, respectively. EIGEN_6C4 was selected as it showed the best performance in terms of geoid height differences and the probability of 3-sigma rule for gravity anomaly differences. At d/o 200, DIR5 showed a good agreement with terrestrial gravity data (5.04 mGal) and GNSS/Levelling points (0.15 m) after applying SEM, it was then retained. All GOCE-based models exhibited a good performance in long and medium wavelengths confirming the good recovery of the gravity field by the spatial gravity mission in these spectral bands.

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Apeh, O. I., E. C. Moka, and V. N. Uzodinma. "Evaluation of Gravity Data Derived from Global Gravity Field Models Using Terrestrial Gravity Data in Enugu State, Nigeria." Journal of Geodetic Science 8, no. 1 (December 1, 2018): 145–53. http://dx.doi.org/10.1515/jogs-2018-0015.

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Abstract Spherical harmonic expansion is a commonly applied mathematical representation of the earth’s gravity field. This representation is implied by the potential coeffcients determined by using elements/parameters of the field observed on the surface of the earth and/or in space outside the earth in the spherical harmonic expansion of the field. International Centre for Gravity Earth Models (ICGEM) publishes, from time to time, Global Gravity Field Models (GGMs) that have been developed. These GGMs need evaluation with terrestrial data of different locations to ascertain their accuracy for application in those locations. In this study, Bouguer gravity anomalies derived from a total of eleven (11) recent GGMs, using sixty sample points, were evaluated by means of Root-Mean-Square difference and correlation coeficient. The Root-Mean-Square differences of the computed Bouguer anomalies from ICGEMwebsite compared to their positionally corresponding terrestrial Bouguer anomalies range from 9.530mgal to 37.113mgal. Additionally, the correlation coe_cients of the structure of the signal of the terrestrial and GGM-derived Bouguer anomalies range from 0.480 to 0.879. It was observed that GECO derived Bouguer gravity anomalies have the best signal structure relationship with the terrestrial data than the other ten GGMs. We also discovered that EIGEN-6C4 and GECO derived Bouguer anomalies have enormous potential to be used as supplements to the terrestrial Bouguer anomalies for Enugu State, Nigeria.

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