Results 81 to 90 of about 69,393 (296)
Space WeatherAtmospheric neutral density is a crucial component to accurately predict and track the motion of satellites. During periods of elevated solar and geomagnetic activity atmospheric neutral density becomes highly variable and dynamic.
K. Murphy +7 more
doaj +1 more source
Simulation of the Gravsat/Geopause mission [PDF]
A simulation of the proposed low Gravsat and high Geopause satellite mission is presented. This mission promises fundamental improvements in the accuracy of low order geopotential coefficients by using satellite-to-satellite tracking technology coupled ...
Argentiero, P. D., Koch, D. W.
core +1 more source
The Anatomical Record, EarlyView.A new musculoskeletal reconstruction and revision of the cranio‐mandibular anatomy of the Devonian arthrodire placoderm Dunkleosteus terrelli from a comparative and functional anatomical perspective. Dunkleosteus is a specialized arthrodire with many specializations for feeding on large vertebrates, and many of its features are part of broader ...
Russell K. Engelman +4 more
wiley +1 more source
Benchmarking Forecasting Models for Space Weather Drivers
Space Weather, 2020 Space weather indices are commonly used to drive operational forecasts of various geospace systems, including the thermosphere for mass density and satellite drag.
Richard J. Licata +2 more
doaj +1 more source
The Anatomical Record, EarlyView.Abstract Tyrannosaurus is viewed as a model organism in vertebrate paleontology, with numerous studies analyzing its feeding biomechanics. Nonetheless, the evolution of this feeding performance has been under‐addressed in Tyrannosauroidea, especially in basal tyrannosauroids. Here we used muscle‐force reconstruction and finite element analysis (FEA) to
Evan Johnson‐Ransom +4 more
wiley +1 more source
Influences of Space Weather Forecasting Uncertainty on Satellite Conjunction Assessment
Space WeatherA significant increase in the number of anthropogenic objects in Earth orbit has necessitated the development of satellite conjunction assessment and collision avoidance capabilities for new spacecraft.
William E. Parker +6 more
doaj +1 more source
Evaluation of the DTM-2009 thermosphere model for benchmarking purposes
Journal of Space Weather and Space Climate, 2012 Aims: The Drag Temperature Model (DTM) is a semi-empirical model describing the temperature, density, and composition of the Earth’s thermosphere. DTM2009 and DTM2000, and the COSPAR reference models NRLMSISE-00 and JB2008, are evaluated in order to ...
Guijarro Nuria +3 more
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The Anatomical Record, EarlyView.Abstract Differences in skull and tooth morphology, stomach contents, and estimated bite force between medium‐to‐large sized (≥100 kg) predatory theropod dinosaurs have long been suspected to correlate with differences in their diets and dietary guilds (e.g., hypercarnivory, piscivory).
Cassius Morrison +9 more
wiley +1 more source
National Geodetic Satellite Program, Part II: University of California, Los Angeles [PDF]
Satellite orbit analyses are presented which were undertaken for: (1) reasons of insight and economy; (2) obtaining geophysically interesting tesseral harmonics; (3) comparing effects of tracking station location error drag, radiation pressure, and luni ...
Kaula, W. M.
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Archaeological Prospection, EarlyView.ABSTRACT In Upper Mesopotamia, the transition from the Pre‐Pottery Neolithic A (PPNA) to Pre‐Pottery Neolithic B (PPNB) period, ca. 10 800–10 600 cal. BP, is marked by a series of changes in chipped stone industries, architectural forms, symbolic objects, regional distribution of settlements and long‐distance exchange networks among others.
Toshihiro Tada +7 more
wiley +1 more source