Determining the acceleration of a free-falling object due to gravity is a standard experiment in physics. Different methods to do this have been developed over the years. The development of video-analysis tools have provided yet another method. The use of videos opens up the possibility of studying more complex and exotic situations. If there is a video available and a known scale it is possible to analyse the motion. One of the most spectacular demonstrations of free fall was performed by Commander David Scott during the Apollo 15 mission to the Moon. He held out a hammer and a feather, dropped them at the same time, and being in vacuum they fell at essentially the same rate, as concluded by Galileo Galilei 400 years ago. This video, available on NASA's website , makes it possible to deter mine the acceleration due to gravity on the Moon using video analysis.
In this paper, we introduce the notion of g-variance and study some properties of this operator. We find the nonlinear variance operator, g-variance, does not preserve some basic properties of traditional mathematic variance. We also consider the relationship
We prove that the theories of fields with Hasse-Schmidt derivations corresponding to actions of formal groups admit model companions. We also give geometric axiomatizations of these model companions.
Navaneethakrishnanan, M.
Joseph, J. Paulraj
Sivaraj, D.
I(g)-normal and I(g)-regular spaces are introduced and various characterizations and properties are given. Characterizations of normal, mildly normal, g-normal, regular and almost regular spaces are also given.
Parameters and abundances for 1133 stars of spectral types F, G, and K of luminosity class III have been derived. In terms of stellar parameters, the primary point of interest is the disagreement between gravities derived with masses determined from isochrones, and gravities determined from an ionization balance. This is not a new result per se, but the size of this sample emphasizes the severity of the problem. A variety of arguments led to the selection of the ionization-balance gravity as the working value. The derived abundances indicate that the giants in the solar region have Sun-like total abundances and abundance ratios. Stellar evolution indicators have also been investigated with the Li abundances and the [C/Fe] and C/O ratios, indicating that standard processing has been operating in these stars. The more salient result for stellar evolution is that the [C/Fe] data across the red-giant clump indicates the presence of mass-dependent mixing in accord with standard stellar evolution predictions.
In this chapter we investigate (g, f)-factors and [a, b]-factors, which are natural generalizations of f-factors and regular factors, respectively. We first give a criterion for a graph to have a (g, f)-factor, which is called the (g, f)-factor theorem. Then we obtain some sufficient conditions for graphs to have (g, f)- factors and [a, b]-factors.
Wiege, K.
Ali, S. R.
Gewecke, B.
Novakovic, A.
Konrad, F. M.
Pexa, K.
Beer-Hammer, S.
Reutershan, J.
Piekorz, R. P.
Schmidt, R. E.
Nurnberg, B.
Gessner, J. E.
Zhu, Yongping
Zhang, Lei
Zhang, Xuejun C.
Zhao, Yongfang
The heterotrimeric G proteins (G alpha beta gamma) act as molecular switches to mediate signal transduction from G protein-coupled receptors to downstream effectors. Upon interaction with an activated receptor, G protein exchanges its bound GDP with GTP, stimulating downstream signal transmission. Release of GDP requires a structural rearrangement between the GTPase domain and helical domain of the G alpha subunit. Here, we used single molecule fluorescence resonance energy transfer (smFRET) technique to study the conformational dynamics of these two domains in the apo state and in the binding of different ligands. Direct imaging of individual molecules showed that the G(i)alpha subunit is highly dynamic, and at least three major conformations of G(i)alpha could be observed in the apo state. Upon binding of GDP, G(i)alpha becomes dramatically less dynamic, resulting in a closed conformation between the two domains. We postulate that changes between the three conformations are sequential, and the three conformations appear to have distinct affinities toward GDP. (C) 2017 Elsevier Inc. All rights reserved.