Modified gravity and cosmology
In this review we tend to gift a completely comprehensive survey of recent work on changed theories of gravity and their cosmological consequences. Amongst different things, we tend to cowl general relativity theory, scalar–tensor, Einstein–æther, and Bimetric theories, still as TeVeS, f(R), general higher-order theories, Hořava–Lifschitz gravity, Galileons, Ghost Condensates, and models of additional dimensions as well as Kaluza–Klein, Randall–Sundrum, DGP, and better co-dimension braneworlds. we tend to additionally review makes an attempt to construct a Parameterised Post-Friedmannian formalism, that may be accustomed constrain deviations from general relativity theory in cosmology, which is appropriate for comparison with information on the biggest scales. [1]
The Log of Gravity
Although economists have long been responsive to Jensen’s difference, several political economy applications have neglected a crucial implication of it: beneath heteroskedasticity, the parameters of log-linearized models calculable by OLS cause biased estimates of truth elasticities. we tend to justify why this drawback arises ANd propose an applicable calculator. Our criticism of typical practices and therefore the projected answer touch a broad vary of applications wherever log-linearized equations are calculable. we tend to develop the argument victimisation one explicit illustration, the gravity equation for trade. we discover vital variations between estimates obtained with the projected calculator and people obtained with the standard methodology. [2]
Analogue Gravity
Analogue gravity could be a analysis programme that investigates analogues of general relativistic attraction fields at intervals alternative physical systems, usually however not completely condensed matter systems, with the aim of gaining new insights into their corresponding issues. Analogue models of (and for) gravity have a protracted and distinguished history qualitative analysis back to the earliest years of general relativity theory. during this critique we’ll discuss the history, aims, results, and future prospects for the assorted analogue models. we have a tendency to begin the discussion by presenting a very easy example of associate analogue model, before exploring the wealthy history and sophisticated tapestry of models mentioned within the literature. The last decade especially has seen a noteworthy and sustained development of analogue gravity ideas, resulting in some many revealed articles, a workshop, two books, and this critique. [3]
Earth-Gravity Congruent Motion Facilitates Ocular Control for Pursuit of Parabolic Trajectories
There is proof that humans think about associate earth gravity (9.81 m/s²) previous for a series of tasks involving perception and action, the rationale being that gravity helps predict future positions of moving objects. Eye-movements successively ar partly target-hunting by predictions regarding discovered motion. Thus, the question arises whether or not information regarding gravity is additionally accustomed guide eye-movements: If humans think about a illustration of earth gravity for the management of eye movements, earth-gravity-congruent motion ought to elicit improved visual pursuit. in a very pre-registered experiment, we tend to given participants (n = 10) with parabolic motion ruled by six completely different gravities (−1/0.7/0.85/1/1.15/1.3 g), 2 initial vertical velocities and 2 initial horizontal velocities in a very 3D setting. [4]
Effect of Gravity Variation on the Growth of Wheat and Guinea Corn Seedlings
In this study, the impact of gravity on plant growths was studied to work out the orientation of the roots and shoots underneath simulated microgravity mistreatment the clinostat. The experiment was performed with 2 native seeds-wheat (Triticum aestivum) and dourah (Sorghum bicolor).
The agar answer ready was equally distributed into the petri dishes wherever 9 seeds every of wheat and dourah was planted on four petri dishes. The petri dishes containing the seeds were cultivated within the wet chamber for concerning 20-30 hours. 3 petri dishes were selected within the following order, 1g, 90o turned and clinorotated samples severally. 5 readings were taking at thirty minutes interval. [5]
Reference
[1] Clifton, T., Ferreira, P.G., Padilla, A. and Skordis, C., 2012. Modified gravity and cosmology. Physics reports, 513(1-3), (Web Link)
[2] Silva, J.S. and Tenreyro, S., 2006. The log of gravity. The Review of Economics and statistics, 88(4), (Web Link)
[3] Barcelo, C., Liberati, S. and Visser, M., 2011. Analogue gravity. Living reviews in relativity, 14(1), (Web Link)
[4] Earth-Gravity Congruent Motion Facilitates Ocular Control for Pursuit of Parabolic Trajectories
Björn Jörges & Joan López-Moliner
Scientific Reports volume 9, Article number: 14094 (2019) (Web Link)
[5] Aluko, O. E. and Onabowale, M. K. (2019) “Effect of Gravity Variation on the Growth of Wheat and Guinea Corn Seedlings”, Journal of Experimental Agriculture International, 29(3), (Web Link)
