scholarly journals A study on causality in f(R,ϕ,X) theory

2021 ◽  
Vol 36 (02) ◽  
pp. 2150009
Author(s):  
J. S. Gonçalves ◽  
A. F. Santos
Keyword(s):  
Gravity Model ◽  
Critical Radius ◽  
Gravitational Model ◽  
Modified Formula

The [Formula: see text]-essence modified [Formula: see text] gravity model, i.e. [Formula: see text] theory is studied. The question of violation of causality, in the framework of Gödel-type universes, is investigated in this gravitational model. Causal and noncausal solutions are allowed. A critical radius for noncausal solution is calculated. It is shown that the violation of causality depends on the content of matter.

ANALYSIS OF POLISH INTERNATIONAL TRADE WITH NEIGHBORING COUNTRIES, USING GRAVITY MODEL

2018 ◽  
Vol XX (5) ◽  
pp. 173-178 ◽  
Author(s):  
Piotr Pomichowski ◽  
Maria Parlińska
Keyword(s):  
International Trade ◽  
Gravity Model ◽  
Dairy Products ◽  
Raw Materials ◽  
Meat Products ◽  
Fruit And Vegetables ◽  
Gravitational Model ◽  
Linder Hypothesis

The aim of the study was to examine whether there are non-tariff barriers (NTB s) in Poland’s trade with neighboring countries and in what amounts. For this purpose, a gravitational model of international trade was used, in which the parameters of selected variables were estimated in 4 agri-food sectors: agricultural raw materials, dairy products, food, fruit and vegetables, and meat products. The estimation of NTB s was the smallest in all sectors mentioned in Poland’s exports to Slovakia. The largest restrictions except for the dairy sector occur in Poland’s trade with Ukraine. The largest non-tariff barriers in Poland’s trade with neighbors occur in the agricultural raw materials sector, and the smallest in meat products. In addition, the model confirmed the veracity of the Linder hypothesis.

Internal migration in Italy. Long-run analysis of push and pull factors across regions and macro-areas of the country.

2016 ◽  
Vol 13 (3) ◽  
pp. 443-454
Author(s):  
Piras Romano
Keyword(s):  
Gravity Model ◽  
Internal Migration ◽  
Empirical Studies ◽  
Great Majority ◽  
Pull Factors ◽  
Push And Pull Factors ◽  
Long Run ◽  
Italian Regions ◽  
Migration Flows ◽  
Push And Pull

The great majority of empirical studies on internal migration across Italian regions either ignores the long-run perspective of the phenomenon or do not consider push and pull factors separately. In addition, Centre-North to South flows, intra-South and intra-Centre-North migration have not been studied. We aim to fill this gap and tackle interregional migration flows from different geographical perspectives. We apply four panel data estimators with different statistical assumptions and show that long-run migration flows from the Mezzogiorno towards Centre-Northern regions are well explained by a gravity model in which per capita GDP, unemployment and population play a major role. On the contrary, migration flows from Centre-North to South has probably much to do with other social and demographic factors. Finally, intra Centre-North and intra South migration flows roughly obey to the gravity model, though not all explicative variables are relevant.

An Advanced Guide to Trade Policy Analysis​: The Structural Gravity Model

2016 ◽  
Author(s):  
Yoto V. Yotov ◽  
Roberta Piermartini ◽  
José-Antonio Monteiro ◽  
Mario Larch
Keyword(s):  
Policy Analysis ◽  
Trade Policy ◽  
Gravity Model

Improving Demand Forecasting Accuracy for Cultural Facilities Using Gravity Model

2020 ◽  
Vol 24 (2) ◽  
pp. 121-163
Author(s):  
Yun Ju Ham ◽  
Yun Jun Kim ◽  
Geun Seok Hong
Keyword(s):  
Gravity Model ◽  
Demand Forecasting ◽  
Forecasting Accuracy

TRADE FLOWS BETWEEN CIS COUNTRIES: DOES THE GRAVITY MODEL WORK NOW?

2020 ◽  
Author(s):  
Ольга Сергеевна Чудинова ◽  
Екатерина Николаевна Корнейченко ◽  
Ольга Борисовна Чаганова ◽  
Анастасия Михайловна Ротова
Keyword(s):  
Gravity Model ◽  
World Trade ◽  
Trade Flows ◽  
Cis Countries

В статье представлены результаты проверки адекватности гравита-ционной модели в условиях глобализации мировой торговли. По статистическим данным для стран СНГ за 2011-2018 годы на основе гравитационной модели исследовано влияние масштаба экономики торговых партнеров и расстояния между странами на объем импорта. The article presents the results of assessing the adequacy of the gravity model in the context of world trade globalization. According to statistics for the CIS countries for 2011-2018 the effect of size of economies and distance between the countries on import volumes is studied on the basis of gravity model.

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