Gravity Model Research Articles

Social Attitudes Towards the Central Najdi Dialect Among Speakers of Other Najdi Dialects

This study examines the social attitudes towards the Central Najdi dialect among speakers of other Najdi dialects, i.e., Qassimi and Northern dialect. The Central dialect, spoken in the capital city of Riyadh, which has the largest population in the kingdom, is considered representative of Saudi Arabic. Based on the gravity model (Trudgill, 1974), it is hypothesized that other Najdi dialects will gravitate towards the dialect of Central Najd. The social attitudes towards the Central dialect will be assessed using the indirect method known as the verbal-guise test. The test measures individuals' implicit attitudes towards a dialect or a language. Participants listen to authentic short speech excerpts from each of the dialects understudy and rate each speaker based on selected status and solidarity traits. Findings indicate that the Central Najdi dialect is perceived more favorably in terms of status traits such as being civilized, educated, and open-minded compared to Qassimi and Northern dialect.

Integration of 2D and 3D electrical resistivity tomography and 2D gravity modeling to evaluate groundwater investigations in the Burka Uke catchment area, western Ethiopia

The increasing demand for water resources due to the expanding infrastructure and growing population of Uke town, West Ethiopia, necessitates a comprehensive understanding of groundwater potential within the Burka Uke catchment. The aims and objectives of this study are to identify a map of the aquifer by characterizing the subsurface earth, basement rock depth, resistivity and density of geological layers, their thicknesses, and structural features. The investigation integrates electrical resistivity tomography and gravity modeling to delineate potential groundwater zones and their structural controls. Electrical resistivity tomography profiles (1, 4, and 6) revealed low resistivity zones indicative of potential aquifers. The significant resistivity contrast (378 to 1412 Ω.m) suggests a high fracture density, potentially enhancing groundwater storage. The Bouguer gravity anomaly map, separated into regional and residual components, displayed values ranging from 51.79 to 41.59 mGal, highlighting density variations in the subsurface. As a result, analysis of the residual gravity anomaly map identifies north–south striking fault elements, indicating their influence on groundwater flow.The combined 2D and 3D ERT data also revealed a 2D gravity model of the aquifer from which the concentration extended throughout the study area. Data validation with previously drilled wells has confirmed the effectiveness of the geophysical methods used in identifying potential groundwater zones. This study provided critical information for the sustainable management of existing groundwater and demonstrated the effectiveness of integrating geophysical techniques to delineate and characterize aquifers in water-stressed areas.

Anisotropic Spheres with Tolman–Kuchowicz Spacetime in the Context of f(Q,T)$f(Q,T)$ Gravity

AbstractThis study primarily focuses on exploring the nature of anisotropic spheres within the framework of extended symmetric teleparallel gravity. To accomplish this, an anisotropic matter distribution for gravity model with Tolman–Kuchowicz spacetime is considered. Through this analysis, the necessary conditions for matching the interior and exterior geometries of the spheres are discussed and calculated the values of the unknown parameters involved. Furthermore, the physical properties of these spheres are analyzed using observational data from compact objects. The results demonstrate that the interior solutions obtained for anisotropic spheres fulfill all requisite physical criteria, thereby ensuring the stability of our model.

ANALYZING THE IMPACT OF FREIGHT TRANSPORT, GDP, AND PESO – BAHT EXCHANGE RATE ON PHILIPPINE TRADE IN DESICCATED COCONUT USING THE GRAVITY MODEL OF INTERNATIONAL TRADE

Objective: The objective of this study is to investigate the impact of freight transport, Gross Domestic Product (GDP), and the Peso-Baht exchange rate on the trade of desiccated coconut between the Philippines and Thailand, utilizing the Gravity Model of International Trade. The primary aim is to understand the significant factors influencing the trade flow and to identify areas for improvement in international competitiveness. Theoretical Framework: The research is grounded in international trade theories, focusing on the Gravity Model, which emphasizes the roles of economic mass and geographical distance in determining trade flows. Method: This study made use of the ADF - Unit Root Test, Durbin – Watson Test, Jarque – Bera Test, Variance Inflationary Factor (VIF), Chow Breakpoint Test, Ramsey’s RESET, and Johansen Cointegration, to test the relationship between variables. Results and Discussion: The results of this study highlights the positive, yet insignificant effect of Thailand, and Philippines’ GDP on the trade in desiccated coconut. The exchange rate, and freight transport negatively impacts the trade, however, it is notable that only freight transport having a significant effect. Research Implications: The study provides insights into the logistical and economic challenges in the desiccated coconut trade, suggesting that addressing transportation inefficiencies and stabilizing exchange rates could enhance trade performance. Originality/Value: This study contributes to the literature by applying an innovative approach to desiccated coconut, revealing how logistical inefficiencies and economic variables affect trade flows and influence policy decisions. This research aids in enhancing trade efficiency between agricultural-exporting nations like the Philippines and Thailand.

ANALYSIS OF THE GEOGRAPHICAL FACTORS INFLUENCING CHOICE OF INFORMAL FISH TRADE ROUTE AND DESTINATION BY FISH TRADERS BETWEEN MALAWI AND NEIGHBORING COUNTRIES

Choice of trade route and destination by cross border traders is an important decision in today’s increasingly cross border trade of products including fish. The current study examined the geographical factors influencing choice of informal trade route and destination by fish traders. Both qualitative and quantitative approaches were adopted for the study. These included semi-structured questionnaires through personal interviews and key informant interviews with fish border inspectors. Data was analyzed through various techniques for trader’s choice and destination. Specifically, principal component analysis and spearman correlation, and Huff’s gravity model were used to identify significant factors influencing choice of trade route and destination, and market attractiveness, respectively. Fish traders bypass official border posts using informal routes connecting the main route before and after the border post. Despite attempts and awareness about formal trade, stringent regulations forced fish traders to use informal trade routes. However, investigations into choice of trade routes and destination found that route distance, presence of alternative destination, mode of transport, demand of the fish product, and personal safety and risks were the factors influencing choice of both trade route and destination by informal fish traders. This geographic analysis provides a basis for addressing challenges in informal cross border trade in Malawi. It is recommended that strategic efforts and investments should be made in the development of transportation infrastructure, such as roads and railways to improve connectivity between secondary routes and one stop border post. The government should also intensify awareness initiatives on COMESA simplified trade regime (STR) to encourage informal traders to transition to the formal sector through use of formal routes.

Observational Test of f(Q) Gravity with Weak Gravitational Lensing

In this article we confront a class of f(Q) gravity models with observational data of galaxy–galaxy lensing. Specifically, we consider f(Q) gravity models containing a small quadratic correction when compared with general relativity (GR), and quantify this correction by a model parameter, α. To derive the observational constraints, we start by extracting spherically symmetric solutions, which correspond to deviations from the Schwarzschild solution that depends on the model parameters in a twofold way, i.e., a renormalized mass and a new term proportional to r −2. Then, we calculate the effective lensing potential, the deflection angle, the shear component, and the effective excess surface density profile. After that, we employ a group catalog and a shape catalog from the Sloan Digital Sky Survey Data Release 7 for the lens and source samples, respectively. Moreover, we handle the off-center radius as a free parameter and constrain it using a Markov Chain Monte Carlo method. Concerning the deviation parameter from GR we derive α=1.202−0.179+0.277×10−6Mpc−2 at the 1σ confidence level, and then compare the fitting efficiency with the standard Λ cold dark matter paradigm by applying the Akaike information criterion and Bayesian information criterion. Our results indicate that the f(Q) corrections alongside the off-center effect yield a scenario that is slightly favored.

Tectonic reevaluation of West Cameroon domain: Insights from high-resolution gravity models and advanced edge detection methods

The West Cameroon region, characterized by a diverse geomorphology of highlands and plains resulting from tectonic processes across different geological ages, has been extensively explored for natural resources. Recognizing the significance of its tectonic and magmatic features associated with seismic and volcanic activity, this study focuses on geodynamic investigations of the Cameroon Volcanic Line (CVL). Despite previous efforts, detailed structural geophysical studies of the West Cameroon domain have proven inconclusive, prompting a comprehensive structural reinterpretation. Utilizing the high-resolution SGG-UGM-2 satellite gravity model and innovative processing techniques, including the horizontal gradient of a modified tilt (HGSTDR), the balanced horizontal gradient (BHG), the tilt of the horizontal gradient (TAHG), the improvised horizontal gradient tilt angle (impTAHG), and the Tilt Depth method, our research aims to enhance the interpretational quality of tectonic lineaments. By separating regional and residual anomalies in the Bouguer gravity map and applying a combination of filters to delineate geological units, the BHG filter emerges as a robust tool that highlights subsurface edges without generating false features. This approach unveils previously undetected NNW-SSE-oriented lineaments, confirming the presence of deep fractures and faults in Bafoussam, Nkongsamba, and along the Benue Trough, corroborated by newly discovered NNW-SSW trending lineaments. The study suggests that the region’s topography is overcompensated by deep mountain roots and compressive tectonism. Digitizing the BHG filter produces a structural map, revealing predominant NE trends in identified geological margins, including NNE-SSW, N-S, NW-SE, E-W, and NE-SW directions. Geological contacts between granite and high-grade gneiss are indicated by NNW-SSE and NNE-SSW trending lineaments along the Benue Trough. These results contribute significantly to the understanding of the tectonic setting of the West Cameroon Domain.

Russian counter-sanctions and smuggling: Forensics with structural gravity estimation

Trade and other economic sanctions are a common foreign policy instrument, but their imposition may induce smuggling. We develop and implement procedures to study smuggling after the food embargo imposed by Russia on Western countries after the annexation of Crimea in 2014. We construct predicted trade flows for the post-sanctions period using an estimated structural general equilibrium gravity model with many industry sectors and compare those predictions with actual trade flows. We identify a substantial value of suspicious trade flows which we associate with smuggling; especially importing banned goods through third countries such as Belarus. The structural gravity model systematically under-predicts trade volumes for country-product combinations used as channels for smuggling of the banned goods. We identify a quantity of smuggling equivalent to approximately 11 to 17 percent of the pre-embargo trade flows.

Morphometry and active tectonics of the Konkan coast, western India

The Indian western coast is petroliferous drawing attention from academicians and industrial experts. In this work, geomorphic indices have been calculated to decode neotectonics of the Konkan onshore region on India’s west coast. Earthquake and Bouguer anomaly data have been used along with the present-day stress data from the World Stress Map project. Gravity modeling was performed in order to gain seismotectonic insights. The b-values were determined using Z-MAP 7.1 (2021). Morphometric analysis at both linear and spatial scales were performed using the digital elevation model from the data derived from the Shuttle Radar Topography Mission, analysed with ArcGIS 10.3 (2014) software. Maps depicting slopes, aspects, and reliefs were created. NW-SE trending lineaments in the Konkan plain guided the major stream courses. Two of the five watersheds, watersheds 4 and 5, reveal high tectonic activity, are landslide-prone and host hot springs. Interestingly, watersheds 4 and 5 show high b-values (except near the rivers’ sources), low Bouguer anomalies, and higher Hypsometric integral values (0.18523 and 0.16698) than the other watersheds. A low b-value in watershed 3 indicates stress accumulation. Over a larger area, the gravity trend varies from ∼ -80 to 30 mGal. The lineaments diagram deduced from the first vertical derivative technique shows that the structural fabrics mostly trend ∼ NW-SE at the west of the Western Ghat Escarpment (WGE) while it is NE-SW at the east. The tilt derivative ratio technique reveals a major NE-SW trend to the west of the WGE and an E-W trend to the east. Structural interpretations based on drill-cores around Koyna combined with geophysical studies for deep crust will be required are required for a better understanding of the blind (active) structures in the region.

A comprehensive analysis of observational cosmology in [formula omitted] gravity with deep learning and MCMC method

Our goal in this study is to build FRW cosmological models inside the f(Q) theory of gravity framework by using Bayesian statistics and deep learning method. We investigate the universe’s accelerating behaviour for a specific version of the f(Q) gravity model using a novel, straightforward parameterization of the Hubble parameter in the form H=H0(1+z)1+q0−q1exp(q1z). The corresponding free parameters in H(z) are limited between 1σ and 2σ confidence bounds using the χ2-minimization procedure. The results show that all the numbers we got are in the ballpark of what cosmological observations would predict. In our model, we examined the physical behaviour of the cosmos using characteristics such as energy density, pressure, and equation of state. We analysed kinematic factors including Hubble parameter, acceleration parameter, and universe age in our model. In our concept, the deceleration parameter q(z) represents the universe’s transition from deceleration to acceleration. We employ a novel approach for parameter estimation by utilizing a mixed neural network (MNN) that combines artificial neural networks (ANN) and mixture density networks (MDN). This new methodology leverages the strengths of ANN, MDN, and MNN to enhance the accuracy of parameter estimation.

Effective cooling networks: Optimizing corridors for Urban Heat Island mitigation

The detrimental impacts of the Urban Heat Island (UHI) effect are widely recognized in cities globally. Despite the natural cooling capacity of urban cold islands (UCIs), their fragmented state diminishes overall effectiveness. Previous research focused on identifying corridors to connect these isolated UCIs, aiming to enhance cooling networks. However, optimal connection strategies remained elusive. This study introduces a novel framework to address this gap. Utilizing ArcGIS Pro's optimal region connection tools alongside Morphological Spatial Pattern Analysis (MSPA) and ecological parameters, corridors in Ghaemshahr, Iran were meticulously planned and assessed. Through minimum cumulative resistance and gravity models, 63 potential corridors totaling 153 km were identified. Optimization procedures then refined this selection to 27 key corridors spanning 22 km, with 67% measuring less than 0.5 km and strategically positioned near UCIs. This prioritizes adjacency, maximizing corridor protection and construction likelihood. This cost-effective approach fosters stronger connectivity between adjacent UCIs, ultimately linking all UCIs within the region. This innovative methodology provides a holistic solution for mitigating UHI effects, promoting sustainable urban development.

On Planetary Orbits, Ungravity and Entropic Gravity

In previous works, entropic gravity and ungravity have been considered as possible solutions to the dark energy and dark matter problems. To test the viability of these models, modifications to planetary orbits are calculated for ungravity and different models of entropic gravity. Using the gravitational sector of unparticles, an equation for the contribution to the effect of orbital precession is obtained. We conclude that the estimated values for the ungravity parameters from planetary orbits are inconsistent with the values needed for the cosmological constant. The same ideas are explored for entropic gravity arising from a modified entropy–area relationship.

Expected constraints on Phobos interior from the MMX gravity and rotation observations

The origin of the Martian moons is still uncertain, and knowledge about their interior could provide support to some of its leading theories. In preparation for the JAXA Martian Moons eXploration (MMX) mission, we review our current knowledge on the interior of Phobos, and provide synthetic tests showing how the gravity and rotation determination could allow the detection of specific interior-structure properties. The inversion of the geodetic observables for the retrieval of the internal mass distribution of a set of synthetic interior models is performed via non-linear least-squares, where the interior parameterization is based on the level-set method. We additionally provide simple expressions allowing to relate some of these interior models to the geodetic observables of Phobos. The results, based on realistic measurement resolution and noise scenarios, show good retrievals for most of the models at the data resolutions expected from MMX. Specifically, we find the gravity information is realistically sufficient for the detection of mass anomalies below the Stickney crater, as well as large scale heterogeneous regions within plausible rubble-pile structures. Libration helps retrieve the more degenerate models for gravity, such as those with concentric layers or with density varying linearly with depth. The incremental improvement from further adding an hypothetical mean obliquity measurement is marginal. Finally, we apply the level-set inversion and the analytical formulas to estimate possible interior characteristics of the ‘real’ Phobos from the currently-available scarce geodetic observables. The level-set solutions for the real-data inversion generally converge to a higher mass concentration towards the surface in the equatorial region. Markov chain Monte Carlo estimations of parameters relative to a simple 2-layer model or a radial density distribution similarly hint at a lighter region inside of Phobos.

Alternative Idea About the Source of the Baryon Asymmetry of the Universe

The paper proposes an alternative scenario for the emergence of the baryon asymmetry of the Universe. This scenario is realized in the lattice gravity model associated with the Dirac field as follows. At ultrahigh temperatures of the Grand Unification order $${{T}_{c}} \sim {{10}^{{18}}}$$ GeV and higher, the system is in a PT-symmetric phase. But when the temperature decreases, a phase transition to an asymmetric phase occurs, in which a non-zero tetrad appears, that is, space-time with the Minkowski metric, and the system’s wavefunction splits into two: $$|\,\rangle = {\text{|}} + \rangle + \,{\text{|}} - \rangle $$. The fields of tetrads in states $${\text{|}} + \rangle $$ and $${\text{|}} - \rangle $$ differ in sign. At the very first moment of time with a duration of the order of the Planck time, a transition of fermions between these states is possible. These transitions in different parts of space are not correlated with each other. Therefore, the final asymmetry of the fermion charge between these states is relatively extremely small and it is preserved in time, since the interaction of the states $${\text{|}} + \rangle $$ and $${\text{|}} - \rangle $$ ceases at times greater than the Planck time.

Tectonics of Cauvery basin (India) in onshore and offshore portions

Morphometric studies coupled with geophysical investigations from petroliferous basins provide valuable information about tectonics of the regions. We deduce six morphologic parameters from the River Cauvery's designated (sub)watersheds and perform dendrogram clustering analysis. The main channels of the (sub)watersheds showcase steeper gradient and meandering nature with less concavity. On the other hand, the distributaries portray lesser gradient and straight nature with greater concavity. From the offshore region of the Cauvery basin, we perform gravity modeling. The results show variations in gravity values from low to high, -150 to 50 mGal probably because of the basement ridge-depression features. This anomaly orientation indicates the extension of the sub-basin in the region. A strong NE-SW gravity trend possibly suggests a high-density plug at mid-crust. The low gravity values near the Vedaranyam region indicate low-density rocks within the basement. Places of high gravity anomaly show a decrease in bathymetry depth and vice versa. This indicates isostatic compensation of the Moho geometry, possibly due to crustal thinning in the offshore areas. Isostatic regional gravity fields are manifested by Moho relief and can have implications on the lithospheric mechanical strengths. Bathymetric studies indicate multi-directional slopes. Relatively flat areas can indicate depocenters. E-W trending lineaments mapped on the Precambrian basement from a portion of the study area is presumably a manifestation of Cauvery Shear zone, which also persists in the offshore region.

Impact of political relationships on virtual land flow from China's food trade

The increasing backlash against globalization has shifted public opinion towards being against trade. This situation puts food trade, which is resources constrained and susceptible to political relations, into a complex dilemma. Due to the concerns on agricultural endowments, food trade needs to be considered with strategic interests because of its sensitivity and fragility. Using virtual land as a measurement to analyse the resource flows behind the food trade can provide an objective perspective on what extent a country depends on the trade. Overlaying worldwide trade disputes and political interventions, establishing solid trade relationships is increasingly becoming urgent. This study uses an extended gravity model, assesses the virtual land traded by China with 10 species over 20 years, and provides insights on establishing politics-oriented trade relationships, further testing how this political mechanism works in the food trade. The results demonstrate that memorandums of understanding are the fundamental institutional layer to guarantee trading activities and promote smooth transactions for both sides; state visits are determinable factors in establishing bilateral relationships and it significantly promote upper-middle income countries, which crucially impacts the trading system. As those endeavors undertaken by executive departments are often ignored, more attention should be paid to them during interactive stages. Political relations show differences in food trade among different countries and varieties. The promoting effect of political relations is stronger in middle and high-income countries, and the impact on Russia and Ukraine is more significant than others. Compared within varieties, foreign state visits and endeavor presents more positive on pork.

On the existence and avoidance of singularity in [formula omitted] gravity using Raychaudhuri equation

The paper deals with the modified Raychaudhuri equation in the framework of homogeneous and isotropic f(Q) gravity model subject to the parametrization f(Q)=Q+F(Q). Focusing of a congruence of time-like geodesics has been studied via the convergence condition for two choices of F(Q) namely, a polynomial in Q and an exponential form of Q. Finally, possibilities for the avoidance of initial big-bang singularity in both the models have been examined via the signature of Raychaudhuri scalar.

An Integrated Framework for Estimating Origins and Destinations of Multimodal Multi-Commodity Import and Export Flows Using Multisource Data

Estimating origin-destination (OD) demand is integral to urban, regional, and national freight transportation planning and modeling systems. However, in developing countries, existing studies reveal significant inconsistencies between OD estimates for domestic and import/export commodities derived from interregional input-output (IO) tables and those from regional IO tables. These discrepancies create a significant challenge for properly forecasting the freight demand of regional/interregional multimodal transportation networks. To this end, this study proposes a novel integrated framework for estimating regional and international (import/export) OD freight flows for a set of key commodities that dominate long-distance transportation. The framework leverages multisource data and follows a three-step process. First, a spatial economic model, PECAS activity allocation, is developed to estimate freight OD demand within a specific region. Second, the international (import and export) freight OD is estimated from different zones to foreign countries, including major import and export nodes such as international seaports, using a gravity model with the zone-pair friction obtained from a multimodal transportation model. Third, the OD matrices are converted from monetary value to tonnage and assigned to the multimodal transportation super network using the incremental freight assignment method. The model is calibrated using traffic counts of the highways, railways, and port throughput data. The proposed framework is tested through a case study of the Province of Jiangxi, which is crucial for forecasting freight demand before the planning, design, and operation of the Ganyue Canal. The predictive analytics of the proposed framework demonstrated high validity, where the goodness-of-fit (R2) between the observed and estimated freight flows on specific links for each of the three transport modes was higher than 0.9. This indirectly confirms the efficacy of the model in predicting freight OD demands. The proposed framework is adaptable to other regions and aids practitioners in providing a comprehensive tool for informed decision-making in freight demand modeling.

Impact of Economic Integration on Trade: A Case Study of Pakistan

Purpose: This paper tends to examine the impact of economic integration on trade for Pakistan. It studied all trade agreements of Pakistan with partner and non-partner nations. We test whether the trade creation (TC) and trade diversion (TD) effects on trade flows are same across for the members and non-member countries. Also, we have measured comparative advantage and comparative disadvantage. Design/Methodology/Approach: We have used correctly specified gravity model on the data of imports and exports of Pakistan starting from 1988 till 2020. We have also used Revealed Comparative Advantage (RCA) index in this research work. Findings: The results revealed from the RCA index shows that Pakistan recorded comparative advantage in most of the commodity group and less comparative disadvantage. Similarly, Pakistan is enhancing trade with partner and non-partner nations in majority of the commodity groups respectively. Implications/Originality/Value: We may conclude that Pakistan is having trade creation with its partner countries and non-partner countries in most of the agreements.

Measuring the Impact of some International Variables on Agricultural Trade (Citrus and Grapes) between Egypt and BRICS Using the Gravity Model

Measuring the Impact of some International Variables on Agricultural Trade (Citrus and Grapes) between Egypt and BRICS Using the Gravity Model