Extracting partition statistics from semistructured data

The effective grouping, or partitioning, of semistructured data is of fundamental importance when providing support for queries. Partitions allow items within the data set that share common structural properties to be identified efficiently. This allows queries that make use of these properties, such as branching path expressions, to be accelerated. Here, we evaluate the effectiveness of several partitioning techniques by establishing the number of partitions that each scheme can identify over a given data set. In particular, we explore the use of parameterised indexes, based upon the notion of forward and backward bisimilarity, as a means of partitioning semistructured data; demonstrating that even restricted instances of such indexes can be used to identify the majority of relevant partitions in the data

Exchange Rate Regimes and Economic Growth in Nigeria

In view of the fact that economic theory does not clearly identify which kind of exchange rate regime would be more likely to promote economic growth, this paper seeks to determine the differential impact of exchange rate policy on economic growth in Nigeria under a fixed and a flexible exchange rate regimes from 1973 to 2017 using the dummy variable regression model. The annual time series data of the variables that are used in the estimation of the model are obtained from The World Bank: The World Tables, 1974 and World Bank World Development Indicators. The differential intercept is positive but statistically insignificant and differential slope coefficient is positive and statistically significant, strongly suggesting that the exchange rate-economic growth regressions for the fixed and flexible exchange rate regimes are different. The slope coefficient for a flexible exchange rate regime is greater than the slope coefficient for a fixed exchange rate regime by 7.8472 units. The calculated F-statistic is greater than the tabulated F-statistic at 5 percent level of significance and at 6 and 38 degrees of freedom. This implies that there is an evidence of structural instability. The regression coefficient of exchange rate is positive and statistically significant. The result shows that the switch from a fixed exchange rate regime to a flexible exchange rate regime leads to an increase in exchange rate and the depreciation of exchange rate has significant positive impact on economic growth in Nigeria. A flexible exchange rate regime would promote economic growth more than a fixed exchange rate regime. We recommend the sustainability of a flexible exchange rate regime that has been in operation since 1986 in order to increase economic growth in Nigeria. Keywords: Exchange rate regimes, Economic growth, Dummy variable regression model, Secondary data, Nigeria DOI: 10.7176/JESD/10-18-19 Publication date:September 30th 201

Savings, Investment and Economic Growth Nexus in Nigeria

The economists disagree about the order of causality among savings, investment and economic growth. Moreover, the order of causality among savings, investment and economic growth has not been adequately or fully established in economic literature. As a result of these problems, we decided to establish the order of causality among gross domestic savings, gross domestic investment and economic growth in Nigeria from 1986 to 2017 using Vector Autoregression (VAR) model. The annual time series data of gross domestic savings, gross domestic investment and gross domestic product, a proxy of economic growth that are obtained from World Bank World Development Indicators are used in the estimation of the model. The results of the impulse response functions and variance decomposition reveal that the order of causality among gross domestic savings, gross domestic investment and gross domestic product in Nigeria, runs from gross domestic savings to gross domestic investment, gross domestic investment to gross domestic product and gross domestic product to gross domestic savings. There would be steady growth of output if adequate savings are mobilized for investment expenditures in Nigeria. Keywords: Gross domestic savings, Gross domestic investment, Economic growth, Vector autoregression model, Nigeria DOI: 10.7176/JESD/10-14-07 Publication date:July 31st 201

Disinformation Echo-Chambers on Facebook

The landscape of information has experienced significant transformations with the rapid expansion of the internet and the emergence of online social networks. Initially, there was optimism that these platforms would encourage a culture of active participation and diverse communication. However, recent events have brought to light the negative effects of social media platforms, leading to the creation of echo chambers, where users are exposed only to content that aligns with their existing beliefs. Furthermore, malicious individuals exploit these platforms to deceive people and undermine democratic processes. To gain a deeper understanding of these phenomena, this chapter introduces a computational method designed to identify coordinated inauthentic behavior within Facebook groups. The method focuses on analyzing posts, URLs, and images, revealing that certain Facebook groups engage in orchestrated campaigns. These groups simultaneously share identical content, which may expose users to repeated encounters with false or misleading narratives, effectively forming "disinformation echo chambers." This chapter concludes by discussing the theoretical and empirical implications of these findings

Application of the regression of offspring on mid-parent method to detect associations between single-nucleotide polymorphisms and the beta 2 electroencephalogram phenotype in the COGA data

The beta 2 electroencephalogram (EEG) phenotype is used as a quantitative measure related to alcoholism, and evidence of linkage and association has previously been reported in the Collaborative Study on the Genetics of Alcoholism data. In this study, associations between the beta 2 EEG phenotype and single nucleotide polymorphisms from whole-genome Illumina and Affymetrix panels were investigated with the regression of offspring on mid-parent method to identify significant genetic effects and to estimate their heritability. Separate regressions on father and mother were performed to identify parent-specific effects. Estimates of the heritability of the beta 2 EEG phenotype were 0.68 ± 0.12 and 0.52 ± 0.07 based on father-offspring and mother-offspring pairs, respectively. Significant associations at the 0.0005 level, some of which were parent-specific, were found on chromosomes 1, 2, 5, 6, 7, 8, 11, 12, 15, 16, 17, 18, and 19 with heritability attributable to each SNP ranging from 0.01 to 8%

Gas venting that bypasses the feather edge of marine hydrate, offshore Mauritania

Methane can be released from the vast marine hydrate reservoirs that surround continents into oceans and perhaps the atmosphere. But how these pathways work within the global carbon cycle now and during a warmer world is only partially understood. Here we use 3-D seismic data to identify what we interpret to be a gas venting system that bypasses the hydrate stability zone (HSZ) offshore of Mauritania. This venting is manifested by the presence of the acoustic wipe-out (AWO) across a densely faulted succession above a salt diapir and a set of morphological features including a substantial, ∼260 m wide and ∼32 m deep, pockmark at the seabed. The base of the HSZ is marked by a bottom simulating reflector (BSR) which deflects upwards above the diapir, rather than mimicking the seabed. We use a numerical modelling to show that this deflection is caused by the underlying salt diapir. It creates a trapping geometry for gas sealed by hydrate-clogged sediment. After entering the HSZ, some methane accumulated as hydrate in the levees of a buried canyon. Venting in this locality probably reduces the flux of gas to the landward limit of feather edge of hydrate, reducing the volume of gas that would be susceptible for release during a warmer world

On the importance of relative permeability data for estimating CO2 injectivity in brine aquifers

Performance assessment of possible CO2 storage schemes is often investigated through numerical simulation of the CO2 injection process. An important criterion of interest is the maximum sustainable injection rate. Relevant numerical models generally employ a multi-phase extension to Darcy's law, requiring data concerning the evolution of relative permeability for CO2 and brine mixtures with increasing CO2 saturation. Relative permeability data is acutely scarce for many geographical regions of concern and often cited as a major source of uncertainty. However, such data is expensive and time consuming to acquire. With a view to improving our understanding concerning the significance of relative permeability uncertainty on injectivity, this article presents a sensitivity analysis of sustainable CO2 injection rate with respect to permeability, porosity and relative permeability. Based on available relative permeability data obtained from 25 sandstone and carbonate cores discussed in the literature, injectivity uncertainty associated with relative permeability is found to be as high as ±57% for open aquifers and low permeability closed aquifers (100 mD), aquifer compressibility plays a more important role and the uncertainty due to relative permeability is found to reduce to ±6%