Statistical Tools Research Articles

Machine learning-based approach KEVOLVE efficiently identifies SARS-CoV-2 variant-specific genomic signatures.

Machine learning was shown to be effective at identifying distinctive genomic signatures among viral sequences. These signatures are defined as pervasive motifs in the viral genome that allow discrimination between species or variants. In the context of SARS-CoV-2, the identification of these signatures can assist in taxonomic and phylogenetic studies, improve in the recognition and definition of emerging variants, and aid in the characterization of functional properties of polymorphic gene products. In this paper, we assess KEVOLVE, an approach based on a genetic algorithm with a machine-learning kernel, to identify multiple genomic signatures based on minimal sets of k-mers. In a comparative study, in which we analyzed large SARS-CoV-2 genome dataset, KEVOLVE was more effective at identifying variant-discriminative signatures than several gold-standard statistical tools. Subsequently, these signatures were characterized using a new extension of KEVOLVE (KANALYZER) to highlight variations of the discriminative signatures among different classes of variants, their genomic location, and the mutations involved. The majority of identified signatures were associated with known mutations among the different variants, in terms of functional and pathological impact based on available literature. Here we showed that KEVOLVE is a robust machine learning approach to identify discriminative signatures among SARS-CoV-2 variants, which are frequently also biologically relevant, while bypassing multiple sequence alignments. The source code of the method and additional resources are available at: https://github.com/bioinfoUQAM/KEVOLVE.

Socio-Economic Factors Affecting Children Hawkers in Moba Local Government of Ekiti State

The study investigated socio-economic factors affecting children hawkers in Moba local government area of Ekiti State. The study adopted the descriptive design of the survey type. The sample size in this study was 50 teachers. Three research questions were raised and answered in the study. The instrument used for data collection was a researcher-designed questionnaire titled “Socio-economic factors affecting hawkers in Moba LGA of Ekiti State.” Data collected were analysed using statistical tools that were employed to answer the research questions such as mean and standard deviation. The findings revealed that high cost of living is associated with street hawking among children. It was also showed that large family size is associated with street hawking among children in Moba Local Government of Ekiti State. The result revealed that poverty is associated with street hawking among children.Based on the results of this study, it was recommended that there is need for government continuous enlightenment of parents on the effect involving their children in street hawking and the importance of education. Government to create more job opportunities so that citizens would be employed to enable then cater for family needs. Government should make education free at all levels so that the less privileged children would have the opportunity to be educated. Government should legislate against involving children of school age in hawking and punish parent, guardian and caregiver who go against it. There is a need to protect the child, advocate reduction in family size, poverty and promote parental education/economic empowerment in order to reduce the urge on children to perform economic roles. They should also improve the standard of living of the citizens through provision of bursary allowance to the indigent citizens.

DNA methylation profiling of labial salivary gland tissues revealed hypomethylation of B-cell-related genes in primary Sjögren's syndrome.

The objective of this epigenetic study was to investigate the cellular proportions based on DNA methylation signatures and pathways of differentially methylated genes in labial salivary gland (LSG) tissues of individuals with Sjögren's syndrome (SS). Two methylation array datasets from the Gene Expression Omnibus repository (GSE166373 and GSE110007) were utilized, consisting of 159 LSG tissues from 77 SS cases and 82 non-SS controls. The raw data underwent analysis using the Chip Analysis Methylation Pipeline (ChAMP) in R statistical tool, which identified differential methylation probes and regions. The EpiDISH and minfi packages in R were employed to identify proportions of epithelial cells, fibroblasts, and immune cells, as well as immune cell subsets. The results showed that proportions of immune cells were increased, while proportions of epithelial cells and fibroblasts were significantly decreased in the LSG of individuals with SS compared to non-SS controls. Specifically, proportions of B-cells and CD8 T-cells were increased, while CD4 T-cells, Treg, monocytes, and neutrophils were decreased in the LSG of individuals with SS. Pathway analysis indicated that genes involved in immune responses to Epstein-Barr virus infection were significantly hypomethylated in SS, and gene set enrichment analysis highlighted the hypomethylation of genes involved in the somatic recombination of immune receptors in SS. Additionally, Disease Ontology analysis showed enriched pathways related to multiple myeloma, arthritis, and the human immunodeficiency virus. The study also revealed significant hypomethylation of the WAS gene on chromosome X in LSG tissues of individuals with SS. Overall, the findings suggest an increased proportion of B-cells and genes related to B-cell function, as well as hypomethylation of genes involved in immune responses and immune receptor recombination, in LSG tissues of individuals with SS compared to non-SS controls.

An Individual Rehabilitation and/or Habilitation Program for Children with Disabilities (IPRH)

Introduction: The individual program of rehabilitation and (or) habilitation of children with disabilities (IPRH) is mandatory for execution by the relevant state authorities, local self-government bodies, as well as organizations regardless of organizational-legal forms and forms of ownership. Objective: To conduct a pilot analysis of the implementation of the IPRH contingent of patients of children with disabilities in an urban children’s clinic. Patients and methods: There were 366 reports on the implementation of measures provided for by an IPRH for a disabled person (disabled child) of 222 disabled. The organization of the study was in the nature of a continuous sample. The criterion for the inclusion of patients in it was the passage of an IPRH in a disabled child within a specified time frame. The following techniques were used: grouping, absolute and relative values, average values, detailing, and generalization. The threshold error probability for statistically significant differences was set at a level of 0.05. Results: The structure of the results of the control of the performance of IPRH in 222 disabled children according to the classes of diseases that caused the onset of disability (ICD) was as follows 1) G00-G99 - 35.47 ± 3.13%; 2) Q00-Q99 - 23.50 ± 2.77%; 3) 11.11 ± 2.05%; 4) C00-D48 - 10.25 ± 1.98%; 5) H60-H95 - 7.26 ± 1.67%; 6) M00-M99 - 2.99 ± 1.11%; 7-8) H00-H59 and P00-P96 - 2.14 ± 0.95%; 9-10) K00-K93 and S00-T98 - 1.29 ± 0.74% each; 11-12) I00-I99 and N00-N99 - 0.85 ± 0.60% each; 13-14) J00-J99 and L00-L99 - 0.43 ± 0.42% each. Conclusion: 1. In the structure of IPRH in 222 disabled children, according to the classes of diseases that caused disability (ICD), the following prevailed: 1) VI Diseases of the nervous system G00-G99 – 35.47%; 2) XVII Congenital anomalies, chromosomal disorders Q00-Q99 - 23.50%; 3) IV Diseases of the endocrine system, nutritional disorders, and metabolic disorders E00-E90 – 11.11%; 4) II Neoplasms C00-D48 - 10.25%; 5) VIII Diseases of the ear and mastoid process H60-H95 - 7.26%; 6) XIII Diseases of the musculoskeletal system and connective tissue M00-M99 - 2.99%; 7-8) VIII Diseases of the ear and mastoid process H60-H95 and VII Diseases of the eye and its adnexa H00-H59 - 2.14% each. 2. The effectiveness of medical rehabilitation of disabled children was as follows: 1) Improvement - 23.26%; 2) Stabilization - 74.88%; 3) Deterioration - 1.86%. Dynamic observation was carried out on 94.26% of disabled children, drug therapy - 77.32%, non-drug therapy - 66.93%, and other types of medical rehabilitation were received by 14.48% of patients. Reconstructive operations were performed on 11.26% of disabled children. 3. Prosthetics and orthotics were performed on 38.74% of disabled children. 32.43% of disabled children in need received sanatorium treatment, and 30.18% are currently in line to receive a voucher. For various reasons, 24.32% refused this type of rehabilitation; 3.60% of patients had contraindications at the time the voucher was provided. 4. The obtained research results become the initial everyday statistical tool for objectifying the process of rehabilitation of patients and determining the strength and means of a medical institution to monitor and successfully implement an individual rehabilitation/habilitation program for a disabled person

KNOWLEDGE, ATTITUDE, AND BEHAVIOR OF THE ELDERLY TOWARDS THE IMPLEMENTATION OF COVID-19 VACCINATION IN SOUTH NIAS, INDONESIA: A CROSS SECTIONAL STUDY

Despite the susceptibility of the elderly to COVID-19, vaccination coverage in this age group is still far from Indonesia's national target. This research studied the implementation of the COVID-19 vaccine in Teluk Dalam, South Nias District, in 2021 and analyzed the relationship between knowledge, attitudes, and behaviour of the elderly towards implementing vaccination. It was a mixed-method study with an explanatory design. The population of this study included the elderly in Teluk Dalam, with a total of 33 people serving as research samples and three informants for qualitative data. Data were obtained by administering questionnaires and interviews, analyzed by the SPSS statistical tool with chi-square test at α = 5%, and compared with the collected qualitative data. The results showed that the elderly in Teluk Dalam's knowledge of implementing the COVID- 19 vaccine was still low, with negative attitudes and behaviour. There was a significant relationship between knowledge, attitudes and behaviour of the elderly towards implementing COVID-19 vaccination in Teluk Dalam, South Nias District (p <0.05). It is recommended that the elderly attend counselling given by health workers so that they can increase their knowledge about the implementation of the COVID-19 vaccination and change their attitude and behaviour and want to take part in the COVID-19 vaccination and health workers to provide information about the implementation of the COVID-19 vaccine to the public, especially the elderly more specific.

Alternate pathway for regional flood frequency analysis in data-sparse region

Accurately analyzing flood frequency is crucial for developing effective flood management strategies and designing flood protection infrastructure, but the complex and nonlinear nature of the hydrological system poses significant challenges. The use of advanced statistical techniques, hydrological modeling, and computational tools has facilitated the implementation of several regional flood frequency analysis (RFFA) methods, including machine learning (ML) approaches. However, such regional methods, being statistical and data-intensive with limited hydrologic inferences, can be challenging for regions with limited data. In this study, we evaluated an alternate approach or path for RFFA in two contrasting regions: a data-sparse region in India and a data-dense region in the USA. The alternate approach involves using deep learning (DL)-based model for streamflow prediction, followed by at-site flood frequency analysis to estimate flood quantiles. The proposed alternate approach was compared with the classical RFFA method, which utilized the Random Forest (RF) and eXtreme Gradient Boosting (XGBoost) algorithms to establish the intricate relationship between different flood quantiles and predictor variables related to physio-meteorological conditions. The findings showed that the alternate approach outperformed the classical RFFA method in the data-sparse region of India, reducing the mean absolute error (MAE) and root mean squared error (RMSE) by approximately 50 %, and achieving a higher coefficient of determination (R2 = 0.85 to 0.96). In the data-dense region, the classical and alternate approaches produced comparable results. However, the alternate approach has the benefit of flexibility and offers a complete time series of daily flow at the ungauged watersheds, enabling the estimation of other flow attributes or magnitudes for any return period without needing a separate classical RFFA model. The study demonstrates that the alternate approach can produce reliable flood quantile estimates in regions with limited data, offering a promising solution for managing floods in these areas.

THE INFLUENCE OF THE AUDITOR'S INDEPENDENCE, COMPETENCE, INTEGRITY, ETHICS ON THE QUALITY OF THE AUDIT IN THE GENERAL INSPECTION OFFICE OF THE TIMOR-LESTE STATE

The aim of this research is to provide empirical evidence regarding the influence of Auditor Independence, Auditor Competence, Auditor Integrity and Auditor Ethics on Audit Quality at the Timor Leste Inspecsaun Geral do Estado (IGE). The populution in this research is all employees who carry out functions as auditors, totaling 32 staff auditors. However, the sample used in this research and also in the data processing process was 30 respondents, where the sampling technique was using the census method, data collection was using questionnaires and statistical analysis tools were using Multiple Linear Regression analysis.

Happiness at work: a systematic literature review

Purpose This study aims to systematically review the literature on happiness at work (HAW) by analysing existing studies, identifying relevant themes in HAW research and evaluating the methodologies used in the literature. Design/methodology/approach The study used a systematic review process, following the guidelines and principles outlined in the updated Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement 2020 and checklist. Articles were collected from six databases: Emerald insight, Taylor & Francis Online, Science Direct, Wiley Online Library, Springer and MDPI. Subsequently, systematic review was performed on 41 HAW articles published in 29 different journals between 2010 and 2022. The authors only considered articles that were either indexed by Scopus or in the Academic Journal Guide (AJG) list. Findings The study identified six major themes, assessed the operationalisation of HAW and analysed the research methodologies and statistical tools used in the sample studies. Majority of the articles discussed the antecedents of HAW followed by the HAW as a mediator. There is a high heterogeneity in the operationalisation of HAW in the reviewed articles. Moreover, majority of the studies have prioritised service sectors over the industrial sectors. Originality/value This study represents the first comprehensive review of the existing literature on HAW by using a systematic review methodology.

Household electricity consumption determinants in major Nigeria cities

The increasing epileptic electricity supply, mainly in the residential areas of Nigerian cities, has been linked to the incorrect knowledge of the numerous socio-economic and physical indices that influence household electricity usage. Most of the seemingly identified explanatory factors were done at macro level which does not give a clear estimate of this electricity demand. The thrust of the study is to analyse empirically the household electricity determinants in Nigerian cities with a view to evolving a more informed and sustainable energy policy decision. Multistage area cluster sampling method was adopted in the study where 769 copies of structured questionnaire were distributed to electricity users of prepaid meters in five major Nigerian cities. The research hypothesis was tested using the multiple linear regression statistical tool. The result revealed that nine variables which include age (r = 0.05, p-value: 0.05), household income (r = 0.00, p-value: 0.05), number of hours that people stay outside the house (r = 0.043, p-value: 0.05), number of teenagers at home, (r = 0.006, p-value: 0.01) number of electrical appliances (r = 0.016, p-value: 0.01), type of house (r = 0.012, p-value: 0.01), hours that the electrical appliances are used (r = 0.043, p-value: 0.05), weather condition, (r = 0.011, p-value: 0.05) and the location of the building (r = 0.045, p-value: 0.05) were significant in determining the household electricity consumption. Policies based on the findings will give energy and urban planners an empirical basis for accurate and robust forecasting of the determinants that influence household electricity consumption in Nigeria that is devoid of any speculation or unfounded predictions.

Discrete modelling of continuous dynamic recrystallisation by modified Metropolis algorithm

Continuous dynamic recrystallisation (CDRX) is often the primary mechanism for microstructure evolution during severe plastic deformation (SPD) of polycrystalline metals. Its physically realistic simulation remains challenging for the existing modelling approaches based on continuum mathematics because they do not capture important local interactions between microstructure elements and spatial inhomogeneities in plastic strain. An effective discrete method for simulating CDRX is developed in this work. It employs algebraic topology, graph theory and statistical physics tools to represent an evolution of grain boundary networks as a sequence of conversions between low-angle grain boundaries (LAGBs) and high-angle grain boundaries (HAGBs) governed by the principle of minimal energy increase, similar to the well-known Ising model. The energy is minimised by a modified Metropolis algorithm. The model is used to predict the equilibrium fractions of HAGBs in several SPD-processed copper alloys. The analysis captures non-equilibrium features of the transitions from sub-grain structures to new HAGB-dominated grain structures and provides estimations of critical values for HAGB fractions and accumulated strain at these transitions.

Incidence of Energy Consumption, Mining Sector and Economic Growth on CO2 Emission Levels: Evidence from Peru

Environmental pollution and its harmful effects have become a growing topic of study in recent years because the exploitation of resources, rationalized by the prevailing desire for economic growth, is going to directly affect the sustainability of our existing ecosystem in the coming decades. This is considering that there are productive sectors that have a larger environmental footprint, such as the mining industry. This study focuses on establishing the relationship between the variables of energy consumption, GDP per capita, and mineral rents and their impact on the level of pollution by CO2 emissions in the period 1971–2019, using the Environmental Kuznets Curve (EKC) theory. To this end, we used statistical and econometric tools based on the ARDL dynamic model through a time series analysis starting from historical data. We concluded that the variables CEpc, PBIpc, and RM have deleterious effects as a 1% increase in these variables increases the level of environmental pollution by CO2 emissions by 0.724%, 0.136%, and 0.061%, respectively.

Assessing the Impact of Phosphorus 30C and 200C Potencies on the Growth and Yield of Pisum Sativum (Green Pea)

Pisum Sativum is one of the commonest crops grown in India. Therefore, increasing the yield of green pea plants without harming the soil with chemicals are important. In places wherever there is deficiency of phosphorus in soil resulted in decreased production of green pea plants. The parameters were analysed by using statistical tool ANOVA test. The Conclusion derived from the study was Phosphorus 200C has significantly influenced in the growth and yield of Pisum Sativum plant in regards to Height of the plant, Number of Pods per Plant, Length of the Pod, and Number of Seeds per Pod.

A Study of the Use of Computer –Mediated Language Learning on Oral English Pedagogy in Oyo State, Nigeria

This paper examines the use of Use of Computer –Mediated Language Learning in Oral English Pedagogy in Oyo State, Nigeria through the theoretical foci of Herring’s (2011) Computer- mediated Language Teaching and Nelson’s (2011) Intelligibility in ESL in World Englishes. Questionnaires were administered among 300 students and 30 teachers from 15 purposively sampled secondary schools from 5 geo-political zones of Oyo State. Respondents were gathered through stratified-random sampling technique. Method of data analysis was through simple percentage statistical tool. The findings revealed that there was scarcity of digital gadgets to teach Oral English in Oyo State secondary schools, pedagogy of Oral English is done through improvisation in Oyo State, the pedagogy of the English language in Oyo State schools occurs in an unconducive environment, and the use of digital tools in teaching oral and other aspects of English is bedeviled by epileptic power supply. It was recommended that government, philanthropist and non-governmental organizations should team up to equip Oyo State secondary schools with automated gadgets to teach Oral English in Oyo State secondary schools so as not only to make learners speak English that is mutually acceptable among Nigerians and internationally intelligible, but also to develop learners’ performance in English in external examinations.

A Study of the Use of Computer –Mediated Language Learning on Oral English Pedagogy in Oyo State, Nigeria

This paper examines the use of Use of Computer –Mediated Language Learning In Oral English Pedagogy in Oyo State, Nigeria through the theoretical foci of Herring’s(2011) Computer- mediated Language Teaching and Nelson’s (2011) Intelligibility in ESL in World Englishes. Questionnaires were administered among 300 students and 30 teachers from 15 purposively sampled secondary schools from 5 geo-political zones of Oyo State. Respondents were gathered through stratified-random sampling technique. Method of data analysis was through simple percentage statistical tool. The findings revealed that there was scarcity of digital gadgets to teach Oral English in Oyo State secondary schools, pedagogy of Oral English is done through improvisation in Oyo State, the pedagogy of the English language in Oyo State schools occurs in an unconducive environment, and the use of digital tools in teaching oral and other aspects of English is bedeviled by epileptic power supply. It was recommended that government, philanthropist and non-governmental organizations should team up to equip Oyo State secondary schools with automated gadgets to teach Oral English in Oyo State secondary schools so as not only to make learners speak English that is mutually acceptable among Nigerians and internationally intelligible, but also to develop learners’ performance in English in external examinations.

Profitability and Determinants of Output of Rice Production in Anambra State, Nigeria

The study examined the profitability and determinants of output of rice production in Anambra State, Nigeria. The specific objectives were to: estimate the profitability of rice production; establish the determinants of production output; and identify constraints to rice production in the area.Multistage, purposive and random sampling methods were used to select respondents. Though 378 copies of the questionnaire were administered to the farmers by personal interview, 315 adequately filled copies were sorted and used in data collation. Primary data used for the study were collated and analyzed by means of descriptive and inferential statistical tools such as the enterprise budgeting technique (gross margin, net farm income, mean net farm income and net return on income) Ordinary Least Squares (OLS) regression, One- way ANOVA and Scheffe’s Multiple Comparison test. Findings on the profitability of rice production in the area showed that per hectare gross margin figures were N315,300, N285,600, N302,800 and N301,233 for Anambra, Aguata and Awka Agricultural zones, and the State (study area) respectively. Net return on investment figures were 1.49, 1.23, 1.30 and 1.35 respectively. The NROI values indicate that for every N1.00 investments in rice productions in the three zones and the State the farmers are likely to realize on one hectare N1.49 in Anambra Agricultural zone, N1.23 in Aguata zone, N1.30 in Awka zone and on the average N1.35 in the State, hence rice production is a profitable enterprise in the area. Meanwhile, Schefee’s Multiple Comparison test indicated no significant difference between per hectare mean net farm incomes realized by farmers from paired agricultural zones. Findings on the influence of socio-economic characteristics of the farmers on production output indicated that five regressors (educational level, farming experience, farm size, amount of credit obtained and cost of inputs) exerted independent and statistically significant influences on output while the rest six did not have significant influence on output. Constraints to rice production posited insufficient fund as the most serious problem of rice production in the area, followed by scarcity and high cost of labour, scarcity and high cost of quality seeds, among others. Government should encourage financial institutions to make loans available to farmers and form cooperative societies to obtain bulk purchase of high quality seeds and other input resources.

Prediction Penalized Analysis of Stroke Based on New Bayesian Hierarchical Priors Model

The penalized or the regularization methods nowadays are the most statistical popular tools used for model selection and variable selection procedure. The quality of the regression parameter estimates depends on the prediction accuracy of the estimated model and the model interpretability. Penalized operator methods usually produced the most parsimonious model (less number of predictor and more explanation). This paper utilized new scale mixture of Rayleigh mixing with normal density to study the relationship between the stroke size and some predictors. New hierarchical priors model has developed as well new Gibbs sampling algorithm. The results demonstrated that the proposed model is comparable to some exists regularization models.

Predictive Value of Blocks of Time, Open Door Policy, Closed-door Policy and Time-management Practices: Lessons for Leaders

The study examined the predictive value of blocks of time, open-door policy and closed-door policy on senior-member administrators time-management practices in the Technical Universities in Ghana. The main objective was to assess whether open-door policy, closed-door policy and blocks of time have impact on time-management practices of senior-member administrators. Two hypotheses were generated based on the objectives to guide the study. Predictive design was used for the study. Four hundred and forty-five senior-member administrators were selected through purposive sampling. Questionnaire was used to elicit responses from participants. The overall alpha coefficient of the items measured (α =.91) was obtained. Pearson correlation and hierarchical regression were the statistical tools used to analyse the data gathered. The findings indicated among others that there existed statistically significant and relationship between open-door policy, close-door policy, blocks of time and time-management practices. Findings equally showed that open-door policy made the strongest unique contribution to the prediction of time-management practices. The findings were discussed in relation to the literature. It was recommended among others that senior member administrators should be conscious of reinforcing the use of open-door policy, closed-door and blocks of time at the detriment of other variables. Specific time that can most conveniently help senior-member administrators to receive visitors and operate successfully should be pasted in front of the office door to control influx of visitors and avoid missing deadlines.

Enhancing pharmaceutical wastewater treatment: Ozone-assisted electrooxidation and precision optimization via response surface methodology

Amid the critical global demand for effective wastewater treatment, our study presents a pioneering approach to address pharmaceutical wastewater treatment. We exploited the potential of electrooxidation (EO) and introduced an innovative process with ozone-assisted electrooxidation (EO/O3), using Pt-coated Ti electrodes (Pt/Ti). The core aim is to tackle the removal of organic pollutants in terms of chemical oxygen demand (COD), color, and the UV absorption peak at 300 nm (UV300). This endeavor took place in a carefully controlled batch-mode reactor. Rigorous experimental design and optimization methodology was conducted using the cutting-edge statistical tool known as the Box-Behnken Design (BBD). Using current density, initial pH, and electrolysis time as independent variables in our statistical models resulted in remarkable outcomes. Under optimized conditions (110.63 A m−2 current density and pH 4.5 in 477 min), our stand-alone electrooxidation effectively reduced COD by 70.5 %, color by 81.25 %, and decreased UV300 by 40.01 %. However, when ozone joined the stage to assist the electrooxidation, the performance raised to new heights. It achieved an impressive 84 % reduction in COD, a remarkable 99.43 % color decrease, and a significant 49.63 % drop in UV300 under optimized conditions (150 A m−2 current density and pH 8.79 in 480 min). In addition, this study was further distinguished by the positive results obtained in the kinetic analysis. The findings showcase ozone-assisted electrooxidation as a highly effective approach for pharmaceutical wastewater treatment, emphasizing the novelty and significance of this study.

Visualizing Convergence Dynamics across Regions and States: h-Convergence

Researchers interested in studying whether convergence dynamics are in place among regions within the same country have adopted both statistical tools and empirical frameworks developed when studying convergence across different economies. We show that this approach is risky, because when an analysis is conducted at the regional level, the absolute and club convergence processes are more likely to co-exist than in the case of world economies. We propose an empirical approach where the two hypotheses are not taken as competing. Our procedure uncovers periods of convergence and periods of divergence for the three samples we studied: Italy observed at both the regional and provincial levels; EU regions; and world economies. We find a process of absolute convergence for Italian regions from 1951 to 1999, and that their convergence process ends in 1971 after a period which we define as clustering convergence. We also find a process of convergence across European regions from 1977 to 1993; that ends in 1985 in favor of a process of clustering and divergence. Finally, our procedure uncovers a process of absolute convergence from 1964 to 1975 and divergence from 1975 to 1999 in the case of world economies.

Recreational Fishing and Biodiversity in Mostaganem: Species Richness, Trophic Level, and Ecological Status of the Population Caught

The objective of this study is to evaluate the impact of recreational fishing on the marine ecosystem in the Mostaganem region, through the assessment of targeted and captured biodiversity, based on annual monitoring, using different statistical tools. The results show a wide range of species caught by boaters, with a total of 79 species belonging to 38 families and 24 orders, dominated by bony fish (86%). Biodiversity varies seasonally, due to the opportunistic behavior of boaters in targeting species according to their availability in the fishing grounds by using different gears and techniques at different seasons of the year. These boaters mainly target predators at high trophic level and high economic value, in order to maximize their income, which has negative effects on the top of the food chain, thereby creating a cascading effect on species at a lower trophic level. Thus, 12% of these species are classified as endangered or vulnerable, indicating considerable risks to fisheries resources and the marine ecosystem and its sustainability, suggesting effective management measures to ensure the sustainability of this recreational activity by minimizing environmental impacts.