Search Results (47)

This study aimed to analyze the diversification and competitiveness of corn exports from the United States, Brazil, Argentina, and Ukraine during 2020–2024 through a quantitative, descriptive design using secondary data from Trade Map. Methodologically, it applied the Herfindahl–Hirschman Index (HHI) to measure destination-market concentration and the normalized revealed comparative advantage (NRCA) to assess export specialization and relative competitiveness. The results indicated heterogeneous patterns: the United States experienced rising concentration toward Mexico—heightening vulnerability despite persistent advantages in Japan and Colombia; Brazil maintained low concentration and robust advantages across the Middle East and Asia; Argentina combined favorable diversification with stable advantages in Asia, Africa, and South America, albeit with a mild uptick in concentration by 2024; and Ukraine showed moderate diversification but volatile competitiveness, with structural disadvantages in Türkiye exacerbated by wartime logistics. This study concluded that export sustainability depended jointly on diversification and competitive specialization, with Brazil and Argentina exhibiting the strongest balance. Full article

The purpose of this article is to assess the impact of three major crises—the global economic and financial crisis of 2007–2009, the COVID-19 pandemic (2020), and the energy crisis induced by the war in Ukraine (2022)—on the condition of regional economies in Poland, both before and after their occurrence. These events, which may be regarded as black swan phenomena, were examined using several indicators of regional economic performance: the Herfindahl–Hirschman Index (HHI), the dynamics of Gross Domestic Product (GDP), industrial output sold, construction and assembly output, and retail sales. The study is based on Statistics Poland GUS data ranging from the first quarter of 2004 to the fourth quarter of 2024. The findings indicate that some Polish voivodeships (Since 1 May 2004, Poland has been divided into regions (NUTS I) and voivodeships (NUTS II). In this division, the region is statistical in nature, but in the presented research we refer exclusively to voivodeships, and therefore we also use the terms “region” and “NUTS II” interchangeably in this work. The interchangeable use of these terms also stems from the practice in Polish literature) (regions) experienced increases in industrial concentration over the study period. In 2009, during the global financial crisis, seven regions (Dolnośląskie, Lubuskie, Małopolskie, Mazowieckie, Opolskie, Podkarpackie, and Pomorskie) exhibited a relatively high degree of industrial diversification. Seven others (Kujawsko-Pomorskie, Lubelskie, Łódzkie, Śląskie, Świętokrzyskie, Wielkopolskie, and Zachodniopomorskie) showed moderate concentration. The two eastern regions—Warmińsko-Mazurskie (HHI = 194) and Podlaskie (HHI = 315)—had the highest concentration of industrial production in that year. By 2024, the overall pattern remained consistent: seven voivodeships displayed high concentration, eight moderate concentration, and one (Podlaskie) exceptionally high concentration. The degree of cyclical convergence across regions was generally high throughout the examined period. However, notable differences emerged under crisis conditions. Synchronization was strongest during the COVID-19 pandemic, when abrupt and unexpected shocks produced relatively similar regional responses. In contrast, the financial crisis of 2007–2009 and the energy crisis of 2022 generated more heterogeneous regional effects, resulting in lower and more varied levels of convergence. Full article

This study aimed to determine the degree of diversification in exports of fresh/chilled salmon and the level of international competitiveness of Norway, Sweden, Chile, and the United Kingdom over 2020–2024, using the Herfindahl–Hirschman Index (HHI) and the normalized revealed comparative advantage (NRCA). A quantitative, descriptive approach was adopted, drawing on annual Trade Map data for HS subheading 030214. HHI series were constructed by country–destination and NRCA series by country–market, and both were examined through univariate analysis. The findings showed that Norway exhibited low concentration levels and strong, stable advantages in Saudi Arabia, Türkiye, and Russia, whereas Sweden displayed moderate but rising concentration, supported by high advantages in Belgium, the United Kingdom, Germany, and Italy. In contrast, Chile and the United Kingdom recorded persistently high HHI values, with pronounced advantages concentrated in a limited number of markets (Brazil in Chile’s case; France and Chinese Taipei in the UK’s) and intra-product positions or comparative disadvantages in China, the United States, and Mexico. The study concludes that the combination of geographic diversification and positive NRCA enhances export resilience, while extreme specialization increases vulnerability to demand and regulatory shocks. It is recommended that Chile and the United Kingdom further develop diversification strategies toward markets where NRCA is neutral or negative, and that Norway and Sweden consolidate their advantages through investments in sustainability, traceability, and logistics. Further multivariate research incorporating macroeconomic and firm-level variables is also suggested. Full article

This study investigates the deep-seated impacts of the COVID-19 pandemic on Macao, a mono-economy extremely dependent on the single factor of “tourism mobility”. We investigate a counter-intuitive phenomenon observed during the 2020–2022 shock: the Herfindahl–Hirschman Index (HHI) declined significantly, suggesting “apparent diversification”. Using counterfactual simulations and a Two-Way Fixed Effects (TWFE) model, we quantitatively deconstruct this “resilience illusion”. The results confirm that the decline in the HHI was driven entirely by the “denominator effect” triggered by the collapse of the dominant industry’s (gaming) GVA; if the impact of this recession is excluded, the Counterfactual HHI was even higher than pre-pandemic levels, indicating that the structure did not undergo substantive optimization. Furthermore, inferential statistical tests confirmed the existence of significant “structural lag” in the labor market. This study further reveals a dual divergence mechanism based on “skill specificity”: in sectors with high skill universality (e.g., transport and catering), a structural shift toward “workforce casualization” occurred, manifested by a significant decline in the full-time ratio; conversely, in sectors with strong skill specificity (e.g., gaming and hospitality), firms tended toward “labor hoarding”. This study exposes the macro-indicator trap faced by tourism mono-economies under extreme shocks and provides new micro-evidence for understanding the heterogeneous scars in the service labor market. Full article

This article develops a hybrid neural network method for detecting UDP flooding in critical infrastructure microgrid protection systems. This method combines sequential statistics (CUSUM) and a multimodal convolutional 1D-CNN architecture with a composite scoring criterion. Input features are generated using packet-aggregated one-minute vectors with metrics for packet count, average size, source entropy, and HHI concentration index, as well as compact sketches of top sources. To ensure forensically relevant incident recording, a greedy artefact selection policy based on the knapsack problem with a limited forensic buffer is implemented. The developed method is theoretically justified using a likelihood ratio criterion and adaptive threshold tuning, which ensures control over the false alarm probability. Experimental validation on traffic datasets demonstrated high efficiency, with an overall accuracy of 98.7%, a sensitivity of 97.4%, an average model inference time of 5.3 ms (2.5 times faster than its LSTM counterpart), a controlled FPR of 0.96%, and a reduction in asymptotic detection latency with an increase in intensity from 35 to 12 s. Moreover, with a storage budget of 10 MB, 28 priority bins were selected (their total size was 7.39 MB), ensuring the approximate preservation of 85% of the most informative packets for subsequent examination. This research contribution involves the creation of a ready-to-deploy, resource-efficient detector with low latency, explainable statistical layers, and a built-in mechanism for generating a standardized evidence package to facilitate rapid law enforcement response. Full article

Under the dual pressures of climate change and rapid urbanization, extreme heat events pose growing risks to densely populated megaregions. The Guangdong–Hong Kong–Macao Greater Bay Area (GBA), a densely populated and economically vital region, serves as a critical hotspot for heat risk aggregation. This study develops a high-resolution multi-dimensional framework to assess the spatiotemporal evolution of its heat risk profile from 2000 to 2020. A Heat Risk Index (HRI) integrating heat hazard and vulnerability components to measure potential heat-related impacts is calculated as the product of the Heat Hazard Index (HHI) and Heat Vulnerability Index (HVI) for 1 km grids in GBA. The HHI integrates the frequency of hot days and hot nights. HVI incorporates population density, GDP, remote-sensing nighttime light data, and MODIS-based landscape indicators (e.g., NDVI, NDWI, and NDBI), with weights determined objectively using the static Entropy Weight Method to ensure spatiotemporal comparability. The findings reveal an escalation of heat risk, expanding at an average rate of 342 km² per year (p = 0.008), with the proportion of areas classified as high-risk or above increasing from 21.8% in 2000 to 33.3% in 2020. This trend was characterized by (a) a pronounced asymmetric warming pattern, with nighttime temperatures rising more rapidly than daytime temperatures; (b) high vulnerability dominated by the concentration of population and economic assets, as indicated by high EWM-based weights; and (c) isolated high-risk hotspots (Guangzhou and Hong Kong) in 2000, which have expanded into a high-risk belt across the Pearl River Delta’s industrial heartland, like Foshan seeing their high-risk area expand from 3.4% to 27.0%. By combining remote sensing and socioeconomic data, this study provides a transferable framework that moves beyond coarse-scale assessments to identify specific intra-regional risk hotspots. The resulting high-resolution risk maps offer a quantitative foundation for developing spatially explicit climate adaptation strategies in the GBA and other rapidly urbanizing megaregions. Full article

We study Portugal’s household electricity retail market after legal liberalisation, quantifying market concentration (Herfindahl–Hirschman Index (HHI) and the four-firm concentration ratio (CR4)), consumer switching, and asymmetric wholesale-to-retail price pass-through. Using monthly data for January 2014–December 2019 (primary sample) and robustness checks for 2008–2022, we compute concentration indices from ERSE supplier shares, analyse switching dynamics, and estimate nonlinear autoregressive distributed lag (NARDL) models that decompose wholesale price changes into positive and negative components. The retail market remains highly concentrated during the primary window (HHI ≈ 6300–6800 using shares expressed as percentages on a 10,000 scale); switching rose after deregulation but stabilised at moderate monthly rates; and long-run pass-through is estimated at β⁺ ≈ 0.55–0.61 for wholesale increases and β⁻ ≈ 0.49 for decreases (Wald tests reject symmetry at conventional levels). Results are robust to alternative concentration metrics, exclusion of 2022, and varied lag orders. Policy implications emphasise tariff simplification, active consumer-activation measures, and regular monitoring of concentration and pass-through metrics. Full article

Rapid advances in renewable technologies and cross-sector integration are reshaping demand for renewable hydrogen and e-fuels. This study evaluates global and European demand dynamics over 2018–2030, focusing on growth trajectories, regional convergence, and market structure. A concise empirical toolkit—including the Mann–Kendall trend test, log-linear regression, correlation analysis, and concentration metrics such as the Herfindahl–Hirschman Index (HHI)—is applied to harmonised datasets. The results indicate a robust upward trajectory of demand, strengthening co-movement across regions, and gradual deconcentration of market shares. At the same time, growth remains heterogeneous and sensitive to policy and cost shocks, implying exposure to volatility. Policy relevance includes the need for coordinated support schemes, timely infrastructure deployment, and diversified investment to capture convergence benefits while mitigating risk. The innovation resides in the demand-side, harmonised multi-region perspective and the combined utilisation of convergence- and concentration-oriented diagnostics with uncertainty bands, yielding replicable, policy-relevant indicators. Full article

This study examined the sustainability of global table grape exports from 2020 to 2024, focusing on two key dimensions: market diversification and international competitiveness. Using data from Trade Map and applying the Herfindahl–Hirschman Index (HHI) and the Revealed Comparative Advantage Normalized Index (RCAN), the research analyzed the export performance of major grape-exporting countries, including Peru, Chile, the Netherlands, Italy, the United States, South Africa, and China. The results showed significant differences in both market structure and competitive positioning. Countries like Peru and South Africa demonstrated rapid export growth and high competitiveness in certain markets, but faced elevated levels of market concentration, exposing them to external shocks. In contrast, Italy and the Netherlands maintained more diversified portfolios but showed modest competitiveness. The study concluded that no country achieved an ideal balance between diversification and competitiveness. As a result, it is recommended that governments pursue integrated trade strategies that promote geographic expansion alongside measures to enhance export competitiveness. Investments in logistics, quality certifications, and market intelligence are essential to reduce vulnerability and ensure long-term export sustainability. Full article

A greater understanding of health-promoting factors, such as hope, is crucial for preventing and enhancing the mental health of higher education students. The Herth Hope Index (HHI) is a 12-item tool that has been widely used to assess a comprehensive, non-temporal perception of hope. While this instrument has been used extensively in adult populations, most studies focus on clinical populations. Additionally, the HHI reveals inconsistencies in terms of scale dimensionality and items to be retained. Therefore, this study sought to assess the HHI’s psychometric characteristics in a sample of Portuguese Higher Education students. The person response validity, internal scale validity, unidimensionality, and uniform differential item functioning were assessed using a Rasch rating scale model. A total of 2227 higher education students participated during the e-survey activation period (spring semester of 2020). The mean age of the sample was 22.5 ± 6.2 years (range 18–59 years). Three of the twelve items (#3, #5, and #6) failed to satisfy the established criterion for goodness of fit. Following the elimination of these three items, the resultant nine-item scale exhibited satisfactory item fit to the model, appropriate unidimensionality (52.4% of the variance explained), enough person goodness of fit, sufficient separation, and the absence of differential item functioning. The 9-item version of the HHI had psychometric properties comparable to the original 12-item version. This study also underscores the importance of validated instruments for assessing hope-based interventions in academic contexts. Further research is necessary to explore the potential dimensions inherent to the hope concept and to identify variations in hope profiles among items influenced by cultural attributes. Full article

South American coffee producers face growing challenges due to external trade dependencies and climate-induced disruptions. This study investigates the role of export market diversification as a sustainability strategy for four major regional exporters of roasted non-decaffeinated coffee: Brazil, Colombia, Peru, and Ecuador. A quantitative and comparative methodology was applied over a ten-year period using the Herfindahl–Hirschman Index (HHI) to evaluate export market concentration and the Revealed Comparative Advantage (RCA) Index—including its normalized variant—to assess international competitiveness by destination. The results reveal substantial disparities: Brazil and Colombia exhibit moderate to high diversification and relative competitiveness in select markets, while Peru and Ecuador remain dependent on a few strategic buyers, with limited or declining comparative advantages. The findings emphasize that sustained export performance in the coffee sector requires not only a broader destination portfolio but also improved positioning through trade agreements, infrastructure development, and climate-resilient innovation. This study concludes with a strategic proposal based on three pillars—commercial, logistical, and technological—to support structural transformation and enhance the long-term sustainability of the coffee trade in South America. Full article

This study examines how institutional ownership concentration, quantified by the Herfindahl-Hirschman Index (HHI), influences the financial consequences of CSR initiatives within the U.S. restaurant industry. This study distinguishes between CSR activities that are integral to core operations (operation-related CSR) and those that are not (non-operation-related CSR), analyzing their impacts on both market-based (ROA) and accounting-based performance (Tobin’s q) measures. Employing panel regression analysis, findings reveal that higher institutional ownership concentration enhances the alignment of operation-related CSR with improved financial performance. Conversely, the institutional ownership concentration does not significantly moderate the impact of non-operation-related CSR on both performance measures. Given the restaurant industry’s high consumer visibility and operational reliance on social and environmental factors, this study fills gaps in CSR literature by offering insights for aligning CSR strategies with institutional owners’ expectations. The results provide actionable guidance for policymakers and industry practitioners to optimize organizational outcomes from CSR activities. Full article

Mounting evidence suggests an increasing heatwave risk in the Chinese mainland, posing notable threats to public health and the socioeconomic landscape. In a comprehensive analysis, considering both climate and socioeconomic factors, including Gross Domestic Product (GDP) and population dynamics, we systematically evaluated the spatiotemporal distribution of heatwave socioeconomic exposure in the Chinese mainland from 2000 to 2019, utilizing a more comprehensive heatwave hazard index (HHI) that synthesizes heatwave intensity, frequency, and duration as climate factor for the first time. Results show that (1) Heatwave exposure is pronounced in eastern China, particularly in Southeast (SE), North China (NC), and Southwest (SW) regions. From 2000 to 2019, heatwave exposure showed an overall upward trend, with the most rapid escalation observed in the SE, NC, and SW regions. Population exposure manifests as a clustered expansion pattern, while GDP exposure demonstrates a more centralized distribution. (2) Climatic factors exert the most notable influence on population exposure, while GDP predominantly impacts economic exposure. The combination of climate and socioeconomic factors contributes less to exposure rates, except in the Northeast (NE) and Southwest (SW) regions where it impacts GDP exposure most. (3) High-risk hotspot cities include Shanghai, Beijing, Chongqing, Guangzhou, Wuhan, Zhengzhou, Hangzhou, Xi’an, Tianjin, and Nanjing. These findings underscore the urgent need for targeted interventions and mitigation strategies in these vulnerable areas. Full article

Assessing market power in the presence of different production technologies such as renewable energies, including wind and solar power, is crucial for electric market analysis and operation. This paper investigates structural market power by incorporating wind farms and solar generation over a short-term period. The study examines the issue of market concentration boundaries to assess structural market power by calculating the minimum and maximum market concentration index values in the day-ahead market. It models the technical specifications of power plants, such as the maximum and minimum production limits, ramp-up and ramp-down rates, and minimum required up and down times. By extracting the spatiotemporal correlation of wind power generation from real data, the uncertainty of renewable power generation is represented through a set of scenarios. The analysis explores the correlation effects of wind farms, solar generation, and wind penetration levels under different ownership structures. Simulation results using a modified PJM five-bus system illustrate the effectiveness of the developed method. Our results indicate that integrating renewable energy can reduce the Herfindahl–Hirschman Index (HHI) by up to 30% as wind penetration levels rise from 0% to 40%, fostering a more competitive market structure. However, the correlation between wind farms also increases market volatility, with the standard deviation of the HHI rising by about 25% during peak load periods. These findings demonstrate the practical applicability of the developed methodology for assessing market dynamics in the presence of renewable energy sources. Full article

This research paper aims to investigate the impact of ownership concentration, insider ownership, and board size on employee productivity for 136 Jordanian public shareholding firms listed on the Amman Stock Exchange (ASE) from 2012 to 2021. Ownership concentration has been measured by Herfindahl–Hirschman Index (HHI), whereas insider ownership and board size have been represented as the proportion of shares held by insiders and by the number of board members, respectively. Lastly, employee productivity has been measured using a data envelopment analysis (DEA) tool. We employed ordinary least squares regression (OLS) including firm-year-fixed effects. Our empirical results indicate a non-linear relation between ownership concentration and employee productivity, whereby the productivity of employees increases in firms with a proportion of ownership concentration less than 60%. In addition, we found a non-linear relation between insider ownership and employee productivity, whereby the productivity of employees increases in firms with proportion of insider ownership less than 50%. Moreover, we found a non-linear relation between board size and employee productivity, whereby the productivity of employees increases in firms that have less than 11 board members. Our outcome contributed to the knowledge found in the previous literature, as it is the first to highlight the productivity of employees in emerging economies, such as the economy in Jordan. Furthermore, our findings could be useful for the Jordan Securities Commission (JSC) and the ASE on their continuous process to improve and develop corporate governance instructions. Full article