Search Results (29,572)

The large-scale integration of renewable energy has significantly improved the low-carbon performance of power systems, but has also increased operational uncertainty. Under extreme weather conditions, wind and solar power may experience consecutive days of simultaneous output shortfalls—referred to as “renewable energy drought”—leading to persistently high net load and severe challenges to supply guarantee. To address this issue, this paper proposes a multi-source coordinated supply-guarantee dispatch strategy for consecutive-day renewable energy drought scenarios. First, net load is defined as the total system load minus the available wind and solar output. Based on magnitude and duration thresholds, renewable energy drought events are extracted from historical data to generate representative scarcity scenarios. Second, a multi-source coordinated optimization dispatch model is constructed, incorporating wind power, solar power, thermal units, battery energy storage, and pumped-storage hydro. The objective is to minimize the total system operating cost, which includes thermal fuel cost, start-up/shut-down costs, storage cycling cost, wind/solar curtailment penalty cost, and load shedding penalty cost. The load shedding penalty coefficient is set to a magnitude much higher than conventional costs to highlight the priority of supply guarantee. The model accounts for operational constraints such as minimum up/down times, deep regulation capability, ramping limits of thermal units, and charge/discharge power limits of storage. Taking a provincial power system in China for the year 2030 as a case study, a dispatch case covering four consecutive days (96 time periods) is designed. Based on a baseline scenario, eight groups of sensitivity analyses are conducted to comprehensively investigate the impacts of key factors on the supply-guarantee strategy, including: the minimum up/down time of thermal units, deep regulation capability, load shedding penalty cost, load level, rated energy capacity and charge/discharge efficiency of battery energy storage, rated energy capacity and pumping/generating efficiency of pumped-storage hydro, thermal fuel cost coefficient, and renewable energy capacity. Simulation results show that the proposed strategy can effectively coordinate multiple resources under consecutive-day drought conditions; reducing the minimum up/down time of thermal units improves supply flexibility but increases start-up/shut-down costs; enhancing deep regulation capability optimizes storage utilization and reduces total system cost; the load shedding penalty cost directly determines the trade-off between supply guarantee and economic efficiency; and as load level decreases by 5%, 10%, and 15%, the total system operating cost reduces by approximately 6.3%, 12.5%, and 18.8%, respectively. This study provides a quantitative method and technical support for supply-guarantee dispatch decisions and resource allocation in high-renewable power systems under persistent drought conditions. Full article

Growing up without parental care may negatively affect adolescents’ behavioral and emotional development, particularly among adolescents in conflict with the law. In a selected secure care center in the Vhembe District, limited research has explored the lived experiences and behavioral impact of growing up without parents. This study aimed to explore and describe the behavioral and emotional impact of growing up without parents among adolescents in conflict with the law in a child and adolescent secure care center in Limpopo Province. A qualitative, explorative, descriptive, and contextual research design was employed. Purposive sampling was used to recruit twelve (12) adolescents aged 15–17 years admitted to a secure care center in the Vhembe District. Data was collected through individual semi-structured interviews conducted in Xitsonga or Tshivenda, depending on participants’ preferred language. Interviews were audio-recorded, transcribed, translated into English, and analyzed using Tesch’s eight steps of data analysis. Ethical considerations and measures to ensure trustworthiness were observed throughout the study. The findings revealed that adolescents experienced low self-esteem, diminished self-confidence, early initiation of substance use, poor educational engagement, survival-oriented delinquent behavior, and feelings of neglect. These findings highlight the need for an integrated intervention approach to ensure coordinated psychosocial, educational, behavioral, and socio-economic support for this population. Full article

Megaprojects’ global expansion yields profound socio-economic and environmental effects, highlighting the significance of megaproject social responsibility (MSR). Stakeholders of megaprojects must possess a thorough understanding of what drives MSR behavior to formulate impactful governance strategies. Despite research advances in understanding MSR behavior triggers, the field lacks a holistic and systematic perspective, failing to adequately explain the driving mechanism behind behavior. This study conducted a qualitative analysis based on the motivation–opportunity–ability (MOA) framework to explore current practices and identify the drivers of MSR behavior. By gathering interview data from 10 megaproject experts and textual materials of three prominent megaprojects, we identified fifteen first-order concepts within seven second-order themes under the MOA framework and provided a more comprehensive and nuanced view of the drivers of MSR behavior. This study introduces a novel theoretical perspective and analytical framework, enhancing comprehension and interpretation of MSR behavior and enriching the theoretical underpinning of social responsibility management in megaprojects. Full article

The diffusion and application of advanced and applicable agricultural technologies serve as critical support for realizing the green transition and promoting high-quality agricultural development. This study constructs a two-dimensional analytical framework encompassing external intervention, internal motivation, and behavioral response. Based on micro survey data collected from 675 rice-growing households across Jiangsu Province, China, this study empirically examines the impact of agricultural technology extension services, a representative form of external intervention, on farmers’ adoption of the One-time Fertilization Technology for Mechanized Transplanting Rice (OFT), and its underlying mechanisms. The results demonstrate that external intervention acts as the core exogenous driver of farmers’ adoption of advanced agricultural technologies, with its transmission effect dependent on the mediating and moderating functions of farmers’ internal perceptions. Agricultural technology extension services facilitate technology adoption primarily by improving farmers’ technical cognition and enhancing their value perception. Notably, the effectiveness of extension services is more pronounced among farmers with higher levels of risk perception. The effect of external intervention is jointly shaped by the endowment of regional extension resources and the inherent demand of farmers, with significantly stronger extension effects observed in less developed major agricultural production areas compared to economically developed regions. This study concludes that promoting the adoption of advanced agricultural technologies requires sustained efforts to strengthen the supply of extension services, optimize the design of extension service content, implement differentiated extension strategies, and fully align with the characteristics of farmers’ risk preferences and regional heterogeneity. Full article

Assessing the sustainability of urban development, including road changes, is increasing from year to year and requires clear indicators for robust decision-making tools to gain knowledge across regions. This study conducts the selection of transportation routes over a longer period as an example to evaluate the sustainability of historical official routes in achieving economically cost-efficient operation and maintenance. Official ways in the Qiantang River Basin connected the Jiangnan region, the economic center of China, with surrounding provinces were assessed. During the past six hundred years, the official road network in this area gradually simplified, evolving from valley roads to river banks, which covered longer distances. However, this transformation lacks a systematic explanation. By applying the analytic hierarchy process (AHP) with geographic information system (GIS), quantitative analysis was gained and the results are as follows: (1) Among the influencing factors, the weights of transportation cost and population related to economic needs are 39.54% and 29.52% respectively, with a combined total of 69.06%. (2) The official road network is often designed for governing the people, but in places such as the Qiantang River Basin, economic logic superseded political imperatives, becoming the dominant factor in reshaping the official ways. (3) In the pre-industrial era characterized by limited technological capacity, the physical environment had a greater impact on economic costs, ultimately reshaping the spatial configuration of official route networks. Overall, the evolution of official routes reflects the decline in their military-political function, driven by sustained peace and long-term decline in strategic position. The evolution of the official ways in the Qiantang River Basin reveals the importance of economic benefits in road selection. Full article

Using panel data from 282 prefecture-level and above cities in China, this study employs a difference-in-differences (DID) model to examine the impact of the National Sustainable Development Plan for Resource-Based Cities on carbon emission efficiency, as well as its underlying mechanisms and heterogeneous effects. The results indicate that the implementation of the Plan significantly improves carbon emission efficiency. This conclusion remains robust after a series of robustness tests, including the propensity score matching difference-in-differences (PSM-DID) approach. Mechanism analysis further reveals that technological innovation, industrial upgrading, and reductions in energy consumption constitute the primary channels through which the Plan enhances carbon emission efficiency. In addition, economic growth pressure and the degree of marketization exert negative and positive moderating effects, respectively, on the relationship between the Plan and carbon emission efficiency. Heterogeneity analysis shows that the positive effect of the Plan is significant only in resource-based cities located in eastern China, southern China, or southeast of the Hu Huanyong Line. In terms of city size, the positive effect is observed only in medium-sized cities and Type II large cities. Full article

Background: The financial burden of diagnostic testing for obstructive sleep apnea (OSA) represents a substantial barrier to treatment initiation, with cost-related access disparities disproportionately affecting the low-income and underinsured population. Home sleep testing (HST) offers a cost-effective diagnostic alternative, yet economic patterns across provider types remain unclear. This study assessed whether board-certified sleep medicine provider (BCSMP) status is associated with differences in provider-billed HST charges and evaluated how organizational and payment contexts influence these charges. Methods: A retrospective cross-sectional analysis was conducted using 2019 data from Optum’s de-identified Clinformatics^® Data Mart Database (N = 61,531 adult HST claims). The main exposure was provider status (BCSMP vs. non-BCSMP). The outcome was total provider-requested charge per HST procedure. Generalized Linear Models with a gamma distribution estimated adjusted charge differences, controlling for organizational context, place of service, and payer type. Results: BCSMP encounters had significantly lower adjusted mean HST charges than non-BCSMPs (mean difference: −$78.04; 95% CI: −$89.06 to −$67.02; p < 0.001). Individual practitioners charged $168.48 less than hospital-affiliated providers, while group practices and other facilities charged more (all p < 0.001). Fee-for-service arrangements were associated with lower charges than commercial and Medicare Advantage plans (p < 0.001). Conclusions: Board-certified sleep medicine providers and individual practice settings were associated with lower billed charges for home sleep testing; however, these findings do not necessarily reflect actual cost reduction. To translate these baseline charge differences into equitable clinical protocols and healthcare policies, future research must analyze negotiated reimbursement rates, billing structures, and practice environments to determine how these cost parameters impact the overall cost of an OSA diagnosis. Full article

Improving regional economic resilience is a point addressed in the sustainable development goals (SDGs; i.e., SDG 8 and SDG 11). The Yangtze River Delta (YRD) has demonstrated excellent economic resilience during the COVID-19 pandemic, largely due to the persistent green transition of the YRD in the past two decades. This paper uses a single-case method combined with the perspective of evolutionary economic geography to systematically investigate the process of green transition in the YRD (2000–2023) at both vertical and horizontal levels and proposes an integrated multi-dimensional system framework to reveal the collaborative logic of the overall green transition action and the internal mechanism of enhancing economic resilience in the YRD. The findings indicate that the combination of external factors such as contradiction change, magnifying crises, economic stabilization, and policy steering has driven the historical inevitability of green transition in China. Under such conditions, the YRD not only completed development in terms of primitive accumulation of space (coordinated development, i.e., chassis), industry (orderly upgrade, i.e., engine), and governance (equal supply, i.e., lubricant) earlier but also ensured the stability of this triangle, injecting sustained strong momentum into the rapid recovery of the economy under the impact. The solidification of green concepts further enhances the sustainability and strength of the YRD’s economic resilience. These findings provide beneficial experience on how to resume production after the pandemic or lay out cities in developing countries that are still in rapid urbanization in advance. Full article

Against the backdrop of a new wave of scientific and technological revolution and industrial transformation, artificial intelligence has emerged as a pivotal technology for fostering new quality productive forces and advancing high-quality development, and is profoundly reshaping firms’ production organization and governance structures. Using data on Chinese A-share listed companies from 2016 to 2024, this study empirically examines the impact of AI on corporate internal control quality and its underlying mechanisms. The results indicate that AI significantly improves corporate internal control quality, mainly by enhancing firms’ human capital and reducing agency costs. Further heterogeneity analysis shows that the positive effect of AI on internal control quality is more pronounced among manufacturing firms, firms with higher levels of digital infrastructure, and firms with greater information transparency. From the perspective of internal corporate governance, this study extends the literature on the economic consequences of AI and provides empirical evidence on how AI, as embedded in a complex socio-technical system, empowers high-quality corporate development through institutional governance mechanisms. The findings also offer useful implications for governments seeking to refine AI-related policies and for firms aiming to promote the coordinated upgrading of intelligent transformation and internal control systems. Full article

This paper investigates a stochastic differential portfolio game between two competing investors with relative wealth preferences. The financial market consists of one risk-free asset and one risky asset, whose price dynamics follow the CEV model. We formulate this game as two utility maximization problems, where each investor aims to maximize their relative utility defined as the weighted average of the ratio between their terminal wealth and the competitor’s terminal wealth. Firstly, we derive the Hamilton–Jacobi–Bellman (HJB) equations and corresponding value functions through the dynamic programming principle. Next, we obtain the explicit solutions to equilibrium investment strategies and value functions for the non-zero-sum game under the CRRA utility framework. Finally, we conducted numerical simulations to analyze the impacts of model parameters on equilibrium strategies and provide relevant economic explanations. Full article

Background/Objectives: Chronic heart failure (CHF) is a leading cause of global morbidity and mortality, particularly among older adults, significantly impacting their quality of life and imposing a substantial economic burden. While pharmacological and surgical treatments remain essential, non-pharmacological interventions led by nurses are gaining prominence due to their comprehensive approach and biopsychosocial impact. The objective of this study was to synthesise and integrate such interventions for community-dwelling older adults with CHF. Methods: An integrative review was conducted in accordance with the Joanna Briggs Institute protocols and the PRISMA statement, utilising a systematic search across databases including PubMed and Cochrane. Qualitative, quantitative, and mixed-methods studies evaluating non-pharmacological interventions in the home setting were included, whilst those targeting non-specific populations were excluded. Following a rigorous screening process, 12 studies were selected, and their methodological quality was appraised based on study design. Results: The 12 included studies involved a total of 2466 participants and addressed interventions across the domains of education, physical activity, telehealth, and nutrition, with programme durations ranging from 4 weeks to 16 months. Notable improvements were observed in physical capacity, cognitive function, quality of life, and self-care capabilities, alongside potential reductions in hospitalisations reported in some studies. However, considerable methodological variability was identified across the literature. Conclusions: This review synthesises non-pharmacological nursing interventions for older adults with CHF, demonstrating varied benefits across multiple biopsychosocial domains. The findings emphasise the critical need for further research to evaluate the economic viability of these programmes and to adapt interventions to enhance the delivery of community-based care. Full article

In the context of the global energy transition and China’s “double carbon” strategy, power demand continues to grow, leading to expanded power plant construction that faces challenges such as spatial resource conflicts and multi-objective trade-offs. Multi-objective optimization methods are widely used for coordinating economic, environmental, and social objectives in power plant site selection. This paper systematically reviews the application of multi-objective optimization in power plant site selection using bibliometric and classification methods. The review covers four dimensions, namely, research trends, objective functions, constraints, and optimization algorithms, thereby constructing a reference framework. The study revealed that research began in 2008, with wind farm site selection now accounting for the greatest proportion. Objective functions can be summarized into four dimensions: energy and utilization, costs or benefits, engineering feasibility, and environmental and social impacts. There are six types of constraints for optimization: economic, technical, environmental, social, resource, and spatial. Genetic algorithms and their variants are the most widely used. This framework enhances the scientific rigor of power plant site selection and supports feasibility assessment, providing methodological references for site selection for power plants. Full article

Demographic disparities in mathematics proficiency have been a persistent issue in the United States public schools for the entire history of the public school system. Previous research suggests that schools serving predominantly minority students often face challenges related to fewer certified teachers and lower mathematical achievement levels. This paper investigates how school demographic composition and socioeconomic conditions are associated with differences in mathematics achievement across Alabama public schools. Focusing on the relationship between school demographics and teacher qualifications, it examines how racial composition and economic disadvantage impact student outcomes. Data on mathematics proficiency, teacher certification, experience, and school demographics were analyzed. T-test results revealed significant differences in mathematics achievement between students attending predominantly white schools and those attending predominantly schools serving historically marginalized populations, including schools serving large proportions of economically disadvantaged students. Although linear regression showed a weak overall correlation between teacher experience and proficiency, the relationship between teacher certification and student performance was significantly different from zero, suggesting a meaningful connection. Full article

The paper examines the macroeconomic and environmental outcomes associated with green financing across 22 emerging markets and developing economies from 2002 to 2024. Driven by the increased policy focus on climate finance as a two-fold tool of sustainability and development, the analysis assesses whether green financing is an economic growth driver. A multi-model structure is used (fixed effects, non-linear (quadratic), threshold, dynamic (lagged), and first-difference specifications) to achieve strength and eliminate model-specific bias. The findings show that green financing exhibits a weak positive association with economic growth in baseline and regime specifications. Still, this relationship is not robust across dynamic and first-difference models. Moreover, there is no indication of non-linearity or a threshold effect (a Green Laffer Curve). Patterns that indicate a weak positive relationship are cross-sectional and not robust to panel estimation; they are therefore aggregation-biased. Conversely, green financing has a low negative correlation with CO₂ emissions, indicating partial environmental efficiency. The results show that climate finance is limited in scale and inefficiently structured, which limits its macroeconomic impact. In general, the paper concludes that green finance, although environmentally applicable, is not sufficient as it currently stands to spur economic growth in emerging economies. Full article

Fire ants are known for their aggressive behavior, omnivorous diet, and construction of mounds on the soil surface. Their dispersal is facilitated by trade and habitat fragmentation, which have led to negative impacts on biodiversity, public health, and agriculture in many countries. In Brazil, information about their impacts is scarce and mostly limited to reports from the North Region. In the Atlantic Forest, a biome where most of Brazil’s population resides, there are no records of impacts associated with fire ants. This study examined farmers’ perceptions of the impacts of fire ants in the Atlantic Forest. A questionnaire was administered to collect information on respondents’ profiles, property characteristics, perceived impacts of fire ants, management practices, and health-related issues. Most respondents reported the regular presence of fire ants on their properties, although the perceived impacts on agricultural productivity were generally low to moderate, and control costs were typically less than $17. Widespread use of pesticides for fire ant control is reported by most farmers. Regarding stings, 85.1% of farmers reported having been stung, but only 0.6% required hospitalization. The most common reaction was itching. This pioneering study revealed that, although fire ants are present on many properties within the Atlantic Forest, the reported economic and health impacts are lower than expected, with most farmers experiencing minimal losses. Overall, the results for our sample suggest that the presence of fire ants does not result in significant economic losses for farmers. Nevertheless, fire ants are not overlooked, as non-conservationist control methods are employed. Such practices may lead to colony fragmentation, increasing their abundance and potentially negatively affecting local biodiversity. Full article