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Journal of Environmental Sciences 2024年第5期139卷 114-122页

作者： Paula Fernández González María José Presno Manuel Landajo department of Applied economics University of OviedoAuda del Cristos/n 33011 OviedoSpain

The reduction of GHG emissions to reverse the greenhouse effect is one of the main challenges in this century.In this paper we pursue two objectives.First,we analyze the evolution of GHG emissions in Spain in 2008–2018,at both the global and sectoral levels,with the variation in emissions decomposed into a set of determining factors.Second,we propose several actions specifically oriented to more tightly controlling the level of emissions.Our results showed a remarkable reduction(18.44%)in GHG emissions,mainly due to the intensity effect,but also to the production-per-capita effect.We detected somewhat different patterns among the various sectors analyzed.While the intensity effect was the most influential one in the agricultural,transport,and others sectors,the production-per-capita effect was predominant in the case of industry.The carbonization effect was revealed as crucial in the commerce sector.The above findings highlight the importance of the energy efficiency measures taken in recent years in the Spanish economy,also pointing to the need to deepen those strategies and to propose new measures that entail greater efficiency in emissions.Additional efforts in areas like innovation,R&D,diffusion of more eco-friendly technologies,and a greater use of greener energies all prove to be essential reduction actions to fight the greenhouse effect.

关键词： LMDI Decomposition Spain GHG emissions

Financial and non-financial determinants of the indebtedness of hospitals:the case of Poland

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Journal of Management Analytics 2024年第1期11卷 26-44页

作者： Katarzyna Miszczyńska Elżbieta Antczak department of Banking Faculty of Economics and SociologyUniversity of LodzLodzPoland department of Spatial Econometrics Faculty of Economics and SociologyUniversity of LodzLodzPoland

The performance of Polish healthcare is still far from satisfactory,which is connected with growing indebtedness that adversely affects not only the development of healthcare but also the quality of medical services provided.In turn,the financial situation of hospitals depends on various indicators and the relationship between them.This paper investigates the determinants of healthcare sector functioning in the context of hospitals’financial situation(dependent variable measured by total debt ratio).321 individual public units were examined between years 2007–2017.More specifically,the fixed effects panel data model in question measures and evaluates the impact of economic,regional,institutional,and social factors in determining the dependent variable.This study confirmed dependencies between financial and non-financial ratios along with their impact on the financial condition of studied entities.The management implications of our study lay the groundwork for the improvement of efficient resource management for public hospitals.

关键词： polish healthcare system hospitals’financial situation debt ratio panel data analysis

Brent vs.West Texas Intermediate in the US petro derivatives price formation

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Petroleum Science 2024年第1期21卷 729-739页

作者： Alejandro Almeida Antonio A.Golpe Juan Manuel Martín-Alvarez Jose Carlos Vides Universidad Internacional de La Rioja Department of Quantitative Methods for Economics and BusinessLa RiojaSpain University of Huelva Department of Economics and Centro de Estudios Avanzados en FisicaMatematicas y Computacion and ICEIHuelvaSpain Complutense University of Madrid Department of Applied and Structural Economics and History and ICEIMadridSpain

In this paper,we apply the spatial panel model to explore the relationship between the dynamic of two types of crude oil prices(WTI and Brent crude oil)and their refined products over time.Considering the turbulent months of 2011,when Cushing Oklahoma had reached capacity and the crude oil export ban removal in 2015 as breakpoints,we apply this method both in the full sample and the three resultant regimes.First,results suggest our results show that both WTI and Brent display very similar behaviour with the refined products.Second,when attending to each regime,results derived from the first and third regimes are quite similar to the full sample results.Therefore,during the second regime,Brent crude oil became the benchmark in the petrol market,and it influenced the distillate products.Furthermore,our model can let us determine the price-setters and price-followers in the price formation mechanism through refined products.These results possess important considerations to policymakers and the market participants and the price formation.

关键词： Crude oil prices Spatial panel model Refined products Price formation

Grouping tree species to estimate basal area increment in temperate multispecies forests in Durango,Mexico

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forest Ecosystems 2024年第1期11卷 1-13页

作者： Jaime Roberto Padilla-Martínez Carola Paul Kai Husmann Jose Javier Corral-Rivas Klaus von Gadow department of forest economics and Sustainable Land-use Planning Faculty of Forest Sciences and Forest EcologyUniversity of GottingenBüsgenweg 137077GottingenGermany Facultad de Ciencias forestales Universidad Juarez del Estado de DurangoRío Papaloapan y Boulevard Durango S/N34120DurangoMexico Faculty of forestry and forest Ecology Georg-August-UniversitatBüsgenweg 537077GottingenGermany department of forestry and Wood Science Faculty of AgriSciencesStellenbosch UniversityStellenbosch Private Bag X1Stellenbosch7602South Africa

Multispecies forests have received increased scientific attention,driven by the hypothesis that biodiversity improves ecological resilience.However,a greater species diversity presents challenges for forest management and research.Our study aims to develop basal area growth models for tree species cohorts.The analysis is based on a dataset of 423 permanent plots(2,500 m^(2))located in temperate forests in Durango,Mexico.First,we define tree species cohorts based on individual and neighborhood-based variables using a combination of principal component and cluster analyses.Then,we estimate the basal area increment of each cohort through the generalized additive model to describe the effect of tree size,competition,stand density and site quality.The principal component and cluster analyses assign a total of 37 tree species to eight cohorts that differed primarily with regard to the distribution of tree size and vertical position within the community.The generalized additive models provide satisfactory estimates of tree growth for the species cohorts,explaining between 19 and 53 percent of the total variation of basal area increment,and highlight the following results:i)most cohorts show a"rise-and-fall"effect of tree size on tree growth;ii)surprisingly,the competition index"basal area of larger trees"had showed a positive effect in four of the eight cohorts;iii)stand density had a negative effect on basal area increment,though the effect was minor in medium-and high-density stands,and iv)basal area growth was positively correlated with site quality except for an oak cohort.The developed species cohorts and growth models provide insight into their particular ecological features and growth patterns that may support the development of sustainable management strategies for temperate multispecies forests.

关键词： Temperate multispecies forests Cluster analysis Basal area increment Generalized additive models

Invasive ant learning is not affected by seven potential neuroactive chemicals

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Current Zoology 2024年第1期70卷 87-97页

作者： Henrique Galante Tomer J.Czaczkes department of Zoology and Evolutionary Biology Animal Comparative Economics LaboratoryUniversity of Regensburg93053 Regensburg Germany

Argentine ants Linepithema humile are one of the most damaging invasive alien species worldwide.Enhancing or disrupting cognitive abilities,such as learning,has the potential to improve management efforts,for example by increasing preference for a bait,or improving ants'ability to learn its characteristics or location.Nectar-feeding insects are often the victims of psychoactive manipulation,with plants lacing their nectar with secondary metabolites such as alkaloids and non-protein amino acids which often alter learning,foraging,or recruitment.However,the effect of neuroactive chemicals has seldomly been explored in ants.Here,we test the effects of seven potential neuroactive chemicals-two alkaloids:caffeine and nicotine;two biogenic amines:dopamine and octopamine,and three nonprotein amino acids:β-alanine,GABA and taurineon the cognitive abilities of invasive L.humile using bifurcation mazes.Our results confirm that these ants are strong associative learners,requiring as little as one experience to develop an association.However,we show no short-term effect of any of the chemicals tested on spatial learning,and in addition no effect of caffeine on short-term olfactory learning.This lack of effect is surprising,given the extensive reports of the tested chemicals affecting learning and foraging in bees.This mismatch could be due to the heavy bias towards bees in the literature,a positive result publicationbias,ordifferences inmethodology.

关键词： associativelearning caffeine memory neuroactivechemicals

Whether to Abolish or Introduce Dual Regulation as Trade and Environmental Policy?

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China & World Economy 2024年第1期32卷 57-95页

作者： Yoshihiro Hamaguchi department of economics Faculty of Economics and Business AdministrationKyoto University of Advanced ScienceJapan

China,which has already introduced an environmental tax in an effort to decarbonize,has recently begun emissions trading and is using two environmental policies in tandem,but there are concerns about the impact on growth and trade.Trade and environmental policies affect firms'entry and exit,resulting in changes in aggregate productivity and pollution emissions.This study compares the impacts of single regulation and dual regulation on welfare,using a research-and-development based growth model with heterogeneous firms.Under single regulation,the cleansing effect of trade liberalization could be undermined.Under dual regulation,trade liberalization decreases pollution and improves average productivity whereas decreasing total permits reduces pollution.From the perspective of improving welfare it is desirable to choose dual regulation because trade liberalization can reduce total pollution emissions via the cleansing effect of trade liberalization.

关键词： dual regulation heterogeneous firm Porter hypothesis research and development difficulty trade liberalization

Women’s empowerment and food consumption:Evidence from female-headed households in Tanzania

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Journal of Integrative Agriculture 2024年第2期23卷 457-467页

作者： Mosses Lufuke Xu Tian College of economics and Management Nanjing Agricultural UniversityNanjing 210095China department of economics The University of DodomaDodoma 41218Tanzania College of economics and Management China Agricultural UniversityBeijing 100083China Academy of Global Food economics and Policy China Agricultural UniversityBeijing 100083China

Despite the growing recognition of women’s increasing role in the household and corresponding empowerment programs in sub-Saharan Africa,intensive research on the relationship between women’s influence and household food consumption is minimal.Using the most recent(2017-2018)national household survey data from Tanzania,this study examined the influence of women’s empowerment on household food consumption.First,we compared the monthly consumption of eight food categories between female-headed households(FHHs)and male-headed households(MHHs)using both descriptive statistics and the propensity score matching(PSM)method.Furthermore,we adopted the two-stage Linear Expenditure System and Almost Ideal Demand System model(LES-AIDS)to estimate income and price elasticities for the two household types.The results show that FHHs consume bread and cereals,fish,oils and fats,vegetables,and confectionery(sugar,jam,honey,chocolate,etc.)more than MHHs.Moreover,FHHs have a significantly higher income elasticity of demand for all food groups than MHHs.They are also more price elastic than MHHs in meat,fish,oils,fats,sugar,jam,honey,chocolate,etc.

关键词： women’s empowerment food consumption income elasticity price elasticity

SHA: QoS-Aware Software and Hardware Auto-Tuning for Database Systems

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Journal of Computer Science & Technology 2024年第2期39卷 369-383页

作者：李进陈全唐晓新过敏意 department of Computer Science Shanghai Jiao Tong UniversityShanghai 200240China department of Computer Science and Technology Shanghai University of Finance and EconomicsShanghai 200433China

While databases are widely-used in commercial user-facing services that have stringent quality-of-service(QoS)requirement,it is crucial to ensure their good performance and minimize the hardware usage at the same time.Our investigation shows that the optimal DBMS(database management system)software configuration varies for different user request patterns(i.e.,workloads)and hardware configurations.It is challenging to identify the optimal software and hardware configurations for a database workload,because DBMSs have hundreds of tunable knobs,the effect of tuning a knob depends on other knobs,and the dependency relationship changes under different hardware configurations.In this paper,we propose SHA,a software and hardware auto-tuning system for DBMSs.SHA is comprised of a scaling-based performance predictor,a reinforcement learning(RL)based software tuner,and a QoS-aware resource reallocator.The performance predictor predicts its optimal performance with different hardware configurations and identifies the minimum amount of resources for satisfying its performance requirement.The software tuner fine-tunes the DBMS software knobs to optimize the performance of the workload.The resource reallocator assigns the saved resources to other applications to improve resource utilization without incurring QoS violation of the database workload.Experimental results show that SHA improves the performance of database workloads by 9.9%on average compared with a state-of-the-art solution when the hardware configuration is fixed,and improves 43.2%of resource utilization while ensuring the QoS.

关键词： auto-tuning database configuration joint tuning utilization quality-of-service(QoS)

Cholesky GAS models for large time-varying covariance matrices

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Journal of Management Science and Engineering 2024年第1期9卷 115-142页

作者： Tingguo Zheng Shiqi Ye department of Statistics and Data Science School of EconomicsXiamen UniversityXiamen361005China Wang Yanan Institute for Studies in economics Xiamen UniversityXiamen361005China Paula and Gregory Chow Institute for Studies in economics Xiamen UniversityXiamen361005China

This paper develops a new class of multivariate models for large-dimensional time-varying covariance matrices,called Cholesky generalized autoregressive score(GAS)models,which are based on the Cholesky decomposition of the covariance matrix and assume that the parameters are score-driven.Specifically,two types of score-driven updates are considered:one is closer to the GARCH family,and the other is inspired by the stochastic volatility model.We demonstrate that the models can be estimated equation-wise and are computationally feasible for high-dimensional cases.Moreover,we design an equationwise dynamic model averaging or selection algorithm which simultaneously extracts model and parameter uncertainties,equipped with dynamically estimated model parameters.The simulation results illustrate the superiority of the proposed models.Finally,using a sizeable daily return dataset that includes 124 sectors in the Chinese stock market,two empirical studies with a small sample and a full sample are conducted to verify the advantages of our models.The full sample analysis by a dynamic correlation network documents significant structural changes in the Chinese stock market before and after COVID-19.

关键词： Cholesky decomposition GAS Dynamic conditional correlations Dynamic model averaging

Non-Convex Optimization of Resource Allocation in Fog Computing Using Successive Approximation

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Journal of Systems Science & Complexity 2024年第2期37卷 805-840页

作者： LI Shiyong LIU Huan LI Wenzhe SUN Wei School of economics and Management Yanshan UniversityQinhuangdao 066000China

Fog computing can deliver low delay and advanced IT services to end users with substantially reduced energy consumption.Nevertheless,with soaring demands for resource service and the limited capability of fog nodes,how to allocate and manage fog computing resources properly and stably has become the bottleneck.Therefore,the paper investigates the utility optimization-based resource allocation problem between fog nodes and end users in fog computing.The authors first introduce four types of utility functions due to the diverse tasks executed by end users and build the resource allocation model aiming at utility maximization.Then,for only the elastic tasks,the convex optimization method is applied to obtain the optimal results;for the elastic and inelastic tasks,with the assistance of Jensen’s inequality,the primal non-convex model is approximated to a sequence of equivalent convex optimization problems using successive approximation method.Moreover,a two-layer algorithm is proposed that globally converges to an optimal solution of the original problem.Finally,numerical simulation results demonstrate its superior performance and effectiveness.Comparing with other works,the authors emphasize the analysis for non-convex optimization problems and the diversity of tasks in fog computing resource allocation.

关键词： Fog computing non-convex optimization optimal resource allocation successive approximation method utility function