195 research outputs found
The Future of Carsharing: A System Dynamics Model
L'abstract è presente nell'allegato / the abstract is in the attachmen
Identifying and classifying the factors affecting risk in automobile hull insurance in Iran using fuzzy Delphi method and factor analysis
Automobile hull insurance has attracted much attention due to the high rate of vehicle applications in daily lives. Since purchasing these policies is optional in Iran and their premium rates are set competitively, a competition is formed among the insurance companies for attracting low risk drivers. However, most of the insurers still use comparative rates and pay no or less attention to the factors affecting risk in premium calculations. Considering the importance of fair ratemaking in attracting and maintaining good risks and encouraging bad risks to repent or leave the portfolio, and taking into account the shortcomings of the available databases, this paper focuses on determining and classifying the risk factors affecting premium calculation in automobile hull insurance from the viewpoint of the experts. In this regard, Fuzzy Delphi method is utilized, the factors are classified and the efficiency of the classification is checked by using Confirmatory Factor Analysis (CFA)
The Pandemic Implications for Carsharing: An Italian Context
Carsharing, as an innovative mobility option, can potentially support the urban transition towards a more sustainable mobility system and achieving sustainable development goals. This short communication aims at providing the status of carsharing services in Italy, with a focus on Turin, before and after the COVID-19 pandemic. In this regard, an overview of the role of carsharing in urban traffic is provided. Then, carsharing services in Italy before and after the pandemic are mapped. Accordingly, the implications of the pandemic outbreak for carsharing services are discussed. The provided insights confirm that although carsharing services have been affected by the pandemic, even after returning to normal life, the usage of carsharing is still far below its pre-pandemic level in Italy. Finally, to support sustainable mobility and incentivize using shared mobility services, a research agenda for further research is proposed, targeting the research gaps regarding (i) the factors leading to lower usage of carsharing after the pandemic, (ii) potential solutions and policies to support carsharing services return to their pre-pandemic level and exceeding it, and (iii) examining the impact of provided supports by governments during the pandemic, such as bonuses for purchasing bikes and scooters, on the adoption of carsharing services for the post-pandemic era
The imbalance of food and biofuel markets amid Ukraine-Russia crisis: A systems thinking perspective
The Ukraine war has immensely affected both food and energy systems due to the significant role of Russia in supplying natural gas and fertilizers globally and the extensive contribution of both Russia and Ukraine in exporting grains and oilseeds to the international markets. Hence, the Ukraine-Russia conflict has resulted in a shortage of crops and grains in the food market, especially in Europe, causing speculations if these resources should still be used for biofuel production (1st Generation). However, the International Energy Agency has warned that lowering biofuel mandates could result in rising petroleum demand and supply concerns. In light of these unfolding events, a systems thinking approach is required to monitor and analyze the implications of this crisis for food and biofuel markets as a whole to alleviate the concerns faced and plan sustainably. In this vein, based on the trade-offs between food system elements and the biofuel supply chain, as well as the potential effects of the war on the food and energy systems worldwide, a causal loop diagram is developed in the present work. According to the insights provided, the key to preventing food insecurity and keeping biofuel mandates on an increasing trend simultaneously amid the Ukraine war is to switch from the 1st Generation biofuels to higher generations. This transition would reduce not only the pressure on the food market to move toward zero hunger (SDG 2) but also pave the way to move towards a circular economy and clean and affordable energy (SDG 7) during the post-war er
The effect of L-carnitine on Oocyte Mitochondrial Activity after Cryopreservation
Background: Mitochondria are cellular organelles required for energy production, vital to reproduction, especially oocyte maturation and fertilization. It has been seen that oocyte cryopreservation (OC) can cause mitochondria damage, aggregation of lipid droplets near mitochondria and endoplasmic reticulum, and cryoinjury. In recent studies use of antioxidants such as L- carnitine can increase the number of active mitochondria and decrease intracellular ROS levels. The present study aimed to determine the beneficial effect of L –carnitine on oocyte mitochondrial activity after vitrification.
Materials and Methods: In the present experimental study, 6-8 weeks of female NMRI mice were taken from the Royan Institute of Iran and stimulated with 7.5 IU Pregnant Mare Serum Gonadotrophin (PMSG) and 10 IU of human chorionic gonadotropin (HCG) after 48 hours was injected. After stimulation, oocytes were collected, and MII oocytes were selected. A two-step vitrification procedure was done, and 0.6mg/ml of L –carnitine was added to both ES and VS mediums. After two weeks, oocyte thawing was performed, intracellular GSH level was also measured mitochondrial membrane potential was measured. Captured images were analyzed by J software (Version 1.40; and obtained data were analyzed using SPSS Ver.20.
Results: Average difference in intracytoplasmic GSH level in the study group was significantly higher than the control group (P<0.001). So, L –carnitine could successfully increase the oocyte intracytoplasmic GSH level. Also, it has been seen that the LC supplement could successfully grow oocyte mitochondrial function and subsequent mitochondrial membrane potentials(P<0.001).
Conclusion: Adding LC to the cryopreservation media could increase mitochondrial activity, GSH level, and mitochondrial membrane potentials. Adding LC to the cryopreservation could enjoy the beneficial effect of L –carnitine on oocyte mitochondrial activity after vitrification and minimize mitochondrial damage and boost oocyte quality which can lead to successful fertilization and embryo growth
Conceptualizing environmental effects of carsharing services: A system thinking approach
Emerging carsharing services and their interconnections with other modes of urban transport, regulations, car manufacturing and population have affected the dynamics of energy consumption, environmental pollution and greenhouse gas emission within a complex system. However, although some aspects of environmental impacts of transport sector have been investigated in the literature, well-deserved studies on the environmental effects of carsharing services following a system thinking approach is missing. This research aims at providing a comprehensive conceptual framework to systematize the interconnections between carsharing services and their environmental effects. To do this, system dynamics (SD) modeling, as a tool to simulate complex and dynamic systems, is applied and the proposed framework model is illustrated by using a causal-loop diagram (CLD). Along with analyzing the main identified causal loops within the presented CLD, relevant strategies are proposed to reduce the negative environmental effects associated with the carsharing services, considering the whole lifecycle of a shared vehicle. The proposed framework can help environment policy makers and shared mobility practitioners in long-term strategic decision-making. Moreover, it can be applied by the researchers as a basis for future research, not only for SD modeling but also other simulation and analysis structures
Sustainability and the Sharing Economy: Modelling the Interconnections
Advances in technology have led to the rise of sharing economy, which has become a strong competitor for capitalist companies in various fields. In addition to the economic aspects of such phenomenon, the activities of the sharing economy can have social and environmental impacts, which brings sustainability pillars into mind. In this paper, based on the system thinking approach, a causal loop diagram that is a part of system dynamics modelling is applied for visualizing the relationships between sharing economy and sustainability pillars. The reinforcing and balancing loops modelled show the dynamics in the system, which help decision makers to gain a deeper and more accurate understanding of the current and potential future mutual interactions between the sharing economy and sustainability
Penetrating Keratoplasty versus Deep Anterior Lamellar Keratoplasty for Keratoconus: A Systematic Review and Meta-analysis
Keratoconus is the most common form of primary corneal thinning. Different methods have been suggested to deal with the condition, including glasses, contact lenses, and surgical interventions, like penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK), well-known methods of the latter. This study was conducted to compare the outcomes and side effects of the two mentioned keratoplasty techniques. First, we systematically reviewed all original articles studies on PubMed, Scopus, Web of Science, and Embase. Then, the extracted data were pooled and meta-analyzed on each of the intended outcomes. A total of 30 studies were included in which PKP was more commonly performed compared to DALK. We found that adverse outcomes consisting of cataracts, graft rejection, graft failure, High-IOP, and corneal infection, were all more common findings in the PKP groups compared to the DALK groups. However, only for the high-IOP, cataracts, and graft rejection, the analysis of the extracted results demonstrated statistical significance. Overall, the DALK groups demonstrated significantly better results when considering the improvement levels by measuring the Endothelial Cell Count (ECC) and Spherical Equivalent (SE). In addition, though statistically insignificant, the Central Corneal Thickness(CCT), Best Corrected Visual Acuity(BCVA), Topographic Cylinder(TC), Refractive Cylinder values were greater in the PKP groups. Based on our study and with its limitations in mind, we can conclude that DALK can be a relatively safer and more effective procedure. Though, a larger number of high-standard randomized clinical trials still need to be conveyed for more definite conclusions
Factors Affecting the Greenhouse Owners’ Attitude toward Sustainable Agriculture in Zanjan Province
Due to the low compliance of greenhouse production with the principles of sustainable agriculture, a meaningful effort in this regard needs to be done. One of the important factors affecting the success of future planning is the positive attitude of greenhouse owners toward sustainable agriculture. The purpose of this descriptive- correlational study was to investigate factors affecting greenhouse owners’ attitude toward sustainable agriculture. The validity of the questionnaire was verified by a panel of experts in the related field and to obtain its reliability, calculated alpha Cronbach coefficient was higher than 0.75 for different parts. The statistical population consisted all greenhouse owners in Zanjan province (N=80) and based on Krejci and Morgan sampling Table and using randomized sampling method 66 greenhouse owners selected. Results showed that majority of greenhouse owner use moderately of information channels and mass media. The majority of greenhouse owners (59.6 percent) had a medium level of knowledge regarding sustainable agriculture and Majority of them (73.7 percent) had a positive attitude toward sustainable agriculture. Correlation coefficient showed that greenhouse owners’ attitude had a positive meaningful correlation with information using level, income from the greenhouse, number of educational classes and their job satisfaction but a negative meaningful correlation with the number of household members participating in the activity. Regression analysis revealed that five variable of information using level, the number of household members participating in activity, knowledge and daily time spending in the greenhouse were explained 55.4 percent of greenhouse owners’ attitude toward sustainable agriculture
Digitally enabled food sharing platforms towards effective waste management in a circular economy:A system dynamics simulation model
As a solution to tackle the food waste (FW) challenge, digitally enabled food sharing platforms (FSPs) are emerging as FW warriors and anti-waste social movements. Despite the rapidly growing number of users, the amount of FW prevented per user in these platforms is relatively low. Hence, the real contribution of FSPs to the circular economy (CE) by preventing FW is still blurred. To fill this gap, a System Dynamics simulation model is developed in this research to unfold how people adopt such platforms over time, and how such platforms contribute to the CE through FW prevention. The model is used to simulate the adoption and performance of Italy’s Too Good To Go (TGTG) platform spanning 2015-2060 as a reference case. The results show that although TGTG is a successful FSP in terms of adoption, it can still significantly improve in terms of performance. Besides, while the current TGTG’s marketing strategy is effective, knowledge-enhancing activities should be strengthened to improve performance. Hence, this research recommends a winning policy, which can reduce approximately 3% of the total FW generated at the country level (Italy) in 2060, a significant contribution to the CE transition
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