bluuebunny/crossref_metadata_2025 huggingface dataset:
Imagined Embedding(s): Young People’s Reasons for Moving to Norway
Authors: Ardic Tuba
Published: May 2023

There has been a plethora of scholarly work which examines the motivational and lingering factors of youth mobilities but there has not been a sufficient number of scholarly articles that explain specifically why Norway is a destination for youth, with a few exceptions. This paper focuses on young people who move to Norway for employment reasons. Six interviews were chosen via a purposeful sampling from a sample of 15 interviewees, who moved to Norway. The interviews were transcribed and were analysed via thematic analysis. As a result of the thematic analysis, it is observed that imagined embedding(s), a theorisation to explain the motivations to choose a destination place, can be applied to these cases. I contribute to the literature by applying imagined embedding(s) to the motivations for moving abroad, in this case to Norway for young people in mobility. Since most of the work examines the embedding(s) during mobility, my focus will be on the period before mobility and the initial period of mobility. This research proves that the economic reasons for movement are almost always coupled with other more intrinsic and non-economic motives and imagination(s) of a place.
Relationship between Bioelectrical Impedance Phase Angle and Upper and Lower Limb Muscle Strength in Athletes from Several Sports: A Systematic Review with Meta-Analysis
Authors: Cirillo Everton , Pompeo Alberto , Cirillo Fabiane Tavares , Vilaça-Alves José , Costa Pablo , Ramirez-Campillo Rodrigo , Dourado Antonio Carlos , Afonso José , Casanova Filipe
Published: May 2023

The phase angle (PhA) of bioelectrical impedance is determined by primary factors such as age, body mass index and sex. The researchers’ interest in applying PhA to better understand the skeletal muscle property and ability has grown, but the results are still heterogeneous. This systematic review with a meta-analysis aimed to examine the existence of the relationship between PhA and muscle strength in athletes. The data sources used were PubMed, Scielo, Scopus, SPORTDiscus, and Web of Science and the study eligibility criteria were based on the PECOS. The searches identified 846 titles. From those, thirteen articles were eligible. Results showed a positive correlation between PhA and lower limb strength (r = 0.691 [95% CI 0.249 to 0.895]; p = 0.005), while no meta-analysis was possible for the relationships between PhA and lower limb strength. Furthermore, GRADE shows very low certainty of evidence. In conclusion, it was found that most studies showed a positive correlation between PhA and vertical jump or handgrip strength. The meta-analysis showed the relationship between PhA and vertical jump, however, little is known for the upper limbs as was not possible to perform a meta-analysis, and for the lower limbs we performed it with four studies and only with vertical jump.
How Cities Study Quality of Life and Use This Information: Results of an Empirical Study
Authors: Ligarski Mariusz J. , Owczarek Tomasz
Published: May 2023

Quality-of-life surveys can play an important role in obtaining information for sustainable urban development. To collect such data, a proper understanding and preparation of these surveys by city offices are needed. The research team developed a research concept to investigate how city offices conduct quality-of-life surveys and use this information. The paper presents the results of a survey conducted on a sample of all cities with a population over 50,000 in Poland. The surveyed cities were divided into two groups, cities that conduct formalized quality-of-life surveys and cities that do not conduct such surveys. The survey examined how cities understand the areas that affect quality of life and how they determine the influence of the local government on the quality of life of residents. Similarities and differences were considered in the two groups of offices surveyed. The necessity of including a large number of areas that affect the quality of life in the surveys conducted by cities was emphasized. Such an approach provides an opportunity to collect a variety of data that can be used for the city’s needs. It was found that cities conducting formalized quality-of-life surveys stand definitely higher in determining the impact of the local government on the quality of life of residents.
Demand for and Supply of Pulses and Oil Crops in Bangladesh: A Strategic Projection for These Food Item Outlooks by 2030 and 2050
Authors: Bokhtiar Shaikh Mohammad , Islam Sheikh Md. Fakhrul , Molla Md. Mosharraf Uddin , Salam Md. Abdus , Rashid Md. Abdur
Published: May 2023

The food items, such as pulses and oil crops, are influential means of nutritional security for the people in Bangladesh. Pulses are widely called here as an alternative to meat for poor households. The study aimed to predict productivity and national demand of pulses and oil crops in Bangladesh by 2030 and 2050, minimizing the supply and demand gaps of these crops. Using the ARIMA model developed by Box and Jenkins, the current study projected Bangladesh’s pulse and oil crop demand and supply for the years 2030 and 2050. The projections showed that the total demand for pulses in 2030 will be 17.9 lakh MT and further increased to 19.5 lakh MT in 2050. The deficit in the supply of pulses will be 12.36 lakh MT in 2030 and 9.26 lakh MT in 2050 although the shortage of pulses will disappear as a result of productivity improvements and innovations. Per capita consumption of edible oil in Bangladesh is 20–22 g per day. The majority of domestically produced soybean (5% of total demand) is used in the feed industries, while edible oil from soybean depends on import. The supply of mustard oil is predicted to be in deficit by 0.30 lakh MT in 2030 and 1.68 lakh MT in 2050. Nevertheless, the estimates also warn that supply of these food items could be threatened due to climate changes. In facing future challenges, supportive government policy and substantial investment in research and extension should be given priority for technological innovation and productivity improvement. Government also needs to develop a strategic import substitution policy for higher production of these crop and storage facilities.
Experimental Study of MICP-Solidified Calcareous Sand Based on Ambient Temperature Variation in the South China Sea
Authors: Hu Jun , Yang Yufei , Zhou Yuxuan , Xiang Hui , Wei Kai
Published: May 2023

With the continuous advancement of the construction of the Hainan Free Trade Port and Island Reef Project, deploying Microbial Induced Calcium Carbonate Precipitation (MICP technology) for related research on the temperature range in this area would be of great significance. MICP technology is an innovative and sustainable new soil reinforcement technology that uses the metabolic activity of specific bacteria to produce calcium carbonate precipitation (CaCO3) to connect loose soil. A few previous studies reporting on the applications of MICP technology in different temperature environments drew different conclusions. Therefore, this study involved MICP sand column reinforcement tests at ambient temperatures of 20 °C, room temperature, 30 °C, and 40 °C. The reinforcement effect was evaluated using indicators such as CaCO3 generation rate, Ca2+ conversion rate, bacterial adhesion rate, water absorption rate, and unconfined compressive strength, providing a reference basis for the future applications of MICP technology to island and reef engineering construction. The results showed that, with an increase of temperature from 20 °C to 40 °C, the CaCO3 production rate, Ca2+ conversion rate, and unconfined compressive strength showed a trend of first increasing and then decreasing; the UCS was 548 KPa at 20 °C and 2276.67 KPa at 30 °C; the water absorption rate at 20 °C was 25.32, which decreased continuously with increasing temperature, and reached 21.49 at 40 °C; and the bacterial adhesion rate also continued to rise in the range of 20 °C to 40 °C, from 10.91 to 28.44. The increase in temperature had an impact on the physiological state of bacterial cells. A scanning electron microscope test shows that CaCO3 crystal forms generated under different temperature environments were different, and the CaCO3 mineral deposits generated during MICP reinforcement at 30 °C were denser. Fewer gaps were present between adjacent sand particles, and the bond was tight, which served better as a bridge. The strength of the solidified sample was also higher. The annual average temperature of the South China Sea is about 30 °C. The findings of this experiment provide feasibility and sustainable development for MICP project reinforcement in the South China Sea.
Characteristics of Tetracycline Adsorption on Commercial Biochar from Synthetic and Real Wastewater in Batch and Continuous Operations: Study of Removal Mechanisms, Isotherms, Kinetics, Thermodynamics, and Desorption
Authors: Rizkallah Basem M. , Galal Mona M. , Matta Minerva E.
Published: May 2023

Tetracycline (TC) is an antibiotic commonly used to treat bacterial infections. It is detected in wastewater and is considered an emerging contaminant that must be removed before discharge to water bodies. This study examined its adsorption on commercial biochar, a low-cost and sustainable adsorbent produced from the agricultural waste of citrus trees, in both batch and continuous flow systems and from synthetic and real wastewater. The surface area of the biochar was determined using Brunauer–Emmett–Teller (BET) analysis to be 364.903 m2/g. Batch experiments were conducted using biochar doses of 1.5–3.5 g/50 mL; initial TC concentrations of 30–90 mg/L; pH values of 4, 7, and 11; and temperatures of 20, 30, and 40 °C. The results show that TC was successfully removed from both synthetic and real wastewater at removal rates reaching 87% at pH = 4, an adsorbent dose of 3.5 g/50 mL, an initial adsorbate concentration of 90 mg/L, and a temperature of 20 °C in batch experiments for synthetic wastewater and at removal rates reaching 95% for real wastewater. Thermodynamic parameter estimation results revealed that the process is exothermic and spontaneous, while kinetic results showed that adsorption is a multi-step process. TC adsorption on biochar was found to be a physical process. In continuous-mode operation, removal reached 37% at a bed depth of 3 cm. Scanning electron microscopy (SEM) morphologies and Fourier-transform infrared (FTIR) spectroscopy confirmed the occurrence of adsorption.
The Effect of Sustainable Human Resource Management Practices on Customer Satisfaction, Service Quality, and Institutional Performance in Hotel Businesses
Authors: Papademetriou Christos , Anastasiadou Sofia , Papalexandris Stylianos
Published: May 2023

The purpose of the current research seeks to explore the influence of sustainable Human Resource Management (HRM) practices on customer satisfaction, service quality, and institutional performance in inner-city hotel businesses. The information was gathered by studying Cypriot inner-city hotels. A quantitative method was used to gather data from HRM managers, staff, and patrons at every inner-city hotel under study. The questionnaires were specifically employed by the researchers. Based on the findings of this study, human resource management techniques have a substantial effect on customer satisfaction. The most important relationship was discovered between customer satisfaction and institutional performance, which is an important result. This finding has tremendous importance since it is the first time that it has been demonstrated in a study pertaining to the inner-city hotel business. Customer satisfaction is influenced by both HRM and service quality practices. Ultimately, this research supports the close association between HRM practices and hotel performance. Both human resource management methods and service quality practices have shown their impact on client happiness. Lastly, the research provides evidence for the close relationship between hotel performance and HRM practices.
Does Perceived Sustainability Affect the Customer Responses toward the Brands? Role of Customer Engagement as a Mediator
Authors: Khan Imran , Fatma Mobin
Published: May 2023

The notion of sustainability has received increased attention among marketers, and in theory. Though studies have discussed the crucial role of sustainable practices in shaping consumer responses, the role that perceived sustainability plays in engaging customers, and its effect on customer responses has received less attention. The study aims to determine the effect of perceived sustainability on customer loyalty and trust through the mediation of customer engagement. 330 responses were collected to test the proposed model. Structural equation modeling was used to test the hypothesis. The main findings of the study revealed a significant and positive effect of perceived sustainability on customer loyalty and trust. Further, we found that customer engagement acts as mediator between perceived sustainability and trust association. However, the results indicate that customer engagement does not mediate the link between perceived sustainability and loyalty. Extending sustainability and customer engagement literature, the study presents empirical evidence towards the direct effect of perceived sustainability on customer loyalty and trust as well as the indirect effect on trust via customer engagement. The study suggests practitioners develop a strategy that could incorporate sustainability initiatives in marketing programs because these initiatives may engage customers and affect their responses (i.e., loyalty and trust).
A Multi-Agent Reinforcement Learning Approach to the Dynamic Job Shop Scheduling Problem
Authors: İnal Ali Fırat , Sel Çağrı , Aktepe Adnan , Türker Ahmet Kürşad , Ersöz Süleyman
Published: May 2023

In a production environment, scheduling decides job and machine allocations and the operation sequence. In a job shop production system, the wide variety of jobs, complex routes, and real-life events becomes challenging for scheduling activities. New, unexpected events disrupt the production schedule and require dynamic scheduling updates to the production schedule on an event-based basis. To solve the dynamic scheduling problem, we propose a multi-agent system with reinforcement learning aimed at the minimization of tardiness and flow time to improve the dynamic scheduling techniques. The performance of the proposed multi-agent system is compared with the first-in–first-out, shortest processing time, and earliest due date dispatching rules in terms of the minimization of tardy jobs, mean tardiness, maximum tardiness, mean earliness, maximum earliness, mean flow time, maximum flow time, work in process, and makespan. Five scenarios are generated with different arrival intervals of the jobs to the job shop production system. The results of the experiments, performed for the 3 × 3, 5 × 5, and 10 × 10 problem sizes, show that our multi-agent system overperforms compared to the dispatching rules as the workload of the job shop increases. Under a heavy workload, the proposed multi-agent system gives the best results for five performance criteria, which are the proportion of tardy jobs, mean tardiness, maximum tardiness, mean flow time, and maximum flow time.
Differential Expression of Antioxidant Enzymes in Chlorine-Resistant Acinetobacter and Serratia spp. Isolated from Water Distribution Sites in Mumbai: A Study on Mechanisms of Chlorine Resistance for Sustainable Water Treatment Strategies
Authors: Jathar Santosh , Dakhni Sanabil , Shinde Disha , Fernandes Abigail , Jha Pamela , Desai Neetin , Sonawane Tareeka , Jobby Renitta
Published: May 2023

Chlorination is a widely used process for disinfecting drinking water, but the emergence of chlorine-resistant bacteria has become a significant concern. While previous research has focused on identifying chlorine-resistant organisms, there has been limited investigation into the mechanisms behind chlorine resistance. Some bacterial isolates that display resistance to chlorine treatment may protect themselves using various mechanisms, including biofilm production, antibiotic resistance, horizontal transfer of antibiotic resistance genes, or producing antioxidant enzymes. Given that chlorination employs hypochlorous acid (HOCl), which is an extremely potent oxidizing agent, the most critical mechanism to investigate is antioxidant enzymes. This study investigated the antioxidant profile of eight chlorine-resistant isolates (three of the Serratia sp. and five of the Acinetobacter) after chlorine exposure. The profiles, both between and within species, were noticeably different. Among the isolates, Acinetobacter junii NA 3-2 showed a significant increase in the specific activity of superoxide dismutase, catalase, and ascorbate peroxidase after exposure to 20 ppm chlorine. In the guaiacol peroxidase (GPX) assay, only isolates belonging to Serratia marcescens showed GPX activity, and Serratia marcescens 3929-1 showed significant increase after exposure to 20 ppm of chlorine. None of the isolates belonging to Acinetobacter spp. showed GPX activity. Additionally, almost all control samples exhibited some enzyme activity, which may explain their survival against chlorine treatment in reservoirs. Principal component analysis revealed no strain-dependent similarities, while the balance of scavenging enzymes changed, as demonstrated in the heat map. Thus, this study suggests that antioxidant enzymes may be one mechanism of protection for some bacterial species against oxidative stress from chlorination, resulting in chlorine resistance. Understanding the mechanism of chlorine resistance is critical to identifying potential solutions. This study highlights the need to consider more modern approaches to disinfecting drinking water.
Green Credit Policy, Environmental Investment, and Green Innovation: Quasi-Natural Experimental Evidence from China
Authors: Xu Zhiliang , Xu Changxin , Li Yun
Published: May 2023

In order to explore whether green credit policy can guide the green transformation of heavily polluting firms, we examine the influence of green credit policy on green innovation. Further, we analyze the mediating effect of environmental investment and the moderating effect of type of ownership and green finance development level in this relationship. Findings from the DID model indicate that the Green Credit Guidelines led to a significant increase in green innovation at heavily polluting enterprises, both quantitatively and qualitatively, with environmental investment acting as partial mediators. Further, the positive influence of green credit policy is more substantial in state-owned firms and in regions with high levels of green finance development. Findings are robust and remain valid after different sensitivity tests, including the improved PSM-DID model and the elimination of interference from some samples to address the sample selection bias existing in the DID model.
Driving Change towards Sustainability in Public Bodies and Civil Society Organisations: Expert Interviews with UK Practitioners
Authors: Rieg Nicola Andreij , Gatersleben Birgitta , Christie Ian
Published: May 2023

While public bodies and civil society organisations play an important role in the transition towards a more sustainable society, there has been very limited research on how to make these institutions more sustainable. Therefore, the purpose of this study is to generate insights on processes and patterns of change towards sustainability, and to identify effective practices that might be transferred and adapted to different institutional contexts. The research followed an organisational change framework and a qualitative exploratory design. Six semi-structured interviews were conducted with experienced sustainability practitioners working at leading organisations in the UK. Thematic analysis of the data revealed three overarching themes: knowledge and reflection, support and engagement, and driving and enabling change. From this, a framework for effective practice was developed, highlighting the importance of (i) explicitly linking organisational understanding to working practices through frequent and deliberate reflection; (ii) developing a support base that provides expertise and legitimacy; and (iii) using context-specific strategies for implementing planned changes, as well as supporting emergent change throughout organisational sub-systems.
Optimal Reutilization Strategy for a Shipbuilder under the Carbon Quota Policy
Authors: Zhang Chonghao , Zhang Yuan , Huang Zongsheng
Published: May 2023

Reducing carbon emissions is crucial for humanity. Recently, the International Maritime Organization has set carbon emission quotas to limit the extensive carbon emissions from the marine industry. This paper examines how shipbuilders can adopt the rebuilding of decommissioned ships to reduce carbon emissions and also make more profits. Incorporating the carbon emission quota policy, we formulate the dynamic rebuilding model of decommissioned ships and derive the optimal rebuilding and pricing control strategies for the shipbuilder. We investigate the evolutionary dynamics as well as the impact of carbon quotas and carbon emission savings on shipbuilder’s strategies. The study’s findings suggest that shipbuilders have the potential to improve their profitability while also contributing to energy conservation and emission reduction. This can be achieved through the implementation of technological innovations aimed at reducing carbon emissions from their production activities. The government has a crucial role to play in regulating and managing shipbuilders. In cases where the cost per unit of carbon quota is deemed excessively high, it may be necessary to establish appropriate regulations that prevent shipbuilders from directly benefiting from the trade of carbon quotas. This approach can also help ensure the positive development of the carbon trading market.
Evolutionary Game Study of Waste Separation Policy in the Context of the “Double Carbon” Target
Authors: Jiang Yanyan , Zhang Lichi , Wu Junmin
Published: May 2023

Research on waste separation promotion policies is of great theoretical and practical significance for the universal implementation of the domestic waste separation system. This paper constructs a non-cooperative tripartite evolutionary game model that includes central command, local deployment, and enterprise performance. An evolutionary game approach was used to analyze the strategic choices of the central government, local government, and separation enterprises in waste separation promotion, and this study investigated the factors influencing the evolution of these choices using numerical simulations. The findings indicated the following: central government, local governments, and separation enterprises are affected differently by their respective willingness to participate; the behavior of separation enterprises is less influenced by the central government’s and local governments’ willingness to participate and is primarily influenced by market factors, whereas local government is more influenced by the central government’s willingness to participate; and local government and classification enterprises are affected differently by their respective willingness to participate. While separation firms are more susceptible to the cost-sharing, income, and revenue distribution coefficient, local governments are more responsive to policy support. The promotion of waste separation in China requires strengthened centralized waste management to avoid the failure of local waste separation, broadening of the scope of central funding incentives and establishing local separation compensation mechanisms, clarifying local waste separation performance responsibilities and new waste tax collection standards, supporting separation enterprises’ technological innovation and guiding public participation in waste separation, creating an environment for waste separation, and deepening the study of waste separation accordingly.
Numerical Study of the Internal Fluid Dynamics of Draft Tube in Seawater Pumped Storage Hydropower Plant
Authors: Hu Jianyong , Wang Qingbo , Meng Zhenzhu , Song Hongge , Chen Bowen , Shen Hui
Published: May 2023

Pumped storage hydropower plants are renewable energy systems that are effective in saving energy and solving electricity peak-on shortage. Seawater pumped storage hydropower plants are a novel type of pumped storage hydropower plant specifically supplying electric power for ocean islands with the support of solar energy and wind energy. Compared with traditional pumped storage hydropower plants that are constructed on the mainland, seawater pumped storage hydropower plants should take the influence of the complex marine environment, such as extreme waves and winds, into consideration. Taking the characteristics of waves near islands in the East China Sea as an example, we explored the transient hydraulic characteristics in the draft tube of a pump turbine under wave disturbance using a sliding grid interface and the detached eddy simulation (DES) turbulence model. By analyzing the characteristics of unsteady flow in the draft tube, the vortex characteristics under the Q criterion, the frequency characteristics of the pressure pulsation, the evolution law of the internal fluid, and the propagation law of the pressure pulsation were explored. For the situation without wave disturbance, an obvious eccentric vortex in the straight cone section of the draft tube was observed in the case where the opening of the guide vane was small. With the increase in the opening of the guide vane, the eccentric vortex gradually dissipated. For the situation with wave disturbance, the main frequency of the draft tube equaled the frequency of the wave disturbance, the maximum pressure pulsation at the selected monitoring points increased 5 to 15 times, and the superposition of the wave pressure pulsation signals and the draft tube pressure pulsation produced more low-frequency, high-amplitude pressure pulsation signals. Even though the pressure pulsation frequency spectrum varied a lot, the frequency domain of the pressure pulsation without wave disturbance still existed. In addition, the wave disturbance merely varied with the pressure of the draft tube. The influence of wave disturbance on the pressure distribution in the draft tube was relatively small. The results can provide a reference for the operation of seawater pumped storage hydropower plants.
A Single-Averaged Model for the Solar Radiation Pressure Applied to Space Debris Mitigation Using a Solar Sail
Authors: Carvalho J. P. S. , Cardoso dos Santos J. , Lima J. S. , Brejão L. F. , Prado A. F. B. A.
Published: May 2023

Several non-functional objects are orbiting around the Earth and they are called space debris. In this work, we investigate the process of space debris mitigation from the GEO region using a solar sail. The acceleration induced by the solar radiation pressure (SRP) is the most relevant perturbation for objects in orbit around the Earth with a high area-to-mass ratio (A/m). We consider the single-averaged SRP model with the Sun in an elliptical and inclined orbit. In addition to the SRP effect, the orbital evolution of space debris is analyzed considering the perturbations due to the Earth’s flattening and third-body perturbations in the dynamical system. The idea is to use the solar sail as a propulsion system using the Sun itself as a clean and abundant energy source so that it can remove space debris from the geostationary orbit and also contribute to the sustainability of space exploration. Using averaged dynamical maps as a tool, the numerical simulations show that the solar sail contributes strongly to exciting the eccentricity of the space debris, causing its reentry into Earth’s atmosphere. To perform the numerical simulations, we consider data from real space debris. We also show that the solar sail can be used to remove space debris for a graveyard orbit. In this way, the solar sail can work as a clean and sustainable space-debris-removal mechanism. Finally, we show that the convenient choice of the argument of perigee and the longitude of the ascending node might contribute to amplify the growth of eccentricity. It is also shown that solar radiation pressure destroys the symmetry of the orbits that can be observed in keplerian orbits, so all the orbits will be asymmetric when considering the presence of this force.
Enhanced Dispersion Monitoring Structures Based on Modified Successive Sampling: Application to Fertilizer Production Process
Authors: Hyder Mehvish , Raza Syed Muhammad Muslim , Mahmood Tahir , Abbas Nasir
Published: May 2023

In this era of Industry 4.0, efficient and affordable monitoring solutions are needed for the surveillance of manufacturing/service operations. In general, memory-type control charts outperform memoryless control charts when it comes to determining the changes in location and dispersion parameters of symmetrically distributed processes. Before monitoring the process location, it is essential to monitor the process dispersion, since the latter presumes that the process variance remains stable. In practice, the modified successive sampling (MSS) mechanism is preferred over simple random sampling for its cost-effectiveness and efficiency. This study was designed in order to propose moving average and double moving average control charts based on the MSS mechanism for monitoring the dispersion parameter. The performance of the proposed charts is evaluated using run-length measures, and a comparison is made with an existing control chart based on MSS and repetitive sampling. Furthermore, the application of the designed moving and double moving average charts is demonstrated using a case study related to fertilizer production. It is observed that the proposed double moving average control chart performs better than the other control charts designed under the MSS and repetitive sampling schemes.
The Existence of Odd Symmetric Periodic Solutions in the Generalized Elliptic Sitnikov (N+1)-Body Problem
Authors: Cheng Xuhua , Liu Baoting
Published: May 2023

In this paper, we study the existence of the families of odd symmetric periodic solutions in the generalized elliptic Sitnikov (N+1)-body problem for all values of the eccentricity e∈[0,1) using the global continuation method. First, we obtain the properties of the period of the solution of the corresponding autonomous equation (eccentricity e=0) using elliptic functions. Then, according to these properties and the global continuation method of the zeros of a function depending on one parameter, we derive the existence of odd periodic solutions for all e∈[0,1). It is shown that the temporal frequencies of period solutions depend on the total mass λ (or the number N) of the primaries in a delicate way.
Quantization of Constrained Systems as Dirac First Class versus Second Class: A Toy Model and Its Implications
Authors: Ita Eyo Eyo , Soo Chopin , Tan Abraham
Published: May 2023

A toy model (suggested by Klauder) was analyzed from the perspective of first-class and second-class Dirac constrained systems. First-class constraints are often associated with the existence of important gauge symmetries in a system. A comparison was made by turning a first-class system into a second-class system with the introduction of suitable auxiliary conditions. The links between Dirac’s system of constraints, the Faddeev–Popov canonical functional integral method and the Maskawa–Nakajima procedure for reducing the phase space are explicitly illustrated. The model reveals stark contrasts and physically distinguishable results between first and second-class routes. Physically relevant systems such as the relativistic point particle and electrodynamics are briefly recapped. Besides its pedagogical value, the article also advocates the route of rendering first-class systems into second-class systems prior to quantization. Second-class systems lead to a well-defined reduced phase space and physical observables; an absence of inconsistencies in the closure of quantum constraint algebra; and the consistent promotion of fundamental Dirac brackets to quantum commutators. As first-class systems can be turned into well-defined second-class ones, this has implications for the soundness of the “Dirac quantization” of first-class constrained systems by the simple promotion of Poisson brackets, rather than Dirac brackets, to commutators without proceeding through second-class procedures.
Topology Optimization of Continuum Structures Based on Binary Hunter-Prey Optimization Algorithm
Authors: Zhao Zhuanzhe , Rui Yujian , Liu Yongming , Liu Zhibo , Tu Zhijian
Published: May 2023

According to BESO’s principle of binarizing continuous design variables and the excellent performance of the standard HPO algorithm in terms of solving continuous optimization problems, a discrete binary Hunter-prey optimization algorithm is introduced to construct an efficient topology optimization model. It was used to solve the problems that the BESO method of topology optimization has, such as easily falling into the local optimal value and being unable to obtain the optimal topology configuration; the metaheuristic algorithm was able to solve the topology optimization model’s low computational efficiency and could easily produce intermediate elements and unclear boundaries. Firstly, the BHPO algorithm was constructed by discrete binary processing using the s-shape transformation function. Secondly, BHPO-BESO topology optimization theory was established by combining the BHPO algorithm with BESO topology optimization. Using the sensitivity information of the objective function and the updated principle of the meta-heuristic of the BHPO algorithm, a semi-random search for the optimal topology configuration was carried out. Finally, numerical simulation experiments were conducted by using the three typical examples of the cantilever beam, simply supported beam, and clamping beam as optimization objects and the results were compared with the solution results of BESO topology optimization. The experimental results showed that compared with BESO, BHPO-BESO could find the optimal topology configuration with lower compliance and maximum stiffness, and it has higher computational efficiency, which can solve the above problems.
Managing the Lean–Agile Paradox in Complex Environments
Authors: Furlan Andrea , Grandinetti Roberto , De Toni Alberto F.
Published: May 2023

The decision to incrementally improve existing processes and products or introduce breakthrough innovations depends on the context a company is facing. In situations where problems are known, it is better to incrementally improve, while in complex situations where problems are not known, a probe-sense-respond approach based on experimentation and the exploration of new solutions is preferable. Lean management adapts well to the first type of context, while agile management fits the second type of context. However, organizations must increasingly consider both approaches and become ambidextrous by introducing incremental improvements and breakthrough innovations simultaneously. This requires embracing the paradox between exploiting and exploring, adopting a new leadership mindset, and dual strategic, organizational, and behavioral models. This paper proposed a framework to implement lean and agile approaches simultaneously using the paradox theory to justify and manage this co-existence. This framework is threefold. First, managers need to differentiate between lean and agile, finding ways of keeping the two approaches separated. Second, lean and agile should be integrated so that synergies between the two approaches can be generated. Finally, managers need to achieve a dynamic equilibrium over time between lean and agile. Contributions to the theory and practice of this approach were discussed.
A Sensitive Response Index Selection for Rapid Assessment of Heavy Metals Toxicity to the Photosynthesis of Chlorella pyrenoidosa Based on Rapid Chlorophyll Fluorescence Induction Kinetics
Authors: Gan Tingting , Yin Gaofang , Zhao Nanjing , Tan Xiaoxuan , Wang Ying
Published: May 2023

Heavy metals as toxic pollutants have important impacts on the photosynthesis of microalgae, thus seriously threatening the normal material circulation and energy flow of the aquatic ecosystem. In order to rapidly and sensitively detect the toxicity of heavy metals to microalgal photosynthesis, in this study, the effects of four typical toxic heavy metals, chromium (Cr(VI)), cadmium (Cd), mercury (Hg), and copper (Cu), on nine photosynthetic fluorescence parameters (φPo, ΨEo, φEo, δRo, ΨRo, φRo, FV/FO, PIABS, and Sm) derived from the chlorophyll fluorescence rise kinetics (OJIP) curve of microalga Chlorella pyrenoidosa, were investigated based on the chlorophyll fluorescence induction kinetics technique. By analyzing the change trends of each parameter with the concentrations of the four heavy metals, we found that compared with other parameters, φPo (maximum photochemical quantum yield of photosystem II), FV/FO (photochemical parameter of photosystem II), PIABS (photosynthetic performance index), and Sm (normalized area of the OJIP curve) demonstrated the same monotonic change characteristics with an increase in concentration of each heavy metal, indicating that these four parameters could be used as response indexes to quantitatively detect the toxicity of heavy metals. By further comparing the response performances of φPo, FV/FO, PIABS, and Sm to Cr(VI), Cd, Hg, and Cu, the results indicated that whether it was analyzed from the lowest observed effect concentration (LOEC), the influence degree by equal concentration of heavy metal, the 10% effective concentration (EC10), or the median effective concentration (EC50), the response sensitivities of PIABS to each heavy metal were all significantly superior to those of φRo, FV/FO, and Sm. Thus, PIABS was the most suitable response index for sensitive detection of heavy metals toxicity. Using PIABS as a response index to compare the toxicity of Cr(VI), Cd, Hg, and Cu to C. pyrenoidosa photosynthesis within 4 h by EC50 values, the results indicated that Hg was the most toxic, while Cr(VI) toxicity was the lowest. This study provides a sensitive response index for rapidly detecting the toxicity of heavy metals to microalgae based on the chlorophyll fluorescence induction kinetics technique.
Combined Toxicities of Di-Butyl Phthalate and Polyethylene Terephthalate to Zebrafish Embryos
Authors: Zhang Qiang , Ma Wenjie , Zhu Jingmin
Published: May 2023

The increasing concern for the ecological risks of microplastics (MPs) as carriers of hydrophobic organic contaminants is evident. Di-butyl phthalate (DBP) is extensively utilized as an additive in plastic products, and both DBP and MPs are widespread in the environment. However, the combined toxicity of these substances remains uncertain. In this study, zebrafish embryos were employed to assess the toxic effects of polyethylene terephthalate (PET, MPs) and DBP, with a focus on the DBP toxicities influenced by PET. The embryonic chorion was partially covered by PET particles, and PET led to a delayed hatching of zebrafish embryos without inducing death or teratogenesis. On the other hand, exposure to DBP considerably inhibited the hatching of embryos, leading to severe lethal and teratogenic effects. The most common phenotypes induced by DBP exposure were delayed yolk sac absorption and pericardial edema. The mortality increased in co-treatment with 100 particles/mL PET and 2 mg/L DBP at 24 hpf and 48 hpf. The malformation phenotype, bent notochord, and delayed yolk sac absorption became more severe in 1 mg/L DBP exposition with the co-exposure of 100 particles/mL PET at 72 hpf. PET might act as a carrier that enhances the bioavailability of ambient DBP.
Analysis of Resonant Periodic Orbits in the Framework of the Perturbed Restricted Three Bodies Problem
Authors: Patel Bhavika M. , Pathak Niraj M. , Abouelmagd Elbaz I.
Published: May 2023

In this work, the perturbed equations of motion of the infinitesimal body are constructed in the framework of the circular restricted three-body problem when the main two bodies are oblate and radiating. Under the perturbations effects of the oblateness and the radiation pressure the positions of collinear Lagrange points are evaluated, the interior and exterior first-order resonant periodic orbits are also studied. In addition, the initial positions of the periodic orbits and the size of loops have been estimated under these effects. Thus, the characteristics of periodic orbits have been studied under the combine effects of two, three and four perturbations for all the possible combinations of the perturbed parameters. The different order of resonant periodic orbits have been also analysed under the effects of Jacobi constant, mass factor, order of resonance and number of loops.
Association of Polymorphisms of IL-6 Pathway Genes (IL6, IL6R and IL6ST) with COVID-19 Severity in an Amazonian Population
Authors: Rodrigues Fabíola Brasil Barbosa , da Silva Rosilene , Santos Erika Ferreira dos , de Brito Mioni Thieli Figueiredo Magalhães , da Silva Andréa Luciana Soares , de Meira Leite Mauro , Póvoa da Costa Flávia , de Nazaré do Socorro de Almeida Viana Maria , de Sarges Kevin Matheus Lima , Cantanhede Marcos Henrique Damasceno , Veríssimo Adriana de Oliveira Lameira , Carvalho Mayara da Silva , Henriques Daniele Freitas , Silva Carla Pinheiro da , Costa Igor Brasil , Nunes Juliana Abreu Lima , Costa Iran Barros , Viana Giselle Maria Rachid , Queiroz Maria Alice Freitas , Lima Sandra Souza , Lopes Jeferson da Costa , Torres Maria Karoliny da Silva , Vallinoto Izaura Maria Vieira Cayres , Bichara Carlos David Araújo , Vallinoto Antonio Carlos Rosário , Santos Eduardo José Melo dos
Published: May 2023

Interleukin-6 has been recognized as a major role player in COVID-19 severity, being an important regulator of the cytokine storm. Hence, the evaluation of the influence of polymorphisms in key genes of the IL-6 pathway, namely IL6, IL6R, and IL6ST, may provide valuable prognostic/predictive markers for COVID-19. The present cross-sectional study genotyped three SNPs (rs1800795, rs2228145, and rs7730934) at IL6. IL6R and IL6ST genes, respectively, in 227 COVID-19 patients (132 hospitalized and 95 non-hospitalized). Genotype frequencies were compared between these groups. As a control group, published data on gene and genotype frequencies were gathered from published studies before the pandemic started. Our major results point to an association of the IL6 C allele with COVID-19 severity. Moreover, IL-6 plasmatic levels were higher among IL6 CC genotype carriers. Additionally, the frequency of symptoms was higher at IL6 CC and IL6R CC genotypes. In conclusion, the data suggest an important role of IL6 C allele and IL6R CC genotype on COVID-19 severity, in agreement with indirect evidence from the literature about the association of these genotypes with mortality rates, pneumonia, and heightening of protein plasmatic levels pro-inflammatory driven effects.
Poly(I:C) Induces Distinct Liver Cell Type-Specific Responses in Hepatitis B Virus-Transgenic Mice In Vitro, but Fails to Induce These Signals In Vivo
Authors: Schefczyk Stefan , Luo Xufeng , Liang Yaojie , Trippler Martin , Lu Mengji , Wedemeyer Heiner , Schmidt Hartmut H. , Broering Ruth
Published: May 2023

Immunopathology in hepatitis B virus (HBV) infection is driven by innate and adaptive immunity. Whether the hepatitis B surface antigen (HBsAg) affects hepatic antiviral signalling was investigated in HBV-transgenic mouse models that either accumulate (Alb/HBs, Tg[Alb1HBV]Bri44), lack (Tg1.4HBV-s-mut3) or secrete (Tg1.4HBV-s-rec (F1, Tg1.4HBV-s-mut × Alb/HBs) the HBsAg. Herein, the responsiveness of TLR3 and RIG-I in primary parenchymal and non-parenchymal liver cells was determined in vitro and in vivo. Cell type-specific and mouse strain-dependent interferon, cytokine and chemokine expression were observed by LEGENDplex™ and validated by quantitative PCR. In vitro, the hepatocytes, liver sinusoidal endothelial cells and Kupffer cells of Tg1.4HBV-s-rec mice showed poly(I:C) susceptibilities similar to the wild-type controls, while in the remaining leucocyte fraction the interferon, cytokine and chemokine induction was reduced. On the contrary, poly(I:C)-injected 1.4TgHBV-s-rec mice showed suppressed interferon, cytokine and chemokine levels in hepatocytes but increased levels in the leucocyte fraction. Thus, we concluded that liver cells of Tg1.4HBV-s-rec mice, which produce HBV particles and release the HBsAg, responded to exogenous TLR3/RIG-I stimuli in vitro but exhibited a tolerogenic environment in vivo.
Clinical Outcomes of Descemet’s Membrane Endothelial Keratoplasty without Routine Prophylactic Peripheral Iridotomy
Authors: Mukhija Ritika , Quiney Gabriella , Nanavaty Mayank A.
Published: May 2023

Objectives: To analyze the outcomes and complications of Descemet‘s membrane endothelial keratoplasty (DMEK) performed without prophylactic peripheral iridotomy (PI). Methods: Design: Retrospective study. Setting: Institutional, tertiary care eye hospital. Study Population: All patients who underwent DMEK or DMEK combined with phacoemulsification (DMEK triple) for Fuchs endothelial dystrophy, using a standardized protocol between August 2016 and July 2021, were included. Previous glaucoma surgery, laser PI, aphakia, or complicated pseudophakia were excluded. Main outcome measures: Primary outcomes: Incidence of pupillary block (PB). Secondary outcomes: Graft detachment (GD), rebubbling rates, uncorrected (UCDVA) and best corrected logMAR distance visual acuity (BCDVA), and endothelial cell loss (ECL) at six months. Data were analyzed using the chi-square test and stepwise backward regression analysis. Results: 104 eyes of 72 patients were included. Four eyes (3.8%) developed PB; in two of these cases, standard protocol was not followed. Overall minor GD occurred in 43.2% (n = 45); significant GD was present only in 7 eyes (6.6%). Overall slit lamp rebubbling rate was 30% (n = 35), though only four patients were rebubbled in theatre (3.8%). PB, GD, and rebubbling rates did not vary with the surgeon, surgery, or tamponade (air or SF6 gas). UCDVA, BCDVA, and ECL at 6 months were 0.29 ± 0.31, 0.20 ± 0.28, and 40.46 ± 20.36%, respectively. Conclusions: Compared to previously reported outcomes of DMEK with PI, our results of PI less DMEK using a standardized protocol have a similar incidence of pupillary block, graft detachment, and rebubbling, with comparable visual acuity and endothelial cell loss.
Using Principal Component Analysis (PCA) Combined with Multivariate Change-Point Analysis to Identify Brine Layers Based on the Geochemistry of the Core Sediment
Authors: Su Qiao , Yu Hongjun , Xu Xingyong , Chen Bo , Yang Lin , Fu Tengfei , Liu Wenquan , Chen Guangquan
Published: May 2023

The underground brine in Southern Laizhou Bay is characterized by its large scale and high concentration, which can affect the distribution and migration of geochemical elements in sediments. Most studies on the brine are based on hydrochemical analysis, with little consideration being given from a geochemical perspective. Principal component analysis (PCA) is a powerful tool for discovering relationships among many elements and grouping samples in large geochemical datasets. However, even after reducing the dimensions through PCA, researchers still need to make judgments about the meaning represented by each principal component. Change-point analysis can effectively identify the points at which the statistical properties change in a dataset. PCA and change-point analysis have their respective advantages in the study of large sets of geochemical data. Based on the geochemical data of the LZ908 core, by combining these two methods, this study identified four elements (U, MgO, Br, and Na2O) related to the action of seawater through PCA; then, multivariate change point analysis was conducted on these elements to detect the depths of different brine layers. The results of the analysis are basically consistent with those of other studies based on the water content, salinity, and other data, thus proving the effectiveness of this method. The combination of these two methods may also lead to novel approaches for related research.