Structural Approach Research Articles

Value engineering implementation in construction projects in Morocco: Awareness, benefits and challenges

Value engineering is a systematic and structured approach that aims to optimize the value of a project by analyzing its components and functions. This article intends to explore the current level of awareness of value engineering, the benefits that can be derived, and the major challenges of successful implementation in construction projects in Morocco. The study was conducted based on a quantitative approach using a structured survey among construction professionals in Morocco. Interviews were carried out with academics, representatives of project owners, technical design offices, and work execution companies, and responses to the questionnaire were collected from various stakeholders in the field of construction in Morocco. The results show that value engineering is still in its infancy in the Moroccan construction sector since 65 percent of respondents are not familiar with the concept of value engineering and only 8% of respondents have implemented value engineering with its recognized standards. The findings have also confirmed the benefits of implementing value engineering in construction projects in Morocco, especially significant potential savings, both initial and Life-Cycle Costs, the reduction of completion times, and early uncovering of potential design deficiencies or alternative approaches. The major challenges emphasized in this study are the understanding and support of top management, the resistance of designers, and the adaptation of the contracts of the stakeholders. This is the first scientific article addressing the value engineering process and its adoption in the construction sector in Morocco. Thus, it could be considered as a first step towards comprehension and vulgarization of value engineering concepts and techniques among construction professionals in Morocco. This study presents for the first time the level of awareness of value engineering in the construction sector in Morocco, demystifies the process as a whole, emphasizes the potential benefits derived from it, and clarifies the major challenges to a successful implementation.

Retraction notice: Investigating sustainable development for the COVID-19 vaccine supply chain: a structural equation modelling approach

Retraction notice: Investigating sustainable development for the COVID-19 vaccine supply chain: a structural equation modelling approach

Architecture of the Sap S-layer of Bacillus anthracis revealed by integrative structural biology

Bacillus anthracis is a spore-forming gram-positive bacterium responsible for anthrax, an infectious disease with a high mortality rate and a target of concern due to bioterrorism and long-term site contamination. The entire surface of vegetative cells in exponential or stationary growth phase is covered in proteinaceous arrays called S-layers, composed of Sap or EA1 protein, respectively. The Sap S-layer represents an important virulence factor and cell envelope support structure whose paracrystalline nature is essential for its function. However, the spatial organization of Sap in its lattice state remains elusive. Here, we employed cryoelectron tomography and subtomogram averaging to obtain a map of the Sap S-layer from tubular polymers that revealed a conformational switch between the postassembly protomers and the previously available X-ray structure of the condensed monomers. To build and validate an atomic model of the lattice within this map, we used a combination of molecular dynamics simulations, X-ray crystallography, cross-linking mass spectrometry, and biophysics in an integrative structural biology approach. The Sap lattice model produced recapitulates a close-to-physiological arrangement, reveals high-resolution details of lattice contacts, and sheds light on the mechanisms underlying the stability of the Sap layer.

Nuclear lipids in chromatin regulation: Biological roles, experimental approaches and existing challenges.

Lipids are crucial for various cellular functions. Besides the storage of energy equivalents, these include forming membrane bilayers and serving as signaling molecules. While significant progress has been made in the comprehension of the molecular and cellular biology of lipids, their functions in the cell nucleus remain poorly understood. The main role of the eukaryotic cell nucleus is to provide an environment for the storage and regulation of chromatin which is a complex of DNA, histones, and associated proteins. Recent studies suggest that nuclear lipids play a role in chromatin regulation and epigenetics. Here, we discuss various experimental methods in lipid-chromatin research, including biophysical, structural, and cell biology approaches, pointing out their strengths and weaknesses. We take the view that nuclear lipids have a far more widespread impact on chromatin than is currently acknowledged. This gap in comprehension is mostly due to existing experimental challenges in the study of lipid-chromatin biology. Several new, interdisciplinary approaches are discussed that could aid in elucidating the roles of nuclear lipids in chromatin regulation and gene expression.

A versatile real-time vision-led runway localisation system for enhanced autonomy

This paper proposes a solution to the challenging task of autonomously landing Unmanned Aerial Vehicles (UAVs). An onboard computer vision module integrates the vision system with the ground control communication and video server connection. The vision platform performs feature extraction using the Speeded Up Robust Features (SURF), followed by fast Structured Forests edge detection and then smoothing with a Kalman filter for accurate runway sidelines prediction. A thorough evaluation is performed over real-world and simulation environments with respect to accuracy and processing time, in comparison with state-of-the-art edge detection approaches. The vision system is validated over videos with clear and difficult weather conditions, including with fog, varying lighting conditions and crosswind landing. The experiments are performed using data from the X-Plane 11 flight simulator and real flight data from the Uncrewed Low-cost TRAnsport (ULTRA) self-flying cargo UAV. The vision-led system can localise the runway sidelines with a Structured Forests approach with an accuracy approximately 84.4%, outperforming the state-of-the-art approaches and delivering real-time performance. The main contribution of this work consists of the developed vision-led system for runway detection to aid autonomous landing of UAVs using electro-optical cameras. Although implemented with the ULTRA UAV, the vision-led system is applicable to any other UAV.

Analyzing the Effect of Factors on Individuals’ Subjective Well-Being with Quantile Bayesian Structural Equation Modeling Approach

This study investigates factors influencing individuals’ levels of subjective well-being by examining fundamental variables, called life domains, such as satisfaction with health, education, marriage, housing district, work life, social life, relationships, and public services. The aim is to understand how these domains affect various quantile values of subjective well-being. To achieve this, the Life Satisfaction Survey dataset for 2020, obtained from the Turkish Statistical Institute, was utilized, and Bayesian Quantile Structural Equation Modeling and Bayesian Structural Equation Modeling methods were applied. The empirical study indicates that all life domains were found to have a positive impact on subjective well-being, except for housing-district satisfaction and education satisfaction. In particular, for individuals with low subjective well-being, satisfaction with work life, relationships, and public services has a stronger effect on subjective well-being compared to those in higher quantiles. Conversely, marriage satisfaction has a stronger effect on subjective well-being among individuals in the higher quantiles. This study’s unique contribution is that examining subjective well-being according to quantile values provides detailed information on how the factors influencing individuals’ subjective well-being vary across different levels.

Shear Stress Solutions for Curved Beams: A Structural Analysis Approach

The shear stress on isotropic curved beams with compact sections and variable thickness is investigated. Two new solutions, based on Cook’s proposal and the mechanics of materials approach, were developed and validated using computational finite element models (FEM) for four typical cross-sections (rectangular, circular, elliptical, and triangular) used in civil and mechanical structures, constituting a novel approach to predicting shear stresses in curved beams. They predict better results than other reported equations, are simpler and easier for engineers to use quickly, and join the group of equations found using the theory of elasticity, thereby expanding the field of knowledge. The results reveal that both equations are suitable to predict the shear stress on a curved beam with outer/inner radii ratios in the interval 1<b/a ≤ 5 aspect ratios. There is a maximum relative difference between the present solutions and finite element models of 8% within 1<b/a ≤ 2, and a maximum of 16% in 2<b/a ≤ 5. Additionally, the neutral axis of the curved beam can be located with the proposed solution and its position matches with that predicted by FEM. The displacement at the top face of the end of the curved beam induces a difference in the shear stress results of 8.0%, 7.0%, 6.5%, and 2.9%, for the circular, rectangular, elliptical, and triangular cross-sections, respectively, when a 3D FEM solution is considered. For small b/a ratios (near 1), the present solutions can be reduced to Collignon’s formula.

Exquisite selectivity of griselimycin extends to beta subunit of DNA polymerases from Gram-negative bacterial pathogens

Griselimycin, a cyclic depsidecapeptide produced by Streptomyces griseus, is a promising lead inhibitor of the sliding clamp component of bacterial DNA polymerases (β-subunit of Escherichia coli DNA pol III). It was previously shown to inhibit the Mycobacterium tuberculosis β-clamp with remarkably high affinity and selectivity – the peptide lacks any interaction with the human sliding clamp. Here, we used a structural genomics approach to address the prospect of broader-spectrum inhibition, in particular of β-clamps from Gram-negative bacterial targets. Fifteen crystal structures of β-clamp orthologs were solved, most from Gram-negative bacteria, including eight cocrystal structures with griselimycin. The ensemble of structures samples widely diverse β-clamp architectures and reveals unique protein-ligand interactions with varying degrees of complementarity. Although griselimycin clearly co-evolved with Gram-positive β-clamps, binding affinity measurements demonstrate that the high selectivity observed previously extends to the Gram-negative orthologs, with KD values ranging from 7 to 496 nM for the wild-type orthologs considered. The collective results should aid future structure-guided development of peptide antibiotics against β-clamp proteins of a wide variety of bacterial targets.

Cultural intelligence and cooperation in the construction industry: the mediating role of trust

Purpose This study aims to investigate the mediating role of trust in the relationship between cultural intelligence (CQ) and cooperation among construction professionals. Furthermore, this study assesses perceived differences in CQ, trust and cooperation between individuals with and without experience working with foreigners in the construction industry. Design/methodology/approach Data were gathered from a cross-sectional survey of 408 engineers in Myanmar’s construction industry. A confirmatory factor analysis validated structural equation modeling approach was used to address research hypotheses, and an independent samples t-test was performed to identify the perceived differences between two categories of respondents. Findings The structural equation modeling results identified CQ as a positive direct predictor of cooperation, affect-based trust and cognition-based trust. Both affect-based trust and cognition-based trust directly and positively influenced cooperation. The relationship between CQ and cooperation was partially mediated by affect-based trust and cognition-based trust. The findings of the independent samples t-test revealed that construction employees with prior experience working with foreigners tend to exhibit a higher level of CQ, trust and cooperation than their counterparts. Originality/value The present study added the mediating role of trust in CQ and cooperation linkage, an area that has received limited attention in the literature.

Factors predicting the mathematics anxiety of adolescents: a structural equation modeling approach

IntroductionMathematics anxiety (MA) is a distinct negative emotional state or trait that individuals experience when confronted with mathematical problems in everyday life and academic contexts. This study aims to identify the key predictors of MA among secondary-level students in Bangladesh.MethodsUtilizing a quantitative cross-sectional research design, data were collected from 486 students across 89 institutions. Later, the data were analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM).ResultsThe findings revealed that math related negative past experiences (β = 0.241, t = 4.914, p < 0.001) and a perceived lack of teacher support (β = 0.234, t = 5.440, p < 0.001) significantly contribute to students’ low self-efficacy in mathematics. This low self-efficacy is further influenced by negative attitudes and test anxiety, ultimately leading to increased MA (β = 0.694, t = 22.695, p < 0.001). Additionally, cognitive challenges, particularly working memory difficulties, directly affect MA (β = 0.110, t = 2.659, p = 0.008). The study also found that negative attitudes (β = 0.347, t = 9.063, p < 0.001) and test anxiety (β = 0.251, t = 5.913, p < 0.001) independently exacerbate MA. Moreover, a lack of motivation in learning mathematics is directly influenced by this elevated level of MA (β = 0.384, t = 9.939, p < 0.001).DiscussionTaken together, the study proposes several key recommendations and policy implications to inform the development of synchronized policies by educational authorities aimed at combatting, reducing MA among secondary-level students in Bangladesh and similar contexts.

Assessing the Impact of E-Commerce of a Footwear Vendor in Malaysia Through a Structural Equation Modeling Approach

Assessing the Impact of E-Commerce of a Footwear Vendor in Malaysia Through a Structural Equation Modeling Approach

Safety net of last resort: the evolution, determinants and adequacy of Dutch minimum income support

Dutch minimum income support provides a generous social safety net compared to most other European Union (EU) member states but has not been able to structurally reduce poverty. This inadequacy did not come about overnight but is the result of six decades of policy decisions. In this article, we aim to explain the current income shortfalls of people on minimum income support by studying the historical evolution and determinants of the Dutch minimum income scheme. We demonstrate that it has on average maintained a constant level of purchasing power over the period 1980–2023. This fits well with the notion that poverty is of an absolute nature, and that a social minimum should guarantee a stable level of purchasing power. It fits less well with relative or contextual approaches to poverty, and the view that a social minimum should adapt to changing norms when a society grows richer. To uncover the reasons for the growing gap between general prosperity and the minimum income benefit, we decompose it into smaller gaps by illustrating the evolution of prosperity, labour productivity, gross wages, collectively agreed wages, the minimum wage and the minimum income benefit. We show that each of these gaps matters and argue that this provides valuable insights into the structural, institutional and political forces that have shaped Dutch minimum income support since its introduction in 1965. Based on these results, we argue against the current ad hoc measures of the government and in favour of a more structural approach to supporting low-income households.

Structures of Oligomeric States of Tau Protein, Amyloid-β, α-Synuclein and Prion Protein Implicated in Alzheimer’s Disease, Parkinson’s Disease and Prionopathies

In this review, we focus on the biophysical and structural aspects of the oligomeric states of physiologically intrinsically disordered proteins and peptides tau, amyloid-β and α-synuclein and partly disordered prion protein and their isolations from animal models and human brains. These protein states may be the most toxic agents in the pathogenesis of Alzheimer’s and Parkinson’s disease. It was shown that oligomers are important players in the aggregation cascade of these proteins. The structural information about these structural states has been provided by methods such as solution and solid-state NMR, cryo-EM, crosslinking mass spectrometry, AFM, TEM, etc., as well as from hybrid structural biology approaches combining experiments with computational modelling and simulations. The reliable structural models of these protein states may provide valuable information for future drug design and therapies.

On the efficiency of trading intangible fixed assets in Major League Baseball

Abstract This paper proposes novel approaches to measuring team productivity and evaluating trading efficiency in Major League Baseball (MLB) from 1995 to 2021 through an application of portfolio theory. The performance of individual players is measured using a structural approach relating player outcomes to team runs developed by Lindsey (1963. An investigation of strategies in baseball. Oper. Res. 11: 477–501). Using a portfolio theory framework, we treat MLB teams as a portfolio of players (assets), each of which can be defined by an expected contribution of runs per game and the variance of this measure. It is found that both the expected value and variance have a positive impact on team runs scored. Given our definition of teams characterized by their expected values and variances, we evaluate trading efficiency between teams given their pre-trade expected values and variances and the acquired player’s pre-trade expected value and variance. We find that trade efficiency has improved over our timeframe, consistent with the growth in data-driven decision making used in MLB front offices.

Tolerance Attitude Analysis of the Social Piety Value in the Novel Lingkar Tanah Lingkar Air Based on Prophetic Ethics

This study analyzes tolerance attitude as a manifestation of social piety values within the framework of prophetic ethics in the novel Lingkar Tanah Lingkar Air by Ahmad Tohari. This study aims to understand how the novel depicts tolerance in the context of diversity in Indonesia. Using Goldmann's genetic structuralism approach and Jurij Lotman's semiotics, qualitative research methods were used, involving hermeneutic analysis and interviews with the author. The results showed a binary opposition between the character Kang Suyud, who represents a rigid interpretation of Islam, and Kyai Ngumar, who prioritizes tolerance. The novel illustrates how differences in religious understanding do not have to lead to conflict, emphasizing the importance of social piety manifested through tolerance and empathy. Kyai Ngumar's tolerant attitude contrasts with Kang Suyud's intolerance, showing the importance of moderation and understanding diversity to maintain social harmony in Indonesia, aligning with prophetic ethical values. This study concludes that tolerance is the key to building an inclusive society in Indonesia, which is rich in cultural and religious diversity.

Fostering Sustainable Development Through Women’s Entrepreneurship: Psychosocial Factors and Attitudinal Mediation in Colombian Higher Education

University female entrepreneurship has seen significant growth in Colombia in recent years. This study aimed to examine the psychosocial factors that determine the entrepreneurial intent of Colombian university women, specifically analyzing how entrepreneurial attitude mediates the relationship between these factors and the intent to engage in entrepreneurship using a structural equation modeling approach (SEM). A total of 409 university students from various higher education institutions in Colombia participated by completing an online survey. The results demonstrated that extrinsic motivation (β = 0.178 moderate intensity), family environment (β = 0.127 moderate intensity), innovation (β = 0.462 very intense), and intrinsic motivation (β = 0.117 low intensity) positively influence entrepreneurial attitude, which in turn has a significant positive effect on the intent to engage in entrepreneurship (β = 0.709 very intense). Furthermore, innovation, extrinsic motivation, family environment, and intrinsic motivation indirectly influence entrepreneurial intent through their impact on attitude. In conclusion, this study provides a deeper understanding of the psychosocial mechanisms that drive female entrepreneurship in the Colombian university context and lays the groundwork for the design of educational programs and public policies that enhance the talent and entrepreneurial aspirations of women in higher education.

Performance Analysis of a Water-Injected Twin-Screw Compressor in a High-Temperature R718 Heat Pump

Abstract High-temperature heat pumps with twin-screw compressors and water (R718) as the working fluid show promising potential for providing industrial heat and process steam at temperature levels of up to 200 °C. This paper presents a simulation approach for a two-layered simulation structure of a water-based high-temperature heat pump system including a twin-screw compressor with water-injection. The heat pump process with two-phase steam compression is investigated with respect to various aspects. In addition to controlling the compressor outlet temperature, the evaporation of the injected liquid leads to an increase in the displaced mass flow rate on the sink side of the heat pump. This effect is analyzed in detail for various system operating points using a thermodynamic simulation framework for the R718-based heat pump cycle and a comprehensive compressor model. The main target of the presented paper is the analysis of system performance and the detailed investigation of the interdependencies. Performance of the twin-screw compressor is determined by means of two-phase chamber model simulations. In the chamber model method thermodynamic properties of both injected liquid and steam are calculated based on the conservation equations of mass and energy for the compression process. Adequate sub-models for internal leakage and heat and mass transfer between vapor and liquid phase are applied. Integral results of the compressor simulations are embedded in the heat pump system simulation using a characteristic map. In conclusion, this paper contributes to the understanding of advanced compression technologies in the field of high-temperature heat pumps, offering a detailed examination of a water-injected steam compressor’s applicability and efficiency in a practical system setting.

A polyolefin separator reinforced inorganic/organic composite electrolyte for quasi-solid-state Lithium-sulfur batteries with high cycle stability and long lifespan

Lithium-sulfur (Li-S) batteries are considered a promising next-generation energy storage system due to the high energy density and the low cost. However, the severe shuttle effect of polysulfide and the security issue caused by organic liquid electrolyte and lithium metal anode have hindered their commercial application. Herein we achieved a polyolefin commercial separator reinforced inorganic/organic composite electrolyte (denoted as Com-LATP) via coating the polypropylene (PP) separator with the composite of polymethyl methacrylate/poly(vinylidene fluoride) (PMMA/PVDF) modified with Li1.3Al0.3Ti1.7(PO4)3 (LATP). The Com-LATP electrolyte (thickness: ∼30 um) exhibits remarkable tensile strength of 103 MPa, an ionic conductivity of 0.47·mS cm-1 with the Li+ transfer number of 0.45, which is beneficial for the uniform Li+ flux and the stable striping and plating of Li metal. The Li symmetrical batteries equipped with this Com-LATP exhibited stable cycling for over 350 h. Meanwhile, the Com-LATP electrolyte with the special dense structure can hinder the polysulfide diffusion. The developed quasi-solid-state lithium-sulfur batteries have demonstrated impressive cycling stability with an initial specific capacity of 1184.8 mA h g-1 at a discharge rate of 0.2 C, maintaining performance over 200 cycles. Additionally, they exhibited outstanding rate capability, retaining a reversible capacity of 710.4 mA h g-1 even at a higher discharge rate of 2 C. This research introduces an innovative structural design approach for high-performance quasi-solid-state Li-S batteries, which holds significant promise for advancing the commercialization of lithium-sulfur battery technology.

A Binary Structured Sparsity Approach for Multi-Anchor Direct Localization

A Binary Structured Sparsity Approach for Multi-Anchor Direct Localization

Predicting the intention to install solar photovoltaic panels in emerging market: The role of consumer innovativeness, knowledge, and support for government incentives

Promoting the installation of solar photovoltaic panels at the residential level in Vietnam may effectively mitigate the electricity overload on the national grid and support the country’s sustainable objectives. However, the installation rates of this system in urban areas in Vietnam remains low despite the favorable atmosphere and the provision of several incentives. Based on the Diffusion of Innovation and Theory of Planned Behavior, this study explores the role of consumer innovativeness, knowledge, and support for government incentives on the diffusion and social acceptance of solar photovoltaic panels. A questionnaire survey was conducted to collect data for analysis. With a sample of 339 citizens in Vietnam, the partial least squares structural equation modeling approach was employed to evaluate the results. The findings revealed that consumer innovativeness was linked to social norms and knowledge. Furthermore, it was discovered that the knowledge of consumers can significantly enhance the support for government incentives and the intention to install solar photovoltaic panels. Additionally, social norms significantly influenced attitudes, ultimately resulting in an increase in the intention to install. The findings of this study could aid the nation's policymakers and institutions in formulating strategies to grow the solar energy sector, therefore facilitating the achievement of sustainable energy goals.