Earlier Studies Research Articles

Ensemble Learning Models for Prediction of Punching Shear Strength in RC Slab-Column Connections

In reinforced concrete (RC) structures, accurate prediction of the punching shear strength (PSS) of slab-column connections is imperative for ensuring safety. The existing equations in the literature show variability in defining parameters influencing PSS. They neglect potential variable interactions and rely on a limited dataset. This study aims to develop an accurate and reliable model to predict the PSS of slab-column connections. An extensive dataset, including 616 experimental results, was collected from earlier studies. Six robust ensemble machine learning techniques—random forest, gradient boosting, extreme gradient boosting, adaptive boosting, gradient boosting with categorical feature support, and light gradient boosting machines—are employed to predict the PSS. The findings indicate that gradient boosting stands out as the most accurate method compared to other prediction models and existing equations in the literature, achieving a coefficient of determination of 0.986. Moreover, this study utilizes techniques to explain machine learning predictions. A feature importance analysis is conducted, wherein it is observed that the reinforcement ratio and compressive strength of concrete demonstrate the highest influence on the PSS output. SHapley Additive exPlanation is conducted to represent the influence of variables on PSS. A graphical user interface for PSS prediction was developed for users’ convenience. Doi: 10.28991/CEJ-SP2024-010-01 Full Text: PDF

Gender Differences in Cognitive Abilities in Human Adults

Modern world of globalization and unification is of particular interest considering the rapid changes in men's and women's dispositions and engagement in societal institutions. According to these contemporary developments of the psychosocial context, cognitive differences between females and males may also be changing. The aim of this study was to update findings from the last two decades regarding gender differences in cognitive abilities. Major updated results confirm earlier studies and demonstrate relevant gender differences in spatial abilities, verbal skills, emotional processing and executive functions. Like earlier studies, the new data also show small to trivial gender differences in mathematics performance, yet gender effects on complex problem solving are found to be smaller than in 1990 meta-analyses. The updated data confirm that gender differences in cognitive abilities do exist despite the increasing unification of men's and women's involvement in psychosocial contexts. Moreover, new scientific approaches demonstrate that these gender-specific cognitive differences are grounded on hormonal, neuroanatomical and neurofunctional substrates emphasizing their biological origin. Although the psychosocial interaction is of relevance, the primary biological basis of gender differences should be very strongly and carefully considered.

A1-Mart (The e-Commerce Web Application)

Online Shopping play a great importance in the modern business environment. A1-Mart (The e-Commerce Web Application) has opened the door of opportunity and advantage to the firms. This paper analyzed the different issue of online shopping. The research aims to provide theoretical contribution in understanding the present status of online shopping. The Study Discuss the consumers’ online shopping behaviors. Papers also identify the problems face by the consumers when they want to accept internet shopping. Present paper is an expressive study based on the detailed review of earlier pertinent studies related to the various concepts of online shopping to discover the concept of online shopping. Solitude and safety risk emerge regularly as a reason for being cautious about internet shopping. Shopping convenience, information seeking, social contact, and diversity affects the consumer attitude towards online shopping. The impossibility of product testing, problems with complaints, product return and missus of personal data are the main doubts regarding on-line shopping.

Rosacea is strongly associated with melanoma in Caucasians

Rosacea is often considered a cosmetic problem but is known to be associated with a variety of comorbidities. To identify such risks, we generated two age- and sex-matched real-world cohorts of 122,444 patients each with and without rosacea. In contrast to earlier studies, we found significant associations with malignant melanoma (OR 6.02, 95% CI 5.76–6.32). This association does not exist for an Asian sub-cohort, which could explain previous inconclusive or conflicting reports. Several strongly associated comorbidities like visual disturbances (ICD-10: H53–H54; OR 4.80, 4.68–4.92), metabolic disorders (E73–E79; OR 3.17, 3.11–3.22), joint problems (M25; OR 4.16, 4.08–4.25) and type 2 diabetes (E11; OR 1.62, 1.58–1.65) should be watched as a risk for rosacea patients. Rosacea is associated with some comorbidities and ethnicity may be a risk factor in melanoma development. The retrospective nature of this study and the sole use of ICD-10 code based filtering calls for future validation of our findings. Additionally, confounding factors such as skin type and previous UV exposure should be included in future studies.

Plasticity in resource allocation of the invasive Phytolacca americana: Balancing growth, reproduction, and defense along urban–rural gradients

In response to varying environments along urban and rural gradients, invasive plants may strategically allocate resources to enhance their invasiveness. However, how invasive plants balance their resources for growth, reproduction, and defense as responses to biotic and abiotic factors across these gradients remain unclear. We conducted field surveys on the growth, reproduction, and herbivory of the invasive species Phytolacca americana across diverse urban and rural habitats. Leaf samples were collected to analyze the nutritional content, primary and secondary metabolites. We found that plant growth rates, specific leaf area, leaf nitrogen content, and concentrations of flavonoids and saponins were higher in urban habitats, while reproduction, herbivory, and carbon-to‑nitrogen ratios were lower than those in rural habitats. We also found a trade-off between growth rate and herbivory, as well as trade-offs among defense traits associated with herbivory (e.g., leaf mass per area, the inverse of leaf nitrogen content, and carbon‑nitrogen ratio) and the production of metabolites associated with abiotic stress tolerance (e.g., soluble sugars, flavonoids, and saponins). As earlier studies showed low levels of genetic diversity within and between populations, our findings suggest that the urban–rural gradient patterns of resource allocation are primarily phenotypic plasticity in response to herbivory in rural areas and abiotic factors in urban areas. Our study sheds light on the mechanisms by which urbanization affects plant invasions and offers insights for the implementation of their management strategies.

Revisiting circulation and water masses over the East Antarctic margin (80–150°E)

Full-depth hydrographic sections of the BROKE experiment in 1996 (across the Antarctic margin from 80 to 150°E; Bindoff et al., 2000) were revisited for the first time during the 2018/2019 austral summer. We describe the subsurface physical oceanography in 2019 and the hydrographic changes between 1996 and 2019 not documented in earlier studies. The survey captured decadal changes in ocean structure from the southern flank of the Antarctic Circumpolar Current (ACC) to the continental shelves. In five cross-slope meridional sections, where 1996 and 2019 measurements are comparable (112, 120, 128, 140, and 150°E), the poleward shift of the southern boundary of the ACC (50–120 km) prevailed near the continental rise. The simultaneous displacement of barotropic ACC fronts and poleward migration of deep water contributed to full-depth warming (0.1–1.6 °C) and potentially to a reduction in the bottom water volume. Freshening was widely observed from the deep to bottom layers (∼0.02 g/kg), with the signal extending from the upper continental slope. Bottom-intensified freshening was accompanied by an oxygenation of 10–20 μmol/kg, indicating that freshening-driven oxygenation of bottom layers counteracted the deoxygenation effect of the poleward barotropic frontal shift. Westward transport of the Antarctic Slope Current decreased by more than 10 Sv from 1996 to 2019 in the five cross-slope sections; its frontal features and current axis shifted offshore by more than 20 km in 112–140°E. Additionally, subsurface warming along modified Circumpolar Deep Water by up to 0.4 °C was commonly detected across the upper continental slope. For the 2019 hydrography, shelf water sufficiently dense to form bottom water (>28.35 kg/m3) was found to the east of Mertz Polynya (142–148°E), implying a pathway for dense shelf water export from the eastern margin of Mertz Polynya. Our findings underscore the importance of sustained efforts for in-situ observations that widely cover the East Antarctic margin.

Subarachnoid haemorrhage and intracranial aneurysms in Greenland in the period 2018–2021: incidence, outcome and familial disposition

ABSTRACT Subarachnoid haemorrhages (SAH) caused by rupture of intracranial aneurysms (IA) are a severe condition. Earlier studies found a higher incidence of SAH in Greenlandic patients compared to Danish patients, with familial aggregation also higher in Greenland. However, updated data is lacking. To investigate the contemporary incidence, outcome, and familial disposition of SAH/IA in Greenlandic patients in 2018–2021. Greenlandic patients diagnosed with ruptured or unruptured IA (UIA) during 2018–2021 were included. Data was obtained from patient files, x-ray department, and discharge registry. Incidence rates were estimated as cases/100,000/year. Direct age-standardised incidence rates were calculated using WHO 2000–2025 as standards. Of 30 SAH patients, 20 (66.7%) were females, 10 (33.3%) males. Of 36 UIA patients, 27 (75.0%) were females, 9 (25.0%) males. For SAH, crude incidence was 13.4/100,000/year, age-standardised incidence was 10.8/100,000/year. Familial history was observed in 30.0% of SAH patients. 5 patients (16.7%) died before treatment, 28-day case-fatality rate (CFR) for all patients was 23.3%. Overall and age-standardised incidence rates were similar to previous studies but higher among females and compared to neighbouring countries. A high occurrence of familial history was reported. SAH remains a serious condition in Greenland, as evidenced by five fatalities before treatment was administered.

Evaluating the efficacy of pre-ablation algorithms in WPW syndrome localization: a retrospective study

Abstract Background and Objective Wolf-Parkinson-White (WPW) syndrome is a congenital condition that can be diagnosed at any age and may lead to dysrhythmias, most notably atrioventricular reentrant tachycardia (AVRT). Ablation of the accessory pathway responsible for the disorder has become a standard treatment approach. The success of ablation therapy is closely linked to accurately localizing the accessory pathway. Consequently, algorithms have been developed to predict the location of the accessory pathway using pre-ablation electrocardiography (ECG) parameters. This study aims to evaluate the predictive values of previously published algorithms. Method This study included 122 patients diagnosed with WPW syndrome who underwent successful ablation of a manifest accessory pathway at our university's cardiac electrophysiology laboratory between 2019 and 2023. We retrospectively examined these patients' baseline characteristics and their procedures' features. Additionally, a team analyzed their baseline electrocardiograms (ECGs) using the EASY-WPW, Pambrun, and St. George algorithms. The sensitivity, specificity, PPV, and NPV of these algorithms were then calculated based on the location of the accessory pathways identified during the patients’ ablation treatments. Results The median age of the patients in this study was 33 years (18 - 79). Among them, 65 patients (53.3%) were male (Table 1). Ablation treatment was conducted using a 3D mapping system for all included patients, considering only those who achieved acute procedural success for analysis. The most frequently observed accessory pathway localization was the posteroseptal region of the tricuspid annulus, found in 48 patients (39.3%). Regarding the accuracy of accessory pathway prediction, the EASY-WPW, Pambrun, and St. George algorithms demonstrated correct localization rates of 81%, 72%, and 62%, respectively. The efficacy of these predictions varied according to the specific localization of the accessory pathways (Table 2). Conclusion This study highlights the limitations of previously published algorithms in predicting the localization of accessory pathways in WPW syndrome. The notably lower success rates observed in our research, as compared to earlier studies, might be attributed to variations in how localization is defined across studies, differences in the interpretation of these algorithms by users, or evolving definitions of localization resulting from advancements in 3-dimensional mapping systems. Given these findings, there is a clear need for the development of new algorithms that incorporate current localization definitions and are validated in larger patient cohorts.

Financing the future: Asymmetric association between green investment and electric vehicles

Green investment in electric vehicles represents a pivotal shift towards a sustainable future, promising to revolutionize our transportation systems while significantly reducing greenhouse gas emissions. This research aims to probe the linkage between green investment and electric vehicles across the top 10 economies with the highest electric vehicle adoption rates (China, USA, Norway, Germany, UK, France, Portugal, Netherlands, Belgium, and South Korea). Unlike earlier studies that primarily utilized panel data methods and overlooked the individual nuances of each country, our investigation employs the advanced ‘Quantile-on-Quantile’ technique. This novel approach enables us to delve into the relationships between variables within each specific country, thereby improving the precision of our analysis. As a result, this study provides a comprehensive global viewpoint, revealing nuanced findings about each nation's distinct characteristics. The study's findings express a positive connection between green investment and the electric vehicle stock in various segments of the sample economies. Furthermore, this research highlights diverse trends in these connections within different nations. The results emphasize policymakers’ need to conduct comprehensive evaluations and develop effective strategies to address changes in both green investment and electric vehicles.

Effect of relative timescale on a system of particles sliding on a fluctuating energy landscape: Exact derivation of product measure condition.

We consider a system of hardcore particles advected by a fluctuating potential energy landscape, whose dynamics is in turn affected by the particles. Earlier studies have shown that as a result of two-way coupling between the landscape and the particles, the system shows an interesting phase diagram as the coupling parameters are varied. The phase diagram consists of various different kinds of ordered phases and a disordered phase. We introduce a relative timescale ω between the particle and landscape dynamics, and study its effect on the steady state properties. We find there exists a critical value ω=ω_{c} when all configurations of the system are equally likely in the steady state. We prove this result exactly in a discrete lattice system and obtain an exact expression for ω_{c} in terms of the coupling parameters of the system. We show that ω_{c} is finite in the disordered phase, diverges at the boundary between the ordered and disordered phase, and is undefined in the ordered phase. We also derive ω_{c} from a coarse-grained level description of the system using linear hydrodynamics. We start with the assumption that there is a specific value ω^{*} of the relative timescale when correlations in the system vanish, and mean-field theory gives exact expressions for the current Jacobian matrix A and compressibility matrix K. Our exact calculations show that Onsager-type current symmetry relation AK=KA^{T} can be satisfied if and only if ω^{*}=ω_{c}. Our coarse-grained model calculations can be easily generalized to other coupled systems.

Experiences of living with idiopathic pulmonary fibrosis in relation to physical activity - “How the hills became steeper and steeper”: a qualitative interview study

IntroductionIdiopathic pulmonary fibrosis (IPF) is a progressive disease presenting with symptoms like dyspnoea, dry cough, and fatigue, which affect physical function and quality of life. No earlier qualitative studies have investigated physical activity in IPF. This study aims to explore experiences of living with IPF in relation to physical activity.Materials and methodsQualitative interviews were conducted with 14 participants living with IPF. The participants were 77 years old (range: 56–86) and diagnosed with IPF between 2 and 9 years ago. The analysis was performed by qualitative content analysis according to Graneheim and Lundman.ResultsThe results indicated that life and one’s ability to be physically active is affected by IPF. Despite this, it seems possible to navigate past obstacles, which was illustrated by an overall theme: “My life is constrained, but I am hanging on”. Two major categories cover topics of IPF being a life changing diagnosis with changes in self-image and changed future plans regarding physical activity, as well as life. Physical activity was perceived to be challenging, yet in many ways used as a strategy, developed to manage life.ConclusionsIPF affects physical activity as well as life, from onset onwards. By developing strategies for facilitating physical activity as well as identifying barriers, it seems possible to maintain an active life despite the disease. The healthcare system needs to create support systems that meet different needs during different phases of the disease.Trial registration“FoU in Sweden” Research and Development in Sweden (id: 227081).

Multitasking across the lifespan in different task contexts

We assessed lifespan development of multitasking in a sample of 187 individuals aged 8–82 years. Participants performed a visuo-spatial working memory (VSWM) task together with either postural control or reaction time (RT) tasks. Using criterion-referenced testing we individually adjusted difficulty levels for the VSWM task to control for single-task differences. Age-differences in single-task performances followed U-shaped patterns with young adults outperforming children and older adults. Multitasking manipulations yielded robust performance decrements in VSWM, postural control and RT tasks. Presumably due to our adjustment of VSWM challenges, costs in this task were small and similar across age groups suggesting that age-differential costs found in earlier studies largely reflected differences already present during single-task performance. Age-differences in multitasking costs for concurrent tasks depended on specific combinations. For VSWM and RT task combinations increases in RT were the smallest for children but pronounced in adults highlighting the role of cognitive control processes. Stabilogram diffusion analysis of postural control demonstrated that long-term control mechanisms were affected by concurrent VSWM demands. This interference was pronounced in older adults supporting concepts of compensation or increased cognitive involvement in sensorimotor processes at older age. Our study demonstrates how a lifespan approach can delineate the explanatory scope of models of human multitasking.

Associations between tobacco smoking status and patch test results-A cross-sectional pilot study from the Information Network of Departments of Dermatology (IVDK).

Earlier studies suggested a potential association between tobacco smoking and nickel sensitization, but little is known about other contact allergens. To investigate the association of smoking status and contact sensitizations as well as subtypes of dermatitis, and to analyse the sensitization profiles of tobacco smokers. Within the Information Network of Departments of Dermatology (IVDK), we performed a cross-sectional multicentre pilot study comprising 1091 patch-tested patients from 9 departments, comparing 541 patients with a history of cigarette smoking (281 current and 260 former smokers) with 550 never-smokers. We could not confirm the previously reported association between nickel sensitization and tobacco smoking. Moreover, sensitizations to other allergens, including colophony, fragrance mix I, Myroxylon pereirae and formaldehyde, were not increased in cigarette smokers compared with never smokers. Hand dermatitis (50.6% vs. 33.6%) and occupational cause (36.2% vs. 22.5%) were significantly more frequent among cigarette smokers compared with never-smokers as shown by non-overlapping 95% confidence intervals. Although our study does not allow a firm conclusion on whether smoking status contributes to certain contact sensitizations, it confirms an association of smoking with hand dermatitis and occupational cause.

Molecular mechanism of choline and ethanolamine transport in humans

Human feline leukaemia virus subgroup C receptor-related proteins 1 and 2 (FLVCR1 and FLVCR2) are members of the major facilitator superfamily1. Their dysfunction is linked to several clinical disorders, including PCARP, HSAN and Fowler syndrome2–7. Earlier studies concluded that FLVCR1 may function as a haem exporter8–12, whereas FLVCR2 was suggested to act as a haem importer13, yet conclusive biochemical and detailed molecular evidence remained elusive for the function of both transporters14–16. Here, we show that FLVCR1 and FLVCR2 facilitate the transport of choline and ethanolamine across the plasma membrane, using a concentration-driven substrate translocation process. Through structural and computational analyses, we have identified distinct conformational states of FLVCRs and unravelled the coordination chemistry underlying their substrate interactions. Fully conserved tryptophan and tyrosine residues form the binding pocket of both transporters and confer selectivity for choline and ethanolamine through cation–π interactions. Our findings clarify the mechanisms of choline and ethanolamine transport by FLVCR1 and FLVCR2, enhance our comprehension of disease-associated mutations that interfere with these vital processes and shed light on the conformational dynamics of these major facilitator superfamily proteins during the transport cycle.

Why Female Presence on Boards is Often Ignored in Firms? Empirical Evidence from Emerging Economies

The study examined the effect of the presence of female directors in the board and other board characteristics like board size, independence of directors, CEO duality, and meetings attended by directors. The Panel data analysis is used by taking a sample of 21 Pakistani banks and 52 Chinese banks. The results of this study reveal that some board features like board size and independence of directors have a significant effect on banks’ performance both in Pakistan and China. But other board variables like CEO duality and female director presence have insignificant impact on the performance of Pakistani and Chinese banks. These results are consistent with earlier studies.

Top IT Challenges in ARL Libraries

The practice of information technology (IT) in academic libraries is changing rapidly, not only with new and evolving developments in the technologies themselves but also with the organization and management of IT at both the library and institution levels. This study presents the results of an online survey of Association of Research Libraries (ARL) academic library members to identify the biggest challenges they perceive in the area of information technology organization and management. This article compares their responses with challenges reported in earlier studies to identify new and changing trends as well as ongoing challenges that remain.

A route to fabricate low resistance joints between Eu–Ba–Cu–O bulk, single grain superconductors

The fabrication of large (RE)–Ba–Cu–O single grains [(RE)BCO], where RE = Y, Gd, Eu or Sm, with the complex geometries required for many practical applications is currently limited by the time intensive, complex nature of the grain growth process. In addition, the shapes achievable using established melt processing techniques, such as top seeded melt growth, are constrained significantly by the limited number of post-processing techniques readily available. Machining of these materials is also difficult given their ceramic-like mechanical properties, which makes them both brittle and hard. A potential alternative to the slow and inflexible melt growth processes is to join many small, single grains to form one large composite grain, connected by electrically and mechanically high-performance joints. A reliable joining technique would also greatly reduce the need for post-growth machining processes. In this work we extend our previous investigation of the use of single grain YBCO-Ag as an intermediate joining material to achieve effective and reliable superconducting joints between EuBCO-Ag bulk, single grain superconductors. The technique reported in the earlier studies requires limited specialist equipment and does not require tight process parameter control, since there is no need to re-grow the joining material at the intergrain interface. This technique is of particular interest given that the difference between the peritectic temperatures of the bulk superconductor and the intermediate joining material is large. We report the properties of seven joints engineered at different joining temperatures. The trapped field properties of the resulting joined samples were measured and the microstructure at the position of the joint examined. We demonstrate that this simple and the rapid joining technique makes it possible to manufacture composite grains in an industrially important (RE)BCO bulk superconductor with comparable superconducting properties to those of a single grain of similar dimensions.

Investigation of Carbon Fiber Reinforced Polymer Concrete Reinforcement Ageing Using Microwave Infrared Thermography Method

This study presents the utilization of the microwave infrared thermography (MIRT) technique to identify and analyze the defects in the carbon-fiber-reinforced polymer (CFRP) composite reinforcement of concrete specimens. At first, a set of numerical models was created, comprising the broadband pyramidal horn antenna and the analyzed specimen. The utilization of the system operating at a power of 1000 W in a continuous mode, operating at frequency of 2.45 GHz, was analyzed. The specimen under examination comprised a compact concrete slab that was covered with an adhesive layer and, thereafter, topped with a layer of CFRP. An air gap represented a defect at the interface between the concrete and the CFRP within the adhesive layer. In the modeling stage, the study investigated three separate scenarios—a sample with no defects, a sample with a defect located at the center, and a sample with a numerous additional random defects located at the rim of the CFRP matte—to analyze the effect of the natural reinforcement degradation in this area. The next phase of the study involved conducting experiments to confirm the results obtained from numerical modeling. In the experiments, the concrete sample aged for 10 years with the defect in the center and naturally developed defects at the CFRP rim was used. The study employed numerical modeling to explore the phenomenon of microwave heating in complex structures. The aim was to assess the chosen antenna design and identify the most effective experimental setup. These conclusions were subsequently confirmed through experimentation. The observations made during the heating process were particularly remarkable since they deviated from earlier studies that solely conducted measurements of the sample post-heating phase. The findings demonstrate that MIRT has the capacity to be employed as a technique for detecting flaws in concrete structures reinforced with CFRP.

Phylogeny of the Microspermae-I

The paper discusses the comparative floral morphology of the Burmanniaceae, the Apostasiaceae and the Orchidaceae on the basis of an earlier study of this author on Burmannia pusilla. The affinities and the evolutionary problem of the taxa concerned are discussed and it is thought that the Englerian arrangement of retaining the three families under a single order to be more in accordance with the facts. The need for further studies to adduce more evidence in connection with the phylogeny of the Microspermae as a whole is pointed out.

Lipopolysaccharide with long O-antigen is crucial for Salmonella Enteritidis to evade complement activity and to facilitate bacterial survival in vivo in the Galleria mellonella infection model

Bacterial resistance to serum is a key virulence factor for the development of systemic infections. The amount of lipopolysaccharide (LPS) and the O-antigen chain length distribution on the outer membrane, predispose Salmonella to escape complement-mediated killing. In Salmonella enterica serovar Enteritidis (S. Enteritidis) a modal distribution of the LPS O-antigen length can be observed. It is characterized by the presence of distinct fractions: low molecular weight LPS, long LPS and very long LPS. In the present work, we investigated the effect of the O-antigen modal length composition of LPS molecules on the surface of S. Enteritidis cells on its ability to evade host complement responses. Therefore, we examined systematically, by using specific deletion mutants, roles of different O-antigen fractions in complement evasion. We developed a method to analyze the average LPS lengths and investigated the interaction of the bacteria and isolated LPS molecules with complement components. Additionally, we assessed the aspect of LPS O-antigen chain length distribution in S. Enteritidis virulence in vivo in the Galleria mellonella infection model. The obtained results of the measurements of the average LPS length confirmed that the method is suitable for measuring the average LPS length in bacterial cells as well as isolated LPS molecules and allows the comparison between strains. In contrast to earlier studies we have used much more precise methodology to assess the LPS molecules average length and modal distribution, also conducted more subtle analysis of complement system activation by lipopolysaccharides of various molecular mass. Data obtained in the complement activation assays clearly demonstrated that S. Enteritidis bacteria require LPS with long O-antigen to resist the complement system and to survive in the G. mellonella infection model.