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Mathematica Pannonica
Authors:
Muhammad T. Tajuddin
,
Usama A. Aburawash
, and
Muhammad Saad

This paper introduces and examines the concept of a *-Rickart *-ring, and proves that every Rickart *-ring is also a *-Rickart *-ring. A necessary and sufficient condition for a *-Rickart *-ring to be a Rickart *-ring is also provided. The relationship between *-Rickart *-rings and *-Baer *-rings is investigated, and several properties of *-Rickart *-rings are presented. The paper demonstrates that the property of *-Rickart extends to both the center and *-corners of a *-ring, and investigates the extension of a *-Rickart *-ring to its polynomial *-ring. Additionally, *-Rickart *-rings with descending chain condition on *-biideals are studied, and all *-Rickart (*-Baer) *-rings with finitely many elements are classified.

Open access
Journal of Behavioral Addictions
Authors:
Damian van der Neut
,
Margot Peeters
,
Meyran Boniel-Nissim
,
Helena Jeriček Klanšček
,
Leila Oja
, and
Regina van den Eijnden
Open access
Physiology International
Authors:
Antonia Kellnar
,
Stefan Brunner
,
Anna Strüven
,
Georges Weis
,
Korbinian Lackermair
, and
Magda Haum

Abstract

The global temperature rise will have extensive consequences on our organ systems, but hypohydration caused by reduced water intake or increased water loss through sweating plays the most relevant role. Many studies have already demonstrated the association between hypohydration and impaired exercise performance, but data related to the cardiac burden of hypohydration are scarce. This study is a sub-investigation of our large, prospective, self-controlled trial on the effects of hypohydration on cardiopulmonary exercise capacity with previously published results. In the current sub-study, we analyzed the impact of hypohydration on cardiac burden in this cohort of fifty healthy, recreational athletes during cardiopulmonary exercise test.

Therefore, each participant underwent cardiopulmonary exercise test with a standardized ramp protocol twice, once in hypohydrated state and once in euhydrated state as control, and the cardiac markers Troponin T, NT-pro-BNP and Chromogranin A were measured before and after the exercise test at each state. Mean age was 29.7 years and 34% of probands were female. Hypohydration led to a reduced body water, a significant decrease in oxygen uptake and lower levels of power output. Yet, Troponin T, NT-proBNP, Chromogranin A and lactate levels did not significantly differ between the two conditions.

In this study cohort, decreased exercise capacity during hypohydration was more likely due to impaired cardiac output with diminished plasma volume rather than measurable cardiac stress from fluid deprivation. However, whether these data are generalizable to a diseased cohort is left unanswered and should be addressed in future randomized controlled trials.

Restricted access
Journal of Behavioral Addictions
Authors:
Catherine Tulloch
,
Nerilee Hing
,
Matthew Browne
,
Alex M. T. Russell
,
Matthew Rockloff
, and
Vijay Rawat

Abstract

Aims

Understanding how gambling harm is distributed is essential to inform effective harm reduction measures. This first national Australian study of gambling harm-to-self examined the extent, distribution, risk factors, and health related quality of life (HRQoL) impacts of this harm.

Methods

A Random Digit Dialling sample of 15,000 Australian adults was weighted to key population variables. Key measures included the Gambling Harms Scale-10 (GHS-10), PGSI, SF-6D, gambling behaviours, and demographics. Analyses included ordinal logistic regression.

Results

Amongst gamblers, 14.7% reported harm on the GHS-10, including 1.9% reporting high-level harm. While high-level harm occurred mainly in the problem gambling group (77.3%), other PGSI groups accounted for most of the more prevalent low (98.5%) and moderate (87.2%) harms reported. Proximal predictors of greater harm were use of online gambling and more frequent gambling on electronic gaming machines (EGMs), race betting sports betting, poker, skin gambling, scratchies, and loot box purchasing. Distal predictors were being younger, male, single, Aboriginal or Torres Strait Islander, and speaking a non-English language at home. At the population level, the greatest aggregate HRQoL impacts were amongst lower-risk gamblers, confirming the results of other studies regarding the ‘prevention paradox’.

Conclusions

The distribution of harm across gambler risk groups indicates the need for preventive measures, not just interventions for problem gambling. Reducing harm requires modifying product features that amplify their risk, especially for EGMs, race betting and sports betting that are both inherently risky and widely used. Gambling harm exacerbates health disparities for disadvantaged and vulnerable groups, requiring targeted resources and support.

Open access

Abstract

Fused deposition modeling (FDM) 3D printing is widely utilized for producing thermoplastic components with functional purposes. However, the inherent mechanical limitations of pure thermoplastic materials necessitate enhancements in their mechanical characteristics when employed in certain applications. One strategy for addressing this challenge involves the incorporation of reinforcement materials, such as carbon fiber (CF), within the thermoplastic matrix. This approach leads to the creation of carbon fiber-reinforced polymer composites (CFRPs) suitable for engineering applications. The utilization of CFRPs in 3D printing amalgamates the benefits of additive manufacturing, including customization, cost-effectiveness, reduced waste, swift prototyping, and accelerated production, with the remarkable specific strength of carbon fiber. This study encompasses tensile and compressive testing of distinct material compositions: recycled polylactic acid (rPLA), PLA enriched with 10 wt.% carbon fiber, pristine polyethylene terephthalate glycol (PETG), and PETG bolstered with 10 wt.% carbon fiber. Tensile tests adhere to the ASTM D3039 standard for specimens of rectangular shape, while the ASTM D695 standard governs the compressive testing procedures. Additionally, an inquiry into the influence of the primary 3D printing build orientation parameter on the tensile and compressive strengths of diverse materials was conducted. The outcomes reveal that rPLA exhibits superior mechanical properties in both tensile and compressive tests, irrespective of flat or on-edge build orientations. In the context of tensile strength analysis, it is noteworthy that rPLA demonstrated a superior performance, surpassing CFPLA by 30% in flat orientation and exhibiting a remarkable 39.2% advantage in on-edge orientation. Moreover, PLA reinforced with carbon fiber exhibits superior tensile and compressive properties compared to its PETG counterpart. A comparative analysis between CFPLA and CF-PETG indicates that CF-PLA demonstrates higher tensile strengths, with increases of 26.6 and 27.6% for flat and on-edge orientations, respectively. In the context of compressive strength analysis, rPLA surpassed CFPLA, PETG, and CF-PETG by 23.7, 53, and 67%, respectively. Intriguingly, the findings indicate that the incorporation of 10 wt.% carbon fiber diminishes the tensile and compressive properties in comparison to pure PETG.

Open access

Abstract

The manufacture of High-Performance Concrete (HPC) in bridge deck construction is part of an experimental framework that is also developing in the numerical domain to fill the existing gaps in understanding its behavior. However, the numerical modeling of HPC for bridge decks remains largely under-explored. It is precisely this gap that has sparked our interest in this research area, thus giving our work its innovative character.

This study primarily aims to deepen the understanding of the behavior of HPC bridge decks while manufacturing an efficient and economical HPC using local materials possessing very high properties (mechanical, physical, elastic, durability, and implementation) and advanced numerical modeling. This modeling has enabled us to study the behavior of HPC bridge decks in relation to cracking through the Extended Finite Element Method (X-FEM), an innovative solution that enables the modeling of discontinuities without complicating the process. This has been confirmed by the quality of the results, which show an excellent correlation with experimental data, underscoring the accuracy of the modeling. These results also reveal that the use of HPC in bridge construction can significantly reduce degradation risks while enhancing their performance. Consequently, the adoption of HPC stands out as a beneficial strategy, not only to minimize bridge degradation but also to extend their durability.

Open access

Abstract

Spatial data management is crucial for applications like urban planning and environmental monitoring. While traditional relational databases are commonly used, they struggle with large and complex spatial data. NoSQL databases provide support for unstructured data and scalability. This article compares the performance and disk space usage of SQL Server (a relational database) and MongoDB (NoSQL database) using an open-source library. Experiments conducted with the OpenStreetMap dataset from Central America show that the MongoDB database outperformed the relational SQL Server database in most cases, offering practical advantages for spatial data management in Geographic Information System applications.

Open access

The Geometric Construction of Hexagonal Apses in Mediaeval Hungary

Hatszögű apszisok geometriai szerkesztése a középkori Magyarország területén

Építés - Építészettudomány
Authors:
Fanni Budaházi
and
Balázs Halmos

Geometric construction in Gothic architecture has been a popular subject of research for centuries. The use and extent of quadrature and triangulation grids has long been debated, as the few architectural drawings that survived from the era do not indicate the construction process. Modern surveying methods, however, allow us to inspect the exact geometry of a building with all its irregularities – in the case of this article we use 3D point clouds created by laser scanning, from which accurate measurements can be taken.

In our study we analyse four churches from mediaeval Hungary: the Franciscan church of Szeged-Alsóváros, the fortified church of Cincu (RO, Nagysink/Großschenk), the Franciscan church of GyöngyösAlsóváros and the fortified church of Mediaș (RO, Medgyes/Mediasch). Each of these are built with elongated choirs and approximately hexagonal apses. We explore the possible construction systems of these buildings and compare them to each other. We aim to present the similarities and differences between them and to offer likely explanations of their irregularities. Moreover, we propose the significance of construction circles used for creating a triangulation grid.

Open access

Abstract

This study is devoted to condition-based maintenance using vibration analysis. It proposes a numerical and experimental methodology to assist in the detection and vibratory monitoring of chipping faults on gear teeth.

The aim of this work is to model the dynamic behavior of the gear link and to treat the vibration behavior of gear flaws theoretically and experimentally. This article is going to study the case of a breast gear, a defect located on the wheel, another defect on the pinion and the wheel and the insufficient center distance defect based on experiments carried out on a test bench manufactured in the laboratory.

Restricted access

Abstract

Acquired benign tracheoesophageal fistulas and bronchoesophageal fistulas (TEF) are typically associated with granulomatous mediastinal infections, 75% of which are iatrogenic. Candida albicans and Actinomyces are commonly occurring organisms, but are uncommon etiologies of TEF. Normal colonization and the slow growth characteristics of some species of these agents rarely result in infection, mycetoma, and broncholithiasis, and thus, delays in diagnosis and treatment are likely. Few reports describe C. albicans or Actinomyces spp. as the etiology of TEF or broncholithiasis. Herein, we report a case of benign acquired TEF secondary to coinfection of Candida and Actinomyces complicated by the formation of an actinomycetoma and broncholithiasis and a comprehensive literature review to highlight the unique nature of this presentation and offer a diagnostic algorithm for diagnosis and treatment of TEFs. Following a presentation of three months of productive cough, choking sensation, night sweats, and weight loss, a bronchoscopy revealed a fistulous connection between the esophagus and the posterior right middle lobe. Pathology identified a calcified fungus ball and a broncholith secondary to the co-infection of Candida and Actinomyces. This unique presentation of Candida and Actinomyces co-infection and the associated diagnostic algorithm are presented as education and a useful tool for clinicians.

Open access