Kinematic Performance Measures and Optimization of Parallel Kinematics Manipulators: A Brief Review

This chapter covers a number of kinematic performance indices that are instrumental in designing parallel kinematics manipulators. These indices can be used selectively based on manipulator requirements and functionality. This would provide the very practical tool for designers to approach their needs in a very comprehensive fashion. Nevertheless, most applications require a more composite set of requirements that makes optimizing performance more challenging. The later part of this chapter will discuss single-objective and multi-objectives optimization that could handle certain performance indices or a combination of them. A brief description of most common techniques in the literature will be provided

Predictors of Human Immunodeficiency Virus Knowledge among Jordanian Youths

Objectives: Understanding factors associated with the level of human immunodeficiency virus (HIV) knowledge acquisition is crucial to inform preventative programmes for young people. This study examines predictors of HIV knowledge among Jordanian youths. Methods: A cross-sectional survey was conducted among 8,129 youths aged between 14 and 25 years randomly selected from schools representing each of the 12 governorates of Jordan. A total of 50% of respondents were female and, on average, 17 years old. Participants completed a self-administered questionnaire covering sociodemographic characteristics, HIV knowledge, gender awareness, exposure to and favourable attitudes toward risky behaviours. Results: On a 13-item HIV knowledge test, participants answered an average of 7 questions correctly (mean = 7.21; standard deviation = 2.63). Female respondents from rural areas demonstrated significantly lower levels of HIV knowledge, while college and university students demonstrated higher levels. HIV knowledge differed significantly by sources of information, with peeracquired information associated with more accuracy, while HIV information from parents or health centres was associated with a lower score. Youths with more egalitarian gender views also demonstrated higher knowledge levels, whereas youths approving of drug use showed lower levels of HIV knowledge. Conclusion: HIV education programmes in Jordan should focus on females and youths living in rural areas. Educational institutions have been shown to be effective in providing accurate information to students, while parents and health professionals should also be included in HIV prevention programmes in order to reduce misconceptions and raise the level of HIV knowledge among Jordanian youths

Internet Providers’ Liability for Illegal Content A Study in French and European E-commerce Law

The advent of the computer and the Internet has lead to huge technological developments in contact means. However, some problems have emanated from such developments such as the misuse of the Internet in the form of publishing illegal and harmful content. As a result, some questions have been raised such as, whether Internet providers can be held liable for such publishing, on what such liability maybe be based, and what standards maybe applied to Internet providers’ liability. This study aims to identify the conditions under which Internet providers can be held liable for providing illegal, harmful conten

Influence of carbon nanotubes on printing quality and mechanical properties of 3D printed cementitious materials

This paper presents the impact of incorporating carbon nanotubes (CNTs) into the 3D printing of cementitious materials, along with the effective dispersion of CNTs. Compared to the control mix, adding CNTs with superplasticizer significantly enhanced the printing quality by reducing the error in height of two-layers from 38% to 30% and an 81% enhancement in the buildability. Moreover, rheology properties revealed shear-thinning behaviour with lower viscosity, resulting in improved flowability. The progressive increase in CNT concentrations up to 0.2% yielded a noteworthy improvement in the mechanical properties. At 28 days, the incorporation of 0.2% CNTs resulted in a significant increase in the flexural strength, compressive strength, and Young's modulus by 99%, 72%, and 43%, respectively, compared to the mix containing silica fume. Microstructural investigation of the CNT-cement matrix revealed nanoscale crack bridges formed by CNTs, reinforcing the cementitious material and improving its mechanical properties.</p

The synthetic cannabinoids menace: a review of health risks and toxicity

Synthetic cannabinoids (SCs) are chemically classified as psychoactive substances that target the endocannabinoid system in many body organs. SCs can initiate pathophysiological changes in many tissues which can be severe enough to damage the normal functionality of our body systems. The majority of SCs-related side effects are mediated by activating Cannabinoid Receptor 1 (CB1R) and Cannabinoid Receptor 2 (CB2R). The activation of these receptors can enkindle many downstream signalling pathways, including oxidative stress, inflammation, and apoptosis that ultimately can produce deleterious changes in many organs. Besides activating the cannabinoid receptors, SCs can act on non-cannabinoid targets, such as the orphan G protein receptors GPR55 and GPR18, the Peroxisome Proliferator-activated Receptors (PPARs), and the Transient receptor potential vanilloid 1 (TRPV1), which are broadly expressed in the brain and the heart and their activation mediates many pharmacological effects of SCs. In this review, we shed light on the multisystem complications found in SCs abusers, particularly discussing their neurologic, cardiovascular, renal, and hepatic effects, as well as highlighting the mechanisms that intermediate SCs-related pharmacological and toxicological consequences to provide comprehensive understanding of their short and long-term systemic effects. Graphical Abstract: [Figure not available: see fulltext.].The publication of this article was funded by Qatar National Library

Performance evaluation of parallel manipulators for milling application

This paper focuses on the performance evaluation of the parallel manipulators for milling of composite materials. For this application the most significant performance measurements, which denote the ability of the manipulator for the machining are defined. In this case, optimal synthesis task is solved as a multicriterion optimization problem with respect to the geometric, kinematic, kinetostatic, elastostostatic, dynamic properties. It is shown that stiffness is an important performance factor. Previous models operate with links approximation and calculate stiffness matrix in the neighborhood of initial point. This is a reason why a new way for stiffness matrix calculation is proposed. This method is illustrated in a concrete industrial problem

Prevalence and correlates of autism spectrum disorder in Qatar: a national study

Background Few epidemiological data on autism spectrum disorders (ASD) exist for Arabic countries. We conducted the first survey of ASD in Qatar, a population with high consanguinity level. Methods This cross‐sectional survey was conducted from 2015 to 2018 in Qatar school‐age children (N = 176,960) from national and immigrant families. Children diagnosed with ASD were identified through medical centers and special needs schools. Records were abstracted and supplemented by parental interviews. Additionally, children attending 93 schools were screened; ASD case status was confirmed in random samples of screen‐positive and screen‐negative children. Prevalence was estimated after taking into account different sampling fractions and participation rates at each survey phase. Results One thousand three hundred and ninety‐three children already diagnosed with ASD were identified. Among 9,074 school survey participants, 760 screen‐negative children and 163 screen‐positive children were evaluated; 17 were confirmed to have ASD including five children newly diagnosed. Prevalence was 1.14% (95% CI: 0.89–1.46) among 6‐ to 11‐year‐olds. ASD was reported in full siblings/extended relatives in 5.9% (95% CI: 0.042–0.080)/11.8% (95% CI: 0.095–0.146) families. First‐degree consanguinity in Qatari cases (45%) was comparable to known population levels. Among 844 ASD cases (mean age: 7.2 years; 81% male), most children experienced language delay (words: 75.1%; phrase speech: 91.4%), and 19.4% reported developmental regression. At the time of the survey, persisting deficits in expressive language (19.4%) and peer interactions (14.0%) were reported in conjunction with behavioral problems (ADHD: 30.2%; anxiety: 11.0%). In multivariate logistic regression, ASD severity was associated with parental consanguinity, gestational diabetes, delay in walking, and developmental regression. Conclusions ASD prevalence in Qatar is consistent with recent international studies. The methods employed in this study should help designing comparable surveys in the region. We estimated that 187,000 youths under age 20 have ASD in Gulf countries. This figure should assist in planning health and educational services for a young, fast‐growing population.The study was supported by the Qatar National Research Fund. The sponsor had no role in the design and conduct of the study, or the collection, management, analysis, and interpretation of the data, or in the preparation, review, or approval of the manuscript, and in the decision to submit the manuscript for publication. The authors thank all the independent and private schools that have participated in the SCQ screening phase. The authors thank the Ministry of Public Health and the Ministry of Education for providing their team with the data required throughout the study. The authors would like to express our gratitude to the psychological services team at the Shafallah Center for Children with Disabilities, as well as Dr. Irshad Shafeullah and Dr. Zakariah Al-Sayed for their support in patient recruitment. The authors also thank our colleagues from QBRI: Dr. Hatem Al-Shanti for his assistance in patient phenotyping, and Mr. Yasser Al-Sarraj and Ms. Hamda AlMutawwa for their support with patient recruitment. The authors thank Dr. Hanaa Massoud for assisting with patient recruitment through the clinic at the Child Development Center in Rumailah Hospital. The authors would also like to express their appreciation to the QBRI administration team for their assistance with planning and logistics pertaining to research-related training sessions and research collaborator visits. Additionally, the authors would like to thank all of the special needs centers and clinics which collaborated with us to provide data needed for the high probability cases; Shafallah Center for Children with Disabilities, Hamad Medical Corporation, Child Development Center ? Rumailah Hospital, Child Development Center-Private, Renad Academy, Al-Tamakun school, Step by Step Center, Qatar Institute for Speech and Hearing, and Hope Center. The authors also thank the HBKU Sponsored Research Office for the support provided throughout the research funding period.?K.R. and the OHSU Biostatistics & Design Program was partially supported by the Oregon Clinical and Translational Research Institute (OCTRI) through OHSU Clinical & Translational Science Awards (CTSA UL1TR0002369) National Consortium. The authors are immensely grateful to the families and their children for their time and participation in any of the phases of the research. F.A. and E.F. designed the research plan. F.A., M.A., and E.F. applied for funding. F.A., H.A., S.E., I.G., M.T., M.A., M.K., N.A.A., M.A., A.H.S., and L.D. organized the data collection. F.A., H.A., S.E., and I.G. completed data entry and cleaning, and performed initial data analyses with M.A. E.F. performed data and statistical analyses. K.R. provided biostatistical advice. E.F., F.A., and I.G. wrote the manuscript. All authors reviewed and approved the manuscript. The authors have declared that they have no competing or potential conflicts of interest.Scopu

The impact of financial technology on bank performance in Arabian countries

Banking operations have always evolved in tandem with developing technologies in all fields, providing new services to customers and facilitating easier banking transactions. Many banks have adopted modern financial technology, which has immensely impacted their financial performance, often linked to their operation markets and client bases. This study aims to examine the relationship between financial technology and bank performance using panel data for 21 Arabian banks, from Bahrain, Jordan, Kuwait, Oman, Qatar, Saudi Arabia, and the United Arab Emirates, from 2015 to 2022. Financial technology was determined by the frequency with which digitalization terminology appeared in annual reports. Bank performance is measured by return on assets and return on equity. Ordinary least squares and two-stage least squares were applied to achieve the objective. The findings reveal that financial technology positively impacts the return on assets for Arabian banks, where a one-unit increase in fintech causes a 0.37 increase in ROA. In addition, financial technology positively impacts return on equity for Arabian banks, where a one-unit increase in fintech leads to a 0.29 increase in ROE. To confirm the study results, robustness was examined for the regression results using sub-period analysis before and during COVID-19. The results obtained using the two sub-periods show that financial technology positively impacts banks’ financial performance in the two sub-periods before and during COVID-19. In addition, financial technology’s impact on financial performance in model 1 and model 2 during COVID-19 (0.78 and 0.47) is higher than its impact before COVID-19 (0.49 and 28)

Circular economy in Egypt: an overview of the current landscape and potential for growth

This paper provides an overview of the circular economy in Egypt. With the country facing significant environmental challenges, a circular economy approach can offer sustainable solutions to Egypt's environmental challenges by addressing issues like limited resources, waste generation, and a growing population in an eco-friendly and long-term perspective. This research employs a mixed-methods approach, including a literature review, surveys, and consultations with key stakeholders. The analysis reveals that although there are numerous challenges to establishing a circular economy in Egypt, such as limited understanding, insufficient government backing, and inadequate infrastructure, there are also opportunities, such as increasing demand for eco-friendly goods and services, as well as a receptive business environment. The paper recommends various policy and practical interventions to overcome these barriers and capitalize on these opportunities, including increasing awareness and understanding of the circular economy, developing supportive programs and regulations, investing in infrastructure and technology, and fostering stakeholder collaboration. This paper provides valuable insights into the potential for a circular economy in Egypt and the steps that can be taken to create a more sustainable future for the country. As such, it will interest policymakers, researchers, and practitioners working in the sustainability and environmental management field. The successful implementation of a circular economy in Egypt will require collective efforts from stakeholders to promote long-term sustainability and environmental stewardship