Post-materialistic values and entrepreneurial intention-The Case of Saudi Arabia

Purpose: The purpose of this paper is to investigate how cultural values influence the entrepreneurial process. It conceptualises the relationship between post-materialistic values and entrepreneurial intention to explain low entrepreneurial activity. Design/methodology/approach: The study was conducted in Saudi Arabia with non-entrepreneurs. An online survey returned 405 valid questionnaires, representing a 27 per cent response rate. The data were analysed using partial least structural equation modelling. Findings: The paper identifies key factors that explain the influence of changing cultural values on entrepreneurial activity. The results show that post-materialistic values influence entrepreneurial intention by decreasing desirability and entrepreneurial self-efficacy. Research limitations/implications: The study conceptualises the interplay between cultural values and entrepreneurial intention in Saudi Arabia. Further insights can be developed by comparing Saudi Arabia with other countries. The study was conducted as a “snapshot” of the current situation of entrepreneurship in Saudi Arabia with a cross-sectional survey design. Practical implications: The paper holds important implications for entrepreneurship educators when addressing unsupportive cultures for entrepreneurial activity. Cultural and motivational approaches are suggested. While the former focuses on aspects that encourage the desire and confidence to start a business, the latter involves encouraging setting venture creation as a goal. Originality/value: Previous studies indicated that post-materialistic values negatively influence entrepreneurship; this paper contributes further by exploring how this relationship manifests by exploring the intervening factors between post-materialistic values and entrepreneurial intention. It advances entrepreneurship research by investigating deep assumptions underlying the formulation of entrepreneurial intentions. It also responds to the need to understand the difference in the levels of entrepreneurial activity across countries

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8–13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05–6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50–75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life. Funding Pfizer, Amgen, Merck Sharp & Dohme, Sanofi–Aventis, Daiichi Sankyo, and Regeneron

Familial hypercholesterolaemia in children and adolescents from 48 countries: a cross-sectional study

Background: Approximately 450 000 children are born with familial hypercholesterolaemia worldwide every year, yet only 2·1% of adults with familial hypercholesterolaemia were diagnosed before age 18 years via current diagnostic approaches, which are derived from observations in adults. We aimed to characterise children and adolescents with heterozygous familial hypercholesterolaemia (HeFH) and understand current approaches to the identification and management of familial hypercholesterolaemia to inform future public health strategies. Methods: For this cross-sectional study, we assessed children and adolescents younger than 18 years with a clinical or genetic diagnosis of HeFH at the time of entry into the Familial Hypercholesterolaemia Studies Collaboration (FHSC) registry between Oct 1, 2015, and Jan 31, 2021. Data in the registry were collected from 55 regional or national registries in 48 countries. Diagnoses relying on self-reported history of familial hypercholesterolaemia and suspected secondary hypercholesterolaemia were excluded from the registry; people with untreated LDL cholesterol (LDL-C) of at least 13·0 mmol/L were excluded from this study. Data were assessed overall and by WHO region, World Bank country income status, age, diagnostic criteria, and index-case status. The main outcome of this study was to assess current identification and management of children and adolescents with familial hypercholesterolaemia. Findings: Of 63 093 individuals in the FHSC registry, 11 848 (18·8%) were children or adolescents younger than 18 years with HeFH and were included in this study; 5756 (50·2%) of 11 476 included individuals were female and 5720 (49·8%) were male. Sex data were missing for 372 (3·1%) of 11 848 individuals. Median age at registry entry was 9·6 years (IQR 5·8-13·2). 10 099 (89·9%) of 11 235 included individuals had a final genetically confirmed diagnosis of familial hypercholesterolaemia and 1136 (10·1%) had a clinical diagnosis. Genetically confirmed diagnosis data or clinical diagnosis data were missing for 613 (5·2%) of 11 848 individuals. Genetic diagnosis was more common in children and adolescents from high-income countries (9427 [92·4%] of 10 202) than in children and adolescents from non-high-income countries (199 [48·0%] of 415). 3414 (31·6%) of 10 804 children or adolescents were index cases. Familial-hypercholesterolaemia-related physical signs, cardiovascular risk factors, and cardiovascular disease were uncommon, but were more common in non-high-income countries. 7557 (72·4%) of 10 428 included children or adolescents were not taking lipid-lowering medication (LLM) and had a median LDL-C of 5·00 mmol/L (IQR 4·05-6·08). Compared with genetic diagnosis, the use of unadapted clinical criteria intended for use in adults and reliant on more extreme phenotypes could result in 50-75% of children and adolescents with familial hypercholesterolaemia not being identified. Interpretation: Clinical characteristics observed in adults with familial hypercholesterolaemia are uncommon in children and adolescents with familial hypercholesterolaemia, hence detection in this age group relies on measurement of LDL-C and genetic confirmation. Where genetic testing is unavailable, increased availability and use of LDL-C measurements in the first few years of life could help reduce the current gap between prevalence and detection, enabling increased use of combination LLM to reach recommended LDL-C targets early in life

The Voltage Collapse Problem Based On The Power System Loadability

This paper addresses the problem of voltage instability at which the power system reaches its maximum admissible load. A voltage collapse proximity indicator (VCPI) is derived and its performance is investigated. The VCPI is the ratio of the system equivalent impedance to the load equivalent impedance. In this paper, an algorithm for network equivalent impedance is proposed; it employs the PV-PQ sensitivity and "referencing" techniques to determine an equivalent impedance of a multi-machine multi-node power system. The validity and effectiveness of this method is demonstrated with the application of different network configurations ranging from the standard IEEE 14-bus to the realistic 116-bus Qatar power system

Voltage Stability Margin Identification Using Local Measurements And Linear Kalman Filter

Voltage stability investigation is of a great importance for long-term electric load expansion as well as power system operation. This paper presents a new algorithm for identification of voltage instability in a specified load bus in a power system. The proposed algorithm is based on the linear Kalman filtering algorithm and the maximum power transfer principle. The proposed technique is used to identify Thevenin's equivalent circuit at a bus for different loading conditions, either when the total system loads change at the same rate (long-term voltage stability problem) or when a load on a certain bus changes. The proposed algorithm uses the real measurements at the bus in question to calculate the load impedance. These measurements are the load voltage and current. Thus, it can be implemented on-line on the control centers to investigate the voltage stability. The proposed algorithm is implemented to the standard IEEE 30-bus system

Investigation into ultraviolet radiations from modern electric light sources

Due to concerns of increasing electrical energy demand and government regulations, traditional incandescent lamps are being replaced by energy-efficient lamps, such as compact fluorescent lamps (CFLs) and light emitting diodes (LEDs). The widespread adoption of new solid-state light sources requires investigation into several effects associated with these alternative light sources. One of the important concerns is ultraviolet (UV) radiations coming out of these new light sources. This brief report presents the experimental data obtained on UV radiations from CFLs and LEDs. 1 2016 Informa UK Limited, trading as Taylor & Francis Group.This publication was made possible by UREP [grant number15-075-2-027] from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Matrix converters for electric power conversion: Review of topologies and basic control techniques

A matrix converter (MC) is a topology for ac-ac power conversion that has been widely investigated and compared with conventional ac-dc-ac topologies because of its attractive features. The MC is formed of controlled active devices and does not include any sizeable passive components. The converter can be used to directly control single/three/multiphase loads. MCs are highly effective in controlling the power factor and providing sinusoidal input and output currents. This paper provides a comprehensive state of the art review of the MC and discusses the main topology variations including single-phase conventional and isolated MCs, three-phase direct and indirect MCs, impedance source (Z-source) MCs, multiphase MCs, and multilevel MCs (MMCs). The aim of this research article is to provide a one-stop information on single/three/multiphase matrix, Z-source matrix, and multilevel MCs for potential readers, researchers, and practicing engineers. - 2019 John Wiley & Sons, Ltd.This publication was made possible by QU High Impact grant QUHI-CENG-19/20-2 from the Qatar University. The statements made herein are solely the responsibility of the authors.Scopu

Online adaptation of rotor resistance based on sliding mode observer kwith backstepping control of a five-phase induction motor drives

Multiphase electric drives have been developed due to numerous advantages offered by those machines when it compared with the conventional three-phase machines. Multiphase motor drives are considered for applications, where the reduction of power per phase for both motor and inverter and high reliability are required. High performance control techniques are developed for multi-phase drives. The performances of the high performance controller and flux observers may be degraded during the operation. Since the parameters of Induction Motor (IM) varies continuously due to temperature variation and heating.Thus it is significantly important that the value of rotor resistance is continuously observed online and adapted by the control algorithm in order to avoid detuning effects. The efficiency and performance of an induction motor drive system can be improved by online observation of the critical parameters, such as the rotor resistance and stator resistance. Among the parameters of IM, rotor resistance is a decisive one for flux estimation, and also the stator resistance becomescritical in the low-speed operation condition. This paper presents a new online estimation method for the rotor resistance of the IM for sliding mode observer. This method generally based on theoriesof variable structure and is useful in order to adjust online unknown parameters (load torque and rotor resistance). The presented non-linear compensator afford a voltage inputs on the articulation of stator current and rotor speed measurements, and engender an estimates for the unknown parameters simultaneously, the non-measurable state variables (rotor flux and derivatives of the stator current and voltage) that converge to the corresponding true values. Under the persistent excitation condition, the proposed method estimates the actual value of rotor resistance, which guarantees the exact estimation of the rotor flux. Non-linear Backstepping control and adaptive sliding mode observer of a five-phase induction motor drive is presented. The accuracy and validity of the method is verified by MATLAB simulation model. 2016 Institute of Advanced Engineering and Science. All rights reserved.Scopu