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The Incidence of Splenic Injury Following Blunt Abdominal Trauma (BAT), Sultan Qaboos University Hospital Experience
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作者 Abdullah Al-Busaidi Tariq Al-Shafei +4 位作者 Huda Al-Moqbali Sara Al-Kindi Mohammed Al-Saadi Nadya Al-Busaidi Hani Al-Qadhi 《Surgical Science》 2017年第7期312-318,共7页
The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. I... The aim of the study was to review traumatic splenic injury following blunt abdominal trauma (BAT), during the period from January 2009 to January 2015 at SQUH. The data for this study was retrospectively collected. It included 768 patients admitted to SQUH general surgery department following BAT. 43 patients with splenic injury were identified (34 males, 9 females). The mean age of patients with splenic injury was 36.0 years (34.4 years for males, 42.1 years for females). The most common mechanism of injury was motor vehicle collision (90.7%). Grade I, II are the most common grades of splenic injury. Non-Omani patients accounted for (51.2%) and most of them were pedestrians at the time of trauma. Ribs fracture is the most common injury associated with splenic injury. 36 (83.7%) patients were managed conservatively and 7 (16.3%) patients were splenectomized. Angioembolization was done for 11 (30.6%) patients. Despite the small population of Oman, high incidence of motor vehicle collision (MVC) increases the incidence of splenic injury among young age group. 展开更多
关键词 SPLEEN SPLENIC Injury BLUNT ABDOMINAL TRAUMA Motor Vehicle Collision
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Suppression and synchronization of chaos in uncertain time-delay physical system
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作者 Israr Ahmad Muhammad Shafiq 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2024年第3期416-437,共22页
The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous contr... The mechanical horizontal platform(MHP)system exhibits a rich chaotic behavior.The chaotic MHP system has applications in the earthquake and offshore industries.This article proposes a robust adaptive continuous control(RACC)algorithm.It investigates the control and synchronization of chaos in the uncertain MHP system with time-delay in the presence of unknown state-dependent and time-dependent disturbances.The closed-loop system contains most of the nonlinear terms that enhance the complexity of the dynamical system;it improves the efficiency of the closed-loop.The proposed RACC approach(a)accomplishes faster convergence of the perturbed state variables(synchronization errors)to the desired steady-state,(b)eradicates the effect of unknown state-dependent and time-dependent disturbances,and(c)suppresses undesirable chattering in the feedback control inputs.This paper describes a detailed closed-loop stability analysis based on the Lyapunov-Krasovskii functional theory and Lyapunov stability technique.It provides parameter adaptation laws that confirm the convergence of the uncertain parameters to some constant values.The computer simulation results endorse the theoretical findings and provide a comparative performance. 展开更多
关键词 chaotic horizontal platform system chaos suppression chaos synchronization robust adaptive control Lyapunov stability theory
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Modelling of debris-flow susceptibility and propagation: a case study from Northwest Himalaya
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作者 Hamza DAUD Javed Iqbal TANOLI +5 位作者 Sardar Muhammad ASIF Muhammad QASIM Muhammad ALI Junaid KHAN Zahid Imran BHATTI Ishtiaq Ahmad Khan JADOON 《Journal of Mountain Science》 SCIE CSCD 2024年第1期200-217,共18页
The geological and geographical position of the Northwest Himalayas makes it a vulnerable area for mass movements particularly landslides and debris flows. Mass movements have had a substantial impact on the study are... The geological and geographical position of the Northwest Himalayas makes it a vulnerable area for mass movements particularly landslides and debris flows. Mass movements have had a substantial impact on the study area which is extending along Karakorum Highway(KKH) from Besham to Chilas. Intense seismicity, deep gorges, steep terrain and extreme climatic events trigger multiple mountain hazards along the KKH, among which debris flow is recognized as the most destructive geohazard. This study aims to prepare a field-based debris flow inventory map at a regional scale along a 200 km stretch from Besham to Chilas. A total of 117 debris flows were identified in the field, and subsequently, a point-based debris-flow inventory and catchment delineation were performed through Arc GIS analysis. Regional scale debris flow susceptibility and propagation maps were prepared using Weighted Overlay Method(WOM) and Flow-R technique sequentially. Predisposing factors include slope, slope aspect, elevation, Topographic Roughness Index(TRI), Topographic Wetness Index(TWI), stream buffer, distance to faults, lithology rainfall, curvature, and collapsed material layer. The dataset was randomly divided into training data(75%) and validation data(25%). Results were validated through the Receiver Operator Characteristics(ROC) curve. Results show that Area Under the Curve(AUC) using WOM model is 79.2%. Flow-R propagation of debris flow shows that the 13.15%, 22.94%, and 63.91% areas are very high, high, and low susceptible to debris flow respectively. The propagation predicated by Flow-R validates the naturally occurring debris flow propagation as observed in the field surveys. The output of this research will provide valuable input to the decision makers for the site selection, designing of the prevention system, and for the protection of current infrastructure. 展开更多
关键词 North Pakistan Debris flow Flow-R Propagation Susceptibility mapping Debris-flow inventory Weighted Overlay Method
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Elevating Localization Accuracy in Wireless Sensor Networks:A Refined DV-Hop Approach
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作者 Muhammad Aamer Ejaz Kamalrulnizam Abu Bakar +4 位作者 Ismail Fauzi Bin Isnin Babangida Isyaku Taiseer Abdalla Elfadil Eisa Abdelzahir Abdelmaboud Asma Abbas Hassan Elnour 《Computers, Materials & Continua》 SCIE EI 2024年第10期1511-1528,共18页
Localization is crucial in wireless sensor networks for various applications,such as tracking objects in outdoor environments where GPS(Global Positioning System)or prior installed infrastructure is unavailable.Howeve... Localization is crucial in wireless sensor networks for various applications,such as tracking objects in outdoor environments where GPS(Global Positioning System)or prior installed infrastructure is unavailable.However,traditional techniques involve many anchor nodes,increasing costs and reducing accuracy.Existing solutions do not address the selection of appropriate anchor nodes and selecting localized nodes as assistant anchor nodes for the localization process,which is a critical element in the localization process.Furthermore,an inaccurate average hop distance significantly affects localization accuracy.We propose an improved DV-Hop algorithm based on anchor sets(AS-IDV-Hop)to improve the localization accuracy.Through simulation analysis,we validated that the ASIDV-Hop proposed algorithm is more efficient in minimizing localization errors than existing studies.The ASIDV-Hop algorithm provides an efficient and cost-effective solution for localization in Wireless Sensor Networks.By strategically selecting anchor and assistant anchor nodes and rectifying the average hop distance,AS-IDV-Hop demonstrated superior performance,achieving a mean accuracy of approximately 1.59,which represents about 25.44%,38.28%,and 73.00%improvement over other algorithms,respectively.The estimated localization error is approximately 0.345,highlighting AS-IDV-Hop’s effectiveness.This substantial reduction in localization error underscores the advantages of implementing AS-IDV-Hop,particularly in complex scenarios requiring precise node localization. 展开更多
关键词 LOCALIZATION anchor nodes COLLINEARITY CONNECTIVITY hop based
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Assessment of Appropriateness of Diagnostic Lymph Node Tissue Collection from the Operating Theater and by Interventional Radiologist. A Clinical Audit
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作者 Kowthar Salman Hassan Divya Deodhar +1 位作者 Abdullah T. Al-Rawahi Mahmood H. Al Abri 《Advances in Infectious Diseases》 CAS 2024年第3期541-548,共8页
Background: Appropriate sample requesting, collecting and timely dispatch to the appropriate laboratory is essential in establishing diagnosis of pathologies with lesions. Much time and effort may be wasted if this is... Background: Appropriate sample requesting, collecting and timely dispatch to the appropriate laboratory is essential in establishing diagnosis of pathologies with lesions. Much time and effort may be wasted if this is not done according to certain standards. We conducted this study to assess the route of lymph node samples from requests to reaching the laboratories. Methods: We conducted an audit over a period from 4th June until 10th Aug 2023. Data for all the procedures performed over this period on lymph node samples (was entered into and analysed using Excel. Results: A total of eighteen samples for sixteen patients were obtained during this period. Median age of the patients was 34 years (19 - 73) with a M:F ratio of 5:11. Among the IR samples, nine samples were from the neck, three from inguinal area and one from axilla. Seven samples (53.8%) were tru-cut biopsies, six samples (46.15%) were FNA. All samples were sent to the pathology laboratory fixed in formalin. Samples for TB were sent only for five cases (31.25%) and for only two cases (12.5%) were samples sent for bacterial culture. For the OR samples, none were sent for either bacterial culture or TB. Overall, eight patients (50%) were not investigated for any infectious etiologies like brucella, toxoplasmosis, CMV, EBV plus other possible causes. Repeat sampling was required for 25% of patients (within and out of the audit period). Conclusions: to avoid delays in making diagnoses, it is paramount to consider infectious etiologies as possible diagnosis for lymphadenopathy and request appropriate investigations. This requires liaising with infectious diseases/clinical microbiology experts to guide regarding types of samples, types of media and timely dispatch to the correct laboratory. 展开更多
关键词 Clinical Audit Clinical Samples BIOPSIES Lymph Nodes Saline FORMALIN Quality Improvement
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Assistive techniques and their added value for tremor classification in multiple sclerosis
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作者 Nabin Koirala Abdulnasir Hossen +2 位作者 Ioannis U.Isaias Jens Volkmann Muthuraman Muthuraman 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第5期977-978,共2页
Tremor occurs in about half of multiple sclerosis(MS)patients.MS tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tre... Tremor occurs in about half of multiple sclerosis(MS)patients.MS tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tremor may affect the upper and lower extremities,head,and trunk,and may even affect the vocal cords in isolated cases of palatal tremor.MS tremor is classically attributed to lesions of the brain stem,cerebellum,or cerebellar peduncles,and tremor intensity has been shown to correlate with the number of lesions or their functional connections.However,recent work has demonstrated that inflammatory damage to the cerebello-thalamic and cortico-thalamic pathways might also play an important role in causing tremor,as it co-occurs with other signs and symptoms of MS such as dysarthria,dysmetria,dysdiadochokinesia,and dystonia(Alusi et al.,2001). 展开更多
关键词 TREMOR SCLEROSIS
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Toxicity Evaluation of Different Exposure Scenarios of Road Dust Using Daphnia magna and Artemia salina as Aquatic Organisms, and Prosopis cineraria and Vachellia tortilis as Native Plant Species
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作者 Hilal K. Al-Shidi Hameed Sulaiman 《Open Journal of Air Pollution》 2024年第3期73-86,共14页
Particulate matter (PM10) deposited as road dust is considered an important source of contamination from atmosphere. However, there are limited studies on the toxicity of road dust as such on different organisms. This... Particulate matter (PM10) deposited as road dust is considered an important source of contamination from atmosphere. However, there are limited studies on the toxicity of road dust as such on different organisms. This study evaluates the toxicity of road dust using different extraction scenarios on Daphnia magna and Artemia salina as aquatic organisms and also on Prosopis cineraria and Vachellia tortilis as local plant species. Chemical analysis of different extracts shows considerable amount of trace metals, however the trace metals in the dust extract associated with suspended sediment were not absorbed by the receptors. On the other hand, the concentration of trace metals in the artificial mixture was found bioavailable and absorbed causing a high percentage of mortality. In the plant assay, significant difference was obtained in the germination percentage between the control and three different extraction exposures in both plant species. The mean root length of P. cineraria and V. tortilis were higher in 20% and 50% extracts than the control probably due to the availability of nutrients from the dust extract. Interestingly however, the seedling vigor index was the opposite with higher index in the control and lower in dust extracts that contain heavy metals. 展开更多
关键词 Road Dust Heavy Metals TOXICITY BIOAVAILABILITY Holding Time
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Evaluating pediatric ureteropelvic junction obstruction:Dynamic magnetic resonance urography vs renal scintigraphy 99mtechnetium mercaptoacetyltriglycine
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作者 Yousuf Al-Shaqsi Matthieu Peycelon +4 位作者 Annabel Paye-Jaouen Elisabeth Carricaburu Anca Tanase Christine Grapin-Dagorno Alaa El-Ghoneimi 《World Journal of Radiology》 2024年第3期49-57,共9页
BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to sympt... BACKGROUND Ureteropelvic junction obstruction(UPJO)is a common congenital urinary tract disorder in children.It can be diagnosed as early as in utero due to the presence of hydronephrosis or later in life due to symptomatic occurrence.AIM To evaluate the discrepancy between dynamic contrast-enhanced magnetic resonance urography(dMRU)and scintigraphy 99m-technetium mercaptoacetyltriglycine(MAG-3)for the functional evaluation of UPJO.METHODS Between 2016 and 2020,126 patients with UPJO underwent surgery at Robert DebréHospital.Of these,83 received a prenatal diagnosis,and 43 were diagnosed during childhood.Four of the 126 patients underwent surgery based on the clinical situation and postnatal ultrasound findings without undergoing functional imaging evaluation.Split renal function was evaluated preoperatively using scintigraphy MAG-3(n=28),dMRU(n=53),or both(n=40).In this study,we included patients who underwent surgery for UPJO and scintigraphy MAG-3+dMRU but excluded those who underwent only scintigraphy MAG-3 or dMRU.The patients were divided into groups A(<10%discrepancy)and B(>10%discrepancy).We examined the discrepancy in split renal function between the two modalities and investigated the possible risk factors.RESULTS The split renal function between the two kidneys was compared in 40 patients(28 boys and 12 girls)using scintigraphy MAG-3 and dMRU.Differential renal function,as determined using both modalities,showed a difference of<10%in 31 children and>10%in 9 children.Calculation of the relative renal function using dMRU revealed an excellent correlation coefficient with renal scintigraphy MAG-3 for both kidneys.CONCLUSION Our findings demonstrated that dMRU is equivalent to scintigraphy MAG-3 for evaluating split renal function in patients with UPJO. 展开更多
关键词 Uteropelvic junction obstruction Scintigraphy 99m-technetium mercaptoacetyltriglycine Magnetic resonance imaging Dynamic contrast-enhanced magnetic resonance urography
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Chemical composition of essential oils and in vitro antioxidant activity of fresh and dry leaves crude extracts of medicinal plant of Lactuca Sativa L.native to sultanate of Oman 被引量:3
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作者 Rahma Said Salim Al Nomaani Mohammad Amzad Hossain +2 位作者 Afaf Mohammed Weli Qasim Al-Riyami Jamal Nasser Al-Sabahi 《Asian Pacific Journal of Tropical Biomedicine》 SCIE CAS 2013年第5期353-357,共5页
Objective:To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L.(L... Objective:To isolate and analyse the chemical composition in the essential oils and free radical scavenging activity of different crude extracts from the fresh and dry leaves of vegetable plants of Lactuca sativa L.(L.sativa).Methods:The essential oils and volatile chemical constituents were isolated from the fresh and dry leaves of L.sativa(lettuce)grown in Sultanate of Oman by hydro distillation method.The antioxidant activity of the crude extracts was carried out by well established free radical scavenging activity(DPPH)method.Results:About 20 chemical compounds of different concentration representing 83.07%and 79.88%respectively were isolated and identified by gas chromatography-mass spectroscopy in the essential oils isolated from the fresh and dry leaves asα-pinene(5.11%and 4.05%).γ-cymene(2.07%and 1.92%),thymol(11.55%and 10.73%),durenol(52.00%and 49.79%),α-terpinene(1.66%and 1.34%),thymol acetate(0.99%and 0.67%),caryophyllene(2.11%and 1.98%),spathulenol(3.09%and 2.98%).camphene(4.11%and3.65%),limonene(1.28%and 1.11%)representing these major chemical compounds.However,some other minor chemical constituents were also isolated and identified from the essential oil of lettuce including p-pinene,α-terpinolene,linalool,4-terpineol,α-terpineol,o-methylthymol,L-alloaromadendrene and viridiflorene.Conclusions:The chemical consliluents in the essential oils from the locally grown lettuce were identified in the following classes or groups of chemical compounds such as monoterpenes,sesquiterpenes volatile organic compounds and their oxygenated hydrocarbons.Therefore,the essential oils and the crude extracts from Omani vegetable species of lettuce are active candidates which would be used as antioxidant,antifungal or antimicrobial agents in new drugs preparation for therapy of infectious diseases. 展开更多
关键词 LACTUCA SALIVA Omani LETTUCE Clevenger apparatus Essential oil Durenol THYMOL SOXHLET extractor Organic crude extracts Antioxidant activity GC-MS analyses
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Application of Geo-Processing Model for a Quantitative Assessment of Coastal Exposure and Sensitivity to Sea Level Rise in the Sultanate of Oman
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作者 Salim Al-Hatrushi Elnazir Ramadan Yassine Charabi 《American Journal of Climate Change》 2015年第4期379-384,共6页
The Sultanate of Oman has a long coastline extending for about 3165 km including a number of bays and islands. Oman’s coastline borders the Arabian Gulf, the Sea of Oman and the Arabian Sea. Most of this coastline is... The Sultanate of Oman has a long coastline extending for about 3165 km including a number of bays and islands. Oman’s coastline borders the Arabian Gulf, the Sea of Oman and the Arabian Sea. Most of this coastline is soft and low laying shore subject to the dynamics of sediment transport and the landward retreat of the shoreline, caused by anthropogenic factors and sea level rise associated with climate change. This paper aims to assess the vulnerability of the entire Omani coastal zone to the expected sea level rise and storm surge. Methodology is based on applying Coastal Vulnerability Index (CVI) to identify clusters of high vulnerability areas according to their sensitivity and dynamic nature and increased risk resulted from seal level rise, erosion and extreme weather events. The coastal line of the governorates of Al Batinah, Muscat and Al-Wusta has scored highly due to possessing similar physical attributes. Based on that assessment a coastal vulnerability database utilizing GIS was created to help stakeholders involved in the coastal management to make better decisions. 展开更多
关键词 SEA Level RISE CVI COASTAL VULNERABILITY Sultanate of Oman
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Spatial Assessment of Water Quantity Stress in Sultanate of Oman Provinces: A GIS Based Analysis of Water Resources Variability
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作者 Talal Al-Awadhi Shawky Mansour 《Journal of Geographic Information System》 2015年第6期565-578,共14页
Water quantity planning and management require understanding of spatial variations of water catchment availability. Several environmental indicators are associated with water quantity such as flood occurrence, drought... Water quantity planning and management require understanding of spatial variations of water catchment availability. Several environmental indicators are associated with water quantity such as flood occurrence, drought severity, seasonal supply and groundwater stress. Analyzing water stress at national geographic scale is crucial to detect and explore geographic shortage of water resources at national scale. In this study, Geographical Information Systems (GIS) techniques were employed to analyze the spatial variations of water scarcity across Sultanate of Oman provinces. For this main objective, various spatial and attribute datasets were prepared. Many variables were selected based on their importance and correlation with water quantity. GIS overlay function then was used to produce maps for each water indicator. This was followed by employing raster zonal statistics to aggregate the values of each catchment area within each province. The findings of this analysis indicated that significant spatial variation was found among Omani provinces in terms of water quantity stress and its determinants. The most important factors affecting the water quantity stress were drought severity and flood occurrence. Furthermore, physical risk of water quantity was higher in Mascut and Dhofar provinces while it was moderate in Al-Batinah, A’Dakhiliyah and Al-Wusta. Lower risk of water quantity was observed in A’Sharqiyah, Masandam, and A’Dhahriah provinces. Thus, in order to mitigate the impacts of water scarcity on agriculture, cultivation and domestic usages, policy makers in water sector should include spatial strategies for water resource maintain and allocation. 展开更多
关键词 GIS SPATIAL ASSESSMENT Water Quantity Omani PROVINCES
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Profile of Inpatient Child and Adolescent Psychiatry in Sultanate of Oman
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作者 Ahmed Bait Amer Rahab Al Aamri Intisar Al-Ruhaili 《Open Journal of Nursing》 2019年第4期449-457,共9页
Backgrounds: Mental illness is a common phenomenon at all ages. Various independent studies have shown that psychopathology is often expressed on a continuum from youth to adulthood. The aim of our study was to answer... Backgrounds: Mental illness is a common phenomenon at all ages. Various independent studies have shown that psychopathology is often expressed on a continuum from youth to adulthood. The aim of our study was to answer the question what are the problems that are likely to bring a child or an adolescent for the admission in the child and adolescent psychiatry Unit. Methods: The case records of all inpatient children and adolescents younger than 18 years, who were admitted to the child psychiatric unit at SQUH, Muscat, Sultanate of Oman over a period of 10 years between Jan 2007 and Dec 2017, were retrospectively reviewed in regard to sociodemographic data, referring specialties and reason for referral. Result: A total of 255 cases were admitted in child psychiatry unit in a period of 10 yrs, the average age was 14.15 years, 95% patients were Omani nationals, 47.5% were male, 52.5 were females, 17.65% Acute and transient psychotic disorder, 13.7% bipolar affective disorder, current episode manic without psychotic symptoms, 12.94% Intentional self-harm by other specified means and 12.55% schizophrenia, were the most common diagnoses observed in this population who needed inpatient care;the average length of stay in the majority of cases was less than 3 weeks. Conclusion: The child and adolescent inpatient unit of SQUH from where the data was collected happens to be the only child psychiatric admitting unit in Oman till the end of 2017 and can be considered as representative;the children and adolescence in-patient unit exemplifies a short-term care set-up. 展开更多
关键词 INPATIENT CHILD ADOLESCENT
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Stakeholders’ Views on Management Arrangements: A Case of Kingfish Fishery in the Sultanate of Oman
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作者 Abdullah Hilal Al-Balushi Shekar Bose Anesh Govender 《Natural Resources》 2016年第5期251-264,共14页
This paper exemplifies a primary step towards eliciting primary and secondary stakeholders’ views on management issues pertaining to kingfish fishery in Oman, and potential options for effective management of the fis... This paper exemplifies a primary step towards eliciting primary and secondary stakeholders’ views on management issues pertaining to kingfish fishery in Oman, and potential options for effective management of the fishery using questionnaire surveys and focus group interviews. There was consensus from stakeholder groups which included fishers, fishery managers, and fishery scientists that the current stock condition is not biologically sustainable. It is found that fishing effort control and technical measures are preferred to catch control by both groups. The role of mass media and the traditional institution in communicating fisheries issues are found to be relatively minor. Although the overall rating on the comprehensiveness of the proposed plan is promising, there are significant differences between the two groups with regard to legislative arrangements (χ<sup>2</sup> = 24.793, p-value = 0.000), management goals (χ<sup>2</sup> = 16.206, p-value = 0.001), operational objectives (χ<sup>2</sup> = 19.884, p-value = 0.000), performance indicators (χ<sup>2</sup> = 15.524, p-value = 0.001), and measures (χ<sup>2</sup> = 13.483, p-value = 0.004). Policy implications of the key findings are discussed in both national and regional contexts. Management authorities can use these findings to design an appropriate plan of actions for achieving sustainability in this fishery. 展开更多
关键词 Sustainability Kingfish Fishery Stakeholder Views Management Arrangements Oman
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TRUSED:A Trust-Based Security Evaluation Scheme for A Distributed Control System
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作者 Saqib Ali Raja Waseem Anwar 《Computers, Materials & Continua》 SCIE EI 2023年第2期4381-4398,共18页
Distributed control systems(DCS)have revolutionized the communication process and attracted more interest due to their pervasive computing nature(cyber/physical),their monitoring capabilities and the benefits they off... Distributed control systems(DCS)have revolutionized the communication process and attracted more interest due to their pervasive computing nature(cyber/physical),their monitoring capabilities and the benefits they offer.However,due to distributed communication,flexible network topologies and lack of central control,the traditional security strategies are inadequate formeeting the unique characteristics ofDCS.Moreover,malicious and untrustworthy nodes pose a significant threat during the formation of a DCS network.Trust-based secure systems not only monitor and track the behavior of the nodes but also enhance the security by identifying and isolating the malicious node,which reduces the risk and increases network lifetime.In this research,we offer TRUSED,a trust-based security evaluation scheme that both,directly and indirectly,estimates each node’s level of trustworthiness,incorporating the cumulative trust concept.In addition,simulation results show that the proposed technique can effectively identify malicious nodes,determine their node’s trustworthiness rating,and improve the packet delivery ratio. 展开更多
关键词 MALICIOUS network lifetime risk management SECURITY TRUST untrustworthy
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Extreme dependencies and spillovers between gold and stock markets:evidence from MENA countries
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作者 Walid Mensi Debasish Maitra +1 位作者 Refk Selmi Xuan Vinh Vo 《Financial Innovation》 2023年第1期1449-1475,共27页
This study addresses whether gold exhibits the function of a hedge or safe haven as often referred to in academia.It contributes to the existing literature by(i)revisiting this question for the principal stock markets... This study addresses whether gold exhibits the function of a hedge or safe haven as often referred to in academia.It contributes to the existing literature by(i)revisiting this question for the principal stock markets in the Middle East and North Africa(MENA)region and(ii)using the copula-quantile-on-quantile and conditional value at risk methods to detail the risks facing market participants provided with accurate information about various gold and stock market scenarios(i.e.,bear,normal,bull).The results provide strong evidence of quantile dependence between gold and stock returns.Positive correlations are found between MENA gold and stock markets when both are bullish.Conversely,when stock returns are bearish,gold markets show negative correlations with MENA stock markets.The risk spillover from gold to stock markets intensified during the global financial and European crises.Given the risk spillover between gold and stock markets,investors in MENA markets should be careful when considering gold as a safe haven because its effectiveness as a hedge is not the same in all MENA stock markets.Investors and portfolio managers should rebalance their portfolio compositions under various gold and stock market conditions.Overall,such precise insights about the heterogeneous linkages and spillovers between gold and MENA stock returns provide potential input for developing effective hedging strategies and optimal portfolio allocations. 展开更多
关键词 Copula CoVaR Extreme dependence GOLD MENA markets Risk spillovers
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Tail spillover effects between cryptocurrencies and uncertainty in the gold,oil,and stock markets
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作者 Walid Mensi Mariya Gubareva +2 位作者 Hee‑Un Ko Xuan Vinh Vo Sang Hoon Kang 《Financial Innovation》 2023年第1期2339-2365,共27页
This study investigates tail dependence among five major cryptocurrencies,namely Bitcoin,Ethereum,Litecoin,Ripple,and Bitcoin Cash,and uncertainties in the gold,oil,and equity markets.Using the cross-quantilogram meth... This study investigates tail dependence among five major cryptocurrencies,namely Bitcoin,Ethereum,Litecoin,Ripple,and Bitcoin Cash,and uncertainties in the gold,oil,and equity markets.Using the cross-quantilogram method and quantile connectedness approach,we identify cross-quantile interdependence between the analyzed variables.Our results show that the spillover between cryptocurrencies and volatility indices for the major traditional markets varies substantially across quantiles,implying that diversification benefits for these assets may differ widely across normal and extreme market conditions.Under normal market conditions,the total connectedness index is moderate and falls below the elevated values observed under bearish and bullish market conditions.Moreover,we show that under all market conditions,cryptocurrencies have a leadership influence over the volatility indices.Our results have important policy implications for enhancing financial stability and deliver valuable insights for deploying volatility-based financial instruments that can potentially provide cryptocurrency investors with suitable hedges,as we show that cryptocurrency and volatility markets are insignificantly(weakly)connected under normal(extreme)market conditions. 展开更多
关键词 Cryptocurrency Uncertainty indices Quantile spillover Crossquantilogram
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A decline in snow cover area of Passu and Ghulkin valleys between 1995 and 2022
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作者 Imran HUSSAIN Mumtaz ALI +6 位作者 Sher MUHAMMAD Wajid HASSAN Salar ALI Zakir HUSSAIN Syed Hammad ALI Shaukat ALI Muhammad Younis KHAN 《Journal of Mountain Science》 SCIE CSCD 2023年第12期3542-3551,共10页
The global cryosphere is experiencing accelerated melting due to climate change.Currently,the Karakoram anomaly is under discussion with a debate about the possibility that the anomaly may have recently ended.This stu... The global cryosphere is experiencing accelerated melting due to climate change.Currently,the Karakoram anomaly is under discussion with a debate about the possibility that the anomaly may have recently ended.This study aims to evaluate the up-to-date changes in snow cover in the western Karakoram region.We observed the snow cover changes in Passu and Ghulkin valleys in the Hunza River basin(HRB)of the Karakoram through multitemporal Landsat satellite data between 1995 and 2022.We found a significant reduction in snow cover in these valleys,with an average reduction rate of 0.42 km~2/yr,resulting in a total reduction of~11.46 km~2 between 1995 and 2022.This reduction in snow cover is consistent with the mass loss of glaciers in the Karakoram region in recent years.The decline in snow cover in these valleys is also consistent with the meteorological data.The temperature in summer(June)has significantly increased whereas the precipitation in the accumulation season(March)has decreased.These rapid changes suggest that it is crucially important to monitor the snow cover on a regular basis to support downstream management of snowmelt runoff.In addition,there is a need of planning for mitigation and adaptation strategies for snow-related hazards. 展开更多
关键词 CRYOSPHERE Snow covers area Climate change KARAKORAM
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Screening Tree Species for Carbon Storage Potential through Urban Tree Inventory in Planted Vegetation
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作者 Abdullah Sulaiman Al-Nadabi Hameed Sulaiman 《Open Journal of Forestry》 2023年第1期61-74,共14页
Urban tree inventory is a great tool for gathering data that can be used by different end users. This study attempted to chart the species diversity in planted areas and measure their tree diameter at breast height to... Urban tree inventory is a great tool for gathering data that can be used by different end users. This study attempted to chart the species diversity in planted areas and measure their tree diameter at breast height to screen them for the carbon storage potential. A total of 2860 trees belonging to 36 species were recorded in the planted vegetation in parks and avenue plantation. The dominant species were Azadirachta indicia (25.5%), Conocarpus erectus (19.2%), Ficus spp. (15.5%), Tabebuia rosea (9.2%), Peitophorum pterocarpum (9.0%) and the remaining represents (21.6%) of the tree identified in this study. It was found that the highest contribution of carbon sequestration (CO<sub>2</sub> equivalent) is dominated by the Ficus spp. (30.3%) with a total of 3399.3 tCO<sub>2</sub>eq, followed by Azadirachta indicia (25.4%) with a total of 2845.2 tCO<sub>2</sub>eq and Conocarpus erectus (20.4%) with a total of 2286 tCO<sub>2</sub>eq. The entire area has the capability to sequester around 11,213.3 tCO<sub>2</sub>eq and on average of 3.9 ± 0.1 tCO<sub>2</sub>eq. In accordance with the findings, it is imperative for the preservation of a sustainable environment to have vegetation that has the capacity to store carbon. The study suggests, there is potential to increase carbon sequestration in urban cities through plantation programs on existing and new land uses and along roads. 展开更多
关键词 Tree Inventory Urban Vegetation Carbon Storage Carbon Sequestration SCREENING
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Developing Low Temperature Glazes for Omani Clay Artworks: Laboratory Investigation to Reduce Costs by Using Frits
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作者 Badar Almamari Najlaa Alsaadi Qais Alsalhi 《New Journal of Glass and Ceramics》 CAS 2023年第2期17-34,共18页
The role of using frits in developing glazes for ceramics has increasingly received attention across a number of industrial ceramics fields in recent years. Over the past decade, the link between using frits for devel... The role of using frits in developing glazes for ceramics has increasingly received attention across a number of industrial ceramics fields in recent years. Over the past decade, the link between using frits for developing ceramics glazes and the reduction of financial costs has been at the center of much attention. Determining the impact of using frits in the local ceramics industry in Oman is important for the future study of this creative field. Using imported ready-made glazes, despite their long commercial success, is associated with a number of problems, including a shortage of suppliers, high costs, and logistical difficulties. Consequently, there is an urgent need to address the importance of developing glazes locally to help establish some workable solutions for the aforementioned problems. To date, no research studies have investigated using local Omani earthenware clays to make glazes by combining them with commercial frits using empirical laboratory methodologies. By developing low temperature chemical glaze recipes, the main aim of this study is to explore the possibilities of using Omani earthenware clays (OECs) and frits to create glazes that are suitable for local Omani ceramic works. 展开更多
关键词 Omani Earthenware Clays CERAMICS Frits
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Exploring Work-Related Stress and Coping Strategies among Omani Nurses Working in Tertiary Governmental Hospitals at Muscat: A Cross-Sectional Study
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作者 Safiya Al-Yaqoubi 《Open Journal of Nursing》 2023年第6期368-385,共18页
Introduction: Work-related stress has become a global issue in the nursing workplace, with about 9.20% - 68.0% of nurses globally experiencing stress. Conversely, work-related stress ranges between 20% and 40% in nurs... Introduction: Work-related stress has become a global issue in the nursing workplace, with about 9.20% - 68.0% of nurses globally experiencing stress. Conversely, work-related stress ranges between 20% and 40% in nursing. Other researchers noted that 35.1% of nurses globally experienced elevated stress levels. Stress can damage well-being and lead to coping, which can, directly and indirectly, improve well-being through a perceived state. Nurses need coping mechanisms to manage their stress levels and maintain stability. Coping mechanisms can vary greatly depending on a nurse’s culture and background. Numerous findings indicate that managing stress is more critical than the cause of stress and that the more successful a stress-management approach, the less damage stress brings. Objective: In response to this, it is necessary to explore Omani nurses’ stress level and their coping strategies working in tertiary governmental hospitals in Muscat. Methods: The sample size for this study was 383 Omani nurses, with a 100% response rate. This study used a descriptive cross-sectional design from 15 October 2020 to 30 November 2020. Samples were selected through proportionate population sampling (PPS) from the five selected tertiary hospitals. Data were collected by self-administered questionnaires using a perceived stress scale and Ways of Coping. A simple random sample within a stratum (each hospital admitting ward) was done to identify the study participants. The sample size for this study was 383 Omani nurses, with a 100% response rate. Results: About 83.3% of participants had a moderate perceived level of stress with an overall mean perceived stress level of 18.46 ± 4.52. The most common sources of perceived stress are feeling nervous and “stressed” in the last month (2.30 ± 0.95). According to the ways of coping strategies, nurses seemed to be resorting to more “planful problem” (mean = 11.04) and least was seeking social support (mean = 9.67). Conclusion: This study highlighted the work-related stress level of staff nurses, explored their ways of coping and determined the relationship between work-related stress levels and methods of coping. The key finding of this study was that the frequency of stress reported by nurses was high enough to suggest that their stress levels were significant, given the demanding nature of their profession that requires maximum attention. Additionally, nurses seemed to resort to more planful problem-solving mechanisms to deal with their stressful situations than other coping strategies. 展开更多
关键词 Stress Level Work-Related Stress Coping Strategies
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