102 research outputs found
Web cluster load balancing via genetic-fuzzy based algorithm
In this genetic-fuzzy based Generalized Dimension Exchange (GDE) method is proposed to uniformly distribute the unprecedented Web cluster workload. Fuzzy set theory is used to capture the vagueness of the workload during redistribution period. Fuzzy set theory is used to capture the vagueness of the workload during redistribution period. According to the experts’ subjective evaluations, a fuzzy inference system is established to aggregate the fuzzy web performance metrics into a so-called load-weight index which indicates the servers workload intensity. Based on the load-weight index, the genetic-fuzzy algorithm is applied to equally redistribute the workload among in the servers. Finally, a simulation of 20 load-weight indices in a topology of 3-cube form Web cluster is implemented to illustrate the functionality of the proposed method
The HARX-GJR-GARCH skewed-t multipower realized volatility modelling for S&P 500
The heterogeneous autoregressive (HAR) models are used in modeling high frequency multipower realized volatility of the S&P 500 index. Extended from the standard realized volatility, the multipower realized volatility representations have the advantage of handling the possible abrupt jumps by smoothing the consecutive volatility. In order to accommodate clustering volatility and asymmetric of multipower realized volatility, the HAR model is extended by the threshold autoregressive conditional heteroscedastic (GJR-GARCH) component. In addition, the innovations of the multipower realized volatility are characterized by the skewed student-t distributions. The extended model provides the best performing in-sample and out-of-sample forecast evaluations
An Improvement to LMSV Parameter Estimation: Modelling and Forecasting Volatility and Value-at-risk
This paper proposes an improvement to the long memory stochastic volatility (LMSV) model to forecast volatility using high frequency data. To allow frequency domain quasi-maximum likelihood (FDQML) estimation, we suggest a parsimonious normalization procedure that avoids repetitive parameter estimation. This resultantly produces more efficient parameter estimation as less estimation error is involved. Besides, a de-trending procedure is proposed prior to the de-seasonalization procedure to improve the identification of seasonal patterns. We compare the performance of volatility forecasts by the proposed refined FDQML-LMSV model with the existing LMSV and the linear long memory model that fits to logarithms of realised volatility. The empirical results show that the proposed method outperforms the existing models statistically, and the output of the proposed method improves the accuracy and efficiency in value-at-risk forecasting
The mediating role of work engagement in the relationship between executive functioning deficits and employee well-being
Executive functioning and its related components have been found to promote well-being. However, there is a limited understanding of the underlying mechanism. Drawing from the job demands–resources and PERMA models, the present study examined the hypothetical mediating role of work engagement in the relationship between executive functioning deficit and well-being among 314 working adults in Malaysia. Participants answered a survey consisting of the Executive Skills Questionnaire-Revised (ESQ-R; a new measure of executive functioning deficits for working adults), Utrecht Work Engagement Scale, Employee Well-Being Scale, and Self-Rated Creativity Scale. Pearson correlation analysis showed that the ESQ-R score was negatively associated with all other target variables, while the latter was positively related to each other. Moreover, supporting the hypotheses, the results of mediation analysis using PROCESS macro found that work engagement mediated the negative relationship between executive functioning deficits and well-being after statistically controlling for the creativity score. The findings not only replicate the beneficial role of executive functioning in employees’ well-being but also shed light on the underlying process of the relationship. Implications and directions for future studies are discussed
Improvement of gastroprotective and anti-ulcer effect of kenaf seed oil-in-water nanoemulsions in rats
Kenaf seed oil-in-water nanoemulsions (KSON) and kenaf seed oil-in-water macroemulsions were produced to access their gastroprotective effect against indomethacin- and ethanol-induced ulcers in comparison with non-emulsified kenaf seed oil (KSO). Emulsifier mixture (EM) that used to emulsify KSO was also included in the study. Ulcer index, stomach tissue oxidative status, and histopathological changes in indomethacin-induced and ethanol-induced ulcer models were both evaluated. KSON had demonstrated good gastroprotective effect against both ulcer models than non-emulsified KSO and KSOM. In addition, the gastroprotective effect of KSON was comparable to the standard drug, Omeprazole. EM also exhibited gastroprotective effect, especially in indomethacin-induced ulcers. This may be attributed to its high antioxidant activity and cytoprotective effect of sodium caseinate contained in the EM. Results supported that KSON enhanced the bioavailability of native KSO; therefore it offers gastroprotective effect for the prevention of gastric ulceration as a natural alternative to the synthetic drug
The perspectives of health professionals and patients on racism in healthcare: A qualitative systematic review
Objective:
To understand racial bias in clinical settings from the perspectives of minority patients and healthcare providers to inspire changes in the way healthcare providers interact with their patients.
Methods:
Articles on racial bias were searched on Medline, CINAHL, PsycINFO, Web of Science. Full text review and quality appraisal was conducted, before data was synthesized and analytically themed using the Thomas and Harden methodology.
Results:
23 articles were included, involving 1,006 participants. From minority patients’ perspectives, two themes were generated: 1) alienation of minorities due to racial supremacism and lack of empathy, resulting in inadequate medical treatment; 2) labelling of minority patients who were stereotyped as belonging to a lower socio-economic class and having negative behaviors. From providers’ perspectives, one theme recurred: the perpetuation of racial fault lines by providers. However, some patients and providers denied racism in the healthcare setting.
Conclusion:
Implicit racial bias is pervasive and manifests in patient-provider interactions, exacerbating health disparities in minorities. Beyond targeted anti-racism measures in healthcare settings, wider national measures to reduce housing, education and income inequality may mitigate racism in healthcare and improve minority patient care
A Systematic Scoping Review of Ethical Issues in Mentoring in Surgery.
Background:Mentoring is crucial to the growth and development of mentors, mentees, and host organisations. Yet, the process of mentoring in surgery is poorly understood and increasingly mired in ethical concerns that compromise the quality of mentorship and prevent mentors, mentees, and host organisations from maximising its full potential. A systematic scoping review was undertaken to map the ethical issues in surgical mentoring to enhance understanding, assessment, and guidance on ethical conduct. Methods:Arksey and O'Malley's methodological framework was used to guide a systematic scoping review involving articles published between January 1, 2000 and December 31, 2018 in PubMed, Embase, Scopus, ERIC, ScienceDirect, Mednar, and OpenGrey databases. Braun and Clarke's thematic analysis approach was adopted to compare ethical issues in surgical mentoring across different settings, mentee and mentor populations, and host organisations. Results:A total of 3849 abstracts were identified, 464 full-text articles were retrieved, and 50 articles were included. The 3 themes concerned ethical lapses at the levels of mentor or mentee, mentoring relationships, and host organisation. Conclusions:Mentoring abuse in surgery involves lapses in conduct, understanding of roles and responsibilities, poor alignment of expectations, and a lack of clear standards of practice. It is only with better structuring of mentoring processes and effective support of host organisation tasked with providing timely, longitudinal, and holistic assessment and oversight will surgical mentoring overcome prevailing ethical concerns surrounding it
Specific, sensitive and rapid detection of human plasmodium knowlesi infection by loop-mediated isothermal amplification (LAMP) in blood samples
<p>Abstract</p> <p>Background</p> <p>The emergence of <it>Plasmodium knowlesi </it>in humans, which is in many cases misdiagnosed by microscopy as <it>Plasmodium malariae </it>due to the morphological similarity has contributed to the needs of detection and differentiation of malaria parasites. At present, nested PCR targeted on <it>Plasmodium </it>ssrRNA genes has been described as the most sensitive and specific method for Plasmodium detection. However, this method is costly and requires trained personnel for its implementation. Loop-mediated isothermal amplification (LAMP), a novel nucleic acid amplification method was developed for the clinical detection of <it>P. knowlesi</it>. The sensitivity and specificity of LAMP was evaluated in comparison to the results obtained via microscopic examination and nested PCR.</p> <p>Methods</p> <p>LAMP assay was developed based on <it>P. knowlesi </it>genetic material targeting the apical membrane antigen-1 (AMA-1) gene. The method uses six primers that recognize eight regions of the target DNA and it amplifies DNA within an hour under isothermal conditions (65°C) in a water-bath.</p> <p>Results</p> <p>LAMP is highly sensitive with the detection limit as low as ten copies for AMA-1. LAMP detected malaria parasites in all confirm cases (n = 13) of <it>P. knowlesi </it>infection (sensitivity, 100%) and none of the negative samples (specificity, 100%) within an hour. LAMP demonstrated higher sensitivity compared to nested PCR by successfully detecting a sample with very low parasitaemia (< 0.01%).</p> <p>Conclusion</p> <p>With continuous efforts in the optimization of this assay, LAMP may provide a simple and reliable test for detecting <it>P. knowlesi </it>malaria parasites in areas where malaria is prevalent.</p
Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis
BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
Phenomic analysis of chronic granulomatous disease reveals more severe integumentary infections in X-Linked compared with autosomal recessive chronic granulomatous disease
BACKGROUND : Chronic granulomatous disease (CGD) is an inborn error of immunity (IEI),
characterised by recurrent bacterial and fungal infections. It is inherited either in an Xlinked (XL) or autosomal recessive (AR) mode. Phenome refers to the entire set of
phenotypes expressed, and its study allows us to generate new knowledge of the
disease. The objective of the study is to reveal the phenomic differences between XL
and AR-CGD by using Human Phenotype Ontology (HPO) terms. METHODS : We collected data on 117 patients with genetically diagnosed CGD from Asia
and Africa referred to the Asian Primary Immunodeficiency Network (APID network). Only
90 patients with sufficient clinical information were included for phenomic analysis. We
used HPO terms to describe all phenotypes manifested in the patients.
RESULTS : XL-CGD patients had a lower age of onset, referral, clinical diagnosis, and
genetic diagnosis compared with AR-CGD patients. The integument and central nervous
system were more frequently affected in XL-CGD patients. Regarding HPO terms, perianal
abscess, cutaneous abscess, and elevated hepatic transaminase were correlated with
XL-CGD. A higher percentage of XL-CGD patients presented with BCGitis/BCGosis as
their first manifestation. Among our CGD patients, lung was the most frequently infected
organ, with gastrointestinal system and skin ranking second and third, respectively.
Aspergillus species, Mycobacterium bovis, and Mycobacteirum tuberculosis were the
most frequent pathogens to be found.
CONCLUSION : Phenomic analysis confirmed that XL-CGD patients have more recurrent
and aggressive infections compared with AR-CGD patients. Various phenotypic
differences listed out can be used as clinical handles to distinguish XL or AR-CGD
based on clinical features.The Society for Relief of Disabled Children and Jeffrey Modell Foundation.https://www.frontiersin.org/journals/immunologydm2022Paediatrics and Child Healt
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