Smart grids have become one of the important and challenging topics due to the numerous benefits it can bring to the power system. In this context, distributed generation (DG) is expected to play a ...significant role. The smart grid can have multiple configurations depending on the smart grid operating strategy and system conditions. In smart grids, DG could be operated either grid connected or islanded. Such flexible and variable configuration results in variable fault current levels which could impact the operation of the existing protective devices on the distribution system. In this paper, it is proposed to optimally size thyristor-controlled impedance (TCI) of both inductive and capacitive type to manage the fault current levels under different smart grid configurations. The salient benefit is to avoid damage and delayed operation of protective devices due to the variability in fault currents with synchronous-based DG. The problem is formulated as a nonlinear programming (NLP) problem and the optimum size and type of the TCI is determined using particle swarm optimization (PSO). Results show that by optimally locating and sizing TCI, fault current levels under various smart grid configurations can be managed and thus avoiding protective device coordination failure and damage.
A new numerical multiphase model is presented to study wave propagation over arbitrary shaped submerged obstacles. The high order space accurate weighted essentially non-oscillatory (WENO) method is ...adopted along with relatively coarse Cartesian uniform grids. Viscosity effects are included and the free surface is tracked using the level set method. The model is validated via application to solitary and progressive wave motion over rectangular, trapezoidal and semicircular obstacles. The complex flow field features induced near a large sized obstacle, including separation vortices and large free surface deformations, are accurately reproduced. Compared to other relatively complicated models, the present model is efficient and produces enhanced results.
Background and purpose
Well‐structured hallucinations in Parkinson’s disease (PD) are associated with poor prognosis and dementia. However, the predictive value of minor psychotic phenomena in ...cognitive deterioration is not well known. Cross‐sectional studies have shown that PD patients with minor hallucinations have more severe cortical atrophy than non‐hallucinators, but baseline and longitudinal studies addressing the evolution of these brain differences are lacking. The impact of developing minor hallucinations on cognitive impairment and cortical atrophy progression in early PD was explored.
Methods
One hundred and thirty‐one de novo PD patients from the Parkinson's Progression Marker Initiative for whom brain magnetic resonance imaging scans were available were included. Cognitive outcome at 5 years was compared between patients with and without minor hallucinations during follow‐up. Additionally, using gray matter volume (GMV) voxel‐based morphometry, cross‐sectional (at baseline) and longitudinal (1‐ and 2‐year GMV loss) structural brain differences between groups were studied.
Results
During follow‐up, 35.1% of patients developed minor hallucinations. At 5 years, these patients showed an increased prevalence of subjective cognitive decline compared to non‐hallucinators (44.1% vs. 13.9%; p < 0.001), but not formal cognitive impairment. Additionally, compared to non‐hallucinators, they exhibited reduced GMV at baseline in visuoperceptive areas and increased GMV loss in left temporal areas (p < 0.05 corrected).
Conclusions
Minor hallucinations seem to be an early clinical marker of increased neurodegeneration and are associated with mid‐term subjective cognitive decline. Longer follow‐up analyses would be needed to further define if these findings could reflect a higher risk of future cognitive deterioration.
Newly diagnosed Parkinson’s disease patients who develop minor hallucinations during the first 5 years of disease exhibit more extensive GMV loss at baseline and an increased rate of atrophy in the first years after diagnosis. These patients also showed an increased prevalence of subjective cognitive decline. Longer follow‐up analyses would be needed to further define if these findings could reflect a higher risk of future cognitive deterioration.
Limited data exist on viral hepatitis among migrant populations. This study investigated the prevalence of current hepatitis B virus (HBV) infection and lifetime hepatitis C virus (HCV) infection ...among Qatar's migrant craft and manual workers (CMWs), constituting 60% of the country's population. Sera collected during a nationwide COVID-19 population-based cross-sectional survey on CMWs between July 26 and September 9, 2020, underwent testing for HBsAg and HCV antibodies. Reactive samples underwent confirmatory testing, and logistic regression analyses were employed to explore associations with HBV and HCV infections. Among 2528 specimens tested for HBV infection, 15 were reactive, with 8 subsequently confirmed positive. Three samples lacked sufficient sera for confirmatory testing but were included in the analysis through multiple imputations. Prevalence of current HBV infection was 0.4% (95% CI 0.2-0.7%). Educational attainment and occupation were significantly associated with current HBV infection. For HCV infection, out of 2607 specimens tested, 46 were reactive, and 23 were subsequently confirmed positive. Prevalence of lifetime HCV infection was 0.8% (95% CI 0.5-1.2%). Egyptians exhibited the highest prevalence at 6.5% (95% CI 3.1-13.1%), followed by Pakistanis at 3.1% (95% CI 1.1-8.0%). Nationality, geographic location, and occupation were significantly associated with lifetime HCV infection. HBV infection is relatively low among CMWs, while HCV infection falls within the intermediate range, both compared to global and regional levels.
Limited data exists on herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) infections in migrant populations. This study investigated HSV-1 and HSV-2 seroprevalences and associations among craft ...and manual workers (CMWs) in Qatar who constitute 60% of Qatar's population. A national population-based cross-sectional seroprevalence survey was conducted on the CMW population, all men, between July 26 and September 9, 2020. 2,612 sera were tested for anti-HSV-1 IgG antibodies using HerpeSelect 1 ELISA IgG kits and for anti-HSV-2 IgG antibodies using HerpeSelect 2 ELISA IgG kits (Focus Diagnostics, USA). Univariable and multivariable logistic regression analyses were conducted to identify associations with HSV-1 and HSV-2 infections. Serological testing identified 2,171 sera as positive, 403 as negative, and 38 as equivocal for HSV-1 antibodies, and 300 sera as positive, 2,250 as negative, and 62 as equivocal for HSV-2 antibodies. HSV-1 and HSV-2 seroprevalences among CMWs were estimated at 84.2% (95% CI 82.8-85.6%) and 11.4% (95% CI 10.1-12.6%), respectively. HSV-1 infection was associated with nationality, educational attainment, and occupation. HSV-2 infection was associated with age, nationality, and educational attainment. Over 80% of CMWs are infected with HSV-1 and over 10% are infected with HSV-2. The findings highlight the need for sexual health programs to tackle sexually transmitted infections among the CMW population.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Background
Qatar experienced a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemic that disproportionately affected the craft and manual worker (CMW) population, who ...comprise 60% of the total population. This study aimed to assess ever and/or current infection prevalence in this population.
Methods
A cross-sectional population-based survey was conducted during July 26 to September 09, 2020, to assess both anti-SARS-CoV-2 positivity through serological testing and current infection positivity through polymerase chain reaction (PCR) testing. Associations with antibody and PCR positivity were identified through regression analyses.
Results
The study included 2641 participants, 69.3% of whom were <40 years of age. Anti-SARS-CoV-2 positivity was 55.3% (95% CI, 53.3%–57.3%) and was significantly associated with nationality, geographic location, educational attainment, occupation, and previous infection diagnosis. PCR positivity was 11.3% (95% CI, 9.9%–12.8%) and was significantly associated with nationality, geographic location, occupation, contact with an infected person, and reporting 2 or more symptoms. Infection positivity (antibody and/or PCR positive) was 60.6% (95% CI, 58.6%–62.5%). The proportion of antibody-positive CMWs who had a prior SARS-CoV-2 diagnosis was 9.3% (95% CI, 7.9%–11.0%). Only seven infections were ever severe, and only 1 was ever critical—an infection severity rate of 0.5% (95% CI, 0.2%–1.0%).
Conclusions
Six in every 10 CMWs in Qatar have been infected, suggestive of reaching the herd immunity threshold. Infection severity was low, with only 1 in every 200 infections progressing to be severe or critical. Only 1 in every 10 infections had been previously diagnosed, which is suggestive of mostly asymptomatic or mild infections.
Background and purpose
Impulsivity is an aspect of personality and a major component of multiple neuropsychiatric conditions. In Parkinson’s disease, it has been associated with the expression of ...impulse control disorders, a highly prevalent non‐motor complication. Even though multiple tests of impulsivity have been used in this context, the impact of test choice has not been addressed. The aim was to evaluate whether different impulsivity measures in Parkinson’s disease share substantial inter‐scale and anatomical correlations or rather mirror different underlying phenomena.
Methods
In a consecutive sample of 89 Parkinson’s disease patients without impulse control disorders, four common tests were evaluated assessing different aspects of impulsivity: impulsiveness trait, decisions under implicit risk with and without losses, and delay discounting. Correlations among test scores were analysed and each score was used as a regressor in a set of grey matter volume (GMV) voxel‐based morphometry analyses to explore their brain structural correlates.
Results
No significant correlations were found between the different impulsivity tests. Furthermore, their structural brain correlates were divergent. Impulsiveness trait appeared to be associated with lower GMV in dorsal–lateral prefrontal cortices, implicit risk (with losses) with higher GMV in the left nucleus accumbens and lower left insular GMV, implicit risk (without losses) with higher GMV in the left lingual gyrus and lower GMV in the gyri recti and delay discounting with higher GMV in the left nucleus accumbens.
Conclusions
In Parkinson’s disease, different impulsivity measures reflect very dissimilar behavioural and brain structural correlates. Our results suggest that parkinsonian impulsivity is not a unitary phenomenon but rather a heterogeneous entity.
Amorphous nanoparticles of 50/50 TiO2/CdS mixtures were prepared and immobilized in poly 2, 2-bithiophene (PBTh) by occlusion electrodeposition. The photoelectrochemical (PEC) and impedance studies ...were performed in aqueous orthoorthophosphate and citrate electrolytes. Similar studies were also performed on pure amorphous cadmium sulfide (CdS) and titanium oxide (TiO2). Photoelectrochemical (PEC) studies revealed evidence of hole accumulations at the interfaces. Furthermore, PEC studies indicated that occlusion of CdS/TiO2 mixtures, prepared by mechanical mixing, in PBTh gave greater photocurrents than films of PBTh occluded with codeposted CdS/TiO2 mixtures. Transient time constant studies indicate that orthophosphate anions reduced the rate of electron –hole (e-h) recombination more than citrate, and further enhanced the generated photocurrent. Electrochemical impedance spectroscopic studies (EIS) revealed that occluded assembly films possess a porous-type structure, with multiple phases as indicated by the generation of Nyquist plots with composite semi-circles. The study also shows that orthophosphate anions enhanced the photoactivities at these interfaces more than citrate did. The studied assemblies showed photostability during a prolonged period for of illumination. The long photocurrent transient time recorded for these assemblies recommend it for potential energy capture and storage devices.
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