A search for Population III galaxies in CLASH. I. Singly-imaged candidates at high redshift

Population III galaxies are predicted to exist at high redshifts and may be rendered sufficiently bright for detection with current telescopes when gravitationally lensed by a foreground galaxy cluster. Population III galaxies that exhibit strong Lya emission should furthermore be identifiable from broadband photometry because of their unusual colors. Here, we report on a search for such objects at z > 6 in the imaging data from the Cluster Lensing And Supernova survey with Hubble (CLASH), covering 25 galaxy clusters in 16 filters. Our selection algorithm returns five singly-imaged candidates with Lya-like color signatures, for which ground-based spectroscopy with current 8-10 m class telescopes should be able to test the predicted strength of the Lya line. None of these five objects have been included in previous CLASH compilations of high-redshift galaxy candidates. However, when large grids of spectral synthesis models are applied to the study of these objects, we find that only two of these candidates are significantly better fitted by Population III models than by more mundane, low-metallicity stellar populations.Comment: 18 pages, 10 figures, accepted by Ap

Primordial star clusters at extreme magnification

Gravitationally lensed galaxies with magnification ~10-100 are routinely detected at high redshifts, but magnifications significantly higher than this are hampered by a combination of low probability and large source sizes. Magnifications of ~1000 may nonetheless be relevant in the case of intrinsically small, high-redshift objects with very high number densities. Here, we explore the prospects of detecting compact (< 10 pc), high-redshift (z > 7) Population III star clusters at such extreme magnifications in large-area surveys with planned telescopes like Euclid, WFIRST and WISH. We find that the planned WISH 100 sq. deg ultradeep survey may be able to detect a small number of such objects, provided that the total stellar mass of these star clusters is > 10000 solar masses. If candidates for such lensed Population III star clusters are found, follow-up spectroscopy of the surrounding nebula with the James Webb Space Telescope or groundbased Extremely Large Telescopes should be able to confirm the Population III nature of these objects. Multiband photometry of these objects with the James Webb Space Telescope also has the potential to confirm that the stellar initial mass function in these Population III star clusters is top-heavy, as supported by current simulations.Comment: 8 pages, 3 figures. v.2: Accepted for publication by MNRAS, with updated WISH detection limit

Hunting for dark halo substructure using submilliarcsecond-scale observations of macrolensed radio jets

Dark halo substructure may reveal itself through secondary, small-scale gravitational lensing effects on light sources that are macrolensed by a foreground galaxy. Here, we explore the prospects of using Very Long Baseline Interferometry (VLBI) observations of multiply-imaged quasar jets to search for submilliarcsecond-scale image distortions produced by various forms of dark substructures in the 1e3-1e8 Msolar mass range. We present lensing simulations relevant for the angular resolutions attainable with the existing European VLBI Network (EVN), the global VLBI array, and an upcoming observing mode in which the Atacama Large Millimeter Array (ALMA) is connected to the global VLBI array. While observations of this type would not be sensitive to standard cold dark matter subhalos, they can be used to detect more compact forms of halo substructure predicted in alternative structure formation scenarios. By mapping ~5 strongly lensed systems, it should be possible to detect or robustly rule out primordial black holes in the 1e3-1e6 Msolar mass range if they constitute >1% percent of the dark matter in these lenses. Ultracompact minihalos are harder to detect using this technique, but 1e6-1e8 Msolar ultracompact minihalos could in principle be detected if they constitute >10% of the dark matter.Comment: 13 pages, 8 figures; v.2 accepted for publication in MNRA

Global prevalence of nosocomial infection: A systematic review and meta-analysis

Objectives: Hospital-acquired infections (HAIs) are significant problems as public health issues which need attention. Such infections are significant problems for society and healthcare organizations. This study aimed to carry out a systematic review and a meta-analysis to analyze the prevalence of HAIs globally.   Methods: We conducted a comprehensive search of electronic databases including EMBASE, Scopus, PubMed and Web of Science between 2000 and June 2021. We found 7031 articles. After removing the duplicates, 5430 studies were screened based on the titles/abstracts. Then, we systematically evaluated the full texts of the 1909 remaining studies and selected 400 records with 29,159,630 participants for meta-analysis. Random-effects model was used for the analysis, and heterogeneity analysis and publication bias test were conducted.   Results: The rate of universal HAIs was 0.14 percent. The rate of HAIs is increasing by 0.06 percent annually. The highest rate of HAIs was in the AFR, while the lowest prevalence were in AMR and WPR. Besides, AFR prevalence in central Africa is higher than in other parts of the world by 0.27 (95% CI, 0.22-0.34). Besides, E. coli infected patients more than other micro-organisms such as Coagulase-negative staphylococci, Staphylococcus spp. and Pseudomonas aeruginosa. In hospital wards, Transplant, and Neonatal wards and ICU had the highest rates. The prevalence of HAIs was higher in men than in women.   Conclusion: We identified several essential details about the rate of HAIs in various parts of the world. The HAIs rate and the most common micro-organism were different in various contexts. However, several essential gaps were also identified. The study findings can help hospital managers and health policy makers identify the reason for HAIs and apply effective control programs to implement different plans to reduce the HAIs rate and the financial costs of such infections and save resources

Determination of Optimum Concentration of Benzimidazole Improving the Cathodic Disbonding Resistance of Epoxy Coating

This study is aimed to evaluate the effect of concentrated benzimidazole (BIM) on the cathodic disbonding (CP) of an epoxy coating applied on steel substrate. For this purpose, the polymeric coatings, formulated with different concentrations of BIM (0 wt.%, 0.5 wt.%, 0.75 wt.%, and 1 wt.%, were subjected to the CP test at the potential of −1.2 V vs. Ag/AgCl during 24 h immersion in 3.5 wt.% NaCl solutions. The optimum formulation was found through taking advantage of the CP test results, FESEM/EDX, and EIS data. Moreover, a pull-off test was used to measure the wet adhesion strength. For insight into the inhibition function of the organic inhibitor, the behavior of steel in the sodium chloride solutions, with and without BIM, was compared using EIS and surface analysis

Probing cold dark matter subhaloes with simulated ALMA observations of macrolensed sub-mm galaxies

If the dark matter haloes of galaxies contain large numbers of subhaloes as predicted by the Lambda cold dark matter model, these subhaloes are expected to appear in strong galaxy-galaxy lens systems as small-scale perturbations in individual images. We simulate observations of multiply lensed sub-mm galaxies at z similar to 2 as a probe of the dark matter halo of a lens galaxy at z similar to 0.5. We present detection limits for dark substructures based on a visibility plane analysis of simulated Atacama Large Millimeter/submillimeter Array (ALMA) data in bands 7, 8 and 9. We explore two effects: local surface brightness anomalies on angular scales similar to the Einstein radius and the astrometric shift of macroimages. This improves the sensitivity of our lens modelling to the mass of the lens perturber. We investigate the sensitivity of the detection of low-mass subhaloes to the projected position of the subhalo on the image plane as well as the source structure and inner density profile of the lens. We demonstrate that, using the most extended ALMA configuration, pseudo-Jaffe subhaloes can be detected with 99 per cent confidence down to M = 10(7)M(circle dot) . We show how the detection threshold for the three ALMA bands depends on the projected position of the subhalo with respect to the lensed images and conclude that, despite the highest nominal angular resolution, band 9 provides the poorest sensitivity due to observational noise. All simulations use the ALMA Full ops most extended ALMA configuration setup in CASA

The case against gravitational millilensing in the multiply-imaged quasar B1152+199

Previous very long baseline interferometry (VLBI) observations of the quasar B1152+199 at 5 GHz has revealed two images of a strongly lensed jet with seemingly discordant morphologies. Whereas the jet appears straight in one of the images, the other exhibits slight curvature on milliarcsecond scales. This is unexpected from the lensing solution and has been interpreted as possible evidence for secondary, small-scale lensing (millilensing) by a compact object with a mass of 10(5)-10(7) M-circle dot located close to the curved image. The probability for such a superposition is extremely low unless the millilens population has very high surface number density. Here, we revisit the case for millilensing in B1152+199 by combining new global-VLBI data at 8.4 GHz with two data sets from the European VLBI Network (EVN) at 5 GHz (archival), and the previously published 5 GHz Very Long Baseline Array (VLBA) data. We find that the new data with a more circular synthesized beam, exhibits no apparent milliarcsecond-scale curvature in image B. Various observations of the object spanning similar to 15 yr apart enable us to improve the constraints on lens system to the point that the only plausible explanation left for the apparent curvature is the artefact due to the shape of the synthesized beam

One-year prevalence and the association between SARS-CoV-2 cycle threshold, comorbidity and outcomes in population of Babol, North of Iran (2020-2021).

Background: The present study aimed to investigate the one-year prevalence of SARS-CoV-2, common comorbidities and demographic information among negative- and positive rRT-PCR in health care workers (HCW), hospitalized and outpatients. Also, the association between SARS-CoV-2 cycle threshold (Ct) and the outcomes of patients were analyzed in Babol, northern Iran. Methods: This large&#160;retrospective cross-sectional study was performed between March 2020 and March 2021. The records of 19232 hospitalized, outpatients and HCW suspected to COVID-19 were collected from teaching hospitals in the North of Iran. Results: Out of the 19232 suspected to COVID-19 patients, 7251 (37.7) had a positive rRT-PCR result; 652 (9), 4599 (63.4) and 2000 (27.6) of those were categorized as HCW, hospitalized and outpatients, respectively. Moreover, between the hospitalized and the outpatient group, 10.2 and 0.8 cases died, whereas no death cases were reported in the HCW. Furthermore, it seems that death rate was significantly different between the three groups of Ct value, the highest mortality in those with Ct between 21 and 30 (group B=7.6) and the lowest in the group with the highest Ct (between 31 and 40 = 5.5) (p&#60;0.001). Conclusion: In summary, 37.7 of cases were positive for SARS-CoV-2; of which, 63.4, 27.6 and 9 were hospitalized, outpatients and HCW, respectively. With regard to the mortality rate in hospitalized patients and the significant association with Ct under 20 and 30, it seems that the early detection and the initial quantification of SARS-CoV-2 in the first week of the conflict and therapeutic considerations to reduce the relative load can reduce the mortality rate