Modes of Transmission of Severe Acute Respiratory Syndrome-Coronavirus-2 (SARS-CoV-2) and Factors Influencing on the Airborne Transmission: A Review

The multiple modes of SARS-CoV-2 transmission including airborne, droplet, contact, and fecal–oral transmissions that cause coronavirus disease 2019 (COVID-19) contribute to a public threat to the lives of people worldwide. Herein, different databases are reviewed to evaluate modes of transmission of SARS-CoV-2 and study the effects of negative pressure ventilation, air conditioning system, and related protection approaches of this virus. Droplet transmission was commonly reported to occur in particles with diameter \u3e5 µm that can quickly settle gravitationally on surfaces (1–2 m). Instead, fine and ultrafine particles (airborne transmission) can stay suspended for an extended period of time (≥2 h) and be transported further, e.g., up to 8 m through simple diffusion and convection mechanisms. Droplet and airborne transmission of SARS-CoV-2 can be limited indoors with adequate ventilation of rooms, by routine disinfection of toilets, using negative pressure rooms, using face masks, and maintaining social distancing. Other preventive measures recommended include increasing the number of screening tests of suspected carriers of SARS-CoV-2, reducing the number of persons in a room to minimize sharing indoor air, and monitoring people’s temperature before accessing a building. The work reviews a body of literature supporting the transmission of SARS-CoV-2 through air, causing COVID-19 disease, which requires coordinated worldwide strategies

Properties of the transient X-ray pulsar Swift J1816.7--1613 and its optical companion

We present results of investigation of the poorly studied X-ray pulsar Swift J1816.7--1613 during its transition from the type I outburst to the quiescent state. Our studies are based on the data obtained from X-ray observatories \textit{Swift}, \textit{NuSTAR} and \textit{Chandra} alongside with the latest IR data from UKIDSS/GPS and \textit{Spitzer}/GLIMPSE surveys. The aim of the work is to determine parameters of the system: the strength of the neutron star magnetic field and the distance to the source, which are required for the interpretation of the source behaviour in the framework of physically motivated models. No cyclotron absorption line was detected in the broad-band energy spectrum. However, the timing analysis hints at the typical for the X-ray pulsars magnetic field from a few $\times 10^{11}$ to a few $\times 10^{12}$ G. We also estimated type of the IR-companion as a B0-2e star located at distance of 7--13~kpc.Comment: 8 pages, 7 figures, accepted for publication in A&

Characteristics and Assessing Biological Risks of Airborne Bacteria in Waste Sorting Plant

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m−3) were: Staphylococcus sp. (72.4) \u3e Micrococcus sp. (52.2) \u3e Bacillus sp. (30.3) \u3e Enterococcus sp. (24.0) \u3e Serratia marcescens (20.1) \u3e E. coli (19.1) \u3e Pseudomonas sp. (16.0) \u3e Nocardia sp. (1.9). The lifetime average daily dose (LADD) for the inhalation and dermal routes for the intake of airborne bacteria ranged from 3.7 × 10−3 ≤ LADDInhalation ≤ 2.07 × 101 CFU (kg d)−1 and 4.75 × 10−6 ≤ LADDDermal ≤ 1.64 × 10−5 CFU (kg d)−1, respectively. Based on a sensitivity analysis (SA), the concentration of airborne bacteria (C) and the exposure duration (ED) had the most effect on the LADDInhalation and LADDDermal for all sampling locations. Although the Hazard Quotient of airborne bacteria was HQ \u3c 1, an acceptable level, the indoor/outdoor ratio (1.5 ≤ I/O ≤ 6.6) of airborne bacteria typically exceeded the threshold value (I/O \u3e 2), indicating worker’s exposure to an infected environment. Therefore, in the absence of sufficient natural ventilation the indoor ambient conditions of the WPCSP studied should be controlled by supplying mechanical ventilation

Broad-band analysis of X-ray pulsar 2S 1845–024

We present the results of a detailed investigation of the poorly studied X-ray pulsar 2S 1845−024 based on data obtained at the NuSTAR observatory during the type I outburst in 2017. Neither pulse phase-averaged nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used data obtained from other X-ray observatories (Swift, XMM-Newton and Chandra) to study the spectral properties as a function of orbital phase. The analysis reveals a high hydrogen column density for the source reaching ∼1024 cm−2 around periastron. Using high-quality Chandra data we were able to obtain an accurate localization of 2S 1845−024 at 18h48m16s.8 and Dec. = −2◦25'25".1 (J2000), which allowed us to use infrared (IR) data to roughly classify the optical counterpart of the source as an OB supergiant at a distance of ≳15 kpc.</p

First detection of VHE gamma-ray emission from TXS 1515-273, study of its X-ray variability and spectral energy distribution

We report here on the first multi-wavelength (MWL) campaign on the blazar TXS 1515-273, undertaken in 2019 and extending from radio to very-high-energy gamma rays (VHE). Up until now, this blazar had not been the subject of any detailed MWL observations. It has a rather hard photon index at GeV energies and was considered a candidate extreme high-synchrotronpeaked source. MAGIC observations resulted in the first-time detection of the source in VHE with a statistical significance of 7.6$\sigma$. The average integral VHE flux of the source is 6 $\pm$ 1% of the Crab nebula flux above 400 GeV. X-ray coverage was provided by Swift-XRT, XMMNewton, and NuSTAR. The long continuous X-ray observations were separated by $\sim$ 9 h, both showing clear hour scale flares. In the XMM-Newton data, both the rise and decay timescales are longer in the soft X-ray than in the hard X-ray band, indicating the presence of a particle cooling regime. The X-ray variability timescales were used to constrain the size of the emission region and the strength of the magnetic field. The data allowed us to determine the synchrotron peak frequency and classify the source as a flaring high, but not extreme, synchrotron peaked object. Considering the constraints and variability patterns from the X-ray data, we model the broad-band spectral energy distribution. We applied a simple one-zone model, which could not reproduce the radio emission and the shape of the optical emission, and a two-component leptonic model with two interacting components, enabling us to reproduce the emission from radio to VHE band

The comparative responsiveness of Hospital Universitario Princesa Index and other composite indices for assessing rheumatoid arthritis activity

Objective To evaluate the responsiveness in terms of correlation of the Hospital Universitario La Princesa Index (HUPI) comparatively to the traditional composite indices used to assess disease activity in rheumatoid arthritis (RA), and to compare the performance of HUPI-based response criteria with that of the EULAR response criteria. Methods Secondary data analysis from the following studies: ACT-RAY (clinical trial), PROAR (early RA cohort) and EMECAR (pre-biologic era long term RA cohort). Responsiveness was evaluated by: 1) comparing change from baseline (Delta) of HUPI with Delta in other scores by calculating correlation coefficients; 2) calculating standardised effect sizes. The accuracy of response by HUPI and by EULAR criteria was analyzed using linear regressions in which the dependent variable was change in global assessment by physician (Delta GDA-Phy). Results Delta HUPI correlation with change in all other indices ranged from 0.387 to 0.791); HUPI's standardized effect size was larger than those from the other indices in each database used. In ACT-RAY, depending on visit, between 65 and 80% of patients were equally classified by HUPI and EULAR response criteria. However, HUPI criteria were slightly more stringent, with higher percentage of patients classified as non-responder, especially at early visits. HUPI response criteria showed a slightly higher accuracy than EULAR response criteria when using Delta GDA-Phy as gold standard. Conclusion HUPI shows good responsiveness in terms of correlation in each studied scenario (clinical trial, early RA cohort, and established RA cohort). Response criteria by HUPI seem more stringent than EULAR''s

ENVIRONMENTAL IMPACTS ASSESSMENT OF INDUSTRIAL ESTATE PROVIDING WITH MANAGERIAL PROCESS

At this study, an environmental impact assessment establishment of Shahzand Industrial Estate in Arak at the central part of Iran was investigated. After collection of data and analysis of the findings, the positive and negative impacts resulted from establishment of the industrial estate were investigated, using the Leopold Matrix and Scaling checklist methods providing the managerial solutions in order to minimize the environmental harmful impacts. The existing environmental situation was investigated and then environmental impact alternatives were determined. This was done regarding to the amount and kind of predicted pollutions for industrial estate at the construction and operational phases. The environmental impact assessment of the investigated estate was studied at the three terms of immediate, direct and indirect impacts at the short, medium and long term. By expanding of Leopold Matrix to four parted matrix, in addition to amount, importance and extend of the impacts, the remaining duration of impact in the environment were assessed as a separate factor in environmental impact assessment. The results of the study with two alternatives, such as; No (performance of the project with no concern for environmental issue) and as yes (performance of the project with application of the environmental harmful impacts) were studied in construction and operation phases. The impact assessment of "NO" property resulted (-1065), therefore the execution of project was rejected, but after reducing the harmful impact performance which were resulted (+1095) has been accepted. Therefore, method of reducing harmful environmental impacts along with environmental management programs introduced and accepted in this study

Broad-band analysis of X-ray pulsar 2S 1845–024

We present the results of a detailed investigation of the poorly studied X-ray pulsar 2S 1845−024 based on data obtained at the NuSTAR observatory during the type I outburst in 2017. Neither pulse phase-averaged nor phase-resolved spectra of the source show evidence for a cyclotron absorption feature. We also used data obtained from other X-ray observatories (Swift, XMM-Newton and Chandra) to study the spectral properties as a function of orbital phase. The analysis reveals a high hydrogen column density for the source reaching ∼1024 cm−2 around periastron. Using high-quality Chandra data we were able to obtain an accurate localization of 2S 1845−024 at RA = 18$^{\mathrm{h}}48^{\mathrm{m}}16{{\overset{\text{s}}{.}}}8$ and Dec = $-2^\circ25^{\prime}25{{\overset{\prime\prime}{.}}}1$ (J2000), which allowed us to use infrared (IR) data to roughly classify the optical counterpart of the source as an OB supergiant at a distance of ≳15 kpc