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Introduction: In Bangladesh, sexually transmitted infection (STI) services are available for all populations in public health facilities. However, STI services for key populations (KPs) at risk of HIV need specifically designed approaches that are predominantly administered to KPs through donor-supported service centers operated by non-government organizations (NGOs) and community-based organisations (CBOs). However, the steady decline in donor funding warrants a sustainable transition of STI services for the KPs into public health facilities. This article aimed to explore the service availability and readiness of public health facilities to provide STI services for the KPs. Methods: This qualitative study explored the service availability and readiness of public health facilities in three districts of Bangladesh by adapting the Service Availability and Readiness Assessment tool. We conducted 34 in-depth interviews,11 focus group discussions with KPs, and 29 key-informant interviews with healthcare providers, researchers, programme implementers and policy planners, in addition to series of direct observations at the public healthcare facilities. Data were analysed through thematic analysis, and categorised in relation to the WHO building blocks. Results: This study revealed that the public health system was generally not ready to serve the KPs' needs in terms of providing them with quality STI services. The 'service delivery' component, which is the most crucial facet of the public health system, was not ready to provide STI services to KPs. Findings also indicated that health workforce availability was limited in the primary and secondary healthcare layers but adequate in the tertiary layer, but needed to be oriented on providing culturally sensitised treatment. Counseling, an essential component of STI services, was neither ready nor available. However, health information systems and a few other components were partially ready, although this warrants systematic approaches to address these challenges. Conclusion: The findings show that public health facilities are yet to be fully ready to render STI services to KPs, especially in terms of service delivery and human and health resources. Therefore, it is not only integral to mobilize communities towards the uptake of public health services, but health systems need to be prepared to cater to their needs. [ABSTRACT FROM AUTHOR]

Background: Key populations (KPs) who are at risk of compromised situation of sexual and reproductive health and rights in Bangladesh constitute including males having sex with males, male sex workers, transgender women (locally known as hijra) and female sex workers. Globally, these key populations experience various sexual and reproductive health and rights burdens and unmet needs for ailments such as sexually transmitted infections including Neisseria Gonorrhoea, Chlamydia Trachomatis and human papillomavirus. Most key population focused interventions around the world, including Bangladesh, primarily address human immune deficiency virus and sexually transmitted infections-related concerns and provide syndromic management of sexually transmitted infections, other sexual and reproductive health and rights issues are remained overlooked that creates a lack of information in the related areas. There is currently no systematic research in Bangladesh that can produce representative data on sexual and reproductive health and rights among key populations, investigates their sexual and reproductive health and rights needs, how their needs evolve, and investigate underlying factors of sexual and reproductive health and rights issues that is crucial for informing more sexual and reproductive health and rights-friendly interventions for key populations. Keeping all these issues in mind, we are proposing to establish a sexual and reproductive health and rights surveillance system for key populations in Bangladesh. Method: The sexual and reproductive health and rights surveillance system will be established in Dhaka for males having sex with males, male sex workers and transgender women, and the other in Jashore for female sex workers. The duration will be for 3 years and data will be collected twice, in year one and year two adopting a mixed method repeated cross-sectional design. All key populations 15 years and above will be sampled. Behavioural data will be collected adopting a face-to-face technique and then biological samples will be collected. Those who will be found positive for human papillomavirus, will be referred to a government hospital for treatment. Free treatment will be provided to those who will be found positive for other sexually transmitted infections. In total, 2,240 key populations will be sampled. Written assent/consent will be taken from everyone. Data will be entered by Epi-Info and analysed by Stata. Report will be produced in every year. Discussion: This surveillance system will be the first of its kind to systematically assess the situation of sexual and reproductive health and rights among selected key populations in Bangladesh. It is expected that this study will provide insights needed for improving the existing sexual and reproductive health and rights intervention modalities for these vulnerable and marginalized key populations. [ABSTRACT FROM AUTHOR]

Introduction: One of the contributors to tuberculosis (TB) burden among vulnerable populations, such as sexual minority people, is the delay in case finding and notification. Given their socially excluded, hard-to-reach nature, community-led approaches need to be introduced to facilitate their screening of TB symptoms and their subsequent referral to TB healthcare providers. This article aimed to explore the existing challenges surrounding TB screening and referral, and the implementation facilitators and barriers of the proposed community-based TB screening model for sexual minority people in Dhaka, Bangladesh. Methods: This study followed the quasi-experimental design using mixed methods (i.e., qualitative and quantitative) approach. The study participants who were also a part of the community-led TB screening model included sexual minority people enrolled in HIV prevention interventions. In addition to quantitative inquiry, in-depth interviews were conducted on sexual minority people, focus group discussions were also conducted on them and HIV prevention service providers, and key-informant interviews were conducted on service providers, programmatic experts and TB researchers. Data were analyzed using content, contextual and thematic approaches. Results: The 'Six Steps in Quality Intervention Development' framework was used to guide the development of the community-based TB screening model. In Step 1 (identifying the problem), findings revealed low rates of TB screening among sexual minority people enrolled in the HIV prevention intervention. In Step 2 (identifying contextual factors for change), various individual, and programmatic factors were identified, which included low knowledge, low-risk perception, prioritization of HIV services over TB, and stigma and discrimination towards these populations. In Step 3 (deciding change mechanism), community-based screening approaches were applied, thus leading to Step 4 (delivery of change mechanism) which designed a community-based approach leveraging the peer educators of the HIV intervention. Step 5 (testing intervention) identified some barriers and ways forward for refining the intervention, such as home-based screening and use of social media. Step 6 (collecting evidence of effectiveness) revealed that the main strength was its ability to engage peer educators. Conclusion: This study indicates that a community-based peer-led TB screening approach could enhance TB screening, presumptive TB case finding and referral among these populations. Therefore, this study recommends that this approach should be incorporated to complement the existing TB program. [ABSTRACT FROM AUTHOR]

We examined the impact of dimethylsulfide (DMS) emissions on sulfate concentrations over the continental U.S. by using the Community Multiscale Air Quality (CMAQ) model version 5.4 and performing annual simulations without and with DMS emissions for 2018. DMS emissions enhance sulfate not only over seawater but also over land, although to a lesser extent. On an annual basis, the inclusion of DMS emissions increase sulfate concentrations by 36% over seawater and 9% over land. The largest impacts over land occur in California, Oregon, Washington, and Florida, where the annual mean sulfate concentrations increase by ~25%. The increase in sulfate causes a decrease in nitrate concentration due to limited ammonia concentration, especially over seawater, and an increase in ammonium concentration with a net effect of increased inorganic particles. The largest sulfate enhancement occurs near the surface (over seawater), and the enhancement decreases with altitude, diminishing to 10–20% at an altitude of ~5 km. Seasonally, the largest enhancement in sulfate over seawater occurs in summer, and the lowest in winter. In contrast, the largest enhancements over land occur in spring and fall due to higher wind speeds that can transport more sulfate from seawater into land. [ABSTRACT FROM AUTHOR]

• Average monthly EPI attendance reduced by 13.4% during the COVID interrupted period. • Average monthly immunizations were reduced by 38.3% during the interruption period. • Highest decline was observed in vaccines given early in infancy. • Reduced EPI attendance during the pandemic interruption period lasted only 3 months. • Mothers were comfortable to re-start EPI attendance with older than younger infants. The COVID-19 pandemic has affected the delivery of essential health services, such as routine immunization. We assessed the impact of the pandemic on the uptake of routine immunization in rural Gambia. We collected real-time vaccine administration data in the Basse and Fuladu West Health & Demographic Surveillance Systems from September 01, 2019, to December 31, 2020. We assessed the monthly number of Expanded Program on Immunization (EPI) clinic attendances and vaccines administered, comparing data during the baseline period (September 01, 2019–March 31, 2020), COVID-19 interruption period (April 01–June 30, 2020), initial recovery period (Jul 01–September 30, 2020) and the late recovery period (October 01–December 31, 2020). Compared to the baseline period, there was an overall average monthly decline of 13.4% in EPI attendance and 38.3% reduction in average monthly immunizations during the interruption period. This decrease was particularly noticeable for Bacille Calmette-Guérin (BCG) (47.2%), birth dose hepatitis B (Hep B) (46.9%), 1st dose pentavalent (Penta1) (43.1%), 1st dose pneumococcal conjugate vaccine (PCV1) (42.4%), and measles vaccines (15.5%). Comparing the late recovery to baseline period, average monthly EPI attendance was 5.3% higher, with 1.9% increase in average monthly immunizations. Monthly immunizations for BCG were 3.0% greater, 2.5% greater for Hep B, 22.7% greater for oral polio vaccine (OPV1), 2.0% less for Penta1, 19.2% less for Penta2, and 2.6% less for PCV1. The reduced EPI attendance during the pandemic interruption period lasted only 3 months. Significant recovery in EPI attendance occurred during the late recovery period, while rates of monthly immunization returned to pre-pandemic levels for most antigens. EPI programmes should implement strategies to deliver missed antigens when infants do present to EPI clinics, aware that missed doses may be age dependent. [ABSTRACT FROM AUTHOR]

The effects of the non-extensive statistics on the nonlinear propagation of perturbations have been studied within the scope of relativistic second order dissipative hydrodynamics with non-extensive equation of state. We have shown that the equations, describing the propagation of nonlinear waves under such situation admit solutions similar to that of KdV-type (Korteweg–De Vries) equations. Apart from their preserved solitonic behaviour the dissipative nature of these waves are also observed. The waves with larger amplitude and width dissipate less and propagate faster and these waves deplete more for both smaller values of Tsallis parameter (q) and temperature (T) of the medium. For vanishingly small transport coefficients the nonlinear waves show breaking nature. These findings suggest that the nature of the propagation of the nonlinear waves may serve as a good probe to differentiate between the extensive and non-extensive thermodynamic nature of a fluid, such as the quark-gluon plasma, produced in relativistic nuclear collisions. [ABSTRACT FROM AUTHOR]

The expression for the dynamical spectral structure of the density fluctuation near the QCD critical point has been derived using linear response theory within the purview of Israel–Stewart relativistic viscous hydrodynamics. The change in the spectral structure of the system as it approaches the critical point has been studied. The effects of the critical point have been introduced in the system through a realistic equation of state and the scaling behaviour of various transport coefficients and thermodynamic response functions. We have found that the Rayleigh and Brillouin peaks are distinctly visible when the system is away from the critical point but the peaks tend to merge near the critical point. The sensitivity of the structure of the spectral function on wave vector (k) of the sound wave has been demonstrated. It has been shown that the Brillouin peaks get merged with the Rayleigh peak because of the absorption of sound waves in the vicinity of the critical point. [ABSTRACT FROM AUTHOR]

The multiplicity, finite system size and collision energy dependence of heat capacity ( C V ), conformal symmetry breaking measure (CSBM) and speed of sound ( c s ) have been investigated using ALICE data for p + p collisions at s = 7 TeV. The aim of this study is to ascertain the possibility of formation of a thermalized medium in such collisions. We find that there is a threshold in charged particle multiplicity beyond which C V , CSBM and c s attain plateau. The presence of such threshold in multiplicity is further reflected in the variation of these quantities with center-of-mass energy ( s ). In order to have a grasp on experimentally obtained results, variation of average transverse momentum with multiplicity has also been studied. The experimental results have been contrasted with PYTHIA8 and it is found that PYTHIA8 is inadequate to explain the features reflected in these quantities, thereby indicating the possibility of thermalization in such small system. It is also observed that the finite size effects alone cannot explain the non-extensive nature of particle spectra in p + p collisions. [ABSTRACT FROM AUTHOR]

Biogenic emission of dimethyl sulfide (DMS) from seawater is the major natural source of sulfur into the atmosphere. In this study, we use an advanced air quality model (CMAQv5.2) with DMS chemistry to examine the impact of DMS emissions from seawater on summertime air quality over China. A national scale database of DMS concentration in seawater is established based on a 5‐year observational record in the East China seas including the Bohai Sea, the Yellow Sea, and the East China Sea. We employ a commonly used global database and also the newly developed local database of oceanic DMS concentration, calculate DMS emissions using three different parameterization schemes, and perform five different model simulations for July, 2018. Results indicate that in large coastal areas of China, the average DMS emissions flux obtained with the local database is 3 times higher than that resulting from the global database, with a mean value of 9.1 μmol m−2 day−1 in the Bohai Sea, 8.4 μmol m−2 day−1 in the Yellow Sea, and 13.4 μmol m−2 day−1 in the East China Sea. The total DMS emissions flux calculated with the Nightingale scheme is 42% higher than that obtained with the Liss and Merlivat scheme but is 15% lower than that obtained with the Wanninkhof scheme. Among the three parameterizations, results of the Liss and Merlivat scheme agree better with the ship‐based observations over China's coastal waters. DMS emissions with the Liss and Merlivat parametrization increase atmospheric sulfur dioxide (SO2) and sulfate (SO42−) concentration over the East China seas by 6.4% and 3.3%, respectively. Our results indicate that although the anthropogenic source is still the dominant contributor of atmospheric sulfur burden in China, biogenic DMS emissions source is nonnegligible. Key Points: The use of local database better reproduces DMS emission fluxes over China's seawaterThe LM86 parameterization (Liss & Merlivat, 1986, https://doi.org/10.1007/978‐94‐009‐4738‐2%5f5) produces the best performance among the three tested schemes in China's offshore watersThe marine DMS emissions increase SO2 and SO42‐ in the atmosphere of the eastern China Sea [ABSTRACT FROM AUTHOR]

Bromine and iodine chemistry has been updated in the Community Multiscale Air Quality (CMAQ) model to better capture the influence of natural emissions from the oceans on ozone concentrations. Annual simulations were performed using the hemispheric CMAQ model without and with bromine and iodine chemistry. Model results over the Northern Hemisphere show that including bromine and iodine chemistry in CMAQ not only reduces ozone concentrations within the marine boundary layer but also aloft and inland. Bromine and iodine chemistry reduces annual mean surface ozone over seawater by 25%, with lesser ozone reductions over land. The bromine and iodine chemistry decreases ozone concentration without changing the diurnal profile and is active throughout the year. However, it does not have a strong seasonal influence on ozone over the Northern Hemisphere. Model performance of CMAQ is improved by the bromine and iodine chemistry when compared to observations, especially at coastal sites and over seawater. Relative to bromine, iodine chemistry is approximately four times more effective in reducing ozone over seawater over the Northern Hemisphere (on an annual basis). Model results suggest that the chemistry modulates intercontinental transport and lowers the background ozone imported to the United States. • Bromine and iodine chemistry reduces ozone. • Iodine chemistry is more effective in reducing ozone than the bromine chemistry. • Bromine and iodine chemistry affects background ozone. • Bromine and iodine chemistry improves model performance. [ABSTRACT FROM AUTHOR]

The dynamical correlation of density fluctuation in quark gluon plasma with a critical end point has been investigated within the scope of the Müller–Israel–Stewart theory in the presence of static ultra-high external magnetic field. The dynamic structure factor of the density fluctuation exhibits three Lorentzian peaks in absence of external magnetic field – a central Rayleigh peak and two Brillouin peaks situated symmetrically on the opposite sides of the Rayleigh peak. The spectral structure displays five peaks in presence of the magnetic field due to the coupling of the magnetic field with the hydrodynamic fields in second-order hydrodynamics. The emergence of the extra peaks is due to the asymmetry in the pressure gradient caused by the external magnetic field in the system. Interestingly, it is observed that near the critical end point, all the Brillouin peaks disappear irrespective of the presence or absence of the external magnetic field. [ABSTRACT FROM AUTHOR]

B Correction to: b B I BMC Health Services Research i b B (2023) 23:979 b https://doi.org/10.1186/s12913-023-09996-2 Following publication of the original article [[1]], the authors identified an error caused by a typesetting mistake in the author name of the fourth author. A qualitative study of the readiness of the public health system to provide STI services to the key populations at risk of HIV in Bangladesh The incorrect author name is: AMRumayan Hasan The correct author name is: A M Rumayan Hasan The author group has been updated above and the original article [[1]] has been corrected. [Extracted from the article]

The power spectrum of the momentum distributions of particles have been estimated with Optical Glauber and Monte Carlo Glauber initial conditions for relativistic heavy ion collisions. The evaluation procedure adopted in this work is analogous to the one used in the calculation of power spectrum in Cosmic Microwave Background Radiation (CMBR). The power spectrum due to perturbations in the phase space distribution of the particles has also been evaluated. The perturbation in phase space has been evolved through the Boltzmann transport equation in an expanding quark–gluon plasma (QGP) background. The expansion of the QGP has been treated within the purview of (3 + 1)-dimensional relativistic hydrodynamics. We observe that the nonequilibrium effects introduced as perturbations in the phase space distributions can be traced through its variation with temperature which is distinctly different from the case of vanishing perturbation. A relation has been derived between the power spectrum and the flow harmonics. [ABSTRACT FROM AUTHOR]

Evolution of spatially anisotropic perturbation created in the system formed after Relativistic Heavy Ion Collisions has been studied. The microscopic evolution of the fluctuations has been examined within the ambit of Boltzmann Transport Equation (BTE) in a hydrodynamically expanding background. The expansion of the background composed of quark gluon plasma (QGP) is treated within the framework of relativistic hydrodynamics. Spatial anisotropic fluctuations with different geometries have been evolved through Boltzmann equation. It is observed that the trace of such fluctuation survives the evolution. Within the relaxation time approximation, analytical results have been obtained for the evolution of these anisotropies. Explicit relations between fluctuations and transport coefficients have been derived. The mixing of various Fourier (or k) modes of the perturbations during the evolution of the system has been explicitly demonstrated. This study is very useful in understanding the presumption that the measured anisotropies in the data from heavy ion collisions at relativistic energies imitate the initial state effects. The evolution of correlation function for the perturbation in pressure has been studied and shows that the initial correlation between two neighbouring points in real space evolves to a constant value at later time which gives rise to Dirac delta function for the correlation function in Fourier space. The power spectrum of the fluctuation in thermodynamic quantities (like temperature estimated in this work) can be connected to the fluctuation in transverse momentum of the thermal hadrons measured experimentally. The bulk viscous coefficient of the QGP has been estimated by using correlations of pressure fluctuation with the help of Green-Kubo relation. Angular power spectrum of the anisotropies has been estimated in the appendix. [ABSTRACT FROM AUTHOR]

We analyze hourly PM 2.5 (particles with an aerodynamic diameter of ≤2.5 μm) concentrations measured at the U.S. Embassy in Dhaka over the 2016–2021 time period and find that concentrations are seasonally dependent with the highest occurring in winter and the lowest in monsoon seasons. Mean winter PM 2.5 concentrations reached ∼165–175 μg/m3 while monsoon concentrations remained ∼30–35 μg/m3. Annual mean PM 2.5 concentration reached ∼5–6 times greater than the Bangladesh annual PM 2.5 standard of 15 μg/m3. The number of days exceeding the daily PM 2.5 standard of 65 μg/m3 in a year approached nearly 50%. Daily-mean PM 2.5 concentrations remained elevated (>65 μg/m3) for more than 80 consecutive days. Night-time concentrations were greater than daytime concentrations. The comparison of results obtained from the Community Multiscale Air Quality (CMAQ) model simulations over the Northern Hemisphere using 108-km horizontal grids with observed data suggests that the model can reproduce the seasonal variation of observed data but underpredicts observed PM 2.5 in winter months with a normalized mean bias of -13 to –32%. In the model, organic aerosol is the largest component of PM 2.5 , of which secondary organic aerosol plays a dominant role. Transboundary pollution has a large impact on the modeled PM 2.5 concentration in Dhaka, with an annual mean contribution of ∼40 μg/m3. • Daily mean PM 2.5 level in Dhaka exceeds 65 μg/m3 on 144 or more days per year. • A pollution episode in Dhaka can persist for more than 80 consecutive days. • Annual mean PM 2.5 concentration in Dhaka can reach nearly 100 μg/m3. • Organic aerosol is the largest component of PM 2.5 in Dhaka. • Annual mean contribution of transboundary pollution in Dhaka is ∼40 μg/m3. [ABSTRACT FROM AUTHOR]

Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic carbon, and bromide in seawater on ozone deposition. We perform a series of simulations using the hemispheric Community Multiscale Air Quality model for summer months in the Northern Hemisphere. Our results suggest that each chemical interaction enhances the ozone deposition velocity and decreases the atmospheric ozone mixing ratio over seawater. Iodide enhances the median deposition velocity over seawater by 0.023 cm s −1 , dissolved organic carbon by 0.021 cm s −1 , dimethylsulfide by 0.002 cm s −1 , and bromide by ∼0.0006 cm s −1 . Consequently, iodide decreases the median atmospheric ozone mixing ratio over seawater by 0.7 ppb, dissolved organic carbon by 0.8 ppb, dimethylsulfide by 0.1 ppb, and bromide by 0.02 ppb. In a separate model simulation, we account for the effect of dissolved salts in seawater on the Henry’s law constant for ozone and find that it reduces the median deposition velocity by 0.007 cm s −1 and increases surface ozone mixing ratio by 0.2 ppb. The combined effect of these processes increases the median ozone deposition velocity over seawater by 0.040 cm s −1 , lowers the atmospheric ozone mixing ratio by 5%, and slightly improves model performance relative to observations. [ABSTRACT FROM AUTHOR]

Abstract: We revise the Carbon Bond chemical mechanism to explicitly represent three Stabilized Criegee Intermediates (SCIs) and their subsequent reactions with sulfur dioxide, water monomer, and water dimer, and incorporate the reactions into the Community Multiscale Air Quality model. The reaction of sulfur dioxide with SCI produces sulfuric acid which partitions into sulfate. We examine the impact of sulfur dioxide oxidation by SCI on sulfate using two different measured rate constants for the reaction of sulfur dioxide and SCI. When we use the higher rate constant and emissions estimates from the Biogenic Emissions Inventory System, it enhances monthly mean sulfate in summer by ∼20% in biogenically active areas. Enhancements are driven primarily by SCI produced from the reactions of biogenically derived alkenes and ozone. The use of the lower rate constant only marginally enhances sulfate since it is 65 times lower than the higher rate constant. We performed several sensitivity analyses to investigate the impacts of uncertain biogenic emissions and SCI loss rates. When we use the higher rate constant and emissions estimates from the Model of Emissions of Gases and Aerosols from Nature, it enhances monthly mean sulfate by ∼75%. A simulation using the lowest reported rate constant for the reaction of SCI and water indicated the maximum enhancement of sulfate from this chemistry was up to 4 μg/m3 over a 24-h period in some locations in the Southeastern U.S. Predictions without the SCI reaction are lower than observed sulfate while predictions with the SCI reaction improve the agreements with observations. [Copyright &y& Elsevier]

Abstract: A new hydroxyl radical formation pathway via photo-excited nitrogen dioxide chemistry is incorporated into a chemistry-only box model as well as a 3D air quality model to examine its potential role on ozone formation and emission control strategy over the Pearl River Delta region in China. While the box model results suggest that the photo-excited nitrogen dioxide chemistry can substantially enhance ozone at high NOx and VOC concentrations, results of 3D air quality model show only a moderate increase in ozone. Though the photo-excited nitrogen dioxide chemistry enhances ozone by a maximum of 10ppbV over the urban area in the vicinity of abundant NOx and VOC concentrations, its typical enhancements range between 2 and 3ppbV. It enhances ozone within the entire planetary boundary layer under conditions featured in weak synoptic wind, abundant water vapor and strong land–sea breeze circulation. No significant improvement in model performance statistics for ozone is found with the photo-excited nitrogen dioxide chemistry. The photo-excited nitrogen dioxide chemistry marginally changes ozone responses to NOx and VOC emission controls. [Copyright &y& Elsevier]

Abstract: We examine the potential impacts of two additional sulfate production pathways using the Community Multiscale Air Quality modeling system. First we evaluate the impact of the aqueous-phase oxidation of S(IV) by nitrogen dioxide using two published rate constants, differing by 1–2 orders of magnitude. The reaction with alternate high and low rate constants enhances monthly mean wintertime sulfate by 4–20% and 0.4–1.2% respectively. The reaction does not significantly impact summertime sulfate. The higher sulfate predictions in winter compare better with the observed data as the model tends to underpredict sulfate concentrations both in winter and summer. We also investigate the potential impact of the gas-phase oxidation of sulfur dioxide by the Stabilized Criegee Intermediate (SCI) using a recently measured rate constant for its reaction with sulfur dioxide. Model results indicate that the gas-phase oxidation of sulfur dioxide by the SCI does not significantly affect sulfate concentrations due to the competing reaction of the SCI with water vapor. The current estimate of the rate constant for the SCI reaction with water vapor is too high for the SCI reaction with sulfur dioxide to significantly affect sulfate production. However, a sensitivity analysis using a lower rate constant for the water vapor reaction suggests that the SCI reaction with sulfur dioxide could potentially enhance sulfate production in the model. Further study is needed to accurately measure the rate constants of the aqueous-phase oxidation of S(IV) by nitrogen dioxide and the gas-phase reaction of the SCI with water vapor. [Copyright &y& Elsevier]

The impact of nitrous acid (HONO) chemistry on regional ozone and particulate matter in Pearl River Delta region was investigated using the community multiscale air quality (CMAQ) modeling system and the CB05 mechanism. Model simulations were conducted for a ten-day period in October 2004. Compared with available observed data, the model performance for NOx, SO2, PM10, and sulfate is reasonably good; however, predictions of HONO are an order of magnitude lower than observed data. The CB05 mechanism contains several homogenous reactions related to HONO. To improve themodel performance for HONO, direct emissions, two heterogeneous reactions, and two surface photolysis reactions were incorporated into the model. The inclusion of the additional formation pathways significantly improved simulatedHONOcompared with observed data. The addition ofHONO sources enhances daily maximum 8-hour ozone by up to 6 ppbV (8%) and daily mean PM2.5 by up to 17 ug/m3 (12%). They also affected ozone control strategy in Pearl River Delta region. [ABSTRACT FROM AUTHOR]

Abstract: Impact of the excited nitrogen dioxide (NO2 ∗) chemistry on air quality in the U.S. is examined using the Community Multiscale Air Quality (CMAQ) model for a summer month. Model simulations were conducted with and without the NO2 ∗ chemistry. The largest impact of the NO2 ∗ chemistry in the eastern U.S. occurred in the northeast and in the western U.S. occurred in Los Angeles. While the single largest daily maximum 8-h ozone (O3) increased by 9 ppbv in eastern U.S. and 6 ppbv in western U.S., increases on most days were much lower. No appreciable change in model performance statistics for surface-level O3 predictions relative to measurements is noted between simulations with and without the NO2 ∗ chemistry. Based on model calculations using current estimates of tropospheric emission burden, the NO2 ∗ chemistry can increase the monthly mean daytime hydroxyl radicals (OH) and nitrous acid (HONO) by a maximum of 28% and 100 pptv, respectively. [Copyright &y& Elsevier]

The impact of the QCD critical point on the propagation of nonlinear waves has been studied. The effects have been investigated within the scope of second-order causal dissipative hydrodynamics by incorporating the critical point into the equation of state, and the scaling behavior of transport coefficients and of thermodynamic response functions. Near the critical point, the nonlinear waves are found to be significantly damped which may result in the disappearance of the Mach cone effects of the away side jet. Such damping may lead to enhancement in the fluctuations of elliptic and higher flow coefficients. Therefore, the disappearance of Mach cone effects and the enhancement of fluctuations in flow harmonics in the event-by-event analysis may be considered as signals of the critical endpoint. [ABSTRACT FROM AUTHOR]

Predictions of nitrous acid from the Community Multiscale Air Quality modeling system are compared with the measurements from the 2001 Northeast Oxidant and Particle Study. Four different sources of nitrous acid were considered in the study: gas-phase reactions, direct emissions, a heterogeneous reaction, and a surface photolysis reaction. When only gas-phase reactions were considered in the model, the diurnally averaged mean bias, the normalized mean bias, the root mean square error, and the normalized mean error of the model were −1.01ppbv, −98%, 1.05ppbv, and 98%, respectively. However, the diurnally averaged mean bias, normalized mean bias, the root mean square error, and the normalized mean error of the model improved to −0.42ppbv, −41%, 0.45ppbv, and 41%, respectively, when all sources were considered. Model results suggest that the heterogeneous reaction and the surface photolysis reaction are the most important sources of nitrous acid in the atmosphere, accounting for about 86% of the predicted nitrous acid. Emissions and the gas-phase reactions were relatively minor sources and accounted for only 14% of the predicted nitrous acid. Model predictions suggest that the heterogeneous reaction is the most significant source of nitrous acid at night, while the surface photolysis reaction is the most significant source during the day. The addition of these sources increased the diurnally averaged hydroxyl radicals and ozone by 10% and 1.4ppbv, respectively. [Copyright &y& Elsevier]

An updated and expanded version of the Carbon Bond mechanism (CB05) has been incorporated into the Community Multiscale Air Quality (CMAQ) modeling system to more accurately simulate wintertime, pristine, and high-altitude situations. The CB05 mechanism has nearly 2 times the number of reactions relative to the previous version of the Carbon Bond mechanism (CB-IV). While the expansions do provide more detailed treatment of urban areas, most of the new reactions involve biogenics, toxics, and species potentially important to particulate formation and acid deposition. Model simulations were performed using the CB05 and the CB-IV mechanisms for the winter and summer of 2001. For winter with the CB05 mechanism, ozone, aerosol nitrate, and aerosol sulfate concentrations were within 1% of the results obtained with the CB-IV mechanism. Organic carbon concentrations were within 2% of the results obtained with the CB-IV mechanism. However, formaldehyde and hydrogen peroxide concentrations were lower by 25% and 32%, respectively, during winter with the CB05 mechanism. For the summer, ozone concentrations increased by 8% with the CB05 mechanism relative to the CB-IV mechanism. The aerosol sulfate, aerosol nitrate, and organic carbon concentrations with the CB05 mechanism decreased by 8%, 2%, and 10%, respectively. The formaldehyde and hydrogen peroxide concentrations with the CB05 mechanism were lower by 12% and 47%, respectively, during summer. Model performance with the CB05 mechanism improved at high-altitude conditions and in rural areas for ozone. Model performance also improved for organic carbon with the CB05 mechanism. [ABSTRACT FROM AUTHOR]

This paper presents model estimates of the effect of chlorine emissions on atmospheric ozone concentrations in the eastern United States. The model included anthropogenic molecular chlorine emissions, anthropogenic hypochlorous acid emissions from cooling towers and swimming pools, and chlorine released from sea-salt aerosols. The release of chlorine emissions from sea-salt aerosols was modeled using heterogeneous reactions involving chloride ions in aerosols and three gas-phase species. The gas-phase chlorine chemistry was combined with the Carbon Bond Mechanism and incorporated into the Community Multiscale Air Quality modeling system. Air quality model simulations were performed for July 2001 and the results obtained with and without chlorine emissions were analyzed. When chlorine emissions were included in the model, ozone concentrations increased in the Houston, Texas, and New York–New Jersey areas. The daily maximum 1-h ozone concentrations increased by up to 12 parts per billion by volume (ppbv) in the Houston area and 6 ppbv in the New York–New Jersey area. The daily maximum 8-h ozone concentrations increased by up to 8 ppbv in the Houston area and 4 ppbv in the New York–New Jersey area. The monthly average daily maximum 1-h ozone concentration increased by up to 3 ppbv in the Houston area, but the increases in the monthly average daily maximum 1-h ozone concentration in the New York–New Jersey area were small. Chlorine emissions and chemistry enhanced the volatile organic compound oxidation rates and, thereby, increased the ozone production rate. [ABSTRACT FROM AUTHOR]

An indoor air quality model was used to predict dynamic particle mass concentrations based on homogeneous chemical mechanisms and partitioning of semi-volatile products to particles. The ozone–limonene reaction mechanism was combined with gas-phase chemistry of common atmospheric organic and inorganic compounds and incorporated into the indoor air quality model. Experiments were conducted in an environmental chamber to investigate secondary particle formation resulting from ozone/limonene reactions. Experimental results indicate that significant fine particle growth occurs due to the interaction of ozone and limonene and subsequent intermediate by-products. Secondary particle mass concentrations were estimated from the measured particle size distribution. Predicted particle mass concentrations were in good agreement with experimental results—generally within ∼25% at steady-state conditions. Both experimental and predicted results suggest that air exchange rate plays a significant role in determining secondary fine particle levels in indoor environments. Secondary particle mass concentrations are predicted to increase substantially with lower air exchange rates, an interesting result given a continuing trend toward more energy efficient buildings. Lower air exchange rates also shifted the particle size distribution toward larger particle diameters. Secondary particle mass concentrations are also predicted to increase with higher outdoor ozone concentrations, higher outdoor particle concentrations, higher indoor limonene emission rates, and lower indoor temperatures. [Copyright &y& Elsevier]

Abstract: Estimates of non-industrial source ammonia emissions in Texas were developed through the use of published emission factors and activity data for those sources. A total of 64 non-industrial source emission sub-categories were addressed, each falling into one of seven major source categories: animal husbandry, fertilizer applications, on-road vehicles, non-road sources, municipal wastewater disposal, domestic sources, and natural soil and vegetation. Annual statewide ammonia emissions were initially estimated to be 921,000 metric tons, with greater than 50% originating from natural soil and vegetation. However, estimates for pine and oak forests were characterized as having a great deal of uncertainty. A series of field sampling events were conducted to determine ammonia fluxes from pine and oak forest floors in east Texas. Both dynamic and static chamber methods were used. The ammonia flux averaged 0.09kgkm−2 month−1 for pine forests and 0.13kgkm−2 month−1 for oak forests. These values are significantly lower than those previously measured and cited in the published literature. However, the ammonia fluxes measured in east Texas forests are reasonably consistent with those predicted using mechanistic models for evergreen pine and deciduous broadleaf forests in Alabama, California, Colorado, and Tennessee. Statewide annual ammonia emissions estimates, revised using the newly developed ammonia fluxes for oak and pine forests in Texas, dropped from 921,000 to 467,000 metric tons. The relative contribution of ammonia emissions from pine and oak forests dropped from 49% to less than 1%. Animal husbandry was predicted to be the dominant non-industrial source, accounting for approximately 77% of non-industrial source ammonia emissions. [Copyright &y& Elsevier]

Consumer products can emit significant quantities of terpenes, which can react with ozone (O[sub3]). Resulting by-products include compounds with low vapor pressures that contribute to the growth of secondary organic aerosols (SOAs). The focus of this study was to evaluate the potential for SOA growth, in the presence of O[sub3], following the use of a lime-scented liquid air freshener, a pine-scented solid air freshener, a lemon-scented general-purpose cleaner, a wood floor cleaner, and a perfume. Two chamber experiments were performed for each of these five terpene-containing agents, one at an elevated O[sub3] concentration and the other at a lower O[sub3] concentration. Particle number and mass concentrations increased and O[sub3] concentrations decreased during each experiment. Experiments with terpene-based air fresheners produced the highest increases in particle number and mass concentrations. The results of this study clearly demonstrate that homogeneous reactions between O[sub3] and terrenes from various consumer products can lead to increases in fine particle mass concentrations when these products are used indoors. Particle increases can occur during periods of elevated outdoor O[sub3] concentrations or indoor O[sub3] generation, coupled with elevated terpene releases. Human exposure to fine particles can be reduced by minimizing indoor terpene concentrations or O[sub3] concentrations. [ABSTRACT FROM AUTHOR]

Experiments were conducted in an 11 m3 environmental chamber to investigate secondary particles resulting from homogeneous reactions between ozone and α-pinene. Experimental results indicate that rapid fine particle growth occurs due to homogeneous reactions between ozone and α-pinene, and subsequent gas-to-particle partitioning of the products. A new indoor air quality model was used to predict dynamic particle mass concentrations based on detailed homogeneous chemical mechanisms and partitioning of semi-volatile products to particles. Chamber particle mass concentrations were estimated from measured particle size distributions and were in reasonable agreement with results predicted from the model. Both experimental and model results indicate that secondary particle mass concentrations increase substantially with lower air exchange rates. This is an interesting result, given a continuing trend toward more energy-efficient buildings. Secondary particle mass concentrations are also predicted to increase with lower indoor temperatures, higher outdoor ozone concentrations, higher outdoor particle concentrations, and higher indoor α-pinene emissions rates. [Copyright &y& Elsevier]

Estimates the indoor hydroxyl radical concentrations with the use of an emerging indoor air quality model which employs an atmospheric chemistry model to simulate indoor homogenous reactions. Comparison of results with those taken from previous studies; Results of base case application; Effects of indoor alkene emission rates on indoor hydroxyl radical concentrations.

Comparison of lightning flash data from the National Lightning Detection Network (NLDN) and from the World Wide Lightning Location Network (WWLLN) over the contiguous United States (CONUS) for the 2016–2018 period reveals temporally and spatially varying flash rates that would influence lightning NOx (LNOx) production due to known detection efficiency differences especially during summer months over land (versus over ocean). However, the lightning flash density differences between the two networks show persistent seasonal patterns over geographical regions (e.g., land versus ocean). Since the NLDN data are considered to have higher accuracy (lightning detection with >95% efficiency), we developed scaling factors for the WWLLN flash data based on the ratios of WWLLN to NLDN flash data over time (months of year) and space. In this study, sensitivity simulations using the Community Multiscale Air Quality (CMAQ) model are performed utilizing the original data sets (both NLDN and WWLLN) and the scaled WWLLN flash data for LNOx production over the CONUS. The model performance of using the different lightning flash datasets for ambient O3 and NOx mixing ratios that are directly impacted by LNOx emissions and the wet and dry deposition of oxidized nitrogen species that are indirectly impacted by LNOx emissions is assessed based on comparisons with ground-based observations, vertical profile measurements, and satellite products. During summer months, the original WWLLN data produced less LNOx emissions (due to its lower lightning detection efficiency) compared to the NLDN data, which resulted in less improvement in model performance than the simulation using NLDN data as compared to the simulation without any LNOx emissions. However, the scaled WWLLN data produced LNOx estimates and model performance comparable with the NLDN data, suggesting that scaled WWLLN may be used as a substitute for the NLDN data to provide LNOx estimates in air quality models when the NLDN data are not available (e.g., due to prohibitive cost or lack of spatial coverage). [ABSTRACT FROM AUTHOR]

The Community Multiscale Air Quality (CMAQ) model has been used for regulatory purposes at the US EPA and in the research community for decades. In 2012, we released the WRF-CMAQ coupled model that enables aerosol information from CMAQ to affect meteorological processes through direct effects on shortwave radiation. Both CMAQ and WRF-CMAQ are considered limited area models. Recently, we have extended domain coverage to global scale linking the meteorological Model for Prediction Across Scales – Atmosphere (MPAS-A, hereafter referred simply to as MPAS) with CMAQ to form the MPASCMAQ global coupled model. To configure these three different models, i.e. CMAQ (offline), WRF-CMAQ, and MPASCMAQ, we have developed the Advanced Air Quality Modelling System (AAQMS) for constructing each of them effortlessly. We evaluate this newly-built MPAS-CMAQ coupled model using two global configurations: a 120 km uniform mesh and a 92–25 km variable mesh with the finer area over North America. Preliminary computational tests show good scalability and model evaluation, a three years simulation (2014–2016) for the uniform mesh case and a monthly simulation of January and July 2016 for the variable mesh case, on ozone and PM2.5, show reasonable performance with respect to observations. The 92–25 km configuration has a high bias in wintertime surface ozone across the United States and this bias is consistent with the 120 km result. Summertime surface ozone in the 92–25 km configuration is less biased than the 120 km case. The MPAS-CMAQ system reasonably reproduces the daily variability of daily average PM from the Air Quality System (AQS) network. [ABSTRACT FROM AUTHOR]

We implement oceanic dimethylsulfide (DMS) emissions and its atmospheric chemical reactions into the Community Multiscale Air Quality (CMAQv53) model and perform annual simulations without and with DMS chemistry to quantify its impact on tropospheric composition and air quality over the Northern Hemisphere. DMS chemistry enhances both sulfur dioxide (SO 2) and sulfate (SO 4 2 − ) over seawater and coastal areas. It enhances annual mean surface SO 2 concentration by +46 pptv and SO 4 2 − by +0.33 μg/m3 and decreases aerosol nitrate concentration by −0.07 μg/m3 over seawater compared to the simulation without DMS chemistry. The changes decrease with altitude and are limited to the lower atmosphere. Impacts of DMS chemistry on SO 4 2 − are largest in the summer and lowest in the fall due to the seasonality of DMS emissions, atmospheric photochemistry and resultant oxidant levels. Hydroxyl and nitrate radical-initiated pathways oxidize 75% of the DMS while halogen-initiated pathways oxidize 25%. DMS chemistry leads to more acidic particles over seawater by decreasing aerosol pH. Increased SO 4 2 − from DMS enhances atmospheric extinction while lower aerosol nitrate reduces the extinction so that the net effect of DMS chemistry on visibility tends to remain unchanged over most of the seawater. • Dimethylsulfide enhances sulfate over seawater and coastal areas. • The impact of dimethylsulfide on sulfate is the largest in the summer. • Hydroxyl and nitrate radical-initiated pathways oxidize 75% and halogen-initiated pathways oxidize 25% of dimethylsulfide. • Dimethylsulfide leads to more acidic particles. [ABSTRACT FROM AUTHOR]

Background Accurate estimation of diarrhea incidence from facility-based surveillance requires estimating the population at risk and accounting for case patients who do not seek care. The Enterics for Global Health (EFGH) Shigella surveillance study will characterize population denominators and healthcare-seeking behavior proportions to calculate incidence rates of Shigella diarrhea in children aged 6–35 months across 7 sites in Africa, Asia, and Latin America. Methods The Enterics for Global Health (EFGH) Shigella surveillance study will use a hybrid surveillance design, supplementing facility-based surveillance with population-based surveys to estimate population size and the proportion of children with diarrhea brought for care at EFGH health facilities. Continuous data collection over a 24 month period captures seasonality and ensures representative sampling of the population at risk during the period of facility-based enrollments. Study catchment areas are broken into randomized clusters, each sized to be feasibly enumerated by individual field teams. Conclusions The methods presented herein aim to minimize the challenges associated with hybrid surveillance, such as poor parity between survey area coverage and facility coverage, population fluctuations, seasonal variability, and adjustments to care-seeking behavior. [ABSTRACT FROM AUTHOR]

Background The Gambia, located in West Africa, is one of 7 country sites conducting the Enterics for Global Health (EFGH) Shigella Surveillance Study to establish incidence and consequence of Shigella -associated medically attended diarrhea among children 6–35 months old. Methods Here we describe the study site and research experience, sociodemographic characteristics of the study catchment area, facilities of recruitment for diarrhea case surveillance, and known care-seeking behavior for diarrheal illness. We also describe The Gambia's healthcare system and financing, current vaccine schedule and Shigella vaccine adaptation, local diarrhea management guidelines and challenges, and antibiotic resistance patterns in the region. Conclusions The EFGH study in The Gambia will contribute to the multisite network of Shigella surveillance study and prepare the site for future vaccine trials. In addition, the data produced will inform policy makers about prevention strategies and upcoming Shigella vaccine studies among children in this setting. [ABSTRACT FROM AUTHOR]

Background Rigorous data management systems and planning are essential to successful research projects, especially for large, multicountry consortium studies involving partnerships across multiple institutions. Here we describe the development and implementation of data management systems and procedures for the Enterics For Global Health (EFGH) Shigella surveillance study—a 7-country diarrhea surveillance study that will conduct facility-based surveillance concurrent with population-based enumeration and a health care utilization survey to estimate the incidence of Shigella- -associated diarrhea in children 6 to 35 months old. Methods The goals of EFGH data management are to utilize the knowledge and experience of consortium members to collect high-quality data and ensure equity in access and decision-making. During the planning phase before study initiation, a working group of representatives from each EFGH country site, the coordination team, and other partners met regularly to develop the data management systems for the study. Results This resulted in the Data Management Plan, which included selecting REDCap and SurveyCTO as the primary database systems. Consequently, we laid out procedures for data processing and storage, study monitoring and reporting, data quality control and assurance activities, and data access. The data management system and associated real-time visualizations allow for rapid data cleaning activities and progress monitoring and will enable quicker time to analysis. Conclusions Experiences from this study will contribute toward enriching the sparse landscape of data management methods publications and serve as a case study for future studies seeking to collect and manage data consistently and rigorously while maintaining equitable access to and control of data. [ABSTRACT FROM AUTHOR]

In this work, we study electrical conductivity and Hall conductivity in the presence of electromagnetic field using Relativistic Boltzmann Transport Equation with Relaxation Time Approximation. We evaluate these transport coefficients for a strongly interacting system consisting of nearly massless particles which is similar to Quark-Gluon Plasma and is likely to be formed in heavy-ion collision experiments. We explicitly include the effects of magnetic field in the calculation of relaxation time. The values of magnetic field are obtained for all the centrality classes of Au + Au collisions at s NN = 200 GeV and Pb + Pb collisions at s NN = 2.76 TeV. We consider the three lightest quark flavors and their corresponding antiparticles in this study. We estimate the temperature dependence of the electrical conductivity and Hall conductivity for different strengths of magnetic field. We observe a significant dependence of temperature on electrical and Hall conductivity in the presence of magnetic field. [ABSTRACT FROM AUTHOR]

We assessed whether personal exposure to household air pollution [PM2.5 and black carbon (BC)] is associated with lung functions (FEV1, FVC, and their ratio) in non-smoking adults in rural Bangladesh. We measured personal exposure to PM2.5 using gravimetric analysis of PM2.5 mass and BC by reflectance measurement between April 2016 and June 2019. The average 24-hour PM2.5 and BC concentration was 141.0μgm−3 and 13.8μgm−3 for females, and 91.7 μgm−3 and 10.1 μgm−3 for males, respectively. A 1 μgm−3 increase in PM2.5 resulted in a 0.02 ml reduction in FEV1, 0.43 ml reduction in FVC, and 0.004% reduction in FEV1/FVC. We also found a similar inverse relationship between BC and lung functions (9.6 ml decrease in FEV1 and 18.5 ml decrease in FVC per 1μgm−3 increase in BC). A higher proportion of non-smoking biomass fuel users (50.1% of the females and 46.7% of the males) had restrictive patterns of lung function abnormalities, which need further exploration. [ABSTRACT FROM AUTHOR]

Introduction: The COVID-19 pandemic incurred numerous impediments on day-to-day emergency medical services including Opioid Substitution Therapy (OST) for People Who Inject Drugs (PWID). To prevent treatment cessation and lost to follow-up, we tried to implement an alternate mitigating intervention like telehealth. Methodology: This research was conducted on a cohort of OST clients during the COVID-19 pandemic (from 1st April 2020 to 31st March 2021) in Narayanganj, a port city adjacent to the capital Dhaka and one of the most COVID-affected districts, with a high PWID and HIV burden. The participants were male, female and transgender women who were all ex-PWID and were under OST services. A telehealth intervention model was designed and implemented in the OST clinic at Narayangonj. Quantitative data were collected during pre and post-intervention of telehealth services. Results: A total of 297 OST clients of Narayangonj were provided with telehealth services from April 2020 to March 2021. The participants were predominantly male (98.7%), 37.7% were between 30–39 years of age. 39.4% of the telephone calls were related to COVID-19-related symptoms followed by 21.7% for opioid withdrawal, 12.5% for COVID-19 & vaccine-related information, 11.3% for chronic diseases like diabetes, hypertension and asthma, 9.3% for Skin and Soft Tissue Infection (SSTI), and 5.8% for methadone-related effects. There was an improvement in treatment retention (14.4% to 87%), loss to follow-up (20% to 8%), and overdose-related death (1.3% to 0%) from pre to post intervention of telehealth services. Conclusion: From our experience, we found that the telehealth intervention is beneficial for the OST clients and thus ensures treatment continuity and retention, both of which serve as crucial success indicators of the OST programme. Using simply the mobile phone, this intervention can reduce structural and logistical needs like clinic spaces and fewer human resources, ensuring cost-effectiveness and value for money. [ABSTRACT FROM AUTHOR]

The high-multiplicity pp collisions at the Large Hadron Collider energies with various heavy-ion-like signatures have warranted a deeper understanding of the underlying physics and particle production mechanisms. It is a common practice to use experimental data on the hadronic transverse momentum ( p T ) spectra to extract thermodynamical properties of the system formed in heavy-ion and high multiplicity pp collisions. The non-availability of event topology dependent experimental data for pp collisions at s = 13 TeV on the spectra of non-strange and strange hadrons constrains us to use the PYTHIA8 simulated numbers to extract temperature-like parameters to study the event shape and multiplicity dependence of specific heat capacity, conformal symmetry breaking measure (CSBM) and speed of sound. The observables show a clear dependence on event multiplicity and event topology. Thermodynamics of the system is largely governed by the light particles because of their relatively larger abundances. In this regards, a threshold in the particle production, N ch ≃ (10–20) in the final state multiplicity emerges out from the present study, confirming some of the earlier findings in this direction. As for heavier hadrons with relatively small abundances, a similar threshold is observed for ⟨ N ch ⟩ ≃ 40 hinting towards formation of a thermal bath where all the heavier hadrons are in equilibrium. [ABSTRACT FROM AUTHOR]

Sulfate plays an important role in atmospheric haze in China, which has received considerable attention in recent years. Various types of parameterization methods and heterogeneous oxidation rates of SO 2 have been used in previous studies. However, properly representing heterogeneous sulfate formation in air quality models remains a big challenge. In this study, we quantified the heterogeneous oxidation reaction using experimental results that approximate the haze conditions in China. Firstly, a series of experiments were conducted to investigate the heterogeneous uptake of SO 2 with different relative humidity (RH) levels and the presence of NH 3 and NO 2 on natural dust surfaces. Then the uptake coefficients for heterogeneous oxidation of SO 2 to sulfate at different RH under NH 3 and NO 2 coexistence were parameterized based on the experimental results and implemented in the Community Multiscale Air Quality modeling system (CMAQ). Simulation results suggested that this new parameterization improved model performance by 6.6% in the simulation of wintertime sulfate concentrations for Beijing. The simulated maximum growth rate of SO 4 2− during a heavy pollution period increased from 0.97 μg m−3 h−1 to 10.11 μg m−3 h−1. The heterogeneous oxidation of SO 2 in the presence of NH 3 contributed up to 23% of the sulfate concentration during heavy pollution periods. Image 1 • Uptake coefficients of SO 2 on dust with coexistence of NH 3 and NO 2 were obtained. • New parameterization was proposed based on experimental results under different RHs. • The new parameterization can improve sulfate simulation in wintertime in CMAQ. • Impact of NH 3 on heterogeneous formation of sulfate in wintertime is non-negligible. [ABSTRACT FROM AUTHOR]

Background: In low-resource settings, it is challenging to ascertain the burden and causes of under-5 mortality as many deaths occur outside health facilities. We aimed to determine the causes of childhood deaths in rural Gambia using verbal autopsies (VA). Methodology: We used WHO VA questionnaires to conduct VAs for deaths under-5 years of age in the Basse and Fuladu West Health and Demographic Surveillance Systems (HDSS) in rural Gambia between September 01, 2019, and December 31, 2021. Using a standardized cause of death list, two physicians assigned causes of death and discordant diagnoses were resolved by consensus. Results: VAs were conducted for 89% (647/727) of deaths. Of these deaths, 49.5% (n = 319) occurred at home, 50.1% (n = 324) in females, and 32.3% (n = 209) in neonates. Acute respiratory infection including pneumonia (ARIP) (33.7%, n = 137) and diarrhoeal diseases (23.3%, n = 95) were the commonest primary causes of death in the post-neonatal period. In the neonatal period, unspecified perinatal causes of death (34.0%, n = 71) and deaths due to birth asphyxia (27.3%, n = 57) were the commonest causes of death. Severe malnutrition (28.6%, n = 185) was the commonest underlying cause of death. In the neonatal period, deaths due to birth asphyxia (p-value<0.001) and severe anaemia (p-value = 0.03) were more likely to occur at hospitals while unspecified perinatal deaths (p-value = 0.01) were more likely to occur at home. In the post-neonatal period, deaths due to ARIP (p-value = 0.04) and diarrhoeal disease (p-value = 0.001) were more likely to occur among children aged 1–11 months and 12–23 months respectively. Conclusion: According to VA analysis of deaths identified within two HDSS in rural Gambia, half of deaths amongst children under-5 in rural Gambia occur at home. ARIP and diarrhoea, and the underlying cause of severe malnutrition remain the predominant causes of child mortality. Improved health care and health-seeking behaviour may reduce childhood deaths in rural Gambia. [ABSTRACT FROM AUTHOR]

The oceans are the main source of natural halogen and sulfur compounds, which have a significant influence on the oxidizing capacity of the marine atmosphere; however, their impact on the air quality of coastal cities is currently unknown. We explore the effect of marine halogens (Cl, Br and I) and dimethyl sulfide (DMS) on the air quality of a large coastal city through a set of high-resolution (4-km) air quality simulations for the urban area of Los Angeles, US, using the Community Multiscale Air Quality (CMAQ model). The results indicate that marine halogen emissions decrease ozone and nitrogen dioxide levels up to 5 ppbv and 2.5 ppbv, respectively, in the city of Los Angeles. Previous studies suggested that the inclusion of chlorine in air quality models leads to the generation of ozone in urban areas through photolysis of nitryl chloride (ClNO 2 ). However, we find that when considering the chemistry of Cl, Br and I together the net effect is a reduction of surface ozone concentrations. Furthermore, combined ocean emissions of halogens and DMS cause substantial changes in the levels of key urban atmospheric oxidants such as OH, HO 2 and NO 3 , and in the composition and mass of fine particles. Although the levels of ozone, NO 3 and HO x are reduced, we find a 10% increase in secondary organic aerosol (SOA) mean concentration, attributed to the increase in aerosol acidity and sulfate aerosol formation when combining DMS and bromine. Therefore, this new pathway for enhanced SOA formation may potentially help with current model under predictions of urban SOA. Although further observations and research are needed to establish these preliminary conclusions, this first city-scale investigation suggests that the inclusion of oceanic halogens and DMS in air quality models may improve regional air quality predictions over coastal cities around the world. [ABSTRACT FROM AUTHOR]

This paper proposes Gibbs free-energy-based objective functions in the parameter fitting of activity coefficient and specific heat capacity of ions. The activity coefficient parameters are fitted through the averaged squared error between the Gibbs free energy calculated by using the measured activity coefficient data and that by using the model equation. The standard-state heat capacity parameters of ions are fitted through the minimization of the average squared error between the Gibbs free energy of dissolution calculated through the saturation activity over a temperature range and that calculated through the standard-state chemical potential as a function of temperature via standard-state specific heat. This methodology is tested with Bromley and Pitzer models. The proposed methodology reduces the need for experiments and avoids the uncertainty of extrapolation to infinite dilution when determining standard-state specific heat of ions. The proposed methodology provides solubility estimates that are more accurate than those of the common methodology, except for low temperatures in the Pitzer model where the common approach is somehow slightly more accurate. In addition, the proposed methodology enables accurate modeling with limited data: solubility over temperature range, activity coefficient data up to some concentrated range not covering saturation, and no ionic specific heat data. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic represents an unprecedented challenge for clinical research. The Pneumococcal Vaccine Schedules (PVS) study is a non-inferiority, interventional trial in which infants resident in 68 geographic clusters are randomised to two different schedules for pneumococcal vaccination. From September 2019 onwards, all infants resident in the study area became eligible for trial enrolment at all Expanded Programme on Immunisation (EPI) clinics in the study area. Surveillance for clinical endpoints is conducted at all 11 health facilities in the study area. PVS is conducted as a collaboration between the Medical Research Council Unit The Gambia (MRCG) at LSHTM and the Gambian Ministry of Health (MoH). The COVID-19 pandemic caused many disruptions to PVS. MRCG instructed interventional studies that participant enrolment be suspended on 26 March 2020, and a public health emergency was declared in The Gambia on 28 March 2020. Enrolment in PVS restarted on 1 July 2020 and was suspended again on 5 August 2020 after The Gambia experienced a sharp increase in COVID-19 cases in late July 2020 and restarted again on 1 September 2020. During periods of suspended enrolment of infants at EPI clinics, PVS continued safety surveillance at health facilities, albeit with disruptions. During the periods of suspended enrolment, infants who had been enrolled before 26 March 2020 continued to receive the PCV schedule to which they had been randomly allocated based on their village of residence, whereas all other infants received the standard PCV schedule. Throughout 2020 and 2021, the trial faced numerous technical and operational challenges: disruption to MoH delivery of EPI services and clinical care at health facilities; episodes of staff illness and isolation; disruption of MRCG transport, procurement, communications and human resource management; and also a range of ethical, regulatory, sponsorship, trial monitoring and financial challenges. In April 2021, a formal review concluded that the pandemic had not compromised the scientific validity of PVS and that the trial should continue as per protocol. The continuing challenges that COVID-19 poses to PVS, and other clinical trials will persist for some time. [ABSTRACT FROM AUTHOR]

Background: While rotavirus causes severe diarrheal disease in children aged <5 years, data on other viral causes in sub-Saharan Africa are limited. Methods: In the Vaccine Impact on Diarrhea in Africa study (2015–2018), we analyzed stool from children aged 0–59 months with moderate-to-severe diarrhea (MSD) and without diarrhea (controls) in Kenya, Mali, and The Gambia using quantitative polymerase chain reaction. We derived the attributable fraction (AFe) based on the association between MSD and the pathogen, accounting for other pathogens, site, and age. A pathogen was attributable if the AFe was ≥0.5. The severity of attributable MSD was defined by a modified Vesikari score (mVS). Monthly cases were plotted against temperature and rainfall to assess seasonality. Results: Among 4840 MSD cases, proportions attributed to rotavirus, adenovirus 40/41, astrovirus, and sapovirus were 12.6%, 2.7%, 2.9%, and 1.9%, respectively. Attributable rotavirus, adenovirus 40/41, and astrovirus MSD cases occurred at all sites, with mVS of 11, 10, and 7, respectively. MSD cases attributable to sapovirus occurred in Kenya, with mVS of 9. Astrovirus and adenovirus 40/41 peaked during the rainy season in The Gambia, while rotavirus peaked during the dry season in Mali and The Gambia. Conclusions: In sub-Saharan Africa, rotavirus was the most common cause of MSD; adenovirus 40/41, astrovirus, and sapovirus contributed to a lesser extent among children aged <5 years. Rotavirus- and adenovirus 40/41-attributable MSD were most severe. Seasonality varied by pathogen and location. Efforts to increase the coverage of rotavirus vaccines and to improve prevention and treatment for childhood diarrhea should continue. Among children <5 years, rotavirus, adenovirus 40/41, and astrovirus cause moderate to severe diarrhea (MSD) in Kenya, Mali, and The Gambia, and sapovirus causes MSD in Kenya. Rotavirus and adenovirus 40/41 MSD have the highest severity. [ABSTRACT FROM AUTHOR]

Background: As part of the Vaccine Impact on Diarrhea in Africa (VIDA) Study, we examined the prevalence, clinical presentation, and seasonality of Cryptosporidium in children to understand its relative burden after the introduction of rotavirus vaccine. Methods: VIDA was a 3-year, age-stratified, matched case-control study of medically attended acute moderate-to-severe diarrhea (MSD) in children aged 0–59 months residing in censused populations at sites in Kenya, Mali, and The Gambia. Clinical and epidemiologic data were collected at enrollment, and a stool sample was tested for enteropathogens by quantitative PCR. An algorithm was created based on the organism's cycle threshold (Ct) and association with MSD to identify the subset of Cryptosporidium PCR-positive (Ct <35) cases most likely to be attributed to MSD. Clinical outcomes were assessed at 2–3 months after enrollment. Results: One thousand one hundred six (22.9%) cases of MSD and 873 controls (18.1%) were PCR positive for Cryptosporidium; 465 cases (42.0%) were considered attributable to Cryptosporidium, mostly among children 6–23 months. Cryptosporidium infections peaked in The Gambia and Mali during the rainy season, while in Kenya they did not have clear seasonality. Compared with cases with watery MSD who had a negative PCR for Cryptosporidium, cases with watery MSD attributed to Cryptosporidium were less frequently dehydrated but appeared more severely ill using a modified Vesikari scale (38.1% vs 27.0%; P < 0.001), likely due to higher rates of hospitalization and intravenous fluid administration, higher prevalence of being wasted or very thin very thin (23.4% vs 14.7%; P < 0.001), and having severe acute malnutrition (midupper arm circumference <115 mm, 7.7% vs 2.5%; P < 0.001). On follow-up, Cryptosporidium-attributed cases had more prolonged and persistent episodes (43.2% vs 32.7%; P <0.001) and linear growth faltering (change in height-for-age z score between enrollment and follow-up: −0.29 vs −0.17; P < 0.001). Conclusions: The burden of Cryptosporidium remains high among young children in sub-Saharan Africa. Its propensity to cause illness and further impact children longer term by compromising nutritional status early in life calls for special attention to enable appropriate management of clinical and nutritional consequences. The burden of Cryptosporidium remains high among young children in sub-Saharan Africa. Its propensity to cause illness and further impact children longer term by compromising nutritional status early in life necessitates appropriate management of clinical and nutritional consequences. [ABSTRACT FROM AUTHOR]

Background: Previously studied risk factors for rotavirus vaccine failure have not fully explained reduced rotavirus vaccine effectiveness in low-income settings. We assessed the relationship between histo-blood group antigen (HBGA) phenotypes and clinical rotavirus vaccine failure among children <2 years of age participating in the Vaccine Impact on Diarrhea in Africa Study in 3 sub-Saharan African countries. Methods: Saliva was collected and tested for HBGA phenotype in children who received rotavirus vaccine. The association between secretor and Lewis phenotypes and rotavirus vaccine failure was examined overall and by infecting rotavirus genotype using conditional logistic regression in 218 rotavirus-positive cases with moderate-to-severe diarrhea and 297 matched healthy controls. Results: Both nonsecretor and Lewis-negative phenotypes (null phenotypes) were associated with decreased rotavirus vaccine failure across all sites (matched odds ratio, 0.30 [95% confidence interval: 0.16–0.56] or 0.39 [0.25–0.62], respectively]. A similar decrease in risk against rotavirus vaccine failure among null HBGA phenotypes was observed for cases with P[8] and P[4] infection and their matched controls. While we found no statistically significant association between null HBGA phenotypes and vaccine failure among P[6] infections, the matched odds ratio point estimate for Lewis-negative individuals was >4. Conclusions: Our study demonstrated a significant relationship between null HBGA phenotypes and decreased rotavirus vaccine failure in a population with P[8] as the most common infecting genotype. Further studies are needed in populations with a large burden of P[6] rotavirus diarrhea to understand the role of host genetics in reduced rotavirus vaccine effectiveness. Assessing histo-blood group antigen (HBGA) phenotypes and rotavirus vaccine failure among children in sub-Saharan Africa, we found a significant relationship between null HBGA phenotypes and decreased rotavirus vaccine failure in a population with P[8] as the common infecting genotype. [ABSTRACT FROM AUTHOR]