Evaluation of the COSMO model (v5.1) in polarimetric radar space – impact of uncertainties in model microphysics, retrievals and forward operators

Sensitivity experiments with a numerical weather prediction (NWP) model and polarimetric radar forward operator (FO) are conducted for a long-duration stratiform event over northwestern Germany to evaluate uncertainties in the partitioning of the ice water content and assumptions of hydrometeor scattering properties in the NWP model and FO, respectively. Polarimetric observations from X-band radar and retrievals of hydrometeor classifications are used for comparison with the multiple experiments in radar and model space. Modifying the critical diameter of particles for ice-to-snow conversion by aggregation (Dice) and the threshold temperature responsible for graupel production by riming (Tgr), was found to improve the synthetic polarimetric moments and simulated hydrometeor population, while keeping the difference in surface precipitation statistically insignificant at model resolvable grid scales. However, the model still exhibited a low bias (lower magnitude than observation) in simulated polarimetric moments at lower levels above the melting layer (−3 to −13 ∘C) where snow was found to dominate. This necessitates further research into the missing microphysical processes in these lower levels (e.g. fragmentation due to ice–ice collisions) and use of more reliable snow-scattering models to draw valid conclusions.

Audit partner workload, gender and audit quality

PurposeThe paper aims to investigate the relation between the auditor's workload (LogAPW) and audit quality. Further, it explores whether the presence of a female audit partner (hereafter FEM) influences the LogAPW effect on audit quality.Design/methodology/approachA dataset of 1,629 firm-year observations from 181 companies listed in the NASDAQ OMX Stockholm for the years 2010–2018 has been analyzed. The testable hypotheses have been tested using least squares regressions clustered at the Swedish public-listed companies (client-firm) level.FindingsThe research findings first indicate that overburdened audit partners (APS) are associated with lower-quality audits, consistent with the “busyness hypothesis.” Nevertheless, the adverse association turns to be positive for FEMs, supporting the thesis that FEMs have more tendency, as compared to their male counterparts, to preserve their partnership's position in the public-audit firms. Collectively, these results seem sound, as the results hold unchanged after controlling for the endogeneity concerns and provide the same conclusion for a host of additional measures for both the client-firms' discretionary accruals and the LogAPW.Research limitations/implicationsEven though a lower magnitude of the client-firms' discretionary accruals corresponds to a lower-opportunistic behavior of managers, the research is limited to by which lower values of earnings management reflect a better-quality financial reporting. Given that the empirical analysis has been confined to the Swedish Corporation, the regression results might not be generalizable for other countries with different contextual features.Practical implicationsThe study might participate to the ongoing debate about the introduction of more women to the public-audit firms' elite positions (e.g. partnership) by providing evidence for the favorable female auditor effect on the quality of the client-firms' financial reporting.Originality/valueThe regression results provide a preliminary evidence on how does the presence of a FEM mitigate the inverse relation between the LogAPW and audit quality, which is an issue that has not been examined before.

Effect of Pin Geometry and Orientation on Friction and Wear Behavior of Nickel-Coated EN8 Steel Pin and Al6061 Alloy Disc Pair

Most mechanical systems (in particular, gear transmission system) undergo relative motion which results in increased friction phenomenon (friction coefficient, stresses, and wear rate) and thereby results in loss of efficiency. Mechanical parts undergo relative motion in different geometry configurations and orientations that induce a different state of stress as a result of friction. Till date, attempts are being made to minimize the friction with full sphere pin geometry configuration. The present work focused to reduce the frictional and wear rate, and experiments are conducted with tribo-pairs. i.e., nickel-coated pin surface slide against Al6061 alloy disc. The friction studies are carried out at different loads and geometries of pin surfaces (sphere and hemisphere configured at different orientations such as full sphere and hemisphere configured at 0°, 45°, and 90°) to induce different stress states with reference to sliding directions. Change in the geometry of EN8 pin material and their orientation with reference to sliding direction resulted in a different state of stress. The resulting stress levels were examined under the scanning electron microscope, which revealed the mechanisms of adhesion, abrasion, and extrusion. At a lower magnitude of orientation and load, the extent of asperity breaking lessens and material removal from pin surface decreases. Abrasion wear mechanism was observed corresponding to full sphere configuration on Al 6061 disc, whereas adhesive wear mechanisms are seen with hemisphere pins. The amount of aluminum transfer on pin surface with a hemisphere pin is comparatively more than that of full sphere configuration. At a lower magnitude of state of stress, the mechanism of sliding was dominated by the adhesion effect. At a higher level of state of stress, the mechanism of sliding was dominated by abrasion and extrusion.

Reviewing the elements of marine ice cliff instability

Antarctica’s ice sheets are the largest potential sea-level rise contributors, but projections of future sea-level rise yield wide ranges of estimates under different emission scenarios. An important factor in the variability of estimates is marine ice cliff instability (MICI). Inclusion of MICI yields the highest potential sea-level rise cases but also the largest uncertainty due to poor understanding of the factors that control it and the mechanisms of how it happens. Although evidence for MICI has been implied by paleo-ice sheet studies and observations of keel plough mark on sea-floor, recent statistical and modelling studies have suggested a lower magnitude of MICI effect on sea-level rise due to thinning of ice sheets and buttressing forces exerted on potentially failing cliffs. This paper reviews the factors that control MICI with the goal of identifying priorities for modern ice sheet studies to better bound the estimates.

Longitudinal Variations of M. tuberculosis-Induced IFN-γ Responses in HIV-Negative Pregnant Women Exposed to Tuberculosis

IntroductionPregnancy triggers an alteration of the immune functions and increases the risk of developing the active tuberculosis (TB) symptoms in exposed women. The effect of pregnancy on the Mycobacterium tuberculosis-specific immune responses used for most of the TB immunodiagnostic assays is not well documented. Here we investigated the changes in the M. tuberculosis-specific IFN-γ production in age-matched pregnant and non-pregnant women according to their TB exposition status.MethodsWe conducted a prospective cohort study on HIV-seronegative pregnant and non-pregnant women with compatible pulmonary TB symptoms addressed to TB healthcare facilities in Antananarivo, Madagascar. Active pulmonary TB was bacteriologically assessed with culture from sputum samples. Clinical data and blood samples were collected at inclusion and after 6 months of follow-up for each individual included. Whole blood samples were stimulated with QuantiFERON TB-Gold Plus (QFT-P) assay antigens. Plasma IFN-γ concentrations were then assessed by ELISA.ResultsA total of 284 women were investigated for the study including 209 pregnant women without confirmed TB (pNTB), 24 pregnant women with bacteriologically confirmed active TB (pATB), 16 non-pregnant women with active TB (ATB), and 35 non-pregnant healthy donors (HC). At inclusion, IFN-γ responses are lower in the pregnant women compared to their age-matched non-pregnant counterparts and independently of their TB status. Among the pregnant women, higher concentrations of M. tuberculosis-specific IFN-γ were observed in those exposed to TB, but with a lower magnitude in the active TB compared to the latently infected pregnant women (p < 0.05 with TB1 and p < 0.01 with TB2). After 6 months of follow-up, the M. tuberculosis-specific IFN-γ responses return to their baseline concentrations except for the pregnant women treated for TB for which none of the QFT-P positive reversed to negative (0%, 0/10) at the end of their TB treatment.ConclusionThese results support the concept of specific immune priorities characterized by a concomitant reduction in inflammatory immunity during pregnancy and corroborate the important role of activating the M. tuberculosis-specific immune responses to control the infection when the pregnant women are exposed to the pathogen.

Measuring the impact of COVID-19 vaccination and immunity waning: a modelling study for Portugal

Vaccination strategies to control COVID-19 have been ongoing worldwide since the end of 2020. Understanding their possible effect is key to prevent future disease spread. Using a modelling approach, this study intends to measure the impact of the COVID-19 Portuguese vaccination strategy on the effective reproduction number and explore three scenarios for vaccine effectiveness waning. Namely, the no-immunity-loss, 1-year and 3-years of immunity duration scenarios. We adapted an age-structured SEIR deterministic model and used Portuguese hospitalisation data for the model calibration. Results show that, although the Portuguese vaccination plan had a substantial impact in reducing overall transmission, it might not be sufficient to control disease spread. A significant vaccination coverage of those above 5 years old, a vaccine effectiveness against disease of at least 80% and softer non-pharmaceutical interventions (NPIs), such as mask usage and social distancing, would be necessary to control disease spread in the worst scenario considered. The immunity duration scenario of 1-year displays a resurgence of COVID-19 hospitalisations by the end of 2021, the same is observed in 3-year scenario although with a lower magnitude. The no-immunity-loss scenario presents a low increase in hospitalisations. In both the 1-year and 3-year scenarios, a vaccination boost of those above 65 years old would result in a 53% and 38% peak reduction of non-ICU hospitalisations, respectively. These results suggest that NPIs should not be fully phased-out but instead be combined with a fast booster vaccination strategy to reduce healthcare burden.

Comparative assessment of aerosol optical properties over a mega city and an adjacent urban area in India

The present work revolves around the comparative analysis of aerosol optical properties in a mega city, Delhi and in a nearby urban area, Rohtak. It is pertinent to note that despite of the close proximity and similar meteorological conditions, the two study locations show significant differences in aerosol characteristics. The study is conducted using ground based Sky-radiometer measurements for a period of one year. The mean annual Aerosol Optical Depth (AOD) at 500 nm over Delhi and Rohtak is observed to be 1.01 and 0.73 respectively, with correlation coefficient of 0.67 and mean absolute difference of 0.51. The magnitude of AOD in Delhi is higher than in Rohtak throughout the year, except in post-monsoon season. The difference in Angstrom exponent (alpha) between the stations is minimal. However, lower magnitude of alpha is observed in Rohtak, indicating presence of more concentration of coarse-mode particles. Single Scattering Albedo (SSA) also shows seasonal variation with significantly lower values in Delhi throughout the year, indicating contribution of absorbing type of aerosols (like black carbon). The volume concentration in fine-size is found to be higher in Delhi than in Rohtak, indicating combined effect of dust, vehicular, biomass burning and industrial emissions. The aerosol classification via relationship between AOD and alpha shows that urban/biomass burning (U/B) aerosols are dominant in Delhi and mixed type (MT) aerosols in Rohtak during winter and pre-monsoon.

Racial and Ethnic Disparities in COVID-19 Infection and Hospitalization in the Active Component US Military

Objectives. To assess COVID-19 disparities in the active component US military with an emphasis on race and ethnicity. Methods. In this retrospective cohort study, we calculated the incidence of COVID-19 testing, infection, and hospitalization in the active component US military in calendar year 2020. Results. Overall, 61.3 per 100 population per year were tested for COVID-19, 10.4% of tests were positive, and 1.1% of infected individuals were hospitalized. Non-Hispanic Blacks and Hispanics had a rate of testing for COVID-19 similar to that of Whites but had a higher risk of infection (adjusted risk ratio [ARR] = 1.25 and 1.26, respectively) and hospitalization (ARR = 1.28 and 1.21, respectively). Conclusions. Although of lower magnitude than seen in civilian populations, racial and ethnic disparities in COVID-19 infection and hospitalizations exist in the US military despite universal eligibility for health care, similar rate of testing, and adjustment for comorbidities and other factors. Simply making health care coverage available may be insufficient to ensure health equity. Interventions to mitigate disparities in the US military should target the patient, provider, health care system, and society at large. (Am J Public Health. 2021;111(12):2194–2201. https://doi.org/10.2105/AJPH.2021.306527 )

Variable-resolution building exposure modelling for earthquake and tsunami scenario-based risk assessment: an application case in Lima, Peru

We propose the use of variable resolution boundaries based on central Voronoi tessellations (CVTs) to spatially aggregate building exposure models for risk assessment to various natural hazards. Such a framework is especially beneficial when the spatial distribution of the considered hazards presents intensity measures with contrasting footprints and spatial correlations, such as in coastal environments. This work avoids the incorrect assumption that a single intensity value from hazards with low spatial correlation (e.g. tsunami) can be considered to be representative within large-sized geo-cells for physical vulnerability assessment, without, at the same time, increasing the complexity of the overall model. We present decoupled earthquake and tsunami scenario-based risk estimates for the residential building stock of Lima (Peru). We observe that earthquake loss models for far-field subduction sources are practically insensitive to the exposure resolution. Conversely, tsunami loss models and associated uncertainties depend on the spatial correlations of the hazard intensities as well as on the resolution of the exposure models. We note that for the portfolio located in the coastal area exposed to both perils in Lima, the ground shaking dominates the losses for lower-magnitude earthquakes, whilst tsunamis cause the most damage for larger-magnitude events. For the latter, two sets of existing empirical flow depth fragility models are used, resulting in large differences in the calculated losses. This study, therefore, raises awareness about the uncertainties associated with the selection of fragility models and spatial aggregation entities for exposure modelling and loss mapping.

Improvement of Porous GaN-Based UV Photodetector with Graphene Cladding

This work presents the role of graphene in improving the performance of a porous GaN-based UV photodetector. The porous GaN-based photodetector, with a mean pore diameter of 35 nm, possessed higher UV sensitivity, about 95% better compared to that of the as-received (non-porous) photodetector. In addition, it exhibits a lower magnitude of leakage current at dark ambient, about 70.9 μA, compared to that of the as-received photodetector with 13.7 mA. However, it is also highly resistive in nature due to the corresponding electrochemical process selectively dissolute doped regions. Herein, two types of graphene, derived from CVD and the electrochemical exfoliation (EC) process, were cladded onto the porous GaN region. The formation of a graphene/porous GaN interface, as evident from the decrease in average distance between defects as determined from Raman spectroscopy, infers better charge accumulation and conductance, which significantly improved UV sensing. While the leakage current shows little improvement, the UV sensitivity was greatly enhanced, by about 460% and 420% for CVD and EC cladded samples. The slight difference between types of graphene was attributed to the coverage area on porous GaN, where CVD-grown graphene tends to be continuous while EC-graphene relies on aggregation to form films.