Influence of exogenous factors on water demand forecasting models during the COVID-19 period

Water scarcity has urged the need for adequate water demand forecasting to facilitate efficient planning of municipal infrastructure. However, the development of water consumption models is challenged by the rapid environmental and socio-economic changes, particularly during unforeseen events like the COVID-19 pandemic. This study investigated the impact of COVID-19 on the efficiency of water demand prediction models, considering the lockdown measures and various exogenous features, such as previous consumption (PC) and socio-demographic (SDF), seasonal (SF), and climatic (CF) factors. Multiple ensemble models, gradient-boosting machines (GBM), extreme-gradient-boosting (XGB), light-gradient-boosting, random forest (RF), and stack regressor (STK) were examined, compared to other machine-learning techniques, multiple-linear regression (MLR), decision trees, and neural networks. The models were tested using 3-year metering records for 128,000 consumers in Dubai. The feature importance analysis indicated that PC and SDF had a significant impact on consumption rates with correlation coefficients of 0.95 and 0.74, respectively, as opposed to SF and CF, which had negligible effect. The results showed that, before COVID, RF and STK outperformed other models with a coefficient-of-determination (R2) and root-mean-squared-error (RMSE) of 0.928 and 0.039, followed by XGB at 0.923 and 0.041, respectively. However, MLR achieved the highest prediction accuracy amid COVID with R2 and RMSE of 0.90 and 0.05, followed by GBM and XGB equally at 0.83 and 0.06, respectively. An ensemble-based error prediction model was applied, resulting in up to 9.2% improvement in predictions. Overall, this research emphasized the efficiency of ensemble models in handling fluctuating data with a high degree of nonlinearity.

Modeling of corona virus and its application in confocal microscopy

Background The proposal of spiky apertures showed resolution improvement compared with the circular apertures. Three models of corona virus are given. The 1st model consists of uniform circular aperture provided with 8 spikes while the 2nd model has 16 spikes for the same uniform circular aperture. The 3rd model has circular linear distribution with 8 spikes. Results The Normalized Point Spread Function (PSF) or the impulse response is computed for the three models using fast Fourier transform technique. In addition, the autocorrelation function corresponding to these apertures is calculated and compared with that corresponding to the ordinary circular and conic apertures. Coronavirus image is used as an object in the formation of images using confocal scanning laser microscope provided with suggested models. The fabricated MATLAB code is used to compute and plot all images and line plots. Conclusions The PSF plots are computed from Eqs. (8) and (12) using MATLAB code showing narrower cutoff in the PSF for spiky aperture compared with that corresponding to the uniform circular aperture and modulated linear and quadratic apertures. Hence, I reached resolution improvement in the case of spiky aperture.

The Mechanisms of Collective Resilience in a Crisis Context: The Case of The ‘COVID-19’ Crisis

In this research, we claim to join the efforts of practitioners and researchers to provide managerial responses to an unprecedented health crisis such as COVID-19. To do this, we study the concept of 'collective resilience' as a mechanism for responding to crisis in the Tunisian context. The aim of this research is to explain the impact of collective resilience processes on the ability of organizations to withstand crisis. We conducted sixteen semi-structured interviews with Tunisian companies that had experienced the COVID-19 crisis. Continuous analysis of these interviews was carried out with the Nvivo12 software. Our results showed a positive effect of collective resilience on the capacity of organizations to resist the COVID-19 crisis by developing protective factors. These are manifested by new intersubjective interactions (massive exchanges, shared representation, collective consciousness, collaboration, solidarity, mutual aid, etc.), generic interactions (actions and assembly rules not used before: less formalized rules and procedures, more flexible and decentralized structure, new organizational diagrams based on trust, accountability, etc.) and finally the improvisation and tinkering of the organization which made it possible to bring about a change affecting all levels of the organization: strategic and organizational.

Occurrence, human exposure, and risk of microplastics in the indoor environment.

Microplastics (MPs) are a group of emerging contaminants that have attracted increasing scientific and societal attention over the past decade due to their ubiquitous detection in all environmental compartments. So far, most studies on MPs focus on characterizing their occurrence, fate, and impact in the aquatic environment. Therefore, very little is known about the magnitude, patterns, and associated risks of human exposure to MPs, particularly indoors. This is a significant research gap given that people spend most of their time (up to 90%) indoors, which is exacerbated over the past year by COVID-19 lockdown measures. Critical evaluation of the existing literature revealed the presence of MPs at higher concentrations in indoor air and dust (from homes and offices) compared to outdoors. This was attributed to several factors including: indoor MPs sources (e.g. furniture, textiles), increased deposition of atmospheric MPs indoors, and less atmospheric mixing and dilution compared to outdoor air. Current understanding is that indoor human exposure to MPs occurs via a combination of inhalation, ingestion, and dermal contact. Dietary intake was considered the major pathway of human exposure to MPs until recent studies revealed potential high exposure via inhalation. Moreover, exposure via inadvertent dust ingestion and dermal contact cannot be neglected, particularly for young children. This is alarming due to the potential toxic implications of MPs exposure. Early toxicological evidence indicates that small MPs (<20 µm) can cause oxidative stress and inflammation, while particles <5 µm can be engulfed by cells and translocated to accumulate in different organs. Also, there is increasing concern over potential leaching of toxic chemicals used as plastic additives (e.g. plasticizers and flame retardants) upon exposure to MPs due to their large surface area. However, MPs exposure and risk assessment in humans is still in its infancy and more research is necessary to provide the knowledge base required for regulations to protect human health and environment against MPs.

Organizational resilience as response to a crisis: case of COVID-19 crisis

PurposeThe purpose of this paper is to explore the contribution of organizational resilience to the capacity of companies to cope with the COVID-19 crisis in a real organizational context through an empirical study of 16 Tunisian companies affected by the crisis.Design/methodology/approachThe authors adopt a qualitative study based on 16 semi-structured interviews to describe better the functioning of the processes of resilience in a real organizational context.FindingsThe real contribution consists in confirming a positive contribution of resilience to resistance in the face of the COVID-19 crisis in a Tunisian context through exceptional measures that have not previously been adopted by the companies concerned by this study.Originality/valueThe authors believe that they are the first to study the theme of resilience as a resistance mechanism in the face of the COVID-19 crisis in a Tunisian context. From this comes the originality of the research.

The evolving challenges confronting adults living with HIV in three North African countries during the COVID-19 crisis: a survey-based study.

BACKGROUND: Coronavirus disease 2019 (COVID-19) has resulted in a huge burden on healthcare systems, especially on programs for chronic illnesses such as HIV. We aimed to assess the challenges confronting adult people living with HIV (PLHIV) in three countries in North Africa during the COVID-19 crisis and their awareness of COVID-19 non-pharmaceutical preventive measures. METHODS: This online survey included PLHIV aged ≥18 y from three countries in North Africa recruited by a snowball sampling technique, who were asked to complete a modified questionnaire originally developed by the University of Antwerp in Belgium, which was then disseminated through social media tools to assess the study outcomes. RESULTS: Out of 369 respondents, 260 (70.5%) were males and 237 (64.2%) were aged 18-39 y. Adherence to COVID-19 preventive measures, wearing facemasks (308 [83.2%]), applying hand-sanitizers (299 [80.8%]) and following cough etiquette (261 [70.5%]), were predominantly reported. Only 48 (13%) were vaccinated against influenza. One hundred and forty-five participants (42%) experienced flu-like symptoms, 29 (20%) were tested for COVID-19, with only one confirmed case identified. Among 344 (93.2%) on antiretroviral therapy (73.8% efavirenz- vs 6.4% dolutegravir-based regimens), 219 (63.7%) attended their scheduled visits, 144 (41.9%) had limited access to care due to lockdown and 29 (8.4%) became less adherent to their antiretroviral therapy. Covariates associated with challenges during access to care were age ≥60 y (OR=6.5; 95% CI 1.8 to 23.2) and receiving second-line HIV treatment such as protease inhibitors (OR=2.7; 95% CI 1.3 to 5.8). CONCLUSION: The pandemic adversely affected PLHIV. New innovative strategies should be implemented to ensure the continuity of HIV services.

Humoral immunity to SARS-CoV-2 and seasonal coronaviruses in children and adults in north-eastern France.

BACKGROUND: Children are underrepresented in the COVID-19 pandemic and often experience milder disease than adolescents and adults. Reduced severity is possibly due to recent and more frequent seasonal human coronaviruses (HCoV) infections. We assessed the seroprevalence of SARS-CoV-2 and seasonal HCoV specific antibodies in a large cohort in north-eastern France. METHODS: In this cross-sectional seroprevalence study, serum samples were collected from children and adults requiring hospital admission for non-COVID-19 between February and August 2020. Antibody responses to SARS-CoV-2 and seasonal HCoV (229E, HKU1, NL63, OC43) were assessed using a bead-based multiplex assay, Luciferase-Linked ImmunoSorbent Assay, and a pseudotype neutralisation assay. FINDINGS: In 2,408 individuals, seroprevalence of SARS-CoV-2-specific antibodies was 7-8% with three different immunoassays. Antibody levels to seasonal HCoV increased substantially up to the age of 10. Antibody responses in SARS-CoV-2 seropositive individuals were lowest in adults 18-30 years. In SARS-CoV-2 seronegative individuals, we observed cross-reactivity between antibodies to the four HCoV and SARS-CoV-2 Spike. In contrast to other antibodies to SARS-CoV-2, specific antibodies to sub-unit 2 of Spike (S2) in seronegative samples were highest in children. Upon infection with SARS-CoV-2, antibody levels to Spike of betacoronavirus OC43 increased across the whole age spectrum. No SARS-CoV-2 seropositive individuals with low levels of antibodies to seasonal HCoV were observed. INTERPRETATION: Our findings underline significant cross-reactivity between antibodies to SARS-CoV-2 and seasonal HCoV, but provide no significant evidence for cross-protective immunity to SARS-CoV-2 infection due to a recent seasonal HCoV infection. In particular, across all age groups we did not observe SARS-CoV-2 infected individuals with low levels of antibodies to seasonal HCoV. FUNDING: This work was supported by the « URGENCE COVID-19 ¼ fundraising campaign of Institut Pasteur, by the French Government's Investissement d'Avenir program, Laboratoire d'Excellence Integrative Biology of Emerging Infectious Diseases (Grant No. ANR-10-LABX-62-IBEID), and by the REACTing (Research & Action Emerging Infectious Diseases), and by the RECOVER project funded by the European Union's Horizon 2020 research and innovation programme under grant agreement No. 101003589, and by a grant from LabEx IBEID (ANR-10-LABX-62-IBEID).

Pattern and determinants of COVID-19 infection and mortality across countries: An ecological study.

BACKGROUND: This work aimed to identify the mathematical model and ecological determinants of COVID-19 infection and mortality across different countries during the first six months of the pandemic. METHODOLOGY: In this study, authors used the online available data sources of randomly selected 18 countries to figure out potential determinants of COVID-19 transmissibility and mortality. The studied variables were environmental factors (daily average temperature, daily humidity), socioeconomic attributes (population age structure, count and density, human development index, per capita income (PCI), gross domestic product, internet coverage) mobility trends and chronic diseases. Researchers used the linear and exponential time series analysis, and further utilized multivariate techniques to explain the variance in the monthly increase in cases and deaths. RESULTS: In the first two months, the R2 of linear models for the cases and deaths were higher than that of the corresponding R2 of the exponential model. Later one, R2 of the exponential model was occasionally relatively higher than that of the linear model. The exponential growth rate of new cases was significantly associated with mobility trends (ß = 0.00398, P = 0.002), temperature (ß = 0.000679, P = 0.011), humidity (ß = 0.000249, P < 0.001), and the proportion of population aged ≥65 years (ß = -0.000959, P = 0.012). Similarly, the exponential growth rate of deaths was significantly associated with mobility trends (ß = 0.0027, P = 0.049), temperature (ß = 0.0014, P < 0.001), humidity (ß = -0.0026, P < 0.001), and PCI of countries. During this period, COVID-19 transmissibility was evident to be controlled as soon as social mobility is decreased by about 40% of the baseline over 3 months controlling for the other predictors. CONCLUSION: Controlling of COVID-19 pandemic is based mainly on controlling social mobility. Role of environmental determinants like temperature and humidity was well noticed on disease fatality and transmissibility. Socio-demographic determinants of COVID-19 spread and fatality included modifiable risk factors like PCI and non-modifiable risk factors like ageing.

Efficacy of combined Sofosbuvir and Daclatasvir in the treatment of COVID-19 patients with pneumonia: a multicenter Egyptian study.

BACKGROUND: Limited experimental and clinical evidence suggests a potential role for sofosbuvir/daclatasvir in treating COVID19. We aim to evaluate the efficacy of generic sofosbuvir/daclatasvir in treating COVID-19 patients with pneumonia. RESEARCH DESIGN AND METHODS: This multicenter prospective study involved 174 patients with COVID-19. Patients were randomized into two groups. Group A (96 patients) received sofosbuvir (400 mg)/daclatasvir (60 mg) for 14 days in combination with conventional therapy. Group B (78 patients) received conventional therapy alone. Clinical, laboratory, and radiological data were collected at baseline, after 7, 14, and 28 days of therapy. Primary endpoint was rate of clinical/virological cure. RESULTS: A lower mortality rate was observed in group (A) (14% vs 21%, P = 0.07). After 1 month of therapy, no differences were found in rates of ICU admission, oxygen therapy, or ventilation. Additionally, a statistically significant shorter duration of hospital stay (9% vs 12%, P < 0.01) and a faster achievement of PCR negativity at day 14 (84% versus 47%, P < 0.01) were noticed in group (A). CONCLUSION: Adding sofosbuvir/daclatasvir to conventional therapy of COVID-19 is promising. Their use is associated with shorter hospital stay, faster PCR negativity and may be reduced mortality.

Gastrointestinal manifestations of human immunodeficiency virus and coronavirus disease 2019: Understanding the intersecting regions between the two epidemics.

In March 2020, the World Health Organization declared coronavirus disease (COVID-19) a pandemic. As of February 2021, there were 107 million COVID-19 cases worldwide. As a comparison, there are approximately 38 million people living with human immunodeficiency virus (PLHIV) worldwide. The coexistence of both epidemics, and the syndemic effect of both viruses could lead to a delirious impact both at individual and community levels. Many intersecting points were found between severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19, and HIV; among which, gastrointestinal (GI) manifestations are the most notable. GI manifestations represent a common clinical presentation in both HIV and SARS-CoV-2. The emergence of GI symptoms as a result of SARS-CoV-2 infection provides a new dynamic to COVID-19 diagnosis, management, and infection control measures, and adds an additional diagnostic challenge in case of coinfection with HIV. The presence of GI manifestations in PLHIV during the COVID-19 pandemic could be referred to HIV enteropathy, presence of opportunistic infection, adverse effect of antiretrovirals, or coinfection with COVID-19. Thus, it is important to exclude SARS-CoV-2 in patients who present with new-onset GI manifestations, especially in PLHIV, to avoid the risk of disease transmission during endoscopic interventions. Structural similarities between both viruses adds a valuable intersecting point, which has mutual benefits in the management of both viruses. These similarities led to the hypothesis that antiretrovirals such as lopinavir/Rironavir have a role in the management of COVID-19, which was the target of our search strategy using the available evidence. These similarities may also facilitate the development of an efficient HIV vaccine in the future using the advances in COVID-19 vaccine development.

Clinical orthodontic management during the COVID-19 pandemic.

OBJECTIVES: To provide a comprehensive summary of the implications of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and coronavirus disease 2019 (COVID-19) on orthodontic treatment, contingency management, and provision of emergency orthodontic treatment, using currently available data and literature. MATERIALS AND METHODS: Orthodontically relevant sources of information were searched using electronic databases including PubMed and Google Scholar and current reports from major health bodies such as Centers for Disease Control and Prevention, World Health Organization, National Institutes of Health, and major national orthodontic associations. RESULTS: Where available, peer-reviewed and more recent publications were given priority. Due to the rapidly evolving nature of COVID-19 and limitations in quality of evidence, a narrative synthesis was undertaken. Relevant to orthodontics, human-to human transmission of SARS-CoV-2 occurs predominantly through the respiratory tract via droplets, secretions (cough, sneeze), and or direct contact, where the virus enters the mucous membrane of the mouth, nose, and eyes. The virus can remain stable for days on plastic and stainless steel. Most infected persons experience a mild form of disease, but those with advanced age or underlying comorbidities may suffer severe respiratory and multiorgan complications. CONCLUSIONS: During the spread of the COVID-19 pandemic, elective orthodontic treatment should be suspended and resumed only when permitted by federal, provincial, and local health regulatory authorities. Emergency orthodontic treatment can be provided by following a contingency plan founded on effective communication and triage. Treatment advice should be delivered remotely first when possible, and where necessary, in-person treatment can be performed in a well-prepared operatory following the necessary precautions and infection prevention and control (IPAC) protocol.