Predominant Period Research Articles

Progress in Seismic Isolation Technology Research in Soft Soil Sites: A Review

Soft soil sites can amplify the peak acceleration by a factor of 1.5 to 3.5 and exhibit the filtering effect on seismic waves. This effect results in the attenuation of high frequencies, amplification of low frequencies, and extension of the predominant period of ground motion. Consequently, soft soil sites have a more pronounced impact on isolation buildings constructed on them. The seismic isolation structure design typically involves assuming rigid foundation for calculations. However, the soil properties can significantly impact the dynamic response of the structure, affecting factors such as input ground motion, changes in vibration characteristics, radiation energy dissipation, and material damping energy dissipation. Therefore, neglecting these influences and relying solely on the rigid foundation assumption for calculations can lead to significant errors in the final seismic response analysis of the structure. Currently, there are numerous LNG storage tanks, museums, and other isolation buildings constructed on soft soil sites. Therefore, research on seismic isolation measures for soft soil sites holds significant practical importance. In light of this, this paper, firstly, provides a systematic summary of seismic isolation strategies and engineering applications for soft soil sites. Secondly, it further discusses advancements in research on the dynamic interactions of soil–isolated structures, covering analytical methods, numerical investigations, and experimental studies on soft soil sites. Lastly, the paper concludes with insights on current research progress and prospects for further studies.

Seismic response of a model soil-pile-bridge system in cohesive soil

This paper investigates the dynamic response of a model pile-soil-bridge system subjected to seismic loading using a finite element model (FEM) developed in OpenSees. The numerical model is validated against shake table test data from a companion experimental study, which tested a piles-bridge model fabricated from organic glass. The bridge model comprised four piers, each supported by two-by-two pile groups, with edge piers featuring 60 × 60 mm rubber pads between the pier and deck. Two earthquake ground motions, El Centro and Tianjin, were applied at three intensity levels. The calculated and measured responses show good agreement. The validated FEM reveals that the El Centro earthquake typically induces higher acceleration and moment responses in structural elements compared to the Tianjin earthquake, while the Tianjin earthquake results in greater displacement responses. These findings highlight the impact of earthquake wave characteristics, such as predominant period, on the bridge system's response. Furthermore, the bending moments at the pier top for edge piers remain relatively consistent across different earthquake motions and intensity levels, indicating the role of rubber pads in mitigating seismic forces in the piers.

Chest CT features and risk factors for patients with Omicron variant pneumonia: a multicenter retrospective clinical study.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) Omicron variant infection has become widespread in China as a result of the alterations in epidemic control and prevention policies. We identified the clinical characteristics and lung computed tomography (CT) imaging characteristics of patients infected during the early stage of the Omicron BA.5 wave in Shanghai to provide a guide to the diagnosis, treatment, and prognosis of infection. Clinical information and lung CT imaging characteristics of patients with Omicron variant infection admitted to three designated hospitals in Shanghai from March to June 2022 were analyzed retrospectively. A total of 958 patients were included in the analysis. Among the patients, 169 (17.64%) had pneumonia confirmed by CT, of whom 70.41% (119/169) had lesions in < 10% of the lung area. Older age, unvaccinated status, and comorbid chronic lung disease, cerebrovascular disease, kidney disease, or Alzheimer`s disease were associated with poor prognosis. In patients with coronavirus disease 2019 (COVID-19) pneumonia, a large lesion size was associated with a poor prognosis. Age ≥ 65 years, unvaccinated status, fever > 5 days, and lymphocyte count < 0.5×109/L were risk factors for pneumonia. Age ≥ 65 years, unvaccinated status, fever > 5 days, and lymphocyte count < 0.5×109/L can be used to identify high-risk individuals who warrant a CT scan to screen for COVID-19 pneumonia, especially during the period of Omicron variant predominance. Concurrently, the importance of immunization should be emphasized to help people withstand the effects of Omicron variant infection.

Comparison of clinical characteristics and severity of COVID-19 with or without viral co-infection in hospitalized children

BackgroundCo-infection with other pathogens can alter the severity and clinical outcomes of viral infections. However, the information regarding viral co-infections in pediatric coronavirus disease 2019 (COVID-19) cases is still limited. MethodsThis is a nationwide, retrospective cohort study using the data from the COVID-19 Registry Japan. The pediatric (<18 years), laboratory confirmed, hospitalized COVID-19 patients in the Omicron variant of concern predominant period (January 2022 to January 2024) were included. Co-infection was investigated by multiplex PCR. We compared clinical characteristics, symptoms, severity, and outcomes between children with and without co-infection. ResultsAmong 245 hospitalized pediatric COVID-19 patients, 78 (31.8 %) had co-infections. The patient backgrounds of the “co-infection” and “SARS-CoV-2 alone” groups were similar, although age distribution was different, with a lower number of patients over 12 years in the co-infection group (n = 2, 2.6 % vs. n = 29, 17.4 %; P < 0.001). Among the patients with co-infection, the most common pathogen was enterovirus/rhinovirus (51.3 %), followed by parainfluenza virus (23.1 %) and adenovirus (12.8 %). Patients with co-infection more commonly had respiratory symptoms, including SpO2 < 96 %, shortness of breath, runny nose, and wheezing. Requirement of non-invasive oxygen support was higher in the co-infection group (n = 27, 34.6 % vs. n = 28, 16.8 %, P = 0.006). By multivariable logistic regression analysis, co-infection and presence of any comorbidity were identified as significant risk factors for necessity of oxygen therapy (odds ratio [95 % confidence interval] 2.44 [1.29–4.63] and 3.99 [2.07–7.82], respectively). ConclusionsViral co-infection may increase the risk of respiratory distress in pediatric COVID-19 patients.

Development of earthquake early warning algorithm magnitude scale for the 2023 Kahramanmaraş earthquake region

On 6 February 2023, Türkiye suffered two major earthquakes with magnitudes of Mw = 7.7 and Mw = 7.6 at 04:17 and 13:24 local time in Pazarcık and Elbistan districts of Kahramanmaraş, which were called as the disaster of the century. On 20 February 2023 at 20:04 local time, another major earthquake with Mw = 6.4 occurred in Yayladağı, Hatay. This disaster caused great loss of life and heavy destruction. The burden of the earthquake on the Turkish economy is extremely heavy. The purpose of earthquake early warning systems (EEWS) is to protect people and property, save time for precautions to be taken and prepare emergency response teams. An effective EEWS has a major role in reducing life, structural and economic losses. This study is an implementation of the original California optimized EPIC, an early warning algorithm, in the region of the 2023 Kahramanmaraş earthquakes. A total of 212 earthquakes in the region are replayed to derive magnitude scaling equations based on peak displacement amplitude (Pd) and predominant period (Tpmax). The performance of the modified equations is tested for three large earthquakes. By comparing the magnitudes estimated by Pd and Tpmax, it is observed that Pd gives more suitable results. The 2023 Kahramanmaras earthquakes real-time tests suggested a warning time of 32 s for the first earthquake in Antakya (Hatay), where the heaviest destruction and loss of life was observed. In the other earthquakes, the warning times were interpreted as quite useful to minimize the loss of life. The geography of the 2023 Kahramanmaraş earthquakes is a seismically active region and will be subject to earthquakes in the future. As a result of this study, a region-specific scaling of the magnitude, which is the most important parameter if an early warning system is established in the region, is presented. It is also a good example of how an effective earthquake early warning system can reduce potential hazards.

Nirmatrelvir/ritonavir treatment and the risk of post-COVID condition over 180 days in Malaysia

BackgroundThe effect of nirmatrelvir/ritonavir on preventing post-COVID condition (PCC) in the BA4, BA5, and XBB Omicron predominant periods is not well understood. The purpose of this study was to assess how nirmatrelvir/ritonavir treatment affected both PCC and health-related quality of life.MethodsThis retrospective cohort study enrolled 2,524 adults aged 18 years and older who were eligible for nirmatrelvir/ritonavir between July 14 to November 14, 2022. All outcomes were observed from the patient’s first visit to the primary health clinic, 1 week, 1 month, 3 months, and 6 months after testing positive for COVID-19. The primary outcome was the presence of PCC. Secondary outcomes included the effects on health-related quality of life, such as walking, bathing and dressing, activities, cause adverse emotions or signs that prevent individuals from leading normal lives over a 180-day observation period.ResultsThere were no significant differences observed between the nirmatrelvir/ritonavir and those not administered (control group) in terms of PCC symptoms at 3 months (OR 0.71 95% CI 0.31, 1.64) and 6 months (OR 1.30 95% CI 0.76, 2.21). At 3 months, the use of nirmatrelvir/ritonavir was associated with a 26% reduction in symptoms causing negative emotions (OR 0.74 95% CI 0.60, 0.92) and an increased likelihood of symptoms limiting walking (OR 1.58 95% CI 1.10, 2.27). However, there were no significant differences between the nirmatrelvir/ritonavir and the control group in terms of the impact of PCC on health-related quality of life at 6 months.ConclusionsOur study indicates that the administration of nirmatrelvir/ritonavir does not significantly reduce PCC after 3 months and 6 months in a population with high vaccination coverage.

Prediction and sensitivity analysis of embankment dam settlement under earthquake loading using gene expression programming

ABSTRACT A correct understanding of dams’ dynamic behaviour can help improve structures’ design and safety. The settlement of earth dams caused by earthquake shaking can induce instability and destruction. Using white-box machine learning techniques, including gene expression programming (GEP), a numerical relationship has been tried to estimate the settlement of earth dams under different types of earthquake loading, so that this relationship can be used in the design of earth dams. The main input parameters used in this research include the ratio of the yield acceleration of the dam to the maximum horizontal acceleration of the earthquake (ay/amax), the ratio of the fundamental period of the dam to the predominant period of the earthquake (Td/Tp), the magnitude of the earthquake (Mw) and the settlement ratio (S/H) earth dam as the output parameter. The R, MAE, and RMSE values for the proposed relationship in the research were equal to 0.85, 0.058, and 0.127, respectively. The measurement of statistical parameters shows the acceptable accuracy of the GEP method in predicting S/H. However, developing a database containing other effective parameters can be considered for future research.

Individual risk factors associated with SARS-CoV-2 infection during Alpha variant in high-income countries: a systematic review and meta-analysis.

This study aimed to systematically appraise risk factors associated with SARS-CoV-2 infection in high-income countries during the period of predominance of the Alpha variant (January 2020 to April 2021). Four electronic databases were used to search observational studies. Literature search, study screening, data extraction and quality assessment were conducted by two authors independently. Meta-analyses were conducted for each risk factor, when appropriate. From 12,094 studies, 27 were included. The larger sample size was 17,288,532 participants, more women were included, and the age range was 18-117 years old. Meta-analyses identified men [Odds Ratio (OR): 1.23, 95% Confidence Interval (CI): 1.97-1.42], non-white ethnicity (OR: 1.63, 95% CI: 1.39-1.91), household number (OR: 1.08, 95% CI: 1.06-1.10), diabetes (OR: 1.22, 95% CI: 1.08-1.37), cancer (OR: 0.82, 95% CI: 0.68-0.98), cardiovascular diseases (OR: 0.92, 95% CI: 0.84-1.00), asthma (OR: 0.83, 95% CI: 0.75-0.92) and ischemic heart disease (OR: 0.82, 95% CI: 0.74-0.91) as associated with SARS-CoV-2 infection. This study indicated several risk factors for SARS-CoV-2 infection. Due to the heterogeneity of the studies included, more studies are needed to understand the factors that increase the risk for SARS-CoV-2 infection. https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021244148, PROSPERO registration number, CRD42021244148.

Breakthrough COVID-19 Infections after Booster SARS-CoV-2 Vaccination in a Greek Cohort of People Living with HIV during the Delta and Omicron Waves.

Currently approved SARS-CoV-2 vaccines have been proven effective in protecting against severe COVID-19; however, they show variable efficacy against symptomatic infection and disease transmission. We studied the breakthrough COVID-19 infection (BTI) after booster vaccination against SARS-CoV-2 in people living with HIV (PWH). This was a retrospective, single-center, descriptive cohort study involving PWH, who were followed in the HIV Clinic of "Attikon" University Hospital in Athens, Greece. A BTI was defined as a case of laboratory-confirmed COVID-19 occurring at least 14 days after the third (booster) vaccine dose. We studied 733 PWH [males: 89%, mean age: 45.2 ± 11.3 years, mean BMI: 26.1 ± 4.1, HIV stage at diagnosis (CDC classification): A/B/C = 80/9/11%, MSM: 72.6%] with well-controlled HIV infection. At least one comorbidity was recorded in 54% of cases. A history of ≥1 vaccination was reported by 90%, with 75% having been vaccinated with ≥3 vaccines. Four hundred and two (55%) PWH had a history of COVID-19 and 302 (41.2%) had a BTI, with only 15 (3.7%) needing hospitalization. Only one patient was admitted to the ICU, and no death was reported. Regarding BTI after booster dose, increased age (OR = 0.97, 95% CI: 0.96-0.99, per 1-year increase), and COVID-19 infection prior to booster dose (OR = 0.38, 95% CI: 0.21-0.68) were associated with a lower likelihood for BTI, whereas higher BMI (OR = 1.04, 95% CI: 1.01-1.08) and MSM as a mode of HIV transmission were associated with increased risk (OR = 2.59, 95% CI: 1.47-4.56). The incidence rate of total COVID-19 and BTI followed the epidemic curve of the general population, with the highest incidence recorded in June 2022. A significant proportion of PWH with well-controlled HIV infection experienced a BTI, with the majority of them having mild infection. These data, which include the period of Omicron variant predominance, confirm the importance of vaccination in the protection against severe COVID-19.

Exploring the relationship between vaccine hesitancy and mothers' perspectives on COVID-19 vaccines for children ages 5-11 years during the omicron predominant period 2021-2022: a qualitative study.

The United States Food and Drug Administration authorized COVID-19 vaccines for children ages 5-11 years in October 2021 during the Omicron predominant period. Parental vaccine hesitancy was prevalent during this time, resulting in low childhood COVID-19 vaccine uptake. Most studies exploring factors influencing parental vaccine hesitancy have focused on racial and ethnic minorities and lower socioeconomic populations; however, there is little knowledge of the drive drivers of vaccine hesitancy among White parents with higher education and socioeconomic statuses. We conducted semi-structured interviews with a sample of 15 White mothers of children ages 5-11 years in Atlanta, GA, between October-December 2021. Thematic analysis was performed using NVivo 12. Mothers were college-educated, homeowners, and fully vaccinated against COVID-19. Key findings included decreased pediatrician's recommendations for COVID-19 vaccines, reliance on information from specialized doctors and scientists, distrust in public health authorities, high risk-perception of COVID-19 vaccines, and low risk-perception of COVID-19 disease. Factors related to vaccine acceptance were altruism and practicality. This study adds to the sparse literature on reasons for vaccine hesitancy among White mothers of children ages 5-11 years with higher educational and socioeconomic status. Improving vaccine uptake among this group is critical for protecting the health of their children and other vulnerable populations. Tailored vaccine messaging and intervention are warranted to address their unique attitudes, beliefs, and behaviors. An enhanced understanding of the factors influencing subpopulations of parents can help vaccine policymakers and healthcare providers improve efforts to reduce vaccine hesitancy, particularly for new vaccines.

Seizure Incidence among Children Hospitalized with COVID-19 during the Omicron Wave

Purpose: Since late 2019, coronavirus disease 2019 (COVID-19) has rapidly spread worldwide. Some children with COVID-19 present with seizures; in particular, studies have reported an increase in seizure episodes during the Omicron wave of the pandemic. This study was performed to describe the clinical characteristics of seizures among children hospitalized with COVID-19 before and during the Omicron wave.Methods: A retrospective cross-sectional study was conducted on all pediatric admissions for COVID-19 at Hospital Tunku Azizah from June 2021 to May 2022.Results: During this period, 1,586 children were admitted with COVID-19, of whom 111 (7.0%) experienced seizures. Patients with seizures were more likely to have a history of seizure (odds ratio [OR], 71.4; 95% confidence interval [CI], 23.7 to 215.2; &lt;i&gt;P&lt;/i&gt;&lt;0.001) and prior antiseizure medication use (OR, 55.1; 95% CI, 6.1 to 497.4; &lt;i&gt;P&lt;/i&gt;&lt;0.001). Most seizures (55.0%) occurred on the first day of illness, with 86.5% lasting less than 5 minutes. None of the children required intubation or admission to the pediatric intensive care unit, and all were discharged without complications. Between June 2021 and January 2022, the seizure rate varied from 1.3% to 3.4%; however, it increased to 18% in April 2022, coinciding with the period of Omicron variant predominance in Malaysia. Children admitted during the Omicron wave had significantly higher odds of experiencing seizures (OR, 7.89; 95% CI, 2.07 to 13.07; &lt;i&gt;P&lt;/i&gt;&lt;0.001) than children hospitalized prior to this wave.Conclusion: In conclusion, the study revealed a marked increase in seizures associated with pediatric COVID-19 cases during the Omicron wave.

Modes of delivery and indications in women with COVID-19: a regional observational study in Japan

Background During the coronavirus disease (COVID-19) pandemic, caesarean section (CS) has been the preferred deliver method for pregnant women with COVID-19 in order to limit the use of hospital beds and prevent morbidity among healthcare workers. Methods To evaluate delivery methods used during the COVID-19 pandemic as well as the rates of adverse events and healthcare worker morbidity associated with caesarean deliveries. Methods We investigated maternal and neonatal backgrounds, delivery methods, indications and complication rates among pregnant women with COVID-19 from December 2020 to August 2022 in Mie Prefecture, Japan. The predominant mutation period was classified as the pre-Delta, Delta and Omicron epoch. Results Of the 1291 pregnant women with COVID-19, 59 delivered; 23 had a vaginal delivery and 36 underwent CS. Thirteen underwent CS with no medical indications other than mild COVID-19, all during the Omicron epoch. Neonatal complications occurred significantly more often in CS than in vaginal delivery. COVID-19 in healthcare workers was not attributable to the delivery process. Conclusion The number of CS with no medical indications and neonatal complications related to CS increased during the COVID-19 pandemic. Although this study included centres that performed vaginal deliveries during COVID-19, there were no cases of COVID-19 in healthcare workers. It is possible that the number of CS and neonatal complications could have been reduced by establishing a system for vaginal delivery in pregnant women with recent-onset COVID-19, given that there were no cases of COVID-19 among the healthcare workers included in the study.

Comparative effectiveness of the bivalent COVID-19 mRNA vaccines, mRNA1273-222 and BNT162b2, in immunocompromised adults in the US.

e23057 Background: Despite the decline in COVID-19–related hospitalizations and mortality during the period of omicron predominance, immunocompromised individuals, including those with cancer, remain at an increased risk for severe COVID-19 outcomes. A subanalysis of a retrospective observational cohort study assessed the relative vaccine effectiveness (rVE) of 2 previously approved bivalent vaccines targeting the ancestral SARS-CoV-2 and the omicron BA.4/BA.5 variant, mRNA-1273.222 (Moderna, Inc., Cambridge, MA, USA) and BNT162b2 bivalent (Pfizer Inc., New York, NY, USA; BioNTech GmbH, Mainz, Germany), in immunocompromised adults in the United States. Methods: The study used a US electronic health record dataset (Veradigm) linked with medical and pharmacy claims data of adults aged ≥18 years with at least 1 underlying medical condition associated with increased risk of severe COVID-19 who received a dose of mRNA-1273.222 or BNT162b2 bivalent vaccines between August 31, 2022, and February 28, 2023. A subgroup analysis was conducted among an immunocompromised population, encompassing cancer patients, organ or stem cell transplant recipients, individuals with primary immunodeficiency, individuals with HIV, and individuals receiving immunosuppressing medications. Comorbid conditions were based on prior medical encounters in the 365 days before vaccination. The outcomes measured were rVE of the two bivalent mRNA vaccines against COVID-19-related hospitalizations (primary outcome) and outpatient visits (secondary outcome). Follow-up started 7 days after vaccination until May 31, 2023 (end of available claims data). Propensity score weighting was used to adjust for baseline differences between groups. Results: The subanalysis included 427,260 immunocompromised individuals, of which 250,573 (58.6%) were identified as having cancer. In the overall weighted immunocompromised population, 169,509 individuals received mRNA-1273.222, and 257,751 received BNT162b2 bivalent. The adjusted rVEs of mRNA-1273.222 versus BNT162b2 bivalent vaccine against COVID-19–related hospitalizations and outpatient visits were 15.0% (95% CI, 7.2%-22.0%; P&lt; 0.001) and 4.8% (95% CI, 1.8%-7.7%; P= 0.002), respectively. Conclusions: In this study, the mRNA-1273.222 vaccine offered greater protection against COVID-19–related hospitalization compared with the BNT162b2 bivalent vaccine among immunocompromised individuals. This study emphasizes the importance of assessing COVID-19 vaccine formulations and optimizing protection, especially in immunocompromised adults, including those with cancer.

Enhancement of three isolation optimizations by more reliable estimation of seismic action predominant period

As a large base displacement level is the main drawback of the generally very successful seismic isolation technique, latest optimization procedures for the subsystem at base are focused on the control of that displacement. One family of procedures is based on the existence of one predominant frequency in earthquake excitation, which is evident only if the spectral analysis is performed considering displacement as the input, rather than the common ground acceleration. Nevertheless, recent results, besides corroborating the existence of one predominant period, have produced an improvement in the computation of this single spectral parameter. In this paper, this more reliable seismic predominant frequency is employed in previously successful methodologies to control isolator displacement. The hypothesis is that an enhanced model of the input will result in an improved structural response, which again, it is further reduced base displacements.

Structural and non‐structural numerical blind prediction of shaking table experimental tests on fixed‐base and base‐isolated hospitals

AbstractBase‐isolated hospitals are frequently preferred to fixed‐base ones because of their improved seismic structural performance. Despite this, the question remains open on the advisability of using this modern seismic protection technology in preference to other conventional solutions, on the grounds of a holistic approach based on limiting non‐structural damage as well as continuity of service to the community in the aftermath of an earthquake. Two full‐scale four‐storey (fixed‐base) and three‐storey (base‐isolated) hospital buildings have been recently built and subjected to three‐dimensional shaking table tests at the National Research Institute for Earth Science and Disaster Prevention (Japan), with particular attention to evaluating and classifying functionality of non‐structural components and vital medical equipment. A two‐phase experimental campaign was carried out considering two earthquakes scaled at different intensity levels and applied along the horizontal and vertical directions. The current study aims to provide results of a numerical structural and non‐structural blind prediction of these hospital settings. A homemade numerical code is developed to account for lumped plasticity modelling of steel frame members and variability of the friction coefficient of spherical sliding bearings. Moreover, three non‐structural components are modelled in the fixed‐base structure: that is, elastic single degree of freedom systems representing two tanks filled with sand at the top floor; elastic beam elements for piping at the third floor; five‐element macro‐model for the in‐plane‐out‐of‐plane nonlinear response of partition walls at the first floor. The identification of predominant vibration periods of the fixed‐base structure is carried out using a homemade numerical code based on the continuous wavelet transforms in combination with the complex Morlet wavelet. Finally, the sliding and rocking motion of three items of medical equipment (i.e., incubator at third floor, dialysis machine at second floor and surgical bed at first floor) are analysed by means of a homemade numerical code, considering acceleration time histories of selected structural nodes of the fixed‐base structure.

Design and Validation of a Stratified Shear Model Box for Seismic Response of a Sand-Blowing Reclamation Site

The global increase in building collapses and damage on soft-soil sites due to distant significant earthquakes poses similar challenges for sand-blowing reclamation (SBR) sites on soft-soil layers. This study was initiated to capture the vibration characteristics of the SBR sites and to provide fresh insights into their seismic responses. Initially, considering the heterogeneity and layered structure of soil at SBR sites, we developed a novel stratified shearing model box. This model box enables the simulation of the complex characteristics of soil layers at SBR sites under laboratory conditions, representing a significant innovation in this field. Subsequently, an innovative jack loading system was developed to apply active vertical pressure on the soil layer model, accelerating soil consolidation. Furthermore, a new data collection and analysis system was devised to monitor and record acceleration, pore water pressure, and displacement in real time during the experiments. To verify the model box’s accuracy and innovation, and to examine the seismic response of SBR sites under varying consolidation pressures, four vibration tests were conducted across different pressure gradients to analyze the model’s predominant period evolution due to consolidation pressures. The experimental results demonstrate that the model box accurately simulates the propagation of one-dimensional shear waves in soil layers under various consolidation pressures, with notable repeatability and reliability. Our experiments demonstrated that increasing consolidation pressure results in higher shear wave speeds in both sand and soft-soil layers, and shifts the site’s predominant period towards shorter durations. Concurrently, we established the relationship between the site’s predominant period and the input waves. This study opens new paths for further research into the dynamic response properties of SBR sites under diverse conditions through shaking-table tests.

Risk factors for COVID-19 hospitalisation after booster vaccination during the Omicron period: A French nationwide cohort study

BackgroundIn spite of major effectiveness, a residual risk after COVID-19 primary vaccination was identified, in particular, for vulnerable individuals of advanced age or with comorbidities. Less is known about the Omicron period in people protected by a booster dose. We aimed to identify the characteristics associated with severe COVID-19 during the Omicron period in a population that had received a booster dose in France and to compare differences with the previous periods of the pandemic. MethodsThis study was carried out using the French national COVID-19 vaccination database (VAC-SI) coupled with the National Health Data System (SNDS). Individuals aged 12 years or over who received at least one booster dose were identified. Associations between socio-demographic and clinical characteristics and the risk of COVID-19 hospitalisation occurring at least 14 days after receiving a third dose of vaccine during the period of Omicron predominance, i.e., from 1 January 2022 to 10 November 2022, were assessed using Cox proportional hazard models adjusted for age, sex, time since booster dose and vaccination schedule. Analyses were performed overall and by sub-period of circulation of the strains BA.1, BA.2, and BA.4/BA.5, defined as periods where the main sub-variant accounted for more than 80 % of genotyped samples. FindingsIn total, 35,640,387 individuals received a booster dose (mean follow-up of 291 days) and 73,989 were hospitalised for COVID-19 during the total period. Older age (aHR 20.5 95 % CI [19.6–21.5] for 90 years of age or older versus 45–54 years of age), being male (aHR 1.52 [1.50–1.55]), and social deprivation (aHR 1.33 [1.30–1.37] for the most deprived areas versus the least deprived) were associated with an increased risk of hospitalisation for COVID-19. Most of the chronic diseases considered were also positively associated with a residual risk, in particular, cystic fibrosis (aHR 9.83 [7.68–12.56]), active lung cancer (aHR 3.26 [3.06–3.47]), chronic dialysis (aHR 3.79 [3.49–4.11]), psychological and neurodegenerative diseases (more markedly than during the periods of circulation of the alpha and delta variants), and organ transplantation. The use of immunosuppressants was also associated with an increased risk (aHR 2.24 [2.14–2.35], including oral corticosteroids aHR (2.58 [2.50–2.67]). ConclusionDespite an effective booster and a generally less virulent circulating variant, a residual risk of severe COVID-19 still exists in vulnerable populations, especially those with neurological disorders.

Asymmetric Drift Map of the Milky Way Disk Populations between 8 -16 kpc with LAMOST and Gaia datasets

The application of asymmetric drift (AD) tomography across different populations provides valuable insights into the kinematics, dynamics, and rotation curves of the Galactic disk. By leveraging common stars identified in both the LAMOST and Gaia surveys, alongside Gaia DR3’s circular velocity curve, we conducted a qualitative exploration of asymmetric drift distributions within the Galactic disk spanning distances from 8 to 16 kpc. In the R-Z plane, we observed that the asymmetric drift is minimal near the mid-plane of the Galactic disk and gradually increases with vertical distance, resulting in a distinctive “horn” shape. Additionally, our analysis revealed that populations with higher [ α/Fe] ratios exhibit greater asymmetric drift compared to those with lower [ α/Fe] ratios. Specifically, we found the asymmetric drift around the solar location to be approximately 6 km s −1, with a median value of 16 km s −1 across the entire sample. Notably, the median asymmetric drift in the northern region of the Galactic disk (20 km s −1) surpasses that in the southern region (13 km s −1), with errors remaining within 2 km s −1. Furthermore, our investigation into mono-age stellar populations unveiled that older stellar populations tend to exhibit larger asymmetric drift and velocity dispersion, aligning closely with predictions from previous numerical models. Finally, based on chemical compositions, we observed that the median asymmetric drift of the thick disk significantly exceeds that of the thin disk and found that star formation within the thick disk primarily occurred 8-10 billion years ago, whereas the thin disk’s predominant star formation period spanned 6-8 billion years ago.

Analyzing factors affecting positivity in drive-through COVID-19 testing: a cross-sectional study

BackgroundDemand for COVID-19 testing prompted the implementation of drive-through testing systems. However, limited research has examined factors influencing testing positivity in this setting.MethodsFrom October 2020 to March 2023, a total of 1,341 patients, along with their clinical information, were referred from local clinics to the Sasebo City COVID-19 drive-through PCR center for testing. Association between clinical information or factors related to the drive-through center and testing results was analyzed by Fisher’s exact test and logistic regression models.ResultsIndividuals testing positive exhibited higher frequencies of upper respiratory symptoms; cough (OR 1.5 (95% CI 1.2–1.8), p < 0.001, q = 0.005), sore throat (OR 2.4 (95% CI 1.9-3.0), p < 0.001, q < 0.001), runny nose (OR 1.4 (95% CI 1.1–1.8), p = 0.002, q = 0.009), and systemic symptoms; fever (OR 1.5 (95% CI 1.1-2.0), p = 0.006, q = 0.02), headache (OR 1.9 (95% CI 1.4–2.5), p < 0.001, q < 0.001), and joint pain (OR 2.7 (95% CI 1.8–4.1), p < 0.001, q < 0.001). Conversely, gastrointestinal symptoms; diarrhea (OR 0.2 (95% CI 0.1–0.4), p < 0.001, q < 0.001) and nausea (OR 0.3 (95% CI 0.1–0.6), p < 0.001, q < 0.001) were less prevalent among positives. During omicron strain predominant period, higher testing positivity rate (OR 20 (95% CI 13–31), p < 0.001) and shorter period from symptom onset to testing (3.2 vs. 6.0 days, p < 0.001) were observed compared to pre-omicron period. Besides symptoms, contact history with infected persons at home (OR 4.5 (95% CI 3.1–6.5), p < 0.001, q < 0.001) and in office or school (OR 2.9 (95% CI 2.1–4.1), p < 0.001, q < 0.001), as well as the number of sample collection experiences by collectors (B 7.2 (95% CI 2.8–12), p = 0.002) were also associated with testing results.ConclusionsThese findings underscore the importance of factors related to drive-through centers, especially contact history interviews and sample collection skills, for achieving higher rates of COVID-19 testing positivity. They also contribute to enhanced preparedness for next infectious disease pandemics.

Optimal earthquake intensity measures for seismic vulnerability assessment of concrete-faced rockfill dams

Earthquake intensity measure (IM) selection is crucial for developing probabilistic seismic demand models (PSDMs). This study explored the optimal IMs that can be utilized in PSDMs for concrete-faced rockfill dams (CFRDs). A two-dimensional nonlinear dynamic analysis of a CFRD was performed to assess its response to earthquake ground motion. A numerical model of CFRD was developed using the commercial software LS-DYNA with an advanced hysteretic soil model. A total of 20 earthquake IMs were selected for regression analysis. The regression analysis was performed between IMs and the damage index (DI). The IMs were evaluated through a selection process based on the goodness of fit as well as their efficiency, practicality, and proficiency. Accordingly, a range of optimal IMs was determined. The results indicated that effective design acceleration (EDA) is the best earthquake IM correlating with the seismic response of dam settlement and can be considered the optimal IM, whereas peak ground displacement (PGD), ratio of peak ground velocity to peak ground acceleration (PGV/PGA), and predominant period (Tp) are the less efficient. The fragility curves and surfaces were developed employing both scalar and vector IMs for CFRD.