Cumulative Counts Research Articles

Quantification of Bedding Rock Slope Deformation Rate Using Guided Wave Monitoring

The guided wave technique is applied to slope stability monitoring to overcome the high attenuation characteristics of acoustic emission propagation in rock and soil materials. The shear tests of “guided wave meter” (GWM) with different deformation rates were carried out, and the effects of the material and particle size of the coupling medium and the diameter of the waveguide rod on the flexural guided wave ring down count were studied, and the relationship between the deformation rate of the slope and the flexural guided wave parameters was analyzed. The results show that the flexural guided wave ring down count rate increases with the increase of deformation in the loading process. The GWM filled with quartz sand particles produces more flexural guided wave ring down counts than those filled with gravel particles. From the twelve groups of GWM shear tests, it can be seen that the GWM with the combination of 16 mm waveguide rod and 4–8 mm quartz sand produces the highest cumulative flexural guided wave ring down counts. The combination is used as an optimized GWM. By applying different deformation rates to the optimized GWM, it was found that the flexural guided wave ring down count rate at different deformation rates tended to increase and was distributed in a fan shape. The cumulative flexural guided wave ring down count has an excellent linear correlation with the deformation. The slope of the cumulative ring down count curves and the deformation curves are obtained separately, which shows that the deformation rate has an excellent linear relationship with the slope of the cumulative ring down count curve, and the slope of the cumulative ring down count curve increases with the increase of the deformation rate. It provides theoretical guidance for quantifying the slope deformation rate using the flexural guided waves.

Spatially refined time-varying reproduction numbers of SARS-CoV-2 in Arkansas and Kentucky and their relationship to population size and public health policy, March – November 2020

PurposeTo examine the time-varying reproduction number, Rt, for COVID-19 in Arkansas and Kentucky and investigate the impact of policies and preventative measures on the variability in Rt.MethodsArkansas and Kentucky county-level COVID-19 cumulative case count data (March 6-November 7, 2020) were obtained. Rt was estimated using the R package ‘EpiEstim’, by county, region (Delta, non-Delta, Appalachian, non-Appalachian), and policy measures.ResultsThe Rt was initially high, falling below 1 in May or June depending on the region, before stabilizing around 1 in the later months. The median Rt for Arkansas and Kentucky at the end of the study were 1.15 (95% credible interval [CrI], 1.13, 1.18) and 1.10 (95% CrI, 1.08, 1.12), respectively, and remained above 1 for the non-Appalachian region. Rt decreased when facial coverings were mandated, changing by -10.64% (95% CrI, -10.60%, -10.70%) in Arkansas and -5.93% (95% CrI, -4.31%, -7.65%) in Kentucky. The trends in Rt estimates were mostly associated with the implementation and relaxation of social distancing measures.ConclusionsArkansas and Kentucky maintained a median Rt above 1 during the entire study period. Changes in Rt estimates allow quantitative estimates of potential impact of policies such as facemask mandate.

Social Determinants of Health and Hypertension Control in Adults with Medicaid.

Social determinants of health (SDOH) are associated with cardiovascular disease, but little is known about mechanisms underlying those relationships. We hypothesized that SDOH would be associated with uncontrolled hypertension (HTN) in adults with Medicaid. This was a retrospective analysis of adults in a Medicaid accountable care organization who had HTN diagnoses, received regular care at community health centers, and enrolled in a cohort study between December 2019 and December 2020. Baseline surveys collected demographics and SDOH, including food insecurity, unstable housing, cost-related medication underuse, and financial stress. Blood pressure (BP) measurements over 12 months after survey completion were obtained from the electronic health record. Participants were categorized as: uncontrolled HTN (mean systolic BP ≥ 140 mm Hg and/or mean diastolic BP ≥ 90 mm Hg), controlled HTN, or unknown HTN control (no BP documented). We examined the association of individual and cumulative (count, 0-4) SDOH with uncontrolled HTN and unknown HTN control using multivariable logistic regression adjusting for demographics, smoking, diabetes, and HTN medication. Participants (n = 245) were mean (SD) age 51.3 (8.6) years, 66.1% female, 43.7% Hispanic, 34.3% White, and 18.0% Black. Overall, 58.0% had food insecurity, 38.0% had unstable housing, 29.4% had financial stress, and 20.0% reported cost-related medication underuse. BP was documented for 180 participants; 44 (24.4%) had uncontrolled HTN. In multivariable models, neither individual nor cumulative SDOH were associated with uncontrolled HTN or unknown HTN control. In a Medicaid-insured population receiving care at community health centers, adverse SDOH were prevalent but were not associated with HTN control.

Analysis of the Tiktok (China)'s Traditional Culture Communication Innovation

The Tiktok(China) started early and invested a lot in the field of traditional culture communication, by 2020.5,short videos on traditional culture have exceeded 65 million, with a cumulative play count of more than 16.4 billion times, which is the most impressive performance among all short video platforms.So, it's necessary to sort out and analyze the Tiktok(China)'s traditional cultural communication innovation, and study its content sources, theme types and innovation strategies,so as to bring inspiration to more short video platforms for traditional culture communication.

Modeling and prediction of the third wave of COVID-19 spread in India

Abstract In this work, we proposed a simple SEIHR compartmental model to study and analyse the third wave of COVID-19 in India. In addition to the other features of the disease, we also consider the reinfection of recovered individuals in the model. For the purpose of parameter estimation we separate the infective and deaths classes and plot them against the cumulative counts of infective and deaths from data, respectively. The estimated parameters from these two are used for prediction and further numerical simulations.We note that the infective will keep on growing and only slow down after around three months. We have studied impact of various parameters on our model and observe that the parameters associated with mask usage, screening and the care giving toCOVID-19 patients have significant impact on the prevalence and time taken to slow down the infection.We conclude that better use of mask, effective screening and timely care to infective will reduce infective and can help in disease control. Our numerical simulations can explicitly provide a short term prediction for such time line. Also we note that providing better care facilities will help reducing peak as well as the disease burden of predicted infected cases.

Dynamic Versus Static Modeling of Mortality-Related Benefits of PM2.5 Reductions in the USA and Chile: 1990 to 2050

AbstractEconomic and health benefits assessments of air quality changes often quantify and report changes in deaths at a given point in time. The typical approach uses a method that attributes air pollution-related health impacts to a single year air quality change (or “pulse”). The perspective on benefits from these static pulse analyses can be enhanced by conducting a dynamic population assessment using life tables. Such analyses can provide a richer characterization of health risks across a population over a multiyear time horizon. In this article, we use the life table approach to quantify cumulative counts of reductions in PM-attributable deaths and life-years gained due to overlapping impacts of PM2.5 changes over a multiyear period, using case studies of air quality improvements in the USA and Chile. Our comparison of health risk and economic valuation for the two approaches shows life table analysis can be a valuable adjunct analysis to the pulse approach though both come with their own set of uncertainties and limitations. If applied jointly, they provide a broader characterization of how air quality actions can change populations in terms of life-years lost, life expectancy, and age structure. The value of these metrics is illustrated using case studies with dramatically different air quality reduction trajectories.

Progressive failure characteristics and energy accumulation of granite with a pre-fabricated fracture during conventional triaxial loading

Deformation and failure of rocks under the loading effect is an energy-driven progressive process of damage evolution, and the abrupt energy release from rocks storing strain energy under high geostress conditions is a determinant inducing catastrophic effects. Therefore, studying the progressive fracture mechanism of rocks from the perspectives of energy accumulation and dissipation contributes to prediction and evaluation of catastrophic effects such as a rockburst. Fractured samples with different fracture dip angles were prepared using granite collected from the underground powerhouse (under maximum geostress of about 37.82 MPa) in Shuangjiangkou Hydropower Station in Dadu River Basin in China. By using these samples, the progressive failure characteristics and energy accumulation and evolution in fractured rocks during triaxial loading were studied under different stress conditions. In addition, the functional relationships of the crack initiation strength, damage strength, and peak strength of the fractured granite with the confining pressure and fracture dip angle in the loading process were established. The evolution of volumetric strain upon cracking corresponding to the peak stress with the confining pressure and fracture dip angle was discussed. Furthermore, the research explored the intrinsic relationships between the acoustic emission (AE) events and mechanical characteristics of the fractured granite during fracturing thereof. The correspondence of the AE count rate and cumulative energy count with various stages in the progressive failure of the rock was studied, and the evolution of the elastic strain energy and dissipated energy in the rock can be predicted based on the strength, deformation, and AE characteristics. Besides, effects of the confining pressure and the dip angle on the AE characteristic signals were investigated. Finally, the accumulation and evolution of the input energy, elastic strain energy, and dissipated energy of fractured granite in the pre-peak stage during triaxial loading were revealed using an energy analysis. Moreover, the relationships of the eigenvalues of elastic strain energy and dissipated energy of fractured granite with the confining pressure and fracture dip angle were determined.

Misspecified modeling of subsequent waves during COVID-19 outbreak: A change-point growth model.

In the analysis of cumulative counts of SARS-CoV-2 infections, such as deaths or cases, common parametric models based on log-logistic growth curves adapt well to describe a single wave at a time. Unfortunately, in Italy, as well as all over the globe, from February 2020 to March 2021 more than one wave has been observed. In this paper, we propose a method to fit more than one wave in the same model. In particular, we discuss an approach based on a change-point model in a pseudo-likelihood framework that takes into account some model misspecification issues, such as those concerning the assumption of Poisson marginals and those relating to overdispersion and autocorrelation. An application to data collected in Italy is discussed.

Predictive Modeling Identifies Total Bleeds at 12-Weeks Postswitch to N8-GP Prophylaxis as a Predictor of Treatment Response.

Background Predicting annualized bleeding rate (ABR) during factor VIII (FVIII) prophylaxis for severe hemophilia A (SHA) is important for long-term outcomes. This study used supervised machine learning-based predictive modeling to identify predictors of long-term ABR during prophylaxis with an extended half-life FVIII. Methods Data were from 166 SHA patients who received N8-GP prophylaxis (50 IU/kg every 4 days) in the pathfinder 2 study. Predictive models were developed to identify variables associated with an ABR of ≤1 versus >1 during the trial's main phase (median follow-up of 469 days). Model performance was assessed using area under the receiver operator characteristic curve (AUROC). Pre-N8-GP prophylaxis models learned from data collected at baseline; post-N8-GP prophylaxis models learned from data collected up to 12-weeks postswitch to N8-GP, and predicted ABR at the end of the outcome period (final year of treatment in the main phase). Results The predictive model using baseline variables had moderate performance (AUROC = 0.64) for predicting observed ABR. The most performant model used data collected at 12-weeks postswitch (AUROC = 0.79) with cumulative bleed count up to 12 weeks as the most informative variable, followed by baseline von Willebrand factor and mean FVIII at 30 minutes postdose. Univariate cumulative bleed count at 12 weeks performed equally well to the 12-weeks postswitch model (AUROC = 0.75). Pharmacokinetic measures were indicative, but not essential, to predict ABR. Conclusion Cumulative bleed count up to 12-weeks postswitch was as informative as the 12-week post-switch predictive model for predicting long-term ABR, supporting alterations in prophylaxis based on treatment response.

Mechanical properties and rockburst proneness of phyllite under uniaxial compression

To investigate the influence of the bedding angle, β,on the mechanical properties and rockburst proneness, uniaxial compression tests were conducted using cylindrical phyllite specimens with different bedding angles. According to the results, the peak stress, peak strain, cumulative acoustic emission counts, and potential energy of the elastic strain exhibited a U-shaped change trend. With an increase in β from 0° to 90°, the failure mode transformed from tensile splitting failure along the bedding plane to shear slip failure along the weak bedding plane. Finally, the failure mode evolved into a tensile splitting failure across the bedding plane. When β=15°, 30°, and 45°, the phyllite specimens exhibited strong, slight, and moderate rockburst proneness, with strong, slight, and moderate shear slip rockbursts, respectively. When β=0°, 60°, 75°, and 90°, the phyllite specimens had extremely strong rockburst proneness, and an extremely strong strain rockburst occurred.

Risk of severe illness from COVID‐19 among Aboriginal and Torres Strait Islander adults: the construct of ‘vulnerable populations’ obscures the root causes of health inequities

ObjectiveTo quantify the prevalence of known health‐related risk factors for severe COVID‐19 illness among Aboriginal and Torres Strait Islander adults, and their relationship with social determinants. MethodsWeighted cross‐sectional analysis of the 2018‐19 National Aboriginal and Torres Strait Islander Health Survey; Odds Ratios for cumulative risk count category (0, 1, or ≥2 health‐related risk factors) by social factors calculated using ordered logistic regression. ResultsOf the adult population, 42.9%(95%CI:40.6,45.2) had none of the examined health‐related risk factors; 38.9%(36.6,41.1) had 1, and 18.2%(16.7,19.7) had ≥2. Adults experiencing relative advantage across social indicators had significantly lower cumulative risk counts, with 30‐70% lower odds of being in a higher risk category. ConclusionsAboriginal and Torres Strait Islander peoples must continue to be recognised as a priority population in all stages of pandemic preparedness and response as they have disproportionate exposure to social factors associated with risk of severe COVID‐19 illness. Indigeneity itself is not a ‘risk’ factor and must be viewed in the wider context of inequities that impact health Implications for public healthMulti‐sectoral responses are required to improve health during and after the COVID‐19 pandemic that: enable self‐determination; improve incomes, safety, food security and culturally‐safe healthcare; and address discrimination and trauma.

Adverse Childhood Experiences and Risk Factors Associated With Asthma Among Children in the United States: The Intersection of Sex and Race/Ethnicity

To evaluate the association between adverse childhood experiences (ACEs) and childhood asthma. In the study, the researchers also examined the effect of race and ethnicity and sex on asthma in pediatric patients.In the study, researchers included 49 000 children between the ages of 0 and 17 years. Within the population, 51.1% were male, and 11.5% had asthma.ACEs were identified from parental report in the 2017–2018 National Survey of Children’s Health. Examples of ACEs included exposure to poverty, parental separation, parental death, incarceration, domestic abuse, neighborhood violence, alcohol and drug use, mental illness, and discrimination. The subjects were separated into 4 groups on the basis of cumulative ACE count: 0, 1, 2, and ≥3. The outcome variable was childhood asthma on the basis of parental report in the National Survey of Children’s Health. The association between ACEs and childhood asthma was examined while adjusting for confounding variables.On the basis of parental report, 42% of children with asthma had at least 1 ACE, with 9.7% having ≥3 ACEs. Compared with children without ACEs, children exposed to ≥3 ACEs had an increased odds of having asthma (adjusted odds ratio [aOR]:1.45; 95% CI: 1.15 to 1.83). In addition, non-Hispanic Black boys (aOR: 1.84; 95% CI: 1.43 to 2.36) and non-Hispanic Black girls (aOR: 1.38, 95% CI: 1.08–1.77) had increased odds of childhood asthma, when compared with non-Hispanic White boys.In the study, the researchers identified an association between ACEs and childhood asthma, especially in children with cumulative ACE exposure (≥3 ACEs).ACEs can lead to short-term and long-term health consequences. In this study, the authors establish a link between ACE exposure and childhood asthma. Better understanding of these interactions could reduce health disparities by facilitating early recognition of children at high-risk for developing asthma. In this study, the authors highlight the need for additional research to understand the biological mechanisms linking ACEs to asthma development.

Multiple viruses detected in human DNA are associated with Alzheimer disease risk.

Multiple infectious agents, including viruses, bacteria, fungi, and protozoa, have been linked to Alzheimer disease (AD) by independent lines of evidence. We quantified DNA sequence reads that align to viral and bacterial reference sequences present in whole exome (WES, N= 15,125) and whole genome (WGS, N= 4,443) sequences measured in blood (N=17,817) and brain (N=1,751) tissue from non-Hispanic white, African American and Caribbean Hispanic participants of the AD Sequencing Project including 9,380 AD cases and 10,188 controls. We tested the association of individual and cumulative normalized viral read counts with AD using logistic and LASSO regression models adjusting for tissue source, sequencing site, sex, APOE genotype, and population. Additional models were tested in subsets stratified by WES/WGS and tissue source. We used PathSeq, a software tool that performs subtraction on high-throughput sequencing data, to identify inserted microbial DNA and tested those species for association with AD. We detected sequences from 175 unique species of human viruses and 17,219 bacteria. Many individual and the cumulative viral read counts varied significantly by sequence center, tissue source, sex, and ancestry. Cumulative normalized human viral read count was associated with AD in every subset of the data (ORmeta = 1.05 per 100,000 units, Pmeta < 7.81x10-12 ). In the WES dataset, the presence of inserted herpes virus 6A sequence measured by PathSeq was protective against AD (OR=0.41, P=0.0007). We also found significant associations using LASSO. In the WES dataset, Hepatitis C was associated with increased AD risk. Herpes 6B was associated with decreased AD risk in both the WES and WGS datasets. In brain samples, herpes 4 and 6B were negatively associated with AD in both WES and WGS datasets, whereas herpes 8 was positively associated with AD and human herpes 3 was negatively associated in the WES dataset. No bacterial species were significantly associated with AD. These results are consistent with the hypothesis that viral infections contribute to AD pathogenesis and highlight the utility of next generation sequencing to detect microbial agents in multiple tissues. Contrary to previous results, except for human herpes 8, herpes viral DNA species are protective against AD.

Abstract 14264: National Comparison of Hospital Market Share for Out-of-Hospital Cardiac Arrest and Elective Cardiac Surgery

Introduction: Competition in the healthcare market is a theoretical driver of innovation, cost-savings, and improved quality. When patients are treated for certain emergent conditions, such as out-of-hospital cardiac arrest (OHCA), individuals have less choice in their treating hospital. For patients undergoing elective cardiac valve replacement surgery (EVRS), hospital choice may reflect distinct referral patterns and preferences. Our objective was to compare hospital market share for different cardiac services, thus allowing for better understanding of the care landscape and target interventions to improve outcomes. Methods: Using age-eligible Medicare fee-for-service institutional claims, an emergency department (ED) treated OHCA cohort was identified via ICD-9/10 diagnosis codes and ED charges. EVRS, an inpatient referral procedure, were identified from in-patient summary claims using procedure codes. Market shares were built for each hospital by sequential addition of ZIP-code areas and calculating the hospital’s cumulative market share. Geographic market share areas were defined for each hospital at 90%, 25% and 10% cut-offs if present. Correlation between corresponding market shares and patient counts were assessed using Pearson’s r. Results: Between 1/2013 and 12/2015, we identified 206,162 EVRS claims and 222,018 OHCA claims. Median age was similar (77 vs 78 yrs), as was percent of female patient (43% vs 44%). Very few beneficiaries (0.38%) appeared in both cohorts. Many more hospitals cared for OHCA than EVRS (4482 vs 1170). More OHCA treating hospitals achieved a 25% market share (68% vs 57%) however, EVRS hospital with a 25% market share covered more population (420,294 vs 66,394) and had a greater client radius (21 vs 15 miles). Among the hospitals providing care to both cohorts, the cumulative market share and patient counts were positively correlated (r = 0.49 and 0.46 respectively, p&lt;0.001 for both). Conclusion: Despite many more hospitals providing care for OHCA, the market share for EVRS and OHCA trend together. This market trend, combined with the association of better outcomes with higher OHCA volume suggests that OHCA should be regionalized within markets to facilities that provide elective cardiac surgical procedures.

The Diversity Patterns of Rare to Abundant Microbial Eukaryotes Across a Broad Range of Salinities in a Solar Saltern

Solar salterns are excellent artificial systems for examining species diversity and succession along salinity gradients. Here, the eukaryotic community in surface water of a Korean solar saltern (30 to 380 practical salinity units) was investigated from April 2019 to October 2020 using Illumina sequencing targeting the V4 and V9 regions of 18S rDNA. A total of 926 operational taxonomic units (OTUs) and 1,999 OTUs were obtained with the V4 and V9 regions, respectively. Notably, most of the OTUs were microbial eukaryotes, and the high-abundance groups (> 5% relative abundance (RA), Alveolata, Stramenopila, Archaeplastida, and Opisthokonta) usually accounted for > 90% of the total cumulative read counts and > 80% of all OTUs. Moreover, the high-abundance Alveolata (larger forms) and Stramenopila (smaller forms) groups displayed a significant inverse relationship, probably due to predator–prey interactions. Most of the low-abundance (0.1–5% RA) and rare (< 0.1% RA) groups remained small portion during the field surveys. Taxonomic novelty (at < 90% sequence identity) was high in the Amoebozoa, Cryptista, Haptista, Rhizaria, and Stramenopila groups (69.8% of all novel OTUs), suggesting the presence of a large number of hidden species in hypersaline environments. Remarkably, the high-abundance groups had little overlap with the other groups, implying the weakness of rare-to-prevalent community dynamics. The low-abundance Discoba group alone temporarily became the high-abundance group, suggesting that it is an opportunistic group. Overall, the composition and diversity of the eukaryotic community in hypersaline environments may be persistently stabilized, despite diverse disturbance events.

Late effects of cancer in children, teenagers and young adults: Population-based study on the burden of 183 conditions, in-patient and critical care admissions and years of life lost.

SummaryBackgroundChildren, teenagers and young adults who survived cancer are prone to developing late effects. The burden of late effects across a large number of conditions, in-patient hospitalisation and critical care admissions have not been described using a population-based dataset. We aim to systematically quantify the cumulative burden of late effects across all cancer subtypes, treatment modalities and chemotherapy drug classes.MethodsWe employed primary care records linked to hospitals, the death registry and cancer registry from 1998–2020. CTYA survivors were 25 years or younger at the time of cancer diagnosis had survived ≥5 years post-diagnosis. Year-of-birth and sex-matched community controls were used for comparison. We considered nine treatment types, nine chemotherapy classes and 183 physical and mental health late effects. Cumulative burden was estimated using mean cumulative count, which considers recurring events. Multivariable logistic regression was used to investigate the association between treatment exposures and late effects. Excess years of life lost (YLL) attributable to late effects were estimated.FindingsAmong 4,063 patients diagnosed with cancer, 3,466 survived ≥ 5 years (85%); 13,517 matched controls were identified. The cumulative burden of late effects at age 35 was the highest in survivors of leukaemia (23.52 per individual [95% CI:19.85–29.33]) and lowest in survivors of germ cell tumours (CI:6.04 [5.32–6.91]). In controls, the cumulative burden was 3.99 (CI:3.93–4.08) at age 35 years. When survivors reach age 45, the cumulative burden for immunological conditions and infections was the highest (3.27 [CI:3.01–3.58]), followed by cardiovascular conditions (3.08 [CI:1.98–3.29]). Survivors who received chemotherapy and radiotherapy had the highest disease burden compared to those who received surgery only. These patients also had the highest burden of hospitalisation (by age 45: 10.43 [CI:8.27–11.95]). Survivors who received antimetabolite chemotherapy had the highest disease and hospitalisation burden, while the lowest burden is observed in those receiving antitumour antibiotics. Regression analyses revealed that survivors who received only surgery had lower odds of developing cardiovascular (adjusted odds ratio 0.73 [CI:0.56–0.94]), haematological (aOR 0.51 [CI:0.37–0.70]), immunology and infection (aOR 0.84 [CI:0.71–0.99]) and renal (aOR 0.51 [CI:0.39–0.66]) late effects. By contrast, the opposite trend was observed in survivors who received chemo-radiotherapy. High antimetabolite chemotherapy cumulative dose was associated with increased risks of subsequent cancer (aOR 2.32 [CI:1.06–4.84]), metastatic cancer (aOR 4.44 [CI:1.29–11.66]) and renal (aOR 3.48 [CI:1.36–7.86]) conditions. Patients who received radiation dose of ≥50 Gy experienced higher risks of developing metastatic cancer (aOR 5.51 [CI:2.21–11.86]), cancer (aOR 3.77 [CI:2.22–6.34]), haematological (aOR 3.43 [CI:1.54–6.83]) and neurological (aOR 3.24 [CI:1.78–5.66]) conditions. Similar trends were observed in survivors who received more than three teletherapy fields. Cumulative burden analyses on 183 conditions separately revealed varying dominance of different late effects across cancer types, socioeconomic deprivation and treatment modalities. Late effects are associated with excess YLL (i.e., the difference in YLL between survivors with or without late effects), which was the most pronounced among survivors with haematological comorbidities.InterpretationTo our knowledge, this is the first study to dissect and quantify the importance of late morbidities on subsequent survival using linked electronic health records from multiple settings. The burden of late effects is heterogeneous, as is the risk of premature mortality associated with late effects. We provide an extensive knowledgebase to help inform treatment decisions at the point of diagnosis, future interventional trials and late-effects screening centred on the holistic needs of this vulnerable population.

Influence of loading rate on failure property of concrete twin fibers pull-out test

Under the premise of considering the mesoscopic heterogeneity of each phase material, we use the dynamic finite element analysis software RFPA^3D-dynamics to establish a three-dimensional dynamic numerical model of concrete twin fibers pull-out test and study the effect of different loading rates on fracture performance of concrete twin fibers pull-out specimens. Based on the elastic damage constitutive relation of mesoscopic elements, the failure diagram of the whole process, distribution curve of interfacial shear stress, acoustic emission (AE) histogram, accumulative AE curves and AE energy analysis of each specimen have been obtained. The results show that the fracture process of concrete twin fibers pull-out specimens under different loading rates goes through the following stages: elastic stage, elastic-plastic damage stage, interface debonding stage and steel fiber pull-out stage. The higher the loading rate, the faster the crack propagation and the interfacial shear stress transmission, and the higher the cumulative acoustic emission counts and the total acoustic emission energy.

Modeling and optimal control of dengue disease with screening and information

This study presents a mathematical model for dengue transmission which quantifies two very important aspects: one, the impact of information-based behavioural response, and the other, the segregation of infected human population into two subclasses, ‘detected’ and ‘undetected’. For the proposed model, the sensitivity analysis is conducted to identify the key model parameters which not only influence the basic reproduction number, but also regulate the transmission of dengue. Further, in order to find the optimal pathways for suitable control interventions that reduce the dengue prevalence and economic burden, an optimal control problem is proposed by considering information-induced behavioural change, quarantine, screening, use of repulsive measures and culling of mosquitoes as control interventions. A weighted sum of various costs incurred in applied controls and the cost due to dengue disease (productivity loss) is incorporated in the proposed cost functional. The analysis of control system using Pontryagin’s maximum principle leads the existence of the optimal control profiles. Further, an exhaustive comparative study for seven different control strategies is conducted numerically. Our findings emphasize that every individual control strategy has their own impact on reducing the cumulative count of infection as well as cost. The combined impact of all control interventions is highly effective and economically viable in controlling the prevalence of dengue. We also investigated the effect of the basic reproduction number on the designed control strategies and observed that the comprehensive use of controls keeps a strong tab on the infective even if the severity of epidemic is high.

Overdensities of submillimetre-bright sources around candidate protocluster cores selected from the South Pole Telescope survey

ABSTRACT We present APEX-LABOCA 870-μm observations of the fields surrounding the nine brightest high-redshift unlensed objects discovered in the South Pole Telescope’s (SPT) 2500 deg2 survey. Initially seen as point sources by SPT’s 1-arcmin beam, the 19-arcsec resolution of our new data enables us to deblend these objects and search for submillimetre (submm) sources in the surrounding fields. We find a total of 98 sources above a threshold of 3.7σ in the observed area of 1300 arcmin2, where the bright central cores resolve into multiple components. After applying a radial cut to our LABOCA sources to achieve uniform sensitivity and angular size across each of the nine fields, we compute the cumulative and differential number counts and compare them to estimates of the background, finding a significant overdensity of $\delta \, {\approx }\,$10 at $S_{870}= 14$ mJy. The large overdensities of bright submm sources surrounding these fields suggest that they could be candidate protoclusters undergoing massive star formation events. Photometric and spectroscopic redshifts of the unlensed central objects range from $z= $3 to 7, implying a volume density of star-forming protoclusters of approximately 0.1 Gpc−3. If the surrounding submm sources in these fields are at the same redshifts as the central objects, then the total star formation rates of these candidate protoclusters reach 10 000 M⊙ yr−1, making them much more active at these redshifts than seen so far in either simulations or observations.

Study on Acoustic Emission Characteristics and Damage Evolution Law of Red Sandstones under Different Loading Rates

Uniaxial compression experiments with different loading rates and acoustic emission tests were conducted to study the loading rate effects on the mechanical and acoustic emission characteristics of red sandstones. The mechanical and acoustic emission parameters of red sandstones were analyzed with varying loading rates. Furthermore, the red sandstone damage evolution model was established based on the acoustic emission cumulative ringing count. The results show that: (1) The elastic modulus decreases linearly with the increase of the logarithm of loading rate, while the peak strength generally shows a gradually increasing trend with the logarithm of the loading rate. (2) With the increase of loading rate, the AE event rate’s peak value increases gradually, and the cumulative number of AE events decreases. (3) The evolution law of the characteristic stresses determined by the AE event rate and cumulative AE event number is the same as that of the loading rate. That is, with the increase of the loading rate, it shows a gradually decreasing evolution trend. (4) The damage evolution model of red sandstone can better describe the damage evolution process of red sandstone. According to the evolution characteristics of damage variables, the damage evolution process of red sandstone can be divided into three stages: the initial damage stage, the damage stable development stage, and the damage accelerated stage. (5) The damage variable at the damage stress point can reflect the actual damage degree of rock, and the size of the damage variable is closely related to the initiation, propagation, and transfixion of microcracks inside the rock. When the loading rate is low, the damage degree of red sandstone at the damage stress is usually more prominent because the rock’s microcrack develops more fully.