Age Composition Research Articles

First results of stratigraphic drilling in the North-Eastern Laptev Sea

The Stratigraphic Drilling Project of the Russian Arctic Shelf conducted by the PJSC Rosneft is aimed at discover the stratigraphic age and rock composition of sedimentary succession of its subsurface. In 2021, six shallow wells for the first time have been drilled with core sampling in the east of the Laptev Sea. Drilling revealed folded sedimentary succession dated back to the Late Barremian – Early Aptian. The synrift complex overlying unconformably dates to the Paleocene. The upper strata dates from Eocene to Pleistocene and contains significant hiatuses. The data discovered together with the results of seismic interpretation clarified the regional geological model and dated the stages of its tectonic evolution.

Knee muscle strength, body composition, and balance performance of youth soccer players

BackgroundMuscle strength and balance abilities have been related to game performance injury prevention. This study aimed to (1) assess knee muscle strength performance based on intra- and inter-limb asymmetries, (2) investigate the relationships between knee muscle strength, body composition, and balance, and (3) analyze the variance in the overall stability index (OSI) explained by knee muscle strength indicators after controlling for age and body composition.MethodsThe sample included 104 young male soccer players (16.0 ± 1.6 years). Body composition, knee muscle strength, and balance ability were assessed. A paired samples t-test was used to examine differences between the preferred leg (PL) and the non-preferred leg (NPL). Pearson correlations and hierarchical multiple regression were conducted to explore the relationships between strength, body composition, and balance.ResultsNo significant inter-limb asymmetries were detected for the knee flexors (KF) and knee extensors (KE) performance. The hamstrings-to-quadriceps ratio does not suggest the existence of intra-limb asymmetries (p = 0.06). Significant and negative correlations were found between KF (r = -0.38, p ≤ 0.01) and KE (r = -0.58, p ≤ 0.01) for the PL. Concerning the NPL, KE also revealed a significant and negative relationship with balance (r = -0.30, p ≤ 0.01). Significant and positive relationships were found between bodyweight, fat-free mass, and balance. After controlling for age and body composition, knee muscle strength could explain between 13% and 30% of the variance observed in the OSI (NPL and PL, respectively).ConclusionsThe results underline knee muscle strength as an important predictor of balance. Thus, training programs targeting knee muscle strength development should be considered during the season periodization by coaches and their staff throughout the players’ developmental stages.

Magyarországi helyzetkép az alternatív gondoskodás lehetőségeiről, különös tekintettel a gyermekotthoni, nevelőszülői elhelyezésre

In this study, we compare institutional and foster care. The method chosen is a secondary analysis of statistical data. In the study, we seek to answer the question of how the number of places, the number of children, the age composition of children, the duration of placement and the type of placement vary in Hungary and in the Northern Great Plain region. We analyse data for the years 2014, 2021 and 2023 in terms of deinstitutionalisation and present the current situation of child protection care alongside the trends in institutional restructuring in recent years. A further aim of our comparative analysis is to review the number of cases of runaways from care in recent years, assuming that they occur less frequently in foster care. For the analysis, we have primarily used data for the years 2014, 2021 and 2023. In some places, the year 2020 was analysed due to data availability. We have used publicly available data series from the KSH, as well as data recorded on the basis of individual data requests according to the KSH OSAP Form 1208, which contains data provided by child protection centres based in the respective counties.

Dynamics of the age composition of the red king crab males in the Barents Sea with account of probability molt

The aim of the research was improvement of the algorithm of age determination for red king crab males in the Barents Sea, by taking into account the molting probability.Materials were the data of research surveys and fisheries monitoring obtained in 2001–2022 and combined in 54 data sets, as well tagging data published in open press.As results the previous algorithm which allowed establish the age composition of the red king crab males catches was improved. The parameters of the model of the dependence of the probability of molting on the width of the carapace, which was established earlier according to the tagging data, were changed. The modified model allowed to improve the adequacy of the estimates by reducing the values of the approximation error. Compared to the previous estimates of the age composition, the account of the probable molting history did not lead to a significant revision of the results: all noticeable generations remained the same as before, the time for recording a generation in catches however increased from 10 to 12 years. The parameters of the proposed model are the closest to those for the Kikhchik subpopulation of the red king crab off the Western Kamchatka. The contradiction associated with the discrepancy in the assessment of the maximum age of both the generation and individual specimens is discussed.Practical value. The obtained results can be applied for the red king crab stocks assessment with the help of cohort models.

Fisheries and biological characteristics and state of stocks of the main commercial fish species in Beloye Lake

The current composition of the ichthyofauna and the importance for fisheries of the main fish species in Beloye Lake (Vologda Region) is described in the article based on research materials from 2018 – 2022. The biological features and commercial use of twelve most valuable fish species are summarized as result of the composition of industrial and research catches studies. The size and age composition of catches, the age of puberty, the timing and conditions of spawning, and the feeding patterns of fishes were studied. The influence of net fishing gear with different mesh spacing on commercial fish populations and the magnitude of nets fishing productivity (fishing effort) were studied for the first time. The role of the most important fish species for industrial fisheries in Beloye Lake was assessed.

The inverse association between cancer history and incident cognitive impairment: Addressing attrition bias.

Cancer is inversely associated with cognitive impairment. Whether this is due to statistical handling of attrition (death and censoring) is unknown. We quantified associations between cancer history and incident cognitive impairment among Health, Aging, and Body Composition Study participants without baseline cognitive impairment or stroke (n=2604) using multiple competing-risks models and their corresponding estimands: cause-specific, subdistribution, and marginal hazards, plus composite-outcome (cognitive impairment or all-cause mortality) hazards. All-cause mortality was also modeled. After covariate adjustment (demographics, apolipoprotein E ε4, lifestyle, health conditions), cause-specific and marginal hazard ratios (HRs) were similar to each other (≈ 0.84; P values<0.05). The subdistribution HR was 0.764 (95% confidence interval [CI]=0.645-0.906), and composite-outcome Cox model HR was 1.149 (95% CI=1.016-1.299). Cancer history was positively associated with all-cause mortality (HR=1.813; 95% CI=1.525-2.156). Cause-specific, subdistribution, and marginal hazards models produced inverse associations between cancer and cognitive impairment. Competing risk models answer slightly different questions, and estimand choice influenced findings here. Cancer history is inversely associated with incident cognitive impairment. Findings were robust to handling of competing risks of death. All models also addressed possible informative censoring bias. Cancer history was associated with 16% lower hazard of cognitive impairment. Cancer history was associated with 81% higher all-cause mortality hazard.

Interplay of education and DNA methylation age on cognitive impairment: insights from the Health and Retirement Study.

Few studies have assessed the association of educational attainment on dementia and cognitive impairment through DNA methylation age acceleration, while accommodating exposure-mediator interaction effects. We evaluated the mediation role of six epigenetic clocks with dementia, cognitive impairment non-dementia, and normal cognition, while accommodating exposure-mediator interaction effects. To understand the joint association of low education (≤12 years) and DNA methylation age acceleration (yes/no) in relation to cognitive impairment, we used weighted logistic regression, adjusting for chronological age, sex, race/ethnicity, and cell type composition. We performed four-way mediation and interaction decomposition analysis. Analyses were conducted on 2016 venous blood study participants from the Health and Retirement Study (N=3724). Both GrimAge acceleration (OR=1.6 95%CI 1.3-2.1) and low educational attainment (OR=2.4 95%CI 1.9-3.0) were associated with higher odds of cognitive impairment in a mutually adjusted logistic model. We found additive interaction associations between low education and GrimAge acceleration on dementia. We observed that 6-8% of the association of education on dementia was mediated through GrimAge acceleration. While mediation effects were small, the portion of the association of education on dementia due to additive interaction with GrimAge acceleration was between 23.6 and 29.2%. These results support the interplay of social disadvantage and biological aging processes on impaired cognition.

Assessing the impact of urbanization on forest carbon stocks and social costs using a machine learning approach

Urbanization frequently precipitates urban sprawl, resulting in deforestation and alterations in landscape and land alterations. Such transformations profoundly impact the carbon stocks within metropolitan regions. This study examines the ramifications of urbanization on alterations in carbon stocks within urban forests across ten South Korean cities experiencing substantial urbanization over the past 15 years. Leveraging machine learning techniques and high-resolution satellite imagery, we scrutinize changes in land usage and urban forests, utilizing them to gauge the societal costs linked with shifts in urban carbon stocks. Furthermore, we integrate regional-level data sourced from national forests to enhance the precision of carbon stock estimations. Data analysis reveals that over the 15 years, urban areas expanded at an average rate of 4.43 km2 annually. In comparison, forested areas decreased by an average of −2.19 km2 per year, resulting in an average annual decline of −3171 tC in forest carbon stocks due to urbanization. The fluctuation in carbon stocks across the urban forests of the ten cities ranged from −68 % to 48 % over 15 years, primarily influenced by the extent of preserved forest area, with forest composition playing a secondary role. Concurrently, carbon sequestration efficiency varied between cities, ranging from 8 % to 57 % over 15 years, contingent upon tree type and forest age composition. An approximate loss of 174,380 tCO2eq of carbon stocks attributable to urbanization is estimated, with the associated social cost of increased emissions estimated at $8,893,396. Effective management of carbon emissions and sinks within urban locales is paramount for climate change mitigation, given the substantial contribution of urban areas to global carbon emissions. This study underscores the significance of urban forest management in carbon governance and furnishes valuable insights into nations undergoing rapid urban expansion.

Damage investigation of hybrid flax-glass/epoxy composites subjected to impact fatigue under water ageing

The aim of this study is to investigate the fatigue behaviour of hybrid flax-glass/epoxy composites under repeated impact loading subsequent to water ageing. Different plates of these composite materials were fabricated using the vacuum infusion technique. Five stacking sequences were considered: [F8], [G/F3]S, [G2/F2]S, [G3/F]S, and [G8], where F and G stand for flax/epoxy and glass/epoxy plies, respectively. Water ageing was conducted by immersing the composite specimens in tap water at room temperature for various durations, and until saturation was reached. Fatigue impact tests were carried out using three impact energies: 3, 4, and 5 J. An advanced high-resolution camera was used to monitor the evolution of damage mechanisms occurring on the non-impacted surfaces, while a laser thermometer was considered to track the temperature variations within each composite specimen. The obtained results show that flax-glass hybridization reduces the mass of absorbed water in flax/epoxy composite by up to 70%. Furthermore, there is a more pronounced decrease in longitudinal modulus and maximum stress in aged composites, with reductions of up to 70% compared to unaged ones. Additionally, visible damage occurs even at low energy levels, manifesting from the initial impacts in both aged and unaged composite laminates. Moreover, a correlation between the number of impacts to failure and the cumulative energy is revealed. Ultimately, water aging reduces the strength of the studied composite laminates and their resistance to impact fatigue. Furthermore, the hybrid laminates with high proportion of flax layers are particularly susceptible to water ageing effects.

Trends of stomach cancer incidence and mortality in Shandong province from 2012 to 2012 and predictions from 2023 to 2030

Objective: We aimed to analyse the trend of incidence and mortality of stomach cancer in Shandong province from 2012 to 2022 and predict the development trend from 2023 to 2030. Methods: Data on incidence and mortality of stomach cancer in Shandong province from 2012 to 2022 were obtained from Shandong Cancer Registry. The incidence, age-specific incidence, mortality and age-specific mortality in different years, sexes and urban and rural areas were calculated, the rates were standardized based on the age composition of the Chinese standard population in 2000. The average annual percent change (AAPC) of incidence and mortality was calculated using Joinpoint software. The Bayesian age-period-cohort model was used to predict the trend of stomach cancer incidence and mortality from 2023 to 2030. Results: From 2012 to 2022, the stomach cancer age-standardized incidence rate (ASIR) and age-standardized mortality rate (ASMR) showed a decreasing trend. The ASIR decreased from 27.47/100 000 in 2012 to 16.06/100 000 in 2022 (AAPC=-5.10%, P＜0.001), and the ASMR decreased from 17.69/100 000 to 11.09/100 000 (AAPC=-5.52%, P＜0.001). The ASIR and ASMR of male, female, urban and rural population also showed downward trends. The incidence and mortality rates of men were always higher than those of women, and the difference between urban and rural areas is gradually narrowing. In 2022, the ASIR (16.09/100 000 in urban and 16.03/100 000 in rural) and the ASMR (11.10/100 000 in urban and 11.08/100 000 in rural) of stomach cancer between urban and rural areas were nearly identical. The Bayesian age-period-cohort model predicted that the ASIR of stomach cancer in Shandong would further decrease from 2023 to 2030 (AAPC=-0.51%, P=0.001), but the change tended to be smooth. The incidences in male (AAPC=-1.46%, P=0.010) and rural areas (AAPC=-1.21%, P＜0.001) were still expected to have a little room for decline. The trend of incidences in female and urban areas were not statistically significant. The trend of mortality was consistent with the incidence. Conclusions: The stomach cancer incidence and mortality in Shandong shows a decreasing trend and it is expected to decrease further by 2030. However, the trend tends to be smooth, and the disease burden should be reduced as early as possible for high-risk population and high-risk factors of stomach cancer.

Effect of Silane-Containing Adhesives on Repair Bond Strength between Fresh and Aged Composite Materials-A Pilot Study.

This study investigated the effects of different surface treatments and a silane-containing adhesive on the repair bond strength between fresh and aged resin composites. A total of 140 composite specimens were prepared and aged for 24 h or 4 months. Each group was subdivided into seven subgroups (n = 10) depending on the surface treatment (no surface treatment (NT), sandblasting (SAND), or Sof-lex coarse disc (DISC)) in combination with the use of the silane-containing adhesive ScotchBond Universal Plus (SBU) or an adhesive without silane Prime&Bond Universal (P&B). The same composite was used for the repair as for the primary specimen. Specimens were dark stored in distilled water at 37 °C for 28 days. Shear bond strength was tested at a crosshead speed of 0.5 mm/min. The Kruskal-Wallis test with Bonferroni's post-hoc adjustment (α = 0.05) and the Mann-Whitney U-test were used for the statistical analysis. The results are shown as the median with the interquartile range. The highest bond strength (MPa) was achieved after 24 h in the DISC+P&B (20.39(16.85-28.83)). In the fresh 24 h group, the SAND+P&B (12.25(8.28-15.05)) and DISC+SBU (18.37(15.16-21.29)) were statistically similar. In the 4-month groups, both adhesives and surface treatments performed similarly. The NT, SAND, and DISC groups without adhesives had the lowest bond strength. In the repair of fresh or aged composite, the silane-containing adhesive SBU was not superior to the adhesive without the silane (P&B).

Leveraging Greenspace to Manage Urban Flooding: An Investigation of Nature-Based Solutions Implementation in U.S. Public Parks

Many cities are looking to adopt nature-based solutions (NBS) in greenspace to manage urban flooding and provide diverse co-benefits. Yet little research exists to inform the planning and design of park NBS. This study investigated NBS adoption in 58 public parks across major U.S. cities, using a 2022 survey by the Trust for Public Lands and other secondary datasets. We developed a typology to conceptualize a wide range of park NBS into five high-level categories by size/capacity, location of the gray–green spectrum, and design objectives. We then employed this typology to explore how a park’s adopted NBS types may relate to its landscape and sociodemographic contexts. We found that the most used type of NBS in the studied parks was ECO (a typology we defined as conserving, restoring, or creating ecosystems to mitigate flooding through ecological processes and functions), while the least used NBS type was ENG (a typology we defined as imitating natural infiltration processes but having no living elements). Further, parks that adopted ECO had significantly higher percentages of greenspace in the surrounding, as well as higher flood risks. We also found notable—though not statistically significant—evidence of potential associations between the type of NBS implementation in a park and its nearby neighborhoods’ income level, poverty, and population racial and age compositions. Moreover, our findings indicated that park visitors were more privileged compared to residents living near a park. We concluded that park contextual factors deserve more explicit consideration in the planning and design of NBS and discussed key implications of this study for practice and future research around park NBS for urban flooding.

Passenger car market and regional price discriminations for new cars: Case study and empirical analysis for Poland 2004–2021

Abstract Poland disposes on a large stock of mostly aged private passenger cars. In contrast younger cars still play minor role in individual mobility. The contribution analyzes reasons of lagging modernization by focusing on new cars prices with respect to regional price discrimination. It finds in 2004-2021 substantially increasing new cars prices and regional price discrimination between Poland and Germany. Price differentials were positive, with lower prices in Poland, and increased during time. Producers discriminated by prices increasingly but also limited arbitrage transactions by controlling excess differentials. Optimal regional price discrimination could support car markets developments in Poland by stock age compositions shifts towards younger cars. However, applied discrimination proves in observed market environments not sufficient to achieve a great car market transition in near future.

Factors associated with fall risk increasing drug use in older black and white men and women: the Health ABC Study

BackgroundMost older adults use medications that may increase falls, often defined as fall risk increasing drugs or “FRIDs”. Two definitions for FRIDs, the Centers for Disease Control and Prevention’s (CDC) Stopping Elderly Accidents, Deaths & Injuries (STEADI-Rx) and Swedish National Board of Health and Welfare (SNBHW) definitions, are widely accepted, though include different FRIDs in their definitions. Whether factors associated with FRID use in older adults differ by definition is unknown.MethodsWe hypothesized that factors for FRID use will vary by FRID definition in 1,352 community-dwelling older Black and White adults with medication information in the Health, Aging and Body Composition Study (Health ABC; 2007–08 clinic visit; 83.4 ± 2.8 years; 54.1% women; 65.1% White). Multivariable logistic regression and multivariable negative binomial regression, progressively entering groups of covariates (demographics, lifestyle/behavior factors, and multimorbidity), modeled FRID use (yes/no) and count.ResultsOf 87.0% participants using SNBHW FRIDs, 82.9% used cardiac medications, with lower use of all other FRIDs (range:1.1-12.4%). Of 86.6% participants using STEADI-Rx FRIDs, 80.5% used cardiac medications, with lower use of all other FRIDs (range:1.1-16.1%). Participants with FRID use by either definition were more likely to have chronic health conditions, a hospitalization in the prior year, higher non-FRIDs medication counts, higher Center for Epidemiologic Studies Depression Scale (CES-D) scores, and less physical activity (all p < 0.05). Participants with STEADI-Rx FRID use had poorer vision and higher Modified Mini-Mental State (3MS) scores. In multivariable logistic regression for SNBHW use, hypertension, body mass index (BMI), 3MS scores, and non-FRID count were positively associated with FRID use and poorer vision and Digit Symbol Substitution Test (DSST) scores were negatively associated. In addition to SNBHW factors, higher CES-D scores were associated with STEADI-Rx FRID use. In multivariable negative binomial regression, hypertension, higher BMI, CES-D scores, and non-FRID count were associated with higher FRID count and sleep problems with lower FRID count for both definitions. Higher 3MS and lower DSST scores were associated with higher STEADI-Rx FRID count. Women had lower SNBHW FRID count after adjustments.ConclusionsRisk factors for FRID use in older adults differ slightly by STEADI-Rx and SNBHW FRIDs definition, but are largely similar.

Gaps in predicting water quality impacts of unbound air-cooled blast furnace slag utilized for roadway construction

Air-cooled blast furnace slag (ACBFS) is often used as road construction aggregate. Several incidences of adverse environmental effects have been reported in Indiana where unbound slag has been used. The aggregates that caused issues in the field had been previously approved for use by passing State of Indiana standard slag leaching procedures. The study goal was to test several hypotheses posed to the Indiana Department of Transportation and authors by the industry about slag leaching, and to better understand water quality impacts. Ten slags from two suppliers underwent leaching procedures adopted by two U.S. states, but additional test procedures and material and leachate chemical characterization were also conducted to better interpret results. Aggregates varied in size and age (24 h to 2 years old). Like prior literature reports, the chemical composition among the slag samples was similar. However, water quality impacts observed at the bench-scale in this study differed substantially across the slags. Results were consistent with those previously reported at Indiana field sites, but not with literature reported results from standardized leaching tests (i.e., TCLP, percolation, etc.). In the present study, no relationship was found between slag age and leachate composition. Leachate pH, conductivity, and color levels exceeded thresholds of regulatory and aquatic toxicity significance. For one slag, leachate pH reached 12.9, but the effluent was colorless. During both stagnation and rinsing tests, aqueous chloride, sulfate, and zinc concentrations sometimes exceeded regulatory water quality and aquatic toxicity levels. Repeated rinsing of the slag resulted in water conductivity and sulfate concentration differences. To better understand and predict the impacts of unbound ACBFS, additional fundamental studies and field investigations are recommended. Unbound ACBFS is not recommended for use near environmentally sensitive areas, drinking water sources, habituated areas, and where it may have water contact (i.e., waterways, wetlands, reservoirs, and groundwater).

Machine Learning Approach for Predicting Hypertension Based on Body Composition in South Korean Adults.

(1) Background: Various machine learning techniques were used to predict hypertension in Korean adults aged 20 and above, using a range of body composition indicators. Muscle and fat components of body composition are closely related to hypertension. The aim was to identify which body composition indicators are significant predictors of hypertension for each gender; (2) Methods: A model was developed to classify hypertension using six different machine learning techniques, utilizing age, BMI, and body composition indicators such as body fat mass, lean mass, and body water of 2906 Korean men and women; (3) Results: The elastic-net technique demonstrated the highest classification accuracy. In the hypertension prediction model, the most important variables for men were age, skeletal muscle mass (SMM), and body fat mass (BFM), in that order. For women, the significant variables were age and BFM. However, there was no difference between soft lean mass and SMM; (4) Conclusions: Hypertension affects not only BFM but also SMM in men, whereas in women, BFM has a stronger effect than SMM.

The Impact of Age and Body Composition on the Agreement between Estimated and Measured GFR in Heart Transplant Recipients

Plain Language SummaryAssessing kidney function in heart transplant recipients is paramount to adjust immunosuppressive, antibacterial, and antiviral therapy. An estimate of the kidney function from plasma creatinine measurements is less expensive and time-consuming than a direct measure of kidney function but may be inaccurate in heart transplant recipients. We compared estimated and measured kidney function in 150 heart transplanted patients with a total of 723 kidney function measurements. We find that the kidney function improved the first year after transplantation, which was not detected by the estimate of the kidney function. One year after transplantation, the estimate of the kidney function was, on average, accurate and not affected by body composition, but for the individual patient the estimate was very imprecise, especially in younger patients. The results suggest that kidney function in heart transplanted patients should be measured and not estimated, especially during the first year following transplantation and in younger patients.

The impact of demographic change on value set validity and obsolescence.

To investigate the contribution of demographic trends in countries' age and gender composition to value set validity and obsolescence. Time-trade off (TTO) valuation data from 3 EQ-5D-3L value sets of 20 years or older from the United Kingdom, Japan, and the United States were re-analyzed using Bayesian heteroskedastic Tobit models with sex and age group-specific scale parameters. Original value sets were obtained by weighting the original preference structures with the countries' original demographic composition at the time of the data collection. Updated value sets were created using the original preference structure weighted using the countries' most recent demographic composition. The differences between the original and updated value sets were monitored and compared based on 95% credible intervals. The gender and age composition of the investigated countries changed in all 3 countries over time. The modelled health state preferences also depended on the respondents' gender and age. However, the overall impact of this demographic change on the investigated value sets was negligeable in all 3 countries and this finding was robust to accounting for the impact of ethnicity trends in the United States. Value sets may become redundant and obsolete for various reasons, but demographic change was not identified as a contributing factor.

Factors related to the return to work of head and neck cancer patients diagnosed between 2004–2011 in Belgium: a multivariate Fine-Gray regression model analysis

BackgroundThis study aims to identify the key factors that underlie the return to work (RTW) of head and neck cancer (HNC) patients in Belgium.MethodsWe used data from the EMPCAN database linking data from the Belgian Cancer Registry and the Crossroads Bank for Social Security. We selected HNC patients aged 18–60 at diagnosis who became inactive on the labour market during the follow-up time observed (n = 398). Fine-Gray regression models were used to examine associations between clinical, socio-demographical and work-related factors and RTW over a follow-up of almost 8 years (2004–2011).ResultsThe overall RTW was 21.6%. Stage IV at diagnosis and the use of chemoradiation were associated with a decreased RTW probability but this effect was attenuated by age-adjusted analyses. Multivariate analysis shows that the probability of RTW decreases with age and depends on the household composition. Patients who live alone (SHR 2.2, 95% CI 1.0 – 4.5) and patients who live with another adult and child(ren) (SHR 2.1, 95% CI 1.1 – 4.0) are more likely to RTW than patients who live with another adult without children.ConclusionsThe cumulative incidence of RTW in HNC patients is associated with age and household composition but not with treatment modalities or stage. In future research, this model could be applied to larger cancer patient groups for more accurate estimations. These insights are of importance to better support patients and for informing tailored policy measures which should take into account the sociodemographic profile of HNC patients to tackle societal and health-related inequities and burden of work inactivity.

Anomalously low-mass core-He-burning star in NGC 6819 as a post-common-envelope phase product

Precise masses of red giant stars enable a robust inference of their ages, but there are cases where these age estimates are very precise but also very inaccurate. Examples are core-helium-burning (CHeB) stars that have lost more mass than predicted by standard single-star evolutionary models. Members of star clusters in the database represent a unique opportunity to identify such stars because they combine exquisite asteroseismic constraints with independent age information (members of a star cluster share a similar age and chemical composition). We focus on the single metal-rich ($Z Li-rich low-mass CHeB star KIC4937011, which is a member of the open cluster NGC 6819 (turn-off mass of $ i.e. an age of $ 2.4$ Gyr). This star has a lower mass by $ than expected for its age and metallicity, which might be explained by binary interactions or mass loss along the red giant branch (RGB). To infer formation scenarios for this object, we performed a Bayesian analysis by combining the binary stellar evolutionary framework binary\_c v2.2.3 with the dynamic nested-sampling approach contained in the dynesty v2.1.1 package. We find that this star probably is the result of a common-envelope evolution (CEE) phase during the RGB stage of the primary star in which the low-mass ($&lt;0.71$ main-sequence companion does not survive. The mass of the primary star at the zero-age main sequence is in the range with a log-orbital period in the range days )$. During the CEE phase, $ of material is ejected from the system, and the final star reaches the CHeB stage after helium flashes as if it were a single star with a mass of $ which is what we observe today. Although the proposed scenario is consistent with photometric and spectroscopic observations, a quantitative comparison with detailed stellar evolution calculations is needed to quantify the systematic skewness of the radius, luminosity, and effective temperature distributions towards higher values than observations.