Status Transitions Research Articles

Metal bioavailability during the periodic drying and rewetting process of littoral anoxic sediment

High water-level fluctuations (WLFs) usually lead to the periodic drying and rewetting of littoral sediment, proven to influence the transformation of various sediment contaminants. However, details regarding metal bioavailability variations remain unclear. In this study, oxidation–reduction status transition, metal fraction transformation, and the development of the acid volatile sulfide (AVS) and the simultaneously extracted metals (SEM) were investigated to assess the variations of metal bioavailability in the littoral anoxic sediment during the drying–rewetting process. A series of sediment cores were collected from the littoral area near the mouth of Nanfei River in Lake Chaohu, China, with half of them exposed to dark conditions with an overlying water cover (the control treatment). The other half was dried through the removal of overlying water and then exposed to air and sunlight (the drying treatment). Every 5 days, three of the dried sediment cores were rewetted for 3 days with lake water collected in situ. Various characteristics were analyzed for both the control and drying sediment cores. The drying and rewetting experiment was carried out for 30 days, and the bioavailability of metals was then evaluated thoroughly through data analyses. The periodic drying and rewetting process led to the oxidation of the anoxic sediment with a pronounced increase in oxygen penetration depth and redox potential, and a decrease in AVS concentrations in the drying treatment after 15 days of experimentation. Significant increases in the values of the ratio of SEM and AVS, the difference between SEM and AVS, and the organic carbon normalized difference between ΣSEM and AVS were retrieved for the drying treatment after process completion. The increase of metal bioavailability to aquatic organisms was consequently predicted, with the most significant concerns noted regarding Cd and Pb due to their transformation to less firmly bound fractions. The periodic drying and rewetting process could increase the bioavailability of metals in littoral anoxic sediment. Therefore, this process should be given more attention during future management of water level and remediation of littoral sediment in similar areas.

Healthy lifestyle behaviors and transitions in frailty status among independent community-dwelling older adults: The Yabu cohort study

Frailty is a dynamic condition that can worsen or improve. Although previous studies have identified demographic and intrinsic factors associated with transitions in frailty status, less evidence is available regarding associations with daily activities. This longitudinal study examined associations of behavioral factors with incident frailty, adverse events (e.g. residence in a nursing home, hospitalization, and death), and frailty improvement among older adults. The analysis included data from 3,769 independent older adults aged 65 years or more (mean age, 76.3 ± 7.2years; proportion of frail participants, 30.1%) from the Yabu cohort study (baseline, 2012; follow-up, 2017). The Kaigo-Yobo Checklist, a standardized questionnaire, was used to assess frailty status (non-frail or frail) and seven behavioral factors: farming, shopping, exercise, eating habit, intellectual activity, social participation, and smoking. At the 5-year follow-up survey, the proportions of participants transitioning from non-frail to frail, from non-frail to incident adverse events, from frail to non-frail, and from frail to incident adverse events were 16.8%, 13.9%, 15.2%, and 50.1%, respectively. In the analysis of non-frail participants, farming, exercise, intellectual activity, and social participation were associated with lower odds of becoming frail and experiencing adverse events. In the analysis for frail participants, farming, intellectual activity, and social participation were significantly associated with improvement in frailty status, and farming, shopping, and social participation were associated with lower odds of incident adverse events. These findings suggest that farming, healthy daily activities, and social participation help improve and prevent frailty/adverse events.

Expanding the Analytical Capacities of the Labour Force Survey

The article formulates a number of recommendations on the areas of expanding the analytical capacities of the National Labor Force Survey with consideration to the European statistics and the needs of the current phase of labor reforms in Ukraine. The first area is about implementing the recommendations of the International Labor Organization No 198 “On Labor Relations” and the updated International Classification of Status in Employment (ICSE-18), which are becoming critically important in view of the announced reform in labor law and liberalization of labor relations. As the Labor Force Survey is the only regular source of information collected from people about their actual status on the labor market, it is supposed to lay the basis for the statistical observation of the processes and implications of the labor relations reform. The program of the National Labor Force Survey has already included the major part of questions providing for the criteria for identifying the status in employment and determining the types of labor relations, but their formulations have to be adapted to the updated labor law. The second area concerns with the deeper processing of the survey results. It is high time to implement seasonal adjustment for the indicators of employment and unemployment. Once the experimental development of Eurostat on the statistics of labor market flows is used, it will enable for analysis and forecasting of the status transitions (employment – unemployment – inactivity) considering the individual characteristics of respondents. The labor life expectancy, estimating one’s potential lifelong participation in the labor market, should be computed for analysis of the comprehensive impact of social and demographic change and interactions of life cycles. The third area concerns with a more sensitive approach to vulnerable groups on the labor market. Due to the demographic change like reduction of the generations in working age and ageing of the population, all the potential reserves of the labor force need to be involved. A large part of them is associated with the groups that are regarded as vulnerable or the ones distanced from the labor market, which need additional measures for activation and support. To this end, it is recommended to extend the program of the National Labor Force Survey by including analytical aspects supposed to provide information about labor market participation and employment characteristics of persons with disabilities and older employees (55–64 years), about opportunities for learning lifelong and combining work and family duties. Also, studies of the analytical capacities of the National Labor Force Survey have to cover in-depth module interviews as a supplement to the core program of regular survey.

Associations Between Nicotine Metabolite Ratio and Gender With Transitions in Cigarette Smoking Status and E-Cigarette Use: Findings Across Waves 1 and 2 of the Population Assessment of Tobacco and Health (PATH) Study.

Nicotine metabolite ratio (NMR), the ratio of trans 3'-hydroxycotinine to cotinine, is a biomarker of nicotine metabolism. Discrepant findings among clinical trials and population-based studies warrant replication on whether higher NMR, or faster nicotine metabolism, is associated with quitting cigarette smoking. Associations of NMR and e-cigarette use are largely unknown, as well as the relationship between NMR and gender on quitting cigarette smoking or e-cigarette use. The Population Assessment of Tobacco and Health (PATH) Study is a nationally representative, longitudinal cohort study assessing tobacco use in the US population. In the current study, the PATH (waves 1 and 2; adult interviews) was used to evaluate longitudinal predictions in relationships among NMR and gender and their association with transitions (quit vs. current stable) in cigarette smoking status and e-cigarette use status across waves 1 and 2 of the PATH study. NMR and gender were not significantly associated with quit behavior for combustible cigarettes. Regarding e-cigarettes, a significant two-way interaction demonstrated that women with higher NMR were less likely to quit e-cigarette use compared to women with lower NMR (odds ratio [OR] = 0.10, 95% confidence interval [CI] = 0.02-0.57; p = .01). Findings identify that women with faster nicotine metabolism were 10 times less likely to quit e-cigarettes compared to women with slower nicotine metabolism across waves 1 and 2 of the PATH study. Results suggest that NMR may be used as a biomarker for transitions in e-cigarette quit behavior for women. Findings identify that women with faster nicotine metabolism were 10 times less likely to quit e-cigarettes compared to women with slower nicotine metabolism. Results suggest that NMR may be used as a biomarker for transitions in e-cigarette quit behavior for women. Establishing parameters for NMR collection and for the use of NMR as a biomarker for cigarette smoking behavior and e-cigarette use is an important next step, and may have implications for early intervention and treatment for cessation.

Perceived stress level and its related factors in Chinese adult residents aged 18-65 in 15 provinces (autonomous regions and municipalities) in 2015

To investigate the perceived stress prevalence of adult residents aged 18-65 in 15 provinces(autonomous regions and municipalities) and its related factors. Adults aged 18 to 65 years, with middle school education or above and complete demographic and socioeconomic characteristics, lifestyle, disease history and physical measurements were selected as study subjects from the database of Nutritional Status and Health Transition of Chinese Residents Project in 2015. Chinese perceived stress scale(CPSS) was used to evaluate the perceived stress level of participants, and percentile regression model was used to analyze the correlation between related factors and perceived stress. A total of 6679 subjects were enrolled in this study. The mean and median of perceived stress scores were 22. 6 and 24. 0, respectively. The percentile regression model showed that age was positively associated with perceived stress in the 5 th, 25 th, 50 th and 95 th percentiles, and the difference between the two groups decreased with the increase of perceived stress score(P5, β=1. 31, 95%CI 0. 38-2. 24; P25, β=0. 91, 95%CI 0. 28-1. 53). Compared with the control group, adults with junior high school education had a high level of perceived stress in higher percentiles(P50, β=0. 81, 95%CI 0. 32-1. 30; P75, β=0. 42, 95%CI 0. 11-0. 72; P95, β=0. 62, 95%CI 0. 06-1. 18). Perceived stress levels in the 50 th, 75 th and 95 th percentiles were lower in the married adults than in the control group(P50, β=-0. 81, 95%CI-1. 40--0. 23; P75, β=-0. 39, 95%CI-0. 68--0. 10; P95, β=-0. 95, 95%CI-1. 79--0. 12). In the 5 th, 25 th, 50 th and 75 th percentiles, the perceived stress level of no workers is higher than that of workers, and the difference decreases with the increase of perceived stress score(P5, β=1. 31, 95%CI 0. 32-2. 31; P75, β=0. 53, 95%CI 0. 35-0. 71). Income level showed a positive association with perceived stress across the entire conditional perceived stress distribution(P<0. 05). People with low levels of physical activity had higher levels of perceived stress in the 25 th, 50 th, and 75 th percentiles than the control group(P25, β=1. 15, 95%CI 0. 41-1. 90; P50, β=1. 09, 95%CI 0. 62-1. 56; P75, β=0. 28, 95%CI 0. 07-0. 49). Urbanization level and alcohol consumption and other factors had influence on perceived stress in different percentile(P<0. 05). No significant correlation was found between housing ownership, smoking, sleep duration and perceived stress. The perceived stress level of adult residents aged 18 to 65 in 15 provinces of China is on the high level on the whole, which is correlated with age, marital state employment, annual per capita income, physical activity level and other factors.

Assessing wage status transition and stagnation using quantile transition regression

Workers in Taiwan overall have been suffering from long-lasting wage stagnation since the mid-1990s. In particular, there seems to be little mobility for the wages of Taiwanese workers to transit across wage quantile groups. It is of interest to see if certain groups of workers, such as female, lower educated and younger generation workers, suffer from the problem more seriously than the others. This work tries to apply a systematic statistical approach to study this issue, based on the longitudinal data from the Panel Study of Family Dynamics (PSFD) survey conducted in Taiwan since 1999. We propose the quantile transition regression model, generalizing recent methodology for quantile association, to assess the wage status transition with respect to the marginal wage quantiles over time as well as the effects of certain demographic and job factors on the wage status transition. Estimation of the model can be based on the composite likelihoods utilizing the binary, or ordinal-data information regarding the quantile transition, with the associated asymptotic theory established. A goodness-of-fit procedure for the proposed model is developed. The performances of the estimation and the goodness-of-fit procedures for the quantile transition model are illustrated through simulations. The application of the proposed methodology to the PSFD survey data suggests that female, private-sector workers with higher age and education below postgraduate level suffer from more severe wage status stagnation than the others.

Analysis on detection status of cardio-metabolic related risk factors in women aged 15-49 years in 15 provinces in China

Objective: To analyze the prevalence, co-prevalence of cardiovascular metabolic (CM) risk factors in women aged 15-49 years in China, and describe the influence of social economic factors on them. Methods: The project data of Nutritional Status and Health Transition of Chinese Residents in 2015 were used. The changes in epidemiological characteristics of central obesity, elevated blood pressure, FPG and TG, decreased HDL-C and co-prevalence of the risk factors in women aged 15-49 years were analyzed. According to the definition of the metabolic syndrome released by the International Diabetes Federation in 2005, five cardio-metabolic risk factors appeared as central obesity, increased triglycerides, decreased HDL-C, increased blood pressure and increased plasma glucose. Co-prevalence of risk factors was defined as detecting 2 or more risk factors in a person at the same time. Multivariate logistic regression model was used to analyze the relationship between socioeconomic factors and metabolic risk factors. Results: In 2015, in women aged 15-49 years in 15 provinces, the detection number (rates) of central obesity, elevated blood pressure, FPG and TG, decreased HDL-C, at least one CM risk factor and co-detection rate of CM risk factors were 944 (47.4%), 464 (23.3%), 123 (6.2%), 327 (16.4%), 1 025 (51.5%), 1 501 (75.4%), and 874 (43.9%), respectively. Compared with women aged 15-19 years, the women in age group of 25-, 30-, 35-, 40-, and 45-49 years were more likely to have central obesity (P<0.05), the women in age group of 30- 35-, 40-, and 45-49 years were more likely to have elevated blood pressure (P<0.05), the women aged 45-49 years were more likely to be affected by one or more CM risk factors (P<0.05), but the women in age group 25-29 years group had lower risk for elevated FPG (P<0.05). The odds of having central obesity, elevated blood pressure, FPG and TG, decreased HDL-C, at least one CM risk factor and co-prevalence of CM risk factors in women with BMI≥24.0 kg/m(2) were 14.16, 3.05, 2.46, 2.49, 2.42, 9.79 and 7.39 times higher than those in the women with BMI of 18.5-24.0 kg/m(2), respectively. The odds of having elevated FPG and TG in women aged 15-49 years in western China and the odds of having elevated blood pressure and FPG in women aged 15-49 years in eastern China were significantly higher than those in central China. No significant correlations were found between the prevalence and co-prevalence of CM risk factors and income level or urban and rural area residences in women aged 15-49 years. Conclusions: Age, BMI level and living area were the major influencing CM risk factors. The precise prevention and control measures should be taken in time for the adverse changes in CM risk factor prevalence.

For better or for worse: Marital status transitions and sexual life in middle and later life

Marital status and marital status transitions have known implications for adults’ mental and physical quality of life. Less attention has been paid, however, to the implications of marital status and transitions for sexual quality of life, particularly among the aging population. The present study analyzed three-wave longitudinal data from the National Survey of Midlife Development in the U.S. (1995–2014) in order to examine the effects of marital status/transitions on adults’ frequency of sexual activity, sexual satisfaction, effort put into sexual life, and control over sexual life. Further, this study assessed whether the implications of marital status/transitions for adults’ sexual quality of life varied according to (a) pre-transition reports of sexual quality of life, (b) gender, and/or (c) age. Multilevel lagged dependent variable models analyzed 2,869 observations drawn from 1,769 midlife and older adults over a two-decade span. Results indicated that the implications of marital status and marital status transitions for sexual life (a) were contingent upon baseline context across all four sexual quality of life outcomes, (b) varied by gender across three of the four sexual quality of life outcomes, and (c) varied only slightly by age concerning frequency of sexual activity. Overall, findings indicated that marital status transitions may be either beneficial or detrimental for adults’ sexual lives, depending on prior context; marital status transitions were most beneficial for sexual quality of life when baseline reports of sexual life were poor. Moreover, women were less likely to reap the potential rewards of marital status transitions such as divorce and widowhood, reflecting stronger social and normative constraints upon unmarried women’s sexuality, particularly for older women. We situate these findings within the growing literature concerning marital status transitions, the “graying of divorce,” and sexual life among the aging population.

Transitions in paternal social status predict patterns of offspring growth and metabolic transcription.

One type of parental effect occurs when changes in parental phenotype or environment trigger changes to offspring phenotype. Such nongenetic parental effects can be precisely triggered in response to an environmental cue in time-locked fashion, or in other cases, persist for multiple generations after the cue has been removed, suggesting multiple timescales of action. For parental effects to serve as reliable signals of current environmental conditions, they should be reversible, such that when cues change, offspring phenotypes change in accordance. Social hierarchy is a prevalent feature of the environment, and current parental social status could signal the environment in which offspring will be born. Here, we sought to address parental effects of social status and their timescale of action in mice. We show that territorial competition in seminatural environments affects offspring growth. Although dominant males are not heavier than nondominant or control males, they produce faster growing offspring, particularly sons. The timing, effect-size, and sex-specificity of this association are modulated by maternal social experience. We show that a change in paternal social status is sufficient to modulate offspring weight: from one breeding cycle to the next, status-ascending males produce heavier sons than before, and status-descending males produce lighter sons than before. Current paternal status is also highly predictive of liver transcription in sons, including molecular pathways controlling oxidative phosphorylation and iron metabolism. These results are consistent with a parental effect of social experience, although alternative explanations are considered. In summary, changes in paternal social status are associated with changes in offspring growth and metabolism.

A Multicenter International Study to Evaluate Different Aspects of Relationship Between MS and Pregnancy

Since multiple sclerosis (MS) commonly affects women of child-bearing age, having a deeper understanding of «the effects of pregnancy on the disease» and «the effects of MS on pregnancy» is important.Although,studies on the effects of pregnancy and usage of disease-modifying therapies on MS are still ongoing, there is also a need to gather information regarding the reproductive practices and the attitude of females with MS in different countries. Females diagnosed with MS were included if they had at least one conception with complete clinical data (n=701).Data were obtained from medical records and the questionnaire which was specifically designed for this study.Detailed demographics, clinical information, data regarding the pregnancies,abortions, relapses during pregnancy and post-partum first 3 months,the presence of drug exposure during pregnancy, lactation, reproductive attitudes of females after being diagnosed as MS were collected. 1692 pregnancies in 701 females were evaluated.While mean age at MS onset was 28 ± 9 years, mean age during recruitment was 37 ± 9 years. The majority of patients (85.9%) had relapsing-remitting MS (RRMS). The mean EDSS was 2.0 (±1.8) (0–8). The number of pregnancies recorded was more frequent in the pre-MS than post-MS period. The mean age at first pregnancy was 24.32(±6.72). In total, 22.6% of 124 attacks during pregnancy were recorded in the first trimester; while 17.7% in the last trimester,45.2% during the post-partum period.Our data revealed that as the number of pregnancies increased, the age of MS onset was delayed. The number of pregnancies had no significant effect on the course of MS, Expanded disability Status Scale (EDSS) progression and transition to progressive phase. 184 patients (26.25 %) stated that the diagnosis of MS had an impact on their decision not to become pregnant.

The Association between Living Status Transitions, Behavior Changes and Family Relationship Improvement among Methadone Maintenance Treatment Participants in Guangdong, China.

The quality of family relationships is important for individual and family well-being. Improving family relationships is also an important goal in methadone maintenance treatment (MMT). Little is known about factors associated with the improvement of family relationships among MMT clients. This study aimed to identify factors associated with family relationship improvement in MMT. We retrospectively analyzed existing data from 2006 to 2014 at 15 MMT clinics in Guangdong, China, including 2171 subjects with 4691 follow-ups. Generalized estimating equations were used to investigate the association between living status transitions, behavior changes and family relationship improvement, with covariates controlled for. Family relationship improvement was found in 23.1% of all follow-up intervals. Participants who began living with family, living on a regular wage, and gained employment were more likely to have improved family relationships. The quality of family relationships also improved among participants who ceased contact with drug-addicted fellows, ceased drug use, and those who were sexually active. These results suggest that improvement in living status, positive changes in drug use, and sexual activity are associated with family relationship improvement and corresponding interventions may be developed to facilitate clients’ recovery.

Transnational Social Capital in Migration: The example of Educational Migration between Bulgaria and Germany

Focusing on student migration from Bulgaria to Germany, this article examines what types of social capital are accumulated, transformed and implemented through migration, who profits from the investment, and how. The empirical work consists of 60 narrative biographical interviews with migrants and returnees to Bulgaria. The research reveals that the accumulation and investment of social capital takes place throughout the migratory trajectory—starting well before leaving—and is embedded in a transnational social space. Transnational networks exist as family, peer and professional networks, and all of them have a specific meaning for the migrants. Family networks are naturally present; they provide bonding social capital and thus have a stabilizing function for the individual’s identity. Professional networks have a strongly bridging function, helping the young migrants to manage status transitions. After return the transnational social capital acquired during the migratory stay helps returnees to re-integrate and find their way into the Bulgarian labour market. It also encourages them to pursue activities which are meaningful for civil society development, or for innovative (social) entrepreneurship. Thus, transnational social capital helps migrants to align their biographical development to the future, considering the post-transformative environment of Bulgaria, thereby helping to manage transformative changes and supporting societal modernization processes.

Transition of post-disaster housing of rural households: A case study of the 2015 Gorkha earthquake in Nepal

To achieve post-disaster recovery of rural households in developing countries, it is necessary to understand the recovery conditions and the factors that play significant roles in the decision-making process. We aimed (1) to explain the transition of the residential status (i.e., type of places or houses in which affected households stay) after the disaster event and (2) to reveal the factors affecting the housing decisions. We interviewed 124 rural households in Nepal affected by the 2015 Gorkha earthquake to understand the residential status transition up to two and a half years after the earthquake. As a result, more than 50 transition patterns were observed. Social relations in the community were important immediately after the earthquake, followed by the physical resources and subjective factors. Financial resources became influential at a later stage of recovery. The number of households that repaired or rebuilt their houses boosted one year after the earthquake. However, the households who moved to unrepaired houses did not upgrade to repaired or rebuilt houses. This implies that the disparity in residential status among affected households had been determined even before they left the temporary houses and began the recovery process. Our results suggest that, for the prevention of recovery disparity, it is essential to support the recovery of individual households before the community starts the process, identifying their priorities and urgent needs and considering their circumstantial conditions. Thus, our study provides empirical data for effective recovery of vulnerable rural communities after disasters.

INTERNET USE AND SOCIAL ISOLATION: THE SIGNIFICANCE OF LIFE TRANSITIONS

Social isolation has emerged as a significant public health risk for older people, and can be triggered by a number of life transitions in old age, such as retirement, bereavement, and divorce. Using the Health and Retirement Study (HRS), the current study aims to examine how internet use is associated with significant life transitions in marital and employment status in a longitudinal analysis. Results showed that using the internet was associated with lower social isolation and depression for people who became separated or divorced, but no significant interaction was observed for people who became widowed. On the other hand, becoming unemployed and using the internet was associated with more depressive symptoms. The results indicate that the link between psychological well-being and use of internet differs depending on the context of life transitions and may not have universal benefits for reducing social isolation.

Labor-market mobility among persons with disabilities

Persons with disabilities face many obstacles in their attempts at social integration, particularly in the labor market. The study investigates patterns of transition among different employment situations by persons with disabilities relative to persons without disabilities. It also studies employment transitions among individuals who hold part-time jobs in relation with their long-term level of physical disability. Probability models that explain transitions in employment status among persons aged 25-54 in dependence of possible changes over time in the severity of their disability. Patterns of disability do not persist over time. Improvement of disability does not increase the share of persons employed in both investigation periods as well as the share of those not employed at both times. Unexpectedly, few people who are not employed and whose disabilities improve manage to join the labor market when their disabilities improve. Also, few who are employed part-time and whose disabilities improve managed to switch to larger posts when their disabilities improve. The labor market imposes scars on people with disability whose condition improves somewhat, hindering their chances of re-integration into the workforce. To assure them a regular income and employment rehabilitation, public-policy programs should be expanded.

Stability of clinically relevant depression symptoms in old-age across 11 cohorts: a multi-state study.

To study the temporal dynamics of depression symptom episodes in old-age and the related influence of risk factors. Data from 41362 old adults (54.61% women; mean age=75.30, SD=6.20) from the Ageing Trajectories of Health - Longitudinal Opportunities and Synergies (ATHLOS) project were used. Depressive symptoms were followed over an 18-year period. A multi-state model, comprising three statuses (no depression, new clinically relevant episode of symptoms and episode persistence), was fitted. Multinomial regression was used to study the role of risk factors in status transition. Almost 85% of participants showed no depression, but prevalence became lower over time (B=-0.25, P<0.001). New episode point prevalence was over 5.30% with a significant probability of moving to persistence status (transition probability=0.27). Episode persistence became evident in 9.86% of episode status transitions, with increasing rate over time (B=0.54, P<0.01). Loneliness was proven to be the strongest predictor of episode emergence (OR=17.76) and persistence (OR=5.93). The course of depression tends to become chronic and unremitting in old-age. This study may help to plan interventions to tackle symptom escalation and risk factor influence.

Longitudinal association between panic disorder and health care costs in older adults.

To analyze whether probable panic disorder (PD) is associated with health care costs in older age over time. Data regarding individuals aged 65 and over were derived from two waves of the ESTHER cohort study (nt1 = 2,348, nt2 = 2,090). Probable PD was assessed using the panic screening module from the Patient Health Questionnaire. Health care costs were obtained through monetary valuation of self-reported health care use data. Fixed effects regressions analyzed the association between transitions in probable PD status and change in health care costs, while adjusting for potential confounders. On a descriptive level, study participants with a positive PD screening displayed higher three-month health care costs compared to those without (incremental costs: € 259 for t1 , € 1,544 for t2 ). Transitions in probable PD were associated with an approximate increase of 65% in outpatient health care costs (β = 0.50, p < .05). There was no significant association between probable PD transition and change in any other cost category. Using longitudinal data, our results highlight the economic consequences of probable PD in older adults. Future research should address whether reducing PD in older adults may reduce the associated economic burden and analyze underlying mechanisms.

Ant colony system algorithm for generalized trapezoidal fuzzy capacitated vehicle routing problem

Traffic congestion causes late arrivals at customers and long travel times resulting in large transport costs. Traffic congestion also can result in the travel time of the vehicle from one place to another cannot be determined precisely even though the distance travelled is the same. In this paper, fuzzy capacitated vehicle routing problem (FCVRP) with travel time expressed by generalized trapezoidal fuzzy numbers is addressed. The fuzzy model is reduced to corresponding crisp one using fuzzy ranking method. Then, we propose ant colony system (ACS) algorithm with the status transition rule, global pheromone trail update and local pheromone trail update for constructing the optimal vehicle routes of the reduced problem. A numerical example of Bright gas 5.5 kg distribution is demonstrated to find the optimal solution of the proposed method. Travel time are obtained basing on real data measured by an electronic system at ten different times. The proposed method is simpler and more computationally efficient when compared to existing methods.

Process stability analysis and weld formation evaluation during disk laser–mag hybrid welding

For monitoring process stability and evaluating weld formation in laser–metal active gas arc welding (MAG) hybrid welding, this work proposes a new method that combines instantaneous status analysis and continuous stability analysis with a double high-speed photography system. Instantaneous physical phenomena were extracted from the top and bottom surfaces, which included information on arc light, metallic vapour, spatter, and the flow of the bottom molten pool. These features were used to evaluate the instantaneous status by analysing the keyhole status and droplet transition status in 316 stainless steel laser–MAG hybrid welding. The grey-level co-occurrence matrix (GLCM) and Gabor wavelet were used to measure the instantaneous status of the bottom molten pool in the spatial and frequency domains, respectively. Multiple physical phenomena of the top surface were obtained by morphological methods. The process stability mechanism was analysed based on visual features, and the time–frequency distributions of the process features were investigated for the stability analysis and formation evaluation. Unstable frequencies in the laser–MAG hybrid welding process and their influence factors were presented. Additionally, the relationship between the stability of the welding process and the weld formation was analysed by a continuous analysis method. The experimental results showed that the instantaneous analysis method effectively evaluated the instantaneous status of laser–MAG hybrid welding process, and the global stability of the continuous analysis method directly reflected the weld formation. The proposed method could be used to monitor the stability and weld formation of the laser–MAG hybrid welding process.

Comparable Risk of Suicidal Ideation between Workers at Precarious Employment and Unemployment: Data from the Korean Welfare Panel Study, 2012-2017.

Precarious employment and unemployment are important factors that impact suicidal behavior. This study investigated (1) how employment transitions among permanent employment, precarious employment, and unemployment are associated with suicidal ideation in working employees and compared (2) whether individuals transitioning among these three states were more vulnerable than those remaining. Using nationally representative longitudinal data between 2012–2017, a total of 25,862 adults aged 25 to 59 years old without a record of suicidal ideation were included at baseline. Transitions in employment status (permanent work, precarious work, or unemployment) and suicidal ideation were analyzed using hierarchical logistic regression models. Compared to the “permanent to permanent” group, individuals in the “permanent to precarious” (odds ratio (OR) 1.74, 95% confidence interval (95% CI) 1.29–2.35], “permanent to unemployment” (OR 1.97, 95% CI 1.32–2.96), “precarious to precarious” (OR 1.86, 95% CI 1.21–2.85), and the “precarious to unemployment” (OR 1.43, 95% CI 1.05–1.95) groups had higher odds of suicidal ideation. The magnitude of such odds was generally higher than that of individuals at annual unemployment or precarious states. The results show that adults moving in and out of different employment states have higher odds of suicidal ideation than individuals at annually static precarious or unemployment status.