Lower Hazard Rate Research Articles

Firms’ innovation and export survival in a Crisis

ABSTRACT Firms pay sunk costs to enter the export market. However, some firms fail to continue exporting despite paying the high sunk costs. The existing literature has not broadly explored such export market survival for firms, considering their level of innovation. Thus, this study investigates the effects of innovation on firms’ export market survival, using a panel dataset of South Korean manufacturing firms from 2006 to 2019. Adopting a discrete-time hazard model, this study uses patents for measuring innovation and considers the financial crisis period. The study finds that firms with higher innovation levels have lower hazard rates in the export market, implying a higher survival rate. Furthermore, a nonlinear relationship between innovation and export market survival demonstrates diminishing returns to innovation. Innovation is critical to firms’ export market survival, especially during the global financial crisis. Particularly, innovation during the global financial crisis helps high–medium technology firms survive in the export market. These empirical findings suggest that innovation is likely to increase the competitiveness of firms’ products and support their survival in the export market, even during the crisis period.

CAROTID PLAQUE OFFSETS THE SEX DIFFERENCE IN CARDIOVASCULAR RISK IN YOUNG TO MIDDLE AGE HYPERTENSIVE PATIENTS: THE CAMPANIA SALUTE NETWORK

Objective: The aim of the present study is to assess whether presence of carotid artery plaque (CP) has a similar impact on the sex difference in risk for future cardiovascular events. Design and method: we studied 5209 women and men <65 years old with hypertension and free from prevalent cardiovascular disease enrolled in the prospective Campania Salute Network registry were followed over a mean of 5.9 years. Subjects were grouped according to the absence or the presence of CP identified by Doppler ultrasound (intima-media thickness>15mm). Main outcome was major cardiovascular events (MACE; combined acute coronary syndromes, stroke, hospitalization for heart failure and incident atrial fibrillation). Results: Among patients without CP (n = 3139), women were older, with higher systolic BP, cholesterol level and prevalent LVH but lower triglycerides and eGFR, compared to men (all p<0.001). Among patients with CP (n = 2070), women were older, taking higher number of antihypertensive drug, with higher cholesterol level and prevalent LVH but lower triglycerides and eGFR compared to men (all p<0.001). In Cox regression analysis adjusting for cardiovascular risk factors, LVH and antihypertensive treatment during follow up women without CP had lower hazard rate (HR = 0.41) for MACE (n = 107) than men (95% confidence interval [CI] 0.39–0.89, p = 0.01). In contrast, among patients with CP, women had similar HR for MACE (n = 132) as men (HR 0.79 [95% CI 0.54–1.14], p = 0.203). Conclusions: This study demonstrates that presence of carotid organ damage in hypertension contributes to offset the female sex-protection in cardiovascular risk. Thus, expanding previous finding, young to middle-age women and men with hypertension and carotid organ damage have comparable cardiovascular risk.

Modeling unemployment duration, determinants and insurance premium pricing of Malaysia: insights from an upper middle-income developing country.

This paper investigates the behavior and determinants of unemployment in Malaysia, an upper middle-income country with relatively low unemployment but rising labor market mismatches, and derives a model-based insurance premium pricing schedule that broadens the country's unemployment insurance coverage. The unemployment profile is best fitted with Burr distribution, and using survival analysis, the average unemployment duration is found to be the highest for the youths and it decreases gradually after age 20. The results of the Cox proportional hazards model show that age, gender, and education are significant explanatory variables of unemployment. While all age groups are statistically significant in explaining unemployment, the youngest cohort has the least likelihood of being hired, while the older groups are found to have a lower hazard ratio that could be attributed to work experience. The significant gender effect is also characterized by the female workforce taking a longer time to exit unemployment as shown by its lower hazard rate than male workers. Similar to findings for other countries, those with higher education have the highest chance of gaining employment. Fitting the estimated parameters to a standard unemployment insurance premium pricing framework based on the Capital Asset Pricing Model (CAPM), the analysis shows that the coverage of the existing national unemployment insurance scheme can be expanded to all income categories at lower premium prices. The widening of the coverage will contribute to the strengthening of the country’s social safety net in addition to reducing inequalities in the post-COVID-19 period.Supplementary InformationThe online version contains supplementary material available at 10.1007/s43546-022-00287-2.

The effects of contract-type mismatch and matching frictions on unemployment duration: evidence for Portugal

ABSTRACT This paper analyses the impact of matching frictions in the Portuguese labour market on individual unemployment hazard rates and unemployment durations. The coexistence of permanent contracts and temporary contracts in the Portuguese (dual) labour-market is akin to a matching friction, with a contract-type mismatch between jobseekers who prefer permanent contracts, whereas firms, in turn, prefer to offer temporary contracts. The paper uses a rich micro dataset which allows to compute a time and space varying contract-type mismatch index, over 86 local labour markets (job-centers of the Portuguese Public Employment System) and five years. Employing discrete time hazard models and a stock-flow matching mechanism, we find that local labour markets with higher contract-type mismatch rates are characterized by lower hazard rates and longer unemployment duration. Improving the desirability of temporary contracts and information about local contract-type mismatch rates may reduce matching frictions and average unemployment duration.

Joint decision-making model of preventive maintenance and delayed monitoring SPC based on imperialist competitive algorithm

This paper develops a joint decision-making model approach to preventive maintenance and SPC (statistical process control) with delayed monitoring considered. The proposal of delayed monitoring policy postpones the sampling process till a scheduled time and contributes to six renewal scenarios of the production process, where maintenance actions are triggered by scheduled duration of preventive maintenance or the alert of X ¯ chart for monitoring the shift of process mean resulted by deterioration of equipment. By analyzing the evolution of the system in different scenarios, a mathematical model is given to minimize the expected cost per unit time by optimizing values of five variables (scheduled duration without monitoring, scheduled duration of preventive maintenance, sample size, sampling interval and control limit). The results of a numerical example indicate that the hourly cost of the proposed model is lower than the model that delayed monitoring is not considered when the system has a low hazard rate during the early period. Finally, a sensitivity analysis is performed to demonstrate the effect of model parameters.

Servicification and global value chain survival: Firm‐level evidence from India

AbstractIn this article, we study the role of servicification in sustaining global value chain participation. To empirically analyse the role of firm servicification on GVC survival, we draw information from a sample of 1,227 Indian manufacturing firms over 2001–2018. We use a complementary log–log model and find that higher servicification is associated with a lower hazard rate. Moreover, we account for the reverse causality in the model using a two‐stage residual inclusion method and correct for self‐selection using the propensity score matching estimator. Our finding of servicification aiding GVC survival remains robust to the endogeneity concerns. Further, our analysis also underscores the importance of servicification for sustaining GVC participation for firms with short‐trading spells.

Augmented Markov Model for Enhancing Hazard Rate Result of Safety Critical Systems Possessing Diverse Redundant Architecture

Safety-critical systems in various industries such as transportation or nuclear energy have been paid more attention with the development of societies due to increased attachment of importance to the life of human, their property, and nature. While developing such systems, detailed availability and safety characteristics are to be taken into account in parallel with architectural design decisions such as synchronization between different computing units or real-time task management. For fulfilling top-level requirements in international standards, ambitious quantitative targets like 0.012 FIT for HW units are to be reached where the industry has difficulties to achieve it. In this paper, this problem is handled by proposing an augmented Markov model for diverse architectures that is superior to the formulas provided in the main safety standard IEC 61508 and previous studies. With the proposed method it is possible to cover all safety-relevant states, which leads to more accuracy and lower hazard rates helping to reach these ambitious quantitative targets. Besides, the reliability parameters are investigated and optimized to increase safety performance. Consequently, the proposed novel model including enhanced reliability parameters is used for an industry application, namely safety-critical computer used for unmanned metro and high-speed rail transportation. The result obtained by the proposed model is compared with the results obtained using state of art models in literature and using the formulas in IEC 61508. As domain independent references IEC 61508 and Markovian approach are used in the paper, this study is applicable to other safety critical areas such as automotive or avionic industry.

1414Hormone replacement therapy, oral contraceptives and stroke risk

Abstract Background Millions of women use exogenous hormones as hormone replacement therapy (HRT) or oral contraceptives (OC). Still, time-dependent and long-term consequences of exogenous hormones on cerebrovascular health remains unclear. Methods We examined the effects of HRT and OC usage on stroke risk in 256,661 women from UK Biobank, born between 1939 and 1970. Outcomes included any type of stroke, ischemic stroke (IS), intracerebral hemorrhage (IH), and subarachnoid hemorrhage (SH). Exposures were analyzed as time-dependent variables in Cox regression models. Results are expressed as hazard ratios (HR) with 95% confidence intervals. Results During first year of exposure, HRT usage was associated with higher hazard rates of any stroke (HR = 2.12[1.66-2.70]), IS (HR = 1.93[1.04-3.56]) and SH (HR = 2.14[1.23-3.72]) compared to non-usage, which remained significant only for any stroke during remaining years of exposure. Similarly, we observed an increased hazard of any stroke during first year of OC exposure (HR = 2.29[1.34-3.92]), while the hazards were found to be comparable during remaining years of use (HR = 1.03[0.92-1.17]). Conversely, women who previously had been exposed to OC, had a lower hazard rate of any stroke later in life, (HR = 0.88[0.82-0.94]). Conclusions Our findings suggest that HRT and OC use cause immediate changes in hemostatic balance, therefore increasing the short-term stroke risk. However, long-term effects of OC use during reproductive years might improve cerebrovascular health and prevent stroke events later in life. Key messages HRT usage increase the risk of stroke, both short-term and with longer use, while the increased stroke risk might be limited to the first year of OC use.

The Importance of Education for Middle- and Old-Age Mortality in Chile: Estimates From Panel Data Linked to Death Records.

To examine the association between education and mortality by age and gender in Chile. We drew data from 10,147 adults aged 40years and over from the Chilean Social Protection Survey linked to the national death records. We specify five Cox regression models to estimate the main and interaction effects for education levels, age, sex, and mortality. The hazard ratios reduce with increasing education. Secondary and tertiary education levels are associated, respectively, with 34% and 41% lower hazard rates than 0-4years of schooling. Also, the educational gradient in mortality is significantly weaker at older ages, and it does not differ by gender. Our findings endorse the negative association of formal education with adult mortality, uncovering Chile's structural problems despite the economic improvements underway. It also corroborates the importance of novel longitudinal data for mortality analyses in Latin America.

Abstract P645: Sex Differences in the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) Trial

Introduction: Sex differences have been noted in stroke and estrogen is associated with decreased platelet aggregation. The purpose of this study was to assess sex differences in the Platelet Oriented Inhibition in New TIA and Minor Ischemic Stroke (POINT) study. Methods: We performed a secondary analysis of the POINT study. Patients were analyzed by intention to treat group: 1) Males, standard (n=1351) aspirin; 2) Males, intervention (n=1335) clopidogrel+aspirin; 3) Females; standard (n=1098) aspirin; and 4) Females, intervention (n=1097) clopidogrel+aspirin. Groups were compared for baseline demographics via ANOVA followed by Mann Whitney U. A Cox Proportional Hazards Model was used to assess the primary safety and efficacy outcomes. Results: Baseline characteristics were significantly different only for race (p<.001) with white race being most represented. The primary outcome occurred in 6.4% of standard males, 6.7% of standard females, 5.1% of intervention males, and 4.8% of intervention females (p=0.12). Cox models suggest that male intervention participants had lower hazard rate compared to male standard participants (HR=0.79, CI:0.58-1.09) and female intervention participants had a lower hazard compared to male standard (HR=0.76, CI: 0.54-1.07) but this was not statistically significant. Major hemorrhage occurred in 0.4% of standard males, 0.5% of standard females, 0.8% of intervention males, and 1.1% of intervention females (p=0.11). Female intervention subjects had a significantly higher hazard rate of major hemorrhage compared to standard males (HR=2.99, CI:1.06-8.52) with no other between group differences. Conclusion: This study found that there were no significant sex differences in the reduction of recurrent vascular events in the POINT trial. The rate of major hemorrhage was higher in female intervention compared to male standard subjects, but there was no difference in rates between the female groups or the male intervention group. Future studies must provide a sample size with enough power to assess for sex differences to optimize care. Both males and females benefit from combination therapy but the risk of major hemorrhage must be considered.

Participation in disease management programs and major adverse cardiac events in patients after acute myocardial infarction: a longitudinal study based on registry data

BackgroundCardiovascular diseases are still the main cause of death in the western world. However, diminishing mortality rates of acute myocardial infarction (AMI) are motivating the need to investigate the process of secondary prevention after AMI. Besides cardiac rehabilitation, disease management programs (DMPs) are an important component of outpatient care after AMI in Germany. This study aims to analyze outcomes after AMI among those who participated in DMPs and cardiac rehabilitation (CR) in a region with overall increased cardiovascular morbidity and mortality.MethodsBased on data from a regional myocardial infarction registry and a 2-year follow-up period, we assessed the occurrence of major adverse cardiac events (MACE) in relation to participation in CR and DMP, risk factors for complications and individual healths well as lifestyle characteristics. Multivariable Cox regression was performed to compare survival time between participants and non-participants until an adverse event occurred.ResultsOf 1094 observed patients post-AMI, 272 were enrolled in a DMP. An association between DMP participation and lower hazard rates for MACE compared to non-enrollees could not be proven in the crude model (hazard ratio = 0.93; 95% confidence interval = 0.65–1.33). When adjusted for possible confounding variables, these results remained virtually unchanged (1.03; 0.72–1.48). Furthermore, smokers and obese patients showed a distinctly lower chance of DMP enrollment. In contrast, those who participated in CR showed a lower risk for MACE in crude (0.52; 0.41–0.65) and adjusted analysis (0.56; 0.44–0.71).ConclusionsParticipation in DMP was not associated with a lower risk of MACE, but participation in CR showed beneficial effects. Adjustment only slightly changed effect estimates in both cases, but it is still important to consider potential effects of additional confounding variables.

Longitudinal Associations of High-Volume and Vigorous-Intensity Exercise With Hip Fracture Risk in Men.

ABSTRACTMaintenance of vigorous exercise habits from young to old age is considered protective against hip fractures, but data on fracture risk in lifelong vigorous exercisers are lacking. This longitudinal cohort study examined the hazard of hip fractures in 1844 male former athletes and 1216 population controls and in relation to exercise volume and intensity in later years. Incident hip fractures after age 50 years were identified from hospital discharge register from 1972 to 2015. Exercise and covariate information was obtained from questionnaires administered in 1985, 1995, 2001, and 2008. Analyses were conducted using extended proportional hazards regression model for time‐dependent exposures and effects. During the mean ± SD follow‐up of 21.6 ± 10.3 years, 62 (3.4%) athletes and 38 (3.1%) controls sustained a hip fracture. Adjusted hazard ratio (HR) indicated no statistically significant difference between athletes and controls (0.84; 95% confidence interval [CI], 0.55–1.29). In subgroup analyses, adjusted HRs for athletes with recent high (≥15 metabolic equivalent hours [MET‐h]/week) and low (<15 MET‐h/week) exercise volume were 0.83 (95% CI, 0.46–1.48) and 1.04 (95% CI, 0.57–1.87), respectively, compared with controls. The adjusted HR was not statistically significant between athletes with low‐intensity exercise (<6 METs) and controls (1.08; 95% CI, 0.62–1.85). Athletes engaging in vigorous‐intensity exercise (≥6 METs at least 75 minutes/week) had initially 77% lower hazard rate (adjusted HR 0.23; 95% CI, 0.06–0.86) than controls. However, the HR was time‐dependent (adjusted HR 1.04; 95% CI, 1.01–1.07); by age 75 years the HRs for the athletes with vigorous‐intensity exercise reached the level of the controls, but after 85 years the HRs for these athletes increased approximately 1.3‐fold annually relative to the controls. In conclusion, these data suggest that continuation of vigorous‐intensity exercise is associated with lower HR of hip fracture up to old age. © 2022 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Bayesian frailty modeling of correlated survival data with application to under-five mortality

BackgroundThere is high rate of under-five mortality in West Africa with little effort made to study determinants that significantly increase or decrease its risk across the West African sub-region. This is important since it will help in the design of effective intervention programs for each country or the entire region. The overall objective of this research evaluates the determinants of under-five mortality prior to the end of the 2015 Millennium Development Goals, to guide West African countries implement strategies that will aid them achieve the Sustainable Development Goal 3 by 2030.MethodThis study used the Demographic and Health Survey (DHS) data from twelve (12) out of the eighteen West African countries; Ghana, Benin, Cote d’ Ivoire, Guinea, Liberia, Mali, Niger, Nigeria, Sierra Leone, Burkina Faso, Gambia and Togo. Data were extracted from the children and women of reproductive age files as provided in the DHS report. The response or outcome variable of interest is under-five mortality rate. A Bayesian exponential, Weibull and Gompertz regression models via a gamma shared frailty model were used for the analysis. The deviance information criteria and Bayes factors were used to discriminate between models. These analyses were carried out using Stata version 15 software.ResultsThe study recorded 101 (95% CI: 98.6–103.5) deaths per 1000 live births occurring among the twelve countries. Burkina Faso (124.4), Cote D’lvoire (110.1), Guinea (116.4), Nigeria (120.6) and Niger (118.3) recorded the highest child under-5 mortality rate. Gambia (48.1), Ghana (60.1) and Benin (70.4) recorded the least unde-5 mortality rate per 1000 livebirths. Multiple birth children were about two times more likely to die compared to singleton birth, in all except Gambia, Nigeria and Sierra Leone. We observed significantly higher hazard rates for male compared to female children in the combined data analysis (HR: 1.14, 95% CI: [1.10–1.18]). The country specific analysis in Benin, Cote D’lvoire, Guinea, Liberia, Mali and Nigeria showed higher under-5 mortality hazard rates among male children compared to female children whilst Niger was the only country to report significantly lower hazard rate of males compared to females.ConclusionThere is still quite a substantial amount of work to be done in order to meet the Sustainable Development Goal 3 in 2030 in West Africa. There exist variant differences among some of the countries with respect to mortality rates and determinants which require different interventions and policy decisions.

Duration and determinants of fishery trade patterns: Evidence from OECD countries

This study performs a survival analysis on fishery trade patterns for fishery products between Organisation for Economic Co-operation and Development (OECD) countries, and investigates whether survival differences of trade patterns exist between major importers and exporters. The results on both fishery products and their respective OECD countries indicate that survival rate and stability of intra-industry trade are higher than those of inter-industry trade, and horizontal intra-industry trade (HIIT) is also higher than vertical intra-industry trade (VIIT). The results are also in line with previous literature, indicating that differentiated products have a longer duration. Survival rates of trade patterns in HIIT increase (lower hazard rate) with average consumption, contiguity, and common language, and decrease (greater hazard rate) with colonial experience. Finally, the policy measures on tariff margins and non-tariff measures are both inconspicuous in HIIT and VIIT, suggesting that the sustainability of HIIT and VIIT comes from the level of average consumption.

On the different survival rates of Portuguese microbusinesses – the case of projects supported by microcredit

ABSTRACT In spite of their importance to the micro-entrepreneur’s life, Portuguese microbusinesses exhibit a short duration in activity. However, until now there has been scarce attention about the determinants characterizing the microbusiness and/or the micro-entrepreneur. This paper is based on a very comprehensive survey distributed to the microcredit borrowers in Portugal. The main empirical findings suggest that more mature entrepreneurs, with family support, a permanent set of customers, and an awareness of the quality of their goods and services exhibit lower hazard rates of finishing the business. Conversely, high-fixed costs, bad business locations, and periods of economic crisis significantly reduce the duration of the business.

Reliability modelling with redundancy—A case study of power generation engines in a wastewater treatment plant

AbstractPower generators are critical assets in wastewater treatment plants (WWTPs) in Australia and many countries. Better managing the lifetime, minimising failures, improving reliability and availability, and reducing operating and maintenance costs of the power generation assets are still challenging topics for water utilities. This case study aims to develop power generation system reliability and availability modelling considering redundancy to minimise operation and maintenance costs. The two‐parameter Weibull model was used to assess system reliability and availability to power generation engines in WWTPs. The Kaplan‐Meier method (a time‐driven estimation technique) and the log beta‐Weibull model (which is suitable for modelling censored and uncensored data) were used to analyse and validate the modelling results. Shape and scale parameters of the Weibull models were estimated by maximising the log‐likelihood function using non‐linear optimisation. Hazard and reliability functions were calculated using the Weibull model. Results using two‐parameter Weibull, Kaplan‐Meier, and log beta‐Weibull models display low reliability and high hazard rate over time, which was associated with spark plug failure due to a suboptimal start and stop operation strategy.

Education, experience, social network and firm survival: the case of the electrical fittings cluster in Sargodha, Pakistan

In modern era of industrialization, firm survival is widely acknowledged and geared through industrial cluster in developing countries. The present study unfolds the impact of education, experience and social network on firm death by using two rounds of electrical fittings cluster survey from 2008 to 2017. The empirical outcomes from Cox PH model spotlight that entrepreneurs are relatively more educated, rich in experience of production and marketing, have low hazard rate in their business. The empirical analysis also revealed that firm survival can be achieved through strong social network of entrepreneur. The study findings infer that Small and Medium Enterprises Development Authority and United Nations Industrial Development Organization training programs are needed to focus on cluster entrepreneurs and sustained firm survival.

The Birth, Growth and Death of Intertidal Soft-Sediment Bivalve Beds: No Need for Large-Scale Restoration Programs in the Dutch Wadden Sea

Recruitment and fate of all 1436 mussel and oyster beds of the Dutch Wadden Sea were studied for the period 1999–2013. Cox’s proportional hazard rate model with covariates such as orbital speed, exposure time and bed size and type showed that large, low-lying beds that experience a low orbital speed live longer. Yet the most striking result was that oyster and mixed beds have a much lower hazard rate than pure mussel beds. Simulation studies, using the observed recruitment series, which was very variable, and the estimated survival curves, showed large variability in total bed area, implying that the present area, though lower than before, does not point to a systematic deviation from the pre-1990 situation, that is, the situation before intensive fisheries on these intertidal beds and the disappearance of them around 1990. Claims that bivalve bed recovery is impossible without restoration efforts are premature and not supported by our analysis. On the contrary, the observed high survival rate of mixed and oyster beds and the expectation that such beds will predominate in the near future can easily result in larger future bed coverage than what has been measured before.

Left ventricular hypertrophy offsets the sex difference in cardiovascular risk (the Campania Salute Network)

BackgroundIn general, women have lower risk for cardiovascular disease. We tested whether this sex-specific protection persists also in the presence of hypertensive left ventricular hypertrophy (LVH). Methods12,329 women and men with hypertension and free from prevalent cardiovascular disease enrolled in the prospective Campania Salute Network registry were followed over a median of 4.1years. Subjects were grouped according to the absence or the presence of LVH identified by echocardiography using validated sex-specific cut-off values of LV mass index (>47g/m2.7 in women and >50g/m2.7 in men). Main outcome was major cardiovascular events (MACE; combined acute coronary syndromes, stroke, hospitalization for heart failure and incident atrial fibrillation). ResultsThe cardiovascular risk profile accompanying LVH did not differ between sexes, but presence of obesity and diabetes carried higher probability for LVH in women, and LVH was more prevalent in women than men (43.4 vs. 32.1%, p<0.001). Among patients without LVH (n=7764), women had a 35% lower hazard rate (HR) for MACE (n=179) than men (95% confidence interval [CI] 0.44–0.96, p=0.031) in Cox regression analysis adjusting for cardiovascular risk factors and antihypertensive treatment during follow up. In contrast, among patients with LVH (n=4565), women had a similar HR for MACE as men (HR 0.94 [95% CI 0.69–1.30], p=0.720). ConclusionThis study demonstrates that presence of LVH in hypertension offsets the female sex-protection in cardiovascular risk. Thus among hypertensive subjects with LVH, women and men have comparable cardiovascular risk.

College Dropouts and Poor Individuals

Many studies have examined the reasons behind college drop-outs. In contrast to the literature, this study focuses on the impact of a situation of being poor controlling for parents’ characteristics, spouse characteristics and success indicator. Using Cox Proportional Hazard model, the study then finds that the individuals who are from poor families have lower hazard rate of leaving college relative to those who are from non-poor families. When the same analysis is done under two different settings (namely, under academic-issue framework and financial-issue framework), it turns out that the effect of poor variable is still significant under financial-issue framework but it is no longer significant under academic-issue framework.