Essays on Parental Leave and Family Labour Supply

This thesis studies married couples\u27 decisions regarding labour supply, fertility, and take-up of parental leave. Importantly, it emphasizes household interactions in a family labour supply framework where husbands and wives jointly make decisions. In Chapter 2, I describe how differences in married individuals\u27 time allocations between Canada and the U.S. may be related to different parental leave policies in the two countries. First, I document background information on parental leave policies and take-up behaviour in the two countries. Second, I analyze married individuals\u27 time allocations using data from the General Social Survey (GSS) for Canada and American Time Use Survey (ATUS) for the U.S. I examine the role of having children on their parents\u27 time allocations across market work, child care, household chores, and leisure and make cross-country comparisons. In Chapter 3, I investigate the effects of maternity leave policies on married couples\u27 fertility and employment decisions. I develop and characterize a unique household search model that features home production and endogenous fertility choice. I characterize reservation rules in the household search model and find that this model can generate patterns that cannot be generated by an individual search model. In particular, I parameterize a benchmark model that provides 12 weeks of unpaid leave as in the U.S. I use a parameterized model to examine the impact of an extended paid maternity leave policy on fertility rates and household employment. I find that a longer paid maternity leave increases fertility rates, lowers fraction of dual-earner couples, and increases the fraction of single-earner couples. In Chapter 4, I examine what prevents married fathers from taking parental leave despite its availability in Canada. As possible explanations, I consider gender differences in rental rates of human capital, wage growth processes, wage penalties for time off from work, preferences for leisure, and productivity in home production. I document supporting empirical evidence for the possible explanations. Next, I develop a life-cycle model of family labour supply that features learning-by-doing human capital accumulation and time allocations across market work, leisure, and home production. Then, I quantify the relative importance of these explanations within the model. I find that lower home productivity in the presence of an infant, higher rental rates of human capital, and higher wage penalties for not working for fathers are the main contributors to the low take-up of fathers. Finally, I conduct policy experiments to highlight the role of cash benefits and paternity leave on fathers\u27 take-up of leave. The results show that fathers\u27 take-up rates are responsive to an increase in an income replacement rate combined with the introduction of paternity leave

Projection of Cancer Incidence and Mortality From 2020 to 2035 in the Korean Population Aged 20 Years and Older

Objectives: This study aimed to identify the current patterns of cancer incidence and estimate the projected cancer incidence and mortality between 2020 and 2035 in Korea. Methods: Data on cancer incidence cases were extracted from the Korean Statistical Information Service from 2000 to 2017, and data on cancer-related deaths were extracted from the National Cancer Center from 2000 to 2018. Cancer cases and deaths were classified according to the International Classification of Diseases, 10th edition. For the current patterns of cancer incidence, age-standardized incidence rates (ASIRs) and age-standardized mortality rates were investigated using the 2000 mid-year estimated population aged over 20 years and older. A joinpoint regression model was used to determine the 2020 to 2035 trends in cancer. Results: Overall, cancer cases were predicted to increase from 265 299 in 2020 to 474 085 in 2035 (growth rate: 1.8%). The greatest increase in the ASIR was projected for prostate cancer among male (7.84 vs. 189.53 per 100 000 people) and breast cancer among female (34.17 vs. 238.45 per 100 000 people) from 2000 to 2035. Overall cancer deaths were projected to increase from 81 717 in 2020 to 95 845 in 2035 (average annual growth rate: 1.2%). Although most cancer mortality rates were projected to decrease, those of breast, pancreatic, and ovarian cancer among female were projected to increase until 2035. Conclusions: These up-to-date projections of cancer incidence and mortality in the Korean population may be a significant resource for implementing cancer-related regulations or developing cancer treatments

Conceptual Retrieval based on Feature Clustering of Documents

In the Web search, since users' queries usually consist of only a few words, it is hard to identify their information needs. To solve this problem, many approaches have tried to expand initial queries and to reweight the terms in the expanded queries using users' relevance judgments. Although relevance feedback is most effective when relevance information about retrieved documents is provided by users, it is not a fully automatic method. Another solution is to use correlated terms for query expansion. The main problem with this approach is how to construct the term-term correlations that can be used effectively to improve retrieval performance. In this study, we try to construct query concepts that denote users' information needs from a document space, rather than to reformulate initial queries using the term correlations and/or users' relevance feedback. To make query concepts, we extract features from each document, and cluster the features into primitive concepts that are used to form query concepts. Experiment is performed on a TREC collection

Association of the Vitamin D Level and Quality of School Life in Adolescents with Irritable Bowel Syndrome

There is no treatment of choice for irritable bowel syndrome, which affects up to 20% of school-aged children. This cross-sectional study evaluated the difference in the average vitamin D level between subtypes of irritable bowel syndrome, and the relationship between the vitamin D level as well as the severity of irritable bowel syndrome symptoms. We included 124 adolescents aged 10⁻17 years (68 boys, 56 girls; mean age 12.29 ± 1.92 years) from 2014 to 2016. Patients with irritable bowel syndrome were diagnosed by Rome III criteria and classified by clinical manifestation: irritable bowel syndrome with constipation (n = 29), irritable bowel syndrome with diarrhea (n = 63), and irritable bowel syndrome with constipation and diarrhea (n = 32). The severity of irritable bowel syndrome symptoms and school absence were evaluated. Vitamin D levels were measured by serum 25-hydroxyvitamin D. The chi-square test and analysis of variance were used. The patients’ average vitamin D level was 16.25 ± 6.58 ng/mL. There was a significant negative association of the 25-hydroxyvitamin D level with symptom severity and school absence (p = 0.022 and p < 0.001, respectively). Vitamin D supplementation could be considered as a choice of therapeutic method

Internal-specific morphological analysis of sciatic nerve fibers in a radiofrequency-induced animal neuropathic pain model.

This study investigated the reversible effects of pulsed radiofrequency (PRF) treatment at 42 °C on the ultrastructural and biological changes in nerve and collagen fibers in the progression of neuropathic pain after rat sciatic nerve injury. Assessments of morphological changes in the extracellular matrices by atomic force microscopy and hematoxylin-eosin, Masson's trichrome and picrosirius-red staining as well as the expressions of two fibril-forming collagens, types-I and -III, and two inflammatory cytokines, TNF-α and IL-6, were evaluated on day 30 after RF exposure. There were four groups for different RF thermal treatments: no treatment, no current, PRF, and continuous RF (CRF). An RF procedure similar to that used in human clinical trials was used in this study. The CRF treatment at 82 °C led to neural and collagen damage by the permanent blockage of sensory nociceptors. The PRF treatment led to excellent performance and high expandability compared to CRF, with effects including slight damage and swelling of myelinated axons, a slightly decreased amount of collagen fibers, swelling of collagen fibril diameters, decreased immunoreactivity of collagen types-I and -III, presence of newly synthesized collagen, and recovery of inflammatory protein immunoreactivity. These evidence-based findings suggest that PRF-based pain relief is responsible for the temporary blockage of nerve signals as well as the preferential destruction of pain-related principal sensory fibers like the Aδ and C fibers. This suggestion can be supported by the interaction between the PRF-induced electromagnetic field and cell membranes; therefore, PRF treatment provides pain relief while allowing retention of some tactile sensation