Three Essays on the Economics of the Family

August 2017 ABSTRACT THREE ESSAYS ON THE ECONOMICS OF THE FAMILY by Mehrnoush Motamedi The University of Wisconsin-Milwaukee, 2017 Under the Supervision of Professor Scott Adams The goal of this dissertation is to apply empirical methodologies to analyze various topics in economics of education and health economics, which have clear policy implications. Chapter 1 presents evidence of heterogeneous labor market returns for children depending on the time intervals between sibling births. My empirical strategy exploits exogenous variation in child spacing stemming from whether there are twins in the family and an age difference between the mother and the father. Results show significant negative effects of spacing in children from well-resourced families, but I observe positive and insignificant effects of birth spacing on children’s labor market earnings in the lower stratum. Chapter 2 provides evidence of whether child spacing affects the likelihood of engaging in certain risky behaviors. Using data from the National Longitudinal Survey of Youth–1979, I investigate the association between birth spacing and engaging in risky or deviant behaviors, such as smoking, unprotected intercourse, theft, and violence. I attempt to identify exogenous variation in in child spacing stemming from whether one has a twin and parents’ age difference, and my estimates show significant declines in engaging in risky behaviors for all these four risky activities as birth spacing increases. In chapter 3 despite being widely accepted as a behavior damaging to one’s future, we show that among girls engaging in sex while a teenager likely has no long-term economic consequences in terms of labor market earnings. In fact, once we control for teen childbearing and educational attainment, it is significantly correlated with positive earnings. The substantial positive outcomes appear to be concentrated among girls from higher socioeconomic strata, with little significant effects among those from less advantaged backgrounds. Only a small part of this difference seems to be explained by lower birth rates among the sexually active in higher socioeconomic strata. This leaves most due to either a causal effect of teenage sexual activity, which is unlikely, or the result of unobserved characteristics (to the researchers) among those from higher socioeconomic strata who are sexually active during adolescence. From a policy standpoint, these findings suggest that promoting teenage abstinence by touting long-term economic benefits may be misguided, particularly for those ages 15-17

Prostate Tumor Volume Measurement on Digital Histopathology and Magnetic Resonance Imaging

An accurate assessment of prostate tumour burden supports appropriate treatment selection, ranging from active surveillance through focal therapy, to radical whole-prostate therapies. For selected patients, knowledge of the three-dimensional locations and sizes of prostate tumours on pre-procedural imaging supports planning of effective focal therapies that preferentially target tumours, while sparing surrounding healthy tissue. In the post-prostatectomy context, pathologic measurement of tumour burden in the surgical specimen may be an independent prognostic factor determining the need for potentially life-saving adjuvant therapy. An accurate and repeatable method for tumour volume assessment based on histology sections taken from the surgical specimen would be supportive both to the clinical workflow in the post-prostatectomy setting and to imaging validation studies correlating tumour burden measurements on pre-prostatectomy imaging with reference standard histologic tumour volume measurements. Digital histopathology imaging is enabling a transition to a more objective quantification of some surgical pathology assessments, such as tumour volume, that are currently visually estimated by pathologists and subject to inter-observer variability. Histologic tumour volume measurement is challenged by the traditional 3–5 mm sparse spacing of images acquired from sections of radical prostatectomy specimens. Tumour volume estimates may benefit from a well-motivated approach to inter-slide tumour boundary interpolation that crosses these large gaps in a smooth fashion. This thesis describes a new level set-based shape interpolation method that reconstructs smooth 3D shapes based on arbitrary 2D tumour contours on digital histology slides. We measured the accuracy of this approach and used it as a reference standard against which to compare previous approaches in the literature that are simpler to implement in a clinical workflow, with the aim of determining a method for histologic tumour volume estimation that is both accurate and amenable to widespread implementation. We also measured the effect of decreasing inter-slide spacing on the repeatability of histologic tumour volume estimation. Furthermore, we used this histologic reference standard for tumour volume to measure the accuracy, inter-observer variability, and inter-sequence variability of prostate tumour volume estimation based on radiologists’ contouring of multi-parametric magnetic resonance imaging (MPMRI). Our key findings were that (1) simple approaches to histologic tumour volume estimation that are based on 2- or 3-dimensional linear tumour measurements are more accurate than those based on 1-dimensional measurements; (2) although tumour shapes produced by smooth through-slide interpolation are qualitatively substantially different from those obtained from a planimetric approach normally used as a reference standard for histologic tumour volume, the volumes obtained were similar; (3) decreasing inter-slide spacing increases repeatability of histologic tumour volume estimates, and this repeatability decreases rapidly for inter-slide spacing values greater than 5 mm; (4) on MPMRI, observers consistently overestimated tumour volume as compared to the histologic reference standard; and (5) inter-sequence variability in MPMRI-based tumour volume estimation exceeded inter-observer variability

Mapping Persian Words to WordNet Synsets

Lexical ontologies are one of the main resources for developing natural language processing and semantic web applications. Mapping lexical ontologies of different languages is very important for inter-lingual tasks. On the other hand mapping approaches can be implied to build lexical ontologies for a new language based on pre-existing resources of other languages. In this paper we propose a semantic approach for mapping Persian words to Princeton WordNet Synsets. As there is no lexical ontology for Persian, our approach helps not only in building one for this language but also enables semantic web applications on Persian documents. To do the mapping, we calculate the similarity of Persian words and English synsets using their features such as super-classes and subclasses, domain and related words. Our approach is an improvement of an existing one applying in a new domain, which increases the recall noticeably