Essays on Technology Adoption, Demographics, and Development

This dissertation is to connect empirical findings with grounded theoretical analysis on two economic issues. One of the studies investigates industrial productivity by fitting in a theoretical model with quantitative methods. In addition, I explore how a demographic policy in China brings forth a profound impact in all aspects of the fast-growing economy. The first chapter, ``Casual Labor, Uncertainty, and Technology Adoption in Agriculture, examines why both the technology adoption rate and labor productivity in agriculture are low in the context of developing countries. A two-stage model is built to explain how the availability of casual (non-permanent) labor ex-post, in the presence of uncertainty may affect agents\u27 ex-ante technology choices. A higher degree of uncertainty induces the agents to choose traditional production technology that relies heavily on the labor input instead of using any modern intermediate inputs. By calibrating the model to fit the micro data in Tanzania, I show that this proposed framework can be used to account for two targets of interest: low aggregate labor productivity and the low technology adoption rate. Counterfactual exercises suggest that the severity of uncertainty before the harvest stage and the abundance of casual labor are the potential drivers for the two targets to be explained. The second chapter, ``Growth in a Patrilocal Economy: Female Schooling, Household Savings, and China\u27s One-Child Policy, is co-authored Wei-Cheng Chen. We develop a model of parental education decision to analyze how a population control policy affects saving and schooling in a patrilocal society, where sons are responsible to support aged parents more than daughters. Parent\u27s investment in education depends on the degree of parental altruism and the need for old-age security. A tightened population control policy makes parental altruism more important relative to the security motive and shortens gender gap in education. We also take another crucial intergenerational incentive for daughter\u27s education into account, since lower fertility promotes female labor market participation and increases the value of female education. Our model explains why the Chinese economy under the ``One-Child Policy\u27\u27 exhibits a rapid growth of relative female schooling. Moreover, this chapter also articulates the relationship between household savings and demographic changes based on a general equilibrium analysis, which has been discussed extensively in recent years to explain the China\u27s saving puzzle

Controlled Heterogeneous Nucleation and Growth of Germanium Quantum Dots on Nanopatterned Silicon Dioxide and Silicon Nitride Substrates

Controlled heterogeneous nucleation and growth of Ge quantum dots (QDs) are demonstrated on SiO_2/Si_3N_4 substrates by means of a novel fabrication process of thermally oxidizing nanopatterned SiGe layers. The otherwise random self-assembly process for QDs is shown to be strongly influenced by the nanopatterning in determining both the location and size of the QDs. Ostwald ripening processes are observed under further annealing at the oxidation temperature. Both nanopattern oxidation and Ostwald ripening offer additional mechanisms for lithography for controlling the size and placement of the QDs

Enhanced Distillation Under Infrared Characteristic Radiation

This chapter introduces quasi-steady water vaporization under mid-infrared (IR) radiation and the IR absorption of characteristic radiation associated with the first-kind liquid-gaseous phase transition of water. When characteristic radiation in the mid-IR spectral range is applied to water surface, the strong volumetric absorption of radiation energy in the liquid-phase causes water to be nearly isothermal. In addition to volumetric absorption, surface absorption of characteristic radiation induces vaporization of water. The complete mechanism of liquid-gaseous phase-transition radiation involves the direct surface absorption/emission of infrared energy accompanied by evaporation/condensation of water. A direct consequence of excess characteristic radiation upon water surface is the induced supersaturation. This mechanism opens up a door for enhanced distillation under characteristic radiation. Blackbody-like materials such as black anodized aluminum surfaces and metal surfaces painted in black are recommended to be heated to ~250°C to serve as economical radiation sources. For isothermal water at room temperatures, ~20% supersaturation can be induced by hemispherical Blackbody radiation with temperature ~11°C higher than the water temperature. In this situation, energy extracted from the ambient for water vaporization can be as much as 80% of latent heat. With radiation-enhanced evaporation, the production cost for distilled water is significantly reduced as compared to distillation at the boiling point

The Division of Temporary and Permanent Employment and Business Cycle Fluctuations

This paper investigates the fluctuations in temporary relative to aggregate employment over the business cycle, as well as the underlying driving forces. We develop a dynamic general equilibrium model to investigate the following stylized facts: (i) temporary employment is more volatile than permanent employment, (ii) the share of temporary employment (the ratio of temporary to aggregate employment) exhibits strong pro-cyclicality, (iii) permanent employment lags by two quarters on average, and (iv) the correlation between temporary employment and output is stronger than that involving the permanent counterpart. The quantitative analysis suggests that the proposed channels explain the main facts very well and the model provides a possible prediction based on the counter-factual exercises

The Division of Temporary and Permanent Employment and Business Cycle Fluctuations

This paper investigates the fluctuations in temporary relative to aggregate employment over the business cycle, as well as the underlying driving forces. We develop a dynamic general equilibrium model to investigate the following stylized facts: (i) temporary employment is more volatile than permanent employment, (ii) the share of temporary employment (the ratio of temporary to aggregate employment) exhibits strong pro-cyclicality, (iii) permanent employment lags by two quarters on average, and (iv) the correlation between temporary employment and output is stronger than that involving the permanent counterpart. The quantitative analysis suggests that the proposed channels explain the main facts very well and the model provides a possible prediction based on the counter-factual exercises

Comparison of the safety and efficacy of a fixed-dose combination regimen and separate formulations for pulmonary tuberculosis treatment

OBJECTIVES: Fixed-dose combination formulations, which simplify the administration of drugs and prevent the development of drug resistance, have been recommended as a standard anti-tuberculosis treatment regimen. However, the composition and dosage recommendations for fixed-dose combination formulations differ from those for separate formulations. Thus, questions about the effectiveness and side effects of combination formulations remain. The aim of this study was to compare the safety and efficacy of these two types of anti-tuberculosis regimens for pulmonary tuberculosis treatment. METHOD: A prospective, randomized controlled study was conducted using the directly observed treatment short-course strategy. Patients were randomly allocated to one of two short-course regimens. One year after completing the treatment, these patients’ outcomes were analyzed. ClinicalTrials.gov: NCT00979290. RESULTS: A total of 161 patients were enrolled, 142 of whom were evaluable for safety assessment. The two regimens had a similar incidence of adverse effects. In the per-protocol population, serum bilirubin concentrations at the peak level, at week 4, and at week 8 were significantly higher for the fixed-dose combination formulation than for the separate formulations. All patients had negative sputum cultures at the end of the treatment, and no relapse occurred after one year of follow-up. CONCLUSIONS: In this randomized study, transient higher serum bilirubin levels were noted for the fixed-dose combination regimen compared with the separate formulations during treatment. However, no significant difference in safety or efficacy was found between the groups when the directly observed treatment short-course strategy was used

Application of Head-up Tilt Table Testing in Children

Background/PurposeWe investigated the application of head-up tilt table testing (HUT) and management of neurocardiogenic syncope (NCS) in children, as pediatric studies are limited.MethodsSeventy-nine patients (ages 6-18 years) underwent HUT for evaluation of syncope. Patient triggers and premonitory symptoms allowed the clinical diagnosis of NCS or non-NCS. Results were divided into four hemodynamic types (1, 2A, 2B, and 3) according to patient response to HUT.ResultsNCS occurred in 65 patients and non-NCS in 14 patients. Isoproterenol infusion significantly increased the sensitivity of the test (from 28% to 45%) and was associated with a slight decrease in the specificity (from 93% to 86%). Subjects in the type 1 group accounted for the majority of responses to the test (69%). There were no complications associated with the test. At follow-up (16.6 ± 9.3 months), the overall recurrence rate was 30.8% but NCS was less severe in most patients. The recurrence rate was similar for patients with a positive or negative HUT and for both pharmacologically and non-pharmacologically treated patients.ConclusionHUT can be safely performed with a high specificity in children, with the sensitivity of HUT improved by isoproterenol. Therefore, a positive response to treatment is reassuring to the physician and family. NCS is generally a self-limited condition despite a high recurrence rate

Retraction and Generalized Extension of Computing with Words

Fuzzy automata, whose input alphabet is a set of numbers or symbols, are a formal model of computing with values. Motivated by Zadeh's paradigm of computing with words rather than numbers, Ying proposed a kind of fuzzy automata, whose input alphabet consists of all fuzzy subsets of a set of symbols, as a formal model of computing with all words. In this paper, we introduce a somewhat general formal model of computing with (some special) words. The new features of the model are that the input alphabet only comprises some (not necessarily all) fuzzy subsets of a set of symbols and the fuzzy transition function can be specified arbitrarily. By employing the methodology of fuzzy control, we establish a retraction principle from computing with words to computing with values for handling crisp inputs and a generalized extension principle from computing with words to computing with all words for handling fuzzy inputs. These principles show that computing with values and computing with all words can be respectively implemented by computing with words. Some algebraic properties of retractions and generalized extensions are addressed as well.Comment: 13 double column pages; 3 figures; to be published in the IEEE Transactions on Fuzzy System