Essays on Macroeconomics and Labor Markets: Understanding Idiosyncratic and Aggregate Shocks

This dissertation studies the importance of shocks in understanding economic outcomes, both at the aggregate and at the individual levels. The research in this document is separated into chapters that deal with somewhat dissimilar questions which are linked by the necessity to acknowledge and understand how unforeseeable shocks determine how agents make economic decisions. These shocks or innovations are a potential explanation for why, often similar economic actors face very different paths. In Chapter 2, the interest lays in the determinants of different life-cycle fertility outcomes across educational groups. The chapter presents a model where individuals deal with idiosyncratic shocks in the form of innovations to their market wages and to the efficacy with which they can control fertility outcomes. The model is estimated using data for the US and tested to see how it fares replicating facts of aggregate fertility under different counterfactual scenarios. Chapter 3 (co-authored with Jose-Victor Rios-Rull), studies the cyclical behavior of the aggregate labor\u27s share in total income, taking as a starting point models of business cycles driven by economy-wide technological shocks. The chapter looks at the co-movement of labor share and technological innovations in post war US history and assesses how well existing models can explain the facts

El Dinero como Indicador Líder

For policy makers and business cycles analysts is important to count on variables that anticipate points of inflection in economic activity. This paper studies aggregate real money balances as leader indicator of the economic activity based on a Probit moMoney, leading indicator, probit model, granger-type casuality tests, cointegration

A note on U.S. worker turnover

The length of new employment relationships is of first-order importance for a number of questions in recent macro-labour research. We investigate it using data from the Survey of Income and Program Participation for the US from 1996 onwards, and document that above two-fifths of newly employed workers fall into non-employment within a year. We also find that the transition rate from employment to non-employment within the first year varies significantly for different groups of the population, increases with the duration of the previous non-employment spell, exhibits an acyclical or weakly procyclical pattern and a much higher volatility than the unemployment rate

Gas-Filled Phospholipid Nanoparticles Conjugated with Gadolinium Play a Role as a Potential Theragnostics for MR-Guided HIFU Ablation

To develop a long-circulating theragnostics, meaning therapeutics and diagnostics for MR-guided HIFU ablation, we designed and prepared Gd-C5F12-phospholipid nanobubbles (PLNs) 30–100 nm in diameter. The biochemical and physical characterization of Gd-C5F12-PLNs were performed. Since Gd-C5F12-PLN-50 (Φ = 50 nm) and Gd-C5F12-PLN-100 (Φ = 100 nm) enhanced the hyperthermal effect of HIFU size- and concentration-dependently in a tissue-mimicking phantom, its circulation, distribution, tumor accumulation and tumor ablation were examined in tumor-bearing mice. The plasma-half life of Gd-C5F12-PLNs was longer than 1.5 hrs. Gd-C5F12-PLNs mainly accumulated in the liver and the spleen, suggesting that they are slowly secreted through the hepatobiliary pathway. Monitored by the T1 signal intensity of MR, Gd-C5F12-PLNs accumulated in tumor tissues for 8 hours in mice. HIFU with Gd-C5F12-PLN-100 showed the increased tumor ablation area as compared with HIFU alone. The results suggest that Gd-C5F12-PLNs exhibit a potential theragnostics for MR-guided HIFU ablation

Auricular Cartilage Regeneration with Adipose-Derived Stem Cells in Rabbits

Tissue engineering cell-based therapy using induced pluripotent stem cells and adipose-derived stem cells (ASCs) may be promising tools for therapeutic applications in tissue engineering because of their abundance, relatively easy harvesting, and high proliferation potential. The purpose of this study was to investigate whether ASCs can promote the auricular cartilage regeneration in the rabbit. In order to assess their differentiation ability, ASCs were injected into the midportion of a surgically created auricular cartilage defect in the rabbit. Control group was injected with normal saline. After 1 month, the resected auricles were examined histopathologically and immunohistochemically. The expression of collagen type II and transforming growth factor-β1 (TGF-β1) were analyzed by quantitative polymerase chain reaction. Histopathology showed islands of new cartilage formation at the site of the surgically induced defect in the ASC group. Furthermore, Masson’s trichrome staining and immunohistochemistry for S-100 showed numerous positive chondroblasts. The expression of collagen type II and TGF-β1 were significantly higher in the ASCs than in the control group. In conclusion, ASCs have regenerative effects on the auricular cartilage defect of the rabbit. These effects would be expected to contribute significantly to the regeneration of damaged cartilage tissue in vivo

Evaluation of the pathogenicity of GJB3 and GJB6 variants associated with nonsyndromic hearing loss

AbstractA number of genes responsible for hearing loss are related to ion recycling and homeostasis in the inner ear. Connexins (Cx26 encoded by GJB2, Cx31 encoded by GJB3 and Cx30 encoded by GJB6) are core components of gap junctions in the inner ear. Gap junctions are intercellular communication channels and important factors that are associated with hearing loss. To date, a molecular genetics study of GJB3 and GJB6 as a causative gene for hearing loss has not been performed in Korea. This study was therefore performed to elucidate the genetic characteristics of Korean patients with nonsyndromic sensorineural hearing loss and to determine the pathological mechanism of hearing loss by analyzing the intercellular communication function of Cx30 and Cx31 variants. Sequencing analysis of the GJB3 and GJB6 genes in our population revealed a total of nine variants, including four novel variants in the two genes. Three of the novel variants (Cx31-p.V27M, Cx31-p.V43M and Cx-30-p.I248V) and two previously reported variants (Cx31-p.V84I and Cx30-p.A40V) were selected for functional studies using a pathogenicity prediction program and assessed for whether the mutations were located in a conserved region of the protein. The results of biochemical and ionic coupling tests showed that both the Cx31-p.V27M and Cx31-p.V84I variants did not function normally when each was expressed as a heterozygote with the wild-type Cx31. This study demonstrated that two variants of Cx31 were pathogenic mutations with deleterious effect. This information will be valuable in understanding the pathogenic role of GJB3 and GJB6 mutations associated with hearing loss