Essays in Macroeconomics

Thesis advisor: Fabio GhironiChapter 1: Foreign Direct Investment and Contract Enforcement Many developing countries are financially constrained and therefore have to rely on international capital flows to finance economic activity. Empirical evidence shows that Foreign Direct Investment (FDI) as a percentage of total capital flows is higher for less developed countries compared to more developed countries. This chapteruses a dynamic contracting model with human capital to explain why less developed countries receive a greater percentage of capital flows as FDI. I analytically show that countries that are financially constrained have a higher share of FDI in total capital flows, and that the share of FDI in total capital flows is increasing in human capital flows. In addition, the positive association between the share of FDI in total capital flows and human capital flows is decreasing in the degree of financial constraints. I construct a measure of intangible assets of FDI and find empirical support for the analytical results. Chapter 2: Trade Liberalization, Firm Heterogeneity, and Unemployment: An Empirical Investigation This chapter is a joint work with Yoto V. Yotov. We provide empirical evidence for the interaction between firm-level total factor productivity and trade liberalization as key determinants of firm-level job destruction caused by trade. Employing US firm-level data, we find strong empirical support for the following: a) All else equal, a one percent increase in total factor firm productivity decreases trade-induced layoffs by 32%; b) An additional percent of trade liberalization increases the number of firm-level trade-induced layoffs by 2%; c) Trade liberalization results in an increase in the minimum level of productivity required for domestic production; d) Trade liberalization lowers the minimum productivity threshold required for exporting; e) The increase due to trade liberalization in the minimum productivity threshold for domestic production is larger than the absolute decrease in the export productivity threshold. Chapter 3: Do Audit Fees Influence Credit Risk and Asymmetric Information Problems? Evidence from the Syndicated Loan Market This chapter is a joint work with Lewis W. Gaul. We examine whether an increase in the demand for auditing services is associated with a decrease in borrowers' credit risk and asymmetric information problems in the syndicated loan market. In the syndicated loan market, potential accounting errors exacerbate credit risk and asymmetric information problems. The purpose of financial statement audits is to provide reasonable assurance that accounting records are free from material errors. We hypothesize that if audit fees face an upward sloping supply curve for auditing services, an increase in the demand for auditing services increases both the equilibrium price and quantity of auditing services purchased. We interpret the equilibrium quantity of auditing services as the number of auditing hours billed and the price of auditing services as the hourly fee. We assert that an increase in the quantity of auditing services purchased reduces the likelihood of an accounting error because auditors exert more effort verifying the accuracy of accounting records. We present empirical evidence that a demand-induced increase in audit fees is associated with syndicated loans with lower interest rate spreads and shorter maturity lengths, which we interpret as evidence consistent with the assertion that these audit fee increases reduce credit-risk and asymmetric information problems. We empirically identify an increase in the demand for auditing services with instrumental variables that are intended to capture shifts in the demand curve for auditing services, rather than shifts in the supply curve for auditing services. In addition, we find that audit fees are positively associated with the number of lenders in loan syndicates, but are unable to attribute this association to an increase in the demand for auditing services.Thesis (PhD) — Boston College, 2009.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: Economics

Epidermal growth factor potentiates in vitro metastatic behaviour of human prostate cancer PC-3M cells: involvement of voltage-gated sodium channel

<p>Abstract</p> <p>Background</p> <p>Although a high level of functional voltage-gated sodium channel (VGSC) expression has been found in strongly metastatic human and rat prostate cancer (PCa) cells, the mechanism(s) responsible for the upregulation is unknown. The concentration of epidermal growth factor (EGF), a modulator of ion channels, in the body is highest in prostatic fluid. Thus, EGF could be involved in the VGSC upregulation in PCa. The effects of EGF on VGSC expression in the highly metastatic human PCa PC-3M cell line, which was shown previously to express both functional VGSCs and EGF receptors, were investigated. A quantitative approach, from gene level to cell behaviour, was used. mRNA levels were determined by real-time PCR. Protein expression was studied by Western blots and immunocytochemistry and digital image analysis. Functional assays involved measurements of transverse migration, endocytic membrane activity and Matrigel invasion.</p> <p>Results</p> <p>Exogenous EGF enhanced the cells' <it>in vitro </it>metastatic behaviours (migration, endocytosis and invasion). Endogenous EGF had a similar involvement. EGF increased VGSC Nav1.7 (predominant isoform in PCa) mRNA and protein expressions. Co-application of the highly specific VGSC blocker tetrodotoxin (TTX) suppressed the effect of EGF on all three metastatic cell behaviours studied.</p> <p>Conclusion</p> <p>1) EGF has a major involvement in the upregulation of functional VGSC expression in human PCa PC-3M cells. (2) VGSC activity has a significant intermediary role in potentiating effect of EGF in human PCa.</p

Can Equity Volatility Explain the Global Loan Pricing Puzzle?

We examine whether equity volatility can explain the difference in syndicated corporate loan spreads paid by U.S. and European borrowers first documented by Carey and Nini (2007). We argue that OLS estimates of the association between equity volatility and loan spreads are biased and inconsistent. We suggest instrumental variables that potentially identify consistent estimates. Our instrumental variable results indicate that there is no statistically significant difference in loan spreads paid by U.S. and European borrowers, and that OLS estimates of the association between idiosyncratic equity volatility and corporate loan spreads are biased downward by about a factor of 5

Trade Liberalization, Firm Heterogeneity, and Labor Layoffs: An Empirical Investigation

This is the first empirical attempt to provide evidence for the interaction between firm-level total factor productivity and trade liberalization as key determinants of firm-level job destruction caused by trade. Employing an original US firm-level data, we test and find support for theoretical predictions from Melitz (2003), whose model we use to derive an explicit equation relating firm productivity and trade-induced layoffs when a country liberalizes its trade policy. In addition, we incorporate intuitive labor market interactions that are not explicitly captured in Melitz's model. These allow us to reconcile some discrepancies between theory and empirical work

Mycosis fungoides and vitamin D status: Analyses of serum 25-hidroxyvitamin D levels and single nucleotide polymorphisms in the vitamin D receptor gene

Various types of cancer, including melanoma and non-melanoma skin cancer, are associated with vitamin D receptor (VDR) polymorphisms. However, few studies have addressed VDR polymorphisms in patients with mycosis fungoides (MF), and previous studies have reported conflicting results. Aim of this case-control study was to assess the correlation between VDR single nucleotide polymorphisms (SNPs) Cdx2, Fok1, Apa1, Bsm1, and Taq1 and MF. Venous blood samples were collected from 41 patients with MF and 59 age- and sex-matched healthy controls. VDR genotypes of both groups were analyzed. Serum vitamin D levels of patients with MF were also analysed among varying stages and VDR genotypes. Vitamin D levels were significantly low (&lt;30 ng/mL) in 87.9% of the patients (P&lt;0.001). No associations were found between Apa1, Cdx2, Fok1, and Bsm1 SNPs and MF. However, Taq1 polymorphisms were higher in the healthy control group (P&lt;0.001). Our study supports the claim that vitamin D deficiency is common in patients with MF. On the other hand, our findings suggest that Taq1 polymorphisms may be associated with decreased susceptibility to MF. Therefore, VDRs may have complex and heterogeneous effects on the pathogenesis of MF. </p

Mycosis fungoides and vitamin D status: Analyses of serum 25-hidroxyvitamin D levels and single nucleotide polymorphisms in the vitamin D receptor gene

Various types of cancer, including melanoma and non-melanoma skin cancer, are associated with vitamin D receptor (VDR) polymorphisms. However, few studies have addressed VDR polymorphisms in patients with mycosis fungoides (MF), and previous studies have reported conflicting results. Aim of this case-control study was to assess the correlation between VDR single nucleotide polymorphisms (SNPs) Cdx2, Fok1, Apa1, Bsm1, and Taq1 and MF. Venous blood samples were collected from 41 patients with MF and 59 age- and sex-matched healthy controls. VDR genotypes of both groups were analyzed. Serum vitamin D levels of patients with MF were also analysed among varying stages and VDR genotypes. Vitamin D levels were significantly low (&lt;30 ng/mL) in 87.9% of the patients (P&lt;0.001). No associations were found between Apa1, Cdx2, Fok1, and Bsm1 SNPs and MF. However, Taq1 polymorphisms were higher in the healthy control group (P&lt;0.001). Our study supports the claim that vitamin D deficiency is common in patients with MF. On the other hand, our findings suggest that Taq1 polymorphisms may be associated with decreased susceptibility to MF. Therefore, VDRs may have complex and heterogeneous effects on the pathogenesis of MF. </p

Mortgage Default in an Estimated Model of the U.S. Housing Market

This paper models the housing sector, mortgages and endogenous default in a DSGE setting with nominal and real rigidities. We use data for the period 1981-2006 to estimate our model using Bayesian techniques. We analyze how an increase in risk in the mortgage market raises the default rate and spreads to the rest of the economy, creating a recession. In our model two shocks are well suited to replicate the subprime crisis and the Great Recession: the mortgage risk shock and the housing demand shock. Next we use our estimated model to evaluate a policy that reduces the principal of underwater mortgages. This policy is successful in stabilizing the mortgage market and makes all agents better off. (C) 2017 Elsevier B.V. All rights reserved

Evaluation of the importance of immunological profile for pemphigus vulgaris in the light of necessity to modify compensation theory

According to the “desmoglein compensation theory,” anti-Dsg1 and anti-Dsg3 profiles are crucial for the clinical outcome of pemphigus vulgaris. However, recent studies have highlighted several cases with an incompatibility between the antibody profile and clinical manifestation. Data of 37 patients who had been diagnosed pemphigus vulgaris in our Department between January 2014-June 2016 were retrieved from our clinical database. Patients with ABSIS skin involvement scores, oral mucosa extent and severity scores, anti-Dsg1 and Dsg3 antibody profile were included in this retrospective study. Patients with discordance between clinical manifestations and immunological profile were considered as atypical clinical phenotype. Patients with missing data were excluded. In all 37 patients, Dsg1 and Dsg3 antibody titers at the baseline did not correlate with the concurrent ABSIS scores. At follow up, we detected statistically significant correlations between anti Dsg-1 profile and ABSIS skin involvement scores (p=0.006; r=0.588) and between anti-Dsg3 and ABSIS mucosal extent and severity scores (p=0.058; r=0.431). After treatment, the reduction of Dsg-1 antibody titers was statistically significant in remittent patients (p=0.027). We did not detect statistically significant reduction of Dsg-3 antibodies. Four subjects had incompatible antibody profile and clinical activity. Discordance between phenotype-antibody profile and clinical activity-Dsg titers support the idea that non-Dsg antigens may also be the target for pemphigus autoimmunity. </p