ESSAYS ON SOVEREIGN DEFAULT AND HOUSEHOLD PORTFOLIO CHOICE

This dissertation analyzes portfolio choice problems in different contexts. In the first chapter, “Nominal Exchange Rate Volatility, Default Risk and Reserve Accumulation,” I investigate how nominal exchange rate volatility affects a sovereign's portfolio choice between how much debt to acquire and how much reserves to accumulate. First, I document a positive correlation between nominal exchange rate volatility and sovereign default risk and show that this relationship becomes stronger when more of the external debt is denominated in foreign currency. Then, I build a sovereign default model to rationalize these findings and to quantify the channels that contribute to the large reserve holdings among emerging countries. In the second chapter, “Household Portfolio Accounting,” we document and analyze the substantial heterogeneity in household portfolio composition in the United States. We consider a standard life-cycle model with labor income risk and portfolio choice, augmented with a savings wedge that lowers the return on saving, and a risky wedge that lowers the relative return on risky assets. Using U.S. survey data (2004-2016), we compute the household-level wedges that rationalize the data. The chapter has two main contributions: first, it uses the wedges to guide plausible frictions that researchers should consider in their models. Second, it analyzes the extent to which household characteristics can account for the wedges

The Patterns of Parental Intervivos Transfers to Adult Children

This paper documents the patterns of total intervivos transfers adult children receive from their parents in the United States. Using 1996-2014 panel data from the Health and Retirement Study, our paper departs from the literature by following adult children over time and constructing measures of aggregated transfers received over different time horizons. We find that while the probability and transfer amount decrease as the child ages, conditional on receiving the age of the child is uncorrelated with transfer amounts. We characterize this lack of correlation as a result of parents following different transfer strategies, with some giving only early in the period, others giving only late, and others in both. Transfer strategies even vary within families, with some children receiving more generously and more consistently than others, even when controlling for children's income and age. Regarding total transfers over the 20-year sample period, we find that relative to their permanent income, poorer parents transfer more generously than high-income parents. Intervivos transfers are the predominant way in which adult children receive financial support from parents across the income distribution, in contrast with bequests which are received by a small fraction of children with high-income parents

All-pay contest : an experimental investigation

This paper experimentally investigates a special class of contests, “all-pay contests” (Siegel 2009), where economic agents are asymmetrically positioned and compete by making irreversible investments. We compare four treatments in a between-subject design, with a simple parameterization of Siegel’s all-pay contest model, to test the theoretical predictions. We find that, while the treatment effects are consistent with the theoretical prediction, average payoffs are significantly lower, and that Siegel's closed form formula is not fully sufficient to determine players’ equilibrium payoffs. Shape of the cost functions, players’ risk and social preferences, and the dynamic of the contest are the possible areas for further research.Bachelor of Art

The Full Recession: Private Versus Social Costs of Covid-19

Official recession figures ignore the costs associated with the loss of human life due to COVID-19. This paper constructs "full recession" measures that take into account the death toll. Key for the estimates are the number of dead, the individual's willingness to accept mortality risk, and society's willingness to accept inequality. Our model features tractable heterogeneity, constant relative risk aversion to mortality risk, and age-specific survival rates. Using an estimated death toll of 400 thousand people for the US during a year, and a baseline 10% recession, we find that the corresponding full recession is 26% on average across individuals, 17% for a median voter, 13% for a planner with mild aversion to inequality, and 19% for a planner with larger aversion. Regarding the overall cost of the pandemic, we find that individuals would be willing to pay, on average, 41% of one-year consumption to fully avoid the pre-lockdown 1.9 million deaths from COVID-19. A median voter would be willing to pay 23%, a social planner with mild aversion to inequality only 11%, while a log-planner would pay 73%.</p

Fluorescence Response Profiling for Small Molecule Sensors Utilizing the Green Fluorescent Protein Chromophore and Its Derivatives

Using a fluorescence response profile, a systematic examination was performed for synthetic chromophores of the green fluorescent protein (GFP) to discover new small molecule sensors. A group of 41 benzylideneimidazolinone compounds (BDI) was prepared and screened toward 94 biologically relevant analytes to generate fluorescence response profiles. From the response pattern, compounds containing aminobenzyl and heteroaromatic cyclic substructures revealed a pH dependent emission decrease effect, and unlike other fluorescence scaffolds, most BDIs showed fluorescence quenching when mixed with proteins. On the basis of the primary response profile, we obtained three selective fluorescence turn-on sensors for pH, human serum albumin (HSA), and total ribonucleic acid (RNA). Following analysis, a fluorescence response profile testing four nucleic acids revealed the alkyloxy (Ph-OR) functional group in the para position of benzyl analogues contributes to RNA selectivity. Among the primary hit compounds, BDI 2 showed outstanding selectivity toward total RNA with 5-fold emission enhancement. Finally, BDI 24 showed selective fluorescence increase to HSA (K(d) = 3.57 mu M) with a blue-shifted emission max wavelength (Delta lambda(em) = 15 nm). These examples of fluorescence sensor discovery by large-scale fluorescence response profiling demonstrate the general applicability of this approach and the usefulness of the response profiles.1129sciescopu

Epidemiological characteristics and molecular features of carbapenem-resistant Enterobacter strains in China: a multicenter genomic study

ABSTRACTEpidemiological characteristics and molecular features of carbapenem-resistant Enterobacter (CR-Ent) species remain unclear in China. In this study, we performed a genomic study on 92 isolates from Enterobacter-caused infections from a multicenter study in China. Whole genome sequencing (WGS) was used to determine the genome sequence of 92 non-duplicated CR-Ent strains collected from multiple tertiary health centres. The precise species of Enterobacter strains were identified by average nucleotide identity (ANI) and in silico DNA–DNA hybridization (isDDH). Molecular features of high-risk CR-Ent sequence type (ST) lineages and carbapenemase-encoding plasmids were determined. The result revealed that the most common human-source CR-Ent species in China was E. xiangfangensis (66/92, 71.93%), and the proportion of carbapenemase-producing Enterobacter (CP-Ent) in CR-Ent was high (72/92, 78.26%) in comparison to other global regions. Furthermore, ST171 and ST116 E. xiangfangensis were the major lineages of CP-Ent strains, and ST171 E. xiangfangensis was more likely to cause infections in older patients. Genomic analysis also highlighted the likelihood of intra-hospital/inter-hospital clonal transmission of ST171 and ST116 E. xiangfangensis. In addition, the blaNDM-harbouring IncX3-type plasmid was identified as the prevalent carbapenemase-encoding plasmid carried by CR-Ent strains, and was experimentally confirmed to be able to self-transfer with high frequency. This study detailed the genomic and clinical characteristics of CR-Ent in China in the form of multicenter for the first time. The high risk of carbapenemase-producing ST171 and ST116 E. xiangfangensis, and the blaNDM-harbouring IncX3-type plasmid were detected and emphasized