Essays on Sovereign Debt Crisis

This thesis consists of three chapters that aim to develop economic models to explain sovereign debt crises. Chapter 2 provides the dynamic general equilibrium model of endogenous sovereign default, incorporating financial intermediaries. By a government's decision to default, government bonds become non-performing and financial intermediaries eliminate them from their net worth. While other literature on endogenous default models assumes that the default state is exogenously given, only depending on TFP or endowment, the model in Chapter 2 creates a mechanism by which the default state is contingent on the amount of debt outstanding in the non-default state. Through this feature, the model quantifies the financial amplification effect on the economy and shows the phenomenon of "Too-Big-to-Default". The model explains the important features of the Argentinean default in 2001, capturing the default frequency, the debt-to-GDP ratio and moments of main variables. Chapter 3 proposes a new sovereign debt crisis model which is applicable to an advanced country, assuming the government's incapability to serve its debts rather than willingness of repayment. The fiscal limit is defined as the sum of discounted future primary surplus under the tax rate to maximize tax revenue. When the debt outstanding exceeds the fiscal limit, the government falls into debt crisis. The economic contraction in the crisis results from the exogenous tax rate and decreased imported inputs. The model replicates the high debt-to-GDP ratio, which the endogenous model cannot assume, and captures movements of important variables of the Spanish debt crisis in around 2012. Chapter 4 introduce foreign bonds based on the model in Chapter 3, for the analysis of several countries such as Greece and Ireland in which a majority of bonds is held by foreign agents. In the model, the government issues bonds for foreign investors, and that leads the outflow of domestic output. Instead of government bonds, households adopt capital for their inter-temporal utility maximization. Also, the fiscal limit is drawn from the exogenous distribution. The simulation result for the Greek economy generally explains the contraction of its economy by the crisis in around 2012 although the effect of imported inputs is overestimated and that of domestic inputs is underestimated

Contemporary Nigerian Sculpture: Where are the Flowers?

There is general assumption that flowers are Western not African. Mazrui et al (2004) opines that ‘there is a “floral gap” in African culture’. By this he refers to an insignificant representation of flowers in African Culture. This study investigates the possibilities of including flowers in contemporary sculpture as a way of bridging the floral gap. This study will not be sufficient to fill the floral gap but is aimed at promoting a flower culture in Nigeria.  It brings to fore the issues of extinction, adaptation and its Consequences. It emphasises the dire need for artists in Nigeria to respond to the environment and issues that pertain to her. Five flowers have been selected; hibiscus, lily, zinnia, sunflower and rose; they are explored to create sculptures in relief and round forms to satisfy the canons of representational and abstract art. The approach of this study is studio-experiment. The purpose of this research is to promote a flower culture in Nigeria, making flowers a relevant subject matter in expressing thoughts and ideas in art

Estimating the Effects of Regulating University Face-to-Face Lectures on the Spread of COVID-19: Evidence from Japan

※2022年5月改

N,N′-(2,2′-Dithiodi-o-phenyl­ene)bis­(furan-2-carboxamide)

The reaction of 2,2′-dithio­bis(benzenamine) with furan-2-carbonyl chloride produced the bis-amide title compound, C22H16N2O4S2, which, in the crystal, formed a helix; the structure consists of two planar furanoylbenzenamines related by an improper rotation of 96.3° about the S—S bond. The N-furanoylbenzenamine units are planar (maximum deviations = 0.316 and 0.132 Å). Each electron-deficient acyl­furan stacks (centroid–centroid separations of the two pairs of π–π stacked aromatic rings are 3.918 and 3.953 Å) with the electron-rich benzenamine of the other N-furan­oyl­benzenamine unit, leading to a spiral structure. The conformation is stabilized by two bifurcated intramolecular N—H⋯(O,S) interactions

Synthesis of perhydrofuro[2,3-b]furans from isopentenyl alcohol through carbonyl-ene and wacker-type reactions

A range of 2-substituted perhydrofuro[2,3-b]furans have been synthesized in a stereoselective manner through a sequence involving the Lewis-acid catalyzed carbonyl-ene reaction of a protected isopentenyl alcohol with a variety of enophiles, deprotection of the corresponding monoprotected diols, and palladium-catalyzed intramolecular acetalization under Wacker-type reaction conditions.This work was generously supported by the Spanish Ministerio de Ciencia e Innovación (MICINN), grant number CTQ2007-65218 and Consolider Ingenio 2010, grant number CSD2007-00006, the Generalitat Valenciana (GV; PROMETEO/2009/039), and Fondos Europeos para el Desarrollo Regional (FEDER). D. S. thanks the Vicerrectorado de Investigación, Desarrollo e Innovación of the Universidad de Alicante for a predoctoral grant. M. R.-F. thanks the ISO of the Universidad de Alicante for a postdoctoral grant

Ultra-Sensitive Mutation Detection and Genome-Wide DNA Copy Number Reconstruction by Error-Corrected Circulating Tumor DNA Sequencing.

Background Circulating free DNA sequencing (cfDNA-Seq) can portray cancer genome landscapes, but highly sensitive and specific technologies are necessary to accurately detect mutations with often low variant frequencies.Methods We developed a customizable hybrid-capture cfDNA-Seq technology using off-the-shelf molecular barcodes and a novel duplex DNA molecule identification tool for enhanced error correction.Results Modeling based on cfDNA yields from 58 patients showed that this technology, requiring 25 ng of cfDNA, could be applied to >95% of patients with metastatic colorectal cancer (mCRC). cfDNA-Seq of a 32-gene, 163.3-kbp target region detected 100% of single-nucleotide variants, with 0.15% variant frequency in spike-in experiments. Molecular barcode error correction reduced false-positive mutation calls by 97.5%. In 28 consecutively analyzed patients with mCRC, 80 out of 91 mutations previously detected by tumor tissue sequencing were called in the cfDNA. Call rates were similar for point mutations and indels. cfDNA-Seq identified typical mCRC driver mutations in patients in whom biopsy sequencing had failed or did not include key mCRC driver genes. Mutations only called in cfDNA but undetectable in matched biopsies included a subclonal resistance driver mutation to anti-EGFR antibodies in KRAS , parallel evolution of multiple PIK3CA mutations in 2 cases, and TP53 mutations originating from clonal hematopoiesis. Furthermore, cfDNA-Seq off-target read analysis allowed simultaneous genome-wide copy number profile reconstruction in 20 of 28 cases. Copy number profiles were validated by low-coverage whole-genome sequencing.Conclusions This error-corrected, ultradeep cfDNA-Seq technology with a customizable target region and publicly available bioinformatics tools enables broad insights into cancer genomes and evolution.Clinicaltrialsgov identifier NCT02112357