Lenstra-Hurwitz Cliques In Real Quadratic Fields

Let $K$ be a number field and let \OO_K denote its ring of integers. We can define a graph whose vertices are the elements of \OO_K such that an edge exists between two algebraic integers if their difference is in the units \OO_K^{\times}. Lenstra showed that the existence of a sufficiently large clique (complete subgraph) will imply that the ring \OO_K is Euclidean with respect to the field norm. A recent generalization of this work tells us that if we draw more edges in the graph, then a sufficiently large clique will imply the weaker (but still very interesting) conclusion that $K$ has class number one. This thesis aims to understand this new result and produce further examples of cliques in rings of integers. Lenstra, Long, and Thistlethwaite analyzed cliques and gave us class number one through a prime element. We were able to extend and generalize their result to larger cliques through prime power elements while still preserving our desired property of class number one. Our generalization gave us that class number one is preserved if the number field $K$ contained a clique that is generated by a prime power

U.S. Hispanic Country-of-Origin Counts for Nation, Top 30 Metropolitan Areas

Based on 2010 census data, summarizes trends in the countries of origin of Latinos/Hispanics compared with 2000, including the fastest-growing groups and their distribution across metropolitan areas

The Software and Information Services Sector in Argentina: Pros and Cons of an Inward-Orientated Development Strategy

software information services, developing countries, Argentina

Ignorance in Congressional Voting? Evidence from Policy Reversal on the Endangered Species Act

Objective: In 1978 Congress weakened several key provisions of the Endangered Species Act (ESA), which had been enacted only five years earlier. The objective is to compare alternative explanations for this policy reversal. Methods: Probit and multinomial logit models are used to explain empirically how senators voted in both 1973 and 1978, and to investigate why many senators switched their vote from supporting ESA to weakening it. Results: The findings here indicate that party affiliation and policymaker preferences were not important to the 1973 vote, but they were key variables in the 1978 votes and the vote-switching decision. Proxies for unexpected economic impacts of ESA on individual states have little explanatory power. Conclusions: Ignorance, as measured here, does not appear to explain this policy reversal. Rather, an influx of relatively conservative Democrats between 1973 and 1978 presents itself as the leading explanation.endangered species act, congressional voting

The Degree and Sources of Oligopsony Power: An Application to the Haitian Coffee Market

Agribusiness, Industrial Organization,

Predicted HLA Class I and Class II Epitopes From Licensed Vaccines Are Largely Conserved in New SARS-CoV-2 Omicron Variant of Concern

The potential effect of emerging SARS-CoV-2 variants on vaccine efficacy is an issue of critical importance. In this study, the possible impact of mutations that facilitate virus escape from the cytotoxic and the helper cellular immune responses in the new SARS-CoV-2 Omicron variant of concern was analyzed for the 551 and 41 most abundant HLA class I and II alleles, respectively. Computational prediction showed that almost all of these 592 alleles, which cover >90% of the human population, contain enough epitopes without escape mutations in the emerging SARS-CoV-2 Omicron variant of concern. These data suggest that both cytotoxic and helper cellular immune protection elicited by currently licensed vaccines are virtually unaffected by the highly contagious SARS-CoV-2 Omicron variant of concern.This research was supported by grant MPY 388/18 of “Acción Estratégica en Salud” from the ISCIII.S