Classical many-body time crystals

Discrete time crystals are a many-body state of matter where the extensive system's dynamics are slower than the forces acting on it. Nowadays, there is a growing debate regarding the specific properties required to demonstrate such a many-body state, alongside several experimental realizations. In this work, we provide a simple and pedagogical framework by which to obtain many-body time crystals using parametrically coupled resonators. In our analysis, we use classical period-doubling bifurcation theory and present a clear distinction between single-mode time-translation symmetry breaking and a situation where an extensive number of degrees of freedom undergo the transition. We experimentally demonstrate this paradigm using coupled mechanical oscillators, thus providing a clear route for time crystals realizations in real materials.Comment: 23 pages, 5 figures, comments are welcom

The Importance Of Beliefs In Monetary And Financial Settings

This thesis investigates the effects of beliefs in both a monetary and a financial setting. Specifically, the thesis studies the potential effects that price level fluctuations have on societal beliefs, the general medium of exchange, and economic welfare. In a finance setting, this thesis also studies how fluctuations in beliefs can explain the observed hot issues market phenomena in the initial public offering (IPO) equity market. The hot issues market phenomena refers to recurring periods in which the volume of IPOs and the magnitude of their first day returns are observed to be systematically larger than average.;Chapter 2 is a study that exposes the deficiency inherent in monetary models that ignore the medium of exchange function of money. The chapter starts out by reviewing some of the ideas put forward by early economic and social theorists, such as Carl Menger and Georg Simmel, on the origins and continued existence of money as a medium of exchange. Chapter 2 reviews the recently developed search models that formalize the idea that beliefs in an object\u27s ability to act as a medium of exchange are a critical prerequisite for an object to circulate as a medium of exchange. However, in reviewing these search theoretic models of money, the study finds that this approach to modelling money would be an ideal framework in which to formalize the idea that price level fluctuations have a detrimental effect on beliefs and, in the end, on economic welfare.;Chapter 3 of this thesis presents an overview of the defining empirical characteristics of the IPO market as well as a review of some of the explanations put forward regarding the empirical anomalies associated with the pricing and the volume of IPOs. In reviewing the literature concerned with the IPO process, this chapter also shows that the hot issues market phenomena needs further study.;Chapter 4 empirically investigates various implications of the windows of opportunity explanation of the hot issues market phenomena. This informal explanation relies on a form of investor speculation. Specifically, it assumes that investors undergo periods (or regimes) in which they hold overoptimistic beliefs about the expected returns of firms in certain sectors or industries. Subsequently, the stocks in these sectors become overvalued. Companies take advantage of the overvaluation of stocks in their related sector and decide to go public during these periods of investor overenthusiasm. Thus, this explanation suggests that the observed cyclical fluctuations in IPO data may be better viewed as fluctuations arising from unobservable stochastic regime changes in investor sentiment.;In order to be able to test for the presence of recurring stochastic regime changes in the IPO data, a Markov switching technique for modelling time series processes subject to discrete state-dependent regime changes is used.;In the fifth chapter the firm\u27s decision to go public is modelled using an optimal stopping model found in statistical decision theory. This model formalizes the windows of opportunity hypothesis of the hot issues market phenomena. This model predicts that IPOs will be clustered during certain periods. By allowing some degree of firm heterogeneity, as measured by the firms\u27 public information content, this model also predicts that older, larger information rich firms are more likely to go public than information poor firms. (Abstract shortened by UMI.

«My Proof of Life»: el VIH como reificación de la metafísica negra en Homie de Danez Smith

Des de la seva aparició als anys huitanta, la literatura ha respost a la pandèmia de VIH/SIDA amb treballs que testimonien la devastadora pèrdua patida per milions de persones arreu del món. Després de la implementació de tractaments antiretrovirals efectius (TAR) a mitjans dels anys noranta, tanmateix, podria esperar-se que les experiències contemporànies de VIH canviaren la seva atenció des de l’afecció i el dol a emocions més “positives”. L’objectiu d’aquest article és considerar el potencial canvi de paradigma entre les noves generacions de gent seropositiva amb accés a TAR. A tal efecte, l’article explora l’aproximació lírica que Danez Smith fa a l’experiència racialitzada de VIH al segle XXI, intentant llegir aquesta experiència com constructiva en lloc de destructiva, sense deixar de banda la interseccionalitat, i en el context de l’afropessimisme i de l’optimisme queer.Since its onset in the 1980s, literature has responded to the HIV/AIDS pandemic with works that testify to the devastating loss imposed on millions of people worldwide. After the implementation of effective antiretroviral treatment (ART) in the mid-90s, however, contemporary experiences of HIV might be expected to diverge their attention from grief and mourning to more “positive” emotions. The aim of this paper is to consider such a potential paradigm shift among new generations of HIV+ people with access to ART. To do so, it explores Danez Smith’s lyric approach to a 21st-century racialized experience of HIV, attempting to read it as constructive rather than destructive, without leaving intersectionality aside, in light of both Afropessimism and Queer Optimism.Desde la aparición del VIH/SIDA en la década de 1980, la literatura ha respondido a la pandemia con trabajos que dan testimonio de la devastadora pérdida impuesta a millones de personas en todo el mundo. Sin embargo, después de la implementación de un tratamiento antirretroviral eficaz (TAR) a mediados de los años noventa, es de esperar que las experiencias contemporáneas del VIH desviaran su atención del dolor y el duelo hacia emociones más «positivas». El objetivo de este artículo es considerar este potencial cambio de paradigma entre las nuevas generaciones de personas VIH+ con acceso al TAR. Para ello explora el enfoque lírico que lleva a cabo Danez Smith de la experiencia racializada del VIH del siglo XXI, e intenta leer esta experiencia como constructiva en lugar de destructiva, sin dejar de lado la interseccionalidad y considerando en este contexto las perspectivas del afropesimismo y del optimismo queer

«My Proof Of Life»: HIV as Reification of Black Metaphysics in Danez Smith's Homie

[eng] Since the onset of HIV/AIDS in the 1980s, literature has responded to the pandemic with works that testify to the devastating loss imposed on millions of people worldwide. After the implementation of effective antiretroviral treatment (ART) in the mid-90s, however, contemporary experiences of HIV might be expected to diverge their attention from grief and mourning to more 'positive' emotions. The aim of this paper is to consider such a potential paradigm shift among new generations of HIV+ people with access to ART. To do so, it explores Danez Smith's lyric approach to a 21st-century racialized experience of HIV, attempting to read it as constructive rather than destructive, without leaving intersectionality aside, in light of both Afropessimism and Queer Optimism

The Effects of Constant Time Delay in Teaching Recognition of Braille Words

The purpose of the study was to evaluate the use of a constant time delay procedure to teach core content words in braille to a student with a visual impairment. A multiple probe (conditions) across behaviors design was used to evaluate the effectiveness of the training and follow-up sessions. The results showed the procedure was effective in teaching core content braille words within a resource setting and the student was able to generalize the information to an inclusive setting

Internal Finance and Firm Investment

We examine the neoclassical investment model using a panel of U.S. manufacturing firms. The standard model with no financing constraints cannot be rejected for firms with high (pre-sample) dividend payouts. However, it is decisively rejected for firms with low (pre-sample) payouts (firms we expect to face financing constraints). Hem, investment is sensitive to both firm cash flow and macroeconomic credit conditions, holding constant investment opportunities. Sample splits based on firm size or maturity do not produce such distinctions. The latter comparison identifies firms where "free-cash-flow" problems might be expected to produce correlations between investment and cash flow.

Analysis of potential archaeal NER endonuclease homologs using Saccharomyces cervisiae

The nuclease proteins involved in eukaryotic nucleotide excision repair (NER) have been identified and are ubiquitous for most eukaryotes, including XPF (3’ endonuclease) and XPG (5’ endonuclease). Proteins with similar structures have been identified in archaeal genomes and have been shown to exhibit endonuclease activity, but their overall cellular functions have not been elucidated. The proteins Hef1 and Bax1 in archaea are two of such proteins that are candidates for homology with the XPF (Rad1 in Saccharomyces cerevisiae) nuclease. By inserting plasmids containing archaeal genes coding for these possible homologous nucleases into Saccharomyces cerevisiae without Rad1 gene (ΔRad1) and then exposing the cells to Ultraviolet (UV) light, NER function can be analyzed using survival rates. These experiments aim to investigate the function of these potential homologous XPF nucleases present in archaea

Fast plants and gene x environment interactions for the Biology 202 laboratory

Phenotypic plasticity is the ability for a single genotype to produce multiple phenotypes in response to environmental variation. The phenotypic plasticity of a genotype is described by its norm of reaction, and norms of reaction for different genotypes might suggest that each is favored by a different environment. In this experiment, we established a fertility gradient and produced norms of reaction for a variety of measures of plant performance using two strains of Wisconsin Fast Plants (“Astro” and “Dwarf”). The Dwarf variety performed best at low fertility levels, while the Astro variety performed best at high fertility levels. Using these results, we predicted that if Dwarf and Astro varieties were allowed to compete, their relative success would correspond to the differences in their norms of reaction. This prediction seemed to be supported when competition involved one plant of each variety, but when two plants of each variety competed, Astro generally performed best across the fertility gradient. With further improvement, this system can provide an opportunity for students to generate and test predictions regarding phenotypic plasticity in introductory biology laboratories

"I Got the Cell Count Blues:" Danez Smith, HIV, and the Legacy of the Black Arts Movement

This paper connects Danez Smith’s collection of poems Don’t Call Us Dead (2017) to writing by the poet’s predecessors in the Black Arts Movement. I argue that Smith’s expression of HIV in their poetry continues and updates the denunciation of mass incarceration of, as well as structural violence against, non-white US citizens. My goal is to analyze intertextuality and the main topoi in Smith’s poetry as elements contributing to the extension of the BAM’s attempt to raise awareness and create Black self-determination and nationhood (Neal 1969). To do so, I read Smith’s work in light of contemporary thought, focusing on Judith Butler’s (2004) ideas of grievability, indefinite detention, and the hierarchies of death