Past Periphery

Past Periphery examines a contemporary manifestation of the mammy archetype. The common threads between the works presented in the thesis exhibition are erasure, invisibility, and projection. The flattening of a person into icon is the equivalent of the One standing in for the Many. The One embodies surface qualities only and ultimately provides and inadequate summary of the individual or the group. This misrepresentation is the face offered up for public consumption and becomes the foundation for commodity as well as identity. We label, package, sell, and consume this icon as true and correct. But it becomes impossible to define the cultural or ethnic breadth of our so-called inclusive cultural consciousness. The three-dimensional becomes two-dimensional. Iconic representations of racial identity, like mammy, supplant the need for inclusive perspectives that embrace difference. Nationalistic systems that tout Identity as shared experiences effectively deny the role of the individual as shaper of collective awareness. The disembodied individual is left with a fragmented history. Past Periphery examines the fragments, allowing them to function as a lens

The Evolution of Gamma-ray Burst Jet Opening Angle through Cosmic Time

Jet opening angles of long gamma-ray bursts (lGRBs) appear to evolve in cosmic time, with lGRBs at higher redshifts being on average more narrowly beamed than those at lower redshifts. We examine the nature of this anti-correlation in the context of collimation by the progenitor stellar envelope. First, we show that the data indicate a strong correlation between gamma-ray luminosity and jet opening angle, and suggest this is a natural selection effect - only the most luminous GRBs are able to successfully launch jets with large opening angles. Then, by considering progenitor properties expected to evolve through cosmic time, we show that denser stars lead to more collimated jets; we argue that the apparent anti-correlation between opening angle and redshift can be accounted for if lGRB massive star progenitors at high redshifts have higher average density compared to those at lower redshifts. This may be viable for an evolving IMF - under the assumption that average density scales directly with mass, this relationship is consistent with the form of the IMF mass evolution suggested in the literature. The jet angle-redshift anti-correlation may also be explained if the lGRB progenitor population is dominated by massive stars at high redshift, while lower redshift lGRBs allow for a greater diversity of progenitor systems (that may fail to collimate the jet as acutely). Overall, however, we find both the jet angle-redshift anti-correlation and jet angle-luminosity correlation are consistent with the conditions of jet launch through, and collimation by, the envelope of a massive star progenitor

Co-reminiscing with a caregiver about a devastating tornado: Association with adolescent anxiety symptoms

This study explores the association between caregivers’ style of co-reminiscing with their adolescents about an EF4 tornado and youth anxiety symptoms several years following the disaster. Caregiver reward of their children’s emotional expression, defined as attending to and validating emotionally salient content, is generally associated with adaptive youth psychosocial outcomes. However, caregiver reward of youth recollections that are centered around the youth’s negative emotional expression could be an indicator that both caregivers and adolescents are engaged in co-rumination regarding negative emotional experiences. This process may contribute to relatively higher levels of anxiety over time. Adolescents (N = 169) drawn from an ongoing study for aggressive youth (ages 12 to 17; 82% African American) provided individual recollections about their experiences during a devastating tornado 4 to 5 years following the disaster. Caregivers and youth then co-reminisced about their tornado-related experiences. Individual youth recollections were coded for negative personal impact and use of negative emotion words; caregiver–adolescent conversations were coded for caregiver reward of negative emotional expression. Youth who noted more negative personal impacts and used more negative emotion words were higher in parent-rated youth anxiety, and these associations were moderated by caregiver reward of negative emotional expression. The associations between youth recollection qualities and anxiety emerged only when caregivers exhibited high levels of reward of negative emotional expression. These patterns were generally stronger for girls compared to boys. Findings suggest that excessively discussing and rehashing negative experiences, especially several years after the disaster, may be a risk factor for anxiety among disaster-exposed adolescents

On the Anti-Correlation between Duration and Redshift in Gamma-ray Bursts

For gamma-ray bursts (GRBs) with durations greater than two seconds (so-called long GRBs), the intrinsic prompt gamma-ray emission appears, on average, to last longer for bursts at lower redshifts. We explore the nature of this duration-redshift anti-correlation, describing systems and conditions in which this cosmological evolution could arise. In particular, we explore its dependence on metallicity of a massive star progenitor, as we can securely count on the average stellar metallicity to increase with decreasing redshift. Although higher metallicity/lower redshift stars lose mass and angular momentum through line-driven winds, in some cases these stars are able to form more extended accretion disks when they collapse, potentially leading to longer duration GRBs. We also examine how this duration-redshift trend may show up in interacting binary models composed of a massive star and compact object companion, recently suggested to be the progenitors of radio bright GRBs. Under certain conditions, mass loss and equation of state effects from higher metallicity, lower redshift massive stars can decrease the binary separation. This can then lead to spin-up of the massive star and allow for a longer duration GRB upon the massive star's collapse. Finally, the duration-redshift trend may also be supported by a relatively larger population of small-separation binaries born in situ at low redshift.Comment: Accepted to Ap