Superluminous supernovae: No threat from Eta Carinae

Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree.Comment: 19 pages, 2 figures; Revised version as accepted for publication in Astrobiolog

The implementation of comparable worth : challenges to sex-based wage discrimination

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 1985.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ROTCHBibliography: leaves 103-109.by Barbara Gwen Fields.M.C.P

Validity of new child-specific thoracic gas volume prediction equations for air-displacement plethysmography

BACKGROUND: To determine the validity of the recently developed child-specific thoracic gas volume (TGV) prediction equations for use in air-displacement plethysmography (ADP) in diverse pediatric populations. METHODS: Three distinct populations were studied: European American and African American children living in Birmingham, Alabama and European children living in Lisbon, Portugal. Each child completed a standard ADP testing protocol, including a measured TGV according to the manufactures software criteria. Measured TGV was compared to the predicted TGV from current adult-based ADP proprietary equations and to the recently developed child-specific TGV equations of Fields et al. Similarly, percent body fat, derived using the TGV prediction equations, was compared to percent body fat derived using measured TGV. RESULTS: Predicted TGV from adult-based equations was significantly different from measured TGV in girls from each of the three ethnic groups (P < 0.05), however child-specific TGV estimates did not significantly differ from measured TGV in any of the ethnic or gender groups. Percent body fat estimates using adult-derived and child-specific TGV estimates did not differ significantly from percent body fat measures using measured TGV in any of the groups. CONCLUSION: The child-specific TGV equations developed by Fields et al. provided a modest improvement over the adult-based TGV equations in an ethnically diverse group of children

Measurements and analyses of transposable element activity inside living cells

Transposable elements (TEs) are DNA elements that move into different places in the DNA. Through their activity, they can restructure genomes and play crucial roles in evolution, development, and genetic disease. However, characterization of their detailed in vivo dynamics has been limited by a lack of direct observational methods. Here, we present novel methods that quantify biophysical characteristics of TEs in unprecedented detail. For the first study, we modify the bacterial transposable element IS608 to quantify its activity in single cells via fluorescence microscopy. The system can reveal single events, cell-to-cell variations, and temporal and environmental variabilities in real time and individual living cells. With this system, we characterize the relationship of the level of transposase protein with TE activity for different orientations of the TE in the genome. We also perform real-time activity detection and find that the activity is highly variable depending on the growth phase, local environment, and growth history of host cells. Secondly, we copy from the human genome a long interspersed nuclear element, LINE-1, one of the most prevalent and active transposable elements in humans. We introduce LINE-1 into the bacteria Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) and demonstrate that it is active in the bacteria and successfully integrates into the bacterial host genomes. The LINE-1 activity decreases the bulk growth rate of bacteria exponentially in response to its increasing expression. Our work suggests that E. coli can be a simple and useful model system to investigate the biophysical properties of LINE-1 element dynamics and their effects on host cells. In the last chapter, we present the technical development of a novel method for versatile and precise genome editing of E. coli, based on the Landing Pad intermediate method suited for the integration of large size DNA fragments at arbitrary locations in E. coli chromosome. Various genome modifications were made to show the power of this method, which include antibiotic-free selection methods, exact integration of long sequences (~6.5kbp) to any given target location, scar-less deletions, and gene fusion to native genes in situ

The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe

The preponderance of matter over antimatter in the early Universe, the dynamics of the supernova bursts that produced the heavy elements necessary for life and whether protons eventually decay --- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our Universe, its current state and its eventual fate. The Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed plan for a world-class experiment dedicated to addressing these questions. LBNE is conceived around three central components: (1) a new, high-intensity neutrino source generated from a megawatt-class proton accelerator at Fermi National Accelerator Laboratory, (2) a near neutrino detector just downstream of the source, and (3) a massive liquid argon time-projection chamber deployed as a far detector deep underground at the Sanford Underground Research Facility. This facility, located at the site of the former Homestake Mine in Lead, South Dakota, is approximately 1,300 km from the neutrino source at Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino charge-parity symmetry violation and mass ordering effects. This ambitious yet cost-effective design incorporates scalability and flexibility and can accommodate a variety of upgrades and contributions. With its exceptional combination of experimental configuration, technical capabilities, and potential for transformative discoveries, LBNE promises to be a vital facility for the field of particle physics worldwide, providing physicists from around the globe with opportunities to collaborate in a twenty to thirty year program of exciting science. In this document we provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess.Comment: Major update of previous version. This is the reference document for LBNE science program and current status. Chapters 1, 3, and 9 provide a comprehensive overview of LBNE's scientific objectives, its place in the landscape of neutrino physics worldwide, the technologies it will incorporate and the capabilities it will possess. 288 pages, 116 figure

The Qur'an and Identity in Contemporary Chinese Fiction

How is it possible to comprehend and assess the impact of the Qur’an on the literary expressions of Chinese Muslims (Hui) when the first full ‘translations’ of the Qur’an in Chinese made by non-Muslims from Japanese and English appeared only in 1927 and 1931, and by a Muslim from Arabic in 1932? But perhaps the fact that such a translation appeared so late in the history of the Muslim community in China, who have had a continuous presence since the ninth-century, is the best starting point. For it would be possible to address the relationship between the sacred text (as well as language) and identity among minority groups in a different way. This paper looks at the ways in which the Qur’an is imagined then embodied in literary texts authored by two prize-winning Chinese Muslim authors: Huo Da (b. 1945) and Zhang Chengzhi (b. 1948). While Huo Da, who does not have access to the Arabic language, alludes to the Chinese Qur’an in her novel, The Muslim’s Funeral (1982), transforming the its teachings into ritual performances of alterity through injecting Arabic and Persian words for religious rituals into her narrative of a Muslim family’s fortunes at the turn of the twentieth century, Zhang Chengzhi, who learned Arabic as an adult and travelled widely in the Muslim world, involves himself in reconstructing the history of the spread and persecution of the Jahriyya Sufi sect (an off-shoot of the Naqshabandiyya) in China between the seventeenth and nineteenth centuries in his only historical novel, A History of the Soul (1991), and in education reform in Muslim communities, inventing an identity for Chinese Muslims based on direct knowledge of the sacred text and tradition and informed by the history of Islam not in China alone but in the global Islamic world, especially Arabic Islamic history

Lack of Effective Anti-Apoptotic Activities Restricts Growth of Parachlamydiaceae in Insect Cells

The fundamental role of programmed cell death in host defense is highlighted by the multitude of anti-apoptotic strategies evolved by various microbes, including the well-known obligate intracellular bacterial pathogens Chlamydia trachomatis and Chlamydia (Chlamydophila) pneumoniae. As inhibition of apoptosis is assumed to be essential for a successful infection of humans by these chlamydiae, we analyzed the anti-apoptotic capacity of close relatives that occur as symbionts of amoebae and might represent emerging pathogens. While Simkania negevensis was able to efficiently replicate within insect cells, which served as model for metazoan-derived host cells, the Parachlamydiaceae (Parachlamydia acanthamoebae and Protochlamydia amoebophila) displayed limited intracellular growth, yet these bacteria induced typical features of apoptotic cell death, including formation of apoptotic bodies, nuclear condensation, internucleosomal DNA fragmentation, and effector caspase activity. Induction of apoptosis was dependent on bacterial activity, but not bacterial de novo protein synthesis, and was detectable already at very early stages of infection. Experimental inhibition of host cell death greatly enhanced parachlamydial replication, suggesting that lack of potent anti-apoptotic activities in Parachlamydiaceae may represent an important factor compromising their ability to successfully infect non-protozoan hosts. These findings highlight the importance of the evolution of anti-apoptotic traits for the success of chlamydiae as pathogens of humans and animals