68 resultados para Undergraduate research


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A free-running, temperature stabilized diode laser has been injection-locked to an external cavity diode laser for use in cold Rydberg atom experiments. Cold rubidium atoms in a magneto-optical trap (MOT) are excited to Rydberg states using a 10 ns laser pulse. The Rydberg atoms spontaneously ionize due to dipole forces, and the collisional ionization dynamics are observed as a function of atom density and principal quantum number of the Rydberg state, n. The injection-locked diode laser will be used as a repumper in conjunction with a dark spontaneous-force optical trap (SPOT) to increase the Rydberg state density. We report on the design of the injection-locked laser system.

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Classical electromagnetism predicts two massless propagating modes, which are known as the two polarizations of the photon. On the other hand, if the Lorentz symmetry of classical electromagnetism is spontaneously broken, the new theory will still have two massless Nambu-Goldstone modes resembling the photon. If the Lorentz symmetry is broken by a bumblebee potential that allows for excitations out of the minimum, then massive modes arise. Furthermore, in curved spacetime, such massive modes will be created through a process other than the usual Higgs mechanism because of the dependence of the bumblebee potential on both the vector field and the metric tensor. Also, it is found that these massive modes do not propagate due to the extra constraints.

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In this study I suggest that there are three distinct time periods mark new developments in society’s understanding of menopause, Victorian America in the mid and late nineteenth century, mid-twentieth century America, and contemporary America. This is the case not only in terms of advances in biological science, but also the ways in which the medical establishment has viewed menopause has also changed, and in terms of changes in prevalent gender assumptions. In this paper I hope to expose the ways science, history, and society has medicalized menopause, and the ways in which menopause has been viewed by individual women, their health care providers, and society as a whole more generally. I also wish to expose the fact that how we have come to think about menopause is by no means simply the result of value-free, objective science and medicine.

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This paper highlights the struggle Nigerian playwright 'Zulu Sofola underwent to impart her message. She attempted to confront gender oppression through tradition without contradicting herself in her play, 'Wedlock of the Gods.' ‘Zulu Sofola wrote commentaries about social problems and the influence of Western culture. Her goal was to maintain a traditional framework in the face of encroaching Western perspectives. She advocated enacting change through tradition, irrespective of Western ideologies about change. Sofola focused on gender oppression as a social problem. She intended to address gender oppression rooted in tradition by teaching traditional customs to her audience in order for audiences to make informed and progressive decisions about what to change within traditional practices. Thus, her traditionalist approach to change requires cognizance and recognition of tradition as an initial step. Sofola argued against the influences of Westernization that shift the focus of change from confronting customs through tradition to confronting customs through Western ideology.

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Aeromonas salmonicida AS03, a potential fish pathogen, was isolated from Atlantic salmon, Salmo salar, in 2003. This strain was found to be resistant to ≥1000 mM HgCl2 and ≥32 mM phenylmercuric acetate as well as multiple antimicrobials. Mercury (Hg) and antibiotic resistance genes are often located on the same mobile genetic elements, so the genetic determinants of both resistances and the possibility of horizontal gene transfer were examined. Specific PCR primers were used to amplify and sequence distinctive regions of the mer operon. A. salmonicida AS03 was found to have a pDU1358-like broad-spectrum mer operon, containing merB as well as merA, merD, merP, merR and merT, most similar to Klebsiella pneumonaie plasmid pRMH760. To our knowledge, the mer operon has never before been documented in Aeromonas spp. PCR and gene sequencing were used to identify class 1 integron associated antibiotic resistance determinants and the Tet A tetracycline resistance gene. The transposase and resolvase genes of Tn1696 were identified through PCR and sequencing with Tn21 specific PCR primers. We provide phenotypic and genotypic evidence that the mer operon, the aforementioned antibiotic resistances, and the Tn1696 transposition module are located on a single plasmid or conjugative transposon that can be transferred to E. coli DH5α through conjugation in the presence of low level Hg and absence of any antibiotic selective pressure. Additionally, the presence of low-level Hg or chloramphenicol in the mating media was found to stimulate conjugation, significantly increasing the transfer frequency of conjugation above the transfer frequency measured with mating media lacking both antibiotics and Hg. This research demonstrates that mercury indirectly selects for the dissemination of the antibiotic resistance genes of A. salmonicida AS03.

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