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Decolonization is Women\u27s Work
No full textMarch 8, 1950—International Women’s Day—Marked the Embrace of a Feminist Battle Against Imperialis
Regularity Theory of Quasilinear Ellipitic and Parabolic Equations in the Heisenberg Group
Get PDFThis note provides a succinct survey of the existing literature concerning the H¨older regularity for the gradient of weak solutions of PDEs of the form modeled on the p-Laplacian in a domain Ω in the Heisenberg group Hn, with 1 ≤ p \u3c ∞, and of its parabolic counterpart. We present some open problems and outline some of the difficulties they present
In vitro Toxicity and Mutagenicity Evaluation of Sesquiterpene Lactones Derived from Neurolaena lobata as Potential Drug Candidates for Lymphatic Filariasis
No full textLymphatic filariasis (LF) is a neglected tropical disease, or NTD, that currently burdens over 50 million people worldwide and is caused by three species of nematodes. Currently, mass drug administration (MDA) is the primary method for distributing treatments to endemic countries. However, the drugs distributed on this mass scale don’t target adult nematodes, which occupy the lymphatic system in mammals and cause most of the symptomatic effects of LF. Adult nematodes also produce microfilariae that can be transmitted from host to mosquito vector.. Because of this, there is a need for a new compound that can target both the larval stages of the nematodes as well as the adults. We are investigating how effective semisynthetic derivatives of sesquiterpene lactones from the Neurolaena lobata plant are in terms of killing adult worms and microfilariae. The most effective derivative was found to be neurolenin D mesylate (NDM), in comparison with the natural product neurolenin B (NB). In order to take all of the necessary steps involved with developing a potential drug candidate in order to receive a patent (which is required for a drug to be considered for MDA), we then assessed the mutagenicity and cytotoxicity of NDM in comparison to NB. The Ames test is the gold standard biological assay used to determine the mutagenicity of a given compound. Using this assay, we determined that neurolenin has no mutagenic effects. To assess potential cytotoxic effects of neurolenin derivatives, we used the Cell Counting Kit-8 (CCK-8) test. This assay utilizes cultured HEK 293 cells and a water-soluble tetrazolium salt in order to demonstrate electron transfer in living cells. We determined that neurolenin has no cellular toxicity. Because of the demonstrated activity of neurolenin derivatives against Brugia pahangi and their low levels of mutagenicity and toxicity, we have identified a novel potential drug candidate for the treatment 7 of lymphatic filariasis and potentially other neglected tropical diseases caused by filarial parasites
Bacterial Microbiome Variation Across Symbiotic State and Clonal Lines in a Cnidarian Model
No full textCoral reef ecosystems support approximately a quarter of all marine life and provide numerous ecosystem services. Intensifying climate change has threatened coral reefs worldwide. In order to address this crisis, we must first understand the dynamics surrounding coral health and fitness. Exaiptasia diaphana is a popular model organism for exploring the symbiotic relationship observed between cnidarians and their microsymbionts. While physiological roles of algal photosymbionts (Symbiodinaceae) are well studied, the contributions of bacterial communities are less defined in this system. I investigated microbial variation between distinct parts of the body and symbiotic state across four genets held in identical environmental conditions using 16s rRNA gene amplicon sequencing. I found differentially abundant taxa between body part and symbiotic state that highlight the roles these bacteria may play in holobiont heterotrophy and nutrient cycling. Beta-diversity analysis revealed distinct communities between symbiotic states consistent with previous studies; however, I did not observe the presence of previously reported core microbiota. I also found community differences across clonal lines, both compositionally and functionally, despite years of identical rearing conditions. These findings suggest the Exaiptasia bacterial microbiome is greatly influenced by host geneti cs and unpredictable environmental influences
Precision Spectroscopy of Atomic Nitrogen-14 and Oxygen-16
No full textQuantum field theory (QFT) is a mathematical model that combines classical field theory, quantum mechanics, and special relativity. Quantum electrodynamics (QED), a type of quantum field theory, is one of the most rigorously tested fundamental theories of nature. QED describes how light and matter interact, and it is the first theory that completely combines quantum mechanics and special relativity. Despite its many successes, QFT is not a complete theory. This motivates the work behind this thesis. This thesis describes spectroscopic measurements that, when combined with future theoretical calculations and more experimental results, will serve as a test of the validity of QED for multielectron systems. In particular, high precision spectroscopic measurements on the 2p3(4S◦)3p(5P)1,2,3 − 2p3(4S◦)3d(5D◦)0,1,2,3,4 transitions in atomic oxygen-16 are presented. For the oxygen transitions, the transition frequencies have been experimentally measured to be: Transition Frequency (MHz) 2p3(4S◦)3p 5P1 → 2p3(4S◦)3d 5D◦ 0 323 633 229.7(18) 2p3(4S◦)3p 5P1 → 2p3(4S◦)3d 5D◦ 1 323 631 445.1(12) 2p3(4S◦)3p 5P1 → 2p3(4S◦)3d 5D◦ 2 323 628 321.35(33) 2p3(4S◦)3p 5P2 → 2p3(4S◦)3d 5D◦ 1 323 570 859.32(42) 2p3(4S◦)3p 5P2 → 2p3(4S◦)3d 5D◦ 2 323 567 734.39(39) 2p3(4S◦)3p 5P2 → 2p3(4S◦)3d 5D◦ 3 323 564 162.37(37) 2p3(4S◦)3p 5P3 → 2p3(4S◦)3d 5D◦ 2 323 457 614.91(97) 2p3(4S◦)3p 5P3 → 2p3(4S◦)3d 5D◦ 3 323 454 042.29(43) 2p3(4S◦)3p 5P3 → 2p3(4S◦)3d 5D◦ 4 323 451 393.36(33) The above numbers represent an improvement of up to a factor 2000 over previous measurements. In addition, an unidentified transition with three features observed with frequency near the 2s22p2(3P)3s 2P3/2 → 2s22p2(3P)3p 2D◦ 5/2 transition in atomic nitrogen-14 was fully studied; this line is still not identified. Finally, spectrum for the 4f76s2 8S◦ 7/2 → 4f7(8S◦)6s6p(1P◦) 8P5/2,7/2,9/2 transitions in neutral europium-151 and europium-153 were taken. These measurements were completed to assist current experimental studies of ultracold europium atoms and do not serve as a test of QED. For the transition to the J=9/2 excited state, the transition frequency was found to be 652,389,757.16(34) MHz and 652,386,593.2(5) MHz, respectively. The hyperfine coefficients were found to be A(151)=-228.84(2)MHz, B(151)=226.9(5)MHz and A(153)=-101.87(6)MHz, B(153)=575.4(1.5)MHz, which all agree with previously published results except for A(153), which shows a small discrepancy. The isotope shift is found to be 3163.8(6) MHz, which also has a discrepancy with previously published results. Analysis of the other two transitions is ongoing
Agency and Strategy: Chastity Exemplars in an Early Qing Anthology
Get PDFThis article reads exemplary biographies of chaste widows and women who committed suicide to preserve their chastity in the 1656 Yuding Nei ze yanyi 御定内則衍義 (Imperially Commissioned Expanded Meaning of the “Inner Standards”) by Fu Yijian 傅以漸 (1609–1665, jinshi 1646). In this anthology commissioned by the Shunzhi emperor on behalf of his mother, Fu\u27s commentary emphasizes both the agency of individual women and the mutual resonance of personal virtue and political order. He not only praises the exemplars\u27 virtue but also their agency, intelligence, and strategy. He explicitly acknowledges the different factors that could make chastity more difficult and states that in some situations, multiple courses of action were possible. He comments both on his heroines\u27 political ability and on the political importance of recognizing chastity. Finally, in a context where women\u27s chastity was often linked to political loyalism to the fallen Ming, Fu uses these biographies in a very different way: he presents chastity exemplars of conquered dynasties as foils to the decadent society around them. His commentary is thus recognizably tailored to his audience\u27s circumstances as Manchu and Mongolian imperial women and his own as a Chinese male scholar at the beginning of the Qing
Absolute Frequency Measurement of the \u3ci\u3e2p\u3csup\u3e2\u3c/sup\u3e(\u3csup\u3e3\u3c/sup\u3ep)3s \u3csup\u3e2\u3c/sup\u3eP–2p\u3csup\u3e2\u3c/sup\u3e(\u3csup\u3e3\u3c/sup\u3ep)3p \u3csup\u3e2\u3c/sup\u3eD\u3csup\u3eo\u3c/sup\u3e \u3c/i\u3eTransitions in Neutral \u3ci\u3e\u3csup\u3e14\u3c/sup\u3eN\u3c/i\u3e
Get PDFWe report absolute frequency measurements on the three excited-state transitions connecting the 2��2(3��)3��2��1/2,3/2 and 2��2(3��)3��2��∘3/2,5/2 states in neutral 14N using saturated absorption spectroscopy in a glass cell filled with a mixture of nitrogen and argon gas and driven with a radio-frequency electric field. The absolute transition frequencies are found to be 319 288 834(150), 319 085 445(125), and 316 795 808(140) MHz for the 1/2–3/2, 3/2–5/2, and 3/2–3/2 transitions, respectively. This work represents the saturated absorption measurements for these transitions. These results are approximately a factor of 5 improvement over previous results, despite being conservative estimates. We found that the overlapping hyperfine structure prevented fitting individual spectral features, presenting difficulties for possible future tests of quantum electrodynamics in seven-electron systems. A better understanding of the amplitude behavior of a merged hyperfine structure will allow the extrapolation of the center of gravity frequencies for these transitions to sub-MHz precision using our collected data
Aggregate Effects of Proliferating Low-Earth-Orbit Objects and Implications for Astronomical Data Lost in the Noise
Get PDFThe rising population of artificial satellites and associated debris in low-altitude orbits is increasing the overall brightness of the night sky, threatening ground-based astronomy as well as a diversity of stakeholders and ecosystems reliant on dark skies. We present calculations of the potentially large rise in global sky brightness from space objects in low Earth orbit, including qualitative and quantitative assessments of how professional astronomy may be affected. Debris proliferation is of special concern: we calculate that all log-decades in debris size contribute approximately the same amount of night sky radiance, so debris-generating events are expected to lead to a rapid rise in night sky brightness along with serious collision risks for satellites from centimetre-sized objects. This increase in low-Earth-orbit traffic will lead to loss of astronomical data and diminish opportunities for ground-based discoveries as faint astrophysical signals become increasingly lost in the noise. Lastly, we discuss the broader consequences of brighter skies for a range of sky constituencies, equity/inclusion and accessibility for Earth- and space-based science, and cultural sky traditions. Space and dark skies represent an intangible heritage that deserves intentional preservation and safeguarding for future generations