380 research outputs found

    The Lewis and Clark Journey: Burning Bridges and Building Empires

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    The purpose of this paper is to analyze the expedition of Lewis and Clark from 1804 to 1806 as they crossed the territory of Louisiana. Their journey has become one of the most important symbols of American history and its memory has been far reaching. More specifically, this paper aims to examine more closely the interactions that Meriwether Lewis and William Clark had with the Native Americans. Thomas Jefferson had an extensive list of requests and instructions for the two explorers. While this paper will not analyze all of Jefferson’s requests, there are two that will be featured in this paper for such analysis. The first topic that will be discussed is the attempt by Lewis and Clark and the rest of the Corps of Discovery to create a lasting environment of peace and harmony between the Native Americans of the previously unexplored western frontier and the government and citizens of the United States of America. The second topic that will be discussed in this paper is the attempt of the explorers to build a commercial relationship with these same groups

    1940 Ruby Yearbook

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    A digitized copy of the 1940 Ruby, the Ursinus College yearbook.https://digitalcommons.ursinus.edu/ruby/1042/thumbnail.jp

    Combining Experiment and Theory to Elucidate the Role of Supercritical Water in Sulfide Decomposition

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    The cleavage of C–S linkages plays a key role in fuel processing and organic geochemistry. Water is known to affect these processes, and several hypotheses have been proposed, but the mechanism has been elusive. Here we use both experiment and theory to demonstrate that supercritical water reacts with intermediates formed during alkyl sulfide decomposition. During hexyl sulfide decomposition in supercritical water, pentane and CO + CO2 were detected in addition to the expected six carbon products. A multi-step reaction sequence for hexyl sulfide reacting with supercritical water is proposed which explains the surprising products, and quantum chemical calculations provide quantitative rates that support the proposed mechanism. The key sequence is cleavage of one C–S bond to form a thioaldehyde via radical reactions, followed by a pericyclic addition of water to the CS bond to form a geminal mercaptoalcohol. The mercaptoalcohol decomposes into an aldehyde and H2S either directly or via a water-catalyzed 6-membered ring transition state. The aldehyde quickly decomposes into CO plus pentane by radical reactions. The time is ripe for quantitative modelling of organosulfur reaction kinetics based on modern quantum chemistry

    OPTIMISING ACOUSTIC RESONATORS FOR SONOFUSION EXPERIMENTS WITH EVOLUTIONARY ALGORITHMS

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    The sizing of simple resonators like guitar strings or laser mirrors is directly connected to the wavelength and represents no complex optimisation problem. This is not the case with liquid-filled acoustic resonators of non-trivial geometries, where several masses and stiffnesses of the structure and the fluid have to fit together. This creates a scenario of many competing and interacting resonances varying in relative strength and frequency when design parameters change. Hence, the resonator design involves a parameter-tuning problem with many local optima. As its solution evolutionary algorithms (EA) coupled to a forced-harmonic FE simulation are presented. A new hybrid EA is proposed and compared to two state-of-theart EAs based on selected test problems. The motivating background is the search for better resonators suitable for sonofusion experiments where extreme states of matter are sought in collapsing cavitation bubbles

    Activation of gene expression by detergent-like protein domains

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    The mechanisms by which transcriptional activation domains (tADs) initiate eukaryotic gene expression have been an enigma for decades because most tADs lack specificity in sequence, structure, and interactions with targets. Machine learning analysis of data sets of tAD sequences generated in vivo elucidated several functionality rules: the functional tAD sequences should (i) be devoid of or depleted with basic amino acid residues, (ii) be enriched with aromatic and acidic residues, (iii) be with aromatic residues localized mostly near the terminus of the sequence, and acidic residues localized more internally within a span of 20–30 amino acids, (iv) be with both aromatic and acidic residues preferably spread out in the sequence and not clustered, and (v) not be separated by occasional basic residues. These and other more subtle rules are not absolute, reflecting absence of a tAD consensus sequence, enormous variability, and consistent with surfactant-like tAD biochemical properties. The findings are compatible with the paradigm-shifting nucleosome detergent mechanism of gene expression activation, contributing to the development of the liquid-liquid phase separation model and the biochemistry of near-stochastic functional allosteric interactions

    1941 Ruby Yearbook

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    A digitized copy of the 1941 Ruby, the Ursinus College yearbook.https://digitalcommons.ursinus.edu/ruby/1043/thumbnail.jp

    The Grizzly, October 29, 1997

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    Pennsylvania German Art Featured at Berman Art Museum • Pfahler Workers Dismissed • New Chaplain Introduced to Community • Commonwealth Brawl Raises Student Concern • Opinion: Award Winning My Ass; A Sweet Suite; Kudos to the College; Hail to the Queen; Leaving Home for Homecoming • Ghost Stories • Bears to Clash with Muhlenberg Mules • Men\u27s B-ball Gearing Up • Player Profiles: Lieberman, Steigerwalt Lead by Example; Mahoney a Constant Force for Young Women\u27s Teamhttps://digitalcommons.ursinus.edu/grizzlynews/1408/thumbnail.jp

    Compositional characteristics and spatial distribution of enriched Icelandic mantle components

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    Author Posting. © The Authors, 2010. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Journal of Petrology 51 (2010): 1447-1475, doi:10.1093/petrology/egq025.We present compositional data on a suite of 18 primitive neovolcanic alkali basalts from three flank zone regions in Iceland (Vestmannaeyjar in the south, Snæfell in the east, and Snæfellsnes in the west) that are peripheral to the main rift zones that are dominated by tholeiitic basalts. This study integrates He isotope data with radiogenic isotope data (Sr-Nd-Pb-Hf), stable isotope data (δ18O), and trace element data to characterise the compositional features of the trace-elementenriched components of the Icelandic mantle. We also present high-precision Pb isotope data on an additional 57 lava samples from the flank zones (including Öræfajökull in the south-east) and the Northern and Eastern rift zones. Most Icelandic lavas have negative Δ207Pb (–4 to –1), with higher values (–1 to +4) found only in samples from Öræfajökull, Snæfell, and parts of the Reykjanes Peninsula. At Snæfell, this EM1-type component is characterised by a low δ18Oolivine signature (+4.1‰ to +4.6‰), moderate 206Pb/204Pb values (18.4-18.6) and MORB-like 3He/4He (6.9-7.5 R/RA). Samples from Vestmannaeyjar and Snæfellsnes have mantle-like δ18Oolivine (+4.9‰ to +5.0‰), and radiogenic 206Pb/204Pb values (18.9-19.3) that fall on the NHRL for 208Pb/204Pb (Δ208Pb –5 to +5). Compared to the Vestmannaeyjar lavas, Snæfellsnes lavas have higher La/YbN (5-11 vs. 3-5), lower εNd (5.5-6.5 vs. 6.8-7.6) and lower 3He/4He (6.3-8.6 R/RA vs. 11.4-13.5 R/RA). Therefore, the most trace element enriched components in the Icelandic mantle are not the carriers of the high 3He/4He values (> 15 R/RA) found in some lavas on Iceland and the adjacent ridges, and instead are consistent with degassed, recycled components. Even after excluding the EM1-type high Δ207Pb samples, high-precision Pb isotope data produce a kinked array on an 206Pb/204Pb vs. 208Pb/204Pb plot, which is not consistent with simple binary mixing between two end-members. This requires significant lateral heterogeneity within the Icelandic mantle and the presence of more than just two compositionally-distinct local mixing end-member components. Samples from each of the main axial rift zones define different trends. Despite the tectonic continuity between the Northern Volcanic Zone and the Eastern Volcanic Zone, lavas from these two rift zones define separate sub-parallel linear arrays. Lavas from the adjacent Western Volcanic Zone and the Eastern Volcanic Zone define oblique linear arrays that converge on a common local end-member that is not involved in the magmatism of the Northern Volcanic Zone. Therefore, there is a distinct NE-SW compositional heterogeneity within the Icelandic mantle.work was funded primarily by the Danish National Research Foundation through a grant to the former Danish Lithosphere Centre, with additional funding from the University of Iowa for the oxygen isotope analyses
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