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ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMechanism of Aryl Chloride Amination: Base-Induced Oxidative AdditionLuis M. Alcazar-Roman and John F. HartwigView Author Information Department of Chemistry, Yale University P.O. Box 208107, New Haven, Connecticut 06520-8107 Cite this: J. Am. Chem. Soc. 2001, 123, 51, 12905–12906Publication Date (Web):November 29, 2001Publication History Received25 June 2001Revised31 August 2001Published online29 November 2001Published inissue 1 December 2001https://pubs.acs.org/doi/10.1021/ja016491khttps://doi.org/10.1021/ja016491krapid-communicationACS PublicationsCopyright © 2001 American Chemical SocietyRequest reuse permissionsArticle Views3207Altmetric-Citations120LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (2)»Supporting Information Supporting Information SUBJECTS:Anions,Aromatic compounds,Catalysts,Order,Oxidative addition Get e-Alerts

The dollar's dominance of international transactions and role as a reserve currency is an exorbitant privilege that is a burden as well as a blessing for the US. It achieved this dominance early in the twentieth century, quite quickly in fact; it may also see that status change equally quickly were the world to move to a multipolar system of currencies. Among the most likely candidates for reserve currencies in such a world are the dollar, the euro, and the Chinese renminbi, Barry Eichengreen explained in his Butlin Lecture earlier in 2011.

This chapter contains sections titled: Overview of Research on the Central Atlantic Magmatic Province

Exotic mineralization is a complex hydrochemical process linking supergene enrichment, lateral transport, and precipitation of oxide minerals in the drainage network of a porphyry deposit. At the El Salvador porphyry deposit in northern Chile the majority of the exotic ore comprised a mixture of copper-bearing manganese oxyhydrates termed copper wad. X-ray diffraction, scanning electron microscopy, and electron probe microanalysis show that the wad is composed of copper-bearing cryptomelane [K1-2(Mn3+Mn4+)8O16 • x H2O] and birnessite [K0.33\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(Mn_{7}^{3.9+}\) \end{document}O14 • 7H2O] structures. These natural occurrences within the exotic ore provide the opportunity to directly date the formation of these deposits using recent advances in 40Ar/39Ar geochronology of supergene K-Mn oxides formed by weathering. A suite of copper-bearing cryptomelane and birnessite samples from exotic deposits within the El Salvador district were characterized and dated by 40Ar/39Ar laser step heating. Supergene alunite [KAl3(SO4)2(OH)6] found in paleospring feeder systems leading from the source zones of outward to the exotic mineralization was dated to independently constrain the age of exotic ore formation. Although the Ar retentivity of the layered birnessite structure has been questioned by others, the Ar retentivity of these samples is thought to be a function of their natural preservation and limited postcrystallization ground-water interaction in the hyperarid Atacama desert. The 40Ar/39Ar analytical results show that Ar and/or K losses after crystallization, excess 40Ar, and 39Ar recoil do not pose significant problems; therefore, in the context of exotic deposits within hyperarid environments this dating method is applicable to both cryptomelane and birnessite within wad. The 40Ar/39Ar dating of exotic mineralization at El Salvador indicates that supergene and exotic mineralization processes were active at ~35 Ma, about 5 m.y. after the emplacement of hydrothermal mineralization, and continued until the middle Miocene. The majority of exotic mineralization extends from the Oligocene-Miocene (24 Ma) boundary through the middle Miocene (11 Ma) and relates to supergene fluid emanating in multiple directions from the source of in Indio Muerto, which represents a topographic high above the exotic deposits. One reconnaissance date of exotic mineralization at the Chuquicamata porphyry deposit yielded an age of 17.03 ± 0.03 Ma coincident with the known supergene alunite dates for this deposit. Reconnaissance dating at Exotica-Mina Sur and El Abra proved problematic due to the presence of contaminant silicate minerals within the wad. Ages derived here for exotic mineralization are similar to the known supergene ages throughout northern Chile. The dates indicate that supergene exotic mineralization began at the Eocene-Oligocene boundary and continued through the Oligocene, eventually ceasing in the middle Miocene due to desiccation of the Atacama desert. A series of 10-cm-thick supergene alunite veins were microsampled across their widths and dated to address the kinetics of alunite vein growth. Apparent growth rates of the veins vary from 71 to 100 mm/m.y. in the horizontal direction to 24 mm/m.y. in the vertical, presumably caused by differences in pressure regimes due to their orientation.

Cellular Nonlinear/neural Network (CNN) technology is both a revolutionary concept and an experimentally proven new computing paradigm. Analogic cellular computers based on CNNs are set to change the way analog signals are processed and are paving the way to an analog computing industry. This unique undergraduate level textbook includes many examples and exercises, including CNN simulator and development software accessible via the Internet. It is an ideal introduction to CNNs and analogic cellular computing for students, researchers and engineers from a wide range of disciplines. Although its prime focus is on visual computing, the concepts and techniques described in the book will be of great interest to those working in other areas of research including modeling of biological, chemical and physical processes. Leon Chua, co-inventor of the CNN, and Tamás Roska are both highly respected pioneers in the field.

The Paraná-Etendeka flood volcanic event produced ∼1.5 × 10 6 cubic kilometers of volcanic rocks, ranging from basalts to rhyolites, before the separation of South America and Africa during the Cretaceous period. New 40 Ar/ 39 Ar data combined with earlier paleomagnetic results indicate that Paraná flood volcanism in southern Brazil began at 133 ± 1 million years ago and lasted less than 1 million years. The implied mean eruption rate on the order of 1.5 cubic kilometers per year is consistent with a mantle plume origin for the event and is comparable to eruption rates determined for other well-documented continental flood volcanic events. Paraná flood volcanism occurred before the initiation of sea floor spreading in the South Atlantic and was probably precipitated by uplift and weakening of the lithosphere by the Tristan da Cunha plume. The Parana event postdates most current estimates for the age of the faunal mass extinction associated with the Jurassic-Cretaceous boundary.

A stoichiometric model of metabolism was developed to describe the balance of metabolic reactions during steady-state growth of Escherichia coli on glucose (or metabolic intermediates) and mineral salts. The model incorporates 153 reversible and 147 irreversible reactions and 289 metabolites from several metabolic data bases for the biosynthesis of the macromolecular precursors, coenzymes, and prosthetic groups necessary for synthesis of all cellular macromolecules. Correlations describing how the cellular composition changes with growth rate were developed from experimental data and were used to calculate the drain of precursors to macromolecules, coenzymes, and prosthetic groups from the metabolic network for the synthesis of those macromolecules at a specific growth rate. Energy requirements for macromolecular polymerization and proofreading, transport of metabolites, and maintenance of transmembrane gradients were included in the model rather than a lumped maintenance energy term. The underdetermined set of equations was solved using the Simplex algorithm, employing realistic objective functions and constraints; the drain of precursors, coenzymes, and prosthetic groups and the energy requirements for the synthesis of macromolecules served as the primary set of constraints. The model accurately predicted experimentally determined metabolic fluxes for aerobic growth on acetate or acetate plus glucose. In addition, the model predicted the genetic and metabolic regulation that must occur for growth under different conditions, such as the opening of the glyoxylate shunt during growth on acetate and the branching of the tricarboxylic acid cycle under anaerobic growth. Sensitivity analyses were performed to determine the flexibility of pathways and the effects of different rates and growth conditions on the distribution of fluxes. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 398-421, 1997.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPrediction of low occupancy sorption of alkanes in silicaliteR. Larry. June, Alexis T. Bell, and Doros N. TheodorouCite this: J. Phys. Chem. 1990, 94, 4, 1508–1516Publication Date (Print):February 1, 1990Publication History Published online1 May 2002Published inissue 1 February 1990https://pubs.acs.org/doi/10.1021/j100367a056https://doi.org/10.1021/j100367a056research-articleACS PublicationsRequest reuse permissionsArticle Views595Altmetric-Citations193LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access options Get e-Alerts

Resumen fr: La sociologie comparee de la structure, la dynamique et l´experience de la relegation urbaine aux Etats-Unis et dans les principaux pays de l’Union eur...