Conductive organic polymers are most commonly generated from the oxidation or reduction of conjugated polymers. Although such conjugated polymers are typically viewed as modern materials, the ...earliest examples of these polymers date back to the early 19th century. The modern era of conjugated polymers began with the first reports of their conductive nature in the early 1960s. However, it was advances in the 1970s that brought particular focus to these materials with the first example of conductivity values in the metallic regime, for which the 2000 Nobel Prize in Chemistry was awarded to Hideki Shirakawa, Alan MacDiarmid, and Alan Heeger. Unfortunately, the historical narrative of these polymers is currently quite muddled in the primary literature, with various inaccuracies commonly propagated. In an effort to present a more accurate account as a resource for the field, the present report will review the first 150 years of the four primary parent polymers−polyaniline, polypyrrole, polyacetylene, and polythiophene, from their early origins in 1834 to their rapid development in the mid‐1980s.
Conductive organic polymers, from the oxidation or reduction of conjugated polymers, are viewed as modern materials, yet conjugated polymers date back to the 19th century. Here, the first 150 years of polyaniline, polypyrrole, polyacetylene, and polythiophene are reviewed from their origins in 1834 to their rapid development in the mid‐1980s.
The surprising story of how George Washington, Alexander Hamilton, John Adams, and Thomas Jefferson came to despair for the future of the nation they had created Americans seldom deify their Founding ...Fathers any longer, but they do still tend to venerate the Constitution and the republican government that the founders created. Strikingly, the founders themselves were far less confident in what they had wrought, particularly by the end of their lives. In fact, most of them—including George Washington, Alexander Hamilton, John Adams, and Thomas Jefferson—came to deem America's constitutional experiment an utter failure that was unlikely to last beyond their own generation. Fears of a Setting Sun is the first book to tell the fascinating and too-little-known story of the founders' disillusionment.As Dennis Rasmussen shows, the founders' pessimism had a variety of sources: Washington lost his faith in America's political system above all because of the rise of partisanship, Hamilton because he felt that the federal government was too weak, Adams because he believed that the people lacked civic virtue, and Jefferson because of sectional divisions laid bare by the spread of slavery. The one major founder who retained his faith in America's constitutional order to the end was James Madison, and the book also explores why he remained relatively optimistic when so many of his compatriots did not. As much as Americans today may worry about their country's future, Rasmussen reveals, the founders faced even graver problems and harbored even deeper misgivings.A vividly written account of a chapter of American history that has received too little attention, Fears of a Setting Sun will change the way that you look at the American founding, the Constitution, and indeed the United States itself.
Adam Smith is popularly regarded as the ideological forefather of laissez-faire capitalism, while Rousseau is seen as the passionate advocate of the life of virtue in small, harmonious communities ...and as a sharp critic of the ills of commercial society. But, in fact, Smith had many of the same worries about commercial society that Rousseau did and was strongly influenced by his critique. In this first book-length comparative study of these leading eighteenth-century thinkers, Dennis Rasmussen highlights Smith’s sympathy with Rousseau’s concerns and analyzes in depth the ways in which Smith crafted his arguments to defend commercial society against these charges. These arguments, Rasmussen emphasizes, were pragmatic in nature, not ideological: it was Smith’s view that, all things considered, commercial society offered more benefits than the alternatives. Just because of this pragmatic orientation, Smith’s approach can be useful to us in assessing the pros and cons of commercial society today and thus contributes to a debate that is too much dominated by both dogmatic critics and doctrinaire champions of our modern commercial society.
Abstract
Gastrointestinal (GI) tract diseases are responsible for substantial morbidity and mortality worldwide, including colorectal cancer, which has shown a rising incidence among adults younger ...than 50. Although this could be alleviated by regular screening, only a small percentage of those at risk are screened comprehensively, due to shortcomings in accuracy and patient acceptance. To address these challenges, we designed an artificial intelligence (AI)-empowered wireless video endoscopic capsule that surpasses the performance of the existing solutions by featuring, among others: (1) real-time image processing using onboard deep neural networks (DNN), (2) enhanced visualization of the mucous layer by deploying both white-light and narrow-band imaging, (3) on-the-go task modification and DNN update using over-the-air-programming and (4) bi-directional communication with patient’s personal electronic devices to report important findings. We tested our solution in an in vivo setting, by administrating our endoscopic capsule to a pig under general anesthesia. All novel features, successfully implemented on a single platform, were validated. Our study lays the groundwork for clinically implementing a new generation of endoscopic capsules, which will significantly improve early diagnosis of upper and lower GI tract diseases.
Intrachannel nonlinearity is considered a major distortion in high-capacity transmission systems particular for the case without inline optical chromatic dispersion compensation. In this paper, a ...low-complexity intrachannel nonlinear compensator operating at the symbol rate is proposed based on the nonlinear perturbation predistortion for the dual-polarization quadrature phase-shift keying (DP-QPSK) systems. Compared with the widely studied backpropagation algorithm, the proposed algorithm achieves comparable performance with significantly reduced complexity and halved sampling speed in digital signal processing and digital-to-analog converters. The proposed algorithm is demonstrated in a 43 Gb/s DP-QPSK transmission experiment over 1500 km. In addition to the experimental demonstration, numerical simulation verifies that the proposed algorithm is quite robust by tolerating significant uncertainties of link parameters and span-by-span inhomogeneity in the links.
The catastrophic disruption of the L chondrite parent body in the asteroid belt c. 470 Ma initiated a prolonged meteorite bombardment of Earth that started in the Ordovician and continues today. ...Abundant L chondrite meteorites in Middle Ordovician strata have been interpreted to be the consequence of the asteroid breakup event. Here we report a zircon U-Pb date of 467.50±0.28 Ma from a distinct bed within the meteorite-bearing interval of southern Sweden that, combined with published cosmic-ray exposure ages of co-occurring meteoritic material, provides a precise age for the L chondrite breakup at 468.0±0.3 Ma. The new zircon date requires significant revision of the Ordovician timescale that has implications for the understanding of the astrogeobiologic development during this period. It has been suggested that the Middle Ordovician meteorite bombardment played a crucial role in the Great Ordovician Biodiversification Event, but this study shows that the two phenomena were unrelated.
Physicists have long wondered whether the gravitational interactions between matter and antimatter might be different from those between matter and itself. Although there are many indirect ...indications that no such differences exist and that the weak equivalence principle holds, there have been no direct, free-fall style, experimental tests of gravity on antimatter. Here we describe a novel direct test methodology; we search for a propensity for antihydrogen atoms to fall downward when released from the ALPHA antihydrogen trap. In the absence of systematic errors, we can reject ratios of the gravitational to inertial mass of antihydrogen >75 at a statistical significance level of 5%; worst-case systematic errors increase the minimum rejection ratio to 110. A similar search places somewhat tighter bounds on a negative gravitational mass, that is, on antigravity. This methodology, coupled with ongoing experimental improvements, should allow us to bound the ratio within the more interesting near equivalence regime.
The story of the greatest of all philosophical friendships-and how it influenced modern thought
David Hume is widely regarded as the most important philosopher ever to write in English, but during ...his lifetime he was attacked as "the Great Infidel" for his skeptical religious views and deemed unfit to teach the young. In contrast, Adam Smith was a revered professor of moral philosophy, and is now often hailed as the founding father of capitalism. Remarkably, the two were best friends for most of their adult lives, sharing what Dennis Rasmussen calls the greatest of all philosophical friendships.The Infidel and the Professoris the first book to tell the fascinating story of the friendship of these towering Enlightenment thinkers-and how it influenced their world-changing ideas.
The book follows Hume and Smith's relationship from their first meeting in 1749 until Hume's death in 1776. It describes how they commented on each other's writings, supported each other's careers and literary ambitions, and advised each other on personal matters, most notably after Hume's quarrel with Jean-Jacques Rousseau. Members of a vibrant intellectual scene in Enlightenment Scotland, Hume and Smith made many of the same friends (and enemies), joined the same clubs, and were interested in many of the same subjects well beyond philosophy and economics-from psychology and history to politics and Britain's conflict with the American colonies. The book reveals that Smith's private religious views were considerably closer to Hume's public ones than is usually believed. It also shows that Hume contributed more to economics-and Smith contributed more to philosophy-than is generally recognized.
Vividly written,The Infidel and the Professoris a compelling account of a great friendship that had great consequences for modern thought.
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