11,421 research outputs found

    Double Charge Exchange And Configuration Mixing

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    The energy dependence of forward pion double charge exchange reactions on light nuclei is studied for both the Ground State transition and the Double-Isobaric-Analog-State transitions. A common characteristic of these double reactions is a resonance-like peak around 50 MeV pion lab energy. This peak arises naturally in a two-step process in the conventional pion-nucleon system with proper handling of nuclear structure and pion distortion. A comparison among the results of different nuclear structure models demonstrates the effects of configuration mixing. The angular distribution is used to fix the single particle wave function.Comment: Added 1 figure (now 8) corrected references and various other change

    Discurso de investidura como Doctor Honoris Causa del Prof. D. Sir. John H. Elliot

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    Día de la Universidad. 25/01/08. Discurso Sir John Elliott

    Learning About Assessment: An Evaluation of a Ten-State Effort to Build Assessment Capacity in High Schools

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    In 2006, the State of Delaware and the Council of Chief State School Officers (CCSSO) partnered with the Consortium for Policy Research in Education (CPRE) to conduct an evaluation of a ten-state initiative that sought to enhance assessment practices at the high school level. This effort aimed to help states, districts, and schools build familiarity with instruction that uses assessment as part of the learning process, a practice known as assessment for learning. This report focuses primarily on the third goal of this project, the creation and function of teacher learning teams focused on assessment for learning

    An XRF Compositional Analysis of Opaque White Glass Beads from 17th-Century Mission Santa Catalina de Guale, Georgia

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    Previous analyses of the elemental composition of white glass beads have shown that the opacifier used during glass manufacture is temporally diagnostic, with a transition from tin to antimony to arsenic to fluorine. To date, most researchers using this fact for chronological purposes have focused on British, Dutch, and French contact sites in the northeastern United States and Canada. Many of these studies have relied on expensive, and sometimes minimally destructive, techniques. X-ray fluorescence spectrometry is a widely available, non-destructive technique that can be used to identify glass opacifiers extremely rapidly and inexpensively. This technique was used to analyze 783 specimens of four varieties of drawn white glass beads from burial contexts at Mission Santa Catalina de Guale, Georgia, demonstrating that the “opacifer-dating” method is also applicable to Spanish colonial sites in the southeastern United States

    Season in Hell: Understanding Bosina\u27s War

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    Evaluation of Resiliency in a Wide-area Backup Protection System via Model Checking

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    Modern civilization relies heavily on having access to reliable power sources. Recent history has shown that present day protection systems are not adequate. Numerous backup protection (BP) systems have been proposed to mitigate the impact of primary protection system failures. Many of these novel BP systems rely on autonomous agents communicating via wide-area networks. These systems are highly complex and their control logic is based on distributed computing. Model checking has been shown to be a powerful tool in analyzing the behavior of distributed systems. In this research the model checker SPIN is used to evaluate the resiliency of an agent based wide-area backup protection (WABP) system. All combinations of WABP system component malfunctions that lead to system failure are identified and classified. The results of this research indicate that the WABP system evaluated is more resilient to component malfunctions than previously reported. Possible WABP system improvements are introduced as well

    For Love or For Profit? – Crafting a Suitable Securities Framework for Initial Coin Offerings

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    The spectacle of Bitcoin has largely overshadowed the development of the cryptocurrency’s underlying structure – the blockchain. The blockchain is a type of digital ledger that performs a number of traditional record-keeping functions in a more efficient and reliable manner. Organizations around the globe continue to invest heavily in blockchain technology for a myriad of purposes. To fund these innovative projects, many organizations hold an Initial Coin Offering (“ICO”) in which “tokens” -- a blockchain’s primary means of exchanging value, proving ownership, and/or paying for network services -- are sold to purchasers in exchange for U.S. dollars. In many ways, ICOs are the modern equivalent of a traditional initial public offering (“IPO”). Tokens are often bought as a financial investment, with purchasers hoping to capitalize on cryptocurrency mania and reap a large return. Indeed, some ICOs have exploited overzealous investors by holding fraudulent ICOs without any real intention of developing a functioning blockchain network. As a result, the Securities and Exchange Commission largely regulates ICOs in the same manner as IPOs, imposing stringent reporting requirements and liability on startups and developers. However, these bad apples are in the minority and moreover, certain tokens sold through ICOs do not meet the classic definition of a “security.” Utility tokens, in particular, are functionally distinct from a traditional security with any rise in value being incidental to the token’s primary utility. Treating all crypto-tokens sold through ICOs as securities stifles development by imposing onerous requirements upon novice developers. Current securities law exemptions are inadequate and given the popularity and success of many ICOs, their offerings should not be forced into poorly tailored regulations. The SEC should acknowledge the unique nature of certain blockchain tokens and provide tailored guidance for future ICOs if this burgeoning industry is to flourish

    The 22-Class Tower of Q(5460)\mathbb{Q}(\sqrt{-5460})

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    The seminal papers in the field of root-discriminant bounds are those of Odlyzko and Martinet. Both papers include the question of whether the field Q(5460)\mathbb{Q}(\sqrt{-5460}) has finite or infinite 22-class tower. This is a critical case that will either substantially lower the best known upper bound for lim inf of root-discriminants (if infinite) or else give a counter-example to what is often termed Martinet's conjecture or question (if finite). Using extensive computation and introducing some new techniques, we give strong evidence that the tower is in fact finite, establishing other properties of its Galois group en route
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