1,059 research outputs found

    DMAP as a Catalyst for Carbon Acylation: Elucidation of Mechanistic Pathway, Including Spectral Characterization of the Putative Reactive Intermediate

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    3-Phenylbenzofuranone, when deprotonated with sodium hydride, forms an extended enolate system which, when treated with excess alkyl chloroformates, affords only oxygen-acylated products, as opposed to the usually desired carbon-functionalized derivatives. It was discovered that such molecules, when treated with a catalytic amount of 4- (N, N-dimethylamino)pyridine (DMAP), rearrange quantitatively to the carbon acylated isomers. These migrations, which are accompanied by a deep blue color, are proposed to involve a reactive intermediate. This intermediate, which is postulated as an ion pair charge transfer (IPCT) complex, has been closely studied in order to gain a better understanding of the rearrangement mechanism. The spectral data was obtained while the rearrangement was going on, and the lifetime of the reactive intermediate was found to be less than 15 seconds. The rearrangement times and colors of this intriguing reaction were observed by substituting various substituents on the 3-Phenylbenzofuranone ring system. The λmax values of the reaction color, with various substituents on 3-Phenylbenzofuranone ring system, were correlated with the Hammett substituent constants

    An Analysis Of The Consequences Of Running Away Among Black And Hispanic Female Juvenile Offenders With An Emphasis On Future Orientation

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    Girls are prominent in the etiology of runaways due to having higher runaway rates than boys. While empirical studies of runaways have extensively focused on the causes of girls’ runaways, few studies shed light on the runaway consequences. Those studies that analyzed the consequences of a girl’s runaway have majorly stressed the delinquent outcomes. However, studies of runaway consequences have minimally paid attention to youth future orientation since future orientation is a vital factor in youth offending behavior. Furthermore, contextual background, such as runaway, influences the same future orientation. Therefore, this research explored the understudied relationship between the girl’s runaway consequences, future orientation, and offending behavior among female Black and Hispanic offenders. This quantitative research utilized a secondary dataset, Research on Pathways to Desistance [Maricopa County, AZ and Philadelphia County, PA]: Subject Measures, 2000-2010 from the Inter-university Consortium for Political and Social Research (ICPSR). This research examined three research questions. The first research question measured whether runaway girls significantly differed in their future orientation, exposure to violence, procedural justice, and certainty of sanctions perceptions than non-runaway girls. The second research question attempted to understand if there are any significant differences between runaway Black and Hispanic girls in their future orientation, exposure to violence, procedural justice, and certainty of sanctions perceptions. The third research question examined the interaction between exposure to violence, procedural justice, certainty of sanctions perceptions, and future orientation’s influence on runaway girls’ offending behavior. This research employed one-way ANOVA and Multiple Regression analysis to analyze the research questions. The research findings from one-way ANOVA identified no significant differences between runaway and non-runaway girls and Black and Hispanic girls in their future orientation, exposure to violence, procedural justice, and certainty of sanctions perceptions. The results from Multiple Regression analysis found a statistically significant influence of the interaction of exposure to violence and future orientation, and procedural justice and future orientation on runaway girls’ offending behavior. Keywords: runaway girls, future orientation, exposure to violence, procedural justice views, certainty of sanctions perceptions, self-reported offending behavio

    Agricultural marketing and agribusiness supply chain issues in developing economies: the case of fresh produce in Papua New Guinea

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    Large quantities of fresh produce can be grown in the Highlands provinces of Papua New Guinea, and this produce is then marketed to a range of markets, including the coastal cities of Port Moresby and Lae. However, it is often argued that the marketing system performs poorly, and various reasons for this are cited. In this paper, the results of a study on the marketing of smallholder produce originating in the Highlands provinces and destined for a range of markets, including the coastal cities, are presented. A defensible supply chain framework is used to evaluate a range of marketing issues and to evaluate the performance of the marketing system. The results of the study are refreshingly positive. It was found that the marketing system was remarkably vibrant, given the current level of market development in Papua New Guinea. It is characterised by entrepreneurial behaviour by the private sector, where businesses along the chain compete and innovate in order to expand their operations and meet the needs of the customers in their varied market segments. However, they are constrained in their endeavours by poor infrastructure, which raises their costs of doing business. It was concluded that the use of a Supply Chain Framework can yield a very robust and insightful understanding of the performance of the agricultural marketing system in developing economies

    Controlled Secret Sharing Protocol using a Quantum Cloning Circuit

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    We demonstrate the possibility of controlling the success probability of a secret sharing protocol using a quantum cloning circuit. The cloning circuit is used to clone the qubits containing the encoded information and {\em en route} to the intended receipients. The success probability of the protocol depends on the cloning parameters used to clone the qubits. We also establish a relation between the concurrence of initially prepared state, entanglement of the mixed state received by the receivers after cloning scheme and the cloning parameters of cloning machine.Comment: This is a modified version of the previous work quant-ph/arXiv:1011.286

    cmUML - A UML based framework for formal specification of concurrent, reactive systems

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    Complex software systems possess concurrent and reactive behaviors requiring precise specifications prior to development. Lamport's transition axiom method is a formal specification method which combines axiomatic and operational approaches. On the other hand Unified Modeling Language (UML), a de facto industry standard visual language, lacks suitable constructs and semantics regarding concurrency aspects. Though UML includes action semantics, its higher level constructs and object semantics are inconsistent. Motivated by Lamport's approach, this paper proposes a UML based specification framework 'cmUML' ('cm' for concurrent modules) for formal specification of concurrent, reactive systems without object level diagrams and OCL. The framework integrates higher level diagrams of UML and addresses various concurrency issues including exception handling. It combines UML-RT and UML// SPT profile as the latter defines a core package for concurrency and causality. Further the framework includes the characteristic safety and liveness aspects of concurrent systems. The proposed framework is in contrast with existing approaches based on low level primitives (semaphore, monitors). The paper includes several specification examples validating the proposed framework

    Hidden Order in Crackling Noise during Peeling of an Adhesive Tape

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    We address the long standing problem of recovering dynamical information from noisy acoustic emission signals arising from peeling of an adhesive tape subject to constant traction velocity. Using phase space reconstruction procedure we demonstrate the deterministic chaotic dynamics by establishing the existence of correlation dimension as also a positive Lyapunov exponent in a mid range of traction velocities. The results are explained on the basis of the model that also emphasizes the deterministic origin of acoustic emission by clarifying its connection to sticks-slip dynamics.Comment: 5 pages, 10 figure

    Implant isolation of Zn-doped GaAs epilayers: effects of ion species, doping concentration, and implantation temperature

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    The electrical isolation of Zn-doped GaAs layers grown by metalorganic chemical vapor deposition was studied using H, Li, C, and O ion implantation. The ion mass did not play a significant role in the stability of isolation, and a similar activation energy of ∼(0.63±0.03 eV) was obtained for isolation using either H or O ions. Furthermore, the isolation was stable against isochronal annealing up to 550 °C as long as the ion dose was 2–3.5 times the threshold dose for complete isolation, Dth, for the respective ion species. By studying the thermal stability and the temperature dependence of isolation, we have demonstrated the various stages leading to the production of stable isolation with the increasing dose of 2 MeV C ions. For ion doses less than 0.5Dth,point defects which are stable below 250 °C are responsible for the degradation of hole mobility and hole trapping. The stability of isolation is increased to ∼400 °C for a dose Dth due to the creation of defect pairs. Furthermore, the hopping conduction mechanism is already present in the damaged epilayer implanted to Dth. Higher order defect clusters or complexes, such as the arsenic antisite, AsGa, are responsible for the thermal stability of implantation isolation at 550 °C. The substrate temperature (−196–200 °C) does not have an effect on the isolation process further revealing that the stability of isolation is related to defect clusters and not point-like defects. An average number of eight carbon ions with energy of 2 MeV are required to compensate 100 holes, which provides a general guideline for choosing the ion dose required for the isolation of a GaAs layer doped with a known Zn concentration. A discussion of the results on the implantation isolation of p-GaAs previously reported in the literature is also included.P.N.K.D. acknowledges the Australian Research Council for financial support
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