21,258 research outputs found

    Dicarba-closo-dodecarborane-containing half-sandwich complexes of ruthenium, osmium, rhodium and iridium : biological relevance and synthetic strategies

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    This review describes how the incorporation of dicarba-closo-dodecarboranes into half-sandwich complexes of ruthenium, osmium, rhodium and iridium might lead to the development of a new class of compounds with applications in medicine. Such a combination not only has unexplored potential in traditional areas such as Boron Neutron Capture Therapy agents, but also as pharmacophores for the targeting of biologically important proteins and the development of targeted drugs. The synthetic pathways used for the syntheses of dicarba-closo-dodecarboranes-containing half-sandwich complexes of ruthenium, osmium, rhodium and iridium are also reviewed. Complexes with a wide variety of geometries and characteristics can be prepared. Examples of addition reactions on the metal centre, B–H activation, transmetalation reactions and/or direct formation of metal–metal bonds are discussed (103 references)

    Laser radiation pressure slowing of a molecular beam

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    There is substantial interest in producing samples of ultracold molecules for possible applications in quantum computation, quantum simulation of condensed matter systems, precision measurements, controlled chemistry, and high precision spectroscopy. A crucial step to obtaining large samples of ultracold, trapped molecules is developing a means to bridge the gap between typical molecular source velocities (~150-600 m/s) and velocities for which trap loading or confinement is possible (~5-20 m/s). Here we show deceleration of a beam of neutral strontium monofluoride (SrF) molecules using radiative force. Under certain conditions, the deceleration results in a substantial flux of molecules with velocities <50 m/s. The observed slowing, from ~140 m/s, corresponds to scattering ~10000 photons. We also observe longitudinal velocity compression under different conditions. Combined with molecular laser cooling techniques, this lays the groundwork to create slow and cold molecular beams suitable for trap loading.Comment: 7 pages, 7 figures. Supplementary material updated

    On the parameterization dependence of the energy momentum tensor and the metric

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    We use results by Kirilin to show that in general relativity the nonleading terms in the energy-momentum tensor of a particle depends on the parameterization of the gravitational field. While the classical metric that is calculated from this source, used to define the leading long-distance corrections to the metric, also has a parameteriztion dependence, it can be removed by a coordinate change. Thus the classical observables are parameterization independent. The quantum effects that emerge within the same calculation of the metric also depend on the parameterization and a full quantum calculation requires the inclusion of further diagrams. However, within a given parameterization the quantum effects calculated by us in a previous paper are well defined. Flaws of Kirilin's proposed alternate metric definition are described and we explain why the diagrams that we calculated are the appropriate ones.Comment: 8 pages, 2 figure

    Designing Catastrophe Bonds to Securitize Systemic Risks in Agriculture: The Case of Georgia Cotton

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    This article makes an initial attempt to design catastrophe (CAT) bond products for agriculture and examines the potential of these instruments as mechanisms for transferring agricultural risks from insurance companies to investors/speculators in the global capital market. The case of Georgia cotton is considered as a specific example. The CAT bond contracts are based on percentage deviations of realized state average yields relative to the long-run average. The contracts are priced using historical state-level cotton yield data. The principal finding of the study is that the proposed CAT bonds demonstrate potential as risk transfer mechanisms for crop insurance companies.CAT bonds, catastrophe bond pricing, catastrophe insurance, disaster risk, reinsurance, risk securitization, Risk and Uncertainty,

    RENTAL PREMIUMS FOR SHARE VERSUS CASH LEASES

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    Non-risk factors primarily determine the probability of paying positive premiums to landowners for bearing greater risk under crop share versus cash leasing arrangements. The trends toward higher cash rent levels on larger farms may indicate that higher cash rent is a bidding strategy to control additional leased acreage and perhaps to avoid management sharing with multiple landlords. Expansion of farm size may be more important than soil productivity in negotiating higher cash rents, due to potential size economies and under utilized machinery investments.Land Economics/Use,

    Manual of Criminal Law and Procedure

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    Intended to aid to Alaska law enforcement officers in the performance of their duties in the field, this manual was designed to provide brief, quick access to major points of substantive and procedural criminal law. The manual contained discussion and procedural guidelines for investigatory stops, identification procedures including line-ups, arrest, search and seizure, interrogation, as well as discussion of justification for the use of nondeadly and deadly force whether by peace officers or civilians, culpability, entrapment, trial preparation, and media relations. The section on substantive criminal law deals with a selection of crimes most likely to be encountered by "street" officers as defined with the recently enacted Revised Alaska Criminal Code (effective January 1, 1980), desribing elements of each crime, investigative hints, and differences with previous provisions of the criminal code, where relevant.Alaska Department of Law Grant No. 78-A-014Introduction / Criminal Procedures / Substantive Criminal Law / Justification / Culpability / Entrapment / Trial Preparation / Media Relations / Appendice

    Determinants of Activity Levels in African Americans With Mild Cognitive Impairment.

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    Engaging in cognitive, social, and physical activities may prevent cognitive decline. In a sample of older African Americans with mild cognitive impairment (MCI; N=221), we investigated the cross-sectional relationships between activity levels and participants\u27 demographic, clinical, and neuropsychological characteristics. The average age of participants was 75.4 years (SD, 7.0); 177 (80.1%) were women. Participation in cognitive/social activities was positively associated with education, depression, literacy, mobility, instrumental activities of daily living (IADL), verbal learning, and subcomponents of executive function. A linear regression identified IADLs, education, depression, and verbal learning as independent predictors. Participation in physical activities was positively associated with sex, depression, IADLs, and subcomponents of executive function. An ordinal regression identified executive function and depression as independent correlates. These data suggest that unique characteristics are associated with cognitive/social and physical activities in older African Americans with MCI. These characteristics, coupled with low activity levels, may increase the risk of progression from MCI to dementia. Culturally relevant behavioral interventions to reduce cognitive decline in this high-risk population are needed

    A TRANSACTION COST ECONOMICS AND PROPERTY RIGHTS THEORY APPROACH TO FARMLAND LEASE PREFERENCES

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    Numerous theoretical approaches to farmland leasing contract choice have been developed with little consistent empirical support, particularly for the Corn Belt. A unique theoretical approach to explaining farmers' lease preferences is presented, using a combination of transaction cost economics and property rights theory. Results demonstrate that both transactional and certain producer characteristics are important motivators of contract choice.Land Economics/Use,
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