5,534 research outputs found

    Quasi-Chemical and Structural Analysis of Polarizable Anion Hydration

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    Quasi-chemical theory is utilized to analyze the roles of solute polarization and size in determining the structure and thermodynamics of bulk anion hydration for the Hofmeister series Cl^-, Br^-, and I^-. Excellent agreement with experiment is obtained for whole salt hydration free energies using the polarizable AMOEBA force field. The quasi-chemical approach exactly partitions the solvation free energy into inner-shell, outer-shell packing, and outer-shell long-ranged contributions by means of a hard-sphere condition. Small conditioning radii, even well inside the first maximum of the ion-water(oxygen) radial distribution function, result in Gaussian behavior for the long-ranged contribution that dominates the ion hydration free energy. The spatial partitioning allows for a mean-field treatment of the long-ranged contribution, leading to a natural division into first-order electrostatic, induction, and van der Waals terms. The induction piece exhibits the strongest ion polarizability dependence, while the larger-magnitude first-order electrostatic piece yields an opposing but weaker polarizability dependence. In addition, a structural analysis is performed to examine the solvation anisotropy around the anions. As opposed to the hydration free energies, the solvation anisotropy depends more on ion polarizability than on ion size: increased polarizability leads to increased anisotropy. The water dipole moments near the ion are similar in magnitude to bulk water, while the ion dipole moments are found to be significantly larger than those observed in quantum mechanical studies. Possible impacts of the observed over-polarization of the ions on simulated anion surface segregation are discussed.Comment: slight revision, in press at J. Chem. Phy

    “And to the Republic for Which It Stands”: Guaranteeing a Republican Form of Government

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    Most scholars who have addressed voter initiatives suggest only that the Guarantee Clause requires that the Supreme Court take a more active role in reviewing the constitutionality of state initiative measures. In contrast, we argue in this Essay that the Guarantee Clause establishes a per se prohibition against state initiatives. Part I of this Essay briefly examines the historical origins of the Guarantee Clause and the Founders’ apprehensions of direct democracy. Part II observes how modern state initiatives provide contemporary illustrations of the Founders’ philosophical concerns about direct democracy. Part III concludes that state initiative measures constitute per se violations of the Guarantee Clause and, accordingly, must be summarily rejected. In so concluding, this Essay rejects proposals that courts review direct legislation or certain genres of direct legislation under heightened scrutiny

    Consumer Experience of Animal Crossing: New Horizons Players During Covid-19 Lockdowns

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    Project of Merit Winner The Consumer Experience of Animal Crossing: New Horizons Players During COVID-19 Lockdowns Raquel Holliday, David Rogers, Dr. Natalie A. Mitchell Abstract Due to COVID-19 global lockdowns in March 2020, Nintendo’s spring release game, Animal Crossing: New Horizons (ACHN), garnered massive popularity and unprecedented sales. The simulation game involves creating a new life on an island. As life events such as high school and college graduations, proms, weddings were cancelled, and consumers experienced anguish due to isolation, consumers took to ACHN to recreate the same life events within a digital world. Instant success led to broad acceptance with consumers sharing examples of replicated life events in gameplay on social media sites. In this study, we investigated the influence of ACHN on culture, how consumers engage and connect with others, and their adjustment to COVID-19 lockdowns through their gameplay as shared on Twitter. These inquiries center around digital virtual consumption, which is heightened during a time of a global pandemic lockdown. The research team used a combined method approach which involved gameplay and a textual analysis of 1,000 Twitter posts to assess insights and images related to ACHN gameplay. Reoccurring themes of real-life simulation, co-creation and extended-self were found in the data. An unexpected finding included a first-ever in-game political campaign and many brand integrations. Insights developed from this research indicates how deprivation and scarcity within a global pandemic yields social connection, and creative, replicated lifestyles within simulated video games, affording players full control of their mediated worlds, despite external factors producing uncertainties

    The Construction of Innovativeness Scales

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    Salicylaldehyde hydrazones: buttressing of outer sphere hydrogen-bonding and copper-extraction properties

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    Salicylaldehyde hydrazones are weaker copper extractants than their oxime derivatives, which are used in hydrometallurgical processes to recover ~20 % of the world’s copper. Their strength, based on the extraction equilibrium constant Ke, can be increased by nearly three orders of magnitude by incorporating electron-withdrawing or hydrogen-bond acceptor groups (X) ortho to the phenolic OH group of the salicylaldehyde unit. Density functional theory calculations suggest that the effects of the 3-X substituents arise from a combination of their influence on the acidity of the phenol in the pH-dependent equilibrium, Cu2+ + 2Lorg ⇌ [Cu(L–H)2]org + 2H+, and on their ability to ‘buttress’ interligand hydrogen bonding by interacting with the hydrazone N–H donor group. X-ray crystal structure determination and computed structures indicate that in both the solid state and the gas phase, coordinated hydrazone groups are less planar than coordinated oximes and this has an adverse effect on intramolecular hydrogen-bond formation to the neighbouring phenolate oxygen atoms

    Radio Astronomy

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    Contains reports on three research projects.National Aeronautics and Space Administration (Grant NsG-419)National Aeronautics and Space Administration (Grant NsG-250-62)U. S. Air Force under Contract AF 19(628)-500Lincoln Laboratory, Purchase Order DDL BB-10

    Global data for ecology and epidemiology: a novel algorithm for temporal Fourier processing MODIS data

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    Background. Remotely-sensed environmental data from earth-orbiting satellites are increasingly used to model the distribution and abundance of both plant and animal species, especially those of economic or conservation importance. Time series of data from the MODerate-resolution Imaging Spectroradiometer (MODIS) sensors on-board NASA's Terra and Aqua satellites offer the potential to capture environmental thermal and vegetation seasonality, through temporal Fourier analysis, more accurately than was previously possible using the NOAA Advanced Very High Resolution Radiometer (AVHRR) sensor data. MODIS data are composited over 8- or 16-day time intervals that pose unique problems for temporal Fourier analysis. Applying standard techniques to MODIS data can introduce errors of up to 30% in the estimation of the amplitudes and phases of the Fourier harmonics. Methodology/Principal Findings. We present a novel spline-based algorithm that overcomes the processing problems of composited MODIS data. The algorithm is tested on artificial data generated using randomly selected values of both amplitudes and phases, and provides an accurate estimate of the input variables under all conditions. The algorithm was then applied to produce layers that capture the seasonality in MODIS data for the period from 2001 to 2005. Conclusions/Significance. Global temporal Fourier processed images of 1 km MODIS data for Middle Infrared Reflectance, day- and night-time Land Surface Temperature (LST), Normalised Difference Vegetation Index (NDVI), and Enhanced Vegetation Index (EVI) are presented for ecological and epidemiological applications. The finer spatial and temporal resolution, combined with the greater geolocational and spectral accuracy of the MODIS instruments, compared with previous multi-temporal data sets, mean that these data may be used with greater confidence in species' distribution modelling
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