Convective instability and mass transport of diffusion layers in a Hele-Shaw geometry

We consider experimentally the instability and mass transport of a porous-medium flow in a Hele-Shaw geometry. In an initially stable configuration, a lighter fluid (water) is located over a heavier fluid (propylene glycol). The fluids mix via diffusion with some regions of the resulting mixture being heavier than either pure fluid. Density-driven convection occurs with downward penetrating dense fingers that transport mass much more effectively than diffusion alone. We investigate the initial instability and the quasi steady state. The convective time and velocity scales, finger width, wave number selection, and normalized mass transport are determined for 6,000<Ra<90,000. The results have important implications for determining the time scales and rates of dissolution trapping of carbon dioxide in brine aquifers proposed as possible geologic repositories for sequestering carbon dioxide.Comment: 4 page, 3 figure

Structure analysis of the virtual Compton scattering amplitude at low energies

We analyze virtual Compton scattering off the nucleon at low energies in a covariant, model-independent formalism. We define a set of invariant functions which, once the irregular nucleon pole terms have been subtracted in a gauge-invariant fashion, is free of poles and kinematical zeros. The covariant treatment naturally allows one to implement the constraints due to Lorentz and gauge invariance, crossing symmetry, and the discrete symmetries. In particular, when applied to the $ep\to e'p'\gamma$ reaction, charge-conjugation symmetry in combination with nucleon crossing generates four relations among the ten originally proposed generalized polarizabilities of the nucleon.Comment: 19 pages, LaTeX2e/RevTeX, no figures, original sections IV.-VI. removed, to be discussed in a separate publication, none of the conclusions change

Generalized polarizabilities of the nucleon studied in the linear sigma model (II)

In a previous paper virtual Compton scattering off the nucleon has been investigated in the one-loop approximation of the linear sigma model in order to determine the 3 scalar generalized polarizabilities. We have now extended this work and calculated the 7 vector polarizabilities showing up in the spin-dependent amplitude of virtual Compton scattering. The results fulfill 3 model-independent constraints recently derived. Compared to the constituent quark model there exist enormous differences for some of the vector polarizabilities. At vanishing three-momentum of the virtual photon, the analytical results of the sigma model and of chiral perturbation theory can be related. The influence of the $\pi^{0}$ exchange in the $t$ channel has been discussed in some detail. Besides, the vector polarizabilities determine 2 linear combinations of the third order spin-polarizabilities appearing in real Compton scattering.Comment: 17 pages, 4 figures, latex2e (Revtex), submitted to Z. Phys.

Predictors of Two Kilometer Rowing Ergometer Time Trial Performance

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From the 'cinematic' to the 'anime-ic': Issues of movement in anime

This is the author's accepted manuscript. The final published article is available from the link below.This article explores the way that movement is formally depicted in anime. Drawing on Thomas Lamarre's concepts of the `cinematic' and the `anime-ic', the article interrogates further the differences in movement and action in anime from traditional filmic form. While often considered in terms of `flatness', anime offers spectacle, character development and, ironically, depth through the very form of movement put to use in such texts.The article questions whether the modes of address at work in anime are unique to this form of animation.Taking into account how the terms `cinematic' and `anime-ic' can be understood (and by extension the cinematic and animatic apparatus), the article also begins to explore how viewers might identify with such images

Differences Between an Aerobic and Yoga Group Exercise on Measures of Mood, Stress, and Group Cohesion

Please refer to the pdf version of the abstract located adjacent to the title

Generalized polarizabilities and the chiral structure of the nucleon

We discuss the virtual Compton scattering reaction $e^-p\to e^-p\gamma$ at low energies. We present results for the generalized polarizabilities of the nucleon obtained in heavy baryon chiral perturbation theory at $O(p^3)$.Comment: 5 pages, LaTex file, 1 postscript figure, uses ``espcrc1.sty'', talk given by S. Scherer at the 15th International Conference on Few Body Problems in Physics, Groningen, The Netherlands, 22-26 July 1997, to appear in the proceedings (Nucl. Phys. A

What Does it Take to Reduce Massachusetts Emissions 50% by 2030? Challenges Meeting Climate Goals Under Current Legislation (S.2500)

Executive Summary: To do its part in the global fight against climate change, Massachusetts must achieve net zero greenhouse gas emissions by mid-century, and aggressive intermediate goals are essential to ensure that the state is on track for net zero. Senate bill 2500, “An Act setting next generation climate policy,” stipulates that 2030 emissions must “not be less than 50% below the 1990 emissions level.” In 2017, Massachusetts carbon dioxide emissions were 22% below 1990 levels, so the state will need to reduce annual emissions by an additional 28% of 1990 levels by 2030. If enacted, S.2500 would give the state important new tools that would significantly reduce emissions. However, our analysis suggests that additional policies beyond those in S.2500 will likely be necessary to reliably achieve the 2030 goal of cutting emissions in half from 1990 levels. With no new policies enacted (but not accounting for COVID-19), we estimate that 2030 emissions will be roughly 35% below 1990 levels (Figure 1, BAU). We use a range of policy proposals to approximate the key policies in S.2500: the Transportation and Climate Initiative cap and invest program, a net zero stretch building code, and a moderate carbon price ($29/MT rising to$48 in 2030—roughly similar to one in a recent legislative proposal) in the residential, commercial, and industrial sectors. We use published modeling results to approximate these policies and estimate that they would reduce emissions by an additional 6% below 1990 levels (~41%). This leaves an emissions reductions shortfall of ~9% (or 8 million metric tons of CO2, roughly the equivalent of 1.7 million passenger vehicles) in 2030 (see Fig. 1). To reach a 50% reduction by 2030, Massachusetts could implement a higher carbon price (e.g. $58/MT rising to$95 by 2030), which would be possible under S.2500. Some (but not all) models suggest that a higher carbon price alone would be sufficient to reach 50% of 1990 levels by 2030. Another option (not in S.2500) is to enact an ambitious clean electricity standard to reduce electricity emissions. To ensure we reach the 2030 goal, robust policies will be needed in all major sectors of the state\u27s economy, with electricity sector decarbonization particularly important (Fig. 1, Stringent case)

Pulsed Doppler-free two-photon spectroscopy of polyatomic molecules

Doppler-free two-photon electronic spectra of a large polyatomic molecule are recorded for the first time with pulsed laser radiation of near Fourier-transform limited bandwidth (Δvnot, vert, similar100 MHz). The resolution obtained is sufficient to resolve individual rotational lines. Due to the high density of these rotational transitions a strong Doppler-broadened background is observed, which is, however, subtantially reduced by suitable choice of photon polarizations. Different vibronic bands of benzene (C6H6) are investigated and very accurate rotational constants are found

Pyridoxamine Traps Intermediates in Lipid Peroxidation Reactions in Vivo: Evidence on the Role of Lipids in Chemical Modification of Protein and Development of Diabetic Complications

Maillard or browning reactions between reducing sugars and protein lead to formation of advanced glycation end products (AGEs) and are thought to contribute to the pathogenesis of diabetic complications. AGE inhibitors such as aminoguanidine and pyridoxamine (PM) inhibit both the formation of AGEs and development of complications in animal models of diabetes. PM also inhibits the chemical modification of protein by advanced lipoxidation end products (ALEs) during lipid peroxidation reactions in vitro. We show here that several PM adducts, formed in incubations of PM with linoleate and arachidonate in vitro, are also excreted in the urine of PM-treated animals. The PM adducts N-nonanedioyl-PM (derived from linoleate), N-pentanedioyl-PM, N-pyrrolo-PM, and N-(2-formyl)-pyrrolo-PM (derived from arachidonate), and N-formyl-PM and N-hexanoyl-PM (derived from both fatty acids) were quantified by liquid chromatography-mass spectrometry analysis of rat urine. Levels of these adducts were increased 5-10-fold in the urine of PM-treated diabetic and hyperlipidemic rats, compared with control animals. We conclude that the PM functions, at least in part, by trapping intermediates in AGE/ALE formation and propose a mechanism for PM inhibition of AGE/ALE formation involving cleavage of alpha-dicarbonyl intermediates in glycoxidation and lipoxidation reactions. We also conclude that ALEs derived from polyunsaturated fatty acids are increased in diabetes and hyperlipidemia and may contribute to development of long term renal and vascular pathology in these diseases