3,566 research outputs found
Survey of hydrogen production and utilization methods. Volume 1: Executive summary
The use of hydrogen as a synthetic fuel is considered. Processes for the production of hydrogen are described along with the present and future industrial uses of hydrogen as a fuel and as a chemical feedstock. Novel and unconventional hydrogen-production techniques are evaluated, with emphasis placed on thermochemical and electrolytic processes. Potential uses for hydrogen as a fuel in industrial and residential applications are identified and reviewed in the context of anticipated U.S. energy supplies and demands. A detailed plan for the period from 1975 to 1980 prepared for research on and development of hydrogen as an energy carrier is included
Dynamics of coreless vortices and rotation-induced dissipation peak in superfluid films on rotating porous substrates
We analyze dynamics of 3D coreless vortices in superfluid films covering
porous substrates. The 3D vortex dynamics is derived from the 2D dynamics of
the film. The motion of a 3D vortex is a sequence of jumps between neighboring
substrate cells, which can be described, nevertheless, in terms of
quasi-continuous motion with average vortex velocity. The vortex velocity is
derived from the dissociation rate of vortex-antivortex pairs in a 2D film,
which was developed in the past on the basis of the Kosterlitz-Thouless theory.
The theory explains the rotation-induced dissipation peak in torsion-oscillator
experiments on He films on rotating porous substrates and can be used in
the analysis of other phenomena related to vortex motion in films on porous
substrates.Comment: 8 pages, 3 figures submitted to Phys. Rev.
Fiduciary Law in Financial Regulation
This chapter explores the application of fiduciary duties to regulated financial firms and financial services. At first blush, the need for such a chapter might strike some as surprising in that fiduciary duties and systems of financial regulation can be conceptualized as governing distinctive and nonoverlapping spheres: fiduciary duties police private activity through open-ended, judicially defined standards imposed on an ex post basis, whereas financial regulations set largely mandatory, ex ante obligations for regulated entities under supervisory systems established in legislation and implemented through expert administrative agencies. Yet, as the chapter documents, fiduciary duties often do overlap with systems of financial regulation. In many regulatory contexts, fiduciary duties arise as a complement to, or sometimes substitute for, other mechanisms of financial regulation. Moreover, the interactions between fiduciary duties and systems of financial regulation generate a host of recurring and challenging interpretative issues. The chapter explores the reasons fiduciary duties arise so frequently in the field of financial regulation and provides a structured account of how the principles of fiduciary duties interact with the more rule-based legal requirements that characterize financial regulation. As grist for this undertaking the chapter focuses on a set of roughly two dozen judicial decisions and administrative rulings to illustrate its claims
Transition from KPZ to Tilted Interface Critical Behavior in a Solvable Asymmetric Avalanche Model
We use a discrete-time formulation to study the asymmetric avalanche process
[Phys. Rev. Lett. vol. 87, 084301 (2001)] on a finite ring and obtain an exact
expression for the average avalanche size of particles as a function of
toppling probabilities depending on parameters and . By mapping
the model below and above the critical line onto driven interface problems, we
show how different regimes of avalanches may lead to different types of
critical interface behavior characterized by either annealed or quenched
disorders and obtain exactly the related critical exponents which violate a
well-known scaling relation when .Comment: 10 page
Calibration of colour gradient bias in shear measurement using HST/CANDELS data
Accurate shape measurements are essential to infer cosmological parameters from large area weak gravitational lensing studies. The compact diffraction-limited point-spread function (PSF) in space-based observations is greatly beneficial, but its chromaticity for a broad band observation can lead to new subtle effects that could hitherto be ignored: the PSF of a galaxy is no longer uniquely defined and spatial variations in the colours of galaxies result in biases in the inferred lensing signal. Taking Euclid as a reference, we show that this colourgradient bias (CG bias) can be quantified with high accuracy using available multi-colour Hubble Space Telescope (HST) data. In particular we study how noise in the HST observations might impact such measurements and find this to be negligible. We determine the CG bias using HST observations in the F606W and F814W filters and observe a correlation with the colour, in line with expectations, whereas the dependence with redshift is weak. The biases for individual galaxies are generally well below 1%, which may be reduced further using morphological information from the Euclid data. Our results demonstrate that CG bias should not be ignored, but it is possible to determine its amplitude with sufficient precision, so that it will not significantly bias the weak lensing measurements using Euclid data
Pan-human consensus genome significantly improves the accuracy of RNA-seq analyses
The Human Reference Genome serves as the foundation for modern genomic analyses. However, in its present form, it does not adequately represent the vast genetic diversity of the human population. In this study, we explored the consensus genome as a potential successor of the current reference genome and assessed its effect on the accuracy of RNA-seq read alignment. To find the best haploid genome representation, we constructed consensus genomes at the pan-human, superpopulation, and population levels, using variant information from The 1000 Genomes Project Consortium. Using personal haploid genomes as the ground truth, we compared mapping errors for real RNA-seq reads aligned to the consensus genomes versus the reference genome. For reads overlapping homozygous variants, we found that the mapping error decreased by a factor of approximately two to three when the reference was replaced with the pan-human consensus genome. We also found that using more population-specific consensuses resulted in little to no increase over using the pan-human consensus, suggesting a limit in the utility of incorporating a more specific genomic variation. Replacing the reference with consensus genomes impacts functional analyses, such as differential expressions of isoforms, genes, and splice junctions
Beyond Unprecedented S3 Ep4: Inflation: Not Dead Yet
Over the past 24 months, inflation has soared in the United States, the United Kingdom, and elsewhere. Huw Pill, Chief Economist and Executive Director for Monetary Analysis and research for the Bank of England, discusses the factors driving high inflation and efforts to curb rising prices. (This episode was recorded on April 18, 2023.)https://scholarship.law.columbia.edu/beyond_unprecedented_3/1004/thumbnail.jp
Beyond Unprecedented S3 Ep3: Boardroom Ballot Battles and the Universal Proxy
The U.S. Securities and Exchange Commission recently adopted rules mandating the use of universal proxy cards for electing directors to the boards of public companies. Broadridge Financial Solutions Chief Legal Officer Keir Gumbs discusses the new rules and the potential repercussions of universal proxy card voting for investors and corporations.https://scholarship.law.columbia.edu/beyond_unprecedented_3/1003/thumbnail.jp
Effect of left atrial and ventricular abnormalities on renal transplant recipient outcome—a single-center study
Background:
Premature cardiovascular (CV) death is the commonest cause of death in renal transplant recipients. Abnormalities of left ventricular (LV) structure (collectively termed uremic cardiomyopathy) and left atrial (LA) dilation, a marker of fluid status and diastolic function, are risk factors for reduced survival in patients with end stage renal disease (ESRD). In the present analysis, we studied the impact of pre-transplant LA and LV abnormalities on survival after successful renal transplantation (RT).<p></p>
Methods:
One hundred nineteen renal transplant recipients (first transplant, deceased donors) underwent cardiovascular MRI (CMR) as part of CV screening prior to inclusion on the waiting list. Data regarding transplant function and patient survival after transplantation were collected.<p></p>
Results:
Median post-transplant follow-up was 4.3 years (interquartile range (IQR) 1.9, 6.2). During the post-transplant period, 13 patients returned to dialysis after graft failure and 23 patients died with a functioning graft. Survival analyses, censoring for patients returning to dialysis, showed that pre-transplant LV hypertrophy and elevated LA volume were significantly associated with reduced survival after transplantation. Multivariate Cox regression analyses demonstrated that longer waiting time, poorer transplant function, presence of LV hypertrophy and higher LA volume on screening CMR and female sex were independent predictors of death in patients with a functioning transplant.<p></p>
Conclusions:
Presence of LVH and higher LA volume are significant, independent predictors of death in patients who are wait-listed and proceed with renal transplantation.<p></p>
METHODS:
One hundred nineteen renal transplant recipients (first transplant, deceased donors) underwent cardiovascular MRI (CMR) as part of CV screening prior to inclusion on the waiting list. Data regarding transplant function and patient survival after transplantation were collected.<p></p>
RESULTS:
Median post-transplant follow-up was 4.3 years (interquartile range (IQR) 1.9, 6.2). During the post-transplant period, 13 patients returned to dialysis after graft failure and 23 patients died with a functioning graft. Survival analyses, censoring for patients returning to dialysis, showed that pre-transplant LV hypertrophy and elevated LA volume were significantly associated with reduced survival after transplantation. Multivariate Cox regression analyses demonstrated that longer waiting time, poorer transplant function, presence of LV hypertrophy and higher LA volume on screening CMR and female sex were independent predictors of death in patients with a functioning transplant.<p></p>
CONCLUSIONS:
Presence of LVH and higher LA volume are significant, independent predictors of death in patients who are wait-listed and proceed with renal transplantation
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