1,527 research outputs found
Median Arcuate Ligament Syndrome: A Rare Cause of Abdominal Pain That is Difficult to Identify
Median arcuate ligament syndrome (MALS) is a rare disease that occurs when the celiac artery is compressed by the median arcuate ligament. Patients with MALS typically present with non-specific symptoms that overlap with more common diseases. As a result, patients may undergo extensive workup and unnecessary treatments before being properly diagnosed with MALS. In this case we present a 23-year-old female with chronic postprandial abdominal pain that persisted despite undergoing a cholecystectomy. This case highlights the symptoms and imaging findings needed to diagnose MALS and thus prevent unnecessary surgical interventions
Tracing the evolution of research in The Accounting Review through its leading authors: The 1946-1965 period
n order to better understand the development of accounting research, this paper examines the work of the leading authors of The Accounting Review (Leading Authors) during 1946-1965. An earlier study [Fleming, Graci and Thompson, 1990] concluded that the work of the Leading Authors during the 1926-1945 period was characterized by a practical orientation. The Accounting Review in many respects remained a practically oriented journal during 1946-1965. However, changes are evident that were contributing factors in the evolution of The Accounting Review into its current quantitative/empirical orientation
Characteristics of the work of leading authors of the Accounting Review, 1926-1945
The Accounting Review has changed dramatically over the years. The purpose of this study is to document these changes, putting into perspective the articles that are currently published in The Accounting Review. In particular, this study compares the work of those authors who had the most publications in The Accounting Review (Leading Authors) during 1926-1945 with more recent contributions. The results with respect to topic of articles, research methods, citations, and article length reflect the Leading Authors\u27 practical orientation, an attribute that is not particularly apparent in the work of current authors
Wetting and particle adsorption in nanoflows
Molecular dynamics simulations are used to study the behavior of
closely-fitting spherical and ellipsoidal particles moving through a
fluid-filled cylinder at nanometer scales. The particle, the cylinder wall and
the fluid solvent are all treated as atomic systems, and special attention is
given to the effects of varying the wetting properties of the fluid. Although
the modification of the solid-fluid interaction leads to significant changes in
the microstructure of the fluid, its transport properties are found to be the
same as in bulk. Independently of the shape and relative size of the particle,
we find two distinct regimes as a function of the degree of wetting, with a
sharp transition between them. In the case of a highly-wetting suspending
fluid, the particle moves through the cylinder with an average axial velocity
in agreement with that obtained from the solution of the continuum Stokes
equations. In contrast, in the case of less-wetting fluids, only the early-time
motion of the particle is consistent with continuum dynamics. At later times,
the particle is eventually adsorbed onto the wall and subsequently executes an
intermittent stick-slip motion.We show that van der Walls forces are the
dominant contribution to the particle adsorption phenomenon and that depletion
forces are weak enough to allow, in the highly-wetting situation, an initially
adsorbed particle to spontaneously desorb
Boundary conditions at a fluid - solid interface
We study the boundary conditions at a fluid-solid interface using molecular
dynamics simulations covering a broad range of fluid-solid interactions and
fluid densities, and both simple and chain-molecule fluids. The slip length is
shown to be independent of the type of flow, but rather is related to the fluid
organization near the solid, as governed by the fluid-solid molecular
interactions.Comment: REVtex, to appear in Physical Review Letter
Explanation at the opioid receptor level for differing toxicity of morphine and morphine 6-glucuronide.
The radiolabelled opioid receptor binding affinities of morphine and its active metabolite morphine 6-glucuronide at the total mu, mu 1, mu 2 and delta receptors were determined. Morphine 6-glucuronide was found to have a 4-fold lower affinity for the mu 2 receptor (IC50 17 nM and 82 nM for morphine and morphine 6-glucuronide respectively, P = 0.01), the receptor postulated to be responsible for mediating the respiratory depression and gastrointestinal effects after morphine. This provides a possible explanation for the reduced respiratory depression and vomiting seen following morphine 6-glucuronide in man. A similar reduction in affinity of morphine 6-glucuronide was seen at the total mu receptor whilst there was no significant difference seen at the mu 1 or delta receptor. Hence the increased analgesic potency of morphine 6-glucuronide over morphine remains unexplained
Quadrilateral-octagon coordinates for almost normal surfaces
Normal and almost normal surfaces are essential tools for algorithmic
3-manifold topology, but to use them requires exponentially slow enumeration
algorithms in a high-dimensional vector space. The quadrilateral coordinates of
Tollefson alleviate this problem considerably for normal surfaces, by reducing
the dimension of this vector space from 7n to 3n (where n is the complexity of
the underlying triangulation). Here we develop an analogous theory for
octagonal almost normal surfaces, using quadrilateral and octagon coordinates
to reduce this dimension from 10n to 6n. As an application, we show that
quadrilateral-octagon coordinates can be used exclusively in the streamlined
3-sphere recognition algorithm of Jaco, Rubinstein and Thompson, reducing
experimental running times by factors of thousands. We also introduce joint
coordinates, a system with only 3n dimensions for octagonal almost normal
surfaces that has appealing geometric properties.Comment: 34 pages, 20 figures; v2: Simplified the proof of Theorem 4.5 using
cohomology, plus other minor changes; v3: Minor housekeepin
Automated identification of multiple micro-organisms from resequencing DNA microarrays
There is an increasing recognition that detailed nucleic acid sequence information will be useful and even required in the diagnosis, treatment and surveillance of many significant pathogens. Because generating detailed information about pathogens leads to significantly larger amounts of data, it is necessary to develop automated analysis methods to reduce analysis time and to standardize identification criteria. This is especially important for multiple pathogen assays designed to reduce assay time and costs. In this paper, we present a successful algorithm for detecting pathogens and reporting the maximum level of detail possible using multi-pathogen resequencing microarrays. The algorithm filters the sequence of base calls from the microarray and finds entries in genetic databases that most closely match. Taxonomic databases are then used to relate these entries to each other so that the microorganism can be identified. Although developed using a resequencing microarray, the approach is applicable to any assay method that produces base call sequence information. The success and continued development of this approach means that a non-expert can now perform unassisted analysis of the results obtained from partial sequence data
Elevation change of the Greenland Ice Sheet due to surface mass balance and firn processes, 1960–2014
© The Author(s), 2015. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in The Cryosphere 9 (2015): 2009-2025, doi:10.5194/tc-9-2009-2015.Observed changes in the surface elevation of the Greenland Ice Sheet are caused by ice dynamics, basal elevation change, basal melt, surface mass balance (SMB) variability, and by compaction of the overlying firn. The last two contributions are quantified here using a firn model that includes compaction, meltwater percolation, and refreezing. The model is forced with surface mass fluxes and temperature from a regional climate model for the period 1960–2014. The model results agree with observations of surface density, density profiles from 62 firn cores, and altimetric observations from regions where ice-dynamical surface height changes are likely small. In areas with strong surface melt, the firn model overestimates density. We find that the firn layer in the high interior is generally thickening slowly (1–5 cm yr−1). In the percolation and ablation areas, firn and SMB processes account for a surface elevation lowering of up to 20–50 cm yr−1. Most of this firn-induced marginal thinning is caused by an increase in melt since the mid-1990s and partly compensated by an increase in the accumulation of fresh snow around most of the ice sheet. The total firn and ice volume change between 1980 and 2014 is estimated at −3295 ± 1030 km3 due to firn and SMB changes, corresponding to an ice-sheet average thinning of 1.96 ± 0.61 m. Most of this volume decrease occurred after 1995. The computed changes in surface elevation can be used to partition altimetrically observed volume change into surface mass balance and ice-dynamically related mass changes.P. Kuipers Munneke received financial
support from the Netherlands Polar Programme (NPP) of the
Netherlands Institute for Scientific Research (NWO). ECMWF at
Reading (UK) is acknowledged for use of the Cray supercomputing
system. The J. E. Box contribution is supported by
Det Frie Forskningsråd grant 4002-00234 and Geocenter Denmark
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