185 research outputs found
Hepatocellular Carcinoma Arising in Non-Cirrhotic Haemochromatosis
Hepatocellular carcinoma arising in a patient with genetic haemachromatosis, without cirrhosis, has
only been described once previously. We present a patient with a 15 year history of genetic
haemachromatosis who underwent resection of a hepatocellular carcinoma in a liver with normal
architecture
Measurement of Liver Blood Flow: A Review
The study of hepatic haemodynamics is of importance in understanding both hepatic physiology and
disease processes as well as assessing the effects of portosystemic shunting and liver transplantation. The
liver has the most complicated circulation of any organ and many physiological and pathological
processes can affect it1,2. This review surveys the methods available for assessing liver blood flow,
examines the different parameters being measured and outlines problems of applicability and interpretation
for each technique
Condition Indices as Surrogates of Energy Density and Lipid Content in Juveniles of Three Fish Species
To guide the selection of condition indices for juvenile fishes, we compared the ability of several indirect condition indices (those based on length-mass relationships, the hepatosomatic index, and relative lipid estimates from the Distell fish fatmeter) to assess energy density and lipid content of Summer Flounder Paralichthys dentatus, Striped BassMorone saxatilis, and Atlantic Croakers Micropogonias undulatus. These species use estuarine areas as nurseries, but they have different life history strategies and ecological niches that affect their energy storage strategies. We tested hypotheses that differences in the distribution and role of lipids as energy stores among species would influence the suitability of condition indices for estimating energy and lipid content. Length-based indices were most suitable for estimating energy and lipid content of juvenile Summer Flounder and Striped Bass, suggesting that length-based indices may be appropriate for juveniles that store energy as proteins (i.e., juveniles with low lipid content). The fatmeter suitably predicted energy and lipid content of Atlantic Croakers, indicating its potential for assessing condition of juveniles that store lipids for migration and that display a high range of observed lipid content. Even though a small size range was examined, fish length improved predictions of energy and lipid content for some of the indirect condition indices for Atlantic Croakers and Summer Flounder, suggesting that fish length should be considered when developing relationships among measures of condition. The selection of condition indices should be tailored to the life stage and species of interest based on the energy and lipid storage strategies used by the fish
The angular-momentum flux in the solar wind observed during Solar Orbiter's first orbit
Aims: We present the first measurements of the angular-momentum flux in the solar wind recorded by the Solar Orbiter spacecraft.
Our aim is to validate these measurements to support future studies of the Sunâs angular-momentum loss.
Methods: We combined 60-min averages of the proton bulk moments and the magnetic field measured by the Solar Wind Analyser
(SWA) and the magnetometer (MAG) onboard Solar Orbiter. We calculated the angular-momentum flux per solid-angle element using
data from the first orbit of the missionâs cruise phase in 2020. We separated the contributions from protons and from magnetic stresses
to the total angular-momentum flux.
Results: The angular-momentum flux varies significantly over time. The particle contribution typically dominates over the magneticfield contribution during our measurement interval. The total angular-momentum flux shows the largest variation and is typically anticorrelated with the radial solar-wind speed. We identify a compression region, potentially associated with a co-rotating interaction
region or a coronal mass ejection, which leads to a significant localised increase in the angular-momentum flux, albeit without a
significant increase in the angular momentum per unit mass. We repeated our analysis using the density estimate from the Radio and
Plasma Waves (RPW) instrument. Using this independent method, we find a decrease in the peaks of positive angular-momentum
flux, but otherwise, our results remain consistent.
Conclusions: Our results largely agree with previous measurements of the solar windâs angular-momentum flux in terms of amplitude,
variability, and dependence on radial solar-wind bulk speed. Our analysis highlights the potential for more detailed future studies of
the solar windâs angular momentum and its other large-scale properties with data from Solar Orbiter. We emphasise the need for
studying the radial evolution and latitudinal dependence of the angular-momentum flux in combination with data from Parker Solar
Probe and other assets at heliocentric distances of 1 au and beyond
SPH study of the evolution of waterâwater interfaces in dam break flows
The mixing process of upstream and downstream waters in the dam break flow could
generate significant ecological impact on the downstream reaches and influence the
environmental damages caused by the dam break flood. This is not easily investigated with
the analytical and numerical models based on the grid method due to the large deformation of
free surface and the water-water interface. In this paper, a weakly compressible Smoothed
Particle Hydrodynamics (WCSPH) solver is used to study the advection and mixing process
of the water bodies in two-dimensional dam-break flows over a wet bed. The numerical
results of the mixing dynamics immediately after the release of the dam water are found to
agree satisfactorily with the published experimental and numerical results. Then further
investigations are carried out to study the interface development at the later stage of dambreak
flows in a long channel. The analyses concentrate on the evolution of the interface at
different ratios between the upstream and downstream water depths. The potential
capabilities of the mesh-free SPH modelling approach for predicting the detailed
development of the water-water interfaces are fully demonstrated.The first author acknowledges the Jafar Studentship during her PhD study at the University of
Cambridge. The other authors acknowledge the support of the
Major State Basic Research Development Program (973) of China (No. 2013CB036402),
Open Fund of the State Key Laboratory of Hydraulics and Mountain River Engineering,
Sichuan University (SKHL1404; SKHL1409), Start-up Grant for the Young Teachers of
Sichuan University (2014SCU11056) and National Science and Technology Support Plan
(2012BAB0513B0).This is the accepted manuscript. The final version is available at http://link.springer.com/article/10.1007%2Fs11069-015-1726-6
Evolution of the parsec-scale structure of PKS 1934-638 revisited: first science with the ASKAP and New Zealand telescopes
Magnetic reconnection as a mechanism to produce multiple protonpopulations and beams locally in the solar wind
Context. Spacecraft observations early revealed frequent multiple proton populations in the solar wind. Decades of research on their origin have focused on processes such as magnetic reconnection in the low corona and wave-particle interactions in the corona and locally in the solar wind.Aims.This study aims to highlight that multiple proton populations and beams are also produced by magnetic reconnection occurring locally in the solar wind. Methods. We use high resolution Solar Orbiter proton velocity distribution function measurements, complemented by electron and magnetic field data, to analyze the association of multiple proton populations and beams with magnetic reconnection during a period of slow Alfv\'enic solar wind on 16 July 2020. Results. At least 6 reconnecting current sheets with associated multiple proton populations and beams, including a case of magnetic reconnection at a switchback boundary, are found during this day. This represents 2% of the measured distribution functions. We discuss how this proportion may be underestimated, and how it may depend on solar wind type and distance from the Sun. Conclusions. Although suggesting a likely small contribution, but which remains to be quantitatively assessed, Solar Orbiter observations show that magnetic reconnection must be considered as one of the mechanisms that produce multiple proton populations and beams locally in the solar wind
Parker Solar Probe Enters the Magnetically Dominated Solar Corona
International audienceThe high temperatures and strong magnetic fields of the solar corona form streams of solar wind that expand through the Solar System into interstellar space. At 09:33 UT on 28 April 2021 Parker Solar Probe entered the magnetized atmosphere of the Sun 13 million km above the photosphere, crossing below the Alfvén critical surface for five hours into plasma in casual contact with the Sun with an Alfvén Mach number of 0.79 and magnetic pressure dominating both ion and electron pressure. The spectrum of turbulence below the Alfvén critical surface is reported. Magnetic mapping suggests the region was a steady flow emerging on rapidly expanding coronal magnetic field lines lying above a pseudostreamer. The sub-Alfvénic nature of the flow may be due to suppressed magnetic reconnection at the base of the pseudostreamer, as evidenced by unusually low densities in this region and the magnetic mapping
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