Variational rotating solutions to non-isentropic Euler-Poisson equations with prescribed total mass

Before theoretical ideas in this subject can be compared with observational data, it is necessary to consider the properties of galaxies that are likely to be relics of their formation. Most astronomers would agree that the list of important parameters should be headed by the total mass M, energy E and angular momentum J. Next on the list should probably be the relative contributions to these quantities from the disc and bulge components of galaxies and denoted D/B for the mass ratio. They can be estimated from the median (i.e. half-mass) radius R, velocity dispersion σ and rotation velocity v of each component, either through the virial theorem or through the luminosity L and an assumed value of M/L. As a first approximation, it is reasonable to suppose that galaxies of a given disc-to-bulge ratio or morphological type form a sequence with mass as the fundamental parameter. The comparison of theory with data is further simplified by considering the extreme cases of ellipticals, with D/B << 1, and late-type spirals, with D/B >> 1. The approach outlined below is to explore the consequences of relaxing in succession the constraints that E, J and M be conserved during the collapse of proto-galaxies. In this article I concentrate on theories that are based on some form of hierarchical clustering because the pancake and related theories are not yet refined enough for a detailed confrontation with observations.

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Quantitative Determination of the Surface Distribution of Supported Metal Nanoparticles: A Laser Ablation–ICP–MS Based Approach

Chemosensors ◽

10.3390/chemosensors9040077 ◽

2021 ◽

Vol 9 (4) ◽

pp. 77

Author(s):

Davide Spanu ◽

Gilberto Binda ◽

Marcello Marelli ◽

Laura Rampazzi ◽

Sandro Recchia ◽

...

Keyword(s):

Spatial Distribution ◽

Laser Ablation ◽

Quantitative Determination ◽

Metal Nanoparticles ◽

Total Mass ◽

Functional Materials ◽

Metal Extraction ◽

Ms Analysis ◽

Icp Ms

A laser ablation–inductively coupled plasma–mass spectrometry (LA–ICP–MS) based method is proposed for the quantitative determination of the spatial distribution of metal nanoparticles (NPs) supported on planar substrates. The surface is sampled using tailored ablation patterns and the data are used to define three-dimensional functions describing the spatial distribution of NPs. The volume integrals of such interpolated surfaces are calibrated to obtain the mass distribution of Ag NPs by correlation with the total mass of metal as determined by metal extraction and ICP–MS analysis. Once this mass calibration is carried out on a sacrificial sample, quantifications can be performed over multiple samples by a simple micro-destructive LA–ICP–MS analysis without requiring the extraction/dissolution of metal NPs. The proposed approach is here tested using a model sample consisting of a low-density polyethylene (LDPE) disk decorated with silver NPs, achieving high spatial resolution over cm2-sized samples and very high sensitivity. The developed method is accordingly a useful analytical tool for applications requiring both the total mass and the spatial distribution of metal NPs to be determined without damaging the sample surface (e.g., composite functional materials and NPs, decorated catalysts or electrodic materials).

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Body Mass and Body Composition Changes over 7 Years in a Male Professional Rugby Union Team

International Journal of Sports Medicine ◽

10.1055/a-1403-2906 ◽

2021 ◽

Author(s):

Clíodhna McHugh ◽

Karen Hind ◽

Aoife O'Halloran ◽

Daniel Davey ◽

Gareth Farrell ◽

...

Keyword(s):

Body Composition ◽

Body Mass ◽

Body Fat ◽

Lean Mass ◽

Total Mass ◽

Rugby Union ◽

Body Fat Percentage ◽

Fat Percentage ◽

Dxa Scans ◽

Composition Changes

AbstractThe purpose of this study was to investigate longitudinal body mass and body composition changes in one professional rugby union team (n=123), (i) according to position [forwards (n=58) versus backs (n=65)], analysis of players with 6 consecutive seasons of DXA scans (n=21) and, (iii) to examine differences by playing status [academy and international], over 7 years. Players [mean age: 26.8 y, body mass index: 28.9+kg.m2] received DXA scans at fourtime points within each year. A modest (but non-significant) increase in mean total mass (0.8 kg) for professional players was reflected by increased lean mass and reduced body fat mass. At all-time points, forwards had a significantly greater total mass, lean mass and body fat percentage compared to backs (p<0.05). Academy players demonstrated increased total and lean mass and decreased body fat percentage over the first 3 years of senior rugby, although this was not significant. Senior and academy international players had greater lean mass and lower body fat percentage (p<0.05) than non-international counterparts. Despite modest increases in total mass; reflected by increased lean mass and reduced fat mass, no significant changes in body mass or body composition, irrespective of playing position were apparent over 7 years.

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Electrodiffusion Phenomena in Neuroscience and the Nernst–Planck–Poisson Equations

Electrochem ◽

10.3390/electrochem2020014 ◽

2021 ◽

Vol 2 (2) ◽

pp. 197-215

Author(s):

Jerzy J. Jasielec

Keyword(s):

Electrical Potential ◽

Signal Propagation ◽

Liquid Junction Potential ◽

Liquid Junction ◽

Patch Clamp Technique ◽

Poisson Equations ◽

Cellular Environment ◽

Electrochemical Transport ◽

Insight Into ◽

Junction Potential

This work is aimed to give an electrochemical insight into the ionic transport phenomena in the cellular environment of organized brain tissue. The Nernst–Planck–Poisson (NPP) model is presented, and its applications in the description of electrodiffusion phenomena relevant in nanoscale neurophysiology are reviewed. These phenomena include: the signal propagation in neurons, the liquid junction potential in extracellular space, electrochemical transport in ion channels, the electrical potential distortions invisible to patch-clamp technique, and calcium transport through mitochondrial membrane. The limitations, as well as the extensions of the NPP model that allow us to overcome these limitations, are also discussed.

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Bayesian constraints on the origin and geology of exo-planetary material using a population of externally polluted white dwarfs

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab736 ◽

2021 ◽

Author(s):

John H D Harrison ◽

Amy Bonsor ◽

Mihkel Kama ◽

Andrew M Buchan ◽

Simon Blouin ◽

...

Keyword(s):

Solar System ◽

White Dwarf ◽

Bayesian Model ◽

Total Mass ◽

White Dwarfs ◽

Bulk Composition ◽

Planetary Systems ◽

The Moon ◽

Planetary Bodies ◽

Nearby Stars

Abstract White dwarfs that have accreted planetary bodies are a powerful probe of the bulk composition of exoplanetary material. In this paper, we present a Bayesian model to explain the abundances observed in the atmospheres of 202 DZ white dwarfs by considering the heating, geochemical differentiation, and collisional processes experienced by the planetary bodies accreted, as well as gravitational sinking. The majority (>60%) of systems are consistent with the accretion of primitive material. We attribute the small spread in refractory abundances observed to a similar spread in the initial planet-forming material, as seen in the compositions of nearby stars. A range in Na abundances in the pollutant material is attributed to a range in formation temperatures from below 1,000 K to higher than 1,400 K, suggesting that pollutant material arrives in white dwarf atmospheres from a variety of radial locations. We also find that Solar System-like differentiation is common place in exo-planetary systems. Extreme siderophile (Fe, Ni or Cr) abundances in 8 systems require the accretion of a core-rich fragment of a larger differentiated body to at least a 3σ significance, whilst one system shows evidence that it accreted a crust-rich fragment. In systems where the abundances suggest that accretion has finished (13/202), the total mass accreted can be calculated. The 13 systems are estimated to have accreted masses ranging from the mass of the Moon to half that of Vesta. Our analysis suggests that accretion continues for 11Myrs on average.

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Mass outflow of the X-ray emission line gas in NGC 4151

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320001660 ◽

2020 ◽

Vol 15 (S359) ◽

pp. 131-135

Author(s):

S. B. Kraemer ◽

T. J. Turner ◽

D. M. Crenshaw ◽

H. R. Schmitt ◽

M. Revalski ◽

...

Keyword(s):

Emission Line ◽

Total Mass ◽

High Energy ◽

Model Parameters ◽

Zeroth Order ◽

Space Telescope ◽

X Ray ◽

Ngc 4151 ◽

Outflow Rate ◽

Mass Outflow

AbstractWe have analyzed Chandra/High Energy Transmission Grating spectra of the X-ray emission line gas in the Seyfert galaxy NGC 4151. The zeroth-order spectral images show extended H- and He-like O and Ne, up to a distance r ˜ 200 pc from the nucleus. Using the 1st-order spectra, we measure an average line velocity ˜230 km s–1, suggesting significant outflow of X-ray gas. We generated Cloudy photoionization models to fit the 1st-order spectra; the fit required three distinct emission-line components. To estimate the total mass of ionized gas (M) and the mass outflow rates, we applied the model parameters to fit the zeroth-order emission-line profiles of Ne IX and Ne X. We determined an M ≍ 5.4 × 105Mʘ. Assuming the same kinematic profile as that for the [O III] gas, derived from our analysis of Hubble Space Telescope/Space Telescope Imaging Spectrograph spectra, the peak X-ray mass outflow rate is approximately 1.8 Mʘ yr–1, at r ˜ 150 pc. The total mass and mass outflow rates are similar to those determined using [O III], implying that the X-ray gas is a major outflow component. However, unlike the optical outflows, the X-ray emitting mass outflow rate does not drop off at r > 100pc, which suggests that it may have a greater impact on the host galaxy.

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Evaluation of annual and semiannual total mass variation over the Mediterranean Sea from satellite data

Arabian Journal of Geosciences ◽

10.1007/s12517-021-07190-4 ◽

2021 ◽

Vol 14 (10) ◽

Author(s):

Nadia AbouAly ◽

Karem Abdelmohsen ◽

Matthias Becker ◽

Abdel-Monem S. Mohamed ◽

Abotalib Z. Abotalib ◽

...

Keyword(s):

Mediterranean Sea ◽

Satellite Data ◽

Total Mass ◽

Mass Variation ◽

The Mediterranean

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Aperture synthesis CS and 98 GHz continuum observations of protostellar IRAS sources in Taurus

Symposium - International Astronomical Union ◽

10.1017/s0074180900239673 ◽

1991 ◽

Vol 147 ◽

pp. 353-356

Author(s):

N. Ohashi ◽

R. Kawabe ◽

M. Hayashi ◽

M. Ishiguro

Keyword(s):

Molecular Cloud ◽

Total Mass ◽

T Tauri Stars ◽

Continuum Emission ◽

Beam Size ◽

Dust Grains ◽

Dynamical Mass ◽

T Tauri ◽

Cloud Cores ◽

The Continuum

The CS (J = 2 — 1) line and 98 GHz continuum emission have been observed for 11 protostellar IRAS sources in the Taurus molecular cloud with resolutions of 2.6″−8.8″ (360 AU—1200 AU) using the Nobeyama Millimeter Array (NMA). The CS emission is detected only toward embedded sources, while the continuum emission from dust grains is detected only toward visible T Tauri stars except for one embedded source, L1551-IRS5. This suggests that the dust grains around the embedded sources do not centrally concentrate enough to be detected with our sensitivity (∼4 m Jy r.m.s), while dust grains in disks around the T Tauri stars have enough total mass to be detected with the NMA. The molecular cloud cores around the embedded sources are moderately extended and dense enough to be detected in CS, while gas disks around the T Tauri are not detected because the radius of such gas disks may be smaller than 70 (50 K/Tex) AU. These results imply that the total amount of matter within the NMA beam size must increase when the central objects evolve into T Tauri stars from embedded sources, suggesting that the compact and highly dense disks around T Tauri stars are formed by the dynamical mass accretion during the embedded protostar phase.

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