Local Volume Illumination

2006 ◽  
pp. 103-138
Keyword(s):  
Local Volume

scholarly journals Thalamic morphology predicts the onset of freezing of gait in Parkinson’s disease

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Nicholas D’Cruz ◽  
Griet Vervoort ◽  
Sima Chalavi ◽  
Bauke W. Dijkstra ◽  
Moran Gilat ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Resting State ◽  
Freezing Of Gait ◽  
Study Entry ◽  
Resting State Functional Connectivity ◽  
Behavioral Correlates ◽  
Local Volume ◽  
Linear Evolution ◽  
Risk Of Falls

AbstractThe onset of freezing of gait (FOG) in Parkinson’s disease (PD) is a critical milestone, marked by a higher risk of falls and reduced quality of life. FOG is associated with alterations in subcortical neural circuits, yet no study has assessed whether subcortical morphology can predict the onset of clinical FOG. In this prospective multimodal neuroimaging cohort study, we performed vertex-based analysis of grey matter morphology in fifty-seven individuals with PD at study entry and two years later. We also explored the behavioral correlates and resting-state functional connectivity related to these local volume differences. At study entry, we found that freezers (N = 12) and persons who developed FOG during the course of the study (converters) (N = 9) showed local inflations in bilateral thalamus in contrast to persons who did not (non-converters) (N = 36). Longitudinally, converters (N = 7) also showed local inflation in the left thalamus, as compared to non-converters (N = 36). A model including sex, daily levodopa equivalent dose, and local thalamic inflation predicted conversion with good accuracy (AUC: 0.87, sensitivity: 88.9%, specificity: 77.8%). Exploratory analyses showed that local thalamic inflations were associated with larger medial thalamic sub-nuclei volumes and better cognitive performance. Resting-state analyses further revealed that converters had stronger thalamo-cortical coupling with limbic and cognitive regions pre-conversion, with a marked reduction in coupling over the two years. Finally, validation using the PPMI cohort suggested FOG-specific non-linear evolution of thalamic local volume. These findings provide markers of, and deeper insights into conversion to FOG, which may foster earlier intervention and better mobility for persons with PD.

Permeability in the Mushy Zone

2010 ◽  
Vol 649 ◽  
pp. 399-408 ◽  
Author(s):  
R.G. Erdmann ◽  
D.R. Poirier ◽  
A.G. Hendrick
Keyword(s):  
Mushy Zone ◽  
Volume Fraction ◽  
Primary Dendrite ◽  
Fluid Velocity ◽  
Interdendritic Liquid ◽  
Creeping Flow ◽  
Liquid Region ◽  
Local Volume ◽  
Local Volume Fraction ◽  
Deterministic Function

When modeled at macroscopic length scales, the complex dendritic network in the solid-plus-liquid region of a solidifying alloy (the “mushy zone”) has been modeled as a continuum based on the theory of porous media. The most important property of a porous medium is its permeability, which relates the macroscopic pressure gradient to the throughput of fluid flow. Knowledge of the permeability of the mushy zone as a function of the local volume-fraction of liquid and other morphological parameters is thus essential to successfully modeling the flow of interdendritic liquid during alloy solidification. In current continuum models, the permeability of the mushy zone is given as a deterministic function of (1) the local volume fraction of liquid and (2) a characteristic length scale such as the primary dendrite arm spacing or the reciprocal of the specific surface area of the solid-liquid interface. Here we first provide a broad overview of the experimental data, mesoscale numerical flow simulations, and resulting correlations for the deterministic permeability of both equiaxed and columnar mushy zones. A extended view of permeability in mushy zones which includes the stochastic nature of permeability is discussed. This viewpoint is the result of performing extensive numerical simulations of creeping flow through random microstructures. The permeabilities obtained from these simulations are random functions with spatial autocorrelation structures, and variations in the local permeability are shown to have dramatic effects on the flow patterns observed in such microstructures. Specifically, it is found that “lightning-like” patterns emerge in the fluid velocity and that the flows in such geometries are strongly sensitive to small variations in the solid structure. We conclude with a comparison of deterministic and stochastic permeabilities which suggests the importance of incorporating stochastic descriptions of the permeability of the mushy zone in solidification modeling.

Local volume inversion and corner effects in triangular gate-all-around MOSFETs

2006 ◽  
Author(s):  
Kirsten Moselund ◽  
Didier Bouvet ◽  
Lucas Tschuor ◽  
Vincent Pott ◽  
Paolo Dainesi ◽  
...  
Keyword(s):  
Local Volume ◽  
Corner Effects

scholarly journals Probing the Dusty Stellar Populations of the Local Volume Galaxies withJWST/MIRI

2017 ◽  
Vol 841 (1) ◽  
pp. 15 ◽  
Author(s):  
Olivia C. Jones ◽  
Margaret Meixner ◽  
Kay Justtanont ◽  
Alistair Glasse
Keyword(s):  
Stellar Populations ◽  
Local Volume

scholarly journals The disc-averaged star formation relation for Local Volume dwarf galaxies

2018 ◽  
Vol 480 (1) ◽  
pp. 210-222 ◽  
Author(s):  
Á R López-Sánchez ◽  
C D P Lagos ◽  
T Young ◽  
H Jerjen
Keyword(s):  
Star Formation ◽  
Dwarf Galaxies ◽  
Local Volume

scholarly journals The DECam Local Volume Exploration Survey: Overview and First Data Release

2021 ◽  
Vol 256 (1) ◽  
pp. 2
Author(s):  
A. Drlica-Wagner ◽  
J. L. Carlin ◽  
D. L. Nidever ◽  
P. S. Ferguson ◽  
N. Kuropatkin ◽  
...  
Keyword(s):  
Local Volume ◽  
Data Release ◽  
Volume Exploration

scholarly journals Abundance of dwarf galaxies around low-mass spiral galaxies in the Local Volume

2020 ◽  
Vol 644 ◽  
pp. A91
Author(s):  
Oliver Müller ◽  
Helmut Jerjen
Keyword(s):  
Surface Brightness ◽  
Spiral Galaxies ◽  
Dwarf Galaxies ◽  
Dwarf Galaxy ◽  
Current Model ◽  
Host Galaxies ◽  
Local Volume ◽  
Satellite Problem ◽  
Low Mass ◽  
Crucial Test

The abundance of satellite dwarf galaxies has long been considered a crucial test for the current model of cosmology leading to the well-known missing satellite problem. Recent advances in simulations and observations have allowed the study of dwarf galaxies around host galaxies in more detail. Using the Dark Energy Camera we surveyed a 72 deg2 area of the nearby Sculptor group, also encompassing the two low-mass Local Volume galaxies NGC 24 and NGC 45 residing behind the group, to search for as yet undetected dwarf galaxies. Apart from the previously known dwarf galaxies we found only two new candidates down to a 3σ surface brightness detection limit of 27.4 r mag arcsec−2. Both systems are in projection close to NGC 24. However, one of these candidates could be an ultra-diffuse galaxy associated with a background galaxy. We compared the number of known dwarf galaxy candidates around NGC 24, NGC 45, and five other well-studied low-mass spiral galaxies (NGC 1156, NGC 2403, NGC 5023, M 33, and the LMC) with predictions from cosmological simulations, and found that for the stellar-to-halo mass models considered, the observed satellite numbers tend to be on the lower end of the expected range. This could mean either that there is an overprediction of luminous subhalos in ΛCDM or that we are missing some of the satellite members due to observational biases.

scholarly journals Discovery of an Ultra-faint Stellar System near the Magellanic Clouds with the DECam Local Volume Exploration Survey

2021 ◽  
Vol 910 (1) ◽  
pp. 18
Author(s):  
W. Cerny ◽  
A. B. Pace ◽  
A. Drlica-Wagner ◽  
P. S. Ferguson ◽  
S. Mau ◽  
...  
Keyword(s):  
Stellar System ◽  
Magellanic Clouds ◽  
Local Volume ◽  
Volume Exploration
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