59 research outputs found
Collaborative Dynamic 3D Scene Graphs for Automated Driving
Maps have played an indispensable role in enabling safe and automated
driving. Although there have been many advances on different fronts ranging
from SLAM to semantics, building an actionable hierarchical semantic
representation of urban dynamic scenes from multiple agents is still a
challenging problem. In this work, we present Collaborative URBan Scene Graphs
(CURB-SG) that enable higher-order reasoning and efficient querying for many
functions of automated driving. CURB-SG leverages panoptic LiDAR data from
multiple agents to build large-scale maps using an effective graph-based
collaborative SLAM approach that detects inter-agent loop closures. To
semantically decompose the obtained 3D map, we build a lane graph from the
paths of ego agents and their panoptic observations of other vehicles. Based on
the connectivity of the lane graph, we segregate the environment into
intersecting and non-intersecting road areas. Subsequently, we construct a
multi-layered scene graph that includes lane information, the position of
static landmarks and their assignment to certain map sections, other vehicles
observed by the ego agents, and the pose graph from SLAM including 3D panoptic
point clouds. We extensively evaluate CURB-SG in urban scenarios using a
photorealistic simulator. We release our code at
http://curb.cs.uni-freiburg.de.Comment: Refined manuscript and extended supplementar
The Stellar and Gas Kinematics of the LITTLE THINGS Dwarf Irregular Galaxy NGC 1569
In order to understand the formation and evolution of dIm galaxies, one needs
to understand their three-dimensional structure. We present measurements of the
stellar velocity dispersion in NGC 1569, a nearby post-starburst dIm galaxy.
The stellar vertical velocity dispersion, , coupled with the
maximum rotational velocity derived from \ion{H}{1} observations, , gives a measure of how kinematically hot the galaxy is, and, therefore,
indicates its structure. We conclude that the stars in NGC 1569 are in a thick
disk with a = 2.4 0.7. In addition to the
structure, we analyze the ionized gas kinematics from \ion{O}{3} observations
along the morphological major axis. These data show evidence for outflow from
the inner starburst region and a potential expanding shell near supermassive
star cluster (SSC) A. When compared to the stellar kinematics, the velocity
dispersion of the stars increase in the region of SSC A supporting the
hypothesis of an expanding shell. The stellar kinematics closely follow the
motion of the gas. Analysis of high resolution \ion{H}{1} data clearly reveals
the presence of an \ion{H}{1} cloud that appears to be impacting the eastern
edge of NGC 1569. Also, an ultra-dense \ion{H}{1} cloud can be seen extending
to the west of the impacting \ion{H}{1} cloud. This dense cloud is likely the
remains of a dense \ion{H}{1} bridge that extended through what is now the
central starburst area. The impacting \ion{H}{1} cloud was the catalyst for the
starburst, thus turning the dense gas into stars over a short timescale,
1 Gyr. We performed a careful study of the spectral energy distribution using
infrared, optical, and ultraviolet photometry producing a state-of-the-art mass
model for the stellar disk. This mass modeling shows that stars dominate the
gravitational potential in the inner 1 kpc.Comment: 49 pages, 25 figures, accepted in A
Biofeedback eletromiogråfico e parùmetros da dinamometria isocinética de joelho e tornozelo de jogadores de futebol amador
Electromyography has been used to evaluate the voluntary control of muscular activity. One of the highlights among the techniques is electromyography biofeedback (EMGBio), which works as a facilitator of neuromotor development, including playing sports. Objective: To analyze the effect of EMGBio within the isokinetic parameters of knee flexion and extension and ankle inversion and eversion in amateur soccer players. Subjects: Two randomized groups of fourteen male amateur soccer players: Training group (TG) â seven athletes, with an age of 23 ± 2 (22 and 28) years old, body mass 75.7kg ± 4.0kg (72 and 80), height 182cm ± 4cm (176 and 188) and Control Group (CG) â seven athletes, with an age of 24 ± 2 (21 and 28) years old, body mass 72.3kg ± 9.4kg (59 and 79), height 175cm ± 5cm (169 and 180). Methods: all athletes were evaluated by a clinical protocol: anamnesis, occurrence of injuries and visual analogue scale of pain and were subjected to knee flexion and extension and ankle inversion and eversion isokinetic dynamometry. The training group had twelve sessions of EMGBio once a week. At the end of the sessions, all athletes were revaluated. Results: At a velocity of 30 deg/s, the ankle eversion peak torque of 0.18 seconds (PT of 0.18s) was higher in the training group and at a velocity of 60 deg/s, the knee flexion PT of 0.18s was higher in the training group. Conclusion: Electromyographic biofeedback improved the isokinetic parameters of the amateur soccer players.A eletromiografia tem sido utilizada para avaliar o con- trole voluntĂĄrio da atividade muscular. Dentre as tĂ©cnicas destaca-se o biofeedback eletromiogrĂĄfico como facilitador do aprendizado neuromotor, inclusive na prĂĄtica esportiva. Objetivo: Analisar o efeito do biofeedback eletromiogrĂĄfico nos parĂąmetros isocinĂ©ticos dos fle- xores e extensores do joelho e inversores e eversores do tornozelo em jogadores de futebol amador. CasuĂstica: 14 atletas de futebol amador do gĂȘnero masculino randomizados em dois grupos: Gru- po Treino (GT) - sete atletas, idade de 23 ± 2 (22 e 28) anos, massa corpĂłrea 75,7 ± 4,0(72 e 80) kg , estatura 182 ± 4 (176 e 188) cm e Grupo Controle (GC) - sete atletas com idade 24 ± 2 (21 e 28) anos, massa corpĂłrea 72,3± 9,4 (59 e 79) kg, estatura 175± 5 (169 e 180) cm. MĂ©todo: Todos os atletas foram avaliados por um protocolo clĂnico: anamnese, incidĂȘncia de lesĂ”es e escala visual anĂĄloga de dor e foram submetidos Ă dinamometria isocinĂ©tica dos inversores e eversores do tornozelo e flexores e extensores do joelho. O GT realizou 12 sessĂ”es de biofeedback eletromiogrĂĄfico, uma vez por semana. No final das sessĂ”es, todos os atletas foram reavaliados. Resultados: Na velocidade de 30Âș/ seg., o pico de torque 0,18 segundos (PT 0,18s) dos eversores do tornozelo foi maior no GT e no joelho, na velocidade de 60Âș/seg. o PT 0,18s dos flexores de joelho foram maiores no GT. ConclusĂŁo: O biofeedback eletromiogrĂĄfico melhorou os parĂąmetros isocinĂ©ticos dos jogadores de futebol amador
The MALATANG Survey : The L GAS-L IR Correlation on Sub-kiloparsec Scale in Six Nearby Star-forming Galaxies as Traced by HCN J = 4 â 3 and HCO + J = 4 â 3
This is an author-created, un-copyedited version of an article published in The Astrophysical Journal. The Version of Record is available online at https://doi.org/10.3847/1538-4357/aac512.We present HCN J = 4â3 and HCO+ J = 4â3 maps of six nearby star-forming galaxies, NGC 253, NGC 1068, IC 342, M82, M83, and NGC 6946, obtained with the James Clerk Maxwell Telescope as part of the MALATANG survey. All galaxies were mapped in the central 2Ă2 region at 14 (FWHM) resolution (corresponding to linear scales of âŒ0.2-1.0 kpc). The LIR-Ldense relation, where the dense gas is traced by the HCN J = 4â3 and the HCO+ J = 4â3 emission, measured in our sample of spatially resolved galaxies is found to follow the linear correlation established globally in galaxies within the scatter. We find that the luminosity ratio, LIR/Ldense, shows systematic variations with LIR within individual spatially resolved galaxies, whereas the galaxy-integrated ratios vary little. A rising trend is also found between LIR/Ldense ratio and the warm-dust temperature gauged by the 70 ÎŒm/100 ÎŒm flux ratio. We find that the luminosity ratios of IR/HCN (4-3) and IR/HCO+ (4-3), which can be taken as a proxy for the star formation efficiency (SFE) in the dense molecular gas (SFE dense), appear to be nearly independent of the dense gas fraction ( f dense) for our sample of galaxies. The SFE of the total molecular gas (SFEmol) is found to increase substantially with f dense when combining our data with those on local (ultra)luminous infrared galaxies and high-z quasars. The mean LHCN(4-3) LHCO+(4-3) line ratio measured for the six targeted galaxies is 0.9±0.6. No significant correlation is found for the L'HCN(4-3) L'HCO+(4-3) ratio with the star formation rate as traced by L IR, nor with the warm-dust temperature, for the different populations of galaxies.Peer reviewe
The MALATANG Survey : Dense Gas and Star Formation from High Transition HCN and HCO+ maps of NGC253
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society. © 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.To study the high-transition dense-gas tracers and their relationships to the star formation of the inner 2 kpc circumnuclear region of NGC253, we present HCN and HCO maps obtained with the James Clerk Maxwell Telescope (JCMT). With the spatially resolved data, we compute the concentration indices for the different tracers. HCN and HCO 4-3 emission features tend to be centrally concentrated, which is in contrast to the shallower distribution of CO 1-0 and the stellar component. The dense-gas fraction (, traced by the velocity-integrated-intensity ratios of HCN/CO and HCO/CO) and the ratio (CO 3-2/1-0) decline towards larger galactocentric distances, but increase with higher SFR surface density. The radial variation and the large scatter of and imply distinct physical conditions in different regions of the galactic disc. The relationships of versus , and SFE versus are explored. SFE increases with higher in this galaxy, which is inconsistent with previous work that used HCN 1-0 data. This implies that existing stellar components might have different effects on the high- HCN and HCO than their low- emission. We also find that SFE seems to be decreasing with higher , which is consistent with previous works, and it suggests that the ability of the dense gas to form stars diminishes when the average density of the gas increases. This is expected in a scenario where only the regions with high-density contrast collapse and form stars.Peer reviewe
A Spatially Resolved Radio Spectral Index Study of the Dwarf Irregular Galaxy NGC\,1569
© The Author(s) 2018. Published by Oxford University Press on behalf of The Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.We study the resolved radio continuum spectral energy distribution of the dwarf irregular galaxy, NGC 1569, on a beam-by-beam basis to isolate and study its spatially resolved radio emission characteristics. Utilizing high-quality NRAO Karl G. Jansky Very Large Array observations that densely sample the 1-34 GHz frequency range, we adopt a Bayesian fitting procedure, where we use Hα emission that has not been corrected for extinction as a prior, to produce maps of how the separated thermal emission, non-thermal emission, and non-thermal spectral index vary across NGC1569's main disc. We find a higher thermal fraction at 1 GHz than is found in spiral galaxies (26 -3 +2 per cent) and find an average non-thermal spectral index α =-0.53 ± 0.02, suggesting that a young population of cosmic ray electrons is responsible for the observed non-thermal emission. By comparing our recovered map of the thermal radio emission with literature Hα maps, we estimate the total reddening along the line of sight to NGC1569 to be E(B - V) = 0.49 ± 0.05, which is in good agreement with other literature measurements. Spatial variations in the reddening indicate that a significant portion of the total reddening is due to internal extinction within NGC1569.Peer reviewedFinal Published versio
Unveiling the Sigma-Discrepancy in IR-Luminous Mergers I: Dust & Dynamics
Mergers in the local universe present a unique opportunity for studying the
transformations of galaxies in detail. Presented here are recent results, based
on multi-wavelength, high-resolution imaging and medium resolution
spectroscopy, which demonstrate how star-formation and the presence of Red
Supergiants and/or Asymptotic Giant Branch stars has lead to a serious
underestimation of the dynamical masses of infrared-bright galaxies. The
dominance of a nuclear disk of young stars in the near-infrared bands, where
dust obscuration does not block their signatures, can severely bias the global
properties measured in a galaxy, including mass. This explains why past studies
of gas-rich Luminous & Ultraluminous Infrared Galaxies, which have measured
dynamical masses using the 1.62 or 2.29 micron CO band-heads, have found that
these galaxies are forming m < m* ellipticals. On the other hand, precisely
because of dust obscuration, I-band photometry and central velocity dispersions
obtained with the Calcium II triplet at 0.85 microns reflect the global
properties of the mergers and suggest that all types of merger remnants,
including infrared-bright ones, will form m > m* ellipticals. Moreover, merger
remnants, including LIRGs, are placed on the I-band Fundamental Plane for the
first time and appear to be virtually indistinguishable from elliptical
galaxies.Comment: Accepted for publication in The Astrophysical Journal, to appear Feb
20, 2010 v710. 82 pages, 19 Figures, 2 Appendices Minor update to reference
Measuring resting cerebral haemodynamics using MRI arterial spin labelling and transcranial Doppler ultrasound: comparison in younger and older adults
Introduction: Resting cerebral blood flow (CBF) and perfusion measures have been used to determine brain health. Studies showing variation in resting CBF with age and fitness level using different imaging approaches have produced mixed findings. We assess the degree to which resting CBF measures through transcranial Doppler (TCD) and arterial spin labelling (ASL) MRI provide complementary information in older and younger, fit and unfit cohorts. Methods: Thirty-five healthy volunteers (20 younger: 24±7y; 15 older: 66±7y) completed two experimental sessions (TCD/MRI). Aging and fitness effects within and between imaging modalities were assessed. Results: Middle cerebral artery blood velocity (MCAv, TCD) was lower and transit time (MRI) slower in older compared with younger participants (p < 0.05). The younger group had higher grey matter cerebral perfusion (MRI) than the older group, albeit not significantly (p=0.13). Surprisingly, fitness effects in the younger group (decrease/increase in MCAv/transit time with fitness, respectively) opposed the older group (increase/decrease in MCAv/transit time). Whole cohort transit times correlated with MCAv (r=-0.63; p < 0.05), whereas tissue perfusion did not correlate with TCD measures. Conclusion: TCD and MRI modalities provide complementary resting CBF measures, with similar effects across the whole cohort and between subgroups (age/fitness) if metrics are comparable (e.g., velocity [TCD] vs transit time [MRI])
Undesirable contamination of DNA electrophoresed through polyacrylamide and agarose gels as revealed by reversing-pulse electric birefringence signals
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