pinecone/core-2020-05-10-deduplication huggingface dataset:
Dilated Convolutional Neural Networks for Cardiovascular MR Segmentation
  in Congenital Heart Disease

We propose an automatic method using dilated convolutional neural networks
(CNNs) for segmentation of the myocardium and blood pool in cardiovascular MR
(CMR) of patients with congenital heart disease (CHD).
  Ten training and ten test CMR scans cropped to an ROI around the heart were
provided in the MICCAI 2016 HVSMR challenge. A dilated CNN with a receptive
field of 131x131 voxels was trained for myocardium and blood pool segmentation
in axial, sagittal and coronal image slices. Performance was evaluated within
the HVSMR challenge.
  Automatic segmentation of the test scans resulted in Dice indices of
0.80$\pm$0.06 and 0.93$\pm$0.02, average distances to boundaries of
0.96$\pm$0.31 and 0.89$\pm$0.24 mm, and Hausdorff distances of 6.13$\pm$3.76
and 7.07$\pm$3.01 mm for the myocardium and blood pool, respectively.
Segmentation took 41.5$\pm$14.7 s per scan.
  In conclusion, dilated CNNs trained on a small set of CMR images of CHD
patients showing large anatomical variability provide accurate myocardium and
blood pool segmentations
A Direct Elliptic Solver Based on Hierarchically Low-rank Schur
  Complements

A parallel fast direct solver for rank-compressible block tridiagonal linear
systems is presented. Algorithmic synergies between Cyclic Reduction and
Hierarchical matrix arithmetic operations result in a solver with $O(N \log^2
N)$ arithmetic complexity and $O(N \log N)$ memory footprint. We provide a
baseline for performance and applicability by comparing with well known
implementations of the $\mathcal{H}$-LU factorization and algebraic multigrid
with a parallel implementation that leverages the concurrency features of the
method. Numerical experiments reveal that this method is comparable with other
fast direct solvers based on Hierarchical Matrices such as $\mathcal{H}$-LU and
that it can tackle problems where algebraic multigrid fails to converge
An Introduction to Gas Accretion onto Galaxies

Evidence for gas accretion onto galaxies can be found throughout the
universe. In this chapter, I summarize the direct and indirect signatures of
this process and discuss the primary sources. The evidence for gas accretion
includes the star formation rates and metallicities of galaxies, the evolution
of the cold gas content of the universe with time, numerous indirect indicators
for individual galaxies, and a few direct detections of inflow. The primary
sources of gas accretion are the intergalactic medium, satellite gas and
feedback material. There is support for each of these sources from observations
and simulations, but the methods with which the fuel ultimately settles in to
form stars remain murky.Comment: 14 pages, 5 figures, Invited review to appear in Gas Accretion onto
  Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e,
  to be published by Springe
Gas Accretion and Galactic Chemical Evolution: Theory and Observations

This chapter reviews how galactic inflows influence galaxy metallicity. The
goal is to discuss predictions from theoretical models, but particular emphasis
is placed on the insights that result from using models to interpret
observations. Even as the classical G-dwarf problem endures in the latest round
of observational confirmation, a rich and tantalizing new phenomenology of
relationships between $M_*$, $Z$, SFR, and gas fraction is emerging both in
observations and in theoretical models. A consensus interpretation is emerging
in which star-forming galaxies do most of their growing in a quiescent way that
balances gas inflows and gas processing, and metal dilution with enrichment.
Models that explicitly invoke this idea via equilibrium conditions can be used
to infer inflow rates from observations, while models that do not assume
equilibrium growth tend to recover it self-consistently. Mergers are an overall
subdominant mechanism for delivering fresh gas to galaxies, but they trigger
radial flows of previously-accreted gas that flatten radial gas-phase
metallicity gradients and temporarily suppress central metallicities. Radial
gradients are generically expected to be steep at early times and then
flattened by mergers and enriched inflows of recycled gas at late times.
However, further theoretical work is required in order to understand how to
interpret observations. Likewise, more observational work is needed in order to
understand how metallicity gradients evolve to high redshifts.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springer. 29 pages, 2 figure
Gas Accretion and Angular Momentum

In this chapter, we review the role of gas accretion to the acquisition of
angular momentum, both in galaxies and in their gaseous halos. We begin by
discussing angular momentum in dark matter halos, with a brief review of tidal
torque theory and the importance of mergers, followed by a discussion of the
canonical picture of galaxy formation within this framework, where halo gas is
presumed to shock-heat to the virial temperature of the halo, following the
same spin distribution as the dark matter halo before cooling to the center of
the halo to form a galaxy there. In the context of recent observational
evidence demonstrating the presence of high angular momentum gas in galaxy
halos, we review recent cosmological hydrodynamic simulations that have begun
to emphasize the role of "cold flow" accretion---anisotropic gas accretion
along cosmic filaments that does not shock-heat before sinking to the central
galaxy. We discuss the implications of these simulations, reviewing a number of
recent developments in the literature, and suggest a revision to the canonical
model as it relates to the expected angular momentum content of gaseous halos
around galaxies.Comment: 22 pages, 3 figures. Invited review to appear in Gas Accretion onto
  Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e,
  to be published by Springe
Observational Diagnostics of Gas Flows: Insights from Cosmological
  Simulations

Galactic accretion interacts in complex ways with gaseous halos, including
galactic winds. As a result, observational diagnostics typically probe a range
of intertwined physical phenomena. Because of this complexity, cosmological
hydrodynamic simulations have played a key role in developing observational
diagnostics of galactic accretion. In this chapter, we review the status of
different observational diagnostics of circumgalactic gas flows, in both
absorption (galaxy pair and down-the-barrel observations in neutral hydrogen
and metals; kinematic and azimuthal angle diagnostics; the cosmological column
density distribution; and metallicity) and emission (Lya; UV metal lines; and
diffuse X-rays). We conclude that there is no simple and robust way to identify
galactic accretion in individual measurements. Rather, progress in testing
galactic accretion models is likely to come from systematic, statistical
comparisons of simulation predictions with observations. We discuss specific
areas where progress is likely to be particularly fruitful over the next few
years.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dave, to be published by
  Springer. Typos correcte
The Effect of Galactic Feedback on Gas Accretion and Wind Recycling

In the absence of galactic winds, the rate at which gas accretes onto
galaxies is determined by the gravitational potential and by radiative cooling.
However, outflows driven by supernovae and active galactic nuclei not only
eject gas from galaxies, but also prevent gas from accreting in the first
place. Furthermore, gas previously ejected from a galaxy can re-accrete onto
(the same or a different) galaxy. Because this gas has a high metallicity, its
cooling rate is relatively high, which will increase its chances to re-accrete.
This complex interplay between gas inflows and outflows is discussed in this
chapter. Wind recycling is found to be an important process that fuels galaxies
at late times and the recycled gas has different properties than gas accreting
for the first time. Quantitative conclusions, however, vary between studies,
because the amount of wind recycling is dependent on the details of the
feedback model. We discuss these differences, known caveats, and ways to make
progress in understanding how galaxies are fed at low redshift.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springe
Gas Accretion via Condensation and Fountains

For most of their lives, galaxies are surrounded by large and massive coronae
of hot gas, which constitute vast reservoirs for gas accretion. This Chapter
describes a mechanism that allows star-forming disc galaxies to extract gas
from their coronae. Stellar feedback powers a continuous circulation (galactic
fountain) of gas from the disc into the halo, producing mixing between
metal-rich disc material and metal-poor coronal gas. This mixing causes a
dramatic reduction of the cooling time of the corona making it condense and
accrete onto the disc. This fountain- driven accretion model makes clear
predictions for the kinematics of the extraplanar cold/warm gas in disc
galaxies, which are in good agreement with a number of independent
observations. The amount of gas accretion predicted by the model is of the
order of what is needed to sustain star formation. Accretion is expected to
occur preferentially in the outer parts of discs and its efficiency drops for
higher coronal temperatures. Thus galaxies are able to gather new gas as long
as they do not become too massive nor fall into large halos and maintain their
star-forming gaseous discs.Comment: 30 pages, 13 figures; invited review to appear in Gas Accretion onto
  Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e,
  to be published by Springe
Gas Accretion and Star-Formation Rates with IFUs and Background Quasars

Star-forming galaxies (SFGs) are forming stars at a regular pace, forming the
so-called main sequence (MS). However, all studies of their gas content show
that their gas reservoir ought to be depleted in 0.5-2 Gyr. Thus, SFGs are
thought to be fed by the continuous accretion of intergalactic gas in order to
sustain their star-formation activity. However, direct observational evidence
for this accretion phenomenon has been elusive. Theoretically, the accreted gas
coming from the intergalactic medium is expected to orbit about the halo,
delivering not just fuel for star-formation but also angular momentum to the
galaxy. This accreting material is thus expected to form a gaseous structure
that should be co-rotating with the host once at $r<0.3\;R_{\rm vir}$ or
$r<10-30$ kpc. Because of the rough alignment between the star-forming disk and
this extended gaseous structure, the accreting material can be most easily
detected with the combination of background quasars and integral field units
(IFUs). In this chapter, accretion studies using this technique are reviewed.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, in press (version
  matching proofs
Gas Accretion onto the Milky Way

The Milky Way is surrounded by large amounts of gaseous matter that are
slowly being accreted over cosmic timescales to support star formation in the
disk. The corresponding gas-accretion rate represents a key parameter for the
past, present, and future evolution of the Milky Way. In this article, I
discuss our current understanding of gas accretion processes in the Galaxy by
reviewing past and recent observational and theoretical studies. The first part
of this review deals with the spatial distribution of the different gas phases
in the Milky Way halo, the origin of the gas, and its total mass. The second
part discusses the gas dynamics and the physical processes that regulate the
gas flow from the outer Galactic halo to the disk. From the most recent studies
follows that the present-day gas accretion rate of the Milky Way is a few solar
masses per year, which is sufficient to maintain the Galaxy's star-formation
rate at its current level.Comment: 33 pages, 7 figures; invited review to appear in Gas Accretion onto
  Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dave,
  to be published by Springe
Neutral Gas Accretion onto Nearby Galaxies

While there is no lack of evidence for the accretion of stellar systems onto
nearby galaxies, direct evidence for the accretion of gas without stars is
scarce. Here we consider an inventory of starless gas "clouds" in and around
galaxies of the Local Group to discern their general properties and see how
they might appear in distant systems. The conclusion is that accreting gas
without stars is detected almost entirely within the circumgalactic medium of
large galaxies and is rare otherwise. If our Local Group is any example, the
best place to detect starless gas clouds is relatively close to galaxies.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springe
Gas Accretion and Star Formation Rates

Cosmological numerical simulations of galaxy evolution show that accretion of
metal-poor gas from the cosmic web drives the star formation in galaxy disks.
Unfortunately, the observational support for this theoretical prediction is
still indirect, and modeling and analysis are required to identify hints as
actual signs of star-formation feeding from metal-poor gas accretion. Thus, a
meticulous interpretation of the observations is crucial, and this
observational review begins with a simple theoretical description of the
physical process and the key ingredients it involves, including the properties
of the accreted gas and of the star-formation that it induces. A number of
observations pointing out the connection between metal-poor gas accretion and
star-formation are analyzed, specifically, the short gas consumption time-scale
compared to the age of the stellar populations, the fundamental metallicity
relationship, the relationship between disk morphology and gas metallicity, the
existence of metallicity drops in starbursts of star-forming galaxies, the
so-called G dwarf problem, the existence of a minimum metallicity for the
star-forming gas in the local universe, the origin of the alpha-enhanced gas
forming stars in the local universe, the metallicity of the quiescent BCDs, and
the direct measurements of gas accretion onto galaxies. A final section
discusses intrinsic difficulties to obtain direct observational evidence, and
points out alternative observational pathways to further consolidate the
current ideas.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springe
Gas Accretion Traced in Absorption in Galaxy Spectroscopy

The positive velocity shift of absorption transitions tracing diffuse
material observed in a galaxy spectrum is an unambiguous signature of gas flow
toward the host system. Spectroscopy probing, e.g., NaI D resonance lines in
the rest-frame optical or MgII and FeII in the near-ultraviolet is in principle
sensitive to the infall of cool material at temperatures ~ 100-10,000 K
anywhere along the line of sight to a galaxy's stellar component. However,
secure detections of this redshifted absorption signature have proved
challenging to obtain due to the ubiquity of cool gas outflows giving rise to
blueshifted absorption along the same sightlines. In this chapter, we review
the bona fide detections of this phenomenon. Analysis of NaI D line profiles
has revealed numerous instances of redshifted absorption observed toward
early-type and/or AGN-host galaxies, while spectroscopy of MgII and FeII has
provided evidence for ongoing gas accretion onto >5% of luminous, star-forming
galaxies at z ~ 0.5-1. We then discuss the potentially ground-breaking benefits
of future efforts to improve the spectral resolution of such studies, and to
leverage spatially-resolved spectroscopy for new constraints on inflowing gas
morphology.Comment: 21 pages, 7 figures. Invited review to appear in Gas Accretion onto
  Galaxies, Astrophysics and Space Science Library, eds. A. J. Fox & R. Dav\'e,
  to be published by Springe
Gas Accretion via Lyman Limit Systems

In cosmological simulations, a large fraction of the partial Lyman limit
systems (pLLSs; 16<log N(HI)<17.2) and LLSs (17.2log N(HI)<19) probes
large-scale flows in and out of galaxies through their circumgalactic medium
(CGM). The overall low metallicity of the cold gaseous streams feeding galaxies
seen in these simulations is the key to differentiating them from metal rich
gas that is either outflowing or being recycled. In recent years, several
groups have empirically determined an entirely new wealth of information on the
pLLSs and LLSs over a wide range of redshifts. A major focus of the recent
research has been to empirically determine the metallicity distribution of the
gas probed by pLLSs and LLSs in sizable and representative samples at both low
(z<1) and high (z>2) redshifts. Here I discuss unambiguous evidence for
metal-poor gas at all z probed by the pLLSs and LLSs. At z<1, all the pLLSs and
LLSs so far studied are located in the CGM of galaxies with projected distances
<100-200 kpc. Regardless of the exact origin of the low-metallicity pLLSs/LLSs,
there is a significant mass of cool, dense, low-metallicity gas in the CGM that
may be available as fuel for continuing star formation in galaxies over cosmic
time. As such, the metal-poor pLLSs and LLSs are currently among the best
observational evidence of cold, metal-poor gas accretion onto galaxies.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springe
Gas Accretion in Star-Forming Galaxies

Cold-mode gas accretion onto galaxies is a direct prediction of LCDM
simulations and provides galaxies with fuel that allows them to continue to
form stars over the lifetime of the Universe. Given its dramatic influence on a
galaxy's gas reservoir, gas accretion has to be largely responsible for how
galaxies form and evolve. Therefore, given the importance of gas accretion, it
is necessary to observe and quantify how these gas flows affect galaxy
evolution. However, observational data have yet to conclusively show that gas
accretion ubiquitously occurs at any epoch. Directly detecting gas accretion is
a challenging endeavor and we now have obtained a significant amount of
observational evidence to support it. This chapter reviews the current
observational evidence of gas accretion onto star-forming galaxies.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dav\'e, to be published by
  Springer. This chapter includes 22 pages with 7 Figure
The Circumgalactic Medium in Massive Halos

This chapter presents a review of the current state of knowledge on the cool
(T ~ 1e4 K) halo gas content around massive galaxies at z ~ 0.2-2. Over the
last decade, significant progress has been made in characterizing the cool
circumgalactic gas in massive halos of Mh ~ 1e12-1e14 Msun at intermediate
redshifts using absorption spectroscopy. Systematic studies of halo gas around
massive galaxies beyond the nearby universe are made possible by large
spectroscopic samples of galaxies and quasars in public archives. In addition
to accurate and precise constraints for the incidence of cool gas in massive
halos, detailed characterizations of gas kinematics and chemical compositions
around massive quiescent galaxies at z ~ 0.5 have also been obtained. Combining
all available measurements shows that infalling clouds from external sources
are likely the primary source of cool gas detected at d >~ 100 kpc from massive
quiescent galaxies. The origin of the gas closer in is currently less certain,
but SNe Ia driven winds appear to contribute significantly to cool gas found at
d < 100 kpc. In contrast, cool gas observed at d <~ 200 kpc from luminous
quasars appears to be intimately connected to quasar activities on parsec
scales. The observed strong correlation between cool gas covering fraction in
quasar host halos and quasar bolometric luminosity remains a puzzle. Combining
absorption-line studies with spatially-resolved emission measurements of both
gas and galaxies is the necessary next step to address remaining questions.Comment: 29 pages, 7 figures, invited review to appear in "Gas Accretion onto
  Galaxies", Astrophysics and Space Science Library, eds. A. Fox & R. Dave, to
  be published by Springe
Gas Accretion and Giant Lyman-alpha Nebulae

Several decades of observations and discoveries have shown that high-redshift
AGN and massive galaxies are often surrounded by giant Lyman-alpha nebulae
extending in some cases up to 500 kpc in size. In this review, I discuss the
properties of the such nebulae discovered at z>2 and their connection with gas
flows in and around the galaxies and their halos. In particular, I show how
current observations are used to constrain the physical properties and origin
of the emitting gas in terms of the Lyman-alpha photon production processes and
kinematical signatures. These studies suggest that recombination radiation is
the most viable scenario to explain the observed Lyman-alpha luminosities and
Surface Brightness for the large majority of the nebulae and imply that a
significant amount of dense, ionized and cold clumps should be present within
and around the halos of massive galaxies. Spectroscopic studies suggest that,
among the giant Lyman-alpha nebulae, the one associated with radio-loud AGN
should have kinematics dominated by strong, ionized outflows within at least
the inner 30-50 kpc. Radio-quiet nebulae instead present more quiescent
kinematics compatible with stationary situation and, in some cases, suggestive
of rotating structures. However, definitive evidences for accretion onto
galaxies of the gas associated with the giant Lyman-alpha emission are not
unambiguously detected yet. Deep surveys currently ongoing using other bright,
non-resonant lines such as Hydrogen H-alpha and HeII1640 will be crucial to
search for clearer signatures of cosmological gas accretion onto galaxies and
AGN.Comment: Invited review to appear in Gas Accretion onto Galaxies, Astrophysics
  and Space Science Library, eds. A. J. Fox & R. Dave', to be published by
  Springe
Mood-based On-Car Music Recommendations

Driving and music listening are two inseparable everyday activities for millions of people today in the world. Considering the high correlation between music, mood and driving comfort and safety, it makes sense to use appropriate and intelligent music recommendations based on the mood of drivers and songs in the context of car driving. The objective of this paper is to present the project of a contextual mood-based music recommender system capable of regulating the driver's mood and trying to have a positive influence on her driving behaviour. Here we present the proof of concept of the system and describe the techniques and technologies that are part of it. Further possible future improvements on each of the building blocks are also presented