11,972 research outputs found
Radio Continuum Sources Associated with AB Aur
We present high angular resolution, high-sensitivity Very Large Array
observations at 3.6 cm of the Herbig Ae star AB Aur. This star is of interest
since its circumstellar disk exhibits characteristics that have been attributed
to the presence of an undetected low mass companion or giant gas planet. Our
image confirms the continuum emission known to exist in association with the
star, and detects a faint protuberance that extends about to its
SE. Previous theoretical considerations and observational results are
consistent with the presence of a companion to AB Aur with the separation and
position angle derived from our radio data. We also determine the proper motion
of AB Aur by comparing our new observations with data taken about 17 years ago
and find values consistent with those found by Hipparcos.Comment: 6 pages, 1 figur
Revisiting instanton corrections to the Konishi multiplet
We revisit the calculation of instanton effects in correlation functions in
SYM involving the Konishi operator and operators of twist two.
Previous studies revealed that the scaling dimensions and the OPE coefficients
of these operators do not receive instanton corrections in the semiclassical
approximation. We go beyond this approximation and demonstrate that, while
operators belonging to the same supermultiplet ought to have the
same conformal data, the evaluation of quantum instanton corrections for one
operator can be mapped into a semiclassical computation for another operator in
the same supermultiplet. This observation allows us to compute explicitly the
leading instanton correction to the scaling dimension of operators in the
Konishi supermultiplet as well as to their structure constants in the OPE of
two half-BPS scalar operators. We then use these results, together with
crossing symmetry, to determine instanton corrections to scaling dimensions of
twist-four operators with large spin.Comment: 25 pages; v2: minor changes, typos correcte
Classification of Triadic Chord Inversions Using Kohonen Self-organizing Maps
In this paper we discuss the application of the Kohonen Selforganizing
Maps to the classification of triadic chords in inversions and root
positions. Our motivation started in the validation of SchönbergŽs hypotheses of
the harmonic features of each chord inversion. We employed the Kohonen
network, which has been generally known as an optimum pattern classification
tool in several areas, including music, to verify that hypothesis. The outcomes
of our experiment refuse the SchönbergŽs assumption in two aspects: structural
and perceptual/functional
The generic mapping tools version 6
The Generic Mapping Tools (GMT) software is ubiquitous in the Earth and ocean sciences. As a cross-platform tool producing high-quality maps and figures, it is used by tens of thousands of scientists around the world. The basic syntax of GMT scripts has evolved very slowly since the 1990s, despite the fact that GMT is generally perceived to have a steep learning curve with many pitfalls for beginners and experienced users alike. Reducing these pitfalls means changing the interface, which would break compatibility with thousands of existing scripts. With the latest GMT version 6, we solve this conundrum by introducing a new "modern mode" to complement the interface used in previous versions, which GMT 6 now calls "classic mode." GMT 6 defaults to classic mode and thus is a recommended upgrade for all GMT 5 users. Nonetheless, new users should take advantage of modern mode to make shorter scripts, quickly access commonly used global data sets, and take full advantage of the new tools to draw subplots, place insets, and create animations.Funding Agency
National Science Foundation (NSF)
Appeared in article as
U.S. National Science Foundation
MSU Geological Sciences Endowmentinfo:eu-repo/semantics/publishedVersio
Kinematics of the Outflow From The Young Star DG Tau B: Rotation in the vicinities of an optical jet
We present CO(2-1) line and 1300 m continuum observations made
with the Submillimeter Array (SMA) of the young star DG Tau B. We find, in the
continuum observations, emission arising from the circumstellar disk
surrounding DG Tau B. The CO(2-1) line observations, on the other hand,
revealed emission associated with the disk and the asymmetric outflow related
with this source. Velocity asymmetries about the flow axis are found over the
entire length of the flow. The amplitude of the velocity differences is of the
order of 1 -- 2 km s over distances of about 300 -- 400 AU. We interpret
them as a result of outflow rotation. The sense of the outflow and disk
rotation is the same. Infalling gas from a rotating molecular core cannot
explain the observed velocity gradient within the flow. Magneto-centrifugal
disk winds or photoevaporated disk winds can produce the observed rotational
speeds if they are ejected from a keplerian disk at radii of several tens of
AU. Nevertheless, these slow winds ejected from large radii are not very
massive, and cannot account for the observed linear momentum and angular
momentum rates of the molecular flow. Thus, the observed flow is probably
entrained material from the parent cloud. DG Tau B is a good laboratory to
model in detail the entrainment process and see if it can account for the
observed angular momentum.Comment: Accepted to Ap
Disease tolerance and immunity in host protection against infection
The deposited article is a pre-print version.This publication hasn't any creative commons license associated.This deposit is composed by the main article which contains attached the supplementary materials.The immune system probably evolved to limit the negative effects exerted by pathogens on host homeostasis. This defence strategy relies on the concerted action of innate and adaptive components of the immune system, which sense and target pathogens for containment, destruction or expulsion. Resistance to infection refers to these immune functions, which reduce the pathogen load of an infected host as the means to preserve homeostasis. Immune-driven resistance to infection is coupled to an additional, and arguably as important, defence strategy that limits the extent of dysfunction imposed on host parenchymal tissues during infection, without exerting a direct negative effect on pathogens. This defence strategy, known as disease tolerance, relies on tissue damage control mechanisms that prevent the deleterious effects of pathogens and that uncouples immune-driven resistance mechanisms from immunopathology and disease. In this Review, we provide a unifying view of resistance and disease tolerance in the framework of immunity to infection.Instituto Gulbenkian de CiĂȘncia; Fundação Calouste Gulbenkian; Fundação para a CiĂȘncia e Tecnologia grants: (PTDC/SAU-TOX/116627/2010, HMSP-ICT/0022/2010, PTDC/BEX-GMG/3128/2014); ERC grants: (ERC-2011-AdG 294709-DAMAGECONTROL, ERC-2014-CoG 647888-iPROTECTION).info:eu-repo/semantics/publishedVersio
A Population of Massive Globular Clusters in NGC 5128
We present velocity dispersion measurements of 14 globular clusters in NGC
5128 (Centarus A) obtained with the MIKE echelle spectrograph on the 6.5m
Magellan Clay telescope. These clusters are among the most luminous globular
clusters in NGC 5128 and have velocity dispersions comparable to the most
massive clusters known in the Local Group, ranging from 10 - 30 km/s. We
describe in detail our cross-correlation measurements, as well as simulations
to quantify the uncertainties. These 14 globular clusters are the brightest NGC
5128 globular clusters with surface photometry and structural parameters
measured from the Hubble Space Telescope. We have used these measurements to
derive masses and mass-to-light ratios for all of these clusters and establish
that the fundamental plane relations for globular clusters extend to an order
of magnitude higher mass than in the Local Group. The mean mass-to-light ratio
for the NGC 5128 clusters is ~3+/-1, higher than measurements for all but the
most massive Local Group clusters. These massive clusters begin to bridge the
mass gap between the most massive star clusters and the lowest-mass galaxies.
We find that the properties of NGC 5128 globular clusters overlap quite well
with the central properties of nucleated dwarf galaxies and ultracompact dwarf
galaxies. As six of these clusters also show evidence for extratidal light, we
hypothesize that at least some of these massive clusters are the nuclei of
tidally stripped dwarfs.Comment: ApJ Accepted, 15 pages, 9 figures, uses emulateapj.st
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