242 research outputs found
Flouting the Elmo Necessity and Denying the Local Roots of Interpretation: Anthropology\u27s Quarrel with ACTA and Authoritarian IP Regimes
This paper uses an anthropological definition of culture to examine the intensification of intellectual property policing, coupled with an expansion of its definition. These are ACTA’s aims. I argue that acts of sharing lie at the root of communication; humans must share in order to learn. Furthermore, symbols change their meaning as they circulate in different cultural contexts. Therefore, in denying the fundamental importance of sharing and local interpretation, ACTA will not only fail spectacularly as a policy document. It will also fuel a “war” on file-sharers, users of generic medicines, and manufacturers, sellers, and buyers of imitative goods and services – in sum, a large portion of the world’s population. This avoidable war will be costly, and it will be detrimental to public interests and global health
A Search for Gravitational Waves from Binary Mergers with a Single Observatory
We present a search for merging compact binary gravitational-wave sources
that produce a signal appearing solely or primarily in a single detector. Past
analyses have heavily relied on coincidence between multiple detectors to
reduce non-astrophysical background. However, for of the total time
of the 2015-2017 LIGO-Virgo observing runs only a single detector was
operating. We discuss the difficulties in assigning significance and
calculating the probability of astrophysical origin for candidates observed
primarily by a single detector, and suggest a straightforward resolution using
a noise model designed to provide a conservative assessment given the observed
data. We also describe a procedure to assess candidates observed in a single
detector when multiple detectors are observing. We apply these methods to
search for binary black hole (BBH) and binary neutron star (BNS) mergers in the
open LIGO data spanning 2015-2017. The most promising candidate from our search
is 170817+03:02:46UTC (probability of astrophysical origin ): if astrophysical, this is consistent with a BBH merger with primary mass
, suggestive of a hierarchical merger origin. We
also apply our method to the analysis of GW190425 and find , though this value is highly dependent on assumptions about the noise and
signal models.Comment: 11 pages, 5 figures, 2 tables. Updated to match ApJ version.
Supplementary materials at https://github.com/gwastro/single-searc
Serum MicroRNA-21 as a Biomarker for Allergic Inflammatory Disease in Children
MicroRNAs (miRs) have emerged as useful biomarkers for different disease states, including allergic inflammatory diseases such as asthma and eosinophilic esophagitis (EoE). Serum miRs are a possible non-invasive method for diagnosis of such diseases. We focused on microRNA-21 (miR-21) levels in serum, in order to assess the feasibility of using this gene as a non-invasive biomarker for these diseases in the clinic, as well as to better understand the expression pattern of miR-21 in allergic inflammation. We used quantitative PCR (QPCR) to assay miR-21 and other control miRs in esophageal biopsies from EoE patients and serum samples from EoE and asthma patients. Serum levels of miR-21 were significantly elevated in patients with asthma, whereas serum miR-21 levels were not associated with the presence of allergen-specific IgE (i.e. atopy). Esophageal biopsies showed a large elevation of miR-21 in EoE and an increase in miR-21 in EoE serum. Control U6 miR did not vary between asthma and control patients, however EoE serum had significantly decreased U6 microRNA compared to controls. The decreased U6 in EoE sera did not completely account for the relative increase in miR-21 in the sera of EoE patients. We report for the first time that miR-21 is elevated in the sera of both asthma and EoE patients. We find no relation between serum miR-21 levels and atopy. Our results thus suggest miR-21 is a novel biomarker for human allergic inflammatory diseases
The PyCBC search for gravitational waves from compact binary coalescence
We describe the PyCBC search for gravitational waves from compact-object
binary coalescences in advanced gravitational-wave detector data. The search
was used in the first Advanced LIGO observing run and unambiguously identified
two black hole binary mergers, GW150914 and GW151226. At its core, the PyCBC
search performs a matched-filter search for binary merger signals using a bank
of gravitational-wave template waveforms. We provide a complete description of
the search pipeline including the steps used to mitigate the effects of noise
transients in the data, identify candidate events and measure their statistical
significance. The analysis is able to measure false-alarm rates as low as one
per million years, required for confident detection of signals. Using data from
initial LIGO's sixth science run, we show that the new analysis reduces the
background noise in the search, giving a 30% increase in sensitive volume for
binary neutron star systems over previous searches.Comment: 29 pages, 7 figures, accepted by Classical and Quantum Gravit
The clumpy structure of Eridani's debris disc revisited by ALMA
Eridani is the closest star to our Sun known to host a debris
disc. Prior observations in the (sub-)millimetre regime have potentially
detected clumpy structure in the disc and attributed this to interactions with
an (as yet) undetected planet. However, the prior observations were unable to
distinguish between structure in the disc and background confusion. Here we
present the first ALMA image of the entire disc, which has a resolution of
1.6"1.2". We clearly detect the star, the main belt and two point
sources. The resolution and sensitivity of this data allow us to clearly
distinguish background galaxies (that show up as point sources) from the disc
emission. We show that the two point sources are consistent with background
galaxies. After taking account of these, we find that resolved residuals are
still present in the main belt, including two clumps with a
significance -- one to the east of the star and the other to the northwest. We
perform -body simulations to demonstrate that a migrating planet can form
structures similar to those observed by trapping planetesimals in resonances.
We find that the observed features can be reproduced by a migrating planet
trapping planetesimals in the 2:1 mean motion resonance and the symmetry of the
most prominent clumps means that the planet should have a position angle of
either or . Observations over multiple epochs
are necessary to test whether the observed features rotate around the star.Comment: 16 pages, 10 figures, accepted for publication in MNRA
GASPS observations of Herbig Ae/Be stars with PACS/Herschel. The atomic and molecular content of their protoplanetary discs
We observed a sample of 20 representative Herbig Ae/Be stars and five A-type
debris discs with PACS onboard of Herschel. The observations were done in
spectroscopic mode, and cover far-IR lines of [OI], [CII], CO, CH+, H2O and OH.
We have a [OI]63 micron detection rate of 100% for the Herbig Ae/Be and 0% for
the debris discs. [OI]145 micron is only detected in 25%, CO J=18-17 in 45%
(and less for higher J transitions) of the Herbig Ae/Be stars and for [CII] 157
micron, we often found spatially variable background contamination. We show the
first detection of water in a Herbig Ae disc, HD 163296, which has a settled
disc. Hydroxyl is detected as well in this disc. CH+, first seen in HD 100546,
is now detected for the second time in a Herbig Ae star, HD 97048. We report
fluxes for each line and use the observations as line diagnostics of the gas
properties. Furthermore, we look for correlations between the strength of the
emission lines and stellar or disc parameters, such as stellar luminosity, UV
and X-ray flux, accretion rate, PAH band strength, and flaring. We find that
the stellar UV flux is the dominant excitation mechanism of [OI]63 micron, with
the highest line fluxes found in those objects with a large amount of flaring
and greatest PAH strength. Neither the amount of accretion nor the X-ray
luminosity has an influence on the line strength. We find correlations between
the line flux of [OI]63 micron and [OI]145 micron, CO J = 18-17 and [OI]6300
\AA, and between the continuum flux at 63 micron and at 1.3 mm, while we find
weak correlations between the line flux of [OI]63 micron and the PAH
luminosity, the line flux of CO J = 3-2, the continuum flux at 63 micron, the
stellar effective temperature and the Brgamma luminosity. (Abbreviated version)Comment: 20 pages, 29 figures, accepted by Astronomy and Astrophysic
POISSON project - II - A multi-wavelength spectroscopic and photometric survey of young protostars in L 1641
Characterising stellar and circumstellar properties of embedded young stellar
objects (YSOs) is mandatory for understanding the early stages of the stellar
evolution. This task requires the combination of both spectroscopy and
photometry, covering the widest possible wavelength range, to disentangle the
various protostellar components and activities. As part of the POISSON project,
we present a multi-wavelength spectroscopic and photometric investigation of
embedded YSOs in L1641, aimed to derive the stellar parameters and evolutionary
stages and to infer their accretion properties. Our database includes
low-resolution optical-IR spectra from the NTT and Spitzer (0.6-40 um) and
photometric data covering a spectral range from 0.4 to 1100 um, which allow us
to construct the YSOs spectral energy distributions (SEDs) and to infer the
main stellar parameters. The SED analysis allows us to group our 27 YSOs into
nine Class I, eleven Flat, and seven Class II objects. However, on the basis of
the derived stellar properties, only six Class I YSOs have an age of ~10^5 yr,
while the others are older 5x10^5-10^6 yr), and, among the Flat sources, three
out of eleven are more evolved objects (5x10^6-10^7 yr), indicating that
geometrical effects can significantly modify the SED shapes. Inferred mass
accretion rates (Macc) show a wide range of values (3.6x10^-9 to 1.2x10^-5
M_sun yr^-1), which reflects the age spread observed in our sample. Average
values of mass accretion rates, extinction, and spectral indices decrease with
the YSO class. The youngest YSOs have the highest Macc, whereas the oldest YSOs
do not show any detectable jet activity in either images and spectra. We also
observe a clear correlation among the YSO Macc, M*, and age, consistent with
mass accretion evolution in viscous disc models.Comment: 61 pages, 16 figures; A&A in pres
Space-based research in fundamental physics and quantum technologies
Space-based experiments today can uniquely address important questions
related to the fundamental laws of Nature. In particular, high-accuracy physics
experiments in space can test relativistic gravity and probe the physics beyond
the Standard Model; they can perform direct detection of gravitational waves
and are naturally suited for precision investigations in cosmology and
astroparticle physics. In addition, atomic physics has recently shown
substantial progress in the development of optical clocks and atom
interferometers. If placed in space, these instruments could turn into powerful
high-resolution quantum sensors greatly benefiting fundamental physics.
We discuss the current status of space-based research in fundamental physics,
its discovery potential, and its importance for modern science. We offer a set
of recommendations to be considered by the upcoming National Academy of
Sciences' Decadal Survey in Astronomy and Astrophysics. In our opinion, the
Decadal Survey should include space-based research in fundamental physics as
one of its focus areas. We recommend establishing an Astronomy and Astrophysics
Advisory Committee's interagency ``Fundamental Physics Task Force'' to assess
the status of both ground- and space-based efforts in the field, to identify
the most important objectives, and to suggest the best ways to organize the
work of several federal agencies involved. We also recommend establishing a new
NASA-led interagency program in fundamental physics that will consolidate new
technologies, prepare key instruments for future space missions, and build a
strong scientific and engineering community. Our goal is to expand NASA's
science objectives in space by including ``laboratory research in fundamental
physics'' as an element in agency's ongoing space research efforts.Comment: a white paper, revtex, 27 pages, updated bibliograph
Star Formation and Dynamics in the Galactic Centre
The centre of our Galaxy is one of the most studied and yet enigmatic places
in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre
(GC) is the ideal environment to study the extreme processes that take place in
the vicinity of a supermassive black hole (SMBH). Despite the hostile
environment, several tens of early-type stars populate the central parsec of
our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and
inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the
SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The
formation of such early-type stars has been a puzzle for a long time: molecular
clouds should be tidally disrupted by the SMBH before they can fragment into
stars. We review the main scenarios proposed to explain the formation and the
dynamical evolution of the early-type stars in the GC. In particular, we
discuss the most popular in situ scenarios (accretion disc fragmentation and
molecular cloud disruption) and migration scenarios (star cluster inspiral and
Hills mechanism). We focus on the most pressing challenges that must be faced
to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in
expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A.,
'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201
Circumstellar discs: What will be next?
This prospective chapter gives our view on the evolution of the study of
circumstellar discs within the next 20 years from both observational and
theoretical sides. We first present the expected improvements in our knowledge
of protoplanetary discs as for their masses, sizes, chemistry, the presence of
planets as well as the evolutionary processes shaping these discs. We then
explore the older debris disc stage and explain what will be learnt concerning
their birth, the intrinsic links between these discs and planets, the hot dust
and the gas detected around main sequence stars as well as discs around white
dwarfs.Comment: invited review; comments welcome (32 pages
- …