1,515 research outputs found
Computing automorphic forms on Shimura curves over fields with arbitrary class number
We extend methods of Greenberg and the author to compute in the cohomology of
a Shimura curve defined over a totally real field with arbitrary class number.
Via the Jacquet-Langlands correspondence, we thereby compute systems of Hecke
eigenvalues associated to Hilbert modular forms of arbitrary level over a
totally real field of odd degree. We conclude with two examples which
illustrate the effectiveness of our algorithms.Comment: 15 pages; final submission to ANTS I
Antimatter cosmic rays from dark matter annihilation: First results from an N-body experiment
[Abridged]. We take advantage of the galaxy-like 3D dark matter map extracted
from the HORIZON Project results to calculate the positron and antiproton
fluxes from dark matter annihilation, in a model-independent approach as well
as for dark matter particle benchmarks relevant at the LHC scale (from
supersymmetric and extra-dimensional theories). Such a study is dedicated to a
better estimate of the theoretical uncertainties affecting predictions, while
the PAMELA and GLAST satellites are currently taking data which will soon
provide better observational constraints. We discuss the predictions of the
antiproton and positron fluxes, and of the positron fraction as well, as
compared to the current data. We finally discuss the limits of the Nbody
framework in describing the dark matter halo of our Galaxy.Comment: 19 pages, 9 figures. Backgrounds included and additional comments and
figures on the positron fraction. Accepted for publication in PR
Halo Geometry and Dark Matter Annihilation Signal
We study the impact of the halo shape and geometry on the expected weakly
interacting massive particle (WIMP) dark matter annihilation signal from the
galactic center. As the halo profile in the innermost region is still poorly
constrained, we consider different density behaviors like flat cores, cusps and
spikes, as well as geometrical distortions. We show that asphericity has a
strong impact on the annihilation signal when the halo profile near the
galactic center is flat, but becomes gradually less significant for cuspy
profiles, and negligible in the presence of a central spike. However, the
astrophysical factor is strongly dependent on the WIMP mass and annihilation
cross-section in the latter case.Comment: 5 pages, 4 figures, PR
The SKA view of the Neutral Interstellar Medium in Galaxies
Two major questions in galaxy evolution are how star-formation on small
scales leads to global scaling laws and how galaxies acquire sufficient gas to
sustain their star formation rates. HI observations with high angular
resolution and with sensitivity to very low column densities are some of the
important observational ingredients that are currently still missing. Answers
to these questions are necessary for a correct interpretation of observations
of galaxy evolution in the high-redshift universe and will provide crucial
input for the sub-grid physics in hydrodynamical simulations of galaxy
evolutions. In this chapter we discuss the progress that will be made with the
SKA using targeted observations of nearby individual disk and dwarf galaxies.Comment: 22 pages, 4 figures, to appear as part of 'Neutral Hydrogen' in
Proceedings 'Advancing Astrophysics with the SKA (AASKA14)', PoS(AASKA14)12
Modeling the Gas Flow in the Bar of NGC 1365
We present new observations of the strongly-barred galaxy NGC 1365, including
new photometric images and Fabry-Perot spectroscopy, as well as a detailed
re-analysis of the neutral hydrogen observations from the VLA archive. We find
the galaxy to be at once remarkably bi-symmetric in its I-band light
distribution and strongly asymmetric in the distribution of dust and in the
kinematics of the gas in the bar region. The velocity field mapped in the
H-alpha line reveals bright HII regions with velocities that differ by 60 to 80
km/s from that of the surrounding gas, which may be due to remnants of
infalling material. We have attempted hydrodynamic simulations of the bar flow
to estimate the separate disk and halo masses, using two different dark matter
halo models and covering a wide range of mass-to-light ratios (Upsilon) and bar
pattern speeds (Omega_p). None of our models provides a compelling fit to the
data, but they seem most nearly consistent with a fast bar, corotation at sim
1.2r_B, and Upsilon_I simeq 2.0 +- 1.0, implying a massive, but not fully
maximal, disk. The fitted dark halos are unusually concentrated, a requirement
driven by the declining outer rotation curve.Comment: 43 pages, 15 figures, accepted to appear in Ap
From Skew-Cyclic Codes to Asymmetric Quantum Codes
We introduce an additive but not -linear map from
to and exhibit some of its interesting
structural properties. If is a linear -code, then is an
additive -code. If is an additive cyclic code then
is an additive quasi-cyclic code of index . Moreover, if is a module
-cyclic code, a recently introduced type of code which will be
explained below, then is equivalent to an additive cyclic code if is
odd and to an additive quasi-cyclic code of index if is even. Given any
-code , the code is self-orthogonal under the trace
Hermitian inner product. Since the mapping preserves nestedness, it can be
used as a tool in constructing additive asymmetric quantum codes.Comment: 16 pages, 3 tables, submitted to Advances in Mathematics of
Communication
Mechanism of action of PD-1 receptor/ligand targeted cancer immunotherapy
Immunotherapy targeting the Programmed Death (PD-1) receptor/ligand (L) "checkpoint" rapidly gains ground in the treatment of many cancer types. To increase treatment scope and efficacy, predictive biomarkers and rational selection of co-treatments are required. To meet these demands, we must understand PD-1 function in detail. We here outline recent insights into the regulation of the CD8(+) T cell response by PD-1. The prevailing view has been that blockade of PD-1/ligand (L) interaction "reinvigorates" cytotoxic T lymphocytes (CTL) that were rendered dysfunctional in the tumor microenvironment (TME). However, this review stresses that tumors continuously communicate with adjacent draining lymph nodes (LNs) and that the PD-1 checkpoint also operates during T cell priming. We clarify the role of the PD-(L)1 system at the T cell/DC interface, where it regulates T cell receptor (TCR) signaling and CD28 costimulation and thus controls activation of tumor-specific T cells. We also highlight the importance of CD4(+) T cell help during priming, which allows DCs to provide other costimulatory and cytokine signals required for optimal CTL differentiation and likely avoidance of a dysfunctional state. Therefore, we pose that PD-(L)1 blockade should exploit LN function and be combined with "help" signals to optimize CTL efficacy.Tumorimmunolog
On higher congruences between cusp forms and Eisenstein series
In this paper we present several finite families of congruences between cusp
forms and Eisenstein series of higher weights at powers of prime ideals. We
formulate a conjecture which describes properties of the prime ideals and their
relation to the weights. We check the validity of the conjecture on several
numerical examples.Comment: 20 page
New Observations of Extra-Disk Molecular Gas in Interacting Galaxy Systems, Including a Two-Component System in Stephan's Quintet
We present new CO (1 - 0) observations of eleven extragalactic tails and
bridges in nine interacting galaxy systems, almost doubling the number of such
features with sensitive CO measurements. Eight of these eleven features were
undetected in CO to very low CO/HI limits, with the most extreme case being the
NGC 7714/5 bridge. This bridge contains luminous H II regions and has a very
high HI column density (1.6 X 10^21 cm^-2 in the 55" CO beam), yet was
undetected in CO to rms T(R)* = 2.4 mK. The HI column density is higher than
standard H2 and CO self-shielding limits for solar-metallicity gas, suggesting
that the gas in this bridge is metal-poor and has an enhanced N(H2)/I(CO) ratio
compared to the Galactic value. Only one of the eleven features in our sample
was unambiguously detected in CO, a luminous HI-rich star formation region near
an optical tail in the compact group Stephan's Quintet. We detect CO at two
widely separated velocities in this feature, at ~6000 km/s and ~6700 km/s. Both
of these components have HI and H-alpha counterparts. These velocities
correspond to those of galaxies in the group, suggesting that this gas is
material that has been removed from two galaxies in the group. The
CO/HI/H-alpha ratios for both components are similar to global values for
spiral galaxies.Comment: 39 pages, Latex, 15 figures, Astronomical Journal, in pres
Supporting employees with chronic conditions to stay at work:perspectives of occupational health professionals and organizational representatives
Contains fulltext :
231735.pdf (publisher's version ) (Open Access)Background: Supporting employees with chronic conditions can prevent work-related problems and facilitate sustainable employment. Various stakeholders are involved in providing support to these employees. Understanding their current practices and experienced barriers is useful for the development of an organizational-level intervention to improve this support. The aim of this study was to explore the current practices of occupational physicians and organizational representatives, identifying both barriers to providing support and opportunities for improvement. Methods: Two focus groups with sixteen occupational physicians and seven semi-structured interviews with organizational representatives were held between January and June 2018. Data was analyzed using thematic content analysis. Results: Several barriers to offer support were identified, including barriers at the organizational level (negative organizational attitudes towards employees with chronic conditions), the employee level (employees' reluctance to collaborate with employers in dealing with work-related problems), and in the collaboration between occupational physicians and organizational representatives. In addition, barriers in occupational health care were described, e.g. occupational physicians' lack of visibility and a lack of utilization of occupational physicians' support. Opportunities to optimize support included a shared responsibility of all stakeholders involved, actively anchoring prevention of work-related problems in policy and practice and a more pronounced role of the health care sector in preventing work-related problems. Conclusions: Preventing work-related problems for employees with chronic conditions can be achieved by addressing the identified barriers to provide support. In addition, both occupational physicians and organizational representatives should initiate and secure preventive support at the organizational level and in occupational health care. These insights are helpful in developing an intervention aimed at supporting employees with chronic conditions to stay at work.13 p
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