21,395 research outputs found
ROSAT Detection and High Precision Localization of X-ray Sources in the November 19, 1978 Gamma-Ray Burst Error Box
We report on observations of the 1978, November 19 Gamma-Ray Burst source,
performed with the ROSAT X-ray HRI experiment. Two sources were detected, one
of which is possibly variable. The latter source is identical to the source
discovered in 1981 by the EINSTEIN satellite, and recently detected by ASCA.
The precise localization of these sources is given, and our data are compared
with optical, radio and previous X-ray data.Comment: 10 pages with 2 figures, Accepted for publication in the
Astrophysical Journal (Letters), Latex, aastex macros neede
Operator analysis of -widths of TMDs
Transverse momentum dependent (TMD) parton distribution functions (PDFs),
TMDs for short, are defined as the Fourier transform of matrix elements of
nonlocal combinations of quark and gluon fields. The nonlocality is bridged by
gauge links, which for TMDs have characteristic paths (future or past
pointing), giving rise to a process dependence that breaks universality. It is
possible, however, to construct sets of universal TMDs of which in a given
process particular combinations are needed with calculable, process-dependent,
coefficients. This occurs for both T-odd and T-even TMDs, including also the
{\it unpolarized} quark and gluon TMDs. This extends the by now well-known
example of T-odd TMDs that appear with opposite sign in single-spin azimuthal
asymmetries in semi-inclusive deep inelastic scattering or in the Drell-Yan
process. In this paper we analyze the cases where TMDs enter multiplied by
products of two transverse momenta, which includes besides the -broadening
observable, also instances with rank two structures. To experimentally
demonstrate the process dependence of the latter cases requires measurements of
second harmonic azimuthal asymmetries, while the -broadening will require
measurements of processes beyond semi-inclusive deep inelastic scattering or
the Drell-Yan process. Furthermore, we propose specific quantities that will
allow for theoretical studies of the process dependence of TMDs using lattice
QCD calculations.Comment: 10 pages, no figures; expanded discussions, matches version accepted
by JHE
Phenomenological Issues in Supersymmetry with Non-holomorphic Soft Breaking
We present a through discussion of motivations for and phenomenological
issues in supersymmetric models with minimal matter content and non-holomorphic
soft-breaking terms. Using the unification of the gauge couplings and assuming
SUSY is broken with non-standard soft terms, we provide semi-analytic solutions
of the RGEs for low and high choices of tan\beta which can be used to study the
phenomenology in detail. We also present a generic form of RGIs in mSUGRA
framework which can be used to derive new relations in addition to those
existing in the literature. Our results are mostly presented with respect to
the conventional minimal supersymmetric model for ease of comparison.Comment: 34 page
The development of a resource-efficient photovoltaic system
This paper presents the measures taken in the demonstration of the photovoltaic case study developed within the European project ‘Towards zero waste in industrial networks’ (Zerowin), integrating the D4R (Design for recycling, repair, refurbishment and reuse) criteria at both system and industrial network level. The demonstration is divided into three phases. The first phase concerns the development of a D4R photovoltaic concept, the second phase focused on the development of a specific component of photovoltaic systems and the third phase was the demonstration of the D4R design in two complete photovoltaic systems (grid-connected and stand-alone). This paper includes a description of the installed photovoltaic systems, including a brief summary at component level of the lithium ion battery system and the D4R power conditioning system developed for the pilot installations. Additionally, industrial symbioses within the network associated with the photovoltaic systems and the production model for the network are described
Entanglement, Holography and Causal Diamonds
We argue that the degrees of freedom in a d-dimensional CFT can be
re-organized in an insightful way by studying observables on the moduli space
of causal diamonds (or equivalently, the space of pairs of timelike separated
points). This 2d-dimensional space naturally captures some of the fundamental
nonlocality and causal structure inherent in the entanglement of CFT states.
For any primary CFT operator, we construct an observable on this space, which
is defined by smearing the associated one-point function over causal diamonds.
Known examples of such quantities are the entanglement entropy of vacuum
excitations and its higher spin generalizations. We show that in holographic
CFTs, these observables are given by suitably defined integrals of dual bulk
fields over the corresponding Ryu-Takayanagi minimal surfaces. Furthermore, we
explain connections to the operator product expansion and the first law of
entanglement entropy from this unifying point of view. We demonstrate that for
small perturbations of the vacuum, our observables obey linear two-derivative
equations of motion on the space of causal diamonds. In two dimensions, the
latter is given by a product of two copies of a two-dimensional de Sitter
space. For a class of universal states, we show that the entanglement entropy
and its spin-three generalization obey nonlinear equations of motion with local
interactions on this moduli space, which can be identified with Liouville and
Toda equations, respectively. This suggests the possibility of extending the
definition of our new observables beyond the linear level more generally and in
such a way that they give rise to new dynamically interacting theories on the
moduli space of causal diamonds. Various challenges one has to face in order to
implement this idea are discussed.Comment: 84 pages, 12 figures; v2: expanded discussion on constraints in
section 7, matches published versio
Acting without being in control: Exploring volition in Parkinson's disease with impulsive compulsive behaviours.
BACKGROUND: Several aspects of volitional control of action may be relevant in the pathophysiology of impulsive-compulsive behaviours (ICB) in Parkinson's disease (PD). We aimed to explore multiple aspects of action control, assessing reward-related behaviour, inhibition (externally and internally triggered) and sense of agency in PD patients, with and without ICB compared to healthy subjects. METHODS: Nineteen PD patients with ICB (PD-ICB), 19 PD without ICB (PD-no-ICB) and 19 healthy controls (HC) underwent a battery of tests including: Intentional Binding task which measures sense of agency; Stop Signal Reaction Time (SSRT) measuring capacity for reactive inhibition; the Marble task, assessing intentional inhibition; Balloon Analog Risk Task for reward sensitivity. RESULTS: One-way ANOVA showed significant main effect of group for action binding (p = 0.004, F = 6.27). Post hoc analysis revealed that PD-ICB had significantly stronger action binding than HC (p = 0.004), and PD-no-ICB (p = 0.04). There was no difference between PD-no-ICB and HC. SSRT did not differ between PD groups, whereas a significant difference between PD-no-ICB and HC was detected (p = 0.01). No other differences were found among groups in the other tasks. CONCLUSIONS: PD patients with ICB have abnormal performance on a psychophysical task assessing sense of agency, which might be related to a deficit in action representation at cognitive/experiential level. Yet, they have no deficit on tasks evaluating externally and internally triggered inhibitory control, or in reward-based decision-making. We conclude that impaired sense of agency may be a factor contributing to ICB in PD patients
In-flight measurements of energetic radiation from lightning and thunderclouds
In the certification procedure aircraft builders carry out so-called icing
tests flights, where the zero degree Celsius altitude is deliberately sought
and crossed in or under thunderstorms. Airbus also used these flights to test
ILDAS, a system aimed to determine lightning severity and attachment points
during flight from high speed data on the electric and magnetic field at the
aircraft surface. We used this unique opportunity to enhance the ILDAS systems
with two x-ray detectors coupled to high speed data recorders in an attempt to
determine the x-rays produced by lightning in-situ, with synchronous
determination of the lightning current distribution and electric field at the
aircraft. Such data are of interest in a study of lightning physics. In
addition, the data may provide clues to the x-ray dose for personnel and
equipment during flights. The icing campaign ran in April 2014; in six flights
we collected data of 61 lightning strikes on an Airbus test aircraft. In this
communication we briefly describe ILDAS and present selected results on three
strikes, two aircraft initiated and one intercepted. Most of the x-rays have
been observed synchronous with initiating negative leader steps, and as bursts
immediately preceding the current of the recoil process. Those processes
include the return stroke. The bursts last one to four micro-second and attain
x-ray energies up to 10 MeV. Intensity and spectral distribution of the x-rays
and the association with the current distribution are discussed. ILDAS also
continuously records x-rays at low resolution in time and amplitude.Comment: 28 pages, 9 figure
Thermodynamics of Higher Spin Black Holes in AdS
We discuss the thermodynamics of recently constructed three-dimensional
higher spin black holes in SL(N,R)\times SL(N,R) Chern-Simons theory with
generalized asymptotically-anti-de Sitter boundary conditions. From a
holographic perspective, these bulk theories are dual to two-dimensional CFTs
with W_N symmetry algebras, and the black hole solutions are dual to thermal
states with higher spin chemical potentials and charges turned on. Because the
notion of horizon area is not gauge-invariant in the higher spin theory, the
traditional approaches to the computation of black hole entropy must be
reconsidered. One possibility, explored in the recent literature, involves
demanding the existence of a partition function in the CFT, and consistency
with the first law of thermodynamics. This approach is not free from
ambiguities, however, and in particular different definitions of energy result
in different expressions for the entropy. In the present work we show that
there are natural definitions of the thermodynamically conjugate variables that
follow from careful examination of the variational principle, and moreover
agree with those obtained via canonical methods. Building on this intuition, we
derive general expressions for the higher spin black hole entropy and free
energy which are written entirely in terms of the Chern-Simons connections, and
are valid for both static and rotating solutions. We compare our results to
other proposals in the literature, and provide a new and efficient way to
determine the generalization of the Cardy formula to a situation with higher
spin charges.Comment: 30 pages, PDFLaTeX; v2: typos corrected, explicit expressions for the
free energy adde
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