124 research outputs found
Saying Hello World with Epsilon - A Solution to the 2011 Instructive Case
Epsilon is an extensible platform of integrated and task-specific languages
for model management. With solutions to the 2011 TTC Hello World case, this
paper demonstrates some of the key features of the Epsilon Object Language (an
extension and reworking of OCL), which is at the core of Epsilon. In addition,
the paper introduces several of the task-specific languages provided by Epsilon
including the Epsilon Generation Language (for model-to-text transformation),
the Epsilon Validation Language (for model validation) and Epsilon Flock (for
model migration).Comment: In Proceedings TTC 2011, arXiv:1111.440
Particle dynamics in a class of 2-dimensional gravity theories
We provide a method to determine the motion of a classical massive particle
in a background geometry of 2-dimensional gravity theories, for which the
Birkhoff theorem holds. In particular, we get the particle trajectory in a
continuous class of 2-dimensional dilaton gravity theories that includes the
Callan-Giddings-Harvey-Strominger (CGHS) model, the Jackiw-Teitelboim (JT)
model, and the -dimensional -wave Einstein gravity. The explicit
trajectory expressions for these theories are given along with the discussions
on the results.Comment: 15 pages, LaTeX. The deletion of the repeated portion of the abstract
and the proper line wrapping of the tex file. No other change
Electromigration of Single-Layer Clusters
Single-layer atom or vacancy clusters in the presence of electromigration are
studied theoretically assuming an isotropic medium. A variety of distinctive
behaviors distinguish the response in the three standard limiting cases of
periphery diffusion (PD), terrace diffusion (TD), and evaporation-condensation
(EC). A general model provides power laws describing the size dependence of the
drift velocity in these limits, consistent with established results in the case
of PD. The validity of the widely used quasistatic limit is calculated. Atom
and vacancy clusters drift in opposite directions in the PD limit but in the
same direction otherwise. In absence of PD, linear stability analysis reveals a
new type of morphological instability, not leading to island break-down. For
strong electromigration, Monte Carlo simulations show that clusters then
destabilize into slits, in contrast to splitting in the PD limit.
Electromigration affects the diffusion coefficient of the cluster and
morphological fluctuations, the latter diverging at the instability threshold.
An instrinsic attachment-detachment bias displays the same scaling signature as
PD in the drift velocity.Comment: 11 pages, 4 figure
Many particle entanglement in two-component Bose-Einstein Condensates
We investigate schemes to dynamically create many particle entangled states
of a two component Bose-Einstein condensate in a very short time proportional
to 1/N where is the number of condensate particles. For small we
compare exact numerical calculations with analytical semiclassical estimates
and find very good agreement for . We also estimate the effect of
decoherence on our scheme, study possible scenarios for measuring the entangled
states, and investigate experimental imperfections.Comment: 12 pages, 8 figure
Low Energy Supersymmetry from Non-Geometry
We study a class of flux compactifications that have all the moduli
stabilised, a high (GUT) string scale and a low (TeV) gravitino mass that is
generated dynamically. These non-geometric compactifications correspond to type
II string theories on SU(3)xSU(3) structure orientifolds. The resulting
superpotentials admit, excluding non-perturbative effects, supersymmetric
Minkowski vacua with any number of moduli stabilised. We argue that
non-perturbative effects are present and introduce terms in the superpotential
that are exponentially suppressed by the same moduli that appear
perturbatively. These deform the supersymmetric Minkowski vacua to
supersymmetric AdS vacua with an exponentially small gravitino mass. The
resulting vacua allow for low scale supersymmetry breaking which can be
realised by a number of mechanisms.Comment: 36pp; v2 references added, minor clarifications, JHEP versio
Chiral 4d string vacua with D-branes and NSNS and RR fluxes
We discuss type IIB orientifolds with D-branes, and NSNS and RR field
strength fluxes. The D-brane sectors lead to open string spectra with
non-abelian gauge symmetry and charged chiral fermions. The closed string field
strengths generate a scalar potential stabilizing most moduli. We describe the
construction of N=1 supersymmetric models in the context of orientifolds of IIB
theory on T^6/Z_2 x Z_2, containing D9-branes with world-volume magnetic
fluxes, and illustrate model building possibilities with several explicit
examples. We comment on a T-dual picture with D8-branes on non-Calabi-Yau
half-flat geometries, and discuss some of the topological properties of such
configurations. We also explore the construction of models with fluxes and with
D3-branes at singularities and present a non-supersymmetric 3-family SU(5)
model.Comment: latex, 49 pages, 2 figure
Framing the concept of satellite remote sensing essential biodiversity variables: challenges and future directions
Although satellite-based variables have for long been expected to be key components to a unified and global biodiversity monitoring strategy, a definitive and agreed list of these variables still remains elusive. The growth of interest in biodiversity variables observable from space has been partly underpinned by the development of the essential biodiversity variable (EBV) framework by the Group on Earth Observations – Biodiversity Observation Network, which itself was guided by the process of identifying essential climate variables. This contribution aims to advance the development of a global biodiversity monitoring strategy by updating the previously published definition of EBV, providing a definition of satellite remote sensing (SRS) EBVs and introducing a set of principles that are believed to be necessary if ecologists and space agencies are to agree on a list of EBVs that can be routinely monitored from space. Progress toward the identification of SRS-EBVs will require a clear understanding of what makes a biodiversity variable essential, as well as agreement on who the users of the SRS-EBVs are. Technological and algorithmic developments are rapidly expanding the set of opportunities for SRS in monitoring biodiversity, and so the list of SRS-EBVs is likely to evolve over time. This means that a clear and common platform for data providers, ecologists, environmental managers, policy makers and remote sensing experts to interact and share ideas needs to be identified to support long-term coordinated actions
Cross-ancestry genome-wide association analysis of corneal thickness strengthens link between complex and Mendelian eye diseases
Central corneal thickness (CCT) is a highly heritable trait associated with complex eye diseases such as keratoconus and glaucoma. We perform a genome-wide association meta-analysis of CCT and identify 19 novel regions. In addition to adding support for known connective tissue-related pathways, pathway analyses uncover previously unreported gene sets. Remarkably, >20% of the CCT-loci are near or within Mendelian disorder genes. These included FBN1, ADAMTS2 and TGFB2 which associate with connective tissue disorders (Marfan, Ehlers-Danlos and Loeys-Dietz syndromes), and the LUM-DCN-KERA gene complex involved in myopia, corneal dystrophies and cornea plana. Using index CCT-increasing variants, we find a significant inverse correlation in effect sizes between CCT and keratoconus (r =-0.62, P = 5.30 × 10-5) but not between CCT and primary open-angle glaucoma (r =-0.17, P = 0.2). Our findings provide evidence for shared genetic influences between CCT and keratoconus, and implicate candidate genes acting in collagen and extracellular matrix regulation
ARIA 2016: Care pathways implementing emerging technologies for predictive medicine in rhinitis and asthma across the life cycle
The Allergic Rhinitis and its Impact on Asthma (ARIA) initiative commenced during a World Health Organization workshop in 1999. The initial goals were (1) to propose a new allergic rhinitis classification, (2) to promote the concept of multi-morbidity in asthma a
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