9,639 research outputs found
CCD Photometry of Delta Scuti stars 7 Aql and 8 Aql
As a continuation of the study of the Delta Scuti stars 7 Aql and 8 Aql; new
CCD photometric data were acquired in 2007. We present a period analysis on
these data that confirm the dominant modes detected in each star in the
framework of the STEPHI XII campaign in 2003.Comment: 9 pages, 7 figures, 2 tables; Accepted for publication in
Communications in Asteroseismology, Vol 153, 200
T-duality in Massive Integrable Field Theories: The Homogeneous and Complex sine-Gordon Models
The T-duality symmetries of a family of two-dimensional massive integrable
field theories defined in terms of asymmetric gauged Wess-Zumino-Novikov-Witten
actions modified by a potential are investigated. These theories are examples
of massive non-linear sigma models and, in general, T-duality relates two
different dual sigma models perturbed by the same potential. When the
unperturbed theory is self-dual, the duality transformation relates two
perturbations of the same sigma model involving different potentials. Examples
of this type are provided by the Homogeneous sine-Gordon theories, associated
with cosets of the form G/U(1)^r where G is a compact simple Lie group of rank
r. They exhibit a duality transformation for each element of the Weyl group of
G that relates two different phases of the model. On-shell, T-duality provides
a map between the solutions to the equations of motion of the dual models that
changes Noether soliton charges into topological ones. This map is carefully
studied in the complex sine-Gordon model, where it motivates the construction
of Bogomol'nyi-like bounds for the energy that provide a novel characterisation
of the already known one-solitons solutions where their classical stability
becomes explicit.Comment: 29 pages, LaTe
A smart distribution toolbox for distribution system planning
Paper 1623The distribution system planner should be able to coordinate smart grid solutions in order to find cost effective expansions plans. These plans should be able to deal with new added system uncertainties from renewable production and consumers while guaranteeing power quality and availability of supply. This paper proposes a structure for distribution systems planning oriented to help the planner in deciding how to make use of smart solutions for achieving the described task. Here, the concept of a system planning toolbox is introduced and supported with a review of relevant works implementing smart solutions. These are colligated in a way that the system planner can foresee what to expect with their combined implementation. Future developments in this subject should attempt to theorize a practical algorithm in an optimization and decision making context.postprin
Repression of the Hox gene abd-A by ELAV-mediated Transcriptional Interference
Intergenic transcription is a common feature of eukaryotic genomes and performs important and diverse cellular functions. Here, we investigate the iab-8 ncRNA from the Drosophila Bithorax Complex and show that this RNA is able to repress the transcription of genes located at its 3’ end by a sequence-independent, transcriptional interference mechanism. Although this RNA is expressed in the early epidermis and CNS, we find that its repressive activity is limited to the CNS, where, in wild-type embryos, it acts on the Hox gene, abd-A, located immediately downstream of it. The CNS specificity is achieved through a 3’ extension of the transcript, mediated by the neuronal-specific, RNA-binding protein, ELAV. Loss of ELAV activity eliminates the 3’ extension and results in the ectopic activation of abd-A. Thus, a tissue-specific change in the length of a ncRNA is used to generate a precise pattern of gene expression in a higher eukaryote
Modelagem para otimização da fertilização e calagem na cultura de cana-de-açúcar.
Resumo: A disponibilidade de informações necessárias para modelar a demanda de certos nutrientes que se espera da produtividade permite o desenvolvimento de um sistema para o cálculo do balanço nutricional e recomendação de corretivos e fertilizantes para a cana. O equilĂbrio entre o que Ă© necessário (aplicando a planta), e que podem estar disponĂveis (fonte terra) Ă© a base para o desenvolvimento do sistema. O cálculo do balanço de nutrientes indica a necessidade, ou nĂŁo, bem como a aplicação de calcário e fertilizantes.SIAGRO 2014
p-Branes from Generalized Yang-Mills Theory
We consider the reduced, quenched version of a generalized Yang-Mills action
in 4k-dimensional spacetime. This is a new kind of matrix theory which is
mapped through the Weyl-Wigner-Moyal correspondence into a field theory over a
non-commutative phase space. We show that the ``classical'' limit of this field
theory is encoded into the effective action of an open, (4k-1)-dimensional,
bulk brane enclosed by a dynamical, Chern-Simons type, (4k-2)-dimensional,
boundary brane. The bulk action is a pure volume term, while the boundary
action carries all the dynamical degrees of freedom.Comment: 8 pages, LaTeX 2e, no figure
Group, subgroup, and person specific symptom associations in individuals at different levels of risk for psychosis:A combination of theory-based and data-driven approaches
Introduction Dynamics between symptoms may reveal insights into mechanisms underlying the development of psychosis. We combined a top-down (theory-based) and bottom-up (data-driven) approach to examine which symptom dynamics arise on group-level, on subgroup levels, and on individual levels in early clinical stages. We compared data-driven subgroups to theory-based subgroups, and explored how the data-driven subgroups differed from each other. Methods Data came from N = 96 individuals at risk for psychosis divided over four subgroups (n1 = 25, n2 = 27, n3 = 24, n4 = 20). Each subsequent subgroup represented a higher risk for psychosis (clinical stages 0-1b). All individuals completed 90 days of daily diaries, totaling 8640 observations. Confirmatory Subgrouping Group Iterative Multiple Model Estimation (CS-GIMME) and subgrouping (S-)-GIMME were used to examine group-level associations, respectively, theory-based and data-driven subgroups associations, and individual-specific associations between daily reports of depression, anxiety, stress, irritation, psychosis, and confidence. Results One contemporaneous group path between depression and confidence was identified. CS-GIMME identified several subgroup-specific paths and some paths that overlapped with other subgroups. S-GIMME identified two data-driven subgroups, with one subgroup reporting more psychopathology and lower social functioning. This subgroup contained most individuals from the higher stages and those with more severe psychopathology from the lower stages, and shared more connections between symptoms. Discussion Although subgroup-specific paths were recovered, no clear ordering of symptom patterns was found between different early clinical stages. Theory-based subgrouping distinguished individuals based on psychotic severity, whereas data-driven subgrouping distinguished individuals based on overall psychopathological severity. Future work should compare the predictive value of both methods
Properties of hyperons in chiral perturbation theory
The development of chiral perturbation theory in hyperon phenomenology has
been troubled due to power-counting subtleties and to a possible slow
convergence. Furthermore, the presence of baryon-resonances, e.g. the
lowest-lying decuplet, complicates the approach, and the inclusion of their
effects may become necessary. Recently, we have shown that a fairly good
convergence is possible using a renormalization prescription of the
loop-divergencies which recovers the power counting, is covariant and
consistent with analyticity. Moreover, we have systematically incorporated the
decuplet resonances taking care of both power-counting and
problems. A model-independent understanding of diferent properties including
the magnetic moments of the baryon-octet, the electromagnetic structure of the
decuplet resonances and the hyperon vector coupling , has been
successfully achieved within this approach. We will briefly review these
developments and stress the important role they play for an accurate
determination of the Cabibbo-Kobayashi-Maskawa matrix element from
hyperon semileptonic decay data.Comment: To appear in HypX Proceeding
The MIDAS telescope for microwave detection of ultra-high energy cosmic rays
We present the design, implementation and data taking performance of the
MIcrowave Detection of Air Showers (MIDAS) experiment, a large field of view
imaging telescope designed to detect microwave radiation from extensive air
showers induced by ultra-high energy cosmic rays. This novel technique may
bring a tenfold increase in detector duty cycle when compared to the standard
fluorescence technique based on detection of ultraviolet photons. The MIDAS
telescope consists of a 4.5 m diameter dish with a 53-pixel receiver camera,
instrumented with feed horns operating in the commercial extended C-Band (3.4
-- 4.2 GHz). A self-trigger capability is implemented in the digital
electronics. The main objectives of this first prototype of the MIDAS telescope
- to validate the telescope design, and to demonstrate a large detector duty
cycle - were successfully accomplished in a dedicated data taking run at the
University of Chicago campus prior to installation at the Pierre Auger
Observatory.Comment: 13 pages, 18 figure
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