1,853 research outputs found
THROES: a caTalogue of HeRschel Observations of Evolved Stars. I. PACS range spectroscopy
This is the first of a series of papers presenting the THROES (A caTalogue of
HeRschel Observations of Evolved Stars) project, intended to provide a
comprehensive overview of the spectroscopic results obtained in the
far-infrared (55-670 microns) with the Her- schel space observatory on
low-to-intermediate mass evolved stars in our Galaxy. Here we introduce the
catalogue of interactively reprocessed PACS (Photoconductor Array Camera and
Spectrometer) spectra covering the 55-200 microns range for 114 stars in this
category for which PACS range spectroscopic data is available in the Herschel
Science Archive (HSA). Our sample includes objects spanning a range of
evolutionary stages, from the asymptotic giant branch to the planetary nebula
phase, displaying a wide variety of chemical and physical properties. The
THROES/PACS catalogue is accessible via a dedicated web-based inter- face
(https://throes.cab.inta-csic.es/) and includes not only the science-ready
Herschel spectroscopic data for each source, but also complementary photometric
and spectroscopic data from other infrared observatories, namely IRAS (Infrared
Astronomical Satellite), ISO (Infrared Space Observatory) or AKARI, at
overlapping wavelengths. Our goal is to create a legacy-value Herschel dataset
that can be used by the scientific community in the future to deepen our
knowledge and understanding of these latest stages of the evolution of
low-to-intermediate mass stars.Comment: 38 page
Model and neural control of the depth of anesthesia during surgery
At present, the experimentation of anesthetic drugs on
patients requires a regulation protocol, and the response of each patient
to several doses of entry drug must be well known. Therefore, the
development of pharmacological dose control systems is a promising
field of research in anesthesiology.
In this paper it has been developed a non-linear compartmental
pharmacokinetic-pharmacodynamical model which describes the
anesthesia depth effect on a sufficiently reliable way over a set of
patients with the depth effect quantified by the Bi-Spectral Index.
Afterwards, an Artificial Neural Network (ANN) predictive controller
has been designed based on the depth of anesthesia model so as to keep
the patient on the optimum condition while he undergoes surgical
treatment.
For the purpose of quantifying the efficiency of the neural predictive
controller, a classical proportional-integral-derivative controller has
also been developed to compare both strategies. Results show the
superior performance of predictive neural controller during Bi-
Spectral Index reference tracking.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
COLECCIÓN MARTÍN MORENO. CRONISTA OFICIAL DE GRAN CANARIA [Material gráfico]
Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte. Subdirección General de Coordinación Bibliotecaria, 201
Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes
This is the second paper of a series making use of Herschel/PACS spectroscopy
of evolved stars in the THROES catalogue to study the inner regions of their
circumstellar envelopes (CSEs). We analyze the CO emission spectra, including a
large number of high- CO lines (from =14-13 to =45-44), as a proxy for
the warm molecular gas in the CSEs of a sample of bright carbon-rich stars
spanning different evolutionary stages from the Asymptotic Giant Branch (AGB)
to the young planetary nebulae (PNe) phase. We use the rotational diagram (RD)
to derive rotational temperatures () and masses () of
the envelope layers where the CO transitions arise. We also obtain a first
order estimate of the mass-loss rates and assess the impact of the opacity
correction for a range of characteristic envelope radii. We use multi-epoch
spectra for the well studied C-rich envelope IRC+10216 to investigate the
impact of CO flux variability on the values of and .
PACS sensitivity allowed the study of higher rotational numbers than before,
indicating the presence of a significant amount of warmer gas (200-900 K)
not traceable with lower- CO observations at sub-mm/mm wavelengths. The
masses are in the range , anti-correlated
with temperature. For some strong CO emitters we infer a double temperature
(warm 400 K and hot 820 K) component. From
the analysis of IRC+10216, we corroborate that the effect of line variability
is perceptible on the of the hot component only, and certainly
insignificant on and, hence, the mass-loss rate. Therefore, the
parameters derived from the RD are robust even when strong line flux
variability occurs, with the major source of uncertainty in the estimate of the
mass-loss rate being the size of the CO-emitting volume.Comment: accepted in A&
Temporal evolution of a driven optomechanical system in the strong coupling regime
We obtain a time-evolution operator for a forced optomechanical quantum
system using Lie algebraic methods when the normalized coupling between the
electromagnetic field and a mechanical oscillator, , is not
negligible compared to one. Due to the forcing term, the interaction picture
Hamiltonian contains the number operator in the exponents, and in order to deal
with it, we approximate these exponentials by their average values taken
between initial coherent states. Our approximation is justified when we compare
our results with the numerical solution of the number of photons, phonons,
Mandel parameter, and the Wigner function, showing an excellent agreement.Comment: 21 pages, 11 figure
- …