2,620 research outputs found
Re-visit of HST FUV observations of hot-Jupiter system HD 209458: No Si III detection and the need for COS transit observations
The discovery of OI atoms and CII ions in the upper atmosphere of HD 209458b,
made with the Hubble Space Telescope Imaging Spectrograph (STIS) using the
G140L grating, showed that these heavy species fill an area comparable to the
planet's Roche lobe. The derived ~10% transit absorption depths require
super-thermal processes and/or supersolar abundances. From subsequent Cosmic
Origins Spectrograph (COS) observations, CII absorption was reported with
tentative velocity signatures, and absorption by SiIII ions was also claimed in
disagreement with a negative STIS G140L detection. Here, we revisit the COS
dataset showing a severe limitation in the published results from having
contrasted the in-transit spectrum against a stellar spectrum averaged from
separate observations, at planetary phases 0.27, 0.72, and 0.49. We find
variable stellar SiIII and CII emissions that were significantly depressed not
only during transit but also at phase 0.27 compared to phases 0.72 and 0.49.
Their respective off-transit 7.5 and 3.1% flux variations are large compared to
their reported 8.2+/-1.4% and 7.8+/-1.3% transit absorptions. Significant
variations also appear in the stellar line shapes, questioning reported
velocity signatures. We furthermore present archive STIS G140M transit data
consistent with no SiIII absorption, with a negative result of 1.7+/-18.7
including ~15% variability. Silicon may still be present at lower ionization
states, in parallel with the recent detection of extended magnesium, as MgI
atoms. In this frame, the firm detection of OI and CII implying solar or
supersolar abundances contradicts the recent inference of potential x20-125
subsolar metallicity for HD 209458b.Comment: Accepted for publication in Ap
Dues notes breus de toponímia valenciana: Penyagolosa, Les Useres
Aquest treball estudia dos topònims castellonencs, Penyagolosa i Les
Useres que no han rebut encara, segons ens sembla, una explicació sencerament
versemblant. Al nostre parer, Penyagolosa ofereix com a segon element del compost
una form,a -golosa, que ha d'ésser explicada com a resultat del llat. closa o clusa,
tancada (pels cingles o barrancs, o també potser per la vegetació). D'altra banda,
Les Useres pot ésser tot simplement el desenvolupament del llat. iusaria, de baix ,
ell mateix provinent del llat. deorsum. Ambdues hipòtesis tenen l'avantatge de
no proposar cap mot d'asterisc i d'inserir els nostres topònims dins una sèrie molt
ampla i ben coneguda arreu d'Espanya i de la Romània sencera.This paper aims to
study two place-names from Castelló de la Plana (Comunitat Valenciana, Spain):
Penyagolosa and Les Useres. In our view neither of them has yet been satisfactorily
explained. In our opinion the origin of - golosa is the lat. closa or clusa, closed (by
precipices or perhaps by vegetation). On the other hand the development of late
lat. iusaria, low can explain Les Useres. Both hypotheses have a clear advantage:
they do not propose any unattested word and they relate our names with others
belonging to a very well-known group of place-names from Spain and the whole of
Romania
Quantum Simulations of Relativistic Quantum Physics in Circuit QED
We present a scheme for simulating relativistic quantum physics in circuit
quantum electrodynamics. By using three classical microwave drives, we show
that a superconducting qubit strongly-coupled to a resonator field mode can be
used to simulate the dynamics of the Dirac equation and Klein paradox in all
regimes. Using the same setup we also propose the implementation of the
Foldy-Wouthuysen canonical transformation, after which the time derivative of
the position operator becomes a constant of the motion.Comment: 13 pages, 3 figure
Emission Line Variability of the Accreting Young Brown Dwarf 2MASSW J1207334-393254: From Hours to Years
We have obtained a series of high-resolution optical spectra for the brown
dwarf 2MASSW J1207334-393254 (2M1207) using the ESO Very Large Telescope with
the UVES spectrograph during two consecutive observing nights (time resolution
of ~12 min) and the Magellan Clay telescope with the MIKE spectrograph.
Combined with previously published results, these data allow us to investigate
changes in the emission line spectrum of 2M1207 on timescales of hours to
years. Most of the emission line profiles of 2M1207 are broad, in particular
that of Halpha, indicating that the dominant fraction of the emission must be
attributed to disk accretion rather than to magnetic activity. From the Halpha
10% width we deduce a relatively stable accretion rate between
10^(-10.1...-9.8) Msun/yr for two nights of consecutive observations.
Therefore, either the accretion stream is nearly homogeneous over (sub-)stellar
longitude or the system is seen face-on. Small but significant variations are
evident throughout our near-continuous observation, and they reach a maximum
after ~8 h, roughly the timescale on which maximum variability is expected
across the rotation cycle. Together with past measurements, we confirm that the
accretion rate of 2M1207 varies by more than one order of magnitude on
timescales of months to years. Such variable mass accretion yields a plausible
explanation for the observed spread in the accretion rate vs. mass diagram. The
magnetic field required to drive the funnel flow is on the order of a few
hundred G. Despite the obvious presence of a magnetic field, no radio nor X-ray
emission has been reported for 2M1207. Possibly strong accretion suppresses
magnetic activity in brown dwarfs, similar to the findings for higher mass T
Tauri stars.Comment: accepted for publication in Ap
Preoperative digital three-dimensional planning for rhinoplasty
BACKGROUND: This report describes preoperative digital planning for rhinoplasty using a new three-dimensional (3D) radiologic viewer that allows both patients and surgeons to visualize on a common monitor the 3D real aspect of the nose in its inner and outer sides.
METHODS: In the period 2002 to 2008, 210 patients underwent rhinoplasty procedures in the authors' clinic. The patients were randomly divided into three groups according to the type of preoperative planning used: photos only, a simulated result by Adobe Photoshop, or the 3D radiologic viewer. The parameters evaluated included the number of patients that underwent surgery after the first consultation, the number of patients who asked for a reintervention, patient satisfaction (according to a test given to the patients 12 months postoperatively), the surgical time required for a functional intervention, and the improvement in nasal function by postoperative rhinomanometry and subjective evaluation.
RESULTS: Computer-aided technologies led to a higher number of patients deciding to undergo a rhinoplasty. Simulation of the postoperative results was not as useful in the postoperative period due to the higher number of reintervention requests.
CONCLUSION: The patients undergoing rhinoplasties preferred new technologies in the preoperative period. The advantages of using the 3D radiologic viewer included improved preoperative planning, reduction in intraoperative stress, a higher number of patients undergoing surgery, reduction in postoperative surgical corrections, reduction in surgical time for the functional intervention, a higher rate of improvement in nasal function, a higher percentage of postoperative satisfaction, and reduced costs
Measuring the purity of a qubit state: entanglement estimation with fully separable measurements
Given a finite number of copies of a qubit state we compute the maximum
fidelity that can be attained using joint-measurement protocols for estimating
its purity. We prove that in the asymptotic limit,
separable-measurement protocols can be as efficient as the optimal
joint-measurement one if classical communication is used. This in turn shows
that the optimal estimation of the entanglement of a two-qubit state can also
be achieved asymptotically with fully separable measurements. The relationship
between our global Bayesian approach and the quantum Cramer-Rao bound is also
discussed.Comment: 5 pages, 1 figure, RevTeX, improved versio
El plioceno continental de la depresión Guadix-Baza (Prov. Granada) y su fauna de micromamíferos. Nota preliminar
Se realiza en este trabajo una primera síntesis paleontológica y bioestratigráfica del Plioceno continental de la cuenca de Guadix-Baza. Este piso se encuentra representado en las formaciones de Gorafe-Huélago (sección de Gorafe) y Baza (secciones de Galera, Orce, Fuentenueva y Cañada de Murcia). Se establece una sucesión que oscila entre la biozona MN 14 hasta la biozona MN 17. Las zonas MN 14 y MN 15 se caracterizan por la predominancia de las especies de Múridos (Stephanomys, Occitanornys, Paraethomys). Los primeros Arvicólidos aparecen en la zona MN 15 (Mimomys cf. occitanus), caracterizando las zonas MN 16 (Kislangia cf. cappetai) y MN 17 (Mimomys cf. reidi). Algunos elementos persisten a lo largo de toda la sucesión (Castillomys, Apodemus, Eliomys, Gazella)
Jovian equatorial H2 emission from 1979-1987
Ninety two IUE observations of the Jovian equatorial region taken between 2 Dec. 1978 and 1 Feb. 1988 were averaged together by date of observation, resulting in 22 averaged spectra which were fit with a model to determine the amount of H2 Lyman band emission in the region 1552 to 1624A. The data suggest that the H2 emission may vary with time. Especially suggestive is the marked downward trend of the emission between 1983 and 1987, during which time the strength of the emission in the 1552 to 1624A region decreases by a factor of 10. Uncertainty in the existing data and a gap in the data in 1980 and 1981 preclude a positive identification of a correlation between the brightness of the H2 emission and the major solar cycle
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