Stable retrograde orbits around the triple system 2001 SN263

The NEA 2001 SN263 is the target of the ASTER MISSION - First Brazilian Deep Space Mission. Araujo et al. (2012), characterized the stable regions around the components of the triple system for the planar and prograde cases. Knowing that the retrograde orbits are expected to be more stable, here we present a complementary study. We now considered particles orbiting the components of the system, in the internal and external regions, with relative inclinations between $90^{\circ}< I \leqslant180^{\circ}$, i.e., particles with retrograde orbits. Our goal is to characterize the stable regions of the system for retrograde orbits, and then detach a preferred region to place the space probe. For a space mission, the most interesting regions would be those that are unstable for the prograde cases, but stable for the retrograde cases. Such configuration provide a stable region to place the mission probe with a relative retrograde orbit, and, at the same time, guarantees a region free of debris since they are expected to have prograde orbits. We found that in fact the internal and external stable regions significantly increase when compared to the prograde case. For particles with $e=0$ and $I=180^{\circ}$, we found that nearly the whole region around Alpha and Beta remain stable. We then identified three internal regions and one external region that are very interesting to place the space probe. We present the stable regions found for the retrograde case and a discussion on those preferred regions. We also discuss the effects of resonances of the particles with Beta and Gamma, and the role of the Kozai mechanism in this scenario. These results help us understand and characterize the stability of the triple system 2001 SN263 when retrograde orbits are considered, and provide important parameters to the design of the ASTER mission.Comment: 11 pages, 8 figures. Accepted for publication in MNRAS - 2015 March 1

Bilinear and quadratic Hamiltonians in two-mode cavity quantum electrodynamics

In this work we show how to engineer bilinear and quadratic Hamiltonians in cavity quantum electrodynamics (QED) through the interaction of a single driven two-level atom with cavity modes. The validity of the engineered Hamiltonians is numerically analyzed even considering the effects of both dissipative mechanisms, the cavity field and the atom. The present scheme can be used, in both optical and microwave regimes, for quantum state preparation, the implementation of quantum logical operations, and fundamental tests of quantum theory.Comment: 11 pages, 3 figure

Nonadiabatic coherent evolution of two-level systems under spontaneous decay

In this paper we extend current perspectives in engineering reservoirs by producing a time-dependent master equation leading to a nonstationary superposition equilibrium state that can be nonadiabatically controlled by the system-reservoir parameters. Working with an ion trapped inside a nonindeal cavity we first engineer effective Hamiltonians that couple the electronic states of the ion with the cavity mode. Subsequently, two classes of decoherence-free evolution of the superposition of the ground and decaying excited levels are achieved: those with time-dependent azimuthal or polar angle. As an application, we generalise the purpose of an earlier study [Phys. Rev. Lett. 96, 150403 (2006)], showing how to observe the geometric phases acquired by the protected nonstationary states even under a nonadiabatic evolution.Comment: 5 pages, no figure

Superscars in the LiNC=LiCN isomerization reaction

We demonstrate the existence of superscarring in the LiNC=LiCN isomerization reaction described by a realistic potential interaction in the range of readily attainable experimental energies. This phenomenon arises as the effect of two periodic orbits appearing "out of the blue"in a saddle--node bifurcation taking place in the dynamics of the system. Potential practical consequences of this superlocalization in the corresponding wave functions are also considered.Comment: 6 pages, 5 figures. to appear in EP

High coercivity induced by mechanical milling in cobalt ferrite powders

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 treated by mechanical milling with different grinding balls. The cobalt ferrite nanoparticles were prepared using a simple hydrothermal method and annealed at 500oC. The non-milled sample presented coercivity of about 1.9 kOe, saturation magnetization of 69.5 emu/g, and a remanence ratio of 0.42. After milling, two samples attained coercivity of 4.2 and 4.1 kOe, and saturation magnetization of 67.0 and 71.4 emu/g respectively. The remanence ratio MR/MS for these samples increase to 0.49 and 0.51, respectively. To investigate the influence of the microstructure on the magnetic behavior of these samples, we used X-ray powder diffraction (XPD), transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). The XPD analysis by the Williamson-Hall plot was used to estimate the average crystallite size and strain induced by mechanical milling in the samples

Sistematização de metadados de parcelas permanentes.

Resumo

Oral appliances and functional orthopaedic appliances for obstructive sleep apnoea in children

Background Apnoea is a breathing disorder marked by the absence of airflow at the nose or mouth. In children, risk factors include adenotonsillar hypertrophy, obesity, neuromuscular disorders and craniofacial anomalies. The most common treatment for obstructive sleep apnoea syndrome (OSAS) in childhood is adeno-tonsillectomy. This approach is limited by its surgical risks, mostly in children with comorbidities and, in some patients, by recurrence that can be associated with craniofacial problems. Oral appliances and functional orthopaedic appliances have been used for patients who have OSAS and craniofacial anomalies because they hold the lower jaw (mandible) forwards which potentially enlarges the upper airway and increases the upper airspace, improving the respiratory function. Objectives To assess the effects of oral appliances or functional orthopaedic appliances for obstructive sleep apnoea in children. Search methods We searched the following electronic databases: Cochrane Oral Health's Trials Register (to 7 April 2016)Cochrane Central Register of Controlled Trials (CENTRAL2016, Issue 3) in the Cochrane Library (searched 7 April 2016)MEDLINE Ovid (1946 to 7 April 2016)Embase Ovid (1980 to 7 April 2016)LILACS BIREME (from 1982 to 7 April 2016)BBO BIREME (from 1986 to 7 April 2016) and SciELO Web of Science (from 1997 to 7 April 2016). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials on 7 April 2016. We placed no restrictions on the language or date of publication when searching the electronic databases. Selection criteria All randomised or quasi-randomised controlled trials comparing all types of oral and functional orthopaedic appliances with placebo or no treatment, in children 15 years old or younger. Primary outcome: reduction of apnoea to less than one episode per hour. Secondary outcomes: dental and skeletal relationship, sleep parameters improvement, cognitive and phonoaudiological function, behavioural problems, quality of life, side effects (tolerability) and economic evaluation. Data collection and analysis Two review authors screened studies and extracted data independently. Authors were contacted for additional information. We calculated risk ratios with 95% confidence intervals for all important dichotomous outcomes. We assessed the quality of the evidence of included studies using GRADEpro software. Main results The initial search identified 686 trials. Only one trial, reporting the results from a total of 23 children and comparing an oral appliance to no treatment, was suitable for inclusion in the review. The trial assessed apnoea-hypopnoea, daytime symptoms (sleepiness, irritability, tiredness, school problems, morning headache, thirstiness in the morning, oral breathing and nasal stuffiness) and night-time symptoms (habitual snoring, restless sleep and nightmares measured by questionnaire). Results were inconsistent across outcomes measures and time points. The evidence was considered very low quality. Authors' conclusions There is insufficient evidence to support or refute the effectiveness of oral appliances and functional orthopaedic appliances for the treatment of obstructive sleep apnoea in children. Oral appliances or functional orthopaedic appliances may be considered in specified cases as an auxiliary in the treatment of children who have craniofacial anomalies which are risk factors for apnoea.Brazilian Cochrane Center, BrazilNational Institute for Health Research (NIHR), UKNIHRCochrane Oral Health Global AllianceNeuro-Sono SleepCenter, Department of Neurology,Universidade Federal de São Paulo, Rua Americo Salvador Novelli 508, BR-08210090 Sao Paulo, SP, BrazilDepartment of Neurology,Universidade Federal de São Paulo, Rua Americo Salvador Novelli 508, BR-08210090 Sao Paulo, SP, BrazilExternal sourcesBrazilian Cochrane Center, Brazil.National Institute for Health Research (NIHR), UK.This project was supported by the NIHR, via Cochrane Infrastructure funding to Cochrane Oral Health. The views and opinions expressed therein are those of the review authors and do not necessarily reflect those of the Systematic Reviews Programme, the NIHR, the NHS or the Department of Health.Cochrane Oral Health Global Alliance, Other.The production of Cochrane Oral Health reviews has been supported financially by our Global Alliance since 2011 (ohg.cochrane.org/partnerships-alliances). Contributors over the last year have been: British Association for the Study of Community Dentistry, UKBritish Society of Paediatric Dentistry, UKCentre for Dental Education and Research at All India Institute of Medical Sciences, IndiaNational Center for Dental Hygiene Research & Practice, USANew York University College of Dentistry, USANHS Education for Scotland, UK.Web of Scienc

Plasma membrane remodeling and caveolae disruption during cAMP-induced lipid mobilization in adipocytes

International audienc

Isotropic extensions of the vacuum solutions in general relativity

In this work, we obtain isotropic extensions of the usual spherically symmetric vacuum geometries in general relativity. Exact and perturbative solutions are derived. The classes of geometries obtained include black holes in compact and noncompact universes, wormholes in the interior region of cosmological horizons, and anti-de Sitter geometries with excess/deficit solid angle. The tools developed here are applicable in more general contexts.Comment: 12 pages, 6 figures. Version to be published in Physical Review

Exchange-spring behavior in bimagnetic CoFe2O4/CoFe2 nanocomposite

In this work we report a study of the magnetic behavior of ferrimagnetic oxide CoFe2O4 and ferrimagnetic oxide/ferromagnetic metal CoFe2O4/CoFe2 nanocomposites. The latter compound is a good system to study hard ferrimagnet/soft ferromagnet exchange coupling. Two steps were used to synthesize the bimagnetic CoFe2O4/CoFe2 nanocomposites: (i) first preparation of CoFe2O4 nanoparticles using the a simple hydrothermal method and (ii) second reduction reaction of cobalt ferrite nanoparticles using activated charcoal in inert atmosphere and high temperature. The phase structures, particle sizes, morphology, and magnetic properties of CoFe2O4 nanoparticles have been investigated by X-Ray diffraction (XRD), Mossbauer spectroscopy (MS), transmission electron microscopy (TEM), and vibrating sample magnetometer (VSM) with applied field up to 3.0 kOe at room temperature and 50K. The mean diameter of CoFe2O4 particles is about 16 nm. Mossbauer spectra reveal two sites for Fe3+. One site is related to Fe in an octahedral coordination and the other one to the Fe3+ in a tetrahedral coordination, as expected for a spinel crystal structure of CoFe2O4. TEM measurements of nanocomposite show the formation of a thin shell of CoFe2 on the cobalt ferrite and indicate that the nanoparticles increase to about 100 nm. The magnetization of nanocomposite showed hysteresis loop that is characteristic of the exchange spring systems. A maximum energy product (BH)max of 1.22 MGOe was achieved at room temperature for CoFe2O4/CoFe2 nanocomposites, which is about 115% higher than the value obtained for CoFe2O4 precursor. The exchange-spring interaction and the enhancement of product (BH)max in nanocomposite CoFe2O4/CoFe2 have been discussed.Comment: 9 pages, 10 figure