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Endoscopic septoplasty is an alternative approach for a deviated nasal septum. Since its introduction, numerous techniques have been developed, each with its own advantages and limitations. A literature review is presented, along with our experience with endoscopic spur resection.
The Medline and Google Scholar databases were searched for relevant literature, and the records of all patients undergoing endoscopic spur resection at the University Hospitals Leuven between 2001 and 2015 were reviewed.
Results and conclusion
Endoscopic septoplasty offers improved visualisation and the option of limited flap dissection, which are particularly helpful when dealing with isolated spurs, posterior deviations and revision septoplasty. It enhances teaching and improves surgical transition to endoscopic sinus surgery. Reported success and complication rates are comparable to those seen in traditional approaches. Endoscopic spur resection, as conducted at the University Hospitals Leuven, was shown to be a quick, safe and efficient technique when dealing with isolated septal spurs, especially when combined with endoscopic sinus surgery.
This study represents the first exploration of the parasite fauna of cichlid fishes in the Mweru-Luapula subregion (Central Africa). Twelve species of cichlids and 14 species of Monogenea from three genera (Cichlidogyrus, Gyrodactylus and Scutogyrus) were collected. We present a first record of the gill parasite fauna of eight host species, Oreochromis mweruensis, Orthochromis sp. ‘Mambilima’, Sargochromis mellandi, Serranochromis angusticeps, S. stappersi, S. thumbergi and Tylochromis mylodon. The host range of ten parasite species was expanded. The study further includes the description of Cichlidogyrus consobrini sp. n. from S. mellandi and Orthochromis sp. ‘Mambilima’. A new morphotype of C. halli is characterized, and three species – C. papernastrema, C. quaestio and C. zambezensis – are redescribed. Furthermore, the biodiversity and host specificity of these parasites is compared with that of cichlid parasites from Lake Kariba and Cameroon. Two species, including C. consobrini sp. n. and a new morphotype of C. halli, are putative endemics. The parasite fauna in Bangweulu-Mweru is highly similar in species composition to Lake Kariba, but in Bangweulu-Mweru the same parasite species are more host-specific, probably because of hydrogeographical differences between the two regions.
Orbital elements for 8 non-Mira S stars (derived from CORAVEL observations and from Griffin 1984) are compared with those of barium stars. In all but one case, the mass functions are compatible with white dwarf companions. No periods shorter than 600 d are found, while the 5 orbits with 600 < P(d) < 900 all have e ≤ 0.1, in contrast with the situation prevailing for barium stars. It is suggested that the hypothesis of an evolutionary link between barium and non-Mira (no Tc) S stars can be reconciled with these differences provided that these S stars are low-mass stars populating the first giant branch instead of the asymptotic giant branch, as usually thought.
A long-term, high-accuracy, differential uvby monitoring of a sample of 19 barium stars revealed that HD 46407, a well known barium star with an orbital period of 458 d, is an eclipsing binary. The eclipse (of the companion by the barium star) was most clearly seen in November 1988, when a dip of 0.02 mag (in y) having a FWHM of about 10 d was recorded in the lightcurve. Confirmation of the eclipsing nature of HD 46407 was also obtained in February 1985 and in February 1990. A shallow secondary eclipse (extending over about 50% of the orbital period) seems to be present as well. The b – y index is marginally variable, while v – b color variations are correlated with the y variations, in the sense that the system appears redder when it is fainter. We suggest that these variations originate in the scattering of the red-giant light by dust particles trapped (in a wide ring or shell?) around the (compact) companion. The eclipsed light would then be the light of the red giant backscattered by the dust around the companion.
The Gaia-ESO Survey (GES, Gilmore et al. 2012) provides a unique opportunity to detect spectroscopically multiplicity among different populations of the Galaxy using the cross-correlation functions (CCFs). We present here the GES internal Data Release 4 (iDR4) results of the detection of double, triple and quadruple-line spectroscopic binary candidates (SBs) and discuss some peculiar systems.
The Gaia-ESO survey (GES; Gilmore et al. (2012), Randich et al. (2013)) is a spectroscopic survey complementing the Gaia mission to bring accurate radial velocities and chemical abundances for 105 stars. Merle et al. (submitted to A&A; see also this volume) developped a tool (DOE) to detect multiple peaks in the cross-correlation functions (CCFs) of GES spectra. Using the GIRAFFE HR10 and HR21 settings, we were able to compare the efficiency of our SB detection tool depending on the wavelength range and resolution. We show that a careful design of CCF masks can improve the detection rate in the HR21 settings. HR21 spectra are similar to the ones produced by the RVS spectrograph of the Gaia mission, though the lower resolution of RVS spectra may result in a lower detection efficiency than the case of HR21. Analysis of RVS spectra in the context of spectroscopic binaries can take advantage of the lessons learnt from the GES to maximize the detection rate.
S stars are s-process and C-enriched (0.5<C/O<1) red giants. Their abundances can be determined thanks to a new grid of MARCS model atmospheres covering their whole parameter range. Detailed abundance determinations in intrinsic S stars (TP-AGB) and extrinsic S stars (binary masqueraders) can provide strong constraints on the s-process nucleosynthesis: in particular, the s-process temperature can be determined using zirconium and niobium abundances, independently of stellar evolution models. Synthetic spectra of dwarf S stars have been computed and will be sought for in spectroscopic survey data, constraining their luminosity thanks to Gaia parallaxes.
Barium stars are formed via binary interaction with a former AGB companion. Observations are needed to constrain theoretical models and better understand their evolution and surface composition. We present the HR diagram of Ba and related stars, using the recently released TGAS parallaxes, and the mass distribution of the Ba giants that we derived from it.
S-type stars are late-type giants enhanced with s-process elements originating either from nucleosynthesis during the Asymptotic Giant Branch (AGB) or from a pollution by a binary companion. The former are called intrinsic S stars, and the latter extrinsic S stars. The atmospheric parameters of S stars are more numerous than those of M-type giants (C/O ratio and s-process abundances affect the thermal structure and spectral synthesis), and hence they are more difficult to derive. Nevertheless, high-resolution spectroscopic data of S stars combined with the TGAS (Tycho-Gaia Astrometric solution) parallaxes were used to derive effective temperatures, surface gravities, and luminosities. These parameters allow to locate the intrinsic and extrinsic S stars in the Hertzsprung-Russell diagram.
It is suggested that the position of BaII stars with respect to normal red giants in the (log L, 12C/13C) and ([C/Fe],12C/13C) diagrams supports the hypothesis that 13C(α,n)16O was the neutron source responsible for the synthesis of the heavy elements now present in the BaII star envelopes.
An abundance analysis of the yellow symbiotic system AG Draconis reveals it to be a metal-poor K giant ([Fe/H] = −1.3) which is enriched in the heavy s-process elements. This star thus provides a link between the symbiotic stars and the binary barium and CH stars which are also s-process enriched. These binary systems, which exhibit overabundances of the heavy elements, owe their abundance peculiarities to mass transfer from thermally-pulsing asymptotic giant branch stars, which have since evolved to become white-dwarf companions of the cool stars we now view as the chemically peculiar primaries. A comparison of the heavy-element abundance distribution in AG Dra with theoretical nucleosynthesis calculations shows that the s-process is defined by a relatively large neutron exposure (τ = 1.3 mb−1), while an analysis of the rubidium abundance suggests that the s-process occurred at a neutron density of about 2 × 108 cm−3. The derived spectroscopic orbit of AG Dra is similar to the orbits of barium and CH stars. Because the luminosity function of low-metallicity K giants is skewed towards higher luminosities by about 2 magnitudes relative to solar-metallicity giants, it is argued that the lower metallicity K giants have larger mass-loss rates. It is this larger mass-loss rate that drives the symbiotic phenomena in AG Dra and we suggest that the other yellow symbiotic stars are probably low-metallicity objects as well.
An AGB star in a binary system is likely to pollute its companion with carbon- and s-process-rich matter. After the AGB star has faded into an unconspicuous white dwarf, the polluted companion enters the zoo of stars with chemical peculiarities. In this paper, the progeny of AGB stars in binary systems are identified among existing spectroscopic classes (Abell 35-like, binary post-AGB, WIRRing, dwarf Ba and C, subgiant CH, Ba, CH, S, yellow symbiotics) and their filiation is discussed from the properties of their eccentricity – period diagrams.
We report the results of monitoring the radial velocities of 31 confirmed Ba dwarfs and CH subgiants, showing that about 27 of them have a variable radial velocity. Therefore, mass transfer in a binary most probably explains their chemical anomalies, as for the Ba giants. The orbital parameters of the 14 systems having sufficient phase coverage are very similar to those of the Ba giants. Whether the CH subgiants and Ba dwarfs may become Ba giants is discussed briefly. Most of the marginal Ba dwarfs listed by Edvardsson et al. (1993) are single, so that their chemical peculiarity, if real, cannot be due to binary evolution.
Systematic radial velocity monitoring programs revealed that all optically bright, high-latitude post-AGB stars that show a near-IR excess in their energy distribution are binaries (see the contribution of R. Waters et al. in these proceedings). A standard AGB evolution for the shorter period objects seems, however, impossible since the orbits are too small to accommodate an AGB star! Non-standard phenomena connected to the specific binary nature have to be invoked in order to understand these systems.