Mesa redonda sobre política exterior de Chile

Participan: Hernán Felipe Errázuriz, Teodoro Ribera, Alberto van Klaveren, Angel Flisfisch, Juan Gabriel Valdés

Lenses in the forest: cross-correlation of the Lyman-alpha flux with CMB lensing

We present a theoretical estimate for a new observable: the cross-correlation between the Lyman-alpha flux fluctuations in quasar (QSO) spectra and the convergence of the cosmic microwave background (CMB) as measured along the same line-of-sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line-of-sight and peaks at somewhat smaller redshifts than those probed by the Lyman-alpha forest, we estimate a total signal-to-noise of 9 for cross-correlating QSO spectra of SDSS-III with Planck and of 20 for cross-correlating with a future polarization based CMB experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross-correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed by observations.Comment: 5 pages, 4 figures, matches published versio

Day-case management of chronic suppurative otitis media with cholesteatoma with canal wall down technique surgery: long-term follow-up

The overall number of day-case otologic surgery cases is increasing; however, there is limited experience about performing canal wall down tympanoplasty in patients with chronic suppurative otitis media with cholesteatoma in this setting. The objective of this study was to assess the success of this technique as day-case surgery in terms of results and complications over an 8-year follow up period. We included in this study 42 patients undergoing canal wall down technique tympanoplasty surgery for chronic suppurative otitis media with cholesteatoma performed as day cases during a 2-year period. 30 cases (71.4%) were discharged on the day of surgery, whereas 12 cases (28.6%) were hospitalized and discharged the day after. The principal reasons for failure of discharge on the day of surgery were asthenia (6 cases), vertigo and asthenia (4 cases), undetermined (2 cases). Based on our experience, with a proper preoperative selection, assessment and screening of the patients, mastoidectomy with timpanoplasty for chronic suppurative otitis media with cholesteatoma can be carried out in a day surgery setting with no significant effects on effectiveness of surgery, post-operative symptoms and relapse of disease even in the long term

Tolerance and hyperaccumulation of a mixture heavy metals (Cu, Pb , Hg and Zn) by four aquatic macrophytes

El propósito de este trabajo fue comparar la tolerancia a la exposición de una mezcla de los metales (Cu2+, Pb2+, Hg2+ y Zn2+) así como el nivel de hiperacumulación en Typha latifolia, Lemna minor, Eichhornia crassipes y Myriophyllum acuaticum, para proponer un sistema de bioacumulación selectiva que permita la biorremediación eficiente de cuerpos de agua contaminadosIn the present investigation, four macrophytes, namely Typha latifolia (L.), Lemna minor (L.), Eichhornia crassipes (Mart.) Solms-Laubach, and Myriophyllum aquaticum (Vell.) Verdc, were evaluated for their heavy metal (Cu, Pb, Hg, and Zn) hyperaccumulation potential under laboratory conditions. Tolerance analyses were performed for 7 days of exposure at five different treatments of the metals mixture (CuC2, HgC2, PbC2, and ZnC2). The production of chlorophyll and carotenoids was determined at the end of each treatment. L. minor revealed to be sensitive, because it did not survive in all the tested concentrations after 72 hours of exposure. E. crassipes and M. aquaticum displayed the highest tolerance to the metals mixture. For the most tolerant species of aquatic macrophytes, The removal kinetics of E. crassipes and M. aquaticum was carried out, using the following mixture of metals: Cu (0.5 mg/L) and Hg, Pb, and Zn 0.25 mg/L. The obtained results revealed that E. crassipes can remove 99.80% of Cu, 97.88% of Pb, 99.53% of Hg, and 94.37% of Zn. M. aquaticum withdraws 95.2% of Cu, 94.28% of Pb, 99.19% of Hg, and 91.91% of Zn. The obtained results suggest that these two species of macrophytes could be used for the phytoremediation of this mixture of heavy metals from the polluted water bodies

Ranking Models in Conjoint Analysis

In this paper we consider the estimation of probabilisticranking models in the context of conjoint experiments. By usingapproximate rather than exact ranking probabilities, we do notneed to compute high-dimensional integrals. We extend theapproximation technique proposed by \\citet{Henery1981} in theThurstone-Mosteller-Daniels model for any Thurstone orderstatistics model and we show that our approach allows for aunified approach. Moreover, our approach also allows for theanalysis of any partial ranking. Partial rankings are essentialin practical conjoint analysis to collect data efficiently torelieve respondents' task burden.conjoint experiments;partial rankings;thurstone order statistics model