A study of the effect of ionization and illumination on morphologies of planetary nebulae

We carry out a modelling study of the effect of ionization and illumination on the morphologies of planetary nebulae (PNs), aiming to investigate the hypothesis of Kwok (2010) that the bipolar and multipolar lobes of PNs can be produced by leakage of UV photons into those directions. Using photoinization code, we construct a series of nebular models consisting of a dense envelope and cones of low density. The results show that the visible morphologies of PNs may be fundamentally different from their intrinsic structures. © 2012 International Astronomical Union.published_or_final_versio

A FUSE View of the Stellar Winds of Planetary Nebula Central Stars

Since the IUE satellite produced a vast collection of high-resolution UV spectra of central stars of planetary nebulae (CSPNe), there has not been any further systematic study of the stellar winds of these stars. The high spectral resolution, sensitivity and large number of archival observations in the FUSE archive allow the study of the stellar winds of CSPNe in the far UV domain where lines of species spanning a wide excitation range can be observed. We present here a preliminary analysis of the P Cygni profiles of a sample of 60 CSPNe observed by FUSE. P Cygni profiles evidencing fast stellar winds with velocities between 200 and 4,300 km/s have been found in 40 CSPNe. In many cases, this is the first time that fast stellar winds have been reported for these PNe. A detailed study of these far-UV spectra is on-going.Comment: 4 pages, 3 figures; accepted, to appear in Publications of the Astronomical Society of Australi

Pluri-Canonical Models of Supersymmetric Curves

This paper is about pluri-canonical models of supersymmetric (susy) curves. Susy curves are generalisations of Riemann surfaces in the realm of super geometry. Their moduli space is a key object in supersymmetric string theory. We study the pluri-canonical models of a susy curve, and we make some considerations about Hilbert schemes and moduli spaces of susy curves.Comment: To appear in the proceedings of the intensive period "Perspectives in Lie Algebras", held at the CRM Ennio De Giorgi, Pisa, Italy, 201

Women and Dao in Gao Xingjian’s works

Drawing on the existing scholarly studies that have gone beyond the misogynist paradigm, such as those by Mabel Lee, Gilbert Fong, Terry Siu-han Yip, Kwok-kan Tam, and Mary Mazzilli, I intend to explore the connection between the Zen Buddhist comprehension of Dao and the representation of women in Gao Xingjian’s novels and plays. As desire and sexual relationships play a very crucial part in the realm of Zen, the role of women is inevitably bound up with self-awareness and self-reflection, which are enshrined by Gao Xingjian as necessary on the path toward individual enlightenment. According to Gao, even if women’s roles are socially and culturally constructed or sometimes become a privileged trope of defying social convention, the truth that emerges from secular life often incorporates the spirituality into women’s unique biological and psychological construction, immune to men’s full understanding but inexorably furnishing a way leading to the state of Zen

Preparation of bioactive surface via gel oxidation on titanium for biomedical application (hip joint replacement)

Titanium and its alloys are widely used as implant in biomedical applications. They have good mechanical and chemical properties, biocompatibility and biointegration with human body, but they have no ability to bond directly to natural bone. Therefore, alkali and heat treatments (gel oxidation) were introduced to improve the bioactivity of titanium by forming a mixture of sodium titanate and rutile on the surface of titanium. This method enables titanium to possess a bioactive surface which is essential to induce the apatite formation. This study aims to investigate the effects of alkali, sodium removal and heat treatments on in vitro bioactivity of titanium. UV light irradiation was used to study the effect on in vitro bioactivity of titanium. Alkalitreated titanium subjected to heat treatment in air have shown better overall in vitro performance than those treated in argon atmosphere. Therefore, the sodium removal treatment (dilute hydrochloric acid (HCl) treatment) was introduced to convert sodium titanate into anatase to improve the bioactivity of titanium treated in argon atmosphere. Thus, four samples (AT-0.5-HT500R, AT-0.5-HT600R, AT-5-HT500R and AT-5- HT600R) with different ratios of anatase to rutile were produced by varying the concentration of HCl acid treatment and heating temperature in argon atmosphere. It was found that the incorporation of sodium removal treatment has reduced two times the duration of apatite formation as compared with the conventional alkali and heat treatments. In order to further enhance the bioactivity, these samples were subjected to six different conditions of ultraviolet light irradiation and followed by in vitro bioactivity test. As a result, AT-5-HT500R (82.2% anatase and 17.8% rutile) was proven to deliver the best performance. It was confirmed that UV light irradiation enhances the bioactivity by removing hydrocarbon, inducing superhydrophilicity and forming OH groups. It was discovered that the duration of apatite formation was shortened to 7 days. Furthermore, the continuous UVA irradiation during in vitro test resulted in the acceleration of bonelike apatite formation in 3 days. It can be concluded that the sodium removal treatment and UV light irradiation give very significant impact to the formation of bonelike apatite on the titanium surfaces for biomedical applications

SpS1-Infrared and submillimetre-wave spectroscopy as probes of stellar evolution

Vol. 5 - Highlights H15 (Highlights of Astronomy)published_or_final_versionThe 27th International Astronomical Union (IAU) General Assembly, Rio de Janeiro, Brazil, 3-4 August 2009. In IAU Proceedings, 2009, v. 5, p. 508-50

String Department Student Recital, November 4, 1993

This is the concert program of the String Department Student Recital performance on Thursday, November 4, 1993 at 8:00 p.m., at the Marshall Room, 855 Commonwealth Avenue. Works performed were Mit leidenschaften Ausdruck from Sonata in A minor for Violin and Piano, Op. 105 by Robert Schumann, Adagio and Fuga from Sonata No. 1 in G minor for Solo Violin, BWV 1001 by Johann Sebastian Bach, Allegro moderato from Cello Concerto in D major, Op. 101 by Franz Joseph Haydn, Allegro moderato from Violin Concerto in D major, Op. 35 by Pyotr Ilyich Tchaikovsky, Sonata for Solo Violin, Op. 27 No. 1 by Eugène Ysaÿe, Prelude from Suite No. 5 in C minor for Solo Cello, BWV 1001 by J. S. Bach, Adagio sostenuto-Presto from Sonata No. 9 in A major for Violin and Piano,Op. 47 "Kresutzer" by Ludwig van Beethoven, Allegro molto appasionato from Violin Concerto in E minor, Op. 64 by Felix Mendelssohn-Bartholdy, Sonata for Solo Violin Op. 27 No. 5 by E. Ysaÿe, and Andante and Allegro vivace from Sonata in C major for Cello and Piano, Op. 102 No. 1 by L. v. Beethoven. Digitization for Boston University Concert Programs was supported by the Boston University Humanities Library Endowed Fund