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Search Results: 1 - 10 of 37411 matches for " Ronny Zhao-Geisler "
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High-resolution CO observation of the carbon star CIT 6 revealing the spiral structure and a nascent bipolar outflow
Hyosun Kim,Sheng-Yuan Liu,Naomi Hirano,Ronny Zhao-Geisler,Alfonso Trejo,Hsi-Wei Yen,Ronald E. Taam,Francisca Kemper,Jongsoo Kim,Do-Young Byun,Tie Liu
Physics , 2015,
Abstract: CIT 6 is a carbon star in the transitional phase from the asymptotic giant branch (AGB) to the protoplanetary nebulae (pPN). Observational evidences of two point sources in the optical, circumstellar arc segments in an HC$_3$N line emission, and a bipolar nebula in near-infrared provide strong support for the presence of a binary companion. Hence, CIT 6 is very attractive for studying the role of companions in the AGB-pPN transition. We have carried out high resolution $^{12}$CO $J=2-1$ and $^{13}$CO $J=2-1$ observations of CIT 6 with the Submillimeter Array combined with the Submillimeter Telescope (single-dish) data. The $^{12}$CO channel maps reveal a spiral-shell pattern connecting the HC$_3$N segments in a continuous form, and an asymmetric outflow corresponding to the near-infrared bipolar nebula. Rotation of the $^{12}$CO channel peak position may be related to the inner spiral winding and/or the bipolar outflow. An eccentric orbit binary is suggested for the presences of an anisotropic mass loss to the west and a double spiral pattern. The lack of interarm emission to the west may indicate a feature corresponding to the periastron passage of a highly eccentric orbit of the binary. Spatially-averaged radial and spectral profiles of $^{12}$CO $J=2-1$ and $^{13}$CO $J=2-1$ are compared with simple spherical radiative transfer models, suggesting a change of $^{12}$CO/$^{13}$CO abundance ratio from $\sim30$ to $\sim50$ inward in the CSE of CIT 6. The millimeter continuum emission is decomposed into extended dust thermal emission (spectral index $\sim-2.4$) and compact emission from radio photosphere (spectral index $\sim-2.0$).
Dust and molecular shells in asymptotic giant branch stars - Mid-infrared interferometric observations of R Aql, R Aqr, R Hya, W Hya and V Hya
R. Zhao-Geisler,A. Quirrenbach,R. Koehler,B. Lopez
Physics , 2012, DOI: 10.1051/0004-6361/201118150
Abstract: Mid-IR (8 - 13 micron) interferometric data of four oxygen-rich AGB stars (R Aql, R Aqr, R Hya, and W Hya) and one carbon-rich AGB star (V Hya) were obtained with MIDI/VLTI between April 2007 and September 2009. The spectrally dispersed visibility data are analyzed by fitting a circular fully limb-darkened disk (FDD). Results. The FDD diameter as function of wavelength is similar for all oxygen-rich stars. The apparent size is almost constant between 8 and 10 micron and gradually increases at wavelengths longer than 10 micron. The apparent FDD diameter in the carbon-rich star V Hya essentially decreases from 8 to 12 micron. The FDD diameters are about 2.2 times larger than the photospheric diameters estimated from K-band observations found in the literature. The silicate dust shells of R Aql, R Hya and W Hya are located fairly far away from the star, while the silicate dust shell of R Aqr and the amorphous carbon (AMC) and SiC dust shell of V Hya are found to be closer to the star at around 8 photospheric radii. Phase-to-phase variations of the diameters of the oxygen-rich stars could be measured and are on the order of 15% but with large uncertainties. From a comparison of the diameter trend with the trends in RR Sco and S Ori it can be concluded that in oxygen-rich stars the overall larger diameter originates from a warm molecular layer of H2O, and the gradual increase longward of 10 micron can be most likely attributed to the contribution of a close Al2O3 dust shell. The chromatic trend of the Gaussian FWHM in V Hya can be explained with the presence of AMC and SiC dust. The observations suggest that the formation of amorphous Al2O3 in oxygen- rich stars occurs mainly around or after visual minimum. However, no firm conclusions can be drawn concerning the mass-loss mechanism.
The mid-infrared diameter of W Hydrae
R. Zhao-Geisler,A. Quirrenbach,R. Koehler,B. Lopez,C. Leinert
Physics , 2011, DOI: 10.1051/0004-6361/201016310
Abstract: Mid-infrared (8-13 microns) interferometric data of W Hya were obtained with MIDI/VLTI between April 2007 and September 2009, covering nearly three pulsation cycles. The spectrally dispersed visibility data of all 75 observations were analyzed by fitting a circular fully limb-darkened disk (FDD) model to all data and individual pulsation phases. Asymmetries were studied with an elliptical FDD. Modeling results in an apparent angular FDD diameter of W Hya of about (80 +/- 1.2) mas (7.8 AU) between 8 and 10 microns, which corresponds to an about 1.9 times larger diameter than the photospheric one. The diameter gradually increases up to (105 +/- 1.2) mas (10.3 AU) at 12 microns. In contrast, the FDD relative flux fraction decreases from (0.85 +/- 0.02) to (0.77 +/- 0.02), reflecting the increased flux contribution from a fully resolved surrounding silicate dust shell. The asymmetric character of the extended structure could be confirmed. An elliptical FDD yields a position angle of (11 +/- 20) deg and an axis ratio of (0.87 +/- 0.07). A weak pulsation dependency is revealed with a diameter increase of (5.4 +/- 1.8) mas between visual minimum and maximum, while detected cycle-to-cycle variations are smaller. W Hya's diameter shows a behavior that is very similar to the Mira stars RR Sco and S Ori and can be described by an analogous model. The constant diameter part results from a partially resolved stellar disk, including a close molecular layer of H2O, while the increase beyond 10 microns can most likely be attributed to the contribution of a spatially resolved nearby Al2O3 dust shell.
Millimetric and sub-millimetric observations of IRAS 05327+3404 "Holoea" in M36
O. Morata,Y. J. Kuan,P. T. P. Ho,H. C. Huang,E. A. Magnier,R. Zhao-Geisler
Physics , 2013, DOI: 10.1088/0004-6256/146/3/49
Abstract: The transition between the proto-star, Class I, and the pre-main sequence star, Class II, phases is still one of the most uncertain, and important, stages in the knowledge of the process of formation of an individual star, because it is the stage that determines the final mass of the star. We observed the YSO "Holoea", associated with IRAS 05327+3404, which was classified as an object in transition between the Class I and Class II phases with several unusual properties, and appears to be surrounded by large amounts of circumstellar material. We used the SMA and BIMA telescopes at millimeter and sub-millimeter wavelengths to observe the dust continuum emission and the CO (1-0) and (2-1), HCO+ (1-0) and (3-2), and HCN (1-0) transitions in the region around IRAS 05327+3404. We detected two continuum emission peaks at 1.1-mm: SMM 1, the sub-mm counterpart of IRAS 05327+3404, and SMM 2, ~6 arcsec to the West. The emissions of the three molecules show marked differences. The CO emission near the systemic velocity is filtered out by the telescopes, and CO mostly traces the high-velocity gas. The HCO+ and HCN emissions are more centrally concentrated around the central parts of the region, and show several intensity peaks coincident with the sub-mm continuum peaks. We identify two main molecular outflows: a bipolar outflow in an E-W direction that would be powered by SMM 1 and another one in a NE direction, which we associate with SMM 2. We propose that the SMM sources are probably Class I objects, with SMM 1 in an earlier evolutionary stage.
Revisitando o conceito de cidadania: notas para uma educa??o politécnica
Geisler, Adriana;
Trabalho, Educa??o e Saúde , 2006, DOI: 10.1590/S1981-77462006000200008
Abstract: in opposition to a community and school project which have been denying the effective citizenship to a great contingent of youth and brazilian workers, the polytechnic conception emerges as a part of an emancipating project which is far from the liberal ideology and from its reflexes on the education and work fields. retaking the issue of the citizenship meaning nowadays, this text aims to identify to which citizenship concept the polytechnic conception belongs, considering the educational practices field and its connection to the current aspect of the world of work.
Expression of a prokaryotic P-type ATPase in E. coli Plasma Membranes and Purification by Ni2+-affinity chromatography
Geisler Markus
Biological Procedures Online , 1998, DOI: 10.1251/bpo9
Abstract: In order to characterize the P-type ATPase from Synechocystis 6803 [Geisler (1993) et al. J. Mol. Biol. 234, 1284] and to facilitate its purification, we expressed an N-terminal 6xHis-tagged version of the ATPase in an ATPase deficient E. coli strain. The expressed ATPase was immunodetected as a dominant band of about 97 kDa localized to the E. coli plasma membranes representing about 20-25% of the membrane protein. The purification of the Synecho-cystis 6xHis-ATPase by single-step Ni-affinity chromatography under native and denaturating conditions is described. ATPase activity and the formation of phosphointermediates verify the full function of the enzyme: the ATPase is inhibited by vanadate (IC50= 119 &mgr;M) and the formation of phosphorylated enzyme intermediates shown by acidic PAGE depends on calcium, indicating that the Synechocystis P-ATPase functions as a calcium pump.
Josep Pla und Montaigne. Eine Skizze [Josep Pla and Montaigne. An outline]
Geisler, Eberhard
Zeitschrift für Katalanistik , 2006,
Abstract: Joseph Pla was a great admirer of French literature. As such, the writer Michel de Montaigne was of particular importance to him. Accordingly, Pla once remarked that he owed a plethora of fundamental philosophical knowledge to the author of Essais, as well as the ability to weigh and judge. In Pla’s opinion, the Frenchman was an ideal representative of a non-bombastic view of man and as a moralist. In the following passages, three further relations between the two authors will be reflected upon. To begin with, the depiction of the self and the emerging difficulty with the same phenomenon shall be treated; since the ego is not always present to itself, it vacillates between authenticity on the one hand, and convention and role on the other. Therefore the topic of the instability of human relation stands at the center of Montaigne’s observations as well as of Pla’s, which can evidently be traced in his tale “Contraban”; the theme of instability is counterbalanced by a certain consistency in these authors’ views. At last it demonstrates that both authors tend, with regard to their view of man, towards a policy of power decomposition. Thus they establish, with their understanding of nature and health, an inevitable counterimage (since Pla is defined by a profession towards antique cynicism and its use of the verb “badar”).
Wer war Joan Sales? Hinweis auf einen Autor [Who was Joan Sales? Hints on an author]
Geisler, Eberhard
Zeitschrift für Katalanistik , 2010,
Abstract: The major work of Joan Sales (1912-1983), the novel "Incerta glòria", has suffered a peculiar fate. In spite of the high praise expressed by Mercè Rodoreda in a letter to the author, the work was little acknowledged in Spain (the French translation, on the other hand, was more successful and was compared with the best novels by Bernanos). Only in recent years have critics increasingly surfaced, paying a befitting tribute to the book as a masterpiece and as a unique panorama of the Spanish Civil War and – along with the sequel "El vent de la nit" – the years of Francoism. The novel is clearly written from the view of the vanquished. This article outlines the life of Sales and demonstrates his approach of a critical, liberal and Catalan intellectual. As will be shown, the chief aim of the author is to experience and to seek the abundance of an intensive life, to create an intensity which is expressed in his literary style that is full of metaphors and, particularly, contrasts. A longer section of the article is dedicated to the vestiges of Kierkegaard in the novel. Within this it is above all the figure of the intellectual Soleràs who seems influenced by the Danish philosopher and progenitor of existentialism. The religious aspect is treated by Sales with particular tolerance. He rejects any form of power and hierarchy within religion and represents the theology of the cross, by attributing Christ as the God of the conquered. He defends a version of Catholicism which displays ecumenical traits. Of course, the classical criticism of religion (which viewed the childhood soul of the believer as a scandal) can be applied to the author, but he remains true to the spirit of the Gospel. At the end of the essay an eye is cast over poetry written by the author, in addition to his novel, and the implied attitude towards surrealism is investigated. From this a certain break with the surreal and the conception of the unconscious becomes evident. "Incerta glòria" is, by contrast, is monolithic and wholeheartedly successful. The novel encompasses the totality of the human and preaches a spirit for which any policies of exclusion are foreign.
Water Status in the Syrian Water Basins  [PDF]
Khaldoon A. Mourad, Ronny Berndtsson
Open Journal of Modern Hydrology (OJMH) , 2012, DOI: 10.4236/ojmh.2012.21003
Abstract: Syrian water resources face economic and physical water scarcity. This together with a large population and development increase and the climate change may lead to increasing risks for international controversies and disputes in the coming decades. According to FAO, the available water resource per capita AWPC is going to be half by 2025. Depending on its seven water basins, this paper analyses water demand and supply in the Syria with their projections till 2050. The paper shows that two of the seven Syrian basins need a specific concern as they face water scarcity problem. However, two basins have extra water. Therefore, the paper focuses on the need for a sustainable water management, which takes all nonconventional water resources into account to contribute in the Syrian water balance such as rainwater harvesting and wastewater reuse.
Experiences of Being Non-Smoking among Adolescents in a Smoking Context  [PDF]
Ingrid Edvardsson, Dorthe Geisler, Lena Lendahls
Health (Health) , 2014, DOI: 10.4236/health.2014.611140
Abstract: Introduction: A study among Greenlandic 13-year-old showed that 68 percent for boys and 55 percent for girls, and at age 15, 46 percent of the boys and 32 percent of the girls were non-smokers. A literature review showed that the behaviour of parents and peers, attitudes and expectations were crucial factors for the smoking habits of adolescents. Young adults would more likely start smoking if their parents, older siblings and/or friends were smokers. Parental support has been proven to be a preventive factor against smoking, especially if the school and leisure centers get involved. Group pressure, directly or indirectly, is often described as the most important reason why adolescents start smoking. The purpose was to study why some adolescents choose to be smoke-free in a society where the norm is to smoke. Methods: Adolescents who were non-smokers were interviewed in focus groups. The material was analysed using content analysis. Results: The contents analysis of the text resulted in eleven categories. Based on these, four themes were developed. These themes covered areas on the reasons for being smoke-free; how the smoke-free adolescents generally felt about smokers from a society or environment perspective, and also specifically from an individual perspective, such as how smokers took up space and did not show any consideration. There was a feeling among non-smokers of not belonging and of ambivalence, as well as a perspective of the future for adolescents in Greenland and an uncertainty about what would be required for a smoke-free environment. Conclusions: In a context where the norm is to smoke, the adolescents need to make a conscious choice to be smoke-free, and there were different reasons for this choice. This choice means becoming an outsider in their group of peers as well as the overall social culture. Smokers were seen as taking up too much space, as their needs ruled and this was deemed inconsiderate.
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