scholarly journals Frequency Analysis of the Rapidly Oscillating Ap Star HD 60435

1986 ◽  
Vol 90 ◽  
pp. 239-242
Author(s):  
Jaymie M. Matthews ◽  
Donald W. Kurtz ◽  
William H. Wehlau
Keyword(s):  
South African ◽  
Frequency Spectrum ◽  
Rotation Period ◽  
Frequency Spectra ◽  
Rapid Variability ◽  
University Of Toronto ◽  
The University ◽  
Ap Stars ◽  
Radial Pulsations ◽  
Equal Spacing

AbstractThe cool Ap star HD 60435 was monitored in a programme of rapid B photometry during 18 nights in January/February 1984, from two stations widely spaced in longitude (the University of Toronto 0.6-m telescope at the Carnegie Southern Observatory (CARSO) on Las Campanas, Chile, and the 0.5-m telescope of the South African Astronomical Observatory ( SAAO)). On six of those nights, contiguous light curves from both sites were obtained.Fourier analysis of these data confirms the rapid variability first reported by Kurtz (1984) and reveals several additional transient oscillations. HD 60435 exhibits persistent - but modulated - oscillations at a frequency near 1.4 IRHZ (period = 11.9 minutes), and short-lived oscillations at frequencies near 1.1 and 4.2 mHz (periods of 15.2 and 4.0 minutes, respectively). These latter two periods represent the longest and shortest yet observed in the class of rapidly oscillating Ap stars.We have applied the oblique pulsator model (Kurtz 1982) to the fine-scale splittings detected in the frequency spectra of the 1.4 and 1.1 mHz oscillations. Also, the series of frequencies close to 1.4 mHz which fall into a pattern of roughly equal spacing is compared to such spacings predicted for overtones in pulsating main-sequence A stars (Shibahashi and Saio 1984). Both approaches suggest that HD 60435 is undergoing non-radial pulsations of odd and even degree (probably with ℓ ≲ 3).The oblique pulsator interpretation of the splittings in the frequency spectrum and the amplitude modulation of the 1.4 mHz oscillations also predict: a rotation period of approximately eight days for this star. Mean photometry of HD 60435, collected by the authors, supports a similar value of 7.7 days for the period.Analysis of the oscillations is hampered by ambiguities due to daily aliases present in the data, and by the complicated structure and time-dependence of the frequency spectrum. Further observations of HD 60435 are essential if we are to fully understand its rapid variations.

scholarly journals Multiple, short-lived “stellar prominences” on O stars: the supergiant λ Cephei

2014 ◽  
Vol 9 (S307) ◽  
pp. 379-380
Author(s):  
H. F. Henrichs ◽  
N. Sudnik
Keyword(s):  
Magnetic Fields ◽  
Rotation Period ◽  
Life Time ◽  
Simplified Model ◽  
Common Phenomenon ◽  
Rapid Variability ◽  
Time Resolved ◽  
Ob Stars ◽  
Cyclical Variability ◽  
Radial Pulsations

AbstractMany OB stars show unexplained cyclical variability in their winds and in many optical lines, which are formed at the base of the wind. For these stars no dipolar magnetic fields have been detected. We propose that these cyclical variations are caused by the presence of multiple, transient, short-lived, corotating magnetic loops, which we call “stellar prominences”. We present a simplified model representing these prominences as corotating spherical blobs and fit the rapid variability in the Heiiλ4686 line of the O supergiant λ Cep for time-resolved spectra obtained in 1989. Our conclusions are: (1) From model fits we find that the life time of the prominences varies, and is between 2–7 h. (2) The adopted inclination angle is 68° with a rotation period of ≈ 4.1 d (but not well constrained). (3) The contribution of non-radial pulsations is negligible (4) Similar behavior is observed in at least 4 other O stars. We propose that prominences are a common phenomenon among O stars.

scholarly journals Spectral Variations of the Rapidly Oscillating Ap Star HD 60435

1985 ◽  
Vol 87 ◽  
pp. 313-319
Author(s):  
J.M. Matthews ◽  
R.W. Slawson ◽  
W.H. Wehlau
Keyword(s):  
Maximum Amplitude ◽  
University Of Toronto ◽  
The University ◽  
Magnetic Poles ◽  
Ap Stars ◽  
Low Amplitude

AbstractThe peculiar F star HD 60435 exhibits broadband light oscillations of low amplitude with periods between 15 and 4 minutes. Photographic spectra obtained in January/February 1985 using the University of Toronto 0.6 m telescope on Las Campanas, Chile, reveal that the star also undergoes slow spectral variations like those observed in many Ap stars. The data further suggest that Sr II maximum may coincide with maximum amplitude of light oscillations. According to the oblique pulsator model (Kurtz 1982) for such variables, this implies that Sr II is concentrated near at least one of the magnetic poles of HD 60435.

Development of the University of Toronto Skull Base Inventory (UT-SBI) Quality-of-Life Questionnaire

Skull Base ◽  
2009 ◽  
Vol 19 (03) ◽  
Author(s):  
John de Almeida ◽  
Allan Vescan ◽  
Jolie Ringash ◽  
Patrick Gullane ◽  
Fred Gentili ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Skull Base ◽  
Life Questionnaire ◽  
Quality Of Life Questionnaire ◽  
University Of Toronto ◽  
The University

Disruptive innovation and operationalization in local and sustainable food systems: Examining the University of Toronto-Local Food Plus partnership

2019 ◽  
Vol 6 (1) ◽  
pp. 120-139
Author(s):  
Lori Stahlbrand
Keyword(s):  
Food Systems ◽  
Large Scale ◽  
Food System ◽  
Local Food ◽  
Disruptive Innovation ◽  
Government Support ◽  
Sustainable Food ◽  
University Of Toronto ◽  
The University

This paper traces the partnership between the University of Toronto and the non-profit Local Food Plus (LFP) to bring local sustainable food to its St. George campus. At its launch, the partnership represented the largest purchase of local sustainable food at a Canadian university, as well as LFP’s first foray into supporting institutional procurement of local sustainable food. LFP was founded in 2005 with a vision to foster sustainable local food economies. To this end, LFP developed a certification system and a marketing program that matched certified farmers and processors to buyers. LFP emphasized large-scale purchases by public institutions. Using information from in-depth semi-structured key informant interviews, this paper argues that the LFP project was a disruptive innovation that posed a challenge to many dimensions of the established food system. The LFP case study reveals structural obstacles to operationalizing a local and sustainable food system. These include a lack of mid-sized infrastructure serving local farmers, the domination of a rebate system of purchasing controlled by an oligopolistic foodservice sector, and embedded government support of export agriculture. This case study is an example of praxis, as the author was the founder of LFP, as well as an academic researcher and analyst.

Buddhist, a Christian, and an Atheist Walk into a Classroom

2013 ◽  
Vol 42 (3) ◽  
pp. 37-42
Author(s):  
Ken Derry
Keyword(s):  
First Year ◽  
Specific Relation ◽  
University Of Toronto ◽  
Central Focus ◽  
The University

Although none of the articles in this issue on the topic of religion and humor are explicitly about teaching, in many ways all of them in fact share this central focus. In the examples discussed by the four authors, humor is used to deconstruct the category of religion; to comment on the distance between orthodoxy and praxis; to censure religion; and to enrich traditions in ways that can be quite self-critical. My response to these articles addresses each of the above lessons in specific relation to experiences I have had in, and strategies I have developed for, teaching a first-year introductory religion course at the University of Toronto.

63. Developing a program for resident wellness at the postgraduate medical education office, University of Torontos

2007 ◽  
Vol 30 (4) ◽  
pp. 63 ◽  
Author(s):  
S. Edwards ◽  
S. Verma ◽  
R. Zulla
Keyword(s):  
Mental Health ◽  
Medical Education ◽  
Stress Management ◽  
Residency Training ◽  
Medical Training ◽  
Postgraduate Medical Education ◽  
Program Directors ◽  
University Of Toronto ◽  
Resident Wellness ◽  
The University

Prevalence of stress-related mental health problems in residents is equal to, or greater than, the general population. Medical training has been identified as the most significant negative influence on resident mental health. At the same time, residents possess inadequate stress management and general wellness skills and poor help-seeking behaviours. Unique barriers prevent residents from self-identifying and seeking assistance. Stress management programs in medical education have been shown to decrease subjective distress and increase wellness and coping skills. The University of Toronto operates the largest postgraduate medical training program in the country. The Director of Resident Wellness position was created in the Postgraduate Medical Education Office to develop a systemic approach to resident wellness that facilitates early detection and intervention of significant stress related problems and promote professionalism. Phase One of this new initiative has been to highlight its presence to residents and program directors by speaking to resident wellness issues at educational events. Resources on stress management, professional services, mental health, and financial management have been identified and posted on the postgraduate medical education website and circulated to program directors. Partnerships have been established with physician health professionals, the University of Toronto, and the Professional Association of Residents and Internes of Ontario. Research opportunities for determining prevalence and effective management strategies for stress related problems are being identified and ultimately programs/resources will be implemented to ensure that resident have readily accessible resources. The establishment of a Resident Wellness Strategy from its embryonic stags and the challenges faced are presented as a template for implementing similar programs at other medical schools. Earle L, Kelly L. Coping Strategies, Depression and Anxiety among Ontario Family Medicine Residents. Canadian Family Physician 2005; 51:242-3. Cohen J, Patten S. Well-being in residency training: a survey examining resident physician satisfaction both within and outside of residency training and mental health in Alberta. BMC Medical Education; 5(21). Levey RE. Sources of stress for residents and recommendations for programs to assist them. Academic Med 2001; 70(2):142-150.

ROLE OF LIBRARIANS IN TEACHING INFORMATION LITERACY IN ZIMBABWEAN AND SOUTH AFRICAN UNIVERSITIES: A COMPARATIVE STUDY

Mousaion ◽  
2016 ◽  
Vol 33 (1) ◽  
pp. 23-42 ◽  
Author(s):  
Tinashe Mugwisi
Keyword(s):  
South Africa ◽  
South African ◽  
Information Literacy ◽  
Ethical Issues ◽  
University Libraries ◽  
Information And Communications Technologies ◽  
Communications Technologies ◽  
Information Skills ◽  
The University

Information and communications technologies (ICTs) and the Internet have to a large extent influenced the way information is made available, published and accessed. More information is being produced too frequently and information users now require certain skills to sift through this multitude in order to identify what is appropriate for their purposes. Computer and information skills have become a necessity for all academic programmes. As libraries subscribe to databases and other peer-reviewed content (print and electronic), it is important that users are also made aware of such sources and their importance. The purpose of this study was to examine the teaching of information literacy (IL) in universities in Zimbabwe and South Africa, and the role played by librarians in creating information literate graduates. This was done by examining whether such IL programmes were prioritised, their content and how frequently they were reviewed. An electronic questionnaire was distributed to 12 university libraries in Zimbabwe and 21 in South Africa. A total of 25 questionnaires were returned. The findings revealed that IL was being taught in universities library and non-library staff, was compulsory and contributed to the term mark in some institutions. The study also revealed that 44 per cent of the total respondents indicated that the libraries were collaborating with departments and faculty in implementing IL programmes in universities. The study recommends that IL should be an integral part of the university programmes in order to promote the use of databases and to guide students on ethical issues of information use.

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