19,343 research outputs found
Portrait of Ray O. Wolf
No full textA portrait of Ray O. Wolf, a Pacific University graduate who became a coach for Washington High school in 1930.[back] Ray O. Wolf. Class of 1926. Coach, Fall '30, at Washington High School, Portland, Orego
Oral History Interview: Richard Wolf (1397)
No full textIn his 2014 interview with Harv Thompson, Maryo Gard Ewell, and Karen Goeschko, professor emeritus of UW-Madison Extension Richard 'Dick' Wolf details his childhood and early experiences with music. Wolf chronicles his education and career at UW-Madison, with particular attention to the musicians and band directors who most influenced him, including Ray Dvorak and Emmett Sarig. Wolf also discusses Robert Gard's impact on the department. This interview was conducted for inclusion into the UW-Madison Oral History Program.
Key words: Dick Wolf; music; band; University of Wisconsin-Extension; Robert Gard; Raymond Dvorak; Emmett Sarig; School of Music, marching band; Wisconsin Youth Symphony Orchestra; Edgewood High School; Wisconsin Center for Music Educatio
[Letter from Alex Bradford to Lieutenant and Mrs. Ray Starner - November 4, 1940]
No full textLetter from Alex Bradford to Lieutenant and Mrs. Ray Starner describing the the current state of affairs that the author was experiencing, including: the London blitz, the moral of the troops on the ground, and the collective company of men opposing the Nazi regime
Gamma-Ray Bursts from tidally spun-up Wolf-Rayet stars?
No full textThe collapsar model requires rapidly rotating Wolf-Rayet stars as progenitors of long gamma-ray bursts. However, Galactic Wolf-Rayet stars rapidly lose angular momentum due to their intense stellar winds. We investigate whether the tidal interaction of a Wolf-Rayet star with a compact object in a binary system can spin up the Wolf-Rayet star enough to produce a collapsar. We compute the evolution of close Wolf-Rayet binaries, including tidal angular momentum exchange, differential rotation of the Wolf-Rayet star, internal magnetic fields, stellar wind mass loss, and mass transfer. The Wolf-Rayet companion is approximated as a point mass. We then employ a population synthesis code to infer the occurrence rates of the various relevant binary evolution channels. We find that the simple scenario -- i.e., the Wolf-Rayet star being tidally spun up and producing a collapsar -- does not occur at solar metallicity and may only occur with low probability at low metallicity. It is limited by the widening of the binary orbit induced by the strong Wolf-Rayet wind or by the radius evolution of the Wolf-Rayet star that most often leads to a binary merger. The tidal effects enhance the merger rate of Wolf-Rayet stars with black holes such that it becomes comparable to the occurrence rate of long gamma-ray bursts
Die Anwendung von Mikrosatelliten zum Studium der Sozialstruktur bei Großsäugetieren : am Beispiel von italienischem Wolf und Damwild
No full textScandura M. The use of microsatellites in the study of social structure in large mammals : Italian wolf and fallow deer as case studies. Bielefeld (Germany): Bielefeld University; 2004.The content of the present PhD thesis deals with the application of microsatellite analysis to the study of two species of large mammals, referring to some aspects of their social and mating systems. The Italian wolf (Canis lupus) and the fallow deer (Dama dama) were chosen as case studies, since genetic investigations on their populations result, for different reasons, problematic.
The wolf in Italy is a particularly protected species, recovering throughout the peninsula from the effects of a recent bottleneck. Sampling wolves may not rely on capturing or killing them, therefore an alternative, non-invasive, approach was adopted in my study. Scats, shed hairs and blood drops collected on the snow represented the main source of DNA for the analysis. Methodological cares were necessary to obtain reliable wolf genotypes. A set of ten canine microsatellites was employed to achieve unique multilocus genotypes in the population. Fifty-two individuals were typed in the period 1998 - 2003. In some cases, pack composition was determined, confirming that familiar bonds are at the basis of wolf social units. An unpredictable high local differentiation was found among geographic areas. Early dispersal seem to be common in the population, but its effects on the gene flow are not detectable, at least at my study scale. I proposed that most of this dispersal may be unsuccessful or over long distances. The study population, indeed, seem to have reached a high level of local saturation, with clumped pack territories and high reproductive rates, and thus possibly represents a source, from which wolves disperse toward sink areas.
The second study involves an enclosed population of fallow deer. Lekking is seldom observed in mammals, and among them, it is more common in ungulate species. Fallow deer is one of the most studied lekking ungulate and this particular population is object of long-term researches on male mating strategies. Mature bucks in the population join into leks during the breeding season: a costly strategy, which apparently does not guarantee high direct benefits (fitness). In this study, for the first time, I used a molecular approach to verify the existence of a genetic basis to lek formation. The recourse to microsatellites enabled to overcome the strong limitation due to the extremely monomorphism of the species, documented in several studies. Though the low variability even at microsatellite loci, the hypotheses of kin selection (territorial bucks in a lek are relatives) and of heterozygosity advantage (territorial bucks in a lek have an overall high heterozygosity) were tested and resulted not supported by data. Hence, future studies should be addressed towards phenotypic variation and consider in detail physiological and ecological factors, in order to clarify the reasons why lekking takes place in fallow deer
The student's guide to completing an author study
No full textThe 'Student's guide to completing an author study' emerged during the early development of the school library resource center program at Glen Stewart Elementary School in Stratford Canada on Prince Edward Island. This research process centered on an author study, with direct teaching and clear assignment. The resulting model has been adapted to various grade levels and subject areas in different schools.Source type: Electronic(1)http://proquest.umi.com/pqdweb?did=49237063&Fmt=7&clientId=65345&RQT=309&VName=PQ
Active X-ray optics for the next generation of X-ray space telescopes
No full textDescribed within is the design, manufacture, metrology and X-ray testing of an active X-ray
prototype intended for the next generation of X-ray telescopes. One of the challenges faced by
the X-ray telescope community is how to combine high resolution and high sensitivity into one
system, as weight limitations place constraints on the optics that can be launched. Therefore the
mandate of the active X-ray prototype is to provide high sensitivity through the ability of the optics
to be nested and to deliver high angular resolution through the active control of the optic’s form.
Piezoelectric unimorph actuators provide the active component: it is intended that they will correct
for figure errors within the optic and therefore increase the angular resolution capability.
The prototype’s design is based upon an ellipsoidal segment which provides point-to-point
focussing of an X-ray source. The prototype itself is composed of an electroformed nickel optic
where the non-reflective surface is populated with 30 piezoelectric actuators and it is the production
of the prototype that is the core of the presented research. Metrology of the actuators’ influence
functions is presented and highlight the prototype’s ability to deform its optic surface by microns.
In addition, the measured influence functions are compared against finite element models and a
distinct similarity between the functions is observed.
The prototype was tested at an X-ray beamline facility in November 2008 and the results
showed the prototype’s ability to correct the optic to achieve an improved angular resolution: from
0.786 arc-minutes to 0.686 arc-minutes in terms of full width half maximum. Finally, difficulties
in the manufacture of the prototype and X-ray testing shall be presented alongside future work in
conclusion to this thesis
Wolf-Rayet stars as gamma-ray burst progenitors
No full textIt became clear in the last few years that long gamma-ray bursts are associated with the endpoints of massive star evolution. They occur in star forming regions at cosmological distances (Jakobsson et al., 2005), and are associated with supernova-type energies. The collapsar model explains gamma-ray burst formation via the collapse of a rapidly rotation massive iron core into a black hole (Woosley, 1993). The short time scale of gamma-ray emission requires a compact stellar size object, of the order of light seconds. This constraint leaves only massive Wolf–Rayet stars as possible progenitors. However, this poses a difficulty: Wolf–Rayet stars in the local universe are known to have strong stellar winds (Nugis et al., 1998 T. Nugis, P.A. Crowther and A.J. Willis, A&A 333 (1998), p. 956. View Record in Scopus | Cited By in Scopus (73)Nugis et al., 1998), which lead to a rapid spin-down (Langer, 1998) – in agreement with the absence of signatures of rapid rotation in the Galactic Wolf–Rayet sample. An additional obstacle for forming a rapidly rotating Wolf–Rayet star in the course of single star evolution is the shear between core and envelope generated by the former’s contraction and the latter’s expansion after the main sequence. Magnetic torques are expected to lead to a strong coupling and related core spin down ([Spruit, 2002], [Heger et al., 2005] and [Petrovic et al., 2005]). Indeed, such coupling is required to understand the slow rotation of young neutron stars (Ott et al., 2006) and white dwarfs (Berger et al., 2005). This implies that single stars which, during their evolution, become a supergiant, i.e. obtain a massive extended envelope, will not be suitable GRB progenitors, even if they end their life as Wolf–Rayet star
Wolf-Rayet stars as gamma-ray burst progenitors
No full textIt became clear in the last few years that long gamma-ray bursts are associated with the endpoints of massive star evolution. They occur in star forming regions at cosmological distances (Jakobsson et al., 2005), and are associated with supernova-type energies. The collapsar model explains gamma-ray burst formation via the collapse of a rapidly rotation massive iron core into a black hole (Woosley, 1993). The short time scale of gamma-ray emission requires a compact stellar size object, of the order of light seconds. This constraint leaves only massive Wolf–Rayet stars as possible progenitors. However, this poses a difficulty: Wolf–Rayet stars in the local universe are known to have strong stellar winds (Nugis et al., 1998 T. Nugis, P.A. Crowther and A.J. Willis, A&A 333 (1998), p. 956. View Record in Scopus | Cited By in Scopus (73)Nugis et al., 1998), which lead to a rapid spin-down (Langer, 1998) – in agreement with the absence of signatures of rapid rotation in the Galactic Wolf–Rayet sample. An additional obstacle for forming a rapidly rotating Wolf–Rayet star in the course of single star evolution is the shear between core and envelope generated by the former’s contraction and the latter’s expansion after the main sequence. Magnetic torques are expected to lead to a strong coupling and related core spin down ([Spruit, 2002], [Heger et al., 2005] and [Petrovic et al., 2005]). Indeed, such coupling is required to understand the slow rotation of young neutron stars (Ott et al., 2006) and white dwarfs (Berger et al., 2005). This implies that single stars which, during their evolution, become a supergiant, i.e. obtain a massive extended envelope, will not be suitable GRB progenitors, even if they end their life as Wolf–Rayet star
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