11,039 research outputs found
The Role of Learning Experiences in the Development of Expertise
This study examined the types of learning experiences leading to the development of expertise. A qualitative research approach was employed with twelve participants from a purposeful sampling of four historically themed museums. Analysis revealed learning experiences leading to expertise development included formal training and continuing education and informal and incidental learning
Rotational velocities of A-type stars II. Measurement of vsini in the northern hemisphere
This work is the second part of the set of measurements of vsini for A-type
stars, begun by Royer et al. (2002). Spectra of 249 B8 to F2-type stars
brighter than V=7 have been collected at Observatoire de Haute-Provence (OHP).
Fourier transforms of several line profiles in the range 4200--4600 A are used
to derive vsini from the frequency of the first zero. Statistical analysis of
the sample indicates that measurement error mainly depends on vsini and this
relative error of the rotational velocity is found to be about 5% on average.
The systematic shift with respect to standard values from Slettebak et al.
(1975), previously found in the first paper, is here confirmed. Comparisons
with data from the literature agree with our findings: vsini values from
Slettebak et al. are underestimated and the relation between both scales
follows a linear law: vsini(new) = 1.03 vsini(old) + 7.7. Finally, these data
are combined with those from the previous paper (Royer et al. 2002), together
with the catalogue of Abt & Morrell (1995). The resulting sample includes some
2150 stars with homogenized rotational velocities.Comment: 16 pages, includes 13 figures, accepted in A&
Do As I Say, Not As I Do: A Case Study of Two Museum Docent Training Programs
Abstract: This comparative case study examined docent training programs, at a history museum and art gallery. Data were collected through interviews with museum educators, training and promotional materials, and observations of training. Analysis revealed that the learning theory docents are encouraged to use with visitors is not applied by museum educators during docent training
How Do Museums Fit into our Notions of Adult Education?
In order to offer successful learning opportunities for adults throughout their lives it is important to explore the role of museums in adult education and learning. The goal of this roundtable is to address the long held notion that museums are valid places of adult learning and call attention to its diminished presence in adult education research and discourse
Cooperative ordering of gapped and gapless spin networks in CuFeGeO
The unusual magnetic properties of a novel low-dimensional quantum
ferrimagnet CuFeGeO are studied using bulk methods, neutron
diffraction and inelastic neutron scattering. It is shown that this material
can be described in terms of two low-dimensional quantum spin subsystems, one
gapped and the other gapless, characterized by two distinct energy scales.
Long-range magnetic ordering observed at low temperatures is a cooperative
phenomenon caused by weak coupling of these two spin networks.Comment: 4 pages, 4 figure
Investigação sobre a capacidade de sobrevivência durante o inverno na ilha Terceira, Açores, de Istocheta aldrichi (Mesnil) (Diptera: Tachinidae) um parasitóide de Popillia japonica Newman (Coleoptera: Scarabaeidae).
A study of diapause in the parasitic fly Istocheta aldrichi (Diptera: Tachinidae) was
undertaken to help investigate the possibility of its establishment in Terceira as a biological control agent of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae). It was
concluded that pupae should be imported from the USA only when they are almost ready to
emerge, and to optimise rearing conditions there to increase emergence percentages. Conditions are not ideal for its development in Terceira, as this univoltine parasitoid has a high pupal mortality both in laboratory cultures and outdoors during the overwintering period. These studies should continue until I. aldrichi has become established in the Azores
Raman scattering through surfaces having biaxial symmetry
Magnetic Raman scattering in two-leg spin ladder materials and the
relationship between the anisotropic exchange integrals are analyzed by P. J.
Freitas and R. R. P. Singh in Phys. Rev. B, {\bf 62}, 14113 (2000). The angular
dependence of the two-magnon scattering is shown to provide information for the
magnetic anisotropy in the Sr_14Cu_24O_41 and La_6Ca_8Cu_24O_41 compounds. We
point out that the experimental results of polarized Raman measurements at
arbitrary angles with respect to the crystal axes have to be corrected for the
light ellipticity induced inside the optically anisotropic crystals. We refer
quantitatively to the case of Sr_14Cu_24O_41 and discuss potential implications
for spectroscopic studies in other materials with strong anisotropy.Comment: To be published as a Comment in Phys. Rev.
Longitudinal and Transverse Zeeman Ladders in the Ising-Like Chain Antiferromagnet BaCo2V2O8
We explore the spin dynamics emerging from the N\'eel phase of the chain
compound antiferromagnet BaCo2V2O8. Our inelastic neutron scattering study
reveals unconventional discrete spin excitations, so called Zeeman ladders,
understood in terms of spinon confinement, due to the interchain attractive
linear potential. These excitations consist in two interlaced series of modes,
respectively with transverse and longitudinal polarization. The latter have no
classical counterpart and are related to the zero-point fluctuations that
weaken the ordered moment in weakly coupled quantum chains. Our analysis
reveals that BaCo2V2O8, with moderate Ising anisotropy and sizable interchain
interactions, remarkably fulfills the conditions necessary for the observation
of these longitudinal excitations.Comment: 5 pages, 4 figures, 2 additional pages of supplemental material with
2 figures; Journal ref. added; 1 page erratum added at the end with 1 figur
No Margin for Error: A Study of Two Women Balancing Motherhood and Ph.D. Studies
This cogenerative ethnography explored the lived experiences of two graduate students balancing Ph.D. studies and motherhood through McClusky’s (1963) Theory of Margi n. Specifically, we asked ourselves: What impact does pregnancy have on personal and academic selves and how are multiple roles and responsibilities managed? Through an analysis of dialogues, artifacts, conceptual maps, and narratives, examples of internal and external lo ad revealed the dynamic nature of the female experiences in graduate school. Excerpts from the data showed how roles, relationships, and experiences are characterized and how similar or different those example s were, given individual context. Implications of this research for students, faculty, and higher education policy are explored
Mesoscopic correlations in Tb2Ti2O7 spin liquid
We have studied the spin correlations with = (, ,
) propagation vector which appear below 0.4\, K in \tbti\ spin liquid
by combining powder neutron diffraction and specific heat on
TbTiO samples with =0, 0.01, -0.01. The =
(, , ) order clearly appears on all neutron patterns
by subtracting a pattern at 1.2(1)\,K. Refining the subtracted patterns at
0.07\,K yields two possible spin structures, with spin-ice-like and
monopole-like correlations respectively. Mesoscopic correlations involve Tb
moments of 1 to 2 \mub\ ordered on a length scale of about 20 \AA. In addition,
long range order involving a small spin component of 0.1 to 0.2 \mub\ is
detected for the = 0 and 0.01 samples showing a peak in the specific heat.
Comparison with previous single crystals data suggests that the (,
, ) order settles in through nanometric spin textures with
dominant spin ice character and correlated orientations, analogous to
nanomagnetic twins
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