5,313 research outputs found
Thriving not just surviving: A review of research on teacher resilience
Retaining teachers in the early stages of the profession is a major issue of concern in many countries. Teacher resilience is a relatively recent area of investigation which provides a way of understanding what enables teachers to persist in the face of challenges and offers a complementary perspective to studies of stress, burnout and attrition. We have known for many years that teaching can be stressful, particularly for new teachers, but little appears to have changed. This paper reviews recent empirical studies related to the resilience of early career teachers. Resilience is shown to be the outcome of a dynamic relationship between individual risk and protective factors. Individual attributes such as altruistic motives and high self-efficacy are key individual protective factors. Contextual challenges or risk factors and contextual supports or protective factors can come from sources such as school administration, colleagues, and pupils. Challenges for the future are to refine conceptualisations of teacher resilience and to develop and examine interventions in multiple contexts. There are many opportunities for those who prepare, employ and work with prospective and new teachers to reduce risk factors and enhance protective factors and so enable new teachers to thrive, not just survive
Spontaneous curvature cancellation in forced thin sheets
In this paper we report numerically observed spontaneous vanishing of mean
curvature on a developable cone made by pushing a thin elastic sheet into a
circular container. We show that this feature is independent of thickness of
the sheet, the supporting radius and the amount of deflection. Several variants
of developable cone are studied to examine the necessary conditions that lead
to the vanishing of mean curvature. It is found that the presence of
appropriate amount of radial stress is necessary. The developable cone geometry
somehow produces the right amount of radial stress to induce just enough radial
curvature to cancel the conical azimuthal curvature. In addition, the circular
symmetry of supporting container edge plays an important role. With an
elliptical supporting edge, the radial curvature overcompensates the azimuthal
curvature near the minor axis and undercompensates near the major axis. Our
numerical finding is verified by a crude experiment using a reflective plastic
sheet. We expect this finding to have broad importance in describing the
general geometrical properties of forced crumpling of thin sheets.Comment: 13 pages, 12 figures, revtex
The Casimir force on a surface with shallow nanoscale corrugations: Geometry and finite conductivity effects
We measure the Casimir force between a gold sphere and a silicon plate with
nanoscale, rectangular corrugations with depth comparable to the separation
between the surfaces. In the proximity force approximation (PFA), both the top
and bottom surfaces of the corrugations contribute to the force, leading to a
distance dependence that is distinct from a flat surface. The measured Casimir
force is found to deviate from the PFA by up to 15%, in good agreement with
calculations based on scattering theory that includes both geometry effects and
the optical properties of the material
âStill living with it even though itâs goneâ: Using Interpretive Phenomenological Analysis to explore shared experiences of living with and beyond breast, prostate, and colorectal cancer
Purpose: Living with and beyond cancer is an increasingly common experience. While research is uncovering valuable individual experiences of those living with and beyond cancer, it has been argued that this idiographic approach is limited in outlook, reach and impact. This study contributes to the understanding of what it means to live with and beyond cancer by complementing idiographic knowledge with multiple perspectives from a group of participants who are living with and beyond cancer, to explore how individual experiences may be relevant to others. Method: Semi-structured interviews were conducted with people who had received treatment for breast (n = 6), prostate (n = 6) or colorectal cancer (n = 6). Data were analysed using interpretive phenomenological analysis. The early findings were then shared with a wider group of people who had received treatment for breast, prostate or colorectal cancer (n = 26) in six focus groups, to explore whether they had similar experiences. Results: While individual accounts of living with and beyond cancer detail unique features specific to each person's experience, focus group discussions illustrated how participant life worlds interact and overlap. The findings identified thematic similarities within and between individual and group levels and across cancer types. Three super-ordinate themes describe the shared experience of living with and beyond cancer: i) the cancer shock, ii) managing cancer and getting through and iii) getting over cancer. Conclusions: A multiple perspective approach informs our understanding of shared experiences of living with and beyond cancer. This knowledge can be used to direct, design, and deliver relevant supportive cancer care
Quantum entanglement between a nonlinear nanomechanical resonator and a microwave field
We consider a theoretical model for a nonlinear nanomechanical resonator
coupled to a superconducting microwave resonator. The nanomechanical resonator
is driven parametrically at twice its resonance frequency, while the
superconducting microwave resonator is driven with two tones that differ in
frequency by an amount equal to the parametric driving frequency. We show that
the semi-classical approximation of this system has an interesting fixed point
bifurcation structure. In the semi-classical dynamics a transition from stable
fixed points to limit cycles is observed as one moves from positive to negative
detuning. We show that signatures of this bifurcation structure are also
present in the full dissipative quantum system and further show that it leads
to mixed state entanglement between the nanomechanical resonator and the
microwave cavity in the dissipative quantum system that is a maximum close to
the semi-classical bifurcation. Quantum signatures of the semi-classical
limit-cycles are presented.Comment: 36 pages, 18 figure
Neutron, electron and X-ray scattering investigation of Cr1-xVx near Quantum Criticality
The weakness of electron-electron correlations in the itinerant
antiferromagnet Cr doped with V has long been considered the reason that
neither new collective electronic states or even non Fermi liquid behaviour are
observed when antiferromagnetism in CrV is suppressed to zero
temperature. We present the results of neutron and electron diffraction
measurements of several lightly doped single crystals of CrV in
which the archtypal spin density wave instability is progressively suppressed
as the V content increases, freeing the nesting-prone Fermi surface for a new
striped charge instability that occurs at x=0.037. This novel nesting
driven instability relieves the entropy accumulation associated with the
suppression of the spin density wave and avoids the formation of a quantum
critical point by stabilising a new type of charge order at temperatures in
excess of 400 K. Restructuring of the Fermi surface near quantum critical
points is a feature found in materials as diverse as heavy fermions, high
temperature copper oxide superconductors and now even elemental metals such as
Cr.Comment: 6 pages, 6 figures. Accepted to Physical Review
Optimal strategies for a game on amenable semigroups
The semigroup game is a two-person zero-sum game defined on a semigroup S as
follows: Players 1 and 2 choose elements x and y in S, respectively, and player
1 receives a payoff f(xy) defined by a function f from S to [-1,1]. If the
semigroup is amenable in the sense of Day and von Neumann, one can extend the
set of classical strategies, namely countably additive probability measures on
S, to include some finitely additive measures in a natural way. This extended
game has a value and the players have optimal strategies. This theorem extends
previous results for the multiplication game on a compact group or on the
positive integers with a specific payoff. We also prove that the procedure of
extending the set of allowed strategies preserves classical solutions: if a
semigroup game has a classical solution, this solution solves also the extended
game.Comment: 17 pages. To appear in International Journal of Game Theor
Mammals of Fort A. P. Hill, Caroline County, Virginia and Vicinity
Fort A.P. Hill (APH) is a 30,329 ha military training installation (U.S. Army) located in the upper Coastal Plain of Caroline County, Virginia. It was formed in 1941 and named in honor of Civil War Confederate Lt. General Ambrose Powell Hill. The current landscape includes a mosaic of habitats that range from old fields to hardwood forests. Forty species of mammals are known to exist on or near the installation. These include one marsupial, five insectivores, 9 chiropterans, one lagomorph, 12 rodents, 10 carnivores, and one cervid. We have studied many of the species on APH since 1997. In this paper we describe the physical environment of the area and 7 important habitats used by mammals. We also summarize the ecology and natural history of each species and provide statistical summaries of original measurements from mammals caught on the installation. The results of several recent studies on APH allow us to describe habitat affiliations and relative abundance of most of the mammals native to the mid-Atlantic region. Old fields and clearcuts support a total of 20 species, including several found predominately in this habitat. Pine stands and pine plantations support the fewest number of mammal species (17) of any habitat on the installation. Mixed pine and hardwood forests, hardwood forests, and riparian forests support the largest number of species (29-36). With the possible exception of pine plantations, the habitat mosaic found on APH provides abundant resources for mammal communities. We also include an evaluation of age and health attributes of the deer population and describe the hunting program on the base. Number of deer harvested annually 1985-2000 varied from 460 to 1765. Management activities since 1996 when the deer population exceeded carrying capacity have improved herd health. Because much of Caroline County and eastern Virginia is in extensive agriculture and the remaining hardwood forests are being clearcut, APH is becoming a valuable habitat island for the mammalian fauna of the upper Coastal Plain of Virginia and the mid-Atlantic region
Rim curvature anomaly in thin conical sheets revisited
This paper revisits one of the puzzling behaviors in a developable cone
(d-cone), the shape obtained by pushing a thin sheet into a circular container
of radius by a distance [E. Cerda, S. Chaieb, F. Melo, and L.
Mahadevan, {\sl Nature} {\bf 401}, 46 (1999)]. The mean curvature was reported
to vanish at the rim where the d-cone is supported [T. Liang and T. A. Witten,
{\sl Phys. Rev. E} {\bf 73}, 046604 (2006)]. We investigate the ratio of the
two principal curvatures versus sheet thickness over a wider dynamic range
than was used previously, holding and fixed. Instead of tending
towards 1 as suggested by previous work, the ratio scales as .
Thus the mean curvature does not vanish for very thin sheets as previously
claimed. Moreover, we find that the normalized rim profile of radial curvature
in a d-cone is identical to that in a "c-cone" which is made by pushing a
regular cone into a circular container. In both c-cones and d-cones, the ratio
of the principal curvatures at the rim scales as ,
where is the pushing force and is the Young's modulus. Scaling
arguments and analytical solutions confirm the numerical results.Comment: 25 pages, 12 figures. Added references. Corrected typos. Results
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