49,972 research outputs found
Barriers & facilitators to extended working life : a focus on a predominately female ageing workforce
Many countries are reforming their pension systems so people stay in work for longer
to improve the long-term sustainability of public finances to support an increasing older
population. This research aimed to explore the factors that enable or inhibit people to extend
working life (EWL) in a large UK based retail organisation. Semi-structured interviews were
carried out with a purposive sample (n=30): 15 employees aged ≥ 60 and 15 supervisors
supporting these employees. Older workers were predominately female, reflecting the gender
profile of the older workers in the organisation. Older workers and supervisors reported that
key facilitators to EWL were: good health, the perception that older workers are of value;
flexibility and choice; the need for an ongoing conversation across the life-course; the social
and community aspect of work as a facilitator to EWL; and, the financial necessity to EWL.
Perceived barriers to EWL included poor health, negative impacts of work on health, and a
lack of respect and support
Quasi-circular Orbits for Spinning Binary Black Holes
Using an effective potential method we examine binary black holes where the
individual holes carry spin. We trace out sequences of quasi-circular orbits
and locate the innermost stable circular orbit as a function of spin. At large
separations, the sequences of quasi-circular orbits match well with
post-Newtonian expansions, although a clear signature of the simplifying
assumption of conformal flatness is seen. The position of the ISCO is found to
be strongly dependent on the magnitude of the spin on each black hole. At close
separations of the holes, the effective potential method breaks down. In all
cases where an ISCO could be determined, we found that an apparent horizon
encompassing both holes forms for separations well inside the ISCO.
Nevertheless, we argue that the formation of a common horizon is still
associated with the breakdown of the effective potential method.Comment: 13 pages, 10 figures, submitted to PR
Effects of visual and motion simulation cueing systems on pilot performance during takeoffs with engine failures
Data are presented that show the effects of visual and motion during cueing on pilot performance during takeoffs with engine failures. Four groups of USAF pilots flew a simulated KC-135 using four different cueing systems. The most basic of these systems was of the instrument-only type. Visual scene simulation and/or motion simulation was added to produce the other systems. Learning curves, mean performance, and subjective data are examined. The results show that the addition of visual cueing results in significant improvement in pilot performance, but the combined use of visual and motion cueing results in far better performance
Teaching in the Middle Grades Today: Examining Teachers’ Beliefs About Middle Grades Teaching
Since the beginning of the middle school movement in the mid-1960s, middle level advocates have called for a school experience for young adolescents grounded in adolescent development that engages students in meaningful learning (Eichhorn, 1966; Alexander & Williams, 1965). The aim of this exploratory multi-case study was to understand middle level teachers’ beliefs about middle level instruction in the current educational environment. To gain this understanding, researchers asked ten current middle grades teachers with varying levels of experience to discuss their beliefs regarding their primary purpose as a middle grades teacher, the current status of middle level teaching, their best and worst instructional lessons, and their perceived barriers to teaching at the middle level. The teachers described the role of teaching in the middle grades as challenging and stressful, but of great importance. In general, they described instruction that included discovery, student engagement, and relevance in an effort to address students’ academic development. There was minimal mention of the non-academic aspects of adolescent development. Finally, teachers viewed curriculum restrictions, students’ attitudes toward learning, difficulty with differentiation, and lack of technology as significant barriers to their success in the classroom
Spin-orbit coupled j=1/2 iridium moments on the geometrically frustrated fcc lattice
Motivated by experiments on the double perovskites La2ZnIrO6 and La2MgIrO6,
we study the magnetism of spin-orbit coupled j=1/2 iridium moments on the
three-dimensional, geometrically frustrated, face-centered cubic lattice. The
symmetry-allowed nearest-neighbor interaction includes Heisenberg, Kitaev, and
symmetric off-diagonal exchange. A Luttinger-Tisza analysis shows a rich
variety of orders, including collinear A-type antiferromagnetism, stripe order
with moments along the [111]-direction, and incommensurate non-coplanar
spirals, and we use Monte Carlo simulations to determine their magnetic
ordering temperatures. We argue that existing thermodynamic data on these
iridates underscores the presence of a dominant Kitaev exchange, and also
suggest a resolution to the puzzle of why La2ZnIrO6 exhibits `weak'
ferromagnetism, but La2MgIrO6 does not.Comment: 5 pages, 5 figs, significantly revised to address referee comments,
to appear in PRB Rapid Com
Numerical investigation of gapped edge states in fractional quantum Hall-superconductor heterostructures
Fractional quantum Hall-superconductor heterostructures may provide a
platform towards non-abelian topological modes beyond Majoranas. However their
quantitative theoretical study remains extremely challenging. We propose and
implement a numerical setup for studying edge states of fractional quantum Hall
droplets with a superconducting instability. The fully gapped edges carry a
topological degree of freedom that can encode quantum information protected
against local perturbations. We simulate such a system numerically using exact
diagonalization by restricting the calculation to the quasihole-subspace of a
(time-reversal symmetric) bilayer fractional quantum Hall system of Laughlin
states. We show that the edge ground states are permuted by
spin-dependent flux insertion and demonstrate their fractional Josephson
effect, evidencing their topological nature and the Cooper pairing of
fractionalized quasiparticles.Comment: 12 pages, 9 figure
The two-phase approximation for black hole collisions: Is it robust?
Recently Abrahams and Cook devised a method of estimating the total radiated
energy resulting from collisions of distant black holes by applying Newtonian
evolution to the holes up to the point where a common apparent horizon forms
around the two black holes and subsequently applying Schwarzschild perturbation
techniques . Despite the crudeness of their method, their results for the case
of head-on collisions were surprisingly accurate. Here we take advantage of the
simple radiated energy formula devised in the close-slow approximation for
black hole collisions to test how strongly the Abrahams-Cook result depends on
the choice of moment when the method of evolution switches over from Newtonian
to general relativistic evolution. We find that their result is robust, not
depending strongly on this choice.Comment: 4 pages, 3 figures, submitted to Classical and Quantum Gravit
Two phase galaxy formation: The Evolutionary Properties of Galaxies
We use our model for the formation and evolution of galaxies within a
two-phase galaxy formation scenario, showing that the high-redshift domain
typically supports the growth of spheroidal systems, whereas at low redshifts
the predominant baryonic growth mechanism is quiescent and may therefore
support the growth of a disc structure. Under this framework we investigate the
evolving galaxy population by comparing key observations at both low and
high-redshifts, finding generally good agreement. By analysing the evolutionary
properties of this model, we are able to recreate several features of the
evolving galaxy population with redshift, naturally reproducing number counts
of massive star-forming galaxies at high redshifts, along with the galaxy
scaling relations, star formation rate density and evolution of the stellar
mass function. Building upon these encouraging agreements, we make model
predictions that can be tested by future observations. In particular, we
present the expected evolution to z=2 of the super-massive black hole mass
function, and we show that the gas fraction in galaxies should decrease with
increasing redshift in a mass, with more and more evolution going to higher and
higher masses. Also, the characteristic transition mass from disc to bulge
dominated system should decrease with increasing redshift.Comment: 15 pages, 11 figures. Version polished for publication in MNRA
- …