1,924 research outputs found
Climatic role of Southern Hemisphere extratropical cyclones and their relationship with sea ice
Transient atmospheric systems play a central role in determining the climate of the high southern latitudes. Accordingly, the variability of these features and the mechanisms which cause it are important considerations for the (palaeo)climatologist. One element which might have been expected to be intimately tied up with cyclonic activity is the extent of sea ice encircling the Antarctic continent.
We refer to studies which suggest relationships between sea ice and cyclones on synoptic time-scales, but in which these become very weak when interannual relationships are considered. We have analysed the reasons for this apparently contradictory behaviour. It is suggested that the intuitive appeal of an ice-cyclone connection has an implicit and characteristic time-scale (of a few hours or days) associated with it.
However, the same reasoning cannot be applied to longer periods, because of the nonlinearities in the links between the two factors. This, in particular, cautions against the use of simplistic arguments when trying to estimate the locations of storm tracks during epochs when seaicc coverage was very different from that obtaining during the insttumental record
Invoking posthumanist vistas: A diffractive gaze on curriculum practices and potential
Humanist discourse has assumed such an ideological normalcy to the extent that any attempts at its disruption are likely to be met with severe resistance. As such, higher education curriculum design and curriculum content continue to be largely anthropocentric, buoyed by human-centred neoliberal principles that have gradually encroached the academe. To explore ways out of the dilemma, we draw on wild pedagogy theory (Jickling 2015; Mcphie and Clarke 2015; Springgay and Zaliwska 2017; Jickling et al. 2018b) as a means to challenge the straitjacket constraints of neoliberal higher education. Over time, the wild has been banished from classrooms: the call for wild pedagogies might mean that we have reached the limits of the “tamed” ‒ and we have tamed a lot in order to offer a “one size fits all” approach to (higher) education (Jickling et al. 2018a). The tendency for higher education to teach more and more people in less and less time, has implied an understanding of teaching that is characterised by efficiency and processing, at the cost of the process of learning as a relational becoming with the world in the posthuman condition we live in (Braidotti 2019). In this article, vignettes are used to offer an account of our critical posthumanist incursions as university lecturers into curriculum practices. We use a diffractive gaze to present the generative potential of non-anthropocentric approaches as well as the struggles that these present as we strive to de-center our humanistic tendencies towards curriculum knowledge and teaching within the neoliberal space, we find ourselves
The Romwe Catchment Study, Zimbabwe: The effects of changing rainfall and land use on recharge to crystalline basement aquifers, and the implications for rural water supply and small-scale irrigation. Final Report
Parametric coupling between macroscopic quantum resonators
Time-dependent linear coupling between macroscopic quantum resonator modes
generates both a parametric amplification also known as a {}"squeezing
operation" and a beam splitter operation, analogous to quantum optical systems.
These operations, when applied properly, can robustly generate entanglement and
squeezing for the quantum resonator modes. Here, we present such coupling
schemes between a nanomechanical resonator and a superconducting electrical
resonator using applied microwave voltages as well as between two
superconducting lumped-element electrical resonators using a r.f.
SQUID-mediated tunable coupler. By calculating the logarithmic negativity of
the partially transposed density matrix, we quantitatively study the
entanglement generated at finite temperatures. We also show that
characterization of the nanomechanical resonator state after the quantum
operations can be achieved by detecting the electrical resonator only. Thus,
one of the electrical resonator modes can act as a probe to measure the
entanglement of the coupled systems and the degree of squeezing for the other
resonator mode.Comment: 15 pages, 4 figures, submitte
Dynamics of thermoelastic thin plates: A comparison of four theories
Four distinct theories describing the flexural motion of thermoelastic thin
plates are compared. The theories are due to Chadwick, Lagnese and Lions,
Simmonds, and Norris. Chadwick's theory requires a 3D spatial equation for the
temperature but is considered the most accurate as the others are derivable
from it by different approximations. Attention is given to the damping of
flexural waves. Analytical and quantitative comparisons indicate that the
Lagnese and Lions model with a 2D temperature equation captures the essential
features of the thermoelastic damping, but contains systematic inaccuracies.
These are attributable to the approximation for the first moment of the
temperature used in deriving the Lagnese and Lions equation. Simmonds' model
with an explicit formula for temperature in terms of plate deflection is the
simplest of all but is accurate only at low frequency, where the damping is
linearly proportional to the frequency. It is shown that the Norris model,
which is almost as simple as Simmond's, is as accurate as the more precise but
involved theory of Chadwick.Comment: 2 figures, 1 tabl
"Fortunate are those who take the first steps"? The psychosocial impact of novel drug development.
Novel drug development offers people with cystic fibrosis exciting opportunities but is not without challenges. Currently, there is an understandable emphasis on protecting patients' physical health when developing treatments. However, there appears to be little consideration of how novel drug development impacts on psychosocial wellbeing, or the downstream consequences of this. Using an illustrative case and reviewing the literature we explore themes regarding the psychosocial impact of trial participation and novel drug development and identify areas requiring further research. Through this, we hope to prepare healthcare professionals to better understand the needs of their patients in this rapidly evolving landscape
Coherent quantum state storage and transfer between two phase qubits via a resonant cavity
A network of quantum-mechanical systems showing long lived phase coherence of
its quantum states could be used for processing quantum information. As with
classical information processing, a quantum processor requires information bits
(qubits) that can be independently addressed and read out, long-term memory
elements to store arbitrary quantum states, and the ability to transfer quantum
information through a coherent communication bus accessible to a large number
of qubits. Superconducting qubits made with scalable microfabrication
techniques are a promising candidate for the realization of a large scale
quantum information processor. Although these systems have successfully passed
tests of coherent coupling for up to four qubits, communication of individual
quantum states between qubits via a quantum bus has not yet been demonstrated.
Here, we perform an experiment demonstrating the ability to coherently transfer
quantum states between two superconducting Josephson phase qubits through a
rudimentary quantum bus formed by a single, on chip, superconducting
transmission line resonant cavity of length 7 mm. After preparing an initial
quantum state with the first qubit, this quantum information is transferred and
stored as a nonclassical photon state of the resonant cavity, then retrieved at
a later time by the second qubit connected to the opposite end of the cavity.
Beyond simple communication, these results suggest that a high quality factor
superconducting cavity could also function as a long term memory element. The
basic architecture presented here is scalable, offering the possibility for the
coherent communication between a large number of superconducting qubits.Comment: 17 pages, 4 figures (to appear in Nature
Measurement crosstalk between two phase qubits coupled by a coplanar waveguide
We analyze the measurement crosstalk between two flux-biased phase qubits
coupled by a resonant coplanar waveguide cavity. After the first qubit is
measured, the superconducting phase can undergo damped oscillations resulting
in an a.c. voltage that produces a frequency chirped noise signal whose
frequency crosses that of the cavity. We show experimentally that the coplanar
waveguide cavity acts as a bandpass filter that can significantly reduce the
crosstalk signal seen by the second qubit when its frequency is far from the
cavity's resonant frequency. We present a simple classical description of the
qubit behavior that agrees well with the experimental data. These results
suggest that measurement crosstalk between superconducting phase qubits can be
reduced by use of linear or possibly nonlinear resonant cavities as coupling
elements.Comment: 4 pages, 3 figure
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