98 research outputs found
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Entropy and uncertainty
No full textWe give a survey of the basic statistical ideas underlying the definition of entropy in
information theory and their connections with the entropy in the theory of dynamical systems
and in statistical mechanics
The Prime Ministerial Task Group on Emissions Trading: an assessment
No full textThe final report by the Prime Ministerial Task Group on Emissions Trading is
a critical turning point in the climate debate in Australia. This report is
particularly important for a number of reasons. First, it offers a strategy for
climate policy in Australia that moves away from the recent approach of specific
subsidies for technology to reduce emissions, and towards a policy of pricing
greenhouse-gas emissions so that all greenhouse-gas-reducing technologies are
encouraged. More importantly, the Task Group approach offers a new framework
for global climate policy to move beyond the approach followed in the Kyoto
Protocol
Inside-out electromagnetic cloaking
No full textWe introduce a novel concept of an inside-out (or inverse)
cloak for electromagnetic waves based on the coordinate transformation of
Maxwell’s equations. This concept can be employed for creating absorbing
non-reflecting media as matching layers in numerical simulations. In
contrast to the commonly used perfectly matched layers, such absorbing
boundaries are characterized by physically meaningful parameters, and the
concept can be used in various numerical simulation schemes
Spatially engineered polarization states and optical vortices in uniaxial crystals
No full textWe describe how the propagation of light through uniaxial
crystals can be used as a versatile tool towards the spatial engineering
of polarization and phase, thereby providing an all-optical technique for
vectorial and scalar singular beam shaping in optics. Besides the prominent
role played by the linear birefringence, the influence of circular birefringence
(the optical activity) is discussed as well and both the monochromatic
and polychromatic singular beam shaping strategies are addressed. Under
cylindrically symmetric light-matter interaction, the radially, azimuthally,
and spirally polarized eigen-modes for the light field are revealed to be of
a fundamental interest to describe the physical mechanisms at work when
dealing with scalar and vectorial optical singularities. In addition, we also
report on nontrivial effects arising from cylindrical symmetry breaking, e.g.
tilting the incident beam with respect to the crystal optical axis
Soliton as strange attractor: nonlinear synchronization and chaos
No full textWe show that dissipative solitons can have dynamics similar to that of a strange attractor in low-dimensional systems. Using a model of a passively mode-locked fiber laser as an example, we show that soliton pulsations with periods equal to several round-trips of the cavity can be chaotic, even though they are synchronized with the round-trip time. The chaotic part of this motion is quantified using a two-dimensional map and estimating the Lyapunov exponent. We found a specific route to chaotic motion that occurs through the creation, increase, and overlap of “islands” of chaos rather than through multiplication of frequencies
The genesis of the civilian
No full textThis paper argues that the concept of the civilian is a specific way of viewing non-combatants that can be traced to the First World War. Before the war, non-combatants were seen by the law and the prevailing culture as citizens. The citizen was potentially and probably aggressive, bound to the fate of his or her state and, therefore, granted only minimal protection by law. The war, however, brought technological changes and a propaganda effort that transformed these citizens into a civilian population. Civilians were essential to the war effort, which meant that they were a target. Yet, at the same time, they were feminized, described as vulnerable and deserving of protection. This cultural shift influenced the way in which the laws of war were understood, leading to the replacement of the traditional categories of law with a military/civilian distinction in the 1923 Hague Draft Rules of Aerial Warfare. In this way the concept of the civilian entered international law
Study protocol: a randomised controlled trial of multiple and single dose activated charcoal for acute self-poisoning
No full textBACKGROUND:
The case fatality for intentional self-poisoning in rural Asia is 10–30 times higher than in the West, mostly due to the use of highly toxic poisons. Activated charcoal is a widely available intervention that may – if given early – bind to poisons in the stomach and prevent their absorption. Current guidelines recommend giving a single dose of charcoal (SDAC) if patients arrive within an hour of ingestion. Multiple doses (MDAC) may increase poison elimination at a later time by interrupting any enterohepatic or enterovascular circulations. The effectiveness of SDAC or MDAC is unknown. Since most patients present to hospital after one hour, we considered MDAC to have a higher likelihood of clinical benefit and set up a study to compare MDAC with no charcoal. A third arm of SDAC was added to help determine whether any benefit noted from MDAC resulted from the first dose or all doses.
METHODS/DESIGN:
We set up a randomised controlled trial assessing the effectiveness of superactivated charcoal in unselected adult self-poisoning patients admitted to the adult medical wards of three Sri Lankan secondary hospitals. Patients were randomised to standard treatment or standard treatment plus either a single 50 g dose of superactivated charcoal dissolved in 300 ml of water or six doses every four hours. All patients with a history of poison ingestion were approached concerning the study and written informed consent taken from each patient, or their relative (for unconscious patients or those 72 hrs post-ingestion, and previous recruitment. The primary outcome was in-hospital mortality; secondary outcomes included the occurrence of serious complications (need for intubation, time requiring assisted ventilation, fits, cardiac dysrhythmias). Analysis will be on an intention-to-treat basis; the effects of reported time to treatment after poisoning and status on admission will also be assessed.
DISCUSSION:
This trial will provide important information on the effectiveness of both single and multiple dose activated charcoal in the forms of poisoning commonly seen in rural Asia. If charcoal is found to be effective, it should be possible to make it widely available across rural Asia in an affordable formulation.
TRIAL REGISTRATION:
Current Controlled Trials ISRCTN0292005
Spontaneous emission of guided polaritons by quantum dot coupled to metallic nanowire: beyond the dipole approximation
No full textIn this paper, we theoretically analyze the emission of guided
polaritons accompanying spontaneous recombination in a semiconductor
quantum dot coupled to metallic nanowire. This study is aimed to shed
light on the interaction between optically excited quantum emitters and
metallic nanowaveguides beyond the validity of dipole approximation. To
the best of our knowledge, this is the first time the geometry of quantum
emitter and spatial inhomogeneity of the electric field constituting the
fundamental polariton mode are fully taken into account. Even though we
performed the analysis for disk-like quantum dot, all the conclusions are
quite general and remain valid for any emitter with nanometer dimensions.
Particularly, we found that the strong inhomogeneity of the electric field
near the nanowire surface results in a variety of dipole-forbidden transitions
in the quantum dot energy spectra. It was also unambiguously shown that
there is a certain nanowire radius that gives maximum emission efficiency
into the fundamental polariton mode. Since the dipole approximation breaks
for nanowires with small radii and relatively big nanoemitters, the above
features need to be considered in the engineering of plasmonic devices for
nanophotonic networks
Issues in accrual accounting and budgeting by government
No full textThe adoption of accrual accounting and budgeting systems has been central
to the program of Commonwealth Public Sector reforms over the past 20
years. The reforms are explained in publications such as Department of
Finance (DOF, 1994a,b), National Commission of Audit (1996); Guthrie and
Parker (1998); and Wanna, Kelly and Forster (2000). They were heralded with
much praise and promise for improvements in the efficiency of resource
management and effectiveness in policy delivery, and in enhanced transparency of
information and accountability to Parliament and the public. However, while
major improvements have been made in these matters, significant concerns remain
about the new systems and they have created many problems
Metal-free scanning optical microscopy with a fractal fiber probe
No full textScanning Near-field Optical Microscopy (SNOM) is the leading
instrument used to image optical fields on the nanometer scale. A metalcoating
is typically applied to SNOM probes to define a subwavelength
aperture and minimize optical leakage, but the presence of such coatings in
the near field of the sample can often cause a substantial change in the
sample emission properties. For the first time, the authors demonstrate nearfield
imaging on a metal substrate with a metal-free probe made from a
novel structured optical fiber, designed to maximize optical throughput and
potentially remove the need for the metal