2,710 research outputs found
Designing and conducting tabletop exercises to assess public health preparedness for manmade and naturally occurring biological threats
<p>Abstract</p> <p>Background</p> <p>Since 2001, state and local health departments in the United States (US) have accelerated efforts to prepare for high-impact public health emergencies. One component of these activities has been the development and conduct of exercise programs to assess capabilities, train staff and build relationships. This paper summarizes lessons learned from tabletop exercises about public health emergency preparedness and about the process of developing, conducting, and evaluating them.</p> <p>Methods</p> <p>We developed, conducted, and evaluated 31 tabletop exercises in partnership with state and local health departments throughout the US from 2003 to 2006. Participant self evaluations, after action reports, and tabletop exercise evaluation forms were used to identify aspects of the exercises themselves, as well as public health emergency responses that participants found more or less challenging, and to highlight lessons learned about tabletop exercise design.</p> <p>Results</p> <p>Designing the exercises involved substantial collaboration with representatives from participating health departments to assure that the scenarios were credible, focused attention on local preparedness needs and priorities, and were logistically feasible to implement. During execution of the exercises, nearly all health departments struggled with a common set of challenges relating to disease surveillance, epidemiologic investigations, communications, command and control, and health care surge capacity. In contrast, performance strengths were more varied across participating sites, reflecting specific attributes of individual health departments or communities, experience with actual public health emergencies, or the emphasis of prior preparedness efforts.</p> <p>Conclusion</p> <p>The design, conduct, and evaluation of the tabletop exercises described in this report benefited from collaborative planning that involved stakeholders from participating health departments and exercise developers and facilitators from outside the participating agencies. While these exercises identified both strengths and vulnerabilities in emergency preparedness, additional work is needed to develop reliable metrics to gauge exercise performance, inform follow-up action steps, and to develop re-evaluation exercise designs that assess the impact of post-exercise interventions.</p
Red Quasars and Quasar Evolution: the Case of BALQSO FIRST J155633.8+351758
We present the first near-IR spectroscopy of the z=1.5 radio-loud BALQSO
FIRST J155633.8+351758. Both the Balmer decrement and the slope of the
rest-frame UV-optical continuum independently suggest a modest amount of
extinction along the line of sight to the BLR (E(B-V)~0.5 for SMC-type screen
extinction at the QSO redshift). The implied gas column density along the line
of sight is much less than is implied by the weak X-ray flux of the object,
suggesting that either the BLR and BAL region have a low dust-to-gas ratio, or
that the rest-frame optical light encounters significantly lower mean column
density lines of sight than the X-ray emission. From the rest-frame UV-optical
spectrum, we are able to constrain the stellar mass content of the system.
Comparing the maximal stellar mass with the black hole mass estimated from the
bolometric luminosity of the QSO, we find that the ratio of the black hole to
stellar mass may be comparable to the Magorrian value, which would imply that
the Magorrian relation is already in place at z=1.5. However, multiple factors
favor a much larger black hole to stellar mass ratio. This would imply that if
the Magorrian relation characterizes the late history of QSOs, and the
situation observed for F1556+3517 is typical of the early evolutionary history
of QSOs, central black hole masses develop more rapidly than bulge masses.
[ABRIDGED]Comment: 23 pages, 4 embedded postscript figures; Accepted for publication in
The Astronomical Journal, December 200
Behavioral responses of voles along fences patrolled by natural predators
Fuelling, O., Buehler, E., Airoldi, J.-P., Nentwig, W
Bench-scale synthesis of nanoscale materials
A novel flow-through hydrothermal method used to synthesize nanoscale powders is introduced by Pacific Northwest Laboratory. The process, Rapid Thermal Decomposition of precursors in Solution (RTDS), uniquely combines high-pressure and high-temperature conditions to rapidly form nanoscale particles. The RTDS process was initially demonstrated on a laboratory scale and was subsequently scaled up to accommodate production rates attractive to industry. The process is able to produce a wide variety of metal oxides and oxyhydroxides. The powders are characterized by scanning and transmission electron microscopic methods, surface-area measurements, and x-ray diffraction. Typical crystallite sizes are less than 20 nanometers, with BET surface areas ranging from 100 to 400 sq m/g. A description of the RTDS process is presented along with powder characterization results. In addition, data on the sintering of nanoscale ZrO2 produced by RTDS are included
Density dependent spin polarisation in ultra low-disorder quantum wires
There is controversy as to whether a one-dimensional (1D) electron gas can
spin polarise in the absence of a magnetic field. Together with a simple model,
we present conductance measurements on ultra low-disorder quantum wires
supportive of a spin polarisation at B=0. A spin energy gap is indicated by the
presence of a feature in the range 0.5 - 0.7 X 2e^2/h in conductance data.
Importantly, it appears that the spin gap is not static but a function of the
electron density. Data obtained using a bias spectroscopy technique are
consistent with the spin gap widening further as the Fermi-level is increased.Comment: 5 Pages 4 Figures email:[email protected]
Parity measurement of one- and two-electron double well systems
We outline a scheme to accomplish measurements of a solid state double well
system (DWS) with both one and two electrons in non-localised bases. We show
that, for a single particle, measuring the local charge distribution at the
midpoint of a DWS using an SET as a sensitive electrometer amounts to
performing a projective measurement in the parity (symmetric/antisymmetric)
eigenbasis. For two-electrons in a DWS, a similar configuration of SET results
in close-to-projective measurement in the singlet/triplet basis. We analyse the
sensitivity of the scheme to asymmetry in the SET position for some
experimentally relevant parameter, and show that it is realisable in
experiment.Comment: 18 Pages, to appear in PR
Self-aligned fabrication process for silicon quantum computer devices
We describe a fabrication process for devices with few quantum bits (qubits),
which are suitable for proof-of-principle demonstrations of silicon-based
quantum computation. The devices follow the Kane proposal to use the nuclear
spins of 31P donors in 28Si as qubits, controlled by metal surface gates and
measured using single electron transistors (SETs). The accurate registration of
31P donors to control gates and read-out SETs is achieved through the use of a
self-aligned process which incorporates electron beam patterning, ion
implantation and triple-angle shadow-mask metal evaporation
Current issues in research on structure–property relationships in polymer nanocomposites
The understanding of the basic physical relationships between nano-scale structural variables and the macroscale properties of polymer nanocomposites remains in its infancy. The primary objective of this article is to ascertain the state of the art regarding the understanding and prediction of the macroscale properties of polymers reinforced with nanometer-sized solid inclusions over a wide temperature range. We emphasize that the addition of nanoparticles with large specific surface area to polymer matrices leads to amplification of a number of rather distinct molecular processes resulting from interactions between chains and solid surfaces. This results in a “non-classical” response of these systems to mechanical and electro-optical excitations when measured on the macroscale. For example, nanoparticles are expected to be particularly effective at modifying the intrinsic nano-scale dynamic heterogeneity of polymeric glass-formation and, correspondingly, recent simulations indicate that both the strength of particle interaction with the polymer matrix and the particle concentration can substantially influence the dynamic fragility of polymer glass-formation, a measure of the strength of the temperature dependence of the viscosity or structural relaxation time. Another basic characteristic of nanoparticles in polymer matrices is the tendency for the particles to associate into extended structures that can dominate the rheological, viscoelastic and mechanical properties of the nanocomposite so that thermodynamic factors that effect nanoparticle dispersion can be crucially important. Opportunities to exploit knowledge gained from understanding biomechanics of hierarchical biological protein materials and potential applications in materials design and nanotechnology are among future research challenges. Research on nanocomposites formed from block copolymers and nanoparticles offers huge promise in molecular electronics and photovoltaics. The surface functionalization of nanoparticles by the grafting of polymer brushes is expected to play important role in the designing of novel organic/inorganic nanocomposite materials. The formation of bulk heterojunctions at the nanometer scale leads to efficient dissociation of the charge pairs generated under sunlight. Based on the presentations and discussion, we make recommendations for future work in this area by the physics, chemistry, and engineering communities.Czech Republic. Ministry of Education, Youth, and Sports (MSM0021630501
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