2,110 research outputs found
The public's acceptance of novel vaccines during a pandemic: a focus group study and its application to influenza H1N1
As influenza H1N1 spreads around the world, health officials are considering the development and use of a new vaccine to protect the public and help control the outbreak. Acceptance of novel vaccines during health crises, however, is influenced by perceptions of a range of risks, including the risk of infection, risk of becoming severely ill or dying if infected, as well as the risk of serious side and long-term effects of the vaccine. A study on 11 focus groups was conducted with the public in Vancouver, Canada in 2006 and 2007 to explore how people assess these risks and how these assessments relate to their willingness to use novel vaccines in a pandemic. Concerns about using new vaccines during a pandemic differ from concerns about using established products in a non-crisis situation. Participants were hesitant to use novel vaccines because of a low perception of the early risk of infection in a pandemic, coupled with the many uncertainties that surround new vaccines and the emerging infectious disease, and owing to the concern that unsafe pharmaceuticals may be rushed to market during a health crisis. Understanding the public´s assessment of the risks related to, and willingness to use, novel vaccines during a pandemic can help officials promote disease-control measures in ways that improve the likelihood of acceptance by the public and may increase uptake of an H1N1 vaccine
Growth and electronic and magnetic structure of iron oxide films on Pt(111)
Ultrathin (111)-oriented polar iron oxide films were grown on a Pt(111)
single crystal either by the reactive deposition of iron or oxidation of
metallic iron monolayers. These films were characterized using low energy
electron diffraction, scanning tunneling microscopy and conversion electron
Mossbauer spectroscopy. The reactive deposition of Fe led to the island growth
of Fe3O4, in which the electronic and magnetic properties of the bulk material
were modulated by superparamagnetic size effects for thicknesses below 2 nm,
revealing specific surface and interface features. In contrast, the oxide films
with FeO stoichiometry, which could be stabilized as thick as 4 nm under
special preparation conditions, had electronic and magnetic properties that
were very different from their bulk counterpart, w\"ustite. Unusual long range
magnetic order appeared at room temperature for thicknesses between three and
ten monolayers, the appearance of which requires severe structural modification
from the rock-salt structure.Comment: 17 pages, 6 figures, 50 reference
Cleaving-temperature dependence of layered-oxide surfaces
The surfaces generated by cleaving non-polar, two-dimensional oxides are
often considered to be perfect or ideal. However, single particle
spectroscopies on Sr2RuO4, an archetypal non-polar two dimensional oxide, show
significant cleavage temperature dependence. We demonstrate that this is not a
consequence of the intrinsic characteristics of the surface: lattice parameters
and symmetries, step heights, atom positions, or density of states. Instead, we
find a marked increase in the density of defects at the mesoscopic scale with
increased cleave temperature. The potential generality of these defects to
oxide surfaces may have broad consequences to interfacial control and the
interpretation of surface sensitive measurements
The smallest refrigerators can reach maximal efficiency
We investigate whether size imposes a fundamental constraint on the
efficiency of small thermal machines. We analyse in detail a model of a small
self-contained refrigerator consisting of three qubits. We show analytically
that this system can reach the Carnot efficiency, thus demonstrating that there
exists no complementarity between size and efficiency.Comment: 9 pages, 1 figure. v2: published versio
Deploying homeland security technology
The success of each depends on how efficiently they implement new technologies. Although the White House and the Congress have responded swiftly to the events of September 11, 2001, the long-term security of our Nation, and thus the success of the newly created Department of Homeland Security, will depend in a substantial way on the efficiency with which technologies relevant to homeland security are created and, more importantly, deployed. The purpose of this paper is to assess the Administration's revealed understanding of the innovation process, which underlies the creation of new homeland security technology, and attendant factors that relate to the efficiency with which the new technology is deployed. By -revealed understanding‖ we are referring to the written word, namely what is outlined in the Homeland Security Act of 2002 and related documents. Certainly, the Act, and related document s from t he Whit e House, are only init ial templates that frame activities to come. But, as the Brookings Institution's (2002, p. i) early assessment of the Department 's organizat ion, and t he Depart ment 's organization is fundamentally related to its ability to provide incentives for the creation and deployment of homeland security technology, -... while it is possible to revisit or even reverse organizational decisions at a later stage, it is far better to get it right the first time.‖ The Department of Homeland Security will be charged with four primary tasks. The new agency will [1] control our borders and prevent terrorists and explosives from entering our country. It will [2] work with state and local authorities to respond quickly and effectively to emergencies. It will [3] bring together our best scientists to develop technologies that detect biological, chemical, and nuclear weapons, and to discover the drugs and treatments to best protect our citizens. And this new department will [4] review intelligence and law enforcement information from all agencies of government, and produce a single daily picture of threats against our homeland. An emphasis on homeland security technology One of the first policy institutes to offer an opinion on homeland security was the Heritage Foundation (2002). 2 Its report, Defending the American Homeland, recommended four well conceived priorities: protecting the Nation's infrastructures, strengthening civil defense, improving intelligence and law enforcement, and military operations to combat terrorism
Identifying Predictors of Diagnostic Instability of Autism Spectrum Disorder and Global Developmental Delay In Toddlers
Although Autism Spectrum Disorder (ASD) is considered to be a lifelong condition, some toddlers experience diagnostic instability over time. In particular, some toddlers’ diagnosis changes between ASD and Global Developmental Delay (GDD). However, little is known about the subset of children who change diagnosis. In a total of 424 toddlers who either maintained or changed diagnosis, the current study identified predictors of change in diagnosis and severity in those who change from ASD to non-ASD (ASD-NON), ASD to GDD (ASD-GDD), non-ASD to ASD (NON-ASD), and GDD to ASD (GDD-ASD) between two years old and four years old. Initial ASD symptom severity and participation in intervention services were predictive of all transitions. Additionally, receptive language predicted ASD-NON transition and socioeconomic status predicted ASD-GDD transition. Implications for informing prognosis of children, identifying targets of intervention, refining of screening and diagnostic measures, and measuring change in severity regardless of categorical change are discussed
Structure, stability, and mobility of small Pd clusters on the stoichiometric and defective TiO (110) surfaces
We report on the structure and adsorption properties of Pd ()
clusters supported on the rutile TiO (110) surfaces with the possible
presence of a surface oxygen vacancy or a subsurface Ti-interstitial atom. As
predicted by the density functional theory, small Pd clusters prefer to bind to
the stoichiometric titania surface or at sites near subsurface Ti-interstitial
atoms. The adsorption of Pd clusters changes the electronic structure of the
underlying surface. For the surface with an oxygen vacancy, the charge
localization and ferromagnetic spin states are found to be largely attenuated
owing to the adsorption of Pd clusters. The potential energy surfaces of the Pd
monomer on different types of surfaces are also reported. The process of
sintering is then simulated via the Metropolis Monte Carlo method. The presence
of oxygen vacancy likely leads to the dissociation of Pd clusters. On the
stoichiometric surface or surface with Ti-interstitial atom, the Pd monomers
tend to sinter into larger clusters, whereas the Pd dimer, trimer and tetramer
appear to be relatively stable below 600 K. This result agrees with the
standard sintering model of transition metal clusters and experimental
observations.Comment: 27 pages, 11 figure
Rapid cultural adaptation can facilitate the evolution of large-scale cooperation
Over the past several decades, we have argued that cultural evolution can facilitate the evolution of large-scale cooperation because it often leads to more rapid adaptation than genetic evolution, and, when multiple stable equilibria exist, rapid adaptation leads to variation among groups. Recently, Lehmann, Feldman, and colleagues have published several papers questioning this argument. They analyze models showing that cultural evolution can actually reduce the range of conditions under which cooperation can evolve and interpret these models as indicating that we were wrong to conclude that culture facilitated the evolution of human cooperation. In the main, their models assume that rates of cultural adaption are not strong enough compared to migration to maintain persistent variation among groups when payoffs create multiple stable equilibria. We show that Lehmann et al. reach different conclusions because they have made different assumptions. We argue that the assumptions that underlie our models are more consistent with the empirical data on large-scale cultural variation in humans than those of Lehmann et al., and thus, our models provide a more plausible account of the cultural evolution of human cooperation in large groups
A combinatorial approach to knot recognition
This is a report on our ongoing research on a combinatorial approach to knot
recognition, using coloring of knots by certain algebraic objects called
quandles. The aim of the paper is to summarize the mathematical theory of knot
coloring in a compact, accessible manner, and to show how to use it for
computational purposes. In particular, we address how to determine colorability
of a knot, and propose to use SAT solving to search for colorings. The
computational complexity of the problem, both in theory and in our
implementation, is discussed. In the last part, we explain how coloring can be
utilized in knot recognition
Mobile Communication Signatures of Unemployment
The mapping of populations socio-economic well-being is highly constrained by
the logistics of censuses and surveys. Consequently, spatially detailed changes
across scales of days, weeks, or months, or even year to year, are difficult to
assess; thus the speed of which policies can be designed and evaluated is
limited. However, recent studies have shown the value of mobile phone data as
an enabling methodology for demographic modeling and measurement. In this work,
we investigate whether indicators extracted from mobile phone usage can reveal
information about the socio-economical status of microregions such as districts
(i.e., average spatial resolution < 2.7km). For this we examine anonymized
mobile phone metadata combined with beneficiaries records from unemployment
benefit program. We find that aggregated activity, social, and mobility
patterns strongly correlate with unemployment. Furthermore, we construct a
simple model to produce accurate reconstruction of district level unemployment
from their mobile communication patterns alone. Our results suggest that
reliable and cost-effective economical indicators could be built based on
passively collected and anonymized mobile phone data. With similar data being
collected every day by telecommunication services across the world,
survey-based methods of measuring community socioeconomic status could
potentially be augmented or replaced by such passive sensing methods in the
future
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