85 research outputs found
A Hybrid Achromatic Metalens
Metamaterials and metasurfaces are widely used to manipulate electromagnetic
waves over a broad range of wavelengths. Several recent efforts have focused on
metalenses, ultra-thin optical elements that focus light using subwavelength
structures. Compared to their refractive counterparts, metalenses offer reduced
size and weight, improved manufacturability, and new functionality such as
polarization control. However, metalenses that correct chromatic aberration
also suffer from markedly reduced focusing efficiency. Here we introduce a
Hybrid Achromatic Metalens (HAML), that overcomes this trade-off and offers
improved focusing efficiency over a broad wavelength range from 1000 - 1800 nm.
Fabricated HAMLs demonstrated diffraction limited performance for numerical
apertures (NA) of 0.27, 0.11, and 0.06 with average focusing efficiencies and maximum efficiencies ~ . HAMLs can be designed by combining
recursive ray-tracing and simulated phase libraries rather than computational
intensive global search algorithms. Moreover, HAMLs can be fabricated in
low-refractive index materials using multi-photon lithography for customization
or using molding for mass production.Comment: 20 pages, 7 figure
Experimental and theoretical investigation of waveguided plasmonic surface lattice resonances
Plasmonic nanostructures are good candidates for refractive index sensing applications through the surface plasmon resonance due to their strong dependence on the surrounding dielectric media. However, typically low quality-factor limits their application in sensing devices. To improve the quality-factor, we have experimentally and theoretically investigated two-dimensional gold nanoparticle gratings situated on top of a waveguide. The coupling between the localized surface plasmon and waveguide modes results in Fano-type resonances, with high quality-factors, very similar to plasmonic surface lattice resonances. By combining plasmonic surface lattice resonance and waveguide theory, we present a theoretical framework describing the structures. By immersing the fabricated samples in three different media we find a sensitivity of ∼50 nm/RIU and figure of merit of 8.9, and demonstrate good agreement with the theory presented. Further analysis show that the sensitivity is very dependent on the waveguide parameters, grating constant and the dielectric environment, and by tuning these parameters we obtain a theoretical sensitivity of 887 nm/RIU.publishedVersio
TCT-266 A Randomized Comparison of Transradial versus Transfemoral Approach for Coronary Artery Bypass Graft Angiography and Intervention (the RADIAL CABG trial)
Electromagnetic channel capacity for practical purposes
We give analytic upper bounds to the channel capacity C for transmission of
classical information in electromagnetic channels (bosonic channels with
thermal noise). In the practically relevant regimes of high noise and low
transmissivity, by comparison with know lower bounds on C, our inequalities
determine the value of the capacity up to corrections which are irrelevant for
all practical purposes. Examples of such channels are radio communication,
infrared or visible-wavelength free space channels. We also provide bounds to
active channels that include amplification.Comment: 6 pages, 3 figures. NB: the capacity bounds are constructed by
generalizing to the multi-mode case the minimum-output entropy bounds of
arXiv:quant-ph/0404005 [Phys. Rev. A 70, 032315 (2004)
TCT-523 Multicenter Registry for Peripheral Arterial Disease Interventions and Outcomes (XLPAD Registry)
Cosmological parameters from SDSS and WMAP
We measure cosmological parameters using the three-dimensional power spectrum
P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in
combination with WMAP and other data. Our results are consistent with a
``vanilla'' flat adiabatic Lambda-CDM model without tilt (n=1), running tilt,
tensor modes or massive neutrinos. Adding SDSS information more than halves the
WMAP-only error bars on some parameters, tightening 1 sigma constraints on the
Hubble parameter from h~0.74+0.18-0.07 to h~0.70+0.04-0.03, on the matter
density from Omega_m~0.25+/-0.10 to Omega_m~0.30+/-0.04 (1 sigma) and on
neutrino masses from <11 eV to <0.6 eV (95%). SDSS helps even more when
dropping prior assumptions about curvature, neutrinos, tensor modes and the
equation of state. Our results are in substantial agreement with the joint
analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive
consistency check with independent redshift survey data and analysis
techniques. In this paper, we place particular emphasis on clarifying the
physical origin of the constraints, i.e., what we do and do not know when using
different data sets and prior assumptions. For instance, dropping the
assumption that space is perfectly flat, the WMAP-only constraint on the
measured age of the Universe tightens from t0~16.3+2.3-1.8 Gyr to
t0~14.1+1.0-0.9 Gyr by adding SDSS and SN Ia data. Including tensors, running
tilt, neutrino mass and equation of state in the list of free parameters, many
constraints are still quite weak, but future cosmological measurements from
SDSS and other sources should allow these to be substantially tightened.Comment: Minor revisions to match accepted PRD version. SDSS data and ppt
figures available at http://www.hep.upenn.edu/~max/sdsspars.htm
Cross-Serotype Immunity Induced by Immunization with a Conserved Rhinovirus Capsid Protein
Human rhinovirus (RV) infections are the principle cause of common colds and precipitate asthma and COPD exacerbations. There is currently no RV vaccine, largely due to the existence of ∼150 strains. We aimed to define highly conserved areas of the RV proteome and test their usefulness as candidate antigens for a broadly cross-reactive vaccine, using a mouse infection model. Regions of the VP0 (VP4+VP2) capsid protein were identified as having high homology across RVs. Immunization with a recombinant VP0 combined with a Th1 promoting adjuvant induced systemic, antigen specific, cross-serotype, cellular and humoral immune responses. Similar cross-reactive responses were observed in the lungs of immunized mice after infection with heterologous RV strains. Immunization enhanced the generation of heterosubtypic neutralizing antibodies and lung memory T cells, and caused more rapid virus clearance. Conserved domains of the RV capsid therefore induce cross-reactive immune responses and represent candidates for a subunit RV vaccine
Depressive Symptoms in Children with Chronic Kidney Disease
To assess depression in children with chronic kidney disease (CKD) and to determine associations with patient characteristics, intellectual and educational levels, and health related quality of life (HRQoL)
Creating symbolic cultures of consumption: an analysis of the content of sports wagering advertisements in Australia
Background: Since 2008, Australia has seen the rapid emergence of marketing for online and mobile sports wagering. Previous research from other areas of public health, such as tobacco and alcohol, has identified the range of appeal strategies these industries used to align their products with culturally valued symbols. However, there is very limited research that has investigated the tactics the sports wagering industry uses within marketing to influence the consumption of its products and services. Method: This study consisted of a mixed method interpretive content analysis of 85 sports wagering advertisements from 11 Australian and multinational wagering companies. Advertisements were identified via internet searches and industry websites. A coding framework was applied to investigate the extent and nature of symbolic appeal strategies within advertisements. Results: Ten major appeal strategies emerged from this analysis. These included sports fan rituals and behaviours; mateship; gender stereotypes; winning; social status; adventure, thrill and risk; happiness; sexualised imagery; power and control; and patriotism. Symbols relating to sports fan rituals and behaviours, and mateship, were the most common strategies used within the advertisements. Discussion/Conclusions: This research suggests that the appeal strategies used by the sports wagering industry are similar to those strategies adopted by other unhealthy commodity industries. With respect to gambling, analysis revealed that strategies are clearly targeted to young male sports fans. Researchers and public health practitioners should seek to better understand the impact of marketing on the normalisation of sports wagering for this audience segment, and implement strategies to prevent gambling harm
Less is Different: Emergence and Reduction Reconciled
This is a companion to another paper. Together they rebut two widespread
philosophical doctrines about emergence. The first, and main, doctrine is that
emergence is incompatible with reduction. The second is that emergence is
supervenience; or more exactly, supervenience without reduction. In the other
paper, I develop these rebuttals in general terms, emphasising the second
rebuttal. Here I discuss the situation in physics, emphasising the first
rebuttal. I focus on limiting relations between theories and illustrate my
claims with four examples, each of them a model or a framework for modelling,
from well-established mathematics or physics. I take emergence as behaviour
that is novel and robust relative to some comparison class. I take reduction
as, essentially, deduction. The main idea of my first rebuttal will be to
perform the deduction after taking a limit of some parameter. Thus my first
main claim will be that in my four examples (and many others), we can deduce a
novel and robust behaviour, by taking the limit, N goes to infinity, of a
parameter N. But on the other hand, this does not show that that the infinite
limit is "physically real", as some authors have alleged. For my second main
claim is that in these same examples, there is a weaker, yet still vivid, novel
and robust behaviour that occurs before we get to the limit, i.e. for finite N.
And it is this weaker behaviour which is physically real. My examples are: the
method of arbitrary functions (in probability theory); fractals (in geometry);
superselection for infinite systems (in quantum theory); and phase transitions
for infinite systems (in statistical mechanics).Comment: 75 p
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