Metamaterial Polarization Converter Analysis: Limits of Performance

In this paper we analyze the theoretical limits of a metamaterial converter that allows for linear-to- elliptical polarization transformation with any desired ellipticity and ellipse orientation. We employ the transmission line approach providing a needed level of the design generalization. Our analysis reveals that the maximal conversion efficiency for transmission through a single metamaterial layer is 50%, while the realistic re ection configuration can give the conversion efficiency up to 90%. We show that a double layer transmission converter and a single layer with a ground plane can have 100% polarization conversion efficiency. We tested our conclusions numerically reaching the designated limits of efficiency using a simple metamaterial design. Our general analysis provides useful guidelines for the metamaterial polarization converter design for virtually any frequency range of the electromagnetic waves.Comment: 10 pages, 11 figures, 2 table

Equations of State in the Brans-Dicke cosmology

We investigate the Brans-Dicke (BD) theory with the potential as cosmological model to explain the present accelerating universe. In this work, we consider the BD field as a perfect fluid with the energy density and pressure in the Jordan frame. Introducing the power-law potential and the interaction with the cold dark matter, we obtain the phantom divide which is confirmed by the native and effective equation of state. Also we can describe the metric $f(R)$ gravity with an appropriate potential, which shows a future crossing of phantom divide in viable $f(R)$ gravity models when employing the native and effective equations of state.Comment: 23 pages, 7 figure

Hydroclimate footprint of pan-Asian monsoon water isotope during the last deglaciation

Oxygen isotope speleothem records exhibit coherent variability over the pan-Asian summer monsoon (AM) region. The hydroclimatic representation of these oxygen isotope records for the AM, however, has remained poorly understood. Here, combining an isotope-enabled Earth system model in transient experiments with proxy records, we show that the widespread AM delta O-18(c) signal during the last deglaciation (20 to 11 thousand years ago) is accompanied by a continental-scale, coherent hydroclimate footprint, with spatially opposite signs in rainfall. This footprint is generated as a dynamically coherent response of the AM system primarily to meltwater forcing and secondarily to insolation forcing and is further reinforced by atmospheric teleconnection. Hence, widespread delta O-18(p) depletion in the AM region is accompanied by a northward migration of the westerly jet and enhanced southwesterly monsoon wind, as well as increased rainfall from South Asia (India) to northern China but decreased rainfall in southeast China

Impact of a Tutored Theoretical-Practical Training to Develop Undergraduate Students’ Skills for the Detection of Caries Lesions: Study Protocol for a Multicenter Controlled Randomized Study

Background: Tutored laboratorial activities could be a manner of improving the competency development of students. However, its impact over conventional theoretical classes has not yet been tested. Additionally, different university contexts could influence this issue and should be explored. Objective: To assess the impact of a tutored theoretical-practical training for teaching undergraduate students to detect caries lesions as compared with theoretical teaching activities. The impact of these teaching/learning activities will be assessed in terms of efficacy, cost/benefit, retention of knowledge/acquired competences, and student acceptability. Methods: Sixteen centers (7 centers from Brazil and 9 centers from other countries throughout the world) are involved in the inclusion of subjects for this protocol. A randomized controlled study with parallel groups will be conducted. One group (control) will be exposed to a 60- to 90-minute conventional theoretical class and the other group (test) will be exposed to the same theoretical class and also a 90-minute laboratory class, including exercises and discussions based on the evaluation of a pool of images and extracted teeth. The mentioned outcomes will be evaluated immediately after the teaching activities and also in medium- and long-term analyses. To compare the long-term outcomes, students who enrolled in the university before the participating students will be interviewed for data collection and these data will be used as a control and compared with the trained group. This stage will be a nonrandomized phase of this study, nested in the main study. Appropriate statistical analysis will be performed according to the aims of this study. Variables related to the centers will also be analyzed and used to model adjustment as possible sources of variability among results. Results: This ongoing study is funded by a Brazilian national funding agency (CNPq- 400736/2014-4). We expect that the tutored theoretical-practical training will improve the undergraduate students’ performance in the detection of caries lesions and subsequent treatment decisions, mainly in terms of long-term retention of knowledge. Our hypothesis is that tutored theoretical-practical training is a more cost-effective option for teaching undergraduate students to detect caries lesions. Conclusions: If our hypothesis is confirmed, the use of laboratory training in conjunction with theoretical classes could be used as an educational strategy in Cariology to improve the development of undergraduate students’ skills in the detection of caries lesions and clinical decision-making

Functional mechanisms underlying pleiotropic risk alleles at the 19p13.1 breast-ovarian cancer susceptibility locus

A locus at 19p13 is associated with breast cancer (BC) and ovarian cancer (OC) risk. Here we analyse 438 SNPs in this region in 46,451 BC and 15,438 OC cases, 15,252 BRCA1 mutation carriers and 73,444 controls and identify 13 candidate causal SNPs associated with serous OC (P=9.2 × 10-20), ER-negative BC (P=1.1 × 10-13), BRCA1-associated BC (P=7.7 × 10-16) and triple negative BC (P-diff=2 × 10-5). Genotype-gene expression associations are identified for candidate target genes ANKLE1 (P=2 × 10-3) and ABHD8 (P<2 × 10-3). Chromosome conformation capture identifies interactions between four candidate SNPs and ABHD8, and luciferase assays indicate six risk alleles increased transactivation of the ADHD8 promoter. Targeted deletion of a region containing risk SNP rs56069439 in a putative enhancer induces ANKLE1 downregulation; and mRNA stability assays indicate functional effects for an ANKLE1 3′-UTR SNP. Altogether, these data suggest that multiple SNPs at 19p13 regulate ABHD8 and perhaps ANKLE1 expression, and indicate common mechanisms underlying breast and ovarian cancer risk

Track A Basic Science

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138319/1/jia218438.pd

Thermocatalytic routes and reactor strategies for valorization of biodiesel-derived glycerol to fuels

Glycerol is an oversupplied commodity from biodiesel production with beneficial properties for the synthesis of versatile utility biochemicals. The functional properties of glycerol with three hydroxyl groups could be tailored toward producing fuels such as hydrogen, syngas, C1-C3 hydrocarbon fuel, bio-oil and methane. This study elucidates the reported thermochemical pathways such as pyrolysis, gasification, combustion, steam and aqueous reforming, and supercritical water gasification for fuel production from biodiesel-derived glycerol. The mechanism of these pathways, process conditions, catalytic integration, and limitations were investigated. Also, reactor strategies such as fixed bed reactors, fluidized bed, and solar reactor strategies used for the thermochemical valorization of glycerol was discussed. The studies revealed that hydrogen up to 70% yield could be generated from glycerol using noble metals and nickel-based catalysts. Catalyst deactivation due to coking could be minimized by the addition of alkaline metals, which discourages methanation reaction. Reaction parameters such as temperature, catalyst amount, time on stream, and glycerol/water or steam ratio influence the product distribution. The glycerol steam reforming is more energy-intensive and requires temperatures in the range of 450–1000 °C, whereas the aqueous reforming is propagated in the range of 180–250 °C. The circulating fluidized bed reactors limit coking due to self-regeneration of the catalysts in situ, however, they are cost-intensive. Life cycle assessment analysis revealed that supercritical water reforming (SCWR) of glycerol offers a sustainable pathway to reduce CO2 by 95% and integration of SCWR in biodiesel plants to produce hydrogen for heating can realize a net present value between 7.70 and 15.70 million USD. Further studies to analyze the economic impact of the individual pathways to optimize the production of fuels from glycerol are required. It is hoped that this study will engage industries and researchers to increasingly use glycerol as a substrate for the production of fuels for transportation.Dirección General de Asuntos del Personal Académico, Universidad Nacional Autónoma de México - grant no. IA102522, IA102821, IA203320, IG100720

LearnPNP: A Tool for Learning Agent Behaviors

High-level programming of robotic agents requires the use of a representation formalism able to cope with several sources of complexity (e.g. parallel execution, partial observability, exogenous events, etc.) and the ability of the designer to model the domain in a precise way. Reinforcement Learning has proved promising in improving the performance, adaptability and robustness of plans in under-specified domains, although it does not scale well with the complexity of common robotic applications. In this paper we propose to combine an extremely expressive plan representation formalism (Petri Net Plans), with Reinforcement Learning over a stochastic process derived directly from such a plan. The derived process has a significantly reduced search space and thus the framework scales well with the complexity of the domain and allows for actually improving the performance of complex behaviors from experience. To prove the effectiveness of the system, we show how to model and learn the behavior of the robotic agents in the context of Keepaway Soccer (a widely accepted benchmark for RL) and the RoboCup Standard Platform League. © 2011 Springer-Verlag