7,355 research outputs found
Are Consumers Indeed Misled? Congruency in Consumers' Attitudes towards Wine Labeling Information versus Revealed Preferences from a Choice Experiment
Please Contact Authors for Updated Version before Citingdiscrete choice experiment vs. attitude measurement, food labeling, willingness to pay, consumers, wine, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing,
Using Best-Worst Scaling to Determine Market Channel Choice by Small Farmers in Indonesia
A household survey and a novel Best-Worst scaling method are used to examine the relative importance of various buyer characteristics to small potato farmers in Indonesia. A Latent Class Cluster Analysis is used explore whether producers’ utilities for marketing channels are heterogeneous. For the aggregate sample, the attributes related to the buyer providing immediate cash payment, a price premium and always following through on their commitment to buy their potatoes were the three most important attributes. The results of the Latent Class Cluster Analysis found four unique classes or segments of producers, each with distinct utilities for buyer characteristics and interesting differences socio-demographic characteristics. The largest segment (44%) was relatively similar to the aggregate, placing a high importance on cash payment, price and willingness to negotiate. Two segments, 24% and 16% of producers placed a relatively high importance on the buyer providing access to certified potato seed or finance for purchasing inputs, and another segment placed the highest importance on having a long-term relationship with their buyer. This has interesting implications for traders, particularly traders who are interested in securing a long-term relationship with potato producers – simply being able to provide cash at the time potatoes are delivered and/or a small premium may immediately increase the strength of the relationship.Best-Worst Scaling, Latent Class Cluster Analysis, marketing channel choice, Indonesia, potato farmers, small farmers, Marketing,
Analysis of consumer preferences for information and expert opinion using a discrete choice experiment
We present a study of consumer preferences for information in wine purchases. Consumers are presented with extra information in the form of qualitative product descriptions and quantitative expert ratings. We implement a discrete choice exper- iment in which we vary experimentally the presence of the descriptions and ratings and the values of the ratings themselves. Respondents are asked to choose amongst a set of 5 wine bottles in a sequence of 21 choice scenarios. We find that the presence of extra information and high expert ratings have a significant impact on the will- ingness to pay for a given wine. The dispersion of ratings for a given wine does not affect respondents’ choices. In our estimates high average ratings by experts carry a premium of AUD $10.info:eu-repo/semantics/publishedVersio
Device physics of van der Waals heterojunction solar cells
Heterostructures based on atomically thin semiconductors are considered a
promising emerging technology for the realization of ultrathin and ultralight
photovoltaic solar cells on flexible substrates. Much progress has been made in
recent years on a technological level, but a clear picture of the physical
processes that govern the photovoltaic response remains elusive. Here, we
present a device model that is able to fully reproduce the current-voltage
characteristics of type-II van der Waals heterojunctions under optical
illumination, including some peculiar behaviors such as exceedingly high
ideality factors or bias-dependent photocurrents. While we find the spatial
charge transfer across the junction to be very efficient, we also find a
considerable accumulation of photogenerated carriers in the active device
region due to poor electrical transport properties, giving rise to significant
carrier recombination losses. Our results are important to optimize future
device architectures and increase power conversion efficiencies of atomically
thin solar cells.Comment: 20 pages, 5 figure
Controlled generation of a pn-junction in a waveguide integrated graphene photodetector
With its electrically tunable light absorption and ultrafast photoresponse,
graphene is a promising candidate for high-speed chip-integrated photonics. The
generation mechanisms of photosignals in graphene photodetectors have been
studied extensively in the past years. However, the knowledge about efficient
light conversion at graphene pn-junctions has not yet been translated into
high-performance devices. Here, we present a graphene photodetector integrated
on a silicon slot-waveguide, acting as a dual-gate to create a pn-junction in
the optical absorption region of the device. While at zero bias the
photo-thermoelectric effect is the dominant conversion process, an additional
photoconductive contribution is identified in a biased configuration. Extrinsic
responsivities of 35 mA/W, or 3.5 V/W, at zero bias and 76 mA/W at 300 mV bias
voltage are achieved. The device exhibits a 3 dB-bandwidth of 65 GHz, which is
the highest value reported for a graphene-based photodetector.Comment: 19 pages, 16 figure
Fast shower simulation in the ATLAS calorimeter
The time to simulate pp collisions in the ATLAS detector is largely dominated by the showering of electromagnetic particles in the heavy parts of the detector, especially the electromagnetic barrel and endcap calorimeters. Two procedures have been developed to accelerate the processing time of electromagnetic particles in these regions: (1) a fast shower parameterisation and (2) a frozen shower library. Both work by generating the response of the calorimeter to electrons and positrons with Geant 4, and then reintroduce the response into the simulation at runtime.
In the fast shower parameterisation technique, a parameterisation is tuned to single electrons and used later by simulation. In the frozen shower technique, actual showers from low-energy particles are used in the simulation. Full Geant 4 simulation is used to develop showers down to ~1 GeV, at which point the shower is terminated by substituting a frozen shower. Judicious use of both techniques over the entire electromagnetic portion of the ATLAS calorimeter produces an important improvement of CPU time. We discuss the algorithms and their performance in this paper
Color-stable, ITO-free white organic light-emitting diodes with enhanced efficiency using solution-processed transparent electrodes and optical outcoupling layers
In this work, we demonstrate color-stable, ITO-free white organic light-emitting diodes (WOLEDs) with enhanced efficiencies by combining the high-conductivity conducting polymer PEDOT:PSS as transparent electrode and a nanoparticle-based scattering layer (NPSL) as the effective optical out-coupling layer. In addition to efficiency enhancement, the NPSL is also beneficial to the stabilization of electroluminescent spectra/colors over viewing angles. Both the PEDOT:PSS and the NPSL can be fabricated by simple, low-temperature solution processing. The integration of both solution-processable transparent electrodes and light extraction structures into OLEDs is particularly attractive for applications since they simultaneously provide manufacturing, cost and efficiency advantages. PostprintPeer reviewe
Space-time reduced basis methods for parametrized unsteady Stokes equations
In this work, we analyse space-time reduced basis methods for the efficient
numerical simulation of hemodynamics in arteries. The classical formulation of
the reduced basis (RB) method features dimensionality reduction in space, while
finite differences schemes are employed for the time integration of the
resulting ordinary differential equation (ODE). Space-time reduced basis
(ST-RB) methods extend the dimensionality reduction paradigm to the temporal
dimension, projecting the full-order problem onto a low-dimensional
spatio-temporal subspace. Our goal is to investigate the application of ST-RB
methods to the unsteady incompressible Stokes equations, with a particular
focus on stability. High-fidelity simulations are performed using the Finite
Element (FE) method and BDF2 as time marching scheme. We consider two different
ST-RB methods. In the first one - called ST-GRB - space-time model order
reduction is achieved by means of a Galerkin projection; a spatio-temporal
velocity basis enrichment procedure is introduced to guarantee stability. The
second method - called ST-PGRB - is characterized by a Petrov--Galerkin
projection, stemming from a suitable minimization of the FOM residual, that
allows to automatically attain stability. The classical RB method - denoted as
SRB-TFO - serves as a baseline for the theoretical development. Numerical tests
have been conducted on an idealized symmetric bifurcation geometry and on the
patient-specific one of a femoropopliteal bypass. The results show that both
ST-RB methods provide accurate approximations of the high-fidelity solutions,
while considerably reducing the computational cost. In particular, the ST-PGRB
method exhibits the best performance, as it features a better computational
efficiency while retaining accuracies in accordance with theoretical
expectations.Comment: 30 pages (25 + 5 in appendix), 4 figures, 4 tables. To appear on SIAM
Journal on Scientific Computing (SISC
Durabilité de la culture cotonnière selon l'utilisation des insecticides : cas du Togo de 1991-2010
Dans la perception des profanes, le coton est encore associé à la culture consommant le plus d'insecticides néfastes pour la santé et l'environnement. Une telle mauvaise image n'est plus méritée selon une étude internationale, mais les pays producteurs ont peu analysé et informé sur l'évolution de l'utilisation d'insecticides. Cette communication comble la lacune dans le cas du Togo. L'étude est basée sur la reconstitution des séries de données des surfaces emblavées et d'insecticides distribués aux producteurs de coton du Togo, de 1990 à 2010. Les données sur les insecticides concernent les volumes distribués ainsi que leurs compositions en matières actives, permettant ainsi de déduire la consommation de matières actives par hectare. Par ailleurs, les charges toxicologiques vis-à-vis de divers éléments de la faune ont été calculées à partir des indices d'écotoxicité établis par la FAO pour chaque matière active. La consommation de matières actives insecticides au Togo a chuté régulièrement jusqu'à un litre/hectare, du même niveau que l'Australie qui recourt par ailleurs aux variétés génétiquement modifiées. La charge toxicologique, pesant sur l'homme mais aussi sur divers éléments de la faune comme les abeilles ou les daphnés des cours d'eau, a diminué quoique de manière moins régulière. Cette évolution est la conséquence d'une protection limitée depuis trois décennies à moins de six traitements et de l'adoption de nouvelles générations de molécules insecticides. Au Togo, l'utilisation des insecticides dans la culture cotonnière a évolué dans une direction plus compatible avec le souci de la santé humaine et de la préservation de l'environnement, mais cette évolution est extrapolable à tous les pays cotonniers de l'Afrique francophone. Il convient de poursuivre l'évolution engagée dans les décisions relatives aux insecticides à commander, en s'inspirant des indicateurs utilisés dans cette étude. (Résumé d'auteur
TGA2 signaling in response to reactive electrophile species is not dependent on cysteine modification of TGA2
This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Reactive electrophile species (RES), including prostaglandins, phytoprostanes and 12-oxo phytodienoic acid (OPDA), activate detoxification responses in plants and animals. However, the pathways leading to the activation of defense reactions related to abiotic or biotic stress as a function of RES formation, accumulation or treatment are poorly understood in plants. Here, the thiol-modification of proteins, including the RES-activated basic region/leucine zipper transcription factor TGA2, was studied. TGA2 contains a single cysteine residue (Cys186) that was covalently modified by reactive cyclopentenones but not required for induction of detoxification genes in response to OPDA or prostaglandin A1. Activation of the glutathione-S-transferase 6 (GST6) promoter was responsive to cyclopentenones but not to unreactive cyclopentanones, including jasmonic acid suggesting that thiol reactivity of RES is important to activate the TGA2-dependent signaling pathway resulting in GST6 activation We show that RES modify thiols in numerous proteins in vivo, however, thiol reactivity alone appears not to be sufficient for biological activity as demonstrated by the failure of several membrane permeable thiol reactive reagents to activate the GST6 promoter.Peer reviewedFinal Published versio
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