Dutch Focus Groups results. TR 3.54 Interactions with citizens and consumers at local scale

As part of the Endure project, funded by the EU Sixth Framework Programme, two focus group sessions were carried out in January 2010 in the Netherlands. Aim of these focus group sessions was to understand the believes, associations and attitudes people have concerning the use of pesticides and integrated pest management (IPM) in regard to apples and pears. In total 15 people participated in the focus group session and participants were heterogeneous in gender, age and background. They all bought apples and most of them visited farms are farmers markets

Characterizing CDMA downlink feasibility via effective interference

This paper models and analyses downlink power assignment feasibility in Code Division Multiple Access (CDMA) mobile networks. By discretizing the area into small segments, the power requirements are characterized via a matrix representation that separates user and system characteristics. We obtain a closed-form analytical expression of the so-called Perron-Frobenius eigenvalue of that matrix, which provides a quick assessment of the feasibility of the power assignment for each distribution of calls over the segments. Although the obtained relation is non-linear, it basically provides an effective interference characterisation of downlink feasibility. Our results allow for a fast evaluation of outage and blocking probabilities, and enable a quick evaluation of feasibility that may be used for Call Acceptance Control. \u

Direct electronic measurement of Peltier cooling and heating in graphene

Thermoelectric effects allow the generation of electrical power from waste heat and the electrical control of cooling and heating. Remarkably, these effects are also highly sensitive to the asymmetry in the density of states around the Fermi energy and can therefore be exploited as probes of distortions in the electronic structure at the nanoscale. Here we consider two-dimensional graphene as an excellent nanoscale carbon material for exploring the interaction between electronic and thermal transport phenomena, by presenting a direct and quantitative measurement of the Peltier component to electronic cooling and heating in graphene. Thanks to an architecture including nanoscale thermometers, we detected Peltier component modulation of up to 15 mK for currents of 20 $\mu$A at room temperature and observed a full reversal between Peltier cooling and heating for electron and hole regimes. This fundamental thermodynamic property is a complementary tool for the study of nanoscale thermoelectric transport in two-dimensional materials.Comment: Final version published in Nature Communications under a Creative Commons Attribution 4.0 International Licens

Changes in the secretory profile of NSCLC-associated fibroblasts after ablative radiotherapy: potential impact on angiogenesis and tumor growth

In the context of radiotherapy, collateral effects of ablative ionizing radiation (AIR) on stromal components of tumors remains understudied. In this work, cancer-associated fibroblasts (CAFs) isolated from freshly resected human lung tumors were exposed to AIR (1x18Gy) and analyzed for their release of paracrine factors. Inflammatory mediators and regulators of angiogenesis and tumor growth were analyzed by multiplex protein assays in conditioned medium (CM) from irradiated and non-irradiated CAFs. Additionally, the profile of secreted proteins was examined by proteomics. In functional assays, effects of CAF-CM on proliferative and migratory capacity of lung tumor cells (H-520/H-522) and endothelial cells (HUVECs), and on the tube-forming capacity of endothelial cells was assessed. Our data show that exposure of CAFs to ablative doses of ionizing radiation results in a) down-regulated release of angiogenic factors SDF-1, angiopoietin and thrombospondin-2; b) up-regulated release of growth factor bFGF from most donors, and c) unaffected expression-levels of HGF and inflammatory mediators IL-6, IL-8, IL-1ƒÒ and TNF-£. Conditioned medium from irradiated and control CAFs did not affect differently the proliferative or migratory capacity of tumor cells (H-520/H-522), whereas migratory capacity of endothelial HUVEC cells was partially reduced in the presence of irradiated CAF conditioned medium. Overall we conclude that AIR mediates a transformation on the secretory profile of CAFs that could influence the behavior of other cells in the tumor tissue and hence guide to some extent therapeutic outcomes. The downstream consequences of the changes observed in this study merits further investigations

Role of product characteristics for the adoption of fruit and fruit product innovations

The aim of this study was the identification of those product characteristics that are important for the adoption of fruit and fruit product innovations by consumers. Sixteen focus group discussions were held in four European countries (Greece, The Netherlands, Poland, and Spain). Different aspects of six innovative fruit products were discussed, revealing those characteristics that were important for the adoption of each of them. It was observed that the participants did not perceive fruit innovations as a homogenous group, but assigned them to different groups, which led to a number of categories of fruit innovation. Three categories concerned the level of preparation of fruit. These were fresh, prepared, and processed fruit product innovations. Another two categories, radical and evolutionary innovations, related to the level of novelty of the fruit innovation. Characteristics important for the adoption of each of these categories are given.The results will be used for further, more quantitative, research

Spin transport in graphene nanostructures

Graphene is an interesting material for spintronics, showing long spin relaxation lengths even at room temperature. For future spintronic devices it is important to understand the behavior of the spins and the limitations for spin transport in structures where the dimensions are smaller than the spin relaxation length. However, the study of spin injection and transport in graphene nanostructures is highly unexplored. Here we study the spin injection and relaxation in nanostructured graphene with dimensions smaller than the spin relaxation length. For graphene nanoislands, where the edge length to area ratio is much higher than for standard devices, we show that enhanced spin-flip processes at the edges do not seem to play a major role in the spin relaxation. On the other hand, contact induced spin relaxation has a much more dramatic effect for these low dimensional structures. By studying the nonlocal spin transport through a graphene quantum dot we observe that the obtained values for spin relaxation are dominated by the connecting graphene islands and not by the quantum dot itself. Using a simple model we argue that future nonlocal Hanle precession measurements can obtain a more significant value for the spin relaxation time for the quantum dot by using high spin polarization contacts in combination with low tunneling rates

Entropy-based analysis of the number partitioning problem

In this paper we apply the multicanonical method of statistical physics on the number-partitioning problem (NPP). This problem is a basic NP-hard problem from computer science, and can be formulated as a spin-glass problem. We compute the spectral degeneracy, which gives us information about the number of solutions for a given cost $E$ and cardinality $m$. We also study an extension of this problem for $Q$ partitions. We show that a fundamental difference on the spectral degeneracy of the generalized ($Q>2$) NPP exists, which could explain why it is so difficult to find good solutions for this case. The information obtained with the multicanonical method can be very useful on the construction of new algorithms.Comment: 6 pages, 4 figure

Theory of the striped superconductor

We define a distinct phase of matter, a "pair density wave" (PDW), in which the superconducting order parameter $\phi$ varies periodically as a function of position such that when averaged over the center of mass position, all components of $\phi$ vanish identically. Specifically, we study the simplest, unidirectional PDW, the "striped superconductor," which we argue may be at the heart of a number of spectacular experimental anomalies that have been observed in the failed high temperature superconductor, La$_{2-x}$ Ba$_x$CuO$_4$. We present a solvable microscopic model with strong electron-electron interactions which supports a PDW groundstate. We also discuss, at the level of Landau theory, the nature of the coupling between the PDW and other order parameters, and the origins and some consequences of the unusual sensitivity of this state to quenched disorder.Comment: 16 pages, 3 figures, 1 table; Journal ref. adde

An ISFET-based anion sensor for the potentiometric detection of organic acids in liquid chromatography

An ion-selective field effect transistor (ISFET) was applied as a potentiometric detector in liquid chromatography (LC) for the determination of organic acids. The ISFET was prepared by coating the gate insulator of the encapsulated transistor with a poly(vinyl chloride) (PVC) matrix membrane containing methyltridodecylammoniumchloride, which enables the detection of organic anions. The ISFET was tested for its applicability as detector for carboxylic acids in ion-exchange and reversed-phase chromatography. Its analytical characteristics were compared to those of a coated-wire electrode (CWE) and of a conventional type of ion-selective electrode (ISE)