IEEE Vehicular Technology Conference | Year: 2014
This paper presents a multi-directive antenna for point-to-multipoint line-of-sight (LOS) communications. Based on an Electromagnetic Crystal (EC) structure, the proposed antenna is able to provide several simultaneous directive beams in different directions at different frequencies. Thus by conveniently disposing the different communication points in the space and allowing them to communicate at different frequencies, a high performance network can be obtained by using a single antenna. To study the antenna performance, both theoretical analysis and numerical simulations are presented and validated by experimental results. andcopy; 2014 IEEE.
Rahman M.M.,Universiteandacute |
Separation and Purification Technology | Year: 2011
The use of solid support in DNA separation from biological mixtures for diagnostics offers great potential for developing versatile separating tools. Although different polymer materials have been developed and studied for DNA separation, the application of such non-magnetic particles for DNA separation has remained limited. In this work, we describe the adsorption and desorption behavior of DNA on the temperature sensitive poly(N-isopropylacrylamide-co- aminoethylmethacrylate) (PNIPAM-co-AEMH) coated magnetic particles. Submicron sized temperature responsive magnetic/PDVB/P (NIPAM/AEMH/MBA) hybrid particles were prepared by a precipitation polymerization of NIPAM in the presence of previously prepared divinylbenzene (DVB) cross-linked magnetic particles as seed. Wherein, N,N-methylenebisacrylamide (MBA), aminoethylmethacrylate hydrochloride (AEMH) and 2,2'-azobis (2-methylpropionamidine) dihydrochloride (V-50) were used as a crosslinker, functional monomer and initiator respectively. The amino (-NH 2) functional groups derived from AEMH and V-50 are able to be cationic charged (-NH + 3 ) by being protonated and can interact electrostatically with negatively charged DNA. The adsorption and desorption behavior of Herring Sperm DNA onto these functional magnetic particles were investigated as a function of pH, temperature, time and ionic strength. Interestingly, it was found that there is a significant effect of temperature on the DNA adsorption onto these magnetic particles. The results obtained indicate that the maximum amount of DNA adsorption was found at lower salt concentration, acidic pH condition and below the volume phase transition temperature (VPTT) of the PNIPAM shell. The highest desorption was found at higher salt concentration in basic pH and above the VPTT (40 °C) temperature. The temperature responsive magnetic particles and procedure described here can be used in microsystem separation technology for nucleic acid extraction, purification and concentration. © 2011 Elsevier B.V. All rights reserved.
Gibbs M.,Universiteandacute |
Breuker C.J.,Oxford Brookes University |
Van Dyck H.,Universiteandacute
Physiological Entomology | Year: 2010
As a result of increased habitat fragmentation in anthropogenic landscapes, flying insects may be required to travel over larger distances in search of resources such as suitable host plants for oviposition. The oögenesis-flight syndrome hypothesis predicts that physiological constraints caused by an overlap in the resources used by thoracic muscles during flight and during oögenesis (e.g. carbohydrates, lipids and water) result in a resource trade-off, with any resources used during flight no longer available for reproduction. Increased flight costs could therefore potentially result in a decrease in maternal provisioning of eggs. In the present study, the speckled wood butterfly Pararge aegeria (L.) is used to investigate whether increased flight during oviposition results in changes in maternal investment in eggs and whether this contributes to variation in the development of offspring in subsequent life stages. Forcing females to fly during oviposition directly influences egg size and embryonic development time, and indirectly influences (through changes in egg size) egg hatching success and larval development time. These effects are mediated through 'selfish maternal effects', with mothers forced to fly maximizing their fecundity at the expense of investment to individual egg size. The present study demonstrates that a change in maternal provisioning as a result of increased flight during oviposition has the potential to exert nongenetic cross-generational fitness effects in P. aegeria. This could have important consequences for population dynamics, particularly in fragmented anthropogenic landscapes. © 2009 The Authors. Journal compilation © 2009 The Royal Entomological Society.
Razakamanarivo R.H.,Universiteandacute |
Grinand C.,Montpellier SupAgro |
Razafindrakoto M.A.,Universiteandacute |
Bernoux M.,Montpellier SupAgro |
Albrecht A.,Montpellier SupAgro
Geoderma | Year: 2011
Recent concerns about global warming have resulted in more concerted studies on quantification and modeling of carbon (C) storage in different ecosystems. The aim of this study was to assess and map the carbon stocks in above (ABG), below-ground (BLG) biomass and soil organic carbon contained in the 30centimeter top-layer (SOC) in coppices of eucalyptus plantations in the central highlands of Madagascar in an area of 1590ha. Relationships between C stock and various biophysical (stool or shoot stockings and ages, circumferences) and spatial (elevation, slope, and soil type) factors that may affect C storage within each pool were investigated. Three different modeling techniques were tested and compared for various factor sets: (i) simple linear regression (SLM), (ii) multiple linear (MLM) models and, (iii) boosted regression tree (BRT) models. Weights of the factors in the respective model were analyzed for the three pool-specific models that produced the highest accuracy measurement. A regional spatial prediction of carbon stocks was performed using spatial layers derived from a digital elevation model, remote sensing imagery and expert knowledge. Results showed that BRT had the best predictive capacity for C stocks compared with the linear regression models. Elevation and slope were found to be the most relevant predictors for modeling C stock in each pool, and mainly for the SOC. A factor representing circumferences of stools and their stocking (stools.ha-1) largely influenced BLG. Shoot circumference at breast height and shoot age were the best factors for ABG fitting. Accuracy assessment carried out using coefficient of determination (R2) and ratio of standard deviation to prediction error (RPD) showed satisfactory results, with 0.74 and 1.95 for AGB, 0.85 and 2.59 for BLG, and 0.61 and 1.6 for SOC respectively. Application of the best fitted models with spatial explanatory factors allowed to map and estimate C contained within each pool: 32andplusmn;13Gg C for ABG, 67andplusmn;15Gg C for BLG and, 139andplusmn;36Gg C for SOC (1Gg=109g). A total of 238andplusmn;40Gg C was obtained for the entire study area by combining the three C maps. Despite their relatively low predictive quality, models and C maps produced herein provided relevant reference values of C storage under plantation ecosystems in Madagascar. This study contributed to the reducing of uncertainty related to C monitoring and baseline definition in managed terrestrial ecosystem. andcopy; 2011 Elsevier B.V.
Meunier A.,University Pierre and Marie Curie |
Bretou M.,Universiteandacute |
Darchen F.,Universiteandacute |
Guille Collignon M.,University Pierre and Marie Curie |
And 2 more authors.
Electrochimica Acta | Year: 2014
Amperometry at ultramicroelectrodes is nowadays a routine analytical technique for quantitative real-time monitoring of vesicular exocytosis at single cell levels. The method performance and ease of application stem from the fact that it simply involves an electrochemical oxidation at a microelectrode surface of neurotransmitters released by a given cell. The exocytotic fluxes are thus converted into a current and appear as a succession of amperometric spikes, whose frequency and shapes are particularly informative about the dynamics of the release process, while their integrals give a direct measure of the quantity of molecules released. In this article, we wish to evaluate and describe the amperometric detection of exocytotic release by BON cells, a cell line derived from a metastatic human carcinoid tumor of the pancreas and recently involved in combined approaches of exocytosis (particularly fluorescence/electrochemistry). The whole exocytotic activity (frequency, spike magnitude) of BON cells is rather weak by comparison with those observed with others cell models like chromaffin cells but remain suitable for amperometric investigations. andcopy; 2013 Elsevier Ltd.©2013 Elsevier Ltd. All rights reserved.
Smirani S.,CEA Saclay Nuclear Research Center |
Kamoun M.,CEA Saclay Nuclear Research Center |
Sarkiss M.,CEA Saclay Nuclear Research Center |
Zaidi A.,Universiteandacute |
International Conference on Advanced Technologies for Communications | Year: 2012
A Two-Way Relay Channel (TWRC) in which duplex transmission between two users via a relay station is considered. A physical layer network coding strategy based on compress-and-forward relaying scheme for the TWRC is proposed. In the underlying coding strategy, we use nested lattices for Wyner-Ziv coding and decoding. The relay uses the weaker side information available at the receivers from the first transmission phase to broadcast a common quantized version of its received signal. We characterize the achievable rate region of the presented scheme. Then we show that lattice codes can achieve random coding rates. © 2012 IEEE.
Desrochers N.,Universiteandacute |
Laplante A.,Universiteandacute |
Quan-Haase A.,University of Western Ontario |
Martin K.,University of Western Ontario |
And 2 more authors.
Proceedings of the ASIST Annual Meeting | Year: 2013
Social tagging has become a common practice across a variety of platforms on the Web. In this panel, we propose to start with one title, Casino Royale, a James Bond novel by Ian Fleming, and the other cultural products that emanated from it (e.g., two movies, one song, visuals and images, articles and blog posts) to explore social tagging practices and other user-generated content in a variety of different platforms. Goodreads, Last.fm, WordPress, Flickr and various library discovery systems will be used to expose the connections users establish between and among cultural products as well as to compare what tagging yields in different platforms. The results will be situated within the context of broader studies being performed by the panelists and audience members will be asked to contribute material for real-time searches.
Adler M.,University of Kentucky |
Milojevic S.,Indiana University Bloomington |
Rogers C.,ISchool at UBC |
Tennis J.T.,University of Washington |
And 2 more authors.
Proceedings of the ASIST Annual Meeting | Year: 2013
The panel explores the theoretical, methodological, and design aspects of the temporal dimension in the study of knowledge creation and representation and offers insights in both the challenges and the promising future directions. The goal of the panel is to start a collaborative discussion around a number of important themes.
Aujoulat I.,Universiteandacute |
Janssen M.,Universiteandacute |
Libion F.,Universiteandacute |
Charles A.-S.,Universiteandacute |
And 8 more authors.
Qualitative Health Research | Year: 2014
The transition from parent-controlled care to self-managed care represents an important challenge for adolescents with chronic conditions. We sought to gain a deeper understanding of the factors influencing the internalization of motivation to self-care in adolescent liver transplant recipients. We conducted a qualitative study using in-depth interviews with 18 young patients. We triangulated the data collected from the patients with data from parents and health care providers, and used an inductive approach to analyze the data. Our results illustrate three interrelated challenges that impact on young patients' motivation to self-care: (a) the cognitive challenge of fully understanding one's condition and personal health risks; (b) the behavioral challenge of developing independence regarding self-management issues; and (c) the psychological challenge of building a sense of self-ownership and purpose. The latter involves overcoming the trauma of survival and coming to terms with feelings of obligation, two challenges inherent to transplantation that warrant further investigation. © The Author(s) 2014.
Early transcriptomic changes induced by magnesium deficiency in Arabidopsis thaliana reveal the alteration of circadian clock gene expression in roots and the triggering of abscisic acid-responsive genes
Hermans C.,Universiteandacute |
Vuylsteke M.,Vlaams Institute for Biotechnology |
Vuylsteke M.,Ghent University |
Coppens F.,Vlaams Institute for Biotechnology |
And 5 more authors.
New Phytologist | Year: 2010
Summary: •Plant growth and development ultimately depend on environmental variables such as the availability of essential minerals. Unravelling how nutrients affect gene expression will help to understand how they regulate plant growth.•This study reports the early transcriptomic response to magnesium (Mg) deprivation in Arabidopsis. Whole-genome transcriptome was studied in the roots and young mature leaves 4, 8 and 28 h after the removal of Mg from the nutrient solution.•The highest number of regulated genes was first observed in the roots. Contrary to other mineral deficiencies, Mg depletion did not induce a higher expression of annotated genes in Mg uptake. Remarkable responses include the perturbation of the central oscillator of the circadian clock in roots and the triggering of abscisic acid (ABA) signalling, with half of the up-regulated Mg genes in leaves being ABA-responsive. However, no change in ABA content was observed.•The specificity of the response of some Mg-regulated genes was challenged by studying their expression after other mineral deficiencies and environmental stresses. The possibility to develop markers for Mg incipient deficiency is discussed here. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).