ELABORATING INNOVATIVE SOLUTIONS WITH EXPERTS USING A MULTICRITERIA EVALUATION TOOL. THE CASE OF SOIL BORNE DISEASE CONTROL IN MARKETGARDENING CROPPING SYSTEMS

International audienceMarket-gardening cropping systems in protected cultivation are very sensitive to soil-borne pests and diseases. Their productivity used to rely on pesticides, but alternative systems have now to be found for environmental, societal and health reasons. Many cultural techniques are known to provide some control of soilborne diseases, but are only partially efficient. The aim of the project is to design alternative systems with professionals, by improving the efficiency of the present techniques and/or imagining more innovative systems. The research project takes place in two steps. The first one consists in building a tool to assess the resistance or resilience of a given cropping system to soil-borne pests; the second one consists in using the tool with professionals in order to build alternative cropping and farming systems in cooperation. The model built for evaluation is a qualitative multicriteria tool. As scientific knowledge is not available for each technique or combination of techniques, empirical knowledge collected from growers and technical advisers is used to fill the gaps. The model is already built for root-knot nematodes and under construction for the other fungi. The second step will consist in using the tool with technical advisers and growers to redesign cropping systems and select the promising ones that should be put into trial in R&D stations. Co-building farming systems with stakeholders appears as an absolute necessity, to imagine solutions both efficient and acceptable for growers. The presentation will enable to discuss how combining expert and scientific knowledge may not only fill the knowledge gap, but also enable to build innovative solutions thanks to the diversity of experts' standpoints

Nutrients composition of calyces and seeds of three Roselle (Hibiscus sabdariffa L.) ecotypes from Niger

The chemical composition of calyces and seeds of three ecotypes of Roselle from Niger was compared. The results indicate that calcium (Ca), potassium (K), sodium (Na), magnesium (Mg) and protein contents in calyces are significantly different (P<0.005) among ecotypes. The highest concentrations of K, Na, Mg and protein in calyces were recorded for ecotype E7 (35.66, 3.40, 6.01 and 101 mg/g d.w., respectively). Ecotype E9 had the highest Ca content in calyces (34.41 mg/g d.w.); while E3 and E7 had similar and lower contents. The protein content in calyces for E9 (52 mg/g d.w.) was approximately halved compared to those of E3 and E7. For all ecotypes, the concentrations of Ca, K, Mn, Na and Fe in the calyces were higher compared to those in the seeds. In contrast, P content was higher in seeds. The highest K, Na, Mg and P concentrations in seeds were registered for E7 and the lowest ones for E9. Ecotypes E3 and E9 recorded higher and similar Cu, Fe and Mn contents in calyces and in seeds compared to E7. The highest Zn concentrations in seeds were obtained for E3 and E7.Keywords: Niger, Roselle, seeds, calyces, protein, composition, micronutrients, macronutrientsAfrican Journal of Biotechnology Vol. 12(26), pp. 4174-417

Entanglement distance for arbitrary M -qudit hybrid systems

This is the final version. Available from the American Physical Society via the DOI in this recordThe achievement of quantum supremacy boosted the need for a robust medium of quantum information. In this task, higher-dimensional qudits show remarkable noise tolerance and enhanced security for quantum key distribution applications. However, to exploit the advantages of such states, we need a thorough characterisation of their entanglement. Here, we propose a measure of entanglement which can be computed either for pure and mixed states of a $M$-qudit hybrid system. The entanglement measure is based on a distance deriving from an adapted application of the Fubini-Study metric. This measure is invariant under local unitary transformations and has an explicit computable expression that we derive. In the specific case of $M$-qubit systems, the measure assumes the physical interpretation of an obstacle to the minimum distance between infinitesimally close states. Finally, we quantify the robustness of entanglement of a state through the eigenvalues analysis of the metric tensor associated with it.QuantERA ERA-NET Co-fundEngineering and Physical Sciences Research Council (EPSRC

Structural Analysis of Nano Core PCF With Fused Cladding for Supercontinuum Generation in 6G Networks

The Sixth Generation (6G) networks have identified the use of frequency range between 95 GHz and 3 THz with a targeted data rate of 1 Terabytes/second at the access network for holographic video applications. As is demands broadening of spectrum at the core network, this paper proposes a Supercontinuum Generation (SCG) through photonic crystal fiber (PCF) as it provides excellent broadening of the optical spectrum. Discussed in the paper is supercontinuum generation at high pumping power as per the standards specified by the International Telecommunications Union. The proposed PCF is designed with silicon nanocrystal core and the cladding microstructures is arranged in a fusion approach to effectively optimize the optical parameters such as dispersion, nonlinearity, birefringence, group-velocity dispersion, and confinement loss. The fused cladding comprises of a flower-cladding assembly in which air-holes arrangement is inspired from petals in a pleated structure. Such arrangement is shown here to provide high nonlinearity and negative dispersion for high power supercontinuum generation. The novel nanocore assembly with improved structural constraints delivers a non-linearity of 6.37 × 106 W−1 km−1 and a negative dispersion of −142.1 (ps/nm-km) at 1,550 nm. Moreover, a supercontinuum spectrum is generated using different pulse widths ranging from 350 to 650 ps with 25 kW pump power for PCF lengths of 10 and 15 mm

A Comprehensive Survey on 'Various Decoupling Mechanisms with Focus on Metamaterial and Metasurface Principles Applicable to SAR and MIMO Antenna Systems'

Nowadays synthetic aperture radar (SAR) and multiple-input-multiple-output (MIMO) antenna systems with the capability to radiate waves in more than one pattern and polarization are playing a key role in modern telecommunication and radar systems. This is possible with the use of antenna arrays as they offer advantages of high gain and beamforming capability, which can be utilized for controlling radiation pattern for electromagnetic (EM) interference immunity in wireless systems. However, with the growing demand for compact array antennas, the physical footprint of the arrays needs to be smaller and the consequent of this is severe degradation in the performance of the array resulting from strong mutual-coupling and crosstalk effects between adjacent radiating elements. This review presents a detailed systematic and theoretical study of various mutual-coupling suppression (decoupling) techniques with a strong focus on metamaterial (MTM) and metasurface (MTS) approaches. While the performance of systems employing antenna arrays can be enhanced by calibrating out the interferences digitally, however it is more efficient to apply decoupling techniques at the antenna itself. Previously various simple and cost-effective approaches have been demonstrated to effectively suppress unwanted mutual-coupling in arrays. Such techniques include the use of defected ground structure (DGS), parasitic or slot element, dielectric resonator antenna (DRA), complementary split-ring resonators (CSRR), decoupling networks, P.I.N or varactor diodes, electromagnetic bandgap (EBG) structures, etc. In this review, it is shown that the mutual-coupling reduction methods inspired By MTM and MTS concepts can provide a higher level of isolation between neighbouring radiating elements using easily realizable and cost-effective decoupling configurations that have negligible consequence on the arrays characteristics such as bandwidth, gain and radiation efficiency, and physical footprint

High-isolation antenna array using SIW and realized with a graphene layer for sub-terahertz wireless applications

This paper presents the results of a study on developing an effective technique to increase the performance characteristics of antenna arrays for sub-THz integrated circuit applications. This is essential to compensate the limited power available from sub-THz sources. Although conventional array structures can provide a solution to enhance the radiation-gain performance however in the case of small-sized array structures the radiation properties can be adversely affected by mutual coupling that exists between the radiating elements. It is demonstrated here the effectiveness of using SIW technology to suppress surface wave propagations and near field mutual coupling effects. Prototype of 2x3 antenna arrays were designed and constructed on a polyimide dielectric substrate with thickness of 125 mu m for operation across 0.19-0.20 THz. The dimensions of the array were 20x13.5x0.125 mm(3). Metallization of the antenna was coated with 500 nm layer of Graphene. With the proposed technique the isolation between the radiating elements was improved on average by 22.5 dB compared to a reference array antenna with no SIW isolation. The performance of the array was enhanced by transforming the patch to exhibit metamaterial characteristics. This was achieved by embedding the patch antennas in the array with sub-wavelength slots. Compared to the reference array the metamaterial inspired structure exhibits improvement in isolation, radiation gain and efficiency on average by 28 dB, 6.3 dBi, and 34%, respectively. These results show the viability of proposed approach in developing antenna arrays for application in sub-THz integrated circuits

Design of a Planar Sensor Based on Split-Ring Resonators for Non-Invasive Permittivity Measurement

The permittivity of a material is an important parameter to characterize the degree of polarization of a material and identify components and impurities. This paper presents a non-invasive measurement technique to characterize materials in terms of their permittivity based on a modified metamaterial unit-cell sensor. The sensor consists of a complementary split-ring resonator (C-SRR), but its fringe electric field is contained with a conductive shield to intensify the normal component of the electric field. It is shown that by tightly electromagnetically coupling opposite sides of the unit-cell sensor to the input/output microstrip feedlines, two distinct resonant modes are excited. Perturbation of the fundamental mode is exploited here for determining the permittivity of materials. The sensitivity of the modified metamaterial unit-cell sensor is enhanced four-fold by using it to construct a tri-composite split-ring resonator (TC-SRR). The measured results confirm that the proposed technique provides an accurate and inexpensive solution to determine the permittivity of materials