Influence du changement climatique sur la diversité inter et intra-spécifique des plantes cultivées à Tougou au nord du Burkina Faso

L’objectif de l’étude est d’évaluer la diversité taxonomique et la variabilité inter et intra-spécifique des plantes cultivées non spontanées dans un contexte de changement climatique. Les données sont collectées à l’aide d’une enquête au près de 75 producteurs menée suivant des interviews semi-structurées. Les résultats ont révélé l’existence de 122 écotypes appartenant à 49 espèces, 39 genres et 22 familles. La diversité interspécifique représentait 73% de la diversité des plantes cultivées au plan national. La variabilité intraspécifique était faible comparée à la variabilité au plan national. Elle était plus élevée chez les céréales et les cultures potagères pluviales avec 2 à 10 écotypes par espèce contre 1 à 3 écotypes par espèce chez les cultures maraîchères. Les écotypes ayant un cycle de plus de 90 jours représentant 10,5% de l’ensemble des écotypes recensés, sont menacés de disparition à cause du changement climatique. Une stratégie de collecte, de conservation, d’amélioration et de promotion de ces ressources ainsi que la restauration des écosystèmes dégradés s’avèrent nécessaire pour le maintien de la phytodiversité cultivée.Mots clés: Burkina Faso, agro biodiversité, écotype, espèces menacées, conservatio

Relational climates moderate the effect of openness to experience on knowledge hiding:A two-country multi-level study

Purpose:  Understanding employee knowledge hiding behavior can serve organizations in better implementing knowledge management practices. The purpose of this study is to investigate how personality and work climate influence knowledge hiding, by examining the respective roles of openness to experience and relational (specifically, communal sharing and market pricing) climates.  Design/methodology/approach:  Multilevel modeling was used with two distinct samples, one from Vietnam with 119 employees in 20 teams and one from The Netherlands with 136 employees in 32 teams.  Findings:  In both samples, the hypothesized direct relationship between openness and knowledge hiding was not found. In the Vietnamese sample, only the moderating effect of market pricing climate was confirmed; in the Dutch sample, only the moderating effect of communal sharing climate was confirmed. The findings of the Vietnamese sample suggest that people with a high sense of openness to experience hide knowledge less under low market pricing climate. In the Dutch sample, people with high openness to experience hide knowledge less under high communal sharing climate. The authors conclude that, in comparison with personality, climate plays a stronger role in predicting knowledge hiding behavior.  Research limitations/implications:  Small sample size and self-reported data might limit the generalizability of this study’s results.  Practical implications:  The paper highlights how organizational context (relational climate) needs to be taken into account in predicting how personality (openness to experience) affects knowledge hiding.  Originality/value:  This paper contributes to a better understanding of the knowledge hiding construct by extending the set of known antecedents and exploring the organizational context in which such phenomena happen

WFPC2 Images of the Central Regions of Early-Type Galaxies - I. The Data

We present high resolution R-band images of the central regions of 67 early-type galaxies obtained with the Wide Field and Planetary Camera 2 (WFPC2) aboard the Hubble Space Telescope (HST). Our sample strikingly confirms the complex morphologies of the central regions of early-type galaxies. In particular, we detect dust in 43 percent of all galaxies, and evidence for embedded stellar disks in a remarkably large fraction of 51 percent. In 14 of those galaxies the disk-like structures are misaligned with the main galaxy, suggesting that they correspond to stellar bars in S0 galaxies. We analyze the luminosity profiles of the galaxies in our sample, and classify galaxies according to their central cusp slope. To a large extent we confirm the clear dichotomy found in previous HST surveys: bright, boxy ellipticals with shallow inner cusps (`core' galaxies) on one hand and faint, disky ellipticals with steep central cusps (`power-law' galaxies) on the other hand. The advantages and shortcomings of classification schemes utilizing the extrapolated central cusp slope are discussed, and it is shown that this cusp slope might be an inadequate representation for galaxies whose luminosity profile slope changes smoothly with radius rather than resembling a broken power-law. In fact, we find evidence for an `intermediate' class of galaxies, that cannot unambiguously be classified as either core or power-law galaxies, and which have central cusp slopes and absolute magnitudes intermediate between those of core and power-law galaxies.Comment: 44 pages, 7 Postscript figures. Accepted for publication in the Astronomical Journal. The associated Appendix with figures of luminosity profiles, contour plots and isophotal parameters for all galaxies is available at http://www.astro.washington.edu/rest/centralpro

The Road to 6G: Ten Physical Layer Challenges for Communications Engineers

While the deployment of 5G cellular systems will continue well in to the next decade, much interest is already being generated towards technologies that will underlie its successor, 6G. Undeniably, 5G will have transformative impact on the way we live and communicate, yet, it is still far away from supporting the Internet-of-Everything (IoE), where upwards of a million devices per $\textrm{km}^3$ (both terrestrial and aerial) will require ubiquitous, reliable, low-latency connectivity. This article looks at some of the fundamental problems that pertain to key physical layer enablers for 6G. This includes highlighting challenges related to intelligent reflecting surfaces, cell-free massive MIMO and THz communications. Our analysis covers theoretical modeling challenges, hardware implementation issues and scalability among others. The article concludes by delineating the critical role of signal processing in the new era for wireless communications.Comment: IEEE Communications Magazine, Accepte

Evaluation of different methods in quantification of manufacturing defects

In the context of manufacturing defects, our interest is the calculation methodologies that are used to quantify these defects. The manufacturing defects can be divided into two categories: machining defects and positioning defects. A double measurement method is principally used to quantify separately machining and positioning defect. The first measurement is operated inside a machine tool just after the final cutting step. The second measurement is realised outside of the machine tool (e.g. on a coordinate measuring machine - CMM). However, data processing method and precision between two different machines are different. Consequently, the measurement results obtained from these machines may be not comparable to quantify precisely the manufacturing defects. Several solutions are proposed and analysed in this paper to estimate comparable capability of the measurement results obtained by the two different measurement mean

Mobile measurements of microclimatic variables through the central area of Singapore: An analysis from the pedestrian perspective

High-density cities, such as Singapore, are currently facing the urban heat island (UHI) effect, a phenomenon that leads to higher air and surface temperatures within the urban area in comparison to the surroundings and is one of the most critical anthropogenic climate change-related environmental issues for contemporary high-density cities. This study aims to investigate the effect of different urban morphologies such as high-rise and low-rise buildings, green areas, and water bodies on the urban microclimate in Singapore. Mobile measurements taken from a pedestrian perspective were conducted for the first time in the central area of Singapore to explore the severity of the UHI effect through distinctive urban morphologies. The Sky View Factor (SVF) was the metric used to quantify these characteristics. During daytime, the air temperature was higher when SVF increased, except for the water body area. Shading showed to be an important factor to decreasing air temperature in the tropics. Reductions by up to 4.5 ºC were observed due to the buildings shading during daytime, while the cooling effect of vegetation reduced the air temperature by up to 4 ºC during the daytime and 1 ºC at night-time. Thus, this study revealed a strong relationship between the decrease in air temperature and greenery coverage in the city. Therefore, understanding the relationship between urban morphology and microclimate conditions may better drive sustainable urban planning and development in the tropics. Finally, it was demonstrated the importance of using mobile monitoring to retrieve granular data that allows identifying specific environmental issues on a hyperlocal scale, which would not be recognised through other monitoring techniques.This work was partially funded by the Ministerio de Ciencia, Innovación y Universidades de España (RTI2018-093849-B-C31 - MCIU/AEI/FEDER, UE) and by the Ministerio de Ciencia, Innovación y Universidades - Agencia Estatal de Investigación (AEI) (RED2018-102431-T). The authors would like to thank the Catalan Government for the quality accreditation given to their research group (2017 SGR 1537). GREiA is certified agent TECNIO in the category of technology developers from the Government of Catalonia. This work is partially supported by ICREA under the ICREA Academia programme

Ramial wood amendments (Piliostigma reticulatum) mitigate degradation of tropical soils but do not replenish nutrient exports

Restoring degraded soils to support food production is a major challenge for West African smallholders who have developed local innovations to counter further degradation. The objective of this study was to evaluate a local farmer's technique that uses ramial wood (RW) as soil amendment (Piliostigma reticulatum shrub). Three treatments were applied in an experimental plot in Burkina Faso: control (no amendment), low RW (3 Mg fresh mass·ha−1·yr−1), and high RW (12 Mg fresh mass·ha−1·yr−1). RW was chipped to <5‐cm pieces and either buried or mulched. Topsoil carbon (C), nitrogen (N), and phosphorus (P) in control and low‐RW treatments declined after 7 years of continuous sorghum cultivation. Use of high‐RW amendment stabilized soil C content while N and P declined, thus not replenishing nutrient exports. Net contribution to soil C in the layer measuring 0–15 cm was 15% of the applied C in the high‐RW amendments. Although biomass and grain yields were higher in high‐RW treatments, crop productivity declined throughout the experiment for all treatments. Termite casts on RW treatments evidenced the potential role of wood‐foraging termites in diluting the impact of RW on soil fertility build‐up and soil water content. We conclude that mitigating soil degradation under semiarid conditions in Burkina Faso would require large amounts of woody amendments, particularly if the level of termite activity is high. Additional nutrient sources would be needed to compensate for removal in exported products so that biomass and grain production can be stabilized or increased.Estación Experimental Agropecuaria BarilocheFil: Félix, Georges F. Wageningen University. Farming Systems Ecology; HolandaFil: Clermont-Dauphin, Cathy. Montpellier SupAgro- Centre de Coopération Internationale en Recherche Agronomique pour le Développement-Institut National de la Recherche Agronomique. Eco&Sols; FranciaFil: Hien, Edmond. Laboratoire Mixte International. Intensification Ecologique des Sols Cultivés en Afrique de l'Ouest; Burkina FasoFil: Groot, Jeroen C.J. Wageningen University. Farming Systems Ecology; HolandaFil: Penche, Aurelien. Laboratoire Mixte International. Intensification Ecologique des Sols Cultivés en Afrique de l'Ouest; Burkina FasoFil: Barthès, Bernard G. Universidad Montpellier; FranciaFil: Manlay, Raphaël J. AgroParisTech; FranciaFil: Tittonell, Pablo Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche; ArgentinaFil: Cournac, Laurent. Montpellier SupAgro- Centre de Coopération Internationale en Recherche Agronomique pour le Développement-Institut National de la Recherche Agronomique. Eco&Sols; Franci