Journal of Next-Generation Research 5.0
Not a member yet
7559 research outputs found
Sort by
Chirality-controlled spontaneous currents in spin-orbit coupled superconducting rings
No full textInternational audienceAt a superconductor interface with a ferromagnetic insulator (FI), the FI acts to induce a local exchange field within the S layer, which in the presence of spin-orbit interaction promotes a phase-modulated superconducting state. Here we demonstrate that within a thin superconducting loop that is partially proximitized by a FI, spontaneous currents form with a magnetization-orientation-dependent chirality with sizable shifts in Little-Parks oscillations. Furthermore, the critical temperature of the loop is also magnetization-orientation-dependent and conversely, the superconducting transition itself may influence the magnetization direction. More generally, the superconducting region above the FI serves as a "phase battery" and so offers a new device concept for superconducting spintronics
Eclogites from the Marun-Keu Complex, Polar Urals, Russia: a record of hot subduction and sub-isothermal exhumation
No full textInternational audienceLenses and boudins of eclogitized and non-metamorphic gabbroic and ultramafic rocks occurring in quartzofeldspathic gneisses and migmatites of the Marun-Keu Complex, Polar Urals, are of central interest for the study of fluid-controlled processes in the subducting continental lithosphere. Petrology and mineral chemistry, combined with multi-equilibrium geothermobarometry and phase-equilibrium modelling, applied to mafic eclogitic rocks show a prograde evolution from c. 685°C, 1.89 GPa and aH2O = 0.6 to c. 745°C, 2.13 GPa and aH2O = 1 followed by near-isothermal decompression down to c. 1.63 GPa. The absence of pre-eclogitic H2O-bearing mineral inclusions in garnet and omphacite suggests that the primary magmatic rocks have not been affected by prograde metamorphism during subduction due to the lack of fluid. We suggest that the Marun-Keu Complex represents a coherent crustal block that experienced the same P–T evolution but provides a metamorphic record of different P–T parameters because of an uneven introduction of aqueous-bearing fluids during subduction and exhumation. The tectonometamorphic history of the Marun-Keu Complex is best attributed to the relatively hot regime of the continental margin subduction beneath an island arc, whereas the blueschist-facies part of the complex towards the north could be related to the closure of the Uralian Ocean
Inter-individual differences in ontogenetic trophic shifts among three marine predators
No full textInternational audienceOntogenetic niche shifts are widespread. However, individual differences in size at birth, morphology, sex, and personalitiescan cause variability in behavior. As such, inherent inter-individual differences within populations may lead to context-dependent changes in behavior with animal body size, which is of concern for understanding population dynamics andoptimizing ecological monitoring. Using stable carbon and nitrogen isotope values from concurrently sampled tissues, wequantified the direction and magnitude of intraspecific variation in trophic shifts among three shark species, and how thesechanged with body size: spurdogs (Squalus spp.) in deep-sea habitats off La Réunion, bull sharks (Carcharhinus leucas) inestuarine habitats of the Florida Everglades, and blacktip reef sharks (Carcharhinus melanopterus) in coral reef ecosystemsof Moorea, French Polynesia. Intraspecific variation in trophic shifts was limited among spurdogs, and decreased with bodysize, while bull sharks exhibited greater individual differences in trophic shifts, but also decreased in variability throughontogeny. In contrast, blacktip reef sharks exhibited increased intraspecific variation in trophic interactions with body size.Variability in trophic interactions and ontogenetic shifts are known to be associated with changes in energetic requirements,but can vary with ecological context. Our results suggest that environmental stability may affect variability within popula-tions, and ecosystems with greater spatial and/or temporal variability in environmental conditions, and those with morediverse food webs may facilitate greater individual differences in trophic interactions, and thus ontogenetic trophic shifts. Inlight of concerns over environmental disturbance, elucidating the contexts that promote or dampen phenotypic variability isinvaluable for predicting population- and community-level responses to environmental changes
Hydrostatic Pressure Helps to Cultivate an Original Anaerobic Bacterium From the Atlantis Massif Subseafloor (IODP Expedition 357): Petrocella atlantisensis gen. nov. sp. nov.
No full textInternational audienceRock-hosted subseafloor habitats are very challenging for life, and current knowledge about microorganisms inhabiting such lithic environments is still limited. This study explored the cultivable microbial diversity in anaerobic enrichment cultures from cores recovered during the International Ocean Discovery Program (IODP) Expedition 357 from the Atlantis Massif (Mid-Atlantic Ridge, 30°N). 16S rRNA gene survey of enrichment cultures grown at 10–25°C and pH 8.5 showed that Firmicutes and Proteobacteria were generally dominant. However, cultivable microbial diversity significantly differed depending on incubation at atmospheric pressure (0.1 MPa), or hydrostatic pressures (HP) mimicking the in situ pressure conditions (8.2 or 14.0 MPa). An original, strictly anaerobic bacterium designated 70B-AT was isolated from core M0070C-3R1 (1150 meter below sea level; 3.5 m below seafloor) only from cultures performed at 14.0 MPa. This strain named Petrocella atlantisensis is a novel species of a new genus within the newly described family Vallitaleaceae (order Clostridiales, phylum Firmicutes). It is a mesophilic, moderately halotolerant and piezophilic chemoorganotroph, able to grow by fermentation of carbohydrates and proteinaceous compounds. Its 3.5 Mb genome contains numerous genes for ABC transporters of sugars and amino acids, and pathways for fermentation of mono- and di-saccharides and amino acids were identified. Genes encoding multimeric [FeFe] hydrogenases and a Rnf complex form the basis to explain hydrogen and energy production in strain 70B-AT. This study outlines the importance of using hydrostatic pressure in culture experiments for isolation and characterization of autochthonous piezophilic microorganisms from subseafloor rocks
Very Low Phytoplankton Diversity in a Tropical Saline-Alkaline Lake, with Co-dominance of Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta)
No full textInternational audienceLake Dziani Dzaha (Mayotte Island, Indian Ocean) is a tropical thalassohaline lake which geochemical and biological conditions make it a unique aquatic ecosystem considered as a modern analogue of Precambrian environments. In the present study, we focused on the diversity of phytoplanktonic communities, which produce very high and stable biomass (mean 2014-2015 = 652 ± 179 μg chlorophyll a L −1). As predicted by classical community ecology paradigms, and as observed in similar environments, a single species is expected to dominate the phytoplanktonic communities. To test this hypothesis, we sampled water column in the deepest part of the lake (18 m) during rainy and dry seasons for two consecutive years. Phytoplanktonic communities were characterized using a combination of metagenomic, microscopy-based and flow cytometry approaches, and we used statistical modeling to identify the environmental factors determining the abundance of dominant organisms. As hypothesized, the overall diversity of the phytoplanktonic communities was very low (15 OTUs), but we observed a co-dominance of two, and not only one, OTUs, viz., Arthrospira fusiformis (Cyanobacteria) and Picocystis salinarum (Chlorophyta). We observed a decrease in the abundance of these co-dominant taxa along the depth profile and identified the adverse environmental factors driving this decline. The functional traits measured on isolated strains of these two taxa (i.e., size, pigment composition, and concentration) are then compared and discussed to explain their capacity to cope with the extreme environmental conditions encountered in the aphotic, anoxic, and sulfidic layers of the water column of Lake Dziani Dzaha
“I don’t complain, but I am ready for any eventuality”
No full textInternational audiencePurposeThe purpose of this paper is to investigate the extent to which the influence of professional commitment on intention to leave a profession is contingent on the combined effect of job search and sportsmanship.Design/methodology/approachThe research is based on a sample of professional employees (N = 327). Moderated moderation was the approach used for testing the hypotheses.FindingsFindings showed that the moderating effect of job search on the relationship between professional commitment and intention to leave a profession is higher at a low level of sportsmanship and lower when sportsmanship is high.Originality/valueThe research indicates that job search does not necessarily constitute a sign of acceleration of intention to leave one’s profession. In the case of professionals expressing a high level of sportsmanship, job search appears more like a precaution
An Institutional Perspective on the Adoption of Open Dashboard for Health Information Systems in Tanzania
No full textPart 2: Digital Platforms for DevelopmentInternational audienceThis article attempts to understand the adoption and institutionalisation of open dashboards in the health information system in Tanzania as part of the national initiative in strengthening the routine health information systems through data-driven approaches. Using an institutional perspective, specifically the concept of institutional work, the article analyses the efforts of a group of actors aimed at disrupting existing structures, thereby creating new ones and diffusing them within and across organisations. We argue that for the institutionalisation of open dashboards in health information systems, serendipity moments are necessary and should be coupled with actors willing to mobilising others within the network. Furthermore, we argue that the use of participatory approach has the potential to align interests from diverse stakeholders hence providing a mechanism for transforming rooted organisational routines
Emigration des profils qualifiés et ses effets sur le développement du Cameroun The effetcts of « brain drain » on develppment in Cameroon
No full textInternational audienceCet article a pour objectif d'analyser les « brain drain effect » dans un contexte spécifique qui est celui du Cameroun. Territoire au paysage de développement parfois répulsif, le Cameroun souffre ainsi d'une « crise de développement » généralisée. Cette situation favorise une économie au large réservoir de chômeurs très qualifiés et/ou peu qualifiés. Depuis les années 1990, aucune évolution majeure n'est observée dans la dynamique de développement du Cameroun. En plus, son indice de développement humain le range dans la catégorie des pays moyens ou moins avancés.Le Cameroun fait ainsi, partie des pays qui peine à absorber son capital humain formé sur place. Dans cette perspective, pour fuir le déterminisme contextuel, les cadres qualifiés migrent vers des zones plus attractives et/ou moins répulsives. En 1990, le Cameroun avait plus de 1434 des 9515 immigrants nantis d'une formation universitaire résidant aux Etats-Unis. En 2000, le taux d'émigration des diplômés de l'enseignement supérieur était estimé à 17,2%. Ce phénomène prive le pays des ressources humaines susceptibles de favoriser son développement. Le secteur de la santé semble le plus touché. D'après l'Ordre des médecins, 4200 médecins camerounais, en majorité des spécialistes, exercent à l'étranger. Au Cameroun, il en reste seulement 800, ce qui fait un médecin pour 10.000 à 20.000 habitants dans les villes et un médecin pour 40.000 à 50.000 dans les zones périphériques. Ceci entraine le déclin progressif du pays. Cependant, une lecture transnationalisteet interprétative de ce phénomène permet d'observer que cette migration de personnels qualifiés constitue en même temps une fuite de cerveaux, une stratégie de gestion d'excédents en ressources humaines et un potentiel facteur de développement à long terme. Abstract This article aims to analyze "brain drain"effectsin the specific context of Cameroon. As
Handover Management in Femtocell LTE Networks Under Fast Varying Channels
No full textPart 4: Local Technical PapersInternational audienceTo increase network capacity of a mobile communication system, three main ways can be derived from Claude Shannon equation. These are the use of smaller cells, increase of bandwidth and improvement of communication technology. Since there is only a finite amount of radio spectrum available and it is also required by other applications, there are limits to bandwidth increment. Combining the later and former, LTE small cells method is best practical way to increase system capacity of mobile communication system. However, deployment of femtocells with small coverage range leads to frequent handover initiation. The problem escalates when femtocells operate in open access mode while accommodating highly mobile users who initiate unnecessary handovers as they stay in a femtocell for short time. To tackle these challenges, a hybrid handover decision algorithm is presented. The proposed algorithm selects the most appropriate target femtocell for handover using velocity of the user, throughput gain and adaptation of signal averaging and hysteresis margin methods. Simulation results show 1.7 times reduction in the amount of handovers in comparison with the traditional handover schemes
The Role of Human Centered Design (HCD) and Challenge Driven Education in Enhancing the Innovation Capacity of Africa’s Young People: Case of Youth for Children (Y4C) Innovation Hub in Tanzania
No full textPart 4: Sustainable ICT, Informatics, Education and Learning in a Turbulent World - “Doing the Safari Way”International audienceAs the world advances rapidly and economic conditions continue to change, issues such as globalization and changing labour markets are putting a huge pressure on youth worldwide. There is an urgent need for young people to be trained with flexible set of skills that will allow them to take the front seat and actively contribute to initiatives directly affect their development. The first step towards addressing the pressing concerns of today’s youth, especially in Africa, involves improving the existing education systems. This paper elaborates curriculum improvement in education systems by adapt a human centered design (HCD) and Challenge-Driven Education (CDE) approaches that encourages students to work on projects that address real challenges solicited from industry partners. Youth for Children (Y4C) innovation hub, a partnership between UDSM college of ICT (CoICT) and UNICEF Tanzania, was established in 2016 to promote child rights and provide the design skills and social context to support students in developing products and solutions with real social value. Y4C Hub provides unique value in its emphasis on HCD and CDE approaches where projects are undertaken for a period of one year and are directly linked to solving real challenges facing the society in collaboration with the challenge owners and mentors. In the year since launching the hub, 173 CoICT students, 36 supervisors, and 50 secondary school girls have been trained on HCD. A Final Year Project course curriculum has been reviewed to reflect a more challenge driven approach, offering a chance for promising projects to be incubated