52 research outputs found
Advancing public health: enabling culture-fair and education-independent automated cognitive assessment in low- and middle-income countries
No full textCITATION Garuma D, Lamba D, Abessa TG and Bonnechère B () Advancing public health: enabling culture-fair and education-independent automated cognitive assessment in low-and middle-income countries.The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This study was supported by the NASCERE program
Edible fungi consumed by the Lamba and Bemba people of Haut-Katanga (DR Congo)
No full textThe objective of this work is to establish a list of species of edible fungi consumed by the Lamba and Bemba people of Haut-Katanga (DR Congo). This study contributes to the valorization of edible fungi gathered in the miombo woodlands of Haut-Katanga. A survey was conducted among Lamba and Bemba people of the peri-urban area of Lubumbashi. The first author conducted structured and semi-structured surveys among 331 people, mostly women aged 30-50.
The results show the existence of thirty-eight edible species belonging to 9 genera and 8 families. The majority is ectomycorrhizal (66%) followed by Termitomyces (21%), while only a few are saprotrophic (13%). Lamba and Bemba people consume all taxa. Twenty-three local names have been recorded in their respective languages, i.e., Kilamba and Kibemba, two closely related Bantu languages belonging to the family’s Eastern clade. The Lamba and Bemba do not consume species of the genera Russula (Russulaceae) and Boletus (Boletaceae). We succeeded in reconstructing the conceptualization underlying the creation of several Kibemba and Kilamba mushroom names. Popular and scientific taxonomies rarely overlap: one and the same species may have different names in Kilamba and Kibemba, while one and the same name in Kilamba and/or Kibemba is often used for several congeneric species. Species considered toxic and not consumed do not have a Kilamba or Kibemba name of their own. Instead, they are collectively referred to by a term fyana fya bene, literally meaning “big (dangerous) children of them” and signaling that local consumers reject those species
Variable-range hopping: role of Coulomb interactions
No full textThe effect of Coulomb interactions on hopping conduction in the variable-range hopping regime is analyzed within a linear-response formalism. Here the conductivity and the dielectric function are related to the density-density response function for which a generalized master equation (GME) can be derived using the Mori-Zwanzig projector formalism. The GME can be thought of as a random resistor network with frequency-dependent internode conductances, whose values can be determined from a function related to the current-current correlator at the two nodes. We evaluate the internode conductances using a diagrammatic perturbation formalism. For a single electron hop with all the other charges frozen, we obtain hop rates correct to all orders in Coulomb interaction. This gives us a finite temperature generalization of existing results for the interacting system. We then incorporate relaxation effects that accompany electron hops, using a dynamical model of the Coulomb gap. We argue that the parameter that governs the local relaxation is related to the conductivity itself. These internode conductances are then used to calculate the dc conductivity of the network by effective- medium approximation. We show that a crossover from Efros-Shklovskii's T½ behavior to Mott's T¼ behavior occurs due to the relaxation effects, as the temperature is increased. At low temperatures the relaxation is slow so that electrons hop in a frozen charge background and thereby sense the Coulomb gap. This gives the T½ behavior. At higher temperatures the relaxation gets faster and the Coulomb gap is alleviated leading to Mott's behavior
Vaya que lo lamba un sapo
No full textVaya que lo lamba un sapo se encuentra conformado por seis cuentos independientes, que pueden conectarse por medio de la aparición de personajes recurrentes. Dichos relatos no comparten temáticas realmente claras: cada historia pretende ser distinta, pues, son vivencias especiales, y probablemente únicas, que dotan de un sentido singular a cada personaje. Sin embargo, la colección de cuentos se entrelaza bajo una propuesta estética que, a pesar de ser claramente realista, tiende a guiarse por valores grotescos, absurdos y cómicos hasta el punto de rayar en lo fantástico. Asimismo, pretende ejemplificar una corriente lingüística clara que dota de color y tono los distintos niveles en donde se desarrollan las narrativas. Tales tendencias, por las que la autora se inclina, se ven permeadas por un estilo laxo e inteligible que permite un acercamiento sencillo a los distintos relatos y una comprensión clara de lo expuesto. No obstante, esa fácil accesibilidad no le arrebata a los cuentos su capacidad de alterar y conmover al lectorVaya que lo lamba un sapo is made of up six independent stories, that can be connected by recurrent characters. These stories don't share clear themes: each tale pretend to be different, because they are special and unique experiences that give to each character a remarkable meaning. Nevertheless, the tales collection intertwines under an aesthetic proposal that, despite being clearly realistic, tends to be guided by grotesque, absurd and comic values bordering on the fantastic. Likewise, it aims to exemplify a clear linguistic current that gives color and tone to the different levels where the narratives unfold. Such tendencies, towards which the author leans, are permeated by a loose and intelligible style that allows a simple approach to the different stories and a clear understanding of what is exposed. However, this easy accessibility does not rob stories of their ability to alter and move the readerLiteratoPregrad
Single domain magnetic arrays: role of disorder and interactions
No full textThe hysteresis of an array of interacting single domain magnetic particles is studied, where the particles interact via exchange and dipolar interactions. The dependence of the magnetic properties on the distribution of grain sizes, the density of the grains, the anisotropy energy and the exchange interactions in the array is investigated through Monte Carlo simulations for
nanoparticle systems. We also present some experimental results on the
-polypyrrole nanocomposite system which agree with the trends observed in our simulations
Dielectric properties of the electron glass
No full textThe dielectric-constant matrix of a system of electrons that have been localized by disorder is calculated as a function of frequency and distance. It is shown that the basic polarization process in these systems is quite different from those with extended electrons, as the electronic transitions can only occur by phonon-mediated hops between localized states. It is also argued that the random-phase approximation is not adequate for such systems, as the correct account for the excitation energies of the system requires inclusion of electron-hole interaction. Our analysis provides an expression for screening length that shows a basic departure from the Thomas-Fermi approximation. On the basis of our results for polarizability, we also argue that a soft Coulomb gap for electron-hole excitations should exist to provide dielectric stability to the system
Temperature dependent photoluminescence in self assembled InAs quantum dot arrays
No full textIn this paper we investigate the competing effects of thermally assisted hopping and radiative recombination of disorder induced spatially localized excitons on the temperature dependent PL spectrum of a self assembled InAs quantum dot array on GaAs. The stationary photoluminescence spectrum due to the lowest exciton state is calculated from a Monte Carlo simulation. We have also included the effect of the narrowing of the band gap with the increase of temperature. Our results on variation of the peak position and linewidth of the PL spectrum with temperature are in agreement with existing experimental results on InAs/GaAs dot arrays
Role of defects in transport through a quantum dot single electron transistor
No full textThe effect of a single dotlike defect on the transport through a quantum dot single electron transistor weakly coupled to external leads is studied. It is found that the conductance profile is changed significantly by the quantum mechanical tunneling between the dot and the defect and the interactions between them, both of which are dependent on the distance between the dot and the defect, as also by the morphology of the defect. In particular, we find that even a very small strength of interdot interaction has a major influence on the transport and must be taken into account in device fabrication
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