Optimal design of nanomagnets for on-chip field gradients

The generation of localized magnetic field gradients by on-chip nanomagnets is important for a variety of technological applications, in particular for spin qubits. To advance beyond the empirical design of these nanomagnets, we propose a systematic and general approach based on the micromagnetic formulation of an optimal field gradient source. We study the different field configurations that can be realized and find out quantitatively the most suitable ferromagnetic layer geometries. Using micromagnetic simulations, we then investigate the minimum requirements for reaching magnetic saturation in these nanomagnets. In terms of either longitudinal or transverse field gradient, the results provide an optimal solution for uniform, saturated nanomagnets, where the magnetic material can be selected according to the strength of the external fields that can be used.Comment: 10 pages, 4 figures, supplemental material. All comments most welcom

Remaking the self in John Dunton’s The Life and Errors of John Dunton (1705)

© 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group. John Dunton (1659–1732) is a bookseller and writer best known today as a tireless self-promoter whose I-centred and experimental work contributed to the development of the novel and autobiography in the eighteenth century. This article is the first full-length study of his own autobiographical record, The Life and Errors of John Dunton (1705). Dunton the showman is in plentiful evidence in this text, but he also presents another, more sober and serious-minded version of the self by following accounts of earlier stages of his life with their reformed versions. His coupling of religious-led self-examination with a commitment to literary novelty makes The Life a most unusual form of spiritual autobiography in its early stages. Yet The Life is a composite text in an even more obvious sense than this. For around half-way through the text Dunton abandons his close focus on the self for hundreds of cursory character sketches of his contemporaries, and in doing so swaps spiritual considerations for indirect comments on his own social activities and commercial concerns. This article studies these two main, ostensibly opposed, sections of The Life–its autobiographical and biographical material–and suggests points of contact between them

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Mitochondrial physiology

As the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery

Genetic Diversity and Environmental Adaptation in Tropical Forest Trees : Study of Virola Genus (Myristicaceae)

Le maintien de ressources génétiques suffisamment larges est nécessaire pour assurer la viabilité et le potentiel évolutif des populations naturelles. Cette thèse a le principal objectif de caractériser la diversité et la variabilité génétique chez le genre Virola (Myristicaceae) pour décrire les processus évolutifs qui en sont à l'origine. Premièrement,une étude de la régénération d'un échantillonnage exhaustif de V. michelii a été menée dans une parcelle du dispositif expérimental de Paracou ayant subi une exploitation forestière de faible intensité et comparée à une parcelle témoin. La diversité génétique mesurée à partir de marqueurs AFLP (Amplified Fragment-Length Polymorphism, N=229) en zones perturbées s'est révélée être plis grande qu'en zone non-perturbées. Puis, l'adaptation locale a été étudiée à travers ces mêmes individus et certains loci (AFLP) montrent une sélection divergente pour des environnements contrastés, indiquant un signe d'adaptation. Enfin, l'étude des niveaux de divergence génétique chez trois espèces de Virola du bouclier guyanais (V. michelii, V. surinamensis et V. kwatae) montrent que deux d'entre elles (V. surinamensis et V. kwatae) montrent de fortes similarités génétiques malgré leur distribution sur des environnements contrastés. des Flux de gènes intersécifiques ont été mis en évidence chez ces deux espèces-soeurs et l'hypothèse d'une spéciation écologique est avancée. Ce travail a permis d'aborder différents processus évolutifs à l'origine de la diversité génétique actuelle chez ces espèces forestières tropicales et peut fournir une contribution pour appréhender le devenir des populations.Genetic diversity is an essential component of biodiversity. The maintenance of sufficient genetic resources is needed to ensure the adaptive potential and the viability of natural populations. In the current context of global changes, the study of adaptation in living organisms is a key task, particularly for tropical forest trees that are dominant components (in terms of biomass and as ecological drivers) of some of the most diverse ecosystems on Earth. The main objective of this thesis is to characterize genetic diversity and genetic variability to understand the evolutionary processes that act on them. This ecological-genetic study was carried out at the interspecific and intraspecific level in the Virola genus.If overall high levels of genetic diversity are a guarantee of prosperity for the future of the species, it seems essential to perform studies on the impact of environmental disturbance on genetic diversity. In the first section, the genetic consequences of regeneration dynamics were studied in an exhaustive sample of V. michelii in a low-intensity logging plot and in a control plot at the Paracou experimental site. A greater genetic diversity, measured from AFLP markers (Amplified Fragment Length Polymorphism, N = 229), was found in perturbed areas. Because studying genetic diversity within species may be useful for understanding species adaptation to environmental changes, in the second section. I studied local adaptation in a population of V. michelii on the Paracou experimental site. A genome scan approach with AFLPs (N = 229) was conducted on 77 adult individuals and 401 juveniles to identify genetic differences between populations associated to contrasting conditions for an array of environmental variables. Some loci (N = 2) were found to be subject to divergent selection, indicating adaptation to contrasting habitats.In the third section, the study of levels of genetic divergence in three Virola species of the Guiana Shield (V. michelii, V. surinamensis and V. kwatae) was investigated for nuclear and chloroplast molecular markers. V. surinamensis and V. kwatae showed strong genetic similarities despite their contrasting habitats preferences. Coalescent analyses have revealed, on one hand, a recent divergence between these two species suggesting an ecological speciation, and one the other hand that interspecific gene flow occurs between these sister-species.This work focuses on understanding evolutionary processes shaping genetic diversity and provides a useful contribution for biodiversity conservation programs

Place de l' ECG dans la prédiction du risque cardiovasculaire et rénal chez le patient diabétique de type 2

Contexte : Les complications cardiovasculaires et rénales font la gravité au long cours du diabète de type 2. Les sociétés savantes recommandent l utilisation de scores permettant de stratifier le risque de survenue de telles complications, mais la littérature manque d un score simple et fiable d utilisation. L ECG pourrait avoir une valeur prédictive additionnelle dans l estimation du risque. Méthode : 1241 patients ont bénéficié d un suivi prospectif entre 2001 et 2012 au sein de l étude SURDIAGENE (Poitiers). Les critères de jugement étaient un critère composite CSD des complications sévères du diabète (décès cardiovasculaire, infarctus du myocarde, AVC, hospitalisation pour insuffisance cardiaque, insuffisance rénale terminale) et la survenue de complications cardiovasculaires CV (décès cardiovasculaire, coronaropathie, insuffisance cardiaque, artériopathie des membres inférieurs). Deux modèles de cox multivarié incluant les données ECG obtenues lors de la première consultation ont permis de construire deux scores prédictifs des complications CSD et CV liées au diabète de type de 2. Résultats : Avec un suivi médian de 5 ans, 334 patients (27%) ont présenté le critère CSD (densité d incidence de 55 personnes-années) et 398 (32%) ont présenté le critère CV (densité d incidence de 68/1000 personnes-années). En régression multivariée, les paramètres ECG FA, présence d une onde Q, et produit de Cornell>2440mV.ms étaient des paramètres indépendant prédictifs du risque de survenue du critère CSD (risques relatifs respectivement de 1.6 [1,2-2,4], 1.5 [1,2-1,9], et 1.4 [1,09-1,9]) et du critère CV (risques relatifs respectivement de 1.6 [1,1-2,35], 1.3 [1,05-1,6], et 1.4 [1,07-1,8]). Un score simplifié a été construit pour chaque critère, en associant aux données ECG, des données cliniques (Sexe, age, antécédents cardiovasculaires, rétinopathie diabétique, traitement médicamenteux) et biologiques (albuminurie, débit de filtration glomérulaire) afin d estimer facilement au lit du patient diabétique, le risque à 5 ans de survenue de complications CSD ou CV. Conclusion : Ces scores permettraient de stratifier plus aisément au lit du patient le risque à moyen terme de complications chez le diabétique, pouvant conduire le clinicien à modifier son attitude thérapeutique. Des procédures de validation externe sont toutefois nécessaires.LILLE2-BU Santé-Recherche (593502101) / SudocSudocFranceF

Comparison of flooding resistance in salt-marsh (Arctosa fulvolineata and Pardosa proxima) and forest (Pardosa lugubris) spiders (Araneae : Lycosidae).

Poste

Comparison of flooding resistance in salt-marsh (Arctosa fulvolineata and Pardosa proxima) and forest (Pardosa lugubris) spiders (Araneae : Lycosidae).

Poste

RaBoT: a rarefaction-by-bootstrap method to compare genome-wide levels of genetic diversity

No efficient method is available to compare multi-locus estimates of diversity while taking into account inter-locus and inter-population stochastic variance. The advent of genome scan approaches makes the development of such tests absolutely necessary. We developed a method to compare genome-wide diversity estimates while taking into account-and factoring out-variation in census size and making use of inter-locus variance to assess significance of differences in diversity levels. An approach based on rarefaction with bootstrap re-sampling (RaBoT) was implemented into a test of multi-locus comparison of diversity coded in R. The properties of the test were studied by applying it to simulated populations with varying diversity levels and varying differences in diversity levels. The test was then applied to empirical data from disturbed and undisturbed populations of Virola michelii (Myristicaceae) genotyped at 693 amplified fragment length polymorphism (AFLP) markers. RaBoT was found to be rather conservative, with large numbers of false negatives when the diversity in the compared populations was similar, and false positives mostly associated to comparisons of populations with extremely high levels of diversity. When applied to empirical data, RaBoT detected higher genetic diversity in a post-disturbance than in an undisturbed population and lower genetic diversity in a seedling than in the corresponding adult population, but it also revealed differences in diversity between subgroups within the disturbed and undisturbed plots. RaBoT is a sensitive method to compare multi-locus levels of diversity that can be applied both at the genotype level for dominant markers (e.g. AFLP) and at the allele level for biallelic codominant markers (e.g. single-nucleotide polymorphisms)

Life after disturbance (II): the intermediate disturbance hypothesis explains genetic variation in forest gaps dominated by Virola michelii Heckel (Myristicaceae)

International audienceKey message: Genetic diversity appears to be unaffected by disturbance in a stand of the light-demanding Neotropical treeV. michelii. Although spatial genetic structure is modified in post-disturbance cohorts, mixing of seeds from different mother trees in canopy gaps appears to efficiently maintain genetic admixture. Context: The interplay between genetic and demographic processes has major consequences on population viability. Population size affects demographic trends, while genetic diversity insures viability by reducing risks of inbreeding depression and by maintaining adaptive potential. Yet, the consequences of increases in census size (as opposed to effective size) on genetic diversity of forest populations are poorly known. Aims: We have studied the structure of genetic diversity in populations of saplings of the light-responsive tree, Virola michelii (Myristicaceae, the nutmeg family), in two plots having undergone different levels of canopy-gap opening disturbance. This allowed us to test the “intermediate disturbance” hypothesis, which generally applies to species diversity, at the intra-specific scale. Methods: Levels and distribution of genetic diversity were compared between plots and between life stages. Sapling parentage was analysed to infer each adult tree’s contribution to regeneration. Results: Genetic diversity was higher, and spatial genetic structure was stronger in the post-disturbance than in the control seedling population. Parentage analysis suggested that a limited number of parents contributed to most of the regeneration, but that efficient mixing of their progeny may have enhanced the diversity of saplings occupying canopy gaps. Conclusion: A mixture of demo-genetic processes may contribute to maintain genetic diversity in spite of, or possibly due to, ecosystem disturbance in V. michelii