Vision-driven Autocharacterization of Perovskite Semiconductors

In materials research, the task of characterizing hundreds of different materials traditionally requires equally many human hours spent measuring samples one by one. We demonstrate that with the integration of computer vision into this material research workflow, many of these tasks can be automated, significantly accelerating the throughput of the workflow for scientists. We present a framework that uses vision to address specific pain points in the characterization of perovskite semiconductors, a group of materials with the potential to form new types of solar cells. With this approach, we automate the measurement and computation of chemical and optoelectronic properties of perovskites. Our framework proposes the following four key contributions: (i) a computer vision tool for scalable segmentation to arbitrarily many material samples, (ii) a tool to extract the chemical composition of all material samples, (iii) an algorithm capable of automatically computing band gap across arbitrarily many unique samples using vision-segmented hyperspectral reflectance data, and (iv) automating the stability measurement of multi-hour perovskite degradation experiments with vision for spatially non-uniform samples. We demonstrate the key contributions of the proposed framework on eighty samples of unique composition from the formamidinium-methylammonium lead tri-iodide perovskite system and validate the accuracy of each method using human evaluation and X-ray diffraction.Comment: Manuscript 8 pages; Supplemental 7 page

Effet de la fréquence de récolte et des milieux de dilution sur la qualité du sperme de taureau de race Borgou

La présente étude a pour but d’évaluer la production et la qualité de sperme de 17 taureaux Borgou. L’expérimentation a été réalisée sur la base des séances de récolte tous les 4 jours, pendant 36 jours au cours desquels l’efficacité in vitro de six milieux de dilution sur la motilité et la vitalité des spermatozoïdes (spz) a été testée pendant 28 jours. Les résultats ont montré que la fréquence de récolte expérimentée n’affecte pas la qualité des éjaculats qu’on pourrait utiliser pour l’insémination artificielle à l’état frais (+5 °C). L’effet des différents dilueurs sur la motilité et la viabilité des spermatozoïdes, a prouvé que ces spermatozoïdes supportaient moins bien le milieu à base de lait de coco que ceux à base de jaune d’oeuf et de lait de vache. Cependant, tous les milieux de dilution testés peuvent être utilisés pour conserver les semences +5 °C durant 48 heures. La durée de conservation peut être étendue à 72 heures pour le lait de vache et le jaune d’oeuf.Mots clés: Sperme, insémination artificielle, dilueurs, éjaculats, bovin, Beni

A fast ILP-based Heuristic for the robust design of Body Wireless Sensor Networks

We consider the problem of optimally designing a body wireless sensor network, while taking into account the uncertainty of data generation of biosensors. Since the related min-max robustness Integer Linear Programming (ILP) problem can be difficult to solve even for state-of-the-art commercial optimization solvers, we propose an original heuristic for its solution. The heuristic combines deterministic and probabilistic variable fixing strategies, guided by the information coming from strengthened linear relaxations of the ILP robust model, and includes a very large neighborhood search for reparation and improvement of generated solutions, formulated as an ILP problem solved exactly. Computational tests on realistic instances show that our heuristic finds solutions of much higher quality than a state-of-the-art solver and than an effective benchmark heuristic.Comment: This is the authors' final version of the paper published in G. Squillero and K. Sim (Eds.): EvoApplications 2017, Part I, LNCS 10199, pp. 1-17, 2017. DOI: 10.1007/978-3-319-55849-3\_16. The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-55849-3_1

Algorithm Engineering in Robust Optimization

Robust optimization is a young and emerging field of research having received a considerable increase of interest over the last decade. In this paper, we argue that the the algorithm engineering methodology fits very well to the field of robust optimization and yields a rewarding new perspective on both the current state of research and open research directions. To this end we go through the algorithm engineering cycle of design and analysis of concepts, development and implementation of algorithms, and theoretical and experimental evaluation. We show that many ideas of algorithm engineering have already been applied in publications on robust optimization. Most work on robust optimization is devoted to analysis of the concepts and the development of algorithms, some papers deal with the evaluation of a particular concept in case studies, and work on comparison of concepts just starts. What is still a drawback in many papers on robustness is the missing link to include the results of the experiments again in the design

The challenge of habitat modelling for threatened low density species using heterogeneous data : the case of Cuvier’s beaked whales in the Mediterranean

We are grateful to the ACCOBAMS Secretariat for their support in this work, including a small grant for the analysis.The Mediterranean population of Cuvieŕs beaked whale (Ziphius cavirostris), a deep-diving cetacean, is genetically distinct from the Atlantic, and subject to a number of conservation threats, in particular underwater noise. It is also cryptic at the surface and relatively rare, so obtain robust knowledge on distribution and abundance presents unique challenges. Here we use multiplatform and multiyear survey data to analyse the distribution and abundance of this species across the Mediterranean Sea. We use a novel approach combining heterogeneous data gathered with different methods to obtain a single density index for the region. A total of 594,996 km of survey effort and 507 sightings of Cuvier’s beaked whales, from 1990 to 2016, were pooled together from 24 different sources. Data were divided into twelve major groups according to platform height, speed and sea state. Both availability bias and effective strip width were calculated from the sightings with available perpendicular distance data. This was extrapolated to the rest of the sightings for each of the twelve groups. Habitat preference models were fitted into a GAM framework using counts of groups as a response variable with the effective searched area as an offset. Depth, coefficient of variation of depth, longitude and marine regions (as defined by the International Hydrographic Organization) were identified as important predictors. Predicted abundance of groups per grid cell were multiplied by mean group size to obtain a prediction of the abundance of animals. A total abundance of 5799 (CV = 24.0%) animals was estimated for the whole Mediterranean basin. The Alborán Sea, Ligurian Sea, Hellenic Trench, southern Adriatic Sea and eastern Ionian Sea were identified as being the main hot spots in the region. It is important to urge that the relevant stakeholders incorporate this information in the planning and execution of high risk activities in these high-risk areas.PostprintPeer reviewe

Genomic and phenotypic insights from an atlas of genetic effects on DNA methylation

DNA methylation quantitative trait locus (mQTL) analyses on 32,851 participants identify genetic variants associated with DNA methylation at 420,509 sites in blood, resulting in a database of >270,000 independent mQTLs.Characterizing genetic influences on DNA methylation (DNAm) provides an opportunity to understand mechanisms underpinning gene regulation and disease. In the present study, we describe results of DNAm quantitative trait locus (mQTL) analyses on 32,851 participants, identifying genetic variants associated with DNAm at 420,509 DNAm sites in blood. We present a database of >270,000 independent mQTLs, of which 8.5% comprise long-range (trans) associations. Identified mQTL associations explain 15-17% of the additive genetic variance of DNAm. We show that the genetic architecture of DNAm levels is highly polygenic. Using shared genetic control between distal DNAm sites, we constructed networks, identifying 405 discrete genomic communities enriched for genomic annotations and complex traits. Shared genetic variants are associated with both DNAm levels and complex diseases, but only in a minority of cases do these associations reflect causal relationships from DNAm to trait or vice versa, indicating a more complex genotype-phenotype map than previously anticipated.Molecular Epidemiolog

Stabilité de l’huile de coton d’origine béninoise au cours du stockage.

Huile équilibrée et aux vertus diététiques incontestables, l’huile de coton, à l’instar des huiles végétales insaturées, peut subir au cours du stockage des réactions d’oxydation ou d’hydrolyse qui affectent sa stabilité et ses caractéristiques organoleptiques.Dans le but de déterminer les conditions permettant un meilleur stockage, l’influence de la nature de l’emballage, de la lumière et de la température de stockage sur la stabilité de cette huile a été étudiée. De cette étude, il ressort que les bidons opaques et les emballages en polyéthylène de terephtalate (PET) conservent l’huile de coton de la même manière. La lumière et l’élévation de la température accélèrent l’oxydation de l’huile qui perd ses qualités initiales. En effet, l’indice de peroxyde passe respectivement de 5,6 meq d’O2/Kg à 27,71 pour l’échantillon stocké dans le PET et à 27,36 pour celui stocké dans les bidons opaques, soit une augmentation presque similaire dans les deux types d’emballage. L’obscurité permet une meilleure stabilité oxydative de l’huile de coton. En effet, pendant que l’huile stockée à la lumière atténuée présente son premier pic le 14ème jour, correspondant à un indice de peroxyde de 25,22 meq d’O2/Kg, l’huile stockée à l’obscurité n’atteint le sien que le 56ème jour avec un indice de 21,47 meq d’O2/Kg.L’huile de coton stockée à 10 °C présente un indice de peroxyde presque deux fois inférieure à celle stockée à 20 °C.Les bidons opaques et les emballages en PET utilisés, limitent la réhydratation de l’huile de coton conservée et donc son hydrolyse chimique, favorisant ainsi sa stabilité lors du stockage.Mots clés : Huile de coton, stabilité, conditions de stockage, oxydation.Oil with the undeniable dietetic virtues, the cotton seed oil, like other unsaturated vegetable oils, is subjected during the storage, to the reactions of oxidation which affect its organoleptic characteristics and stability.In this paper, the influence of the nature of packing, light and temperature of storage on the stability of this oil was studied to determine the conditions allowing a better storage.The results obtained show that the opaque cans and the terephtalate polyethylene packing (PET) preserve the cotton seed oil in the same way. The light and the rise in the temperature accelerate the oxidation of the oil which loses its initial qualities. Indeed, the peroxide index passes respectively from 5.6 meq of O2 / Kg to 27.71 for the sample stored in the PET and to 27.36 for that stored in the opaque cans, that is to say a similar increase in the two types of packing.The darkness allows a better oxidative stability of the cotton seed oil. Indeed, while the oil stored with the attenuated light presents its first peak the 14th day, corresponding to a peroxide index of 25.22 meq of O2/ Kg, the oil stored with the darkness reaches to it only the 56th day with an index of 21.47 meq of O2 /Kg.The cotton seed oil stored to 10 °C presents a peroxide index almost twice lower than that stored at 20 °C. The cans and packing in PET used, limit the rehydration of the cotton seed oil preserved and thus its chemical hydrolysis, thus supporting its stability during storage.Key words: Cotton seed oil, stability, storage conditions, oxidation