bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution and bioaccumulation of Endocrine Disrupting Chemicals (EDCS) in Lagos Lagoon water, sediment and fish
Authors: Adeyi A.A. 
Published: January 2021

Toxic chemical contaminants released from industrial, agricultural, and municipal sources continues to threaten aquatic ecosystems. Aquatic ecosystems act as the final sinks accumulating and transporting numerous chemicals such as octylphenol (OP), nonylphenol (NP) and bisphenol-A (BPA). These chemicals are undesirable as they have been reported to possess endocrine disrupting properties. This study therefore assessesthe distribution and bioaccumulation of endocrine disrupting chemicals (EDCs) in Lagos Lagoon. Water and sediment samples were collected at nine different locations on the lagoon. Five different species of fishes were also collected, identified and homogenized prior to sample pre-treatment. Samples were extracted, clean-up, derivatized and analysed by gas chromatography–mass spectrometry. Physicochemical properties of the samples were also determined. In the water samples, BPA was not detected in all the samples collected at the different locations while the concentrations of NP and OP ranged from ND-102 ng/L and ND-127 ng/L, respectively. The concentrations of the targeted compounds in the sediment samples ranged from ND- 5.08 μg/g BPA, ND-1.90 μg/g NP, and ND- 2.51 μg/g OP while the concentrations ranged from ND-1139 ng/g BPA, ND-476 ng/g NP, and ND-643 ng/g OP in the fish samples. This study revealed the occurrence of EDCs in Lagos lagoon water and their accumulation in biota therein, which can have detrimental effects on other organisms across the food chain. Thus, the need to monitor these endocrine disrupting chemicals is imperative.
Keywords: EDCs; BPA; OP; NP; Lagos lagoon
Isolation of 2, 5-dithia-3, 6-diazabicyclo [2.2.1] heptane and GC-MS analysis of silylated extract from Tragia benthamii
Authors: Balogun O.S. , Oladosu I.A. , Liu Zhiqiang 
Published: January 2021

Tragia benthamii is a medicinal plant of repute endemic in West Africa. However, despite the traditional uses of the plant its secondary metabolites are yet to be profiled. Thus, this study aimed at identifying the chemical constituents of T. benthamii. Air-dried samples (600 g) of the plant were extracted with aqueous ethanol (95 %) and thereafter, portions of the crude extract obtained were used separately for chromatographic purifications, GC-MS analysis and spectrophotometric quantitation of the secondary metabolites. The chromatographic purification of the extract afforded a pure compound elucidated as 2,5-dithia-3,6-diazabicyclo [2.2.1] heptane using spectroscopic techniques. Upon silylation and GC-MS analysis of the extract, derivatives of sugar (34.65%), fatty acids (24.11%) and phytol (21.00%) were identified as principal constituents. Also, a total of 6.25 mg rutin/g, 5.18 mg ginsenoside/g and 6.84 mg glucose/g dry weight sample were obtained for flavonoids, saponins and carbohydrate, respectively from the spectrophotometric quantitation. These secondary metabolites are being reported for the first time from this plant.
Keywords: Tragia benthamii; secondary metabolites; quantitative analysis; silylation
NGHIÊN CỨU MỘT SỐ YẾU TỐ ẢNH HƯỞNG TỚI VIỆC CHIẾT TÁCH VÀ XÁC ĐỊNH TÍNH KHÁNG KHUẨN, KHÁNG OXY HÓA CỦA DỊCH CHIẾT POLYPHENOL TỪ CÂY CHUA ME ĐẤT HOA VÀNG (OXALIS CORNICULATA L.)
Authors: NGỌC KHÔI PHẠM , THỊ HOÀI NHIÊN NGUYỄN 
Published: January 2021

Đặt vấn đề: Cây chua me đất hoa vàng (Oxalis corniculata L.) được biết đến qua kinh nghiệm dân gian với công dụng chữa ho, viêm họng, sát trùng, mụn nhọt, tay chân lở loét; song hiện vẫn chưa có công trình nào nghiên cứu xác thực giá trị khoa học của loài cây này.
Mục tiêu: Nghiên cứu này được thực hiện nhằm khảo sát sự ảnh hưởng của điều kiện tách chiết đến hàm lượng polyphenol, đánh giá khả năng kháng khuẩn, kháng oxy hóa của dịch chiết polyphenol từ cây chua me đất hoa vàng.
Phương pháp nghiên cứu: Xác định độ tinh khiết của dược liệu, khảo sát sự ảnh hưởng của một số yếu tố đến hàm lượng polyphenol chiết được từ dược liệu, định tính sơ bộ thành phần hóa học của dược liệu và khảo sát hoạt tính kháng khuẩn, kháng oxy hóa của hợp chất polyphenol chiết được từ dược liệu.
Kết quả: Điều kiện chiết thích hợp nhất là: dung môi là methanol, nồng độ 90%, tỷ lệ mẫu:dung môi là 1:10 (g/mL), thời gian 6 giờ, nhiệt độ 60 oC. Khả năng kháng khuẩn ở mức trung bình đến mạnh ở một số chủng vi khuẩn của dịch chiết polyphenol từ cây chua me đất hoa vàng thể hiện qua đường kính vòng vô khuẩn đối với Streptococus feacalis, Proteus mirabili, Staphylococus aureus và Escherichia coli lần lượt là 10,9 mm, 18,2 mm, 21,4 mm và 25,2 mm ở nồng độ dịch chiết là 100 mg/mL. Dịch chiết polyphenol từ cây chua me đất hoa vàng còn thể hiện hoạt tính kháng oxy hóa khá cao với giá trị IC50 của khả năng bắt gốc tự do DPPH là 42,27 mg/mL khi so sánh với giá trị IC50 của vitamin C là 45,81 mg/mL.
Kết luận: Cây chua me đất hoa vàng là một loại dược liệu mới chứa các hợp chất polyphenol có khả năng kháng khuẩn và kháng oxy hóa. Loại dược liệu này có tiềm năng trong công nghệ bào chế dược phẩm và thực phẩm chức năng phục vụ sức khỏe con người.
A New Data Fusion Method for Hybrid MMC/RNA Learning : Application to Automatic Speech Recognition
Authors: Lazli Lilia , Laskri Mohamed Tayeb 
Published: January 2021

It is well known that traditional Hidden Markov Models (HMM) systems lead to a considerable improvement when more training data or more parameters are used. However, using more data with hybrid Hidden Markov Models and Artificial Neural Networks (HMM/ANN) models results in increased training times without improvements in performance. We developed in this work a new method based on automatically separating data into several sets and training several neural networks of Multi-Layer Perceptrons (MLP) type on each set. During the recognition phase, models are combined using several criteria (based on data fusion techniques) to provide the recognized word. We showed in this paper that this method significantly improved the recognition accuracy. This method was applied in an Arabic speech recognition system. This last is based on the one hand, on a fuzzy clustering (application of the fuzzy c-means algorithm) and of another share, on a segmentation at base of the genetic algorithms.
De nombreuses expériences ont déjà montré qu'une forte amélioration du taux de reconnaissance des systèmes MMC (Modèles de Markov Cachés) traditionnels est observée lorsque plus de données d'apprentissage sont utilisées. En revanche, l'augmentation du nombre de données d'apprentissage pour les modèles hybrides MMC/RNA (Modèles de Markov cachés/Réseaux de Neurones Artificiels) s'accompagne d'une forte augmentation du temps nécessaire à l'apprentissage des modèles, mais pas ou peu des performances du système. Pour pallier cette limitation, nous rapportons dans ce papier les résultats obtenus avec une nouvelle méthode d'apprentissage basée sur la fusion de données. Cette méthode a été appliquée dans un système de reconnaissance de la parole arabe. Ce dernier est basé d'une part, sur une segmentation floue (application de l'algorithme c-moyennes floues) et d'une autre part, sur une segmentation à base des algorithmes génétiques.
Shape optimization for the Stokes equations using topological sensitivity analysis
Authors: Maatoug Hassine 
Published: January 2021

In this paper, we consider a shape optimization problem related to the Stokes equations. The proposed approach is based on a topological sensitivity analysis. It consists in an asymptotic expansion of a cost function with respect to the insertion of a small obstacle in the domain. The theoretical part of this work is discussed in both two and three dimensional cases. In the numerical part, we use this approach to optimize the shape of the tubes that connect the inlet to the outlets of the cavity maximizing the outflow rate.
Dans ce papier, on considère un problème d'optimisation de forme lié aux équations de Stokes. On propose une approche basée sur une analyse de sensibilité topologique. On donne un développement asymptotique d'une fonction coût par rapport à la perturbation du domaine par l'insertion d'un petit obstacle. Des résultats théoriques sont donnés en 2 D et 3 D. Dans la partie numérique, on utilise cette approche pour optimiser la forme des tubes liant l'entrée aux sorties d'une cavité
Projections et cohérence de vues dans les grammaires algébriques
Authors: Badouel Eric , Tchoupé Tchendji Maurice 
Published: January 2021

A complex structured document is intentionnally represented as a tree decorated with attributes. The set of legal structures is given by an abstract context-free grammar. We forget about the attributes; they are related with semantical issues that can be treated independently of the purely structural aspects that we address in this article. That intentional representation may be asynchronously manipulated by a set of independent tools each of which operates on a distinct partial view of the whole structure. In order to synchronize these various partial views, we are faced to the problem of their coherence: can we decide whether there exists some global structure corresponding to a given set of partial views and in the affirmative, can we produce such a global structure ? We solve this problem in the case where a view is given by a subset of grammatical symbols, those associated with the so-called visible syntactical categories. The proposed algorithm, that strongly relies on the mechanism of lazy evaluation, produces an answer to this problem even if partial views may correspond to an infinite set of related global structures.
Un document structuré complexe est représenté intentionnellement sous la forme d'une structure arborescente décorée par des attributs. Les structures licites sont caractérisées par une grammaire algébrique abstraite. Nous faisons ici abstraction des attributs ; ces derniers sont liés à des aspects sémantiques qui peuvent être traités séparément des aspects purement structurels qui nous intéressent ici. Cette représentation intentionnelle peut être manipulée de façon indépendante et éventuellement non synchronisée par divers outils d'édition et de manipulation qui opèrent sur des vues partielles distinctes du même document. Pour la re-synchronisation de ces vues partielles nous devons résoudre le problème de leur cohérence : décider s'il existe un document correspondant à ces différentes vues et dans l'affirmative produire un tel document. Nous montrons comment résoudre ce problème dans le cas où chaque vue est associée à un sous-ensemble des symboles grammaticaux : ceux qui correspondent aux catégories syntaxiques visibles. L'algorithme proposé, qui repose fortement sur le mécanisme d'évaluation paresseuse, résout ce problème même dans le cas où chaque vue partielle correspond à un nombre infini de documents possibles.
Quantitative analysis of metabolic networks and design of minimal bioreaction models
Authors: Bastin Georges 
Published: January 2021

This tutorial paper is concerned with the design of macroscopic bioreaction models on the basis a quantitative analysis of the underlying cell metabolism. The paper starts with a review of two fundamental algebraic techniques for the quantitative analysis of metabolic networks : (i) the decomposition of complex metabolic networks into elementary pathways (or elementary modes), (ii) the metabolic flux analysis which aims at computing the entire intracellular flux distribution from a limited number of flux meaurements. Then it is discussed how these two fundamental techniques can be exploited to design minimal bioreaction models by using a systematic model reduction approach that automatically produces a family of equivalent minimal models which are fully compatible with the underlying metabolism and consistent with the available experimental data. The theory is illustrated with an experimental case-study on CHO cells.
Cet article tutoriel traite de la conception de modèles de bioréactions macroscopiques sur la base d’une analyse quantitative du métabolisme cellulaire sous-jacent. L’article commence par un rappel de deux techniques algébriques fondamentales pour l’analyse quantitative des réseaux métaboliques : (i) la décomposition des réseaux métaboliques complexes en chemins élémentaires (ou modes élémentaires), (ii) l’analyse des flux métaboliques qui vise à calculer la totalité des flux métaboliques intracellulaires à partir d’un ensemble limité de mesures. On montre ensuite comment ces deux techniques peuvent être exploitées pour concevoir des modèles minimaux de bioréactions en utilisant une approche systématique de réduction de modèle qui produit automatiquement une famille de modèles minimaux équivalents compatibles non seulement avec les données expérimentales mais aussi avec le métabolisme sous-jacent. La théorie est illustrée avec une étude de cas expérimentale sur des cellules CHO.
Uncoupling Isaacs’equations in nonzero-sum two-player differential games : The example of conflict over parental care
Authors: Hamelin Frédéric , Bernhard Pierre 
Published: January 2021

We use a recently uncovered decoupling of Isaacs PDE’s of some mixed closed loop Nash equilibria to give a rather complete analysis of the classical problem of conflict over parental care in behavioural ecology, for a more general set up than had been considered heretofore.
On utilise un découplage récemment mis en évidence des équations d’Isaacs d’un jeu différentiel pour des stratégies mixtes singulières particulières pour donner une analyse assez complète d’un problème classique en écologie comportementale concernant le conflit à propos des soins parentaux.
Evaluation objective des méthodes de segmentation des maillages polygonaux 3D basée sur la classification de régions
Authors: Zguira Amira , Doggaz Narjes , Zagoubra Ezzeddine 
Published: January 2021

In this paper, we propose an objective evaluation approach of polygonal 3D mesh segmentation algorithms. Our approach is based on region classification. For that, we classify first manual segmented mesh into convex, concave and planar regions. Secondly, we present three quality measures that quantify the similarity of each type of region of the ground-truth relatively to the segmentation obtained by an automatic algorithm. We apply this approach on eight wellselected existing algorithms on heterogeneous images. This provides better understanding as to the strengths and weaknesses of each technique in function of each mesh-regions type in the aim to make the better choice concerning the segmentation algorithms for different applications.
Dans ce papier, nous proposons une approche d'évaluation objective des algorithmes de segmentation des maillages polygonaux 3D, basée sur la classification de régions. Cette approche commence par un processus de classification de régions du maillage constituant la vérité-terrain en régions convexes, concaves et planes. Nous présentons ensuite trois mesures de qualité qui permettent de quantifier la similarité de chaque type de région de la vérité-terrain par rapport à la segmentation obtenue par un algorithme automatique. Nous appliquons l’approche proposée sur un échantillon de huit techniques de segmentation bien choisies sur une base d’images hétérogène. Les résultats d’évaluation obtenus permettent d’assurer une meilleure compréhension des points forts et faibles de chaque technique dans la segmentation des différents types de régions du maillage et ceci afin d’aiguiller correctement le choix des algorithmes de segmentation pour différentes applications.
Population dynamics modelling : Impact of climate change on tick populations
Authors: Khouaja Leila , Ben Miled Slimane , Hbid Hassan 
Published: January 2021

Epidemiology had an important development these last years allowing the resolution of a large number of problems and had good prediction on disease evolution. However, the transmission of several vector-borne diseases is closely connected to environmental protagonists, specially in the parasite-host interaction. Moreover, understanding the disease transmission is related to studying the ecology of all protagonists. These two levels of complexity(epidemiology and ecology) cannot be separated and have to be studied as a whole in a systematic way. Our goal is to understand the interaction of climate change on the evolution of a disease when the vector has ecological niche that depends on physiological state of development. We are particularly interested in tick vector diseases which are serious health problem affecting humans as well as domestic animals in many parts of the world. These infections are transmitted through a bite of an infected tick, and it appears that most of these infections are widely present in some wildlife species.
L'épidémiologie a connu un développement important ces dernières années. Cette discipline a permis une meilleure compréhension del'évolution de maladies. Cependant, plusieurs maladies à transmission vectorielle sont étroitement liées aux protagonistes environnementaux. Ce constat est particulièrement vrai dans le contexte des interactions du parasite avec son hôte. De plus, comprendre la transmission de maladie est lié à l'étude de l'écologie de tous les protagonistes. Notre objectif est de comprendre l'influence du changement climatique sur l'évolution des maladies lorsque la niche écologique du vecteur dépend de l'état de développement physiologique de son hôte. Nous sommes particulièrement intéressés par les maladies vectorielles à tiques qui constituent un grave problème de santé touchant l'être humain et les animaux domestiques dans de nombreuses régions du monde. Ces infections sont généralement transmises par la piqûre d'une tique infectée et il apparaît que la plupart de ces infections sont largement présentées dans certaines espèces fauniques
XPath bipolar queries and evaluation
Authors: Tchoupé Tchendji Maurice , Nguefack Brice 
Published: January 2021

The concept of bipolar queries (also call preferences queries) emerged in the Relational Databasescommunity, allowing users to get much more relevant responses to their requests, expressed via queries say withpreferences. Such requests usually have two parts: the first is used to express the strict constraints and thesecond, preferences or wishes. Any response to a query with preferences must necessarily satisfy the first partand preferably the latter. However, if there is at least a satisfactory answer of the second part, those satisfyingonly the first part will be excluded from the final result: they are dominated. In this paper, we explore an approachof importation of this concept in a XML Database via XPath language. To do this, we propose PrefSXPathlanguage, an extension of XPath in order to express XPath queries with structural preferences, then we presenta query evaluation algorithm of PrefSXPath using automata
Le concept de requêtes bipolaires (on parle aussi de requêtes avec préférences) a émergé dans la communauté des Bases de Données Relationnelles, pour permettre aux utilisateurs d'obtenir des réponses beaucoup plus pertinentes à leurs préoccupations, exprimées via des requêtes dites avec préférences. De telles requêtes ont généralement deux parties : la première permet d'exprimer les contraintes strictes et la seconde, des préférences ou souhaits. Toute réponse à une requête avec préférences doit nécessairement satisfaire la première partie et préférentiellement la seconde. Toutefois, s'il existe au moins une réponse satisfaisant la seconde partie, toutes les réponses ne satisfaisant que la première partie seront exclues du résultat final : elles sont dominées. Dans ce papier, nous explorons une approche d'importation de ce concept dans les Bases de Données XML via le langage XPath. Pour ce faire, nous proposons le langage PrefSXPath, une extension du langage XPath permettant d'exprimer les requêtes XPath avec préférences structurelles, puis, nous présentons un algorithme d'évaluation des requêtes PrefSXPath à l'aide des automates. ABSTRACT. The concept of bipolar queries (also call preferences queries) emerged in the Relational Databases community, allowing users to get much more relevant responses to their requests, expressed via queries say with preferences. Such requests usually have two parts: the first is used to express the strict constraints and the second, preferences or wishes. Any response to a query with preferences must necessarily satisfy the first part and preferably the latter. However, if there is at least a satisfactory answer of the second part, those satisfying only the first part will be excluded from the final result: they are dominated. In this paper, we explore an approach of importation of this concept in a XML Database via XPath language. To do this, we propose PrefSXPath language, an extension of XPath in order to express XPath queries with structural preferences, then we present a query evaluation algorithm of PrefSXPath using automata.
Photovoltaic Hybrid Systems for remote villages
Authors: Ngundam J.M. , Kenne G. , Nfah Eustace Mbaka 
Published: January 2021

Electricity access in remote areas of Sub-Saharan Africa is limited due to high costs of grid extension to areas characterised by low population and low energy densities. Photovoltaic hybrid systems can be computed using an energy balance equation involving one unknown. For hypothetical village with an average daily energy demand of 153.6 kWh/d, the monthly energy output of photovoltaic modules at Garoua, Cameroon, enabled the evaluation of feasible photovoltaic hybrid (PVHS) options. An option with a renewable energy fraction of 0.557 having lower initial investments is suggested for electrification of more remote villages in Sub-Saharan African countries which have high solar radiation levels. This option comprises a 23.56 kWp PV array, a 15 kWp PV inverter, a 25 kW bi-directional inverter, a battery bank of capacity 324.48 kWh and a 25 kW diesel generator with an operating time of 1309 h/yr or 3.59h/d. The size of the PV array determined is smaller compared to the sizes of PV arrays which have been evaluated in the range 30-45 kWp using HOMER software for medium villages in Senegal.
L’access à l’éléctricité en Afrique Sub-saharienne est limité par le cout élevé d’extension des resaux electriques vers les zones isolées caracterisés par une faible densité de la population et une faible densité de consummation de l’energie electrique. Les systemes hyrides photovoltaiques peuvent étre evalués avec une equation energétique à un inconue. Pour un village hypothetique avec une demande énergétique quotidienne de 153.6 kWh/jr, les productions énergetique mensuelles des modules photovotaiques à Garoua, au Cameroun, ont permis l’evaluation des options photovoltatiques hybrides realisables. Une option avec une fraction d’énergie renouvelable de 0,557 ayant un investment initial inféreur est suggerée pour l’électrification de villages plus éloignés dans l’Afrique subsaharienne qui ont des niveaux élevés de rayonnement solaires. Cette option comprend un générateur photovotaique de 23,56 kWc, un onduleur photovoltaique de 15 kWc, un inverseur bidirectionnel de 25 kW, un groupe de batterie d’une capacité de 324.48 kWh, et un groupe electrogene diesel de 25 kW avec un temps de fonctionnement de 1309 h/an ou 3.59h/j. La taille du générateur photovoltaique determiné est inférieur à celle des générateurs photovoltaiques dans la plage allant de 30 à 45 kWc à l’aide du logiciel HOMER pour les villages moyenne du Senegal comptant 750 habitants.