Face recognition has become an accessible issue for experts as well as ordinary people as it is a focal non-interfering biometric modality. In this paper, we introduced a new approach to perform face recognition under varying facial expressions. The proposed approach consists of two main steps: facial expression recognition and face recognition. They are two complementary steps to improve face recognition across facial expression variation. In the first step, we selected the most expressive regions responsible for facial expression appearance using the Mutual Information technique. Such a process helps not only improve the facial expression classification accuracy but also reduce the features vector size. In the second step, we used the Principal Component Analysis (PCA) to build EigenFaces for each facial expression class. Then, a face recognition is performed by projecting the face onto the corresponding facial expression Eigenfaces. The PCA technique significantly reduces the dimensionality of the original space since the face recognition is carried out in the reduced Eigenfaces space. An experimental study was conducted to evaluate the performance of the proposed approach in terms of face recognition accuracy and spatial-temporal complexity.
Mycotoxins are secondary metabolites produced by filamentous fungi detected in food, such are grapes. OTA was evaluated in ten handle musts from different Tunisian vineyard. This mycotoxin was found at levels 1.1 mug/L to 4.3 mug/L. A survey was conducted to assess the contamination of the Tunisian vineyard with pathogenic fungal species, in particular those responsible of the OTA production. The results were evaluated for the first time in parcels cultivated in the North, in the Centre and in the South of the country. Italia Muscate and Superior Seedless varieties were concerned at three developmental stages of the berry, setting, veraison and maturity. Carigon variety was used as positive control for musts contaminating by OTA. The main fungal species isolated were Aspergillus spp. (33.32%), Botrytis cinerea (23.32%), Alternaria spp. (12.80%), Cladosporium spp. (10.59%) and Penicillium spp. (8.3%). The isolates of the Aspergillus genus were identified as Aspergillus niger aggregate (77%), Aspergillus carbonarius (15%) and Aspergillus flavus (8%). Their presence was characterized by a significant decrease in the Centre during the veraison and a slight increase in the North and the South during the maturity stage. Furthermore, when comparing Superior Seedless and Italia Muscate cultivated in the same area, the aspergilli were particularly less abundant at the setting stage in the case of Superior Seedless. There is no correlation between the OTA amount in musts and the contamination by Aspergillus species in different vineyards and for grape varieties studied. 相似文献
Journal of Materials Science: Materials in Electronics - In the present work, pure BiFeO3 and pure Bi2Fe4O9 single phases were successfully synthesized by tailoring hydrothermal synthesis route.... 相似文献
The objective of this study was to investigate the chemical composition of the essential oils from citrus species, as well as their antioxidant and antimicrobial activities. By gas chromatography-mass spectrometry, we identified thirty-seven metabolites and a range of unique compounds, contributing to the discrimination of the species. Different biological potentialities were detected depending on the species supported the significant effect of the genetic factor. C. aurantium and C. limon exhibited the highest antioxidant activities which make them a potential source of natural preservative. C. limon exhibited the highest antibacterial activities and C. reticulata the highest antifungal activities. Essential oils extracted from these agro-wastes could serve as natural food preservatives to prevent food pathogens and then extending the shelf life. A set of potential metabolites could be implicated in the observed biological activity, underlying that the antimicrobial activity is a complex trait. 相似文献
In this study, 51 samples of cereals (wheat, Barley, maize and Sorghum) and by-products (mainly pasta and couscous) purchased from Tunisian supermarkets were examined for contamination with the emerging Fusarium mycotoxins: Enniatins ENs (EN A, EN A1, EN B and EN B1), beauvericin (BEA) and fusaproliferin (FUS).The extraction of the samples was performed with methanol using an Ultra-turrax homogenizer. Mycotoxins were analyzed with a liquid chromatography (LC) coupled to a diode array detector (DAD).The frequencies of contamination of total samples with ENs were 96%. EN A1 was the most common EN found with the highest prevalence of 92.1%, levels ranged between 11.1 and 480 mg/kg. EN B was evidenced in 35 samples and levels ranged from 1.5 to 295 mg/kg. EN B1 was detected in 20 samples (39.2%) and levels varied from 4.8 to 120.1 mg/kg and EN A was detected in 14 samples with contamination levels ranging between 19.6 and 121.3 mg/kg. The maximum concentration of total ENs in a single sample was 683.9 mg/kg (sorghum). The analytical results also showed that all the analyzed samples were free of BEA and FUS.The present work is the first one ever drafted on the presence of the emerging Fusarium mycotoxins in Tunisian cereals and derived products. 相似文献
The structure and magnetic properties of ball-milled and subsequently annealed Sm2Fe17–xMx compounds (M = Si, Ga, Co, Cr, Zr, Mo, for x = 2) were investigated by X-ray diffraction coupled with magnetic measurements and Mössbauer spectroscopy. Rietveld analysis have shown that all these samples crystallize in the Th2Zn17 type rhombohedral structure. The substituting elements Si, Ga, Co occupy the 18h atom site, while Cr, Zr, Mo prefer the 6c site. Mössbauer studies corroborate these results. The X-ray analysis cannot solve the possible M atom distribution over Fe atom sites when atomic factors of Fe and M are close. Mössbauer spectroscopy appears as the efficient tool to raise this ambiguity. The Curie temperature increases upon Zr and Cr substitution reaching a maximum for x = 1, then decreases because of magnetic dilution. 相似文献
Cereals contamination with mycotoxigenic species of Fusarium is considered as a major source of trichothecenes and other mycotoxin groups which cause severe yield losses and serious diseases in human and animal health. Early detection of Fusarium species could be for a great interest to prevent mycotoxin contaminating agro-products.We have established for the first time a direct polymerase chain reaction (DPCR) protocol to detect contamination with trichothecene-producing F. culmorum in wheat samples. We have successfully amplified fungal genomic DNA using specific primers targeting the trichothecenes biosynthetic Tri5 gene. We further investigated a versatile multiplex-DPCR on the basis of Tri5 gene and IGS (Intergenic Spacer of rDNA) specific sequence of F. culmorum for its identification at specie level and prediction of its potential trichothecenes production simultaneously. Our protocol allowed amplification directly from crude templates with no need of DNA extraction or purification methods and did not require any culture-based approach.These DPCR assays represent a reliable tool for high throughput screening, detection and rapid characterization of mycotoxigenic isolates as well as diverse applications in food industry. 相似文献