233 research outputs found

    Evaluation of Robust Feature Descriptors for Texture Classification

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    Texture is an important characteristic in real and synthetic scenes. Texture analysis plays a critical role in inspecting surfaces and provides important techniques in a variety of applications. Although several descriptors have been presented to extract texture features, the development of object recognition is still a difficult task due to the complex aspects of texture. Recently, many robust and scaling-invariant image features such as SIFT, SURF and ORB have been successfully used in image retrieval and object recognition. In this paper, we have tried to compare the performance for texture classification using these feature descriptors with k-means clustering. Different classifiers including K-NN, Naive Bayes, Back Propagation Neural Network , Decision Tree and Kstar were applied in three texture image sets - UIUCTex, KTH-TIPS and Brodatz, respectively. Experimental results reveal SIFTS as the best average accuracy rate holder in UIUCTex, KTH-TIPS and SURF is advantaged in Brodatz texture set. BP neuro network works best in the test set classification among all used classifiers

    Evaluation of Robust Feature Descriptors for Texture Classification

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    Texture is an important characteristic in real and synthetic scenes. Texture analysis plays a critical role in inspecting surfaces and provides important techniques in a variety of applications. Although several descriptors have been presented to extract texture features, the development of object recognition is still a difficult task due to the complex aspects of texture. Recently, many robust and scaling-invariant image features such as SIFT, SURF and ORB have been successfully used in image retrieval and object recognition. In this paper, we have tried to compare the performance for texture classification using these feature descriptors with k-means clustering. Different classifiers including K-NN, Naive Bayes, Back Propagation Neural Network , Decision Tree and Kstar were applied in three texture image sets - UIUCTex, KTH-TIPS and Brodatz, respectively. Experimental results reveal SIFTS as the best average accuracy rate holder in UIUCTex, KTH-TIPS and SURF is advantaged in Brodatz texture set. BP neuro network works best in the test set classification among all used classifiers

    Price competition between shrink-wrap software and cloud service firms under a stochastic model

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    The authors establish a stochastic model of the price competition between shrink-wrap software and cloud service firms. They show that cloud service firms earn higher profits, but face higher risks compared to shrink-wrap software firms. In order to attract customers and earn higher profits, the authors obtain the result that shrink-wrap software firms need to focus on pricing strategies, by contrast, cloud service firms need to focus on quantity strategie

    Relationships between stress, coping and depressive symptoms among overseas university preparatory Chinese students: a cross-sectional study

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    <p>Abstract</p> <p>Background</p> <p>Mental health problems in young people are an important public health issue. Students leaving their hometown and family at a young age to pursue better educational opportunities overseas are confronted with life adjustment stress, which in turn affects their mental health and academic performance. This study aimed to examine the relationships among stress, coping strategies, and depressive symptoms using the stress coping framework in overseas Chinese university preparatory students in Taiwan.</p> <p>Methods</p> <p>A cross-sectional study was conducted at an overseas Chinese university preparatory institute in Taiwan. Of enrolled overseas Chinese university preparatory students at 2009, 756 completed a structured questionnaire measuring stress, strategies for coping with it, and the Center for Epidemiologic Studies Depression Scale.</p> <p>Results</p> <p>High levels of stress significantly predicted the adoption of active, problem-focused coping strategies (<it>R</it><sup>2 </sup>= 0.13<!-- entity --><it>, p </it>< .01) and passive, emotion-focused coping strategies (<it>R</it><sup>2 </sup>= 0.24<!-- entity --><it>, p </it>< .01). Acceptable CFI, SRMR, and RMSEA values from the structural equation modeling analysis demonstrated that the model satisfactorily fits the stress coping framework, after active coping strategies were eliminated from the model. Results from the Sobel test revealed that passive coping strategies mediated the relation between stress and depressive symptoms (<it>z </it>= 8.06, <it>p </it>< .001).</p> <p>Conclusion</p> <p>Our study results suggested that stress is associated with coping strategies and depressive symptoms and passive strategies mediate the relation between stress and depressive symptoms in overseas Chinese university preparatory students.</p

    Evaluation of Antioxidant and Free Radical Scavenging Capacities of Polyphenolics from Pods of Caesalpinia pulcherrima

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    Thirteen polyphenolics were isolated from fresh pods of Caesalpinia pulcherrima using various methods of column chromatography. The structures of these polyphenolics were elucidated as gallic acid (1), methyl gallate (2), 6-O-galloyl-d-glucoside (3), methyl 6-O-galloyl-β-d-glucoside (4), methyl 3,6-di-O-galloyl-α-d-glucopyranoside (5), gentisic acid 5-O-α-d-(6′-O-galloyl)glucopyranoside (6), guaiacylglycerol 4-O-β-d-(6′-O-galloyl)glucopyranoside (7), 3-methoxy-4-hydroxyphenol 1-O-β-d-(6′-O-galloyl) glucopyranoside (8), (+)-gallocatechin (9), (+)-catechin (10), (+)-gallocatechin 3-O-gallate (11), myricetin 3-rhamnoside (12), and ampelopsin (13). All isolated compounds were tested for their antioxidant activities in the 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and peroxynitrite radicals scavenging assays. Among those compounds, 11, 12, and 2 exhibited the best DPPH-, hydroxyl-, and peroxynitrite radical-scavenging activities, respectively. Compound 7 is a new compound, and possesses better scavenging activities towards DPPH but has equivalent hydroxyl radical scavenging activity when compared to BHT. The paper is the first report on free radical scavenging properties of components of the fresh pods of Caesalpinia pulcherrima. The results obtained from the current study indicate that the free radical scavenging property of fresh pods of Caesalpinia pulcherrima may be one of the mechanisms by which this herbal medicine is effective in several free radical mediated diseases

    Fatigue and sleep disturbance related to perceived stress in Chinese HIV-positive individuals: A mixed methods study

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    Background Few studies of HIV+ individuals in China have examined the associations between HIV-related stress with sleep disturbance and fatigue, which are common complaints among people living with HIV/AIDS (PLWHA). We carried out this study to examine the relationships among perceived stress, sleep disturbance, and fatigue in PLWHA in China. Methods A mixed methods study design was used during data collection in Shanghai, China, from December 2009 to March 2010. Qualitative in-depth interviews were conducted with 19 HIV+ females. Additionally, cross-sectional audio computer-assisted self-interviews (ACASI) were conducted to collect quantitative data from a convenience sample of 107 HIV+ patients (84% were male) including the following scales: 1) Perceived Stress Scale for PLWHA, 2) General Sleep Disturbance Scale, and 3) Fatigue Scale. Results The major themes that emerged from the in-depth interviews were around life stress with HIV, sleep disturbance, and fatigue. Participants presented varying amounts of stress around worrying about whether to disclose their diagnosis and whether they might transmit the disease to their family. In addition, in the cross-sectional data, 40% of the participants reported clinically significant sleep disturbances (GSDS \u3e 3) with an average of 3 nights of disturbed sleep in the past week (M=2.87, SD=1.21) and moderate fatigue severity (M=5.24, SD=2.27). In mediation analyses, the data suggests that the relationship between perceived stress and fatigue was largely (53%) mediated through sleep disturbance. Conclusions Chinese PLWHA described how stress had caused them to become sleepless and fatigued. The quantitative data also demonstrated significant levels of sleep disturbance and fatigue, where were due to perceived stress with HIV disease. A systematic self-management intervention to decrease perceived stress should be designed and implemented in mental health resource-limited settings such as China in order to reduce sleep disturbance and fatigue

    Elevated plasma level of visfatin/pre-b cell colony-enhancing factor in male oral squamous cell carcinoma patients

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    Objectives: Visfatin, also known as nicotiamide phosphoribosyltransferase or pre-B cell colony enhancing factor, is a pro-inflammatory cytokine whose serum level is increased in various cancers. In this study, we investigated whether plasma visfatin levels were altered in patients with oral squamous cell carcinoma (OSCC). The relation ship between plasma visfatin levels and the pretreatment hematologic profile was also explored. Study Design: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub- D esign: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub- esign: Plasma visfatin concentrations were measured through ELISA in OSCC patients and control sub jects. A total of 51 patients with OSCC and 57 age- and body mass index (BMI)-matched control subjects were studied. All study subjects were male. Results: Plasma visfatin was found to be elevated in patients with OSCC (7.0 ± 4.5 vs. 4.8 ± 1.9 ng/ml, p = 0.002). Multiple logistic regression analysis revealed visfatin as an independent association factor for OSCC, even after full adjustment of known biomarkers. Visfatin level was significantly correlated with white blood cell (WBC) count, neutrophil count, and hematocrit (all p < 0.05). In addition, WBC count, neutrophil count, and visfatin gradually increased with stage progression, and hematocrit gradually decreased with stage progression (all p < 0.05). Conclusion: Increased plasma visfatin levels were associated with OSCC, independent of risk factors, and were cor related with inflammatory biomarkers. These data suggest that visfatin may act through inflammatory reactions to play an important role in the pathogenesis of OSC

    Natural Product Chemistry of Gorgonian Corals of Genus Junceella—Part II

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    The structures, names, bioactivities, and references of 81 new secondary metabolites obtained from gorgonian corals belonging to the genus Junceella are described in this review. All compounds mentioned in this review were obtained from sea whip gorgonian corals Junceella fragilis and Junceella juncea, collected from the tropical and subtropical Indo-Pacific Ocean
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