2,335 research outputs found

    Morphological studies of gamma-ray sources with IACT arrays

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    The potential of a next-generation ground-based gamma-ray telescope to perform morphological studies of celestial gamma-ray sources is investigated. With this aim, general analytical expressions for the instrument response are derived and simulations of isolated source are used as a benchmark to understand the telescope performance. The morphology is represented assuming an ideal Gaussian point spread function (PSF) and a non-Gaussian PSF with extended tails. The response of the telescope is also tested in case of complex environments. In particular, the effect of locating the source (i) nearby a second one and (ii) on top of a diffuse halo-type object is investigated. The first scenario is particularly interesting in the framework of Galactic objects, where the presence of more than one single source in the same field of view (FoV) is expected. The latter represents a relevant study in the contest of extended extra-galactic sources surrounding AGNs

    Effects of lung volume reduction surgery for emphysema on glycolipidic hormones

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    BACKGROUND: Pulmonary emphysema is associated with cachexia and disregulation of the hormones regulating the glycolipid metabolism, insulin resistance, and altered substrate utilization. This study aimed at identifying the effects of lung volume reduction surgery (LVRS) on glycolipidic hormones compared to respiratory rehabilitation (RR). METHODS: Thirty-three patients with moderate-to-severe emphysema who were undergoing video-assisted thoracoscopic LVRS were compared to 31 similar patients who refused the operation and followed a standardized RR program. All patients were evaluated before and 12 months after treatment for respiratory function, body composition, glycolipidic hormones, metabolic parameters, and insulin resistance, which was calculated using the homeostatic model assessment index for insulin resistance (HOMA-IR). These groups were compared to a matched healthy control population. RESULTS: Only after LVRS significant improvements were obtained in respiratory function (FEV1, +25.2%; p<0.0001; residual volume, -19.5%; p<0.0001), metabolic parameters (total cholesterol, +13.1%; p<0.01; high-density lipoprotein cholesterol, +11.2%; p<0.01; triglycerides, +18.4; p<0.001; nonesterified fatty acid, -19.7%; p<0.001), and body composition (fat-free mass [FFM], +6.5%; p<0.01; fat mass [FM], +11.9%; p<0.01). The leptin/FM ratio (-6.1%; p<0.01) and resistin/FM ratio (-5.6%; p<0.01) decreased, whereas the adiponectin/FM ratio (+6.9%; p<0.01) and ghrelin (+9.2%; p<0.01) increased, together with reductions in glycemia (-8.8%; p<0.01), insulin level (-20.4%; p<0.001), and HOMA-IR (-27.2%; p<0.0001). The decrement in residual volume was correlated with increment of FFM (rho=-0.49; p<0.02), FM (rho=-0.55; p<0.009), and ghrelin (rho=-0.52; p<0.01), and also with decreases in leptin corrected for FM (rho=0.50; p<0.02) and, marginally, HOMA-IR (rho=0.35; p=0.07). CONCLUSIONS: After LVRS, glycolipidic hormone levels and nutritional status significantly improved, along with insulin resistance reduction and more physiologic utilization of substrates. Correlations between residual volume and body composition as well as glycolipidic hormone levels suggest that postoperative recovery in respiratory dynamics may induce favorable clinical changes when compared to RR

    Thymomas: a review.

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    Thymomas are neoplasma of thymic epithelial cells. They may be benign or malignant and may associate with locai ìnvasiveness and paraneoplastic diseases. Myasthenia gravis is often associated with thymomas, bui this is not thè rule. Several classifications have been proposed: some of them follow thè histopathological findings (Rosai and Levine, Snover, Marino and Muller- Hermelink classification), other emphasizes thè clinic-pathological stage (Masaoka, Verley and Hollmann stadiation). One third of thymomas is asymptomatic. Diagnosis is made often by plain X-ray and confirmed by Computed Tomography or fine needle biopsy. Surgery is effective in 100% of noninvasive cases and in 58% of invasive ones. Radio and chemotherapy are recommended only in advanced or inoperable stages

    Classification of non-indigenous species based on their impacts: Considerations for application in marine management

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    Assessment of the ecological and economic/societal impacts of the introduction of non-indigenous species (NIS) is one of the primary focus areas of bioinvasion science in terrestrial and aquatic environments, and is considered essential to management. A classification system of NIS, based on the magnitude of their environmental impacts, was recently proposed to assist management. Here, we consider the potential application of this classification scheme to the marine environment, and offer a complementary framework focussing on value sets in order to explicitly address marine management concerns. Since existing data on marine NIS impacts are scarce and successful marine removals are rare, we propose that management of marine NIS adopt a precautionary approach, which not only would emphasise preventing new incursions through pre-border and at-border controls but also should influence the categorisation of impacts. The study of marine invasion impacts requires urgent attention and significant investment, since we lack the luxury of waiting for the knowledge base to be acquired before the window of opportunity closes for feasible management

    The enlargement of the Suez Canal and introduction of non-indigenous species to the Mediterranean Sea

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    The Suez Canal is one of the most important waterways in the world – during the last year 17,148 ships passed through the Canal – reducing emissions, saving time, and operating costs to shippers. The rapid increase in ship size from the “Post-Suezmax” (> 12,000 TEU) to the latest container vessels (> 19,000 TEU) now requires enlargements of port facilities and canals. A project of this magnitude, and with potentially negative environmental outcomes, requires a transparent and scientifically sound “Environmental Impact Assessment” (EIA). An explicit obligation on Parties to the Convention on Biological Diversity (https://www.cbd.int/doc/ legal/cbd-en.pdf) was made to consider transboundary impacts on biodiversity, particularly those associated with invasive non-indigenous species

    Normative and validation data of an articulation test for Italian-speaking children

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    Objectives: As a standardized instrument to assess speech sound development in Italian-speaking children is currently lacking, norms used to diagnose speech sound disorders (SSD) are mainly based on studies including English-speaking participants. This application may result in misidentification of SSD due to linguistic differences. The aims of the study were to establish normative data on speech sound development of Italian-speaking children and to evaluate psychometric properties of Rossi's articulation test, the picture-naming test selected to assess speech sound development. Methods: A cross-sectional study including 694 normally-developing Italian-speaking children aged from 3 to 7 years was conducted. Children were administered Rossi's articulation test, and percentages of speech sound correct production were calculated. To evaluate inter-rater reliability of the test, audio-recordings of 50 children were scored by an additional examiner. The same rater scored the audio-recordings of 50 children twice with an interval of at least 1 week. To evaluate test-retest reliability, 144 participants were re-tested after 1-3 weeks by the same assessor. Scores were compared through Intraclass Correlation Coefficient (ICC). To assess construct validity, the developmental progression of total scores across age groups was verified by the estimation of the reference range for the test, using a regression procedure. Results: Almost all Italian children in the sample produced vowels and approximants correctly. Singleton consonants were acquired before consonant clusters. Ages of acquisition of each consonant were presented: plosives and nasals were early mastered by Italian children, while dental affricates, alveolar fricatives and the palatal lateral were the latest acquired segments. All ICCs were superior to 0.9 (reliability). A statistically significant improvement in test score with age was found (construct validity). Conclusions: The paper provides normative data for speech sound development of Italian-speaking children; preliminary psychometric analysis of Rossi's articulation test revealed satisfactory reliability and construct validity. Clinicians are recommended to use Rossi's articulation test to assess speech sound development in Italian children

    The Relationship between Socioeconomic Status and Narrative Abilities in a Group of Italian Normally Developing Children

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    OBJECTIVE: Only limited and conflicting information is available regarding the relationship between socioeconomic status (SES) and narrative abilities. Besides, the role fathers' SES plays in the development of their children's narrative abilities has never been investigated. The aim of this study was to analyze the relationship between fathers' and mothers' SES and narrative abilities of their children assessed with the Italian version of the Bus Story Test (I-BST). SUBJECTS AND METHODS: A total of 505 normally developing Italian children were enrolled in the study. Information regarding parents' educational level and employment was collected for each child. Narrative abilities were evaluated using the I-BST. The relationships between parents' employment, educational level, and I-BST scores were analyzed by univariate and multivariate regression analysis. RESULTS: In univariate analysis, both fathers' and mothers' education and employment were associated with most I-BST subscale scores, especially when higher educational and employment levels were contrasted with the lowest educational and employment levels. In multiple regression analysis, significant associations were found only between the fathers' working status and educational level and I-BST subscale scores. CONCLUSIONS: Parental education and employment might impact narrative abilities of children. When both fathers' and mothers' SES variables are considered together, only fathers' education and working status seemed to be associated with I-BST scores

    Parametric and nonparametric two-sample tests for feature screening in class comparison : a simulation study

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    Background: The identification of a location-, scale- and shape-sensitive test to detect differentially expressed features between two comparison groups represents a key point in high dimensional studies. The most commonly used tests refer to differences in location, but general distributional discrepancies might be important to reveal differential biological processes. Methods: A simulation study was conducted to compare the performance of a set of two-sample tests, i.e. Student's t, Welch's t, Wilcoxon-Mann-Whitney (WMW), Podgor-Gastwirth PG2, Cucconi, Kolmogorov-Smirnov (KS), Cramervon Mises (CvM), Anderson-Darling (AD) and Zhang tests (ZK, ZC and ZA) which were investigated under different distributional patterns. We applied the same tests to a real data example. Results: AD, CvM, ZA and ZC tests proved to be the most sensitive tests in mixture distribution patterns, while still maintaining a high power in normal distribution patterns. At best, the AD test showed a power loss of ~ 2% in the comparison of two normal distributions, but a gain of ~ 32% with mixture distributions with respect to the parametric tests. Accordingly, the AD test detected the greatest number of differentially expressed features in the real data application. Conclusion: The tests for the general two-sample problem introduce a more general concept of 'differential expression', thus overcoming the limitations of the other tests restricted to specific moments of the feature distributions. In particular, the AD test should be considered as a powerful alternative to the parametric tests for feature screening in order to keep as many discriminative features as possible for the class prediction analysis

    ICES Viewpoint background document: Evaluating and mitigating introduction of marine non-native species via vessel biofouling

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    Biofouled vessels create novel, mobile habitats characterized by great abundances of opportunistic and non-native species. Vessel biofouling1 affects the environment as well as the economics of vessel management..
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