3,170 research outputs found

    Human pol II promoter prediction: time series descriptors and machine learning

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    Although several in silico promoter prediction methods have been developed to date, they are still limited in predictive performance. The limitations are due to the challenge of selecting appropriate features of promoters that distinguish them from non-promoters and the generalization or predictive ability of the machine-learning algorithms. In this paper we attempt to define a novel approach by using unique descriptors and machine-learning methods for the recognition of eukaryotic polymerase II promoters. In this study, non-linear time series descriptors along with non-linear machine-learning algorithms, such as support vector machine (SVM), are used to discriminate between promoter and non-promoter regions. The basic idea here is to use descriptors that do not depend on the primary DNA sequence and provide a clear distinction between promoter and non-promoter regions. The classification model built on a set of 1000 promoter and 1500 non-promoter sequences, showed a 10-fold cross-validation accuracy of 87% and an independent test set had an accuracy >85% in both promoter and non-promoter identification. This approach correctly identified all 20 experimentally verified promoters of human chromosome 22. The high sensitivity and selectivity indicates that n-mer frequencies along with non-linear time series descriptors, such as Lyapunov component stability and Tsallis entropy, and supervised machine-learning methods, such as SVMs, can be useful in the identification of pol II promoters

    DCE-MRI and parametric imaging in monitoring response to neoadjuvant chemotherapy in breast carcinoma : a preliminary report

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    Purpose: Neoadjuvant chemotherapy is recommended in patients with locally advanced breast cancer. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) enables evaluation of the tumour neovasculature that occurs prior to any volume change, which helps identify early treatment failures and allows prompt implementation of second-line therapy. Material and methods: We conducted a prospective study in 14 patients with histopathologically proven breast cancer. DCE-MRI data were acquired using multisection, T1-weighted, 3D vibe sequences with fat suppression before, during, and after IV bolus injection (0.1 mmol/kg body weight, Gadoversetamide, Optimark). Post-processing of dynamic contrast perfusion data was done with the vendor's Tissue 4D software to generate various dynamic contrast parameters, i.e. Ktrans, Kep, Ve, initial area under the time signal curve (IAUC), apparent diffusion coefficient (ADC), and enhancement curve. Patients underwent MRI examinations at baseline, and then after two cycles, and finally at completion of chemotherapy. Results: Based on Sataloff criteria for pathological responses, four patients out of 14 were responders, and 10 were non-responders. At the 2nd MRI examination, IAUC was significantly smaller in responders than in non-responders (p = 0.023). When the results of the first and second MRI examinations were compared, Kep decreased from baseline to the second MRI (p = 0.03) in non-responders and in responders (p = 0.04). This change was statistically significant in both groups. The ADC values increased significantly in responders from baseline to the third MRI (p = 0.012). Conclusions: In our study, IAUC and ADC were the only parameters that reliably differentiated responders from non-responders after two and three cycles of chemotherapy

    JWST NIRSpec Cryogenic Light Shield Mechanism

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    The focal plane detectors for the Near-Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST) require a light tight cover for calibration as well as an open field-of-view during ground performance testing within a cryogenic dewar. In order to achieve the light attenuation requirements when closed as well as provide a open field of view for the detectors within the cryogenic dewar, a light shield mechanism was designed. This paper discusses the details of the light shield mechanism design, development, and test results

    Balloon dilatation of isolated severe tricuspid valve stenosis

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    AbstractTricuspid valve stenosis is mostly rheumatic in origin. It almost always occurs in association with mitral valve disease. There are only few case reports of isolated tricuspid valve stenosis. We report a case of isolated tricuspid valve stenosis, which was treated with balloon dilatation

    JWST NIRSpec Cryogenic Light Shield Mechanism

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    The focal plane detectors for the Near-Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST) require a light tight cover for calibration along with an open field-of-view during ground performance testing within a cryogenic dewar. In order to meet the light attenuation requirements and provide open and closed fields of view without breaking vacuum, a light shield mechanism was designed. This paper describes the details of the light shield mechanism design and test results. Included is information on the labyrinth light path design, motor capability and performance, dry film lubrication, mechanism control, and mechanism cryogenic performance results

    JWST NIRSpec Cryogenic Light Shield Mechanism

    Get PDF
    The focal plane detectors for the Near-Infrared Spectrometer (NIRSpec) instrument on the James Webb Space Telescope (JWST) require a light tight cover for calibration along with an open field-of-view during g round performance testing within a cryogenic dewar. In order to meet the light attenuation requirements and provide open and closed fields of view without breaking vacuum, a light shield mechanism was designe d. This paper describes the details of the light shield mechanism design and test results. Included is information on the labyrinth light p ath design, motor capability and performance, dry film lubrication, m echanism control, and mechanism cryogenic performance results

    The United Nations Convention on Contracts for the International Sale of Goods: The Canadian Experience

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    The author discusses the Canadian jurisprudence involving the application, or potential application, of the CISG.  He concludes that the Canadian courts are beginning to implement the CISG, but that there is still a tendency to apply domestic law alongside, or even in preference to, the international sales law, even when this is not warranted

    Diversification in rural livelihood strategies : a macro-level evidence from Jammu and Kashmir

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    Agricultural sector is predominant in the economy of Jammu and Kashmir and provides livelihood to the majority of the population. The overall economic growth of the state depends largely on the progress of agricultural sector, since only a very nominal progress has been achieved in the secondary as well as in the tertiary sectors. It is well recognized that the livelihood of those dependent on agricultural sector is unsustainable which necessitates the creation of supplementary sources to raise it to a sustainable level. Household livelihood diversification is a strategy to minimize risk and uncertainty. In the case of fragile region like Jammu and Kashmir, this strategy is especially important. This paper attempts to understand broadly the dynamics of rural livelihood diversification in the state of Jammu and Kashmir. The paper makes use of secondary sources of information to realize the objectives of the study. The findings are that agriculture remains as a dominant livelihood strategy among workers in the state despite the shift to manufacturing and tertiary activities over the period, that is, 1983 to 2004-05. So, it becomes necessary to organize state agriculture in such a manner that the limited land resource is made to yield maximum returns through the application of modern technology. This would increase the well-being of those dependent on agricultural sector for their livelihood. This paper also throws up some issues, which one can delineate further at microlevel. Key Words: Livelihood Diversification, Coping Strategies, Capital Assets, Occupational Structure, Jammu and Kashmir. Jel Classification: Q, Q 0
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