1,720,962 research outputs found
Metodo e sistema per rilevare picchi peptidici in segnali HPLC-MS
No full textMediante opportuni algoritmi di elaborazione del dato dallo spettrometro di massa, è stato sviluppato un sistema che indidivua picchi peptidici snche in presenza di rumore sperimentale di divera origine
NOISE CHARACTERISATION AND REJECTION IN HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY COUPLED TO MASS SPECTROMETRY
No full textMethods and system for detecting peptide peaks in HPLC-MS signals
No full textThe present invention relates to a method, a computer tool and a system for detecting peptide peaks in measurement signals generated by HPLC-MS instruments. The method comprises the steps of: providing an intensity column vector (SIC) representative of the elution values at a specific mass value (m/z) of the measurement signal; performing a wavelet decomposition of such values of said intensity column vector (SIC) to generate a first processed vector representative of the smoothed intensity values of the intensity column vector (SIC); providing a threshold value (S) and performing a wavelet decomposition as a function of the value of said threshold (S) to generate the second processed vector representative of said intensity column vector (SIC) cleaned of any oscillations generated by stochastic noise (e(t)); processing said first processed vector and said second processed vector to generate a third processed vector identifying the baseline value of said intensity column vector (SIC); processing said intensity column vector (SIC) and said second and third vectors to generate e filtered vector identifying any peak value (zi) below the background noise.
Method and system for detecting peptide peaks in HPLC-MS signal
Wavelet-based method for noise characterization and rejection in high-performance liquid chromatography coupled to mass spectrometry.
No full textWe present a new method for rejecting noise from HPLC-MS data sets. The algorithm reveals peptides at low concentrations by minimizing both the chemical and the random noise. The goal is reached through a systematic approach to characterize and remove the background. The data are represented as two-dimensional maps, in order to optimally exploit the complementary dimensions of separation of the peptides offered by the LC-MS technique. The virtual chromatograms, reconstructed from the spectrographic data, have proved to be more suitable to characterize the noise than the raw mass spectra. By means of wavelet analysis, it was possible to access both the chemical and the random noise, at different scales of the decomposition. The novel approach has proved to efficiently distinguish signal from noise and to selectively reject the background while preserving low-abundance peptides
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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