1,721,050 research outputs found
A novel approach for optimizing packet access schemes in non-geostationary satellite systems
No full textThis paper deals with an optimized packet access scheme depending on traffic load conditions that is able to support efficiently three traffic classes (voice, Web interactive and short messages) in non-geostationary mobile satellite systems. We adopt the equilibrium point analysis in order to study the stability of our scheme. This allows identifying optimal values for the protocol control parameters. Extensive comparisons have been performed with other techniques in the literature showing the good results achieved by our protocol
Stability analysis of an access scheme for mixed traffics in LEO and MEO systems
No full textThis paper deals with the stability analysis of a packet access scheme able to support efficiently three traffic classes (voice, Web interactive and short messaging) in LEO and MEO mobile satellite systems. This study permits to select optimized permission probability values; accordingly, our access scheme has been named Optimized Packet Reservation Multiple Access (O-PRMA). Its good performance has been also shown in the presence of a GOOD-BAD channel model
Flow cytometry and oncohematology: A relationship bound to last | [Citometria a flusso ed ematologia oncologica: Un matrimonio sempre valido]
No full textThe contribution of flow cytometry to the diagnosis and follow-up of hematological neoplasms is of paramount importance and cannot be overstressed. Today, this relationship is not questioned and it is unlikely that the new molecular techniques will be able to replace it shortly. The reason of this long lasting success relies on the importance of phenotype in the diagnostic work-out, but above all on the flexibility of the technique, which is able to produce clinically relevant information in different situations, using smart fluorescence-based method
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
CYTOFLUOROMETRIC IDENTIFICATION OF 2 POPULATIONS OF DOUBLE POSITIVE (CD4+,CD8+) T-LYMPHOCYTES IN HUMAN PERIPHERAL-BLOOD
No full textTwo different subsets of CD4+,CD8+ T lymphocytes have been identified in peripheral blood collected from normal subjects and from patients with different diseases. The subpopulations differed in the degree of CD4 and CD8 antigen expression. Hence, it was possible to distinguish by cytofluorimetric analysis cells with a low (dim) or with a high (bright) fluorescence intensity after the staining with anti-CD4 or anti-CD8 mAbs. CD4+dim,CD8+bright lymphocytes were found in patients with EBV-infectious mononucleosis and were present for less than a month. CD4+bright,CD8+dim T cells were observed in neoplastic patients as well as in healthy subjects and were continuously present in similar percentages over a long period of time (at the moment, about 3 years). Both the subpopulations expressed CD2, CD3, CD5 antigens and had an alpha beta-TCR, but did not express CD1a or CD7. Only CD4+dim,CD8+bright cells expressed HLA-DR antigen and the activation marker CD38, while only CD4+bright,CD8+dim lymphocytes expressed CD56 and CD57 molecules. The hypothesis may be put forward that these two subsets represent an effort of the immune system to cope with different requirements, i.e., of viral or neoplastic origin, while it is not clear the meaning of these cells in healthy subjects
NATURAL CYTOTOXICITY IN A FRESH-WATER PULMONATE MOLLUSK - AN UNORTHODOX COMPARATIVE APPROACH
No full textCytometric analysis of immunosenescence
No full textWe have been studying the immune system of healthy centenarians for many years, and they provide the best example of successful aging, They are people who have escaped major age-related diseases and reached the extreme limit of human life in good clinical condition, in most cases, histories of centenarians reveal them to be free of cancer, dementia, diabetes, cardiovascular diseases, and cataracts. Moreover, in order to reach such an advanced age, they should be equipped with well preserved and efficient immuno- and defense mechanisms, and optimal combinations of an appropriate lifestyle and genetic background. Using this approach, several paradoxes emerged as far as the immune system of centenarians is concerned, regarding: i) humoral immunity increase in plasma immunoglobulins and nonorgan-specific autoantibodies, decrease in B cell number and lack of organ-specific autoantibodies); ii) cellular immunity (cell preserved number of ́ ́virgin ́ ́ T cells, a relatively intact T cell repertoire despite a thymus involuting since puberty, increased number of cells with markers of NK activity); iii) decreased peripheral blood lymphocyte tendency to programmed cell death, associated with a well preserved mitochondria functionality and intracellular bcl-2 levels, An age-related increase in the levels of adhesion molecule present on lymphocyte plasma-membrane, accompanied by a complex reshaping of the cytokine network, must be added to this scenario, All our data fit the hypothesis that a complex, unpredicted remodelling of the immune system occurs with age. In the present review it is underlined how flow cytometry has been used to study most of the above mentioned aspects of immunosenescence, and to establish new age-related reference values. Cytometry 27:297-313, 1997
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