1,721,026 research outputs found
Venafro: tre manufatti urbani fra Reperto e Referente
No full textRilievo e rappresentazione di tre manufatti architettonici del centro storico di Venafro: anfiteatro, castello, chiesa dell'Annunziata
Ruolo funzionale e localizzazione sub-cellulare delle proteine Sm e Sm-like nei neuroni
Get PDFSpinal muscular atrophy (SMA) is the most common genetic cause of childhood disease and results
from selective loss of α motor neurons. SMA is caused by mutations or deletions of the telomeric
copy of the survival motor neuron 1 gene (SMN1). This gene is fundamental for the assembly and
regeneration of spliceosomal small nuclear ribonuclear proteins (snRNPs) in all cellular types. The
mechanism by which SMN deletion is responsible of selective neuro-muscular defect and specific
motor neurons degeneration is still unknown, even if some studies suggested an additional neuronspecific
function of the protein.
In this work, we investigated in neurons the role of SMN and LSm1 to LSm7, which is involved in
mRNA degradation in HeLa cells and may well require the SMN protein for assembly and/or
function.
We constructed stable neuroblastoma cell lines by RNA interference that express low level of SMN
protein and can be considered as a pathological model of SMA. We found that decreased expression
of SMN protein does not influence the assembly of snRNPs nor of the LSm1-7 complex. In these
cellular clones, LSm1 protein assembles in the cytoplasm as punctuated structures (P-bodies) that
are also found in control cells and all other cell types. Moreover, SMN knock-down clones showed
an atypical localization of heavy chain neurofilaments (NFH) that fuse in the soma. Overexpressing
SMN in wild type neuroblastoma (SH S5Y5) we observed the presence of aggregates in inclusion
bodies, suggesting the interaction between SMN and NFH. Even if SMN knock-down resemble the
pathological condition of SMA, the level of downregulated protein may be not enough to interfere
with the snRNPs biogenesis. We can speculate that in primary culture neurons exists a different
regulatory pathway. In fact, experiments on neurons from spinal cord, Purkinje cells and
hippocampal neurons demonstrated a mechanism of dendritic localization never seen in cell lines.
We showed for the first time that LSm1 protein, beside to localize in P-bodies in the soma, can
distribute on the dendrites in punctuate structures that contain no degradation enzymes such as
Dcp1a. Further, LSm1 binds specific dendritic mRNAs suggesting an involvement in the mRNA
transport and/or in the local protein synthesis.
In conclusion, we dimostrated that LSm1 can form new complexes with specific neuronal tasks and
hypothesize that the presence of SMN is crucial for the function of these complexes
Disegno e geometria nella cultura del progetto contemporaneo. Le architetture religiose di Mario Botta
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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
A system for automatic image categorization
No full textTraditional multimedia classification techniques are based on the analysis of either low-level features or annotated textual information. Instead, the semantic gap between rough data and its content is still a challenging task. In this paper, we describe a novel solution which automatically associates the image analysis and processing algorithms to keywords and human annotation. We use the well known Flickr system, that contains images, tags, keywords and sometimes useful annotation describing both the content of an image and personal interesting information describing the scene. We have carried out several experiments demonstrating that the proposed categorization process achieves quite good performances in terms of efficiency and effectiveness. © 2009 IEEE
MOWIS: A system for building multimedia ontologies from web information sources
No full textDefining ontologies within the multimedia domain still remains a challenging task, due to the complexity of multimedia data and the related associated knowledge. In this paper, we propose: i) a novel multimedia ontology model that combine both low level descriptors and high level semantic concepts; ii) an automatic construction of ontologies using the Flickrweb services, that provide images, tags, Keywords: and sometimes useful annotation describing both the content of an image and personal interesting information. Eventually, we describe an example of automatic ontology construction in a specific domain. Copyright owned by the authors
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
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