1,720,992 research outputs found
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
Biodegradable polymeric nanoparticles administered in the cerebrospinal fluid: Brain biodistribution, preferential internalization in microglia and implications for cell-selective drug release
No full textCell-selective drug release in the central nervous system (CNS) holds great promise for the treatment of many CNS disorders but it is still challenging. We previously demonstrated that polymeric nanoparticles (NPs) injected intra-parenchyma in the CNS can be internalized specifically in microglia/macrophages surrounding the injection site. Here, we explored NPs administration in the cerebrospinal fluid (CSF) to achieve a wider spreading and increased cell targeting throughout the CNS; we generated new NPs variants and studied the effect of modifying size and surface charge on NPs biodistribution and cellular uptake. Intra-cerebroventricular administration resulted in prevalent localization of the NPs in proximity to stem-cell niches, such as around the lateral ventricles, the subventricular zone and the rostral migratory stream. NPs internalization occurred preferentially in brain myeloid cells/microglia. We demonstrated that brain biodistribution and extent of internalization in microglia are influenced by NPs dimensions and can be improved by applying a transient disruption of the blood-brain barrier with mannitol, leading to NPs internalization in up to 25% of brain myeloid/microglia cells. A fraction of the targeted cells was positive for markers of proliferation or stained positive for stemness/progenitor-cell markers such as Nestin, c-kit, or NG2. Interestingly, through these newly formulated NPs we obtained controlled and selective release of drugs otherwise difficult to formulate (such as busulfan and etoposide) to the target cells, preventing unwanted side effects and the toxicity obtained by direct brain delivery of the not encapsulated drugs. Overall, these data provide proof of concept of the applicability of these novel NP-based drug formulations for achieving internalization not only in mature microglia but also possibly in more immature myeloid cells in the brain and pave the way for brain-restricted microglia-targeted drug delivery regimens
Simultaneous Flow Cytometric Characterization of Multiple Cell Types Retrieved from Mouse Brain/Spinal Cord Through Different Homogenization Methods
No full textRecent advances in viral vector and nanomaterial sciences have opened the way for new cutting-edge approaches to investigate or manipulate the central nervous system (CNS). However, further optimization of these technologies would benefit from methods allowing rapid and streamline determination of the extent of CNS and cell-specific targeting upon administration of viral vectors or nanoparticles in the body. Here, we present a protocol that takes advantage of the high throughput and multiplexing capabilities of flow cytometry to allow a straightforward quantification of different cell subtypes isolated from mouse brain or spinal cord, namely microglia/macrophages, lymphocytes, astrocytes, oligodendrocytes, neurons and endothelial cells. We apply this approach to highlight critical differences between two tissue homogenization methods in terms of cell yield, viability and composition. This could instruct the user to choose the best method depending on the cell type(s) of interest and the specific application. This method is not suited for analysis of anatomical distribution, since the tissue is homogenized to generate a single-cell suspension. However, it allows to work with viable cells and it can be combined with cell-sorting, opening the way for several applications that could expand the repertoire of tools in the hands of the neuroscientist, ranging from establishment of primary cultures derived from pure cell populations, to gene-expression analyses and biochemical or functional assays on well-defined cell subtypes in the context of neurodegenerative diseases, upon pharmacological treatment or gene therapy
Evaluation of the remaining hydro potential in Italy
No full textA methodology is described to evaluate the residual hydropower potential in Italy, taking into account the current demand on water resources (irrigation, drinking water, existing hydropower). The model applied uses a numerical technique coupled with a GIS, the hydrological and physiographic characteristics of nearly 1500 interconnected sub-basin, and rainfall maps. Maps of water resources availability and the related maximum hydropower potential have been produced and are fond to be quite helpful tools to support power authorities, decision makers and other stakeholders in creating Energy masterplans, and in implementing small hydro plants
Evaluation of the remaining hydro potential in Italy
No full textA methodology is described to evaluate the residual hydropower potential in Italy, taking into account the current demand on water resources (irrigation, drinking water, existing hydropower). The model applied uses a numerical technique coupled with a GIS, the hydrological and physiographic characteristics of nearly 1500 interconnected sub-basin, and rainfall maps. Maps of water resources availability and the related maximum hydropower potential have been produced and are fond to be quite helpful tools to support power authorities, decision makers and other stakeholders in creating Energy masterplans, and in implementing small hydro plants
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
Simultaneous flow cytometric characterization of multiple cell types retrieved from mouse brain/spinal cord through different homogenization methods
No full textRecent advances in viral vector and nanomaterial sciences have opened the way for new cutting-edge approaches to investigate or manipulate the central nervous system (CNS). However, further optimization of these technologies would benefit from methods allowing rapid and streamline determination of the extent of CNS and cell-specific targeting upon administration of viral vectors or nanoparticles in the body. Here, we present a protocol that takes advantage of the high throughput and multiplexing capabilities of flow cytometry to allow a straightforward quantification of different cell subtypes isolated from mouse brain or spinal cord, namely microglia/macrophages, lymphocytes, astrocytes, oligodendrocytes, neurons and endothelial cells. We apply this approach to highlight critical differences between two tissue homogenization methods in terms of cell yield, viability and composition. This could instruct the user to choose the best method depending on the cell type(s) of interest and the specific application. This method is not suited for analysis of anatomical distribution, since the tissue is homogenized to generate a single-cell suspension. However, it allows to work with viable cells and it can be combined with cell-sorting, opening the way for several applications that could expand the repertoire of tools in the hands of the neuroscientist, ranging from establishment of primary cultures derived from pure cell populations, to gene-expression analyses and biochemical or functional assays on well-defined cell subtypes in the context of neurodegenerative diseases, upon pharmacological treatment or gene therapy
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