1,720,984 research outputs found
APPROFONDIMENTO DELLE CONOSCENZE SULL'ECOLOGIA DEI DITTERI CHIRONOMIDI DELLE ACQUE INTERNE ITALIANE
Full text linkThe general aim of this work was to study lakes’s benthic communities, particularly Chironomids (Diptera Chironomidae), to select the environmental factors correlated to their diversity and distribution and to provide information about their ecology. A self-organizing map analysis (SOM) was carried out to ordinate sites (samples from 50 Italian lakes) according to macroinvertebrate community composition. Environmental variables were also included in the two dimension maps to highlight which factors are associated with site-taxa distribution (dissolved oxygen and nutrient content were selected). Within species with an indicator role of hypoxia, high nutrient amount, inorganic and organic pollution, the Chironomid Chironomus riparius Meigen 1804 was selected. A first series of experiments were carried out in lab on IV-instar larvae to investigate the role of the respiratory pigment hemoglobin and of the enzyme alcohol dehydrogenase in survive hypoxia and anoxia. A second series of experiments were carried out always on IV-instar larvae to investigate the role of five candidate genes (hsp10, hsp40, hsp70, hsc70 and cyp450) in toxic resistance (Cu and azadirachtin) (Real Time PCR analysis). Overall more information on autoecology of Chironomids was given by this study, and new data on potential biomarkers useful in biomonitoring of lakes
Transcriptional profiling induced by pesticides employed in organic agriculture in a wild population of Chironomus riparius under laboratory conditions
No full textCopper (Cu) and azadirachtin (AZA-A + B) are pesticides allowed in organic agriculture whose environmental risk and toxicity for aquatic wildlife is only partially known. Reverse Transcription Polymerase Chain Reaction was used to assess the molecular effect of acute and short-term exposure (3, 24 h) of Cu (0.01, 0.05, 1, 10, 25 mg l−1) and AZA-A + B (0.2, 0.3, 0.4, 0.5, 1 mg l−1) on the expression of five candidate genes (hsp70, hsc70, hsp40, hsp10 and cyP450) in a non-target species, Chironomus riparius. Fourth-instar larvae were collected from a mountain stream polluted by agricultural land run-off. All genes were responsive to both pesticides but each gene had a specific response to the different experimental concentrations and exposure times. A few similarities in transcriptional profiling were observed, such as a linear concentration-dependent response of hsp70 after 24 h of exposure (at ≥1 mg l−1 of Cu and ≥0.2 mg l−1 of AZA-A + B) and an up-regulation regardless of the concentration of hsc70 after 24 h of exposure (at ≥0 mg l−1 of Cu and ≥0.2 mg l−1 of AZA-A + B and the up-regulation of hsp70 after 3 h of exposure at ~LC50 (Cu-LC50 = 26.1 ± 2.5 mg l−1, AZA-A + B-LC50 = 1.1 ± 0.2 mg l−1). According to the results, hsp40, hsp10 and cyP450 may be defined as pesticide-dependent (i.e., hsp40 and hsp10 seemed to responded mainly to AZA-A + B and cyP450 to Cu), while hsc70 as time-dependent regardless of the pesticide (i.e., hsc70 responded only after 24 h of treatmentwith Cu and AZA-A+B). This study gives new insights on the potential role of the C. riparius's hsps and cyP450 genes as sensitive biomarkers for freshwater monitoring
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
Detection of a case of pseudolymphocytosis due to cryoglobulins
No full textA new type of interference of cryoglobulins on hemocytometric tests is described. The precipitation of temperature-dependent proteins produced a pseudolymphocytosis on a three-part differential leukocyte count of Coulter S-Plus VI, whereas unaffected results, identical to the microscopical count, were obtained using the cytometer Coulter VCS. The laboratory detection of cryoglobulin interference on hematological data is very important in patients with underlying diseases, where the accuracy of absolute and differential leukocyte counts is critical for follow-up. Histograms from the Coulter S-Plus VI can help detect these cases
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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
- …
