1,721,002 research outputs found
Different behaviour between autotrophic and heterotrophic Galdieria sulphuraria (Rhodophyta) cells to nitrogen starvation and restoration. Impact on pigment and free amino acid contents
No full textThe unicellular red alga Galdieria sulphuraria is a polyextremophilic organism with a metabolic flexibility to grow autotrophically or heterotrophically. Galdieria can also produce and accumulate biotechnologically attractive products such as pigments (phycocyanin) and proteins. In this research we studied the effects of nitrogen starvation and its subsequent restoration on pigment and free amino acid contents both in photoautotrophic and heterotrophic cells. Following the nitrogen starvation, the levels of the primary photosynthetic pigments decreased both in autotrophic and heterotrophic cells, except for the chlorophyll a marginally diminished in heterotrophic cells. Ammonium supply to G. sulphuraria N starved cells caused a significant increase of total chlorophylls both in autotrophic and heterotrophic cells. It was observed how such increase was more rapid and marked in heterotrophic cells than in the autotrophic ones. Under N starvation, phycocyanin contents decreased in both autotrophic and in heterotrophic cells; however, after a time-lapse of 24 hours, they resulted significantly higher in heterotrophic cells. In Galdieria sulphuraria, like in other microalgae, free amino acid contents were profoundly dependent on nitrogen status of the cells but heterotrophic cells maintained much higher levels, especially of glutamate, respect to autotrophic ones. In general, cells grown in the presence and absence of light showed different responses toward N availability; in particular heterotrophic cells seemed to respond quicker to the ammonium restoration compared to autotrophic ones
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
Sulfur Starvation in Extremophilic Microalga Galdieria sulphuraria: Can Glutathione Contribute to Stress Tolerance?
Get PDFThis study reports the effects of sulfur (S) deprivation in cultures of Galdieria sulphuraria (Cyanidiophyceae). Galdieria is a unicellular red alga that usually grows, forming biomats on rocks, in S-rich environments. These are volcanic areas, where S is widespread since H2S is the prevalent form of gas. The glutathione content in Galdieria sulphuraria is much higher than that found in the green algae and even under conditions of S deprivation for 7 days, it remains high. On the other hand, the S deprivation causes a decrease in the total protein content and a significant increase in soluble protein fraction. This suggests that in the conditions of S starvation, the synthesis of enzy-matic proteins, that metabolically support the cell in the condition of nutritional stress, could be up regulated. Among these enzymatic proteins, those involved in cell detoxification, due to the accumulation of ROS species, have been counted
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
Cambiamenti di status degli immigrati in Italia: risultati di un record-linkage su fonti amministrative
No full textL’archivio amministrativo dei permessi di soggiorno è una fonte preziosa che consente di avere informazioni sulle principali caratteristiche degli stranieri e delle autorizzazioni a loro concesse. In particolare, appare interessante analizzare i cambiamenti nel tipo di permesso (per motivo e durata del soggiorno) e gli spostamenti territoriali (variazione del luogo di rilascio) che intervengono tra rinnovi successivi. Questi cambiamenti di status non possono essere osservati attraverso i dati di stock disponibili ad una certa data, poiché non risultano disponibili le informazioni sulla situazione pregressa, ma solo quelle relative alla condizione attuale. Per superare questo limite risulta necessario il ricorso a procedure di record-linkage tra archivi relativi a momenti successivi. I dati individuali che l’Istat riceve periodicamente dal Ministero dell’Interno non sono però nominativi, anche se è possibile procedere ad una individuazione pressoché univoca dei titolari dei permessi attraverso la disponibilità o la creazione di un codice identificativo. Il record-linkage tra gli archivi dei permessi di soggiorno è stato realizzato con successo per gli anni compresi nell’intervallo che va dall’inizio del 2004 all’inizio del 2007. L’inizio del 2004 è la data appena successiva alla concessione dei permessi di soggiorno a seguito della regolarizzazione collegata alla legge Bossi-Fini che ha consentito di entrare nella regolarità a circa 650.000 stranieri irregolari. Obiettivo dell’analisi è seguire i regolarizzati nei tre anni successivi alla sanatoria (2004-2006) per valutare la permanenza nella regolarità e i cambiamenti di status intervenuti. I risultati del record-linkage consentono difatti di dare risposta ad alcuni interrogativi riguardanti, in particolare, le transizioni sul mercato del lavoro e gli spostamenti all’interno del paese da parte dei regolarizzati ancora presenti in modo regolare sul territorio italiano al termine del periodo considerato.
*** The administrative database of valid permits to stay is a mine of information on personal characteristics of immigrants. In particular, it is interesting to analyze the changes in the type of permit (by reason and duration of stay) and territorial mobility (place of issue) between subsequent authorizations. These changes of status cannot be observed with annual stock data, which do not report the previous situation, but only the present one. Therefore, a linkage between databases of subsequent years is needed. Ministry of Interiors provides Istat with individual but not nominative data, identified by an unique code generated by an ad hoc procedure. As it was changed several times over the years, following various reorganizations of administrative procedures and database design, it is possible to use it only for some specific years. The record linkage has been successfully carried out for the years within the period between the beginning of 2004 and 2007. The beginning of 2004 is the data just after the regularization linked to Bossi-Fini law which allowed about 650,000 irregular foreigners to obtain a valid permit to stay. Objective of the analysis is to follow up the regularized foreigners in the three years after the amnesty (period 2004-2006). Result of the record-linkage allow an in-depth analysis of transitions in and out the labour market and of other migratory paths, including territorial mobility of the regularized foreigners legally living in Italy
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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