1,720,970 research outputs found
Validation of Nuclear Magnetic Resonance Experiments Used in Food Certification
Full text linkNonostante i vantaggi derivanti dall'utilizzo della risonanza magnetica nucleare e nono-stante la pletora di processi di validazione ben documentati (precisione, accuratezza, li-nearità, riproducibilità, robustezza, selettività e specificità), pochissimi metodi ufficiali ba-sati su questa tecnica sono noti. Con l'obiettivo di estendere l'uso dell’ NMR nei metodi ufficiali, è stato organizzato il primo confronto interlaboratorio (ILC) internazionale per il fingerprinting del grano e della farina, secondo la normativa ISO/IEC 17043:2010 e altri ri-ferimenti normativi in vigore. ILC fornisce standard oggettivi per laboratori individuali, permettere loro di confrontare i risultati analitici provenienti da diversi laboratori e rappre-senta un modo per controllare la qualità e la precisione del lavoro analitico. La validazione mediante ILC è il punto di partenza per il riconoscimento ufficiale di metodi analitici. 39 NMR data set sono stati prodotti da 37 partecipanti, provenienti da tutto il mondo, con un totale di 46 spettrometri. Al fine di rendere il metodo NMR ufficialmente riconosciuto, i da-ti NMR devono essere elaborati statisticamente secondo le normative europee di riferi-mento. Le prestazioni di ogni laboratorio sono state valutate mediante z-score, parametro relativo alla deviazione standard. I laboratori con uno z-score all’ interno del range di ac-cettabilità sono in grado di garantire prestazioni soddisfacenti. I risultati indicano che l'e-sperimento NMR (1H 1D NOESY) proposto in questo ILC è robusto. Infatti, la maggior parte degli spettri NMR prodotti nel confronto può essere considerata "statisticamente equivalente". Dal momento che nessun precedente rapporto è disponibile per una valuta-zione comparativa dei risultati, in questa fase è opportuno mettere in evidenza alcune possibili criticità, tenendo conto dei valori% CV raccolti in questo ILC. Il passo successi-vo in questa direzione è stata la validazione della procedura di elaborazione degli spettri. Tutti gli spettri ottenuti da questo ILC sono stati elaborati mediante software Mnova con 2 modi differenti di calcolo e con Top Spin, ancora una volta.Despite the advantages deriving from the use of NMR and despite the plethora of well documented validation processes (e.g., precision, accuracy, linearity, reproducibility, ro-bustness, selectivity, and specificity), very few official NMR based quantification meth-ods are known. With the aim to extend the use of NMR in official methods, NMR inter-laboratory comparison (ILC) for fingerprinting of on wheat and flour, was organized ac-cording to ISO/IEC 17043:2010 and reference normative therein. ILC provide objective standards for individual laboratories, permit them to compare analytical results from dif-ferent laboratories and represent a way to check the quality and the accuracy of the ana-lytical job. Validation by ILCs is the starting point for official recognition of the analytical methods. The aim of this inter-laboratory comparison was the validation of a fingerprinting NMR method for classification of wheat and flours. 39 NMR data sets were produced by 37 participants, from all over the world, using 46 spectrometer. In order to make a NMR method officially recognized, NMR data should be statistically processed according to European reference normative. The performance of each laboratory was assessed by means of a z-score which is related to the standard deviation. Laboratories endowed with z-score falling within the suitable acceptability range are able to guarantee a satisfactory performance. Results indicate that the NMR experiment (1D 1H NOESY) proposed for the fingerprinting of wheat and flour aqueous extracts is a robust experiment. In fact, the ma-jority of the participants produced NMR spectra that can be considered “statistically equivalent”. Thus, the main goal of this inter-laboratory comparison, the validation of the 1D 1H NOESY experiment, was achieved along with the indication of the participants able to produce NMR spectra with the highest possible performances. Since no previous report is available for a comparative evaluation of the results, at this stage it is advisable to highlight some possible critical points taking into account the CV% values collected in this ILC. The ulterior step in this direction was the validation of spectra processing proce-dures. All spectra obtained from this ILC were processed with Mnova Software with 2 dif-ferent ways of calculation and with Top Spin once again
Chromium-Containing Organic Fertilizers from Tanned Hides and Skins: a Review on Chemical, Environmental, Agronomical and Legislative Aspects
No full textA category of chromium (Cr)-containing fertilizers is represented by the fertilizers deriving from byproducts of tanning process. Their use is widespread because of their good agronomic response due to the high content of slow release organic nitrogen (N) and carbon. They do not represent an environmental hazard because only the non-toxic form of Cr(III) is present. Productive processes may involve chemical, enzymatic or thermal hydrolysis. The final product is
characterized by different contents of peptides and free amino acids depending on the type of hydrolysis. Legislations concerning Cr-containing fertilizers is controversial because often do not consider any scientific evidences; nevertheless, the European Union, the United States and countries as Italy, do not set the restriction to Cr(III) and generally only the presence of the toxic form, Cr(VI), is limited. Depending on its two main oxidation forms, Cr issue has been studied for many years. Several authors confirmed that Cr(VI) is carcinogenic, while Cr(III) is an essential trace element in human and animal diet. In soil Cr(III) has low mobility, whereas Cr(VI) is highly water soluble. However Cr(VI) in soil is quickly reduced to Cr(III); on the contrary oxidation of Cr(III) to Cr(VI) is rarely possible because particular conditions must occur. Only a very small fraction of Cr in soil is available to plant uptake and its translocation in edible parts is limited because it is immobilized in roots as Cr(III). Therefore risks of environmental pollution using these fertilizers are negligible; on the contrary they have positive environmental and agronomical effects. The aim of this review is to deal with the category of the organic fertilizers containing Cr derived from tannery processes focusing on its chemical, productive, legislative, environmental and agronomical aspects. Special attention is given to the ambiguous issue of Cr briefly summarizing the most important studies of the last forty years
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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