1,721,105 research outputs found
Stable isotope ratio analysis for the traceability of raw and cured meat
Full text linkThe effect of different factors on the stable isotope ratio (SIR) variability of the most important bioelements (2H/1H, 13C/12C, 15N/14N, 18O/16O, 34S/32S), measured using IRMS (Isotopic Ratio Mass Spectrometry), was evaluated in different types of tissues, including pig and ovine muscles, muscle lipids and lipid fractions.
To evaluate the effect of tissue turnover on the different isotope ratios, in a diet-switch experiment, 28 lambs were switched to an isotopically distinct diet and raised on two different energy allowances (high energy allowance (HEA) with a target weight gain of 150 g/day or low energy allowance (LEA) with a target weight gain of 50 g/day).
Determination of multiple stable isotope ratios (δ2H, δ13C, δ18O and δ34S) in ovine muscle indicated diet-muscle fractionations prior to the diet-switch to be -44.0‰ +1.9‰ and 0‰ for H. C and S respectively. The muscle sampled from animals on the HEA recorded higher δ13C values than muscle from animals on the LEA (p = 0.0003). The δ18O values in ovine muscle were largely influenced by the water ingested while most of the H used to build ovine muscle tissue depend on the feed rather than the drinking water. The discrimination between intra muscular lipid and diet was estimated to be -172.7, -1.3‰ and -11.5‰ for H, C and O respectively. The C half-lives of muscle were determined to be 75.7 and 91.6 days for animals receiving the high and low EA respectively and it is comparable with S half-lives measured in ovine LD. However, the estimated half-lives of lipids were too long to be used for tracking short term dietary changes in lambs and probably also in other meat animals.
In a second experiment the stable isotope ratios of bioelements in defatted dry matter and marbling and subcutaneous fat fractions were assessed in 86 ham samples belonging to six different types, with the aim of ascertaining the effect of origin and the production system on 11 isotopic ratios. The ham types were obtained from pigs reared in three regions, examining one different production factor in every location, at two levels of expression: pig genotype (local breed vs. industrial hybrid) in Friuli (Italy), pig feeding regime (Bellota vs. Campo) in Extremadura (Spain) and ham seasoning time (mid vs. end) in Emilia (Italy). The isotopic composition of meteoric water and the dietary abundance of C4 plants made it possible to distinguish Italian PDO from Spanish hams. Higher δ15N values in local breeds than in industrial hybrids might indicate relatively more nitrogen excretion, due to a higher ratio between protein degradation and protein synthesis.
The Strecker degradation of sulfur amino acids taking place during seasoning and generating dimethyl disulfide and other similar volatile compounds can explane δ34S isotopic fractionation showed to compare the End-seasoned Italian hams vs mid-seasoned ones.
The contrasting treatments within the regional batches generated promising differences in SIR, potentially useful for tracing the whole ham production system, including the processing procedure.
In a third experiment the stable isotope ratios of five bio-elements - H, O, C, N and S - were analysed in the protein and fat muscle fractions of sixty beef carcasses from zebu cattle reared in an tropical African country (Cameroon) with the scope of evaluating the effect of this specific origin on the different isotopic ratios. Zebu beef from Cameroon was shown to have a specific isotope profile, characterised by lower δ13C, δ2H and δ18O values than those reported for other areas around the world, as a consequence of the almost exclusive use of tropical C4 pasture grass for cattle feed and the geographic and climatic gradient in the isotope composition of precipitation. The isotopic composition of the fat fraction of muscle, and in particular the δ2H and δ13C values of fat, was significantly affected by the subcutaneous fat colour. The zebu with a white subcutaneous fat (“white type”) showed a clear tendency to be more enriched in 2H isotopes and more depleted in 13C isotopes than the “yellow type” , while the “cream type” presented an intermediate condition. These trends are correlated with fat composition. Within the Cameroon, multi-element analysis gave promising results for tracing the regional origin of beef and some aspects of the cattle breeding system, such as the nutritional status of animals.
On the basis of the results of this study all of the considering factors can have effect on the different isotope ratios but with different weight. Origin and type of diet outweigh turnover and technical process of products, even if they must be carefully considered to prevent possible mistake during the results evaluation
Per un'epistemologia dei nudge: dall'evidenza alla causalità
No full textThis article investigates the foundation of the concept of nudge from the perspective of the new mechanical philosophy. The research program on nudges has always underappreciated the role of mechanistic explanation, favoring an evidence-based approach. We propose a taxonomy for the different objectives of a mechanistic explanation of nudges with three main categories: stability, legitimacy, and development. Then, capitalizing on this epistemological framework, we analyze the theory of nudge as affordance (Motterlini, Perini, 2020b). This theory provides an explanation of the efficacy of nudges by postulating the involvement of the parieto-frontal network responsible for affordance perception. Here we expose the main epistemic advantages of this model, consisting mainly in its contribution to the ethics of nudging and its heuristic potential for the development of new research hypotheses and real-world application
Vibration response of in-vacuo tuneable structured fabrics
No full textThis paper presents a first survey on the vibration response of beam-like specimens formed by a vacuum plastic bag with
single-layer or double-layer 3D-printed structured fabrics encompassing spherical-octahedra, octahedra and cubes trusslike
rigid elements. The study reports a comprehensive analysis of the bending stiffness and energy dissipation properties
with respect to the level of vacuum as well as the type and number (single or double) of overlapped fabrics. In this context, it
first presents a quasi-static analysis of the bending stiffness and energy dissipation of the specimens. Then, it provides
a comprehensive overview of the specimens dynamic properties with respect to measurements of the dynamic stiffness
frequency response function and with reference to measurements of hysteresis loops at three characteristic frequencies,
namely below, at and above the fundamental bending resonance frequency of the beam-like specimens. The study shows
that the bending stiffness and thus the fundamental bending resonance frequency of the specimens can be suitably varied by
increasing the level of vacuum in the bags. The specimens made with cubic mails show the highest bending stiffness and
fundamental resonance frequency. Also, the specimens with double layer mails show much higher bending stiffness and
fundamental resonance frequency. The level of vacuum has little effect on the energy loss, which, in general, is characterised
by rather low loss factors. This suggests that once the fabric jams, there is little friction between the particles and the
principal damping mechanism is offered by the material energy dissipation in the unit particles
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
Tracing lamb meat with stable isotope ratio analysis: a review
No full textThe analysis of stable isotopes applied to the lamb meat matrix is recognized as a technique of choice not only for geographical traceability but also for verifying the correspondence between the diet provided and the prescribed one. Indeed, a large amount of information is stored in animal tissues in terms of stable isotopes relative abundances of different elements. The purpose of this review is to critically analyze all the studies carried out on lambs, focusing in particular on the isotope ratios of carbon, nitrogen, sulfur, hydrogen and oxygen of different matrices, trying to define the different ranges of variability based on the origin and diet of the lambs. Carbon is certainly the most useful for identifying the animal diet while oxygen and hydrogen confirm their ability to geographically discriminate lambs. Overall, the results of statistical models validating isotope traceability systems can reach and exceed 90% of accurac
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
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