1,543 research outputs found
Two-time autocorrelation function in phase-ordering kinetics from local scale-invariance
The time-dependent scaling of the two-time autocorrelation function of spin
systems without disorder undergoing phase-ordering kinetics is considered. Its
form is shown to be determined by an extension of dynamical scaling to a local
scale-invariance which turns out to be a new version of conformal invariance.
The predicted autocorrelator is in agreement with Monte-Carlo data on the
autocorrelation function of the 2D kinetic Ising model with Glauber dynamics
quenched to a temperature below criticality.Comment: Latex2e, 7 pages with 2 figures, with epl macro, final from, to
appear in EP
Shadowing e Gis qualitativo: due strumenti per narrare la cittĂ
Questo breve articolo descrive la città attraverso due tecniche di ricerca qualitativa (lo shadowing e il Gis qualitativo). Partendo da alcuni esempi, tratti dall’esperienza sul campo, vengono valutati limiti e possibilità delle tecniche in oggetto. L’obiettivo è quello di argomentare la necessità di utilizzare e sviluppare nuovi strumenti metodologici per conoscere le configurazioni urbane. Gli autori sostengono il bisogno di muoversi all’interno di un orizzonte interdisciplinare e di utilizzare tecniche capaci di far emergere narrazioni polifoniche della città . Analizzando le potenzialità dialogiche dello shadowing e le potenzialità sovversive dei Gis qualitativi, una cartografia capace di rappresentare lo spazio mentale degli abitanti, viene affermata la necessità di continuare nella pratica di metodi ibridi, capaci di stimolare la creazione di nuove ri-descrizioni. La città , quindi, per essere compresa, pensata e trasformata ha bisogno di creatività e sperimentazione: nuovi strumenti che tentino modalità ibride di conoscenza, scardinando l’egemonia di rappresentazioni autoritarie incapaci di dare corpo e voce ai gruppi sociali meno potenti. L’obiettivo finale, dunque, diviene il bisogno di proiettare la ricerca urbana qualitativa in un orizzonte politico, inteso come spazio pubblico della discussione e dell’interazione.This brief paper describes the city through the use of two different techniques of qualitative research: shadowing and qualitative Gis. By discussing a few examples of field research, the paper assesses the limits and possibilities of these techniques. The aim is to prove the necessity of using and developing new methodologies to investigate the most recent urban phenomena. In order to achieve this goal, only an interdisciplinary approach can help the emergence of polyphonic narrations of the city. Through the analysis of the dialogic assets that shadowing possesses, and of the subversive potential of qualitative Gis (conceived as a sort of mapping that can represent the mind-space of citizens), the authors succor the use of mixed methodologies that enhance the creation of narrative re-descriptions of the urban forms. Understanding, conceiving and transforming the city implies creativity and experimentation: therefore, we need to conceive new instruments that use hybrid knowledge systems, and shatter the hegemony of those traditional, authoritative representations that cannot give voice to the most deprived social groups. The final goal of the paper is thus defined as the need to project qualitative urban research into a political horizon that becomes the public space of discussion and interaction
Application of HR-NMR for the Metabolic Kinetic Assessment of Red Mullet (Mullus barbatus) and Bogue (Boops boops) Samples during Different Temperature Storage
: Fish freshness and quality can be measured through several indices that can be both chemical and physical. The storage temperature and the time that elapses following the catching of the fish are fundamental parameters that define and influence both the degree of freshness and nutritional quality. Moreover, they particularly effect the kind of fish we considered. In this research, it was observed how different temperatures of storage and shelf-life (+4 °C and 0 °C) may affect the metabolic profile of red mullet (Mullus barbatus) and bogue (Boops boops) fish samples over time, specifically observing the alteration of freshness and quality. In particular, a High-Resolution Nuclear Magnetic Resonance (HR-NMR)-based metabolomics approach was applied to study the metabolic profile changes that occur in fish spoilage. The HR-NMR spectroscopy data were useful for calculating a kinetic model that was able to predict the evolution of different compounds related to fish freshness, such as trimethylamine (TMA-N) and adenosine-5'-triphosphate (ATP) catabolites for the K-index. Furthermore, NMR in combination with chemometrics allowed us to estimate a further kinetic model able to represent the spoilage evolution by considering the entire metabolome. In this way, it was also possible to detect further biomarkers characterizing the freshness and quality status of both red mullets and bogues
Validation of a 1H-NMR Spectroscopy Quantitative Method to Quantify Trimethylamine Content and K -Index Value in Different Species of Fish
The chemical analysis that is frequently employed for the evaluation of the freshness of fish includes (i) the quantification of trimethylamine (TMA) and (ii) the estimation of the K-Index, based on the ratio between the concentrations of adenosine triphosphate (ATP) and its breakdown products. TMA is quantified using a colorimetric reference method (AOAC), while the K-Index is usually determined by HPLC. The present work proposes a method for the above freshness biomarkers based on HR H-1-NMR as an alternative method able to assess both indexes simultaneously on aqueous fish extracts. To validate the proposed H-1-NMR method, a large set of validation checks has been addressed, such as accuracy, precision, specificity, limits of detection, linearity, and range of linearity and quantification according to EuroChem guidelines. The results show that the methodology satisfies all the validation requirements at the same level as the most frequently used methods, with the advantage of being faster and more repeatable, avoiding the use of solvents, such as toluene and formaldehyde, or dangerous reagents such as picric acid
From “Strategic Fit” to Synergy Evaluation in M&A Deals
The aim of this paper is to grasp the processes underlying the genesis and assessment of synergies in M&A deals. We proceed to an in-depth scrutiny of the foundations of synergies using Porter’s model of the value chain. A discernment of the nature of synergies and the mode of their emergence is helpful to clarify to what extent and under which boundary conditions it is appropriate to apply the DCF or the real option techniques for evaluating each type of synergy. Combining both financial tools, the methodology suggested for evaluating the synergies is able to: evaluate projects of M&As, orient the selection of target firms and the definition of the premium of acquisition, and drive the integration processes
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