1,721,656 research outputs found
La decorazione pubblica in Italia tra l'Unità e la prima guerra mondiale
Get PDFLa tesi di dottorato si propone di indagare la decorazione pittorica pubblica tra l’unificazione storica italiana e la prima guerra mondiale attraverso la disamina di analogie e differenze fra i diversi programmi decorativi, le modalità di svolgimento dei concorsi, i giudizi della critica coeva e le reazioni del pubblico.
Il fine della tesi è catalogare i casi più rappresentativi, selezionati sia per la loro specificità e unicità, sia per la loro tendenza a emergere come modello di riferimento in un contesto locale o nazionale, nonché individuare tematiche, procedure, affinità e differenze nella decorazione pubblica fra gli estremi cronologici presi in considerazione.
La tesi si concentra su argomenti quasi del tutto ignorati dalla critica d'arte: il periodo preso in esame, ad esempio, è stato sempre trascurato dalla storiografia artistica a differenza del ventennio fascista, i cui programmi decorativi, le dinamiche concorsuali e la ricezione da parte del pubblico e della critica sono stati attentamente vagliati e analizzati. Si è cercato, inoltre, in assenza di una trattazione sistematica dell’argomento, di acquisire una visione d'insieme sul tema, verificando l’esistenza di elementi comuni ricorrenti e cogliendo i mutamenti registrabili nell'ambito della nuova produzione figurativa.
L'argomento è affrontato secondo molteplici piste d'indagine. Alla base vi è stato uno spoglio sistematico dei cicli decorativi suddiviso per zone geografiche, privilegiando i centri principali degli stati preunitari e città come Torino e Firenze che furono le prime capitali del neonato regno italiano.
Le informazioni sono state reperite attraverso la disamina di molteplici strumenti bibliografici. Di particolare importanza si sono rivelati opuscoli contemporanei, utili per decifrare i programmi iconografici. Altrettanto utili si sono rivelate le fonti della letteratura coeva, come riviste (fra cui «L’illustrazione italiana» o «Natura ed arte») e quotidiani nazionali e locali, fondamentali per comprendere il contesto, la committenza e la ricezione da parte del pubblico del tempo nonché l’esistenza di un dibattito critico tra gli intellettuali dell’epoca. Altre informazioni significative, che in alcuni casi hanno chiarito la genesi dei programmi iconografici, sono stati rinvenute nei documenti conservati presso i molti archivi statali, provinciali e comunali delle città ove queste decorazioni furono eseguite
Shake-down spectroscopy as state- and site-specific probe of ultrafast chemical dynamics
No full textTracking the multifarious ultrafast electronic and structural changes occurring in a molecule during a photochemical transformation is a challenging endeavor that benefits from recent experimental and computational progress in time-resolved techniques. Measurements of valence electronic states, which provide a global picture of the bonding structure of the molecule, and core electronic states, which provide insight into the local environment, traditionally require different approaches and are often studied separately. Here, we demonstrate that X-ray pulses from a seeded free-electron laser (FEL) enable the measurement of high-resolution, time-resolved X-ray photoelectron spectra (XPS) that capture weak satellite states resulting from shake-down processes in a valence-excited molecule. This approach effectively combines the advantages of both valence- and core-state investigations. We applied this method to investigate photoexcited CS
2molecules, where the role of internal conversion (IC) and intersystem crossing (ISC) in determining the predissociation dynamics is controversial. We present XPS spectra from photoexcited CS
2, obtained at the FERMI FEL. High-resolution measurements, compared to the corresponding spectra obtained from accurate multireference quantum chemical calculations, reveal that shake-down satellite channels are highly sensitive to both valence electronic and geometric changes. Previous studies of the predissociation dynamics have led to uncertain assignments of the branching between singlet and triplet excited states. We derive a propensity rule that demonstrates the spin-selectivity of the shake-downs. This selectivity allows us to unequivocally assign contributions from the bright and dark singlet excited states, with populations tracked along the predissociation dynamic pathway.</p
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
Modelling analysis of low platinum polymer fuel cell degradation under voltage cycling: Gradient catalyst layers with improved durability
No full textImproving the durability of polymer electrolyte membrane fuel cells with low platinum loading is a crucial step in the development of next generation electric vehicles. In this work a simplified model of nanoparticle growth is spatially solved across the catalyst layer and combined with a PEMFC model to analyze the heterogeneity of degradation that is induced by accelerated stress test for electrocatalyst durability, which mimics the degradation due to load cycling. The model is calibrated and later validated by analyzing experimental data collected on cathode catalyst layers with 0.1 mg cm(-2) platinum loading and average particle size ranging from 2 nm to 5 nm. Non-uniform degradation is observed in the catalyst layer consequently to the formation of a platinum depleted region next to the membrane, which, according to the model, results from diffusion and precipitation of dissolved platinum into the membrane. Performance of catalyst layers with gradient structure is simulated to get insight into the degradation of non-uniform catalyst layers and results are compared to experimental data. It is concluded that gradient catalyst layers mitigate performance degradation because evolve towards more uniform distribution of active surface and improve transport loss due to low-roughness factor and Ohm loss in the catalyst layer
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
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
Time-resolved vacuum-ultraviolet photoelectron spectroscopy of the Ã1Au state of acetylene
No full textUltrafast time-resolved photoelectron spectra are reported for the vacuum-ultraviolet (VUV) photoionization of acetylene following excitation to the Ã1Au state via UV absorption at 200 nm. The excitation energy lies above the lowest dissociation threshold to C2H X̃2Σ+ + H, as well as above the threshold for adiabatic dissociation of the Ã1Au state to form C2H (Ã2Π) + H. The time-dependent mass spectra and photoelectron spectra provide insight into the intramolecular decay processes of the Ã1Au state. In addition, photoelectron spectra of the Ã1Au state with VUV light access both the X̃2Πu and Ã2Σg+ states of the ion, as well as the predicted, but previously unobserved, 1 2Πg state, which corresponds to a two-hole, one-particle configuration that lies in close proximity to the Ã2Σg+ state. The 1 2Πg state is split into 2A2 + 2B2 and 2Ag + 2Bg states in the cis and trans configurations, respectively. Electronic structure calculations, along with trajectory calculations, reproduce the principal features of the experimental data and confirm the assignment of the 1 2Πg state
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