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Analisi vulcanologico-stratigrafica della Successione del Tavolato
No full textStudi stratigrafici e sedimentologici nella piana di Ciampino (Successione del Tavolato) e in
particolare di una trincea appositamente scavata presso il sito archeologico di Lucrezia Romana, hanno
confermato che dal cratere del Lago Albano sono avvenute eruzioni freatomagmatiche in epoca Olocenica e
ripetuti fenomeni che hanno generato lahar fino a quando, nel IV secolo a.C., i romani vi scavarono una
galleria di drenaggio. Le portate dei corsi d’acqua, stimate dalle caratteristiche dei principali depositi
paleofluviali, hanno dato valori elevatissimi, fino a due ordini di grandezza superiori ai regimi attuali,
probabilmente connesse a fenomeni esondativi del Lago Albano che hanno inondato la piana di Ciampino
situata a valle del punto morfologicamente più basso del cratere che ospita il lago. È possibile che questi
fenomeni esondativi siano stati causati da iniezione di fluidi caldi ricchi in CO2 sul fondo del lago, forse in
connessione con attività sismica. L’area dei Colli Albani è infatti sede di importanti emissioni di gas di
origine profonda, per le principali delle quali vengono riportati i risultati di campagne di misura del flusso
di CO2 dal suolo e la composizione chimica ed isotopica del gas emesso (Cava dei Selci, S. Maria delle Mole,
Solforata, bordi dei laghi craterici di Albano e Nemi). Per Cava dei Selci sono riportati anche i risultati di
misure in continuo, con una stazione automatica, del flusso di CO2 dal suolo che risulta sensibilmente
influenzato dall’umidità del terreno, e delle concentrazioni in aria di CO2 e H2S che superano spesso le soglie di pericolosità. Le aree di maggiore emissione di gas (Cava dei Selci e Solforata) sono ubicate su alti
strutturali del basamento carbonatico pre-vulcanico, che rappresenta una zona privilegiata per l’accumulo
dei gas che risalgono dal profondo. Una debole anomalia di emissione di gas, corrispondente ad un
lineamento strutturale NE-SW, è stata trovata anche sul bordo orientale del Lago Albano. Forti variazioni nel
tempo del flusso di CO2 sono state osservate a Cava dei Selci, probabilmente dovute sia ad attività sismica
sia a perturbazioni del regime idraulico prodotte dal forte abbassamento della falda idrica causato dal suo
eccessivo sfruttamento. L’esistenza di momenti di forte aumento dell’emissione di CO2 negli ultimi 2.000
anni, con frequenza circa centennale, è stata messa in evidenza dallo studio geocronologico, chimico e
isotopico di speleotemi presenti in una vecchia cava romana (Villa Centroni). Qui si osservano ripetute
interruzioni nell’accrescimento di stalattiti e stalagmiti attribuite a variazioni da sovrassature a sottosature in
carbonato di calcio delle acque di stillicidio, prodotte da periodici influssi di CO2. Tutti i dati convergono
quindi nell’indicare che i Colli Albani sono un vulcano quiescente, interessato fino ad epoca molto recente
da fenomeni eruttivi ed esondativi dal cratere del Lago Albano. Ripetute campagne geochimiche nel Lago
Albano (e una nel Lago di Nemi), con misure di parametri chimici e fisici lungo profili verticali e l’analisi
delle acque e dei gas in essa disciolti, indicano che il lago è sostanzialmente stabile e che la pressione totale
dei gas ad ogni profondità si è mantenuta negli ultimi sette anni lontana dalle soglie di pericolosità.Stratigraphic
and sedimentological studies of the Ciampino plain (Tavolato Succession) and particularly of an ad hoc
excavated trench near the archaeological site of Lucrezia Romana, confirm that Holocene phreatomagmatic
eruptions have occurred from Lake Albano crater, as well as repeated lahar generating phenomena until IV
Century b.C., when Romans excavated a drainage tunnel from the lake. The paleo-river flows, estimated
from the characteristics of the main fluvial deposits, were very high, orders of magnitude higher than the
present flows, and were likely produced by water overflows from Lake Albano, that inundated the
Ciampino plain located downslope from the lowest rim of the crater hosting the lake. These overflows could
have been generated by injection of hot fluids and gas in the bottom of the lake, possibly in relation with
seismic activity. The Colli Albani area actually contains several zones with high emission of deep originated
gas, for which the CO2 soil flux and the chemical and isotopic composition of the emitted gas are reported
(Cava dei Selci, S. Maria delle Mole, Solforata, rims of Albano and Nemi crater lakes). For Cava dei Selci
results are also reported of continuous measurement by an automatic station of CO2 soil flux, which is
clearly affected by soil moisture. The CO2 and H2S air concentrations, also continuously monitored,
frequently exceed their hazard thresholds. The zones with the highest gas emission (Cava dei Selci and
Solforata) are located over structural highs of the pre-volcanic carbonate basement where deep originated
fluids preferentially accumulate. A weak gas anomaly, corresponding to a NE-SW structural lineament, has
been identified on the eastern rim of Lake Albano. High temporal variations have been observed in the CO2
soil flux of Cava dei Selci, possibly due to both seismic activity and perturbation of the hydraulic regime
caused by the water table lowering as a consequence of aquifer over exploitation. The occurrence of periods
of strong increase of CO2 release over the last 2,000 years, with a nearly centennial frequency, has been
recognized through a geochronological, geochemical and isotopic study of the speleothemes present in an
old Roman quarry (Villa Centroni). Repeated interruptions are observed in the growing of stalactites and
stalagmites, that have been attributed to changes from calcium carbonate oversaturated to undersaturated of
the dripping water, in turn produced by periodic CO2 injections. All data coherently indicate that Colli
Albani are a quiescent volcano that produced eruptive and exondative phenomena from the Albano crater
lake until a very recent epoch. Repeated geochemical surveys of the Lake Albano (one also on the Lake
Nemi), with measurement of physical and chemical parameters along vertical profiles and the chemical
analyses of the water, including dissolved gases, indicate that the lake is stable and that the total gas
pressure at any depth remained in the last seven years far from the hazard threshold
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
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
A new discovery: the < 25 ka Phreatomagmatic and Phreatic activity of the Albano Maar, Colli albani volcano (Italy) and definition of the related hazard for the Roman hinterland
No full textDispelling 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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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