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Stratigrafia e facies al limite Permiano-Triassico nelle Dolomiti occidentali (Provincia di Bolzano, Italia): una revisione.
No full textVengono presentati in questo lavoro i risultati dell’analisi stratigrafica e delle microfacies di un intervallo
che contiene il limite Permiano-Triassico (P-T), in quattro sezioni stratigrafiche ubicate nelle Dolomiti occidentali
(Masi Saracini, Sass de Putia W, Seres e Bulla), già oggetto di numerosi studi negli ultimi 30 anni.
Abbiamo controllato la posizione e la qualità dei dati di campagna, originali o tratti dalla letteratura, e li abbiamo
ottimizzati in modo da evitare sia la sovrapposizione di informazioni, sia la loro ripetizione artificiale
nel record stratigrafico. Abbiamo esaminato al microscopio e interpretato le microbiofacies che compaiono nei
tre cicli trasgressivi-regressivi (C1,...,C3), ciascuno dei quali è spesso da circa 1 m ad alcune decine di metri,
che compongono la successione. Le microbiofacies basali e di tetto di ciascun ciclo sono caratteristiche rispettivamente
delle veloci fasi trasgressive e regressive; queste ultime sono visibili solo in alcuni siti, ove furono
preservate dall’erosione subaerea e da quella connessa con il processo trasgressivo (ravinement) successivi. Le
microbiofacies della parte mediana dei cicli sono invece meno diagnostiche, in quanto i diversi componenti
(alghe calcaree, gasteropodi, micro- e macroforaminiferi, crinoidi e bivalvi) risultano quasi ovunque fortemente
mescolati. La causa risiede, almeno per il tratto sommitale della Formazione a Bellerophon (i.e. Membro di
Bulla) nell’elevata energia delle correnti di tempesta che spazzavano il fondale, profondo alcuni metri, del
settore nord-occidentale del Bellerophon Gulf. Un aiuto per l’interpretazione paleogeografica è fornito dalla
distribuzione spaziale dei grandi brachiopodi (Comelicania sp.) la cui presenza, poco-nulla rimaneggiata, indica
le aree di altofondo, ricche di nutrimento.
Il limite fra la Formazione a Bellerophon e la sovrastante Formazione di Werfen è caratterizzato da una
breve e intensa fase regressiva (shallowing), che segna l’inizio del più forte evento di scomparsa-estinzione
(ME3) nella paleo-Tetide occidentale. Il fortissimo impoverimento dei taxa a scheletro calcareo caratterizza
l’accumulo trasgressivo basale (ravinement) della Formazione di Werfen, e si accompagna con la comparsa di
microbialiti e stromatoliti anche domiformi e delle ooliti. Queste ultime divengono via via più grandi e meglio
formate verso l’alto, ad indicare la stabilizzazione almeno momentanea dell’ambiente marino. L’importante
evento biologico di estinzione ME3 derivò da un rapido e complesso cambiamento climatico (più caldo e arido),
che sconvolse gli habitat marini di bassa profondità e le aree continentali intorno alla paleo-Tetide occidentale. In questo caso, infatti, la distribuzione latero-verticale
dei sedimenti e delle microbiofacies segue logiche biologiche
e meccaniche quasi-casuali, secondo modelli illustrati
recentemente in ambienti attuali di piana tidale
bahamiana. La prima apparizione evolutiva del conodonte
Hindeodus parvus avviene in questo contesto paleogeografico stressato, poco più di 1 m sopra ME3. Per
finire, le quattro mappe paleogeografiche presentate in
questo lavoro, pur se riferite a brevi periodi di tempo
(migliaia-decine di migliaia di anni) in corrispondenza
di eventi circa isocroni (limiti di cicli o di parasequenze
deposizionali) e corroborati da dati biostratigrafici certi,
hanno un carattere schematico
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
Impact of active rock glaciers on solute chemistry in Alpine headwaters
Get PDFMountain permafrost is abundant in the European Alps where mean annual air temperature (MAAT) is below -3°C, but there are also sites with MAAT around -1°C. Studies based on borehole soundings have revealed a warming of mountain permafrost of up to 1°C during recent decades. An important form of mountain permafrost in the European Alps are active rock glaciers, lobate- or tongue-shaped bodies of unconsolidated rocks and debris with an ice core or ice-matrix structure, which makes active rock glaciers sensitive indicators of climate change. There is evidence that the increase in air temperature has recently favored the solute release from active rock glaciers, and pronounced changes in water quality of headwaters in the Alps have been described (Thies et al. 2007, 2013).
Here, we report on the seasonality of solute concentrations in selected rock glacier streams in the Central Eastern Alps (Austria, Italy). Bedrock at the sites consists of paragneiss and micaschist of the Oetztal metamorphic complex. Only negligible anthropogenic impacts were observed at the selected sites (e.g. minor summer grazing of cattle). Substance concentrations of most streams revealed a strong increase up to a factor of 5 through the summer season, and thus reflected the seasonally varying contributions of the melting winter snow pack, summer precipitation, groundwater and ice melt to the discharge of active rock glaciers. Dominating ion species were sulfate, calcium and magnesium, which comprised about 98% of the total ion load. High concentrations of metals like aluminum, nickel or manganese were found in acidic streams at pH values of 4.4 to 5.2. Reference streams without any impact of active rock glaciers, on the contrary, revealed no seasonality in solute concentrations and values remained one to two orders of magnitude below those of rock glacier streams. We show vertical solute profiles in the ice of a 40 m long core drilled at an active rock glacier in the Italian Alps, where distinct layers of extremely high ion and metal concentrations were detected and peak values of electrical conductivity exceeded 1000 ìS/c
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
Detecting Recent Dynamics in Large-Scale Landslides via the Digital Image Correlation of Airborne Optic and LiDAR Datasets: Test Sites in South Tyrol (Italy)
Get PDFLarge-scale slow-moving deep-seated landslides are complex and potentially highly damaging phenomena. The detection of their dynamics in terms of displacement rate distribution is therefore a key point to achieve a better understanding of their behavior and support risk management. Due to their large dimensions, ranging from 1.5 to almost 4 km(2), in situ monitoring is generally integrated using satellite and airborne remote sensing techniques. In the framework of the EFRE-FESR SoLoMon project, three test-sites located in the Autonomous Province of Bolzano (Italy) were selected for testing the possibility of retrieving significant slope displacement data from the analysis of multi-temporal airborne optic and light detection and ranging (LiDAR) surveys with digital image correlation (DIC) algorithms such as normalized cross-correlation (NCC) and phase correlation (PC). The test-sites were selected for a number of reasons: they are relevant in terms of hazard and risk; they are representative of different type of slope movements (earth-slides, deep seated gravitational slope Deformation and rockslides), and different rates of displacement (from few cm/years to some m/years); and they have been mapped and monitored with ground-based systems for many years (DIC results can be validated both qualitatively and quantitatively). Specifically, NCC and PC algorithms were applied to high-resolution (5 to 25 cm/px) airborne optic and LiDAR-derived datasets (such as hillshade and slope maps computed from digital terrain models) acquired during the 2019-2021 period. Qualitative and quantitative validation was performed based on periodic GNSS surveys as well as on manual homologous point tracking. The displacement maps highlight that both DIC algorithms succeed in identifying and quantifying slope movements of multi-pixel magnitude in non-densely vegetated areas, while they struggle to quantify displacement patterns in areas characterized by movements of sub-pixel magnitude, especially if densely vegetated. Nonetheless, in all three landslides, they proved to be able to differentiate stable and active parts at the slope scale, thus representing a useful integration of punctual ground-based monitoring systems
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
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