1,720,959 research outputs found
Structurally controlled development of a sulfuric hypogene karst system in a fold-and-thrust belt (Majella Massif, Italy)
No full textWe documented the deformation in the southeastern domain of the Majella anticline (Central Apennines, Italy) to
highlight timing and structural characteristics of different fracture sets affecting the outcropping Cretaceous-
Miocene ramp carbonates. An isolated and inactive hypogene karst system produced by sulfuric acid (Cavallone-
Bove cave system) was studied following a multidisciplinary approach. Our findings suggest that deeprooted,
sub-vertical strike-slip fault zones reaching the H2S source rocks were the main vehicle for ascending
acidic fluid flow. Linkage and intersection of these faults by splays in extensional stepovers and pre-orogenic
normal faults permitted ascending fluids to reach multiple recharge points (feeders) near the paleo watertable.
In proximity to the oxygenated groundwater, where H2SO4 was produced, lateral dissolution focused
along bedding planes and zones of localized deformation (fracture clusters) characterizing the hinge of the
anticline. We conclude that structural position in the anticline and large-offset, vertically extended strike-slip
fault zones control the localization of efficient permeability pathways and represent first order controlling features
for fluid flow in the fold-and-thrust belt. This study provides insights into the understanding of time-space
evolution, geometry, and pattern of sulfuric hypogene karst systems in folded carbonates, whose prediction is
critical for fractured and karstified reservoirs
New mineralogical record of guano-associated phosphates in Colombo Cave (Toirano, Liguria, Italy)
Full text linkColombo Cave is part of Toirano karst system and opens at 247 m a.s.l. The wide entrance passage was used during prehistoric times, and a 4.5 m deep archaeological excavation pit is located 10 m from the entrance. The main room is dominated by a large central rock pillar and the floor is completely covered by important ancient bat guano deposits. Samples were taken in separate containers and were representative of old guano deposits and a hard-yellow crust covering the guano heap. All samples were identified by XRD and SEM-EDS analysis.
The results indicate that old guano samples were composed mainly of calcite, quartz, spheniscidite and minor amounts of xenotime (Y), monazite, zircon, and rutile. In particular, spheniscidite (NH4,K)(Fe3+,Al)2(PO4)2(OH)·2H2O forms from the reaction of ammonium-rich fresh guano leachates with probably clay sediments containing Fe and muscovite (source of K and Al) (Sauro et al., 2014). The mineral associations present in soft yellow and whitish crusts that cover guano were represented by gypsum CaSO4·2H2O, brushite Ca(HPO4)·2H2O, ardealite Ca2(HPO4)(SO4)·4H2O and newberyite Mg(HPO4)·3H2O. Brushite and ardealite occur as cryptocrystalline aggregates varying in color from white-ivory to yellow-ivory and form by the reaction of sulfuric and phosphoric acid with limestone rock (Hill & Forti, 1997; Puşcaş et al., 2014). Newberyite was less common and likely comes from the interaction of phosphates with Mg provided by the disaggregation of the dolomitic host rock. The identification of these minerals is important because they were never reported from Liguria. Further investigations will be conducted in order to understand the minerogenetic processes involved in these guano-associated minerals, and their evolution through time in the damp cave environment (Audra et al., 2019)
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
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
Pleistocene sea level changes as revealed by flank margin caves in telogenetic limestones in Sicily and Sardinia (Italy).
No full textCoastal karst areas often host many indices of past sea level changes, such as marine terraces, fossiliferous sediments,
tidal notches and coastal caves. Tectonic movements can then displace these ancient coastlines vertically. The interplay
between rising or falling sea level and uplifting or subsidence can be very complex and difficult to unravel. The combination
of a detailed knowledge of marine terraces and the study of some flank margin caves located at various altitudes have
allowed to reconstruct the speleogenetic history of the coastal plain of Cornino-Custonaci (NW Sicily). Along the centraleastern
coast of Sardinia, instead, the detailed study of the Fico Cave has allowed to recognise it as a flank margin cave
developed on five levels, related to Pleistocene sea level highstands. These studies show that this type of mixing corrosion
caves is much more widespread than previously thought also in telogenetic limestones. These caves, being excellent sea
level markers, might help coastal geomorphologists to understand more on both sea level rise and fall and tectonic
movements in coastal areas
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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