1,720,962 research outputs found
Physical and chemical strain-hardening during faulting in poorly lithified sandstone: The role of kinematic stress field and selective cementation
Full text linkIn this work, we report the results of a multidisciplinary study describing the structural architecture and diagenetic evolution of the Rocca di Neto extensional fault zone developed in poorly lithified sandstones of the Crotone Basin, Southern Italy. The studied fault zone has an estimated displacement of ∼90 m and consists of: (1) a low-deformation
zone with subsidiary faults and widely spaced deformation bands; (2) an ∼10-mwide damage zone, characterized by a dense network of conjugate deformation bands; (3) an ∼3-m-wide mixed zone produced by tectonic mixing of sediments with different grain size; (4) an ∼1-m-wide fault core with bedding transposed into foliation and ultracomminute black gouge layers. Microstructural investigations indicate that particulate flow was the dominant early-stage deformation mechanism, while cataclasis became predominant after porosity loss, shallow burial, and selective calcite cementation. The combination of tectonic compaction and preferential cementation led to a strain-hardening behavior inducing the formation of “inclined conjugate deformation band sets” inside the damage zone, caused by the kinematic stress field associated with fault activity. Conversely, conjugate deformation band sets with a vertical bisector formed outside the damage zone in response to the regional extensional stress field. Stable isotope
analysis helped in constraining the diagenetic environment of deformation, which is characterized by mixed marine-meteoric signature for cements hosted inside the damage zone, while it progressively becomes more meteoric moving outside the fault zone. This evidence supports the outward propagation of fault-related deformation structures in the
footwall damage zone
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
What Is the Impact of Leaky Sewers on Groundwater Contamination in Urban Semi-Confined Aquifers? A Test Study Related to Fecal Matter and Personal Care Products (PCPs)
No full textUrban areas exercise numerous and strong pressures on water bodies, implying that different external anthropogenic factors also stress groundwater. Sewerage networks play an important role, being the place of wastewater flow. When sewerage deterioration conditions occur, aquifers can be contaminated by contaminants contained within wastewater. The study aims to verify the impact of sewerage leaks in urban semi-confined aquifers through a multidisciplinary approach. Geological, hydrogeological, hydrochemical, microbiological, and biomolecular investigations are carried out in a test site close to a sewer pipe, from February to October 2022. Microbiological analyses are carried out on a monthly basis, contextually to hydraulic head measurements in purpose-drilled piezometers. The presence of sandy intercalations and the prevalence of silt within the outcropping (about 10 m thick) aquitard makes the aquifer vulnerable to percolation from leaky sewers, therefore causing persistent microbial contamination in groundwater. The presence of fecal indicators (including pathogenic genera), corrosive and human-associated bacteria markers, is detected. The magnitude of microbiological impact varies over time, depending on hydrogeological factors such as dilution, hydrodynamic dispersion, and variation of the groundwater flow pathway at the site scale. As for personal care products, only Disodium EDTA is detected in wastewater, while in groundwater the concentrations of all the analyzed substances are lower than the instrumental detection limit
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
Deformation mechanisms and slip behaviors of tectonically deformed conglomerates from the Central Apennines fold-and-thrust belt. Implications for shallow aseismic and seismic slip
Full text linkFold-and-thrust belts and accretionary prisms exhibit considerable variability in slip behaviors along active
faults. While numerous studies have investigated fault mechanics and slip behaviors in carbonate-, shale-, and
sandstone-hosted faults as well as clay-rich portions of shallow accretionary prisms, the deformation mechanisms
and slip behaviors of deformed, thrust-top molasse-type conglomerates remain poorly understood. To fill this
knowledge gap, we conducted structural and microstructural analyses on exhumed and deformed conglomerates
in the footwall of an out-of-sequence thrust from the Central Apennines fold-and-thrust belt (Italy). Our findings
aim to constrain conglomerate deformation mechanisms and infer possible slip behaviors. We observed flattened
pebbles and an intense foliation comprising densely spaced, thrust-parallel, clay-rich stylolites that indicate slow
deformation attributed to carbonate dissolution during aseismic creep. In contrast, quartz clasts with calcite
micro veins and micrometer-thick slip increments in slickenfibers suggest fast brittle failure and fluid overpressure
in competent pebbles, while the matrix continues to deform aseismically through pressure solution. The
general structure is similar to block-in-matrix textures observed in tectonic m ́elanges from exhumed subduction
zones and accretionary prisms. Our results provide new insights into the slip behaviors of shallow (<~1 km)
portions of fold-and-thrust belts, complementing existing understandings of deformation mechanisms and slip
behaviors across different depth ranges in fold-and-thrust belts and accretionary prisms
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
- …
