1,721,003 research outputs found
Architecture after Revolution
No full textThe work presented in this book is an invitation to undertake an urgent architectural and political thought experiment: to rethink today’s struggles for justice and equality not only from the historical perspective of revolution, but also from that of a continued struggle for decolonization; consequently, to rethink the problem of political subjectivity not from the point of view of a Western conception of a liberal citizen but rather from that of the displaced and extraterritorial refugee. You will not find here descriptions of popular uprising, armed resistance, or political negotiations, despite these of course forming an integral and necessary part of any radical political transformation. Instead, the authors present a series of provocative projects that try to imagine “the morning after revolution.”
Located on the edge of the desert in the town of Beit Sahour in Palestine, the architectural collective Decolonizing Architecture Art Residency (DAAR) has since 2007 combined discourse, spatial intervention, collective learning, public meetings, and legal challenges to open an arena for speculating about the seemingly impossible: the actual transformation of Israel’s physical structures of domination. Against an architectural history of decolonization that sought to reuse colonial architecture for the same purpose for which it was originally built, DAAR sees opportunities in a set of playful propositions for the subversion, reuse, profanation, and recycling of these structures of domination and the legal infrastructures that sustain them.
DAAR’s projects should be understood as a series of architectural fables set in different locations: an abandoned military base near Beit Sahour, the refugee camp of Dheisheh in Bethlehem, the remnants of three houses on the Jaffa beach, the uncompleted Palestinian Parliament building, the historical village of Battir, the village of Miska destroyed during the Nakba, and the red-roofed West Bank colony of Jabel Tawil (P’sagot) next to Ramallah-El Bireh.
Design by Surfac
Rocks’ Rheology and Seismic Attenuation: What do we know?
No full textRheological properties of the rocks, depending on various parameters (grain size,
composition, hydrous conditions), determine their deformation mode in response to the tectonic
stress. At shallow depths, the rocks show a pressure-dependent frictional (brittle) behavior, which
turns in a viscous (ductile creep) behavior, as temperature increases (e.g., Jacquey and Cacace 2021).
The brittle-ductile transition (BDT) occurs at depths where the shear stress, driving the two
deformation modes, are equal for some given strain rate, composition, stress regime, and thermal
gradient. Such a transition marks the maximum depth of the intraplate earthquakes and of fluids
circulation in porous media.
Seismological datasets accounts for real media properties, providing wave propagational
attributes (e.g., seismic wave velocities and attenuation) that can be exploited to add constraints to
the BDT depth. Seismic wave attenuation can be used as a potential attribute for subsurface
characterization. Indeed, its inverse, the seismic quality factor (Q), depends on the seismic frequency,
as well as on temperature, water content, and grain size of the rocks (e.g., Karato & Spetzler, 1990;
Jackson & Faul, 2010). Therefore, it is likely that seismic attenuation and the viscous modes of
deformations of rocks can be correlated, based on their dependency on the aforementioned conditions,
as expressed by an Arrhenius-type equation (Farina et al., 2019).
In this study, we investigate the quantitative relationships between seismic attenuation and
viscous rocks' rheology, especially across the domain where rocks transition from a dominant brittle
to a more ductile deformation mode. We rely on a Burgers mechanical model to derive shear wave
attenuation (1/Qs
), for several dry and wet crustal rheology, thermal conditions, and different strain
rates values. This allows us to establish geothermal and mechanical conditions at which the BDT
occurs and to cross-correlate this transition to computed shear seismic wave attenuation values. In
particular, we observe a relatively significant Qs
reduction for strain rates of 10-13 s
-1
, despite the
assumed rock‘s rheology and thermal conditions. These first results confirm our hypothesis that
variations in the Qs
factor can be effectively used to identify the BDT’s depths in tectonically active
areas. Ongoing and future works will focus on a further validation of the modelling implications by
systematic analyses of observations derived from rocks’ laboratory experiments
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
The Buntsandstein of Sardinia (Italy) as keypoint of the Western Tethys paleogeography
No full textSardinia played a key role during the opening of the Western Tethys in late Early-early Middle Triassic times, being located at the intersection of several main paleogeographic plates, and its Buntsandstein successions represent a revealing paleogeographic and sedimentary touchstone. Historical and unedited sedimentological data, detailed petrographic studies, and a review of the palynological assemblages evidence that the various formations of the Sardinian Buntsandstein Group differ noticeably from each other and were deposited in different alluvial to transitional environments related to “Alpine” rifting basins. Moreover, strong compositional differences from NS to EW in the island are also observed. They support a morphotectonic rise separating the diverse depositional basins, possibly related to main European ridges in progressive dismantling. The dominating environmental and/or (micro)climate conditions were different in the various areas, and the sedimentary basins evolved independently and diachronous through time. Moreover, the source areas for the sediments varied from articulated to gentle in morphology and substrate composition. The various stratigraphic units of the Sardinian Buntsandstein cover in the center of the island a progressively more altered, smoothed Variscan basement, locally perhaps mobilized by the incoming extensional early Alpine tectonics.
The paleoenvironmental reconstructions evidence an articulated, rough landscape, close to active structural lines, behind the depositional area of the SW Riu Is Corras Formation. A more elaborated depositional environment gave origin to the SW Punta S’Arridelli and NW Verrucano Sardo formations, whereas a flat, gentle landscape crossed by alluvial channels was located behind the mudflat of the Central Sardinia Escalaplano Formation. These diverse environments could be related to a gradual transgression over the hardrock and a progressive smoothing in time of the Sardinian Variscan basement. The petrographic study reveals the presence of sandstone and carbonate grains of unknown affinity in every Buntsandstein formational unit, possibly related to a dismantled sedimentary cycle. The palynoassemblages support a late Anisian or Pelsonian-Illyrian for the transgression of the Muschelkalk Sea on the Buntsandstein facies, whereas the bottom of the various formations cannot be dated due to a substantial unconformity. The oldest Triassic palynological assemblages identified in the succession are dated to the Aegean. They do, however, not correspond to the base of the Buntsandstein succession. In general, the palynological assemblages support a rather arid climate during the early Middle Triassic, although locally some more humid conditions are observed.
A comparison with nearby coeval plates of the western, subequatorial area of the Tethys (Western Alps, Corse, Provence) evidences the area’s key role during the opening of the “Alpine” rifting basins
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
The Upper Pennsylvanian to Middle Triassic continental succession in SW Sardinia: new key sections, stratigraphic-sedimentological refinements, and petro-sedimentary notes
No full textStratigraphical-sedimentological investgations of new and old outcrops allowed to better reconstruct the post-Variscan Upper Pennsylvanian to Middle Triassic succession in SW Sardinia. It starts with the Upper Pennsylvanian limnic San Giorgio Fm (Lower Rotliegend), formed by alternations of coarse- to mediumgrained siliciclastics. Intercalations of carbonates and volcanic rocks are present. The unit deposed in a narrow warm-wet alluvial-to-lacustrine collapse basin. The Early – Middle (?) Permian red bed Guardia Pisano Fm (Upper Rotliegend) follows: pelites, sandstones, and rare conglomerates are represented. Volcanic rocks are rare. The unit was deposed in a warm-arid alluvial environment of mid-to low-energy. The Guardia Pisano Fm is followed by the red bed Upper Permian – Lower Triassic red bed Rio Is Corras Fm (Sardinian Buntsandstein Group?). It is formed by conglomerates and calcretes with rare sandstones, pelites, and evaporites. This unit deposed in a warm(hot?)-arid fan-delta to lake environment of variable energy. Stratigraphic type-sections have been described for all the mentioned units. Scattered red beds of the Guardia Pisano Fm or the Rio Is Corras Fm are often unconformably posed over the Variscan Cambrian carbonates reliefs. Examples are known in all the SW Sardinia. At Guardia Pisano the limnic fine deposits of the upper San Giorgio Fm are covered through a weak unconformity by the Guardia Pisano Fm red beds pointing to a smooth climatic and environmental transition. The new outcrops found in the S.Giorgio basin area (Iglesias) represent the missing link between the formerly described stratigraphic units. Here the Rio Is Corras Fm conglomerates are conformably posed over red bed alternations of pelites, sandstones, conglomerates, carbonates, and evaporites representing the upper prosecution of the Guardia Pisano Fm: they mark a gradual passage from a low-energy playa to a fan delta lake environment. Preliminary petrographic analysis of the S. Giorgio sandstones classify them as litharenites and sublitharenites. Calclithites have been found. The Guardia Pisano sandstones are litharenites and minor subarkoses. The Rio Is Corras Fm rare sandstones are all calclithites. Compositional and textural maturity trends in times suggest repeated cycles of reworking of the landscape under a (warm-hot?) wet to dry climate. The almost undisturbed superposition of the various units on each other, the growing areal extent in times of the outcropping units area from the Rio S. Giorgio Fm to the Rio Is Corras Fm, the unconformable setting of the younger units also on the basement with the growing distance to the hypothesized main depocenter (S. Giorgio area?), suggest a progressive widening of this depositional continental basin in times, starting as a narrow basin in Late Pennsylvanian times and merging in the end with the wider extensional basins related to the W-Tethys rifting. Subsurface data by drills suggest at least 350 m of thickness
- …
