5,494 research outputs found
Quantiles for Fractions and Other Mixed Data
This paper studies the estimation of quantile regression for fractional data, focusing on the case where there are mass-points at zero or/and one. More generally, we propose a simple strategy for the estimation of the conditional quantiles of data from mixed distributions, which combines standard results on the estimation of censored and Box-Cox quantile regressions. The implementation of the proposed method is illustrated using a well-known dataset.
Transcurrent continental tectonics model
The Ossa-Morena Zone (SW Iberian Massif)
was affected by continuous orogen-parallel transcurrent
continental tectonics from the Neoproterozoic to the
Carboniferous times, involving transtension (TT) and
transpression (TP) processes that co-existed together,
occurred separately in neighbouring regions by the means
of strain partitioning or even worked diachronically. A
first stage of transpression TP1 took place during the Late
Neoproterozoic–Lower Cambrian as a result of Cadomian
arc-continent collisional processes. Structures generated
by transtension TT1 from Cambrian to Lower Devonian
were related to strong lithosphere stretching responsible
for the development of basins controlled by major detachments,
tilting, rifting and important tectono–thermal
diachronic processes. Denudation phenomena and inhibition
of sedimentation related with thermal uplift
(asthenosphere upwelling) and consequent subsidence
caused by isostatic equilibrium, involving generalized
transgressions, were processes responsible for major unconformities.
The Variscan TP2-TT2 episodes that followed
diachronically TP1-TT1, by maintaining the orogen-
parallel transport direction, were concomitant with
syntectonic deposition of continental basins in the OMZ
and foreland basins in the SPZ. TT2 local transtension
and tectonic exhumation of deep crustal rocks along
major shear zones, favoured the opening of tectonic
troughs filled up by sediments and volcanism. TP2
shortening have generated fold axes parallel to the orogen-
strike and composite dissymmetric flower structures
A new model for the Hercynian Orogen of Gondwanan France
The study by Shelley and BossieÁre (2000) is an important
contribution to the discussion concerning the Ibero±Armorican
arc (IAA) generation model. This model comes as one
of a sequence of previous ideas already published in several
papers (Bard, 1971; Matte and Ribeiro, 1975; Lefort and
Ribeiro, 1980; Ribeiro et al., 1980; Burg et al., 1981;
Brun and Burg, 1982; Julivert, 1987; Ribeiro et al., 1990;
Dias and Ribeiro, 1995; Ribeiro et al., 1995; Silva, 1997). A
common feature of the interpretations in these papers is the
great importance attributed to two major transcurrent faults:
the dextral Porto±Tomar shear zone (PTSZ) and the sinistral
Tomar±Badajoz±Cordoba shear zone (BCSZ), to explain
the extension of the Iberian structures into the Armorican
Massif in the form of trace the arcuate shape of the IAA
Superposition relations of microfabrics in the northern hanging-wall block
This study reports alternation of D2 extension-related and D3 contraction-related microfabrics in the northern
hanging wall block of a gneiss dome-like structure recognized in the Évora Massif (Ossa-Morena Zone). In the
Arraiolos – Santo Antonio de Alcorrego traverse high- to low-grade mylonites are dominant. Microfabrics related to D2
ductile deformation and M2 high-amphibolite to greenschist facies characterize an extensional shear zone with
telescoping metamorphic isograds. D2 microstructures indicate shear sense with top-to-SE. Superposition of D3
contraction developed under greenschist facies (M3) producing folding of D2 microfabrics, mylonitization of granites
along strike-slip shear zones and retrogression of M2 mineral assemblages
Comment on ‘‘Geodynamic evolution of the SW Europe
Ribeiro et al. [2007] have presented a geodynamic
view of the SW Iberia Variscides based on data from
Portugal. Their treatment of already published data is commendable,
and the knowledge gained will surely encourage
the discussion of the SWEurope Variscides. However, in our
opinion, Ribeiro et al.’s modeling and interpretation of the
Ediacaran–Lower Ordovician ( 560–470 Ma) geodynamic
evolution are of limited value. In this regard, they based their
analysis of the Ossa-Morena Zone (OMZ) on assumptions
which are contradicted by recent published data. Ribeiro et al.
ignored recent progress in the OMZ Ediacaran-Ordovician
stratigraphy and, as a consequence they misunderstood
the structure of domains overprinted by strong Variscan
(Carboniferous) deformation and metamorphism
The role of bedding in the formation of fault–fold structures,
Fold-fault structures within a major transpressional shear zone of the SW Iberian Massif were investigated by combining geological mapping,
cross-section analysis and microtectonic studies. A significant example of contractional deformation is displayed in the Portalegre-Esperanc¸a
Shear Zone (PESZ) where a heterogeneous Ordovician stratigraphic sequence, showing a strong competence contrast between quartzites,
slates and quartzo-feldspathic rocks favoured strain localization and fault nucleation that controlled fold formation. The presence of pelitic
layers within the thick-bedded quartzites had probably provided weakness zones that were more favourable for the strain localization than the
previous foliation present in the quartzites. The quartzites and the quartzo-feldspathic rocks (granites and volcaniclastic rocks) accommodated
heterogeneous high strain developing different degrees of mylonitization. The quartzites with protomylonitic textures are dominant and
represent coarse-grained siliciclastic sediments that suffered metamorphism and partial dynamic recrystallization. Ultramylonites occur
within discrete high-strain shear zones. It is probable that the strain localization in the PESZ involved both the effect of having layers of
different competence and layers or stratigraphic contacts with rocks that experienced grain size reduction dominated by cataclasis and
dislocation creep.
Folds within quartzites with sub-horizontal to gently plunging hinges vary from closed to open in thick-bedded quartzites and from tight to
closed in thin-bedded quartzites. Observed changes in structural style of deformed quartzites, slates and quartzo-feldspathic rocks are
interpreted to result from the constraints imposed by the mechanical properties of the different lithologies.
As the folds tightened during shortening, the alternating zones of contrasting competence favoured the disruption of the bedding. The
deformation history in the PESZ was dominated by thrusting and strike-slip faulting along incompetent layers that locally developed staircase
geometry and transected the lower Ordovician stratigraphic sequence. The kinematic model proposed for the PESZ is consistent with the
models of transpressional shear zones stretched along strike with the development of coeval strike-slip and low angle oblique-slip faults
associated to active buckle folds with axes parallel to the principal extension directio
The effect of loss aversion and entitlement on cheating: An online experiment
We investigate how loss aversion and entitlement influence lying. We conduct an online experiment with a cheating task in which participants draw and report a number. Participants can cheat by reporting a different number to earn a higher payoff. We vary whether participants perform (or not) a real effort task to generate their endowment before the cheating task to evoke a sense of entitlement, and whether participants can cheat for an additional gain or to avoid a loss using a 2 (earned/not earned endowment) × 2 (loss/gain) design. We find no effect of loss aversion on cheating and only weak evidence of a prior stage of real effort on lying behavior. Furthermore, we find a correlation between real effort task performance and lying, but only in the gain domain. This is the first study to look at how entitlement affects cheating behavior in both the gain and loss domains
NACA0012 benchmark model experimental flutter results with unsteady pressure distributions
The Structural Dynamics Division at NASA Langley Research Center has started a wind tunnel activity referred to as the Benchmark Models Program. The primary objective of this program is to acquire measured dynamic instability and corresponding pressure data that will be useful for developing and evaluating aeroelastic type computational fluid dynamics codes currently in use or under development. The program is a multi-year activity that will involve testing of several different models to investigate various aeroelastic phenomena. This paper describes results obtained from a second wind tunnel test of the first model in the Benchmark Models Program. This first model consisted of a rigid semispan wing having a rectangular planform and a NACA 0012 airfoil shape which was mounted on a flexible two degree of freedom mount system. Experimental flutter boundaries and corresponding unsteady pressure distribution data acquired over two model chords located at the 60 and 95 percent span stations are presented
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