2,250 research outputs found
Magnetostratigraphy of the Miocene continental deposits of the Montes de Castejón (central Ebro basin, Spain): geochronological and paleoenvironmental implications
A detailed magnetostratigraphic study has been carried out in the early to middle Miocene distal alluvial and lacustrine sediments of the Montes de Castejón (central Ebro Basin). The study was based on the analysis of 196 magnetostratigraphic sites sampled along a stratigraphic interval of about 240 meters. Local magnetostratigraphy yielded a sequence of 12 magnetozones (6 normal and 6 reverse) which could be correlated with the Geomagnetic Polarity Time Scale (GPTS) interval C5Cr to C5AD (between 17 and 14.3 Ma.). The sampled sedimentary sequences include the boundary between two tectosedimentary units (TSU, T5 and T6) already defined in the Ebro Basin. The magnetostratigraphy of the Montes de Castejón allows to date the T5/T6 TSU boundary at 16.14 Ma, within chron C5Cn.1n. This magnetostratigraphy also allows us to analyse in detail as well as to discuss the variations in sedimentation rates through space and time between different lacustrine environments: Outer carbonate lacustrine fringes and distal alluvial plains (Montes de Castejón sections) show higher sedimentation rates than offshore lacustrine areas (San Caprasio section, 50 km east of Montes de Castejón)
Transfinite order dimension
We give two different transfinite extensions of the covering dimension based on the Borst's order of certain families of boundaries of basic open sets. We compare them and we study their main properties
Dimension, inverse limits and GF-spaces
In this paper we characterize (covering) dimension in
metrizable spaces in terms of fractal structures. We will also
study dimension for compact metric spaces, giving a theorem relating dimension and a certain class of inverse limits, similar to
that of Freudenthal
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Special Economic Zones, Global Value Chains, and the Degree of Economic Linkages in the Dominican Republic
The Dominican Republic is often considered an example of the successful implementation of Special Economic Zones (henceforth SEZs) in the Western hemisphere. The zones fueled economic growth during the 1980s and 1990s and, while they experienced a sharp decline in employment due in part to the expiry of the end of the Multi-Fiber Agreement and stronger international competition in the textile and apparel industry in 2005, signs of recovery have been observed since 2009. Surgical equipment, chemicals and plastics, and footwear have recently emerged as the new drivers of export dynamism in the zones (World Bank, 2015). The objective of this report is to inform the policy discussion around the developmental impact of SEZs in the Dominican Republic by empirically assessing i) the implications of regulatory reforms aimed at complying with WTO disciplines regarding the elimination of incentives conditioned on export performance for SEZs firms, ii) the extent to which SEZs participate in Global Value Chains, and iii) their linkages with domestic suppliers. The report is organized as follows: The second section presents the historical importance of SEZ as an engine of economic growth in the country. The third section depicts the structural shift in terms of production in SEZs and evaluates the degree of value addition taking place in the Dominican Republic. The fourth section evaluates the degree and evolution of linkages between SEZs and local firms. The fifth section shows the impact of the regulatory changes in the SEZ regimen undertaken to comply with WTO disciplines. Finally, some conclusions and policy recommendations are presented in section six
Metastable anisotropy orientation of nematic quantum Hall fluids
We analyze the experimental observation of metastable anisotropy resistance
orientation at half filled quantum Hall fluids by means of a model of a quantum
nematic liquid in an explicit symmetry breaking potential. We interpret the
observed ``rotation'' of the anisotropy axis as a process of nucleation of
nematic domains and compute the nucleation rate within this model. By comparing
with experiment, we are able to predict the critical radius of nematic bubbles,
. Each domain contains about electrons.Comment: 10 pages, 8 figures, final version as will appear in PR
Are bullying behaviors tolerated in some cultures? Evidence for a curvilinear relationship between workplace bullying and job satisfaction among Italian workers
Since the early 1990s, increasing attention has been paid to the impact of workplace bullying on employees’ well-being and job attitudes. However, the relationship between workplace bullying and job satisfaction remains unclear. This study aims to shed light on the nature of the bullying-job satisfaction relationship in the Italian context (n = 1,393 employees from different organizations). As expected, the results revealed a U-shape curvilinear relationship between workplace bullying and job satisfaction after controlling for demographic variables. In contrast to the curvilinear model, the results support a negative linear relationship between workplace bullying and psychological well-being, in which higher exposure to negative acts at work is associated with diminished well-being. In addition, gender and job position significantly predicted mental health scores where men and managers reported a better psychological well-being than women, blue-collar, and white-collar employees. Practical and theoretical implications are discussed according to these results.info:eu-repo/semantics/acceptedVersio
Magnetite: Raman study of the high-pressure and low-temperature effects
We report the results of a low-temperature (300K-15K) high-pressure (up to
22GPa) Raman study of the Verwey transition in magnetite (Fe3O4). We use
additional Raman modes observed below the Verwey transition to determine how
the transition temperature changes with the quasihydrostatic pressure. Increase
of the pressure results in the linear decrease of the Verwey transition
temperature, with no discontinuity. The corresponding pressure coefficient
dTV/dP is found to be ~ -5.2 K/GPa. Such a decrease is substantially larger
than the one predicted by the mean-field Coulomb interaction model of the
transition
Sedimentology and depositional architecture of tufas deposited in stepped fluvial systems of changing slope: Lessons from the quaternary añamaza valley (Iberian Range, Spain)
The Pleistocene and Holocene tufas of the Añamaza valley (stepped build-ups, up to 70 m thick, along the valley) consist of several depositional stages separated by erosional surfaces. Eight associations of tufa and related carbonate facies, plus minor polygenic detrital facies, represent the processes that occurred in different fluvial and related environments. The bedrock lithology and structure controlled the location of the knickpoints along the valley and allowed separation of two stepped stretches with distinct conceptual facies models. The moderate-slope model includes extensive standing-water areas dammed by barrage-cascades. In the lakes, bioclastic silts, sands and limestones along with phytoclastic and marly, at places peaty, sediments formed. Abundant stem phytoherms account for extensive palustrine areas. The high-slope model consists of smaller dammed areas between close-up cascades and barrage-cascades, which were composed primarily of moss phytoherms and phytoclastic tufas. An outstanding feature is the extensive steep reach with phytoclastic and polygenic detrital sediments, and stepped cascades consisting of stromatolitic and moss phytoherms. There, the steep slope limited the preservation of stem phytoherms and favoured erosion. The geometry and thickness of the sedimentary fill (wedge-shaped units composed of cascade and barrage-cascade deposits downstream, and dammed and gentle-sloped channel deposits upstream) are therefore different for each model. Multi-storey wedges are a distinctive feature of the high-slope model. The initial knickpoint geometry and the tufa aggradation/progradation ratio on such steep surfaces (for example, related to changes in discharge) controlled the growth style of the cascades or barrage-cascades and, hence, the extent, thickness and vertical evolution of the upstream deposits. The sedimentological attributes and stable-isotope composition of the carbonate facies suggest a higher and more variable precipitation/evaporation ratio during the Pleistocene than during the Holocene, consistent with an overall decrease in the river discharge. This evolution was coupled with warm conditions, which prevailed during the stages of tufa formation. These results may help to assess architectural patterns in interpreting other basins, and underscore the significance of tufas as records of past hydrology and climate
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