350 research outputs found

    The Gulf of Cádiz: thrusting or strike-slip motion?

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    In the Gulf of Cádiz (SW Iberian Peninsula) the boundary between Eurasia and Nubia plates corresponds to a narrow band well defined by the seismicity, where large earthquakes (M>7.0) may be associated to N-S to NNW-SSE horizontal compression due to the convergence between the two plates. Most of these earthquakes are at shallow depth (less than 40 km), with some foci at intermediate-depth, showing E-W distribution and limited by a narrow band less than 20 km wide that broadens as we move to the Strait of Gibraltar. In this area the lithospheric material is relatively rigid and the stresses are released by larger earthquakes. General tectonic models proposed for the Azores-Tunisia plate boundary explain fairly well the nature of its seismicity and tectonic motions; however, details of some of its aspects are still poorly understood and controversial. Zittelini et al. (2009) has recently proposed for the Gulf of Cádiz, transcurrent-transpressional motion along a long strike slip fault based on multichannel seismic reflection surveys. However, this contradicts the compressional motion and reverse faulting of large 1755 Lisbon earthquake (~Mw9), which generate a large tsunami and the recent moderate (Mw>6.0) in 1964, 2007 and 2009 and large (Mw= 8.0) in 1969 earthquakes occurred in the region. These earthquakes show thrusting motion along E-W faults with the southern block going under, corresponding to horizontal NW-SE compression, and they can be related directly to the plate convergence between Nubia and Iberia. References Zitellini et al., 2009. The quest for the Africa–Eurasia plate boundary west of the Strait of Gibraltar. Earth and Planetary Science Letters 280 (2009) 13–50

    Motivations for tourism adoption by vineyards worldwide: A literature review

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    Wine tourism has been increasingly implemented by wineries in several countries around the world. This article aims at identifying the motivations for wine tourism adoption by wineries around the world through a narrative bibliographic review. This paper includes an analysis of articles related to the subject taken from the Web of Science database. In this article, we identified the objectives, methods, and conclusions reached by authors, who researched wine tourism. The bibliographic survey based on the keywords “wine” and “tourism”, resulted, after refining it by reading titles and abstracts, in 20 articles. The results show that most wineries in the studied sample adopt wine tourism as a strategy to achieve marketing-related benefits. Also, some wineries are motivated by the competitive advantage, economic development and increasing demand for such service. It is concluded that wineries are increasingly seeking to adapt to current consumer demands. From the perception of the importance of service experience offered to the consumer, mainly in the product sale

    Estabilidade De Agregados Em Latossolos Sob Plantas De Cobertura Em Rotação Com Soja E Milho

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    The objective was to evaluate the effect of different covers on the stability of soil aggregates in two areas of Oxisols, grown in rotation with crops of soybean and corn. The experiments were installed in Votuporanga, SĂŁo Paulo, Brazil and SelvĂ­ria, Mato Grosso do Sul, Brazil in March 2008. The experimental design was a randomized block with four replicates and the following cover crops in different spending ha-1 seeds, were the treatments: Sorghum bicolor, 6, 7 and 8 kg ha-1; Pennisetum americanum, 10, 15 and 20 kg ha-1; S. sudanense, 12, 15 and 18 kg ha-1; hybrid of S. bicolor and S. sudanense, 8, 9 and 10 kg ha-1; Urochloa ruziziensis, 8, 12 and 16 kg ha-1; plus, control treatment with spontaneous vegetation. We evaluated the dry matter yield of different covers and were separate classes of soil aggregates and calculated the average diameter. It is noted that the cover crops had similar behavior on aggregates stability in the surface layer, and in the greater depth, the S. sudanense was more efficient in improving the class mean diameter between 2.0-1.0 mm, in Votuporanga, and the P. americanum was more efficient from 4.0 to 2.0 mm and 2.0-1.0 mm in SelvĂ­ria. Lower spending seeds was more promising on aggregate stability.11315616

    Alterações Físicas Em Latossolos Cultivados Com Plantas De Cobertura Em Rotação Com Soja E Milho

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    This study was conducted to evaluate the effect of different covers, grown in rotation with soybean and corn on the physical attributes of two Oxisols. The experiments were installed in Votuporanga, SP, Brazil and SelvĂ­ria, MS, Brazil in March 2008, after conventional tillage. The experimental design was a randomized complete block with four replications, using the following cover crops at different amounts of seeds: Sorghum bicolor, Pennisetum americanum, S. sudanense, hybrid of S. bicolor with S. sudanense, Urochloa ruziziensis and a control with spontaneous vegetation. We evaluated the dry matter yield of different covers, and macroporosity, microporosity, total porosity and bulk density, in the layers of 0-0.05, 0.05-0.20 and 0.20-0.40 m. It concludes that, different covers plants and seed amounts used for grains, seeds and forage after two years did not cause effects on some soil physical properties of the two Oxisols.11314915

    The role of source and site effects on structural failures due to Azores earthquakes

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    The existing building stock in Azores islands (Portugal) was severely damaged during 1980 and 1998 earthquakes. Structural failure was probably caused by a combination of factors that are not yet well understood. Earthquake source characteristics, site effects and structural vulnerability may be some of those factors. However, it is very difficult to assess the influence of each factor on structural failure, mainly because recorded accelerograms used in nonlinear structural analysis are influenced by both source characteristics and site conditions. The only way to overcome this problem is to control each factor individually which can be done by using simulated accelerograms. In our previous work, stochastic ground motion simulations results were compared with earthquake records. Results seem to indicate that simulated accelerograms can match recorded accelerograms if proper source characteristics and geological site conditions are selected. In this work, simulated accelerograms were used for seismic nonlinear structural analysis. Simulations were carried out considering several 1980 Azores earthquake possible sources and for different geological site conditions. Simulated accelerograms were then used to evaluate the structural nonlinear behaviour of a reinforced concrete structure and of two masonry structures. The results of this work highlight the importance of site conditions and earthquake source characteristics to the determination of the design seismic actions of Azores islands. This work was performed in the scope of “Strong ground motion for Azores – SiGMA” project, financed by the Portuguese Science and Technology Foundation (PTDC/CTE-GIX/121957/2010)

    Whole-system metabolism and CO<sub>2</sub> fluxes in a Mediterranean Bay dominated by seagrass beds (Palma Bay, NW Mediterranean)

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    The relationship between whole-system metabolism estimates based on planktonic and benthic incubations (bare sediments and seagrass, Posidonia oceanica meadows), and CO2 fluxes across the air-sea interface were examined in the Bay of Palma (Mallorca, Spain) during two cruises in March and June 2002. Moreover, planktonic and benthic incubations were performed at monthly intervals from March 2001 to October 2002 in a seagrass vegetated area of the bay. From the annual study, results showed a contrast between the planktonic compartment, which was heterotrophic during most of the year, except for occasional bloom episodes, and the benthic compartment, which was slightly autotrophic. Whereas the seagrass community was autotrophic, the excess organic carbon production therein could only balance the excess respiration of the planktonic compartment in shallow waters (<10 m) relative to the maximum depth of the bay (55 m). This generated a horizontal gradient from autotrophic or balanced communities in the shallow, seagrass-covered areas of the bay, to strongly heterotrophic communities in deeper areas, consistent with the patterns of CO2 fields and fluxes across the bay observed during the two extensive cruises in 2002. Finally, dissolved inorganic carbon and oxygen budgets provided NEP estimates in fair agreement with those derived from direct metabolic estimates based on incubated samples over the Posidonia oceanica meadow

    The Azorean Biodiversity Portal: an internet database for regional biodiversity outreach

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    Copyright © 2010 The Natural History Museum.There is a growing interest in academia to provide biodiversity data to both the scientific community and the public. We present an internet database of the terrestrial lichens, bryophytes, vascular plants, molluscs, arthropods, vertebrates and coastal invertebrates of the Azores archipelago (Portugal, North Atlantic): the Azorean Biodiversity Portal (ABP, http://www.azoresbioportal.angra.uac.pt/). This is a unique resource for fundamental research in systematics, biodiversity, education and conservation management. The ABP was based on a regional species database (ATLANTIS), comprised of grid-based spatial incidence information for c. 5000 species. Most of the data rely on a comprehensive literature survey (dating back to the 19th century) as well as unpublished records from recent field surveys in the Azores. The ABP disseminates the ATLANTIS database to the public, allowing universal, unrestricted access to much of its data. Complementarily, the ABP includes additional information of interest to the general public (e.g. literature on Macaronesian biodiversity) together with images from collections and/or live specimens for many species. In this contribution we explain the implementation of a regional biodiversity database, its architecture, achievements and outcomes, strengths and limitations; we further include a number of suggestions in order to implement similar initiatives

    Human-robot collaboration (HRC) with vision inspection for PCB assembly

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    Flexibility and speed in the development of new industrial machines are essential factors for the success of capital goods industries. When assembling a printed circuit board (PCB), since all the components are surface-mounted devices (SMD), the whole process is automatic. However, in many PCBs, it is necessary to place components that are not SMDs, called pin through-hole components (PTH), having to be inserted manually, which leads to delays in the production line. This work proposes and validates a prototype work cell based on a collaborative robot and vision systems whose objective is to insert these components in a completely autonomous or semi-autonomous way. Different tests were made to validate this work cell, showing the correct implementation and the possibility of replacing the human worker on this PCB assembly task.ERDF - European Regional Development Fund(45070

    Inversion of Tsallis' q-Fourier Transform and the complex-plane generalization

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    We introduce a complex q-Fourier transform as a generalization of the (real) one analyzed in [Milan J. Math. {\bf 76} (2008) 307]. By recourse to tempered ultradistributions we show that this complex plane-generalization overcomes all troubles that afflict its real counterpart.Comment: 23 pages, no figure
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