Polychaete Communities Related to Plant Covering in the Médiolittoral and Infralittoral Zones of the Balearic Islands (Western Méditerranean)     

Rafael  Sarda 《Marine Ecology》1991,12(4):341-360

Abstract. The polychaete fauna of the subtidal in the médiolittoral and the infralittoral hard bottom zones of the Balearic Islands at depths from 0 to 40m contained 220 species. Five different polychaete communities could be identified by changes in abundance, species richness, species composition, diversity, and trophic structure. In the very clear waters of these islands the infralittoral zone extends to a depth of 40 m and allows us to investigate whether former proposed models of polychaete distribution can be extended to this particular situation.  相似文献   

Effects of Soft Corals on Scleractinian Coral Recruitment. II: Allelopathy, Spat Survivorship and Reef Community Structure   总被引：1，自引：0，他引：1  

Mauro Maida  Paul W. Sammarco  & John C. Coll 《Marine Ecology》2001,22(4):397-414

Abstract. Two field experiments were performed on the Great Barrier Reef, Australia, at Orpheus Island and Lizard Island, respectively, to investigate the effects of allelopathic soft corals on survivorship and community structure of scleractinian coral spat. Ceramic tiles were placed around the allelopathic soft corals Sinularia flexibilis (Quoy & Gaimard 1833) and Sarcophyton glaucum (Quoy & Gaimard 1833), and controls. One control consisted of settlement plates surrounding a scleractinian coral (non‐allelopathic planktivore); another control had no adult soft or scleractinian coral present. The experimental soft corals affected the recruitment of various taxonomic groups of coral spat differentially, as evidenced by the diversity of coral spat settling in treatments and controls. At Orpheus Island (O.I., n = 1038 spat) and Lizard Island (L.I., n = 7032 spat), there were significant differences between recruitment success of the two dominant coral taxa, Pocilloporidae (O.I., 61.4 %; L.I., 20.5 %) and Acroporidae (O.I., 33.7 %; L.I., 53 %). Settlement plates exposed to Sinularia flexibilis at either site had the lowest proportion of acroporid recruits. Diversity indices (Shannon‐Wiener Indices) varied significantly between treatments at both Orpheus and Lizard Islands. This appears to be due to selective inhibition of acroporid spat by Sinularia flexibilis at both sites. Growth of coral spat was higher on settlement plates in the presence of Sarcophyton at Lizard Island. Settlement of most associated epibiota was generally inhibited under these conditions. Coral spat survivorship was highest in the presence of Sinularia at Orpheus ­Island; at Lizard Island, this was the case with the Sarcophyton treatment. Higher survivorship, and in some cases growth, of coral spat near soft corals was apparently due to reduced competition for space between spat and associated epibiota. This hypothesis is supported by the results of a sister experiment where a coating of Sinularia flexibilis extract on settlement tiles significantly decreased fouling by sessile epibiota. Soft corals have an allelopathic effect on recruitment and early development of scleractinian corals and, consequently, on early coral reef community succession.  相似文献   

Soil liquefaction potential induced by the andalusian earthquake of 25 December 1884     

José R. Arango  Rafael Blazquez  José Chacon  Carlos López Casado 《Natural Hazards》1995,12(1):1-17

On 25 December 1884, an earthquake of epicentral intensityI ₀ = IX in the MSK scale caused great damage in a large area in the provinces of Granada and Málaga, in the south of Spain. The reports of the Spanish, Italian and French Commissions that studied the earthquake described ground phenomena in seven different sites which can be identified as soil liquefaction.By means of dynamic penetration tests carried out in the above sites, the corresponding soil profiles (based on SPT data and water table depth) were established, and the occurrence of liquefaction was proved in five out of seven of these sites. Also, the intensities at such locations and the magnitude of the earthquake were estimated.From the geotechnical data and the cyclic stress ratio induced by the earthquake, liquefaction conditions were confirmed in all the five sites which presumably liquefied. Then, possible values of the minimum ground surface accelerations necessary for the onset of liquefaction at each location were calculated. The results obtained were completed with data reported in six liquefaction case studies from Japan and the United States, from which design charts relating soil acceleration with normalized SPT values for different intensity levels were drawn.Finally, by using standard attenuation curves, the above data were translated into epicentral distances, and good agreement with the known epicentral area was found. As a result, a consistent approach for liquefaction hazard and source location problems has been developed. The proposed method combines in its formulation historical evidence and earthquake engineering techniques.  相似文献   

An Interdisciplinary Methodology for the Characterization and Visualization of the Heritage of Roadway Corridors          下载免费PDF全文

Mar Loren‐Méndez  Rafael Mata‐Olmo  Rita Ruiz  Daniel Pinzón‐Ayala 《Geographical review》2016,106(4):489-515

Roads, particularly since the advent of motorized traffic, have hugely impacted contemporary landscapes. Although their significance was noted in the 1980s, specific roadway‐heritage studies are scarce. Research in different disciplines has identified certain features of roads, but an integrated approach to roadway heritage or a consensus on what this constitutes are lacking. This article proposes an interdisciplinary methodology to assess roadway heritage. Roadways are interpreted within the framework of semantic openness that currently characterizes heritage studies, territory being the basic element of interpretation. Rather than a fragmented approach to conservation, the research defines integrated heritage configurations where natural, cultural, and historical features combine to produce a cohesive form of heritage. GIS (Geographical information systems) technology is used with an online database to assess the complexity of roadway heritage. ICT (Information and communications technology) strategies to raise public awareness are outlined. The methodology is applied to assess the historical N‐340 Mediterranean roadway corridor in Spain.  相似文献   

Geomechanical Characterization of Marcellus Shale     

Rafael Villamor Lora  Ehsan Ghazanfari  Enrique Asanza Izquierdo 《Rock Mechanics and Rock Engineering》2016,49(9):3403-3424

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The Baza Fault: a major active extensional fault in the central Betic Cordillera (south Spain)   总被引：2，自引：0，他引：2  

P. Alfaro  J. Delgado  C. Sanz de Galdeano  J. Galindo-Zaldívar  F. J. García-Tortosa  A. C. López-Garrido  C. López-Casado  C. Marín-Lechado  A. Gil  M. J. Borque 《International Journal of Earth Sciences》2008,97(6):1353-1365

In the Guadix-Baza Basin (Betic Cordillera) lies the Baza Fault, a structure that will be described for the first time in this paper. Eight gravity profiles and a seismic reflection profile, coupled with surface studies, indicate the existence of a NE-dipping normal fault with a variable strike with N-S and NW-SE segments. This 37-km long fault divides the basin into two sectors: Guadix to the West and Baza to the East. Since the Late Miocene, the activity of this fault has created a half-graben in its hanging wall. The seismic reflection profile shows that the fill of this 2,000–3,000 m thick asymmetric basin is syntectonic. The fault has associated seismicity, the most important of which is the 1531 Baza earthquake. Since the Late Tortonian to the present, i.e. over approximately the last 8 million years, extension rates obtained vary between 0.12 and 0.33 mm/year for the Baza Fault, being one of the major active normal faults to accommodate the current ENE–WSW extension produced in the central Betic Cordillera. The existence of this fault and other normal faults in the central Betic Cordillera enhanced the extension in the upper crust from the Late Miocene to the present in this regional compressive setting.  相似文献   

Joint interpretation of the hydrochemistry of two neighbouring basins by N-way multivariate methods     

Rosario Soledad Barranquero  Marcelo Raúl Varni  Rafael Pardo  Marisol Vega  María Emilia Zabala  Víctor Alejandro Ruiz de Galarreta 《Environmental Earth Sciences》2016,75(4):335

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Evidence of an atmospheric forcing on bacterioplankton and phytoplankton dynamics in a high mountain lake     

Elvira Pulido-Villena  Isabel Reche  Rafael Morales-Baquero 《Aquatic Sciences - Research Across Boundaries》2008,70(1):1-9

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Photoprotective role of inflorescence and UV-radiation effects on pollen viability of different freshwater plants     

Rafael M. Conde-Álvarez  Félix L. Figueroa  Elena Bañares-España  José M. Nieto-Caldera 《Aquatic Sciences - Research Across Boundaries》2008,70(1):57-64

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Analytical evaluation of structural component limit state probabilities     

Xavier Romão  João Guedes  Aníbal Costa  Raimundo Delgado 《Bulletin of Earthquake Engineering》2008,6(2):309-333

Probabilistic seismic assessment requires extensive computational effort resulting from variability both in input ground motions and mechanical properties. Nonetheless, such methodologies are of considerable importance, namely for pre-earthquake disaster planning or development of retrofitting programs. A framework for the analytical definition of closed form expressions for exceedance probabilities of structural component limit states, defined by limit values of structural response parameters, is proposed herein. The definition of these expressions is based on the probabilistic representation of the ground motion intensity and on the establishment of suitable expressions characterizing the evolution of structural demand with increasing earthquake intensity. Distinction is made between deformation-based and force-based structural parameters in the definition of such relations. Within the proposed framework, the limit states are defined by single deterministic thresholds of structural response quantities at the component level, as defined in structural codes. Different approaches are also discussed to account for the randomness of the mechanical properties and ground motion input within the proposed methodology. An application of the assessment of different limit state probabilities of members from a reinforced concrete building is presented, for which limit states and limit state capacities are defined according to the upcoming Part 3 of the Eurocode 8. Although the presented application only deals with member chord rotation and shear force limit state probabilities, the proposed methodology can be generalized to other deformation-based and force-based structural parameters.  相似文献