Ground Penetrating Radar Investigations in the Noble Hall of São Carlos Theater in Lisbon,Portugal     

S. Fontul  M. Solla  H. Cruz  J. S. Machado  L. Pajewski 《Surveys in Geophysics》2018,39(6):1125-1147

This paper describes a study conducted by the National Laboratory for Civil Engineering of Portugal (LNEC), in cooperation with the Defense University Center at the Spanish Naval Academy and “La Sapienza,” University of Rome, to assess the health and safety conditions of the Noble Hall floor in the São Carlos National Theater (Lisbon, Portugal). In a multidisciplinary approach, extensive fieldwork was carried out. The survey included the location and characterization of beams in the various areas of the floor by using two ground penetrating radar (GPR) systems equipped with two different ground- or air-coupled antennas, local inspection openings to visually assess the geometry, timber species and conservation state of structural members, and an assessment of the conservation state of the timber beam ends using drilling equipment. All the tests performed and the results obtained are presented. The potential of using non-destructive tests for the inspection of timber cultural heritage structures, particularly GPR, is discussed, and some practical recommendations are made.  相似文献   

Low densities of sea urchins influence the structure of algal assemblages in the western Mediterranean     

Cruz Palacín  Gonzalo Giribet  Susanna Carner  Luis Dantart  Xavier Turon 《Journal of Sea Research》1998,39(3-4)

Numerous studies of interactions between urchins and algae in temperate areas have shown an important structuring effect of sea urchin populations. These studies focused almost wholly on the effect of high urchin densities on laminarian forests. In contrast, algal communities below 5–6 m depth in the northwestern Mediterranean are characterised by low sea urchin densities (<5 ind m⁻²) and the absence of laminarian forests. No previous research has addressed sea urchin/algal interactions in this type of community. To determine the effect of the most abundant echinoid species, Paracentrotus lividus, on well-established algal communities in this area, we performed a removal–reintroduction experiment in rocky patches located between 13 and 16 m depth in the northwestern Mediterranean, where sea urchin densities ranged between 0.9 and 3.4 ind m⁻². After 6 months, the cover of non-crustose algae was significantly higher in the plots from which sea urchins had been removed than in control plots (84 vs 67% cover). These removal plots reverted to their original state upon reintroduction of sea urchins. The non-crustose algae consisted of turfing and frondose forms, with the former representing some 70% of the non-crustose algal cover. Change in the cover of turfing algae was responsible for the significant increase in algal development in the sea urchin removal plots. The response of frondose algae to the treatment varied between algal species. It is concluded that grazing by P. lividus exerts a significant effect on habitat structure, even in communities with low sea urchin densities, such as those found in vast areas of the Mediterranean sublittoral.  相似文献   

Regional analysis of indirect factors affecting the recovery,degradation and deforestation in the tropical dry forests of Oaxaca,Mexico     

Francisco Guerra‐Martínez  Arturo García‐Romero  Andrea Cruz‐Mendoza  Laura Osorio‐Olvera 《Singapore journal of tropical geography》2019,40(3):387-409

This study evaluates the dynamics and identifies the indirect biophysical and socio‐economic factors related to the recovery, degradation and deforestation of the tropical dry forest (TDF) cover in the municipality of Tehuantepec, Oaxaca, Mexico. Annual rates and transition matrices were determined to identify indirect factors; the cartographic information of 25 variables with shift points were overlaid and Generalized Linear Models (GLM) were applied. The change process with the greatest impact in TDF during the study period (1993–2011) was degradation, with 10468 ha degraded (12 per cent of the initial tropical cover); recovery of coverage was the second most important change process, with 4808 ha (5.5 per cent); and deforestation was the change process with the lowest impact, with a loss of 2800 ha (3.23 per cent). The net balance was negative, with a decrease (through land degradation and deforestation) of 8460 ha (9.75 per cent). The recovery of coverage was mainly associated with biophysical factors such as land suitability and accessibility to natural vegetation. On the other hand, deforestation and degradation of coverage were associated with both biophysical and socioeconomic factors such as land suitability, accessibility to natural vegetation, migration, marginalization, population pressure, economy, education and health. The findings of this study determined the spatial distribution of forest recovery, deforestation and degradation processes at a regional level, allowing for future researchers to focus their efforts at local and landscape levels. Also, the work allows for an approximation of the factors associated with the change processes studied, hence supporting the allocation of resources for the establishment of management, conservation, development and restoration strategies of tropical dry forests at the regional level.  相似文献   

First record of the pacific fanfishpteraclis aesticola (jordan and snyder, 1901) in the tropical eastern pacific     

José De La Cruz Agüero  Víctor Manuel Cota Gómez 《Ocean Science Journal》2008,43(3):161-164

One specimen ofPteraclis aesticola was collected off San José del Cabo, Baja California Sur, México (22°54′N, 109°45′W), in March 2007. Present record is the first reported occurrence of the species in the Tropical Eastern Pacific biogeographic region (Gulf of California to southern Ecuadorian waters). Its large fan-like anal and dorsal fins and its counts of fin rays and vertebrae can distinguish the Pacific fanfish from the other species in the genus. This fish may have not yet been recorded in the region because its presence has been overlooked in the past because of rarity and lack of commercial value.  相似文献   

Exploring of the spatially varying completeness of a tsunami catalogue     

Ning  Li X.  Cheng  Chang X.  Cruz  Ana M.  Garnier  Emmanuel 《Natural Hazards》2022,110(1):191-205

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