Management of Cultural Heritage Sites Using Remote Sensing Indices and Spatial Analysis Techniques

Sustainable management and exploitation policies as well as suitable conservation and mitigation strategies are mandatory to preserve cultural heritage and to reduce threats, weathering phenomena, and human actions that may produce significant deterioration and alteration of cultural heritage and “its environment”. In this context, remote sensing technologies can offer useful data to timely update information and documentation and set up reliable tools for systematic monitoring of cultural properties. In this study, multi-temporal and multi-sensor satellite data from Corona, Landsat, Spot, Quickbird, and Sentinel-2A have been exploited along with spatial analysis to investigate the area of the Theban temples at west Luxor (Egypt), severely threatened by uncontrolled urban sprawl. The results from our analyses showed that the urban expansion continuously occurred during the whole investigated period causing an increasing in urban areas around (1) 1.316 km² from 1967 to 1984, (2) 1.705 km² from 1984 to 2000, (3) 0.978 km² from 2000 to 2003, (4) 2.314 km² from 2003 to 2011, and (5) 1.377 km² from 2011 to 2017. The random urban expansion caused bad sewage networks and high groundwater depth which in turn affected the archaeological areas directly (as evident on a landscape view) and indirectly by causing changes (growing) in the level of ground water depth and increasing and accelerating weathering phenomena. The quantification and mapping of urban sprawl enabled us not only to quantify and spatially characterize urban sprawl but also to create a model to mitigate the impact and provide some operational recommendations to protect the archaeological site. Outcomes from our analysis pointed out that today the tremendous availability of advanced remote sensing data has opened new prospectives unthinkable several years ago.     

Variations in the pallial organ sizes of the invasive oyster, Crassostrea gigas, along an extreme turbidity gradient

Spatial size variations of labial palps, gills and the adductor muscle of the invasive feral oyster, Crassostrea gigas, were studied along two gradients of suspended particulate matter (SPM) concentrations in the temperate macrotidal Bourgneuf Bay, (annual mean SPM concentration gradient of 21.0–154.0 mg l⁻¹) and the adjacent Loire Estuary (annual mean SPM concentration gradient of 24.1–630.4 mg l⁻¹) on the French Atlantic Coast. The gill-to-palp (G:P) ratios decreased with increasing turbidity, both in the bay and the estuary. Changes in G:P ratios were chiefly related to palp area variations, increasing gradually from low turbidity to very high-turbidity sites, while gill area showed no clear relationship with turbidity conditions. The G:P ratio, showing a significant relationship (r² = 0.97) with SPM concentrations, is proposed as a pallial organ index of oyster acclimation to turbidity conditions. The area of the striated part of the adductor muscle was always greater than that of the smooth one, and adductor muscle area tended to decrease when SPM concentration increased. These observations show the morphological capacity of the oyster C. gigas to tolerate SPM concentrations above the feeding cessation thresholds previously determined experimentally. They also suggest that pallial organ size variations could help explain the success of recent feral oyster invasions in temperate turbid ecosystems.     

Buoyancy-controlled eruption of magmas at Mt Etna

Buoyancy controls the ability of magma to rise, its ascent rate and the style of the eruptions. Geophysical, geological and petrological data have been integrated to evaluate the buoyancy of magmas at Mt Etna. The density difference between host rocks and magmas is mainly related to the amount of H₂O dissolved in the magma and to the bubble‐liquid separation processes. In the depth interval 22–2 km b.s.l. highly hydrated (H₂O ～ 3%) basaltic magmas or mixtures of bubbles + liquid have positive buoyancy and rise rapidly. Conversely, bubble‐depleted liquids, with an intermediate H₂O content (～ 1.5%), having neutral buoyancy, will spread out and form magmatic reservoirs at different depths until cooling/crystallization further modify composition and density. These different processes account for the magma compositions, location of magmatic reservoirs as determined by geophysical methods, and the complex eruptive cycles (slow effusions, fire fountains and Plinian eruptions) that have been observed in the history of the volcano.     

Cyanobacterial blooms in estuarine ecosystems: characteristics and effects on Laeonereis acuta (Polychaeta, Nereididae)

In January of 2003, a cyanobacterial bloom in the Patos' Lagoon (Southern Brazil) (32 degrees 05'S-52 degrees 12'W) was observed. Water samples were taken to identify the composition and abundance of the bloom, as well as the occurrence of toxins. The effects of this occurrence on the estuarine worm Laeonereis acuta (Polychaeta, Nereididae) was also evaluated. Predominance of cyanobacteria, particularly Anabaena trichomes ( approximately 2.5.10(6) individuals per liter) was observed, and low concentrations of microcystins and anticholinesterasic toxins were detected. Augmented levels of lipid hydroperoxides (LPO) and glutathione-S-transferase activity, and lowering of total protein content were also observed in organisms collected during the bloom event. Although non-toxic, the cyanobacterial bloom could augment the cycle of hyper-oxygenation and hypoxia in the water. During hyperoxia, L. acuta, an oxyconformer, should consume more oxygen, thus augmenting the rate of reactive oxygen species generation. A repeated cycle of hyper-oxygenation and hypoxia would finally induce oxidative stress, as evidenced by the high levels of LPO and glutathione-S-transferase activity.     

Effects of artificial and natural recharge on chemical equilibrium in the Cerro Prieto reservoirs, Baja California, México

Chemical equilibrium modeling studies of two aquifers in the western part of the Cerro Prieto (CP-I) geothermal field were performed to obtain the activities of the main ions and complexes by using the EQQYAC program. The results provided a pH of 6.44 for the deep aquifer, which is slightly higher than the value of 5.5 found for the shallower reservoir. In the northern part of the field, the reservoir pH has decreased up to 1.5 units compared to that modeled for 1990. Variations of pH with respect to time were also found to occur in the southern part of the field. In spite of the large changes in hydrodynamic conditions occurring in the reservoir due to exploitation, the equilibrium between both K- and Na-feldspars and between K-feldspar and K-mica seems to control the chemical composition of the fluids, in both reservoirs.     

Compact Groups of Galaxies: Evolution of the Stellar Population

We present a study focusing on the nature of compact groups (CGs) through the study of their elliptical (E) galaxies. Parameters describing the internal dynamics and the stellar populations of the galaxies are compared with their counterparts in other environments. Our sample has24 bright E galaxies located in the core of Hickson CGs and 11 bright ‘bona fide’ Es, located in the field or very loose groups. Their spectra were obtained with the 2.1 m Telescope at KPNO and have a 4.1 Å resolution over the wavelength range 3500–7000 Å. We have found that, from the dynamical point of view, E galaxies in CGs are essentially similar to those in dense clusters. Moreover, the stellar populations of Es in CGs seem to be older and less metal rich than those in the field, behaviour which has also been observed by Rose et al. (1994).     

Fluctuation analysis of solar radio bursts associated with geoeffective X-class flares

High temporal resolution solar observations in the decimetric range (1–3 GHz) can provide additional information on solar active regions dynamics and thus contribute to better understanding of solar geoeffective events as flares and coronal mass ejections. The June 6, 2000 flares are a set of remarkable geoeffective eruptive phenomena observed as solar radio bursts (SRB) by means of the 3 GHz Ondrejov Observatory radiometer. We have selected and analyzed, applying detrended fluctuation analysis (DFA), three decimetric bursts associated to X1.1, X1.2 and X2.3 flare-classes, respectively. The association with geomagnetic activity is also reported. DFA method is performed in the framework of a radio burst automatic monitoring system. Our results may characterize the SRB evolution, computing the DFA scaling exponent, scanning the SRB time series by a short windowing before the extreme event. For the first time, the importance of DFA in the context of SRB monitoring analysis is presented.