Histopathologic biomarker response of clam, <Emphasis Type="Italic">Ruditapes decussates</Emphasis>, to organophosphorous pesticides reldan and roundup: A laboratory study

Clam Ruditapes decussates was used as a biomonitoring organism to measure the potential impact of pollution. The present study investigated histological alterations of R. decussates following a long-term exposure to a sublethal-level of pesticides Reldan and Roundup. The clams were taken to the laboratory and kept for days to adjust to a continuous closed flow system with quality water control. After the adjustment period, clams were exposed either to sublethal concentrations of Reldan (0.6 μl L^?1) or Roundup (1.1 μl L^?1) for 90 days. Clams were taken to determine the histological damage at 30, 60 and 90 days. Most histological alterations were highly localized in the glandular cells of the gills, mantle tissues and digestive gland; secretions of glandular cells were found to be increased by increasing the time of exposure. Histopathological results showed the activation of resistance mechanisms that allowed the clams to survive under sublethal stresses. Thus, histological changes on localized tissues were sensitive and they have positive correlation to the time of exposure to the pesticides, suggesting that they may serve as biomarkers for Reldan and Roundup exposures.     

Interpretation of Magnetic Data Through Particle Swarm Optimization: Mineral Exploration Cases Studies

Natural Resources Research - This paper emphasizes the use of the particle swarm optimization to infer second moving average residual magnetic anomalies. This approach was used to remove the impact...     

Trace and REE element geochemistry of fluorite and its relation to uranium mineralizations,Gabal Gattar Area,Northern Eastern Desert,Egypt

Uranium mineralizations occur and form in a broad range of geologic setting and age, including magmatic to surfacial conditions, and there are numerous controls on their transportation and deposition, such as redox, pH, ligand concentration, complexation, and temperature. These temporal and spatial variations have caused a range of ore deposit mineral assemblages. Consequently, understanding their conditions of formation is still in its infancy. This research reports rare earth elements (REE) and trace elements of fluorite associated with hexavalent uranium mineralizations and tests of genetic models for the deposits. These data contribute to a better understanding of the variables controlling fluorite formation and uranium ore composition through understanding the evolution of these ore-forming hydrothermal systems. Fluorite in Gabal Gattar granite occurs as disseminations and/or thin veinlets and encrustations filling some uranium mineralized fissures and fractures along the northern margin of host granite mass. In the U-poor samples, fluorite forms well-developed large crystals that are commonly zoned. The zones are represented by alternating colorless and violet zones, and the outer zones are frequently dark violet. In the U-rich samples, fluorite is usually anhedral, unzoned, and has a dark violet color. The results of analysis of REE and trace element contents of fluorites using laser ablation inductively coupled plasma mass spectrometry indicate that total REE in the anhedral unzoned fluorite are elevated compared to the well developed zoned fluorite, and also total REE in dark violet zones of zoned fluorite are elevated with respect to the colorless zones. The fluorites and host granite are generally characterized by strongly negative Eu anomalies and slightly negative or chondritic Ce anomalies. Accordingly, REE patterns of the fluorite and host granite are roughly alike, indicating that the source of REE and trace elements of hydrothermal fluids is the host granite leached by fluids. Y/Y*, Ce/Ce,* and Eu/Eu* patterns show that fluorite clearly records the compositional evolution of the hydrothermal solutions that have transferred trace and REE from host granite during the fluid–wall rocks interactions. The high uranium contents of fluorite in Gabal Gattar granite suggest that parent fluids bearing fluorine have interacted with host granite to leach uranium from the accessory minerals of granite and tetravalent uranium minerals in reduced or weakly oxidized zones.     

Determination of potential runoff coefficient for Al-Baha Region,Saudi Arabia using GIS

The curve number (CN) is a hydrologic parameter used to describe the stormwater runoff potential for drainage areas, and it is a function of land use, soil type, and soil moisture. This study was conducted to estimate the potential runoff coefficient (PRC) using geographic information system (GIS) based on the area’s hydrologic soil group, land use, and slope and to determine the runoff volume. The soil map for the study area was developed using GPS data carried on to identify the soil texture to be used in building a soil hydrological groups map. Unsupervised and supervised classifications were done to Landsat 5/7 TM/ETM image to generate land-use and land-cover map. This map was reclassified into four main classes (forest, grass and shrub, cropland, and bare soil). Slope map for Al-Baha was generated from a 30-m digital elevation model. The GIS technique was used to combine the previous three maps into one map to generate PRC map. Annual runoff depth is derived based on the annual rainfall surplus and runoff coefficient per pixel using raster calculator tool in ArcGIS. An indication that in the absence of reliable ground measurements of rainfall product, it can satisfactorily be applied to estimate the spatial rainfall distribution based on values of R and R ² (0.9998) obtained. Annual runoff generation from the study area ranged from 0 to 82 % of the total rainfall. Rainfall distribution in the study area shows the wise use of identifying suitable sites for rainwater harvesting, where most of the constructed dams are located in the higher rainfall areas.     

Spatial rules that generate urban patterns: Emergence of the power law in the distribution of axial line length

This paper studies emergence/generation of power law in rank-order distribution of axial line length, which is a global pattern observed in real cities, due to interaction of a set of seven simple spatial rules at a local scale. These rules and their interactions form a model expected to simulate the morphological structure of free spaces in unplanned organic pedestrian small cities. Effects of each of the seven rules are discussed through repeated simulations of eight possible combinations of the rules, using a bottom-up process. The results show that the rules generate environments with statistically stable rank-order distribution of axial line length that follows the power law. It means that the axial maps of the simulated environments have a scale-free hierarchical structure such that their distributions lean toward short axial lines. It also represents dominance of local spatial structure, as the model renders a faster rate of growth at a local scale while allowing a steady growth at a global scale.     

Effects of the non-extensive parameter on the propagation of ion acoustic waves in five-component cometary plasma system

Some important evolution nonlinear partial differential equations are derived using the reductive perturbation method for unmagnetized collisionless system of five component plasma. This plasma system is a multi-ion contains negatively and positively charged Oxygen ions (heavy ions), positive Hydrogen ions (lighter ions), hot electrons from solar origin and colder electrons from cometary origin. The positive Hydrogen ion and the two types of electrons obey \(q\)-non-extensive distributions. The derived equations have three types of ion acoustic waves, which are soliton waves, shock waves and kink waves. The effects of the non-extensive parameters for the hot electrons, the colder electrons and the Hydrogen ions on the propagation of the envelope waves are studied. The compressive and rarefactive shapes of the three envelope waves appear in this system for the first order of the power of the nonlinearity strength with different values of non-extensive parameters. For the second order, the strength of nonlinearity will increase and the compressive type of the envelope wave only appears.     

A combined method for the hydrodynamic characteristics of planing crafts

The prediction of the total resistance of planing crafts at high speeds is very important. In this paper, a combined method is investigated for determining the hydrodynamic characteristics of planing crafts in the calm water. The study consists of a potential-based boundary element method (BEM) for the induced pressure resistance, the boundary layer theory for the frictional resistance and practical method for the spray resistance. The planing surface is represented by a number of elements with constant velocity potential at each element. The unknown-induced pressure is obtained by using the free surface elevation condition and the Kutta condition at the transom stern. Hydrodynamic-induced resistance and lift are determined by the calculated dynamic pressure distributions. The boundary layer analysis method is based on calculations of the momentum integral equation applied to obtain the frictional resistance. A particular practical approach is introduced to present the region of the upwash geometry for the spray. A numerical program has been developed for the present research and applied to the hull form of the craft. Four different hull forms of Series 62 model 4666 planing craft are presented. It is shown that the present combined method is efficient and the results are in good agreement with the experimental measurements over a wide range of volumetric Froude numbers.     

Sources of the predynastic grinding stones in the hu-semaineh region,upper Egypt,and their cultural context

Grinding stones excavated at the Predynastic site of HG in Upper Egypt were analyzed, and consist of igneous rocks (rhyolite porphyry, basalt, granite) and metamorphic rocks (marble, quartzite). These rocks were brought to the site in Predynastic times (ca. 4000–3000 B. C.) from the Dokkan Volcanics located in the Wadi Hammamat, possibly as far away as 150 km. This is further evidence for the widespread exchange network that existed in Predynastic Upper Egypt. Complex economic interaction, as evidenced by artifacts excavated at HG, was a prime force as the early state evolved in Egypt. © 1993 John Wiley & Sons, Inc.     

Magmatic and post-magmatic evolution of post-collisional rare-metal bearing granite: The Neoproterozoic Homrit Akarem Granitic Intrusion,south Eastern Desert of Egypt,Arabian-Nubian Shield

The Homrit Akarem granitic intrusion (HAGI) outcrops near the western edge of the south Eastern Desert basement exposure in Egypt. It is a composite of two cogenetic intrusive bodies: an early albite granite phase shallowly emplaced at the apex of a magmatic cupola, and a later subjacent pink granite phase with a marginal zone of muscovite granite and better preservation of magmatic features. Mineral chemistry of primary biotite and garnet, together with whole-rock chemistry, identify the HAGI as a highly fractionated A-type peraluminous intrusion. The chemistry of F-dominant, Li-bearing, Fe³⁺-rich primary magmatic mica in the pink granite resembles that typically found in highly evolved Nb-Y-F pegmatites. The HAGI is the evolved product of a primary magma generated by partial melting of juvenile crust of the Arabian-Nubian Shield (ANS), emplaced along a regional strike-slip fault system that promoted its ascent. The main emplacement mechanism and evolutionary sequence of the HAGI was magmatic, although secondary minerals and textures resulting from hydrothermal fluid interactions are observed, especially at its margins. Primary columbite-(Mn) crystallized from melt and was partly replaced by secondary fluorcalciomicrolite. The high fluorine content of magmatic fluids exsolved from the intrusion is indicated by quartz-fluorite veins, greisenization, albitization, and F-bearing secondary oxide minerals. The magmatic derivation of this fluid is demonstrated by the F-dominant primary mica, a siderophyllite-polylithionite solid solution commonly known as zinnwaldite. The chemistry of zinnwaldite constrains the F/OH activity ratio and oxygen fugacity of its parental melt and thereby resolves the ambiguity between pressure and the effects of F in controlling the normative quartz content of rare-metal granites. The HAGI is less mineralized than the post-collisional rare-metal granites found further east in the south Eastern Desert, replicating a trend observed previously in the central Eastern Desert and suggesting that east-west zoning in rare metal enrichment is a persistent feature across latitudes at the western edge of the ANS.