Interpretation of Aeromagnetic Data of Part of Gwagwalada Abuja Nigeria for Potential Mineral Targets

This study analyzes aeromagnetic data over a section of Gwagwalada in Abuja. The data were obtained from the Nigerian Geological Survey Agency acquired at 100 m terrain clearance. The study area spans longitudes 7.0875 E to 7.1458 E and latitude 8.9625 N to 9.0 N (about 27 km2). The dataset was reduced to the equator (RTE) and downward continued by 50 m. Analytic signal filter was applied on TMI-RTE grid to detect the edges of the magnetic bodies present. The structure was observed to trend NE-SW. The CET lineament map reveals intersections such as junctions and corners on the map. This revealed structure liable for potential mineralization zone. Euler deconvolution technique applied over the transformed dataset ascertain the location and depth of the structure,having a maximum depth of about 421 m and a minimum of about 59 m.Variation in magnetic depth and susceptibility contrast is specified by the gridded SPI depth map

Phenomenology of the General NMSSM with Gauge Mediated Supersymmetry Breaking

We investigate various classes of Gauge Mediated Supersymmetry Breaking models and show that the Next-to-Minimal Supersymmetric Standard Model can solve the mu-problem in a phenomenologically acceptable way. These models include scenarios with singlet tadpole terms, which are phenomenologically viable, e.g., in the presence of a small Yukawa coupling <~ 10^{-5}. Scenarios with suppressed trilinear A-terms at the messenger scale lead naturally to light CP-odd scalars, which play the r\^ole of pseudo R-axions. A wide range of parameters of such models satisfies LEP constraints, with CP-even Higgs scalars below 114 GeV decaying dominantly into a pair of CP-odd scalars.Comment: 24 pages, 6 figures, typos corrected, reference adde

Structural Exploration of Aeromagnetic Data over Part of Gwagwalada, Abuja for Potential Mineral Targets Using Derivatives Filters

Aeromagnetic data are consistently used for economic interest targeting and geological mapping. Besides solving problems that are concerned with the basement, the method has become a useful tool in exploring minerals,hydrocarbons occurrence,groundwater investigations, and geothermal potentials. This study analyses aeromagnetic data from the Nigerian Geological Survey Agency acquired at 100 m terrain clearance over a section of Gwagwalada in Abuja. The study area spans longitudes 7.0875° E to 7.1458° E and latitude 8.9625° N to 9.0° N (about 27 km2 ). After a reduction to the equator (RTE) transformation, the data is downward continued by 50 m. Different filters are applied to outline area of alteration associated to mineral deposit. Regional geologic structures trend NE - SW.The application of vertical derivatives (FVD and SVD) to the RTE grid enhanced shallow structures which trend NE - SW. Horizontal gradients along the X- and Y- directions enhance geological contacts attributable to blind faults. The Tilt derivative (TD) accentuated fault lines which trend NE - SW

Seasonal variations in phytoplankton composition and biomass in a small lowland river-lake system (Melen River, Turkey)

WOS: 000294698400012A series of studies were carried out to determine the succession and phytoplankton community of the Melen River in the Western Black Sea region of Turkey. The study was conducted at 6 stations at monthly intervals between May 2003 and April 2004. It was observed that the abundance and biovolume of phytoplankton were low in winter, though higher values were recorded in late spring and summer. Among the values noted, the spring peak was 534.38 x 10(5) ind. L-1 and 7384.8 mm(3) L-1 belonging to Peridinium sp. The most common diatom, Cyclostephanos dubius, was favoured by low discharge at stations 1 and 2 in the early summer (214.29 x 10(5) in L-1 and 9.84 x 10(5) in L-1), respectively. Chlorophyll-a concentrations were between 0.86 and 64.2 mu g L-1. A total of 135 taxa belonging to Cyanophyta, Bacillariophyta, Chlorophyta, Dinophyta, Euglenophyta, Heterokontophyta, Streptophyta, and Xanthophyta were identified. The total biomass of the stations 1 and 2 was mainly characterised by Dinophyta and at other stations by Bacillariophyta. Five major genera (Peridinium, Ceratium, Phacus, Cyclostephanos, and Melosira) accounted for over 70% of the total phytoplankton abundance. Phytoplankton abundance was significant and positively correlated with Chl-a and temperature (r = 0.57 and r = 0.78, respectively P < 0.05). Species richness and diversity indices increased gradually throughout the course of the river.Gazi University, Scientific Projects Research ManagementGazi UniversityWe would like to thank Gazi University, Scientific Projects Research Management for financing this research and also the General Directorate of State Hydraulic Works (DSI) for analysing the physical and chemical parameters of the Melen River

A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/), an open source, community-developed astrophysical analysis and visualization toolkit. Analysis and visualization with yt are oriented around physically relevant quantities rather than quantities native to astrophysical simulation codes. While originally designed for handling Enzo's structure adaptive mesh refinement (AMR) data, yt has been extended to work with several different simulation methods and simulation codes including Orion, RAMSES, and FLASH. We report on its methods for reading, handling, and visualizing data, including projections, multivariate volume rendering, multi-dimensional histograms, halo finding, light cone generation and topologically-connected isocontour identification. Furthermore, we discuss the underlying algorithms yt uses for processing and visualizing data, and its mechanisms for parallelization of analysis tasks.Comment: 18 pages, 6 figures, emulateapj format. Resubmitted to Astrophysical Journal Supplement Series with revisions from referee. yt can be found at http://yt.enzotools.org

Stabilized Singlets in Supergravity as a Source of the mu-parameter

Within the context of supergravity-coupled supersymmetry, fields which are gauge and global singlets are usually considered anathema. Their vacuum expectation values are shifted by quadratically divergent tadpole diagrams which are cutoff at the Planck scale, destabilizing the classical potential and driving the singlet field to large values. We demonstrate a new and generic mechanism which stabilizes the singlet in the presence of an extended gauge symmetry. Such a symmetry will be broken down to the Standard Model by the supergravity interactions near the scale of spontaneous supersymmetry-breaking in the hidden-sector (about 10^{10-11} GeV). The resulting singlet expectation value is stabilized and naturally of order the gravitino mass, providing therefore a weak-scale mass for the Higgs fields of the supersymmetric Standard Model (a "mu-parameter"). The resulting low-energy theory is the minimal supersymmetric Standard Model, with all new fields decoupling at the intermediate scale.Comment: 9 pages, LaTe

Regional travel-time residual studies and station correction from 1-D velocity models for some stations around Peninsular Malaysia and Singapore

We have investigated the average P-wave travel-time residuals for some stations around Southern Thailand, Peninsular Malaysia and Singapore at regional distances. Six years (January, 2010–December, 2015) record of events from central and northern Sumatra was obtained from the digital seismic archives of Integrated Research Institute for Seismology (IRIS). The criteria used for the data selection are designed to be above the magnitude of mb 4.5, depth less than 200 km and an epicentral distance shorter than 1000 km. Within this window a total number of 152 earthquakes were obtained. Furthermore, data were filtered based on the clarity of the seismic phases that are manually picked. A total of 1088 P-wave arrivals and 962 S-wave arrivals were hand-picked from 10 seismic stations around the Peninsula. Three stations IPM, KUM, and KOM from Peninsular Malaysia, four stations BTDF, NTU, BESC and KAPK from Singapore and three stations SURA, SRIT and SKLT located in the southern part of Thailand are used. Station NTU was chosen as the Ref. station because it recorded the large number of events. Travel-times were calculated using three 1-D models (Preliminary Ref. Earth Model PREM (Dziewonski and Anderson, 1981, IASP91, and Lienert et al., 1986) and an adopted two-point ray tracing algorithm. For the three models, we corroborate our calculated travel-times with the results from the use of TAUP travel-time calculation software. Relative to station NTU, our results show that the average P wave travel-time residual for PREM model ranges from −0.16 to 0.45 s for BESC and IPM respectively. For IASP91 model, the average residual ranges from −0.25 to 0.24 s for SRIT and SKLT respectively, and ranges from −0.22 to 0.30 s for KAPK and IPM respectively for Lienert et al. (1986) model. Generally, most stations have slightly positive residuals relative to station NTU. These corrections reflect the difference between actual and estimated model velocities along ray paths to stations and can compensate for heterogeneous velocity structure near individual stations. The computed average travel-time residuals can reduce errors attributable to station correction in the inversion of hypocentral parameters around the Peninsula. Due to the heterogeneity occasioned by the numerous fault systems, a better 1-D velocity model for the Peninsula is desired for more reliable hypocentral inversion and other seismic investigations

Assessment of Geologic Controls of Flooding in Parts of OBIO/AKPOR L.G.A., Rivers State, Nigeria

Flooding of Municipal areas is a frequent environmental occurrence in Rivers State that occurs when rainfall runoff meets land surfaces with low water absorbing capacity or when it overwhelms drainage channels. In order to assess the flood situation in the study area, an integrated method which involves field-measurement, geographic information system (GIS),laboratory analysis of soil samples and topographic studies were employed.Digital elevation model of the study area reveals that the flooded areas are situated in areas with elevations lower than its surrounding, thereby acting as a natural basin to retain flood waters after rainfall.Four holes were drilled to depth of 3 m to obtain soil samples at 1 m sampling interval, from which laboratory analysis was carried out to determine some geotechnical parameters such as soil’s particle size, specific gravity, bulk density,porosity,moisture content, permeability and hydraulic conductivity. Results of the analysis show that permeability,hydraulic conductivity and porosity diminishes with respect to depth. The soil in the flooded areas have high fines content (silt and clay), high bulk density which increase with depth and a specific gravity that is typical of organic rich soils that contain sand mixed with a considerable amount of fines. At Nkpolu, mean permeability rates of 0.003 cm/sec, 0.009 cm/sec and 0.033 cm/sec were obtained at 1, 2 and 3 m respectively. At Eneka, mean permeability rates of 0.011 cm/sec,0.018 cm/sec and 0.014 cm/sec were obtained at 1, 2 and 3m respectively,while at Rukpokwu, mean Permeability rates of 0.021 cm/sec was obtained at 1 m, while 0.006 cm/sec was obtained at 2 and 3 m respectively. The mean hydraulic conductivity for the locations under study is of the order of 10-4 ft/day. This study has shown that the flooded areas are located in low lying urban areas which act as basins, therefore, the top soil is crusted with highly compacted soil horizons beneath. With high and frequent rainfall in the region which generates a lot of runoff, in addition to poor drainage system, flooding in the study area occurs frequently.Therefore,construction and maintenance of efficient drainage channels for an effective solution to urban pluvial flooding in the study area are thereby recommended