Biological data from sharks landed within the United Arab Emirates artisanal fishery     

RW Jabado  SM Al Ghais  W Hamza  DP Robinson  AC Henderson 《African Journal of Marine Science》2016,38(2):217-232

Landing site and market surveys of sharks landed along the Arabian Gulf coast of the United Arab Emirates were undertaken between October 2010 and September 2012 to obtain biological data from this artisanal fishery. Data were collected on the size and sex of 12 482 individuals representing 30 species. Maximum sizes of Carcharhinus sorrah, C. amblyrhynchoides and Hemipristis elongata were extended by at least 300?mm total length (TL) compared with published global maxima. The size at 50% maturity was determined for males of five species and this indicated that the males of smaller shark species (<1 000 mm maximum TL) in the fishery were largely mature. For many species, including Loxodon macrorhinus and Mustelus mosis, overall sex ratios were male-biased, indicating that sexual segregation is likely in those species. Furthermore, sex ratios for several species, such as Rhizoprionodon acutus, showed differences across seasons. Overall, the landings contained a high proportion of juveniles, causing concerns about the sustainability of this fishery. Biological parameters of a number of species differed from those recorded earlier for the region, demonstrating a need for additional local data collection to support the development of management measures.  相似文献   

Anomalous heat flow belt along the continental margin of Brazil     

Hamza  Valiya M.  Vieira  Fabio P.  Silva  Raquel T. A. 《International Journal of Earth Sciences》2018,107(1):19-33

International Journal of Earth Sciences - A comprehensive analysis of thermal gradient and heat flow data was carried out for sedimentary basins situated in the continental margin of Brazil (CMB)....  相似文献   

Use of Solute Chemistry and Isotopes to Identify Sources of Ground-Water Recharge in the Nile Aquifer System, Upper Egypt     

Mostafa A. Awad  Nahed E. El Arabi  Mokhtar S. Hamza 《Ground water》1997,35(2):223-228

  相似文献   

A neural network approach for attenuation relationships: An application using strong ground motion data from Turkey   总被引：1，自引：0，他引：1  

Hamza Güllü  Ergun Erelebi 《Engineering Geology》2007,93(3-4):65-81

This paper presents an application of neural network approach for the prediction of peak ground acceleration (PGA) using the strong motion data from Turkey, as a soft computing technique to remove uncertainties in attenuation equations. A training algorithm based on the Fletcher–Reeves conjugate gradient back-propagation was developed and employed for three sample sets of strong ground motion. The input variables in the constructed artificial neural network (ANN) model were the magnitude, the source-to-site distance and the site conditions, and the output was the PGA. The generalization capability of ANN algorithms was tested with the same training data. To demonstrate the authenticity of this approach, the network predictions were compared with the ones from regressions for the corresponding attenuation equations. The results indicated that the fitting between the predicted PGA values by the networks and the observed ones yielded high correlation coefficients (R²). In addition, comparisons of the correlations by the ANN and the regression method showed that the ANN approach performed better than the regression. Even though the developed ANN models suffered from optimal configuration about the generalization capability, they can be conservatively used to well understand the influence of input parameters for the PGA predictions.  相似文献   

Surface effect on the isotopic fractionation between CO2 and some carbonate minerals     

M.S. Hamza 《Geochimica et cosmochimica acta》1974,38(5):669-681

The surface effect on the isotopic fractionation between CO₂ and calcite, dolomite and witherite has been studied through gas-solid exchange experiments. Oxygen isotope fractionation between surface calcite and CO₂ was found to be higher by 5–6%. than the fractionation between bulk calcite and CO₂.Similar studies were made using dolomite and witherite. The dolomite-calcite and witheritecalcite fractionation evaluated through the surface exchange with CO₂ were found to be close to values determined by other workers under controlled conditions in the laboratory.  相似文献   

Mixed nonparametric–parametric probabilistic model for earthquake reliability of an inelastic reinforced concrete frame structure     

C. Desceliers  G. Bonnet  S. Hamza  P. Delmotte 《Bulletin of Earthquake Engineering》2010,8(4):921-935

The paper is devoted to the study of uncertainties when studying buildings under seismic loading. These uncertainties are related to the simplifications used when constructing the model (model uncertainties) and to the numerical data needed at the computation stage (data uncertainties). It has been shown in previous papers that nonparametric models are able, in the case of linear dynamics, to deal simultaneously with these two kinds of uncertainties. The paper presents an extension of this kind of model by taking into account a “mixed” approach for concrete frame structures, which uses a nonparametric model for the part of the structure which behaves linearly and a parametric approach for the parts of the structure (plastic hinges) which behave non-linearly. A numerical application is presented in the case of a residential building.  相似文献   

Reply to comments by Henry N. Pollack and David S. Chapman on “Spherical harmonic analysis of Earth’s conductive heat flow”     

V. M. Hamza  R. R. Cardoso  C. F. Ponte Neto 《International Journal of Earth Sciences》2008,97(2):233-239

Pollack and Chapman, hereafter referred to as P&C, argue that: (1) errors arising from lack of quality control in the IHFC database are not important and not properly documented, (2) resolution of spatial patterns in global heat flux distribution should not be represented by spherical harmonics and (3) heat flow in young oceanic crust and global heat loss are better represented by a contested 1-D cooling model than by the data. We disagree and provide additional information that may help clear up such misunderstandings. We also mention briefly the results of a new improved thermal model of the lithosphere that satisfactorily reproduces the main features identified in observational data sets of heat flow and ocean floor bathymetry. Thus, there is no reason to invoke the ad hoc hypothesis of large-scale hydrothermal circulation in the ocean crust.  相似文献   

Preface     

Vladimir Cermak  Valiya M. Hamza 《International Journal of Earth Sciences》2008,97(2):201-203

  相似文献   

Terrestrial heat flow in various parts of India     

R. K. Verma  R. U. M. Rao  M. L. Gupta  G. Venkateshwar Rao  V. M. Hamza 《Bulletin of Volcanology》1969,33(1):69-88

Results of heat flow studies made in different parts of India including Kolar Gold Field, Cuddapah basin, Singhbhum thrust zone, Aravalli mountain system of Precambrian age, Godavary valley of Mesozoic age and Cambay basin of Cenozoic age are discussed. Heat flow has been found to be low in the southern part of the Preambrian shield. Relatively higher values have been obtained along the northeastern (Singhbhum) and the northwestern parts of the shield (Aravallies). High heat flow has been found along the southeastern part of the Godavary valley and the Cambay basin. The correlation of heat flow with geology and tectonic history in the respective areas is discussed.  相似文献   

The relationship of heat flow with age of basement rocks     

V. M. Hamza  R. K. Verma 《Bulletin of Volcanology》1969,33(1):123-152

The relationship of heat flow to age of the basement rocks has been studied for USA and Canada, Australia and India. In areas of sedimentary basins the ages of the cores obtained from the metamorphic or igneous basement were used for such correlation. It is found that heat flow values for all continents studied show a definite correlation with age the relatively high heat flow being associated with younger basements. Such correlation when fully established will enable us to correlate heat flow values with geology and ages of tectonic events which have occurred in the earth’s crust.  相似文献