Measuring and managing changes in estuaries and lagoons: morphological and eco-toxicological aspects   总被引：1，自引：0，他引：1  

Zonta R  Guerzoni S  Pérez-Ruzafa A  de Jonge VN 《Marine pollution bulletin》2007,55(10-12):403-406

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Distribution of arsenic and mercury in subtropical coastal beachrock,Gulf of Mannar,India   总被引：1，自引：0，他引：1  

J Dajkumar Sahayam  N Chandrasekar  S Krishna Kumar  G Victor Rajamanickam 《Journal of Earth System Science》2010,119(1):129-135

An assessment of coastal pollution was made on the basis of trace element concentrations (arsenic — As, mercury — Hg) in the Gulf of Mannar. The beachrock samples were collected along the coastal tracts between Rameswaram and Kanyakumari. The samples were dried and digested to determine the As and Hg using atomic absorption spectrophotometer (AAS-air-acetylene and nitrous oxide method). The As and Hg accumulation status of the beachrock was assessed using geo-accumulation index values (I _geo). The accumulation of As and Hg in the beachrock ranges from 2.75 to 20.72 μg g⁻¹ and from 0.06 to 0.31 μg g⁻¹, respectively. The As and Hg concentrations in the beachrocks are compared with crustal average values and average of other region sediments. The possible source of the contamination is from atmospheric deposition and anthropogenic activities.  相似文献   

Reply to “Rip Current Misunderstandings”     

Victor A. Gensini  Walker S. Ashley 《Natural Hazards》2010,55(2):163-165

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Phytoplankton diversity in a tropical bay,North Borneo,Malaysia as revealed by light microscopy and Next-Generation Sequencing     

Brian Wei Khong Chong  Sandric Chee Yew Leong  Victor S. Kuwahara  Teruaki Yoshida 《海洋学报(英文版)》2022,41(12):142-151

Assessments of phytoplankton diversity in Sabah waters, North Borneo, have primarily relied on morphology-based identification, which has inherent biases and can be time-consuming. Next-Generation Sequencing (NGS) technology has been shown to be capable of overcoming several limitations of morphology-based methods. Samples were collected from the Sepanggar Bay over the course of the year 2018 in different monsoon seasons. Morphology-based identification and NGS sequencing of the V8–V9 region of the 18S LSU rDNA were used to investigate the diversity of the phytoplankton community. Microscopy and NGS showed complementary results with more diatom taxa detected by microscopy whereas NGS detected smaller and rarer taxa. The harmful algal genera in the study site comprised of Skeletonema, Margalefidinium, Pyrodinium, Takayama, and Alexandrium as detected by NGS. This study showed that that an integrative approach of both morphological and molecular techniques could provide more comprehensive information about the phytoplankton community as the approach captured quantitative variability as well as the diversity of phytoplankton species.  相似文献   

Catchment precipitation processes in the San Francisco valley in southern Ecuador: combined approach using high-resolution radar images and in situ observations     

Andreas Fries  Rütger Rollenbeck  Fabian Bayer  Victor Gonzalez  Fernando Oñate-Valivieso  Thorsten Peters  Jörg Bendix 《Meteorology and Atmospheric Physics》2014,126(1-2):13-29

The precise estimation of precipitation quantities in tropical mountain regions is in great demand by ecological and hydrological studies, due to the heterogeneity of the rainfall distribution and the lack of meteorological station data. This study uses radar images and ground station data to provide the required high-resolution precipitation maps. Also wind data are taken into account, due to its influence on the precipitation formation and to demonstrate the relation between synoptic wind, topography and the precipitation distribution inside small mountain valleys. The study analyses the rainfall distribution and amounts of 4 days inside the San Francisco Valley, a small catchment in the tropical Andes of southern Ecuador, representing different seasons and the typical atmospheric flows, which are correlated to the annual precipitation map. The results show that the rainfall distribution and amounts are generally defined by the wind direction and velocity, besides the topographic location in relation to the main barriers and pathways. The dominant wind direction causes a division of the catchment in a wetter eastern and a dryer western part. Moreover, the annual seasons are reversed; the main rainy season for the eastern part occurs between June and August, while the western part reaches the precipitation maximum between January and March. This may have influence on the species composition at the different slopes and the annual hydrological cycle inside the catchment.  相似文献   

Construction and Efficient Implementation of Adaptive Objective-Based Designs of Experiments     

Léticia Buslig  Jean Baccou  Victor Picheny 《Mathematical Geosciences》2014,46(3):285-313

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Late Cretaceous porphyry copper mineralization in Sonora,Mexico: Implications for the evolution of the Southwest North America porphyry copper province   总被引：1，自引：0，他引：1  

Fernando Barra  Victor A Valencia 《Mineralium Deposita》2014,49(7):879-884

Two porphyry Cu-Mo prospects in northern Sonora, Mexico (Fortuna del Cobre and Los Humos) located within the southwestern North American porphyry province have been dated in order to constrain the timing of crystallization and mineralization of these ore deposits. In Fortuna del Cobre, the pre-mineralization granodiorite porphyry yielded an U-Pb zircon age of 76.5?±?2.3 Ma, whereas two samples from the ore-bearing quartz feldespathic porphyry were dated at 74.6?±?1.3 and 75.0?±?1.4 Ma. Four molybdenite samples from Los Humos porphyry Cu prospect yielded a weighted average Re-Os age of 73.5?±?0.2 Ma, whereas two samples from the ore-bearing quartz monzonite porphyry gave U-Pb zircon ages of 74.4?±?1.1 and 74.5?±?1.3 Ma, showing a Late Cretaceous age for the emplacement of this ore deposit. The results indicate that Laramide porphyry Cu mineralization of Late Cretaceous age is not restricted to northern Arizona as previously thought and provide evidence for the definition of NS trending metallogenic belts that are parallel to the paleo-trench. Porphyry copper mineralization follows the inland migration trend of the magmatic arc as a result of the Farallon slab flattening during the Laramide orogeny.  相似文献   

Calibration of an evapotranspiration model to simulate soil water dynamics in a semiarid rangeland     

M. P. Maneta  S. Schnabel  W. W. Wallender  S. Panday  V. Jetten 《水文研究》2008,22(24):4655-4669

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LEGRI instrument health. A historical review     

Julia Suso  Pere Blay  Almudena Robert  Victor Reglero  Chris J. Eyles 《Astrophysics and Space Science》2001,276(1):299-309

LEGRI has been operating successfully on MINISAT-01 since its switch-on the 22nd of May 1997. HouseKeeping (HK) data have been continuously receivedfor nearly two years by LEGRI SOC in Valencia, and subsequently checked on adaily basis and then stored for long term monitoring analysis.LEGRI HouseKeeping data include three critical operating parameters:temperature, power and polarisation voltages. Six temperature sensors arespread over the different LEGRI units: Detector Unit, Data Processing Unit,High Voltage Unit and Star Sensor. Voltages are measured at eight differentpoints. Detector Unit temperature and polarisation voltage are thecritical parameters for LEGRI operation. Solid state detectors aresensitive to changes not only in polarisation but also in temperature.Around one and a half million of measurements for each of the HK fourteen parameters have been recorded and analysed. The data show a very remarkablestability, within the expected margins, and the averages are very close to theoptimal design values. Special attention has been paid to the detectorpolarisation voltages analysis with a mean value of 286 ± 2 V when the detectors are operating. Thermal control over all the LEGRI units shows a remarkable stability in their temperatures.On the detector plane a mean value of T _det = 13 ± 2 ^°C has been found.We can therefore conclude that LEGRI as a system has been operating withinits optimal design conditions. We also want to point out the excellentperformance of the MINISAT-01 thermal control system.  相似文献   

Activity-composition relations in the system CaCO₃-MgCO₃ predicted from static structure energy calculations and Monte Carlo simulations     

Victor L. Vinograd  Benjamin P. Burton  Neil L. Allan 《Geochimica et cosmochimica acta》2007,71(4):974-983

Thermodynamic mixing properties and subsolidus phase relations of the rhombohedral carbonate system, (1 − x) · CaCO₃ − x · MgCO₃, were modelled in the temperature range of 623-2023 K with static structure energy calculations based on well-parameterised empirical interatomic potentials. Relaxed static structure energies of a large set of randomly varied structures in a 4 × 4 × 1 supercell of calcite (a = 19.952 Å, c = 17.061 Å) were calculated with the General Utility Lattice Program (GULP). These energies were cluster expanded in a basis set of 12 pair-wise effective interactions. Temperature-dependent enthalpies of mixing were calculated by the Monte Carlo method. Free energies of mixing were obtained by thermodynamic integration of the Monte Carlo results. The calculated phase diagram is in good agreement with experimental phase boundaries.  相似文献