ESTIMATION OF ERRORS IN ABSORBANCE RATIO MEASUREMENTS

Ratio measurements are commonly used to address a variety of analytical problems in environmental,forensic and pharmaceutical laboratories.In absorbance ratioing techniques,analytical chemists rely onthe spectral features of the analyte(s)of interest.The absorbances at two wavelengths are monitored andthe ratio of these two absorbances is computed.This ratio is then used to confirm the identity of theanalyte(s)of interest,the purity of a product or the overlap of chromatographic peaks.These decisionsoften have far-reaching consequences(e.g.the identification of the source,biogenic or petrogenic,ofhydrocarbons in biological tissues or water).Given the cost and the liabilities associated with suchdecisions,it is unfortunate that these ratios are seldom reported with any statistical confidence.Thepurpose of this study is to delineate the parameters that affect absorbance ratio measurements.Themodels that can be used to estimate the statistical confidence in these measurements are derived andevaluated experimentally.The results show that these models can estimate the relative standard deviationsin absorbance ratios accurately.They can also estimate the effect of signal-to-noise ratio and the choiceof wavelengths on the precision of absorbance ratios.     

Localized multiscale energy and vorticity analysis: I. Fundamentals

A new methodology, multiscale energy and vorticity analysis (MS-EVA), is developed to investigate the inference of fundamental processes from oceanic or atmospheric data for complex dynamics which are nonlinear, time and space intermittent, and involve multiscale interactions. Based on a localized orthogonal complementary subspace decomposition through the multiscale window transform (MWT), MS-EVA is real problem-oriented and objective in nature. The development begins with an introduction of the concepts of scale and scale window and the decomposition of variables on scale windows. We then derive the evolution equations for multiscale kinetic and available potential energies and enstrophy. The phase oscillation reflected on the horizontal maps from Galilean transformation is removed with a 2D large-scale window synthesis. The resulting energetic terms are analyzed and interpreted. These terms, after being carefully classified, provide four types of processes: transport, transfer, conversion, and dissipation/diffusion. The key to this classification is the transfer–transport separation, which is made possible by looking for a special type of transfer, the so-called perfect transfer. The intricate energy source information involved in perfect transfers is differentiated through an interaction analysis.The transfer, transport, and conversion processes form the basis of dynamical interpretation for GFD problems. They redistribute energy in the phase space, physical space, and space of energy types. These processes are all referred to in a context local in space and time, and therefore can be easily applied to real ocean problems. When the dynamics of interest is on a global or duration scale, MS-EVA is reduced to a classical Reynolds-type energetics formalism.     

Natural Hazards Monitoring:Forest Fires, Droughts And Floods - The Example Of European Pilot Projects

This paper reviews the subject of naturalhazards and the use of existing remote sensing systemsin the different phases of disaster management forsome specific natural hazards: forest fires, droughtsand floods. It centers on the applicability of remotesensing for increasing preparedness, providing earlywarnings, monitoring the hazards in real time, andassessing the damage so that relief can be provided. Comparison of the information provided by existingsystems and that needed for operational use of remotesensing in disaster management is also addressed. Thecapability of some of the future sensors to complywith the needs in the field of natural hazards isdiscussed. In this context current pilot projectscarried on at the European Commission Joint ResearchCentre are presented.     

Hypoxia in Manila Bay, Philippines during the northeast monsoon

Herein we present results from one of the first extensive bay-wide oceanographic surveys of Manila Bay, wherein 31 stations were sampled during the northeast monsoon (cold and dry season). A band of hypoxic bottom water (dissolved oxygen<2.8 mg/L) spanned the midsection of the bay from east to west. Bottom nitrate concentrations (5.7-16.8 μM; avg. 11.1 μM) and total organic carbon values in sediments (1.7-3.1%; avg. 2.4%) were high in the midsection, which coincided with the band of hypoxic bottom water. Physical processes and site-specific accumulation of organic material likely lead to hypoxic conditions in Manila Bay, even during the northeast monsoon period when the water column is relatively well mixed. The results of this study complement the previously reported widespread hypoxia that occurs during the rainy season. Thus, hypoxia may be pervasive in the bay throughout the year, although it varies in intensity and spatial extent.     

Nutrient inputs from submarine groundwater discharge on the Santiago reef flat, Bolinao, Northwestern Philippines

Submarine groundwater discharge (SGD) on the reef flat of Bolinao, Pangasinan (Philippines) was mapped using electrical resistivity, 222Rn, and nutrient concentration measurements. Nitrate levels as high as 126 μM, or 1-2 orders of magnitude higher than ambient concentrations, were measured in some areas of the reef flat. Nutrient fluxes were higher during the wet season (May-October) than the dry season (November-April). Dissolved inorganic nitrogen (DIN=NO3+NO2+NH4) and soluble reactive phosphorus (SRP) fluxes during the wet season were 4.4 and 0.2 mmoles m(-2) d(-1), respectively. With the increase population size and anthropogenic activities in Bolinao, an enhancement of SGD-derived nitrogen levels is likely. This could lead to eutrophic conditions in the otherwise oligotrophic waters surrounding the Santiago reef flat.     

Coupling of the Crustal and upper mantle deformations in the Mongolia-Siberian Mobile Area

The complex analysis of parameters characterizing the modern deformations of the Earth’s crust and upper mantle in the territory of the Mongolia-Siberian Area is made. Directions of principal tension axes of stress-tensors, calculated with the use of earthquake source mechanisms have been taken as parameters of modern deformations at the level of the middle crust; directions of axes of horizontal strains in the geodesic network by the GPS data have been taken as such parameters at the level of the Earth’s surface. The strain parameters for the mantle depths are the data on seismic anisotropy derived from the published sources about the results of studies on splitting of transversal waves from distant earthquakes. Seismic anisotropy is interpreted as the ordered orientation of olivine crystals, which appears with great strains resulting from the flow of the mantle material. It has been shown that directions of extensional strain axes (minimal compression) by geodesic and seismological data coincide with anisotropy directions in the upper mantle in the region whose median value is 310°–320°. The observed mechanical coupling of the crust and the upper mantle of the Mongolia-Siberian Mobile Area shows the participation of the lithospheric mantle in the formation of neotectonical structures and enables us to distinguish the principal processes determining the Late Cenozoic tectogenesis in this territory. One of the leading mechanisms for the neotectonical and modern deformations of the Mongolia-Siberian Region is the large-scale NW-SE material flow in the upper mantle causing both motion of the entire northern part of the continent and divergence of the Eurasia and the Amurian Plate. Lithospheric deformations in the western part of the region are related to collision-induced compression, while those in the central part are caused by interaction of these large-scale tectonic processes.     

Distribution of gold and silver and its relation with hypogene ore minerals in the Esperanza porphyry deposit,Antofagasta Region,Chile

Modes of occurrence of Au‐ and Ag‐bearing phases and their relation with associated hypogene ore minerals were examined with the objective to elucidate Au‐Ag distribution at the Esperanza porphyry deposit in the Eocene Centinela copper belt, using ore‐microscope modal analysis, semi‐quantitative analyses by automated mineralogy, electron probe microanalysis, and secondary ion mass spectrometer. The Esperanza hypogene mineralization is characterized by early‐stage chalcopyrite‐rich veinlets in the potassic alteration zone and later polymetallic stage with tennantite and galena in the chlorite‐sericitic alteration zone. Only the early‐stage chalcopyrite contains fine‐grained electrum (Au₆₈Ag₃₂ ‐ Au₈₁Ag₁₉) and hessite (Ag₂Te), and thus yields positive correlations in Cu vs. Au and Cu vs. Ag grades that are clearly recognized in the hypogene sulfide zone. The early‐stage chalcopyrite grains frequently exhibit polysynthetic twinning suggestive of inversion from intermediate solid solution. These features suggest that the fine‐grained electrum and hessite are products exsolved in the cooling process with the intermediate solid solution to chalcopyrite inversion. In contrast, tennantite and galena of the later‐stage mineralization contain no detectable Ag, and it is thus proposed that the early‐stage inverted chalcopyrite is the principal storage of economically important precious metals.     

应用X射线衍射-激光拉曼光谱-电子探针等分析测试技术研究旬阳朱砂玉的矿物学特征

近年来外观形似鸡血石的红色朱砂玉备受关注,其中吉林、贵州、青海等地这种红色岩石已有矿物成分、岩性等相关方面的研究。本文利用常规宝石常数测定手段、偏光显微镜、X射线粉晶衍射仪、激光拉曼光谱仪、电子探针等分析测试技术,对陕西旬阳朱砂玉的矿物学和宝石学特征进行了研究。结果表明,该产地朱砂玉的矿物成分以石英、辰砂为主,含有少量的方解石、白云石、重晶石、黄铁矿;其中主要矿物成分辰砂的颜色随铁含量的增加而逐渐加深;矿物结构以碎屑结构、粒状变晶结构、穿插交代结构为主。根据矿物成分以及矿床成因的研究分析,初步认为陕西旬阳朱砂玉属于沉积-热液-强烈改造型矿床。该地区的朱砂玉与鸡血石的相似之处在于矿物的主要成分都含有辰砂,致使外观品质上具有一定的相似性,但具体矿床成因以及矿物成分有着明显的差别:旬阳朱砂玉产于沉积-热液-强烈改造型矿床中,其“地”主要矿物成分为石英岩,“血”为辰砂;而浙江昌化和内蒙古巴林鸡血石均产于中生代交代蚀变酸性火山岩的次级断裂小构造中,其“地”主要为地开石、高岭石、叶腊石,“血”为辰砂。此次研究采用多种分析测试手段为旬阳朱砂玉与鸡血石的鉴别提供了可靠的依据。     

Soil moisture retrieving using hyperspectral data with the application of wavelet analysis

As a powerful tool, the wavelet transform method has been widely used in feature extraction for hyperspectral data, while few studies are focused on soil moisture retrieving. The objective of this study was to evaluate the effectiveness of discrete wavelet transform (DWT) for soil moisture retrieving. In this study, a total of 78 measurements of soil moisture and hyperspectral data were collected through soil sampling as well as laboratory quantitative control. There were 13 different mother wavelets capable of decomposing hyperspectral data that were recommended, along with six decomposition levels from 5 to 10. The performances of two feature extraction methods namely band selection and DWT were compared, using three indexes, i.e., R ², R _adj and root mean square error (RMSE) introduced to validate soil moisture retrieving results. The experimental results indicated that the wavelet transform method could significantly reduce the dimensionality of hyperspectral data, resulting in a much more effective performance. Among the 78 estimation models using the wavelet transform, there were 42 models superior to band selection, with 24 models yielding good correlations between the predicted soil moisture and the measured ones (R ² ≥ 0.7, RMSE ≤ 0.050, p ≤ 0.05). Furthermore, when the wavelet decomposition level was 9 and the mother wavelets were Daubechies 2, Daubechies 4, Reserve Biorthogonal 3.3 and Biorthogonal 6.8, the retrieving results were optimum. Additionally, the experimental results proved that the wavelet analysis technique was capable of preserving high- and low-frequency spectral information at different decomposition scales, and could correctly reflect the variation of soil moisture. Thus, it would be helpful in further environmental monitoring.