利用微波辐射计对水淹区和盐渍化土壤制图

水淹和盐度，在海岸地带是两个同等重要的问题，目前还没有一种精确的遥感技术可以用来对受这两个因素影响的地带制图。为了研究采用微波辐射计进行这种制图的可行性，我们通过能够反映水淹区和盐渍区特性的层化模型，进行了亮度温度的数值计算。亮度温度的特性可以显示出水淹区和盐渍区的特征值。本文所提供的结果表明了微波辐射计在对水淹区和盐渍区制图方面的应用价值。     

利用微波遥感估算盐度

土壤水分的相互作用和释放出的了引起水的盐度。河、湖、水海洋和地表水，由于渗秀和和表面耗失而变化。我们通过数值计算的方法对代表河、湖和海洋水特征的各种模的微波呼应进行了分析，研究了用微波遥感估算盐度的可行性。结果表明微波遥感响应特性对盐度和水表温度的依赖关系，研究结果地微波传感器参数的选择以及在微波遥感数据锻算盐度方面是有用的。     

Density of rural population in an Indian situation: a contemporary approach

The spatial patterns in the density of rural population in an area are a function of the complex interplay of physical, economic, social, and technological forces. However, natural forces play a more prominent role than others in this respect. This is especially true of the developing world where application of modern technologies is limited and economies are predominantly agricultural in nature. This paper establishes quantitatively the superiority of the physical environment in effecting spatial patterns in the density of the rural population in Punjab. Only 3 variables taken from natural setup, rainfall, soil, and water, jointly explain over 53% of the spatial variance in the density of the rural population in Punjab. This clearly proves the supremacy of physical forces over others in determining spatial patterns in the density of the rural population in an agricultural area of the developing world. However, the concept needs further testing in some similar areas to establish its validity on a wider scale.     

Travel time to a well pumping an unconfined aquifer without recharge

A solution is given for the travel time to a well pumping an ideal, horizontal unconfined aquifer, under steady-state conditions, when recharge from infiltration is negligible. Three forms of the solution are provided: a closed-form solution, an integral to be calculated in a worksheet, and a simple equation. The three forms of the solution give travel times nearly identical to those obtained using a finite-element code for saturated and unsaturated flow and particle tracking.     

A new method to characterize hydraulic short-circuits in defective borehole seals

A new approach has been developed to detect, characterize, and quantify hydraulic short-circuits in boreholes with faulty seals. The methodology, applicable to an aquifer-aquitard-aquifer system, involves a series of successive, constant-rate pumping tests in the lower aquifer while determining the leakage rate with a simultaneous nonreactive tracer test. During each pumping step, the tracer is injected under constant concentration and constant hydraulic head from a piezometer in the upper aquifer. If a seal defect exists, the tracer will follow the leak and will be recovered from the pumped water. The theoretical equations relate the leakage rate, the pumping rate, the concentration of the injected tracer, and the recovered concentration. Leakage rates can be determined for any pumping rate. The theory is tested using numerical analysis and a full-scale field test.     

Pumping test in a confined aquifer under tidal influence

In a coastal environment, tide-induced head fluctuations can complicate the interpretation of drawdown data from pumping tests. For confined aquifers and sinusoidal tides, the superposition principle can be used to obtain a closed-form solution. After subtracting the net tidal effects, the drawdown data become amenable to the standard analyses. Numerical simulations have shown that the method is reliable when the distance of the monitoring well to the well does not exceed 10% of the distance between the well and the tidal boundary.     

Arsenic species in weathering mine tailings and biogenic solids at the Lava Cap Mine Superfund Site,Nevada City,CA

Background  

A realistic estimation of the health risk of human exposure to solid-phase arsenic (As) derived from historic mining operations is a major challenge to redevelopment of California's famed "Mother Lode" region. Arsenic, a known carcinogen, occurs in multiple solid forms that vary in bioaccessibility. X-ray absorption fine-structure spectroscopy (XAFS) was used to identify and quantify the forms of As in mine wastes and biogenic solids at the Lava Cap Mine Superfund (LCMS) site, a historic "Mother Lode" gold mine. Principal component analysis (PCA) was used to assess variance within water chemistry, solids chemistry, and XAFS spectral datasets. Linear combination, least-squares fits constrained in part by PCA results were then used to quantify arsenic speciation in XAFS spectra of tailings and biogenic solids.     

Remote sensing of coral reefs and their physical environment

There has been a vast improvement in access to remotely sensed data in just a few recent years. This revolution of information is the result of heavy investment in new technology by governments and industry, rapid developments in computing power and storage, and easy dissemination of data over the internet. Today, remotely sensed data are available to virtually anyone with a desktop computer. Here, we review the status of one of the most popular areas of marine remote sensing research: coral reefs. Previous reviews have focused on the ability of remote sensing to map the structure and habitat composition of coral reefs, but have neglected to consider the physical environment in which reefs occur. We provide a holistic review of what can, might, and cannot be mapped using remote sensing at this time. We cover aspects of reef structure and health but also discuss the diversity of physical environmental data such as temperature, winds, solar radiation and water quality. There have been numerous recent advances in the remote sensing of reefs and we hope that this paper enhances awareness of the diverse data sources available, and helps practitioners identify realistic objectives for remote sensing in coral reef areas.     

Investigations into the bioavailability and bioaccumulation of mercury and other trace metals to the sea cucumber, Sclerodactyla briareus, using in vitro solubilization

The in vitro solubilization and bioaccumulation of mercury and other trace metals by the intestinal fluid of the sea cucumber, Sclerodactyla briareus, was investigated. Sediments were incubated with intestinal fluid and the intestinal fluid was analyzed for the in vitro experiments. Experiments examined both procedural effects of in vitro solubilization and bioaccumulation of trace metals by the sea cucumber. Both solubilization and bioaccumulation were compared among the different metals. This comparison revealed that monomethylmercury (MMHg) solubilization and bioaccumulation is greater than Hg_I; Cd solubilization is higher than MMHg and Hg_I; and Cu and Pb solubilization is similar to MMHg and slightly higher than Hg_I. Solubilization and bioaccumulation was found to be very low, except for Cd, which had high relative solubilization but low bioaccumulation. It was concluded that while solubilization could be the rate-limiting step for certain metals, other factors, such as depuration and membrane transport, may influence overall bioaccumulation of the other metals.     

Spatial variation of metal bioaccumulation in the hydrothermal vent mussel Bathymodiolus azoricus

The variability of the bioaccumulation of metals (Ag, Cd, Cu, Fe, Mn and Zn) was extensively studied in the mussel Bathymodiolus azoricus from five hydrothermal vent sites inside three main vent fields of increasing depth along the Mid-Atlantic Ridge: Menez Gwen, Lucky Strike and Rainbow. Metal bioaccumulation varied greatly between vent fields and even between sites inside a vent field with B. azoricus showing a great capacity to accumulate metals. The bioaccumulation of these metals also varied significantly among tissues. The main target was the gills where metals were mainly associated with soluble compounds whereas in the digestive gland they were mainly associated with insoluble compounds. Storage of metals under insoluble forms in B. azoricus seems to be a major pathway for the detoxification of both essential and non-essential metals. Mussels from the studied fields can be discriminated following their metallic load but the segregation relies partially on the composition of the metal-enriched fluids.