Comparative urbanization project for the Asian pacific region

This short article outlines the objectives, organization, research frame and content areas of a comparative urbanization project which will start in 1981. The project involves a total of nine national teams each of which is composed of three or more experts from the fields of urban geography, city and regional planning, demography, development economics and other related disciplines. One unique feature of the project is that each of the countries covered will be researched on by its own local researchers. And, the organizer tries to get at least one government official involved, in his personal capacity, as a team member, to get better insight and interpretation of official policies and objectives regarding urbanization. The responsible persons of the national teams and the time table of the project have also been included in this article.     

Alpha emitters in a coral from Bikini lagoon: A testimony to nuclear blasts in the Western Pacific

In the years between 1946 and 1958, Bikini Atoll was the site of a series of nuclear device tests which led to the contamination of the calcium-carbonate tests of organisms, including those of corals. Alpha emitters and other radio-nuclides concentrated in these tests. The purpose of our study was to determine where in these test-alpha-emitters concentrated.Petrography of ultra thin sections, in conjunction with solid state alpha-track detectors, shows that it is possible to assign the alpha activity to different parts of the fabric within a coral. The application of this technique to a coral,Favites virens, from the lagoon of Bikini Atoll showed that the theca, septa and dissepiments of the coral skeleton contain very low concentrations of alpha emitters. By contrast, high concentration of alpha emitters occur in damaged parts of the coral. Some of these damaged areas contain cryptocrystalline calcium carbonate, different organisms (algae and/or bryozoan-like tests) and skeletal debris. High concentrations of alpha emitters are associated with the cryptocrystalline calcium carbonate (up to 3000 pCi/g), the skeletal debris (up to 550 pCi/g), bryozoan-like material, and algae (up to 700 pCi/g).

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Fallout radionuclides in the Pacific Ocean: Vertical and horizontal distributions,largely from GEOSECS stations

From GEOSECS stations, largely, the 1974 distributions of Pu and of¹³⁷Cs are described in the Pacific Ocean north of about 20°S latitude. Changes in some of these distributions are described from 1978 cruises by the authors.The Pacific exhibited, everywhere, a shallow subsurface layer of Pu-rich water with its concentration maximum at about 465 m in 1974; over a large portion of the central North Pacific a second layer of Pu-labelled water, less concentrated than the shallow layer, lay just above the bottom. Similar features were not observed in the case of¹³⁷Cs.The inventories of both Pu and¹³⁷Cs in the water column at most 1974 stations are substantially greater than those to be expected from world-wide fallout alone; these inventory excesses appear to be attributable to close-in fallout, but only if the ratio Pu/¹³⁷Cs in this source was much higher than in world-wide fallout. The North Pacific mean ratio of the inventories is 2.2 times that observed in world-wide fallout.Resolubilization of Pu both from sinking particles and from sediments explains peculiarities of its depth distributions.There is little evidence for tracer movement by sliding downward along density surfaces;¹³⁷Cs appears to have moved to depth by downmixing at the edge of the Kuroshio, and then moved horizontally and upward alongσ_t contours. The shallow Pu-rich layer shows no coordination with density, salinity or O₂ isopleths. The deep Pu-rich layer is restricted to a narrow range of O₂ concentrations that confirm its origin in the Aleutian Trench and rapid spread southward and laterally. Near-bottom circulation processes have been much more active than here-to-fore described.     

Urban geology of boulder,colorado: A progress report

A cooperative program in urban geology between the city of Boulder, Colorado, and the Department of Geological Sciences, University of Colorado, has been in effect since late 1969. The principal geological problems in the rapidly growing urban environment of Boulder include:

1. Swelling clays in the Pierre Shale have been related to foundation failure, pavement heaving, and landsliding on hillslopes.
2. Colluvium and ancient landslides have been made unstable by removal of support, by loading with buildings or fill, and by increases over natural moisture contents through lawn watering and septic-tank seepage.
3. Flooding on high-gradient mountain streams has been caused by sedimentation induced by the constriction of natural channels through urban development. In May, 1969, Bear Canyon Creek overflowed its banks with a discharge of less than one-fifth its design capacity. Flooding was caused by coarse bedload deposited upstream from a culvert.

The Boulder city geologist collects data on soils exposed in open excavations within the city, maps ancient and modern landslides, provides information for contractors bidding on public works projects, and reviews the geologic aspects of all consulting work prepared for the city. Examples of formats used for the communication of information to responsible city officials include geotechnic maps of all open cuts, street pavement design maps, and input into the city-wide standard specifications for enginnering projects.     

Spatial variability of soil nutrients in disturbed riverine mangrove forests at different stages of regeneration in the San Juan River estuary,Venezuela

Geostatistical analysis of selected soil properties were performed in two mangrove sites (B7 and B9) dominated by the mangrove speciesRhizophora mangle along the San Juan River, Venezuela, to evaluate the effect of forest disturbance on nutrient spatial distributions. Plots within area B7 were clear-cut in 1972–1973 and in area B9 in 1982–1983. Four plots within each area were systematically selected and represented natural (2) and regenerated (2) forests. Individual plots were 1.5 ha in B7 and 1.25 ha in B9 and sampled at a resolution of 25 m. Soil samples were obtained at the intersection of an aligned grid with 90 points in B7 and 78 points in B9. Measured soil properties included salinity, total nitrogen, total carbon, total phosphorus, osmolality, and pore water cation concentrations (potassium, calcium, magnesium, and sodium). Sites were sampled in May 1996 and 1997, although spatial analysis was performed only for the data obtained in May 1997. Geostatistical analysis showed that most of the variables tested were spatially auto-correlated within each area and that there were no differences between regenerated and natural plots. Structural variance as a proportion of sample variance ranged from 55–99% for most of the properties. The significant spatial dependence observed for most of the variables in natural and regenerated plots, despite management schedules, indicates that clear-cutting did not have an effect on modifying the distribution of nutrient concentrations. These results suggest that after 15 and 25 yr following forest disturbance nutrient distributions were reestablished either there was not a net effect on patterns of element loss or tidal input was stronger than plant modifications of soils.     

Reducing hypoxia in the Gulf of Mexico: Advice from three models

Summer hypoxia in the bottom waters of the northern Gulf of Mexico has received considerable scientific and policy attention because of potential ecological and economic impacts from this very large zone of low oxygen and because of the implications for management within the massive Mississippi River watershed. An assessment of its causes and consequences concluded that the almost 3-fold increase in nitrogen load to the Gulf is the primary external driver stimulating the increase in hypoxia since the middle of the last century. Results from three very different models are compared to reach the consensus that large-sclae hypoxia likely did not start in the Gulf of Mexico until the mid-1970s and that the 30% nitrogen load reduction called for in an Action Plant to reduce hypoxia, agreed to by a federal, state, and tribal task force, may not be sufficient to reach the plan’s goal. Caution is also raised for setting resource management goals without considering the long-term consequences of climate variability and change.     

On the period variability of GP andromedae

The present paper deals with the pulsation period variability of the high-amplitude δ Scuti star GP Andromedae using a data set covering a time base of 26.9 years. The possibility of a periodic component (reflecting the light-time effect induced by a hypothetic binarity) in the O-C curve is inferred. The presence of this periodicity in the period variation of GP And leads to a diminution of the discrepancy between predicted and observed relative period change rates. The hypothesis of the existence of an unseen companion is discussed. The statistical analysis of the final O-C residuals distribution, indicates their normal or close to normal character. This revised version was published online in July 2006 with corrections to the Cover Date.     

Stability Analysis of the Climate-Vegetation System in the Northern High Latitudes

The stability of the climate-vegetation system in the northern high latitudesis analysed with three climate system models of different complexity: A comprehensive 3-dimensional model of the climate system, GENESIS-IBIS, and two Earth system models of intermediate complexity (EMICs), CLIMBER-2 andMoBidiC. The biogeophysical feedback in the latitudinal belt 60–70° N, although positive, is not strong enough to support multiple steady states: A unique equilibriumin the climate-vegetation system is simulated by all the models on a zonal scale for present-day climate and doubled CO₂ climate.EMIC simulations with decreased insolation also reveal a unique steady state. However, the climate sensitivity to tree cover, T_F, exhibits non-linear behaviour within the models. For GENESIS-IBIS and CLIMBER-2, T_F islower for doubled CO₂ climate than for present-day climate due to a shorter snow season and increased relative significance ofthe hydrological effect of forest cover. For the EMICs, T_F is higher for low tree fraction than for high treefraction, mainly due to a time shift in spring snow melt in response to changes in tree cover. The climate sensitivity to tree coveris reduced when thermohaline circulation feedbacks are accounted for in the EMIC simulations. Simpler parameterizations of oceanic processes have opposite effects on T_F: T_F is lower in simulations with fixed SSTs and higher in simulations with mixed layer oceans. Experiments with transient CO₂ forcing show climate and vegetation not in equilibrium in the northern high latitudes at the end of the 20thcentury. The delayed response of vegetation and accelerated global warming lead to rather abrupt changes in northern vegetation cover in the first halfof the 21st century, when vegetation cover changes at double the present day rate.     

The effect of fault relay and clay smearing on groundwater flow patterns in the Lower Rhine Embayment

Faults strongly impact groundwater flow in the unconsolidated sediments of the Lower Rhine Embayment. Hydraulic head maps show that many individual faults form a barrier to fluid flow whereas relay structures in these faults are sites of hydraulic contact between otherwise separated aquifers. The fluid flow patterns around the Rurrand Fault close to the largest open‐pit mine in the Lower Rhine Embayment is one of the first well‐documented examples of fluid flow around a fault relay zone. The effect of clay smearing could be quantified using the Shale Gouge Ratio (SGR) method that is common in hydrocarbon‐related studies but has not been applied to groundwater flow data so far. The effect of fault relay zones on groundwater flow is analysed using numerical simulations. It is concluded that fault relay needs special consideration in the evaluation of the sealing capacities of faults in sedimentary basins. Moreover, it is demonstrated that the SGR methodology is a promising tool for the estimation of fault zone hydraulic properties in hydrogeological modelling.