(Table 1) Th and U concentrations and activity ratios in deep-sea sediments at ODP Hole 105-646B

The Labrador Sea is a particularly suitable high-latitude basin for investigating U and Th behavior in deep-sea sediments. During the late Quaternary, the cyclic development and decay of huge ice sheets on adjacent land masses resulted in large-amplitude changes in sedimentation rates and organic paleoproductivities. The resulting magnification of U and Th response is well illustrated by high-resolution studies on piston-cored sediments from the Greenland continental rise at Ocean Drilling Program Leg 105 Site 646 spanning isotopic stages 8 to 1. Our results show a clear positive correlation of 238U/232Th ratios with organic paleoproductivity indicators (e.g., dinocyst) due to U uptake in the water column and/or during the early early diagenesis of organic matter responding to carbon fluxes and to their climate forcing. 230Th excesses over 234U exceed the theoretical value of the 230Th rain from the overlying water column, indicating lateral input possibly from the Greenland slope and shelf. Because these horizontal fluxes of 230Th may be partly controlled by physical parameters, 230Th excesses cannot be unequivocally correlated with sedimentation rates and/or productivity as reported elsewhere. In this subarctic basin characterized by low overall organic carbon burial, the 238U/232Th ratio appears to be a sensible geochemical indicator of organic activity and paleoproductivity.

The Taiwan Strait Crisis of 1954-55 and U.S.-R.O.C Relations

On September 3, 1954, Chinese artillery began shelling Quemoy (Jinmen), one of the Kuomintang-held offshore islands, setting off the first Taiwan Strait Crisis. This paper focuses on the crisis and analyzes the following three questions: (1) What was the policy the U.S. took towards the Republic of China (R.O.C), especially towards the offshore islands, to try to end the Taiwan Strait Crisis? (2) What were the intentions of the U.S. government in trying to end the Taiwan Strait Crisis? And (3) how should U.S. policy towards the R.O.C. which led to solving the Taiwan Strait Crisis be positioned in the history of Sino-American relations? Through analysis of these questions, this study concludes that the position the U.S. took to bring an end to crisis, one which prevented China from “liberating Taiwan” and the Kuomintang from “attacking the mainland,” brought about the existence of a de facto “two-China” situation.

Climate Change Impacts on Maize and Dry Bean Yields of smallholder farmers in Honduras

The rotation maize and dry bean provides the main food supply of smallholder farmers in Honduras. Crop model assessment of climate change impacts (2070?2099 compared to a 1961?1990 baseline) on a maize?dry bean rotation for several sites across a range of climatic zones and elevations in Honduras. Low productivity systems, together with an uncertain future climate, pose a high level of risk for food security. The cropping systems simulation dynamic model CropSyst was calibrated and validated upon field trail site at Zamorano, then run with baseline and future climate scenarios based upon general circulation models (GCM) and the ClimGen synthetic daily weather generator. Results indicate large uncertainty in crop production from various GCM simulations and future emissions scenarios, but generally reduced yields at low elevations by 0 % to 22 % in suitable areas for crop production and increased yield at the cooler, on the hillsides, where farming needs to reduce soil erosion with conservation techniques. Further studies are needed to investigate strategies to reduce impacts and to explore adaptation tactics.

Genetically Engineered Crops: A Study of Major Environmental Implications and U.S. Policy

The adoption of genetically modified crops is becoming evermore common in United States agriculture. However, this relatively new technology carries a negative stigma and perceived risks that have resulted commonly in public disapproval. In the United States, bioengineered crops are highly regulated. The significance of environmental benefits such as decreased chemical impact, increased soil conservation, heightened carbon sequestration, decreased energy demands, and reduced air emissions, are important enough to warrant a revision to U.S. policy. The U.S. policy structure needs to be simplified and made more efficient to better facilitate the speed with which new GE products can, and should, be developed while still providing adequate mitigation of potential environmental risks such as species invasiveness and impacts on non-target species.

Clearing and staining skeletons of small vertebrates / by D. Dwight Davis -- and U. R. Gore ; Wilfred H. Osgood --, editor.

no.4(1936)