Single fallout particles and zirconium-95 from the Chinese nuclear explosion of 9 May 1966

Daily fluctuations of the number of single fallout particles and activity of zirconium-95 in the groundlevel air were measured at Fayetteville (94 degrees W, 36 degrees N), Arkansas, for a period of about 3 months after the Chinese nuclear explosion of 9 May 1966. We found a cyclic pattern of variations for both zirconium-95 and fallout particles; this indicated that they were airborne for a long period and traveled far. Apparently, some of the particles circled the world more than once.     

Childhood leukemia and fallout from the Nevada nuclear tests

Cancer mortality data from the National Center for Health Statistics, covering the period 1950 through 1978, were used to test a reported association between childhood leukemia and exposure to radioactive fallout from nuclear weapons tests in Nevada between 1951 and 1958. No pattern of temporal and geographic variation in risk supportive of the reported association was found. Comparison of these results with those presented in support of an association of risk with fallout suggests that the purported association merely reflects an anomalously low leukemia rate in southern Utah during the period 1944 to 1949.     

Fluoride distribution and biological availability in the fallout from mount st. Helens, 18 to 21 may 1980

Concentrations of fluoride in the ash fallout in central Washington from the 18 May 1980 eruption of Mount St. Helens varied severalfold, but none are high enough to constitute any immediate hazard to animal life. The heaviest fallout (Moses Lake) contained 113 parts per million (ppm) of acid-labile fluoride, but of this only 11 ppm was water-soluble and 20 ppm was available to rats. The fluoride concentrations in the urine of cattle feeding for 4 days on hay contaminated with this ash were essentially normal. Samples of ash from other areas generally had higher concentrations of acid-labile fluoride but lower concentrations of water-soluble fluoride. The concentration of water-soluble fluoride was inversely correlated with the coarseness of the fallout.     

Fallout from the Chinese nuclear explosion of 17 June 1967

Low-level activities of iodine-131, barium-140, and strontium-89 were found in a series of rain samples collected at Fayetteville, Arkansas, during the period from late June through August 1967. The ratios of these short-lived isotopes to strontium-90 were determined as accurately as possible. The data indicate that the debris from the Chinese nuclear explosion was injected primarily into the stratosphere.     

Interhemispheric transport of atmospheric fission debris from French nuclear tests

Radioactive iodine-131 (half-life, 8.06 days) and barium-140 (half-life, 12.8 days), released into the atmosphere (21 degrees S, 137 degrees W) by the French nuclear tests conducted during the period 24 August to 8 September 1968, have been observed in rainfall at Arkadelphia, Arkansas (34 degrees N, 94 degrees W). The maximum time required for the transport of the debris from a mid-southern to a mid-northern latitude appears to be about 3 weeks.     

Avian uptake of fission products from an area contaminated by low-level atomic wastes

Birds living on the Oak Ridge White Oak Lake bed, an area contaminated by low-level atomic wastes, revealed a striking seasonal difference in uptake of fission products. Because the omnivorous diet of passerine birds is ecologically comparable to the mixed diet of man, uptake of radionuclides by wild birds provides an assay of amounts to be expected at the trophic level of primary interest to man.     

Ability of some Black Sea organisms to accumulate fission products

The coefficients of accumulation of strontium-90, cesium-137, and cerium-144 in seaweeds, eelgrass, actinia, mollusks, and crustaceans are presented. The discharge of strontium-90 into sea water from decomposing seaweed and the retention and additional absorption of cesium-137 and cerium-144 onto organic debris is discussed. Some observations are made about the ability of these elements to diffuse into sea water and about the relative hazard to man from strontium-90 and cerium-144 in marine life.     

Air-sea waves from the explosion of krakatoa

The distant sea disturbances which followed the explosion of Krakatoa are correlated with recently discovered atmospheric acoustic and gravity modes having the same phase velocity as long waves on the ocean. The atmospheric waves jumped over the land barriers and reexcited the sea waves with amplitudes exceeding the hydrostatic values. An explosion of 100 to 150 megatons would be required to duplicate the Krakatoa atmosphericpressure pulse.     

Epidemiology. Tracking the human fallout from 'mad cow disease'

A task force here has been studying cases of variant Creutzfeldt-Jakob disease (vCJD), an incurable malady of the brain and nervous system that has been linked to eating beef or other products from cattle infected with bovine spongiform encephalopathy or "mad cow disease." The team's goal is to find out just how the patients got infected and how many of them there may ultimately be. The number of confirmed or probable vCJD cases in the United Kingdom is still relatively small--a total of 80 as Science went to press--and recent estimates of the number of potential cases are lower than was once feared. Yet the task force's own recent results show that the incidence of vCJD is rising, and researchers remain determined to try to solve the riddles posed by vCJD.     

Transmutation products may influence radiotracer diffusion rates in an ionic solid

An inherent aspect of radiotracer diffusion is that alpha, beta(+), or beta(-) emission produces a daughter element of different ionization state. This process must either cause a change in the vacancy concentrations or create space charge, depending on the effectiveness of the internal sources or sinks. Four coupled equations established to model the kinetics, when solved by numerical methods, predict that the apparent tracer diffusion rate may easily be in error by a factor of 2 or 3 and, under certain conditions, by as much as an order of magnitude.     

Shock and thermal metamorphism of basalt by nuclear explosion, nevada test site

Olivine trachybasalt metamorphosed by nuclear explosion is classified into categories of progressive metamorphism: (i) Weak. Plagioclase is microfracruree, and augite contains twin lamellae. (ii) Moderate. Plagioclase is converted to glass, amd mafic minerals show intragranular deformation (undulatory extinction, twin lamellae, and, possibly, defomation lamellae), but rock texture is preserved. (iii) Moderately strong. Plagioclase glass shows small-scale flow, mafic minerals are fractured and show intragranular deformation, and rocks contain tension fractures. (iv) Strong. Plagioclase glass is vesicular, augite is minutely fractured, and olivine is coarsely fragmented, shows moscaic extinction, distinctive lamellar structures, and is locally recrystallized. (v) Intense. Rocks are converted to inhomogeneous basaltic glass.     

Black magnetic spherule fallout in the eastern gulf of Mexico

Large numbers of black metallic spherules ranging in diameter from a few micrometers to over 800 micrometers are raining into the eastern Gulf of Mexico and adjacent areas of western Florida. The composition of the flux, its association with glass spherules and coky particles, and its magnitude point to industrial pollution, probably coal- and coke-burning facilities around the perimeter of the gulf, as the source. Since metallic particles represent only a small fraction of most fly ash, such an influx of large numbers of black magnetic spherules must be symptomatic of a much higher rate of sedimentation of fly ash. The internal microstructures and the general appearance of spherules derived from industrial processes are similar to those of particles derived from cosmic sources. Because of the high potential for contamination in micrometeorite studies, a complete compositional verification of each "cosmic" particle may be necessary.     

Abyssal water carbon-14 distribution and the age of the world oceans

The carbon-14 distribution in the abyssal waters of the world oceans indicates replacement times for Pacific, Indian, and Atlantic ocean deep waters (more than 1500 meters deep) of approximately 510, 250, and 275 years, respectively. The deep waters of the entire world ocean are replaced on average every 500 years.     

1965—2015年海河流域干旱时空变化特征分析

基于海河流域1965—2015年月降水和气温数据,利用标准化降水蒸发指数（Standardized Precipitation Evapotranspiration Index, SPEI）、Mann-Kendall检验和经验正交函数(Empirical Orthogonal Function, EOF)分析等方法,分析海河流域干旱时空特征。结果表明：1）就时间变化来看,年、春、夏季SPEI序列呈干旱化趋势,秋季呈湿润化趋势,仅夏季干旱变化通过了0.05显著性检验。年、季干旱发生频率表明春旱显著,各年代干旱站次比表明近51年来干旱范围有所增加。2）就空间变化来看,中等干旱在年、夏季集中于永定河系的东部、大清河系及北三河系,春、秋季集中于滦河河系、大清河系及漳卫河系的西部;轻度干旱在年、春、夏季集中于滦河河系、北三河系、大清河系,秋季集中于永定河系、子牙河系及漳卫河系。年、春、夏季在流域范围内呈干旱化趋势,秋季在永定河系、大清河系、北三河系及滦河河系呈湿润化趋势。3）就空间模态来看,近51年来海河流域第一模态的年、季主要时空分布型为全流域一致型,第二模态的年、夏、秋季主要时空分布型为南部—北部反向分布型,春季呈西北部—东南部反向分布型。     

Crystal structures of the adenylate sensor from fission yeast AMP-activated protein kinase

The 5'-AMP (adenosine monophosphate)-activated protein kinase (AMPK) coordinates metabolic function with energy availability by responding to changes in intracellular ATP (adenosine triphosphate) and AMP concentrations. Here, we report crystal structures at 2.9 and 2.6 A resolution for ATP- and AMP-bound forms of a core alphabetagamma adenylate-binding domain from the fission yeast AMPK homolog. ATP and AMP bind competitively to a single site in the gamma subunit, with their respective phosphate groups positioned near function-impairing mutants. Unexpectedly, ATP binds without counterions, amplifying its electrostatic effects on a critical regulatory region where all three subunits converge.