Investigation of Spatial Distribution of Radiocesium in a Paddy Field as a Potential Sink

Surface soils, under various land uses, were contaminated by radionuclides that were released by the Fukushima Daiichi Nuclear Power Plant accident. Because paddy fields are one of the main land uses in Japan, we investigated the spatial distribution of radiocesium and the influence of irrigation water in a paddy field during cultivation. Soil core samples collected at a paddy field in Fukushima showed that plowing had disturbed the original depth distribution of radiocesium. The horizontal distribution of radiocesium did not show any evidence for significant influence of radiocesium from irrigation water, and its accumulation within the paddy field, since the original amount of radiocesium was much larger than was added into the paddy field by irrigation water. However, it is possible that rainfall significantly increases the loading of radiocesium.published_or_final_versio

Baseline for ostracod-based northwestern Pacific and Indo-Pacific shallow-marine paleoenvironmental reconstructions: ecological modeling of species distributions

Fossil ostracods have been widely used for Quaternary paleoenvironmental reconstructions, especially in marginal marine environments (e.g., for water depth, temperature, salinity, oxygen levels, pollution). But our knowledge of indicator species autoecology, the base of paleoenvironmental reconstructions, remains limited and commonly lacks robust statistical support and comprehensive comparison with environmental data. We analyzed marginal marine ostracod taxa at 52 sites in Hong Kong for which comprehensive environmental data are available. We applied linear regression models to reveal relationships between species distribution and environmental factors for 18 common taxa (mainly species, a few genera) in our Hong Kong dataset and identified indicator species of environmental parameters. For example, Sinocytheridea impressa, a widely distributed euryhaline species throughout the East and South China Sea and the Indo-Pacific, indicates eutrophication and bottom-water hypoxia. Neomonoceratina delicata, a widely known species from nearshore and estuarine environments in the East and South China Sea and the Indo-Pacific, indicates heavy metal pollution and increased turbidity. The 18 taxa used for this study are widely distributed geographically and divided into the following groups: widespread (throughout the northwestern Pacific and Indo-Pacific regions), temperate (South China Sea to Russia (Sea of Japan coast) and Japan), subtropical (Indo-Pacific to the East China Sea), tropical (Indo-Pacific and South China Sea), and globally distributed. With statistical support from ecological modeling and comprehensive environmental data, these results provide a robust baseline for ostracod-based Quaternary–Anthropocene paleoenvironmental reconstructions in the tropical–extratropical northwestern Pacific and Indo-Pacific. Highlights. We provide a robust baseline for ostracod-based (microscopic Arthropods) paleoenvironmental reconstructions from Quaternary and Anthropocene marginal marine sediments. The studied species have wide distributions over the tropics and extratropics of the northwestern Pacific and Indo-Pacific. Ecological modeling has established ostracod species as reliable indicators for paleoenvironmental reconstructions.</ol

Shallow marine ostracode distribution in Hong Kong

Oral PresentationHong Kong is one of the largest and most rapidly developing cities in Asia. It is known that the marine ecosystems of Hong Kong have been seriously influenced by a variety of anthropogenic factors, including eutrophication, bottom trawling, coastal reclamation, pollution, etc. Crustacean ostracodes are known to be sensitive to such environmental degradation. However, basic information of ostracode distribution is limited in Hong Kong. Here we investigated spatial distribution of modern ostracode assemblages in grab samples. Preliminary results obtained from 55 sites covering most areas of Hong Kong …postprin

Pathfinder cells provide a novel therapeutic intervention for acute kidney injury

Pathfinder cells (PCs) are a novel class of adult-derived cells that facilitate functional repair of host tissue. We used rat PCs to demonstrate that they enable the functional mitigation of ischemia reperfusion (I/R) injury in a mouse model of renal damage. Female C57BL/6 mice were subjected to 30 min of renal ischemia and treated with intravenous (i.v.) injection of saline (control) or male rat pancreas-derived PCs in blinded experimentation. Kidney function was assessed 14 days after treatment by measuring serum creatinine (SC) levels. Kidney tissue was assessed by immunohistochemistry (IHC) for markers of cellular damage, proliferation, and senescence (TUNEL, Ki67, p16ink4a, p21). Fluorescence in situ hybridization (FISH) was performed to determine the presence of any rat (i.e., pathfinder) cells in the mouse tissue. PC-treated animals demonstrated superior renal function at day 14 post-I/R, in comparison to saline-treated controls, as measured by SC levels (0.13 mg/dL vs. 0.23 mg/dL, p&#60;0.001). PC-treated kidney tissue expressed significantly lower levels of p16ink4a in comparison to the control group (p=0.009). FISH analysis demonstrated that the overwhelming majority of repaired kidney tissue was mouse in origin. Rat PCs were only detected at a frequency of 0.02%. These data confirm that PCs have the ability to mitigate functional damage to kidney tissue following I/R injury. Kidneys of PC-treated animals showed evidence of improved function and reduced expression of damage markers. The PCs appear to act in a paracrine fashion, stimulating the host tissue to recover functionally, rather than by differentiating into renal cells. This study demonstrates that pancreatic-derived PCs from the adult rat can enable functional repair of renal damage in mice. It validates the use of PCs to regenerate damaged tissues and also offers a novel therapeutic intervention for repair of solid organ damage in situ

The Cryogenic System for the Panda-X Dark Matter Search Experiment

Panda-X is a liquid xenon dual-phase detector for the Dark Matter Search. The first modestly-sized module will soon be installed in the China JinPing Deep Underground Laboratory in Sichuan province, P.R. China. The cryogenics system is designed to handle much larger detectors, even the final version in the ton scale. Special attention has been paid to the reliability, serviceability, and adaptability to the requirements of a growing experiment. The system is cooled by a single Iwatani PC150 Pulse Tube Refrigerator. After subtracting all thermal losses, the remaining cooling power is still 82W. The fill speed was 9 SLPM, but could be boosted by LN2 assisted cooling to 40 SLPM. For the continuous recirculation and purification through a hot getter, a heat exchanger was employed to reduce the required cooling power. The recirculation speed is limited to 35 SLPM by the gas pump. At this speed, recirculation only adds 18.5 W to the heat load of the system, corresponding to a 95.2 % efficiency of the heat exchanger.Comment: 10 pages, 5 figure

Dynamics of Simple Balancing Models with State Dependent Switching Control

Time-delayed control in a balancing problem may be a nonsmooth function for a variety of reasons. In this paper we study a simple model of the control of an inverted pendulum by either a connected movable cart or an applied torque for which the control is turned off when the pendulum is located within certain regions of phase space. Without applying a small angle approximation for deviations about the vertical position, we see structurally stable periodic orbits which may be attracting or repelling. Due to the nonsmooth nature of the control, these periodic orbits are born in various discontinuity-induced bifurcations. Also we show that a coincidence of switching events can produce complicated periodic and aperiodic solutions.Comment: 36 pages, 12 figure

Studies of ultra-intense laser plasma interactions for fast ignition

Copyright 2000 American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics. The following article appeared in Physics of Plasmas, 7(5), 2014-2022, 2000 and may be found at http://dx.doi.org/10.1063/1.87402

Modelled ocean changes at the Plio-Pleistocene transition driven by Antarctic ice advance

The Earth underwent a major transition from the warm climates of the Pliocene to the Pleistocene ice ages between 3.2 and 2.6 million years ago. The intensification of Northern Hemisphere Glaciation is the most obvious result of the Plio-Pleistocene transition. However, recent data show that the ocean also underwent a significant change, with the convergence of deep water mass properties in the North Pacific and North Atlantic Ocean. Here we show that the lack of coastal ice in the Pacific sector of Antarctica leads to major reductions in Pacific Ocean overturning and the loss of the modern North Pacific Deep Water (NPDW) mass in climate models of the warmest periods of the Pliocene. These results potentially explain the convergence of global deep water mass properties at the Plio-Pleistocene transition, as Circumpolar Deep Water (CDW) became the common source