Assessing soil erosion rates on manually-tilled hillslopes in the Sichuan Hilly Basin using Cs-137 and Pb-210(ex) measurements

IEECAS SKLLQG

Late Pliocene-Pleistocene changes in mass accumulation rates of eolian deposits on the central Chinese Loess Plateau

IEECAS SKLLQG

Estimation of wind erosion rates by using Cs-137 tracing technique: A case study in Tariat-Xilin Gol transect, Mongolian Plateau

Wind erosion is one of the major environmental problems in semi-arid and arid regions. Here we established the Tariat-Xilin Gol transect from northwest to southeast across the Mongolian Plateau, and selected seven sampling sites along the transect. We then estimated the soil wind erosion rates by using the Cs-137 tracing technique and examined their spatial dynamics. Our results showed that the Cs-137 inventories of sampling sites ranged from 265.63 +/- 44.91 to 1279.54 +/- 166.53 Bq.m(-2), and the wind erosion rates varied from 64.58 to 419.63 t.km(-2).a(-1) accordingly. In the Mongolia section of the transect (from Tariat to Sainshand), the wind erosion rate increased gradually with vegetation type and climatic regimes; the wind erosion process was controlled by physical factors such as annual precipitation and vegetation coverage, etc., and the impact of human activities was negligible. While in the China section of the transect (Inner Mongolia), the wind erosion rates of Xilin Hot and Zhengxiangbai Banner were thrice as much as those of Bayannur of Mongolia, although these three sites were all dominated by typical steppe. Besides the physical factors, higher population density and livestock carrying level should be responsible for the higher wind erosion rates in these two regions of Inner Mongolia.

Growth rates of different polymorphs from interspherulitic boundary profiles

Quantitative data on the crystallization kinetics of polymorphic polymers can be derived from the investigation of gross spherulitic morphology formed in isothermal conditions. Depending on distance between centers, and the time lag between their formation and relative growth rates, various types of boundary lines can be generated by the impinging of two spherical bodies whose radii increase linearly with time, In polymorphic polymers, different types of spherulites often develop simultaneously at different rates from sporadic or predetermined nuclei. In same cases, the so-called growth transformation, in which a nucleus of the fast growing specie is formed at the tip of an advancing lamella of the slower crystal form, provides an alternative mode of nucleation, It is shown that if only one event of growth transformation takes place at the front of a slow growing body, the fast growing spherulite swallows the parent one and the resultant shape of interspherulitic boundary is described by two symmetrical logarithmic spirals whose parameters can be extracted from micrographs taken at the end of crystallization. These concepts are applied to determine the radial growth rate of gamma form spherulites of polypivalolactone in a wide range of temperatures through analysis of the alpha/gamma interspherulitic profiles formed in isothermal conditions and direct measurement of the growth rate of the alpha counterparts at the same temperature.

EFFECTS OF CRYSTALLIZATION RATES ON INTERFACE LAYER THICKNESS OF EPITAXIAL HDPE ON ORIENTED IPP

The effect of crystallization rate on the epitaxial interface layer thickness of high-density polyethylene (HDPE) in the epitaxial system with oriented isotactic polypropylene (iPP) has been investigated by electron microscopy. The results of bright-field

Extra- and intra-cellular ice formation of red seabream (Pagrus major) embryos at different cooling rates

The ice crystal formation is assumed as the most lethal factor for the failure of fish embryo cryopreservation and intracellular ice formation (IIF) plays a central role in cell injury during cooling. The objectives were to observe the morphological changes of red seabream (Pagrus major) embryo during the cooling-thawing process, and to examine the effect of cryoprotectant and cooling rate on the temperatures of oil globule ice formation (T-OIF), extra-cellular ice formation (T-EIF) and intracellular ice formation (T-IIF) using cryomicroscope. After thawing, the morphological changes of embryos were observed and recorded by the video attachment and monitor under the microscope. During the cooling process, three representative phenomena were observed: oil globule gradually turned bright firstly, then the whole field of view flashed and the embryo blackened. Cooling rate affect the temperature of both extra- and intra-cellular ice formations. T-EIF and T-IIF at high cooling rate were much lower than that at low cooling rate. And the value of T-EIF - T-IIF increased from 0.45 to 11.11 degrees C with the increase of cooling rate from 3 to 130 degrees C/min. Taken together, our results suggested that high cooling rate with proper cryoprotectant would be a good option for red seabream embryo cryopreservation. (C) 2009 Elsevier Inc. All rights reserved.

Comparison between compsopogon coeruleus and porphyra yezoensis in their O-2 evolution rates and phycobilisome composition

In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P yezoensis was R-phycoerythrin containing alpha, beta, and gamma subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of alpha, beta, and gamma subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type.

A genetic linkage map of Pacific white shrimp (Litopenaeus vannamei): sex-linked microsatellite markers and high recombination rates

Pacific white shrimp (Litopenaeus vannamei) is the leading species farmed in the Western Hemisphere and an economically important aquaculture species in China. In this project, a genetic linkage map was constructed using amplified fragment length polymorphism (AFLP) and microsatellite markers. One hundred and eight select AFLP primer combinations and 30 polymorphic microsatellite markers produced 2071 markers that were polymorphic in either of the parents and segregated in the progeny. Of these segregating markers, 319 were mapped to 45 linkage groups of the female framework map, covering a total of 4134.4 cM; and 267 markers were assigned to 45 linkage groups of the male map, covering a total of 3220.9 cM. High recombination rates were found in both parental maps. A sex-linked microsatellite marker was mapped on the female map with 6.6 cM to sex and a LOD of 17.8, two other microsatellite markers were also linked with both 8.6 cM to sex and LOD score of 14.3 and 16.4. The genetic maps presented here will serve as a basis for the construction of a high-resolution genetic map, quantitative trait loci (QTLs) detection, marker-assisted selection (MAS) and comparative genome mapping.

Sedimentation rates and provenance analysis in the Southwestern Okinawa Trough since the mid-Holocene

As a high-sedimentation rate depocenter along the path of the Kuroshio Current, the southwesternmost part of the Okinawa Trough is a key area to understand the Kuroshio history and sediments transportation. A 34.17-m-long sediment core was obtained by the advanced piston corer of Marco Polo/IMAGES XII MARION DUFRESNE during the May 2005 from the Southern Okinawa Trough at site MD05-2908. The recovered sediments were analyzed by AMS C-14 dating, coarse size fraction (> 63 mu m) extraction and moisture content determination in order to study its sedimentation flux and provenance. The depth-age relationship of core MD05-2908 was well constrained by 17 C-14 dating points. The sediments span across the mid-Holocene (6.8 ka B.P.) and have remarkablely high sedimentation rates between 1.8 and 21-2 m/ka, which is well consistent with the modern observations from sediment traps. We identified five 70-200 a periods of abnormally rapid sedimentation events at 6790-6600 a B.P., 5690-5600 a B.P., 4820-4720 a B.P., 1090-880 a B.P., and 260-190 a B.P., during which the highest sedimentation rate is up to 21-2 m/ka. In general, the lithology of the sediments were dominated by silt and clay, associated with less than 5% coarse size fraction (a parts per thousand << 63 mu m). As the most significant sediment source, the Lanyang River in northeastern Taiwan annually deliver about 10Mt materials to the coastal and offshore region of northeast Taiwan, a portion of which could be carried northward by currents toward the study area. Therefore, we concluded that the 5 abnormally rapid sedimentation events may be related to intensified rainfall in Taiwan and thus increased materials to our study area at that time. However, a few extreme-rapid sedimentation events cannot be explained by normal river runoff alone. The large earthquakes or typhoons induced hyperpycnal discharge of fluvial sediment to the ocean may also act as a potential source supply to the Okinawa Trough.

The sedimentation rates in the Okinawa trough during the Late Quaternary

On the basis of accelerator mass spectrometer radiocarbon (AMS C-14) dating, sedimentation rates of 11 cores collected from the northern to southern Okinawa Trough are discussed. The sedimentation rates in the Okinawa Trough roughly range from 11 to 39 cm/ka, and the average is 23.0 cm/ka. China's continental matter is the main sediment source of the middle Okinawa Trough and has important contribution to the northern and southern Okinawa Trough. The sedimentation rates during the marine oxygen isotope (MI5) 2 are uniformly higher than those during MIS 1 in the northern and middle Okinawa Trough while they are on the contrary in the southern Okinawa Trough. Sedimentation rates in the Okinawa Trough can be one of the proxies of sediment source and an indicator of cooling events.

Modification to the Hardisty equation, regarding the relationship between sediment transport rate and particle size

Bagnold-type bed-load equations are widely used for the determination of sediment transport rate in marine environments. The accuracy of these equations depends upon the definition of the coefficient k(1) in the equations, which is a function of particle size. Hardisty (1983) has attempted to establish the relationship between k(1) and particle size, but there is an error in his analytical result. Our reanalysis of the original flume data results in new formulae for the coefficient. Furthermore, we found that the k(1) values should be derived using u(1) and u(1cr) data; the use of the vertical mean velocity in flumes to replace u(1) will lead to considerably higher k(1) values and overestimation of sediment transport rates.