Zircon SHRIMP U-Pb dating for the Cangshuipu volcanic rocks and its implications for the lower boundary age of the Nanhua strata in South China

Continental volcanic rocks and volcaniclastic sedi-mentary conglomerates of the Cangshuipu Formation oc- cur as wedge-shaped Neoproterozoic strata in the Yiyang region, Hunan Province. They overlie with a high-angle unconformity the Lengjiaxi Group of the Upper Meso- proterozoic Eonothem. The wedge-shaped Neoproterozoic strata of the continental clastic rocks and the Mesopro-terozoic deep marine flysch turbidites of the Lengjiaxi Group represent two distinct stages of basin-tectonic evo-…     

Cellular automata pedestrian movement model considering human behavior

The pedestrian movement is more complex than vehicular flow for the reason that people are more flexible and intelligent than car. Without the limit of 搇anes?pedestrian movement is loose and free. Furthermore, they are easily affected by other walkers as well as the environ-ment around. In this paper some special technique is intro-duced considering human behavior to make the rules more reasonable. By simulating the two-dimension pedestrian movement, the phase transition phenomena of pedestrian movement, including the up walkers moving from the bottom to the upper boundary and the right walkers moving from the left to the right boundary, are presented. Studying on the effect of the system size on the critical density shows that the critical density is independent of the system size in the scope studied in this paper.     

MAP kinase specifically mediates the ABA-induced H<Subscript>2</Subscript>O<Subscript>2</Subscript> generation in guard cells of<Emphasis Type="Italic">Vicia faba</Emphasis> L.

The plant hormone abscisic acid (ABA) is involved in regulating adverse physiological processes, including stomatal closure, seed development and germination, and mediating many environmental stress responses, such as drought, salinity and extreme temperatures[1,2]. In re-sponse to various stress stimuli, ABA synthesis is in-creased in plant cells, which triggers a series of physio-logical responses to adapt the stress conditions[1—3]. For example, under water deficit, ABA acts directly on…     

Star pattern recognition method based on neural network

Star sensor is a sensitive instrument for determina-tion of a spacecraft attitude with high accuracy. The in-strument can determine the spacecraft 3-axis attitude through the recognition of observed stars. It measures star magnitude and star coordinates in the spacecraft coordi-nate frame. The measures are then compared with a refer-ence star catalog to obtain the attitude information of the spacecraft[1,2]. The purpose of star pattern recognition is to identify the corresponding relations bet…     

Electrofusion of tobacco protoplasts in space

Electrofusion of plant cell protoplasts is a techniqueto induce fusion between protoplasts by the reversibleelectric breakdown of their plasma membranes. This method is reliable and not toxic compared with chemicalfusion. Some somatic plant cell hybrids have been suc-cessfully produced by this method[1—5]. However, it is notwidely applied in agriculture due to the low yield of vi-able hybrids[6]. The reasons resulting in the low yield ofhybrids might be as the followings: (1) different densit…     

Pollen transport in the Shiyang River drainage,arid China

In order to assess the contribution of the pollen transported by wind and fluvial flows to the pollen spectra in Shiyang River drainage,a typical small endorheic drainage in arid lands of northwest China, preliminary studies on modern pollen rain along two transects with 91 surface soil samples, 8 atmospheric samples, 30 modern fluvial flow samples and 50 riverbed mud samples, were carried out.Results show that dispersal agents (air, flowing water) have dissimilar effects on transport of pollen and the structure of pollen spectra. Fluvial flow has a stronger capacity thanwind to transport large quantities of pollen over long dis-tances. Pollen transported by fluvial flow makes a large con-tribution to the pollen spectra of riverbed alluvial sediments.Paleoenvironmental reconstructions undertaken using pollen spectra from fluvial sediments in arid lands are strongly influenced by pollen transport. Therefore, the sources, the transportation agents and the depositional condition of pol-len should be systematically investigated before pollen as-semblages are used to derive the environmental significance in such settings.     

Determination of cell volume during equilibrium freezing process

A new type electronic particle counter (EPC, Multisizer^TM 3, Beckman Coulter Inc., USA) was used to determine the volumes of human red blood cells (RBCs) in NaCl solutions of different osmolalities. The thermodynamics model describing cell response during freezing process was used to simulate the volume change of RBC in 0.9% NaCl solution during equilibrium freezing process. It was assumed that the effect of temperature on cell volume can be neglected compared to that of osmolality, then by using the phase diagram for the binary system sodium chloride/water, the osmolalities of the NaCl solution under different sub-zero temperatures can be obtained (converted from mass concentration), then the calculated values of RBC volumes can be validated by the experiments.     

Follicular growth,differentiation and atresia

Only limited numbers of primordial follicles in mammalian ovary grow and differentiate to reach the stage of dominate follicles and ovulate. 99% of the follicles in the ovary undergo atresia at various stages of development.Regulation of follicular growth, development and atresia is a complex process and involves interactions between endocrine factors and intraovarian regulators. This review summarized: i ) FSH may not be a survival factor in regulating slow-growing preantral follicles. Some locally produced growth factors, activin and orphan receptors might play a more important role at this stage, ii ) Estrogen, activin/inhibin and follistatin coordinate with FSH to regulate and control follicle differentiation, iii) There are two types of follicular atresia induced by apoptosis which originates from GC or oocyte, respectively. Early translation of tPA mRNA into tPA protein in oocyte may be associated with oocytea apoptosis.     

Numerical analysis on intermittent flow in a longitudinal section of Bingham fluid along a slope

The transition process of intermittent flow in a longitudinal section of Bingham fluid from initial distribution to fully developed state was numerically investigated in this paper. The influences of slope θ. dimensionless runoff Q* and viscosity μ0* on the dimensionless surge speed U* were also presented in a wide range of parameters. By one typical example, the intermittent flow possessed wave characteristics and showed a supercritical flow conformation for a fully developed flow. The distributions of gravity and bed drag along the flow path and the velocity distribution of flow field were also analyzed.     

Synthesis and properties of water-soluble oligo-（p-phenylkene vinylene）

A water-soluble oligo(p-phenylkene vinylene)[4,4′-(1,4-phenylene dithenylene)-bis-(N-methyl pyridinium iodide)] was synthesized by Witting reaction. The oligomer was characterized by NMR, elemental analysis, UV-visible spectrum, surface photovoltage spectrum and fluorescence spectrum.