Search

Variation in two SNPs and one microsatellite on the Y chromosome was analyzed in a total of 663 rams representing 59 breeds from a large geographic range in northern Eurasia. SNPA-oY1 showed the highest allele frequency (91.55%) across the breeds, whereas SNPG-oY1 was present in only 56 samples. Combined genotypes established seven haplotypes (H4, H5, H6, H7, H8, H12 and H19). H6 dominated in northern Eurasia, and H8 showed the second-highest frequency. H4, which had been earlier reported to be absent in European breeds, was detected in one European breed (Swiniarka), whereas H7, which had been previously identified to be unique to European breeds, was present in two Chinese breeds (Ninglang Black and Large-tailed Han), one Buryatian (Transbaikal Finewool) and two Russian breeds (North Caucasus Mutton-Wool and Kuibyshev). H12, which had been detected only in Turkish breeds, was also found in Chinese breeds in this work. An overall low level of haplotype diversity (median h = 0.1288) was observed across the breeds with relatively higher median values in breeds from the regions neighboring the Near Eastern domestication center of sheep. H6 is the dominant haplotype in northwestern and eastern China, in which the haplotype distribution could be explained by the historical translocations of the H4 and H8 Y chromosomes to China via the Mongol invasions followed by expansions to northwestern and eastern China. Our findings extend previous results of sheep Y chromosomal genetic variability and indicate probably recent paternal gene flows between sheep breeds from distinct major geographic regions.

The Xiuyan impact crater with a rim-rim diameter of 1.8 km is located at northern hills in the Liaodong peninsula, Liaoning province, China, which is well reserved and confirmed by evidences from different sources to be a meteorite impact crater. A special geophysical field formed from the meteorite impact and subsequent deposit at the crater makes different medium velocity and density between inside and outside of the crater. In the project, velocity structures, stratum structures and whole configuration of the crater are gotten using the differences of seismic velocity and wave impedance from the combined exploration of reflection and refraction. Based on the reflection features of strata, the crater body formed by the direct impact has a diameter about 1.8 km and a depth about 800 m, and the depth affected by the impact is about 1.4 km. The crater structure is divided into 3 parts, slow deposition area, rapid deposition area and affected area. According to the seismic velocity features, the velocity at the crater center reaches 7.0 km/s at the depth of 800 m. The 7.0 km/s isoline is consistent with the crater configuration, but the velocity reaches 7.0 km/s at the depth of 500~600 m in the edge of the crater. The structure of the crater body and the physical property of rocks conform further that the Xiuyan crater is originated from meteorite impact.

Until 2009, 176 meteorite impact craters have been found in the world. Since the 80's of 20th century, Chinese scholars have confirmed, from the geological, geochemical and drilling data, that a circular structure was formed by meteorite impacting in Xiuyan County, Liaoning Province. But the deep structures and the overall characteristics of the crater need still to be confirmed by using the geophysical methods. In this paper, three-dimensional Q structure has been obtained for the first time by using seismic refraction data in order to have a total understanding of the crater. Q value structure is of great significance for understanding the non-elastic and nonuniform nature of the crust. Using three-dimensional Q tomography method based on absorption characteristic time t* the amplitude spectra have been obtained and by fitting the amplitude spectrum, t* values have been obtained, which reflect seismic wave attenuation. The three-dimensional Q value structure has been obtained by using t* values through three-dimensional Q tomography method. The results showed that the Q-value layer from the surface to the depth of 100 m within the crater corresponds to the upper 107 m thick lake sediments, the Q-value layer from the depth of 100 m to 300 m corresponds to the lower 188 m thick breccia accumulation lens. The Q-value layer from the depth of 300 m to 700 m corresponds to the broken Lower Proterozoic metamorphic rock layer with less impacting. The wave impedance interface about 250 m deep corresponds to the meteorite impact interface confirmed by geological drilling at the 260 m depth.

A high resolution deep seismic reflection profile of 68.9 km long across the Yinchuan faulted basin has been accomplished which for the first time yields the fine crustal structures, characteristics of deep fault system (Yellow River fault, Yinchuan fault and Eastern piedmont fault of Helanshan) of faulted basin in graben style, and the relationship between shallow and deep structures in Yinchuan basin. The results show that the upper crust is the region above a reflector with 8 s two-way traveling time (about 20 km deep), there are many strata in the upper part of the upper crust where the continuity of different segment of stratum is good, and there is no obvious layered feature in the lower part of upper crust, where the geological structure is simple. The reflection energy is weak in the lower crust (8~13 s), where reflection events are not obvious. The crust-mantle transitional zone (around 13 s) below the lower crust consists of a group of reflection sequences that have stronger energy and longer duration (1.5 s), and the thickness is about 4.5 km. Luhuatai fault and Yinchuan fault merge into the Eastern piedmont fault of Helanshan in the depth of 12~12.5 km and 18~19 km, respectively, the Eastern piedmont fault of Helanshan merges into Yellow River fault in the depth of 28~29 km, and Yellow River fault is a deep fault cutting the Moho. Yinchuan graben is a negative flower structure that is assembled mainly by Yellow River fault and secondarily by other faults. Based on the relationship between the Eastern piedmont fault of Helanshan and Yinchuan fault, it is thought that the Eastern piedmont fault of Helanshan played a controlling role in 1739 M=8 Pingluo-Yinchuan earthquake.

Based on P-wave, S-wave velocity structures and Poisson's ratio of the Maqin-Lanzhou-Jingbian seismic refraction/wide angle reflection profile, which crosses the northern Bayan Har block, the Qinling block, the Qilian block, the Haiyuan arcuate tectonic region, and the Ordos block, the crustal composition of the northeastern margin of the Tibetan plateau is studied and the geodynamic issues are discussed. At first, a set of feasible methods are systemically summed up, with which in situ P-wave velocities observed by deep seismic sounding can be corrected to the velocity under the special condition of temperature and pressure in the laboratory. It is the key to the methods to get temperatures in the crust using heat flow. The second, in situ P-wave velocities of the profile are corrected to the velocities under a standard pressure of 600 MPa and room temperature, the corrected velocities, combined with Poisson's ratio, are compared with laboratory measurements of ultrasonic velocities, and the crustal petrologic composition is determined in the study area. Results show that the average corrected velocity in the northeastern margin of the Tibetan plateau is 6.43 km/s, and the bulk crustal composition is felsic like the composition of the upper crust. In the Bayan Har block and southern part of the Qinling block, there is a lack of Vp > 6.9 km/s mafic rock layer in the lowest crust, instead there are alternating felsic and intermediate layers in the lower crust, and the bulk composition of the lower crust is felsic. In other blocks, there is a 2~10 km thick mafic layer of Vp > 6.9 km/s and the bulk composition is intermediate in the lower crust. At last, on the basis of the crustal structure and composition in the northeastern margin of the Tibetan plateau, the opinion that crustal thickening occurred mainly in the lower crust is supported, and it is proposed that delamination possibly occurred in the lower crust of the Bayan Har block and southern Qinling block in the recent geologic time, which accelerated the uplift of the Tibetan plateau.

Hemp is cooked and bleached in alkali-H2O2 one-bath. The analysis of physical and chemical properties related to acid, alkali, and hydrogen peroxide about various types of components in hemp such as hemicelluloses and pectin, and lignin components makes it ascertained. In this one-bath process, alkali and H2O2 have cooperative effects to remove most proportions of the noncellulosic components efficiently. The additive MgSO4 and a stabilizer of H2O2 as auxiliary agents are introduced to protect cellulose from degradation and, meanwhile, they improve the efficiency of H2O2. The universal rotatable composite experiment design is employed to get the highly precise equation, in which the variables of NaOH and H2O2 concentrations, and the processing time are considered to be the main technological parameters of this alkali-H2O2 one-bath process. The residual gum content and residual lignin content of hemp fiber are the evaluation indexes. Based on regression equations, the figures are plotted to analyze the influences of parameters on the evaluation indexes; the optimization multicriteria mathematical model is simultaneously established to obtain the optimum parameters. Finally, an experiment is carried out to further test the acceptance of the calculated optimum values. It is shown that, for the hemp taken from Anhui Province of China, this alkali-H2O2 one-bath process can substantially remove gum and lignin from raw hemp. NaOH 10.5 g/L, H2O2 9.8 g/L, and the processing time of 127 min with 0.1% MgSO4 + 2.7 g/L stabilizer of H2O2 at 100°C are recommended to be the optimum parameters; then, a compromise is achieved among the lowest lignin content, the residual gum content, and the best strength and whiteness of hemp fiber. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 2279–2285, 2005

We compare estimates of three-dimensional brain activity extracted from averaged and from selected single-trial rnagnetoencephalographic signals, in order to study activation sequences related to motor preparation, inhibition, and movement, cued on two tones (Sl and 52). We studied all possible hand-ear combinations in a right-handed subject in both initiation and inhibition, and found some marked differences between combinations. Averaging revealed activity in the right motor cortex in all combina- tions requiring movement inhibition, irrespective of laterality of finger and ear, and in the contralateral motor cortex during movement (but considerably reduced for the task with the practiced ear and finger). These activation patterns are seen in single trials with variability of latency but not position. In the average signal, a long silent period between the warning and imperative stimuli is seen; in single trials, however, recurring sequences of activation linking frontal and posterior areas are seen throughout the analysis period in all combinations. These results show that single-trial analysis is needed to understand all the significant neural correlates of this task.