Habitat degradation of Rhinopithecus bieti in Yunnan, China

Black-and-white snub-nosed monkeys (Rhinopithecus bieti) are endemic to the Trans-Himalayas in Northwest Yunnan and Southeast Tibet between the upper Yangtze and Mekong Rivers. Based on field surveys and previous reports, we identified the dark-coniferous forest, the mixed coniferous and broadleaf forest, and oak patches as suitable habitats (SH) for the monkeys. Summer grazing lands (SGL), which were made by local people cutting and burning the dark-coniferous forest at the high altitude belt, replaced SH. To have a general view of the status of the SH in Yunnan, we estimated the areas of SH and SGL from satellite images in 1997, and compared with areas estimated from aerial photo-based maps (ca. 1958). The work resulted in: 1) the area of SH was 4,169 km(2) in 1997; 2) SGL was 1,923 km(2); 3) during the past 40 years, the area of SH decreased by 31% (1,887 km(2)), and SGL increased by 204% (1,291 km(2)); and 4) the mean size of forest patches decreased from 15.6 to 5.4 km(2). In addition, the area of SGL is positively correlated to local human population (R-2 greater than or equal to0.53), implying that the reduction and fragmentation of habitat for Rhinopithecus bieti is a result of population growth of humans, who mostly employ traditional modes of production. Only 11 monkey groups remained in the changing habitat. Considering that forests at lower elevation were also encroached upon by farmlands in a similar way, the forest ecosystem is highly threatened. The destruction will continue unless there is a change in the mode of production in the region.

Sexual differences in vigilance of paired Ruddy Shelduck in winter

The effect of distance between members of pairs of the Ruddy Shelduck (Tadorna ferruginea) during vigilance behavior was studied during winter at Lijiang Lashihai Lake Reserve, southwest China. The distance between the paired birds while feeding was grouped into three categories: <1 m, 1-3 to and >3 m. Nearly 90% of the distances recorded between paired males and females were within three meters. The degree of vigilance increased with distance apart for females, but not for males. The scanning rate of males was significantly, higher than that of females at <1 m and at 1-3 m respectively, but no significant difference occurred when the distance between them was >3 m. These results are discussed in relation to mate competition and wintering strategy; it is suggested that staving close together is the optimal strategy for members of Ruddy Shelduck pairs.

Sexual behavior in a one-male unit of Rhinopithecus bieti in captivity

Data regarding the sexual behavior of black-and-white snub-nosed monkeys (Rhinopithecus bieti) were collected in 1998 in a one-male unit in captivity by all-occurrences sampling during the mating season. Before the present study, little was known about the sexual behavior of this species. This study showed that female solicitation is mainly expressed as "prostration plus glancing laterally" (PG) or "sitting plus head moving up and down" (HM), and male solicitation is exhibited by the "grunt bared-teeth display." The mount-to-ejaculation ratio was 5.2 on average, and single-mount ejaculations (SMEs) were observed in only 4.4% of mounts on days with at least one ejaculation. Therefore, the main copulatory pattern of this species is multiple-mount ejaculation (MME). Females initiated 72% of 18 ejaculatory mounts. Females initiated more ejaculatory mounts than non-ejaculatory ones. In general, the patterns of sexual behavior in this species are similar to those reported for other Colobines. (C) 2004 Wiley-Liss, Inc.

Sleeping sites of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Baima Snow Mountain, China

Data on sleeping sites of a group of black-and-white snub-nosed monkeys Rhinopithecus bieti (Colobinae, Primates) were collected between April-July and September-December 2001 to try to determine the factors affecting site selection at Nanren (99 degrees

Birth seasonality and interbirth interval of captive Rhinopithecus bieti

This study, which is based on 10 years of birth records, shows that black-and-white snub-nosed monkeys (Rhinopithecus bieti) in captivity display marked birth seasonality. The birth season starts in December and ends in June, with a peak from March to May

Social organization of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Deqin, China

Data on social organization of two bands of black-and-white snub-nosed monkeys (Rhinopithecus bieti) 14 were collected when the monkeys were crossing an open spot at Nanren and Bamei (northwest of Yunnan, China) using a sampling rule where individuals wit

绿藻CO_2浓缩机制的研究进展

单细胞绿藻是淡水水体中浮游植物的重要组成部分 ,也是淡水生态系统中主要的初级生产者 ,其在适应外界环境CO2 浓度变化的过程中 ,细胞内形成了一种主动转移无机碳的机制———CO2 浓缩机制(CO2 concentratingmechanism ,CCM ) .该机制能使细胞在核酮糖 2 磷酸羧化氧化酶 (rubisco)固碳位点提高CO2 浓度 ,以增加光合作用和减少光呼吸 .本文综述了这种机制中的无机碳转移模型和不同环境因子 (光、温度、CO2 浓度和营养水平 )对它的调控作用 ,以期促进深入开展浮游植

Cryogenic on-chip multiplexer for the study of quantum transport in 256 split-gate devices

We present a multiplexing scheme for the measurement of large numbers of mesoscopic devices in cryogenic systems. The multiplexer is used to contact an array of 256 split gates on a GaAs/AlGaAs heterostructure, in which each split gate can be measured individually. The low-temperature conductance of split-gate devices is governed by quantum mechanics, leading to the appearance of conductance plateaux at intervals of 2e^2/h. A fabrication-limited yield of 94% is achieved for the array, and a "quantum yield" is also defined, to account for disorder affecting the quantum behaviour of the devices. The quantum yield rose from 55% to 86% after illuminating the sample, explained by the corresponding increase in carrier density and mobility of the two-dimensional electron gas. The multiplexer is a scalable architecture, and can be extended to other forms of mesoscopic devices. It overcomes previous limits on the number of devices that can be fabricated on a single chip due to the number of electrical contacts available, without the need to alter existing experimental set ups.

MRI features of cellular angiomyofibroma with pathologic correlation.

Within the spectrum of extratesticular mesenchymal tumors in the scrotum and perineum lies cellular angiofibroma, also known as angiomyofibroblastoma-like tumor, a rare lesion originally described to almost exclusively occur in the vulva, perineum, and pelvis of women. We report a case of this tumor, with an adjacent scrotal lipoma, occurring in a 60-year-old male who presented to our department with a firm palpable scrotal mass. To our knowledge, the MRI findings of this entity have yet to be described in the radiological literature. We present the MRI features of cellular angiofibroma that are consistent with the pathological characteristics of this entity-a benign cellular and fibrous tumor with prominent vascularity.

Construction and analysis of a high-CO2-requiring mutant of the cyanobacterium Anabaena sp strain PCC7120

A mutant of Anabaena sp. strain PCC7120 requiring high CO2 was generated using Tn5 mutagenesis. This is the first data for a filamentous cyanobacterium. The mutant was capable of growing at 5% CO2, but incapable of growing at air levels of CO2. Southern hybridization analysis indicated that the Anabaena genome was inserted by the transposon at one site. The apparent photosynthetic affinity of the mutant to external dissolved inorganic carbon (DIC) was about 300 times lower that of the wild type (WT), and the medium alkalization rate as well as the carboxysomal carbonic anhydrase activity of the mutant was also lower than those of the WT. When the mutant was transferred from the culture medium bubbled with 5% CO2 to higher DIC (8.4% CO2) or 1% CO2, it showed similar responses to the WT. However, aberrant carboxysomes were found in the mutant cells through ultrastructural analysis, indicating it was most probably the wrong organization of the carboxysomes that eventually led to the inefficient operation of carboxysomal carbonic anhydrase and the subsequent defectiveness of the mutant in utilizing DIC.

An inducible CO2 concentrating mechanism in cyanobacterium Anabaena sp strain PCC7120

In order to define its characteristics of the photosynthetic utilization of CO2 and HCO3- when the ambient inorganic carbon changed, HCG (High-CO2-Growing Cells) of cyanobacterium Anabaena sp. strain PCC7120 were prepared. The growth rate of HCG was higher than that of LCG (low-CO2-growing cells, i.e. air-growing cells). When the HCG cells were transferred from 5% CO2 to air levels of CO2 , a series of changes took place: its carbonic anhydrase activity as well as its photosynthetic affinity to the external inorganic carbon significantly increased; the number of the carboxysomes, which is one of the most important components of CCM in cyanobacteria also increased. These facts indicated that the CCM activity of Anabaena PCC 7120 was induced. When the pH in the medium increased from 6 to 9, the photosynthetic affinity to external inorganic carbon of both HCG and LCG declined, while the apparent photosynthetic affinity to external CO2 increased. In the light of these findings, this inducible CCM in cyanobacteria provided a good model for the study of the photosynthetic Ci utilization in the phototrophic microoganisms.

InP 基InAs 纳米结构材料的生长、光电性质与其器件应用研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z

Si(111)衬底上GaN 外延的MOCVD 生长及其应力研究

Submitted by zhangdi (zhangdi@red.semi.ac.cn) on 2009-04-13T11:45:31Z