一般化凸空间上的Ky Fan型重叠定理和不动点定理

在本文，我们根据已有的结论得到了若干个一般化凸空间上Ky Fan型重叠定理和Fan-Browder型不动点定理。     

Net carbon dioxide losses of northern ecosystems in response to autumn warming

The carbon balance of terrestrial ecosystems is particularly sensitive to climatic changes in autumn and spring, with spring and autumn temperatures over northern latitudes having risen by about 1.1 degrees C and 0.8 degrees C, respectively, over the past two decades. A simultaneous greening trend has also been observed, characterized by a longer growing season and greater photosynthetic activity. These observations have led to speculation that spring and autumn warming could enhance carbon sequestration and extend the period of net carbon uptake in the future. Here we analyse interannual variations in atmospheric carbon dioxide concentration data and ecosystem carbon dioxide fluxes. We find that atmospheric records from the past 20 years show a trend towards an earlier autumn-to-winter carbon dioxide build-up, suggesting a shorter net carbon uptake period. This trend cannot be explained by changes in atmospheric transport alone and, together with the ecosystem flux data, suggest increasing carbon losses in autumn. We use a process-based terrestrial biosphere model and satellite vegetation greenness index observations to investigate further the observed seasonal response of northern ecosystems to autumnal warming. We find that both photosynthesis and respiration increase during autumn warming, but the increase in respiration is greater. In contrast, warming increases photosynthesis more than respiration in spring. Our simulations and observations indicate that northern terrestrial ecosystems may currently lose carbon dioxide in response to autumn warming, with a sensitivity of about 0.2 PgC degrees C(-1), offsetting 90% of the increased carbon dioxide uptake during spring. If future autumn warming occurs at a faster rate than in spring, the ability of northern ecosystems to sequester carbon may be diminished earlier than previously suggested.     

猪繁殖与呼吸障碍综合征的RT-PCR诊断

根据猪繁殖与呼吸障碍综合征病毒（Porcine reproductive and respiratory syndrome virus,PRRSV）的全基因组序列,设计合成一对特异性引物,建立检测PRRSV的RT-PCR方法。对两份疑似病料进行检测,结果两份均为猪繁殖与呼吸障碍综合征病毒阳性。结合流行病学,临床症状以及病理解剖变化,诊断为猪繁殖与呼吸障碍综合征病毒感染。     

New developments of MSRT’s working modes: One-dimensional radio heliograph and IPS telescope

This note introduces the newly developed working modes, i.e. one-dimensional meter-wave radio heliograph (MRH) and interplanetary scintillation (IPS) telescope, of meter-wave aperture synthesis radio telescope (MSRT) at Beijing Astronomical Observatory (BAO). The note describes briefly the scientific objectives, configurations of the hardware and software, and functions of the system. It presents the examples of observations on solar meter-wave bursts and IPS with the two new working modes. The results indicated that new modes not only can provide the information on the evolution of solar activities with space and time, but also can trace and monitor the propagation and spatial distribution of interplanetary plasma shock resulting from solar activities and the instability of the ionosphere, etc. Both modes are new facilities that could fill the gaps in scientific frontiers.     

The adhesion receptor GPR56 is activated by extracellular matrix collagen III to improve β-cell function

Aims

G-protein coupled receptor 56 (GPR56) is the most abundant islet-expressed G-protein coupled receptor, suggesting a potential role in islet function. This study evaluated islet expression of GPR56 and its endogenous ligand collagen III, and their effects on β-cell function.

Methods

GPR56 and collagen III expression in mouse and human pancreas sections was determined by fluorescence immunohistochemistry. Effects of collagen III on β-cell proliferation, apoptosis, intracellular calcium ([Ca²⁺]_i) and insulin secretion were determined by cellular BrdU incorporation, caspase 3/7 activities, microfluorimetry and radioimmunoassay, respectively. The role of GPR56 in islet vascularisation and innervation was evaluated by immunohistochemical staining for CD31 and TUJ1, respectively, in pancreases from wildtype (WT) and Gpr56^?/? mice, and the requirement of GPR56 for normal glucose homeostasis was determined by glucose tolerance tests in WT and Gpr56^?/? mice.

Results

Immunostaining of mouse and human pancreases revealed that GPR56 was expressed by islet β-cells while collagen III was confined to the peri-islet basement membrane and islet capillaries. Collagen III protected β-cells from cytokine-induced apoptosis, triggered increases in [Ca²⁺]_i and potentiated glucose-induced insulin secretion from WT islets but not from Gpr56^?/? islets. Deletion of GPR56 did not affect glucose-induced insulin secretion in vitro and it did not impair glucose tolerance in adult mice. GPR56 was not required for normal islet vascularisation or innervation.

Conclusion

We have demonstrated that collagen III improves islet function by increasing insulin secretion and protecting against apoptosis. Our data suggest that collagen III may be effective in optimising islet function to improve islet transplantation outcomes, and GPR56 may be a target for the treatment of type 2 diabetes.

     

鞘铁菌(Siderocapsa)固锰的生化分析

从鞍山大赵台天然水滤池中分离出固锰能力很强的二种鞘铁菌,经胰酶处理菌体表面,破碎菌体,以及用胰酶和酶抑制剂处理菌体破碎后的内含物等实验表明,鞘铁菌的固锰能力可能是由于菌体内具有固锰能力的酶系所致。     

自来水厂除锰滤池Mn~(2+)氧化细菌的分离及其活性的研究

从沈阳石佛寺自来水厂除锰滤池中分离得到7株能够催化Mn2+氧化的细菌，并就催化因子的分离作了尝试．结果表明，Mn2+诱导催化氧化能力，催化活性因子在细胞上；培养基中的有机物浓度影响活性表达，有机物浓度升高，细菌生长加快，但活性表达被抑制．     

一种仿人机器人行走距离预测方法

针对仿人机器人NAO实际行走距离受环境因素(如脚底打滑)和自身因素(如关节的反作用力)的影响,导致其与理论期望距离有一定偏差的情况,提出了一种基于自适应神经模糊推理系统的行走距离预测方法.通过获得NAO行走距离的相关数据,采用网格分割法,构建自适应模糊推理系统来预测机器人实际行走的距离.训练时采用网格分割、BP算法和最...     

可保持最大吞吐量的IEEE 802.11 DCF协议功率控制机制

在无线Ad Hoc网络中使用功率控制不仅可以节省能耗,还能提高网络吞吐量。基于IEEE 802.11 DCF协议,提出了一种新的适用于车辆自组织网络的功率控制算法。该算法根据节点的通信状况,动态地调整接收节点的CTS帧发射功率和发送节点的数据包发射功率,进而根据使网络吞吐量达到最大时的最佳接入节点数目调节RTS帧的发射功率,从而避免冲突,增大吞吐量。仿真表明该算法不仅能降低平均能耗,延长网络生存时间,还能增大网络复用率,提高网络的平均吞吐量。     

Frequency domain polarization weighted ESPRIT method for bearing angle

The signal to noise ratio （SNR） of seismic waves is usually very low after long distance transmission. For this condition, to improve the bearing estimation capability in the low SNR, a frequency domain polarization weighted ESPRIT method using a single vector device is proposed. The frequency domain polari- zation parameters extracted from the signals are used to design the weighted function which is applied to the received signals. The bearing angle and the target frequency are estimated through ESPRIT using the weighted signals. The simulation and experiment results show that the presented method can obtain accurate estimation values under the low SNR with little prior information.