探索一种监测典型草原草场退化的新方法--结合群落样方调查资料和卫星遥感数据（TM）

大范围、实时、准确地监测典型草原地区草场退化或健康状况对于草原生态系统的保育、农牧业的可持续性发展具有非常重要的意义。比起传统的群落学研究方法，遥感技术对于监测大尺度的植被状况具有无可争议的优越性，并且已经被广泛引入监测植被覆盖变化的研究中。本项研究系统地分析、综述了过去用非遥感手段对放牧和草场退化的关注和研究，介绍了遥感技术应用于植被研究的理论基础、主要途径（植被指数）、有关领域的研究进展。特别是本文提出草场退化状况或整体健康状况可以由基干相互独立的层面表示，而过去监测植被变化主要依赖的NDVI等植被指数只能监测草原植被的个别层面（总量层）。 本文以草场放牧退化比较典型的内蒙古锡林河流域为研究对象，在进行了大量的野外样方调查的基础上，提出一种结合群落样方调查和遥感技术的监测草场健康状况的新方法。本文引入主成份分析方法（PCA），从包含12个反映群落各方面信息的变量中提取出3个有特定生态学意义的主成份，并进一步对其进行分析组合，得出一个能比较敏感、全面反映群落健康状况的新指标-草场健康指数（GHI）。 从6波段的植被光谱反射数据中比较理想地提取出2个主成份：可见光因子和红外光因子。表征群落总量、放牧退化的主成份和GHI与样方光谱反射值有相当的相关性，由此得到GHI与可光、红外光因子的回归模型。 应用此模型到卫星遥感数据（TM），得到GHI影像，并与同一数据的NDVI影像作对比研究，发现GHI在反映放牧等人为干扰对草原植被的影响效应方面比NDVI有明显的优点。此外，GHI影像对植被分布格局，特别是斑块结构有更好的显示效果。应用GHI到历史TM数据，对所研究地域的植被覆盖变化、农牧业的变迁模式等进行了定性研究。研究还发现有较长放牧史的过度放牧区的植被类型没有沿牧压梯度的规律性分布，而是呈随机斑块分布模式。

Results of the Austrian-Ceylonese hydrobiological mission 1970 of the Institute of Zoology of the University of Vienna (Austria) and the Department of Zoology of the University of Sri Lanka, Vidyalankara Campus, Kelaniya. Pt. 19. Aquatic and semiaquatic Hemiptera of Sri Lanka from the Austrian Indo-Pacific expedition, 1970-71

This report concerns the aquatic and semiaquatic Hemiptera collected in Sri Lanka by Prof. Starmühlner and Prof. Costa during November and December 1970. A surprising number of new species have been found in the Starmühlner-Costa material, even in groups for which comprehensive revisions exist. Seven new species are described here.

Tm-doped fiber laser mode-locked by graphene-polymer composite

We demonstrate mode-locking of a thulium-doped fiber laser operating at 1.94 μm, using a graphene-polymer based saturable absorber. The laser outputs 3.6 ps pulses, with ∼0.4 nJ energy and an amplitude fluctuation ∼0.5%, at 6.46 MHz. This is a simple, low-cost, stable and convenient laser oscillator for applications where eye-safe and low-photon-energy light sources are required, such as sensing and biomedical diagnostics. © 2012 Optical Society of America.

2 to 3 μm Raman-soliton continuum enabled by a nanotube mode-locked Tm-doped MOPFA

We demonstrate a Raman-soliton continuum extending from 2 to 3 μm, in a highly germanium-doped silica-clad fiber, pumped by a nanotube mode-locked thulium-doped fiber system delivering 12 kW sub-picosecond pulses at 1.95 μm. © OSA 2013.

DE-71-induced apoptosis involving intracellular calcium and the Bax-mitochondria-caspase protease pathway in human neuroblastoma cells In vitro

Polybrominated diphenyl ethers (PBDEs) are used extensively as flame-retardants and are ubiquitous in the environment and in wildlife and human tissue. Recent studies have shown that PBDEs induce neurotoxic effects in vivo and apoptosis in vitro. However, the signaling mechanisms responsible for these events are still unclear. In this study, we investigated the action of a commercial mixture of PBDEs (pentabrominated diphenyl ether, DE-71) on a human neuroblastoma cell line, SK-N-SH. A cell viability test showed a dose-dependent increase in lactate dehydrogenase leakage and 3-(4,5-dimethylthia-zol-2-yl)-2,5-diphenyl-tetrazolium bromide reduction. Cell apoptosis was observed through morphological examination, and DNA degradation in the cell cycle and cell apoptosis were demonstrated using flow cytometry and DNA laddering. The formation of reactive oxygen species was not observed, but DE-71 was found to significantly induce caspase-3, -8, and -9 activity, which suggests that apoptosis is not induced by oxidative stress but via a caspase-dependent pathway. We further investigated the intracellular calcium ([Ca2+](i)) levels using flow cytometry and observed an increase in the intracellular Ca2+ concentration with a time-dependent trend. We also found that the N-methyl d-aspartate (NMDA) receptor antagonist MK801 (3 mu M) significantly reduced DE-71-induced cell apoptosis. The results of a Western blotting test demonstrated that DE-71 treatment increases the level of Bax translocation to the mitochondria in a dose-dependent fashion and stimulates the release of cytochrome c (Cyt c) from the mitochondria into the cytoplasm. Overall, our results indicate that DE-71 induces the apoptosis of ([Ca2+](i)) in SK-N-SH cells via Bax insertion, Cyt c release in the mitochondria, and the caspase activation pathway.

Molecular identification and expression analysis of natural resistance associated macrophage protein (Nramp) cDNA from Japanese flounder (Paralichthys olivaceus)

Natural resistance associated macrophage protein (Nramp) controls partially innate resistance to intracellular parasites. Its function is to enhance the ability of macrophages to kill pathogens. However, little is known about the structure and function of Nramp in lower vertebrates such as teleosts. We have recently isolated a cDNA encoding Nramp from Japanese flounder (Paratichthys olivaceus). The full-length cDNA of the Nramp is 3066 bp in length, including 224 bp 5' terminal UTR, 1662 bp encoding region and 1180 bp 3' terminal UTR. The 1662-nt open reading frame was found to code for a protein with 554 amino acid residues. Comparison of amino acid sequence indicated that Japanese flounder Nramp consists of 12 transmembrane (TM) domains. A consensus transport motif (CTM) containing 20 residues was observed between transmembrane domains 8 and 9. The deduced amino acid sequence of Japanese flounder had 77.30%, 82.71%, 82.67%, 79.64%, 80.72%, 90.97%, 91.16%, 60.14%, 71.48%, 61.69%, 72.37% identity with that of rainbow trout Nramp alpha and beta, channel catfish Nramp, fathead minnow Nramp, common carp Nramp, striped sea bass Nramp, red sea bream Nramp, mouse Nramp 1 and 2, human Nramp 1 and 2, respectively. RT-PCR indicated that Nramp transcripts were highly abundant in spleen, head kidney, abundant in intestine, liver and gill, and less abundant in heart. The level of Nramp mRNA in embryos gradually increases during embryogenesis from 4 h (8 cell stage) to 80 h (hatched stage) after fertilization. (c) 2005 Elsevier Ltd. All rights reserved.

Mode Characteristics for Square Resonators With a Metal Confinement Layer

Microsquare resonators laterally confined by SiO2/Au/air multilayer structure are investigated by light ray method with reflection phase-shift of the multiple layers and two-dimensional (2-D) finite-difference time-domain (FDTD) technique. The reflectivity and phase shift of the mode light ray on the sides of the square resonator with the semiconductor/SiO2/Au/air multilayer structure are calculated for TE and TM modes by transfer matrix method. Based on the reflection phase shift and the reflectivity, the mode wavelength and factor are calculated by the resonant condition and the mirror loss, which are in agreement well with that obtained by the FDTD simulation. We find that the mode factor increases greatly with the increase of the SiO2 layer thickness, especially as d < 0.3 mu m. For the square resonator with side length 2 mu m and refractive index 3.2, anticrossing mode couplings are found for confined TE modes at wavelength about 1.6 mu m at d = 0.11 mu m, and confined TM modes at d = 0.71 mu m, respectively.

基于TM模激射的圆柱形结构的微盘激光器

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Comparison of Q-factors between TE and TM modes in 3-D microsquares by FDTD simulation

Mode characteristics of three-dimensional (3-D) microsquare resonators are investigated by finite-difference time-domain (FDTD) simulation for the transverse electric (TE)-like and the transverse magnetic (TM)-like modes. For a pillar microsquare with a side length of 2 pin in air, we have Q-factors about 5 X. 103 for TM-like modes at the wavelength of 1550 run, which are one order larger than those of TE-like modes, as vertical refractive index distribution is 3.17/3.4/3.17 and the cororresponding center layer thickness is 0.2 mu m. The mode field patterns show that TM-like modes have much weaker vertical radiation coupling loss than TE-like modes. TM-like modes can have high Q-factors in a microsquare with weak vertical field confinement.

An improved TM method for full two-port calibration of the asymmetric test fixtures

Three known standards, including at least one transmission standard, are normally required for the full two-port calibration of test fixtures. Based on the triple-through method, a new general-purpose calibration procedure using only one known reflection standard is proposed in this paper. The experimental results show that our method call provide a simple and accurate approach to fall two-port calibration of the asymmetric test fixtures. (c) 2005 Wiley Periodicals, Inc.

High-Q TM whispering-gallery modes in three-dimensional microcylinders

We present a generation condition for realizing high-Q TM whispering-gallery modes (WGMs) in semiconductor microcylinders. For microcylinders with symmetry or weak asymmetry vertical waveguiding, we show that TM WGMs can have a high Q factor, with the magnitude of 10(4) at the radius of the microcylinder of 1 mu m, by three-dimensional numerical simulation. The Q factor of TE WGMs is much less than that of TM WGMs in the semiconductor microcylinders due to a vertical radiation loss caused by mode coupling with the vertical propagating mode. The results open up a possible application of TM WGMs in semiconductor microcylinders for efficient current injection microlasers and single photon sources.