1988-2013年基于BP神经网络的植被叶面积指数遥感定量反演

叶面积指数（Leaf Area Index,LAI）高度综合了植被水平覆盖状况和垂直结构,以及枯枝落叶层厚薄和地下生物量多少,是植被影响土壤侵蚀的主要方面。区域尺度的时间序列叶面积指数揭示了区域土壤侵蚀的演化过程。因此,及时准确地掌握区域尺度上长时间序列的植被LAI,对研究土壤侵蚀动态变化与植被的关系至关重要。选择南京市1988-2013年10期遥感影像,基于反向传播（Back Propagation,BP）神经网络构建LAI反演模型,进行了长时间序列的叶面积指数反演。结合2009和2010年LAI实测值,验证与探讨了该模型的评价精度与适应性。结果表明：（1）该模型拟合度较高,2009和2010年平均相对误差、均方根误差、相关系数分别是0.2395和0.2174,0.2962和0.2581,0.7713和0.6844,各项精度评价指标均较好;（2）统计分析去除耕地后全市LAI变化,低植被覆盖（LAI<2）面积不断增加,高植被覆盖区（LAI>3）面积先减少后增加,耕地面积不断减少,符合南京市的发展变化规律;（3）主城区LAI年际变化与其他学者得到的南京市植被盖度变化趋势一致,反演结果的时序性较高。本文提出的基于反向传播神经网络模型反演长时间序列LAI是可行的,为区域尺度土壤侵蚀定量遥感监测提供新途径。     

Plasma N-glycome composition associates with chronic low back pain

Background

Low back pain (LBP) is the symptom of a group of syndromes with heterogeneous underlying mechanisms and molecular pathologies, making treatment selection and patient prognosis very challenging. Moreover, symptoms and prognosis of LBP are influenced by age, gender, occupation, habits, and psychological factors. LBP may be characterized by an underlying inflammatory process. Previous studies indicated a connection between inflammatory response and total plasma N-glycosylation. We wanted to identify potential changes in total plasma N-glycosylation pattern connected with chronic low back pain (CLBP), which could give an insight into the pathogenic mechanisms of the disease.

The role of plant species in biomass production and response to elevated CO2 and N

In an experiment that factorially manipulated plant diversity, CO₂, and N, we quantified the effects of the presence of species on assemblage biomass over 10 time points distributed over 5 years. Thirteen of the 16 species planted had statistically significant effects on aboveground and/or belowground biomass. Species differed dramatically in their effects on biomass without any relationship between aboveground and below‐ground effects. Temporal complementarity among species in their effects seasonally, successionally, and in response to a dry summer maintained the diversity–biomass relationships over time and may be the cause behind higher diversity plots having less variation in biomass over time. The response of plant biomass to elevated N, but not CO₂, was at times entirely dependent on the presence of a single species.     

Habitat and landscape factors associated with neotropical waterbird occurrence and richness in wetland fragments

Habitat destruction alters the structure and spatial arrangement of remnants and creates a novel matrix, affecting the structure of biological communities. This study evaluated the contribution of patch, class and landscape level attributes of 42 wetland fragments and surrounding landscapes on the richness, abundance and presence of waterbird species. Twelve monthly censuses identified 55 species––ranging from 3 to 40 among fragments, and a total of 84,286 birds––ranging from 15 to 19,322. Wetland areas varied from 0.2 ha to 145.2 ha. The presence of 37 out of 42 species could be predicted from the structure of the fragments and the landscapes. The most important predictors were the wetland area (22 models), the rice field matrix permeability (13 models), the microhabitat richness (7 models), the wetland connectivity (5 models), and the wetland isolation (5 models). Discriminant analysis showed that fragments richer in species than expected from their areas, are found in landscapes with greater connectivity and matrix permeability than the species-poor fragments. The total area of rice fields was not related to the richness, abundance or presence of waterbirds in the wetlands fragments. The results suggest that the maintenance of the connectivity among fragments and the matrix permeability through rice-fields could be managed to foster the waterbird conservation at the landscape scale.     

The penetration of sodium into the brain following a cisternal injection of sodium chloride with particular emphasis on the area postrema

Summary Following an intracisternal injection of sodium chloride, sodium has been localized in paraventricular and subpial tissues of the posterior fossa by means of the pyroantimonate histochemical technique, with the use of a buffered pyroantimonate medium. The electron dense deposit is present in these tissues within 4 minutes after injection and is found only extracellularly except in the area postrema. This finding supports the contention that sodium is chiefly an extracellular ion and that the cerebrospinal fluid and the extracellular fluid are in equilibrium at these sites. In the area postrema, an intracellular precipitate is noted in the vesicular structures of the atypical astrocytes of this structure and in pinocytic vesicles of the large blood vessels. The intraglial localization of sodium in the area postrema is discussed in relation to a possible function of this structure as a regulator of cerebrospinal fluid ionic content.This work was supported by grant number NB-08549-02 from the National Institute of Neurological Disease and Stroke, Bethesda, Maryland.     

Distribution of monoamine oxidase in the hippocampal region of the guinea pig

Summary 1. The distribution of monoamine oxidase (MAO) within the dentate area, a part of the hippocampal region, has been described for the adult guinea pig.2. The histochemical demonstration of the enzyme was done essentially according to the tryptamine-tetrazolium method of Glenner et al., and the staining reactivity was controlled by complete inhibition with iproniazide.3. Most of the MAO in the dentate area was present in a stratified pattern. Within the molecular layer, a supragranular third reacted heavily, while a more weakly staining superficial layer could be distinguished from an intermediate, still paler lamina. The granular cell bodies were unstained. In the hilus, five layers showing alternating stronger and weaker activity were observed. The distribution of the MAO staining was compared with conventional anatomical subdivision of the dentate region.4. The guinea pig dentate area appears to have a greater amount and more stratified distribution of MAO than the comparable region previously described in the rat.I am indebted to Mrs. E. Kjær Hansen, Mrs. L. Knudsen, Mr. A. Meier, Mr. Th. Nielsen, Mrs. K. Sørensen, and Miss M. Sørensen for skillful technical assistance. This study was supported in part by U.S.P.H.S. Grant NS 07998.     

The “Grey Area” in the Northern Bay of Bengal: A Note on a Functional Cooperative Solution

The judgments in maritime delimitation cases involving Bangladesh and Myanmar (2012) and between Bangladesh and India (2014) have resulted in a “Grey Area” in the northern Bay of Bengal involving intersecting and overlapping rights and responsibilities in terms of the exclusive economic zone (EEZ) and continental shelf regimes. This article seeks to identify a functional solution for this Grey Area.     

Implementation of a small-scale “no-use zone” policy in a reef ecosystem: Eilat’s reef-lagoon six years later

 A small-scale, “no-use zone policy” has been implemented since 1992 at Eilat’s Coral Nature Reserve (Northern Red Sea). Six years later, the status of this closed-to-the-public reef area was compared to two nearby open-to-the-public sites, by evaluating populations of the scleractinian coral Stylophora pistillata in the strolling zone (0.5–1.5 m depth). Results from the open sites show that: (1) Live coral cover was three times lower than at the closed site; (2) numbers of small colonies (recruits) were significantly higher than in the closed site, while numbers of medium and large size colonies (geometric mean radius, rˉ>4.1 cm) per m² were significantly lower; (3) maximum rˉ was almost half than that in the closed site (9.6 cm versus 16.7 cm); (4) average number of broken colonies was three times higher than in the closed site; (5) significantly fewer colonies were partially dead. The latter result may reflect senescence processes in the large colonies of the closed site. Although colony breakage is reduced, it appears that the “no-use zone” policy is not sufficient for protecting small reef areas. The intense exploitation of Eilat’s coral reef by the tourist industry requires’ in addition to the conventional protective measures, the initiation of novel management solutions such as reef restoration by sexual and asexual recruits. Accepted: 11 August 1999     

毛乌素沙地若干植物光合作用,蒸腾作用和水分利用效率种间及生境间差异

报道了内蒙古毛乌素沙地不同生境下66种不同科属植物的光合作用、蒸腾作用和水分利用效率特征。这几种生境包括流动沙丘、固定沙丘、滩地和湿地,所分布的植物与表现的生理生态特征不同。研究结果表明:藜科、禾本科、豆科等具有C4光合碳同化途径或具固氮能力的植物具有较高的光合能力,其净光合速率20～30μmolCO2·m-2·s-1;而松柏科的常绿植物具最低的光合速率,0～5μmolCO2·m-2·s-1。菊科、玄参科、禾本科等具C3途径和无固氮能力的植物蒸腾作用最高,为20～30mmolH2O·m-2·s-1;松柏科、杨柳科和菊科的个别植物蒸腾速率很低,为0～5mmolH2O·m-2·s-1。豆科、禾本科和藜科中具C4光合途径或固氮能力的一些植物(灌木或草本植物)具有较高的水分利用效率。然而,植物的这些生理生态指标随不同季节和生境表现出不同的特点,在晚夏季所测的净光合速率、蒸腾速率分别比初夏季高26%和40%,而水分利用效率下降12%。从总体趋势来看,随着生境沿着由湿到干的不同水分供应等级,如从湿地、滩地、固定沙丘至流动沙丘,光合作用和蒸腾作用呈现减弱的趋势,而水分利用效率则呈现升高的趋势