Pterospathodus eopennatus(牙形刺)带的确认与志留系纱帽组的时代及相关地层的对比

Mannik(1998)建立的牙形刺Pterospathodus eopennatus带在华南普遍存在,以前鉴定的P.celloni带的地层多数都要归入P.eopennatus带,包括秀山组的上段;P.celloni带的地层主要存在于宁强组神宣驿段的中上部,分布有限。扬子地台上秀山组的顶界在各剖面上不等时。秭归纱帽组顶部的灰岩层的时代是Telychian早期P.eopennatus带上部,可能延伸到P.a.angulatus带。溶溪组、马脚冲组的地层可能应归入Aeronian阶而不是Telychian阶。     

A revision of the Nasa ranunculifolia group (Nasa ser. Grandiflorae pro parte,Loasaceae)

The monophyletic Nasa ranunculifolia group (Nasa ser. Grandiflorae pro parte) is revised on the basis of extensive field studies and a revision of copious herbarium material. All species of this group are from the high Andes of Peru and Ecuador (mostly 3000–4300 m). The overall degree of morphological divergence is much lower than in other groups of Nasa and many of the various local ‘races’ are best recognized as ecogeographically isolated subspecies. Thus, six species and 13 subspecies are recognized on the basis of differences in leaf and floral morphology, growth habit, life history and distribution. Nasa ranunculifolia, N. macrantha, N. cymbopetala and N. macrorrhiza are united as subspecies under N. ranunculifolia. An additional five subspecies of N. ranunculifolia are newly described (ssp. pamparomasii, ssp. guzmangoensis, ssp. bolivarensis, ssp. patazensis and ssp. huanucoensis). Nasa rugosa is subdivided into four subspecies, three of them new (ssp. llaqtacochaensis, ssp. gracilipes and ssp. pygmaea). Nasa tulipadiaboli sp. nov. and N. basilica sp. nov. are described as new species. Eight taxa (seven subspecies and one species) are endemic to the Amotape–Huancabamba Zone, and seven of them (six subspecies and one species) are new to science. Only a single species ranges into the Amotape–Huancabamba Zone from the south, underscoring the high levels of endemism (and taxonomic novelty) in this area. Illustrations, distribution maps, a key and diagnoses are given for all taxa recognized. © 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 167 , 47–93.     

Neonatal Subventricular Zone Electroporation

Neural stem cells (NSCs) line the postnatal lateral ventricles and give rise to multiple cell types which include neurons, astrocytes, and ependymal cells¹. Understanding the molecular pathways responsible for NSC self-renewal, commitment, and differentiation is critical for harnessing their unique potential to repair the brain and better understand central nervous system disorders. Previous methods for the manipulation of mammalian systems required the time consuming and expensive endeavor of genetic engineering at the whole animal level². Thus, the vast majority of studies have explored the functions of NSC molecules in vitro or in invertebrates.Here, we demonstrate the simple and rapid technique to manipulate neonatal NPCs that is referred to as neonatal subventricular zone (SVZ) electroporation. Similar techniques were developed a decade ago to study embryonic NSCs and have aided studies on cortical development^3,4 . More recently this was applied to study the postnatal rodent forebrain^5-7. This technique results in robust labeling of SVZ NSCs and their progeny. Thus, postnatal SVZ electroporation provides a cost and time effective alternative for mammalian NSC genetic engineering.     

Equivalence or Selection: A Distribution-Free Approach

Using a distribution-free approach, a modification of the usual procedure for selecting the better of two treatments is presented. Here the possibility of no selection when the treatments appear to be ‘equivalent’ is allowed. The sample size and the constant needed to implement the proposed procedure are determined by controlling the probabilities of a correct selection and a wrong selection when the two treatments are not equivalent.     

鄱阳湖生态经济区植被固碳研究

对鄱阳湖生态经济区的植被固碳研究表明,该区森林碳储量364.3×10⁶ t,草地植被固碳量90.65×10⁴ t,水稻固碳量18.51×10⁶ t,其他农作物固碳量20.64×10⁶ t;鄱阳湖湿地固定CO₂量为609 120 t/a。因此,建议对现有森林进行科学抚育与合理采伐,进而形成合理的树种结构、林龄结构与林层结构,提高森林生态系统的稳定性与碳汇能力;运用保护性耕作、灌溉节水和合理施肥技术,培育新型氮素高效利用的农作物新品种,提高光合作用率,从而提高该区农作物的固碳能力;进行合理放牧和草地资源生态监测,严格控制养殖数量和规模,实现草地生态系统减少与固定CO₂的重要功能;严禁围湖造田,健全水域环境监测网络,保护湿地生态功能。     

连云港海岸岩相潮间带海葵的多样性及生物量

研究了连云港海岸岩相潮间带海葵的分布多样性及生物量。结果表明,海葵的水平分布多样性和生物量与盐度、干扰、海岸开敞度有关;垂直分布多样性和生物量与种类抗干燥度、浪击度、潮汐和食物有关;岩石的空间异质性对海葵的分布多样性具有一定的影响。     

Changes in plant species diversity along a chronosequence of vegetation restoration in the humid evergreen broad-leaved forest in the Rainy Zone of West China

Plant species diversity has been recognized as one of the vital attributes for assessing vegetation restoration. Changes in the diversity may be related to different stages of succession. In this study, 54 sites of humid, evergreen, broad-leaved forest were selected in the Rainy Zone of West China. A chronosequence of the sites was used to study the successive patterns of the diversity in the forest that had undergone natural regeneration for 5 to 350 years and to test the hypothesis that the diversity is maximized in mid-succession. Data were collected simultaneously at different stages of succession, and four α-diversity indices (species richness, Margalef index, Shannon-Wiener index, Pielou Evenness index) and two β-diversity indices (Whittaker index, Sørensen’s index) were calculated for each stratum in each plot. A total of 394 vascular plant species were recorded. From the β-diversity indices, the forest succession may be divided into the early-successional stage (before 50 years), mid-successional stage (from 50 to 300 years), and late-successional stage (after 300 years). In this community, the species diversity and richness were found to be the greatest at the mid-successional stage, followed by the late- and early-successional stages. The results of regression analysis indicated that the richness and Margalef index peaked around the 175th and 165th year, respectively. Shannon-Wiener index values also appeared to follow an approximately humped pattern of succession and were maximal around the 100th year. However, the species evenness did not show any significant relationship with successional age. Our results demonstrate (1) forest restoration is a long-term process and the formation of climax forest requires at least 300 years and (2) the forest has a strong capacity for restoration. Our results also suggest Lindera limprichitii and Machilus pingii as ideal tree species for afforestation because of their wide niche.     

环境价值评估中的WTP值和WTA值测算与非对称性——以广西北部湾经济区滨海生态环境保护为例

基于广西北部湾经济区4城市940位受访者的问卷调查结果,采用 logit模型对这些受访者保护滨海优良生态环境的最大支付意愿(WTP)和接受的最小赔偿意愿(WTA)进行了测算,其结果显示:5年内的WTP期望值为450.17元 a^-1 户^-1, WTA期望值为5772.71元 a^-1 户^-1,WTA/WTP比值为12.8倍,表现出非常明显的非对称性特征,但基本符合国内外在该领域的实证结果。通过对同一受访者支付意愿和接受赔偿意愿的交叉分析,可知WTP和WTA同时不为0的受访者有276人,占总抽样人次的29.4%,其WTA/WTP比值为12.54,与logit模型测算的WTA/WTP比值非常接近,从一侧面更准确地反映了这一群体对环境物品估值的差异性,同时也可反映logit模型测算的可靠性。基于行为经济学的前景理论分析,发现研究中的受访者存在厌恶损失效应、框架效应和对预期不确定风险的规避行为,同时受访者还存在明显的搭便车行为。通过对受访者的情境因素分析,发现其中2个情境因素对受访者选择WTP和WTA具有较大影响,主要表现为惩罚效应,尤其是经济收入满意度情境因素对受访者的经济行为影响显著,而另3个情境因素未表现出有规律性的影响。     

新兴海岛型城市建设引发的生态变化的遥感分析——以福建平潭综合实验区为例

福建省平潭岛于2010年被正式确立为“福建省平潭综合实验区”,由此引发了新兴海岛型城市的建设高潮.本研究利用遥感生态指数(RSEI),基于2007年Landsat-5影像和2013年Landsat-8影像,分析了平潭综合实验区建设初期的生态状况及其时空变化趋势和变化原因.结果表明： 研究期间,作为生态脆弱的海岛,平潭岛的生态状况整体处于中等水平,在综合实验区建设初期(2007-2013年)有进一步下降的态势,RSEI值从2007年的0.511下降至2013年的0.450,降幅达14%;占全岛面积约36.5%区域的生态状况趋于退化,且主要发生在中部和西南部地区.究其原因主要是由于综合实验区建设带来的大面积成片开发,使得岛内原本不多的植被遭到进一步破坏.平潭岛在综合试验区建设中应及时制定并落实科学有效的生态保护措施,以遏制其生态质量下滑的趋势.     

Relationship between innervation zone width and mean muscle fiber conduction velocity during a sustained isometric contraction

Objectives:

To examine the relationship between the biceps brachii muscle innervation zone (IZ) width and the mean muscle fiber conduction velocity (MFCV) during a sustained isometric contraction.

Methods:

Fifteen healthy men performed a sustained isometric elbow flexion exercise at their 60% maximal voluntary contraction (MVC) until they could not maintain the target force. Mean MFCV was estimated through multichannel surface electromyographic recordings from a linear electrode array. Before exercise, IZ width was quantified. Separate non-parametric one-way analyses of variance (ANOVAs) were used to examine whether there was a difference in each mean MFCV variable among groups with different IZ width. In addition, separate bivariate correlations were also performed to examine the relationships between the IZ width and the mean MFCV variables during the fatiguing exercise.

Results:

There was a significant difference in the percent decline of mean MFCV (%ΔMFCV) among groups with different IZ width (χ² (3)=11.571, p=0.009). In addition, there was also a significant positive relationship between the IZ width and the %ΔMFCV (Kendall’s tau= 0.807; p<0.001).

Conclusions:

We believe that such relationship is likely influenced by both muscle fiber size and the muscle fiber type composition.