Ecological applications of multilevel analysis of variance

A Bayesian representation of the analysis of variance by A. Gelman is introduced with ecological examples. These examples demonstrate typical situations encountered in ecological studies. Compared to conventional methods, the multilevel approach is more flexible in model formulation, easier to set up, and easier to present. Because the emphasis is on estimation, multilevel models are more informative than the results from a significance test. The improved capacity is largely due to the changed computation methods. In our examples, we show that (1) the multilevel model is able to discern a treatment effect that is smaller than the conventional approach can detect, (2) the graphical presentation associated with the multilevel method is more informative, and (3) the multilevel model can incorporate all sources of uncertainty to accurately describe the true relationship between the outcome and potential predictors.     

吉林西部农业生态环境问题及对策

在自然因素和人为因素的影响下,吉林西部农业生态环境问题日益突出,土地退化严重,直接表现为“三化”(即土地盐碱化、草原退化和土地沙化)。盐碱地面积已增至160.69104 hm2,与50年代相比,盐碱地面积增加52.79104 hm2,平均每年增加1.35104 hm2,年递增率1.3%;建国初期,嫩平原吉林省西部草地面积252.9104 hm2,到了1999年,草地面积仅为122.3104 hm2,年递减率约2.6%,而且草原的质量也在下降。目前,沙地面积68.6104 hm2,土地沙化局面已基本控制。文章系统分析农业生态环境恶化的原因和驱动机制,提出综合防治对策和措施。     

高速公路绿化综合效益评价体系

高速公路绿化效益的高低是衡量绿化工程质量优劣的关键因素,而缺乏成熟、规范的高速公路绿化综合效益评价体系是导致高速公路绿化失败的主要原因。通过对现有绿化效益评价方法进行总结与分析,发现层次分析法(AHP)是评价高速公路绿化综合效益科学合理的方法。本研究拟采用AHP法,采用专家调查论证的方式,建立了评价指标体系及各层次相关元素的权重值,构建绿化效益评价的基础模型,实现对不同高速公路、同一高速公路的不同路域、不同植物配置模式等的综合绿化效益的评价及比较,促进绿化质量的提高。使高速公路绿化工程建设管理走向规范化。     

宁夏贺兰山自然保护区油松林碳储量及分布格局

森林保护对减缓全球变暖有着重要意义。不同森林生态系统由于其所处地理位置不同,气候、土壤、物种构成差异很大,因此其碳汇功能也各不相同,油松是中国北方重要的森林类型之一,为了摸清贺兰山自然保护区森林碳储量,本文通过实地调查取样和室内实验测定的方法,于2011—2012年期间对宁夏贺兰山自然保护区油松林碳储量进行了取样测定,估算了其碳储量。结果表明：油松单株平均含碳率为51．91％,高于国内其他地区的阔叶树种及灌木的含碳率;经估算贺兰山油松林总有机碳储量为13．39kg.m^-2,其中立木碳储量为2．98kg．m^-2,地被层有机碳碳储量为0．86kg·m^-2,土壤层有机碳储量为9．55kg．m^-2,土壤碳储量占林分碳储量的70％以上,是油松林有机碳的主要储存库。总体来看,针叶林的固碳能力要高于阔叶林,在营造固碳林时应优先考虑针叶树种。从分布格局来看,东经105．80°～106．15°,北纬38．36°～39．00°,海拔2000～2400m的区域是油松林的主要分布区域,也是贺兰山森林有机碳的主要分布区,该区域是保护区碳平衡研究和碳汇管理应该关注的重点区域。     

森林生态系统中土壤呼吸研究进展

土壤呼吸是土壤微生物活性和土壤肥力的一个重要指标，是土壤碳流通的一个重要过程，也是陆地生态系统碳循环的一个关键部分，对研究全球变化有非常重要影响。文章综述了森林生态系统土壤呼吸的各种测量方法，比较了静态气室法和动态气室法的优缺点，认为动态红外气体分析法是最可靠的方法之一；探讨了影响土壤呼吸速率的各种因素，指出在各生物和非生物因素中，温度对土壤呼吸的影响最大；最后提出了土壤呼吸研究过程中存在的一些问题及今后的发展方向。     

Biochemical genetics of the sea anemone Bunodosoma cavernata and the zoogeography of the Gulf of Mexico

Much of the inshore fauna of the Gulf of Mexico has a disjunct distribution around the tip of Florida. Some of this fauna is composed of temperate, Carolinian species whose separation is thought to be due to warming after the last glacial period. Other species with this distribution are more eurythermal, and the vicariant event affecting them is unclear. One such eurythermal species is the sea anemone Bunodosoma cavernata. Using the genetic distance between Gulf and Atlantic populations of this species as an estimator of time since divergence, it is concluded that the vicariant event was the emergence of Florida in the Pliocene. It is suggested that the present Gulf Stream system maintains the separation of these populations.     

On the nature and role of protein constituents of the cuticle of crustaceans in relation to permeability of the cuticle

The chemical composition of the cuticle in regions which are permeable and impermeable to water in 4 crustaceans (Ocypode platytarsis, Metapenaeus monoceros, Emerita asiatica, Ligia exotica) was investigated, with special reference to the protein components. It was found that the cuticle which is permeable lacks the outer epicuticle or the entire epicuticle compared to the cuticle in the impermeable regions. The permeable cuticle is distinguished by the absence of a fuchsinophil protein, which is a precursor of tanning. Permeability of the cuticle is also associated with the presence of a simple protein, positive to the biuret test, and with a protein containing sulphydryl groups. It is considered that the cuticle protein may play a role in conferring permeability properties to the cuticle itself.     

Use of Approximate Inference in an Index of Completeness of Biological Inventories

Abstract:  To assess the completeness of a floristic or faunal inventory, one may use the ratio of the observed number of species to the "true number" of species ( C ). If the inventory is complete , C = 1. The estimate of the true number can be obtained from accumulation curves, nonparametric methods, or other techniques. We devised a simple method for computing confidence intervals (CI) for C and for evaluating the null hypothesis that the inventory is complete. The method is based on the assumptions that an estimate of the variance of the true number of species is known and that the distribution of the estimator of the true number of species is approximately normal. We applied our method to bird inventories in the Balsas Basin of Mexico. The completeness index for subtransects were lower (84.0, 85.4, and 89.9%) than for the whole transect (91.6%) (all significantly different from 100%). Thus, these particular inventories were incomplete at 2 spatial resolutions. Our method of estimating CI for C can be used to estimate species richness obtained from databases of different sites or to test the null hypothesis that an inventory derived from a database is complete.     

盐碱地农-渔开发对土壤环境的影响

在东北苏打盐碱地进行了稻-鱼-苇-蒲开发试验,并探讨了该模式对盐碱土壤环境的影响。结果表明,开发后土壤有机质含量增加96.8%(平均值,以下同),盐分含量下降43.6%,全量和速效N、P、K质量分数分别增加142.8%和188.2%;阳离子交换量、盐基总量分别增加8.21%及27.71%;土壤腐殖质以富里酸为主,w(HA)/w(FA)比值提高36.15%;养鱼稻田的土壤微生物总量明显高于未养鱼田(P<0.01);优势种为放线菌。土壤酶活性进一步加强。系统废水的盐分质量浓度降至1.0 g/L左右,碱浓度低于水源(7.0~10.0 mmol/L)。该模式不会造成土壤次生盐碱化。     

豪猪消化系统的解剖研究

为了了解豪猪的消化生理,为豪猪的人工饲养技术研究提供基础依据,以达到高效饲养豪猪的目的,笔者对豪猪的消化器官进行了系统解剖研究.结果表明:豪猪的胃为单室胃.盲肠很发达,这与其能够消化植物纤维有关.豪猪肝脏很发达,其重量为402 g,是其体重的4.59%,肝脏分叶多而明显.     

6种观赏植物吸收甲醛能力比较研究

城市住宅的室内空气污染十分严重,甲醛已经成为中国目前室内空气中的首要污染物.在已有的报道中,盆栽观赏植物吸收甲醛的效果并未排除盆土的净化能力,由此植物净化效果显然缺乏科学性.选用6种常用室内观赏植物,将盆土与茎叶部分隔开,放入自行研制的甲醛熏蒸箱中,对植物进行熏蒸实验.测得熏蒸前后甲醛的变化量和植物叶面积,以净吸收率及单位叶面积甲醛减少量来比较6种植物吸收甲醛能力的大小.主要结论如下:(1)甲醛质量浓度是国际标准(0.08 mg·m~(-3))23倍情况下,6种观赏植物均能吸收空气中的甲醛,且因种类不同吸收能力大小不一.吸收甲醛能力排序为:广东万年青(Aglaonema modestum)>绿萝(Epipremnum aureum)>垂叶榕(Ficus benjamina)>虎尾兰(Sansevieria trifasciata)>龟背竹(Monstera deliciosa)>四季秋海棠(Begonia semperflorens-hybr.).单位叶面积植物吸收甲醛量依次为:广东万年青绿萝>虎尾兰>龟背竹>垂叶榕>四季秋海棠.(2)甲醛质量浓度是国际标准(0.08mg·m~(-3))57倍情况下,6种观赏植物吸收甲醛能力排序为:垂叶榕>虎尾兰>绿萝>广东万年青>龟背竹>四季秋海棠.单位叶面积植物吸收甲醛量依次为:虎尾兰>垂叶榕>龟背竹>广东万年青>绿萝>四季秋海棠.(3)根据净吸收率及单位叶面积吸收甲醛量的差异,将植物的吸收能力分为两类,吸收甲醛能力较强的植物有:广东万年青、绿萝、虎尾兰、龟背竹、垂叶榕(与空白组相比有显著性差异(P<0.05));较低的植物有:四季秋海棠(与空白组相比无显著性差异).     

基因芯片在鼻咽癌研究中的应用

鼻咽癌是我国南方及东南亚地区常见的恶性肿瘤,严重威胁人类健康．鼻咽癌的发生、发展是一个多因素、多基因和多阶段的过程,其基因的异常要远远先于形态改变．进行鼻咽癌发生发展中分子机制及相关基因的研究,为,临床上寻找病因、早期诊断及病理分型等方面提供重要的理论依据．基因芯片作为近几年发展起来的一项新兴分子生物技术,具有高通量、准确、高效信息检测的特点,能够研究细胞内所有基因的表达谱,同时获得成千上万个基因活化的模式,为肿瘤临床诊断和治疗提供了强有力的工具．参15．     

碱性矿化水灌溉的淋洗分数

耐盐碱试验表明,在生育期内,小麦耐盐能力强于玉米,而耐碱能力弱于玉米.利用0.5-3.5 g/L的碱性矿化水灌溉时,淋洗分数约为4.4%～7.5%.相应地,需要增加的补水量小麦地为3181～     

城市住区空气负离子浓度时空变化及空气质量评价--以合肥市为例

以夏热冬冷地区合肥市为研究区域,从建筑布局、空间形态、建筑密度、交通路网、植物绿化等方面综合考虑城市住区的不同环境特征,选择12个样点进行实地观测,于2013年8至2014年1月进行了空气离子浓度、风速、温度、相对湿度等指标的实地测定,并对数据进行筛选分析得出结果,空气负离子浓度随季节变化较为明显,夏季最高,平均浓度约为358/cm3,秋季次之,平均浓度约为338/cm3,冬季最低,平均浓度约为322/cm3。总体看来,上午9：00─10：00和下午14：30─15：30区间空气负离子浓度最高,上午10：30和下午16：00─16：30区间空气负离子浓度相对较低。②自由式布局和具有较明显开敞空间的测试样点空气负离子浓度较高。夏季样点9空气负离子浓度最高,平均浓度为815/cm3;秋季样点12空气负离子浓度最高,平均浓度约为483/cm3;冬季样点9空气负离子浓度最高,平均浓度约为407/cm3。最后运用单极系数和安培空气质量评价指数对住区空气质量进行评价,得出住区环境的空气清洁度以允许和清洁为主,等级多分布在D级和B级。根据这些结果和分析得出以下结论：在不同的季节,住区室外环境的空气负离子浓度变化较为明显,夏季最高,冬季最低。②影响城市住区空气负离子浓度最主要气象因子是风速、温度和相对湿度,其中风速和温度与空气负离子浓度呈现出正相关,而相对湿度则总体趋势不明确。③采取层次丰富的植物结构有利于提高环境的空气负离子浓度。④空气负离子浓度与空气清洁度有着密切关系,不同的环境特征下空气清洁度存在差异。⑤以空气负离子浓度为参考标准指导并优化住区建筑布局,不仅有利于提高住区人居环境质量评价工作的科学管理水平,同时对于提高居民的健康水平和营造健康舒适的居住环境具有重要的?     

Waves of intermediate length through an array of vertical cylinders

We report a semi-analytical theory of wave propagation through a vegetated water. Our aim is to construct a mathematical model for waves propagating through a lattice-like array of vertical cylinders, where the macro-scale variation of waves is derived from the dynamics in the micro-scale cells. Assuming infinitesimal waves, periodic lattice configuration, and strong contrast between the lattice spacing and the typical wavelength, the perturbation theory of homogenization (multiple scales) is used to derive the effective equations governing the macro-scale wave dynamics. The constitutive coefficients are computed from the solution of micro-scale boundary-value problem for a finite number of unit cells. Eddy viscosity in a unit cell is determined by balancing the time-averaged rate of dissipation and the rate of work done by wave force on the forest at a finite number of macro stations. While the spirit is similar to RANS scheme, less computational effort is needed. Using one fitting parameter, the theory is used to simulate three existing experiments with encouraging results. Limitations of the present theory are also pointed out.     

Sensitivity analysis of the asymptotic behavior of a model for the environmental movement of radionuclides

The asymptotic behavior of a linear compartment model for the environmental movement of radionuclides is investigated. Here, the expression asymptotic behavior is used to designate the behavior of q(t) as t → ∞, where q is the solution of a vector differential equation of the form dq/dt = h + Kq. The asymptotic behavior of such equations is described. For the model and conditions under consideration, each element of q converges monotonically to a steady-state value. A hydrologic system is defined and used to illustrate this behavior. An approach to sensitivity analysis employing Latin hypercube sampling, rank transformations and stepwise regression is presented and then applied to this system. A total of 20 independent variables is introduced and the following dependent variables are investigated for the various components of the system: amount of radionuclide present at steady state. concentration of radionuclide at steady state, and time required to reach 90% of steady state. Finally, an application of asymptotic behavior in the analysis of a hypothetical site for the geologic isolation of high-level radioactive waste is described and a brief discussion of differential sensitivity analysis is given.     

论人的个体发展与整体发展的统一

本文论述了人的全面发展是个体发展与整体发展的统一，个体的发展是整体发展的基础，整体发展是个体发展的必然结果．提出了人类通过实践、创新、发展生产力，提高人的素质，促进人的全面发展．     

Distribution of a population of annelid polychaetes in the “trottoir” of the midlittoral zone on the coast of North-East Spain,Western Mediterranean

The discharge and mode of action of the microbasic mastigophores (b-Rhabdoids) of Anemonia sulcata Pennant (Anthozoa) tentacles were examined using light and electron microscopical techniques. The statistical analysis of different morphological parameters of 100 nematocysts before and after their complete discharge revealed four different phases in the process of discharge. The first phase consists of the opening of the three opercular flaps. The second phase is characterized by the extrusion of the shaft. Osmotic pressure generated by the nematocyst propagates the extremely fast shaft discharge. The third phase, the evagination of the long tubule, is propagated by intrinsic mechanical forces stored in the tubule's twists and coils. During the process of evagination the tubule length increases by 95%, its circumference by 17%. Its forward motion is produced by the dilatation of its circumference and undoing of its twists. This motion is supported by the pressure which is generated by the hydration of the capsular matrix. The fourth phase consists in the extrusion of soluble capsular material at the tip of the evaginated tubule. During discharge the net volume of the nematocyst increases by 182%. This expansion is only possible if a high osmotic pressure is generated within the cyst. The extrusion of the shaft is the crucial phase in the discharge of the microbasic mastigophores, because without the puncture produced by the shaft the tubule is not able to overcome even surfaces of low viscosity media. The function of these tentacular nematocysts is the mechanical capture of prey organisms and, most probably, the introduction of unknown toxins into the latter.     

The value of information on the response function of crops to soil salinity

The expected profitability to farmers from acquiring additional information on the biological response function of crop yield to soil salinity is investigated. First, a switching regression approach to estimate piecewise linear response function with critical threshold level is presented. Then, an optimization irrigation model is developed, aimed at determining the optimal use of irrigation water for soil leaching. Finally, a loss function is defined, the expected value of sample information is calculated and the optimal number of additional needed observations is determined. At each stage, an empirical analysis, using data from potato field experiments in Israel, is presented.     

The adaptive value of larval behavior of a colonial ascidian

Didemnum candidum Savigny, 1816 is an abundant member of the fouling community encrusting docks in Pearl Harbor, Hawaii. In the laboratory, larvae of D. candidum are positively phototactic upon release, but become indifferent to the direction of light prior to settlement. In both the laboratory and the field, settlement is most abundant on shaded, downward-facing surfaces, the location where juvenile survival is greatest. The colonial ascidians Diplosoma listerianum Milne-Edwards, 1842 and Diplosoma sp. also settle abundantly on shaded undersurfaces in the field. Juvenile survival of the Diplosoma species is not affected by exposure to direct light, while survival is greatest on downward-facing surfaces. For Didemnum candidum, light is an important environmental cue used by larvae to locate settlement sites on shaded, downward-facing surfaces where juvenile survival is enhanced.