管网雨水补给河道用水的人工湿地水质净化流程研究

中国北方部分地区水资源短缺,河道干涸,但夏季雨水资源潜力丰富。虽径流受到一定污染,但较于生活污水和工业废水,其污染程度更低,成分更简单。雨水通过低运行成本的人工湿地净化系统,可以实现较好的净化效果,满足河道景观需求和生态补水。城市管网雨水承载能力过重的城市边缘区,建设更新过程中进行雨污分流制度,更适于采用人工水质净化的方式将城市雨水管网中的雨水进行就近消纳,减轻城市雨水管网压力,并利用表面负荷率（ALR）来确定并校核人工湿地面积。在综合现在人工水质净化主流程预处理单元、人工湿地单元和消毒存储单元3个环节的基础上,以低运营成本、低管理成本、最优净水量为指向,引入物联网技术智能管控系统,行程具有能控制各级出水水质监测、多级管控、净水生态功能与游览景观功能相结合等多重优点的人工水质净化全流程,达到符合河道水质标准的净化效果。该流程为缓解北方城镇河道缺水现状、解决城市雨洪问题提供新思路。     

The effects of different PMSG doses on estrus behavior and pregnancy rate in Angora goats

Artificial insemination protocols depend on efficient behavioral estrus detection and insemination time in Angora goat. Therefore, we aim to determine the accuracy of an estrus scoring system in Angora goats with different PMSG doses during the breeding season. Does (n: 260) were randomly divided into three groups: group-1 (n: 93), group-2 (n: 85) and group-3 (n: 82). All animals received an intravaginal sponge on day 0 for 11 days, and on the day of sponge insertion 150 μg prostaglandin F2Α was administered. Pregnant mare’s serum gonadotropin was injected 300, 400 and 500 IU intramuscularly 24 h before sponge removal to groups 1, 2 and 3, respectively. Estrus signs were detected with a teaser buck, 24 h after sponge removal according to a visual scoring system. Artificial insemination was performed with 0.25 ml fresh diluted semen at 43 to 45 h after sponge removal. Differences were observed within PMSG groups in terms of standing, tail wagging, courtship behavior, vaginal discharge and vaginal hyperemia (P<0.001). Nevertheless, the most accurate indicators of estrus that result in pregnancy were tail wagging and courtship behavior followed by standing estrus (P<0.05). According to the results obtained, 300 IU PMSG dose is sufficient, both to inseminate at a fixed time (43 to 45 h after sponge removal) and to record the estrus behavior by teaser male 24 h after sponge removal. Higher PMSG doses (400 to 500 IU) altered the timing of ovulation; specifically, 500 IU dose shortened the duration of estrus behaviors. In conclusion, even though the different doses of PMSG displayed similar effects on estrus synchronization and pregnancy rates, we concluded that tail wagging, courtship behavior and standing heat are the most reliable estrus signs for artificial insemination in Angora goat.     

枸杞新品系NQ-2开花生物学研究

为探讨枸杞新品系NQ-2纯系种植结实率低的原因,采用TTC法、联苯胺—过氧化氢法、花粉—胚珠比、杂交指数和套袋试验等方法,对NQ-2花粉活力、柱头可授性及繁育系统等进行了研究。结果表明:NQ-2单花花期为3~4 d,花后8 h散粉结束,开花当天花粉活力最高,花粉寿命可持续9 d以上;开花前一天柱头已具可授性,开花第1天柱头可授性最强,开花第3天柱头基本失去可授性;枸杞新品系NQ-2平均花粉-胚珠比8615,OC I=4,结合人工授粉实验结果确定其繁育系统为专性异交。自交不亲和是导致NQ-2纯系种植落花落果结实率低的主要原因。     

Comparisons of population density and genetic diversity in artificial and wild populations of an arborescent coral,Acropora yongei: implications for the efficacy of “artificial spawning hotspots”

We are developing techniques to restore coral populations by enhancing larval supply using “artificial spawning hotspots” that aggregate conspecific adult corals. However, no data were available regarding how natural larval supply from wild coral populations is influenced by fertilization rate and how this is in turn affected by local population density and genetic diversity. Therefore, we assessed population density and genetic diversity of a wild, arborescent coral, Acropora yongei, and compared these parameters with those of an artificially established A. yongei population in the field. The population density of wild arborescent corals was only 0.27% of that in the artificial population, even in a high‐coverage area. Genetic diversity was also low in the wild population compared with the artificial population, and approximately 10% of all wild colonies were clones. Based on these results, the larval supply in the artificial population was estimated to be at least 1,400 times higher than that in wild A. yongei populations for the same area of adult population.     

Finite element analysis of Stryker Xia pedicle screw in artificial bone samples with and without supplemental cement augmentation

A validated, using in vitro biomechanical testing, finite element model was used to evaluate the affects of (1) cement augmentation and (2) an intact posterior cortex in osteoporotic bone. The presence of augmentation and/or a posterior cortical cortex increased the stabilization of the pedicle screw 2–5 fold. Placement of cement influenced failure load and toggle; with distal placement having the largest increase in failure load and decrease in cephalad–caudad toggle. The presence of posterior cortex caused a decrease in the amount of toggle, a proximal shift of the center of rotation and an increase in the maximum failure force.     

Chemical limnology of two artificial lakes used for both stormwater management and recreation

The aims of this study were to document the mainly chemical behaviour of two linked artificial lakes used for both stormwater management and recreation in the new town of Craigavon. Further, the understanding of their behaviour should help in their management and the design of other similar lakes.The lake mean total phosphorus (73 µg P l^–1), nitrate (0.50 mg N l^–1) and chlorophyll a (25 µg l^–1) concentrations, Secchi depth (1.2 m) and the estimated total phosphorus loading (1.98 g m^–2 a^–1) all classify the main lake as eutrophic. An important source of the phosphorus load on the lakes is the urban area of Craigavon (52% of the total load). The interrelationships between total phosphorus, chlorophyll a and Secchi depth in the main lake are similar to those in natural ones. In addition, the lake follows the total phosphorus load — trophic state relationships (lake total phosphorus and chlorophyll a concentrations and Secchi depth) found to apply elsewhere. These two points indicate that the artificial lakes in Craigavon behave similarly to natural ones.     

Bacterial Artificial Chromosomes: A Functional Genomics Tool for the Study of Positive-strand RNA Viruses

Reverse genetics, an approach to rescue infectious virus entirely from a cloned cDNA, has revolutionized the field of positive-strand RNA viruses, whose genomes have the same polarity as cellular mRNA. The cDNA-based reverse genetics system is a seminal method that enables direct manipulation of the viral genomic RNA, thereby generating recombinant viruses for molecular and genetic studies of both viral RNA elements and gene products in viral replication and pathogenesis. It also provides a valuable platform that allows the development of genetically defined vaccines and viral vectors for the delivery of foreign genes. For many positive-strand RNA viruses such as Japanese encephalitis virus (JEV), however, the cloned cDNAs are unstable, posing a major obstacle to the construction and propagation of the functional cDNA. Here, the present report describes the strategic considerations in creating and amplifying a genetically stable full-length infectious JEV cDNA as a bacterial artificial chromosome (BAC) using the following general experimental procedures: viral RNA isolation, cDNA synthesis, cDNA subcloning and modification, assembly of a full-length cDNA, cDNA linearization, in vitro RNA synthesis, and virus recovery. This protocol provides a general methodology applicable to cloning full-length cDNA for a range of positive-strand RNA viruses, particularly those with a genome of >10 kb in length, into a BAC vector, from which infectious RNAs can be transcribed in vitro with a bacteriophage RNA polymerase.     

A Panicum-derived chromosomal segment captured by Hordeum a few million years ago preserves a set of stress-related genes

Intra-specific variability is a cornerstone of evolutionary success of species. Acquiring genetic material from distant sources is an important adaptive mechanism in bacteria, but it can also play a role in eukaryotes. In this paper, we investigate the nature and evolution of a chromosomal segment of panicoid (Poaceae, Panicoideae) origin occurring in the nuclear genomes of species of the barley genus Hordeum (Pooideae). The segment, spanning over 440 kb in the Asian Hordeum bogdanii and 219 kb in the South American Hordeum pubiflorum, resides on a pair of nucleolar organizer region (NOR)-bearing chromosomes. Conserved synteny and micro-collinearity of the segment in both species indicate a common origin of the segment, which was acquired before the split of the respective barley lineages 5–1.7 million years ago. A major part of the foreign DNA consists of several approximately 68 kb long repeated blocks containing five stress-related protein-coding genes and transposable elements (TEs). Whereas outside these repeats, the locus was invaded by multiple TEs from the host genome, the repeated blocks are rather intact and appear to be preserved. The protein-coding genes remained partly functional, as indicated by conserved reading frames, a low amount of non-synonymous mutations, and expression of mRNA. A screen across Hordeum species targeting the panicoid protein-coding genes revealed the presence of the genes in all species of the section Stenostachys. In summary, our study shows that grass genomes can contain large genomic segments obtained from distantly related species. These segments usually remain undetected, but they may play an important role in the evolution and adaptation of species.     

Artificial selection on allometry: change in elevation but not slope

To what extent within-species (static) allometries constitute a constraint on evolution is the subject of a long-standing debate in evolutionary biology. A prerequisite for the constraint hypothesis is that static allometries are hard to change. Several studies have attempted to test this hypothesis with artificial-selection experiments, but their results remain inconclusive due to various methodological issues. Here, we present results from an experiment in which we selected independently on the slope and the elevation of the allometric relationship between caudal-fin size and body size in male guppies (Poecilia reticulata). After three episodes of selection, the allometric elevation (i.e. intercept at constant slope) had diverged markedly between the lines selected to increase or decrease it, and showed a realized heritability of 50%. In contrast, the allometric slope remained unaffected by selection. These results suggest that the allometric elevation is more evolvable than the allometric slope, this latter representing a potential constraint on adaptive trait evolution. To our knowledge, this study is the first artificial-selection experiment that directly tests the evolvability of static allometric slopes.     

The society of selves

Human beings are not only the most sociable animals on Earth, but also the only animals that have to ponder the separateness that comes with having a conscious self. The philosophical problem of 'other minds' nags away at people's sense of who--and why--they are. But the privacy of consciousness has an evolutionary history--and maybe even an evolutionary function. While recognizing the importance to humans of mind-reading and psychic transparency, we should consider the consequences and possible benefits of being--ultimately--psychically opaque.