A numerical investigation of three-dimensional falling liquid films

Environmental Fluid Mechanics - In this article, we present a full three-dimensional numerical study of thin liquid films falling on a vertical surface, by solving the full three-dimensional...     

Incorporation of Seasonal Nitrogen Dynamics within a Long-Term Acidification Model

This paper describes an application of the long termdynamic model, MAGIC, on a monthly timestep, enablingincorporation of the seasonal dynamics associated with abroad understanding of the ecosystem N cycle. The modelhas been applied to the Dargall Lane catchment in theGalloway region of Scotland where marked seasonal Ndynamics are apparent. Mean monthly proportions ofrainfall, runoff, deposition fluxes and net retention ofN are utilised to drive the model on a monthly timestep.Calibration of the model has successfully reproduced thepresent day observed seasonal variation in streamNO₃ and ANC. Prediction of recovery at the siteunder the second sulphur protocol indicates that,although mean annual ANC increases, mean monthly ANC doesnot rise above zero for all months of the year until2010.     

环境样品中杀菌剂的多残留分析

苯并咪唑类化合物(benzimidazoles)如涕必灵(thiabendazole)常作为杀菌剂普遍用在瓜果及农作物上．用液相色谱法分析这些物质比较困难：例如涕必灵,在硅胶基质的色谱柱上会发生严重的拖尾现象,酸性条件下尤为明显。涕必灵和多菌灵(carbendazim)在pH10的情况下使用XTerra MS C18色谱柱会得到较好的峰形,但在较高的pH值下,其它类型杀菌剂或杀虫剂可能不稳定,故难以用适合这些碱性杀菌剂的高pH值条件进行同时分析．     

Environment as the Stage for Economic Actors

The relative importance of economics and environment in debate may soon be reversed due to the influence of three fac- tors. Firstly, in the global economy it is hard to hide the unwanted products of economic processes. Secondly, huge advances in sci- ence will reduce the imperfect knowledge of markets, making some monitoring and analyzing tools show the design of sensible and equitable livelihood in communities, which is more important than the motivation of maximising profits for some individuals or firms. Thirdly, China, as the last major player on the planet to take on economic growth, comes from traditions fundamentally differ- ent from those economies that have experienced the Industrial Revolution previously. Its challenges with sustainability and en- vironmental conservation predate Western economics by millennia, and it is implementing policies domestically and starting to work on the world stage that acknowledges that the surroundings are the host for any economic and socio-political system.     

Development of food preferences: social learning by Belding's ground squirrels Spermophilus beldingi

Summary The mechanisms by which food selection behavior develops may constrain the evolution of optimal foraging, yet these mechanisms have received relatively little attention in recent optimal foraging studies. We used cafeteria-style feeding trials to examine the role of social learning in the development of food preferences by a generalist mammalian herbivore, Spermophilus beldingi. Naive young spent relatively little time feeding and showed no preferences among five plant species offered in their feeding trials. This random pattern persisted for one set of young during two subsequent trials in the absence of their mother. A second group of young squirrels was tested initially alone, once with their mothers, and then once more alone. These squirrels fed more than those in the control group during their final trials, and showed significant preferences among plant species. These paralleled the preferences of their mothers. These results suggest that social learning may be important in the development of feeding behavior in ground squirrels, and provide a possible mechanism for cultural differences in food preferences among populations.     

Proposed guidelines for diagnosis of chromosome mosaicism in amniocytes based on data derived from chromosome mosaicism and pseudomosaicism studies

Currently, accepted protocol which has been developed at the Prenatal Diagnosis Laboratory of New York City (PDL) requires that when a chromosome abnormality is found in one or more cells in one flask, another 20–40 cells must be examined from one or two additional flasks. Chromosome mosaicism is diagnosed only when an identical abnormality is detected in cells from two or more flasks. In a recent PDL series of 12 000 cases studied according to this protocol, we diagnosed 801 cases (6.68 per cent) of single-cell pseudomosaicism (SCPM), 126 cases (1.05 per cent) of multiple-cell pseudomosaicism (MCPM), and 24 cases (0.2 per cent) of true mosaicism. Pseudomosaicism (PM) involving a structural abnormality was a frequent finding (2/3 of SCPM and 3/5 of MCPM), with an unbalanced structural abnormality in 55 per cent of SCPM and 24 per cent of MCPM. We also reviewed all true mosaic cases (a total of 50) diagnosed in the first 22000 PDL cases. Of these 50 cases, 23 were sex chromosome mosaics and 27 had autosomal mosaicism; 48 cases had numerical abnormalities and two had structural abnormalities. Twenty-five cases of mosaicism were diagnosed in the first 20 cells from two flasks, i.e., without additional work-up, whereas the other 25 cases required extensive work-up to establish a diagnosis (12 needed additional cell counts from the initial two culture flasks; 13 required harvesting a third flask for cell analysis). Our data plus review of other available data led us to conclude that rigorous efforts to diagnose true mosaicism have little impact in many instances, and therefore are not cost-effective. On the basis of all available data, a work-up for potential mosaicism involving a sex chromosome aneuploidy or structural abnormality should have less priority than a work-up for a common viable autosomal trisomy. We recommend revised guidelines for dealing with (1) a numerical versus a structural abnormality and (2) an autosomal versus a sex chromosome numerical aneuploidy. Emphasis should be placed on autosomes known to be associated with phenotypic abnormalities. These new guidelines, which cover both flask and in situ methods, should result in more effective prenatal cytogenetic diagnosis and reduced patient anxiety.     

Application of anaerobic and aerobic activated sludge to phosphorus-deficient wastewater treatment.

Anaerobic and aerobic (AnA) and completely aerobic (CA) sequencing-batch reactors (SBRs) were used to investigate the suitability of the AnA process for treating phosphorus (P)-deficient wastewaters with highly variable influent chemical oxygen demand (COD) loading. Both SBRs were subjected to influent COD loading patterns (LPs) that simulated (1) daily COD loading fluctuations, (2) weekend shutdowns, and (3) long weekend or holiday shutdowns. During LP 1, the AnA SBR produced lower average effluent soluble phosphorus concentrations than CA SBR (0.4 vs. 1.0 mgP/L). A similar result was observed during LP 2, but effluent acetate was detected after the first high COD loading cycle of the weekday loading period. During LP 3, the volatile suspended solids content of both reactors dropped sharply, and the effluent quality of both SBRs deteriorated. Model predictions suggest that the AnA process is stable when treating LP 1, but eventually fails when treating LP 2.     

Patterns and ecological predictors of age-related performance in female North American barn swallows,Hirundo rustica erythrogaster

Life history theory describes the optimization of important trade-offs within an individual’s lifetime and predicts that an individual’s reproductive performance (RP) will improve up until a point of senescence. Despite abundant evidence for this pattern, relatively few studies consider the mechanisms associated with age-related improvements in RP. In this study, we aimed to describe patterns of age-related RP (seasonal fledgling production) in female North American barn swallows (Hirundo rustica erythrogaster) using a longitudinal data set to test multiple hypotheses about the social, morphological, and ecological factors underlying this prominent life history pattern. To address these objectives, we used generalized linear mixed models in a three-step series of analyses in which we assessed (1) patterns of female age-related RP; (2) the influence of age on changes in social, morphological, and ecological factors; and (3) whether the changes in RP were concomitant with changes in these factors. We found that (1) females showed patterns of age-related reproduction, in which performance increased in the first 2 years of breeding and decreased thereafter, (2) female tail streamer length increased and the extent of breast coloration increased then decreased significantly with age, and (3) changes in morphological traits did not covary with changes in reproductive performance over time. Our within-individual results highlight the importance of considering explicit links between morphology and reproductive performance that are not easily captured by population-level analyses.