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1.
The history of eutrophication of the Loosdrecht Lakes system and the differences in trophic state of the compartments of this system are described from a hydrological point of view. Groundwater movement was found to be of paramount importance. This groundwater transport induced a horizontal surface water transport with concomitant biomass from Loosdrecht Lakes to Lake Breukeleveen, which explains partly the more eutrophic situation in the latter lake. The article summarizes several internal WOL-reports (ENGELEN and KAL, 1985; HETTLING, 1985a, b; KUHNEL, 1985; TEUNISSEN, 1985).  相似文献   

2.
During the course of determining the sequence of a large DNAfragment, it is necessary to cross-check numerous gel readingsfrom different DNA fragments, in order to track and eliminatemistakes. An algorithm is presented that takes advantage ofthe high degree of homology between such sequences to constructan alignment of the matching regions. It does not require knowledgeof a starting homology zone, neither large memory areas, evenfor sequences of several kilobases, and it can overcome largegaps or mismatch zones that correspond for instance to misinterpretationof compressions on sequence gels. This algorithm has been implementedin 6502 assembly language on an Apple II computer as an extensionto the PEGASE sequence handling system. Received on May 21, 1985; accepted on July 19, 1985  相似文献   

3.
The simple control system of cellular automata makes them verygood analogues for biological mechanisms, in particular someof the colour patterns found on the shells of certain molluscs.There is scope for both experimental and observational workto test the usefulness of such an analogue. (Received 14 July 1985;  相似文献   

4.
经济快速增长区城市用地空间扩展对生态安全的影响   总被引:5,自引:0,他引:5  
张健  高中贵  濮励杰  彭补拙 《生态学报》2008,28(6):2799-2799~2810
目前我国正处于经济快速发展、城市化进程加快阶段,承受着生态环境恶化的巨大压力,大多数城市已为环境污染、空间拥挤、绿化率低、秩序混乱等严重的城市问题所困扰.昆山市作为我国经济发展最为活跃的地区之一,其城市化过程与生态环境安全之间的矛盾更为突出.在总结国内外生态安全和城市生态研究的基础上,分析城市用地扩展对城市生态安全产生的影响.昆山市城市用地空间扩张经历了缓慢发展期(1949~1977年)、老城区改造期(1977~1985年)、新区开发期(1985~1999年)和快速扩展期(1999年至今)4个阶段,针对城市土地利用变化特征及其城市土地利用存在的问题,对昆山市城市用地空间扩展进程和模式及扩展的主要特征方面进行剖析.从城市废水、废气和固废排放量几个方面分析了昆山城市用地空间扩展过程中生态环境变化情况,指出高速工业化、城市化过程,快速增长的经济可能威胁到昆山城市的生态安全.同时建立城市生态安全评价模式,构建城市生态安全评价的指标体系,探讨城市生态安全评价的方法,评价了昆山市1985~2004年的城市生态安全,最后对昆山市未来城市生态安全进行预警.为维护昆山市的生态安全,实现可持续发展提供科学依据.  相似文献   

5.
An algorithm and a program have been developed which enableoptimal alignments of biological sequences on an 8–bitmicrocomputer. The compiled program can process sequences upto 1000 residues on a Commodore 64. Since this program was writtenoriginally in the BASIC language, it may readily be adaptedto other microcomputers with small changes. Received on March 11, 1985; accepted on March 14, 1985  相似文献   

6.
B arak , M., M erzbach D. & U litzur , S. 1985. A note on the increased permeability of opsonized luminous bacteria. Journal of Applied Bacteriology 59 , 57–59.
Opsonization of a dark variant of the luminous bacterium Photobacterium leiog-nathi by pooled human serum caused an increase in the permeability of the organism to actinomycin D, as judged by the inhibition of the proflavin-induced synthesis of its luminescence system.  相似文献   

7.
Simulation model for niche shift in ecological time scale was constructed on the basis of the optimal foraging theory. In accordance with the previous experimental study (Shimada andFujii , 1985), the model competitive system consisted of 2 parasitoid wasp species utilizing 4 host stages. Wasps were assumed to choose host stages in the manner that they realized the maximal gain/cost values, where gain was represented by body weight of a wasp progeny emerging from each host stage and cost was expressed by time required to search for and detect an unparasitized host. The number of parasitized hosts in each host stage was calculated numerically by usingArditt 's (1983) model for avoidance of superparasitism. The model simulated well the experimental results ofShimada andFujii (1985) andShimada (1985). Sensitivity analysis of the model showed that the experimentally derived criterion for competitive coexistence (different second-best host stages between competing species even with the common best) was not necessarily the indispensable condition for niche shift and separation, but that if the criterion was not satisfied, stable competitive coexistence occurred only in the narrow range of the parametric values. Further, niche shift in ecological time scale made the competitive coexistence more stable than fixed niche on which the current niche theory stands.  相似文献   

8.
9.
Total ribosomes (monosomes plus polysomes) isolated from woundedpea epicotyls are more efficient at supporting protein synthesisin a wheat germ S30 system (containing wheat ribosomes) thanare total ribosomes from aged (control) pea tissue. This increasedefficiency is seen when enriched large polysomes, almost devoidof monosomes, are used to program a wheat germ S300 system,from which the wheat germ ribosomes have been removed. Reactionsprimed by enriched polysomes from wounded tissue, but not agedtissue, continue for at least 30 min, suggesting that reinitiationis occurring during the reaction, albeit in the initial absenceof monosomes from wheat or pea. Wheat germ ribosomes, but notmonosomes from either aged or wounded pea tissue, are able totranslate pea poly(A) RNA and globin mRNA. Aurintricarboxylicacid reduces protein synthesis in a rather indiscriminate manner,whereas, pactamycin seems to have an inhibitory effect specificfor initiation, and it is much more effective on wounded thanon control tissue polysomes. We interpret these results to implythat polysomal ribosomes from wounded tissue are more efficientat initiation than are polysomal ribosomes from control tissueor than non-polysomal ribosomes (monosomes) from either tissue. (Received May 7, 1985; Accepted July 4, 1985)  相似文献   

10.
H olland , K.T. & D avis , W. 1985. A note on an in vitro test system to compare the bactericidal properties of wound dressing. Journal of Applied Bacteriology 59 , 61–63.
An in vitro method of comparing the antimicrobial properties of dressings used on human skin is described and has been tested with two samples of tulle gras. The method has advantages over agar diffusion methods by providing flexibility of test conditions and kinetic data for analysis.  相似文献   

11.
A key to the classes, orders, families, and subfamilies of Acanthocephala based on the Meyer-Van Cleave system as presented by Amin (1985) is provided. A new class (Polyacanthocephala) and a new order (Polyacanthorhynchida) are erected to accommodate members of the monogeneric family Polyacanthorhynchidae Golvan, 1956.  相似文献   

12.
OBJECTIVE--To assess changes in the organisation and performance of cervical cytology programmes in the practices of members of the Vale of Trent faculty of the Royal College of General Practitioners. DESIGN--Retrospective audits completed in 1985 and 1988 by general practitioners on a sequential sample of 100 records of women aged 35-64 in their practice. SETTING--General practices in which one or more partners were members or associates of the Vale of Trent faculty of the college, of which 76 participated in the first audit and 55 (82% of 67 eligible practices) in the second. SUBJECTS--Sequential samples of 100 women born between 1 January 1920 and 31 December 1949 (first audit) and between 1 January 1923 and 31 December 1952 (second audit) whose surnames began with P or B respectively. MAIN OUTCOME MEASURES--Percentage of women in each practice with a record of cervical cytology performed in the previous five years and percentage with no recorded smear. RESULTS--Of the 76 practices completing the audit in 1985, 55 (82% of those eligible) repeated the exercise in 1988. Performance was not significantly different in practices that did and did not respond. The median percentage of women who had had a smear in the previous five years was 49% and 69% in 1985 and 1988 respectively (p less than 0.001) and that of women with no record of a cervical smear was 28% and 16% respectively (p less than 0.001). All but six practices showed improvement in both outcome measures. In both audits an active call system was associated with a significantly increased performance (p less than 0.05). In nine practices (16%) 80% or more of the samples of women had had a smear in the previous five years. CONCLUSION--Organisation and performance of practices audited improved between 1985 and 1988. Although this might result from participation in the first audit, it probably represents a more general trend within primary care. ACTION--Between the two audits more practices (87% v 67%) had developed a policy on screening, and this was more likely to include the aim of performing regular smears on all sexually active women (98% v 80%).  相似文献   

13.
Secular changes of head measurements (frontal breadth, bizygomatic breadth, bigonial breadth, auricular height, morphological facial height, lower face height) are analysed. The data are based on the Jena anthropological investigations of school children from 1975 and 1985. The inclusion of the data of the Jena longitudinal study carried out since 1985 allows an analysis of the further secular trend. Noticeable changes are proved in most of the analysed traits (frontal breadth, bigonial breadth, auricular height, morphological facial height, lower face height) between 1975 and 1985. The vertical measurements show greater percentage differences than the horizontal measurements, which, among other things, results in a relative narrowing of the face. In some head measurements (frontal breadth, bigonial breadth, auricular height) the trends continue after 1985. The secular trends show no obvious connection with the temporal acceleration of the dentition in the probands of the longitudinal study. However, a connection seems to be possible between the accelerated puberal growth spurt of the body height and the puberal growth spurt in some head dimensions.  相似文献   

14.
We present an algorithm for prediction of RNA secondary structures.The program consists of three parts: the first computes locationand free energy of every possible stem–loop structure,the second computes probability of its formation, and the thirdlists the positions and free energies of all the stem–loopsin the order of their probability sizes. The circular RNA moleculeof chrysanthemum stunt viroid was used as an input data fordemonstrating the operation of the program. Received on March 14, 1985; accepted on March 18, 1985  相似文献   

15.
Software for non–linear curve fitting has been writtenin BASIC to execute on the British Broadcasting CorporationMicrocomputer. The program uses the direct search algorithmPattern–search, a robust algorithm that has the additionaladvantage of needing specification of the Junction without inclusionof the partial derivatives. Although less efficient than gradientmethods, the program can be readily configured to solve low–dimensionaloptimization problems that are normally encountered in lifesciences. In writing the software, emphasis has been placedupon the ‘user interface’ and making the most efficientuse of the facilities provided by the minimal configurationof this system. Received on March 4, 1985; accepted on March 14, 1985  相似文献   

16.
Combined analysis of 5,179 serial phage reactions of 20 Listeria monocytogenes propagating strains over 14 years and phage typing results from 2,659 further L. monocytogenes strains allowed us to estimate lytic spectrum specificity and the variability of the lytic reactions of 35 phages. These included the 26 phages recommended for the international method for phage typing defined in 1985 by Rocourt et al. (J. Rocourt, A. Audurier, A. L. Courtieu, J. Durst, S. Ortel, A. Schrettenbrunner, and A. G. Taylor, Zentralbl. Bakteriol. Abt. 1 Orig. A 259:489-497, 1985). The results are discussed individually for each phage. Proposals for modifying the present system are made with the aim of producing an optimal bacteriophage set for routine use.  相似文献   

17.
EBV episomes are nuclear plasmids that are stably maintained through multiple cell divisions in primate and canine cells (J. L. Yates, N. Warren, and B. Sugden, Nature 313:812-815, 1985). In this report, we describe the construction and characterization of an E1-deleted recombinant adenovirus vector system that delivers an EBV episome to infected cells. This adenovirus-EBV hybrid vector system utilizes Cre-mediated, site-specific recombination to excise an EBV episome from a target recombinant adenovirus genome. We demonstrate that this vector system efficiently delivers the EBV episome and stably transforms a large fraction of infected canine D-17 cells. Using a colony-forming assay, we demonstrate stable transformation of 37% of cells that survive the infection. However, maximal transformation efficiency is achieved at doses of the E1-deleted recombinant adenoviruses that are toxic to the infected cells. Consequently, E1-deleted vector toxicity imposes a limitation on our current vector system.  相似文献   

18.
方宗杰 《古生物学报》2007,46(4):481-485
对Yangtzedonta pri mitivaYu模式标本(标本登记号:84430)的化石保存类型进行讨论,确认这应当是一枚单壳瓣实体标本,而非内模标本,由此判断,余汶(1985;Yu,2005)所描述的肌痕实际上是不存在的。所谓的"片状齿突"(余汶,1985)或"片状脊"(Yu,2005)很可能是外来的附加物,并非壳体的组成部分。无论如何,84430标本现有的形态证据尚不足于将它与双壳类联系在一起。  相似文献   

19.
OBJECTIVES--To evaluate a public campaign to encourage earlier referral and treatment of primary cutaneous malignant melanoma and thus reduce mortality related to melanoma. DESIGN--Production and distribution of educational material aimed at adults. Update information sent to general practitioners before campaign. Analysis of data on melanoma before and after campaign in June 1985. SETTING--West of Scotland, population 2.7 million. MAIN OUTCOME MEASURES--Total numbers of referrals per month to melanoma clinic, numbers of melanomas diagnosed, change in distribution of thickness, and mortality before and after introducing the campaign. RESULTS--Referrals to the pigmented lesion clinic increased by 278%, from five a week in June-July 1984 to 19 a week in June-July 1985. Twice as many women as men were referred to the clinic (49% of referrals were of women aged under 65). The numbers of newly diagnosed primary cutaneous melanoma were 63 (12/month) in January-May 1985 and 146 (21/month) in June-December 1985, an increase of 131%. The percentage of tumours detected that were less than 1.5 mm thick rose significantly by 16% (95% confidence interval 11% to 19%), from 38% (328) in 1979-84 to 54% (592) in 1985-9. Mortality began to fall in women from 1988. CONCLUSIONS--The public education campaign succeeded in reducing the absolute number of thick tumours and melanoma related mortality in women.  相似文献   

20.
Summary Treatment of 1-day-old worker honey bees with the juvenile hormone analog methoprene prematurely reduced their behavioral threshold sensitivity to alarm pheromones. Electroantennogram assays indicated that peripheral perception was not affected; the effects apparently occurred in the central nervous system. These results support a model (Robinson 1987) of division of labor based on the hormonal regulation of response thresholds to task-associated stimuli. Coupled with other studies (Breed 1983; Robinson 1985), they also suggest that: 1) aggression in the honey bee is hormonally mediated and 2) a single hormone is involved in both the production and perception of an olfactory communication signal, the first report of this phenomenon in an invertebrate.Abbreviations JH juvenile hormone - CNS central nervous system - EAG electroantennogram  相似文献   

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