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  • Blackwell Publishing Ltd  (149)
  • Oxford University Press  (57)
  • 1995-1999  (132)
  • 1985-1989  (74)
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of the American Water Resources Association 31 (1995), S. 0 
    ISSN: 1752-1688
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Geography
    Notes: : This paper describes a procedure to design pluvial drainage systems in such a way as to prevent large excavation volumes and erosive velocities. To this end the storage capacity of the channel system is taken into account. In a preliminary step, the procedure employs an approximate method to determine the channel dimensions. Therefore, the dimensions are adjusted by means of a numerical method of solution of the unsteady flow equations. An example is included.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 32 (1985), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Sodium dodecyl sulfate (SDS) and 2-mercaptoethanol (2-ME) activated proteolytic enzymes present in extracts of Entamoeba histolytica and E. invadens; SDS (0.5%) and 2-ME (1.4 and 715 mM) doubled the enzymatic activity when assayed on a stained insoluble substrate. Urea (4 M) did not reduce this activity, suggesting that amebic proteases are stable in the above denaturant conditions. Specific reagents for sulfhydryl (-SH) groups completely inhibited proteolytic activity regardless of pH. Inhibition with alkylating agents, such as N-ethylmaleimide and iodoacetamide, was reversed with 715 mM 2-ME as was also observed with papain. We conclude from these results that the main proteolytic enzymes contained in extracts of E. histolytica and E. invadens are dependent on free thiol groups.
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 42 (1995), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Phytomonas sp. membranes have an adenylyl cyclase activity which is greater in the presence of Mn2+ than with Mg2+. The Mg2+ and Mn2+ activity ratio varies from one membrane preparation to another, suggesting that the adenylyl cyclase has a variable activation state. A [35S]GTP-γ-S-binding activity with a Kd of 171 nM was detected in Phytomonas membranes. Incubation of these membranes with activated cholera or pertussis toxin and [adenylate 32P]NAD+ led to incorporation of radioactivity into bands of about 40–44 kDa. Crude membranes were electrophoresed on SDS-polyacrylamide gels and analyzed, by Western blotting, with the 9188 anti-αs antibody and the AS/7 antibody (anti-α1, anti-αi1, anti-αi2). These procedures resulted in the identification of polypeptides of approximately 40–44 kDa. Phytomonas adenylyl cyclase could be activated by treatment of membrane preparations with cholera toxin, in the presence of NAD+, while similar treatment with pertussis toxin did not affect this enzyme activity. These studies indicate that in Phytomonas, adenylyl cyclase activity is coupled to an unknown receptor entity through Gαs, proteins.
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  • 4
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . We describe the in vitro culture of Phytomonas species isolated from Euphorbia characias. The best choice between tested media was SDM-79, in which promastigotes, after 6 days of culture, reached cell densities as high as 4 × 107 cells/ml. Cells growing in LIT or MTL medium showed longer division times and lower cell densities. We succeeded in obtaining Phytomonas sp. amastigote and spheromastigote forms in modified GRACE's medium, yielding transformation rates of up to 70%. Electron microscopy studies were performed in order to characterize the ultrastructural features of these forms obtained in vitro. On the other hand, metabolic studies based on qualitative (nuclear magnetic resonance spectroscopy) and quantitative metabolic methods (enzymatic assays) showed that promastigote forms secreted mainly ethanol, acetate, glycine, glycerol, piruvate and succinate in SDM-79 medium, whereas the major metabolites found after transformation in modified Grace's medium were ethanol, acetate, glycine, piruvate and smaller amounts of glycerol.
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 33 (1986), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . Restriction endonuclease mapping of the Trypanosoma cruzi kinetoplast DNA maxicircle was performed in nine cloned stocks using maxicircle probes from T. brucei. Analysis of the maxicircle 13–15-kbp encoding region allowed cloned stocks to be divided into three groups: A, B, and C. Parasites from groups A and B had 3% sequence divergence while parasites from group C showed 16–17% sequence divergence with regard to parasites from groups A and B. Cross-hybridization experiments demonstrated that the 23–25-kbp maxicircle divergent region was similar in sequence in group A and B, but different in group C parasites. The high homology of the T. cruzi and T. brucei encoding regions allowed the use of T. brucei probes to detect T. cruzi transcripts, whose overall picture did not differ for parasites from any of the nine assayed clones.
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    The @journal of eukaryotic microbiology 44 (1997), S. 0 
    ISSN: 1550-7408
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: . The energy metabolism was compared among four different representatives of the genus Phytomonas isolated from different plants and localities: the sieve tubes of the hartrot-infected coconut palm in French Guyana, the latex fluid of Euphorbia hyssopifolia in French Guyana and the fruits of tomato and cherimoya in Spain. All four isolates produced acetate, ethanol, glycerol and glycine as metabolic end-products. In addition, small amount of succinate and pyruvate were excreted. Only minor quantitative differences were observed in the four isolates. Glycosomes, harboring the glycolytic enzymes, were present in all isolates. No evidence was found for an active involvement of the mitochondrion in metabolism. Respiration was insensitive to the classical inhibitors of the respiratory chain, such as antimycin and potassium cyanide, but inhibited by salicylhydroxamic acid. No evidence was found for the functioning of a citric-acid cycle. It is concluded that representative of this genus share the same highly active carbohydrate metabolism combined with a complete suppression of mitochondrial activity.
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  • 7
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Geophysical prospecting 34 (1986), S. 0 
    ISSN: 1365-2478
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geosciences , Physics
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    R & D management 19 (1989), S. 0 
    ISSN: 1467-9310
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: The author has investigated the role played by project selection methods in defining a firm's technology strategy, as exemplified by a sample of innovative companies in Spain. The information was collected by a combination of questionnaire and interview with key personnel.The author was able to classify strategies into four groups: (1) a planning strategy, essentially a negotiation comprising top-down and bottom-up elements; (2) an economic strategy in which a large number of economic criteria set in advance by top management are used to evaluate projects; (3) a market strategy in which R&D is seen more or less as an adjunct to the Marketing function, which defines the products needed and negotiates the programme with top management; (4) a technical strategy, used in circumstances in which technological innovation is essential and in which, therefore, economic factors take a subsidiary place.The author's data show that in companies operating a planning strategy project selection methods of various, perhaps ad hoc kinds play a key role in reaching a company consensus. For those using an economic strategy the selection criteria are predetermined and selection methods inflexible. In the case of the market strategy, evaluation methods are used solely to help to rank projects prior to selection. Firms employing the technical strategy clearly base their decisions purely on the technical merit of the various projects put up for implementation.The paper includes information on the types of selection method used, broken down by company size and other similar criteria, and comparisons with practice in the USA, France and some other countries.
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Labour 9 (1995), S. 0 
    ISSN: 1467-9914
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Economics
    Notes: Abstract. This paper presents evidence that firm-level productivity increases when the relative wage rises, or the level of unemployment rises. Both facts are consistent with the efficiency wage model. Moreover, there is support for the idea that an increase in the sector's wage with respect to the previous year also increases productivity. We obtain the empirical evidence through a double-hurdle model. We use this estimation technique because it can be established that the differences in productivity between sectors could be explained by differences in effort. It means that some of the industrial sectors of the Spanish economy may pay wage premia while others do not. We also test this implication through panel data.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Ground water 37 (1999), S. 0 
    ISSN: 1745-6584
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Geosciences
    Notes: Specific capacity (Q/s) data are usually much more abundant than transmissivity (T) data. Theories which assume uniform transmissivity predict a nearly linear relationship between T and Q/s. However, linear dependence is seldom observed in field studies. Since hydrogeologic studies usually require T data, many hydrogeologists use linear regression analysis of T versus Q/s data to estimate T values where only Q/s data are available. In this paper we use numerical models to investigate the effects of aquifer heterogeneity on the relationship between Q/s and T estimates. The simulations of hydraulic tests in heterogeneous media show that estimates of T derived using Jacob's method tend to their late-time effective value much faster than Q/s values. The latter are found to be more dependent upon local transmissivities near the well. This explains why the regression parameters for T versus Q/s data depend on heterogeneity and the‘lateness’of the test period analyzed. Since this effect is more marked in high T zones than in low T zones, we conclude that natural aquifer heterogeneity can explain the convex deviation from linearity often observed in the field. A further result is that the geometric mean of T estimates, obtained from short and intermediate time pumping tests, seems to systematically underestimate effective T (Teff) of heterogeneous aquifers. In the studied simulation cases, the median of the T values or the arithmetic mean yield better estimates for Teff.
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