Spreadsheets for water management — a case study from the Brantas Delta,East Java     

N. Bullock  M. A. Burton 《Irrigation and Drainage Systems》1988,2(3):259-278

The use of commercially available spreadsheet programs for scheduling of water supplies for large scale irrigation networks is a relatively new phenomenom. The paper describes the development and application of such a program for a 30 000 ha irrigation scheme in the Brantas Delta, East Java. The program has been in use for day-to-day scheduling of main system supplies since April 1986, during which time refinements and adjustments have been necessary to formulate a working package. The paper draws conclusions regarding the value of the program for improving water management.  相似文献   

Evolution of a paleo-argillic brown earth (paleudalf) from oxfordshire,England     

P. Bullock  C.P. Murphy 《Geoderma》1979,22(3):225-252

The complex developmental history of a paleo-argillic brown earth in Plateau Drift has been investigated using mainly micromorphological techniques. Eight kinds of pedological features are identified, quantified and related to a probable sequence of soil-forming events. Three “stable” periods of soil formation are recognised, one pre-dating emplacement of the Plateau Drift and the other two associated respectively with one or more interglacial periods between deposition of the drift and the onset of the last glaciation (Devensian) and the post-Devensian period. Clay illuviation and reduction and segregation of iron oxides are the main processes recognised in all three periods and reddening is associated with the periods before the last glaciation. Although the soil was probably subjected to several “unstable” periods only two are distinguished. The first is associated with erosion, disruption and mixing of soils and sediments, followed by transport and emplacement of the Plateau Drift. The second is related to the Devensian glaciation and is characterised by erosion, cryoturbation and deposition of loess on the eroded surface.  相似文献   

Traditional soil and land appraisal on fadama lands in northeast Nigeria   总被引：2，自引：0，他引：2  

A. M. Kundiri  M. G. Jarvis  P. Bullock 《Soil Use and Management》1997,13(4):205-208

Abstract. As part of a study of recession farming on the 'fadama' lands on a segment of the Komadugu-Yobe floodplain, a survey was carried out to investigate the local farmers' perception of soil types and management practices. The farmers are clearly aware of the differences in soil type on the fadama and they possess unique skills in managing their farm lands. The farmers classify fadama soils for recession farming by assessing soil texture and soil drainage conditions by feel and observation. Integrating such local knowledge into soil surveys will lead to better practical definition of mapping units and give soil names that have more meaning for the farmers.  相似文献   

Identification of commercial sources     

Bullock DW 《Science (New York, N.Y.)》1973,182(4112):535-536

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Unwinding of duplex DNA from the SV40 origin of replication by T antigen   总被引：49，自引：0，他引：49  

M Dodson  F B Dean  P Bullock  H Echols  J Hurwitz 《Science (New York, N.Y.)》1987,238(4829):964-967

The T antigen specified by SV40 virus is the only viral-encoded protein required for replication of SV40 DNA. T antigen has two activities that appear to be essential for viral DNA replication: specific binding to duplex DNA at the origin of replication and helicase activity that unwinds the two DNA strands. As judged by electron microscopy, DNA unwinding is initiated at the origin of replication and proceeds bidirectionally. Either linear or circular DNA molecules containing the origin of replication are effective substrates; with closed circular DNA, a topoisomerase capable of removing positive superhelical turns is required for an efficient reaction. Presence of an origin sequence on duplex DNA and a single-strand DNA-binding protein appear to be the only requirements for T antigen to catalyze unwinding. This reaction mediated by T antigen defines a likely pathway to precise initiation of DNA replication: (i) the sequence-specific binding activity locates the origin sequence, (ii) the duplex DNA is unwound at this site, and (iii) the DNA polymerase and primase begin DNA replication. A similar pathway has been inferred for the localized initiation of DNA replication by bacteriophage lambda and by Escherichia coli in which a sequence-specific binding protein locates the origin and directs the DnaB helicase to this site. Observations with the SV40 system indicate that localized initiation of duplex DNA replication may be similar for prokaryotes and eukaryotes.  相似文献   

IS MALIGNANCY DUE TO A PROCESS ANALOGOUS TO SOMATIC MUTATION?     

Curtis MR  Dunning WF  Bullock FD 《Science (New York, N.Y.)》1933,77(1989):175-176

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A synthetic nickel electrocatalyst with a turnover frequency above 100,000 s⁻¹ for H₂ production     

Helm ML  Stewart MP  Bullock RM  DuBois MR  DuBois DL 《Science (New York, N.Y.)》2011,333(6044):863-866

Reduction of acids to molecular hydrogen as a means of storing energy is catalyzed by platinum, but its low abundance and high cost are problematic. Precisely controlled delivery of protons is critical in hydrogenase enzymes in nature that catalyze hydrogen (H(2)) production using earth-abundant metals (iron and nickel). Here, we report that a synthetic nickel complex, [Ni(P(Ph)(2)N(Ph))(2)](BF(4))(2), (P(Ph)(2)N(Ph) = 1,3,6-triphenyl-1-aza-3,6-diphosphacycloheptane), catalyzes the production of H(2) using protonated dimethylformamide as the proton source, with turnover frequencies of 33,000 per second (s(-1)) in dry acetonitrile and 106,000 s(-1) in the presence of 1.2 M of water, at a potential of -1.13 volt (versus the ferrocenium/ferrocene couple). The mechanistic implications of these remarkably fast catalysts point to a key role of pendant amines that function as proton relays.  相似文献   

Towards a World Soil Survey Archive and Catalogue     

S. H. Hallett    P. Bullock  & I. Baillie 《Soil Use and Management》2006,22(2):227-228

An extensive collection of soil, land resource and land suitability surveys undertaken worldwide over the last 80 years by soil surveyors and scientists at the behest of the British government and others has been archived and catalogued using internationally recognized bibliographic standards. The World Soil Survey Archive and Catalogue (WOSSAC) consisting of over 13 000 reports and maps is now available for consultation and use by the international soil science community.  相似文献   

Protein bound iodine determination as a diagnostic aid for canine hypothyroidism     

L Bullock 《Journal of the American Veterinary Medical Association》1970,156(7):892-899

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Protein and energy restriction for replacement pullets     

D. W. Bullock  T. R. Morris  S. Fox 《British poultry science》1963,4(3):227-237

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