Skip to main content

David Norman

University of Cambridge, Department of Earth Sciences, Faculty Member

Followers

78

Following

14

Co-authors

9

Mentions

1

Public Views

A palaeobiologist with interests in the evolution of life on dynamic Earth, with particular reference to vertebrate fossil animals of the Mesozoic Era. Work at the intersection between anatomy, functional biology, engineering design, physiology, ecology, systematics phylogenetics and palaeobiogeography.

less

InterestsView All (6)

Uploads

Papers by David Norman

A new hypothesis of dinosaur relationships and early dinosaur evolution

Nature, Mar 22, 2017

For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. ... more For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early...

Re-description of the postcranial skeleton of the middle Jurassic stegosaurHuayangosaurus taibaii

Journal of Vertebrate Paleontology, 2006

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, a... more JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact

The phylogeny of the ornithischian dinosaurs

Journal of Systematic Palaeontology, 2008

SÁNCHEZ-VILLAGRA, M. R. & CLACK, J. A. (eds) 2004. Fossils of the Miocene Castillo Formation, Venezuela: Contributions in Neotropical Palaeontology. Special Papers in Palaeontology no. 71. 112 pp. London: The Palaeontological Association. Price £48.00 (paperback). ISBN 0 901702 82 X

Geological Magazine, 2005

Cranial design and function in a large theropod dinosaur

Nature, 2001

This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. Endnote Workbo... more This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. Endnote Workbook with exercises EndNote is software which enables you to: • Maintain a database (called a Library) of references • Import references from other databases • Embed references from the database into a word processed document • Produce bibliographies in an appropriate style for submission or publication.

ChemInform Abstract: ChemInform Abstract: Synthesis and Antifungal Properties of Benzylamines Containing Boronate Esters

Cheminform, 2002

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Status of Agricultural Economics in Selected Countries in Eastern and Southern Africa

Determinants of Kansas Farmers' Participation in On-Farm Research

Journal of Agricultural and Applied Economics, 1997

On-farm research (OFR) has increased in popularity in the U.S. in recent years due to heightened ... more On-farm research (OFR) has increased in popularity in the U.S. in recent years due to heightened interest in sustainability issues, the likely decline in resources available for agricultural research, and increasing pressures for accountability and responsiveness to state and local needs. Information relating to OFR was obtained from 431 commercial Kansas farmers. Data were analyzed to determine the degree of OFR being implemented, and three models were estimated to identify which farrner/farrn characteristics influenced its implementation, The results indicate that OFR is commonly implemented, and that several farm/farmer characteristics are related to the degree of OFR initiated. It is proposed that to maximize the return from externally initiated OFR, there would be merit in focusing attention on farms/farmers with those characteristics.

Resistance Levels of Pot Anthurium Cultivars to Xanthomonas campestris pv. dieffenbachiae

Hortscience, Jul 1, 1999

Additional index words. disease resistance, ornamental plant breeding Abstract. One cut-flower an... more Additional index words. disease resistance, ornamental plant breeding Abstract. One cut-flower and 14 pot anthurium cultivars were screened for resistance to anthurium blight by spraying four isolates of Xanthomonas campestris pv. dieffenbachiae (McCulloch and Pirone) Dye onto leaf surfaces in replicated experiments. Varying degrees of resistance were observed among the 15 cultivars tested. The pot cultivars Julia and Gemini were the most resistant, while the cut-flower cultivar Hearts Desire was the most susceptible. Each cultivar displayed different degrees of resistance to individual isolates of the pathogen. The results of this research permit the selection of clones with greater resistance for use in breeding and also create a baseline for comparing resistance of newly developed cultivars.

Satellite laser ranging using pseudonoise code modulated laser diodes

Applied Optics, Sep 1, 1988

Techniques for satellite laser ranging have historically employed high-energy pulsed lasers as th... more Techniques for satellite laser ranging have historically employed high-energy pulsed lasers as the optical transmitter. The output power currently available from laser diodes and laser diode arrays makes them a viable alternative to the pulsed laser for ranging applications. The modulation of a laser diode is examined by a pseudonoise code which produces a CW ranging signal with equivalent average power to that of current pulsed systems. A maximum-likelihood receiver for estimating signal arrival time using ideal rectangular pulses is shown to be a correlation receiver. A Cramer-Rao bound on the range error is derived for a ranging system with Gaussian code pulses and a correlation receiver. Ranging performance is evaluated for a single cube-corner retroreflector and a tilted flat diffuse target. It is shown that range accuracy of the order of 1 cm is feasible.

Classification and Identification of Xanthomonas translucens Isolates, Including Those Pathogenic to Ornamental Asparagus

Phytopathology, Aug 1, 2006

Rademaker, J. L. W., Norman, D. J., Forster, R. L., Louws, F. J., Schultz, M. H., and de Bruijn, ... more

Resistance in Twenty-two Cultivars of Spathiphyllum to Cylindrocladium Root Rot

Horttechnology, 1999

SUMMARY. Twenty-two spathiphyllum cultivars were evaluated for resistance to Cylindrocladium root... more SUMMARY. Twenty-two spathiphyllum cultivars were evaluated for resistance to Cylindrocladium root rot (CRR). Four isolates of the fungus Cylindrocladium spathiphylli Shoult., El-Gholl & Alf. were selected from two different locations each in Florida and Hawaii. Spores of isolates were applied as a soil drench in replicated experiments using a randomized complete block design. The most severe symptoms were those produced by C. spathiphylli isolates from Hawaii. None of the spathiphyllum cultivars tested were highly resistant to CRR although resistance among the cultivars was observed. The cultivars Chris and Textura were the most promising cultivars, having fairly uniform resistance to the four isolates of C. spathiphylli. The cultivars Cupido, Daniel, Frederik, Jetty, and Vanessa were moderately resistant when combined data from all tests were analyzed. Results from this research permit the selection of more resistant breeding lines and also creates a baseline against which resistance of newly developed cultivars can be compared.

Susceptibility of Geranium Cultivars to Ralstonia solanacearum

Hortscience, 2009

Sixty-one cultivars of geraniums, including zonal, regal, iv. and scented, were tested for suscep... more Sixty-one cultivars of geraniums, including zonal, regal, iv. and scented, were tested for susceptibilit y to three strains of Ralsto,,ia so/al,acear:,m: a race I, biovar I (RIB]) strain P597 isolated from tomato in Florida, a RIBI strain P673 obtained from pothos originated from Costa Rica, and a race 3, biovar 2 (113132) strain UW551 isolated from geranium imported from Ken y a. These three strains represent populations of R. soianucearz,,, found in the United States or imported with infected plant propagative material. A genomic comparison of the geranium cultivars was also done using amplified fragment length polymorphisms. Both R1BI strains were more virulent than the R3132 strain, producing wilt symptoms on most cultivars of zonal, regal, and iv y types. Variation in susceptibilit y of geranium cultivars to the two RI BI strains was Ol)served. The R3B2 strain UW551 had a much more restricted host range and was not able to infect most regal geranium cultivars %%hen applied as a soil drench. Man y of the scented cultivars were found to be resistant to all three strains of R. solanacearu,n when tested using the drench inoculation method. However, most scented cultivars were found to be susceptible when plants were wound-inoculated. The greatest variation in t y pe of resistance was observed between the scented geranium cultivars and specific strains of R. solanacearu,,,.

Anthurium 'Show Biz

Hortscience, 2001

Comparative Effect of Low Temperature on Virulence and Twitching Motility of Ralstonia solanacearum Strains Present in Florida

Phytopathology, Sep 21, 2011

Curvilinear peristaltic pump having insertable tubing assembly

Accurate Corrosion Prediction through an Integrated Approach

Spe Prod Oper, 2007

Summary The ability to optimize the use of carbon steel in corrosive service presents many econom... more

Orange Hot' Anthurium

Hortscience, Feb 1, 2003

Additional index words. Anthurium andraeanum, Araceae, fl oricultural pro duc tion, foliage plant... more

Vapor-dominated fields: Fluid reserves and geothermometry

A vapor-dominated reservoir is modelled as a uniform porous medium containing immobile water and ... more

Analysis of Genetic Relatedness of Dieffenbachia Cultivars Using AFLP Markers

Journal of the American Society For Horticultural Science, 2004

ADDITIONAL INDEX WORDS. amplifi ed fragment length polymorphism, Araceae, Dieffenbachia breeding,... more ADDITIONAL INDEX WORDS. amplifi ed fragment length polymorphism, Araceae, Dieffenbachia breeding, dumb cane, ornamental tropical foliage plants ABSTRACT. Dieffenbachia Schott is an important ornamental foliage plant genus. A total of 30 species has been recognized, but most cultivars come from or are related to a single species, D. maculata (Lodd.) G. Don. At least 11 of the cultivars are sports or somaclonal variants. As a result, the potential lack of genetic diversity in cultivated Dieffenbachia has become a concern. However, no research has been conducted to determine the genetic relatedness of the cultivars. This study analyzed the genetic similarity of 42 Dieffenbachia cultivars using amplifi ed fragment length polymorphism (AFLP) markers. Six primer sets, selected from an initial screening of 48, generated a total of 453 scorable AFLP fragments of which 323 (71%) are polymorphic. All cultivars were clearly differentiated by their AFLP fi ngerprints. A dendrogram was constructed using the unweighted pair-group method of arithmetic averages, and principal coordinated analysis was carried out to show multiple dimensions of the distribution of the cultivars. The 42 cultivars were divided into three clusters; clusters I and II comprise 18 and 23 cultivars, respectively. Jaccardʼs similarity coeffi cients for cultivars in the clusters I and II varied from 0.44 to 0.95 and 0.41 to 0.87, respectively. These results indicate that broadening the genetic variability in the Dieffenbachia gene pool is needed, but the genetic similarity of many cultivars is not as close as previously thought. Additionally, Jaccardʼs similarity coeffi cients between most sports or somaclonal variants and their parents were 0.73 or lower, suggesting that accumulation of somatic mutations through tissue culture may play a role in the increased variation between some sports or variants and their parents.

A new hypothesis of dinosaur relationships and early dinosaur evolution

Nature, Mar 22, 2017

For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. ... more For 130 years, dinosaurs have been divided into two distinct clades-Ornithischia and Saurischia. Here we present a hypothesis for the phylogenetic relationships of the major dinosaurian groups that challenges the current consensus concerning early dinosaur evolution and highlights problematic aspects of current cladistic definitions. Our study has found a sister-group relationship between Ornithischia and Theropoda (united in the new clade Ornithoscelida), with Sauropodomorpha and Herrerasauridae (as the redefined Saurischia) forming its monophyletic outgroup. This new tree topology requires redefinition and rediagnosis of Dinosauria and the subsidiary dinosaurian clades. In addition, it forces re-evaluations of early dinosaur cladogenesis and character evolution, suggests that hypercarnivory was acquired independently in herrerasaurids and theropods, and offers an explanation for many of the anatomical features previously regarded as notable convergences between theropods and early...

Re-description of the postcranial skeleton of the middle Jurassic stegosaurHuayangosaurus taibaii

Journal of Vertebrate Paleontology, 2006

JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, a... more JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact

The phylogeny of the ornithischian dinosaurs

Journal of Systematic Palaeontology, 2008

SÁNCHEZ-VILLAGRA, M. R. & CLACK, J. A. (eds) 2004. Fossils of the Miocene Castillo Formation, Venezuela: Contributions in Neotropical Palaeontology. Special Papers in Palaeontology no. 71. 112 pp. London: The Palaeontological Association. Price £48.00 (paperback). ISBN 0 901702 82 X

Geological Magazine, 2005

Cranial design and function in a large theropod dinosaur

Nature, 2001

This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. Endnote Workbo... more This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 License. Endnote Workbook with exercises EndNote is software which enables you to: • Maintain a database (called a Library) of references • Import references from other databases • Embed references from the database into a word processed document • Produce bibliographies in an appropriate style for submission or publication.

ChemInform Abstract: ChemInform Abstract: Synthesis and Antifungal Properties of Benzylamines Containing Boronate Esters

Cheminform, 2002

ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance t... more ABSTRACT ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Status of Agricultural Economics in Selected Countries in Eastern and Southern Africa

Determinants of Kansas Farmers' Participation in On-Farm Research

Journal of Agricultural and Applied Economics, 1997

On-farm research (OFR) has increased in popularity in the U.S. in recent years due to heightened ... more On-farm research (OFR) has increased in popularity in the U.S. in recent years due to heightened interest in sustainability issues, the likely decline in resources available for agricultural research, and increasing pressures for accountability and responsiveness to state and local needs. Information relating to OFR was obtained from 431 commercial Kansas farmers. Data were analyzed to determine the degree of OFR being implemented, and three models were estimated to identify which farrner/farrn characteristics influenced its implementation, The results indicate that OFR is commonly implemented, and that several farm/farmer characteristics are related to the degree of OFR initiated. It is proposed that to maximize the return from externally initiated OFR, there would be merit in focusing attention on farms/farmers with those characteristics.

Resistance Levels of Pot Anthurium Cultivars to Xanthomonas campestris pv. dieffenbachiae

Hortscience, Jul 1, 1999

Additional index words. disease resistance, ornamental plant breeding Abstract. One cut-flower an... more Additional index words. disease resistance, ornamental plant breeding Abstract. One cut-flower and 14 pot anthurium cultivars were screened for resistance to anthurium blight by spraying four isolates of Xanthomonas campestris pv. dieffenbachiae (McCulloch and Pirone) Dye onto leaf surfaces in replicated experiments. Varying degrees of resistance were observed among the 15 cultivars tested. The pot cultivars Julia and Gemini were the most resistant, while the cut-flower cultivar Hearts Desire was the most susceptible. Each cultivar displayed different degrees of resistance to individual isolates of the pathogen. The results of this research permit the selection of clones with greater resistance for use in breeding and also create a baseline for comparing resistance of newly developed cultivars.

Satellite laser ranging using pseudonoise code modulated laser diodes

Applied Optics, Sep 1, 1988

Techniques for satellite laser ranging have historically employed high-energy pulsed lasers as th... more Techniques for satellite laser ranging have historically employed high-energy pulsed lasers as the optical transmitter. The output power currently available from laser diodes and laser diode arrays makes them a viable alternative to the pulsed laser for ranging applications. The modulation of a laser diode is examined by a pseudonoise code which produces a CW ranging signal with equivalent average power to that of current pulsed systems. A maximum-likelihood receiver for estimating signal arrival time using ideal rectangular pulses is shown to be a correlation receiver. A Cramer-Rao bound on the range error is derived for a ranging system with Gaussian code pulses and a correlation receiver. Ranging performance is evaluated for a single cube-corner retroreflector and a tilted flat diffuse target. It is shown that range accuracy of the order of 1 cm is feasible.

Classification and Identification of Xanthomonas translucens Isolates, Including Those Pathogenic to Ornamental Asparagus

Phytopathology, Aug 1, 2006

Rademaker, J. L. W., Norman, D. J., Forster, R. L., Louws, F. J., Schultz, M. H., and de Bruijn, ... more

Resistance in Twenty-two Cultivars of Spathiphyllum to Cylindrocladium Root Rot

Horttechnology, 1999

SUMMARY. Twenty-two spathiphyllum cultivars were evaluated for resistance to Cylindrocladium root... more SUMMARY. Twenty-two spathiphyllum cultivars were evaluated for resistance to Cylindrocladium root rot (CRR). Four isolates of the fungus Cylindrocladium spathiphylli Shoult., El-Gholl & Alf. were selected from two different locations each in Florida and Hawaii. Spores of isolates were applied as a soil drench in replicated experiments using a randomized complete block design. The most severe symptoms were those produced by C. spathiphylli isolates from Hawaii. None of the spathiphyllum cultivars tested were highly resistant to CRR although resistance among the cultivars was observed. The cultivars Chris and Textura were the most promising cultivars, having fairly uniform resistance to the four isolates of C. spathiphylli. The cultivars Cupido, Daniel, Frederik, Jetty, and Vanessa were moderately resistant when combined data from all tests were analyzed. Results from this research permit the selection of more resistant breeding lines and also creates a baseline against which resistance of newly developed cultivars can be compared.

Susceptibility of Geranium Cultivars to Ralstonia solanacearum

Hortscience, 2009

Sixty-one cultivars of geraniums, including zonal, regal, iv. and scented, were tested for suscep... more Sixty-one cultivars of geraniums, including zonal, regal, iv. and scented, were tested for susceptibilit y to three strains of Ralsto,,ia so/al,acear:,m: a race I, biovar I (RIB]) strain P597 isolated from tomato in Florida, a RIBI strain P673 obtained from pothos originated from Costa Rica, and a race 3, biovar 2 (113132) strain UW551 isolated from geranium imported from Ken y a. These three strains represent populations of R. soianucearz,,, found in the United States or imported with infected plant propagative material. A genomic comparison of the geranium cultivars was also done using amplified fragment length polymorphisms. Both R1BI strains were more virulent than the R3132 strain, producing wilt symptoms on most cultivars of zonal, regal, and iv y types. Variation in susceptibilit y of geranium cultivars to the two RI BI strains was Ol)served. The R3B2 strain UW551 had a much more restricted host range and was not able to infect most regal geranium cultivars %%hen applied as a soil drench. Man y of the scented cultivars were found to be resistant to all three strains of R. solanacearu,n when tested using the drench inoculation method. However, most scented cultivars were found to be susceptible when plants were wound-inoculated. The greatest variation in t y pe of resistance was observed between the scented geranium cultivars and specific strains of R. solanacearu,,,.

Anthurium 'Show Biz

Hortscience, 2001

Comparative Effect of Low Temperature on Virulence and Twitching Motility of Ralstonia solanacearum Strains Present in Florida

Phytopathology, Sep 21, 2011

Curvilinear peristaltic pump having insertable tubing assembly

Accurate Corrosion Prediction through an Integrated Approach

Spe Prod Oper, 2007

Summary The ability to optimize the use of carbon steel in corrosive service presents many econom... more

Orange Hot' Anthurium

Hortscience, Feb 1, 2003

Additional index words. Anthurium andraeanum, Araceae, fl oricultural pro duc tion, foliage plant... more

Vapor-dominated fields: Fluid reserves and geothermometry

A vapor-dominated reservoir is modelled as a uniform porous medium containing immobile water and ... more

Analysis of Genetic Relatedness of Dieffenbachia Cultivars Using AFLP Markers

Journal of the American Society For Horticultural Science, 2004

ADDITIONAL INDEX WORDS. amplifi ed fragment length polymorphism, Araceae, Dieffenbachia breeding,... more ADDITIONAL INDEX WORDS. amplifi ed fragment length polymorphism, Araceae, Dieffenbachia breeding, dumb cane, ornamental tropical foliage plants ABSTRACT. Dieffenbachia Schott is an important ornamental foliage plant genus. A total of 30 species has been recognized, but most cultivars come from or are related to a single species, D. maculata (Lodd.) G. Don. At least 11 of the cultivars are sports or somaclonal variants. As a result, the potential lack of genetic diversity in cultivated Dieffenbachia has become a concern. However, no research has been conducted to determine the genetic relatedness of the cultivars. This study analyzed the genetic similarity of 42 Dieffenbachia cultivars using amplifi ed fragment length polymorphism (AFLP) markers. Six primer sets, selected from an initial screening of 48, generated a total of 453 scorable AFLP fragments of which 323 (71%) are polymorphic. All cultivars were clearly differentiated by their AFLP fi ngerprints. A dendrogram was constructed using the unweighted pair-group method of arithmetic averages, and principal coordinated analysis was carried out to show multiple dimensions of the distribution of the cultivars. The 42 cultivars were divided into three clusters; clusters I and II comprise 18 and 23 cultivars, respectively. Jaccardʼs similarity coeffi cients for cultivars in the clusters I and II varied from 0.44 to 0.95 and 0.41 to 0.87, respectively. These results indicate that broadening the genetic variability in the Dieffenbachia gene pool is needed, but the genetic similarity of many cultivars is not as close as previously thought. Additionally, Jaccardʼs similarity coeffi cients between most sports or somaclonal variants and their parents were 0.73 or lower, suggesting that accumulation of somatic mutations through tissue culture may play a role in the increased variation between some sports or variants and their parents.