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Full-Text Articles in Social and Behavioral Sciences

Single-Grain Osl Chronologies For Middle Palaeolithic Deposits At El Mnasra And El Harhoura 2, Morocco: Implications For Late Pleistocene Human-Environment Interactions Along The Atlantic Coast Of Northwest Africa, Zenobia Jacobs, Richard Roberts, Roland Nespoulet, M El Hajraoui, Andre Debenath Mar 2013

Single-Grain Osl Chronologies For Middle Palaeolithic Deposits At El Mnasra And El Harhoura 2, Morocco: Implications For Late Pleistocene Human-Environment Interactions Along The Atlantic Coast Of Northwest Africa, Zenobia Jacobs, Richard Roberts, Roland Nespoulet, M El Hajraoui, Andre Debenath

Richard G Roberts

Optically stimulated luminescence (OSL) measurements were made on individual, sand-sized grains of quartz from Middle Palaeolithic deposits at two cave sites (El Harhoura 2 and El Mnasra) on the Atlantic coast of Morocco. We were able to calculate OSL ages for 32 of the 33 samples collected from the Middle Palaeolithic deposits, including the earliest and latest Aterian levels at both sites. These ages reveal periods of occupation between about 110 and 95 ka (thousands of years ago), and at ~75 ka. A late Middle Palaeolithic occupation of El Harhoura 2 is also recorded at ~55 ka. Our single-grain OSL …


Testing Times: Old And New Chronologies For The Howieson's Poort And Still Bay Industries In Environmental Context, Richard Roberts, Zenobia Jacobs Mar 2013

Testing Times: Old And New Chronologies For The Howieson's Poort And Still Bay Industries In Environmental Context, Richard Roberts, Zenobia Jacobs

Richard G Roberts

No abstract provided.


Dating The Quaternary: Progress In Luminescence Dating Of Sediments, Richard Roberts, O Lian Mar 2013

Dating The Quaternary: Progress In Luminescence Dating Of Sediments, Richard Roberts, O Lian

Richard G Roberts

No abstract provided.


Melting Ice Sheets 400,000 Yr Ago Raised Sea Level By 13 M: Past Analogue For Future Trends, David Roberts, Panagiotis Karkanas, Zenobia Jacobs, Curtis Marean, Richard Roberts Mar 2013

Melting Ice Sheets 400,000 Yr Ago Raised Sea Level By 13 M: Past Analogue For Future Trends, David Roberts, Panagiotis Karkanas, Zenobia Jacobs, Curtis Marean, Richard Roberts

Richard G Roberts

Marine Isotope Stage (MIS) 11 was possibly the longest (∼423,000–362,000 yr ago) and warmest interglacial of the entire Quaternary Period. This resulted from a special arrangement of Earth's orbital parameters-similar to the present interglacial (MIS 1)-suggesting that MIS 11 provides an analogue for future natural climate forcing and sea levels. Although precise documentation of MIS 11 sea level history is, therefore, crucial – especially considering additional impetus from anthropogenic warming – the maximum MIS 11 sea level remains highly contentious. Estimates from onshore indicators have ranged from below present sea level to about +20 m, resulting from uncertainties in reliability …


Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler Mar 2013

Single-Grain Optical Dating Of Grave-Infill Associated With Human Burials At Lake Mungo Australia, Jonathon Olley, Richard Roberts, Hiroyuki Yoshida, James M Bowler

Richard G Roberts

Recent age constraints on Australia's oldest human remains (Mungo I and III), found at Lake Mungo in western New South Wales, relied on optical dating of sands from the same stratigraphic units as those into which the remains had been inserted (42±3 ka) and those that overlay the graves (38±2 ka), giving a burial age of 40±2 ka. This indirect means of dating the burials was necessary because the original site from which the remains had been excavated had been completely eroded away. At the time of the original excavation of the Mungo III grave, blocks of sediment from the …


Error Variation In Osl Palaeodose Estimates From Singles Aliquots Of Quartz: A Factorial Experiment, Richard Roberts, R.F. Galbraith, Hiroyuki Yoshida Mar 2013

Error Variation In Osl Palaeodose Estimates From Singles Aliquots Of Quartz: A Factorial Experiment, Richard Roberts, R.F. Galbraith, Hiroyuki Yoshida

Richard G Roberts

No abstract provided.


Middle Paleolithic Occupation On A Marine Isotope Stage 5 Lakeshore In The Nefud Desert, Saudi Arabia, Michael Petraglia, Abdullah Alsharekh, Remy Crassard, Nick Drake, Huw Groucutt, Adrian Parker, Richard Roberts Mar 2013

Middle Paleolithic Occupation On A Marine Isotope Stage 5 Lakeshore In The Nefud Desert, Saudi Arabia, Michael Petraglia, Abdullah Alsharekh, Remy Crassard, Nick Drake, Huw Groucutt, Adrian Parker, Richard Roberts

Richard G Roberts

No abstract provided.


Homo Floresiensis And The Late Pleistocene Environments Of Eastern Indonesia: Defining The Nature Of The Relationship, Kira Westaway, M Morwood, T. Sutikna, M. Moore, A. Rokus, G Van Den Bergh, Richard Roberts, E. Saptomo Mar 2013

Homo Floresiensis And The Late Pleistocene Environments Of Eastern Indonesia: Defining The Nature Of The Relationship, Kira Westaway, M Morwood, T. Sutikna, M. Moore, A. Rokus, G Van Den Bergh, Richard Roberts, E. Saptomo

Richard G Roberts

No abstract provided.


Hominin Dispersal Into The Nefud Desert And Middle Palaeolithic Settlement Along The Jubbah Palaeolake, Northern Arabia, M Petraglia, Abdullah M. Alsharekh, P Breeze, Christopher Clarkson, Remy Crassard, Nick A. Drake, Huw Groucutt, R Jennings, Adrian Parker, A Parton, Richard Roberts, C Shipton, Carney Matheson, A Al-Omari, M Veall Mar 2013

Hominin Dispersal Into The Nefud Desert And Middle Palaeolithic Settlement Along The Jubbah Palaeolake, Northern Arabia, M Petraglia, Abdullah M. Alsharekh, P Breeze, Christopher Clarkson, Remy Crassard, Nick A. Drake, Huw Groucutt, R Jennings, Adrian Parker, A Parton, Richard Roberts, C Shipton, Carney Matheson, A Al-Omari, M Veall

Richard G Roberts

The Arabian Peninsula is a key region for understanding hominin dispersals and the effect of climate change on prehistoric demography, although little information on these topics is presently available owing to the poor preservation of archaeological sites in this desert environment. Here, we describe the discovery of three stratified and buried archaeological sites in the Nefud Desert, which includes the oldest dated occupation for the region. The stone tool assemblages are identified as a Middle Palaeolithic industry that includes Levallois manufacturing methods and the production of tools on flakes. Hominin occupations correspond with humid periods, particularly Marine Isotope Stages 7 …


Middle Paleolithic Assemblages From The Indian Subcontinent, Before And After The Toba Super-Eruption, Michael Petraglia, Ravi Korisettar, Nicole Boivin, Christopher Clarkson, Peter Ditchfield, Sacha Jones, Jinu Koshy, Marta Lahr, Clive Oppenheimer, David Pyle, Richard Roberts, Jean-Luc Schwenninger, Lee Arnold, Kevin White Mar 2013

Middle Paleolithic Assemblages From The Indian Subcontinent, Before And After The Toba Super-Eruption, Michael Petraglia, Ravi Korisettar, Nicole Boivin, Christopher Clarkson, Peter Ditchfield, Sacha Jones, Jinu Koshy, Marta Lahr, Clive Oppenheimer, David Pyle, Richard Roberts, Jean-Luc Schwenninger, Lee Arnold, Kevin White

Richard G Roberts

The Youngest Toba Tuff (YTT) eruption, which occurred in Indonesia 74,000 years ago, is one of Earth's largest known volcanic events. The effect of the YTT eruption on existing populations of humans, and accordingly on the course of human evolution, is debated. Here we associate the YTT with archaeological assemblages at Jwalapuram, in the Jurreru River valley of southern India. Broad continuity of Middle Paleolithic technology across the YTT event suggests that hominins persisted regionally across this major eruptive event.


Dirt, Dates And Dna:Osl And Radiocarbon Chronologies Of Perenially Frozen Sediments In Siberia, And Their Implications For Sedimentary Ancient Dna Studies, Lee Arnold, Richard Roberts, Ross Macphee, James Haile, Fiona Brock, Per Moller, Duane Froese, Alexei Tikhonov, Allan Chivas, M. Thomas Gilbert, Eske Willerslev Mar 2013

Dirt, Dates And Dna:Osl And Radiocarbon Chronologies Of Perenially Frozen Sediments In Siberia, And Their Implications For Sedimentary Ancient Dna Studies, Lee Arnold, Richard Roberts, Ross Macphee, James Haile, Fiona Brock, Per Moller, Duane Froese, Alexei Tikhonov, Allan Chivas, M. Thomas Gilbert, Eske Willerslev

Richard G Roberts

The sedimentary ancient DNA (sedaDNA) technique offers a potentially invaluable means of investigating species evolution and extinction dynamics in high-latitude environments. An implicit assumption of the sedaDNA approach is that the extracted DNA is autochthonous with the host deposit and that it has not been physically transported from older source deposits or reworked within the sedimentary profile by postdepositional mixing. In this paper we investigate whether these fundamental conditions are upheld at seven perennially frozen wetland sites across the Taimyr Peninsula and coastal lowlands of north-central Siberia. Optically stimulated luminescence (OSL) and radiocarbon (14C) dating are used to constrain the …


A Dual-Aliquot Regenerative-Dose Protocol (Dap) For Thermoluminescence (Tl) Dating Of Quartz Sediments Using The Light-Sensitive And Isothermally Stimulated Red Emissions, Richard Roberts, Kira Westaway Mar 2013

A Dual-Aliquot Regenerative-Dose Protocol (Dap) For Thermoluminescence (Tl) Dating Of Quartz Sediments Using The Light-Sensitive And Isothermally Stimulated Red Emissions, Richard Roberts, Kira Westaway

Richard G Roberts

No abstract provided.


A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong Mar 2013

A Revised Burial Dose Estimation Procedure For Optical Dating Of Young And Modern-Age Sediments, Richard Roberts, Lee Arnold, R.F. Galbraith, S Delong

Richard G Roberts

No abstract provided.


An Arid-Adapted Middle Pleistocene Vertebrate Fauna From South-Central Australia, Richard Roberts, Lee Arnold, John Hellstrom, Gavin Prideaux, Mark Hutchinson, Linda Ayliffe, Walter Boles, Matthew Cupper, Paul Devine, Brad Pillans, John Long Mar 2013

An Arid-Adapted Middle Pleistocene Vertebrate Fauna From South-Central Australia, Richard Roberts, Lee Arnold, John Hellstrom, Gavin Prideaux, Mark Hutchinson, Linda Ayliffe, Walter Boles, Matthew Cupper, Paul Devine, Brad Pillans, John Long

Richard G Roberts

No abstract provided.


Turning Back The Clock On The Extinction Of Megafauna In Australia, Richard Roberts, Barry Brook Mar 2013

Turning Back The Clock On The Extinction Of Megafauna In Australia, Richard Roberts, Barry Brook

Richard G Roberts

No abstract provided.


Late Acheulean Hominins At The Marine Isotope Stage 6/5e Transition In North-Central India, Michael Haslam, Richard Roberts, Ceri Shipton, J Pal, Jacqueline Fenwick, Peter Ditchfield, Nicole Boivin, A Dubey, M Gupta, Michael Petraglia Mar 2013

Late Acheulean Hominins At The Marine Isotope Stage 6/5e Transition In North-Central India, Michael Haslam, Richard Roberts, Ceri Shipton, J Pal, Jacqueline Fenwick, Peter Ditchfield, Nicole Boivin, A Dubey, M Gupta, Michael Petraglia

Richard G Roberts

Single-grain optically stimulated luminescence dating was applied to Late Quaternary sediments at two sites in the Middle Son Valley, Madhya Pradesh, India. Designated Bamburi 1 and Patpara, thesse sites contain Late Acheulean stone tool assemblages, which we associate with non-modern hominins. Age determinations of 140-120. ka place the formation of these sites at around the Marine Oxygen Isotope Stage 6-5 transition, placing them among the youngest Acheulean sites in the world. We present here the geochronology and sedimentological setting of these sites, and consider potential implications of Late Pleistocene archaic habitation in north-central India for the initial dispersal of modern …


And Then There Were None?, Richard G. Roberts, Barry W. Brook Mar 2013

And Then There Were None?, Richard G. Roberts, Barry W. Brook

Richard G Roberts

No abstract provided.


Illuminating Southeast Asian Prehistory : New Archaeological And Paleoanthropological Frontiers For Luminescence Dating, Richard G. Roberts, Michael J. Morwood, Kira E. Westaway Mar 2013

Illuminating Southeast Asian Prehistory : New Archaeological And Paleoanthropological Frontiers For Luminescence Dating, Richard G. Roberts, Michael J. Morwood, Kira E. Westaway

Richard G Roberts

Since the explorations of Alfred Russel Wallace and Eugène Dubois in the nineteenth century, Southeast Asia has been one of the world's focal points for studies of biogeography and biodiversity, human evolution and dispersal, environmental change, and the spread of culture, farming, and language. Yet despite its prominence, reliable chronologies are not available for many of the critical archaeological, evolutionary, and environmental turning points that have taken place in the region during the last 1.5 million years. In this paper, we discuss some of these chronological problems and describe how luminescence dating may help overcome them. "Luminescence dating" is a …


The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas Mar 2013

The Evolving Landscape And Climate Of Western Flores: An Environmental Context For The Archaeological Site Of Liang Bua, Kira Westaway, Richard Roberts, T Sutikna, Michael Morwood, R Drysdale, J Zhao, Allan Chivas

Richard G Roberts

The rapidly changing landscape of the eastern Indonesian archipelago has evolved at a pace dictated by its tropical climate and its geological and tectonic history. This has produced accelerated karstification, flights of alluvial terraces, and complex, multi-level cave systems. These cave systems sometimes contain a wealth of archaeological evidence, such as the almost complete skeleton of Homo floresiensis found at the site of Liang Bua in western Flores, but this information can only be understood in the context of the geomorphic history of the cave, and the more general geological, tectonic, and environmental histories of the river valley and region. …


Advances In Optically Stimulated Luminescence Dating Of Individual Grains Of Quartz From Archaeological Deposits, Richard Roberts, Zenobia Jacobs Mar 2013

Advances In Optically Stimulated Luminescence Dating Of Individual Grains Of Quartz From Archaeological Deposits, Richard Roberts, Zenobia Jacobs

Richard G Roberts

No abstract provided.


Afromontane Foragers Of The Late Pleistocene: Site Formation, Chronology And Occupational Pulsing At Melikane Rockshelter, Lesotho, Brian Stewart, Genevieve Dewar, Mike Morley, Robyn Inglis, Mark Wheeler, Zenobia Jacobs, Richard Roberts Mar 2013

Afromontane Foragers Of The Late Pleistocene: Site Formation, Chronology And Occupational Pulsing At Melikane Rockshelter, Lesotho, Brian Stewart, Genevieve Dewar, Mike Morley, Robyn Inglis, Mark Wheeler, Zenobia Jacobs, Richard Roberts

Richard G Roberts

This paper provides a preliminary chronostratigraphic and palaeoenvironmental framework for the Late Pleistocene archaeological sequence at Melikane Rockshelter in mountainous eastern Lesotho. Renewed excavations at Melikane form part of a larger project investigating marginal landscape use by Late Pleistocene foragers in southern Africa. Geoarchaeological work undertaken at the site supports in-field observations that Melikane experienced regular, often intensive, input of groundwater via fissures in the shelter’s rear wall. This strong hydrogeological connection resulted in episodic disturbances of the sedimentary sequence, exacerbated by other processes such as bioturbation. Despite this taphonomic complexity, a robust chronology for Melikane has been developed, based …


Luminescence Characteristics And Dose Distributions For Quartz And Feldspar Grains From Mumba Rockshelter, Tanzania, Luke Gliganic, Zenobia Jacobs, Richard Roberts Mar 2013

Luminescence Characteristics And Dose Distributions For Quartz And Feldspar Grains From Mumba Rockshelter, Tanzania, Luke Gliganic, Zenobia Jacobs, Richard Roberts

Richard G Roberts

Mumba rockshelter is a key archaeological site for the Middle and Later Stone Age occupation of East Africa, but its chronology has remained unresolved. We report the results of a dating study, focussing on the characterisation of the optically stimulated luminescence (OSL) and infrared stimulated luminescence (IRSL) properties of quartz- and potassium-rich feldspar grains. Quartz has previously proven troublesome for dating in East Africa. We identified five general types of quartz grain behaviour, based on the shapes of their OSL decay and dose–response curves. Dose recovery experiments and measurement of the natural samples revealed particular problems with quartz grains that …


The Nubian Complex Of Dhofar, Oman: An African Middle Stone Age Industry In Southern Arabia, Jeffrey I. Rose, Vitaly I. Usik, Anthony E. Marks, Yamandu H. Hilbert, Christopher S. Galletti, Ash Parton, Jean Marie Geiling, Viktor Cerny, Mike W. Morley, Richard Roberts Mar 2013

The Nubian Complex Of Dhofar, Oman: An African Middle Stone Age Industry In Southern Arabia, Jeffrey I. Rose, Vitaly I. Usik, Anthony E. Marks, Yamandu H. Hilbert, Christopher S. Galletti, Ash Parton, Jean Marie Geiling, Viktor Cerny, Mike W. Morley, Richard Roberts

Richard G Roberts

Despite the numerous studies proposing early human population expansions from Africa into Arabia during the Late Pleistocene, no archaeological sites have yet been discovered in Arabia that resemble a specific African industry, which would indicate demographic exchange across the Red Sea. Here we report the discovery of a buried site and more than 100 new surface scatters in the Dhofar region of Oman belonging to a regionally-specific African lithic industry - the late Nubian Complex - known previously only from the northeast and Horn of Africa during Marine Isotope Stage 5, ~128,000 to 74,000 years ago. Two optically stimulated luminescence …


Single-Grain Osl Dating At La Grotte Des Contrebandiers ('Smugglers' Cave'), Morocco: Improved Age Constraints For The Middle Paleolithic Levels, Richard Roberts, Zenobia Jacobs, Michael Meyer, V Aldeias, M El Hajraoui, H Dibbie Mar 2013

Single-Grain Osl Dating At La Grotte Des Contrebandiers ('Smugglers' Cave'), Morocco: Improved Age Constraints For The Middle Paleolithic Levels, Richard Roberts, Zenobia Jacobs, Michael Meyer, V Aldeias, M El Hajraoui, H Dibbie

Richard G Roberts

Optically stimulated luminescence (OSL) measurements of individual quartz grains are reported for Middle Paleolithic (MP) or Middle Stone Age (MSA) deposits in La Grotte des Contrebandiers, Morocco. Single-grain measurements enable rejection of grains that may lead to under- or over-estimation of age due to malign luminescence properties or remobilisation of grains after burial. We identified the former using a range of experimental procedures and objective rejection criteria. Three post-depositional factors influenced the distribution pattern of equivalent dose (De) values for the remaining single grains: the disintegration of roof spall liberating unbleached, older grains into otherwise well-bleached sediments; the intrusion of …


Updating The Dietadvice Website With New Australian Food Composition Data, Yasmine Probst, Holley-Anne Jones, Shannon Lin, S. Burden, David G. Steel, Linda C. Tapsell Dec 2012

Updating The Dietadvice Website With New Australian Food Composition Data, Yasmine Probst, Holley-Anne Jones, Shannon Lin, S. Burden, David G. Steel, Linda C. Tapsell

Professor David Steel

DietAdvice is an Australian self-administered dietary assessment website initially developed in 2003- 2005. The website allows patients to enter their dietary information and dieticians to remotely access and interpret the data. DietAdvice is presently being updated with new Australian food composition data. This study aims to describe the update process for moving from 1995 to 2006 food composition data. The database for the website was developed using grouped food data from the NUTTAB 1995 database. All food groups were cross-matched with the food from the NUTTAB 2006 database using the food ID codes. Rules were applied to determine the suitability …


Video-Recorded Usability Testing Of A Web-Based Self-Administered Dietary Assessment, Yasmine Probst, David Steel, Linda Tapsell Dec 2012

Video-Recorded Usability Testing Of A Web-Based Self-Administered Dietary Assessment, Yasmine Probst, David Steel, Linda Tapsell

Professor David Steel

No abstract provided.


Air-Drying Of Banana: Influence Of Experimental Parameters, Slab Thickness, Banana Maturity And Harvesting Season, Minh-Hue Nguyen, William E. Price Oct 2012

Air-Drying Of Banana: Influence Of Experimental Parameters, Slab Thickness, Banana Maturity And Harvesting Season, Minh-Hue Nguyen, William E. Price

William E. Price

Air-drying of banana slabs has been investigated and the influence of experimental parameters such as temperature, relative humidity and slab thickness has been studied. This was in part re-investigated because of inconsistencies in previous studies, particularly in relation to derived water diffusion coefficients. In addition, it is shown that harvest season and hence initial moisture content has a very marked influence on the drying kinetics. By contrast banana maturity (ripeness) has little influence on the kinetics despite there being significant differences in morphology and chemical composition between green and ripe bananas. The effect of these two variables on the drying …


Increased Probiotic Yogurt Or Resistant Starch Intake Does Not Affect Isoflavone Bioavailability In Subjects Consuming A High Soy Diet, Theresa A. Larkin, William E. Price, Lee B. Astheimer Oct 2012

Increased Probiotic Yogurt Or Resistant Starch Intake Does Not Affect Isoflavone Bioavailability In Subjects Consuming A High Soy Diet, Theresa A. Larkin, William E. Price, Lee B. Astheimer

William E. Price

Objective: Probiotics and prebiotics that affect gut microflora balance and its associated enzymeactivity may contribute to interindividual variation in isoflavone absorption after soy intake, possiblyenhancing isoflavone bioavailability. This study examined the effects of the consumption ofbioactive yogurt (a probiotic) or resistant starch (a known prebiotic) in combination with high soyintake on soy isoflavone bioavailability.Methods: Using a crossover design, chronic soy consumption was compared with soy plusprobiotic yogurt or resistant starch in older male and postmenopausal females (n 31). Isoflavonebioavailability was assessed at the beginning and end of each 5-wk dietary period by samplingplasma and urine after a standardized soy meal.Results: …


Fractionation Of Sedimentary Arsenic From Port Kembla Harbour, Nsw, Australia, Glennys A. O'Brien, William E. Price, Bryan E. Chenhall, Muhammad Damris Oct 2012

Fractionation Of Sedimentary Arsenic From Port Kembla Harbour, Nsw, Australia, Glennys A. O'Brien, William E. Price, Bryan E. Chenhall, Muhammad Damris

William E. Price

The binding of arsenic in sediments of the heavily industrialised Port Kembla Harbour, NSW, Australia, has been investigated. Both dredge and core samples have been used to develop a sieving/sequential extraction (SE) procedure. Dredge samples included oxic surficial and deeper anoxic sediment. The main core sample analysed was 18 cm deep, sliced at 2 cm intervals. Sediment was sieved to three size ranges (250 microm) and each of these was then subjected to a four step SE, sequentially solubilizing arsenic as ion exchangeable, 1 M HCl soluble, NH(2)OH.HCl soluble, and strong oxidising acid soluble. Concentrations of 50-500 mg As kg(-1) …


A Fragmentation Study Of Isoflavones In Negative Electrospray Ionization By Msn Ion Trap Mass Spectrometry And Triple Quadrupole Mass Spectrometry, Jinguo Kang, Larry A. Hick, William E. Price Oct 2012

A Fragmentation Study Of Isoflavones In Negative Electrospray Ionization By Msn Ion Trap Mass Spectrometry And Triple Quadrupole Mass Spectrometry, Jinguo Kang, Larry A. Hick, William E. Price

William E. Price

This study has elucidated the fragmentation pathway for deprotonated isoflavones in electrospray ionization using MSn ion trap mass spectrometry and triple quadrupole mass spectrometry. Genistein-d4 and daidzein-d3 were used as references for the clarification of fragment structures. To confirm the relationship between precursor and product ions, some fragments were traced from MS2 to MS5. The previous literature for the structurally related flavones and flavanones located the loss of ketene (C2H2O) to ring C, whereas the present fragmentation study for isoflavones has shown that the loss of ketene occurs elsewhere at ring A. In the further fragmentation of the [M-H-CH3]•- radical …