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Full-Text Articles in Physical Sciences and Mathematics
Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark
Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark
Professor David Steel
The well known Godambe-Joshi lower bound for the anticipated variance of design unbiased estimators of population totals treats the auxiliary variables as constants. We extend the result to models where these variables are random and show that the generalized difference estimator using the expected values conditional on all auxiliary values is optimal. This has several implications including the fact that collecting multiple survey variables does not reduce the lower bound.
Scales, Levels And Processes: Studying Spatial Patterns Of British Census Variables, David Manley, Robin Flowerdew, David Steel
Scales, Levels And Processes: Studying Spatial Patterns Of British Census Variables, David Manley, Robin Flowerdew, David Steel
Professor David Steel
No abstract provided.
Measuring And Analysing Homogeneity Of Geographical Areas For A Categorical Variable, David Steel, Mark Tranmer
Measuring And Analysing Homogeneity Of Geographical Areas For A Categorical Variable, David Steel, Mark Tranmer
Professor David Steel
Many Variables have within group homogeneity (similarity of values for the individual units that comprise the groups). Measures of within group homogeneity are useful for the sample design and statistical analysis of datasets for populations that contain groups, such as individuals in geographical areas. Homogeneity measures can easily be defined for continuous or dichotomous variables. Here we propose a homogeneity measure for a multi-category variable and show how this measure can be calculated without access to individual level data. We apply the measure to data from the UK census and show how this measure can be related to the homogeneity …
Progress In Optical Dating Of Guano-Rich Sediments Associated With The Deep Skull, West Mouth Of The Great Cave Of Niah, Sarawak, Borneo, Mark Stephens, Richard Roberts, O Lian, Hiroyuki Yoshida
Progress In Optical Dating Of Guano-Rich Sediments Associated With The Deep Skull, West Mouth Of The Great Cave Of Niah, Sarawak, Borneo, Mark Stephens, Richard Roberts, O Lian, Hiroyuki Yoshida
Richard G Roberts
The West Mouth of the Great Cave of Niah is one of the major archaeological sites in Southeast Asia; the radiocarbon chronology of this site currently places the earliest presence of Homo sapiens (a Deep Skull find) in Southeast Asia at about 45 ka BP. An optical dating programme using sand-sized quartz was initiated in the West Mouth to complement the radiocarbon chronology. This paper reports on the progress in dating a key sample (sample 376r) that was taken from deposits containing the Deep Skull. A somewhat novel procedure was developed to separate and clean quartz grains from the unusual …
Further Evidence For Small-Bodied Hominins From The Late Pleistocene Of Flores Indonesia, Michael Morwood, P. Brown, Jatmiko, T. Sutikna, E.W. Saptomo, Kira Westaway, R. A. Due, Richard Roberts, T Maeda, S Wasisto, T Djubiantono
Further Evidence For Small-Bodied Hominins From The Late Pleistocene Of Flores Indonesia, Michael Morwood, P. Brown, Jatmiko, T. Sutikna, E.W. Saptomo, Kira Westaway, R. A. Due, Richard Roberts, T Maeda, S Wasisto, T Djubiantono
Richard G Roberts
Homo floresiensis was recovered from Late Pleistocene deposits on the island of Flores in eastern Indonesia, but has the stature, limb proportions and endocranial volume of African Pliocene Australopithecus 1. The holotype of the species (LB1), excavated in 2003 from Liang Bua, consisted of a partial skeleton minus the arms. Here we describe additional H. floresiensis remains excavated from the cave in 2004. These include arm bones belonging to the holotype skeleton, a second adult mandible, and postcranial material from other individuals. We can now reconstruct the body proportions of H. floresiensis with some certainty. The finds further demonstrate …
Sediment Mixing At Nonda Rock: Investigations Of Stratigraphic Integrity At An Early Archaeological Site In Northern Australia And Implications For The Human Colonisation Of The Continent, Richard Roberts, C White, L K Fifield, Christian Turney, M Bird, John Tibby, Bruno David, John Magee, Jerome Mialanes
Sediment Mixing At Nonda Rock: Investigations Of Stratigraphic Integrity At An Early Archaeological Site In Northern Australia And Implications For The Human Colonisation Of The Continent, Richard Roberts, C White, L K Fifield, Christian Turney, M Bird, John Tibby, Bruno David, John Magee, Jerome Mialanes
Richard G Roberts
No abstract provided.
Holocene Palaeofire Records In A High-Level, Proximal Valley-Fill (Wilson Bog), Mount Lofty Ranges, South Australia, Solomon Buckman, Katherine Brownlie, Robert Bourman, C. Murray-Wallace, Rowena Morris, Terry Lachlan, Richard Roberts, Lee Arnold, J. Cann
Holocene Palaeofire Records In A High-Level, Proximal Valley-Fill (Wilson Bog), Mount Lofty Ranges, South Australia, Solomon Buckman, Katherine Brownlie, Robert Bourman, C. Murray-Wallace, Rowena Morris, Terry Lachlan, Richard Roberts, Lee Arnold, J. Cann
Richard G Roberts
No abstract provided.
Times Of Sand: Sedimentary History And Archaeology At The Sigatoka Dunes, Fiji, Richard Roberts, Geoffrey Hope, Antoine De Biran, Patrick Nunn, Atholl Anderson, William Dickinson, David Burley, Geoffrey Clark
Times Of Sand: Sedimentary History And Archaeology At The Sigatoka Dunes, Fiji, Richard Roberts, Geoffrey Hope, Antoine De Biran, Patrick Nunn, Atholl Anderson, William Dickinson, David Burley, Geoffrey Clark
Richard G Roberts
No abstract provided.
Equivalent Dose Distributions From Single Grains Of Quartz At Sibudu, South Africa: Context, Causes And Consequences For Optical Dating Of Archaeological Deposits, Richard Roberts, Zenobia Jacobs, Geoffrey Duller, Ann Wintle
Equivalent Dose Distributions From Single Grains Of Quartz At Sibudu, South Africa: Context, Causes And Consequences For Optical Dating Of Archaeological Deposits, Richard Roberts, Zenobia Jacobs, Geoffrey Duller, Ann Wintle
Richard G Roberts
No abstract provided.
Mammalian Responses To Pleistocene Climate Change In Southeastern Australia, Richard Roberts, Jonathon Olley, John Hellstrom, Dirk Megirian, Gavin Prideaux, Kira Westaway
Mammalian Responses To Pleistocene Climate Change In Southeastern Australia, Richard Roberts, Jonathon Olley, John Hellstrom, Dirk Megirian, Gavin Prideaux, Kira Westaway
Richard G Roberts
No abstract provided.
Late-Surviving Megafauna In Tasmania Australia, Implicate Human Involvement In Their Extinction, Christian Turney, T Flannery, Richard Roberts, Craig Reid, Keith Fifield, T Higham, Zenobia Jacobs, Noel Kemp, Eric Colhoun, R.M. Kalin
Late-Surviving Megafauna In Tasmania Australia, Implicate Human Involvement In Their Extinction, Christian Turney, T Flannery, Richard Roberts, Craig Reid, Keith Fifield, T Higham, Zenobia Jacobs, Noel Kemp, Eric Colhoun, R.M. Kalin
Richard G Roberts
Establishing the cause of past extinctions is critical if we are to understand better what might trigger future occurrences and how to prevent them. The mechanisms of continental late Pleistocene megafaunal extinction, however, are still fiercely contested. Potential factors contributing to their demise include climatic change, human impact, or some combination. On the Australian mainland, 90% of the megafauna became extinct by ≈46 thousand years (ka) ago, soon after the first archaeological evidence for human colonization of the continent. Yet, on the neighboring island of Tasmania (which was connected to the mainland when sea levels were lower), megafaunal extinction appears …
Evolutionary Anthropology - Homo 'Incendius', Richard Roberts, Michael Bird
Evolutionary Anthropology - Homo 'Incendius', Richard Roberts, Michael Bird
Richard G Roberts
Humans have long been captivated by the flickering flames of the campfire. But when did our ancestors first master the use of fire, and which ancient human species was the first to do so? In Proceedings of the National Academy of Sciences, Berna and colleagues1 report that they have found fragments of burnt bone and ashed plants in one-million-year-old sediments at Wonderwerk Cave, Northern Cape province, South Africa. This evidence of fire occurs in the same sedimentary layers as Acheulian stone tools, usually considered the handiwork of Homo erectus. Their discovery more than doubles the accepted antiquity of the habitual …
The Cyrenaican Prehistory Project 2008: The Second Season Of Investigations Of The Haua Fteah Cave And Its Landscape, And Further Results From The Initial (2007) Fieldwork, Richard Roberts, Zenobia Jacobs, Johnny Morales, M. Morley, R. Grun, L Farr, C Hunt, G Barker, R Rabett, T Reynolds, Victoria Leitch, Robyn Inglis, Roisin Hamilton, John Davison, Hwedi El-Rishi, Alex Pryor, David Simpson, Marijke Van Der Veen, Chris Stimpson, Steven Pawley, Mohammed Touati, Caroline Cartwright, Franca Cole, Iain Morley, Lucilla Burn, Ian Brooks, Laura Basell
The Cyrenaican Prehistory Project 2008: The Second Season Of Investigations Of The Haua Fteah Cave And Its Landscape, And Further Results From The Initial (2007) Fieldwork, Richard Roberts, Zenobia Jacobs, Johnny Morales, M. Morley, R. Grun, L Farr, C Hunt, G Barker, R Rabett, T Reynolds, Victoria Leitch, Robyn Inglis, Roisin Hamilton, John Davison, Hwedi El-Rishi, Alex Pryor, David Simpson, Marijke Van Der Veen, Chris Stimpson, Steven Pawley, Mohammed Touati, Caroline Cartwright, Franca Cole, Iain Morley, Lucilla Burn, Ian Brooks, Laura Basell
Richard G Roberts
No abstract provided.
New Excavations Of Middle Stone Age Deposits At Apollo 11 Rockshelter, Namibia: Stratigraphy, Archaeology, Chronology And Past Environments, Ralf Vogelsang, Jurgen Richter, Zenobia Jacobs, Barbara Eichhorn, Veerle Linseele, Richard Roberts
New Excavations Of Middle Stone Age Deposits At Apollo 11 Rockshelter, Namibia: Stratigraphy, Archaeology, Chronology And Past Environments, Ralf Vogelsang, Jurgen Richter, Zenobia Jacobs, Barbara Eichhorn, Veerle Linseele, Richard Roberts
Richard G Roberts
This paper presents new information obtained from a recent excavation and reassessment of the stratigraphy, chronology, archaeological assemblages and environmental context of the Apollo 11 rockshelter, which contains the longest late Pleistocene and Holocene archaeological sequence in Namibia. The Middle Stone Age (MSA) industries represented at the site include an early MSA, Still Bay, Howieson's Poort and late MSA. Optically stimulated luminescence (OSL) dating of individual quartz grains yielded numerical ages for the Still Bay and Howieson's Poort, and indicated the presence of a post-Howieson's Poort phase. OSL dating also verified conventional and accelerator mass spectrometry radiocarbon ages for a …
Single-Grain Osl Dating Of Glaciofluvial Quartz Constrains Reid Glaciation In Nw Canada To Mis 6, Martina Demuro, D Froese, Lee Arnold, Richard Roberts
Single-Grain Osl Dating Of Glaciofluvial Quartz Constrains Reid Glaciation In Nw Canada To Mis 6, Martina Demuro, D Froese, Lee Arnold, Richard Roberts
Richard G Roberts
Improved chronological control on the penultimate advance of the Cordilleran Ice Sheet in northwest Canada (the Reid glaciation) is required for a better understanding of late Quaternary palaeoclimatic and palaeoenvironmental change in eastern Beringia. However, reliable dating of glaciation events beyond the last glacial maximum is commonly hindered by a lack of directly dateable material. In this study we (i) provide the first combined minimum and maximum age constraint on the Reid glaciation at Ash Bend, its reference locale in the Stewart River valley, northwestern Canadian Cordillera, using single-grain optically stimulated luminescence dating of quartz; and (ii) compare the timing …
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Optical Dating Of Perennially Frozen Deposits Associated With Preserved Ancient Plant And Animal Dna In North-Central Siberia, Richard Roberts, Lee Arnold, F Brock, E Willerslev, A Tikhonov, R Macphee
Richard G Roberts
No abstract provided.
Ancient Dna Reveals Late Survival Of Mammoth And Horse In Interior Alaska, James Haile, D. Froese, R. Macphee, Richard Roberts, Lee Arnold, Alberto Reyes, Morten Rasmussen, Rasmus Nielsen, Barry Brook, Simon Robinson, Martina Demuro, M. Gilbert, Kasper Munch, Jeremy Austin, Alan Cooper, Ian Barnes, Per Moller, E. Willerslev
Ancient Dna Reveals Late Survival Of Mammoth And Horse In Interior Alaska, James Haile, D. Froese, R. Macphee, Richard Roberts, Lee Arnold, Alberto Reyes, Morten Rasmussen, Rasmus Nielsen, Barry Brook, Simon Robinson, Martina Demuro, M. Gilbert, Kasper Munch, Jeremy Austin, Alan Cooper, Ian Barnes, Per Moller, E. Willerslev
Richard G Roberts
No abstract provided.
Astronomically Calibrated 40ar/39ar Age For The Toba Supereruption And Global Synchronization Of Late Quaternary Records, Michael Storey, Richard Roberts, Mokhtar Saidin
Astronomically Calibrated 40ar/39ar Age For The Toba Supereruption And Global Synchronization Of Late Quaternary Records, Michael Storey, Richard Roberts, Mokhtar Saidin
Richard G Roberts
The Toba supereruption in Sumatra, ∼74 thousand years (ka) ago, was the largest terrestrial volcanic event of the Quaternary. Ash and sulfate aerosols were deposited in both hemispheres, forming a time-marker horizon that can be used to synchronize late Quaternary records globally. A precise numerical age for this event has proved elusive, with dating uncertainties larger than the millennial-scale climate cycles that characterized this period. We report an astronomically calibrated (40)Ar/(39)Ar age of 73.88 ± 0.32 ka (1σ, full external errors) for sanidine crystals extracted from Toba deposits in the Lenggong Valley, Malaysia, 350 km from the eruption source and …
Ages For The Middle Stone Age Of Southern Africa: Implications For Human Behavior And Dispersal, Zenobia Jacobs, Richard Roberts, Rex Galbraith, Hilary Deacon, Rainer Grun, Alex Mackay, Peter Mitchell, Ralf Vogelsang, Lyn Wadley
Ages For The Middle Stone Age Of Southern Africa: Implications For Human Behavior And Dispersal, Zenobia Jacobs, Richard Roberts, Rex Galbraith, Hilary Deacon, Rainer Grun, Alex Mackay, Peter Mitchell, Ralf Vogelsang, Lyn Wadley
Richard G Roberts
The expansion of modern human populations in Africa 80,000 to 60,000 years ago and their initial exodus out of Africa have been tentatively linked to two phases of technological and behavioral innovation within the Middle Stone Age of southern Africa—the Still Bay and Howieson's Poort industries—that are associated with early evidence for symbols and personal ornaments. Establishing the correct sequence of events, however, has been hampered by inadequate chronologies. We report ages for nine sites from varied climatic and ecological zones across southern Africa that show that both industries were short-lived (5000 years or less), separated by about 7000 years, …
A High-Resolution Record Of Vegetation And Climate Through The Last Glacial Cycle From Caledonia Fen, Southeastern Highlands Of Australia, A Kershaw, G Mckenzie, N Porch, Richard Roberts, J Browne, H Heijnis, M Orr, Geraldine Jacobsen, P Newall
A High-Resolution Record Of Vegetation And Climate Through The Last Glacial Cycle From Caledonia Fen, Southeastern Highlands Of Australia, A Kershaw, G Mckenzie, N Porch, Richard Roberts, J Browne, H Heijnis, M Orr, Geraldine Jacobsen, P Newall
Richard G Roberts
A blocked tributary has provided a rare site of long-term sediment accumulation in montane southeastern Australia. This site has yielded a continuous, detailed pollen record through the last ca. 140 000 years and revealed marked vegetation and environmental changes at orbital to sub-millennial scales. Radiocarbon and optically stimulated luminescence (OSL, or optical) ages provide some chronological control for the last ca. 70 000 years. Most of the sediment is inorganic but with well preserved pollen that accumulated under unproductive and probably largely ice-covered lake conditions. The lake was surrounded by low-growing plants with an alpine character. Exceptions include three discrete …
An Improved Osl Chronology For The Still Bay Layers At Blombos Cave, South Africa: Further Tests Of Single-Grain Dating Procedures And A Re-Evaluation Of The Timing Of The Still Bay Industry Across Southern Africa, Zenobia Jacobs, Elspeth Hayes, Richard Roberts, Rex Galbraith, Christopher Henshilwood
An Improved Osl Chronology For The Still Bay Layers At Blombos Cave, South Africa: Further Tests Of Single-Grain Dating Procedures And A Re-Evaluation Of The Timing Of The Still Bay Industry Across Southern Africa, Zenobia Jacobs, Elspeth Hayes, Richard Roberts, Rex Galbraith, Christopher Henshilwood
Richard G Roberts
This paper presents a series of new single-grain optically stimulated luminescence (OSL) ages for the Still Bay at Blombos Cave, South Africa, and compares them to previously published OSL, thermoluminescence (TL) and electron-spin resonance (ESR) ages for this site. Details are provided about the measurement and analytical procedures, including a discussion of the characteristics of the OSL signals of individual quartz grains. This forms the basis for further investigations into the sensitivity of the equivalent dose (De) estimates to a range of different analytical approaches, including changes in the size of the test dose, the choice of signal integration interval, …
Natural Variations In The Properties Of Tl And Irsl Emissions From Metamorphic And Volcanic K-Feldspars From East Africa: Assessing Their Reliability For Dating, L Gliganic, Richard Roberts, Z Jacobs
Natural Variations In The Properties Of Tl And Irsl Emissions From Metamorphic And Volcanic K-Feldspars From East Africa: Assessing Their Reliability For Dating, L Gliganic, Richard Roberts, Z Jacobs
Richard G Roberts
The elevated temperature infrared stimulated luminescence (IRSL) and post-IR IRSL signals of potassium (K)-feldspars have recently garnered attention for their minimal rates of anomalous fading. The post-IR IRSL signal has been used to obtain age estimates for geological deposits, mostly in Europe. Studies on the behaviour of the IRSL and post-IR IRSL signals of K-feldspars from a wider range of geographic regions and depositional contexts are needed, particularly for regions where the OSL signal from quartz is poorly behaved. Discrepancies in the literature regarding the behaviours of the IRSL and TL signals of K-feldspars also highlight the need to characterise …
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Initial Speleothem Results From Western Flores And Eastern Java, Indonesia: Were Climate Changes From 47 To 5ka Responsible For The Extinction Of Homo Floresiensis?, Richard Roberts, Allan Chivas, T. Sutikna, Michael Morwood, J Zhao, Kira Westaway
Richard G Roberts
No abstract provided.
Redating The Advance Of The New Zealand Franz Josef Glacier During The Last Termination: Evidence For Asynchronous Climate Change, Richard Roberts, Christian Turney, Matt Mcglone, J Cooper, J Wilmshurst, N De Jonge, C Prior
Redating The Advance Of The New Zealand Franz Josef Glacier During The Last Termination: Evidence For Asynchronous Climate Change, Richard Roberts, Christian Turney, Matt Mcglone, J Cooper, J Wilmshurst, N De Jonge, C Prior
Richard G Roberts
No abstract provided.
New Ages For Middle And Later Stone Age Deposits At Mumba Rockshelter, Tanzania: Optically Stimulated Luminescence Dating Of Quartz And Feldspar Grains, Luke Gliganic, Zenobia Jacobs, Richard Roberts, M Dominguez-Rodrigo, A Mabulla
New Ages For Middle And Later Stone Age Deposits At Mumba Rockshelter, Tanzania: Optically Stimulated Luminescence Dating Of Quartz And Feldspar Grains, Luke Gliganic, Zenobia Jacobs, Richard Roberts, M Dominguez-Rodrigo, A Mabulla
Richard G Roberts
The archaeological deposits at Mumba rockshelter, northern Tanzania, have been excavated for more than 70 years, starting with Margit and Ludwig Köhl-Larsen in the 1930s. The assemblages of Middle Stone Age (MSA) and Later Stone Age (LSA) artefacts collected from this site constitute the type sequences for these cultural phases in East Africa. Despite its archaeological importance, however, the chronology of the site is poorly constrained, despite the application since the 1980s of several dating methods (radiocarbon, uranium-series and amino acid racemisation) to a variety of materials recovered from the deposits. Here, we review these previous chronologies for Mumba and …
Human Occupation, Adaptation And Behavioural Change In The Pleistocene And Holocene Of South India: Recent Investigations In The Kurnool District, Andhra Pradesh, Richard Roberts, Kevin White, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Clive Oppenheimer, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Janardhana B, Jamie Hampson, Preston Miracle, Kevin Cunningham, M Kasturi Bai, Dorian Fuller, Michael Haslam
Human Occupation, Adaptation And Behavioural Change In The Pleistocene And Holocene Of South India: Recent Investigations In The Kurnool District, Andhra Pradesh, Richard Roberts, Kevin White, Christopher Clarkson, Jinu Koshy, Ravi Korisettar, Sacha Jones, Clive Oppenheimer, Nicole Boivin, Michael Petraglia, Peter Ditchfield, Janardhana B, Jamie Hampson, Preston Miracle, Kevin Cunningham, M Kasturi Bai, Dorian Fuller, Michael Haslam
Richard G Roberts
No abstract provided.
Establishing The Time Of Initial Human Occupation Of Liang Bua, Western Flores, Indonesia, Kira Westaway, Michael Morwood, Richard Roberts, J Zhao, T. Sutikna, E.W. Saptomo, W Rink
Establishing The Time Of Initial Human Occupation Of Liang Bua, Western Flores, Indonesia, Kira Westaway, Michael Morwood, Richard Roberts, J Zhao, T. Sutikna, E.W. Saptomo, W Rink
Richard G Roberts
No abstract provided.
Reconstructing The Geomorphic History Of Liang Bua, Flores, Indonesia: A Stratigraphic Interpretation Of The Occupational Environment, Kira Westaway, T. Sutikna, W. Saptomo, _ Jatmiko, M Morwood, Richard Roberts, D. Hobbs
Reconstructing The Geomorphic History Of Liang Bua, Flores, Indonesia: A Stratigraphic Interpretation Of The Occupational Environment, Kira Westaway, T. Sutikna, W. Saptomo, _ Jatmiko, M Morwood, Richard Roberts, D. Hobbs
Richard G Roberts
No abstract provided.
Low Temperature (Lt) Combustion Of Sediments Does Not Necessarily Provide Accurate Radiocarbon Ages For Site Chronology, F. Brock, D. Froese, Richard Roberts
Low Temperature (Lt) Combustion Of Sediments Does Not Necessarily Provide Accurate Radiocarbon Ages For Site Chronology, F. Brock, D. Froese, Richard Roberts
Richard G Roberts
No abstract provided.
Age Constraints On Pleistocene Megafauna At Tight Entrance Cave In Southwestern Australia, Richard Roberts, L K Fifield, R. Grun, Richard Jones, M Bird, Gavin Prideaux, G Gully, Linda Ayliffe, Richard Cresswell
Age Constraints On Pleistocene Megafauna At Tight Entrance Cave In Southwestern Australia, Richard Roberts, L K Fifield, R. Grun, Richard Jones, M Bird, Gavin Prideaux, G Gully, Linda Ayliffe, Richard Cresswell
Richard G Roberts
No abstract provided.