Christopher Bronk Ramsey
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View article: Nondegenerate actions on Hilbert C*-modules
Nondegenerate actions on Hilbert C*-modules Open
Let X be a (right) Hilbert C*-module and let B be a C*-algebra acting on X from the left via adjointable operators. In this note we establish the equivalence of two notions of nondegeneracy for such an action of B on X. Furthermore, we exp…
View article: Couniversality for C*-algebras of residually finite-dimensional operator algebras
Couniversality for C*-algebras of residually finite-dimensional operator algebras Open
The C*-envelope of a non self-adjoint operator algebra is known to encode many properties of the underlying subalgebra. However, the C*-envelope does not always encode the residual finite-dimensionality of an operator algebra. To elucidate…
View article: Crossed products and $\mathrm{C}^{*}$-covers of semi-Dirichlet operator algebras
Crossed products and $\mathrm{C}^{*}$-covers of semi-Dirichlet operator algebras Open
In this paper, we show that the semi-Dirichlet \mathrm{C}^{*} -covers of a semi-Dirichlet operator algebra form a complete lattice, establishing that there is a maximal semi-Dirichlet \mathrm{C}^{*} -cover. Given an operator algebra dynami…
View article: Localised land-use and maize agriculture by the pre-Columbian Casarabe Culture in Lowland Bolivia
Localised land-use and maize agriculture by the pre-Columbian Casarabe Culture in Lowland Bolivia Open
Multiple pre-Columbian (pre-1492 CE) archaeological sites now challenge the traditional portrayal of Amazonia as a ‘pristine wilderness’. This is especially true within the forest-savanna mosaic landscapes of lowland Bolivia, where the pre…
View article: A 350 <sup>14</sup> C yr discrepancy between bone and tooth dates from the same grave at the Early Neolithic cemetery of Shamanka II, Lake Baikal, southern Siberia: reservoir effects or a misplaced mandible?
A 350 <sup>14</sup> C yr discrepancy between bone and tooth dates from the same grave at the Early Neolithic cemetery of Shamanka II, Lake Baikal, southern Siberia: reservoir effects or a misplaced mandible? Open
A 350 14 C yr discrepancy was found between dates on postcranial remains and mandibular teeth on what was thought to be the same individual from the Early Neolithic cemetery of Shamanka II, Lake Baikal. Stable nitrogen isotope results sugg…
View article: Relative position in binary substitutions
Relative position in binary substitutions Open
Given an infinite word ${\bf w}$ on a finite alphabet, an immediate question arises:~can we understand the frequency of letters in ${\bf w}$\,? For words that are the fixed points of substitutions, the answer to this question is often `yes…
View article: Diffraction of the primes and other sets of zero density
Diffraction of the primes and other sets of zero density Open
In this paper, we show that the diffraction of the primes is absolutely continuous, showing no bright spots (Bragg peaks). We introduce the notion of counting diffraction, extending the classical notion of (density) diffraction to sets of …
View article: Biodiversity responses to Lateglacial climate change in the subdecadally-resolved record of Lake Hämelsee (Germany)
Biodiversity responses to Lateglacial climate change in the subdecadally-resolved record of Lake Hämelsee (Germany) Open
Anthropogenically-driven climate warming and land use change are the main causes of an ongoing decrease in global biodiversity. It is unclear how ecosystems, particularly freshwater habitats, will respond to such continuous and potentially…
View article: At an important tephrostratigraphic crossroads: cryptotephra in Late Glacial to Early Holocene lake sediments from the Carpathian Mountains, Romania
At an important tephrostratigraphic crossroads: cryptotephra in Late Glacial to Early Holocene lake sediments from the Carpathian Mountains, Romania Open
Understanding the temporal and spatial environmental response to past climate change during the Last Glacial-Interglacial Transition (LGIT, 16-8 ka) across Europe relies on precise chronologies for palaeoenvironmental records. Tephra layer…
View article: China’s Increasing Influence: What This Means for American Security
China’s Increasing Influence: What This Means for American Security Open
Purpose: With its growing domestic and international interest, China has solidified itself as a significant player in international relations, shaking up traditional geopolitics through its military and economic expansion and shifting focu…
View article: On numerical diameters and linear maps
On numerical diameters and linear maps Open
This paper studies the diameter of the numerical range of bounded operators on Hilbert space and the induced seminorm, called the numerical diameter, on bounded linear maps between operator systems which is sensible in the case of unital m…
View article: Resilience, innovation and collapse of settlement networks in later Bronze Age Europe: New survey data from the southern Carpathian Basin
Resilience, innovation and collapse of settlement networks in later Bronze Age Europe: New survey data from the southern Carpathian Basin Open
Societies of the later Early to Middle Bronze Age (ca. 2200–1600 BC) in the Carpathian Basin exhibited complex, hierarchical and regionally influential socio-political organisation that came to an abrupt end in the 16 th century BC. Consid…
View article: A Scan of Pleiotropic Immune Mediated Disease Genes Identifies Novel Determinants of Baseline FVIII Inhibitor Status in Hemophilia-A
A Scan of Pleiotropic Immune Mediated Disease Genes Identifies Novel Determinants of Baseline FVIII Inhibitor Status in Hemophilia-A Open
Hemophilia-A (HA) is caused by heterogeneous loss-of-function factor (F)VIII gene ( F8 )-mutations and deficiencies in plasma-FVIII-activity that impair intrinsic-pathway-mediated coagulation-amplification. The standard-of-care for severe-…
View article: Generating functions of substitutions
Generating functions of substitutions Open
We prove that a substitution is aperiodic if and only if some of its associated generating functions are transcendental. These generating functions have a recursive structure arising from the substitution which we use to study their roots …
View article: Crossed products and C*-covers of semi-Dirichlet operator algebras
Crossed products and C*-covers of semi-Dirichlet operator algebras Open
In this paper, we show that the semi-Dirichlet C*-covers of a semi-Dirichlet operator algebra form a complete lattice, establishing that there is a maximal semi-Dirichlet C*-cover. Given an operator algebra dynamical system we prove a dila…
View article: MARINE RADIOCARBON CALIBRATION IN POLAR REGIONS: A SIMPLE APPROXIMATE APPROACH USING MARINE20
MARINE RADIOCARBON CALIBRATION IN POLAR REGIONS: A SIMPLE APPROXIMATE APPROACH USING MARINE20 Open
The Marine20 radiocarbon ( 14 C) age calibration curve, and all earlier marine 14 C calibration curves from the IntCal group, must be used extremely cautiously for the calibration of marine 14 C samples from polar regions (outside ∼ 40ºS–4…
View article: DEVELOPMENT OF THE INTCAL DATABASE
DEVELOPMENT OF THE INTCAL DATABASE Open
The IntCal family of radiocarbon ( 14 C) calibration curves is based on research spanning more than three decades. The IntCal group have collated the 14 C and calendar age data (mostly derived from primary publications with other types of …
View article: RADIOCARBON CALIBRATION: FROM BANE TO BLESSING
RADIOCARBON CALIBRATION: FROM BANE TO BLESSING Open
Temporal and spatial variation in radiocarbon ( 14 C) in the atmosphere has been the subject of investigation from the first pioneering work of Libby and Arnold. However, as the precision of measurements has improved, now by almost two ord…
View article: Feeding Anglo-Saxon England: a bioarchaeological dataset for the study of early medieval agriculture (Data paper)
Feeding Anglo-Saxon England: a bioarchaeological dataset for the study of early medieval agriculture (Data paper) Open
The FeedSax project combined bioarchaeological data with evidence from settlement archaeology to investigate how, when and why the expansion of arable farming occurred between the 8th-13th centuries in England. It has generated and release…
View article: The Lattice of C*-covers of an operator algebra
The Lattice of C*-covers of an operator algebra Open
In this paper it is shown that the lattice of C*-covers of an operator algebra does not contain enough information to distinguish operator algebras up to completely isometric isomorphism. In addition, four natural equivalences of the latti…
View article: Pleistocene climatic variability in eastern Africa influenced hominin evolution: the 620,000-year climate record from Chew Bahir
Pleistocene climatic variability in eastern Africa influenced hominin evolution: the 620,000-year climate record from Chew Bahir Open
As a contribution towards a regional environmental context of human-climate interactions, the ICDP co-funded Chew Bahir Drilling Project, a part of the HSPDP (Hominin Sites and Paleolakes Drilling Project), recovered ~280-m long cores of s…
View article: Neolithic and Early Bronze Age of Cis-Baikal: Spatiotemporal Patterns of Cemetery Use
Neolithic and Early Bronze Age of Cis-Baikal: Spatiotemporal Patterns of Cemetery Use Open
Hunter-gatherer archaeology typically focusses on the details of subsistence strategies and material culture and, in the case of cemeteries, on various aspects of mortuary practices, beliefs, and social differentiation. This paper aims to …