Radiocarbon dating and the Naqada relative chronology

The Naqada relative chronology provides the main cultural framework for the Predynastic period of ancient Egypt. It was devised in the late nineteenth century by Flinders Petrie to improve understanding of the prehistoric origins of the Egyptian state. Petrie's approach became widely known and formed the basis for the development of seriation. In this study, we test the reliability of the Naqada relative chronology as a dating tool against all the relevant radiocarbon information. The results show that the main blocks of the relative sequence do form a true chronology, but also indicate that the system is much less reliable at the level of individual phases. We discuss the nature of the discrepancies and the broader influence of the relative chronology on current understanding of Early Egypt

A putative relay circuit providing low-threshold mechanoreceptive input to lamina I projection neurons via vertical cells in lamina II of the rat dorsal horn

Background: Lamina I projection neurons respond to painful stimuli, and some are also activated by touch or hair movement. Neuropathic pain resulting from peripheral nerve damage is often associated with tactile allodynia (touch-evoked pain), and this may result from increased responsiveness of lamina I projection neurons to non-noxious mechanical stimuli. It is thought that polysynaptic pathways involving excitatory interneurons can transmit tactile inputs to lamina I projection neurons, but that these are normally suppressed by inhibitory interneurons. Vertical cells in lamina II provide a potential route through which tactile stimuli can activate lamina I projection neurons, since their dendrites extend into the region where tactile afferents terminate, while their axons can innervate the projection cells. The aim of this study was to determine whether vertical cell dendrites were contacted by the central terminals of low-threshold mechanoreceptive primary afferents. Results: We initially demonstrated contacts between dendritic spines of vertical cells that had been recorded in spinal cord slices and axonal boutons containing the vesicular glutamate transporter 1 (VGLUT1), which is expressed by myelinated low-threshold mechanoreceptive afferents. To confirm that the VGLUT1 boutons included primary afferents, we then examined vertical cells recorded in rats that had received injections of cholera toxin B subunit (CTb) into the sciatic nerve. We found that over half of the VGLUT1 boutons contacting the vertical cells were CTb-immunoreactive, indicating that they were of primary afferent origin. Conclusions: These results show that vertical cell dendritic spines are frequently contacted by the central terminals of myelinated low-threshold mechanoreceptive afferents. Since dendritic spines are associated with excitatory synapses, it is likely that most of these contacts were synaptic. Vertical cells in lamina II are therefore a potential route through which tactile afferents can activate lamina I projection neurons, and this pathway could play a role in tactile allodynia

Neuronal circuitry for pain processing in the dorsal horn

Neurons in the spinal dorsal horn process sensory information, which is then transmitted to several brain regions, including those responsible for pain perception. The dorsal horn provides numerous potential targets for the development of novel analgesics and is thought to undergo changes that contribute to the exaggerated pain felt after nerve injury and inflammation. Despite its obvious importance, we still know little about the neuronal circuits that process sensory information, mainly because of the heterogeneity of the various neuronal components that make up these circuits. Recent studies have begun to shed light on the neuronal organization and circuitry of this complex region

Critical assessment of the elemental composition of Corning archeological reference glasses by LA-ICP-MS

Corning archeological reference glasses A, B, C, and D have been made to simulate different historic technologies of glass production and are used as standards in historic glass investigations. In this work, nanoseconds (193, 266 nm) and femtosecond (800 nm) laser ablation were used to study the elemental composition of Corning glasses using laser ablation inductively coupled plasma mass spectrometry. The determined concentrations of 26 oxides (Li2O, B2O3, Na2O, MgO, Al2O3, SiO2, P2O5, K2O, CaO, TiO2, V2O5, Cr2O3, MnO, Fe2O3, CoO, NiO, CuO, ZnO, Rb2O, SrO, ZrO2, SnO2, Sb2O5, BaO, PbO, Bi2O3) are compared with values reported in the literature. Results show variable discrepancies between the data, with the largest differences found for Cr2O3 in Corning A; Li2O, B2O3, and Cr2O3 in Corning B; and MnO, Sb2O5, Cr2O3, and Bi2O3 in Corning C. The best agreement between the measured and literature values was found for Corning D. However, even for this reference, glass re-evaluation of the data was necessary and new values for PbO, BaO, and Bi2O3 are proposed

Effects of peripheral nerve injury on parvalbumin expression in adult rat dorsal root ganglion neurons

Background: Parvalbumin (PV) is a calcium binding protein that identifies a subpopulation of proprioceptive dorsal root ganglion (DRG) neurons. Calcitonin gene-related peptide (CGRP) is also expressed in a high proportion of muscle afferents but its relationship to PV is unclear. Little is known of the phenotypic responses of muscle afferents to nerve injury. Sciatic nerve axotomy or L5 spinal nerve ligation and section (SNL) lesions were used to explore these issues in adult rats using immunocytochemistry. Results: In naive animals, the mean PV expression was 25 % of L4 or L5 dorsal root ganglion (DRG) neurons, and this was unchanged 2 weeks after sciatic nerve axotomy. Colocalization studies with the injury marker activating transcription factor 3 (ATF3) showed that approximately 24 % of PV neurons expressed ATF3 after sciatic nerve axotomy suggesting that PV may show a phenotypic switch from injured to uninjured neurons. This possibility was further assessed using the spinal nerve ligation (SNL) injury model where injured and uninjured neurons are located in different DRGs. Two weeks after L5 SNL there was no change in total PV staining and essentially all L5 PV neurons expressed ATF3. Additionally, there was no increase in PV-ir in the adjacent uninjured L4 DRG cells. Co-labelling of DRG neurons revealed that less than 2 % of PV neurons normally expressed CGRP and no colocalization was seen after injury. Conclusion: These experiments clearly show that axotomy does not produce down regulation of PV protein in the DRG. Moreover, this lack of change is not due to a phenotypic switch in PV immunoreactive (ir) neurons, or de novo expression of PV-ir in uninjured neurons after nerve injury. These results further illustrate differences that occur when muscle afferents are injured as compared to cutaneous afferents

New data on the soda flux used in the production of Iznik glazes and Byzantine glasses

© 2016 University of Oxford. Previous research has shown that Iznik glazes are characterized by low potash and magnesia contents. It was therefore suggested that the flux used was either a purified plant ash or some unidentified mineral source of soda. More recently, as a result of the detection of small, but significant, amounts of boron and lithium in Byzantine glasses from western Turkey, which also exhibit low potash and magnesia contents, it has been suggested that the source of the flux used was a soda-rich evaporite associated in some way with the extensive borax deposits in the region. LA-ICP-MS has been used to establish that Iznik glazes also contain similarly small amounts of boron and lithium. The Na/K, Na/Mg, Na/Ca and Na/B ratios for these Iznik glazes are shown to be comparable to the equivalent ratios calculated from published data for waters from a range of Na-HCO 3 type hot springs in western Turkey, with the closest match being to the hot springs around Afyon-Gazligöl, which is consistent with documentary evidence. It is therefore proposed that the soda-rich salts produced by evaporating water from these springs to dryness would have provided the flux required for the production of Iznik glazes and high-boron Byzantine glasses.status: publishe

Radiocarbon verification of the earliest astro-chronological datum

Papyri 10012A and 10012B from Illahun, Egypt, provide the earliest astro-chronological datum in history and, while calculated to various years in the 19th century BCE, have never been independently verified. As this datum enables the Middle Kingdom (MK) section of Egyptian historical chronology to be anchored in absolute time, it establishes the principal calendrical timeline for the eastern Mediterranean Bronze Age in the first half of the 2nd millennium BCE. AMS radiocarbon measurements of Papyrus 10012B establish its date range to 1886-1750 BCE, confirming the astronomical calculations and the essential reliability of Egyptian historical chronology for this period. Furthermore, all three leading estimates for the calendar year attribution of the document are supported by this analysis, with the role of a possible growing season effect determining which is most favored

Radiocarbon verification of the earliest astro-chronological datum

Papyri 10012A and 10012B from Illahun, Egypt, provide the earliest astro-chronological datum in history and, while calculated to various years in the 19th century BCE, have never been independently verified. As this datum enables the Middle Kingdom (MK) section of Egyptian historical chronology to be anchored in absolute time, it establishes the principal calendrical timeline for the eastern Mediterranean Bronze Age in the first half of the 2nd millennium BCE. AMS radiocarbon measurements of Papyrus 10012B establish its date range to 1886-1750 BCE, confirming the astronomical calculations and the essential reliability of Egyptian historical chronology for this period. Furthermore, all three leading estimates for the calendar year attribution of the document are supported by this analysis, with the role of a possible growing season effect determining which is most favored

The Analysis of Late Bronze Age Glass from Nuzi and the Question of the Origin of Glass-Making

© 2017 University of Oxford This paper re-analyses a considerable corpus of glass from the Late Bronze Age site of Nuzi, found near Kirkuk in Iraq. SEM–WDS and Sr and Nd isotopic analysis were applied, in addition to cataloguing the glass. The work showed that the glass technology at Nuzi was subtly different from contemporary Egyptian sites, using different ways of opacifying and working glass. At least two, perhaps three, Near Eastern production sites are postulated. The range of glass colours and the skill of their application at Nuzi was perhaps not on a par with the Egyptian sites. This led to a reconsideration and review of the accepted wisdom that the Near East is the source of the innovation that is glass-making. This opinion is based on limited textual and iconographic sources and is dominated by an erroneous early date for a very developed Nuzi glass industry along with a few finds of glass vessels in early contexts. Some of this evidence has now been at least questioned, suggesting that glass-making in Egypt, at least as early as the middle of the 15th century bc, and probably earlier, is no later than that in the Near East. It is argued that it is far from clear that the Near East was the source of the innovation and that a more cautious approach would better fit the evidence.status: publishe