Virtual Reconstruction and Morphological Analysis of the Cranium of an Ancient Egyptian Mummy

A mummy of an Egyptian priestess dating from the 22nd dynasty (c. 770 BC), completely enclosed in an anthropoid (human shaped) coffin, was scanned on a CT scanner. An accurate reconstruction of the cranium was generated from 115 × 2 mm CT images using AVS/Express on a SGI computer. Linear measurements were obtained from six orthogonal cranial views and used in a morphometric analysis software package (CRANID). The analyses carried out were both linear and nearest neighbour discriminant analysis. The results show that there is a 52.9% probability that the mummy is an Egyptian female, with a 24.5% probability that mummy is an African female. Thus the technique confirms that the coffin contains an Egyptian female, which is consistent with the inscription on the coffin and the shape of the pelvic bones as revealed by plain X-rays. These results show that this technique has potential for analysing forensic cases where the bones are obscured by soft tissue and clothing. This technique may have an application in virtual autopsies

High resolution photoemission study of SiOx/Si(111) interface disruption following in situ HfO₂deposition

We report on an in situ high resolution core level photoemission study of the early stages of interface formation between an ultrathin SiOx layer ( ∼ 0.3 nm) grown on the atomically clean Si(111) surface and a HfO2 dielectric layer. Si 2p core level spectra acquired at 130 eV photon energy reveal evidence of a chemically shifted component on the lower binding energy side of the substrate peak which is attributed to interface defect states resulting from the incorporation of silicon atoms from the substrate into the interfacial oxide at room temperature. This evidence of Si/SiOx interface disruption would be expected to increase charge carrier scattering mechanisms in the silicon and contribute to the generally observed mobility degradation in high-k stacks with ultrathin silicon oxide interface layers

Infection-acquired versus vaccine-acquired immunity in an SIRWS model

Despite high vaccine coverage, pertussis has re-emerged as a public health concern in many countries. One hypothesis posed for re-emergence is the waning of immunity. In some disease systems, the process of waning immunity can be non-linear, involving a complex relationship between the duration of immunity and subsequent boosting of immunity through asymptomatic re-exposure. We present and analyse a model of infectious disease transmission to examine the interplay between infection and immunity. By allowing the duration of infection-acquired immunity to differ from that of vaccine-acquired immunity, we explore the impact of the difference in durations on long-term disease patterns and prevalence of infection. Our model demonstrates that vaccination may induce cyclic behaviour, and its ability to reduce the infection prevalence increases with both the duration of infection-acquired immunity and duration of vaccine-acquired immunity. We find that increasing vaccine coverage, while capable of leading to an increase in overall transmission, always results in a reduction in prevalence of primary infections, with epidemic cycles characterised by a longer interepidemic period and taller peaks. Our results show that the epidemiological patterns of an infectious disease may change considerably when the duration of vaccine-acquired immunity differs from that of infection-acquired immunity. Our study highlights that for any particular disease and associated vaccine, a detailed understanding of the duration of protection and how that duration is influenced by infection prevalence is important as we seek to optimise vaccination strategies.Comment: 21 pages, 5 figure

Early Miocene Cape Blanco Flora of Oregon

Deposition of the shallow marine sandstone of Floras Lake was interrupted by a transient deltaic progradation of redeposited volcanic tuff, which contains the Cape Blanco flora.  Dating by 40Ar/39Ar on fresh plagioclase constrains the age of the plant-bearing tuff to 18.24 ± 0.86 Ma, because we interpret this age of eruption and landscape loading with ash, as within only a few years of redeposition.  Several plausible sources of the tuff can be identified from caldera eruptions in the Cascade Volcanic Arc.  The relation between the early Miocene Cascade volcanic arc and the Klamath Terrane has been fixed since the early Miocene, and the high Cr2O3 in the sandstones is an indication that the source area for the sandstone of Floras Lake was the Klamath Terrane.  Fossil leaves and other plant organs of 33 species of the Cape Blanco flora represent floral diversity and paleoclimate of coastal Oregon during the early Miocene. The flora includes a variety of thermophilic elements from California, including coast redwood (Sequoia affinis), and avocado (Persea pseudocarolinensis), and is numerically dominated by live oak (Quercus hannibalii), and chinquapin (Chrysolepis sonomensis). The size and proportion of serrate margins of the fossil leaves are evidence of mean annual temperature of ~14 º C and a mean annual precipitation of ~223 cm/yr for the Cape Blanco flora.  Comparison of the Cape Blanco flora with the Temblor flora of California and the Seldovia flora of Alaska reveals a latitudinal gradient of ~ 0.6 º C/degree latitude, compared with a gradient of ~0.3 º C/degree latitude from isotopic composition of marine foraminifera of the northeast Pacific Ocean.  Both results confirm that the late early Miocene mean annual temperature at 45º north latitude was 4-5 º C warmer than today