Taphonomic approaches to distinguish chewing damage from knapping marks in Palaeolithic faunal assemblages

The imprint of human actions on mammal remains from archaeological sites is often fragmented and attenuated due to post-mortem processes, which add to the challenge of distinguishing human from natural modifications in faunal assemblages. Identifying minimally-worked bone tools poses a particular challenge when they are mixed with bones that have been modified by other agents. Bones, antlers and teeth used as hammers or pressure-flakers in flint-knapping can be particularly difficult to identify because knapping damage resembles carnivore chewing marks. This paper presents a methodological approach to establish diagnostic criteria for identifying whether bones from archaeological sites were modified by chewing or knapping, using observations at macroscopic and microscopic levels. We applied these criteria to case studies from the Upper Palaeolithic (Magdalenian) site of Gough's Cave (UK). Analysis of Magdalenian stone tools shows that blades were detached with a soft hammer, yet organic (soft) knapping tools appear to be scarce in Magdalenian contexts. We propose that the difficulty in identifying knapping damage on bones that have undergone only a short period of use, combined with the macroscopic similarity of these marks with natural modifications (e.g., carnivore chewing), are significant factors contributing to the rarity of minimally-modified knapping tools in archaeological contexts

The Role of Cadherins and Catenins in the Segregation and Migration of Spinal Motor Neurons

During development Spinal motor neurons are generated from their point of origin in the ventricular zone and migrate to reach their final settling position (motor pools) in the ventral spinal cord. The formation of motor pools depends on early motor column segregation; cadherins cell adhesive proteins have been implicated in the segregation of motor neurons in the spinal cord but the exact role for these cell-cell adhesion molecules in the organisation and migration of spinal motor neurons during development is not established. I show that during development expression of cadherins contribute to the organisation and migration of spinal lateral motor column (LMC) motor neurons to their final settling positions and there is close association between spinal motor neuron and radial glia. Misexpression of a dominant negative cadherin results in abnormal migration of spinal motor neurons and columnar desegregation. Similarly, expression of a dominant negative catenin (a major cytoplasmic binding partner to cadherins) results in columnar desegregation and arrest of motor neuron along their migratory route. Perturbations of Wnt signalling have no effect on motor neurons migration indicating that the results are due to perturbation of cadherin adhesive function. Our observation that cadherin and catenins but not Wnt signalling contributes to normal migration and segregation of spinal motor neurons, suggest that cadherin may act in close association with radial glia in directing the migration of spinal motor neurons similar to the establish role of radial glia in cortical neuronal migration

Cephalometric Assessment of the Fourth Ventricles Using Computerized Tomography: A Five Year Study in Usmanu Danfodiyo University Teaching Hospital (UDUTH), Sokoto, North-Western Nigeria

The fourth ventricle is usually affected in posterior cranial fossa tumours and other intracranial and ventricular disorders. Therefore, accurate measurement of the fourth ventricle will go a long way in evaluating braindisorders and decision making prior to neurosurgical procedures. This, therefore, places high premium on the accuracy in the technique and equipment used in obtaining a good Computerised Tomography (CT) Scan of the brain. To provide baseline data for measurements of normal fourth ventricle using computed tomographic Scan. Measurement was made with Dragon V3.1.1. A total of 652 scan examinations of subjects were analyzed in this study. 434 (65.79%) of the subjects were males while 217 (34.21%) were females. (M: F ratio = 2:1).The mean length of the fourth ventricles was 9.55mm and mean width was 12.86mm. Maximum length was 13.95mm and minimum length was 5.1mm. Least width was 2.65mm and greatest width was 17.28mm. Thus, the difference between the lengths of the fourth ventricles was not statistically significant (p.0.05), so also there was no statistically significant difference (p> 0.05) between the width of the fourth ventricles in males and females. In conclusion, this study has provided reference ranges for the normal values of the length and width of the fourth ventricle in male and female Nigerians.Keywords: Cephalometry, assessment, fourth ventricles, CT, Nigeria

Knapping tools in Magdalenian contexts: New evidence from Gough’s Cave (Somerset, UK)

Our knowledge of the recolonization of north-west Europe at the end of the Last Glacial Maximum depends to a large extent on finds from Gough's Cave (Somerset, UK). Ultra-high resolution radiocarbon determinations suggest that the cave was occupied seasonally by Magdalenian hunters for perhaps no more than two or three human generations, centred on 12,600 BP (~14,950-14,750 cal BP). They left behind a rich and diverse assemblage of Magdalenian lithic and osseous artefacts, butchered animal bones, and cannibalised human remains. The faunal assemblage from Gough's Cave is one of the most comprehensively studied from any Magdalenian site, yet new and unexpected discoveries continue to be made. Here, we record previously unrecognized flint-knapping tools that were identified during a survey of the Gough's Cave faunal collection at the Natural History Museum (London). We identified bones used as hammers and teeth manipulated as pressure-flakers to manufacture flint tools. Most of the pieces appear to be ad hoc (single-use?) tools, but a horse molar was almost certainly a curated object that was used over an extended period to work many stone tools. This paper explores how these knapping tools were used to support a more nuanced understanding of Magdalenian stone-tool manufacturing processes. Moreover, we provide a standard for identifying minimally-used knapping tools that will help to establish whether retouchers and other organic stone-working tools are as rare in the Magdalenian archaeological record as current studies suggest

Catenin-dependent cadherin function drives divisional segregation of spinal motor neurons

Motor neurons that control limb movements are organized as a neuronal nucleus in the developing ventral horn of the spinal cord called the lateral motor column. Neuronal migration segregates motor neurons into distinct lateral and medial divisions within the lateral motor column that project axons to dorsal or ventral limb targets, respectively. This migratory phase is followed by an aggregation phase whereby motor neurons within a division that project to the same muscle cluster together. These later phases of motor neuron organization depend on limb-regulated differential cadherin expression within motor neurons. Initially, all motor neurons display the same cadherin expression profile, which coincides with the migratory phase of motor neuron segregation. Here, we show that this early, pan-motor neuron cadherin function drives the divisional segregation of spinal motor neurons in the chicken embryo by controlling motor neuron migration. We manipulated pan-motor neuron cadherin function through dissociation of cadherin binding to their intracellular partners. We found that of the major intracellular transducers of cadherin signaling, γ-catenin and α-catenin predominate in the lateral motor column. In vivo manipulations that uncouple cadherin-catenin binding disrupt divisional segregation via deficits in motor neuron migration. Additionally, reduction of the expression of cadherin-7, a cadherin predominantly expressed in motor neurons only during their migration, also perturbs divisional segregation. Our results show that γ-catenin-dependent cadherin function is required for spinal motor neuron migration and divisional segregation and suggest a prolonged role for cadherin expression in all phases of motor neuron organization

Archaeological collections from Long Hole (Gower, Swansea, UK) and their place in the British Palaeolithic

At the time of its excavation in 1861, the cave site of Long Hole (Gower peninsula, Swansea, UK) was recognized as important for establishing the antiquity of man in Wales. However, in comparison to its more illustrious neighbour Paviland Cave, it has received very little attention since. Long Hole has been host to three documented excavations: by Colonel Wood in the 1860s, by John Campbell in 1969 and most recently the small-scale work in 2012 described in this paper. Here we outline Long Hole’s excavations and the archaeological material from the cave. Although the site’s earliest collections suffer from the familiar problems of being significantly selected and lacking contextual information, several conclusions are possible. Previous suggestions of two late Neanderthal occupations are unconvincing. Lithic artefacts from Long Hole are instead reminiscent of Aurignacian material from Paviland Cave, suggesting that they were left by some of Britain’s very early modern human occupants, 37–35,000 cal BP. Because Campbell excavated an apparently well-stratified Late Pleistocene sequence his collections have the greatest potential for future work

Magnetic Coupling in the Quiet Solar Atmosphere

Three kinds of magnetic couplings in the quiet solar atmosphere are highlighted and discussed, all fundamentally connected to the Lorentz force. First the coupling of the convecting and overshooting fluid in the surface layers of the Sun with the magnetic field. Here, the plasma motion provides the dominant force, which shapes the magnetic field and drives the surface dynamo. Progress in the understanding of the horizontal magnetic field is summarized and discussed. Second, the coupling between acoustic waves and the magnetic field, in particular the phenomenon of wave conversion and wave refraction. It is described how measurements of wave travel times in the atmosphere can provide information about the topography of the wave conversion zone, i.e., the surface of equal Alfv\'en and sound speed. In quiet regions, this surface separates a highly dynamic magnetic field with fast moving magnetosonic waves and shocks around and above it from the more slowly evolving field of high-beta plasma below it. Third, the magnetic field also couples to the radiation field, which leads to radiative flux channeling and increased anisotropy in the radiation field. It is shown how faculae can be understood in terms of this effect. The article starts with an introduction to the magnetic field of the quiet Sun in the light of new results from the Hinode space observatory and with a brief survey of measurements of the turbulent magnetic field with the help of the Hanle effect.Comment: To appear in "Magnetic Coupling between the Interior and the Atmosphere of the Sun", eds. S.S. Hasan and R.J. Rutten, Astrophysics and Space Science Proceedings, Springer-Verlag, Heidelberg, Berlin, 200

90,000 year-old specialised bone technology in the Aterian Middle Stone Age of North Africa

The question of cognitive complexity in early Homo sapiens in North Africa is intimately tied to the emergence of the Aterian culture (~145 ka). One of the diagnostic indicators of cognitive complexity is the presence of specialised bone tools, however significant uncertainty remains over the manufacture and use of these artefacts within the Aterian techno-complex. In this paper we report on a bone artefact from Aterian Middle Stone Age (MSA) deposits in Dar es-Soltan 1 cave on the Atlantic coast of Morocco. It comes from a layer that can be securely dated to ~90 ka. The typological characteristics of this tool, which suggest its manufacture and use as a bone knife, are comparatively similar to other bone artefacts from dated Aterian levels at the nearby site of El Mnasra and significantly different from any other African MSA bone technology. The new find from Dar es-Soltan 1 cave combined with those from El Mnasra suggest the development of a bone technology unique to the Aterian

Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study

Background: A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Methods: Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC) generated during the tasks were measured using a direct reading instrument (DRI) with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Results: Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred during mirror cleaning. Conclusions: Our results indicate that airborne exposures from short-term cleaning tasks can remain in the air even after tasks' cessation, suggesting potential exposures to anyone entering the room shortly after cleaning. Additionally, 2-BE concentrations from cleaning could approach occupational exposure limits and warrant further investigation. Measurement methods applied in this study can be useful for workplace assessment of airborne exposures during cleaning, if the limitations identified here are addressed