Search

Extraordinary preservation of plant remains provides an insight into the construction and materials of bedding at Border Cave, South Africa. Towards the back of the cave there are particularly thick layers of desiccated and charred grass and our botanical study is from bulk samples of these approximately 60,000 to 40,000 year-old layers (Members 3 BS, 2 WA, 2 BS and 1 BS Lower C). More than one type of panicoid grass was identified, sedge nutlets were present in the older layers and in Member 2 WA particularly, eudicotyledon leaves were preserved. Plant bedding construction may have altered slightly over time with the use of sedges decreasing in favour of grass. A small item that appears to be woven monocotyledon leaf blades was recovered from Member 1 BS Lower C (42,600 years old), potentially making it the oldest evidence of simple weaving. The bedding is generally desiccated rather than burned, and often lies on an ash base. It is possible that the site's occupants burned old bedding to provide an ash base for fresh bedding. The unique preservation of desiccated plant material from as early as 60,000 years ago may in part be due to these ashy surfaces.

The detection of low-intensity light is a crucial issue in many aspects of science and technology. So far, the solution has involved extremely delicate and somewhat bulky devices, the photomultiplier tubes, providing high sensitivity but suffering from fragility and susceptibility to interference. The silicon photomultiplier (SiPM) is a solid-state photon detector that provides a new solution for a wide range of photometry applications in fields as diverse as medicine, biology, environmental science, chemistry, physics, and nuclear physics. SiPMs are on a par with conventional photomultiplier tubes (PMT) in terms of internal gain and photon detection efficiency, while they are undoubtedly superior in terms of mechanical robustness, compact size, electronic stability, low power consumption, and affordability. Our group has long been involved in ionizing radiation measurements based on light emitting sensors both for industrial nuclear technology applications and for hybrid diagnostic imaging techniques. In both cases, SiPMs offer the unquestionable advantages described in this review.

On the basis of recent advancements in both neuroscience and archaeology, we propose a plausible biocultural mechanism at the basis of cultural evolution. The proposed mechanism, which relies on the notions of cultural exaptation and cultural neural reuse, may account for the asynchronous, discontinuous, and patchy emergence of innovations around the globe. Cultural exaptation refers to the reuse of previously devised cultural features for new purposes. Cultural neural reuse refers to cases in which exposure to cultural practices induces the formation, activation, and stabilization of new functional and/or structural brain networks during the individual lifespan. The invention of writing is interpreted as a case of cultural exaptation of previous devices to record information, in use since at least the Early Later Stone Age and the beginning of the Upper Paleolithic (44,000 years before present). The measurable changes in brain structure and functioning caused by learning to read are proposed as an exemplar case of cultural neural reuse. It is argued that repeated cycles of cultural exaptation, development of appropriate strategies of cultural transmission, and ensuing cultural neural reuse represent the fundamental mechanism that has regulated the cultural evolution of our lineage. A general predictive model of when and under which circumstances the proposed mechanism should be expected to occur is proposed, and the relationship of our mechanism with gene-culture coevolutionary models is discussed.

This study analyzed the optically simulated luminescence (OSL) of borate glasses containing lithium carbonate and potassium carbonate. Borate glasses present desirable characteristics for dosimetry and have been extensively analyzed in relation to thermoluminescence (TL). Five formulations containing 20% of Li2CO3 and different amounts of B2O3 and K2CO3 were produced. Their OSL signal was analyzed following exposure to beta particles. The decay pattern typical of continuous wave stimulation (CW-OSL) was observed for all compositions. Depending on the parameter chosen to normalize the dose-response curve, the sensitivity range changed. If the initial OSL intensity was chosen as reference, the composition containing 65% B2O3 and 15% K2CO3 (named L15KB) presented the most intense signal. However, if the total area below the curve was considered, the composition containing 70% B2O3 and 10% K2CO3 (named L10KB) was the most sensitive. A comparison of the OSL decay for the two quoted compositions, after pre-heating to 200 °C for 10 s prior to the OSL readout, showed a slight change in the decay pattern compared to the absence of pre-heating. The pre-heating treatments also showed the correlation between the shallow traps and the fast component of the OSL decay for L15KB. For all compositions, an increase in dose implied an increase in emitted signal, and no saturation was observed between 0.1 Gy and 7 Gy.

Polysulphone films are the only type of UV passive dosimeters that are widely adopted for research and personal monitoring. Even though many studies concentrated on the development and characterization of these films, they still present some shortcomings. The more important limitations of them are that they can measure only UVB radiations and that they change color at 330 nm, requiring special equipment to read them. To overcome these limitations we developed an aqueous dosimeter that is sensitive to UVA, UVB and X-rays named Redox-Phen solution. This dosimeter is inexpensive and water equivalent, being made of more than 99 wt% of water. It changes color in the visible region upon irradiation, thus it can be measured via simple optical method, and an evaluation of the exposition can be made also by naked eyes.

Lumps of mineral pigments are the more widespread archaeological remains found at Mousterian sites that may have been used by Neanderthals for symbolic activities. The characterisation of their chemical composition is essential to identify behavioural consistencies in their selection, transformation, and use, reconstruct changes through time in Neanderthals cultural practices, and discuss the emergence of symbolic cultures. In the Dordogne department of France, hundreds of black lumps, often bearing traces of intentional modification, were recovered at Middle (MP) and Upper Palaeolithic (UP) sites. In this paper we apply particle-induced X-ray emission (PIXE) to a representative sample of black lumps recovered at three MP and four UP sites as well as eight geological outcrops from this region with the aim of using major, minor, and trace elements content to identify potential sources and explore intra- and inter-site variability in the use of black colouring matter. Results suggest that MP and UP communities systematically searched for and surveyed Mn-rich formations to collect Mn-rich lumps. Differences in composition indicate that archaeological lumps were collected at a number of different outcrops, not sampled in the present study. A higher compositional variability is observed at UP compared to MP sites with single cultural layers. This suggests that UP modern humans may have, in some cases, exploited a wider range of Mn-rich sources than Mousterian Neanderthals.

The Middle Stone Age in Africa The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens . Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ∼320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries. Science , this issue p. 86 , p. 90 , p. 95

The bowand arrowis thought to be a unique development of our species, signalling higherlevel cognitive functioning. How this technology originated and how we identify archaeological evidence for it are subjects of ongoing debate. Recent analysis of the putative bone arrow point from Sibudu Cave in South Africa, dated to 61.7±1.5kya, has provided important new insights. High-resolution CT scanning revealed heat and impactdamage in both the Sibudu point and in experimentally produced arrow points. Thesefeatures suggest that the Sibudu point was first used as an arrowhead for hunting, andafterwards was deposited in a hearth. Our results support the claim that bone weapon tips were used in South African hunting long before the Eurasian Upper Palaeolithic. Fil: Backwell, Lucinda Ruth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Estudios Sociales. Universidad Nacional de Tucumán. Instituto Superior de Estudios Sociales; Argentina Fil: Bradfield, Justin. University of the Witwatersrand; Sudáfrica Fil: Carlson, Kristian J.. University of Southern California; Estados Unidos Fil: Jashashvili, Tea. University of Southern California; Estados Unidos Fil: Wadley, Lyn. University of the Witwatersrand; Sudáfrica Fil: D'Errico, Francesco. Universite de Bordeaux; Francia

Fricke gel dosimeters produced with a matrix of Poly-vinyl alcohol (PVA) cross-linked with glutaraldehyde (GTA) were analyzed with magnetic resonance imaging (MRI). Previous studies based on spectrophotometry showed valuable dosimetric features of these gels in terms of X-ray sensitivity and diffusion of the ferric ions produced after irradiation. In this study, MRI was performed on the gels at 1.5 T with a clinical scanner in order to optimize the acquisition parameters and obtain high contrast between irradiated and non-irradiated samples. The PVA gels were found to offer good linearity in the range of 0–10 Gy and a stable signal for several hours after irradiation. The sensitivity was about 40% higher compared to gels produced with agarose as gelling agent. The effect of xylenol orange (XO) on the MRI signal was also investigated: gel dosimeters made without XO show higher sensitivity to x-rays than those made with XO. The dosimetric accuracy of the 3D gels was investigated by comparing their MRI response to percentage depth dose and transversal dose profile measurements made with an ionization chamber in a water phantom. The comparison of PVA-GTA gels with and without XO showed that the chelating agent reduces the MRI sensitivity of the gels. Depth-dose and transversal dose profiles acquired by PVA-GTA gels without XO are more accurate and consistent with the ionization chamber data. However, diffusion effects hinder accurate measurements in the steep dose gradient regions and they should be further reduced by modifying the gel matrix and/or by minimizing the delay between irradiation and imaging.

International audience; Bone tool-use by Early Pleistocene hominins is at the center of debates in human evolution. It is especially the case in South Africa, where bone tools have been described from four Early Stone Age (ESA) archaeological sites, which have yielded Oldowan and possibly Acheulean artefacts, as well as Paranthropus robustus and early Homo remains. Here we describe a bone tool from Cooper's D. The deposit, dated between 1.4 and 1.0 Ma, has yielded seven P. robustus remains and 50 stone artefacts. Our results highlight similarities in morphology and use-wear patterns between the Cooper's D bone tool and those previously identified at nearby Sterkfontein, Swartkrans, Kromdraai and Drimolen. Our findings increase the number of Early Stone Age bone tools and provide further evidence of their association with P. robustus. They suggest P. robustus had the cognitive capacities to develop this cultural adaptation and the manipulative abilities to implement it.

Beads are a communication technology used by humans to transmit information on the wearer identity to members of the same or neighbouring groups by means of a shared symbolic language. Here we focus on the earliest evidence from Eastern Asia of a communication technology – the production of artificially coloured beads – that has allowed humans to further complexify the messages conveyed by personal ornaments, and associate, to some extent, the performance characteristics of beads and pigment. We study six ochred ostrich eggshell beads (OESB) from Shuidonggou Locality 2 (SDG2), Cultural Layer (CL) 2, China, dated to c. 31 kyr cal BP. Analysis of the beads manufacturing technique, size, and wear, combined with SEM-EDS and µ-Raman spectroscopy (µ-RS) study of well-preserved red residues sampled on the beads and sediment from CL2 indicate that these beads come from body ornaments and that red residues are the remnant of a pigmented compound coating the beads at the time they were worn by the SDG Palaeolithic visitors. SDG2-CL2 red stained OESBs thus represent, with the red stained bone disk from Xiaogushan, the earliest consistent evidence of pigment use for symbolic activities from China. Results also identify variations in the composition of the pigmental compound used to colour the beads that closely match differences in bead technology, size, and style. We argue that such a hitherto unknown consistency in bead production and decoration may reflect technological, morphological, and pigment coating standardisation at the individual level, standardisation in technology associated with variation in morphology and pigment at the group level, and substantial differences in these three domains at inter-group level.

A parametric study was performed examining the effect on CR-39 neutron dosimeters of pre-etching treatments with carbon dioxide at different pressures and durations. The detectors were irradiated with an 241Am-Be neutron source in our low-scatter laboratory, delivering a personal dose equivalent Hp(10) of 1 mSv. Prior to their chemical etching, the detectors were treated for times ranging from 1 to 5 days in carbon dioxide at pressures ranging from 0.1 to 0.5 MPa. In agreement with previous studies, track densities were found to increase following treatments of increasing duration and pressures. Our particular interest was examining the differential track size distributions produced by the treatments. In particular, we analyzed the track size distributions for untreated detectors versus detectors treated with a CO2 partial pressure of 0.5 MPa for 1, 3 and 5 days. Overall, the track size distribution appears to shift to higher diameters with increasing treatment time, while the overall pattern appears largely preserved. This “signature” may be associated with the energy distribution of the neutrons. In turn, this may allow establishing “adaptive” track-to-dose conversion coefficients accounting for the energy dependence of the CR-39 dose equivalent response.

Aircrew members are exposed to primary cosmic rays as well as to secondary radiations from the interaction of cosmic rays with the atmosphere and with the aircraft. The radiation field at flight altitudes comprises neutrons, protons, electrons, positrons, photons, muons and pions. Generally, 50% of the effective dose to airplane passengers is due to neutrons. Care must be taken especially with pregnant aircrew members and frequent fliers so that the equivalent dose to the fetus will not exceed prescribed limits during pregnancy (1 mSv according to ICRP, and 5 mSv according to NCRP). Therefore, it is necessary to evaluate the equivalent dose to a fetus in the maternal womb. Up to now, the equivalent dose rate to a fetus at commercial flight altitudes was obtained using stylized pregnant-female phantom models. The aim of this study was calculating neutron fluence to dose conversion coefficients for a fetus of six months of gestation age using a new, realistic pregnant-female mesh-phantom. The equivalent dose rate to a fetus during an intercontinental flight was also calculated by folding our conversion coefficients with published spectral neutron flux data. The calculated equivalent dose rate to the fetus was 2.35 μSv.h −1 , that is 1.5 times higher than equivalent dose rates reported in the literature. The neutron fluence to dose conversion coefficients for the fetus calculated in this study were 2.7, 3.1 and 3.9 times higher than those from previous studies using fetus models of 3, 6 and 9 months of gestation age, respectively. The differences between our study and data from the literature highlight the importance of using more realistic anthropomorphic phantoms to estimate doses to a fetus in pregnant aircrew members.

Studies on the optical absorbance spectra of Fricke xylenol orange gel dosimeters were performed, in the wavelength range from 300 nm to 800 nm, in order to highlight some particular characteristics that can affect the achievable precision. The spectra are different mainly due to the different types of xylenol orange that was used and to a lower extent due to the different gelling agents (agarose or gelatine). The characteristic of variation of absorbance spectra versus dose, however, are similar in the various cases and can explain some peculiarities, as apparent effects of dose threshold. Changes of spectral shapes appear over the time after irradiation. Magnetic resonance measurements performed at various times after irradiation only reveal the slow changes due to the auto-oxidation effect, proving therefore that the modality of chelation of ferric ions by xylenol orange can affect the observed changes in the optical absorbance spectra.

Measuring entrance exposures to diagnostic or therapeutic radiology patients is valuable to infer dose distributions within their bodies in order to minimize unnecessary exposures. For this purpose, we investigated the development of dosimeters consisting of waterproof, transparent, and flexible films containing OSL microcrystals. In our method, films are produced by casting solutions, followed by solvent evaporation. Non-aggressive chemicals are used, which allows the production of films containing large quantities of crystals without altering their structure. In this proof of principle study, we chose polyvinyl chloride (PVC) as a polymer matrix due to its high transparency and its waterproof nature and we produced films loaded with microcrystals of CaF 2 :Ce. A mixture of acetone:benzene (40:60 wt%) was selected as the best solvent for producing PVC films loaded with CaF 2 :Ce crystals. This solvent offers ease of handling, low toxicity, low cost, and does not affect the crystal structure nor its OSL emission. The PVC films can be loaded with any luminescent material. For proof of concept we chose to load them with CaF 2 :Ce micron sized particles because they emit an intense OSL signal for a low beta dose of 100 mGy, showing very good sensitivity for dosimetric applications. Our results indicate that films loaded with OSL crystals may be suitable for the production of a novel OSL dosimeter, which adheres closely to the body and could be used during a radiological procedure to estimate the entrance dose. As OSL materials are sensitive to light, somehow the films would have to be shielded from light for dosimetric purposes.

Current radiotherapy techniques implement treatment plans based on volumetric distributions of dose with complex shapes and sharp gradients. To verify the agreement between these treatment plans and the dose that is actually delivered, a dosimetric system that is truly three dimensional, sensitive to radiation in each point and tissue equivalent is required. For this purpose, we developed a radio-chromic gel based on polyvinyl alcohol (PVA), that is chemically cross-linked with glutaraldehyde (GTA) and offers high sensitivity and stability, i.e., low diffusion, of the signal. This gel is transparent and therefore it can be read out with optical techniques. The dosimetric characteristics of the PVA-GTA gel were compared to gelatine and to literature data for so called PVA hydrogels and cryogels. The dose response of the PVA-GTA dosimeter is found to be linear between 0 and 30 Gy and its sensitivity higher than any previously reported value for PVA-based gel dosimeters. The diffusion coefficient of the PVA-GTA gel is lower than the diffusion coefficient of gel with matrixes made by natural polymers.

We report the results of a detailed analysis of ostrich eggshell (OES) beads derived mainly from Cultural Layer 2 (CL2) of Locality 2 at the Shuidonggou site (SDG2) in North China, which is dated to ca. 31 ka cal BP. The eggshells belong to the extinct ostrich Struthio anderssoni. Based on microscopic examination, morphometric analysis, and experimental replication, we identify clear differences in morphology, size, technology, and style. Results indicate that the technology of bead making is similar to that used in most Middle and Later Stone Age sites in Africa and recorded ethnographically. Both well-made and poorly-crafted OES beads were produced at SDG2. Drilling experiments conducted in the framework of this study show that hafted stone points were probably used to make the perforations. Only occasionally beads were deliberately polished on inner and outer eggshell surfaces. Beads morphology and technology suggest that distinct types of beads were made by different individual craftspeople. This supports the hypothesis that several human groups visited the Shuidonggou site and used OES beads as an information technology about 31 ka cal BP.

In the following article, I will try to describe and, thus, share with my readers those moments and those segments in my life that have allowed me to be involved in the experience of musical improv...

The archaeological record shows that typically human cultural traits emerged at different times, in different parts of the world, and among different hominin taxa. This pattern suggests that their emergence is the outcome of complex and nonlinear evolutionary trajectories, influenced by environmental, demographic, and social factors, that need to be understood and traced at regional scales. The application of predictive algorithms using archaeological and paleoenvironmental data allows one to estimate the ecological niches occupied by past human populations and identify niche changes through time, thus providing the possibility of investigating relationships between cultural innovations and possible niche shifts. By using such methods to examine two key southern Africa archaeological cultures, the Still Bay [76–71 thousand years before present (ka)] and the Howiesons Poort (HP; 66–59 ka), we identify a niche shift characterized by a significant expansion in the breadth of the HP ecological niche. This expansion is coincident with aridification occurring across Marine Isotope Stage 4 ( ca. 72–60 ka) and especially pronounced at 60 ka. We argue that this niche shift was made possible by the development of a flexible technological system, reliant on composite tools and cultural transmission strategies based more on “product copying” rather than “process copying.” These results counter the one niche/one human taxon equation. They indicate that what makes our cultures, and probably the cultures of other members of our lineage, unique is their flexibility and ability to produce innovations that allow a population to shift its ecological niche.

The Malapa site has yielded unusually abundant and well preserved fossils of Australopithecus sediba. While some elements were found in situ during excavation, others were recovered ex situ from blocks of clastic, calcified sediments collected around the site. We have refitted the ex situ elements from Facies D, the sedimentary unit represented by a single debris flow from which most of the Au. sediba remains were collected, with the elements recovered in situ. Results confirm that the fossils in this unit can securely be attributed to two near-complete skeletons of a juvenile male (MH1), which initially lay in the upper, laminated part of Facies D, and an adult female (MH2), deposited in the lower part of this facies. We propose a description of peri- and postmortem events based on the location and orientation of the fossils, using for the first time a 3D reconstruction of the postulated position in which the two hominins were deposited. Macro- and microscopic modifications of bone surfaces, and degree of preservation confirm that the individuals were washed into the deposit as articulated—or semi-articulated—complete bodies, which were subaerially exposed for some time, and had reached natural mummification before being deposited within a debris flow.

We present the detailed analysis of a cervical vertebra from a cave bear, found at Pesturina cave, Serbia, in a Mousterian archaeological level dated by radiocarbon at 43.5–44.6 kyr cal BP, and by ESR to between 93.5 and 102.5 kyr BP. Identified as a portion of the cranial articular facet, the fragment displays ten subparallel grooves. The microscopic study of these grooves and other surface modification present on the bone fragment, conducted with multifocus optical and confocal microscopes and complemented by a taphonomic analysis of the associated faunal assemblage, supports the hypothesis that the incisions were made by humans. Results are used to critically examine ambiguities implicit in the analysis and interpretation of early engravings, a category of material culture that has been playing a key role in the identification of early instances of symbolically mediated behavior.

This work describes the preliminary analysis of Fricke gels dosimeters characterized by a new formulation making use of a matrix of polyvinyl alcohol cross-linked by adding glutaraldehyde and analyzed by means of nuclear magnetic resonance relaxometry. In previous optical studies, these gels have shown promising dosimetric features in terms of photon sensitivity and low diffusion of ferric ions produced after irradiation. In this work, we used a portable nuclear magnetic resonance relaxometer to measure the relaxation times (which are important for dosimetric applications) of these gel materials. For this purpose, we performed a study for optimizing the acquisition parameters with a nuclear magnetic resonance relaxometer. Gel samples were exposed to clinical 6 MV photons in the dose range between 0 and 20 Gy. Nuclear magnetic resonance relaxometry measurements were per- formed and the sensitivity to photon beams was measured for various values of the Fe2+ ion concentration. The analyses pointed out that the MR signal increases as the Fe2+ content in- creases and the increase is about 75 % when the concentration of Fe2+ ions is increased from 0.5 mM to 2.5 mM. Furthermore, the sensitivity improvement achieved with increasing the Fe2+ concentration is about 60 %. This paper shows that the portable nuclear magnetic resonance relaxometer used for analysis of porous materials can be used for characterization of these dosimetric gels and this study can be considered as the first step for the characterization of these dosimeters which in future could be used for 3-D dose mapping in clinical applications.

Dysfunction of NMDA receptor (NMDAR)-mediated transmission is supposed to contribute to the motor and non-motor symptoms of Parkinson's Disease (PD), and to L-DOPA-induced dyskinesia. Besides the main agonist L-glutamate, two other amino acids in the atypical D-configuration, D-serine and D-aspartate, activate NMDARs. In the present work, we investigated the effect of dopamine depletion on D-amino acids metabolism in the brain of MPTP-lesioned Macaca mulatta, and in the serum and cerebrospinal fluid of PD patients. We found that MPTP treatment increases D-aspartate and D-serine in the monkey putamen while L-DOPA rescues both D-amino acids levels. Conversely, dopaminergic denervation is associated with selective D-serine reduction in the substantia nigra. Such decrease suggests that the beneficial effect of D-serine adjuvant therapy previously reported in PD patients may derive from the normalization of endogenous D-serine levels and consequent improvement of nigrostriatal hypoglutamatergic transmission at glycine binding site. We also found reduced D-serine concentration in the cerebrospinal fluid of L-DOPA-free PD patients. These results further confirm the existence of deep interaction between dopaminergic and glutamatergic neurotransmission in PD and disclose a possible direct influence of D-amino acids variations in the changes of NMDAR transmission occurring under dopamine denervation and L-DOPA therapy. Dysfunction of NMDA receptor (NMDAR)-mediated transmission is supposed to contribute to the motor and non-motor symptoms of Parkinson’s Disease (PD), and to L-DOPA-induced dyskinesia. Besides the main agonist L-glutamate, two other amino acids in the atypical D-configuration, D-serine and D-aspartate, activate NMDARs. In the present work, we investigated the effect of dopamine depletion on D-amino acids metabolism in the brain of MPTP-lesioned Macaca mulatta, and in the serum and cerebrospinal fluid of PD patients. We found that MPTP treatment increases D-aspartate and D-serine in the monkey putamen while L-DOPA rescues both D-amino acids levels. Conversely, dopaminergic denervation is associated with selective D-serine reduction in the substantia nigra. Such decrease suggests that the beneficial effect of D-serine adjuvant therapy previously reported in PD patients may derive from the normalization of endogenous D-serine levels and consequent improvement of nigrostriatal hypoglutamatergic transmission at glycine binding site. We also found reduced D-serine concentration in the cerebrospinal fluid of L-DOPA-free PD patients. These results further confirm the existence of deep interaction between dopaminergic and glutamatergic neurotransmission in PD and disclose a possible direct influence of D-amino acids variations in the changes of NMDAR transmission occurring under dopamine denervation and L-DOPA therapy.

Background Programmed epigenetic modifications occurring at early postnatal brain developmental stages may have a long-lasting impact on brain function and complex behavior throughout life. Notably, it is now emerging that several genes that undergo perinatal changes in DNA methylation are associated with neuropsychiatric disorders. In this context, we envisaged that epigenetic modifications during the perinatal period may potentially drive essential changes in the genes regulating brain levels of critical neuromodulators such as d-serine and d-aspartate. Dysfunction of this fine regulation may contribute to the genesis of schizophrenia or other mental disorders, in which altered levels of d-amino acids are found. We recently demonstrated that Ddo, the d-aspartate degradation gene, is actively demethylated to ultimately reduce d-aspartate levels. However, the role of epigenetics as a mechanism driving the regulation of appropriate d-ser levels during brain development has been poorly investigated to date. Methods We performed comprehensive ultradeep DNA methylation and hydroxymethylation profiling along with mRNA expression and HPLC-based d-amino acids level analyses of genes controlling the mammalian brain levels of d-serine and d-aspartate. DNA methylation changes occurring in specific cerebellar cell types were also investigated. We conducted high coverage targeted bisulfite sequencing by next-generation sequencing and single-molecule bioinformatic analysis. Results We report consistent spatiotemporal modifications occurring at the Dao gene during neonatal development in a specific brain region (the cerebellum) and within specific cell types (astrocytes) for the first time. Dynamic demethylation at two specific CpG sites located just downstream of the transcription start site was sufficient to strongly activate the Dao gene, ultimately promoting the complete physiological degradation of cerebellar d-serine a few days after mouse birth. High amount of 5′-hydroxymethylcytosine, exclusively detected at relevant CpG sites, strongly evoked the occurrence of an active demethylation process. Conclusion The present investigation demonstrates that robust and selective demethylation of two CpG sites is associated with postnatal activation of the Dao gene and consequent removal of d-serine within the mouse cerebellum. A single-molecule methylation approach applied at the Dao locus promises to identify different cell-type compositions and functions in different brain areas and developmental stages.

International audience; Located in the KwaZulu-Natal, 15 km from the coast, Sibudu has yielded twenty-three marine gastropods, nine of which are perforated. At 70.5 ± 2.0 ka, in a Still Bay Industry, there is a cluster of perforated Afrolittorina africana shells, one of which has red ochre stains. There is also a perforated Mancinella capensis and some unperforated shells of both A. africana and M. capensis. The cluster may represent an area where the shells were processed or where apparel to which shells were attached was lost. In a Howiesons Poort layer, 64.7 ± 1.9 ka, there is a single perforated Afrolittorina africana shell. This shell may be from the Still Bay and may have been dislodged by rock fall. Two Nassarius kraussianus shells, one of them perforated and bearing traces of utilisation as a bead, were found in a late Middle Stone Age layer with an OSL age of 46.6 ± 2.3 ka. N. kraussianus was not found in older layers, even though this taxon occurs in southern Cape sites during the Middle Stone Age. Where the perforations are undamaged and suitable for microscopy, they appear to have been made by punching the shells with a pointed tool made of bone or hard wood. Such perforations have been replicated experimentally. Unlike the Blombos beads, the Sibudu shells from the Still Bay and Howiesons Poort layers bear no compelling evidence of use wear in their perforations. We therefore cannot be certain that they were suspended. However, if the Sibudu shells were beads, the changing use of taxa through time suggests variability in symbolic traditions.

Island Southeast Asia (ISEA) is a key region for the study of human evolution. New fossil and archaeological evidence, from several islands, suggests an Early to Middle Pleistocene colonisation date by hominins. A taphonomic framework, however, such as that exists for Africa, is currently lacking, and taphonomical studies of ISEA vertebrate assemblages are very limited. In this paper, we apply multifocus and confocal microscopy to surface modifications on an Early to Middle Pleistocene avian assemblage from Mata Menge, in the So'a Basin of central Flores, Indonesia, with the aim of characterizing material and testing the relevance of 3D reconstructions to study the taphonomy of ISEA bone assemblages. Our observations document a number of bone surface modifications, including individual parallel grooves, overlapping spindle-like striations, elongated impacts, short composite grooves, and rows of pits. These features suggest that several taphonomic agents were at play during and after the accumulation of the Mata Menge small vertebrate assemblage. We find no unambiguous evidence for the exploitation of birds by the So'a Basin hominins, or for hominins being a significant accumulating agent of avian remains at Mata Menge. However, our work should be seen as preliminary, as direct comparative data on relevant biological agents are lacking. The markedly distinct faunal composition and climatic regimes of many Southeast Asian islands, and the potential use of different tools by hominins, warrants the development of a comprehensive taphonomical framework that is specifically relevant for ISEA. publishedVersion

International audience; The production of abstract engravings is considered an indicator of modern human cognition and a means for the long-term recording and transmission of information. This article reports the discovery of two engraved bones from the Lingjing site in Henan Province, China, dated to 105-125 kya. The carefully engraved nature of the incisions, made on weathered rib fragments, precludes the possibility of unintentional or utilitarian origins. Residue analysis demonstrates the presence of ochre within the incised lines on one specimen. This research provides the first evidence for the deliberate use of ochred engravings for symbolic purposes by East Asian Late Pleistocene hominins.

International audience; Neanderthal material culture patterning in Western Europe has been primarily approached from retouched stone tools and associated flake production methods. While considerable effort has been devoted over the past decade to better characterize Middle Palaeolithic lithic techno-complexes (LTCs) in this region, the extent to which they reflect cultural groups still remains unclear. In this respect, integrating other forms of archaeological evidence could provide valuable insights on the cultural significance of late Middle Palaeolithic industrial variability. The site of Combe-Grenal (Dordogne, France) has yielded consistent evidence of mineral pigment use throughout the upper part of the sequence. Here we explore whether mineral pigments might be embedded with an indexical meaning and if changes in pigment exploitation potentially reflect cultural changes. We combined a microscopic use-wear approach with SEM-EDS, pXRF, and XRD analyses of 73 pigment fragments from layers 26 to 11 in order to reconstruct the different stages of their acquisition and use (provenance, selection, processing, function). Our results show manganese oxides to have been used in the lower layers of the Quina LTC, while red and/or yellow iron oxide pieces were employed during the Discoid and Discoid/Levallois LTCs. This decrease in manganese oxide use correlates with a change in lithic technology and may represent some form of cultural change.

Fricke gel radiochemical sensors based on various matrices have been studied for decades as 3D dosimeters for radiotherapy. Despite their many appealing features, progressive aging and blurring of the signal have prevented the widespread use of these dosimeters, so far. We have addressed these shortcomings and hereby present our development of a Fricke gel based on a chemically cross-linked PVA matrix. We investigated the influence of several parameters of the polymeric matrix on sensitivity, diffusion coefficient and spontaneous oxidation of the proposed gel dosimeter. Based on these findings, we optimized the gel compositions. Our new gel formulation combines transparency, high sensitivity and simple production method, typical of gels based on natural polymers, with low diffusion coefficient and slow spontaneous oxidation typical of PVA gels made by freezing-thawing.

Purpose of this study is to test if possible effects of gelation temperature and pH on the cross-linking process between poly(vinyl alcohol) (PVA) and glutaraldehyde (GTA), have consequences on the dosimetric properties of PVA-GTA Xylenol Orange Fricke gel dosimeters. Therefore, dose-response curves and Fe3+ diffusion rate of PVA-GTA Fricke gel dosimeters prepared using different sulfuric acid concentrations and different gelation temperature were investigated by optical absorbance measurements. The results demonstrated that the sulfuric acid concentration determines both the dose sensitivity of the PVA-GTA Xylenol Orange Fricke gel dosimeters and the interval of linearity of the dose-response curve. Although the effects of gelation temperature and sulfuric acid concentration on the PVA-GTA cross-linking process may occur, no significant consequences on diffusion properties of PVA polymer network were observed. Indeed, Fe3+ diffusion rates in all investigated samples were very similar, and less than half of those achievable in Fricke gel dosimeters prepared with natural gel matrices like gelatin and agarose.

The Mu2e electromagnetic calorimeter is made of two disks of un-doped parallelepiped CsI crystals readout by SiPM. There are 674 crystals in one disk and each crystal is readout by an array of two SiPM. The readout electronics is composed of two types of modules: 1) the front-end module hosts the shaping amplifier and the high voltage linear regulator; since one front-end module is interfaced to one SiPM, a total of 2696 modules are needed for the entire calorimeter; 2) a waveform digitizer provides a further level of amplification and digitizes the SiPM signal at the sampling frequency of $200\ \text{M}\text{Hz}$ with 12-bits ADC resolution; since one board digitizes the data received from 20 SiPMs, a total of 136 boards are needed. The readout system operational conditions are hostile: ionization dose of $20\ \text{krads}$, neutron flux of $10^{12}\ \mathrm{n}(1\ \text{MeVeq})/\text{cm}^2$, magnetic field of $1\ \text{T}$ and in vacuum level of $10^{-4}\ \text{Torr}$. A description of the readout system and qualification tests is reported.

A new sensitization technique combining carbon dioxide and UV treatments was investigated for improved neutron dosimetry of CR-39 track detectors. The detectors were irradiated with an 241Am–Be neutron source in a low-scatter laboratory facility, delivering a personal dose equivalent Hp(10) of 1 mSv. Prior to their chemical etching, the detectors were treated in carbon dioxide at a pressure of 0.6 MPa for 6 days followed by a UV (254 nm) treatment at a distance of 5 cm from the lamp, for 20 h. The opposite, UV followed by carbon dioxide treatment, was also investigated. The qualitative impact of these treatments on the background noise of the detectors, and their track size distributions compared to only carbon dioxide, only UV treated detectors, and untreated ones was analysed. Overall, the technique combining CO2 and UV treatments, independently of their order, increased the sensitivity by about 40% and 120% compared to the UV treatment alone and the untreated detectors, respectively, and reduced approximately 15% compared to the CO2 treatment alone. It also significantly enhanced the average diameter of the tracks compared to both treatments separated, allowing a better distinction between real tracks and the noisy background.

Magnesium-tetraborates and lithium-tetraborates are excellent detectors for ionizing radiation. However, manufacturing these crystalline structures is challenging as it involves multi-step chemical processes and toxic reagents. Over the past decades, alternative production methods for crystals have been studied aiming at lowering production costs and environmental impact and at increasing production yield and reproducibility. Among these is the Pechini method, based on the formation of polymer chains containing uniformly distributed metal ions. Another method is a modified proteic sol–gel process using edible gelatins or coconut water instead of the alkoxides used in conventional processes. In this work, we searched optimal conditions for the synthesis of dosimetry-grade MgB4O7 and Li2B4O7 crystals with the Pechini and the proteic sol–gel methods. The crystal phases were characterized by X-ray diffraction and by thermal analyses. We determined that MgB4O7 can be synthesized either by calcination of the reagents at 900 °C for 2 h with the sol–gel approach, or at just 800 °C for 2 h with the Pechini method. Single-phase Li2B4O7 can be synthesized either by calcination of the reagents at 650 °C for 2 h with the sol–gel approach, or at just 600 °C for 2 h with the Pechini method. Our synthesis times and temperatures are lower than those reported in the literature, which reduces significantly production costs and environmental impact.

Purpose: This paper describes a method to achieve consistent clinical image quality in 18F-FDG scans accounting for patient habitus, dose regimen, image acquisition, and processing techniques. Methods: Oncological PET/CT scan data for 58 subjects were evaluated retrospectively to derive analytical curves that predict image quality. Patient noise equivalent count rate and coefficient of variation (CV) were used as metrics in their analysis. Optimized acquisition protocols were identified and prospectively applied to 179 subjects. Results: The adoption of different schemes for three body mass ranges ( 90 kg) allows improved image quality with both point spread function and ordered-subsets expectation maximization-3D reconstruction methods. The application of this methodology showed that CV improved significantly (p < 0.0001) in clinical practice. Conclusions: Consistent oncological PET/CT image quality on a high-performance scanner was achieved from an analysis of the relations existing between dose regimen, patient habitus, acquisition, and processing techniques. The proposed methodology may be used by PET/CT centers to develop protocols to standardize PET/CT imaging procedures and achieve better patient management and cost-effective operations.

Here we present the results of a techno-functional analysis of 17 bone tools recovered from strata 6, 5 and 3 of the Palaeolithic site of Ma'anshan Cave, Guizhou Province, southern China. Stratum 6, dated to c. 35 cal kyr BP, has yielded three sharp awls. From Stratum 5, dated to c. 34 cal kyr BP, come six probable spear points, awls and a cutting tool. Separated from these layers by a sterile horizon, Stratum 3, dated 23 cal kyr BP to 18 cal kyr BP, has yielded barbed points of two types. Bone tools were shaped by scraping, grinding, and in strata 5 and 3, finished by polishing. Ma'anshan Cave records the oldest formal bone tools from China, and amongst the oldest known evidence of indisputable barbed point manufacture outside Africa. Change in the hunting toolkit between strata 5 and 3 may indicate a shift in prey preference from medium to small size mammals and fish, which needs to be verified by supplementary analyses. The significance of this evidence is discussed in the context of what is known about the origin of bone tool technology in Africa and Eurasia.

The aim of this paper is to characterize the IRSL response of rare earth doped CaF2 and co-doped with Al or Li, produced by the solution combustion synthesis (SCS). The results showed a high intensity of the infrared optically stimulated luminescence (IRSL) response for the samples of CaF2 doped with Tb and co-doped with Li. For the samples of CaF2 doped with Ce and co-doped with Li present better IRSL response than the samples co-doped with Al. It was also observed that the samples of CaF2:Ce,Li present a high fading with 50% reduction of the IRSL signal in a period of 60 min. In case of the CaF2:Tb,Li there is no significant fading during this period. For clinical dosimetry the fast fading of the dosimeter is not adequate. However, this feature can be exploited for other applications such as tamper-proof passive systems that detect and timestamp the movement of undeclared nuclear materials, by the estimation of the OSL response of materials with different fading rates.

The purpose of this work is to highlight the effects of ionizing radiation on the genetic material in higher plants by assessing both adaptive processes as well as the evolution of plant species. The effects that the ionizing radiation has on greenery following a nuclear accident, was examined by taking the Chernobyl Nuclear Power Plant disaster as a case study. The genetic and evolutionary effects that ionizing radiation had on plants after the Chernobyl accident were highlighted. The response of biota to Chernobyl irradiation was a complex interaction among radiation dose, dose rate, temporal and spatial variation, varying radiation sensitivities of the different plants' species, and indirect effects from other events. Ionizing radiation causes water radiolysis, generating highly reactive oxygen species (ROS). ROS induce the rapid activation of detoxifying enzymes. DeoxyriboNucleic Acid (DNA) is the object of an attack by both, the hydroxyl ions and the radiation itself, thus triggering a mechanism both direct and indirect. The effects on DNA are harmful to the organism and the long-term development of the species. Dose-dependent aberrations in chromosomes are often observed after irradiation. Although multiple DNA repair mechanisms exist, double-strand breaks (DSBs or DNA-DSBs) are often subject to errors. Plants DSBs repair mechanisms mainly involve homologous and non-homologous dependent systems, the latter especially causing a loss of genetic information. Repeated ionizing radiation (acute or chronic) ensures that plants adapt, demonstrating radioresistance. An adaptive response has been suggested for this phenomenon. As a result, ionizing radiation influences the genetic structure, especially during chronic irradiation, reducing genetic variability. This reduction may be associated with the fact that particular plant species are more subject to chronic stress, confirming the adaptive theory. Therefore, the genomic effects of ionizing radiation demonstrate their likely involvement in the evolution of plant species.

Free d-aspartate is abundant in the mammalian embryonic brain. However, following the postnatal onset of the catabolic d-aspartate oxidase (DDO) activity, cerebral d-aspartate levels drastically decrease, remaining constantly low throughout life. d-Aspartate stimulates both glutamatergic NMDA receptors (NMDARs) and metabotropic Glu5 receptors. In rodents, short-term d-aspartate exposure increases spine density and synaptic plasticity, and improves cognition. Conversely, persistently high d-Asp levels produce NMDAR-dependent neurotoxic effects, leading to precocious neuroinflammation and cell death. These pieces of evidence highlight the dichotomous impact of d-aspartate signaling on NMDAR-dependent processes and, in turn, unveil a neuroprotective role for DDO in preventing the detrimental effects of excessive d-aspartate stimulation during aging. Here, we will focus on the in vivo influence of altered d-aspartate metabolism on the modulation of glutamatergic functions and its involvement in translational studies. Finally, preliminary data on the role of embryonic d-aspartate in the mouse brain will also be reviewed.

An extensive investigation was done of the sensitization effects of carbon dioxide pre-etching treatments on the tracks of CR-39 detectors exposed to fast neutrons. The detectors were irradiated with an 241AmBe neutron source in a low-scatter laboratory, delivering a personal dose equivalent Hp(10) of 1 mSv. Prior to the chemical etching, the detectors were treated in carbon dioxide at partial pressures ranging from 0.6 to 2.4 MPa for times ranging from 6 to 144 h. By examining treatments under pressures greater than 0.6 MPa, our goal was understanding the correlation between detector response and treatment time and optimizing the conditions for practical applications of CR-39 detectors in neutron dosimetry and spectrometry. From the analysis of the track size distribution for each treatment condition, we found a consistent trend regarding the increasing number of detected tracks. Moreover, by correlating the integral of these track distribution curves with the treatment time, we found a linear increase in detector sensitivity for all the investigated pressures, the first time such behavior is reported. This could help a dosimetry laboratory optimizing and adjusting the treatment time, while also improving the detector sensitivity.

In mammals, free d-aspartate (D-Asp) is abundant in the embryonic brain, while levels remain very low during adulthood as a result of the postnatal expression and activity of the catabolizing enzyme d-aspartate oxidase (DDO). Previous studies have shown that long-lasting exposure to nonphysiological, higher D-Asp concentrations in Ddo knockout (Ddo-/-) mice elicits a precocious decay of synaptic plasticity and cognitive functions, along with a dramatic age-dependent expression of active caspase 3, associated with increased cell death in different brain regions, including hippocampus, prefrontal cortex, and substantia nigra pars compacta. Here, we investigate the yet unclear molecular and cellular events associated with the exposure of abnormally high D-Asp concentrations in cortical primary neurons and in the brain of Ddo-/- mice. For the first time, our in vitro findings document that D-Asp induces in a time-, dose-, and NMDA receptor-dependent manner alterations in JNK and Tau phosphorylation levels, associated with pronounced cell death in primary cortical neurons. Moreover, observations obtained in Ddo-/- animals confirmed that high in vivo levels of D-Asp altered cortical JNK signaling, Tau phosphorylation and enhanced protein SUMOylation, indicating a robust indirect role of DDO activity in regulating these biochemical NMDA receptor-related processes. Finally, no gross modifications in D-Asp concentrations and DDO mRNA expression were detected in the cortex of patients with Alzheimer's disease when compared to age-matched healthy controls. In mammals, free D-aspartate (D-Asp) is abundant in the embryonic brain, while levels remain very low during adulthood as a result of the postnatal expression and activity of the catabolizing enzyme D-aspartate oxidase (DDO). Previous studies have shown that long-lasting exposure to nonphysiological, higher D-Asp concentrations in Ddo knockout (Ddo(-/-)) mice elicits a precocious decay of synaptic plasticity and cognitive functions, along with a dramatic age-dependent expression of active caspase 3, associated with increased cell death in different brain regions, including hippocampus, prefrontal cortex, and substantia nigra pars compacta. Here, we investigate the yet unclear molecular and cellular events associated with the exposure of abnormally high D-Asp concentrations in cortical primary neurons and in the brain of Ddo(-/-) mice. For the first time, our in vitro findings document that D-Asp induces in a time-, dose-, and NMDA receptor-dependent manner alterations in JNK and Tau phosphorylation levels, associated with pronounced cell death in primary cortical neurons, Moreover, observations obtained in Ddo(-/-) animals confirmed that high in vivo levels of D-Asp altered cortical JNK signaling, Tau phosphorylation and enhanced protein SUMOylation, indicating a robust indirect role of DDO activity in regulating these biochemical NMDA receptor-related processes. Finally, no gross modifications in D-Asp concentrations and DDO mRNA expression were detected in the cortex of patients with Alzheimer's disease when compared to age-matched healthy controls.

When, how, and following which paths hominins created the innovations that allowed them to colonize regions of the planet that were not suited to their thermal physiology is still a matter of inquiry. In this paper, we elaborate a theoretical framework to investigate the origin and diversification of bone needles, summarize the evidence for their emergence, create a large database of their morphometric and stylistic characters, and present results of the study of an exceptionally well-preserved collection of needles from Shuidonggou Locality 12 (SDG12), a site located in the Ningxia Hui Autonomous Region, Northern China, dated to ca. 11.2 ka BP. Bone needles are reported from 271 sites and 355 archaeological layers. Revision of the evidence shows they represent an original cultural innovation that emerged in Eurasia between 45–40 ka BP. Size differences between the earliest known specimens, found in Siberia and China, indicate needles may have been invented independently in these two regions. Needles from Eastern Europe may represent either an independent invention or a geographic extension of earlier Siberian and Caucasian sewing traditions. In Western Europe, needles appear during the Solutrean. The wider size range characteristic of Magdalenian specimens supports the idea that needles of different sizes were used in a variety of tasks. In China, the robust sub-circular needles found at sites dated between 35–25 ka BP are followed, between 26–23 ka BP, by small flat needles, which may represent an innovation associated with the microblades/microcores toolkit. At SDG12, technological, functional, and morphometric analyses of finished needles and manufacturing by-products identify two previously undetected reduction sequences for the production of needles of different size and, probably, function. The bone needles found at Paleoindian sites are the smallest and reflect a never previously achieved mastery in the production of such tools.

The earliest human graphic productions dating to the Lower and Middle Palaeolithic are associated with anatomically modern and archaic hominins. These productions, which consist of abstract patterns engraved on a variety of media, may have been used as symbols, and their emergence is thought to be associated with the evolution of the properties of the visual cortex. To test this hypothesis, we used functional magnetic resonance imaging to compare brain activations triggered by the perception of engraved patterns dating between 540,000 and 30,000 years before the present with those elicited by the perception of scenes, objects, symbol-like characters, and written words. The perception of the engravings bilaterally activated regions in the ventral route in a pattern similar to that produced by the perception of objects, suggesting that these graphic productions are processed as organized visual representations in the brain. Moreover, the perception of the engravings led to a leftward activation of the visual word form area. These results support the hypothesis that in contrast to random doodles, the earliest abstract graphic productions had a representational purpose for modern and archaic hominins.

Special nuclear materials hidden in shipping containers are extremely difficult to detect through their faint spontaneous emission of neutrons and photons. R&D efforts focus on active interrogation (AI) techniques, employing external beams of neutrons or high-energy X-rays to first trigger fission reactions and then detect prompt or delayed neutrons and/or photons. Our group created a complete active interrogation system based on detectors developed by the universities of Pisa and Yale and on an ultra-compact linear accelerator (LINAC). The detectors contain liquid droplets that vaporize when exposed to fast neutrons but are insensitive to X-rays. The X-ray generator is based on 9MeV electron LINAC developed by S.I.T. Sordina S.p.A. for intraoperative radiotherapy. The latter is a standing-wave design that does not require external solenoids for electron radial focusing. Copper is used both as X-ray production target and as collimator, which prevents the production of photo-neutrons. In our first tests, we detected depleted uranium, while excluding significant production of contaminant photo-neutrons.