103 research outputs found

    Chemical characterisation of cherts from the valley of Serpis river (Alcoy, Alicante) for archaeological purpose

    Get PDF
    Mobility range and territorial control are central questions for Archaeology in the study of human groups’ life during Prehistoric Ages. A key point to get to grips with this set of problems is to understand the dynamics of supply of natural resources such as food and raw materials. Thus, the identification of the outcrops of chert and their characterisation is essential, due to the use of this particular rock as raw material for the production of several different tools. Since the nakedeye description of stone characters (colour, translucency, presence of carbonatation or patina, etc.) often lacks to identify different outcrops and to determine the provenance of a sample, in the last decades, scientists have tried to develop methods to improve the characterisation of this rock from the chemical, mineralogical and petrographic point of view [1,2]. This contribution shows the study of some chert varieties which were widely used since the Paleolithic by the inhabitants of the valley of Serpis river [3], in the southern part of the Valencian Community. Forty-three samples of Serrat, Mariola and Serreta chert were collected from different kinds of outcrops: from the wall rock, and from fluvial and colluvial deposits. The cortex or crust and the nucleus of each sample were mechanically separated and individually analysed to control the variability caused by the amount of cortex and consequently to develop a methodological approach that permits to identify different chert sources in a restricted area. For this purpose, Xray fluorescence and Inductively coupled plasma mass spectrometry analyses have been carried out to determine major elements, trace elements and rare earth elements [4] of cherts affected by different depositional and post-depositional conditions. [1] Luedtke, An Archaeologist's Guide to Chert and Flint (1992) 172. [2] Skarpelis et al., J. Archaeolog. Sci.: Rep. 12 (2017) 819. [3] Molina Hernández, El sílex del Prebético y cuencas neógenas en Alicante y sur de Valencia :su caracterización y estudio aplicado al Paleolítico Medio, tesis doctoral (2015) 902. [4] Murray, Sediment. Geol. 90 (1994) 213

    A Q model investment system in material and immaterial assets

    Get PDF
    The aim of this paper is to study the determinants of investment on material and immaterial assets of Spanish firms considering they are heterogeneous assets. With this objective, we propose an investment model based on both prospective models and Tobin’s q. The developed model is then applied to analyse the investment determinants of material and immaterial assets over a panel of 87 non-financial Spanish firms that have been quoting on the Stock Market during 12 years. Results show that material investment decisions are isolated from immaterial assets, whereas immaterial investment is affected by tangible investment and stock.This paper was developed under the objectives of the CREVALOR Research Group (DGASpain). It was financed by MEC-FEDER Research Project SEJ2005-07341.peer-reviewe

    Rare Earth Elements to identify archaeological strata in the Cocina Cave

    Get PDF
    Rare earth elements (REE) have been employed in a variety of different scenarios in order to identify the natural or anthropogenic nature of archaeological soils [1,2] . In this study, REE signatures were employed to better understand the layers formation in a cavity called Cocina cave, a large cavity of 300 m2 located at Barranco de la Ventana, one of the ravines flowing southwards from La Canal valley, a little plateau located in the municipality of Dos Aguas (Valencia, Spain). Cocina cave is characterized of very homogenous sediment deposition where it is difficult to understand layers formation processes just employing the traditional archaeological methods and the standardized soil analyses. The archaeological sequence encompasses last hunter-gatherer Holocene occupations in the regional sequence (Mesolithic) followed by several levels attributed to the Neolithic, Bronze Age and historic occupations until the XX century, these last regarding the use of the cavity as a pen. In order to understand the development history of the strata and the anthropogenic or natural formation of soils a total of fifty samples were taken across six different sections (A, B, C, D, E, F, G) and from each section the sampling was carried out at different depths through 1-2m deep sections. All samples were recovered from current pits excavated at the cavity corresponding with some profiles that encompass different strata including natural deposits and hunter and penning activities together with other possible uses not well defined from archaeological data. Several radiocarbon dates confirm the anthropogenic use of the cavity from the IX millennium cal BP to the contemporary times. Major, minor and trace elements including REE were determined employing XRF and ICP- MS. Results were then statistically processed and cross-referenced with archaeological data to aid interpretation. The results show that REE provide interesting details regarding the strata development history, and therefore help archaeologists to better understand the occupation, use and abandonment phases of the cave. [1] Pastor et al., TrAC 78 (2016) 48. [2] Gallello et al., JAS 40 (2013) 799

    Impact of Plasmodium falciparum pfhrp2 and pfhrp3 gene deletions on malaria control worldwide: a systematic review and meta-analysis

    Get PDF
    Background: Deletion of pfhrp2 and/or pfhrp3 genes cause false negatives in malaria rapid diagnostic test (RDT) and threating malaria control strategies. This systematic review aims to assess the main methodological aspects in the study of pfhrp2 and pfhrp3 gene deletions and its global epidemiological status, with special focus on their distribution in Africa; and its possible impact in RDT. Methods: The systematic review was conducted by examining the principal issues of study design and methodological workflow of studies addressing pfhrp2 deletion. Meta-analysis was applied to represent reported prevalences of pfhrp2 and pfhrp3 single and double deletion in the World Health Organization (WHO) region. Pooled-prevalence of deletions was calculated using DerSimonnian-Laird random effect model. Then, in-deep analysis focused on Africa was performed to assess possible variables related with these deletions. Finally, the impact of these deletions in RDT results was analysed combining reported information about RDT sensitivity and deletion prevalences. Results: 49 articles were included for the systematic review and 37 for the meta-analysis, 13 of them placed in Africa. Study design differs significantly, especially in terms of population sample and information reported, resulting in high heterogeneity between studies that difficulties comparisons and merged conclusions. Reported prevalences vary widely in all the WHO regions, significantly higher deletion were reported in South-Central America, following by Africa and Asia. Pfhrp3 deletion is more prevalent (43% in South-Central America; 3% in Africa; and 1% in Asia) than pfhrp2 deletion (18% in South-Central America; 4% in Africa; and 3% in Asia) worldwide. In Africa, there were not found differences in deletion prevalence by geographical or population origin of samples. The prevalence of deletion among false negatives ranged from 0 to 100% in Africa, but in Asia and South-Central America was only up to 90% and 48%, respectively, showing substantial relation between deletions and false negatives. Conclusion: The concerning prevalence of pfhrp2, pfhrp3 and pfhrp2/3 gene deletions, as its possible implications in malaria control, highlights the importance of regular and systematic surveillance of these deletions. This review has also outlined that a standardized methodology could play a key role to ensure comparability between studies to get global conclusions.I.M.F. received a research fellowship from the University of Alcalá that enables her to develop this study.S

    Análisis químicos no destructivos sobre cinco mangos de marfil de Época Ibérica

    Get PDF
    Presentamos los análisis químicos realizados sobre un conjunto de cinco mangos de marfil época ibérica (s. VI – s. I a. C.). Son objetos con características técnicas, formales y decorativas muy similares entre sí, lo que que permite plantear una relación entre ellos en su proceso de producción. Sin embargo, fueron recuperados en cuatro yacimientos diferentes del área ibérica: los poblados de Turó de Montgròs (El Brull, Barcelona) y La Serreta (Alcoi, Alicante) y las necrópolis de El Cigarralejo (Mula, Murcia) y Coimbra del Barranco Ancho (Jumilla, Murcia), en esta última, se recuperaron dos de ellos. Todas las piezas, por sus contextos arqueológicos se datan entre el s. IV y principios del s. II a. C. Los análisis se llevaron a cabo con el objetivo de identificar la naturaleza y procedencia de las incrustaciones de carácter decorativo y la sustancia adherente todavía presentes en estos mangos. Si bien, en algunos de ellos, debido a su deteriorado estado de conservación, únicamente quedaban las improntas de las incrustaciones y no había restos aparentes de la sustancia de tono gris-negro que, presumiblemente, serviría para adherir las incrustaciones. Las piezas mejor conservadas son las recuperadas en lugares de hábitat. Los estudios se han realizado mediante técnicas no destructivas que no comprometiesen la integridad de las piezas. Así, se llevaron a cabo análisis por Fluorescencia de Rayos X (XRF), y por Espectrofotometría de Infrarrojo Cercano por Transformada de Fourier (FT-NIR). Todo ello se complementó mediante la revisión de los mangos con un microscopio electrónico de barrido equipado con un Sistema de Rayos X de Energía Dispersiva (SEM-EDAX-Sapphire), un microscopio óptico SMZ (NIKON) y un microscopio digital Dino-lite mod. AM7115MZT EDGE de 10x a 200x con una luz incidente por medio de un iluminador de fibra óptica y dotado de un software con funciones de medición integrales, para obtener imágenes de alta precisión. El análisis de XRF ha permitido identificar como estaño la sustancia empleada para adherir las incrustaciones decorativas en la pieza, empleando una técnica de tipo soldadura blanda. El FTNIR, por su parte, ha revelado que dichas incrustaciones fueron realizadas sobre resinas fósiles, muy probablemente ámbar. Estos resultados resultan totalmente novedosos dentro del mundo artesanal de época ibérica y, por tanto, de gran interés, evidenciando el valor de estas piezas en las que materias primas de presencia escasa en el mundo ibérico como son el marfil y el ámbar aparecen combinadas; así como el uso del estaño a modo de soldadura blanda nos revela procesos de manufactura no atestiguados hasta el momento en las industrias sobre materias duras de origen animal de la Edad del Hierro en la Península Ibérica. Cabe destacar que la realización de análisis químicos sobre piezas arqueológicas aporta datos específicos, prácticamente imposibles de obtener en un estudio macro o microscópico de los artefactos. Por ello, desde el proyecto proyecto “Madera, hueso, marfil, asta, concha ¿Artesanías marginales o marginadas?” (HAR2013-45770-P y ACOMP/2015/256) (financiado por el Ministerio de Economía y Competitividad y la Generalitat Valenciana) dirigido por la Dra. Consuelo Mata, se ha apostado por desarrollar estudios interdisciplinares, que impliquen el contacto y la comunicación entre distintos especialistas con la finalidad de conseguir resultados más sólidos y transversales

    Chemical characterisation of historic mortars to evaluate decay and construction phases

    Get PDF
    The chemical characterization of ancient mortars allowed the researchers to answer relevant questions about production technologies, raw materials supply, construction phases and state of decay. In this work one hundred and sixteen samples were collected from different structures during two archaeological excavations carried out in Sagunto’s city centre (Valencia, Spain). The studied area has been interested by several continuous phases of occupation since the Iberian Epoch (5th century BC) to the present times [1,2]. The samples were analysed employing X-ray fluorescence and Inductively coupled plasma mass spectrometry to determine major and trace elements. The obtained data was statistically processed with Sagunto’s Castle mortar results [3], allowing us to identify the construction phases of most of the wall structures, confirming the particular effectiveness of Rare Earth Elements analysis to distinguish mortars from different periods. In conclusion, according to this data, the state of conservation of the different mortars has been evaluated. [1] Ripollés, Opulentissima Saguntum (2004) 165. [2] Monserrat, Arse 41 (2007) 231. [3] Gallello et al., Microchem. J. 132 (2017) 251

    Rare Earth Elements analysis to identify anthropogenic signatures at Valle del Serpis (Spain) Neolithic settlements

    Get PDF
    Due to their particular geochemical properties and stability Rare Earth Elements (REE) can act as a ‘fingerprint’ for soils, and as a consequence have been employed in a variety of different archaeological scenarios in order to identify past human activities.In this study, for the first time, we apply REE signatures in different Spanish Neolithic settlements, all located in the Valle del Serpis region. More than 100 Neolithic settlements have been identified in this area, and most of these open sites are characterised by dark brown strata that are in contrast with the light brown soils of the valley. These dark brown deposits are usually covered by paleosols and have been interpreted as markers of anthropogenic activities. However, in order to demonstrate whether these strata are anthropogenic or natural features requires a better understand-ing of soil development processes. A total of fifty samples were taken across six different sites, and from each site the sam-pling was carried out at different depths through 3m deep sections. Four sites are clearly associated with archaeological findings (sites BF, LP, PB and AC); another one is from a natural section near the Neolithic site of Mas d’Is (MD) and has been radiocarbon dated to the beginning of the Holocene (7751-7611 cal BC); and the last corresponds to a place of uncertain attribution (BK). Major, minor and trace elements including REE were determined using XRF and ICP- MS, with Principal Components Analysis (PCA) used to statistically analyze these data. Results were then compared with the strata soil properties analysed by XRD and particle size analysis, and cross-referenced with archaeological data to aid interpretation. The results demonstrate that REE analyses provide significant details regarding anthropogenic activities and strata development history, and in this instance confirm and elaborate on the archaeological interpretation that these dark brown deposits are evidence of a region-wide agricultural system in the Neolithic Valle del Serpis

    Chronological classification of ancient mortars employing spectroscopy and spectrometry techniques : Sagunto (Valencia, Spain) case

    Get PDF
    Forty-two mortar samples, from two archaeological excavations located in Sagunto (Valencian Community, Spain), were analysed by both portable energy dispersive X-ray fluorescence spectroscopy (pED-XRF) and inductively coupled plasma mass spectrometry (ICP-MS) to determine major and minor elements, and traces including rare earth elements (REE). Collected data were crossed with those previously obtained from Sagunto Castle mortars and principal component analysis (PCA) was applied to discriminate the construction phases of the unearthed buildings. REE permitted to ascribe most of the masonries to the Roman Imperial period. Moreover, a statistical model was built by employing partial least squares discriminant analysis (PLS-DA) in order to classify the mortars from Roman Imperial period and from Islamic period, due to the problematic overlapping between these two phases. Results confirmed the effectiveness of the developed indirect chronology method, based on REE data, to discriminate among historic mortars from different construction periods on a wide scale including different Sagunto archaeological sites

    Burned bones forensic investigations employing near infrared spectroscopy

    Get PDF
    The use of near infrared (NIR) spectroscopy was evaluated, by using chemometric tools, for the study of the environmental impact on burned bones. Spectra of internal and external parts of burned bones, together with sediment samples, were treated by Principal Component Analysis and cluster classification as exploratory techniques to select burned bone samples, less affected by environmental processes, to properly carry out forensic studies. Partial Least Square Discriminant Analysis was used to build a model to classify bone samples based on their burning conditions, providing an efficient and accurate method to discern calcined and carbonized bone. Additionally, Partial Least Square regression models were built to predict calcium, magnesium and strontium concentration of bone samples from their NIR spectra, being obtained an accurate root mean square error of prediction of 5.2% for calcium. Furthermore a screen methodology, for magnesium and strontium prediction, with a RPD of 0.24 and 1.08 respectively, was developed
    corecore