640 research outputs found
Lightfastness assessment of Levantine rock art by means of microfading spectrometry
This is the peer reviewed version of the following article: del Hoyo-Meléndez JM,
Carrión-Ruiz B, Riutort-Mayol G, Lerma JL. Lightfastness assessment of Levantine rock art by means of microfading spectrometry. Color Res Appl. 2019;44:547 555, which has been published in final form at https://doi.org/10.1002/col.22372. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] The documentation of archeological sites requires the adoption of non-destructive techniques to safeguard the unique legacy coming from prehistoric periods. This article tackles the assessment of lightfastness properties on a rock art site to deter- mine the behavior of motif's color deterioration over time in Remi¿gia Cave, Castello¿n (Spain), which is considered part of a UNESCO World Heritage Site. The measurements were performed using a microfade testing device to analyze the spectral characteristics and the aging properties of the colorant system and various substrates on site. Two scenarios have been identified depending on whether the lightness (L*) parameter of the rocky substrate changes or not in relation with the painted motifs. If the substrate remains stable without any change, red motifs con- taining iron oxide pigments will become more visible. If the substrate becomes lighter, the pigments will experience similar changes. Therefore, the contrast between paintings and support will be considerably enhanced.The authors also would like to thank the Generalitat Valenciana for providing access to the site during the measurement campaigns. Fruitful comments from the Spanish
archeologists Prof. Valentín Villaverde and Dra. Esther
López-Montalvo are also gratefully acknowledged. The
authors acknowledge the research project HAR2014-59873-R
from the Spanish Ministerio de Economía y Competitividad
for providing financial support.Del Hoyo-Meléndez, JM.; Carrión-Ruiz, B.; Riutort-Mayol, G.; Lerma, JL. (2019). Lightfastness assessment of Levantine rock art by means of microfading spectrometry. Color Research & Application. 44(4):547-555. https://doi.org/10.1002/col.22372S547555444Vileikis, O., Cesaro, G., Santana Quintero, M., van Balen, K., Paolini, A., & Vafadari, A. (2012). Documentation in World Heritage conservation. Journal of Cultural Heritage Management and Sustainable Development, 2(2), 130-152. doi:10.1108/20441261211273635Management Planning for Archaelogical Sites 2002 The Getty Conservation Institute Los Angeles G Palumbo Threats and challenges to the archaeological heritage in the Mediterranean 3 12ICOMOS. ICOMOS World Report 2000 on Monuments and Sites in Danger; 2000.https://www.icomos.org/risk/world_report/2000/risk2000.htm. Accessed October 25 2017.Giesen, M. J., Ung, A., Warke, P. A., Christgen, B., Mazel, A. D., & Graham, D. W. (2014). Condition assessment and preservation of open-air rock art panels during environmental change. Journal of Cultural Heritage, 15(1), 49-56. doi:10.1016/j.culher.2013.01.013Díez-Herrero, A., Gutiérrez-Pérez, I., Lario, J., Cañaveras, J. C., Benavente, D., Sánchez-Moral, S., & Alonso-Azcárate, J. (2009). Analysis of potential direct insolation as a degradation factor of cave paintings in Villar del Humo, Cuenca, Central Spain. Geoarchaeology, 24(4), 450-465. doi:10.1002/gea.20274López-Montalvo, E., Villaverde, V., Roldán, C., Murcia, S., & Badal, E. (2014). An approximation to the study of black pigments in Cova Remigia (Castellón, Spain). Technical and cultural assessments of the use of carbon-based black pigments in Spanish Levantine Rock Art. Journal of Archaeological Science, 52, 535-545. doi:10.1016/j.jas.2014.09.017Hernanz, A., Ruiz-López, J. F., Gavira-Vallejo, J. M., Martin, S., & Gavrilenko, E. (2010). Raman microscopy of prehistoric rock paintings from the Hoz de Vicente, Minglanilla, Cuenca, Spain. Journal of Raman Spectroscopy, 41(11), 1394-1399. doi:10.1002/jrs.2582Domingo, I., Villaverde, V., López-Montalvo, E., Lerma, J. L., & Cabrelles, M. (2013). Latest developments in rock art recording: towards an integral documentation of Levantine rock art sites combining 2D and 3D recording techniques. Journal of Archaeological Science, 40(4), 1879-1889. doi:10.1016/j.jas.2012.11.024Iturbe, A., Cachero, R., Cañal, D., & Martos, A. (2018). Digitalización de cuevas con arte paleolítico parietal de Bizkaia. Análisis científico y divulgación mediante nuevas técnicas de visualización. Virtual Archaeology Review, 9(18), 57. doi:10.4995/var.2018.7579Carrión-Ruiz, B., Blanco-Pons, S., & Lerma, J. L. (2016). DIGITAL IMAGE ANALYSIS OF THE VISIBLE REGION THROUGH SIMULATION OF ROCK ART PAINTINGS. 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Uso combinado de la fotografía digital nocturna y de la fotogrametría en los procesos de documentación de petroglifos: el caso de Alcázar de San Juan (Ciudad Real, España). Virtual Archaeology Review, 8(17), 64. doi:10.4995/var.2017.6820Molada-Tebar, A., Lerma, J. L., & Marqués-Mateu, Á. (2017). Camera characterization for improving color archaeological documentation. Color Research & Application, 43(1), 47-57. doi:10.1002/col.22152Del Hoyo-Meléndez, J. M., Lerma, J. L., López-Montalvo, E., & Villaverde, V. (2015). Documenting the light sensitivity of Spanish Levantine rock art paintings. ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences, II-5/W3, 53-59. doi:10.5194/isprsannals-ii-5-w3-53-2015Whitmore, P. M., Bailie, C., & Connors, S. A. (2000). Micro-fading tests to predict the result of exhibition: progress and prospects. Studies in Conservation, 45(sup1), 200-205. doi:10.1179/sic.2000.45.supplement-1.200Whitmore, P. M., Pan, X., & Bailie, C. (1999). Predicting the Fading of Objects: Identification of Fugitive Colorants through Direct Nondestructive Lightfastness Measurements. Journal of the American Institute for Conservation, 38(3), 395. doi:10.2307/3179999Ford, B. (2011). Non-destructive microfade testing at the National Museum of Australia. AICCM Bulletin, 32(1), 54-64. doi:10.1179/bac.2011.32.1.008Del Hoyo-Meléndez, J. M., & Mecklenburg, M. F. (2010). A survey on the light-fastness properties of organic-based Alaska Native artifacts. Journal of Cultural Heritage, 11(4), 493-499. doi:10.1016/j.culher.2010.01.004Conservation of Ancient Sites on the Silk Road 2010 The Getty Conservation Institute The Getty. Los Angeles JR Druzik Evaluating the light sensitivity of paints in selected wall paintings at the Mogao Grottoes: caves 217 98 and 85 457 463López-Montalvo, E., Roldán, C., Badal, E., Murcia-Mascarós, S., & Villaverde, V. (2017). Identification of plant cells in black pigments of prehistoric Spanish Levantine rock art by means of a multi-analytical approach. A new method for social identity materialization using chaîne opératoire. PLOS ONE, 12(2), e0172225. doi:10.1371/journal.pone.0172225Roldán, C., Murcia-Mascarós, S., Ferrero, J., Villaverde, V., López, E., Domingo, I., … Guillem, P. M. (2010). Application of field portable EDXRF spectrometry to analysis of pigments of Levantine rock art. X-Ray Spectrometry, 39(3), 243-250. doi:10.1002/xrs.1254Roldán García, C., Villaverde Bonilla, V., Ródenas Marín, I., & Murcia Mascarós, S. (2016). A Unique Collection of Palaeolithic Painted Portable Art: Characterization of Red and Yellow Pigments from the Parpalló Cave (Spain). PLOS ONE, 11(10), e0163565. doi:10.1371/journal.pone.0163565Łojewski, T., Thomas, J., Gołąb, R., Kawałko, J., & Łojewska, J. (2011). Note: Light ageing with simultaneous colorimetry via fibre optics reflection spectrometry. 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Microvertebrates preserved in mammal burrows from the Holocene of the Argentine Pampas: a taphonomic and paleoecological approach
Microvertebrates are a major component of many assemblages recovered from the Quaternary of the Argentine Pampas. The main goal of this paper is to analyse the taphonomic history of a Holocene microfossil bonebed, recovered from the infilling of a burrow. Evidences suggest the plains vizcacha Lagostomus maximus as the putative producer of the burrow. The assemblage includes individuals belonging to different taxa of mammals (marsupials and rodents) and reptiles (snakes). Taphonomic features suggest that the accumulation inside the burrow was related to flooding processes in the plain. The burrow was a natural trap that favoured the accumulation and preservation of remains corresponding to individuals from different sources. According to the taphonomic evidence, some individuals (Lagostomus maximus, Lestodelphys halli and Serpentes indet.) died inside the burrow, whereas others (Microcavia australis, Reithrodon auritus and Ctenomys sp.) died outside the burrow, and after a time of being exposed on the surface their remains were transported by surface run-offs into the burrow. The record of Lestodelphys halli and Serpentes indet. in the burrow produced by Lagostomus maximus could be related to a circumstantial use. Mammal burrows are a significant taphonomic mode for the late Cenozoic of the Argentine Pampas
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV
The performance of muon reconstruction, identification, and triggering in CMS
has been studied using 40 inverse picobarns of data collected in pp collisions
at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection
criteria covering a wide range of physics analysis needs have been examined.
For all considered selections, the efficiency to reconstruct and identify a
muon with a transverse momentum pT larger than a few GeV is above 95% over the
whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4,
while the probability to misidentify a hadron as a muon is well below 1%. The
efficiency to trigger on single muons with pT above a few GeV is higher than
90% over the full eta range, and typically substantially better. The overall
momentum scale is measured to a precision of 0.2% with muons from Z decays. The
transverse momentum resolution varies from 1% to 6% depending on pseudorapidity
for muons with pT below 100 GeV and, using cosmic rays, it is shown to be
better than 10% in the central region up to pT = 1 TeV. Observed distributions
of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO
Compressed representation of a partially defined integer function over multiple arguments
In OLAP (OnLine Analitical Processing) data are analysed in an n-dimensional cube. The cube may be represented as a partially defined function over n arguments. Considering that often the function is not defined everywhere, we ask: is there a known way of representing the function or the points in which it is defined, in a more compact manner than the trivial one
X-ray emission from the Sombrero galaxy: discrete sources
We present a study of discrete X-ray sources in and around the
bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival
Chandra observations with a total exposure of ~200 ks. With a detection limit
of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30
kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler
et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS
observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray
binaries (LMXBs). We quantify the differential luminosity functions (LFs) for
both the detected GC and field LMXBs, whose power-low indices (~1.1 for the
GC-LF and ~1.6 for field-LF) are consistent with previous studies for
elliptical galaxies. With precise sky positions of the GCs without a detected
X-ray source, we further quantify, through a fluctuation analysis, the GC LF at
fainter luminosities down to 1E35 erg/s. The derived index rules out a
faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent
findings in several elliptical galaxies and the bulge of M31. On the other
hand, the 2-6 keV unresolved emission places a tight constraint on the field
LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101
sources in the halo of Sombrero. The presence of these sources cannot be
interpreted as galactic LMXBs whose spatial distribution empirically follows
the starlight. Their number is also higher than the expected number of cosmic
AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray
surveys. We suggest that either the cosmic X-ray background is unusually high
in the direction of Sombrero, or a distinct population of X-ray sources is
present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres
Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV
The azimuthal anisotropy of charged particles in PbPb collisions at
nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS
detector at the LHC over an extended transverse momentum (pt) range up to
approximately 60 GeV. The data cover both the low-pt region associated with
hydrodynamic flow phenomena and the high-pt region where the anisotropies may
reflect the path-length dependence of parton energy loss in the created medium.
The anisotropy parameter (v2) of the particles is extracted by correlating
charged tracks with respect to the event-plane reconstructed by using the
energy deposited in forward-angle calorimeters. For the six bins of collision
centrality studied, spanning the range of 0-60% most-central events, the
observed v2 values are found to first increase with pt, reaching a maximum
around pt = 3 GeV, and then to gradually decrease to almost zero, with the
decline persisting up to at least pt = 40 GeV over the full centrality range
measured.Comment: Replaced with published version. Added journal reference and DO
Search for new physics with same-sign isolated dilepton events with jets and missing transverse energy
A search for new physics is performed in events with two same-sign isolated
leptons, hadronic jets, and missing transverse energy in the final state. The
analysis is based on a data sample corresponding to an integrated luminosity of
4.98 inverse femtobarns produced in pp collisions at a center-of-mass energy of
7 TeV collected by the CMS experiment at the LHC. This constitutes a factor of
140 increase in integrated luminosity over previously published results. The
observed yields agree with the standard model predictions and thus no evidence
for new physics is found. The observations are used to set upper limits on
possible new physics contributions and to constrain supersymmetric models. To
facilitate the interpretation of the data in a broader range of new physics
scenarios, information on the event selection, detector response, and
efficiencies is provided.Comment: Published in Physical Review Letter
Measurement of jet fragmentation into charged particles in pp and PbPb collisions at sqrt(s[NN]) = 2.76 TeV
Jet fragmentation in pp and PbPb collisions at a centre-of-mass energy of
2.76 TeV per nucleon pair was studied using data collected with the CMS
detector at the LHC. Fragmentation functions are constructed using
charged-particle tracks with transverse momenta pt > 4 GeV for dijet events
with a leading jet of pt > 100 GeV. The fragmentation functions in PbPb events
are compared to those in pp data as a function of collision centrality, as well
as dijet-pt imbalance. Special emphasis is placed on the most central PbPb
events including dijets with unbalanced momentum, indicative of energy loss of
the hard scattered parent partons. The fragmentation patterns for both the
leading and subleading jets in PbPb collisions agree with those seen in pp data
at 2.76 TeV. The results provide evidence that, despite the large parton energy
loss observed in PbPb collisions, the partition of the remaining momentum
within the jet cone into high-pt particles is not strongly modified in
comparison to that observed for jets in vacuum.Comment: Submitted to the Journal of High Energy Physic
Compositional analysis of bacterial communities in seawater, sediment, and sponges in the Misool coral reef system, Indonesia
Sponge species have been deemed high microbial abundance (HMA) or low microbial abundance (LMA) based on the composition and abundance of their microbial symbionts. In the present study, we evaluated the richness and composition of bacterial communities associated with one HMA sponge (Xestospongia testudinaria; Demospongiae: Haplosclerida: Petrosiidae), one LMA sponge (Stylissa carteri; Demospongiae: Scopalinida - Scopalinidae), and one sponge with a hitherto unknown microbial community (Aaptos suberitoides; Demospongiae: Suberitida: Suberitidae) inhabiting the Misool coral reef system in the West Papua province of Indonesia. The bacterial communities of these sponge species were also compared with seawater and sediment bacterial communities from the same coastal coral reef habitat. Using a 16S rRNA gene barcoded pyrosequencing approach, we showed that the most abundant phylum overall was Proteobacteria. The biotope (sponge species, sediment or seawater) explained almost 84% of the variation in bacterial composition with highly significant differences in composition among biotopes and a clear separation between bacterial communities from seawater and S. carteri; X. testudinaria and A. suberitoides and sediment. The Chloroflexi classes SAR202 and Anaerolineae were most abundant in A. suberitoides and X. testudinaria and both of these species shared several OTUs that were largely absent in the remaining biotopes. This suggests that A. suberitoides is a HMA sponge. Although similar, the bacterial communities of S. carteri and seawater were compositionally distinct. These results confirm compositional differences between sponge and non-sponge biotopes and between HMA and LMA sponges.publishe
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