77 research outputs found
Influence de l'environnement familial sur les comportements agressifs d'enfants d'ùge préscolaire
L'apport du réaffûtage à la variabilité morphométrique des pointes de projectile aurignaciennes en bois de cervidé
Ce projet combine lâarchĂ©ologie expĂ©rimentale, lâanalyse morphomĂ©trique et la comparaison des rĂ©sultats Ă lâassemblage archĂ©ologique de lâAbri Cellier (Dordogne, France) (N = 12) dans le but de quantifier lâapport du rĂ©affĂ»tage Ă la variabilitĂ© des formes et des dimensions des pointes de projectile aurignaciennes en bois de cervidĂ©. La relecture morphofonctionnelle de la sĂ©rie expĂ©rimentale de Knecht (N = 79) couplĂ©e Ă une reproduction expĂ©rimentale rĂ©cente (N = 9) dĂ©montre que la nature des dommages infligĂ©s au fĂ»t des pointes dĂ©pend (1) de la force du tir, (2) de la nature de la cible impactĂ©e et, (3) des propriĂ©tĂ©s biomĂ©caniques du matĂ©riau employĂ©. Pour sa part, le rĂ©affĂ»tage dĂ©pend (1) de lâexpĂ©rience du rĂ©affĂ»teur et, (2) de la sĂ©quence technique employĂ©e. Ce comportement est standardisĂ© et demeure indĂ©pendant du type de pointe de mĂȘme que du type de dommage du fĂ»t. Les changements morphomĂ©triques associĂ©s Ă ce comportement se rĂ©sument (1) Ă un dĂ©placement progressif de lâĂ©paule de la base vers le fĂ»t de la pointe, (2) Ă une tendance Ă lâaccroissement de lâangle du fĂ»t et, (3) Ă une localisation des traces de rĂ©affĂ»tage sur le tiers distal de la partie distale de la pointe. Puisque lâutilisation et le rĂ©affĂ»tage sont deux processus impossible Ă dĂ©partager sur les artefacts, nous proposons lâadoption dâune mesure, le ratio proximo-distal (RP/D) afin de traduire lâintensitĂ© de ces processus convergents et faciliter la comparaison entre les assemblages archĂ©ologiques.This project combines experimental archaeology and morphometric analysis with a comparison with the archaeological assemblage from Abri Cellier (Dordogne, France) (N = 12) to quantify the contribution of resharpening to morphometric variability of Aurignacian projectile points made of antler. A morpho-functional re-analysis was performed on the experimental series produced by Knecht (N = 79), and combined with a recent experiment (N = 9) which showed that tip damage depends on (1) the projectile velocity, (2) the nature of the impacted target and, (3) the raw materialâs biomechanical properties. On the other hand, resharpening depends on (1) the curatorâs experience and, (2) the employed technical sequence. Also, resharpening is considered a standardized behaviour that remains independent of the point or tip damage type. Morphometric changes incurred by this behaviour can be summarized by (1) a gradual shift of the pointâs shoulder from the base to the tip of the point, (2) a tendency of the tip to become more obtuse, and (3) a concentration of the curation stigmata at the distal third of the tip. Since use and resharpening are two processes that canât be distinguished metrically on archaeological specimens, we propose a new metric the Proximo-Distal Ratio (RP/D), which translates the intensity of these two converging processes and allows inter-assemblage comparison
A 115,000-year-old expedient bone technology at Lingjing, Henan, China
Activities attested since at least 2.6 Myr, such as stone knapping, marrow extraction, and woodworking may have allowed early hominins to recognize the technological potential of discarded skeletal remains and equipped them with a transferable skillset fit for the marginal modification and utilization of bone flakes. Identifying precisely when and where expedient bone tools were used in prehistory nonetheless remains a challenging task owing to the multiple natural and anthropogenic processes that can mimic deliberately knapped bones. Here, we compare a large sample of the faunal remains from Lingjing, a 115 ka-old site from China which has yielded important hominin remains and rich faunal and lithic assemblages, with bone fragments produced by experimentally fracturing Equus caballus long bones. Our results provide a set of qualitative and quantitative criteria that can help zooarchaeologists and bone technologists distinguish faunal remains with intentional flake removal scars from those resulting from carcass processing activities. Experimental data shows marrow extraction seldom generates diaphyseal fragments bearing more than six flake scars arranged contiguously or in interspersed series. Long bone fragments presenting such characteristics can, therefore, be interpreted as being purposefully knapped to be used as expediency tools. The identification, based on the above experimental criteria, of 56 bone tools in the Lingjing faunal assemblage is consistent with the smaller size of the lithics found in the same layer. The continuity gradient observed in the size of lithics and knapped bones suggests the latter were used for tasks in which the former were less or not effective.publishedVersio
Zhoukoudian Upper Cave personal ornaments and ochre: Rediscovery and reevaluation
Under embargo until: 2022-11-24Personal ornaments have become a key cultural proxy to investigate cognitive evolution, modern human dispersal, and population dynamics. Here, we reassess personal ornaments found at Zhoukoudian Upper Cave and compare them with those from other Late Paleolithic Northern Chinese sites. We reappraise the information provided by Pei Wen Chung on Upper Cave personal ornaments lost during World War II and analyze casts of 17 of them, along with two unpublished objects displayed at the Zhoukoudian Site Museum and three original perforated teeth rediscovered at the Zhoukoudian Site Museum. We apply archeozoological, technological and use-wear analyses to document variation in ornamental practices and their change throughout the site stratigraphy. Badger, fox, red deer, sika deer, marten, and tiger teeth as well as carp bone, bird bone, Anadara shell, limestone beads, and perforated pebble appear to have been the preferred objects used as ornaments by Upper Cave visitors. Multivariate analysis of technological data highlights a correspondence between cultural layers and perforation techniques, with radial incising being typical of layer L2 and bidirectional incising of L4. The three rediscovered badger canines display features suggesting they were sewed on clothing rather than suspended from necklaces or bracelets. Elemental scanning electron microscopy coupled with energy dispersive X-ray spectromety and mineralogical (Ό-Raman) analyses of red residues adhering to the rediscovered teeth indicate these objects were originally coated with ochre and identify variations that match differences in technology. The two ornaments exhibited at the Zhoukoudian Site Museum are ancient teeth that were recently perforated and should be excluded from the Upper Cave assemblage. A seriation of Late Paleolithic ornaments found at Northern Chinese sites identifies a clear-cut difference in preferred ornament types between western and eastern sites, interpreted as reflecting two long-lasting traditions in garment symbolic codes.acceptedVersio
A 39,600-year-old leather punch board from Canyars, GavĂ , Spain
Puncture alignments are found on Palaeolithic carvings, pendants, and other fully shaped These marks were interpreted as abstract decorations, system of notations, and features and animal depictions. Here, we create an experimental framework for the analysis and human-made punctures and apply it to a highly intriguing, punctured bone fragment found at Early Upper Palaeolithic coastal site from Catalonia, Spain. Changes of tool and variation in the and orientation of punctures are consistent with the interpretation of this object as the earliest- work punch board recording six episodes of hide pricking, one of which was to produce a linear results indicate that Aurignacian hunters-gatherers used this technology to produce leather tailored clothes well before the introduction of bone eyed needles in Europe 15,000 years later
Technological and functional analysis of 80â60Â ka bone wedges from Sibudu (KwaZulu-Natal, South Africa)
Fully shaped, morphologically standardized bone tools are generally considered reliable indicators of the emergence of modern behavior. We report the discovery of 23 double-beveled bone tools fromâ~â80,000â60,000-year-old archaeological layers at Sibudu Cave in KwaZulu-Natal, South Africa. We analyzed the texture of use-wear on the archaeological bone tools, and on bone tool replicas experimentally used in debarking trees, processing rabbit pelts with and without an ochre compound, digging in sediment in and outside a cave, and on ethnographic artefacts. Debarking trees and digging in humus-rich soil produce use-wear patterns closely matching those observed on most Sibudu tools. This tool type is associated with three different Middle Stone Age cultural traditions at Sibudu that span 20,000 years, yet they are absent at contemporaneous sites. Our results support a scenario in which some southern African early modern human groups developed and locally maintained specific, highly standardized cultural traits while sharing others at a sub-continental scale. We demonstrate that technological and texture analyses are effective means by which to infer past behaviors and assess the significance of prehistoric cultural innovations.publishedVersio
Technological and functional analysis of 80â60 ka bone wedges from Sibudu (KwaZulu-Natal, South Africa)
Fully shaped, morphologically standardized bone tools are generally considered reliable indicators of the emergence of modern behavior. We report the discovery of 23 double-beveled bone tools fromâ~â80,000â60,000-year-old archaeological layers at Sibudu Cave in KwaZulu-Natal, South Africa. We analyzed the texture of use-wear on the archaeological bone tools, and on bone tool replicas experimentally used in debarking trees, processing rabbit pelts with and without an ochre compound, digging in sediment in and outside a cave, and on ethnographic artefacts. Debarking trees and digging in humus-rich soil produce use-wear patterns closely matching those observed on most Sibudu tools. This tool type is associated with three different Middle Stone Age cultural traditions at Sibudu that span 20,000 years, yet they are absent at contemporaneous sites. Our results support a scenario in which some southern African early modern human groups developed and locally maintained specific, highly standardized cultural traits while sharing others at a sub-continental scale. We demonstrate that technological and texture analyses are effective means by which to infer past behaviors and assess the significance of prehistoric cultural innovations
APERO: A PipelinE to Reduce Observations -- Demonstration with SPIRou
With the maturation of near-infrared high-resolution spectroscopy, especially
when used for precision radial velocity, data reduction has faced unprecedented
challenges in terms of how one goes from raw data to calibrated, extracted, and
corrected data with required precisions of thousandths of a pixel. Here we
present APERO (A PipelinE to Reduce Observations), specifically focused on
SPIRou, the near-infrared spectropolarimeter on the Canada--France--Hawaii
Telescope (SPectropolarim\`etre InfraROUge, CFHT). In this paper, we give an
overview of APERO and detail the reduction procedure for SPIRou. APERO delivers
telluric-corrected 2D and 1D spectra as well as polarimetry products. APERO
enables precise stable radial velocity measurements on sky (via the LBL
algorithm), good to at least ~2 m/s over the current 5-year lifetime of SPIRou.Comment: Accepted for publication in PASP. 55 pages, 29 figures, 10 pages of
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Higher maternal leptin levels at second trimester are associated with subsequent greater gestational weight gain in late pregnancy
Background: Excessive gestational weight gain (GWG) is associated with adverse pregnancy outcomes. In non-pregnant populations, low leptin levels stimulate positive energy balance. In pregnancy, both the placenta and adipose tissue contribute to circulating leptin levels. We tested whether maternal leptin levels are associated with subsequent GWG and whether this association varies depending on stage of pregnancy and on maternal body mass index (BMI). Methods: This prospective cohort study included 675 pregnant women followed from 1st trimester until delivery. We collected anthropometric measurements, blood samples at 1st and 2nd trimester, and clinical data until delivery. Maternal leptin was measured by ELISA (Luminex technology). We classified women by BMI measured at 1st trimester: BMI < 25 kg/m2 = normal weight; 25 †BMI < 30 kg/m2 = overweight; and BMI â„ 30 kg/m2 = obese. Results: Women gained a mean of 6.7 ± 3.0 kg between 1st and 2nd trimester (mid pregnancy GWG) and 5.6 ± 2.5 kg between 2nd and the end of 3rd trimester (late pregnancy GWG). Higher 1st trimester leptin levels were associated with lower mid pregnancy GWG, but the association was no longer significant after adjusting for % body fat (%BF; ÎČ = 0.38 kg per log-leptin; SE = 0.52; P = 0.46). Higher 2nd trimester leptin levels were associated with greater late pregnancy GWG and this association remained significant after adjustment for BMI (ÎČ = 2.35; SE = 0.41; P < 0.0001) or %BF (ÎČ = 2.01; SE = 0.42; P < 0.0001). In BMI stratified analyses, higher 2nd trimester leptin levels were associated with greater late pregnancy GWG in normal weight women (ÎČ = 1.33; SE = 0.42; P = 0.002), and this association was stronger in overweight women (ÎČ = 2.85; SE = 0.94; P = 0.003 â P for interaction = 0.05). Conclusions: Our results suggest that leptin may regulate weight gain differentially at 1st versus 2nd trimester of pregnancy: at 2nd trimester, higher leptin levels were associated with greater subsequent weight gain â the opposite of its physiologic regulation in non-pregnancy â and this association was stronger in overweight women. We suspect the existence of a feed-forward signal from leptin in second half of pregnancy, stimulating a positive energy balance and leading to greater weight gain. Electronic supplementary material The online version of this article (doi:10.1186/s12884-016-0842-y) contains supplementary material, which is available to authorized users
A massive hot Jupiter orbiting a metal-rich early-M star discovered in the TESS full frame images
Observations and statistical studies have shown that giant planets are rare
around M dwarfs compared with Sun-like stars. The formation mechanism of these
extreme systems remains under debate for decades. With the help of the TESS
mission and ground based follow-up observations, we report the discovery of
TOI-4201b, the most massive and densest hot Jupiter around an M dwarf known so
far with a radius of and a mass of ,
about 5 times heavier than most other giant planets around M dwarfs. It also
has the highest planet-to-star mass ratio () among such
systems. The host star is an early-M dwarf with a mass of $0.61\pm0.02\
M_{\odot}0.63\pm0.02\ R_{\odot}0.52\pm 0.08$ dex). However, interior
structure modeling suggests that its planet TOI-4201b is metal-poor, which
challenges the classical core-accretion correlation of stellar-planet
metallicity, unless the planet is inflated by additional energy sources.
Building on the detection of this planet, we compare the stellar metallicity
distribution of four planetary groups: hot/warm Jupiters around G/M dwarfs. We
find that hot/warm Jupiters show a similar metallicity dependence around G-type
stars. For M dwarf host stars, the occurrence of hot Jupiters shows a much
stronger correlation with iron abundance, while warm Jupiters display a weaker
preference, indicating possible different formation histories.Comment: 21 pages, 11 figures, 4 tables, submitted to A
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