Hunter-gatherer mobility and territories in the dunefields of center Argentina

The distribution of certain rocks in the landscape allows us to reconstruct diverse aspects of past hunter-gatherer behavior. In this work, we evaluate the mobility patterns employed by these groups and the presence or absence of boundaries in the Aeolian system of the center of Argentina. To accomplish this objective, we consider two types of evidence: 1) raw material frequencies and distributions in three areas of this Aeolian System and 2) presence and frequency of knapping stones from Tandilia sources. We construct a fall-off curve that is based on the relationship between the frequency of an item and the distance to the source of supply. The characteristics of each area yielded the human groups that inhabited delineate different modes of exploitation of the rocks. The fall-off curve documents a steep drop-off between 300 and 350 km from the Tandilia source and the spatial analysis indicates that within this distance the source probably represents the threshold of direct access to the quarries. Tandilia stone-tools seem to systematically supply a relatively wide area of the Central Pampean Dunefields of the Pampa grasslands, through varied processes, but they arrive at very low frequencies over great distances. The presence of Tandilia rocks in the Western Pampean Dunefields and Western Pampas Sand Mantles and Dunefields indicates social interaction between human groups that shared some common technological knowledge. The presence of stones in the Central Pampean Dunefields coming from the xerophytic woodland of the Dry Pampas can be related with contacts and exchanges among the hunter-gatherer group that occupied different territories

Provenance, manufacture and use of lithic materials at Laguna Cabeza de Buey 2 site (Central Pampa grasslands, Buenos Aires) during the Middle and Late Holocene

En este trabajo se describen los resultados generados a través del estudio tecnomorfológico y funcional de base microscópica de los materiales líticos del sector excavado del sitio Laguna Cabeza de Buey 2. Se integra el conocimiento acerca de las estrategias de obtención, producción y uso de dichos recursos por parte de los grupos cazadores-recolectores bajo dos condiciones paleoambientales diferentes. Durante el Holoceno medio se identifica un ambiente semiárido con la presencia de una laguna somera de agua salada que posibilitó ocupaciones humanas efímeras. Las características tecnológicas, la baja diversidad artefactual y la escasa variabilidad de materiales procesados con los instrumentos, principalmente madera y hueso, sustentan la presencia de sitios de actividades restringidas vinculados con un patrón de alta movilidad. En cambio, para la parte final del Holoceno tardío, el modelo paleoclimático señala condiciones de humedad similares a las actuales, con una vegetación de pastizales más abundante y el establecimiento de un cuerpo semipermanente de agua dulce. En este marco, se registra una ocupación con un mayor grado de intensidad que se sustenta en la mayor cantidad y diversidad artefactual, la amplia gama de sustancias procesadas con los instrumentos (piel, madera, hueso y vegetales no leñosos) y la presencia de cerámica.In this article, we describe the results obtained from the techno-morphological and micro-wear analysis of lithic materials from the excavated sector of Laguna Cabeza de Buey 2 site. Here, we assess data concerning the acquisition, production, and use strategies of these resources, as developed by hunter-gatherer groups under two different palaeoenvironmental conditions. During the Middle Holocene, we identified a semi-arid environment with the presence of a small, brackish and shallow body of water that permitted ephemeral human occupations. The technological characteristics, the low diversity of typological groups, and types of materials processed by the tools —mainly wood and bone— lends support to the presence of temporary human occupations linked to a high mobility pattern. On the other hand, towards the end of the Late Holocene, the palaeoclimatic model indicates humid conditions similar to the present-day, with a more stable landscape —dunes fixed with grassland vegetation— and the presence of a permanent body of water. In this context, there was a much more intense occupation, reflected in the greater quantity and diversity of tools, the wide range of materials processed with them, including skin, wood, bone and non-woody vegetables, as well as the appearance of pottery

El Holoceno Medio en valles fluviales del sudeste pampeano: ¿Escasez de sitios o de unidades portadoras? Una perspectiva geoarqueológica

En este trabajo se presenta el estudio estratigráfico y cronológico de siete sitios arqueológicos localizados en las cuencas de los arroyos Cortaderas, Cristiano Muerto y Tapalqué (provincia de Buenos Aires, Argentina). El objetivo es evaluar si la ausencia y/o baja representación de unidades estratigráficas del Holoceno medio en estos cursos de bajo orden está condicionando la señal arqueológica en el sudeste pampeano. Los resultados indican que los depósitos fluviales correspondientes a este período resultan escasos y que, con frecuencia, existen discordancias erosivas entre las unidades datadas en el Holoceno tardío y aquellas correspondientes al Pleistoceno tardío u Holoceno temprano sobre las que apoyan. Este hecho también se observa en sitios localizados en otros cursos fluviales de bajo orden del sudeste pampeano. En consecuencia, la baja señal arqueológica del Holoceno medio en muchos valles puede deberse, al menos en parte, a este sesgo estratigráfico. Adicionalmente, los suelos/paleosuelos desarrollados en estas secuencias fluviales concentraron la evidencia cultural, lo cual genera una imagen de pulsos de ocupación humana y de hiatos arqueológicos que podría considerarse principalmente un resultado de la dinámica fluvial. Tal panorama estratigráfico en los cursos de bajo orden no sólo es válido para la región analizada sino que posee implicaciones para secuencias fluviales de numerosos valles en Argentina

Reconstructing the Deep Population History of Central and South America

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least 9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America. One affected the Central Andes by 4,200 years ago, while the other explains an affinity between the oldest North American genome associated with the Clovis culture and the oldest Central and South Americans from Chile, Brazil, and Belize. However, this was not the primary source for later South Americans, as the other ancient individuals derive from lineages without specific affinity to the Clovis-associated genome, suggesting a population replacement that began at least 9,000 years ago and was followed by substantial population continuity in multiple regions

Alignment of the CMS silicon tracker during commissioning with cosmic rays

This is the Pre-print version of the Article. The official published version of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe CMS silicon tracker, consisting of 1440 silicon pixel and 15 148 silicon strip detector modules, has been aligned using more than three million cosmic ray charged particles, with additional information from optical surveys. The positions of the modules were determined with respect to cosmic ray trajectories to an average precision of 3–4 microns RMS in the barrel and 3–14 microns RMS in the endcap in the most sensitive coordinate. The results have been validated by several studies, including laser beam cross-checks, track fit self-consistency, track residuals in overlapping module regions, and track parameter resolution, and are compared with predictions obtained from simulation. Correlated systematic effects have been investigated. The track parameter resolutions obtained with this alignment are close to the design performance.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

Commissioning and performance of the CMS pixel tracker with cosmic ray muons

This is the Pre-print version of the Article. The official published verion of the Paper can be accessed from the link below - Copyright @ 2010 IOPThe pixel detector of the Compact Muon Solenoid experiment consists of three barrel layers and two disks for each endcap. The detector was installed in summer 2008, commissioned with charge injections, and operated in the 3.8 T magnetic field during cosmic ray data taking. This paper reports on the first running experience and presents results on the pixel tracker performance, which are found to be in line with the design specifications of this detector. The transverse impact parameter resolution measured in a sample of high momentum muons is 18 microns.This work is supported by FMSR (Austria); FNRS and FWO (Belgium); CNPq, CAPES, FAPERJ, and FAPESP (Brazil); MES (Bulgaria); CERN; CAS, MoST, and NSFC (China); COLCIENCIAS (Colombia); MSES (Croatia); RPF (Cyprus); Academy of Sciences and NICPB (Estonia); Academy of Finland, ME, and HIP (Finland); CEA and CNRS/IN2P3 (France); BMBF, DFG, and HGF (Germany); GSRT (Greece); OTKA and NKTH (Hungary); DAE and DST (India); IPM (Iran); SFI (Ireland); INFN (Italy); NRF (Korea); LAS (Lithuania); CINVESTAV, CONACYT, SEP, and UASLP-FAI (Mexico); PAEC (Pakistan); SCSR (Poland); FCT (Portugal); JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); MST and MAE (Russia); MSTDS (Serbia); MICINN and CPAN (Spain); Swiss Funding Agencies (Switzerland); NSC (Taipei); TUBITAK and TAEK (Turkey); STFC (United Kingdom); DOE and NSF (USA)

Performance of the CMS drift-tube chamber local trigger with cosmic rays

The performance of the Local Trigger based on the drift-tube system of the CMS experiment has been studied using muons from cosmic ray events collected during the commissioning of the detector in 2008. The properties of the system are extensively tested and compared with the simulation. The effect of the random arrival time of the cosmic rays on the trigger performance is reported, and the results are compared with the design expectations for proton-proton collisions and with previous measurements obtained with muon beams

Search for long-lived particles produced in association with a Z boson in proton-proton collisions at s \sqrt{s} = 13 TeV

A search for long-lived particles (LLPs) produced in association with a Z boson is presented. The study is performed using data from proton-proton collisions with a center-of-mass energy of 13 TeV recorded by the CMS experiment during 2016–2018, corresponding to an integrated luminosity of 117 fb−1. The LLPs are assumed to decay to a pair of standard model quarks that are identified as displaced jets within the CMS tracker system. Triggers and selections based on Z boson decays to electron or muon pairs improve the sensitivity to light LLPs (down to 15 GeV). This search provides sensitivity to beyond the standard model scenarios which predict LLPs produced in association with a Z boson. In particular, the results are interpreted in the context of exotic decays of the Higgs boson to a pair of scalar LLPs (H → SS). The Higgs boson decay branching fraction is constrained to values less than 6% for proper decay lengths of 10–100 mm and for LLP masses between 40 and 55 GeV. In the case of low-mass (≈ 15 GeV) scalar particles that subsequently decay to a pair of b quarks, the search is sensitive to branching fractions B(H → SS) < 20% for proper decay lengths of 10–50 mm. The use of associated production with a Z boson increases the sensitivity to low-mass LLPs of this analysis with respect to gluon fusion searches. In the case of 15 GeV scalar LLPs, the improvement corresponds to a factor of 2 at a proper decay length of 30 mm

Probing effective field theory operators in the associated production of top quarks with a Z boson in multilepton final states at s \sqrt{s} = 13 TeV

A search for new top quark interactions is performed within the framework of an effective field theory using the associated production of either one or two top quarks with a Z boson in multilepton final states. The data sample corresponds to an integrated luminosity of 138 fb−1 of proton-proton collisions at s√ = 13 TeV collected by the CMS experiment at the LHC. Five dimension-six operators modifying the electroweak interactions of the top quark are considered. Novel machine-learning techniques are used to enhance the sensitivity to effects arising from these operators. Distributions used for the signal extraction are parameterized in terms of Wilson coefficients describing the interaction strengths of the operators. All five Wilson coefficients are simultaneously fit to data and 95% confidence level intervals are computed. All results are consistent with the SM expectations

Analysis of the CP structure of the Yukawa coupling between the Higgs boson and τ leptons in proton-proton collisions at s\sqrt{s} = 13 TeV

The first measurement of the CP structure of the Yukawa coupling between the Higgs boson and τ leptons is presented. The measurement is based on data collected in proton-proton collisions at $\sqrt{s}$ = 13 TeV by the CMS detector at the LHC, corresponding to an integrated luminosity of 137 fb$^{-1}$. The analysis uses the angular correlation between the decay planes of τ leptons produced in Higgs boson decays. The effective mixing angle between CP-even and CP-odd τ Yukawa couplings is found to be −1 ± 19°, compared to an expected value of 0 ± 21° at the 68.3% confidence level. The data disfavour the pure CP-odd scenario at 3.0 standard deviations. The results are compatible with predictions for the standard model Higgs boson