91 research outputs found
A Unique Human-Fox Burial from a Pre-Natufian Cemetery in the Levant (Jordan)
New human burials from northern Jordan provide important insights into the appearance of cemeteries and the nature of human-animal relationships within mortuary contexts during the Epipalaeolithic period (c. 23,000â11,600 cal BP) in the Levant, reinforcing a socio-ideological relationship that goes beyond predator-prey. Previous work suggests that archaeological features indicative of social complexity occur suddenly during the latest Epipalaeolithic phase, the Natufian (c. 14,500â11,600 cal BP). These features include sedentism, cemeteries, architecture, food production, including animal domestication, and burials with elaborate mortuary treatments. Our findings from the pre-Natufian (Middle Epipalaeolithic) cemetery of âUyun al-Hammam demonstrate that joint human-animal mortuary practices appear earlier in the Epipalaeolithic. We describe the earliest human-fox burial in the Near East, where the remains of dogs have been found associated with human burials at a number of Natufian sites. This is the first time that a fox has been documented in association with human interments pre-dating the Natufian and with a particular suite of grave goods. Analysis of the human and animal bones and their associated artefacts provides critical data on the nature and timing of these newly-developing relationships between people and animals prior to the appearance of domesticated dogs in the Natufian
Photosynthesis by six portuguese maize cultivars during drought stress and recovery
Photosynthesis, chlorophyll fluorescence and leaf water parameters were measured in six Portuguese maize (Zea mays L.) cultivars during and following a period of drought stress. The leaf relative water content (RWC) responded differently among cultivars but, except for cultivar PB369, recovered close to initial values after watering was restored.
Photosynthetic rate and stomatal conductance decreased with drought but more slowly in cultivars PB269 and PB260 than in cultivars AD3R, PB64, PB304 and PB369. Water use efficiency (WUE) decreased during the water stress treatment although with cultivar PB260 the decrease was marked only when the RWC fell below 40%. Recovery of WUE was seen with all cultivars except PB369. The maximum quantum efficiency of photosystem II, the
photochemical quenching coefficient, the electron transport rate in PSII and the estimated functional plastoquinone pool
tended to decrease with drought, while the non -photochemical quenching coefficient increased. The parameters estimated from chlorophyll fluorescence did not recover in PB369, during re - watering. The results show that PB260 and PB269 were the most tolerant and PB369 was the least tolerant cultivars to water stress. The variation found amongst
the cultivars tested suggests the existence of valuable genetic resources for crop improvement in relation to drought tolerance
Adolescent Brain Development and the Risk for Alcohol and Other Drug Problems
Dynamic changes in neurochemistry, fiber architecture, and tissue composition occur in the adolescent brain. The course of these maturational processes is being charted with greater specificity, owing to advances in neuroimaging and indicate grey matter volume reductions and protracted development of white matter in regions known to support complex cognition and behavior. Though fronto-subcortical circuitry development is notable during adolescence, asynchronous maturation of prefrontal and limbic systems may render youth more vulnerable to risky behaviors such as substance use. Indeed, binge-pattern alcohol consumption and comorbid marijuana use are common among adolescents, and are associated with neural consequences. This review summarizes the unique characteristics of adolescent brain development, particularly aspects that predispose individuals to reward seeking and risky choices during this phase of life, and discusses the influence of substance use on neuromaturation. Together, findings in this arena underscore the importance of refined research and programming efforts in adolescent health and interventional needs
Search for Standard Model Higgs Boson Production in Association with a W Boson using a Neural Network
Submitted to Phys. Rev. DWe present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector that correspond to an integrated luminosity of approximately 1.9 inverse fb. We select events consistent with a signature of a single charged lepton, missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method, a jet probability tagging method, and a neural network filter. We use kinematic information in an artificial neural network to improve discrimination between signal and background compared to previous analyses. The observed number of events and the neural network output distributions are consistent with the standard model background expectations, and we set 95% confidence level upper limits on the production cross section times branching fraction ranging from 1.2 to 1.1 pb or 7.5 to 102 times the standard model expectation for Higgs boson masses from 110 to $150 GeV/c^2, respectively.We present a search for standard model Higgs boson production in association with a W boson in proton-antiproton collisions (ppÌ
âW±HââÎœbbÌ
) at a center of mass energy of 1.96 TeV. The search employs data collected with the CDF II detector that correspond to an integrated luminosity of approximately 1.9ââfb-1. We select events consistent with a signature of a single charged lepton (e±/Ό±), missing transverse energy, and two jets. Jets corresponding to bottom quarks are identified with a secondary vertex tagging method, a jet probability tagging method, and a neural network filter. We use kinematic information in an artificial neural network to improve discrimination between signal and background compared to previous analyses. The observed number of events and the neural network output distributions are consistent with the standard model background expectations, and we set 95% confidence level upper limits on the production cross section times branching fraction ranging from 1.2 to 1.1 pb or 7.5 to 102 times the standard model expectation for Higgs boson masses from 110 to 150ââGeV/c2, respectively.Peer reviewe
Measurement of b hadron lifetimes in exclusive decays containing a J/psi in p-pbar collisions at sqrt(s)=1.96TeV
We report on a measurement of -hadron lifetimes in the fully reconstructed
decay modes B^+ -->J/Psi K+, B^0 --> J/Psi K*, B^0 --> J/Psi Ks, and Lambda_b
--> J/Psi Lambda using data corresponding to an integrated luminosity of 4.3
, collected by the CDF II detector at the Fermilab Tevatron. The
measured lifetimes are B^+ = , B^0 = and Lambda_b = . The lifetime ratios are B^+/B^0 = and Lambda_b/B^0 = . These are the most precise determinations
of these quantities from a single experiment.Comment: revised version. accepted for PRL publicatio
Measurement of ZZ production in leptonic final states at {\surd}s of 1.96 TeV at CDF
In this paper we present a precise measurement of the total ZZ production
cross section in pp collisions at {\surd}s= 1.96 TeV, using data collected with
the CDF II detector corresponding to an integrated luminosity of approximately
6 fb-1. The result is obtained by combining separate measurements in the
four-charged (lll'l'), and two-charged-lepton and two-neutral-lepton (llvv)
decay modes of the Z. The combined measured cross section for pp {\to} ZZ is
1.64^(+0.44)_(-0.38) pb. This is the most precise measurement of the ZZ
production cross section in 1.96 TeV pp collisions to date.Comment: submitted to Phys. Rev. Let
Observation of exclusive charmonium production and gamma+gamma to mu+mu- in p+pbar collisions at sqrt{s} = 1.96 TeV
7 pages, 3 figures, 1 table. Version accepted for Phys.Rev.Lett. Phys.Rev.Lett. (to be published)We have observed the reactions p+pbar --> p+X+pbar, with X being a centrally produced J/psi, psi(2S) or chi_c0, and gamma+gamma --> mu+mu-, in proton- antiproton collisions at sqrt{s} = 1.96 TeV using the Run II Collider Detector at Fermilab. The event signature requires two oppositely charged muons, each with pseudorapidity |eta| mu+mu-. Events with a J/psi and an associated photon candidate are consistent with exclusive chi_c0 production through double pomeron exchange. The exclusive vector meson production is as expected for elastic photo- production, gamma+p --> J/psi(psi(2S)) + p, which is observed here for the first time in hadron-hadron collisions. The cross sections ds/dy(y=0) for p + pbar --> p + X + pbar with X = J/psi, psi(2S) orchi_c0 are 3.92+/-0.62 nb, 0.53+/-0.14 nb, and 75+/-14 nb respectively. The cross section for the continuum, with |eta(mu+/-)|In CDF we have observed the reactions p+pÌ
âp+X+pÌ
, with X being a centrally produced J/Ï, Ï(2S), or Ïc0, and γγâÎŒ+ÎŒ- in ppÌ
collisions at âs=1.96ââTeV. The event signature requires two oppositely charged central muons, and either no other particles or one additional photon detected. Exclusive vector meson production is as expected for elastic photoproduction, Îł+pâJ/Ï(Ï(2S))+p, observed here for the first time in hadron-hadron collisions. We also observe exclusive Ïc0âJ/Ï+Îł. The cross sections dÏ/dy|y=0 for J/Ï, Ï(2S), and Ïc0 are 3.92±0.25(stat)±0.52(syst)âânb, 0.53±0.09(stat)±0.10(syst)âânb, and 76±10(stat)±10(syst)âânb, respectively, and the continuum is consistent with QED. We put an upper limit on the cross section for Odderon exchange in exclusive J/Ï production.Peer reviewe
Search for the Production of Narrow tb Resonances in 1.9 fb-1 of ppbar Collisions at sqrt(s) = 1.96 TeV
We present new limits on resonant tb production in proton-antiproton collisions at 1.96 TeV, using 1.9 fb^-1 of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a candidate mass in events with a lepton, neutrino candidate, and two or three jets, and search for anomalous tb production as modeled by W'->tb. We set a new limit on a right-handed W' with standard model-like coupling, excluding any mass below 800 GeV at 95% C.L. The cross-section for any narrow, resonant tb production between 750 and 950 GeV is found to be less than 0.28 pb at 95% C.L. We also present an exclusion of the W' coupling strength versus W' mass over the range 300 to 950 GeV.We present new limits on resonant tbÌ
production in ppÌ
collisions at âs=1.96ââTeV, using 1.9ââfb-1 of data recorded with the CDF II detector at the Fermilab Tevatron. We reconstruct a candidate tbÌ
mass in events with a lepton, neutrino candidate, and two or three jets, and search for anomalous tbÌ
production as modeled by WâČâtbÌ
. We set a new limit on a right-handed WâČ with standard model-like coupling, excluding any mass below 800ââGeV/c2 at 95% C.L. The cross section for any narrow, resonant tbÌ
production between 750 and 950ââGeV/c2 is found to be less than 0.28 pb at 95% C.L. We also present an exclusion of the WâČ coupling strength versus WâČ mass over the range 300â950ââGeV/c2.Peer reviewe
Recommended from our members
Search for neutral MSSM Higgs bosons decaying to a pair of tau leptons in pp collisions
Peer reviewe
Study of hadronic event-shape variables in multijet final states in pp collisions at âs=7 TeV
Peer reviewe
- âŠ