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Correlations in the hadron distributions produced in relativistic Au+Au collisions are studied in the discrete wavelet expansion method. The analysis is performed in the space of pseudorapidity (| eta | <= 1) and azimuth(full 2 pi ) in bins of transverse momentum (pt) from 0.14 <= pt <= 2.1GeV/c. In peripheral Au+Au collisions a correlation structure ascribed to minijet fragmentation is observed. It evolves with collision centrality and pt in a way not seen before, which suggests strong dissipation of minijet fragmentation in the longitudinally expanding medium.
We report high statistics measurements of inclusive charged hadron production in Au+Au and p+p collisions at sqrt[sNN]=200 GeV. A large, approximately constant hadron suppression is observed in central Au+Au collisions for 5<pT<12 GeV/c. The collision energy dependence of the yields and the centrality and pT dependence of the suppression provide stringent constraints on theoretical models of suppression. Models incorporating initial-state gluon saturation or partonic energy loss in dense matter are largely consistent with observations. We observe no evidence of pT-dependent suppression, which may be expected from models incorporating jet attenuation in cold nuclear matter or scattering of fragmentation hadrons.
Golgi phosphoprotein 3 (GOLPH3) is a conserved protein of the Golgi apparatus that in humans has been implicated in tumorigenesis. However, the precise function of GOLPH3 in malignant transformation is still unknown. Nevertheless, clinicopathological data shows that in more than a dozen kinds of cancer, including gliomas, GOLPH3 could be found overexpressed, which correlates with poor prognosis. Experimental data shows that overexpression of GOLPH3 leads to transformation of primary cells and to tumor growth enhancement. Conversely, the knocking down of GOLPH3 in GOLPH3-overexpressing tumor cells reduces tumorigenic features, such as cell proliferation and cell migration and invasion. The cumulative evidence indicate that GOLPH3 is an oncoprotein that promotes tumorigenicity by a mechanism that impact at different levels in different types of cells, including the sorting of Golgi glycosyltransferases, signaling pathways, and the actin cytoskeleton. How GOLPH3 connects mechanistically these processes has not been determined yet. Further studies are important to have a more complete understanding of the role of GOLPH3 as oncoprotein. Given the genetic diversity in cancer, a still outstanding aspect is how in this inherent heterogeneity GOLPH3 could possibly exert its oncogenic function. We have aimed to evaluate the contribution of GOLPH3 overexpression in the malignant phenotype of different types of tumor cells. Here, we analyzed the effect on cell migration that resulted from stable, RNAi-mediated knocking down of GOLPH3 in T98G cells of glioblastoma multiforme, a human glioma cell line with unique features. We found that the reduction of GOLPH3 levels produced dramatic changes in cell morphology, involving rearrangements of the actin cytoskeleton and reduction in the number and dynamics of focal adhesions. These effects correlated with decreased cell migration and invasion due to affected persistence and directionality of cell motility. Moreover, the knocking down of GOLPH3 also caused a reduction in autoactivation of focal adhesion kinase (FAK), a cytoplasmic tyrosine kinase that regulates focal adhesions. Our data support a model in which GOLPH3 in T98G cells promotes cell migration by stimulating the activity of FAK.
Lasioglossum is a large genus of halictid bees with high species diversity in morphologically rather cryptic species groups. With more than 1900 described species, the taxonomy of the genus is complex and largely unresolved in many regions. For practical reasons, systematic reviews are restricted in scope either geographically or to particular species groups. In this study we focus on the subgenus Dialictus of the genus Lasioglossum from the Yucatán Peninsula in Mexico. In previous studies we identified members of the genus as important pollinators of cash crops in the region, and genetic analyses suggested the existence of seven molecular taxonomic units (mOTU). Based on additional morphological differences, we here describe these mOTUs as novel species, Lasioglossum (Dialictus) yucatanense Landaverde-González sp. nov., L. (D.) paxtoni Landaverde-González sp. nov., L. (D.) ameshoferi Landaverde-González sp. nov., L. (D.) aureoviride Landaverde-González & Husemann sp. nov., L. (D.) paralepidii Gardner sp. nov., L. (D.) milpa Landaverde-González sp. nov. and L. (D.) nanotegula Landaverde-González & Husemann sp. nov., and provide keys and images to assist in their identification.
We report results on rho (770)0--> pi + pi - production at midrapidity in p+p and peripheral Au+Au collisions at sqrt[sNN]=200 GeV. This is the first direct measurement of rho (770)0--> pi + pi - in heavy-ion collisions. The measured rho 0 peak in the invariant mass distribution is shifted by ~40 MeV/c2 in minimum bias p+p interactions and ~70 MeV/c2 in peripheral Au+Au collisions. The rho 0 mass shift is dependent on transverse momentum and multiplicity. The modification of the rho 0 meson mass, width, and shape due to phase space and dynamical effects are discussed.
We treat 50 species of Pseudococcus Westwood (Hemiptera: Pseudococcidae) found in Central and South America. Sixteen new species are described and illustrated: Pseudococcus acaena Granara de Willink n. sp., P. bahiensis Granara de Willink n. sp., P. calchaquii Granara de Willink n. sp., P. chaquensis Granara de Willink n. sp., P. colombiensis Granara de Willink n. sp., P. cubaensis Granara de Willink n. sp., P. cuyoensis Granara de Willink n. sp., P. debilis Granara de Willink n. sp., P. dumetum Granara de Willink n. sp., P. insuetus Granara de Willink n. sp., P. lanatii Granara de Willink, n. sp., P. neuquenensis Granara de Willink n. sp., P. occultus Granara de Willink n. sp., P. panamaensis Granara de Willink n. sp., P. salazari Granara de Willink n. sp. and P. scatoterrae Granara de Willink n. sp. The new species are distributed in Argentina (9 spp.), Colombia (3 spp.), Brazil (2), Uruguay (2), Cuba (1), Panama (1) and Peru (1). Diagnostic characters and illustrations of 34 additional species are provided: Pseudococcus agavis McGregor, P. apomicrocirculus Gimpel and Miller, P. calceolariae (Maskell), P. comstocki (Kuwana), P. cribata González, P. cryptus Hempel, P. donrileyi Gimpel and Miller, P. elisae Borchsenius, P. eriocereus Williams, P. espeletiae Williams and Granara de Willink, P. galapagoensis Morrison, P. importatus McKenzie, P. insularis Morrison, P. jackbeardsleyi Gimpel and Miller, P. landoi (Balachowsky), P. longispinus (Targioni Tozzetti), P. mandio Williams, P. maritimus (Ehrhorn), P. meridionalis Prado, P. microcirculus McKenzie, P. nakaharai Gimpel and Miller, P. neomicrocirculus Gimpel and Miller, P. odermatti Miller and Williams, P. pabulum Granara de Willink, P. peregrinabundus Borchsenius, P. puertoricensis Gimpel and Miller, P. rosangelae Pacheco da Silva and Kaydan, P. saccharicola Takahashi, P. schusteri Gimpel and Miller, P. spanocera Gimpel and Miller, P. sociabilis Hambleton, P. solenedyos Gimpel and Miller, P. sorghiellus (Forbes) and P. viburni (Signoret). Five species from Argentina, two species from Jamaica and one species from Suriname are cited for the first time. Sixty-three figures, corresponding to the known species, their variations and new species cited for the region are included. A list of host plants containing 77 plant families and 355 species is included. An updated list of host plants and the distribution of some species of the genus is provided.
The Asterolecaniidae (Hemiptera: Coccomorpha), known as pit scales, are currently represented by 11 genera and 52 species in the Neotropical region, and by five species in Argentina. The goal of this study is to review and update the information currently known about the biodiversity of Asterolecaniidae in Argentina. We describe Argenta Granara de Willink new genus, Argenta eduardoi Granara de Willink new species, Mycetococcus ligae Granara de Willink new species, and Sclerosococcus williamsi Granara de Willink new species; an illustration of Pollinia pollini (Costa) is also included; the species Asterolecanium puteanum Russell and Russellaspis pustulans (Cockerell) are noted for the first time in Argentina. Dichotomous keys to the genera of Asterolecaniidae and the species of Asterolecanium Targioni-Tozzetti, Mycetococcus Ferris, and Sclerosococcus McKenzie in Argentina are presented. This work increases the number of known species in Argentina to ten.
ZooBank registration. urn:lsid:zoobank.org:pub:2A1FB016-1B67-4861-BB8B-2011B26679F1
We report on the rapidity and centrality dependence of proton and antiproton transverse mass distributions from 197Au + 197Au collisions at sqrt[sNN ]=130 GeV as measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Our results are from the rapidity and transverse momentum range of |y| <0.5 and 0.35< pt <1.00 GeV/c . For both protons and antiprotons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within |y| <0.5 . Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton (antiproton) yields and transverse mass distributions the possibility of prehadronic collective expansion may have to be taken into account.
The pseudorapidity asymmetry and centrality dependence of charged hadron spectra in d+Au collisions at sqrt[sNN ]=200 GeV are presented. The charged particle density at midrapidity, its pseudorapidity asymmetry, and centrality dependence are reasonably reproduced by a multiphase transport model, by HIJING, and by the latest calculations in a saturation model. Ratios of transverse momentum spectra between backward and forward pseudorapidity are above unity for pT below 5 GeV/c . The ratio of central to peripheral spectra in d+Au collisions shows enhancement at 2< pT <6 GeV/c , with a larger effect at backward rapidity than forward rapidity. Our measurements are in qualitative agreement with gluon saturation and in contrast to calculations based on incoherent multiple partonic scatterings.
We present data on e+ e- pair production accompanied by nuclear breakup in ultraperipheral gold-gold collisions at a center of mass energy of 200 GeV per nucleon pair. The nuclear breakup requirement selects events at small impact parameters, where higher-order diagrams for pair production should be enhanced. We compare the data with two calculations: one based on the equivalent photon approximation, and the other using lowest-order quantum electrodynamics (QED). The data distributions agree with both calculations, except that the pair transverse momentum spectrum disagrees with the equivalent photon approach. We set limits on higher-order contributions to the cross section.
Pion-kaon correlation functions are constructed from central Au+Au STAR data taken at sqrt[sNN]=130 GeV by the STAR detector at the Relativistic Heavy Ion Collider (RHIC). The results suggest that pions and kaons are not emitted at the same average space-time point. Space-momentum correlations, i.e., transverse flow, lead to a space-time emission asymmetry of pions and kaons that is consistent with the data. This result provides new independent evidence that the system created at RHIC undergoes a collective transverse expansion.
We report inclusive photon measurements about midrapidity ( |y| <0.5 ) from 197 Au + 197 Au collisions at sqrt[sNN ]=130 GeV at RHIC. Photon pair conversions were reconstructed from electron and positron tracks measured with the Time Projection Chamber (TPC) of the STAR experiment. With this method, an energy resolution of Delta E/E ~ 2% at 0.5 GeV has been achieved. Reconstructed photons have also been used to measure the transverse momentum ( pt ) spectra of pi 0 mesons about midrapidity ( |y| <1 ) via the pi 0 --> gamma gamma decay channel. The fractional contribution of the pi 0 --> gamma gamma decay to the inclusive photon spectrum decreases by 20%±5% between pt =1.65 GeV/c and pt =2.4 GeV/c in the most central events, indicating that relative to pi 0 --> gamma gamma decay the contribution of other photon sources is substantially increasing.
We present STAR measurements of the azimuthal anisotropy parameter v2 and the binary-collision scaled centrality ratio RCP for kaons and lambdas ( Lambda + Lambda -bar) at midrapidity in Au+Au collisions at sqrt[sNN]=200 GeV. In combination, the v2 and RCP particle-type dependencies contradict expectations from partonic energy loss followed by standard fragmentation in vacuum. We establish pT ~ 5 GeV/c as the value where the centrality dependent baryon enhancement ends. The K0S and Lambda + Lambda -bar v2 values are consistent with expectations of constituent-quark-number scaling from models of hadron formation by parton coalescence or recombination.
Midrapidity open charm spectra from direct reconstruction of D0(D0-bar)-->K± pi ± in d+Au collisions and indirect electron-positron measurements via charm semileptonic decays in p+p and d+Au collisions at sqrt[sNN]=200 GeV are reported. The D0(D0-bar) spectrum covers a transverse momentum (pT) range of 0.1<pT<3 GeV/c, whereas the electron spectra cover a range of 1<pT<4 GeV/c. The electron spectra show approximate binary collision scaling between p+p and d+Au collisions. From these two independent analyses, the differential cross section per nucleon-nucleon binary interaction at midrapidity for open charm production from d+Au collisions at BNL RHIC is d sigma NNcc-bar/dy=0.30±0.04(stat)±0.09(syst) mb. The results are compared to theoretical calculations. Implications for charmonium results in A+A collisions are discussed.
We present the results of charged particle fluctuations measurements in Au+Au collisions at sqrt[sNN ]=130 GeV using the STAR detector. Dynamical fluctuations measurements are presented for inclusive charged particle multiplicities as well as for identified charged pions, kaons, and protons. The net charge dynamical fluctuations are found to be large and negative providing clear evidence that positive and negative charged particle production is correlated within the pseudorapidity range investigated. Correlations are smaller than expected based on model-dependent predictions for a resonance gas or a quark-gluon gas which undergoes fast hadronization and freeze-out. Qualitative agreement is found with comparable scaled p+p measurements and a heavy ion jet interaction generation model calculation based on independent particle collisions, although a small deviation from the 1/N scaling dependence expected from this model is observed.
The transverse mass spectra and midrapidity yields for Xi s and Omega s are presented. For the 10% most central collisions, the Xi -bar+/h- ratio increases from the Super Proton Synchrotron to the Relativistic Heavy Ion Collider energies while the Xi -/h- stays approximately constant. A hydrodynamically inspired model fit to the Xi spectra, which assumes a thermalized source, seems to indicate that these multistrange particles experience a significant transverse flow effect, but are emitted when the system is hotter and the flow is smaller than values obtained from a combined fit to pi , K, p, and Lambda s.
Transverse energy ( ET ) distributions have been measured for Au+Au collisions at sqrt[sNN ]=200 GeV by the STAR Collaboration at RHIC. ET is constructed from its hadronic and electromagnetic components, which have been measured separately. ET production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of ET per charged particle agrees well with measurements at lower collision energy, indicating that the growth in ET for larger collision energy results from the growth in particle production. The electromagnetic fraction of the total ET is consistent with a final state dominated by mesons and independent of centrality.
The short-lived K(892)* resonance provides an efficient tool to probe properties of the hot and dense medium produced in relativistic heavy-ion collisions. We report measurements of K* in sqrt[sNN]=200GeV Au+Au and p+p collisions reconstructed via its hadronic decay channels K(892)*0-->K pi and K(892)*±-->K0S pi ± using the STAR detector at the Relativistic Heavy Ion Collider at Brookhaven National Laboratory. The K*0 mass has been studied as a function of pT in minimum bias p+p and central Au+Au collisions. The K*pT spectra for minimum bias p+p interactions and for Au+Au collisions in different centralities are presented. The K*/K yield ratios for all centralities in Au+Au collisions are found to be significantly lower than the ratio in minimum bias p+p collisions, indicating the importance of hadronic interactions between chemical and kinetic freeze-outs. A significant nonzero K*0 elliptic flow (v2) is observed in Au+Au collisions and is compared to the K0S and Lambda v2. The nuclear modification factor of K* at intermediate pT is similar to that of K0S but different from Lambda . This establishes a baryon-meson effect over a mass effect in the particle production at intermediate pT (2<pT <= 4GeV/c).