Inclusive pi(0), eta, and direct photon production at high transverse momentum in p plus p and d plus Au collisions at root s(NN)=200 GeV

We report a measurement of high-p(T) inclusive pi(0), eta, and direct photon production in p + p and d + Au collisions at root s(NN) = 200 GeV at midrapidity (0 < eta < 1). Photons from the decay pi(0) -> gamma gamma were detected in the barrel electromagnetic calorimeter of the STAR experiment at the Relativistic Heavy Ion Collider. The eta -> gamma gamma decay was also observed and constituted the first eta measurement by STAR. The first direct photon cross-section measurement by STAR is also presented; the signal was extracted statistically by subtracting the pi(0), eta, and omega(782) decay background from the inclusive photon distribution observed in the calorimeter. The analysis is described in detail, and the results are found to be in good agreement with earlier measurements and with next-to-leading-order perturbative QCD calculations.

Spectra of identified high-p(T) pi(+/-) and p((p)over-bar ) in Cu + Cu collisions at root s(NN)=200 GeV

We report new results on identified (anti) proton and charged pion spectra at large transverse momenta (3 < p(T) < 10 GeV/c) from Cu + Cu collisions at root s(NN) = 200 GeV using the STAR detector at the Relativistic Heavy Ion Collider (RHIC). This study explores the system size dependence of two novel features observed at RHIC with heavy ions: the hadron suppression at high-p(T) and the anomalous baryon to meson enhancement at intermediate transverse momenta. Both phenomena could be attributed to the creation of a new form of QCD matter. The results presented here bridge the system size gap between the available pp and Au + Au data, and allow for a detailed exploration of the onset of the novel features. Comparative analysis of all available 200 GeV data indicates that the system size is a major factor determining both the magnitude of the hadron spectra suppression at large transverse momenta and the relative baryon to meson enhancement.

Charged and strange hadron elliptic flow in Cu plus Cu collisions at root s(NN)=62.4 and 200 GeV

We present the results of an elliptic flow, v(2), analysis of Cu + Cu collisions recorded with the solenoidal tracker detector (STAR) at the BNL Relativistic Heavy Ion Collider at root s(NN) = 62.4 and 200 GeV. Elliptic flow as a function of transverse momentum, v(2)(p(T)), is reported for different collision centralities for charged hadrons h(+/-) and strangeness-ontaining hadrons K-S(0), Lambda, Xi, and phi in the midrapidity region vertical bar eta vertical bar < 1.0. Significant reduction in systematic uncertainty of the measurement due to nonflow effects has been achieved by correlating particles at midrapidity, vertical bar eta vertical bar < 1.0, with those at forward rapidity, 2.5 < vertical bar eta vertical bar < 4.0. We also present azimuthal correlations in p + p collisions at root s = 200 GeV to help in estimating nonflow effects. To study the system-size dependence of elliptic flow, we present a detailed comparison with previously published results from Au + Au collisions at root s(NN) = 200 GeV. We observe that v(2)(p(T)) of strange hadrons has similar scaling properties as were first observed in Au + Au collisions, that is, (i) at low transverse momenta, p(T) < 2 GeV/c, v(2) scales with transverse kinetic energy, m(T) - m, and (ii) at intermediate p(T), 2 < p(T) < 4 GeV/c, it scales with the number of constituent quarks, n(q.) We have found that ideal hydrodynamic calculations fail to reproduce the centrality dependence of v(2)(p(T)) for K-S(0) and Lambda. Eccentricity scaled v(2) values, v(2)/epsilon, are larger in more central collisions, suggesting stronger collective flow develops in more central collisions. The comparison with Au + Au collisions, which go further in density, shows that v(2)/epsilon depends on the system size, that is, the number of participants N-part. This indicates that the ideal hydrodynamic limit is not reached in Cu + Cu collisions, presumably because the assumption of thermalization is not attained.

Observation of pi(+)pi(-)pi(+)pi(-) photoproduction in ultraperipheral heavy-ion collisions at root s(NN)=200 GeV at the STAR detector

We present a measurement of pi(+)pi(-)pi(+)pi(-) photonuclear production in ultraperipheral Au-Au collisions at root s(NN) = 200 GeV from the STAR experiment. The pi(+)pi(-)pi(+)pi(-) final states are observed at low transverse momentum and are accompanied by mutual nuclear excitation of the beam particles. The strong enhancement of the production cross section at low transverse momentum is consistent with coherent photoproduction. The pi(+)pi(-)pi(+)pi(-) invariant mass spectrum of the coherent events exhibits a broad peak around 1540 +/- 40 MeV/c(2) with a width of 570 +/- 60 MeV/c(2), in agreement with the photoproduction data for the rho(0)(1700). We do not observe a corresponding peak in the pi(+)pi(-) final state and measure an upper limit for the ratio of the branching fractions of the rho(0)(1700) to pi(+)pi(-) and pi(+)pi(-)pi(+)pi(-) of 2.5% at 90% confidence level. The ratio of rho(0)(1700) and rho(0)(770) coherent production cross sections is measured to be 13.4 +/- 0.8(stat.) +/- 4.4(syst.)%.

Identified particle production, azimuthal anisotropy, and interferometry measurements in Au plus Au collisions at root s(NN)=9.2 GeV

We present the first measurements of identified hadron production, azimuthal anisotropy, and pion interferometry from Au + Au collisions below the nominal injection energy at the BNL Relativistic Heavy-Ion Collider (RHIC) facility. The data were collected using the large acceptance solenoidal tracker at RHIC (STAR) detector at root s(NN) = 9.2 GeV from a test run of the collider in the year 2008. Midrapidity results on multiplicity density dN/dy in rapidity y, average transverse momentum < p(T)>, particle ratios, elliptic flow, and Hanbury-Brown-Twiss (HBT) radii are consistent with the corresponding results at similar root s(NN) from fixed-target experiments. Directed flow measurements are presented for both midrapidity and forward-rapidity regions. Furthermore the collision centrality dependence of identified particle dN/dy, < p(T)>, and particle ratios are discussed. These results also demonstrate that the capabilities of the STAR detector, although optimized for root s(NN) = 200 GeV, are suitable for the proposed QCD critical-point search and exploration of the QCD phase diagram at RHIC.

Longitudinal scaling property of the charge balance function in Au plus Au collisions at root s(NN)=200 GeV

We present measurements of the charge balance function, from the charged particles, for diverse pseudorapidity and transverse momentum ranges in Au + Au collisions at root S-NN = 200 GeV using the STAR detector at RHIC. We observe that the balance function is boost-invariant within the pseudorapidity coverage vertical bar-1.3, 1.3 vertical bar. The balance function properly scaled by the width of the observed pseudorapidity window does not depend on the position or size of the pseudorapidity window. This scaling property also holds for particles in different transverse momentum ranges. In addition, we find that the width of the balance function decreases monotonically with increasing transverse momentum for all centrality classes. (c) 2010 Elsevier B.V. All rights reserved.

Postnatal development of the retina in root vole Microtus oeconomus

Vision plays an important role in the living habits of animals, especially in feeding. We investigated the postnatal development of retina in root vole Microtus oeconornus. The result shows that the retina of the M. oeconornus is very primitive before postnatal day （PD） 3. The neuroblastic layer does not differentiate and makes up more than half of the retina layer. The outer plexiform layer （OPL） first comes into existence at PDS. At PD6, as the presence of the OPL becomes obvious, the outer nuclear layer （ONL） and inner nuclear layer （INL） are much clearer. At PD18, the retina is similar to an adult retina and each layer becomes distinct. The thickness and cell density of the ganglion cell layer （GCL） and ONL during different postnatal days were also examined. These results show that the thickness and density of ONL increase during ontogeny, while the thickness and density of GCL decrease. Compared with Rattus norvegicus, Apodemus agrarius , Cricetulus triton, Microtus mandarinus , Myospalax cansus , Spermophilus dauricus and Sciurotamias davidianus, the histological structure of the retina of M. oeconornus is between that of nocturnal and diurnal rodents.

Effect of Tannic Acid on the Growth and Survival of Root Vles (Micortus oeconomus)

The objective of this study was to investigate the effects of tannic acid on the gworth and survival of small mammalian berbirvores. Measurements were conducted with weaned root voles fed with 3% or 6% tannic acid and 10% or 20% protein in their diets. The results indicated that the effect of tannic acid on growth rate of weaned root voles was greater when given a lower protein diet than a higher protein diet. After 20 d, with 10% protein diets, mean growth rates of the weaned voles fed with 3% or 6% tannic acid were -0.135 g/d and -0.25 g/d, respectively. When given 20% protein diet, mean growth rates of weaned root voles fed with 3% and 6% tannic acid for 20 d were 0.134 g/d and -0.116 g/d, respectively. Food utilization efficiencies of the voles fed with 3% and 6% tannic acid diets were significantly lower than that of the control diet at the level of 10% protein. When given the 20% protein diet, food utilization efficiencies of weaned voles fed with 6% tannic acid were significantly lower than that of the voles fed with 3% tannic acid diet or the control diet with the 10% protein diets, the average survival days of the weaned voles fed with 3% and 6% tannic acid diets decreased 26.23% and 49.36% compared to controls at the end of trial period, respectively. With 20% protein diets, the average survival of weaned voles given 6% tannic acid diet decreased 39.41% compared to controls at the end of trial period, although weaned voles given 3% tannic acid had a slight decrease of average survival days. The results of study suggested that tannins could substanitially affect the individual performance of weaned root voles.

Behavioural reaction of root vole (Microtus oeconomus pallas) males of different social ranks to familiar and novel odour of conspecific males

In this experiment, we tested the hypothesis that males of root voles (Microtus oeconomus Pallas) of different social ranks display different behavioural strategies. To document behavioural differences between social ranks, we investigated patterns in the behavioural responses to urine cues from familiar and novel individu in a choice maze. Ten pairs of male voles were efectively used in this experiment. All behaviour was recorded with OBSERVER 5.0. When experiment was finished, video tapes were transformed into digital data. Then all data were analyzed by SPSS. The results showed that the approach latency of subordinates was shorter for familiar odours than novel ones, dominant individuals preferentially entered the strange odourant box, subordinates preferred familiar odours over novel ones, subordinates spent more time visiting familiar odours compared to the novel odours, dominants preferred novel odours to familiar ones, subordinates approached familiar odours more frequently than novel ones and self-groomed more often in the familiar odourant box than in the novel box, and dominant and subordinate individuals showed significantly different countermarking behaviours to familiar and novel odours. In conclusion, the dominants and subordinates displayed different behaviour patterns when faced to familiar and novel conspecific males' urine cues. The data support our hypothesis that differences in social rank induce differences in behavioural patterns.