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Using the large acceptance Time Projection Chamber of experiment E895 at Brookhaven, measurements of collective sideward flow in Au+Au collisions at beam energies of 2A, 4A, 6A, and 8A GeV are presented in the form of in-plane transverse momentum and the first Fourier coefficient of azimuthal anisotropy v(1). These measurements indicate a smooth variation of sideward flow as a function of beam energy. The data are compared with four nuclear transport models which have an orientation towards this energy range. All four exhibit some qualitative trends similar to those found in the data, although none show a consistent pattern of agreement within experimental uncertainties.

Experimental heavy ion programs from the Bevalac, SIS, the AGS and the CERN SPS have attempted to characterize the distributions of particles emerging from high energy collisions in terms of simple thermodynamic principles. Testing the underlying assumptions of chemical and thermal equilibrations at different stages of the collision has been attempted by comparing model expectations to many different experimental observables. Static isotropic thermal emission models applied to observed particle rapidity distributions from experiments at all beam energies consistently fail to describe the observed shape; such model predictions being too narrow. Thermal models which include collective longitudinal expansion have been much more successful at reproducing the observed rapidity distributions [1,2]. The additional collective motion is attributed to intense pressure gradients which develop in the very hot, compressed nuclear matter fireballs created in heavy ion collisions.At the AGS, rapidity distributions of multiple particle species, including pions, kaons, protons and lambda hyperons from central collisions have been simultaneously described by a thermal distribution with a common longitudinal expansion velocity [2,3]. The agreement between the proton and other particle distributions suggests a high degree of stopping of the incident nucleons at the top AGS energy, which implies even more stopping at lower beam energies. However, recent investigations of the centrality dependence of the proton rapidity distributions from 6-11 AGeV Au+Au collisions by E917 suggest that the degree of nucleon stopping may be less than previously considered [4]. Nevertheless, their flat dN/dy for central collisions at all beam energies, fitted by sources distributed uniformly in rapidity to y-y cm = 0, could also be interpreted in the manner presented herein.For the asymptotic case at extremely high beam energies, Bjorken proposed [5] that nuclear transparency would evacuate the central rapidity region of all of the initial nucleons, leaving a hot, high-energy density region in which a Quark Gluon Plasma might form. In 160 AGeV Pb+Pb collisions at the CERN SPS, observed net proton ((+)-(-)) rapidity distributions [6] exhibit a double-humped character which is consistent with this transparency. At SPS energies, the nucleon distributions are not describable by a simple thermal model with only collective longitudinal flow, but rather need additional theoretical consideration of transparency. However, the negative hadron (mostly pions) rapidity distributions are well-described by this model, which might be interpreted as suggesting a significant amount of collective longitudinal flow for produced particles [2].

Introduction. Young women (20-35 years) are at high risk of HPV infection, although the majority of the infections are asymptomatic and are cleared spontaneously by the host immune system. These are also the group of women who are sexually active and are in the population of pregnant women. During pregnancy, the changes in the hormonal milieu and immune response may favor persistence of HPV infection and may aid in transgenerational transmission thereby furthering the cancer risk. In the present study, we determined the prevalence of vaginal HPV infection in early pregnancy and attempted to relate with pregnancy outcome. Material and Methods. Vaginal cytology samples were collected from the condoms used to cover the vaginal sonography probe during a routine first trimester visit to the hospital. All women were followed up throughout pregnancy and childbirth. Maternal and neonatal outcomes were recorded. Results. We found a prevalence of HPV infection around 39.4% in our population. Interestingly all HPV positive women were infected with one or more high risk HPV viruses with an overlap of intermediate and low risk in 43% and 7.3%, respectively. Women with preterm prelabor rupture of membranes (PPROM) showed a statistically higher incidence in HPV positive (7.3%) group as compared to the HPV negative (3.2%) group. Conclusion. The prevalence of genital HPV infection is high during pregnancy (around 40%) and was associated with higher incidence of PPROM.