Physics Revealed at Intermediate p_T

A review is given on the subject of hadron production at intermediate $p_T$ in heavy-ion collisions. The underlying dynamical processes are inferred from interpreting the data in the framework of recombination. Ridge formation with or without triggers is found to play an important role in nearly all observables in that $p_T$ region. Correlation data would be hard to interpret without taking ridges into account. The semi-hard partons that create the ridges may even be able to drive elliptic flow without fast thermalization.Comment: 8 pages, plenary talk given at Quark Matter 2008, Jaipur, Indi

A Hydrodynamic and Transport Model for Ultrarelativistic Heavy Ion Collisions at RHIC and LHC Energies

Combining the hydrodynamic model (Hydro code) and the transport model (PACIAE model), we present the Hydro-PACIAE hybrid model. We use the Hydro-PACIAE hybrid model to calculate Au+Au collisions at $\sqrt{s_{NN}}$=130 GeV and Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV. The obtained pseudo-rapidity and transverse momentum distributions well reproduce the experimental data. This shows that the Hydro-PACIAE hybrid model is useful to describe the ultrarelativistic Heavy Ion Collisions at RHIC and LHC Energies. We used the hybrid model to calculate the elliptical flow for the Pb+Pb collisions at $\sqrt{s_{NN}}$=2.76 TeV. The $v_2$ values are bigger than the experimental data at high $p_T$, and will become bigger when the Hydro evolution time is longer. The results indicate that the selection of the transition hypersurface has significant effect on the observable quantities.Comment: 8 pages, 8 figure

Genetic markers of resistance to pyrimethamine and sulfonamides in Plasmodium falciparum parasites compared with the resistance patterns in isolates of Escherichia coli from the same children in Guinea-Bissau.

The antifolate drugs sulphadoxine and pyrimethamine are used for treatment of chloroquine-resistant Plasmodium falciparum in Africa. Resistance to pyrimethamine has been associated with point mutations in the dhfr-gene and resistance to sulphadoxine with mutations in the dhps-gene. There is concern that the use of the antifolates trimethoprim and sulphamethoxazole for treatment of other infectious diseases will result in the selection of malaria parasites with mutations in these genes. In Guinea-Bissau, where sulfonamide and trimethoprim-containing drugs have been used extensively, we decided to assess the prevalence of mutations in the dhfr-and dhps-gene in P. falciparum isolated from children suffering from acute malaria and to assess the resistance patterns to trimethoprim/sulphamethoxazole in Escherichia coli isolated from the same patients. A thick film and a blood sample for polymerase chain reaction (PCR) were obtained from 100 children attending the Bandim Health Centre in Bissau with symptoms compatible with malaria. Furthermore, a stool sample was collected from the same children and cultured for E. coli. Of the cultured E. coli, 67% were resistant both to sulfonamides and trimethoprim, 4% to sulfonamides alone, 3% to trimethoprim alone while 26% were fully sensitive to both drugs. PCR was successfully performed in 97 blood samples. Of these, 41% had triple mutations at the dhfr-gene (at codons 51, 59 and 108), and 15% had triple mutations plus mutation at codon 437 in the dhps-gene. Only 45% harboured the wild-type dhfr-gene. Thus both bacterial resistance and mutations in the parasitic genes were common, but not linked in the individual child. As sulphadoxine-pyrimethamine has only been used as a second line treatment for chloroquine resistant malaria in Guinea-Bissau for a few years, it is worrying to find a high prevalence of mutations in the parasitic genes coding for resistance to these drugs. Therefore, restricting the use of sulphadoxine-pyrimethamine for the treatment of chloroquine resistant malaria might not be sufficient to prevent the development of resistance in the parasites as long as antifolate drugs are used extensively

Antarctic intertidal macroalgae under predicted increased temperatures mediated by global climate change: Would they cope?

The Antarctic Peninsula is one of the regions to be most affected by increase in sea surface temperatures (SSTs) mediated by Global Climate Change; indeed, most negative predictions imply an up to 6 °C increment by the end of the XXI century. Temperature is one of the most important factors mediating diversity and distribution of macroalgae, although there is still no consensus as to the likely effects of higher SSTs, especially for polar seaweeds. Some available information suggests that potential strategies to withstand future increases in SSTs will be founded upon the glutathione-ascorbate cycle and the induction of chaperone-functioning heat shock proteins (HSPs); however, their eventual role, even for general stress responses, is unclear. The intertidal green, brown and red macroalgae species Monostroma hariotii, Adenocystis utricularis and Pyropia endiviifolia, respectively, from King George Island, Antarctic Peninsula, were exposed to 2 °C (control) and 8 °C (climate change scenario) for up to 5 days (d). Photosynthetic activity (αETR and ETRmax, and EkETR), photoinhibition (Fv/Fm) and photoprotection processes (αNPQ, NPQmax, and EkNPQ) provided no evidence of negative ecophysiological effects. There were moderate increases in H2O2 production and levels of lipid peroxidation with temperature, results supported by stable levels of total glutathione and ascorbate pools, with mostly higher levels of reduced ascorbate and glutathione than oxidized forms in all species. Transcripts of P. endiviifolia indicated a general upregulation of all antioxidant enzymes and HSPs genes studied under warmer temperature, although with different levels of activation with time. This pioneering investigation exploring different levels of biological organization, suggested that Antarctic intertidal macroalgae may be able to withstand future rise in SSTs, probably slightly altering their latitudinal distribution and/or range of thermal tolerance, by exhibiting robust glutathione-ascorbate production and recycling, as well as the induction of associated antioxidant enzymatic machinery and the syntheses of HSPs.This work was financed and logistic support granted through the projects INACH (Chilean Antarctic Institute) RT_09_16 and RG_10_18 directed by C.A. Sáez and P.S.M. Celis-Plá, respectively. P. Huovinen and I. Gómez were funded by Fondap IDEAL 15150003, while C. Lavergne was funded by ANID FONDECYT Postdoctorado (#3180374) and Fernanda Rodríguez-Rojas by ANID FONDECYT Postdoctorado (#3180394)