| 1. |
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| 2. |
- Adcox, K, et al.
(författare)
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PHENIX detector overview
- 2003
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Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - 0167-5087. ; 499:2-3, s. 469-479
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Tidskriftsartikel (refereegranskat)abstract
- The PHENIX detector is designed to perform a broad study of A-A, p-A, and p-p collisions to investigate nuclear matter under extreme conditions. A wide variety of probes, sensitive to all timescales, are used to study systematic variations with species and energy as well as to measure the spin structure of the nucleon. Designing for the needs of the heavy-ion and polarized-proton programs has produced a detector with unparalleled capabilities. PHENIX measures electron and muon pairs, photons, and hadrons with excellent energy and momentum resolution. The detector consists of a large number of subsystems that are discussed in other papers in this volume. The overall design parameters of the detector are presented. (C) 2002 Elsevier Science B.V. All rights reserved.
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| 3. |
- Adler, SS, et al.
(författare)
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Double helicity asymmetry in inclusive midrapidity pi(0) production for polarized p+p collisions at root s=200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:20: 202002
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Tidskriftsartikel (refereegranskat)abstract
- We present a measurement of the double longitudinal spin asymmetry in inclusive pi(0) production in polarized proton-proton collisions at roots=200 GeV. The data were taken at the Relativistic Heavy Ion Collider with average beam polarizations of 0.27. The measurements are the first in a program to study the longitudinal spin structure of the proton, using strongly interacting probes, at collider energies. The asymmetry is presented for transverse momenta 1-5 GeV/c at midrapidity, where next-to-leading-order perturbative quantum chromodynamic (NLO pQCD) calculations well describe the unpolarized cross section. The observed asymmetry is small and is compared to a NLO pQCD calculation with a range of polarized gluon distributions.
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| 4. |
- Adler, SS, et al.
(författare)
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Bose-Einstein correlations of charged pion pairs in Au+Au collisions at root(NN)-N-s = 200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 93:15
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Tidskriftsartikel (refereegranskat)abstract
- Bose-Einstein correlations of identically charged pion pairs were measured by the PHENIX experiment at midrapidity in Au+Au collisions at roots(NN)=200 GeV. The Bertsch-Pratt radius parameters were determined as a function of the transverse momentum of the pair and as a function of the centrality of the collision. Using the standard core-halo partial Coulomb fits, and a new parametrization which constrains the Coulomb fraction as determined from the unlike-sign pion correlation, the ratio R-out/R-side is within 0.8-1.1 for 0.25<<1.2 GeV/c. The centrality dependence of all radii is well described by a linear scaling in N-part(1/3), and R-out/R-side for similar to0.45 GeV/c is approximately constant at unity as a function of centrality.
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| 5. |
- Adler, SS, et al.
(författare)
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J/psi production from proton-proton collisions at root s=200 GeV
- 2004
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Ingår i: Physical Review Letters. - 1079-7114. ; 92:5
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Tidskriftsartikel (refereegranskat)abstract
- J/psi production has been measured in proton-proton collisions at roots=200 GeV over a wide rapidity and transverse momentum range by the PHENIX experiment at the Relativistic Heavy Ion Collider. Distributions of the rapidity and transverse momentum, along with measurements of the mean transverse momentum and total production cross section are presented and compared to available theoretical calculations. The total J/psi cross section is 4.0+/-0.6(stat)+/-0.6(syst)+/-0.4(abs) mub. The mean transverse momentum is 1.80+/-0.23(stat)+/-0.16(syst) GeV/c.
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| 6. |
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| 7. |
- Adler, SS, et al.
(författare)
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Elliptic flow of identified hadrons in Au+Au collisions at root s(NN)=200 GeV
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:18: 182301
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Tidskriftsartikel (refereegranskat)abstract
- The anisotropy parameter (v(2)), the second harmonic of the azimuthal particle distribution, has been measured with the PHENIX detector in Au+Au collisions at roots(NN)=200 GeV for identified and inclusive charged particle production at central rapidities (eta<0.35) with respect to the reaction plane defined at high rapidities (eta=3-4 ). We observe that the v(2) of mesons falls below that of (anti)baryons for p(T)>2 GeV/c, in marked contrast to the predictions of a hydrodynamical model. A quark-coalescence model is also investigated.
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| 8. |
- Adler, SS, et al.
(författare)
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J/psi production in Au-Au collisions at root s(NN)=200 GeV
- 2004
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 69:1
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Tidskriftsartikel (refereegranskat)abstract
- First results on charm quarkonia production in heavy ion collisions at the Relativistic Heavy Ion Collider (RHIC) are presented. The yield of J/psi's measured in the PHENIX experiment via electron-positron decay pairs at midrapidity for Au-Au reactions at roots(NN) = 200 GeV is analyzed as a function of collision centrality. For this analysis we have studied 49.3x10(6) minimum bias Au-Au reactions. We present the J/psi invariant yield dN/dy for peripheral and midcentral reactions. For the most central collisions where we observe no signal above background, we quote 90% confidence level upper limits. We compare these results with our J/psi measurement from proton-proton reactions at the same energy. We find that our measurements are not consistent with models that predict strong enhancement relative to binary collision scaling.
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| 9. |
- Adler, SS, et al.
(författare)
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Scaling properties of proton and antiproton production in root s(NN)=200 GeV Au+Au collisions
- 2003
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Ingår i: Physical Review Letters. - 1079-7114. ; 91:17: 172301
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Tidskriftsartikel (refereegranskat)abstract
- We report on the yield of protons and antiprotons, as a function of centrality and transverse momentum, in Au+Au collisions at rootS(NN)=200 GeV measured at midrapidity by the PHENIX experiment at the BNL Relativistic Heavy Ion Collider. In central collisions at intermediate transverse momenta (1.5
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| 10. |
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| 11. |
- Wijesooriya, K, et al.
(författare)
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Polarization measurements in high-energy deuteron photodisintegration
- 2001
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Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 86:14, s. 2975-2979
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the recoil proton polarization for the d(γ⃗,p⃗)n reaction at θc.m. = 90° for photon energies up to 2.4 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. The induced polarization py vanishes above 1 GeV, contrary to meson-baryon model expectations, in which resonances lead to large polarizations. However, the polarization transfer Cx does not vanish above 1 GeV, inconsistent with hadron helicity conservation. Thus, we show that the scaling behavior observed in the d(γ,p)ncross sections is not a result of perturbative QCD. These data should provide important tests of new nonperturbative calculations in the intermediate energy regime.
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| 12. |
- Schlegel, C, et al.
(författare)
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K-isomers in very neutron-rich nuclei around mass 180
- 2000
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Ingår i: Physica Scripta. Topical Issues. - 0281-1847. ; T88, s. 72-76
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Tidskriftsartikel (refereegranskat)abstract
- gamma-spectroscopy methods have been used to search for microsecond isomers among the fragmentation products of a 1 GeV/nucleon Pb-208 beam. In particular the population of the known K-pi = 35/2(-) isomer in W-179 has been investigated and several new isomeric decays have been found for neutron rich nuclei in the A approximate to 180-200 mass region. The ground state band of the neutron rich N = 116 system of W-190 has been identified for the first time and we discuss its structure in comparison to neighboring systems.
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| 13. |
- Schulte, EC, et al.
(författare)
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High energy angular distribution measurements of the exclusive deuteron photodisintegration reaction
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - : American Physical Society. - 0556-2813 .- 1089-490X. ; 66:4
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Tidskriftsartikel (refereegranskat)abstract
- The first complete measurements of the angular distributions of the two-body deuteron photodisintegration differential cross section at photon energies above 1.6 GeV were performed at the Thomas Jefferson National Accelerator Facility. The results show a persistent forward-backward asymmetry up to E-gamma=2.4 GeV, the highest-energy measured in this experiment. The Hard Rescattering and the Quark-Gluon string models are in fair agreement with the results.
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| 14. |
- Wijesooriya, K, et al.
(författare)
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Polarization measurements in neutral pion photoproduction
- 2002
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 66:3
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Tidskriftsartikel (refereegranskat)abstract
- We present measurements of the recoil proton polarization for the H-1((γ) over right arrow,(p) over right arrow)pi(0) reaction for theta(c.m.)(pi) = 60degrees-135degrees and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region.
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| 15. |
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| 16. |
- Berlow, E.L., et al.
(författare)
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Interaction strengths in food webs : Issues and opportunities
- 2004
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 73:3, s. 585-598
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Forskningsöversikt (refereegranskat)abstract
- 1. Recent efforts to understand how the patterning of interaction strength affects both structure and dynamics in food webs have highlighted several obstacles to productive synthesis. Issues arise with respect to goals and driving questions, methods and approaches, and placing results in the context of broader ecological theory. 2. Much confusion stems from lack of clarity about whether the questions posed relate to community-level patterns or to species dynamics, and to what authors actually mean by the term 'interaction strength'. Here, we describe the various ways in which this term has been applied and discuss the implications of loose terminology and definition for the development of this field. 3. Of particular concern is the clear gap between theoretical and empirical investigations of interaction strengths and food web dynamics. The ecological community urgently needs to explore new ways to estimate biologically reasonable model coefficients from empirical data, such as foraging rates, body size, metabolic rate, biomass distribution and other species traits. 4. Combining numerical and analytical modelling approaches should allow exploration of the conditions under which different interaction strengths metrics are interchangeable with regard to relative magnitude, system responses, and species identity. 5. Finally, the prime focus on predator-prey links in much of the research to date on interaction strengths in food webs has meant that the potential significance of nontrophic interactions, such as competition, facilitation and biotic disturbance, has been largely ignored by the food web community. Such interactions may be important dynamically and should be routinely included in future food web research programmes.
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| 17. |
- Fox, A, et al.
(författare)
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Increased levels of bacterial markers and CO2 in occupied school rooms
- 2003
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry (RSC). - 1464-0325 .- 1464-0333. ; 5:2, s. 246-252
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Tidskriftsartikel (refereegranskat)abstract
- Our group previously demonstrated that carbon dioxide (CO2) levels in heavily occupied schools correlate with the levels of airborne bacterial markers. Since CO2 is derived from the room occupants, it was hypothesized that in schools, bacterial markers may be primarily increased in indoor air because of the presence of children: directly from skin microflora or indirectly, by stirring up dust from carpets and other sources. The purpose of this project was to test the hypothesis. Muramic acid (Mur) is found in almost all bacteria whereas 3-hydroxy fatty acids (3-OH FAs) are found only in Gram-negative bacteria. Thus Mur and 3-OH FA serve as markers to assess bacterial levels in indoor air (pmol m-3). In our previous school studies, airborne dust was collected only from occupied rooms. However, in the present study, additional dust samples were collected from the same rooms each weekend when unoccupied. Samples were also collected from outside air. The levels of dust, Mur and Cu-10:0, C-12:0, C-14:0, and C-16:0 3-OH FAs were each much higher (range 5 50 fod) in occupied rooms than in unoccupied school rooms. Levels in outdoor air were much lower than that of indoor air from occupied classrooms and higher than the levels in the same rooms when unoccupied. The mean CO2 concentrations were around 420 parts per million (ppm) in unoccupied rooms and outside air: and they ranged from 1017 to 1736 ppm in occupied rooms, regularly exceeding 800-1000 ppm, which are the maximum levels indicative of adequate indoor ventilation. This indicates that the children were responsible for the increased levels of bacterial markers. However, the concentration of Mur in dust was also 6 fold higher in occupied rooms (116.5 versus 18.2 pmole mg(-1)). This further suggests that airborne dust present in occupied and unoccupied rooms is quite distinct. In conclusion in unoccupied rooms, the dust was of environmental origin but the children were the primary source in occupied rooms.
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| 18. |
- Holgate, S. T., et al.
(författare)
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Efficacy and safety of a recombinant anti-immunoglobulin E antibody (omalizumab) in severe allergic asthma
- 2004
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Ingår i: Clin Exp Allergy. ; 34:4
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Patients with severe asthma are often inadequately controlled on existing anti-asthma therapy, constituting an unmet clinical need. OBJECTIVE: This randomized, double-blind, placebo-controlled trial evaluated the ability of omalizumab, a humanized monoclonal anti-IgE antibody, to improve disease control sufficiently to enable inhaled corticosteroid reduction in patients with severe allergic asthma. METHODS: After a run-in period when an optimized fluticasone dose (> or =1000 microg/day) was received for 4 weeks, patients were randomized to receive subcutaneous omalizumab [minimum 0.016 mg/kg/IgE (IU/mL) per 4 weeks; n=126] or matching placebo (n=120) at intervals of 2 or 4 weeks. The study comprised a 16-week add-on phase of treatment followed by a 16-week fluticasone-reduction phase. Short-/long-acting beta(2)-agonists were allowed as needed. RESULTS: Median reductions in fluticasone dose were significantly greater with omalizumab than placebo: 60% vs. 50% (P=0.003). Some 73.8% and 50.8% of patients, respectively, achieved a > or =50% dose reduction (P=0.001). Fluticasone dose reduction to < or =500 microg/day occurred in 60.3% of omalizumab recipients vs. 45.8% of placebo-treated patients (P=0.026). Through both phases, omalizumab reduced rescue medication requirements, improved asthma symptoms and asthma-related quality of life compared to placebo. CONCLUSION: Omalizumab treatment improves asthma control in severely allergic asthmatics, reducing inhaled corticosteroid requirements without worsening of symptom control or increase in rescue medication use.
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| 19. |
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