The ALICE experiment is designed to study the properties of hadron and nucleus collisions in a new energy regime at the Large Hadron Collider at CERN. A fundamental observable in such collisions is ...the multiplicity distribution of charged particles. A forward multiplicity detector has been designed to extend the charged particle multiplicity coverage of the ALICE experiment to pseudorapidities of
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. This detector consists of five rings, each containing 10240 Si strips, divided into sectors comprised of Si sensors bonded and glued to hybrid PC boards equipped with radiation hard preamplifiers. The output of these preamplifiers is multiplexed into custom-made fast ADC chips located directly behind the Si sensors on the detector frame. These ADCs are read out, via optical fibers, to a data acquisition farm of commodity PCs. The design and characteristics of the ALICE Forward Multiplicity Detector will be discussed.
Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z = 7), are measured in ...PHOBOS. These fragments are observed in Au+Au ( sNN=19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (η). The dominant multiply-charged fragment is the tightly bound helium (α), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. In this paper, we observe that in Cu+Cu collisions, it becomes much more favorable for the α fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. Finally, a detailed comparison of the shapes for α and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.
The use of classic anti-psychotic drugs in the long-term treatment of schizophrenia is associated with risk for extrapyramidal side-effects, such as akathisia, parkinsonism and tardive dyskinesia ...(TD). Approximately 5-10% of European Caucasians lack the cytochrome P450 enzyme CYP2D6 (so-called poor metabolizers; PM), which normally metabolizes several drugs including many neuroleptics. PM subjects may achieve high or toxic plasma levels upon standard drug therapy. In this study we have examined 100 subjects from the Nithsdale cohort of schizophrenic patients in South-west Scotland receiving long-term neuroleptic medication, which enabled us to perform both a cross-sectional and longitudinal evaluation of extrapyramidal side-effects in relation to the genetically impaired CYP2D6 metabolism. We identified ten (10%) schizophrenic subjects with the PM genotype. In the cross-sectional study, the prevalence of TD, parkinsonism and akathisia was 51%, 38% and 15%, respectively. Patients with TD or parkinsonism were significantly older than patients without these side-effects. In contrast, patients with akathisia were significantly younger than patients without akathisia. There was a non-significant tendency for PM subjects to have more severe ratings for TD and parkinsonism. In the long-term evaluation based on repeated ratings since 1981, there was a non-significant 3-fold higher frequency of PM subjects among schizophrenic patients with longitudinal TD, as compared with the group of patients with fluctuating or no TD. These results indicate that genetically impaired CYP2D6 metabolism may be a contributing factor for the development of persistent TD.
Spectator fragments resulting from relativistic heavy ion collisions, consisting of single protons and neutrons along with groups of stable nuclear fragments up to nitrogen (Z = 7), are measured in ...PHOBOS. These fragments are observed in Au+Au (root s(NN) = 19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high pseudorapidity (eta). The dominant multiply-charged fragment is the tightly bound helium (alpha), with lithium, beryllium, and boron all clearly seen as a function of collision centrality and pseudorapidity. We observe that in Cu+Cu collisions, it becomes much more favorable for the alpha fragments to be released than lithium. The yields of fragments approximately scale with the number of spectator nucleons, independent of the colliding ion. The shapes of the pseudorapidity distributions of fragments indicate that the average deflection of the fragments away from the beam direction increases for more central collisions. A detailed comparison of the shapes for alpha and lithium fragments indicates that the centrality dependence of the deflections favors a scaling with the number of participants in the collision.
We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrts_{NN}=22.4, 62.4, and 200 ...GeV, over a wide range of pseudorapidity, using the PHOBOS detector. A comparison of Cu+Cu and Au+Au results shows that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same N{part}/2A rather than the same N_{part}. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.
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