Studying Intermediate pT Hadron Production with Fluctuations

Mechanisms for particle production at intermediate pT in nuclear collisions at RHIC are discussed, emphasizing the differences in associated jet-like correlations between color-neutral and colored production. An alternative production mechanism involving both recombination and fragmentation is suggested, which might simultaneously lead to an enhancement of baryons and to jet-like correlations. To gain more insight into the relative importance of different mechanisms a study of constrained distributions of associated multiplicity is proposed. In a simple model it is shown that these multiplicity distributions may change significantly, if the nature of the production mechanism fluctuates from event to event.Comment: 7 pages, 4 figures, talk at Hot Quarks 2004 conferenc

Baryon deceleration by strong chromofields in ultrarelativistic nuclear collisions

It is assumed that strong chromofields are generated at early stages of ultrarelativistic heavy-ion collisions which give rise to a collective deceleration of net baryons from colliding nuclei. We have solved classical equations of motion for baryonic slabs under the action of a time-dependent longitudinal chromoelectric field. It is demonstrated that the slab final rapidities are rather sensitive to the strength and decay time of the chromofield as well as to the back reaction of the produced partonic plasma. The net-baryon rapidity loss of about 2 units, found for most central Au-Au collisions at RHIC, can be explained by the action of chromofields with the initial energy density of about 50 GeV/fm^3. Predictions for the baryon stopping at the LHC are made.Comment: 10 pages in revtex, 3 eps figure

Markierungsversuche und Modellierung zur Bewertung der Gefährdung eines Trinkwasserbrunnens

Kurzfassung: In einem Porengrundwasserleiter aus Niederterrassenschottern bei Pratteln, Schweiz, wurde ein Markierungsversuch mit Uranin durchgeführt, um die Gefährdung eines Trinkwasserbrunnens durch ein 760 m talaufwärts gelegenen Ablagerungsstandort zu bewerten. Dabei wurde eine maximale Abstandsgeschwindigkeit von 127 m/d und ein Wiedererhalt von 0,93 % festgestellt. Der Tracer wurde auch in zwei intermediären Beobachtungsbrunnen nachgewiesen. Diese Studie diskutiert die Ursachen dieser hohen Fließgeschwindigkeit. Durch drei verschiedene analytische Modelle konnten die Durchgangskurven simuliert und Transportparameter bestimmt werden. Erst die Anwendung eines zweidimensionalen numerischen Modells (FEFLOW) mit vereinfachter Geometrie liefert aber eine hydrogeologisch konsistente, mögliche Erklärung aller Versuchsergebnisse. Demnach handelt es sich vermutlich um einen relativ homogenen Grundwasserleiter. Der steile Gradient (6 ‰) und die hohe Durchlässigkeit (3 · 10-2 m/s) verursachen die hohen Fließgeschwindigkeiten. Der Hauptteil der Tracerwolke strömt seitlich an den Brunnen vorbei. Durch später durchgeführte Kleinpumpversuche wurde diese Modellvorstellung weitgehend bestätigt. Diese Befunde sollten bei Schutz- und Sanierungskonzepten berücksichtigt werde

Long-Term Effectiveness of Radar Speed Display Signs in a University Environment

Vehicular speeds are of particular interest in areas with a high number of pedestrians due to the fact that 14-percent of all fatal crashes involve pedestrians. This study investigated the effect of a radar speed display sign placed for an extended period of time, at a location frequented by law enforcement on a road segment entering a university campus with a high number of pedestrians and vehicle speed violations. The statistical analysis included a comparison between AM peak, PM peak, and midday speeds collected one year apart. The data suggested that radar speed display signs can remain effective over a long period of time; causing drivers to decelerate when warned of a speeding violation. While other studies have examined long-term impacts of similar technologies, none have included a road entering a University campus. Thus, these findings support that other similar locations entering university campuses could see long-term benefits to stationary radar speed display signs

Resonance decay effects on anisotropy parameters

We present the elliptic flow $v_2$ of pions produced from resonance decays. The transverse momentum $p_T$ spectra of the parent particles are taken from thermal model fits and their $v_2$ are fit under the assumption that they follow number-of-constituent-quark (NCQ) scaling expected from quark-coalescence models. The $v_2$ of pions from resonance particle decays is found to be similar to the measured pion $v_2$. We also propose the measurement of electron $v_2$ as a means to extract open-charm $v_2$ and investigate whether a thermalized system of quarks and gluons (a quark-gluon plasma) is created in collisions of Au nuclei at RHIC.Comment: 5 pages, 4 figure

Streptococcus suis in German pig holdings—conventional and molecular detection

Streptococcus suis (S. suis) is a zoonotic agent worldwide. Pigs are the main reservoir, mostly asymptomatic. Humans get the infection by contact and consumption of contaminated meat and meat products. In this study, samples from 38 pig carcasses fit for human consumption from 17 holdings were arbitrarily selected. From each carcass, seven tissue samples were taken and examined for the presence of S. suis, using conventional microbiology and PCR. In addition, virulence-associated factors (epf, arcA, sly, mrp) were tested with PCR. More isolates were PCR-positive for S. suis as compared to conventional testing, mostly in samples from the heart and from the mandibular lymphnodes. All isolates were epf negative, combinations of arcA, sly and mrp were found in some isolates. Six isolates were positive for arcA and mrp, five for arcA and sly. For three isolates the triple combination arcA + mrp + sly was found. These isolates originated from different pigs

How Student Written Communication Skills Benefit During Participation in an Industry-Sponsored Civil Engineering Capstone Course

Because many engineering programs use capstone design courses and value strong communication abilities, authors sought to identify how student written communication skills changed because of industry-sponsored capstone design projects. A student exit survey was collected at the end of the capstone design course during faculty-led projects and projects led by practicing engineers in industry. These results led the researchers to subsequently evaluate two semesters of before-andafter writing samples using a rubric. Student surveys suggested a statistically significant increase in learning about professional issues, problem solving, and written/oral communication. Evaluation of student writing samples suggests that the students significantly improved their grammar/spelling and their organization of content during the course. These findings suggest that industry-sponsored projects help students recognize the relation between professionalism and correspondence that is organized and void of grammar and spelling errors

High Energy Nuclear Collisions: Theory Overview

We review some basic concepts of Relativistic Heavy Ion Physics and discuss our understanding of some key results from the experimental program at the Relativistic Heavy Ion Collider (RHIC). We focus in particular on the early time dynamics of nuclear collisions, some result from lattice QCD, hard probes and photons.Comment: 11 pages, 3 figures; delivered at ISNP 2009, published in Praman

Prospects for strangeness measurement in ALICE

The study of strangeness production at LHC will bring significant information on the bulk chemical properties, its dynamics and the hadronisation mechanisms involved at these energies. The ALICE experiment will measure strange particles from topology (secondary vertices) and from resonance decays over a wide range in transverse momentum and shed light on this new QCD regime. These motivations will be presented as well as the identification performance of ALICE for strange hadrons.Comment: 12 pages, 11 figures Proceedings of the Workshop on Relativistic Nuclear Physics (WRNP) 2007, Kiev, Ukraine Conference Info: http://wrnp2007.bitp.kiev.ua/ Submitted to "Physics of Atomic Nuclei

Identifying the Safety Impact of Signal Coordination Projects along Urban Arterials Using a Meta-analysis Method

The safety impact of changes to roadway operations have been of interests in recent years with the publication of the Highway Safety Manual. One area that is in need of further study is the safety impact of traffic signal coordination projects in urban areas. Specifically, this study seeks to identify the safety benefit from traffic signal coordination projects on major arterial roadways through urban areas using a before and after study with a comparison groups approach and a meta-analysis method. The findings suggest that traffic signal coordination could decrease total crashes by 21 percent, injury crashes by 52 percent and property-damage-only crashes by 21 percent. The results can be utilized by engineering practitioners to estimate the safety benefits for projects that seek to coordinate traffic signals along an urban corridor. Because these projects can both improve the safety of roadways while improving traffic flow, the application of these findings could be broad