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We present the first measurement of the proton–Ω correlation function in heavy-ion collisions for the central (0–40%) and peripheral (40–80%) Au + Au collisions at √sNN = 200 GeV by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). Predictions for the ratio of peripheral collisions to central collisions for the proton–Ω correlation function are sensitive to the presence of a nucleon– bound state. These predictions are based on the proton– interaction extracted from (2 + 1)-flavor lattice QCD calculations at the physical point. The measured ratio of the proton–Ω correlation function between the peripheral (small system) and central (large system) collisions is less than unity for relative momentum smaller than 40 MeV/c. Comparison of our measured correlation ratio with theoretical calculation slightly favors a proton– bound system with a binding energy of ∼ 27 MeV.
Elliptic flow of heavy-flavor decay electrons in Au+Au collisions at √sNN = 27 and 54.4 GeV at RHIC
(2023)
We report on new measurements of elliptic flow (v2) of electrons from heavy-flavor hadron decays at mid-rapidity (|y|<0.8) in Au+Au collisions at sNN−−−√ = 27 and 54.4 GeV from the STAR experiment. Heavy-flavor decay electrons (eHF) in Au+Au collisions at sNN−−−√ = 54.4 GeV exhibit a non-zero v2 in the transverse momentum (pT) region of pT< 2 GeV/c with the magnitude comparable to that at sNN−−−√=200 GeV. The measured eHF v2 at 54.4 GeV is also consistent with the expectation of their parent charm hadron v2 following number-of-constituent-quark scaling as other light and strange flavor hadrons at this energy. These suggest that charm quarks gain significant collectivity through the evolution of the QCD medium and may reach local thermal equilibrium in Au+Au collisions at sNN−−−√=54.4 GeV. The measured eHF v2 in Au+Au collisions at sNN−−−√= 27 GeV is consistent with zero within large uncertainties. The energy dependence of v2 for different flavor particles (π,ϕ,D0/eHF) shows an indication of quark mass hierarchy in reaching thermalization in high-energy nuclear collisions.
Density fluctuations near the QCD critical point can be probed via an intermittency analysis in relativistic heavy-ion collisions. We report the first measurement of intermittency in Au+Au collisions at √sNN = 7.7-200 GeV measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). The scaled factorial moments of identified charged hadrons are analyzed at mid-rapidity and within the transverse momentum phase space. We observe a power-law behavior of scaled factorial moments in Au+Au collisions and a decrease in the extracted scaling exponent (ν) from peripheral to central collisions. The ν is consistent with a constant for different collisions energies in the mid-central (10-40%) collisions. Moreover, the ν in the 0-5% most central Au+Au collisions exhibits a non-monotonic energy dependence that reaches a minimum around √sNN = 27 GeV. The physics implications on the QCD phase structure are discussed.
Um Informationen zur Verbreitung und Populationsdichte von Stechmücken zu gewinnen, werden verschiedene Methoden verwendet. Neben der Suche nach Larven oder Puppen in den Brutgewässern, dem Absuchen von Ruheplätzen nach Adulten und den Fang aktiver, wirtssuchender Mückenweibchen durch freiwillige Mückenfänger werden vor allem unterschiedliche Fallentypen verwendet. Abgesehen von zwar preiswerten, aber wenig effizienten Fallen für gravide (also nicht mehr wirtsuchende) Mückenweibchen werden bisher Fallen mit unspezifische Lockreizen betrieben (Farbkontraste, Licht, Kohlendioxid). Letzteres ist in seiner Verwendung zudem aufwendig und teuer, da es aus Trockeneis, aus Gasflaschen oder der Verbrennung von Propangas freigesetzt werden muß. Wir stellen einen neuartigen Fallentypus für Stechmücken vor, den BG-Sentinel (Abb. 1). Die Falle wurde ursprünglich für die Überwachung der Gelbfiebermücke Stegomyia aegypti (ehemals Aedes aegypti, REINERT et al. 2004) entwickelt, ist aber auch für eine Reihe anderer Mücken attraktiv. Der BG-Sentinel ist die erste Falle, die neben visuellen Reizen auch, wie ein natürlicher Wirt, eine aufwärtsgerichtete Luftströmung produziert. Diese Luftströmung kann durch Zugabe geeigneter Düfte mit Lockstoffen beladen werden. Wir stellen außerdem mit der sogenannten BG-Lure einen neuen Mückenlockstoff vor, der aus Substanzen besteht, die auch auf der menschlichen Haut vorkommt. Die Konstruktion des BG-Sentinel ermöglicht es, eine Vielzahl verschiedener Reize auf ihre Attraktivität im Feld zu testen. Im Folgenden werden Feldtests des BG-Sentinel mit Stegomyia aegypti in Brasilien und Culex pipiens in Deutschland beschrieben.
We present the first measurement of fluctuations from event to event in the production of strange particles in collisions of heavy nuclei. The ratio of charged kaons to charged pions is determined for individual central Pb+Pb collisions. After accounting for the fluctuations due to detector resolution and finite number statistics we derive an upper limit on genuine non-statistical fluctuations, perhaps related to a first or second order QCD phase transition. Such fluctuations are shown to be very small.
Directed and elliptic flow of charged pions and protons in Pb + Pb collisions at 40 and 158 A GeV
(2003)
Directed and elliptic flow measurements for charged pions and protons are reported as a function of transverse momentum, rapidity, and centrality for 40 and 158A GeV Pb + Pb collisions as recorded by the NA49 detector. Both the standard method of correlating particles with an event plane, and the cumulant method of studying multiparticle correlations are used. In the standard method the directed flow is corrected for conservation of momentum. In the cumulant method elliptic flow is reconstructed from genuine 4, 6, and 8-particle correlations, showing the first unequivocal evidence for collective motion in A+A collisions at SPS energies.
It is demonstrated that there is no valid basis on which to sustain the monotypic genus Bathycranium Strobl and concluded that Bathycranium should be recognised as a junior synonym of Syntormon Loew (new status). The species Syntormon bicolorellus Zetterstedt (new combination) falls into a natural grouping of Syntormon species with downcurved facial hairs in females. This species and S. luteicornis Parent are redescribed. Distinctions between Syntormonand Parasyntormon are discussed.
Einleitung: Lokoregionäre Rezidivtumore der Kopf-Hals-Region können häufig nicht mehr kurativ operativ oder radiotherapeutisch behandelt werden, so dass neue Therapiekonzepte erforderlich sind. Es konnte gezeigt werden, dass statische Magnetfelder (SMF) Tumorwachstum und -angiogenese signifikant beeinflussen und zu einem intratumoralen Ödem führen. Das Ziel der vorliegenden Studie war die Evaluation des Effektes von SMF auf die Permeabilität von Tumorblutgefäßen und die therapeutische Nutzbarkeit in Kombination mit einer konventionellen Chemotherapie.
Methoden: Zellen eines syngenen amelanotischen Melanoms wurden in transparente Rückenhautkammern bei Goldhamstern implantiert. Unter SMF-Exposition von 587 mT wurde fluoreszenzmikroskopisch die Extravasation von rhodaminmarkiertem Albumin zur Errechnung der Gefäßpermeabilität gemessen und intratumorale Leukozyten-Endothelzell-Interaktionen quantifiziert. Für die anschließende Therapiestudie wurden die antitumoralen Effekte einer Kombinationstherapie von Paclitaxel und SMF-Exposition verglichen mit drei Kontrollgruppen (Glucose, Paclitaxel allein, SMF allein; je n=6).
Ergebnisse: SMF führen zu einer signifikanten Erhöhung der Tumorblutgefäßpermeabilität bei unveränderten Leukozyten-Endothelzell-Interaktionen. Die Kombinationstherapie von SMF und Paclitaxel ist – bezogen auf Tumorwachstum und Angiogenese – Monotherapien überlegen.
Schlussfolgerung: Eine SMF-induzierte Steigerung der Gefäßpermeabilität kann die Blut-Tumor-Schranke beeinflussen und somit die Effektivität einer Chemotherapie mit kleinmolekularen Substanzen wie Paclitaxel deutlich steigern. Bei Verwendung von Kopfspulen erscheint eine derartige adjuvante Kombinationstherapie für lokoregionäre Karzinomrezidive der Kopf-Hals-Region besonders geeignet.
In this study, we investigate the interaction of jets with their environment at a microscopic level, which is a key open question in the study of relativistic jets. Using small simulation systems during past research, we initially studied the evolution of both electron–proton and electron–positron relativistic jets containing helical magnetic fields, by focusing on their interactions with an ambient plasma. Here, using larger jet radii, we have performed simulations of global jets containing helical magnetic fields in order to examine how helical magnetic fields affect kinetic instabilities, such as the Weibel instability, the kinetic Kelvin–Helmholtz instability (kKHI) and the mushroom instability (MI). We found that the evolution of global jets strongly depends on the size of the jet radius. For example, phase bunching of jet electrons, in particular in the electron–proton jet, is mixed with a larger jet radius as a result of the more complicated structures of magnetic fields with excited kinetic instabilities. In our simulation, these kinetic instabilities led to new types of instabilities in global jets. In the electron–proton jet simulation, a modified recollimation occurred, and jet electrons were strongly perturbed. In the electron–positron jet simulation, mixed kinetic instabilities occurred early, followed by a turbulence-like structure. Simulations using much larger (and longer) systems are required in order to further thoroughly investigate the evolution of global jets containing helical magnetic fields.