7,127 research outputs found
Systematics of Stopping and Flow in Au+Au Collisions
Excitation functions of flow and stopping observables for the Au+Au system at
energies from 40 to 1500 MeV per nucleon are presented. The systematics were
obtained by merging the results of the INDRA and FOPI experiments, both
performed at the GSI facility. The connection to the nuclear equation of state
is discussed.Comment: Contribution to the WCI book "Dynamics and Thermodynamics with
Nucleonic Degrees of Freedom
Collective flow in heavy ion collisions at intermediate energies
We present results of a flow analysis for the set of reactions of 124,129Xe
projectiles and 112,124Sn targets at incident energies 100 and 150 A MeV
studied with the INDRA detector at GSI. The dependence on centrality and on p_t
of the directed and elliptic flow are determined for isotopically selected
reaction products with Z \le 3. The flow parameters v_1 and v_2, in general,
follow expected trends but isotopic effects are small.Comment: 3 pages, 2 figures, contributed talk at INPC, Tokyo, June 3-8, 2007,
to appear in the proceeding
Classifying Tweet Level Judgements of Rumours in Social Media
Social media is a rich source of rumours and corresponding community
reactions. Rumours reflect different characteristics, some shared and some
individual. We formulate the problem of classifying tweet level judgements of
rumours as a supervised learning task. Both supervised and unsupervised domain
adaptation are considered, in which tweets from a rumour are classified on the
basis of other annotated rumours. We demonstrate how multi-task learning helps
achieve good results on rumours from the 2011 England riots
Firefly Algorithm, Stochastic Test Functions and Design Optimisation
Modern optimisation algorithms are often metaheuristic, and they are very
promising in solving NP-hard optimization problems. In this paper, we show how
to use the recently developed Firefly Algorithm to solve nonlinear design
problems. For the standard pressure vessel design optimisation, the optimal
solution found by FA is far better than the best solution obtained previously
in literature. In addition, we also propose a few new test functions with
either singularity or stochastic components but with known global optimality,
and thus they can be used to validate new optimisation algorithms. Possible
topics for further research are also discussed.Comment: 12 pages, 11 figure
Space and Time pattern of mid-velocity IMF emission in peripheral heavy-ion collisions at Fermi energies
The emission pattern in the V_perp - V_par plane of Intermediate Mass
Fragments with Z=3-7 (IMF) has been studied in the collision 116Sn + 93Nb at
29.5 AMeV as a function of the Total Kinetic Energy Loss of the reaction. This
pattern shows that for peripheral reactions most of IMF's are emitted at
mid-velocity. Coulomb trajectory calculations demonstrate that these IMF's are
produced in the early stages of the reaction and shed light on geometrical
details of these emissions, suggesting that the IMF's originate both from the
neck and the surface of the interacting nuclei.Comment: 4 pages, 3 figures, RevTex 3.1, submitted to Phys. Rev. Letter
Comparison of molecular markers to detect fresh sewage in environmental waters
Human-specific Bacteroides HF183 (HS-HF183), human-specific Enterococci faecium esp (HS-esp), human-specific adenoviruses (HS-AVs) and human-specific polyomaviruses (HS-PVs) assays were evaluated in freshwater, seawater and distilled water to detect fresh sewage. The sewage spiked water samples were also tested for the concentrations of traditional fecal indicators (i.e., Escherichia coli, enterococci and Clostridium perfringens) and enteric viruses such as enteroviruses (EVs), sapoviruses (SVs), and torquetenoviruses (TVs). The overall host-specificity of the HS-HF183 marker to differentiate between humans and other animals was 98%. However, the HS-esp, HS-AVs and HS-PVs showed 100% hostspecificity. All the human-specific markers showed >97% sensitivity to detect human fecal pollution. E. coli, enterococci and, C. perfringens were detected up to dilutions of sewage 10_5, 10_4 and 10_3 respectively.HS-esp, HS-AVs, HS-PVs, SVs and TVs were detected up to dilution of sewage 10_4 whilst EVs were detected up to dilution 10_5. The ability of the HS-HF183 marker to detect freshsewagewas3â4 orders ofmagnitude higher than that of the HS-esp and viral markers. The ability to detect fresh sewage in freshwater, seawater and distilled water matrices was similar for human-specific bacterial and viral marker. Based on our data, it appears that human-specific molecular markers are sensitive measures of fresh sewage pollution, and the HS-HF183 marker appears to be the most sensitive among these markers in terms of detecting fresh sewage. However, the presence of the HS-HF183 marker in environmental waters may not necessarily indicate the presence of enteric viruses due to their high abundance in sewage compared to enteric viruses. More research is required on the persistency of these markers in environmental water samples in relation to traditional fecal indicators and enteric pathogens
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