The effect of many sources on the genuine multiparticle correlations

We report on a study aimed to explore the dependence of the genuine multiparticle correlations on the number of sources when the influence of other possible factors during multihadron production are avoided. The analysis utilised the normalised cumulants calculated in three-dimensional phase space of the reaction ee -> Z -> hadrons using a large Monte Carlo sample. The multi-sources events were simulated by overlaying a few independent single ee annihilation events. It was found that as the number of sources increases, the cumulants do not change significantly their structure, but those of an order higher than two decrease fast in their magnitude. This reduction and its amount can be understood in terms of combinatorial considerations of source mixing which dilutes the correlations. The diminishing of the genuine correlations is consistent with recent cumulant measurements in hadron and nucleus induced reactions and should also be relevant to other dynamical correlations like the Bose-Einstein one, in ee -> WW -> hadrons and in nucleus-nucleus reactions

The many sources effect on the genuine multihadron correlations

Here we report on a study aimed to explore the dependence of the genuine multiparticle correlations on the number of sources while the influence of other possible factors affecting the multihadron production is avoided. The analysis utilised the normalised cumulants, calculated in three-dimensional phase space, of the reaction e+e- -> Z -> hadrons using a large Monte Carlo event sample. The multi-sources reactions were simulated by overlaying a few independent single e+e- annihilation events. It was found that as the number of sources S increases, the cumulants do not change significantly their structure, but those of an order q>2 (i.e. more than 2 pions) decrease fast in their magnitude. This reduction can be understood in termsof combinatorial considerations of source mixing which dilutes the correlations by a factor of about 1/S^{q-1} which can also serve as a method to estimated the number of sources. This expected suppression is well reproduced by recent cumulant measurements in hadron and nucleus induced reactions both in one (rapidity) and two (rapidity vs. azimuthal angle) dimensions. The diminishing genuine correlations effect should also appear in other dynamical correlations like the Bose-Einstein in e+e- -> W+W- -> hadrons and in nucleus-nucleus reactions.Comment: 12 pages, 4 figs. Invited talk presented by G. Alexander at the 9th International Workshop on Multiparticle Production: New Frontiers in Soft Physics and Correlations on the Threshold of the Third Millenium, Turin, Italy, June 12 - 17, 200

Electrospun Ca3Co4−xO9+δ nanofibers and nanoribbons: Microstructure and thermoelectric properties

Oxide-based ceramics offer promising thermoelectric (TE) materials for recycling high-temperature waste heat, generated extensively from industrial sources. To further improve the functional performance of TE materials, their power factor should be increased. This can be achieved by nanostructuring and texturing the oxide-based ceramics creating multiple interphases and nanopores, which simultaneously increase the electrical conductivity and the Seebeck coefficient. The aim of this work is to achieve this goal by compacting electrospun nanofibers of calcium cobaltite Ca3Co4−xO9+δ, known to be a promising p-type TE material with good functional properties and thermal stability up to 1200 K in air. For this purpose, polycrystalline Ca3Co4−xO9+δ nanofibers and nanoribbons were fabricated by sol–gel electrospinning and calcination at intermediate temperatures to obtain small primary particle sizes. Bulk ceramics were formed by sintering pressed compacts of calcined nanofibers during TE measurements. The bulk nanofiber sample pre-calcined at 973 K exhibited an improved Seebeck coefficient of 176.5 S cm−1 and a power factor of 2.47 μW cm−1 K−2 similar to an electrospun nanofiber-derived ceramic compacted by spark plasma sintering

Vorgehen zur Einführung von Community Systemen in Lerngemeinschaften

Aus der Einleitung: 'Die Diskussion um den Einsatz der „Neuen Medien“ im Bildungsbereich wird in zwei Richtungen geführt: Neben der multimedialen Aufbereitung von Lemmaterialien in Lemprogrammen oder Präsentationen, die im Rahmen herkömmlicher Lehrveranstaltungen eingesetzt werden können, sollen virtuelle Lehrveranstaltungen örtlich und zeitlich flexibles Lernen ermöglichen. Der Einsatz von Community Systemen bietet die Chance, die positiven Aspekte beider Ausprägungen zu verbinden. Als Community System bezeichnen wir eine netzbasierte Computerunterstützung für eine thematisch fokussierte Benutzergruppe. Ein Community System ermöglicht den aktiven Umgang mit einer Vielfalt von elektronischen Dokumenten und Materialien und unterstützt darüber hinaus insbesondere die Kommunikation der Beteiligten in verschiedenen Formen

Mass and Transverse Mass Effects on the Hadron Emitter Size

We investigate the dependence of the longitudinal emitter dimension of identical bosons, produced in the hadronic Z$^0$ decays, on their transverse mass obtained from 2-dimensional Bose-Einstein correlations (BEC) analyses. We show that this dependence is well described by the expression $r_{||}=c\sqrt{\hbar\Delta t}/\sqrt{m_T}$, deduced from the uncertainty relations, setting $\Delta t$ to be a constant of the order of $10^{-24}$ sec. This equation is essentially identical to the one previously applied to the 1-dimensional BEC results for the emitter radius dependence on the boson mass itself. It is further shown that a very similar behaviour exists also for the dependence of the interatomic separation in Bose condensates on their atomic masses when they are at the same very low temperature.Comment: 10 pges, 2 figure

No positive effect of autologous platelet gel after total knee arthroplasty: A double-blind randomized controlled trial: 102 patients with a 3-month follow-up

Background and purpose Activated platelets release a cocktail of growth factors, some of which are thought to stimulate repair. We investigated whether the use of autologous platelet gel (PG) in total knee arthroplasty (TKA) would improve wound healing and knee function, and reduce blood loss and the use of analgesics. Patients and methods 102 patients undergoing TKA were randomly assigned to a PG group (n 50) or to a control (C) group (n 52). The primary analysis was based on 73 participants (PG: 32; C: 41) with comparison of postoperative wound scores, VAS, WOMAC, knee function, use of analgesics, and the pre- and postoperative hemoglobin values after a follow-up of 3 months. 29 participants were excluded due to insufficient data. Results The characteristics of the protocol-compliant patients were similar to those of the patients who w

Exploring, exploiting and evolving diversity of aquatic ecosystem models: A community perspective

Here, we present a community perspective on how to explore, exploit and evolve the diversity in aquatic ecosystem models. These models play an important role in understanding the functioning of aquatic ecosystems, filling in observation gaps and developing effective strategies for water quality management. In this spirit, numerous models have been developed since the 1970s. We set off to explore model diversity by making an inventory among 42 aquatic ecosystem modellers, by categorizing the resulting set of models and by analysing them for diversity. We then focus on how to exploit model diversity by comparing and combining different aspects of existing models. Finally, we discuss how model diversity came about in the past and could evolve in the future. Throughout our study, we use analogies from biodiversity research to analyse and interpret model diversity. We recommend to make models publicly available through open-source policies, to standardize documentation and technical implementation of models, and to compare models through ensemble modelling and interdisciplinary approaches. We end with our perspective on how the field of aquatic ecosystem modelling might develop in the next 5–10 years. To strive for clarity and to improve readability for non-modellers, we include a glossary