18,586 research outputs found
Jet Quenching in Heavy-Ion Collisions - The Transition Era from RHIC to LHC
A status report on the jet quenching physics in heavy-ion collisions is given
as it appears after more than 10 years of collecting and analysing data at the
Relativistic Heavy Ion Collider (RHIC) and ~1.5 years of physics at the Large
Hadron Collider (LHC). The (theoretical) predictions and expectations before
the start of the LHC program are contrasted with the most recent experimental
results, focussing on the nuclear modification factor R_{AA}, the elliptic flow
v_2 of high-p_T particles, and on the problem of initial conditions.Comment: 12 pages, 7 figures, review article in the "Topical Issue on
Relativistic Hydro- and Thermodynamics" EPJ
Justifying Inference to the Best Explanation as a Practical Meta-Syllogism on Dialectical Structures
This article discusses how inference to the best explanation (IBE) can be justified as a practical meta-argument. It is, firstly, justified as a *practical* argument insofar as accepting the best explanation as true can be shown to further a specific aim. And because this aim is a discursive one which proponents can rationally pursue in--and relative to--a complex controversy, namely maximising the robustness of one's position, IBE can be conceived, secondly, as a *meta*-argument. My analysis thus bears a certain analogy to Sellars' well-known justification of inductive reasoning (Sellars 1969); it is based on recently developed theories of complex argumentation (Betz 2010, 2011)
Revamping Hypothetico-Deductivism: A Dialectic Account of Confirmation
We use recently developed approaches in argumentation theory in order to revamp the hypothetico-deductive model of confirmation, thus alleviating the well-known paradoxes the H-D account faces. More specifically, we introduce the concept of dialectic confirmation on the background of the so-called theory of dialectical structures (Betz 2010, 2011). Dialectic confirmation generalises hypothetico-deductive confirmation and mitigates the raven paradox, the grue paradox, the tacking paradox, the paradox from conceptual difference, and the problem of novelty
Random permutations of a regular lattice
Spatial random permutations were originally studied due to their connections
to Bose-Einstein condensation, but they possess many interesting properties of
their own. For random permutations of a regular lattice with periodic boundary
conditions, we prove existence of the infinite volume limit under fairly weak
assumptions. When the dimension of the lattice is two, we give numerical
evidence of a Kosterlitz-Thouless transition, and of long cycles having an
almost sure fractal dimension in the scaling limit. Finally we comment on
possible connections to Schramm-L\"owner curves.Comment: 23 pages, 8 figure
Deflected Jets or Hot Spots? Conical Correlations of Hard Trigger Particles
The double-peak structure observed in soft-hard dihadron correlations was
recently studied intensively in order to learn more about the jet-induced
medium excitation in ultrarelativistic heavy-ion collisions. Experimental data
shows that the double-peak structure obtained for soft trigger particles
coalesces into one peak for harder trigger particles. We demonstrate that this
effect occurs when averaging over many jet events in a transversally expanding
background, while a hot spot scenario always leads to two distinct peaks. This
suggests to study soft-hard correlations induced by heavy-flavor jets with
those generated by light-flavor jets at RHIC and LHC in order to really
disentangle medium effects from jets.Comment: 6 pages, 3 figures, to appear in the proceedings of the Workshop on
'Hot & Cold Baryonic Matter 2010' (HCBM 2010), Budapest (Hungary
Ă–komorphologie : Integration von Form, Funktion und Ă–kologie bei der Analyse morphologischer Strukturen
Organisms are complex entities whose study has necessitated an increasingly reductionistic stance in modern biology (CAPLAN 1987). As a consequence, biology as a science has been split up into numerous sub-disciplines. However, this extremely reductionistic philosophy must not be taken as marking the endpoint of biological research but should be reappraised as the beginning of a new integrative approach encompassing the entire organism (SAUER 1992). This view has been promoted since the second half of the 20th century with the rise of new disciplines such as ecophysiology and ethoecology. Moreover, in morphology, an integrative approach with regard to the form and function of organisms in their relationship to the external environment is becoming increasingly important (e.g. KARR & JAMES 1975, MOTTA & KOTRSCHAL 1992, REILLY & WAINWRIGHT 1994).Aufgrund der enormen Komplexität von Organismen ist es in der heutigen Biologie unumgänglich geworden, mehr und mehr reduktionistische Ansätze zu verfolgen. Dies kommt in ihrer zunehmenden Zergliederung in Einzeldisziplinen zum Ausdruck. Extrem reduktionistische Ansätze dürfen jedoch nicht das Ende biologischer Forschung markieren, sondern sollten zugleich der Anfang für einen weiteren integrativen Ansatz sein, der das organismische Niveau berücksichtigt (vgl. SAUER, 1992). Auch in der Morphologie gewinnt eine integrative Sichtweise, welche die Form und Funktion morphologischer Strukturen in ihrer Beziehung zur externen Umwelt betrachtet, immer stärker an Bedeutung. Aufbauend auf klassischen morphologischen Disziplinen wie der deskriptiven und funktionellen Morphologie versteht man unter der ökologische Morphologie allgemein die Lehre von der Wechselbeziehung zwischen der Morphologie eines Organismus und seiner natürlichen Umwelt. Während die Funktionsmorphologie die Analyse exakter Struktur-Funktionsbeziehungen zum Inhalt hat, geht es in der Ökomorphologie um die Untersuchung der Funktion von Organismen im ökologischen (Umwelt) und/oder evolutionären Kontext (Historie), wodurch eine Förderung des Verständnisses der ökologischen und evolutionären Konsequenzen ihres Bauplanes erreicht werden soll. Dieses Forschungskonzept wird im Rahmen dieser Abhandlung anhand von Fallbeispielen vor allem aus der Gruppe der Staphylinoidea erläutert
What is the Relationship Between Altitude and Weight in a Model Rocket?
This experiment was designed to find a function of payload weight for altitude. The same rocket was launched a repeated number of times with the same engine and varying amounts of weight. After performing experimentation, it was calculated that the altitude in meters could be predicted with the equation A = (2.8(W exp 2)) - (70.6W + 310.3), with weight expressed in the unit ounces
Vortices and the related principles of hydrodynamics
Here, conceptions concerning vortices are illustrated by the simplest possible examples. Mathematical formulas and similar means of presentation, which, for the most part, do not help the understanding of persons not versed therein, have been avoided as much as possible. Instead, the author has endeavored to demonstrate the phenomena by means of simple geometrical and mechanical illustrations. For the sake of clarity, the author chiefly considers currents in one plane only, a situation that can be readily represented by diagrams. Some of the peculiarities of vortices in three dimensional flow are briefly discussed
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