10,131 research outputs found
Practical Considerations Regarding the Preliminary Ruling Procedure Under Article 177 of the EEC Treaty
Part I of this Article considers the role played by the preliminary ruling procedure in the context of the Community legal system as a whole. Part II discusses the types of questions that may be appropriately referred to the Court for preliminary ruling. Part III examines the various tribunals and courts that may make a reference to the Court of Justice. Part IV analyzes the tension in the relationship between the Court and the national courts of the Member States. Finally, Part V considers the legal effects of preliminary rulings
Oblique propagation of solitary electrostatic waves in magnetized plasmas with cold ions and nonthermal electrons
Oblique propagation of large amplitude electrostatic waves and solitary structures is investigated in magnetized plasmas, comprising cold fluid ions and Cairns nonthermally distributed electrons, by using a Sagdeev pseudopotential formalism. To perform the analysis, quasineutrality is assumed, so that in normalized variables the electrostatic potential and the occurrence of solitary structures are governed by three parameters: the Mach number M, the typical Cairns parameter beta, and the angle theta between the directions of propagation and the static magnetic field. Below a critical beta, only positive compressive solitons are possible, and their amplitudes increase with increasing beta, M, and theta. Above the critical b, there is coexistence between negative rarefactive and positive compressive solitons, and the range of negative solitons, at increasing M, ends upon encountering a double layer or a singularity. The double layer amplitudes (in absolute value) increase with beta but are independent of theta. Roots of the Sagdeev pseudopotential beyond the double layer are not accessible from the undisturbed conditions, because of an intervening singularity where the pseudopotential becomes infinite. Recent claims of finding supersolitons beyond a double layer appear to be based on a misinterpretation of the nature of the singularity
Singular Fermi Surfaces II. The Two--Dimensional Case
We consider many--fermion systems with singular Fermi surfaces, which contain
Van Hove points where the gradient of the band function
vanishes. In a previous paper, we have treated the case of spatial dimension . In this paper, we focus on the more singular case and establish
properties of the fermionic self--energy to all orders in perturbation theory.
We show that there is an asymmetry between the spatial and frequency
derivatives of the self--energy. The derivative with respect to the Matsubara
frequency diverges at the Van Hove points, but, surprisingly, the self--energy
is in the spatial momentum to all orders in perturbation theory, provided
the Fermi surface is curved away from the Van Hove points. In a prototypical
example, the second spatial derivative behaves similarly to the first frequency
derivative. We discuss the physical significance of these findings.Comment: 68 pages LaTeX with figure
Properties of Heavy B Hadrons
We review recent measurements of heavy B hadron states including masses and
lifetimes of the Bc meson as well as excited B states (B**, Bs**). We discuss
properties of the Bs meson such as lifetime, lifetime difference
delta_Gamma/Gamma and CP violation in Bs -> J/Psi Phi decays. We also summarize
new measurements of the masses and lifetimes of bottom baryons including the
Lambda_b baryon, the Sigma_b baryon states as well as the Xi_b and Omega_b
baryons.Comment: Plenary talk at ICHEP08, Philadelphia, USA, July 2008. 15 pages with
10 figures and 1 table. Fixed typo
Head-on collisions of electrostatic solitons in nonthermal plasmas
In contrast to overtaking interactions, head-on collisions between two electrostatic solitons can only be dealt with by an approximate method, which limits the range of validity but offers valuable insights. Treatments in the plasma physics literature all use assumptions in the stretching of space and time and in the expansion of the dependent variables that are seldom if ever discussed. All models force a separability to lowest order, corresponding to two linear waves with opposite but equally large velocities. A systematic exposition of the underlying hypotheses is illustrated by considering a plasma composed of cold ions and nonthermal electrons. This is general enough to yield critical compositions that lead to modified rather than standard Korteweg-de Vries equations, an aspect not discussed so far. The nonlinear evolution equations for both solitons and their phase shifts due to the collision are established. A Korteweg-de Vries description is the generic conclusion, except when the plasma composition is critical, rendering the nonlinearity in the evolution equations cubic, with concomitant repercussions on the phase shifts. In the latter case, the solitons can have either polarity, so that combinations of negative and positive solitons can occur, contrary to the generic case, where both solitons necessarily have the same polarity
The Hydraenidae (Insecta: Coleoptera) of the Maltese Archipelago (Central Mediterranean)
The Hydraenidae of the Maltese Archipelago are reviewed, based on literature records and examination of historical and recently collected specimens. A total of eleven species is included of which Hydraena (s.str.) sub impressa REY, Ochthebius (s.str.) fossulatus MULSANT, O. (s.str.) punctatus STEPHENS, and O. (s.str.) viridis PEYRON (species complex) are recorded from the Maltese Islands for the first time. The records of the following four species by CAMERON & CARUANA GATTO (1907) are based on misidentifications:
Hydraena (s.str.) nigrita GERMAR (= H. (s.str.) subimpressa REY), Ochthebius (s.str.) foveolatus GERMAR (= O. (s.str.) eyrei JACH, and O. (s.str.) fossulatus MULSANT), O. (s.str.) lanuginosus REICHE & SAULCY (= O. (s.str.) punctatus STEPHENS), and O. (s.str.) sub integer MULSANT & REy (= O. (s.str.) celatus JACHpeer-reviewe
Multiple Steady States in Heterogeneous Azeotropic Distillation
In this article we study multiple steady states in ternary heterogeneous azeotropic distillation. We show that in the case of infinite reflux and an infinite number of trays one can construct bifurcation diagrams on physical grounds with the distillate flow as the bifurcation parameter. Multiple steady states exist when the distillate flow varies non-monotonically along the continuation path of the bifurcation diagram. We show how the distillate and bottom product paths can be located for tray or packed columns, with or without decanter and with different types of condenser and reboiler. We derive a necessary and sufficient condition for the existence of these multiple steady states based on the geometry of the product paths. We also locate in the composition triangle the feed compositions that lead to these multiple steady states. We show that the prediction of the existence of multiple steady states in the case of infinite reflux and an infinite number of trays has relevant implications for columns operating at finite reflux and with a finite number of trays
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