2,854 research outputs found
The Isospin Asymmetry in Anomalous Fluid Dynamics
The dynamics of fluids in which the constituent particles carry nonabelian
charges can be described succinctly in terms of group-valued variables via a
generalization of the co-adjoint orbit action for particles. This formalism,
which is particularly suitable for incorporating anomalies, has previously been
used for the chiral magnetic and chiral vorticity effects. Here we consider the
similar effect for the isospin which corresponds to an angular asymmetry for
neutral pions.Comment: 12 page
Lingua Italiana e identità : Il caso del fumetto paninaro
From 1986 to 1989, Paninaro was the best selling comic magazine in Italy.Beside being a comic magazine, it represented also the link between identityand language in the second half of the 1980s. For the Italian youth, Paninaroserved as model of behaviour showing them how to talk, what to wear, how tolive. The language used in Paninaro was considered a sub-standard. The aimof this paper is to show how the paninaro’s language showed all thecharacteristics that later entered the Italian language from the1990s onward
Hygienic requirements of urban living environment in the Russian Federation and in Italy: a comparison
Introduzione/scopo. La pianificazione urbana tende a contenere e regolamentare la crescita urbana consentendo uno sviluppo sostenibile a livello ambientale, sociale e sanitario. Nel presente lavoro gli autori hanno confrontato i quadri normativi della Federazione Russ e dell’Italia ponendo particolare attenzione agli aspetti urbani degli spazi abitativi.
Metodo. Considerando la ponderosa produzione normativa nei due paesi, il lavoro ha preso in esame le normative a livello nazionale per l’Italia e federale per la Russia, tenendo principalmente conto dei seguenti aspetti: strumenti di pianificazione urbana e protezione ambientale e sanitaria degli spazi abitativi.
Risultati. I problemi relativi alla sicurezza igienico-sanitaria dell’ambiente di vita in Russia sono essenzialmente riconducibili a due sistemi normativi (SNiP e
SanPiN), mentre in Italia rientrano nel D.M. 05/07/1975. I principi fondamentali della pianificazione urbana in Russia sono dettati da una norma federale, mentre in
Italia sono recepiti nel Piano Regolatore Generale (PRG) comunale e nei diversi regolamenti locali, dove si riasriassume tutta la normativa sovraordinata. Gli aspetti legati alla qualità ambientale, infine, in entrambi i paesi sono disciplinati da varie leggi specifiche (federali e statali); un articolato sistema di norme che tengono conto dei
potenziali impatti sulla salute e sull’ambiente
Conclusioni. Gli autori ritengono che dovrebbero essere sviluppati, specialmente in Italia che si trova nettamente più indietro da questo punto di vista, strumenti normativi chiari e aggiornati aventi per oggetto l’igiene degli edifici e degli ambienti urbani, basati sulle più recenti acquisizioni di letteratura scientifica internazionale nell’intento di garantire i più alti standard in materia di tutela della Salute Pubblica.Aim. Urban planning tries to contain and regulate the uncontrolled growth of cities, encouraging their sustainable development at environmental, social and health levels. In the present work, the authors compare the regulatory frameworks of the Russian Federation and of Italy, with particular attention paid to the urban aspects of living spaces.
Method. Considering the extant normative production in the two countries, the authors examine national legislation for Italy and federal legislation for Russia, mainly taking into account the following aspects: urban planning tools and environmental and sanitary protection of living spaces.
Results. Hygienic-sanitary requirements regarding living environment in Russia are essentially expressed by two regulatory systems (SNiP and SanPiN), while in Italy they are regulated by the D.M. 07/05/1975. The main principles of urban planning in Russia are expressed by federal standards, while in Italy they are incorporated in the Municipal General Plan (PRG) and in the various local regulations, where all the superordinate regulations are summarized. Finally, aspects related to environmental quality in both countries are governed by various specific laws (federal and state); a complex system of rules that take into account potential impacts on health and the environment.
Conclusions. The authors reckon that clear and updated regulatory tools should be developed, especially in Italy that lags behind, regarding the building and urban hygiene, relying on the most recent acquisitions of international scientific literature in order to guarantee the highest standards in Public Health safeguard
Reply to "Comment on 'Precision measurement of the Casimir-Lifshitz force in a fluid'"
We have reviewed the Comment of Geyer et al. [arXiv:0708.1548] concerning our
recent work [Phys. Rev. A 75, 060102 (R) (2007)], and while we disagree with
their criticisms, we acknowledge them for giving us the opportunity to add
interesting addition material and a more detailed description of our
experiment. We describe further our calculation and explain why a more
sophisticated model is not warranted. We also present detailed experiments on
the effects of electrostatic forces in our measurements and show that the
contribution due to work function differences is small and that the residual
electrostatic force is dominated by trapped charges and external fields.
Finally, we estimate the effect of double layer interactions. These additional
calculations and measurements support our original conclusion that the
experimental results are consistent with the Lifshitz theory
Engineering Phonon Polaritons in van der Waals Heterostructures to Enhance In-Plane Optical Anisotropy
Van der Waals heterostructures assembled from layers of 2D materials have
attracted considerable interest due to their novel optical and electrical
properties. Here we report a scattering-type scanning near field optical
microscopy study of hexagonal boron nitride on black phosphorous (h-BN/BP)
heterostructures, demonstrating the first direct observation of in-plane
anisotropic phonon polariton modes in vdW heterostructures. Strikingly, the
measured in-plane optical anisotropy along armchair and zigzag crystal axes
exceeds the ratio of refractive indices of BP in the x-y plane. We explain that
this enhancement is due to the high confinement of the phonon polaritons in
h-BN. We observe a maximum in-plane optical anisotropy of {\alpha}_max=1.25 in
the 1405-1440 cm-1 frequency spectrum. These results provide new insights on
the behavior of polaritons in vdW heterostructures, and the observed anisotropy
enhancement paves the way to novel nanophotonic devices and to a new way to
characterize optical anisotropy in thin films
Achieving a Strongly Temperature-Dependent Casimir Effect
We propose a method of achieving large temperature sensitivity in the Casimir
force that involves measuring the stable separation between dielectric objects
immersed in fluid. We study the Casimir force between slabs and spheres using
realistic material models, and find large > 2nm/K variations in their stable
separations (hundreds of nanometers) near room temperature. In addition, we
analyze the effects of Brownian motion on suspended objects, and show that the
average separation is also sensitive to changes in temperature . Finally, this
approach also leads to rich qualitative phenomena, such as irreversible
transitions, from suspension to stiction, as the temperature is varied
Layered superconductors as negative-refractive-index metamaterials
We analyze the use of layered superconductors as anisotropic metamaterials.
Layered superconductors can have a negative refraction index in a wide
frequency range for arbitrary incident angles. Indeed, low-Tc (s-wave)
superconductors allow to produce artificial heterostructures with low losses
for T<<Tc. However, the real part of their in-plane effective permittivity is
very large. Moreover, even at low temperatures, layered high-Tc superconductors
have a large in-plane normal conductivity, producing large losses (due to
d-wave symmetry). Therefore, it is difficult to enhance the evanescent modes in
either low-Tc or high-Tc superconductors.Comment: 4 pages, 2 figure
Orientation-dependent Casimir force arising from highly anisotropic crystals: application to Bi2Sr2CaCu2O8+delta
We calculate the Casimir interaction between parallel planar crystals of Au
and the anisotropic cuprate superconductor Bi2Sr2CaCu2O8+delta (BSCCO), with
BSCCO's optical axis either parallel or perpendicular to the crystal surface,
using suitable generalizations of the Lifshitz theory. We find that the strong
anisotropy of the BSCCO permittivity gives rise to a difference in the Casimir
force between the two orientations of the optical axis, which depends on
distance and is of order 10-20% at the experimentally accessible separations 10
to 5000 nm.Comment: 5 pages, 3 figures. Accepted for publication in Physical Review
Horava-Lifshitz gravity: tighter constraints for the Kehagias-Sfetsos solution from new solar system data
We analytically work out the perturbation induced by the Kehagias-Sfetsos
(KS) space-time solution of the Horava-Lifshitz (HL) modified gravity at long
distances on the two-body range for a pair of test particles A and B orbiting
the same mass M. We apply our results to the most recently obtained
range-residuals \delta\rho for some planets of the solar system (Mercury, Mars,
Saturn) ranged from the Earth to effectively constrain the dimensionsless KS
parameter \psi_0 for the Sun. We obtain \psi_0 >= 7.2 x 10^-10 (Mercury),
\psi_0 >= 9 x 10^-12 (Mars), \psi_0 >= 1.7 x 10^-12 (Saturn). Such lower bounds
are tighter than other ones existing in literature by several orders of
magnitude. We also preliminarily obtain \psi_0 >= 8 x 10^-10 for the system
constituted by the S2 star orbiting the Supermassive Black Hole (SBH) in the
center of the Galaxy.Comment: LaTex2e, 15 pages, 1 table, 3 figures, 31 references. Version
matching the one at press in International Journal of Modern Physics D
(IJMPD
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