6,587 research outputs found
La guerre et les maladies vénériennes
Parmi toutes les misĂšres matĂ©rielles que la guerre mondiale a dĂ©chaĂźnĂ©es sur l'humanitĂ©, les ravages causĂ©s par le flĂ©au vĂ©nĂ©rien occupent une place considĂ©rable. En vĂ©ritĂ© nous ne somraes pas encore, aujourd'hui, en Ă©tat d'entrevoir les multiples rapports qui relient les maladies vĂ©nĂ©riennes Ă la guerre; il nous manque des donnĂ©es statistiques exactes portant sur le nombre total des soldats vĂ©nĂ©riens dans les diffĂ©rentes armĂ©es, et plus incomplĂštes encore sont nos connaissances sur l'extension des maladies vĂ©nĂ©riennes dans la population civile des pays belligĂ©rants. Incomplets aussi sont nos renseignements sur toutes les mesures prises par les diffĂ©rents pays et armees pour l'endiguement des maladies vĂ©nĂ©riennes, et surtout sur leurs rĂ©sultats favorables et dĂ©favorables. MalgrĂ© ces lacunes, les faits acquis par l'expĂ©rience sont si nombreux ct importants qu'ils doivent attirer l'attention de tout homme Ă qui l'avenir de l'humanitĂ© civilisĂ©e tient Ă cĆur. La guerre mondiale nous a montrĂ© que la lutte contre les maladies vĂ©nĂ©riennes est un problĂšme qui nĂ©cessite d'urgence une prompte solution. Elle a aussi modifiĂ© dans leur essence nos opinions sur les moyens les mieux appropriĂ©s Ă cette solution. Il y a lĂ , Ă cĂŽtĂ© de tous les maux et de toutes les tristesses que la guerre a semĂ©s, un bon grain Ă la germination duquel chaque peuple et chaque race sont intĂ©ressĂ©
On the significance of quantum effects and interactions for the apparent universality of Bloch laws for M_s(T)
The apparent universality of Bloch's T^{3/2}-law for the temperature
dependence of the spontaneous magnetization, and of generalizations thereof, is
considered. It is argued that in the derivation one should not only consider
the exchange interaction between the spins, but also the other interactions
between them, leading to elliptical spin precession and deviations from the
parabolic dispersion of magnons. Also interaction effects are important to
explain the apparent universality of generalized Bloch law exponents e_B,
defined by M_s(T)= M_s(0)-const. x T^{e_B}, valid in a wide temperature range
T_1 < T < T_2, and for dimensionalities d = 1, 2, and 3. The above-mentioned
temperature range, the 'Bloch range', lies above the quantum range, where
magnetic long-range order (e.g. in d=2 dimensions) is nontrivially enforced by
the additional interactions, but below the thermal critical region, where
universal 'anomalous scaling dimensions' apply. In contrast, for the Bloch
temperature region, the universality is only apparent, i.e. a
crossover-phenomenon, and simple scaling considerations with 'normal
dimensions' apply.
However, due to interactions, the Bloch exponent e_B depends not only on the
dimensionality d of the system, but also on the spin quantum number s (mod
(1/2)) of the system, i.e. for given d the Bloch exponent e_B is different for
half-integer s and for integer s.Comment: LATEX, 27 pages (including 5 eps-figures); accepted by JMM
Geometrically constrained magnetic wall
The structure and properties of a geometrically constrained magnetic wall in
a constriction separating two wider regions are investigated theoretically.
They are shown to differconsiderably from those of an unconstrained wall, so
that the geometrically constrained magnetic wall truly constitutes a new kind
of magnetic wall, besides the well known Bloch and Neel walls. In particular,
the width of a constrained wall cann become very small if the characteristic
length of the constriction is small, as is actually the case in an atomic point
contact. This provides a simple, natural explanation for the large
magnetoresistance observed in ferromagnetic atomic point contacts.Comment: RevTeX, 4 pages, 4 eps figures; v2: revised version; v3: ref. adde
Relatos do processo do meia metragem âO Ouro, O LadrĂŁo e Sua FamĂliaâ
Trabalho de conclusĂŁo de curso (graduação)âUniversidade de BrasĂlia, Instituto de Artes, Departamento de Artes CĂȘnicas, 2017.Esta monografia tem como objetivo relatar os principais eventos da trajetĂłria de um ano e meio do meia metragem âO Ouro, O LadrĂŁo e Sua FamĂliaâ dirigido por Leo Sykes, desde os primeiros desejos do que poderia ser, atĂ© as apresentaçÔes finais
CPV tests with rare kaon decays
The K_S \to pi+/- e+ e- decay mode has been investigated using the data
collected in 2002 by the NA48/1 collaboration. With about 23k signal events and
59k K_L \to pi+ pi- pi0_D normalization decays, the K_S \to pi+ pi- e+ e-
branching ratio was determined. This result is also used to set an upper limit
on the presence of E1 direct emission in the decay amplitude. The CP-violating
asymmetry has been also measured.
We report on measurements of the rare decays K +/- \to pi+/- e+ e- and K+/-
\to pi+/- mu+ mu- . The full NA48/2 data set was analyzed, leading to more than
7200 reconstructed events in the electronic and more than 3000 events in the
muonic channel, the latter exceeding the total existing statistics by a factor
of four. For both channels the selected events are almost background-free. From
these events, we have determined the branching fraction and form factors of
K+/- \to pi+/- e+ e- using different theoretical models. Our results improve
the existing world averages significantly. In addition, we measured the CP
violating asymmetry between K+ and K- in this channel to be less than a few
percent.Comment: 4 pages, 1 figure, To appear in the proceedings of IX International
Conference on Hyperons, Charm and Beauty Hadrons (BEACH2010), Perugia, Italy,
21-26 June 201
Intentional overdose with insulin: prognostic factors and toxicokinetic/toxicodynamic profiles
International audienc
Vortex stability and permanent flow in nonequilibrium polariton condensates
The following article appeared in Journal of Applied Physics 109.10 (2011): 102406 and may be found at http://scitation.aip.org/content/aip/journal/jap/109/10/10.1063/1.3576151We study the effects of imprinting a single-quantized vortex on the steady state of a microcavity exciton-polariton condensate generated via parametric scattering. Interestingly we observe two distinct regimes: In the first case, at low polariton densities, the effect of the pulsed probe, containing the vortex state, is to generate a gain response in the condensate lasting for tens of picoseconds during which no dissipation of the circulating currents is detected. In the second regime, at higher densities, the gain lasts much less and the circulation is imprinted directly into the steady state, which acquires permanent rotation for as long as the vortex remains within the condensate. We use two different ways of measuring the circulation of the condensate and demonstrate that in both cases, polariton condensation in the parametric scattering regime can sustain permanent supercurrentsThis work was partially supported by the Spanish MEC (MAT2008-01555 and QOIT-CSD2006-00019), the CAM (S2009/ESP-1503) and FP7 ITNs âClermont4â (235114). D.S. acknowledges financial support from the RamĂłn y Cajal program. G.T. is grateful for the FPI scholarship from the Ministerio de Ciencia e InnovaciĂł
Classes de cycles motiviques \'etales
Let X be a smooth variety over a field k, and l be a prime number invertible
in k. We study the (\'etale) unramified H^3 of X with coefficients Q_l/Z_l(2)
in the style of Colliot-Th\'el\`ene and Voisin. If k is separably closed,
finite or p-adic, this describes it as an extension of a finite group F by a
divisible group D, where F is the torsion subgroup of the cokernel of the
l-adic cycle map. If k is finite and X is projective and of abelian type,
verifying the Tate conjecture, D=0. If k is separably closed, we relate D to an
l-adic Griffiths group. If k is the separable closure of a finite field and X
comes from a variety over a finite field as described above, then D = 0 as soon
as H^3(X,Q_l) is entirely of coniveau > 0, but an example of Schoen shows that
this condition is not necessary.Comment: FInal version, to appear in Algebra and Number Theor
The Code of Protest. Images of Peace in the West German Peace Movements, 1945-1990
The article examines posters produced by the peace movements in the Federal Republic of
Germany during the ColdWar, with an analytical focus on the transformation of the iconography
of peace in modernity. Was it possible to develop an independent, positive depiction of peace
in the context of protests for peace and disarmament? Despite its name, the pictorial selfrepresentation
of the campaign âFight against Nuclear Deathâ in the late 1950s did not draw
on the theme of pending nuclear mass death. The large-scale protest movement in the 1980s
against NATOâs 1979 âdouble-trackâ decision contrasted female peacefulness with masculine
aggression in an emotionally charged pictorial symbolism. At the same time this symbolism
marked a break with the pacifist iconographic tradition that had focused on the victims of war.
Instead, the movement presented itself with images of demonstrating crowds, as an anticipation
of its peaceful ends. Drawing on the concept of asymmetrical communicative âcodesâ that has
been developed in sociological systems theory, the article argues that the iconography of peace in
peace movement posters could not develop a genuinely positive vision of peace, since the code of
protest can articulate the designation value âpeaceâ only in conjunction with the rejection value
âwarâ
Single-atom imaging of fermions in a quantum-gas microscope
Single-atom-resolved detection in optical lattices using quantum-gas
microscopes has enabled a new generation of experiments in the field of quantum
simulation. Fluorescence imaging of individual atoms has so far been achieved
for bosonic species with optical molasses cooling, whereas detection of
fermionic alkaline atoms in optical lattices by this method has proven more
challenging. Here we demonstrate single-site- and single-atom-resolved
fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas
microscope setup using electromagnetically-induced-transparency cooling. We
detected on average 1000 fluorescence photons from a single atom within 1.5s,
while keeping it close to the vibrational ground state of the optical lattice.
Our results will enable the study of strongly correlated fermionic quantum
systems in optical lattices with resolution at the single-atom level, and give
access to observables such as the local entropy distribution and individual
defects in fermionic Mott insulators or anti-ferromagnetically ordered phases.Comment: 7 pages, 5 figures; Nature Physics, published online 13 July 201
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