998 resultados para course description
Resumo:
A pseudoclassical model for a spinning nonrelativistic particle is presented. The model contains two first-class constraints which after quantization give rise to the Levy-Leblond equation for a spin-1/2 particle.
Resumo:
A pseudoclassical model for a relativistic spinning particle is studied. The only physically meaningful world line is the one without Zitterbewegung. The Poincar realization for this situation is constructed.
Resumo:
We investigate the "twist" mode (rotation of the upper against the lower hemisphere) of a dilute atomic Fermi gas in a spherical trap. The normal and superfluid phases are considered. The linear response to this external perturbation is calculated within the microscopic Hartree-Fock-Bogoliubov approach. In the normal phase the excitation spectrum is concentrated in a rather narrow peak very close to the trapping frequency. In the superfluid phase the strength starts to be damped and fragmented and the collectivity of the mode is progressively lost when the temperature decreases. In the weak-pairing regime some reminiscence of the collective motion still exists, whereas in the strong-pairing regime the twist mode is completely washed out. The disappearance of the twist mode in the strong-pairing regime with decreasing temperature is interpreted in the framework of the two-fluid model.
Resumo:
Comprend : [Fig. p.1 : groupe de randonneurs dans les montagnes Suisses du Canton de Berne.] [Cote : Res g M 23/Microfilm R 122251] ; [Fig. après p.15 : carte et vue des montagnes de la Suisse. Canton de Berne. Le Mont Jungfrau, le Moench, le Grofshorn, le ruisseau Schmadribach, le Bietenhorn...] [Cote : Res g M 23/Microfilm R 122251] ; [Pl.1 après p.15 :] Breitlauwiren, contre le glacier du Breithorn. [Cote : Res g M 23/Microfilm R 122251] ; [Pl.2 après p.15 :] Vallée de Lauterbrounn, contre les glaciers du Canton de Berne. [Cote : Res g M 23/Microfilm R 122251] ; [Pl.3 après p.15 :] Schiltwaldbac en hyver vis-à-vis du Staubbach (...). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.4 après p.15 :] Première chûte du Staubbach (...). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.5 après p.15 :] Seconde chûte du Staubbach (...). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.6 après p.15 :] Seconde chûte du Staubbach en hyver (...). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.7 après p.15 :] Glacier du Breithorn contre le couchant. [Cote : Res g M 23/Microfilm R 122251] ; [Pl.8 après p.15 :] Chûte du Myrrenbach (... ). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.9 après p.15 :] Glacier du Breithorn (.. .). [Cote : Res g M 23/Microfilm R 122251] ; [Pl.10 après p.15 :] Herrenbaechlé (...). [Cote : Res g M 23/Microfilm R 122251]
Resumo:
With a life expectancy at the age of 65 of around 20 years, damaging health risk behaviours of young-old adults have become a target for preventive actions. Such risk factors necessitate an accurate understanding of the present and past socioeconomic conditions associated with health risk behaviours. The aim of our study is to assess the impact of certain life events as well as economic and environmental factors on health risk behaviours. We included 1309 participants of the Lausanne Cohort Lc65+ aged 65-70 years and employed logistic regression analyses, with individuals nested within areas. The results illustrate the influences of socioeconomic factors from childhood to young-old age. Life experiences in adulthood and economic resources in young-old age are both associated with unfavourable health behaviours. Neighbourhood is a modest determinant as well, particularly regarding alcohol consumption. Therefore, prevention against health risk behaviours should focus on population subgroups defined on the basis of their socioeconomic and living contexts.
Resumo:
Selostus: Kolmen uuden mesimarjalajikkeen kuvaukset ja lajikekuvausohjeet mesimarjalle ja jalomaaraimelle
Resumo:
We conducted a molecular study of MRSA isolated in Swiss hospitals, including the first five consecutive isolates recovered from blood cultures and the first ten isolates recovered from other sites in newly identified carriers. Among 73 MRSA isolates, 44 different double locus sequence typing (DLST) types and 32 spa types were observed. Most isolates belonged to the NewYork/Japan, the UK-EMRSA-15, the South German and the Berlin clones. In a country with a low to moderate MRSA incidence, inclusion of non-invasive isolates allowed a more accurate description of the diversity.
Resumo:
We extend the recent microscopic analysis of extremal dyonic Kaluza-Klein (D0-D6) black holes to cover the regime of fast rotation in addition to slow rotation. Fastly rotating black holes, in contrast to slow ones, have nonzero angular velocity and possess ergospheres, so they are more similar to the Kerr black hole. The D-brane model reproduces their entropy exactly, but the mass gets renormalized from weak to strong coupling, in agreement with recent macroscopic analyses of rotating attractors. We discuss how the existence of the ergosphere and superradiance manifest themselves within the microscopic model. In addition, we show in full generality how Myers-Perry black holes are obtained as a limit of Kaluza-Klein black holes, and discuss the slow and fast rotation regimes and superradiance in this context.
Resumo:
The physical contributions to the KNiF3 magnetic exchange coupling integral have been obtained from specially designed ab initio cluster model calculations. Three important mechanisms have been identified. These are the delocalization of the magnetic orbitals into the anion p band, the variational contribution of the second-order interactions, and the many-body terms hidden in the two-body operator and the Heisenberg Hamiltonian.
Resumo:
Liver vascularization is known to present with several different variations. Generally, a normal vascular anatomy is reported in up to 50-80 % of cases. For this reason, a precise preoperative mapping of the hepatic vascularization prior to pancreatic surgery is essential to avoid injuries and subsequent complications. We report here a case of a young patient scheduled for Whipple procedure, who presented an arterial pattern type Michels IV, variation reported in 0.6 to 3 % in the literature. Another interesting particularity of this case was the fact that the right hepatic artery had a prepancreatic course. We think that every surgeon performing hepatopancreatic surgery should have heard of this special and rare situation.
Resumo:
We compared specimens of Tripterygion tripteronotus from 52 localities of the Mediterranean Sea and adjacent waters, using four gene sequences (12S rRNA, tRNA-valine, 16S rRNA and COI) and morphological characters. Two well-differentiated clades with a mean genetic divergence of 6.89±0.73% were found with molecular data, indicating the existence of two different species. These two species have disjunctive geographic distribution areas without any molecular hybrid populations. Subtle but diagnostic morphological differences were also present between the two species. T. tripteronotus is restricted to the northern Mediterranean basin, from the NE coast of Spain to Greece and Turkey, including the islands of Malta and Cyprus. T. tartessicum n. sp. is geographically distributed along the southern coast of Spain, from Cape of La Nao to the Gulf of Cadiz, the Balearic Islands and northern Africa, from Morocco to Tunisia. According to molecular data, these two species could have diverged during the Pliocene glaciations 2.7-3.6 Mya.
Resumo:
To evaluate the various factors influencing the stability of granular base course mixes, three primary goals were included in the project: (1) determination of a suitable and realistic laboratory method of compaction; (2) effect of gradation, density and mineralogy of the fines on sheara ing strength; and (3) possible improvement of the shear strength with organic and inorganic chemical stabilization additives.