Quantum critical 5f-electrons avoid singularities in U(Ru,Rh)2Si2

We present specific heat measurements of 4% Rh-doped U(Ru,Rh)2Si2 at magnetic fields above the proposed metamagnetic transition field Hm~34 T, revealing striking similarities to the isotructural Ce analog CeRu2Si2, suggesting that strongly renormalized hybridized band models apply equally well to both systems. The vanishing bandwidths as H --> Hm are consistent with a putative quantum critical point close to Hm. The existence of a phase transition into an ordered phase in the vicinity of Hm for 4% Rh-doped U(Ru,Rh)2Si2, but not for CeRu2Si2, is consistent with a stronger super-exchange in the case of the U 5-f system, with irreversible processes at the transition revealing a strong coupling of the 5f orbitals to the lattice, most suggestive of orbital or electric quadrupolar order.Comment: 4 pages, 4 figure

Ferrotoroidic Moment as a Quantum Geometric Phase

We present a geometric characterization of the ferrotoroidic moment in terms of a set of Abelian Berry phases. We also introduce a fundamental complex quantity which provides an alternative way to calculate the ferrotoroidic moment and its moments, and is derived from a second order tensor. This geometric framework defines a natural computational approach for density functional and many-body theories

Electron Spin Resonance of defects in the Haldane System Y(2)BaNiO(5)

We calculate the electron paramagnetic resonance (EPR) spectra of the antiferromagnetic spin-1 chain compound Y(2)BaNi(1-x)Mg(x)O(5) for different values of x and temperature T much lower than the Haldane gap (~100K). The low-energy spectrum of an anisotropic Heisenberg Hamiltonian, with all parameters determined from experiment, has been solved using DMRG. The observed EPR spectra are quantitatively reproduced by this model. The presence of end-chain S=1/2 states is clearly observed as the main peak in the spectrum and the remaining structure is completely understood.Comment: 5 pages, 4 figures include

Infestação natural de piolhos em búfalos.

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Endometriosis-induced intussusception of the caecal appendix

Appendicular intussusception is an uncommon entity, with a reported incidence of 0.01%. The diagnosis is difficult and often only performed at the time of surgery. Intussusception has multiple causes including tumours, foreign bodies and polyps. The definitive treatment is surgical, and the extent of resection is determined by the underlying pathology and degree of invagination. Endometriosis is a rare cause of appendicular intussusception, with 194 cases described in the English literature. We report a case of a 42-year-old woman who presented with chronic abdominal pain in the lower right quadrant. A mass at the caecum was identified during investigations for renal stones by CT. Colonoscopy showed a polypoid lesion, with presumed origin in the appendix. Ileocaecal resection was performed because an appendicular tumour was suspected. Pathological examination identified endometriosis of the appendix and associated peritoneum with invagination of the caecum. The patient was discharged 7 days after surgery and is currently asymptomatic

Stick-Slip Motion and Phase Transition in a Block-Spring System

We study numerically stick slip motions in a model of blocks and springs being pulled slowly. The sliding friction is assumed to change dynamically with a state variable. The transition from steady sliding to stick-slip is subcritical in a single block and spring system. However, we find that the transition is continuous in a long chain of blocks and springs. The size distribution of stick-slip motions exhibits a power law at the critical point.Comment: 8 figure

Efeito de diferentes métodos de eliminação do resíduo pós-pastejo na produção e valor nutritivo do capim andropógon (Andropogon gayanus).

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Teores de minerais do capim canarana-erecta-lisa (Echinochloa pyramidalis) em três idades.

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Digestibilidade "in vivo" dos constituintes da parede celular do capim quicuio-da-amazônia (Brachiaria humidicola (Rendle) Schweickerdt).

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