Vortex-Peierls States in Optical Lattices

We show that vortices, induced in cold atom superfluids in optical lattices, may order in a novel vortex-Peierls ground state. In such a state vortices do not form a simple lattice but arrange themselves in clusters, within which the vortices are partially delocalized, tunneling between classically degenerate configurations. We demonstrate that this exotic quantum many-body state is selected by an order-from-disorder mechanism for a special combination of the vortex filling and lattice geometry that has a macroscopic number of classically degenerate ground states.Comment: 4 pages, 4 figures. Published versio

Dynamical evolution of a doubly-quantized vortex imprinted in a Bose-Einstein Condensate

The recent experiment by Y. Shin \emph{et al.} [Phys. Rev. Lett. \textbf{93}, 160406 (2004)] on the decay of a doubly quantized vortex imprinted in $^{23}$Na condensates is analyzed by numerically solving the Gross-Pitaevskii equation. Our results, which are in very good quantitative agreement with the experiment, demonstrate that the vortex decay is mainly a consequence of dynamical instability. Despite apparent contradictions, the local density approach is consistent with the experimental results. The monotonic increase observed in the vortex lifetimes is a consequence of the fact that, for large condensates, the measured lifetimes incorporate the time it takes for the initial perturbation to reach the central slice. When considered locally, the splitting occurs approximately at the same time in every condensate, regardless of its size.Comment: 5 pages, 4 figure

Phase Separation of a Fast Rotating Boson-Fermion Mixture in the Lowest-Landau-Level Regime

By minimizing the coupled mean-field energy functionals, we investigate the ground-state properties of a rotating atomic boson-fermion mixture in a two-dimensional parabolic trap. At high angular frequencies in the mean-field-lowest-Landau-level regime, quantized vortices enter the bosonic condensate, and a finite number of degenerate fermions form the maximum-density-droplet state. As the boson-fermion coupling constant increases, the maximum density droplet develops into a lower-density state associated with the phase separation, revealing characteristics of a Landau-level structure

Phases of a rotating Bose-Einstein condensate with anharmonic confinement

We examine an effectively repulsive Bose-Einstein condensate of atoms that rotates in a quadratic-plus-quartic potential. With use of a variational method we identify the three possible phases of the system (multiple quantization, single quantization, and a mixed phase) as a function of the rotational frequency of the gas and of the coupling constant. The derived phase diagram is shown to be universal and the continuous transitions to be exact in the limit of weak coupling and small anharmonicity. The variational results are found to be consistent with numerical solutions of the Gross-Pitaevskii equation.Comment: 8 pages, 6 figure

Discriminant analysis for the prediction and classification of tick-borne infections in some dairy cattle herds at Dakahlia Governorate, Egypt

This study was undertaken to use the variable loadings in linear discriminant analysis (LDA) to determine the most important predictors for the discrimination of tick-borne diseases (TBDs), particularly babesiosis and anaplasmosis and predict the group membership from the predictors. In total, 163 cattle, from different localities at Dakahlia Governorate, Egypt, were investigated in 2012 and 2013 for the presence of TBDs. All cattle were clinically examined and a clinical index score was determined for each cow. Blood samples were also collected from each animal for adopting microscopy and diagnostic laboratory methods. Out of the examined cattle, 83 animals were acutely-ill (Babesia bovis and Anaplasma marginale were identified in 11 and 10 animals, respectively), while 80 cows were apparently healthy but having previous attacks of blood parasites (23 animals harbored anaplasma marginale (asymptomatic carriers)). The remained 119 animals were negative to TBDs. Fourteen animals were not survived and 149 cases were survived. As the result of the first LDA to discriminate babesiosis, anaplasmosis and negative to TBDs, 89.0% of animals were correctly classified; 78.8% (26/33) for anaplasma, 100% (11/11) for babesia infections, 90.8% (108/119) for negative to TBDs, respectively. The important predictors for the discrimination were oculonasal discharge, bloody feces, hemoglobinuria, bloody feces and respiratory rate. On the other hand, the second LDA discrimination showed high classification accuracy of 87.1% for the discrimination of survivors and non-survivors; 89.9% (134/149) for survivors and 57.1% (8/14) for non-survivors, while the important predictors included oculonasal discharge, recumbent posture and nervous sign

Infundebulectomy in management of uterine artery or uterine wall injury during complicated and difficult caesarean section: case series study

It is case series trying to save uterus in situation where one site of it is severely injured or in severe uncontrollable bleeding in one of the uterine arteries either during control of massive hemorrhage associated with friable tissues with severe adhesion, some cases of placenta accrete spectrum, some cases of uterine rupture and in caesarean section myomectomy

Observation of Vortex Pinning in Bose-Einstein Condensates

We report the observation of vortex pinning in rotating gaseous Bose-Einstein condensates (BEC). The vortices are pinned to columnar pinning sites created by a co-rotating optical lattice superimposed on the rotating BEC. We study the effects of two different types of optical lattice, triangular and square. With both geometries we see an orientation locking between the vortex and the optical lattices. At sufficient intensity the square optical lattice induces a structural cross-over in the vortex lattice.Comment: 4 pages, 6 figures. Replaced by final version to appear in Phys. Rev. Let

Nonequilibrium effects of anisotropic compression applied to vortex lattices in Bose-Einstein condensates

We have studied the dynamics of large vortex lattices in a dilute-gas Bose-Einstein condensate. While undisturbed lattices have a regular hexagonal structure, large-amplitude quadrupolar shape oscillations of the condensate are shown to induce a wealth of nonequilibrium lattice dynamics. When exciting an m = -2 mode, we observe shifting of lattice planes, changes of lattice structure, and sheet-like structures in which individual vortices appear to have merged. Excitation of an m = +2 mode dissolves the regular lattice, leading to randomly arranged but still strictly parallel vortex lines.Comment: 5 pages, 6 figure

Role of Latissimus Dorsi Island Flap in Coverage of Mutilating Upper Limb Injuries in Pediatric Age Group

Background/Purpose: Latissimus dorsi muscle (LDM) is one of the most versatile muscles that is commonly used in different reconstructive procedures. Severe mutilating injuries of the upper limb in children represent a great challenge to reconstructive surgeons especially when important structures become exposed. Materials & Methods: we utilized LDM as an island flap to cover extensive soft tissue defects in the upper limb of pediatric patients. This work included 17 children (13 males and 4 females). All of them had extensive soft tissue loss of the upper limb with exposure of important structures. The cause of injury was road traffic accident in all patients. We analyzed the operative time, need for multi-stage surgery and the recorded complications. Finally, we recorded the ultimate functional and aesthetic outcome after a period of two years of follow up. Results: From the harvested seventeen flaps, none of them was lost. Split thickness skin graft was done one week after flap harvesting and insetting to cover the muscle flap. There were four cases with partial loss of the skin graft secondary to infection. Those four cases needed re-grafting after eradication of infection that needed almost two weeks of local wound care and dressing. Re-grafting was successful in the four cases. Conclusion: For complex upper extremity wounds in the pediatric age group, we advice aggressive debridement and early reconstruction with LDM pedicle flap with a split-thickness skin graft cover over it. The technique is reliable, with minimal donor site morbidity and very accepted functional and cosmetic outcome.Index Word: Latissimus dorsi muscle flap, complex trauma, pediatric age group