Nonlinear coupling between scissors modes of a Bose-Einstein condensate

We explore the nonlinear coupling of the three scissors modes of an anisotropic Bose-Einstein condensate. We show that only when the frequency of one of the scissors modes is twice the frequency of another scissors mode, these two modes can be resonantly coupled and a down conversion can occur. We perform the calculation variationally using a gaussian trial wave function. This enables us to obtain simple analytical results that describe the oscillation and resonance behaviour of the two coupled modes.Comment: 12 pages, 3 figures, submitted to Phys. Rev.

Kinetic Theory of Collective Modes in Atomic Clouds above the Bose-Einstein Transition Temperature

We calculate frequencies and damping rates of the lowest collective modes of a dilute Bose gas confined in an anisotropic trapping potential above the Bose-Einstein transition temperature. From the Boltzmann equation with a simplified collision integral we derive a general dispersion relation that interpolates between the collisionless and hydrodynamic regimes. In the case of axially symmetric traps we obtain explicit expressions for the frequencies and damping rates of the lowest modes in terms of a phenomenological collision time. Our results are compared with microscopic calculations and experiments.Comment: Nordita preprint NORDITA-1999/46 C

Phase fluctuations in atomic Bose gases

We improve on the Popov theory for partially Bose-Einstein condensed atomic gases by treating the phase fluctuations exactly. As a result, the theory becomes valid in arbitrary dimensions and is able to describe the low-temperature crossover between three, two and one-dimensional Bose gases, which is currently being explored experimentally. We consider both homogeneous and trapped Bose gases.Comment: 4 pages. Title changed Major changes involve extension of theory to include trapped Bose gases. Deletion of reference to and comparison with hydrogen experiment. Due to these changes, second author added. Modified manuscript accepted for PR

Imaging and intervention for coronary artery disease following irradiation of malignant thymoma

Thymomas are rare malignant epithelial growths, constituting 20% of mediastinal tumours. Resection followed by irradiation may be employed in all thymomas except for stage 1 thymomas. Mediastinal irradiation is associated with coronary artery disease. The mean duration of presentation of post-irradiation coronary artery disease is 16 years (range 3-29 years). In our patient coronary artery disease was found only a year post irradiation. A 55 year old male who presented with complaints of dyspnoea, retrosternal chest pain and heaviness since one year underwent resection for malignant thymoma followed by radiotherapy. He presented with coronary artery disease a year after undergoing mediastinal irradiation. On follow-up, patient was treated successfully by coronary artery bypass graft. This case is an unusual occurrence and suggests that mediastinal irradiation may result in significant coronary artery disease as early as within one year

Benign granulomatous polyp obstructing the bronchus.

Abstract Inflammatory endobronchial polyps are rarely encountered. We report a case of a 14 years old girl with a benign granulomatous polyp originating in the bronchus. Computed tomography scan showed an intraluminal soft tissue opacity while fiberoptic bronchoscopy revealed a large soft tissue mass completely occluding the left lower lobe. Rigid bronchoscopy under general anaesthesia identified a fleshy mass in the left main stem bronchus which was excised via bronchoscopy. The histopathology showed benign polyp with non-specific inflammation. The patient\u27s symptoms improved subsequently and no recurrence was reported till two years of follow-u

Bright soliton trains of trapped Bose-Einstein condensates

We variationally determine the dynamics of bright soliton trains composed of harmonically trapped Bose-Einstein condensates with attractive interatomic interactions. In particular, we obtain the interaction potential between two solitons. We also discuss the formation of soliton trains due to the quantum mechanical phase fluctuations of a one-dimensional condensate.Comment: 4 pages, 2 figures, submitted to PR

Soliton response to transient trap variations

The response of bright and dark solitons to rapid variations in an expulsive longitudinal trap is investigated. We concentrate on the effect of transient changes in the trap frequency in the form of temporal delta kicks and the hyperbolic cotangent functions. Exact expressions are obtained for the soliton profiles. This is accomplished using the fact that a suitable linear Schrodinger stationary state solution in time can be effectively combined with the solutions of non-linear Schrodinger equation, for obtaining solutions of the Gross-Pitaevskii equation with time dependent scattering length in a harmonic trap. Interestingly, there is rapid pulse amplification in certain scenarios

Rast, sastav mesa i krvni pokazatelji kod prve generacije novih hibrida pilića i njihovih križanih roditelja.

A total of 2000 un-sexed day-old chicks of FIRI (Fayoumi male x RIR female), RLH (White Leghorn male x F1 female (Fayoumi male x RIR female) and RLH-G1 (generation one of RLH) chickens were obtained from the hatchery of the Poultry Research Institute, Rawalpindi. The chickens of each crossbred were divided into 5 groups as replicates under a completely randomized design, so that there were 400 chickens in each replicate. The birds were maintained on a deep litter system for a period of 20 weeks. The results showed that the average day-old weight was highest in RLH, intermediate in RLH-G1and lowest in FIRI chickens. The RLH-G1chickens consumed less (P0.05) dressing %age was observed in FIRI (62.60) followed by RLH (62.10) and RLH-G1 (61.98) chickens. The breast and thigh meat composition had a non-significant (P>0.05) difference of all crossbred chickens. There was a non-significant (P>0.05) difference in haematological values between all crossbred chickens. The total erythrocyte number, Hb and packed cell volume (PCV) increased with the advancement of age. However, the erythrocyte sedimentation rate (ESR), mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values decreased gradually with the advancement of age. It may be concluded that RLH and RLHG1crossbred chickens gained better body weight than FIRI chickens, with lower mortality. The first generation of RLH showed better FCR than RLH and FIRI crossbred chickens.U radu je korišteno ukupno 2000 jednodnevnih pilića, neodređenog spola, dobivenih iz valionice Instituta za istraživanje peradi u Ravalpindiju. S obzirom na roditelje, pilići su imali oznake FIRI (Fayoumi mužjaci x RIR ženke), RLH (mužjaci bijelog leghorna x F1 ženke (Fayoumi mužjaci x RIR ženke) i RLH-G1 (prva generacija RLH). Metodom slučajnog izbora pilići su podijeljeni u 5 skupina po 400 jedinki u svakoj skupini. Tijekom razdoblja od 20 tjedana, primijenjen je sustav držanja pilića na dubokoj prostirci. Rezultati su pokazali da je prosječna masa jednodnevnih pilića najveća u skupini RLH, zatim slijede pilići u RLH-G1, te pilići s najnižom prosječnom masom iz FIRI skupine. Pilići iz RLH-G1 skupine konzumirali su manje (P0,05) opažen je u skupini FIRI (62,60 %) pilića, slijedili su pilići RLH (62,10 %) i RLH-G1 (61,98 %) skupina. Sastav mesa prsa i bataka nije se signifikantno razlikovao (P>0,05) između pilića križanaca. Također, nesignifikantne (P>0,05) razlike između pilića utvrđene su i za sve krvne pokazatelje. Ukupni broj eritrocita, hemoglobin i hematokrit rasli su s porastom dobi pilića, dok su sedimentacija, prosječni volumen i prosječni hemoglobin eritrocita s porastom dobi postupno opadali. Može se zaključiti da su pilići križanci RLH i RLH-G1 skupina imali bolji prirast tjelesne mase u odnosu na piliće FIRI skupine koji su imali manju smrtnost. Prva generacija pilića iz RLH skupine pokazala je bolji FCR prirast nego pilići križanci RLH i FIRI skupina