18,436 research outputs found
Anisotropic fluid inside a relativistic star
An anisotropic fluid with variable energy density and negative pressure is
proposed, both outside and inside stars. The gravitational field is constant
everywhere in free space (if we neglect the local contributions) and its value
is of the order of , in accordance with MOND model. With
, the acceleration is also constant inside stars but the
value is different from one star to another and depends on their mass and
radius . In spite of the fact that the spacetime is of Rindler type and
curved even far from a local mass, the active gravitational energy on the
horizon is , as for the flat Rindler space, excepting the negative sign.Comment: 9 pages, refs added, new chapter added, no figure
Unidimensional reduction of the 3D Gross-Pitaevskii equation with two- and three-body interactions
We deal with the three-dimensional Gross-Pitaevskii equation, which is used
to describe a cloud of dilute bosonic atoms that interact under competing two-
and three-body scattering potentials. We study the case where the cloud of
atoms is strongly confined in two spatial dimensions, allowing us to build an
unidimensional nonlinear equation, controlled by the nonlinearities and the
confining potentials that trap the system along the longitudinal coordinate. We
focus attention on specific limits, dictated by the cubic and quintic
coefficients, and we implement numerical simulations to help us to quantify the
validity of the procedure.Comment: 6 pages, 4 figures; version to appear in PR
Orientation in the diagnosis of intraocular neoplasia, through intraocular fine needle aspiration (IFNA)
IFNA is a safe diagnostic technique that allows diagnostic of neoplastic and inflammatory processes of the eye1. In cats melanoma is common in the eye, skin and oral cavity2. In the eyep, local infiltration to systemic metastases may occur2. Being, the IFNA a method that assists in the diagnosis and therapeutics1,3,4,5. An european female cat, seven years old, was presented to consultation with brown patches of progressive growth in the right iris for four months. The pupillary light reflex, dazzle and menace response were present, and the ocular echography showed an area with iris thickening and with hyperechogenicity1. Due to clinical suspicion of iris melanoma, it was requested radiographic examination of the thorax, abdominal ultrasonography, hematological and biochemical blood analysis1,2, revealing no alterations. The IFNA was performed under general anesthesia introducing the a 26 gauge needle near the limbus and directed to the iris lesion with the bevel facing the surface of the mass3,4. The technique was performed without complications. The cytology using hematoxylin and eosin staining revealed moderate cellularity composed of rounded cells with moderate nuclear pleomorphism, bulky, pale cytoplasm1. The atypical round cells were suggestive of round cell amelanotic melanoma. Due to the cytological orientation, the enucleation of right eye was advised to the owner, which was declined.The diagnosis of ocular melanoma can be directed on clinical grounds and confirmed by anatomopathological exams2. IFNA is a practical, method in aiding the differentiation of neoplastic from non-neoplastic processes. It also helps guiding the surgical procedure and establishing prognosis1,3,4,5
LAMELAR CORNEAL TRANSPLANTATION IN A DOG FOR SURGICAL TREATMENT OF CORNEA DEEP ULCER WITH DESCEMETOCELE.
Corneal transplantation is a procedure indicated for surgical treatment of several corneal diseases, requiring replacement of the affected tissues1,2,3,4. A dog of undefined breed, 5 years old, revealed on ocular examination, a deep corneal ulcer and a Descemet\'s membrane (DM) exposure. Aiming at corneal repair, the surgical technique of lamellar corneal transplantation was used. The perimeter of the transplant was defined with the help of a biopsy punch. With a 1 ml syringe and a 26 G” needle, air was injected into the deep corneal stroma in order to separate DM from stroma1,2. Subsequently paracentesis was performed to reduce ocular pressure and a small air bubble was added in order to help the corneal depthness perspective. With a crescent knife, excision of the compromised tissue was performed1,3. The DM was covered using cryopreserved canine cornea4 at -20°C in 3mg/ml tobramycin solution and thawed at room temperature it was also molded obtaining the appropriate sized tissue for the recoil1. The corneal suture was made using simple isolated points with 8-0 polyglactin and for corneal protection a third eyelid flap was performed1,3. Topical moxifloxacin, tropicamide, EDTA and autologous serum were used in post-surgical treatment3. The third eyelid flap was removed at 15 days post-surgery and a complete corneal repair was observed with total incorporation in the recipient cornea. Lamellar corneal transplantation employing cryopreserved cornea in tobramycin solution has been shown to be effective in the surgical treatment of descemetocele when related to other techniques1,3,4
A proposal to implement a quantum delayed choice experiment assisted by a cavity QED
We propose a scheme feasible with current technology to implement a quantum
delayed-choice experiment in the realm of cavity QED. Our scheme uses two-level
atoms interacting on and off resonantly with a single mode of a high Q cavity.
At the end of the protocol, the state of the cavity returns to its ground
state, allowing new sequential operations. The particle and wave behavior,
which are verified in a single experimental setup, are postselected after the
atomic states are selectively detected.Comment: 3 pages, 3 figures. arXiv admin note: text overlap with
arXiv:1208.0802 by other author
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