Nonabelian solutions in N=4, D=5 gauged supergravity

We consider static, nonabelian solutions in N=4, D=5 Romans' gauged supergravity model. Numerical arguments are presented for the existence of asymptotically anti-de Sitter configurations in the $N=4^+$ version of the theory, with a dilaton potential presenting a stationary point. Considering the version of the theory with a Liouville dilaton potential, we look for configurations with unusual topology. A new exact solution is presented, and a counterterm method is proposed to compute the mass and action.Comment: 15 pages, 4 figure

Laparoscopic resection of nonparasitar splenic cyst

Government Hospital IMSP SR ACSR, Department of Endoscopy and Miniinvasive Surgery, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introduction: Nonparasitic splenic cysts are rarely disease, and may be congenital or post-traumatic in origin. Traditional management includes total or partial splenectomy, partial cystectomy with marsupialization, percutaneous drainage, and sclerotherapy. A laparoscopic technique used to minimize the risk of splenic loss and cyst recurrence is presented.In the current study, we aimed to evaluate the laparoscopic management of patients with nonparasitic splenic cysts together with their long term follow up progresses.Methods: The cases of 5 patients who underwent surgery for spleen cysts at our hospital over the last 12 years from 1998 to 2010 were analyzed. There are 1 male and 4 female. The mean age was 31 (25 - 36). Symptoms included left upper quadrant pain and there was no history of trauma. Diagnosis was based on ultrasonography (US), and computed tomography (CT) findings. The mean size of cysts was 12 (8 – 15) cm. All patients were managed with laparoscopic partial cystectomy using the diathermic monopolar cutting of the cyst wall and hemostasis by coagulation.Results: All patients had an noncomplicated postoperative course and were discharged home within 3 – 5 days. Operative time was 35 – 90 min., and blood loss was minimal. Pathology finding was a epithelial (mesothelial) cysts. One case (the second of) the operation was finished by laparoscopic splenectomy immediately after resection of the cyst. Decision for splenectomy was caused to marginal bleeding and insufficiency of experience in this kind of procedure. Consecutive follow up in 10 years showed the hyperplasia (6 cm. in diameter) of accessory spleen (initial 1cm. in diameter) in this patient. One patient underwent laparoscopic procedure repeat in two years, but in 3th procedure the spleen was removed because recurrence and infecting of the cyst. Conclusion: 1.Laparoscopic splenic cystectomy can be performed safely. 2.This technique preserves the spleen and minimizes the risk of recurrence of the cyst

Bose-Einstein Condensation of Magnons in Cs2CuCl4

We report on results of specific heat measurements on single crystals of the frustrated quasi-2D spin-1/2 antiferromagnet Cs_2CuCl_4 (T_N=0.595 K) in external magnetic fields B30 mK. Decreasing B from high fields leads to the closure of the field-induced gap in the magnon spectrum at a critical field B_c = 8.51 T and a magnetic phase transition is clearly seen below B_c. In the vicinity to B_c, the phase transition boundary is well described by the power-law T_c(B)\propto (B_c-B)^{1/\phi} with the measured critical exponent \phi\simeq 1.5. These findings are interpreted as a Bose-Einstein condensation of magnons.Comment: 5 pages, 4 figures, experiment and theor

Geometry of General Hypersurfaces in Spacetime: Junction Conditions

We study imbedded hypersurfaces in spacetime whose causal character is allowed to change from point to point. Inherited geometrical structures on these hypersurfaces are defined by two methods: first, the standard rigged connection induced by a rigging vector (a vector not tangent to the hypersurface anywhere); and a second, more physically adapted, where each observer in spacetime induces a new type of connection that we call the rigged metric connection. The generalisation of the Gauss and Codazzi equations are also given. With the above machinery, we attack the problem of matching two spacetimes across a general hypersurface. It is seen that the preliminary junction conditions allowing for the correct definition of Einstein's equations in the distributional sense reduce to the requirement that the first fundamental form of the hypersurface be continuous. The Bianchi identities are then proven to hold in the distributional sense. Next, we find the proper junction conditions which forbid the appearance of singular parts in the curvature. Finally, we derive the physical implications of the junction conditions: only six independent discontinuities of the Riemann tensor are allowed. These are six matter discontinuities at non-null points of the hypersurface. For null points, the existence of two arbitrary discontinuities of the Weyl tensor (together with four in the matter tensor) are also allowed.Comment: Latex, no figure

Memory Effect and Triplet Pairing Generation in the Superconducting Exchange Biased Co/CoOx/Cu41Ni59/Nb/Cu41Ni59 Layered Heterostructure

We fabricated a nanolayered hybrid superconductor-ferromagnet spin-valve structure, the resistive state of which depends on the preceding magnetic field polarity. The effect is based on a strong exchange bias (about -2 kOe) on a diluted ferromagnetic copper-nickel alloy and generation of a long range odd in frequency triplet pairing component. The difference of high and low resistance states at zero magnetic field is 90% of the normal state resistance for a transport current of 250 {\mu}A and still around 42% for 10 {\mu}A. Both logic states of the structure do not require biasing fields or currents in the idle mode.Comment: 9 pages, 4 figures, Accepted to Applied Physics Letter

Exchange bias and interface electronic structure in Ni/Co3O4(011)

A detailed study of the exchange bias effect and the interfacial electronic structure in Ni/Co3O4(011) is reported. Large exchange anisotropies are observed at low temperatures, and the exchange bias effect persists to temperatures well above the Neel temperature of bulk Co3O4, of about 40 K: to ~80 K for Ni films deposited on well ordered oxide surfaces, and ~150 K for Ni films deposited on rougher Co3O4 surfaces. Photoelectron spectroscopy measurements as a function of Ni thickness show that Co reduction and Ni oxidation occur over an extended interfacial region. We conclude that the exchange bias observed in Ni/Co3O4, and in similar ferromagnetic metallic/Co3O4 systems, is not intrinsic to Co3O4 but rather due to the formation of CoO at the interface.Comment: 8 pages, 6 figures. Accepted for publication in Physical Review B

Incisional hernias – results of present therapy options

Sp. Sf. Pantelimon, București, Al XI-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova și cea de-a XXXIII-a Reuniune a Chirurgilor din Moldova „Iacomi-Răzeșu” 27-30 septembrie 2011Introducere: Hernia incizională este cea mai frecventă complicație după operațiile abdominale. Este dificil de estimat exact costul acestei patologii pentru societate. Dacă adăugam la costul intervenției chirurgicale și costul spitalizării, dificultățile operațiilor de recidivă multiplă, costul protezelor, morbiditățile pacienților neoperați, afectarea capacității de muncă și a calității vieții, vom avea magnitudinea problemei dezvoltate de această complicație redutabilă a tuturor intervențiilor chirurgicale. Material și metodă: Am analizat rezultatele mai multor studii de prestigiu ale unor colective românești și internaționale în domeniul herniilor incizionale. Rezultate: Din nefericire rezultatele globale ale tratamentului în hernia incizională oscilează între 12-63% pentru procedeele tisulare și între 2-36% pentru procedeele allopalstice. Abordul chirurgical este cel mai adesea bazat pe traditie si pe liberul arbitru, decat pe evidențe statistice sau ghiduri de tratament. Nu este deloc surprinzător faptul că, în ciuda noilor cuceriri în domeniul defectelor parietale și a folosirii explozive a protezelor, rata de re-operații pentru recidiva incizională se situează la același nivel. Concluzii: Componența operatorie ca unică etiologie în hernia incizională este supraestimată. Datorită faptului că și alți factori etiologici, cunoscuți sau nu, concura la apariția herniei incizionale și la re-recidivă, și datorită faptului că acești “factori” nu sunt deocamdată influențabili de tratamentul medical nu ne rămțne decât să analizăm lucid și responsabil factorii chirurg-dependenți. Greselile de tactică/tehnică chirurgicală trebuie evidențiate, explicate, și înlăturate. Soluția nu este o abordare pur tehnică, ci una fiziologică, în termeni de elasticitate, complianța și rezistența a întregului perete abdominal, deseori modificat profund de marile defecte incizionale.Introduction: incisional hernia is the most common complication after abdominal surgery. It is difficult to estimate the exact cost to society of this pathology. If we add to the cost of surgery and hospitalization costs, the difficulties of relapse multiple operations, the cost of prostheses, unoperated patient morbidity, impaired work capacity and quality of life, the magnitude of the problem we have developed this redoubtable complication of all surgical procedures. Methods: We analyzed the results of several studies of prestigious romanian and international collectives about incisional hernias. Results: Unfortunately, the overall results of treatment in incisional hernia procedures vary between 12-63% for tissular procedures and between 2-36% for allopalstic procedures. Surgical approach is most often based on tradition and the free will, rather than obvious statistical treatment guidelines. Not surprisingly, despite the new advancements in the field of herniology and the use of new parietal prosthesis, the rate of re-operations for recurrent incisional fall at the same level. Conclusions: Surgery as the only component in etiology of incisional hernias is overestimated. Due to the fact that other etiological factors, known or not compete in the emergence and re-incision hernia recurrence, and because these “factors” are not influenced by medical treatment for now, we are just lucid and analyze the factors responsible - surgeon dependent. Mistakes tactics/surgical technique must be highlighted, explained and removed. The solution is not a purely technical approach, but a physiological, in terms of elasticity, compliance and resistance of the entire abdominal wall

Quantum effects in a rotating spacetime

The behavior of a arbitrary coupled quantum scalar field is studied in the background of the G\"odel spacetime. Closed forms are derived for the effective action and the vacuum expectation value of quadratic field fluctuations by using $\zeta$-function regularization. Based on these results, we argue that causality violation presented in this spacetime can not be removed by quantum effects.Comment: 17 pages, LaTe

Shell Structures and Chaos in Deformed Nuclei and Large Metallic Clusters

A reflection-asymmetric deformed oscillator potential is analysed from the classical and quantum mechanical point of view. The connection between occurrence of shell structures and classical periodic orbits is studied using the ''removal of resonances method'' in a classical analysis. In this approximation, the effective single particle potential becomes separable and the frequencies of the classical trajectories are easily determined. It turns out that the winding numbers calculated in this way are in good agreement with the ones found from the corresponding quantum mechanical spectrum using the particle number dependence of the fluctuating part of the total energy. When the octupole term is switched on it is found that prolate shapes are stable against chaos whereas spherical and oblate cases become chaotic. An attempt is made to explain this difference in the quantum mechanical context by looking at the distribution of exceptional points which results from the matrix structure of the respective Hamiltonians. In a similar way we analyse the modified Nilsson model and discuss its consequences for nuclei and metallic clusters.Comment: to appear in Physica Scripta., CNLS-94-02, a talk given at the Nobel sponsored conference SELMA 94 "New Nuclear Phenomena in the Vicinity of Closed Shell" (Stockholm and Uppsala, 29 Aug.- 3 Sept. 1994

Adiabatic non-equilibrium steady states in the partition free approach

Consider a small sample coupled to a finite number of leads, and assume that the total (continuous) system is at thermal equilibrium in the remote past. We construct a non-equilibrium steady state (NESS) by adiabatically turning on an electrical bias between the leads. The main mathematical challenge is to show that certain adiabatic wave operators exist, and to identify their strong limit when the adiabatic parameter tends to zero. Our NESS is different from, though closely related with the NESS provided by the Jak{\v s}i{\'c}-Pillet-Ruelle approach. Thus we partly settle a question asked by Caroli {\it et al} in 1971 regarding the (non)equivalence between the partitioned and partition-free approaches