Equivalence of Bose-Einstein condensation and symmetry breaking

Based on a classic paper by Ginibre [Commun. Math. Phys. {\bf 8} 26 (1968)] it is shown that whenever Bogoliubov's approximation, that is, the replacement of a_0 and a_0^* by complex numbers in the Hamiltonian, asymptotically yields the right pressure, it also implies the asymptotic equality of ||^2/V and /V in symmetry breaking fields, irrespective of the existence or absence of Bose-Einstein condensation. Because the former was proved by Ginibre to hold for absolutely integrable superstable pair interactions, the latter is equally valid in this case. Apart from Ginibre's work, our proof uses only a simple convexity inequality due to Griffiths.Comment: An error in my summary of previous results (the definition of F') is corrected. The correction is to be done also in the PR

Heat Transport in Mesoscopic Systems

Phonon heat transport in mesoscopic systems is investigated using methods analogous to the Landauer description of electrical conductance. A "universal heat conductance" expression that depends on the properties of the conducting pathway only through the mode cutoff frequencies is derived. Corrections due to reflections at the junction between the thermal body and the conducting bridge are found to be small except at very low temperatures where only the lowest few bridge modes are excited. Various non-equilibrium phonon distributions are studied: a narrow band distribution leads to clear steps in the cooling curve, analogous to the quantized resistance values in narrow wires, but a thermal distribution is too broad to show such features.Comment: To be published in Superlattices and Microstructures, special issue in honor of Rolf Landauer, March 198

Stone in a paracaliceal diverticula managed percutaneously

Introduction: Percutaneous technique of stone removal from a paracaliceal diverticula is presented. Materials and Methods: Paracaliceal diverticula is not a frequent finding. It is associated with narrow communication of the calyx with renal pelvis. Sometime the caliceal communication is angulated which interfere with ESWL management. Until recently, such cases were treated by open surgery. Results: After percutaneously stone removal and repunction in the renal pelvis, a large nephrostomy was maintained for thirty days, transforming the diverticula in a new calyx. After nephrostomy removal, "double J» stent was kept in the urether for two weeks. Conclusions: The percutaneously management of stones in paracaliceal diverticula is accepted as a minimally invasive technique with good results, in hands of an skilled endoscopist

Bilateral staghorn cystinic calculi managed percutaneously

Introduction: The results of percutaneous management of bilateral staghorn cystinic calculi is presented. Materials and Methods: 1 - 4% of all urinary lithiasis is chemically cystinic (1/20.000 population). Usually open surgery is the first choice because of the particulary hardness of this type of stone. The staghorn calculi were removed percutaneously, in series, bilateral. Results: Few small fragments of calculi were abandoned in the right lower calyx and removed several months later. The patient was seen every year for the last three years - no recurrence. Conclusions: Percutanoeus management of cystinic stagorn calculi is shown as an alternative to open surgery

The endoscopic resection in two surgery steps - therapeutic solution in peculiar BPH cases

Objective: The two steps endoscopic resection for BPH can be from the beginning indicated (great adenomas) or imposed during resection (intra-operative or anaesthetic complications or incidents). Material and Methods: Out of 7500 TUR-P done during 1983 - 2000 in our center, from which 57 cases of prostatic adenomas were endoscopic resected in two steps (at maximum of 7 days from the first intervention). This kind of surgical intervention was settled from the beginning in 5 cases (10,6%>), and for the rest it was imposed by the intra-operative complications. Results: The TUR-P intervention in two steps was performed in 5 cases with great adenoma where classical operation was not indicated due to associated organics problems (especially severe respiratory dysfunction, marked obesity, etc), when was respected one lobe and after around one week the operation was ended. For the rest of 52 cases the endoscopic resection had to be stopped because of intra-operative massive bleeding (12 cases), trigonal submination (5 cases), anaesthetical accidents (17 cases) and cardio-vascular balance accidents (18 cases). Conclusions: The endoscopic resection in two steps solved in better conditions patients with prostatic adenomas comparative to an incomplete resection, which would have stressed the symptomatology and complications of those patients

Low-temperature heat transfer in nanowires

The new regime of low-temperature heat transfer in suspended nanowires is predicted. It takes place when (i) only ``acoustic'' phonon modes of the wire are thermally populated and (ii) phonons are subject to the effective elastic scattering. Qualitatively, the main peculiarities of heat transfer originate due to appearance of the flexural modes with high density of states in the wire phonon spectrum. They give rise to the $T^{1/2}$ temperature dependence of the wire thermal conductance. The experimental situations where the new regime is likely to be detected are discussed.Comment: RevTex file, 1 PS figur

Effect of phonon scattering by surface roughness on the universal thermal conductance

The effect of phonon scattering by surface roughness on the thermal conductance in mesoscopic systems at low temperatures is calculated using full elasticity theory. The low frequency behavior of the scattering shows novel power law dependences arising from the unusual properties of the elastic modes. This leads to new predictions for the low temperature depression of the thermal conductance below the ideal universal value. Comparison with the data of Schwab et al. [Nature 404, 974 (2000)] suggests that surface roughness on a scale of the width of the thermal pathway is important in the experiment.Comment: 6 pages, 3 figure