Dirac Quantization of Open Strings and Noncommutativity in Branes

We apply the Dirac bracket quantization to open strings attached to branes in the presence of background antisymmetric field and recover an inherent noncommutativity in the internal coordinates of the brane.Comment: 25 pp, typos corrected, minor change

Complete factorization of equations of motion in Wess-Zumino theory

We prove that the equations of motion describing domain walls in a Wess-Zumino theory involving only one chiral matter multiplet can be factorized into first order Bogomol'nyi equations, so that all the topological defects are of the Bogomol'nyi-Prasad-Sommerfield type.Comment: Revtex, 3 pages. Written after hep-th/0103041, to appear in PL

Complete factorization of equations of motion in supersymmetric field theories

We investigate bosonic sectors of supersymmetric field theories. We consider superpotentials described by one and by two real scalar fields, and we show how the equations of motion can be factorized into a family of first order Bogomol'nyi equations, so that all the topological defects are of the Bogomol'nyi-Prasad-Sommerfield type. We examine explicit models, that engender the Z_N symmetry, and we identify all the topological sectors, illustrating their integrability.Comment: Revtex, 6 pages; version to be published in Nucl. Phys.

Field-induced segregation of ferromagnetic nano-domains in Pr0.5_{0.5}Sr0.5_{0.5}MnO3_3, detected by 55^{55}Mn NMR

The antiferromagnetic manganite Pr$_{0.5}$Sr$_{0.5}$MnO$_3$ was investigated at low temperature by means of magnetometry and $^{55}$Mn NMR. A field-induced transition to a ferromagnetic state is detected by magnetization measurements at a threshold field of a few tesla. NMR shows that the ferromagnetic phase develops from zero field by the nucleation of microscopic ferromagnetic domains, consisting of an inhomogeneous mixture of tilted and fully aligned parts. At the threshold the NMR spectrum changes discontinuously into that of a homogeneous, fully aligned, ferromagnetic state, suggesting a percolative origin for the ferromagnetic transition.Comment: Latex 2.09 language. 4 pages, 3 figures, 23 references. Submitted to physical Review

Educational effects using a robot patient simulation system for development of clinical attitude

Introduction: The aim of this study was to assess the effectiveness of improving the attitude of dental students toward the use of a full-body patient simulation system (SIMROID) compared to the traditional mannequin (CLINSIM) for dental clinical education. Materials and methods: The participants were 10 male undergraduate dental students who had finished clinical training in the university hospital 1 year before this study started. They performed a crown preparation on an upper premolar tooth using SIMROID and CLINSIM as the practical clinical trials. The elapsed time for preparation was recorded. The taper of the abutment teeth was measured using a 3-dimensional shape-measuring device after this trial. In addition, a self-reported questionnaire was collected that included physical pain, treatment safety, and maintaining a clean area for each simulator. Qualitative data analysis of a free format report about SIMROID was performed using text-mining analysis. This trial was performed twice at 1-month intervals. Results: The students considered physical pain, treatment safety, and a clean area for SIMROID significantly better than that for CLINSIM (P < 0.01). The elapsed time of preparation in the second practical clinical trial was significantly lower than in the first for SIMROID and CLINSIM (P < 0.01). However, there were no significant differences between the abutment tapers for both systems. For the text-mining analysis, most of the students wrote that SIMROID was similar to real patients. Conclusion: The use of SIMROID was proven to be effective in improving the attitude of students toward patients, thereby giving importance to considerations for actual patients during dental treatment

Strong Coupling Effects in non-commutative spaces from OM Theory and supergravity

We show that a four-parameter class of 3+1 dimensional NCOS theories can be obtained by dimensional reduction on a general 2-torus from OM theory. Compactifying two spatial directions of NCOS theory on a 2-torus, we study the transformation properties under the $SO(2,2;Z)$ T-duality group. We then discuss non-perturbative configurations of non-commutative super Yang-Mills theory. In particular, we calculate the tension for magnetic monopoles and (p,q) dyons and exhibit their six-dimensional origin, and construct a supergravity solution representing an instanton in the gauge theory. We also compute the potential for a monopole-antimonopole in the supergravity approximation.Comment: 24 pages, latex. Explanations adde