Valence-bond theory of highly disordered quantum antiferromagnets

We present a large-N variational approach to describe the magnetism of insulating doped semiconductors based on a disorder-generalization of the resonating-valence-bond theory for quantum antiferromagnets. This method captures all the qualitative and even quantitative predictions of the strong-disorder renormalization group approach over the entire experimentally relevant temperature range. Finally, by mapping the problem on a hard-sphere fluid, we could provide an essentially exact analytic solution without any adjustable parameters.Comment: 5 pages, 3 eps figure

Patient-specific 3D Printed Liver Models for Pre-operative Planning and Improved Patient Adherence

Project Background: 3D anatomical relationships in the liver are not always visually accessible for surgeons performing resections even with advanced imaging options. Firm understanding of these relationships is essential for timely procedures, which can improve patient outcomes and lower hospital expenses. Patient-specific 3D modeling has existed for some time, though it is costly. New cost-effective techniques have surfaced which may yield opportunities for more effective preoperative planning in liver surgery and improved patient adherence. Methods: Digital patient-specific 3D reconstruction of a liver was completed by interpolating data from MRI scans using 3D Slicer, a segmenting program. The liver model was processed and 3D printed as a shell to be used as a mold. The liver shell, associated vasculature, and tumor were printed using polylactic acid (PLA) filament on an Ultimaker S5 3D printer. Transparent silicone was used as a cast, giving the model a solid form yet still allowing examination of the inside contents. Results: One completed liver model was used in pre-surgical consultation of a patient with hepatocellular carcinoma undergoing liver resection and during the surgical procedure as a guide for the surgical team. A follow-up survey concerning qualitative aspects of the model administered to the surgical team suggested high accuracy of the model compared to the anatomy observed during the procedure. Conclusion: Cost-effective techniques in producing patient specific 3D anatomical models appears not only feasible, but highly effective in improving communication between the surgical team during the procedure and also between the surgeon and the patient during pre-surgical consultation. Future research may be conducted concerning the model’s visual clarity as well as impact on patient adherence post-op

Constraining nonstandard neutrino-quark interactions with solar, reactor and accelerator data

We present a reanalysis of nonstandard neutrino-down-quark interactions of electron and tau neutrinos using solar, reactor and accelerator data. In addition updating the analysis by including new solar data from SNO phase III and Borexino, as well as new KamLAND data and solar fluxes, a key role is played in our analysis by the combination of these results with the CHARM data. The latter allows us to better constrain the axial and axial-vector electron and tau-neutrino nonstandard interaction parameters characterizing the deviations from the Standard Model predictions.Comment: 11 pages, 6 figures, 2 tables, typo corrected in Figure 2, version published in Phys. Rev.

Electrical characterization of the soft breakdown failure mode in MgO layers

The soft breakdown (SBD) failure mode in 20 nm thick MgO dielectric layers grown on Si substrates was investigated. We show that during a constant voltage stress, charge trapping and progressive breakdown coexist, and that the degradation dynamics is captured by a power-law time dependence. We also show that the SBD current-voltage (I-V) characteristics follow the power-law model I = aVb typical of this conduction mechanism but in a wider voltage window than the one reported in the past for SiO2. The relationship between the magnitude of the current and the normalized differential conductance was analyzed