Optimal antibunching in passive photonic devices based on coupled nonlinear resonators

We propose the use of weakly nonlinear passive materials for prospective applications in integrated quantum photonics. It is shown that strong enhancement of native optical nonlinearities by electromagnetic field confinement in photonic crystal resonators can lead to single-photon generation only exploiting the quantum interference of two coupled modes and the effect of photon blockade under resonant coherent driving. For realistic system parameters in state of the art microcavities, the efficiency of such single-photon source is theoretically characterized by means of the second-order correlation function at zero time delay as the main figure of merit, where major sources of loss and decoherence are taken into account within a standard master equation treatment. These results could stimulate the realization of integrated quantum photonic devices based on non-resonant material media, fully integrable with current semiconductor technology and matching the relevant telecom band operational wavelengths, as an alternative to single-photon nonlinear devices based on cavity-QED with artificial atoms or single atomic-like emitters.Comment: to appear in New J. Physic

D-brane probes on G2 Orbifolds

We consider type IIB string theory on a seven dimensional orbifold with holonomy in G2. The motivation is to use D1-branes as probes of the geometry. The low energy theory on the D1-brane is a sigma-model with two real supercharges (N = (1,1) in two dimensional language). We study in detail the closed and open string sectors and propose a coupling of the twisted fields to the brane that modifies the vacuum moduli space so that the singularity at the origin is removed. Instead of coming from D-terms, which are not present here, the modification comes from a ``twisted'' mass term for the seven scalar multiplets on the brane. The proposed mechanism involves a generalization of the moment map.Comment: 16 pages; v2: References added; v3: Erroneous interpretation of twisted moduli corrected, acknowledgments adde

A Novel Ultrasound-based Measure of the Liver among Diabetes Mellitus Type II Patients

Diabetes mellitus type II (DM II) or adult onset diabetes is due to the inefficient use of insulin, which affects various organs and tissues. Patients with DM II are at risk of suffering non-alcoholic fatty liver disease (NAFLD) that can later develop into more life threating forms such as hepatomegaly, cirrhosis or liver cancer. Following the logic of the non-inferiority trial test, we aim to establish a more accurate anatomical measure of the right liver lobe (RLL) to facilitate close monitoring of liver size with ultrasound (US). We hypothesize that US is not unacceptably worse than computed tomography (CT) or magnetic resonance imaging (MRI) to accurately and reliably measure the size of the RLL when the measure is taken in the midaxillary line and craniocaudal plane (MAL-CC). Therefore, the objective of this study is to conduct a non-inferiority trial to test our novel MAL-CC measure. To meet this aim, US measure of the RLL was taken from DM II (n=7) and non-DM II (n=5) patients, whom were recruited from 2 endocrinology clinics at SoM-UPR. Preliminary data shows that MAL-CC measure of the RLL from non-DM II patients is 13.99 + 2.53 cm whereas the same measurement among DM II patients is 15.25 + 3.25 cm (Mann-Whitney U test, p= 0.42). It is concluded that there is a non-significant trend for large RLL sizes among DM II patients. Future work aims to increase sample size and to validate our novel measurement with MRI

Tree level spontaneous R-symmetry breaking in O'Raifeartaigh models

We show that in O'Raifeartaigh models of spontaneous supersymmetry breaking, R-symmetries can be broken by non-zero values of fields at tree level, rather than by vacuum expectation values of pseudomoduli at loop level. As a complement of the recent result by Shih, we show that there must be a field in the theory with R-charge different from zero and two in order for R-symmetry breaking to occur, no matter whether the breaking happens at tree or loop level. We review the example by CDFM, and construct two types of tree level R-symmetry breaking models with a wide range of parameters and free of runaway problem. And the R-symmetry is broken everywhere on the pseudomoduli space in these models. This provides a rich set of candidates for SUSY model building and phenomenology.Comment: 8 pages; v2: major revision to section 6; v3: minor revision and typos; v4: typos, published version; v5: fix Latex syntax error, published versio

The effect of density on the delicate balance between structural requirements and environmental issues for AAC blocks: An experimental investigation

Among other construction materials, Autoclaved Aerated Concrete (AAC) offers several advantages to face the pressing need to build more sustainable and energy-efficient buildings. From the building side, the low thermal conductivity of AAC allows the realization of energy-efficient building envelopes, with interesting savings in terms of heating and cooling processes. The equilibrium between structural performances (related to safety issues) and energy efficiency requirements is, however, very delicate since it is strictly related to the search for an “optimum” material density. Within this context, this work discusses the results of wide experimental research, showing the dependency of the most important mechanical properties (compressive strength, elastic modulus, flexural strength and fracture energy) from density, as well as the corresponding variation in thermal conductivity. In order to identify the better compromise solution, a sort of eco-mechanical index is also defined. The big challenge for future researches will be the improvement of this eco-mechanical index by working on pore structure and pore distribution within the material without significantly reducing the density and/or by improving the strength of the skeleton material

Impressive long-term response with pertuzumab and trastuzumab in HER2-positive breast cancer with brain metastasis

This is a case report of a 40-year-old woman who, after conservative breast cancer treatment, developed a HER2 positive solitary brain metastasis in the left temporal lobe, without extracranial disease. She underwent surgery resection followed by stereotactic radiotherapy and, because of early brain progression, she was submitted to the first line therapy with pertuzumab, trastuzumab and weekly paclitaxel. After six months of treatment, a brain magnetic resonance imaging revealed a complete disappearance of brain recurrence, which persisted for more than 24 months

Notes on SUSY and R-Symmetry Breaking in Wess-Zumino Models

We study aspects of Wess-Zumino models related to SUSY and R-symmetry breaking at tree-level. We present a recipe for constructing a wide class of tree-level SUSY and R-breaking models. We also deduce a general property shared by all tree-level SUSY breaking models that has broad application to model building. In particular, it explains why many models of direct gauge mediation have anomalously light gauginos (even if the R-symmetry is broken spontaneously by an order one amount). This suggests new approaches to dynamical SUSY breaking which can generate large enough gaugino masses.Comment: 23 pages. v2: references added, minor changes. v3: comment on non-renormalizable case adde

Evidence for pseudogap and phase-coherence gap separation by Andreev reflection experiments in Au/La_{2-x}Sr_{x}CuO_4 point-contact junctions

We present new Au/La_{2-x}Sr_{x}CuO_{4} (LSCO) point-contact conductance measures as a function of voltage and temperature in samples with 0.08 <= x <= 0.2. Andreev reflection features disappear at about the bulk Tc, giving no evidence of gap for T > Tc. The fit of the normalized conductance at any T < Tc supports a (s + d)-wave symmetry of the gap, whose dominant low-T s component follows the Tc(x) curve in contrast with recent angle-resolved photoemission spectroscopy and quasiparticle tunneling data. These results prove the separation between pseudogap and phase-coherence superconducting gap in LSCO at x <= 0.2.Comment: 4 pages, 4 eps figures, 1 table (RevTeX). Labels added to Fig. 1; Fig. 3 resized; references added; short discussion about ballistic contact regime adde

Considering the Cellular Composition of Olfactory Ensheathing Cell Transplants for Spinal Cord Injury Repair: A Review of the Literature

Olfactory ensheathing cells (OECs) are specialized glia cells of the olfactory system that support the continual regeneration of olfactory neurons throughout adulthood. Owing to their pro-regenerative properties, OECs have been transplanted in animal models of spinal cord injuries (SCI) and trialed in clinical studies on SCI patients. Although these studies have provided convincing evidence to support the continued development of OEC transplantation as a treatment option for the repair of SCI, discrepancies in the reported outcome has shown that OEC transplantation requires further improvement. Much of the variability in the reparative potential of OEC transplants is due to the variations in the cell composition of transplants between studies. As a result, the optimal cell preparation is currently a subject of debate. Here we review, the characterization as well as the effect of the cell composition of olfactory cell transplantation on therapeutic outcome in SCI. Firstly, we summarize and review the cell composition of olfactory cell preparations across the different species studied prior to transplantation. Since the purity of cells in olfactory transplants might affect the study outcome we also examine the effect of the proportions of OECs and the different cell types identified in the transplant on neuroregeneration. Finally, we consider the effect of the yield of cells on neuroregeneration by assessing the cell dose of transplants on therapeutic outcome

A Continuum Approach to the Nonlinear In-Plane Galloping of Shallow Flexible Cables

The aeroelastic stability of horizontal, suspended, shallow, iced cables is studied via a continuum model. Both external and internal damping, consistent with the Rayleigh model, are taken into account. The quasi-static theory of the aerodynamic forces is applied. An in-plane nonlinear model of galloping is formulated, displaying the importance of internal damping, both on the critical velocity and on the limit-cycle amplitude. A perturbation procedure is developed for nonlinear analysis in nonresonant conditions (monomodal galloping). The modification of the galloping mode due to quadratic nonlinearities is studied, and its real or complex character is discussed