Resonant X-Ray Scattering Measurements of a Spatial Modulation of the Cu 3d and O 2p Energies in Stripe-Ordered Cuprate Superconductors

A prevailing description of the stripe phase in underdoped cuprate superconductors is that the charge carriers (holes) phase segregate on a microscopic scale into hole rich and hole poor regions. We report resonant elastic x-ray scattering measurements of stripe-ordered La$_{1.475}$Nd$_{0.4}$Sr$_{0.125}$CuO$_4$ at the Cu $L$ and O $K$ absorption edges that identify an additional feature of stripe order. Analysis of the energy dependence of the scattering intensity reveals that the dominant signature of the stripe order is a spatial modulation in the energies of Cu 3d and O 2p states rather than the large modulation of the charge density (valence) envisioned in the common stripe paradigm. These energy shifts are interpreted as a spatial modulation of the electronic structure and may point to a valence-bond-solid interpretation of the stripe phase.Comment: 5 pages, 2 figure

Flow patterns and heat transfer in a square cross-section micro condenser working at low mass fluxes

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Flow patterns and heat transfer in an air-cooled square cross-section micro condenser were investigated. The test section consisted of a borosilicate square micro channel, of inner and outer hydraulic diameters of 0.49 mm and 0.6 mm respectively, and a length of 100 mm. The transparent material of the micro channel allowed the visualization of the different condensation flow patterns. The imposed mass velocities were ranging between 1 and 10 kg m-2 s-1. In this range of mass fluxes, three main flow regimes were identified: Annular regime, intermittent regime, and spherical bubbles regime. Then, the isolated bubbles zone (the end of the intermittent zone + the spherical bubbles zone) was particularly studied. A specific experimental procedure was developed, basing on bubble tracking, in order to determine accurately the hydraulic and thermal parameters profiles in this zone according to the axial position in the micro channel, such as the vapour quality profile x(z). Thanks to energy balance, the liquid temperature profile Tl(z) in the isolated bubbles zone was determined for different initial values. A thermal non-equilibrium between the liquid and vapour phases was identified. Therefore, the latent heat flux was then quantified and compared to the total heat flux in this zone.FNRAE (MATRAS) and the Microgravity Application Program of the European Space Agenc

Automated condition monitoring of mill ball size distribution and grate open area

Grinding media in coarse grinding tumbling mills constitute the biggest consumable cost to a comminution processing plant, therefore it is critically important to minimize associated wear. Secondly, efficient grinding is dependent on tight control of the desired ball size distribution, or else optimum impact breakage cannot be assured. Despite the significance of minitoring ball size distribution for mill operation, no practically deployable systems are currently in industry use to measure it. This paper describes a new method for highly accurate, comprehensive, and rapid determination of ball size distribution.Accurate SAG and AG mill product size control is dependent on appropriate Grate Open Area dimensions. Wear of the grate hole edges or in the plate thickness results in an increase of the open area due to the tapered hole cross section, which can result in oversize product exiting the mill. Conversely, some grate castings feature peening of the edges during mill operation, thereby decreasing open area, and therefore preventing the desireed top size product from exiting the mill.SAG mill throughput requires grate holes to remain open or else throughput is restricted. Many grates in operation are pegged by grinding media to varying degrees of severity. This paper introduces a comprehensive, accurate and rapid method to measure and track the size and pegging status of each and all grate holes in situ, and therefore provides tracking information on the Open Area of a SAG mill. This enables operators to control the primary mill product size and therefore the opportunity to stabilize downstream processes

Monitoring the Paraguayan epidemiological dengue surveillance system (2009-2011) using Benford's law

Introduction: Dengue is the most widespread arbovirus worldwide. In Paraguay, it reappeared in 1988-1989, with one of the largest epidemic outbreaks occurring in 2011. Objective: To evaluate the performance of the dengue epidemiological surveillance system in Paraguay between 2009 and 2011. Materials and methods: We conducted an ecological study with secondary epidemiological surveillance data. We analyzed notified cases of the disease based on the distribution expected by Benford's law. To this end, we used the first and second digits from the global records stratified by region, season, population density, indicators of housing conditions and heads of cattle. Results: The epidemiological surveillance system performed better during non-epidemic periods and in the states with better housing conditions and fewer heads of cattle. Conclusion: Given that a difference in the performance existed, we recommended that the system remains operating at the same high alert level even during periods when fewer cases are expected. The technology used by the method proposed to monitor the notification of cases is easy to transfer to operational staff

Bortezomib in Kidney Transplantation

Although current therapies for pretransplant desensitization and treatment of antibody-mediated rejection (AMR) have had some success, they do not specifically deplete plasma cells that produce antihuman leukocyte antigen (HLA) antibodies. Bortezomib, a proteasome inhibitor approved for the treatment of multiple myeloma (a plasma cell neoplasm), induces plasma cell apoptosis. In this paper we review the current body of literature regarding the use of this biological agent in the field of transplantation. Although limited experience with bortezomib may seem to show promise in the realm of transplant recipients desensitization and treatment of AMR, there is also experience that may suggest otherwise. Bortezomib's role in desensitization protocols and treatment of AMR will be defined better as more clinical data and trials become available

The symmetry of charge order in cuprates

Charge-ordered ground states permeate the phenomenology of 3d-based transition metal oxides, and more generally represent a distinctive hallmark of strongly-correlated states of matter. The recent discovery of charge order in various cuprate families fueled new interest into the role played by this incipient broken symmetry within the complex phase diagram of high-Tc superconductors. Here we use resonant X-ray scattering to resolve the main characteristics of the charge-modulated state in two cuprate families: Bi2201 and YBCO. We detect no signatures of spatial modulations along the nodal direction in Bi2201, thus clarifying the inter-unit-cell momentum-structure of charge order. We also resolve the intra-unit-cell symmetry of the charge ordered state, which is revealed to be best represented by a bond-order with modulated charges on the O-2p orbitals and a prominent d-wave character. These results provide insights on the microscopic description of charge order in cuprates, and on its origin and interplay with superconductivity.Comment: A high-resolution version with supplementary material can be found at: http://www.phas.ubc.ca/~quantmat/ARPES/PUBLICATIONS/Articles/CDW_symmetry.pd