A Comparison of Blocking Methods for Record Linkage

Record linkage seeks to merge databases and to remove duplicates when unique identifiers are not available. Most approaches use blocking techniques to reduce the computational complexity associated with record linkage. We review traditional blocking techniques, which typically partition the records according to a set of field attributes, and consider two variants of a method known as locality sensitive hashing, sometimes referred to as "private blocking." We compare these approaches in terms of their recall, reduction ratio, and computational complexity. We evaluate these methods using different synthetic datafiles and conclude with a discussion of privacy-related issues.Comment: 22 pages, 2 tables, 7 figure

Allosteric control of cyclic di-GMP signaling

Cyclic di-guanosine monophosphate is a bacterial second messenger that has been implicated in biofilm formation, antibiotic resistance, and persistence of pathogenic bacteria in their animal host. Although the enzymes responsible for the regulation of cellular levels of c-di-GMP, diguanylate cyclases (DGC) and phosphodiesterases, have been identified recently, little information is available on the molecular mechanisms involved in controlling the activity of these key enzymes or on the specific interactions of c-di-GMP with effector proteins. By using a combination of genetic, biochemical, and modeling techniques we demonstrate that an allosteric binding site for c-di-GMP (I-site) is responsible for non-competitive product inhibition of DGCs. The I-site was mapped in both multi- and single domain DGC proteins and is fully contained within the GGDEF domain itself. In vivo selection experiments and kinetic analysis of the evolved I-site mutants led to the definition of an RXXD motif as the core c-di-GMP binding site. Based on these results and based on the observation that the I-site is conserved in a majority of known and potential DGC proteins, we propose that product inhibition of DGCs is of fundamental importance for c-di-GMP signaling and cellular homeostasis. The definition of the I-site binding pocket provides an entry point into unraveling the molecular mechanisms of ligand-protein interactions involved in c-di-GMP signaling and makes DGCs a valuable target for drug design to develop new strategies against biofilm-related diseases

Different methods of evaluation of Monilinia laxa on apricot flowers and branches

- Organic apricot production is currently not profitable. - The main obstacle to sustainable profitability is brown rot caused by the fungus Monilinia laxa (Aderh. & Ruhl). - In the current apricot germplasm no source of total resistance has been shown, but some varieties are expressing interesting levels of tolerance. - A good evaluation of the M. laxa symptoms is essential for a precise diagnosis of the infection and to appreciate differences between tolerant and susceptible varieties and genotypes

Infrared anomalous Hall effect in SrRuO3_3: Evidence for crossover to intrinsic behavior

The origin of the Hall effect in many itinerant ferromagnets is still not resolved, with an anomalous contribution from the sample magnetization that can exhibit extrinsic or intrinsic behavior. We report the first mid-infared (MIR) measurements of the complex Hall ($\theta_H$), Faraday ($\theta_F$), and Kerr ($\theta_K$) angles, as well as the Hall conductivity ($\sigma_{xy}$) in a SrRuO$_3$ film in the 115-1400 meV energy range. The magnetic field, temperature, and frequency dependence of the Hall effect is explored. The MIR magneto-optical response shows very strong frequency dependence, including sign changes. Below 200 meV, the MIR $\theta_H (T)$ changes sign between 120 and 150 K, as is observed in dc Hall measurements. Above 200 meV, the temperature dependence of $\theta_H$ is similar to that of the dc magnetization and the measurements are in good agreement with predictions from a band calculation for the intrinsic anomalous Hall effect (AHE). The temperature and frequency dependence of the measured Hall effect suggests that whereas the behavior above 200 meV is consistent with an intrinsic AHE, the extrinsic AHE plays an important role in the lower energy response.Comment: The resolution of figures is improve

Spectroscopic imaging of single atoms within a bulk solid

The ability to localize, identify and measure the electronic environment of individual atoms will provide fundamental insights into many issues in materials science, physics and nanotechnology. We demonstrate, using an aberration-corrected scanning transmission microscope, the spectroscopic imaging of single La atoms inside CaTiO3. Dynamical simulations confirm that the spectroscopic information is spatially confined around the scattering atom. Furthermore we show how the depth of the atom within the crystal may be estimated.Comment: 4 pages and 3 figures. Accepted in Phys.Rev.Let

Electrochemical capacitance of a leaky nano-capacitor

We report a detailed theoretical investigation on electrochemical capacitance of a nanoscale capacitor where there is a DC coupling between the two conductors. For this ``leaky'' quantum capacitor, we have derived general analytic expressions of the linear and second order nonlinear electrochemical capacitance within a first principles quantum theory in the discrete potential approximation. Linear and nonlinear capacitance coefficients are also derived in a self-consistent manner without the latter approximation and the self-consistent analysis is suitable for numerical calculations. At linear order, the full quantum formula improves the semiclassical analysis in the tunneling regime. At nonlinear order which has not been studied before for leaky capacitors, the nonlinear capacitance and nonlinear nonequilibrium charge show interesting behavior. Our theory allows the investigation of crossover of capacitance from a full quantum to classical regimes as the distance between the two conductors is changed

Comparison of Four Polymerase Chain Reaction Methods for the Rapid Detection of Human Fecal Pollution in Marine and Inland Waters

We compared the effectiveness of three PCR protocols for the detection of Bifidobacterium adolescentis and one PCR protocol for detecting Bacteroidales as indicators of human fecal pollution in environmental samples. Quantitative PCR indicated that a higher concentration of B. adolescentis DNA was recovered from sewage samples on the 0.2 μm filters compared to the 0.45 μm filters, and there was no evidence of qPCR inhibitors in the DNA extracts. With the Matsuki method (1999), B. adolescentis was detected only in undiluted sewage samples. The King method (2007) performed well and detected B. adolescentis in all of the sewage dilutions (from undiluted to 10−4). In contrast, the Bonjoch approach (2004) was effective at detecting B. adolescentis at lower dilutions (10−3) of sewage samples and it gave false positive results with some (3/8) pig fecal samples. Human-specific Bacteroidales (HuBacs) were detected in the lower diluents of sewage samples but was positive in pig (6/8) and cattle fecal samples. PCR detection of B. adolescentis in marine samples from Puerto Rico and freshwater samples from Georgia indicated that the PCR method of King et al. (2007) and the modified Layton method for HuBac were in agreement in detecting human fecal pollution in most sites

Efficient single-photon emission from electrically driven InP quantum dots epitaxially grown on Si(001)

The heteroepitaxy of III-V semiconductors on silicon is a promising approach for making silicon a photonic platform for on-chip optical interconnects and quantum optical applications. Monolithic integration of both material systems is a long-time challenge, since different material properties lead to high defect densities in the epitaxial layers. In recent years, nanostructures however have shown to be suitable for successfully realising light emitters on silicon, taking advantage of their geometry. Facet edges and sidewalls can minimise or eliminate the formation of dislocations, and due to the reduced contact area, nanostructures are little affected by dislocation networks. Here we demonstrate the potential of indium phosphide quantum dots as efficient light emitters on CMOS-compatible silicon substrates, with luminescence characteristics comparable to mature devices realised on III-V substrates. For the first time, electrically driven single-photon emission on silicon is presented, meeting the wavelength range of silicon avalanche photo diodes' highest detection efficiency