Horizontal Transfer Functions Research Articles

Detection of NDM-1 and OXA-10 Co-Producing Providencia rettgeri Clinical Isolate.

The coexistence of blaNDM-1 with other resistance determinants is rarely reported for Providencia rettgeri. Therefore, this study investigates the phenotypic and genetic characteristics of a multidrug-resistant P. rettgeri strain YQ150713. P. rettgeri YQ150713 was identified as carrying blaNDM-1. S1-pulsed-field gel electrophoresis (S1-PFGE), Southern blotting, and conjugation experiments were used to determine plasmid characteristics. An antimicrobial susceptibility test was conducted. The complete genomic sequence of YQ150713 was obtained using Illumina NovaSeq 6000 and Oxford nanopore platforms.To further characterize the phylogenetic structure of P. rettgeri YQ150713, average nucleotide identity (ANI) and phylogenetic analyses were conducted. The S1-PFGE, Southern blot, and conjugation assays have confirmed that the isolate P. rettgeri YQ150713 contains the blaNDM-1 gene on a conjugative plasmid pYQ150713-NDM-1. Antimicrobial susceptibility testing has indicated that strain YQ150713 was resistant to various common antibiotics, except aztreonam and fosfomycin. Bioinformatics analysis has further shown that pYQ150713-NDM-1 was a novel plasmid with a size of 265,883 bp, and blaNDM-1 and blaOXA-10 were co-located on it. Phylogenetic analysis suggesting P. rettgeri has spread widely throughout the world. In this study, blaNDM-1 and blaOXA-10 were co-localized on a novel plasmid pYQ150713-NDM-1 with a horizontal transfer function. To reduce the risk of the dissemination of such P. rettgeri isolates in clinical settings, more surveillance will be required in the future.

A new empirical method for obtaining horizontal site amplification factors with soil nonlinearity

AbstractCurrently, the theoretical prediction of soil amplification considering nonlinear soil behaviors can be implemented through nonlinear analysis of soil layers in time domains. However, in such theoretical methods, we need detailed velocity information down to the seismological bedrock and nonlinear properties of sediments, which are challenging to obtain in a wider area for a scenario‐type seismic risk evaluation. Recently, using diffuse‐field theory, we found that the horizontal‐to‐vertical spectral ratio of Earthquake (EHVR) is the ratio of the S‐wave horizontal transfer function with respect to the P‐wave vertical transfer function with the vertical incidence from the seismological bedrock with a coefficient for HVRs at the bedrock. Therefore, if there is no significant nonlinearity in the P‐wave vertical transfer function during strong shaking, we can regard soil nonlinearity emerging on the EHVR as the nonlinearity of the S‐wave horizontal amplification. In this study, we tried to distinguish the difference between the EHVRs in the linear and nonlinear cases, quantify the difference, and utilize a creative empirical approach to acquire the S‐wave horizontal amplification factors with soil nonlinearity to improve the quality of strong motion prediction in the near field in the future.

Complete-Genome Sequencing and Comparative Genomic Characterization of an IMP-4 Producing Citrobacter freundii Isolate from Patient with Diarrhea.

BackgroundCitrobacter freundii is the most common class of pathogens in the genus Citrobacter and is an important pathogen associated with certain underlying diseases or immune dysfunction. The aim of this study was to elucidate the resistance mechanism of clinically derived carbapenem-resistant C. freundii isolate and to characterize the genetic environment and delivery pattern of the IncN1 plasmid carrying the blaIMP-4 gene from C. freundii isolate.Materials and MethodsWe identified a clinical isolate of C. freundii L91 carrying blaIMP-4 and performed phylogenetic analysis by whole-genome sequencing. The complete genomic sequence of L91 was obtained using the Illumina HiSeq 4000-PE150 and PacBio RS II platforms. Antimicrobial susceptibility testing was determined by the VITEK 2 system. Plasmid characteristics were presented by S1-pulsed-field gel electrophoresis (PFGE), Southern blotting and conjugation experiments.ResultsS1-PFGE, Southern blot and conjugation assay confirmed the presence of blaIMP-4 genes on a conjugative plasmid in this isolate. C. freundii L91 and transconjugant L91-E. coli 600 strains both showed resistance to carbapenems. In silico analysis further showed that pIMP-4-L91 is an IncN1 plasmid with a length of 51,042 bp. Furthermore, blaIMP-4 gene was found encoded in the blaIMP-4-qacG2-aacA4-catB3 cassette array within a class 1 integron. A conserved structure sequence (ΔISKpn27-blaIMP-4-ΔISSen2-hp-hp-IS6100) was found in the upstream and downstream of the blaIMP-4.ConclusionWe performed a comprehensive phylogenetic analysis of carbapenemase-resistant C. freundii and elucidated the resistance mechanism of clinically derived C. freundii L91. Not only that, we also found that the blaIMP-4 gene is located on the IncN1 plasmid and has a horizontal transfer function and a certain ability to spread. To lower the risk of the dissemination of such C. freundii isolates in clinical settings, more surveillance is needed in the future.

Vertical and Horizontal Seismic Isolation Performance of the Advanced Virgo External Injection Bench Seismic Attenuation System

During the combined commissioning and science run of Virgo in 2010, an extensive noise study revealed that vibrations of some of the injection/detection optics on the external injection bench (EIB) made a significant contribution to the interferometer's noise budget. Several resonances were identified between 10 and 100Hz of the EIB support structure and between 200 and 300Hz of the optics mounts. These resonances introduced a significant amount of beam jitter that would limit the sensitivity of Advanced Virgo. This beam jitter needed to be reduced for Advanced Virgo to reach its full potential. To eliminate this noise source we developed a seismic attenuation system to isolate the EIB from ground vibrations: EIB-SAS. It employs vertical and horizontal passive seismic filters based on negative stiffness technology to attenuate seismic noise by 40dB above 10Hz. The isolation capabilities of the system have been characterized up to 400Hz with the aid of a custom designed piezoelectric actuated shaking platform. The results of the vertical and horizontal transfer function measurements are presented.

Three-dimensional geomagnetic response functions for global and semi-global scale induction problems

SUMMARY Features of the geomagnetic response functions due to a 1000 km scale isolated conductivity anomaly embedded in a radially symmetric Earth with a surface heterogeneous layer were studied by three-dimensional (3-D) global forward modelling in order to understand the fundamental characteristics of the response functions for period of about 1–100 d and to examine the validity of 1-D like treatment for some of the responses. The geomagnetic deep sounding (GDS) response function has dipolar sensitivity to the lateral electrical conductivity contrast, while the D response (ratio of the eastward to northward component of geomagnetic field variation) shows the 3-D effect as a quadrupole-like distribution having peaks outside of heterogeneity. Although GDS and D responses were used in global induction studies in the past, we examined if the horizontal transfer function (HTF), the ratios of the geomagnetic north components at a station to those at other reference station, has enough sensitivity to the mantle heterogeneity and if it is worth to be included in global conductivity soundings. Modelling result shows that the spatial distribution of anomalous HTF is somewhat similar to the projection of heterogeneity on the surface so that the information different from those due to the GDS and D responses can be obtained by the HTF. The signatures of the conductivity heterogeneity in the GDS, D and HTF are detectable if the conductivity of the 1000-kmscale heterogeneous block is more than twice as conductive or five times as resistive as the surrounding medium. Both cases have an induction number of about 0.8. The anomalous parts of the response functions due to multiple heterogeneous bodies can be represented very well by the sum of those due to each isolated heterogeneity, if an induction number of each anomalous scattering body is less than about 2. Although the linearity breaks down when the induction number is larger, the difference between them is not significant compared with typical observational error of corresponding response functions. This implies that the sensitivity to an isolated block can be applied to discuss the resolution of multiple blocks, such as conductivity distribution having checkerboard pattern, and vise versa, in 3-D inversions. The distribution of 3-D GDS response implies that 1-D like treatment of the GDS response, such as compiling single station 1-D conductivity profiles to discuss regional differences of conductivity and correcting the static shift of magnetotelluric responses with converted GDS response, may cause serious problem if lateral heterogeneity is not negligible. This shows the necessity of modelling and analyses, which are compatible with 3-D structure.

Measured and Predicted Solute Transport in a Tile Drained Field

Most solute transport measurement techniques are tedious and require extensive soil excavation. A field experiment was conducted to evaluate whether surface transport properties determined by a nondestructive time domain reflectometry (TDR) technique could be used to accurately predict tile flux concentrations. A 14 by 14 m field plot selected above a 1.1‐m deep tile drain was studied. Low electrical conductivity (EC) water was sprinkled on the plot surface, and after reaching a steady‐state condition, a pulse of calcium chloride solution (16.3 cm) with an EC of 23 dS m−1 was applied through the same sprinklers. Time domain reflectometry equipment was used to record the change in EC of surface (∼ top 2 cm) soil at 45 locations. The EC of the tile drainage flow was measured continuously with an EC probe. The surface convective lognormal transfer (CLT) function parameters, log mean irrigation depth, μI, and its standard deviation, σI, were found to be 3.44 and 0.94 [ln(cm)], respectively, for a reference depth of 110 cm. These surface parameters were used in a one‐dimensional (1‐D) CLT model and in a two‐dimensional (2‐D) model (CLT vertical function combined with exponential horizontal transfer function) to predict the tile flux concentrations. The 1‐D CLT model predicted an earlier arrival time of chemicals to the tile drain than observed values. The root mean square error, RMSE, of the 1‐D CLT predictions was 0.123, and the coefficient of efficiency, E, was −0.47. The 2‐D model predictions of tile flux concentrations were similar to the observed values. The root mean squared errors (RMSE) and E were 0.023 and 0.94, respectively. The findings suggest that in this field soil, the surface solute transport properties determined by TDR could be combined with a 2‐D transport model to make reasonable predictions of tile flux concentrations.

Integrated modeling of EM response functions from Peninsular India and Bay of Bengal

Existing sets of magnetovariational data from the large numbers of sites distributed across the peninsular India and those in the Bay of Bengal are reanalysed to obtain inter-site vertical and horizontal field transfer functions. Maps of induction arrows relocate the earlier reported conductive zones beneath the Palk-Strait and a regional scale anomaly in the offshore region, immediately southwest of the southern tip of Indian Peninsula, named South India Offshore Conductivity Anomaly (SIOCA). Period dependence of the induction arrows suggests that with increasing period SIOCA tends to control the induction pattern over the entire peninsula. Presentation of the horizontal transfer functions in the form of ellipses of anomalous currents helps to characterize the period and spatial behaviour of horizontal fields at seafloor sites. Integrated thin sheet modeling of the on-land and seafloor induction features suggest that the greater part of the anomalous behaviour of the horizontal fields at seafloor sites can be attributed to the shielding effects due to seawater. The weak anisotropic behaviour of the horizontal fields at selected sites can be explained in terms of the concentration of the induced currents in the sediment filled troughs on either side of the 85°E Ridge. Several lines of geophysical evidence favour the hypothesis that SIOCA, low velocity zone, low magnetization anomaly, all centered near the southern tip of the India, are the relics of the interaction of Marion Plume outburst with Indian lithosphere.

The distribution characteristics of short period geomagnetic variations in Shaanxi region

In order to investigate the characteristics of short period geomagnetic variations in Shaanxi region, a temporary measurement profile from Shiquan in the southern part of Shaanxi to Ningxian in Gansu was set up in September of 1996 to carry out simultaneous observation of three-component geomagnetic variations along the profile. The vertical transfer functions, the horizontal transfer functions and the spectral component’s relationship of each period segment at each site in the period range from 3 min to 2 h were statistically calculated. Random data theory was applied to the data processing for reference, which led to a relatively good result. Analysis of the data point out that short period geomagnetic variations are affected by the regional influence of underground anomalous inductive current concentration between Wugong and Qianling in the nearly E-W direction and by the influence of local inductive current in nearby area of measurement site. The main distribution feature is that vertical transfer functions reverse between Wugong and Qianling and frequency responses of the transfer functions have maximum at period about 20 min.

Topographic site effects and HVSR. A comparison between observations and theory

Abstract We present a comparison between observed and predicted amplification on a topographic feature. Our data come from an ad hoc experiment carried out during the summer of 1989, in Epire (Northern Greece). Ten digital, autonomous, three-component stations recorded a total of 68 small earthquakes. As these data were inadequate to compute empirical transfer functions using the standard spectral ratio (SSR) technique, we explored the possible use of horizontal-to-vertical spectral ratios (HVSR). First, we compare HVSR computed from theoretical transfer functions for incident P, SV, and Rayleigh waves with the horizontal transfer function for each incidence type. Second, we compute HVSR for our weak-motion data set and show that the results are stable, with a scatter not larger than that usually accepted in SSR studies. We observe significant differences between N-S and E-W motion. When we compare HVSR with theoretical transfer functions, we obtain a better agreement for SV motion than for SH motion. Amplification levels are similar between HVSR and predicted amplification, even for the SH case. This suggests that discrepancies that have been signaled for the topographic amplification between observations and predictions could be due to site effects being present in the reference station used to computed SSR. Our results support the use of HVSR to determine topographic site effects. Thus, HVSR may have a large potential to evaluate site effects in a wider variety of geological conditions than previously thought, without the shortcomings of SSR. Finally, we show that HVSR computed from noise recordings gives a reasonable estimate of HVSR computed from weak-motion data. Although this conclusion should be better substantiated, our preliminary results are encouraging.

Geomagnetic Transfer Functions in Japan Obtained by First Order Geomagnetic Survey.

Repeated measurements of the Earth's time varying magnetic field have been made across Japan by the Geographical Survey Institute. Such measurements are known as a first order geomagnetic survey. There are 105 geomagnetic stations located uniformly across the whole of Japan. Since 1987, triaxial fluxgate magnetometers have been used to obtain one-minute data at almost all stations. From the geomagnetic data, transfer functions were determined for each station. Traditional vertical field transfer functions of wide period range (from 4 min to 128 min) were obtained, making use of the interstation method. Additionally, we calculated transfer functions for the horizontal field. The distribution of the transfer functions can be used to form a reference map of geomagnetic induction in Japan. Moreover, the distribution of the horizontal transfer functions in Japan has been examined for the first time. After eliminating the effect of the sea water using thin-sheet models, large regional anomalies are found to remain. These anomalies are diagnostic of the resistivity structure and show patterns of current channeling in Japan.

Vertical and horizontal transfer function measurements on a magnetic gas spring

A magnetic gas spring (MGS) has been developed to be the filter element of the super attenuator (SA), the device designed to support the optical components of the gravitational interferometric antenna VIRGO. Measurements have been performed on a MGS in order to study the resonance structure of the attenuation spectra in both the vertical and horizontal directions. Results guarantee an attenuation of at least 40 dB almost everywhere from 10 Hz to 1 kHz. By using experimental data the calculated performances of the SA turn out to be quite adequate for the VIRGO project requirements.

Magnetovariational study over a seismically active area in the Deccan Trap province of western India

This paper presents the results of a magnetovariational study undertaken over a basalt-covered region of western India which has been experiencing a swarm of seismic activity since early 1986. The most striking feature of the transient variations is the anomalous enhancement of the east-west ( Y) component at stations bounding the seismically active belt. From the nature of the horizontal transfer functions and the anomalous induction arrows, it is inferred that this behaviour is related to the presence of a resistive body embedded in a north-south-oriented conductive belt. Consistent with an evolutionary model of Deccan volcanism and other geophysical data, it is suggested that the central resistive block coincident with the concentrated belt of earthquake epicentres represents either a dormant volcanic plug or a plutonic body rooted in upwarped conducting mantle. To account for the phase relationship between the anomalous Y variations and the normal north-south ( X) variations, it is proposed that the upwarped asthenosphere, with its associated high geothermal anomaly, acts as a conducting path to channel induced current from the region of the Cambay triple junction located towards the northwest of the array. The existence of the strong induced currents in the region of the triple junction conforms with the induction arrow pattern observed at the array stations.

Performance of a gas spring harmonic oscillator

The characteristics and the performances of a gas spring, to be used in the future in a three-dimensional multiple attenuation system, designed to support the heavy test masses for a low-frequency gravitational wave interferometric antenna, are presented. This multiple system is expected to attenuate 10−9 (10−11) at 10 Hz in the vertical (horizontal) direction. This experiment, in which masses up to 430 kg have been levitated, has shown that the height of the resonance peaks in the gas spring vertical and horizontal transfer functions should not prevent us from obtaining the required high attenuation factors. A gas temperature feedback system, for the gas volume control, has given satisfactory results.

Spectral Transfer Functions for a Three-Component Sonic Anemometer

The transfer functions which describe the effect of line averaging and path separation on the response of a three-component sonic anemometer have been computed specifically for the Kaijo-Denki PAT 311. These computations differ from the previous work of Kaimal et al., by accounting for the two parallel paths which compose each measurement axis and for the vertical separation of the two horizontal axes. There is only a minor additional attenuation of response for the vertical wind component due to the measurement axis being composed of two paths rather than one. However, the differences between the horizontal transfer functions calculated here and those presented by Kaimal et al. are significant and could be important for correcting sonic spectra in the inertial subrange.

Short-period P-coda characteristics in the eastern Canadian Shield

Abstract The short-period P-coda of eight earthquake events (recorded on magnetic tape) and one underground nuclear event (standard Canadian network seismogram) are analyzed in both the time and frequency domains in order to determine the transmission characteristics of the crust in the eastern section of the Canadian Shield. Surface particle motion diagrams indicate that there is appreciable anomalous P-S conversion in this region, starting at the base of the Labrador trough and extending to the upper mantle. The spectral ratio test, when applied to short-period records, is found to be capable of resolving thin crustal layers only. Coherency studies of teleseismic events recorded over a lateral distance, the same order of magnitude as the thickness of the crust in this region, show that the coherency (0.5 average) is much lower for the horizontal component than for the vertical component and also does not appear to vary appreciably with epicentral distance, whereas the vertical component does. Since for many of the records the signal-to-noise ratio of the vertical and horizontal components is comparable, these results indicate the possibility of the horizontal transfer function being more unstable over this region than the vertical transfer function. From these observations it is concluded that (1) in the region of the eastern Canadian Shield where there is a surface layer of Proterozoic sediments about one km thick overlying basement rocks, the short-period body-wave transmission characteristics are more similar to those of the western Canada sedimentary basin in central Alberta than to those of the western part of the Canadian Shield near Yellowknife, Northwest Territories and (2) in order to resolve both thin and thick crustal layers by means of the spectral ratio test, both short- and long-period records of the P coda are required.

An investigation and application of the crustal transfer ratio as a diagnostic for explosion seismology

Abstract Because the spectral behavior of seismic first arrivals contains much information about the nature of the transmission path, the Thomson-Haskell matrix formulation for the response of layered systems has received much attention. In particular, the transfer ratio, i.e., the ratio between the vertical and horizontal transfer functions, invites study because it can be compared with the ratio spectrum, an observable quantity, independent of the source function and characterizing the model alone. An investigation of this quantity as a function of the parameters in the layered model shows that it is insensitive to densities in the model, that the shear velocities in the model are less critical than the layer thicknesses and compressional velocities, and that it is probably impossible to numerically invert the problem uniquely, that is, to find a unique model whose calculated transfer ratio matches the observed ratio spectrum of a seismogram. The transfer ratio can provide a useful and sensitive constraint on models derived from other methods, however. By searching the parameter space around several different types of models, models which satisfy observed ratio spectrums in the least square sense can be found. Inspection of these models' transfer ratios and response functions discriminates between model types which are acceptable and those which are not.