Intensity Vector Research Articles

Prevalence of sibling-species of Anopheles (Cellia) fluviatilis complex in Himachal Pradesh, India.

Malaria is one of the most infectious and life-threatening vector borne disease in the tropics. Climate change can significantly influence malaria epidemiology and expansion of malaria vectors to hilly regions of Himachal Pradesh in India, hitherto considered areas of low transmission. Entomological surveillance in Kangra district of Himachal Pradesh revealed high density of a proven efficient vector of malaria, Anopheles fluviatilis, but transmission intensity of malaria was found very low. It was therefore considered prudent to investigate the sibling-species composition of An. fluviatilis complex in Kangra valley to ascertain their role in transmission of malaria. The study was undertaken in six villages in Kangra district of Himachal Pradesh, India. A total of 4446 mosquitoes were collected during the one-year study period (2018) and processed in pools of ten for molecular characterization. DNA extraction and multiplex PCR was performed on 900 An. fluviatilis mosquitoes for differentiation of sibling-species. ELISA was used to detect Plasmodium falciparum and Plasmodium vivax circumsporozoite proteins in 3790 An. fluviatilis samples. Among prevalent mosquito species, An. fluviatilis was the predominant species constituting 69.5% of total mosquito collection. Sibling-species U was found in 92.22% and species T in 7.78% samples assayed. ELISA confirmed the absence of evidence of malaria parasite in any of the An. fluviatilis mosquitoes screened. Based on the difference in the sequences of conserved regions of the 28SrDNA, sibling-species U was confirmed as prevalent in the study villages. Study revealed that in Kangra district, An. fluviatilis sibling-species U is predominant followed by species T, and both are non-vectors. The absence of malaria parasite and zoophagic nature of An. fluviatilis established through blood meal analysis, confirmed that both U and T are non-vector sibling-species.

Problem of Determining the Anisotropic Conductivity in Electrodynamic Equations

For a system of electrodynamic equations, the inverse problem of determining an anisotropic conductivity is considered. It is supposed that the conductivity is described by a diagonal matrix σ(x) = {text{diag}}({{sigma }_{1}}(x),{{sigma }_{2}}(x), σ3(x)) with sigma (x) = 0 outside of the domain Ω = { x in {{mathbb{R}}^{3}}|left| x right| < R} , R > 0, and the permittivity ε and the permeability μ of the medium are positive constants everywhere in {{mathbb{R}}^{3}}. Plane waves coming from infinity and impinging on an inhomogeneity localized in Ω are considered. For the determination of the unknown functions {{sigma }_{1}}(x), {{sigma }_{2}}(x), and {{sigma }_{3}}(x), information related to the vector of electric intensity is given on the boundary S of the domain Ω. It is shown that this information reduces the inverse problem to three identical problems of X-ray tomography.

Loop Closure Detection by Using Global and Local Features With Photometric and Viewpoint Invariance.

Loop closure detection plays an important role in many Simultaneous Localization and Mapping (SLAM) systems, while the main challenge lies in the photometric and viewpoint variance. This paper presents a novel loop closure detection algorithm that is more robust to the variance by using both global and local features. Specifically, the global feature with the consolidation of photometric and viewpoint invariance is learned by a Siamese Network from the intensity, depth, gradient and normal vectors distribution. The local feature with rotation invariance is based on the histogram of relative pixel intensity and geometric information like curvature and coplanarity. Then, these two types of features are jointly leveraged for the robust detection of loop closures. The extensive experiments have been conducted on the publicly available RGB-D benchmark datasets like TUM and KITTI. The results demonstrate that our algorithm can effectively address challenging scenarios with large photometric and viewpoint variance, which outperforms other state-of-the-art methods.

Three-dimensional acoustic energy flow from rotating sound sources

A detailed study of the three-dimensional sound fields around a monopole point source in subsonic and supersonic rotation is investigated. We calculate the sound pressure, the acoustic velocity, as well as the instantaneous and time-averaged acoustic intensity fields with the advanced time approach. The advanced time approach is applied for sound sources at subsonic and supersonic rotation and yield comparable results as those obtained from the spherical harmonic series expansion method or the solution of the retarded time equation. Further, the direction of the time-averaged acoustic energy flow is derived from the acoustic intensity vectors. It is shown, that the direction of the energy flow path differs from the radial direction and depends on the rotational direction and rotational velocity. Those findings are useful, for example, to improve the acoustic absorption performance of sound absorbers and acoustic liners around turbomachines.

ECONDARY INFORMATION PROCESSING METHODS WHILE ESTIMATING THE SPATIAL ORIENTATION OF OBJECTS

The study is devoted to solving the scientific problem of ensuring unbiasedness and increasing the efficiency of assessing the spatial orientation of objects by applying new methods of secondary information processing in software and hardware components of computer systems. The paper describes a developed method for compensating for magnetic anomalies that affect magnetically sensi-tive sensors of the inclinometer rotation angles. It is based on recording the inclinometer readings and the angle of rotation of the drill pipe as it rotates in the mouth of well in a range of 360 degrees. This makes it possible to determine and further take into account the value of the magnetic deviation from the drill string in the readings of the inclinometer. A method is described for determining the parameters of a magnetic anomaly from an external stationary source of a constant magnetic field by using redundant information from the readings of inclinometery transducers in the mouth of well and at the point of assessment. This allows to expand the bound-aries and scope of magnetometric transducers in difficult conditions. Methods for calculating the desired azimuth, as well as the pa-rameters of the intensity vector of the magnetic anomaly are proposed. The errors of inclinometers based on sensor devices of various physical nature (fluxgates, gyroscopes, accelerometers), both rigidly fixed and with the use of gimbals pendulum suspensions, are considered. The factors influencing the bias of the estimation of the angles of the spatial orientation of the drilling tool, expressed through the Euler angles, are analyzed. The analysis took into account the effect of various reasons: deviations of the transducers' sensitivity axes from mutual orthogonality and the reference trihedron of the axes associated with the body; changes in the zero sig-nal and transfer ratios under the influence of temperature; non-identical electrical parameters; inaccurate installation of the pendulum gimbal sensor frames in the tilt plane and along the vertical of the place. The permissible boundary values of each of the given errors have been determined. Consideration of these errors can significantly increase the unbiasedness of the assessment of the position of the object in difficult conditions. The practical significance of the results presented in the paper is the development of software and hardware components for assessing the spatial orientation of objects on the basis of the designed inclinometers capable of operating in difficult operating conditions and having a small diameter of the protective casing. Similar software and hardware components for assessing the spatial orientation of objects can be used: for the construction of underground communications; for the assembly of large-sized and remote objects; for static sounding of soils; for monitoring the state of building structure elements during operation.

Intensity characterisation of polarisation vortex formation and evolution in ferroelectric nanofilms

ABSTRACT As a class of typical topological structures, polarisation vortexes were characterised by the intensity vector which is defined as the curl of the polarisation at their cores. Some phase field simulations were conducted on the lead titanate nanofilms to evaluate the effects of model size, temperature, traction, and curled electric field on the formation and evolution of polarisation vortex intensity quantitatively. The results showed that increasing size, lowered temperature and increasing traction could enhance the polarisation vortex intensity, curled electric field could change the vortex rotation direction, and compressive or tensile traction could change the vortex shape. Therefore, the polarisation vortex could be tuned by the given conditions of model size, temperature, traction, and curled electric field. This is helpful to improve the understanding and control of polarisation vortex structure.

A Prediction Method for Acoustic Intensity Vector Field of Elastic Structure in Shallow Water Waveguide

Compared with scalar sound field, vector sound field explained the spatial structure of sound field better since it not only presents the sound energy distribution but also describes the sound energy flow characteristics. Particularly, with more complicated interaction among different wavefronts, the vector sound field characteristics of an elastic structure in a shallow water waveguide are worthy of studying. However, there is no reliable prediction method for the vector sound field of an elastic structure with a high efficiency in a shallow water waveguide. To solve the problem, transfer functions in the waveguide have been modified with some approximations to apply for the vector sound field prediction of elastic structures in shallow water waveguides. The method is based on the combined wave superposition method (CWSM), which has been proved to be efficient for predicting scalar sound field. The rationality of the approximations is validated with simulations. Characteristics of the complex acoustic intensity, especially the vertical components are observed. The results show that, with constructive and destructive interferences in the depth direction, there could be quantities of crests and vortices in the spatial structure of time-dependent complex intensity, which manifest a unique dynamic characteristic of sound energy. With more complicated interactions among the wavefronts, a structure source could not be equivalent to a point source in most instances. The vector sound field characteristics of the two sources could be entirely different, even though the scalar sound field characteristics are similar. Meanwhile, source types, source parameters, ocean environment parameters, and geo parameters may have influence on the vector sound field characteristics, which could be explained with the normal mode theory.

Rainfall Symmetry Related to Moisture, Storm Intensity, and Vertical Wind Shear for Tropical Cyclones Landfalling over the U.S. Gulf Coastline

There continues to be a need to relate rainfall produced by tropical cyclones (TCs) to moisture in the near-storm environment. This research measured the distribution of volumetric rainfall around 43 TCs at the time of landfall over the U.S. Gulf Coast. The spatial patterns of rainfall were related to atmospheric moisture, storm intensity, vertical wind shear, and storm motion. We employed a geographic information system (GIS) to perform the spatial analysis of satellite-derived rain rates and total precipitable water (TPW), which was measured on the day before landfall. Mann–Whitney U tests revealed statistically significant differences in conditions when TCs were grouped by location. TCs moving over Texas entrained dry air from the continent to produce less rainfall to the left of their moving direction. As moisture was plentiful, rainfall symmetry during landfall over the central Gulf Coast was mainly determined by the vector of vertical wind shear and storm intensity. For landfalls over the Florida peninsula, interaction with a cooler and drier air mass left of center created an uplift boundary that corresponded with more rainfall on the TC’s left side when the moisture boundary represented by the 40 mm contour of TPW existed 275–350 km from the storm center.

Patterns of 1,748 Unique Human Alloimmune Responses Seen by Simple Machine Learning Algorithms.

Allele specific antibody response against the polymorphic system of HLA is the allogeneic response marker determining the immunological risk for graft acceptance before and after organ transplantation and therefore routinely studied during the patient's workup. Experimentally, bead bound antigen- antibody reactions are detected using a special multicolor flow cytometer (Luminex). Routinely for each sample, antibody responses against 96 different HLA antigen groups are measured simultaneously and a 96-dimensional immune response vector is created. Under a common experimental protocol, using unsupervised clustering algorithms, we analyzed these immune intensity vectors of anti HLA class II responses from a dataset of 1,748 patients before or after renal transplantation residing in a single country. Each patient contributes only one serum sample in the analysis. A population view of linear correlations of hierarchically ordered fluorescence intensities reveals patterns in human immune responses with striking similarities with the previously described CREGs but also brings new information on the antigenic properties of class II HLA molecules. The same analysis affirms that “public” anti-DP antigenic responses are not correlated to anti DR and anti DQ responses which tend to cluster together. Principal Component Analysis (PCA) projections also demonstrate ordering patterns clearly differentiating anti DP responses from anti DR and DQ on several orthogonal planes. We conclude that a computer vision of human alloresponse by use of several dimensionality reduction algorithms rediscovers proven patterns of immune reactivity without any a priori assumption and might prove helpful for a more accurate definition of public immunogenic antigenic structures of HLA molecules. Furthermore, the use of Eigen decomposition on the Immune Response generates new hypotheses that may guide the design of more effective patient monitoring tests.

Distance estimation of a sound source using the multiple intensity vectors.

The three-dimensional acoustic intensimetry employing multiple probe-modules are implemented for estimating the source distance by calculating the nearest intersection points of the vectors. The probe spacing, source localization error, and source distance affect the estimation error. It is found that the intensity vectors indicating the source location diverge in some directions due to the geometric singularity. Numerical and experimental tests are conducted with three probe-modules configured as an equilateral triangle on a plane. The result reveals that the large error due to geometric singularity can be significantly reduced by only excluding the corresponding vectors that cause the divergence.

Polarization and bandgap characteristics of monolayer black phosphoene in magnetic field

The effect of magnetic field on the polarization effect of black phosphorene is studied. The ground state energy and the relevant energy bandgap formula of carrier and carrier–phonon interaction system is derived in turn, and the effect of applied magnetic field on ground state energy and bandgap is also investigated, by the method of variational method, LLP unitary transformation method and linear combination operator method. When the substrate is given, the ground state energy and the relevant bandgap of the carrier–phonon interaction system changes with the magnetic induction intensity, phonon energy and cutoff wave vector. It can be shown by numerical calculation: The ground state energy and the relevant bandgap of the Hole and the Hole–phonon interaction system in black phosphorene increases with increase in magnetic induction intensity [Formula: see text]. The ground state energy of the Hole, Hole–phonon system and the relevant bandgap are different when the substrate is different. Under the action of a magnetic field, the ground state energy of the Hole and Hole–phonon system and bandgap decreases with increase in phonon energy and increases with increase in cutoff wave vector when the substrate is fixed.

Survival-relevant high-risk subregion identification for glioblastoma patients: the MRI-based multiple instance learning approach.

Given the glioblastoma (GBM) heterogeneity, survival-relevant high-risk subregions may exist and facilitate prognosis. The study aimed to identify the high-risk subregions on MRI, and to evaluate their survival stratification performance. The gross tumor regions (GTRs) were delineated on the normalized MRI of 104 GBM patients. The signal intensity of voxels from 104 GTRs was pooled as global intensity vector, and K-means clustering was performed on it to find the optimal global clusters. Subregions were generated by assigning back voxels that belonged to each global cluster. Finally, a multiple instance learning (MIL) model was built and validated using radiomics features from each subregion. In this process, subregions predicted as positive would be treated as high-risk subregions, and patients with high-risk subregions inside the GTR would be predicted as having short-term survival. After K-means clustering, three global clusters were fixed and 294 subregions of 104 patients were generated. Then, the subregion-level MIL model was trained and tested by 200 (71 patients) and 94 subregions (33 patients). The accuracy, sensitivity, and specificity for survival stratification were 87.88%, 85.71%, and 89.47%. Furthermore, 41 high-risk subregions were correctly predicted from patients with short-term survival, in which the median overlap rate of non-enhancing component was 60%. The stratification performance of high-risk subregions identified by the MIL model was higher than the GTR. The non-enhancing area on MRI was the most important component in high-risk subregions. The MIL approach provides a new perspective on the clinical challenges of glioma with coarse-grained labeling. • The performance of high-risk subregions was more promising than the GTR for OS stratification. • The non-enhancing component was the most important in the high-risk subregions.

Reduction of error and expansion of spatial range of measurement of the electrical field strength sensor

The article is directed to improving the metrological characteristics of the previously investigated multi-element planar electro-induction sensor of the components of the electric field intensity vector. For this purpose, its mathematical model is made and analytic expression is obtained for error taking into account design parameters of sensor responsible for its error in nonuniform field and spatial range of measurement. Using mathematical model, geometric dimensions of sensitive elements of sensor are optimized in terms of minimum error and maximum of spatial measurement range. This allowed the following technical results to be obtained. At optimal parameter b = h/L (h - spacing between edges of sensor and electrode, L-linear dimension of sensor) of sensor error from field nonuniformity does not go out beyond 3% in all spatial range 0 ≤ a ≤ 0.2 (a = L/d; d-distance to field source). Thus, the sensor can be used for measuring at distances from the source of the field d equal to five linear dimensions L (d ≈ 5L).

Propagation properties of partially coherent anomalous hollow beams in quadratic-index media

Based on the generalized diffraction integral formula, analytical propagation expressions for a partially coherent anomalous hollow beam (AHB) propagating through a quadratic-index medium are derived. The distributions of intensity and Poynting vector for a partially coherent AHB through the quadratic-index medium are numerically and theoretically studied. It is found that the intensity and Poynting vector of the partially coherent AHB take on a periodical change. The evolution properties of the partially coherent AHB in a quadratic-index medium are closely relevant to its transverse coherence width and the quadratic-index parameter of media.

Estimation of seabed properties and range from vector acoustic observations of underwater ship noise.

The Intensity Vector Autonomous Recorder (IVAR) simultaneously measures acoustic particle velocity and pressure. IVAR was deployed during the 2017 Seabed Characterization Experiment (SBCEX) with the primary objective to study sound propagation in fine-grained, muddy sediments. In this study a Bayesian inversion framework is applied to ship underwater noise recorded by IVAR. The data are relative phase of pressure and vertical particle velocity, a quantity that is independent of the ship noise source spectrum. Inversion estimates for the sediment layer and underlying basement properties are in agreement with other reports from SBCEX.

A type of bi-stable spiral wave in a single-period oscillatory medium

A new type of spiral wave caused by the pitchfork bifurcation of a limit cycle is reported, which may exist in ecosystems containing two (or more) species that are not symbiotic. The dynamical behavior of the spiral wave is explained by a superposition principle of disturbance intensity vectors in oscillatory media. This type of spiral wave is characterized by a slow-moving line-defect that passes through the spiral center. The line-defect disturbs the local phase waves, whose disturbance can be superposed with the disturbance coming from the spiral core. This superposition principle of disturbance intensity vectors provides a new theory and method for studying the pattern formation in oscillation media. On the one hand, our findings shed light on the dynamics of the pattern formation; on the other, we predict a type of spiral wave which has not been found in nature or laboratories to date, and provide directions and guidances for ecological researches about ecosystems containing two (or more) species that are not symbiotic.

Performance Analysis of Cost-Effective Miniature Microphone Sound Intensity 2D Probe.

This article presents the functional properties of modified versions of the 2D pressure–pressure intensity probe allowing us to determine the vector of sound intensity on a plane using a mechatronic system with one or two miniature electret microphones. The introduction contains basic information about the application areas of the sound intensity and its measurement problems. Next, the principle of operation of the probes and the construction of the prototype measurement system are described. It was subjected to comparative analysis for the stability of obtained results and accuracy of directional characteristics in free field conditions. For this purpose, experiments were conducted to analyze the flow of acoustic power in an anechoic chamber using both (one- and two-microphone) probes. The results were used for a comparative metrological analysis of the described methods and to indicate the advantages and disadvantages of both constructions. The next part of the article presents an experiment concerning the measurement of the sound intensity impulse response of a room, which is an example of practical use of the probe to analyze reflections in the room, which can be used in sound engineering and architectural acoustics.

Effect of a Strong Electromagnetic Wave on the Conductivity of β-Ga2O3

The conductivity of gallium oxide affected by a strong electromagnetic wave and an external dc electric field with co-directed vectors of intensity is studied, based on an analysis of the quantum kinetic equation that considers the scattering of electrons by charged impurities. It is shown that at temperatures of around 100 K, the main contribution to the conductivity comes from elastic scattering processes, while those with the absorption and emission of photons become important only at amplitudes of wave intensity of around 106 V cm−1.

Multu-electrode sensors of the components of the electric field intensity vector in the form of the disk made of conductive material

The article investigates a multi-element disk sensor of the components of the low-frequency electric field intensity vector, manufactured using new technologies. The sensor is suitable for measuring the intensity of electric fields adversely affecting a person. In this regard, the problem solved in the article is relevant. The results of the study made it possible to create such a sensor, evaluate its metrological characteristics and establish their dependence on the degree of homogeneity of the electric field. The established relationship between the sensor error and the degree of heterogeneity of the electric field makes it possible to determine the spatial range of measurement from a given error or to establish the sensor error from a given spatial range of measurement. For example, a sensor error of 3% corresponds to the spatial measurement range a, determined by the distance to the field source from 0 R to 5·R (a ≤ 0.2), where R is the radius of the disk of the base of the sensor.

Predictive models for identification of parameters of seismic vibrations by applying the theory of covariance functions

The paper analyses an opportunity to develop predictive models for identification of parameters of seismic vibrations by applying statistical processing of measurement data. The calculations used measurement data arrays according to vectors E, N and Z obtained from four seismic stations (India EVBH, Indonesia LUWIBH, Italy CERABN and Turkey BNHBH). The Doppler method and the theory of covariance functions were applied for analysing the measurement data arrays. The trend of seismic vibration intensity vectors was estimated by applying the least-squares method. In addition, the said procedure partially eliminates random errors of the measurement data from the stations. Using the intensity variation of seismic vibration vectors E, N and Z on the timescale, the estimates of autocovariance and cross-covariance functions of seismic vibration vectors were calculated by changing the quantised interval on the time scale. The average values of parameter z in the Doppler formula were calculated according to the created formula by applying the expressions of cross-covariance functions of the algebraic addition of the relevant vectors and a single vector. By applying the values of parameter z from the Doppler formula, the approximate value of the velocity of reciprocal movement of seismic vectors was calculated. In the calculations, the software developed on the basis of the MATLAB program package operators was applied.