Horizontal Ray Research Articles

Successful management of neonatal gastric perforation in Tripura medical college and Dr. BRAM teaching hospital-a rare case report

Gastric perforation in the newborn is a rare surgical emergency in our practice area; nevertheless, since the earlier it is diagnosed, the better the prognosis, it is a possibility that we must be aware of. Perforation would be suspected in an infant with severe abdominal distension and diagnosis is confirmed with simple abdominal X-rays, including anteroposterior and lateral projections with horizontal ray, on which pneumoperitoneum will be shown. We report the case of a neonate diagnosed with gastric perforation at 72 hours of age who underwent a successful surgical intervention and was able to go home clinically healthy 14 days later.

On the measurement ofSdiff splitting caused by lowermost mantle anisotropy

SUMMARYSeismic anisotropy has been detected at many depths of the Earth, including its upper layers, the lowermost mantle and the inner core. While upper mantle seismic anisotropy is relatively straightforward to resolve, lowermost mantle anisotropy has proven to be more complicated to measure. Due to their long, horizontal ray paths along the core–mantle boundary (CMB), S waves diffracted along the CMB (Sdiff) are potentially strongly influenced by lowermost mantle anisotropy. Sdiff waves can be recorded over a large epicentral distance range and thus sample the lowermost mantle everywhere around the globe. Sdiff therefore represents a promising phase for studying lowermost mantle anisotropy; however, previous studies have pointed out some difficulties with the interpretation of differential SHdiff–SVdiff traveltimes in terms of seismic anisotropy. Here, we provide a new, comprehensive assessment of the usability of Sdiff waves to infer lowermost mantle anisotropy. Using both axisymmetric and fully 3-D global wavefield simulations, we show that there are cases in which Sdiff can reliably detect and characterize deep mantle anisotropy when measuring traditional splitting parameters (as opposed to differential traveltimes). First, we analyze isotropic effects on Sdiff polarizations, including the influence of realistic velocity structure (such as 3-D velocity heterogeneity and ultra-low velocity zones), the character of the lowermost mantle velocity gradient, mantle attenuation structure, and Earth’s Coriolis force. Secondly, we evaluate effects of seismic anisotropy in both the upper and the lowermost mantle on SHdiff waves. In particular, we investigate how SHdiff waves are split by seismic anisotropy in the upper mantle near the source and how this anisotropic signature propagates to the receiver for a variety of lowermost mantle models. We demonstrate that, in particular and predictable cases, anisotropy leads to Sdiff splitting that can be clearly distinguished from other waveform effects. These results enable us to lay out a strategy for the analysis of Sdiff splitting due to anisotropy at the base of the mantle, which includes steps to help avoid potential pitfalls, with attention paid to the initial polarization of Sdiff and the influence of source-side anisotropy. We demonstrate our Sdiff splitting method using three earthquakes that occurred beneath the Celebes Sea, measured at many transportable array stations at a suitable epicentral distance. We resolve consistent and well-constrained Sdiff splitting parameters due to lowermost mantle anisotropy beneath the northeastern Pacific Ocean.

Metro gauge inspection system based on mobile laser scanning technology

Detecting metro gauge is very important for the safe operation of the subway. In this study, we design a low-cost metro tunnel mobile scanning system (MDS-TJ-1), which integrates a laser profile scanner with an inertial measure unit and an odometer to provide positioning and attitude parameters of the trajectory. The Lagrange interpolation is used to accomplish the time unification of different sensors. A dynamic alignment scheme for profile scanner is proposed based on the designed plane reflector target with high reflectivity. The error accumulation of the odometer is corrected by recognising the tunnel longitudinal joints, and finish the multi-source data fusion. The horizontal ray method is developed to process the metro gauge inspection. The experiment results show that the alignment accuracy of scanner is within 8 mm, the inner coincidence of the point cloud is within 3 cm, and the average error of the gauge inspection is 7.8 mm.

Study on Impulse Current Dispersal and Structure Optimization of Grounding Electrode Structure of Tower

In this paper, a simulation model for soil nonlinear ionization is established, and the actual grounding electrode of the project is studied. Results show that for radial grounding electrodes, the horizontal ray conductor has better current dispersal than the middle conductor. Therefore, when improving the horizontal radiating grounding structure, short conductors should be added to the horizontal ray conductors. According to the impulse current dispersal regularity, two improved methods are proposed. After simulation, the improved grounding resistance is getting smaller, so that the improvement scheme is correct. Finally, two improved methods are applied to the engineering grounding electrode, and the potential and grounding resistance of improved grounding electrode are all reduced, so the improved method is effective.

Properties and enhancements of robust likelihood CUSUM control chart

The properties of RLCUSUM control schemes used to monitor contaminated normally distributed processes are evaluated.An optimal design procedure for RLCUSUM control schemes is given. And several enhancements to RLCUSUM are considered.Compare robust likelihood CUSUM control charts with conventional CUSUM and GCUSUM, and conclude their pros and cons.Fast initial response feature is included, that makes the RLCUSUM control schemes more sensitive to start-up cases.An application is used to illustrate the implementation of RLCUSUM control schemes. In practice, the robust-likelihood cumulative sum (RLCUSUM) control charts, using truncation of the log-likelihood underpinnings of the CUSUM to ensure robust performance, which perform well to detect small shifts in the mean of heavy-tailed processes and have the ability to discount outliers. In this article, we evaluate the properties of RLCUSUM control schemes used to monitor the mean of contaminated normally distributed processes. An optimal design procedure for RLCUSUM control schemes is given, in addition, several enhancements to RLCUSUM are considered. These include a fast initial response feature that makes the RLCUSUM control schemes more sensitive to start-up cases, three types of truncation of RLCUSUM, which are cut off by horizontal ray, horizontal segment and oblique line respectively against both large and small shifts in a non-normality process. An extensive comparison with the conventional CUSUM and generalized likelihood ratio CUSUM (GCUSUM) in terms of average run length (ARL), shows that the RLCUSUM is more robust than the conventional CUSUM and GCUSUM control charts for its ARLs are monotonous against the process mean. Especially, the oblique line truncated RLCUSUM control chart has the best overall performance in the various cases of shifts. A final application based on monitoring packing 250g containers is used to illustrate the implementation of RLCUSUM control schemes.

Three-dimensional modeling in global acoustic propagation

The ocean is nearly transparent for acoustic propagation at low frequencies (<100 Hz), leading to the detection of signals (seismic events, volcanoes, and man-made signals) at distances as large as the ocean basin. Historically, basin acoustic modeling has neglected out-of-plane effects and has been performed with the model computed in the range/depth plane for multiple radials following geodesics (Nx2D). Both oceanographic and bathymetric features can lead to out-of-plane effects. In this paper, a summary of computational approaches to this problem will be presented, including vertical-mode, horizontal ray hybrid approaches, and full-3D Parabolic Equation modeling. Out-of-plane effects include refraction and diffraction—which have different effects as well as different approaches to modeling. Experiments where 3D propagation effects were significant will be presented within this context, including Perth-Bermuda (1960), the Heard Island Feasibility Test (1993), and a recent seismic tomography test off the coast of Japan (2015). Three physics mechanisms will be addressed: horizontal deflection due to mesoscale eddies and fronts, reflection from islands (refraction), and diffraction behind bathymetric edges.

Assessing Sagittal Rotation on Posteroanterior Chest Radiographs: The Effect of Body Morphology on Radiographic Appearances

BackgroundChest radiography is one of the most commonly performed radiographic examinations worldwide. Routinely acquired in the erect posteroanterior (PA) position, a chest radiograph displays substantial amounts of medical information when accurate patient positioning is achieved. However, a rotated PA chest radiograph has reduced diagnostic quality and appearances may mask or mimic chest pathology. Radiographic assessment of patient rotation around the sagittal plane has traditionally been undertaken by assessing the distance between the medial end of the clavicles and a line drawn through the spinous processes at the level of the clavicles. This approach continues to be advocated in radiographic technique textbooks internationally although no identified author has provided criteria to determine when a rotated PA chest radiograph should be repeated; determined the relationship between perceived clavicle to spinous process distance and actual degree of patient rotation; or considered the impact of body morphology, in particular the anteroposterior thoracic diameter, on radiographic appearances of rotation. ObjectivesTo determine the impact of anteroposterior chest diameter on radiographic appearances of sagittal rotation on PA chest radiographs. DesignExperimental study. Methods and SettingsSixty computed tomography thorax examinations, stratified for gender, were reviewed and data aggregated to determine average anteroposterior (AP) thoracic dimensions. A bespoke experimental unit was constructed specifically to enable testing of the impact of sagittal rotation on radiographic appearances. The experimental unit was situated within a calibrated circular frame enabling 360° rotation at 1° intervals around a central rotational point. The experimental unit components were varied in 1 cm intervals from 9 cm to 15 cm around the central rotation point to reflect varying AP chest diameters. At each interval, images were acquired at 0, 2, 5, 7, 10, and 15° sagittal rotation using a horizontal central ray, consistent centring point, and a source-image distance of 180 cm. ResultsA clear linear relationship between AP thoracic diameter and the radiographic appearances of sagittal rotation was noted. Considering significant rotation to be when the medial end of clavicle overlaps the spinous process on the radiographic image, this appearance occurred at a much smaller degree of rotation on wide AP thoracic diameters (15 cm, 5°) than narrower AP thoracic diameters (9 cm, 10°). ConclusionsThe routine application of the distance between the medial end of the clavicles and a line drawn through the spinous processes at the level of the clavicles as a method of assessing degree of sagittal rotation, diagnostic image quality, and need for repeat is flawed. Persistence in the application of this approach without cognisance of the impact of body morphology on radiographic appearances will result in persons with large AP thoracic diameters being more likely to have a PA chest radiograph repeated for a specified degree of rotation than persons with smaller AP thoracic diameters.

Correlation between generalized joint hypermobility and hallux valgus

Purpose: to evaluate correlation between generalized joint hypermobility, forefoot deformities and elasticity of the first ray of the foot. Material and methods. We examined 138 patients with complaints related with deformities at the forefoot level. During this study the medical history was obtained, the elasticity type of the feet was defined and the degree of motion of the medial metatarsal-cuneiform joint was evaluated. Forefoot elasticity was identified by bringing together the heads I and V metatarsal bones with fingers. If convergence occurred with little resistance, those feet were called hyperelastic. The convergence of the heads I and V metatarsal bones of the foot with an average type of elasticity occurred with resistance. It was impossible to converge the heads of I and V metatarsal bones. Due to the results of weight-bearing and non-weight bearing X-ray, analysis of the main radiographic angles of the foot was performed: between I and V metatarsal bones, between the first and second metatarsal bones and between the first metatarsal bone and proximal phalanx of the great toe. Calculation formula of the forefoot flatness index, showing the average ratios of basic radiographic angles of the foot on the x-ray images (weight-bearing and non-weight bearing) was created. An assessment of total joint hypermobility using Beighton scale and evaluation of first ray deformity using DuPont scale were performed. Statistical analysis of obtained data was performed, as a result of which significantly strong correlation between total joint hypermobility, forefoot elasticity and valgus deviation of the great toe were revealed. Results. 11% of the feet were hyperelastic. Calculation of the index of forefoot flatness showed that forefoot flatness wasn’t significant for a rigid foot - 5.6 %, for the feet with an average degree of mobility it was 6.0% and it was expressed for hypemobile feet - 12.3 %. Strong correlation relation between the forefeet mobility degree, the number of points on a DuPont scale and the degree of sagittal mobility of the medial metatarsal-cuneiform joint were revealed. Conclusion. Our study demonstrates that generalized joint hypermobility, horizontal and sagittal first ray mobility and forefoot deformities are directly proportional.

On orthogonal ray trees

An orthogonal ray graph is an intersection graph of horizontal rays (closed half-lines) and vertical rays in the plane, which is introduced in connection with the defect-tolerant design of nano-circuits. An orthogonal ray graph is a 3-directional orthogonal ray graph if every vertical ray has the same direction. A 3-directional orthogonal ray graph is a 2-directional orthogonal ray graph if every horizontal ray has the same direction. The characterizations and the complexity of the recognition problem have been open for orthogonal ray graphs and 3-directional orthogonal ray graphs, while various characterizations with a quadratic-time recognition algorithm have been known for 2-directional orthogonal ray graphs. In this paper, we show several characterizations with a linear-time recognition algorithm for orthogonal ray trees by using the 2-directional orthogonal ray trees. We also show that a tree is a 3-directional orthogonal ray graph if and only if it is a 2-directional orthogonal ray graph. Moreover, we show some necessary conditions for orthogonal ray graphs and 3-directional orthogonal ray graphs.

Normal Mode Analysis of Three-Dimensional Propagation Over a Small-Slope Cosine Shaped Hill

Three-dimensional propagation over an infinitely long cosine shaped hill is examined using an approximate normal mode/parabolic equation hybrid model that includes mode coupling in the out-going direction. The slope of the hill is relatively shallow, but it is significant enough to produce both mode-coupling and horizontal refraction effects. In the first part of the paper, the modeling approach is described, and the solution is compared to results obtained with a finite element method to evaluate the accuracy of the solution in light of assumptions made in formulating the model. Then the calculated transmission loss is interpreted in terms of a modal decomposition of the field, and the solution from the hybrid model is compared to adiabatic and N × 2D solutions to assess the relative importance of horizontal refraction and mode-coupling effects. An analysis using a horizontal ray trace is presented to explain differences in the modal interference pattern observed between the 3D and N × 2D solutions. The detailed discussion provides a thorough explanation of the observed 3D propagation effects and demonstrates the usefulness of the approximate normal mode/parabolic equation hybrid model as a tool to understand measured transmission loss in complex environments.

Coupled mode analysis of three-dimensional propagation over a cosine shaped hill

Three-dimensional propagation over an infinitely long cosine shaped hill is examined using an approximate normal mode/parabolic equation hybrid model that includes mode coupling in the out-going direction. The slope of the hill is relatively shallow, but it is significant enough to produce both mode-coupling and horizontal refraction effects. The modeling approach is described and the solution is compared to results obtained with a finite element method to evaluate the accuracy of the solution in light of assumptions made in formulating the model. Then, the calculated transmission loss is interpreted in terms of a modal decomposition of the field, and the solution from the hybrid model is compared to adiabatic and Nx2D solutions to assess the relative importance of horizontal refraction and mode-coupling effects. An analysis using a horizontal ray trace is presented to explain differences in the modal interference pattern observed between the 3D and Nx2D solutions. The detailed discussion provides a thoro...

Phloem as capacitor: radial transfer of water into xylem of tree stems occurs via symplastic transport in ray parenchyma.

The transfer of water from phloem into xylem is thought to mitigate increasing hydraulic tension in the vascular system of trees during the diel cycle of transpiration. Although a putative plant function, to date there is no direct evidence of such water transfer or the contributing pathways. Here, we trace the radial flow of water from the phloem into the xylem and investigate its diel variation. Introducing a fluorescent dye (0.1% [w/w] fluorescein) into the phloem water of the tree species Eucalyptus saligna allowed localization of the dye in phloem and xylem tissues using confocal laser scanning microscopy. Our results show that the majority of water transferred between the two tissues is facilitated via the symplast of horizontal ray parenchyma cells. The method also permitted assessment of the radial transfer of water during the diel cycle, where changes in water potential gradients between phloem and xylem determine the extent and direction of radial transfer. When injected during the morning, when xylem water potential rapidly declined, fluorescein was translocated, on average, farther into mature xylem (447 ± 188 µm) compared with nighttime, when xylem water potential was close to zero (155 ± 42 µm). These findings provide empirical evidence to support theoretical predictions of the role of phloem-xylem water transfer in the hydraulic functioning of plants. This method enables investigation of the role of phloem tissue as a dynamic capacitor for water storage and transfer and its contribution toward the maintenance of the functional integrity of xylem in trees.

Horizontal cosmic ray muon radiography for imaging nuclear threats

Muon tomography is a technique that uses information contained in the Coulomb scattering of cosmic ray muons to generate three dimension images of volumes between tracking detectors. Advantages of this technique are the muons ability to penetrate significant overburden and the absence of any additional dose beyond the natural cosmic ray flux. Disadvantages include the long exposure times and limited resolution because of the low flux. Here we compare the times needed to image objects using both vertically and horizontally mounted tracking detectors and we develop a predictive model for other geometries.

Dominating Sets and Induced Matchings in Orthogonal Ray Graphs

SUMMARY An orthogonal ray graph is an intersection graph of horizontal and vertical rays (closed half-lines) in the plane. Such a graph is 3-directional if every vertical ray has the same direction, and 2-directional if every vertical ray has the same direction and every horizontal ray has the same direction. We derive some structural properties of orthogonal ray graphs, and based on these properties, we introduce polynomial-time algorithms that solve the dominating set problem, the induced matching problem, and the strong edge coloring problem for these graphs. We show that for 2-directional orthogonal ray graphs, the dominating set problem can be solved in O(n 2 log 5 n) time, the weighted dominating set problem can be solved in O(n4 logn) time, and the number of dominating sets of a fixed size can be computed in O(n 6 logn) time, where n is the number of vertices in the graph. We also show that for 2-directional orthogonal ray graphs, the weighted induced matching problem and the strong edge coloring problem can be solved in O(n 2 + mlogn) time, where m is the number of edges in the graph. Moreover, we show that for 3-directional orthogonal ray graphs, the induced matching problem can be solved in O(m 2 ) time, the weighted induced matching problem can be solved in O(m 4 ) time, and the strong edge coloring problem can be solved in O(m 3 ) time. We finally show that the weighted induced matching problem can be solved in O(m 6 ) time for orthogonal ray graphs.

Propagation of broad-band signals in shallow water in the presence of horizontal stratification

Horizontal stratification in shelf zone of the ocean is provided by existence of coastal wedge, temperature fronts, nonlinear internal waves, slopes, and canyons, where typical scales are up to tenths of kilometer in range and up to tenths minutes in time, for some perturbations spatial scales are essentially different in different directions in horizontal plane. In this case, there is remarkable horizontal refraction in sound propagation and frequency dependence of horizontal ray trajectories. It means that Fourier components of wideband signal propagate along different paths joining source and receiver in the horizontal plane. Distribution of spectral components in horizontal plane has crescent-like shape and restricted by rays, corresponding to boundary frequencies in spectrum. Propagating wide-band signal has additional spectral distortion as a result of different phase shift for spectral components, propagating along different paths. Also there is difference in directions of wave vectors for difference spectral components (tangents to horizontal rays), leading to phenomena similar to spatial dispersion: different directions of phase and group velocities, compression and decompression of pulses, additional time delay of signal, etc. Mentioned phenomena are considered for models of coastal wedge and temperature fronts. Analytical estimations are presented, as well as results of numerical modeling.

Space-time sound field interference in the horizontal plane in a coastal slope region

The nonstationary interference structure formed in the horizontal plane in the field of a point source in a coastal slope region is analyzed on the basis of the space-time horizontal ray concept. For a model that includes the typical bathymetry and sound velocity profile, the space, time, and frequency dependences of the sound field are considered for different waveguide modes. The characteristic scales of the field variability in space and time are estimated. The frequency-time diagram is analyzed for the region of the interference of direct and reflected waves. The variability of the field interference structure in the presence of mesoscale perturbations is considered.

Refraction of horizontal rays and vertical modes from receding solitary internal wave front in shallow water

Previously, it was shown that on the approach of an internal wave to an acoustic source-receiver track in shallow water, interference between a direct and a horizontally refracted acoustic path can occur (J. Acoust. Soc. Am. 129(4), EL141, 2011). This phenomenon that is dependent on the angular geometry between the solitary internal wave (IW) front and the acoustic track is similar to the well known Lloyd mirror interference phenomenon in optics. In particular, for a specific time during the SW06 experiment, it was shown that the refracted pulse propagating along horizontal ray, corresponding to the fourth vertical mode arrives with temporal delay relative to the direct horizontal ray. In this paper, we show this phenomenon occurring on the back front of the solitary IW. On the receding front, the forth mode of the refracted signal occurs with an increasing delay in the modal arrival time as the IW leaves the acoustic track. This separation between the direct and the refracted path continues while it gets larger until the IW is far enough from the track for refraction not to occur. A theoretical description of this phenomenon in support of the experimental observation is also presented. [Work supported by ONR.]

PROCESSING AN OFFLINE INSERTION-QUERY SEQUENCE WITH APPLICATIONS

In this paper, we present techniques and algorithms for processing an offline sequence of update and query operations and for related problems. The update can be either all insertions or all deletions. The types of query include min-gap, max-gap, predecessor, and successor. Most problems we consider are solved optimally in linear time by our algorithms, which are based on new geometric modeling and interesting techniques. We also discuss some applications to which our algorithms and techniques can be applied to yield efficient solutions. These applications include an offline horizontal ray shooting problem and a shortest arc covering problem on a circle.

Exploring an under‐ice ocean cavity with sound.

Sensible predictions of the future rise in sea level require an understanding of the melting processes underneath the floating ice sheets of Antarctica and Greenland. Acoustic transmissions into the ocean caverns underlying the ice sheets could provide time series of temperatures and currents to augment intermittent measurements by instruments lowered through the ice and carried on autonomous underwater vehicles. The wedge of diminishing height formed between the underside of the ice and the shoreward sloping seafloor will horizontally refract sound transmitted into the ocean cavern by a source seaward of the ice edge. Incoming rays come to a coastal turning point near the grounding line of the ice sheet before returning seaward. A highly idealized model of vertical mode structure and horizontal ray structure provides estimates of the transmission paths in the wedge. In the ideal case, source‐receiver separations of order 100 km for the broad Antarctic ice sheets are expected to provide good coastal returns, but separations of order 20 km for the narrow Greenland floating ice tongues are expected to result in severe reflection losses at the coastal turning points. Receivers lowered through the ice would provide valuable additional information. Further calculations using realistic propagation models are essential.

Theory of the Excitation and Propagation of Lamb's Atmospheric Edge Mode from Nuclear Explosions

Summary A relatively simple theoretical model of near-surface pressure pulse propagation from nuclear explosions is developed from the hypothesis that the early portion of the pulse travels in the real atmosphere's counterpart of Lamb's edge mode. Various concepts of geometrical acoustics are used in the construction of the model. The pulse travels along horizontal ray paths which may be refracted by horizontal variations in the height-averaged effective sound speed and wind velocity. The dispersion of the pulse as it propagates along such paths is governed by a one- dimensional wave equation similar to that derived by Korteweg & de Vries in 1895. Coefficients are found by comparison with the dispersion relation derived by Garrett in 1969 as an expansion in terms of a parameter e describing deviations of the atmospheric profile from isothermal. The method of incorporation of terms governing accumulative far-field non-linear effects is indicated. Height variations in propagating variables are approximated to zeroth order in δ. Variations along horizontal ray paths are governed by the principle of conservation of modal wave action. The excitation of the edge mode is found by matching the general form of the far-field quasi-geometrical solution to the near-field solution for a point energy source in an isothermal atmosphere. Explicit expressions are given for the far-field pressure disturbance. Computations agree favourably with those based on a multimode theory for the first few cycles of the waveform. The edge mode theory leads to a number of implications, which may be compared with existing data. These include the prediction that the energy of the explosion yield may be estimated from a knowledge of the first peak-to-peak period and first peak-to- trough pressure amplitude in far-field records with very little information concerning atmospheric structure, and the prediction that anomalous azimuthal variations in waveform amplitudes may be caused by focusing or defocusing of horizontal ray paths for the edge mode.