Cutoff Depth Research Articles

Development of Low-Stress Double-Pass Filter Device for Methane and Ethane Flammable Gas Detection System

To meet the needs of industrial and environmental monitoring of methane and ethane flammable gases, a low-stress filter device for detecting methane and ethane simultaneously is developed based on the absorption spectra of methane and ethane and the thin-film design theory. In order to improve the sensitivity of the detection system and reduce the influence of environmental noise, the information of methane and ethane gas is extracted simultaneously by using a filter with double bandpass and wide cut-off in the middle-infrared and far-infrared bands. The transmittance of the filter is 91.3%, 93.1%, and 93.02% at the wavelengths of 3.31 μm, 6.71 μm, and 7.67 μm, respectively. The cut-off depth in the cut-off interval is above OD3, which meets the system’s requirements.

S664 Pathologic Evaluation to Determine Depth of Invasion Cutoff for Superficial Esophageal Submucosal Adenocarcinoma

S664 Pathologic Evaluation to Determine Depth of Invasion Cutoff for Superficial Esophageal Submucosal Adenocarcinoma

A Semi-Analytical Solution of Two-Dimensional Unsteady Groundwater Flow Outside a Long-Strip Excavation Pit with a Cut-Off Wall

In deep excavation engineering, the implementation of cut-off walls stands as a crucial measure to ensure structural support stability. However, the existing theories for dewatering design often overlook the variations in cut-off wall penetration depths, potentially compromising the efficacy of groundwater control strategies. Addressing this gap, this study conducts a comprehensive investigation into the dynamics of groundwater levels within confined aquifers during the dewatering process of strip excavation pits with cut-off walls. Central to this inquiry is the conceptualization of the entire excavation pit as a singular large-diameter well, with the open part beneath the cut-off wall in the confined aquifer serving as a constant-flux boundary. Employing an advanced analytical modeling approach, the study formulates a robust framework to describe the intricate interplay of unsteady groundwater flow phenomena. Leveraging the techniques of the Laplace and finite cosine transform methods, a semi-analytical solution is derived to elucidate groundwater drawdown patterns over time. The validation of the proposed solution against finite element method results underscores its fidelity and applicability. The parametric analysis reveals a dynamic evolution in drawdown characteristics within the confined aquifer, transitioning from initially cone-shaped distributions to more linear profiles that eventually stabilize with prolonged dewatering. This evolution is governed by the aquifer’s inherent anisotropy and the barrier effect exerted by the depth of cut-off wall penetration. The parametric research also underscores the critical role of lateral boundary distance in influencing groundwater drawdown patterns. The presented solutions can be used to identify optimal penetration depth ratios tailored to specific parameters, thereby offering insights for optimizing dewatering strategies for deep excavation groundwater control. Moreover, a case study was included in this study using the proposed analytical solution, and a comparison was made with field data to validate the practical applicability of the approach.

Deep crustal fluids and their relation to cutoff depths of crustal earthquakes in the North Ibaraki area of northeastern Japan inferred from reflected S-waves

Crustal fluids play an essential role in the activity of crustal earthquakes. The north Ibaraki area in northeastern Japan has shown intense crustal seismicity after the 2011 Tohoku-oki earthquake. In this area, it is discussed that crustal fluids are supplied from the deep part of the Earth's crust and contribute to the genesis of these crustal earthquakes. To investigate the distribution of crustal fluids in this area, we focused on reflected S-waves, which are highly sensitive to the presence of crustal fluids. We developed an approach based on the Markov chain Monte Carlo method to precisely and quantitatively estimate the location of the crustal reflector and its geometry. The obtained results showed that the crustal reflector was located at depths of 15–25 km and dipped shallowly to the northwest. The crustal reflector was positioned above the region characterized by low seismic wave velocity and electrical resistivity anomalies in the lower crust, suggesting that the crustal reflector is the uppermost boundary of a fluid-rich zone. The distribution of the fluid-rich zone closely corresponded to the cutoff depths of crustal earthquakes. This fluid-rich zone was likely the source of the fluid that enhanced seismicity in the shallow part of the crust in the target area. In contrast, the fluid-rich zone itself may have suppressed the genesis of crustal earthquakes. We hypothesized that hydrothermal fluids might affect the shallowing of these cutoff depths. If the hydrothermal fluid was contained in the fluid-rich zone, it could induce a shallow brittle-ductile transition by increasing the temperature of the surrounding rocks.

X-ray storage tracks characteristics for Ag-doped phosphate glass based on radio-photoluminescence

Ag-doped phosphate glass (Ag-PG) is an excellent X-ray image storage material applied for recording X-ray tracks. In this work, we used Geant4 software to simulate the energy deposition attenuation and 2D/3D storage tracks characteristics of Ag-PG. The influence of the secondary particles generated by the interaction between X-rays and Ag-PG was analyzed. The storage cutoff depth of Ag-PG was verified at the Shanghai Synchrotron Radiation Facility (SSRF). The results show that the optical transmittance is slightly decreased after X-ray irradiation. The cutoff depth is only 200 μm for complete absorption, when the X-ray energy is 5 keV. The deposited energy is attenuated by 19.8% at the depth of 900 μm, when the X-ray energy is 30 keV. The distribution of deposited energy is primarily influenced by the attenuation of secondary electrons generated by the interaction between X-rays and Ag-PG. Furthermore, the 2D/3D models show that the storage depth is not significantly affected by different doses at the same X-ray energy. The low diffusion of the tracks spread plays a crucial role in achieving high spatial resolution. The storage cutoff depth in Ag-PG is approximately 10 mm at 20 keV. This has been successfully verified by SSRF, and it holds great significance for high-resolution imaging and quantitative storage of X-ray images in Ag-PG.

Analysis of the Application of the Micrometric Substaging System to Predict Recurrence and Progression in a Cohort of Patients with pT1 High-Grade Non-Muscle Invasive Bladder Cancer.

The World Health Organization (WHO) classification system for bladder cancer (BC) advocates for the substaging of pT1 disease, which may improve the prediction of cancer recurrence and progression. This study aims to evaluate the application and prognostic significance of a micrometric substaging system, utilising a 1 mm cut-off depth of invasion in patients with pT1 BC. We retrospectively reviewed all patients diagnosed with pT1 High-Grade Non-Muscle Invasive Bladder Cancer (NMIBC) at our institution. Lamina propria infiltration was categorised using a 1 mm cut-off to differentiate between Focal (<1 mm) or Extended (≥1 mm) disease, dividing the patients into Focal and Extended groups. The study included 114 patients, with a median (Interquartile Range (IQR)) age of 78 (71-87) and a Charlson Comorbidity Index (CCI) of 6 (5-7). The median follow-up was 33 (20-53) months. Of these, 56 patients (49.0%) were classified as having focal invasive, while 58 (51.0%) had Extended invasion. Demographic and pathological characteristics were evenly distributed between the two groups without significant differences (p > 0.05). However, Extended disease was more prevalent at initial diagnosis (Odds Ratio (OR) 5.44, p = 0.003). Multivariate analysis identified a first diagnosis of BC, pathological Grade 3 (G3), presence of Carcinoma in situ (CIS) and residual tumour at second resection as independent predictors of Extended pT1. Recurrence rates, progression rates and cancer-specific mortality were 41.2%, 5.3% and 1.8%, respectively. There were no statistically significant differences between the Focal and Extended groups in 3-year recurrence-free (58.9% vs 63.8%, p = 0.654), progression-free (92.9% vs 96.5%, p = 0.270) and cancer-specific survival (100% vs 98.3%, p = 0.425) rates. In this retrospective, single-centre study, substaging by depth of invasion did not predict recurrence, progression or cancer-specific mortality in patients with pT1 NMIBC. The initial diagnosis of pT1 BC, presence of G3, CIS and residual tumour at the second resection were identified as independent predictors of Extended pT1.

The Correlation Between Depth of Invasion, and Degree of Differentiation with Cervical Lymph Node Metastasis in Oral Squamous Cell Carcinoma

Objective: To study the significance of Depth of invasion (DOI), and the degree of differentiation (DOD) as predictors of cervical nodalmetastasis in oral squamous cell carcinoma. To determine a cut-off depth beyond which there is a high risk of cervical metastasis. Todetermine whether the DOI can be is alone enough as predictor for lymphatic metastasis despite the DOD. Methods: Forty-eight patients with OSCC were included in the study 28 males and 20 females ranging between 25 to 80 years. Alltreated in Ghazi Al-Hariri hospital for surgical specialties in Baghdad Medical city between 2017 to 2019. Slides were examined afterimmunohistochemical staining. Depth of invasion was measured according to the criteria of AJCC, and the WHO system of grading was, all histopathological parameters were recorded after immunohistochemical staining. Results: The depth of invasion ranged between 2 and 13 mm with a mean of 6.58 mm and SD of ± 2.56 mm and it was found to be ahighly significant predictor for lymphatic metastasis (P-value = 0.001), the cut-off point with a significant risk of metastasis was 5 mm. Thedegree of differentiation was also a significant predictor for cervical metastasis (P-value = 0.024) with poorly differentiated SCC carrying the highest risk of cervical metastasis despite the depth of the tumor invasion. Conclusion: DOI and DOD were significant histological parameters that predict the behavior of the well and moderately differentiated oral squamous cell carcinoma and hence the management of the neck in OSCC. However, the depth of invasion was not significance in cases of poorly differentiated OSCC. Therefore, we recommend that elective neck dissection should be done in cases of poorly differentiated OSCC despite the DOI.

New Zealand Fault-Rupture Depth Model v.1.0: A Provisional Estimate of the Maximum Depth of Seismic Rupture on New Zealand’s Active Faults

ABSTRACT We summarize estimates of the maximum rupture depth on New Zealand’s active faults (“New Zealand Fault-Rupture Depth Model v.1.0”), as used in the New Zealand Community Fault Model v1.0 and as a constraint for the latest revision of the New Zealand National Seismic Hazard Model (NZ NSHM 2022). Rupture depth estimates are based on a combination of two separate model approaches (using different methods and datasets). The first approach uses regional seismicity distribution from a relocated earthquake catalog to calculate the 90% seismicity cutoff depth (D90), representing the seismogenic depth limit. This is multiplied by an overshoot factor representing the dynamic propagation of rupture into the conditional stability zone, and accounting for the difference between regional seismicity depths and the frictional properties of a mature fault zone to arrive at a seismic estimate of the maximum rupture depth. The second approach uses surface heat flow and rock type to compute depths that correspond to the thermal limits of frictional instabilities on seismogenic faults. To arrive at a thermally-based maximum rupture depth, these thermal limits are also multiplied by an overshoot factor. Both the models have depth cutoffs at the Moho and/or subducting slabs. Results indicate the maximum rupture depths between 8 (Taupō volcanic zone) and &amp;gt;30 km (e.g., southwest North Island), strongly correlated with regional thermal gradients. The depths derived from the two methods show broad agreement for most of the North Island and some differences in the South Island. A combined model using weighting based on relative uncertainties is derived and validated using constraints from hypocenter and slip model depths from recent well-instrumented earthquakes. We discuss modifications to the maximum rupture depths estimated here that were undertaken for application within the NZ NSHM 2022. Our research demonstrates the utility of combining seismicity cutoff and thermal stability estimates to assess the down-dip dimensions of future earthquake ruptures.

Evaluating the Impact of Inclined Cutoff-Wall to Control Seawater Intrusion in Heterogeneous Coastal Aquifers

Subsurface physical barriers have been effectively used to mitigate seawater intrusion (SWI). Traditionally, the primary emphasis in both numerical studies and practical implementations has been on vertical barriers. The current research aims to explore the dynamics of SWI under various cutoff-wall inclination angles and depths, as well as aquifer heterogeneity using both experimental and numerical simulations. The impact of aquifer characteristics was assessed by utilizing a low hydraulic conductivity (K) aquifer (case L), a high hydraulic conductivity aquifer (case H), and two stratified aquifers. The stratified aquifers were created by grouping different hydraulic conductivity layers into two cases: high K above low K (case H/L) and low K above high K (case L/H). The model simulations covered seven different cutoff-wall inclination angles: 45.0°, 63.4°, 76.0°, 90.0°, 104.0°, 116.6°, and 135.0°. The maximum repulsion ratio of SWI wedge length was observed at an inclination angle of 76.0° for cutoff-wall depth ratios up to 0.623. However, as the depth ratio increased to 0.811, the maximum repulsion ratio shifted to an angle of 63.4° for all aquifers studied. At an inclined cutoff depth ratio of 0.811, the cutoff-wall inclination angle of 45.0° had the most significant impact on the saltwater wedge area. This results in SWI area reductions of 74.9%, 79.8%, 74.7%, and 62.6% for case L, case H, case H/L, and case L/H, respectively. This study provides practical insights into the prevention of SWI. Nevertheless, a thorough cost–benefit analysis is necessary to assess the feasibility of constructing inclined cutoff-walls.

Edge Thomson scattering diagnostic with compact polychromators on the HL-3 Tokamak

The edge Thomson scattering (ETS) diagnostic with compact polychromators on the HL-3 Tokamak was developed recently. The energy and repetition frequency of the Nd: YAG laser are 2.0 J and 30 Hz, respectively. The laser beam propagates vertically through the plasma region and the scattered light is observed horizontally. The projected scattering region at the plasma midplane is from 0.6 < r/a < 1.0. The 5-channel compact polychromator (width 432 mm, depth 472 mm and height 88 mm) is developed to measure the Thomson scattering spectra. Modular design in the power supply and the amplifier circuits simplifies the assembly and maintenance of the polychromator. By using the new narrow band filters with cut-off depth larger than OD 4, the stray light resulted from Nd: YAG laser has been suppressed by the polychromator. The signal to noise ratio (SNR) range of each channel is from 10 to 200 depending on plasma parameters. The designed electron temperature measurement range is from 5 to 1000 eV and electron density measurement range is from 5 × 1018 to 1 × 1020 m-3. New measurement results of electron temperature by ETS are compared with that from the electron cyclotron emission (ECE) radiometer. The time evolution of ETS and ECE matches with each other in different plasma discharges. Combined with the data from the core Thomson scattering diagnostic system, the plasma electron temperature profile on the HL-3 tokamak is presented for the first time.

Highlighting the Advantages of Operating NMC811 Cells to Voltages below 4.20 V Compared to NMC Grades with Lower Ni Content

Ni-rich Li-ion cells suffer from severe capacity fade at high states of charge (SOC) due to oxygen release and/or lattice volume collapse. We share long-term cycling results (12000 h) at 40 °C for NMC811, NMC532, and NMC640 cells cycled with different upper cut-off voltages (UCV), C-rates, and depths of discharge (DOD). We show that cycling to a greater UCV results in more capacity loss and resistance growth as expected. However, NMC811 suffered from 5–10 times greater resistance growth at 4.20 V compared to 4.06 V, while the resistance for NMC532 and NMC640 cycled to 4.30 V was roughly twice that of the 4.10 V UCV cells. This highlights a challenging problem with Ni-rich materials that can be mitigated if the UCV is limited to avoid NMC811 volume change. Finally, we used competitive graphite materials reported in previous work to examine the impact of UCV on the rate of SEI growth in NMC811 cells, which was found to increase with temperature and UCV, particularly at 4.08 V UCV. We hope this brief report will highlight the importance of lifetime energy output, rather than initial energy density, and encourage battery users to limit the UCV of Ni-rich cells when possible.

Properties of the Petrinja (Croatia) earthquake sequence of 2020–2021 – Results of seismological research for the first six months of activity

We present locations of almost 14,000 events from the first six months of the Petrinja (Croatia) earthquakes sequence (mainshock 29 December 2020, Mw 6.4). The catalogue is estimated complete for ML ≥ 1.20. Initially sparse local seismograph network was densified a week after the mainshock, which reduced uncertainties of focal locations by about 75%. Source-specific station corrections were used in an iterative location scheme. The hypocentres were located with 30 different sets of velocity models and program control parameters in order to gain insight into the epistemic uncertainty of each earthquake location. The bulk of epicentres are located close to, and to the SE of the causative, dextral strike-slip Petrinja fault, but considerable activity has been triggered on smaller faults, up to 25 km away. About a half of the 78 first-motion polarity focal mechanism solutions (FMS) from the full first year of activity were found to have mechanisms similar to the foreshock, the mainshock and the largest of aftershocks, while the rest indicated almost pure reverse faulting. Strike-slip mechanisms occurred more often close to the main fault. The P-axes of FMS for aftershocks were found to be on the average rotated by 16° clockwise with respect to the P-axis of the mainshock, regardless of the style of faulting. The spatial distribution of aftershocks coincides very well with the areas of positive Coulomb stress change caused by the mainshock rupture. The inferred cut-off seismogenic depth in the area (7–10 km), estimated on the basis of published values of the geothermal gradient and the assumption of predominantly granitic upper crust, is considerably shallower than the depth of the deepest reliably located aftershocks (16–18 km). This fact may be explained by considering ophiolite-dominated crust, and by increased strain rate during the sequence, which raises the ability of crustal rocks for brittle failure.

Constraining the geotherm beneath the Japanese islands from Curie point depth analysis and comparison with seismicity and drillhole data in the Kakkonda geothermal field

This paper shows results of Curie point depth (CPD) analysis of the Japanese Islands using magnetic data. The analysis method is Bouligand et al. (2009) based on fractal theory. This analysis result was combined with the cutoff depth of ordinary earthquakes, low frequency earthquakes and drillhole data. CPD by magnetic data (Dcmag) performed in the case of 50 km window size ranges 6–9 km deep in volcanic areas and is deeper than 9 km in non-volcanic areas. The results are concordant with the previous study by Okubo et al. (1989). Cutoff depths calculated by JMA unified catalog are 10 km or shallower in the volcanic area, deeper than 20 km in the forearc side and concordant with Dcmags. Dcmags across the Kakkonda GP gradually become shallower from 6.8 km west Akita-Komagatake toward to 4.6 km near Iwate volcano. The depth-to-temperature curves from drillhole database around the Kakkonda GP show that thermal gradients between Iwate volcano and the Kakkonda GP range 0.157 - 0.222 K/m. Assuming that these thermal gradients continue from the bottom of hole to the deeper part, the depths reaching 580 °C (Dchole) are determined. Dchole is concordant with Dcmag in the west side of the Kakkonda GP and much shallower than Dcmag in the east side. This suggests that Dcmags may miss to delineate a local high temperature area smaller than 50 km square in the east because of the average effect of CPD analysis. Dchole is shallower than 3 km west Iwate volcano and deepens at about 5 km west the Kakkonda GP. Combining the low frequency earthquakes data from the JMA unified earthquake catalog and the drillhole data of the Kakkonda geothermal field, we find the Curie point depths are consistent with those data.

Present-day activity and seismic potential of the north Qinling fault, southern ordos block, central China, as revealed from GPS data and seismicity

The North Qinling Fault, located at the boundary of the North China Block and the South China Block, represents an important tectonic structure between the Weihe Basin and the Qinling Mountains, and controls the subsidence and expansion of the Weihe Basin. This fault has been highly active and has caused strong earthquakes since the Holocene and in a pre-seismic stage currently, as indicated by the many paleoearthquake traces found along it. To determine the present-day activity and seismic potential of the North Qinling Fault, by inverting GPS data, we produced fault locking depth, slip rate, and regional strain fields maps; moreover, based on seismicity, we produced a seismic b-value map. Combining this information with modern seismicity, we were able to comprehensively analyze the seismic potential of different fault segments. Our inversion of GPS data showed that the slip rate of the western segment of the fault (Qingjiangkou–Xitangyu) and the correspondent locking depth are 1.33 mm/a and 13.54 km, respectively, while the slip rate of the middle segment (Xitangyu–Fengyukou) and the correspondent locking depth are 0.45 mm/a and 8.58 km, respectively; finally, the slip rate of the eastern segment (Xitangyu–Daiyu) and the correspondent locking depth are 0.36 mm/a and 21.46 km, respectively. The locking depths of the western and middle segments of the fault are shallower than 90% of the seismic cutoff depth, while the locking depth of the eastern segment of the fault is similar to 90% of the seismic cutoff depth, indicating that “deep creep” occurs in the western and middle segments, while the eastern segment is locked. Modern small earthquakes have involved the western and middle segments of the fault, while the eastern segment has acted as a seismic gap with weak seismicity, characterized by a higher shear strain value and a lower b-value. These characteristics reflect the relationship between the locking depth and seismicity distribution. The results of our comprehensive analysis, combined with field geological surveys, show that the eastern segment of the North Qinling Fault has a strong seismic potential and is presently locked.

Satellite-derived bathymetry online - Validation study, upscaling SDB, SDB potential

Satellite-Derived Bathymetry (SDB) methods have found their way into the hydrographers’ toolbox and are part of integrated survey concepts, nautical charts and support global and European programs such as Seabed2030 or EMODnet Bathymetry. The concept of the ‘physics-based’ SDB describes the calculation of bathymetry by modelling the sunlight path from the sun to the seafloor to the satellite sensor. It is a highly sophisticated model which enables the calculation of shallow water depth in the absence of any other survey or ground-truth data. Thus, bathymetric data can also be retrieved for remote and inaccessible areas - in contrast to empirical SDB approaches. Key questions which arise for SDB results are vertical accuracy, potential and feasibility for different sites and the methods to upscale SDB solutions. These questions are addressed in the current European innovation project 4S. Within the project SDB-Online was developed, a fully physics-based SDB concept which is installed in a cloud and accessible via a web user interface. The backend is parallelised and can be accessed via application programming interface (API) which allows a fully scalable and automatic SDB processing. In this study SDB-Online results are validated at ten sites, ranging from the higher latitudes of Canada to turbid UK waters to the Caribbean. Furthermore, a relationship between the Secchi Disc Depth and the cutoff depth of the SDB results is established and a global map of water-clarity potential of the SDB solution is presented.

Analysis of seepage control system improvement in an earthen dam

This paper concerns the adequacy of utilising a chimney drain, horizontal filter and cutoff wall in reducing seepage through an earthen dam. To this end, anti-seepage systems comprising a chimney drain, a horizontal filter and a cutoff wall were investigated. Variations of lengths, angles and locations of these features were studied. The amount of seepage was determined using SEEP/W software. The results indicated that by expanding the vertical chimney drain and the horizontal filter from the embankment toe to half or three-quarters of the downstream slope, the seepage flow from the dam body and its foundation will decrease. On the contrary, when the horizontal filter's length is extended to more than three-quarters of the dam's downstream slope, the amount of seepage flow that may pass through the dam's cross-section rapidly increases. Additionally, it was observed that seepage from the earthen dam and its foundation reduced by increasing the cutoff depth. Finally, with respect to the minimum factor of safety for the downstream slope, obtained using SLOPE/W software, a suitable model for seepage control within the body and foundation of the dam was found to be the hybrid model introduced at the end of this study.

Prediction of the high-cost normalised discounted cumulative gain (nDCG) measure in information retrieval evaluation

Introduction. Information retrieval systems are vital to meeting daily information needs of users. The effectiveness of these systems has often been evaluated using the test collections approach, despite the high evaluation costs of this approach. Recent methods have been proposed that reduce evaluation costs through the prediction of information retrieval performance measures at the higher cut-off depths using other measures computed at the lower cut-off depths. The purpose of this paper is to propose two methods that addresses the challenge of accurately predicting the normalised discounted cumulative gain (nDCG) measure. Method. Data from selected test collections of the Text REtrieval Conference was used. The proposed methods employ the gradient boosting and linear regression models trained with topic scores of measures partitioned by TREC Tracks. Analysis. To evaluate the proposed methods, the coefficient of determination, Kendall's tau and Spearman correlations were used. Results. The proposed methods provide better predictions of the nDCG measure at the higher cut-off depths while using other measures computed at the lower cut-off depths. Conclusions. These proposed methods have shown improvement in the predictions of the nDCG measure while reducing the evaluation costs.

Correlation and prediction of high-cost information retrieval evaluation metrics using deep learning

Introduction. To reduce cost of the evaluation of information retrieval systems, this study proposes a method that employs deep learning to predict the precision evaluation metric. It also aims to show why some of existing evaluation metrics correlate with each other while considering the varying distributions of relevance assessments. It aims to ensure reproducibility of all the presented experiments. Method. Using data from several test collections of the Text REetrieval Conference (TREC) we show why some evaluation metrics correlate with each other, through mathematical intuitions. In addition, regression models were used to investigate how the predictions of the evaluation metrics are affected by queries or topics with variations of relevance assessments. Lastly, the proposed prediction method employs deep learning. Analysis. We use coefficient of determination, Kendall's tau, Spearman and Pearson correlations. Results. This study showed that the proposed method performed better predictions than other recently proposed methods in retrieval research. It also showed why the correlation exists between precision and rank biased precision metrics, and why recall and average precision metrics have reduced correlation when the cut-off depth increases. Conclusions. The proposed method and the justifications for the correlations between some pairs of retrieval metrics will be valuable to researchers for the predictions of the evaluation metrics of information retrieval systems.

Horizontal refraction and diffraction of underwater sound around an island.

The three-dimensional (3D) propagation effects of horizontal refraction and diffraction were measured on a tetrahedral hydrophone array deployed near the coast of Block Island, RI. Linear frequency modulated chirp signals, centered at 1 kHz with a 400 Hz bandwidth, were transmitted from a ship moving out of the acoustic shadow zone blocked by the island from the perspective of the hydrophone array. The observed shadow zone boundary was consistent with the prediction made by a 3D sound propagation model incorporating high-resolution bathymetry and realistic sound speed obtained from a data-assimilated regional ocean model. The 3D modal ray calculation provided additional insight into the frequency dependence of the signal spreading. This analysis found that the modes at higher frequencies can propagate closer to the coast of the island with shallower modal cutoff depths, where the sound energy penetrates the sloping seafloor at supercritical incidence. The evidence of horizontal caustics of the sound was shown in the parabolic equation and modal ray models by comparing to the arrival pattern observed in the data. The arrival angle measurements on the tetrahedral array show the complex propagation patterns, including the diffracted energy in the island shadow and acoustic energy refracted away from the island.

The Improved Catheterization Is Associated With the Deeper Radial Arteries in Ultrasound-Guided Dynamic Needle Tip Positioning Technique.

ObjectiveThis study aimed to determine the associations between the first-attempt success and arterial depth in ultrasound-guided radial artery catheterization (RAC) with dynamic needle tip positioning (DNTP) technique. This study also aimed to further explore the cut-off depth correlated to improved first-attempt success catheterization in less time.MethodsThe cases undertaken by RAC within the DNTP technique between March 2019 and July 2020 were extracted from our institutional cohort database. Relevant variables were collected, including patients' demographics and catheterized information. Univariable and multivariable logistic regression analyses were performed to determine the association. The receiver operating characteristic (ROC) curve and the Youden index were used to explore the cut-off values of the arterial depth. Categorized cases according to the cut-off values, the Kaplan-Meier analysis, and the log-rank test were used to determine the difference of first-attempt success with limited catheterized time between groups.ResultsIn this study, 119 patients were enrolled and 98 achieved first-attempt success. The first-attempt success catheterization was observed to be correlated to arterial depth (p < 0.01, odds ratio 6.47). An optimal cut-off depth of 2.25 mm was found using the Youden index (0.53) by ROC curve (area under curve 0.77). Arterial depth of more than 2.25 mm was correlated to improved first-attempt success catheterization in less time (log-rank p < 0.01).ConclusionTo achieve first-attempt success catheterization using the DNTP technique, an arterial depth of more than 2.25 mm was associated with less catheterized time.