Reference Location Research Articles

Relative pose estimation from panoramic images using a hybrid neural network architecture

Camera-based relative pose estimation (RPE) localizes a mobile robot given a view at the current position and an image at a reference location. Matching the landmarks between views is critical to localization quality. Common challenges are appearance changes, for example due to differing illumination. Indirect RPE methods extract high-level features that provide invariance against appearance changes but neglect the remaining image data. This can lead to poor pose estimates in scenes with little detail. Direct RPE methods mitigate this issue by operating on the pixel level with only moderate preprocessing, but invariances have to be achieved by different means. We propose to attain illumination invariance for the direct RPE algorithm MinWarping by integrating it with a convolutional neural network for image preprocessing, creating a hybrid architecture. We optimize network parameters using a metric on RPE quality, backpropagating through MinWarping and the network. We focus on planar movement, panoramic images, and indoor scenes with varying illumination conditions; a novel dataset for this setup is recorded and used for analysis. Our method compares favourably against the previous best preprocessing method for MinWarping, edge filtering, and against a modern deep-learning-based indirect RPE pipeline. Analysis of the trained hybrid architecture indicates that neglecting landmarks in a direct RPE framework can improve estimation quality in scenes with occlusion and few details.

Spatial patterns of high-risk biomechanical metrics in plaques with abnormal vs. normal physiological flow indices

BackgroundPlaques associated with abnormally low physiological flow reserve indices are appropriate for percutaneous coronary intervention (PCI). However, recent trials demonstrate that PCI of ischemia-producing lesions does not reduce major adverse cardiac events (MACE). Low endothelial shear stress (ESS) or high ESS gradient (ESSG) are associated with MACE wherever they occur along the plaque. This study aims to determine the presence of high-risk ESS metrics in obstructive coronary plaques with high-risk (<0.80) vs. borderline-risk (0.80–0.89) vs. normal Instantaneous Wave-free Ratio (iFR) (>0.89). MethodsWe included 50 coronary arteries (50 patients) with variable iFR values who underwent coronary angiography and optical coherence tomography (OCT), followed by 3D reconstruction and computational fluid dynamics calculations of ESS/ESSG. The cohort was divided into 3 groups: iFR < 0.80, iFR 0.80–0.89, and iFR > 0.89. Spatial distribution of ESS metrics was reported along the course of each plaque, and high-risk ESS metrics and their location were compared among the 3 iFR subgroups. ResultsHigh-risk ESS features (Minimal ESS, Maximum ESSG) were similarly distributed along the course of the atherosclerotic plaque in the three iFR subgroups, both in absolute value and in location: Min ESS: 0.5 ± 0.3 vs. 0.4 ± 0.2 vs. 0.4 ± 0.2 Pa respectively (p = 0.60); Max ESSG any direction: 13.7 ± 9.4 vs. 10.4 ± 10.6 vs. 10.0 ± 7.8 Pa/mm respectively (p = 0.30). ESS metrics were spatially located up to ≥18 mm from the plaque minimal luminal area (MLA) in both directions. ConclusionHigh-risk ESS metrics are similarly observed in plaques with normal or abnormal iFR, both in absolute value and spatial location in reference to the MLA. Utilizing iFR to identify plaques likely to cause MACE would miss the majority of plaques mechanistically at high-risk to destabilize and cause future adverse cardiac events.

Fault Tolerant Metric Dimension of Arithmetic Graphs

For a graph G , two vertices x , y ∈ G are said to be resolved by a vertex s ∈ G , if d ( x | s ) ≠ d ( y | s ) . The minimum cardinality of such a resolving set R in G is called its metric dimension. A resolving set R is said to be fault-tolerant, if for every p ∈ R , R − p preserves the property of being a resolving set. A fault-tolerant metric dimension of G is a minimal possible order fault-tolerant resolving set. A wide variety of situations, in which connection, distance, and connectivity are important aspects, call for the utilisation of metric dimension. The structure and dynamics of complex networks, as well as difficulties connected to robotics network design, navigation, optimisation, and facility positioning, are easier to comprehend as a result of this. As a result of the relevant concept of metric dimension, robots are able to optimise their methods of localization and navigation by making use of a limited number of reference locations. As a consequence of this, numerous applications of robotics, including collaborative robotics, autonomous navigation, and environment mapping, have become more precise, efficient, and resilient. The arithmetic graph A l is defined as the graph with its vertex set as the set of all divisors of l , where l is a composite number and l = p γ 1 1 p η 2 2 , … , p n n , where p n ≥ 2 and the p i ’s are distinct primes. Two distinct divisors x , y of l are said to have the same parity if they have the same prime factors (i.e., x = p 1 p 2 and y = p 2 1 p 3 2 have the same parity). Further, two distinct vertices x , y ∈ A l are adjacent if and only if they have different parity and gcd ( x , y ) = p i (greatest common divisor) for some i ∈ { 1 , 2 , … , t } . This article is dedicated to the investigation of the arithmetic graph of a composite number l , which will be referred to throughout the text as A l . In this study, we compute the fault-tolerant resolving set and the fault-tolerant metric dimension of the arithmetic graph A l , where l is a composite number.

Tracking mercury sources in the Wabigoon River: Use of stable mercury isotopes in bioindicator organisms

Mercury concentrations remain elevated in sediments and biota of the Wabigoon River downstream from Dryden, Ontario, the home of a former chlor-alkali plant. Understanding the current extent and severity of mercury contamination downstream of this industrial legacy site is of great importance in managing the mercury contamination within the traditional territory of Asubpeeschoseewagong Anishinabek (Grassy Narrows First Nation), located downstream of Dryden. The objective of this study was to use mercury stable isotope ratio analysis to distinguish between legacy mercury from the former chlor-alkali plant and mercury from geogenic sources. Mercury concentrations in surface sediments and biota downstream of the historical source of mercury discharge are elevated relative to the chosen reference location, Wabigoon Lake (WL). Mean sediment mercury levels were as high as 3.27 μg/g at the hydroelectric dam location compared to 0.05–0.10 μg/g at Wabigoon Lake sediments. Isotope ratios in aquatic biota and sediments collected from within the system were distinct from Wabigoon Lake, indicating that anthropogenic mercury contamination is distinguishable from geogenic mercury. Average δ202Hg values of −2.46 ± 0.41 observed in sediments of WL were consistently more negative compared to downstream values, which varied from −1.34 to 0.30 ‰. Young-of-the-year Yellow Perch and Hexagenia were found to have significantly more positive δ202Hg values downstream from Wabigoon Lake.

Novel Use of Concentrated Solar Thermal Energy for Producing Highly Thermal Activated Materials for CCUS via Mineral Carbonation of Mine Waste

An assessment of the levelised cost and associated CO2-eq emissions for the thermal activation of serpentine mine tailings to be used as activated feedstock for CCUS processes via mineral carbonation, is reported here for the first time. Two main technological scenarios were assessed, based on either direct fuel sources heating (natural gas and hydrogen) or indirect, CST-based heating with a back-up burner and storage to provide continuous operations, for a 200 ton/hr of processed ore and a targeted roasting ore temperature of 700°C. For CST-based systems, 3 different solar input scales, namely 50, 150 and 450 MWth, were considered, and simulations performed over a year timeline with a 10 minutes time step, using Mt Keith Nickel mine in Western Australia as the reference location. The analysis highlighted that the proposed CST-hybrid plant layout can achieve similar cost to that of fuel-only cases with current Australian fuel prices for natural gas and hydrogen, with lower CO2-eq emissions, and a parity cost with fuel-only scenarios of some 16 USD/GJ. The proposed CST-hybrid plant layout was also identified as the potential, preferred route over direct CST routes to achieve 24/7 continuous heat supply while retaining fine tuning of activation temperature, given a very narrow temperature window of activation for the chosen mine tailings for mineral carbonation processes.

Quantitative Analysis of Iron Activity in Agricultural Soils Using X-ray Fluorescence Spectrometry: Comparative Study with an Undisturbed Reference Site in Niankhene, Senegal

An essential micronutrient for plant growth and development, iron (Fe) affects a number of physiological processes, including respiration and photosynthesis. This study compare the amounts of iron in agricultural zones and reference zones, describe the geographic distribution of iron, and assess its accessibility to cultures. The aim is to assess the deficiencies and excess soil disturbance in the Niankhène agricultural site while maintaining a stable site. Soil samples were taken at 0–20 cm and 20–40 cm depths from 47 agricultural stations and three reference points using X-ray fluorescence (XRF) spectroscopy. Significant variation in Fe concentrations was found by the research, with an average of roughly 3310.95 ppm and moderate variation between samples. An analysis conducted in comparison with reference locations revealed a widespread lack of Fe in the research area, with 85.71% of samples displaying depletion and only 14.29% displaying accumulation of Fe. This discrepancy emphasizes the necessity of focused soil management techniques to raise Niankhene&amp;apos;s agricultural output. The results highlight how crucial it is to use site-specific soil management strategies in order to overcome Fe deficits and raise crop yields. This research highlights the possibility for establishing targeted fertilization and corrective procedures to maximize Fe availability by utilizing XRF technology for reliable soil nutrient monitoring. The study&amp;apos;s findings offer insightful information for enhancing fertilization techniques and improving soil management techniques, which will support sustainable farming methods and increased crop yield in the area.

Technical note: assessing GPS sensor accuracy using real-time kinematic device for livestock tracking.

The technical aspects of global positioning system (GPS) sensors have been improved substantially over the years, making them valuable and popular tools for livestock tracking. Using GPS sensors allows producers and researchers to locate grazing livestock, monitor their behavior and distribution, and gather referencing information about the health status of the animals and pastures. However, interpreting the behavior of grazing livestock, such as cattle, from GPS data can be difficult due to positioning inaccuracies. Without knowing the positioning accuracy range of GPS sensors, achieving high-level confidence in determining grazing densities and identifying abnormal livestock movement patterns is challenging. In this study, the positioning accuracy of 3 different types of commercial GPS sensors was assessed using a survey-grade real-time kinematics (RTK) device. We outlined the procedures and essential equations and compared the recorded locations from the GPS sensors with reference locations collected from the RTK device. The results demonstrated statistically significant differences (P < 0.05) in positioning accuracy between different types of GPS sensors. The circular error probable (CEP) at 95% probability levels (CEP95) of the 3 sensors ranged from 2.46 to 11.06 m. This accuracy varied among individual sensors within the same brand and across different brands, which underscores the importance of evaluating the positioning accuracy of GPS sensors in livestock tracking. This study provides significant insights for animal scientists, ecologists, and livestock producers engaged in GPS sensor-related research and practices.

Prevalence and characteristics of and risk factors for impacted teeth with ankylosis and replacement resorption – a retrospective, 3D-radiographic assessment

BackgroundLarge variation in the prevalence of ankylosis and replacement resorption (ARR) is reported in the literature and most studies have relatively small patient numbers. The present retrospective study aimed to provide an overview on prevalence, location of, and associated risk factors with ARR based on a large sample of computed tomography (CT) / cone beam computed tomography (CBCT) scans of impacted teeth. The results should allow clinicians to better estimate the risk of ARR at impacted teeth.MethodsThe CT/CBCT scans of 5764 patients of a single center in Central Europe were screened with predefined eligibility criteria. The following parameters were recorded for the finally included population: gender, age, tooth type/position, number of impacted teeth per patient, and presence/absence of ARR. For teeth with ARR the tooth location in reference to the dental arch, tooth angulation, and part of the tooth affected by ARR were additionally registered.ResultsAltogether, 4142 patients with 7170 impacted teeth were included. ARR was diagnosed at 187 impacted teeth (2.6%) of 157 patients (3.7%); 58% of these patients were female and the number of teeth with ARR per patient ranged from 1 to 10. Depending on the tooth type the prevalence ranged from 0 (upper first premolars, lower central and lateral incisors) to 41.2% (upper first molars). ARR was detected at the crown (57.2%), root (32.1%), or at both (10.7%). After correcting for confounders, the odds for ARR significantly increased with higher age; further, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest. More specifically, for 20-year-old patients the risk for ARR at impacted incisors and first/second molars ranged from 7.7 to 10.8%, but it approximately tripled to 27.3–35.5% for 40-year-old patients. In addition, female patients had significantly less often ARR at the root, while with increasing age the root was significantly more often affected by ARR than the crown.ConclusionARR at impacted teeth is indeed a rare event, i.e., only 2.6% of 7170 impacted teeth were ankylosed with signs of replacement resorption. On the patient level, higher age significantly increased the odds for ARR and on the tooth level, incisors and first/second molars had the highest odds for ARR, while wisdom teeth had the lowest.

Interannual and spatial variations in acid-soluble trace elements in snow: comparison with the mineralogy of dusts from open pit bitumen mining

There is ongoing concern about trace element (TE) emissions to the global environment from the dusts generated by open pit mining of coal, iron ore, stone quarries, and aggregate extraction. However, the chemical composition and acid solubility of these dusts is highly variable. Here, TEs were determined in snow collected in 2016 and 2017 in the vicinity of open-pit bitumen mines in northern Alberta, Canada. Acid solubility was assessed quantitatively by comparing TE concentrations in leachates and acid digests. The mineralogical composition of the particles extracted from the snow was examined using SEM-EDS. The data is reproducible from one year to the next. TE concentrations were greater throughout the industrial zone compared to the reference location (UTK), with the midpoint between the two central upgraders being especially impacted. Regardless of their geochemical class (lithophile: Al, Be, Cs, La, Li, Sr, Th; chalcophile: As, Cd, Pb, Sb, Tl; or enriched in bitumen: Mo, Ni, V), all TEs showed strong, positive correlations with Y, a conservative element which serves as a surrogate for the abundance of mineral particles. The ratio V:Ni in the snow is less than the corresponding values for bitumen and petcoke, but similar to that of local road dust. The ratio La:Al in snow is elevated, relative to the earth's crust, suggesting an enrichment of heavy minerals monazite and zircon. The predominance of quartz and other stable silicates helps to explain the limited chemical solubility of the dusts, and predicts a low bioaccessibility of these TEs in the environment.

Angle Dependence of Electrode Lead-Related Artifacts in Single- and Dual-Energy Cardiac ECG-Gated CT Scanning-A Phantom Study.

Background: The electrodes of implantable cardiac devices (ICDs) may cause significant problems in cardiac computed tomography (CT) because they are a source of artifacts that obscure surrounding structures and possible pathology. There are a few million patients currently with ICDs, and some of these patients will require cardiac imaging due to coronary artery disease or problems with ICDs. Modern CT scanners can reduce some of the metal artifacts because of MAR software, but in some vendors, it does not work with ECG gating. Introduced in 2008, dual-energy CT scanners can generate virtual monoenergetic images (VMIs), which are much less susceptible to metal artifacts than standard CT images. Objective: This study aimed to evaluate if dual-energy CT can reduce metal artifacts caused by ICD leads by using VMIs. The second objective was to determine how the angle between the electrode and the plane of imaging affects the severity of the artifacts in three planes of imaging. Methods: A 3D-printed model was constructed to obtain a 0-90-degree field at 5-degree intervals between the electrode and each of the planes: axial, coronal, and sagittal. This electrode was scanned in dual-energy and single-energy protocols. VMIs with an energy of 40-140 keV with 10 keV intervals were reconstructed. The length of the two most extended artifacts originating from the tip of the electrode and 2 cm above it-at the point where the thick metallic defibrillating portion of the electrode begins-was measured. Results: For the sagittal plane, these observations were similar for both points of the ICDs that were used as the reference location. VMIs with an energy over 80 keV produce images with fewer artifacts than similar images obtained in the single-energy scanning mode. Conclusions: Virtual monoenergetic imaging techniques may reduce streak artifacts arising from ICD electrodes and improve the quality of the image. Increasing the angle of the electrode as well as the imaging plane can reduce artifacts. The angle between the electrode and the beam of X-rays can be increased by tilting the gantry of the scanner or lifting the upper body of the patient.

Response of hyporheic biofilms to temperature changes and dissolved organic carbon enrichment: a mesocosm study

PurposeHyporheic biofilms are the central site for biogeochemical cycling in streams and rivers. In view of global warming and increasing human pressures, this study aimed to compare the response of hyporheic biofilm biomass and activities from an unpolluted reference stream reach surrounded by forest with those from a stream reach exposed to agricultural and urban land use using a mesocosm experiment in which the water temperature and dissolved organic carbon (DOC) contents were manipulated.MethodsHyporheic sediments collected in the field from the two study reaches (i.e. reference and impacted) were incubated in the laboratory at two different temperatures (10 °C, 14 °C) and wetted with three types of synthetic water (control [C] – 0 mg L−1; low DOC – 5 mg L−1; high DOC – 30 mg L−1) for four weeks. The responses of the hyporheic biofilms were measured weekly using structural (total protein content [TPC] as a proxy for biofilm biomass) and functional measures (electron transport system activity [ETSA] and community-level physiological profiling [CLPP]).ResultsThe response of hyporheic biofilms to temperature changes and DOC enrichment was site-specific for all studied measures (TPC, ETSA and CLPP, including measured average well colour development [AWCD]). The addition of DOC to biofilms from the pristine stream reach significantly heightened the responses at 10 °C, a temperature within the normal environmental temperature ranges of the reference location, but not at 14 °C, which was here, a temperature outside normal environmental range. On the other hand, biofilms from the impacted stream reach exhibited increased responses following DOC enrichment under both temperature regimes, with a particularly pronounced response at 14 ºC, in this case, both experimental temperatures were within the normal environmental temperature ranges of the study locations.ConclusionHyporheic biofilms were shown to be, like benthic biofilms, sensitive to temperature changes and organic enrichment, but their response to temperature changes and enrichment caused by climate change and/or other anthropogenic pressures (i.e. point and non-point pollution, removal of the riparian zone, hydromorphological modifications, etc.) was not simply linear but site-specific. The intensity of the response, characterized by increased activity and biomass production, appears to be constrained within the temperature ranges prevalent in the environment from which the biofilms originate. These findings emphasize the importance of site-specific considerations in predicting the impacts of climate change and anthropogenic pressures on these critical components of river and stream ecosystems.

Emergency Response Person Localization and Vital Sign Estimation Using a Semi-Autonomous Robot Mounted SFCW Radar.

The large number and scale of natural and man-made disasters have led to an urgent demand for technologies that enhance the safety and efficiency of search and rescue teams. Semi-autonomous rescue robots are beneficial, especially when searching inaccessible terrains, or dangerous environments, such as collapsed infrastructures. For search and rescue missions in degraded visual conditions or non-line of sight scenarios, radar-based approaches may contribute to acquire valuable, and otherwise unavailable information. This article presents a complete signal processing chain for radar-based multi-person detection, 2D-MUSIC localization and breathing frequency estimation. The proposed method shows promising results on a challenging emergency response dataset that we collected using a semi-autonomous robot equipped with a commercially available through-wall radar system. The dataset is composed of 62 scenarios of various difficulty levels with up to five persons captured in different postures, angles and ranges including wooden and stone obstacles that block the radar line of sight. Ground truth data for reference locations, respiration, electrocardiogram, and acceleration signals are included.

The comparison and processing of Electromyography (EMG) signals under different actions

The experiment first investigates the working principle and the applications of Electromyography (EMG). Then, the effect of electrode location and electrode size on the EMG signal is explored by the raw data and theory. The reasons for choosing generic surface Ag/AgCl adhesive electrodes are also described. After obtaining the raw EMG signals, suitable data processing methods, such as Root Mean Square (RMS) and digital filtering are applied to generate signals that can drive the motor of a prosthetic arm. The results obtained by the two methods are also compared, where RMS can provide larger peak and mean values, and the digital filtering method can minimise the phase shift. Finally, the limitations of the EMG for prostheses are also analysed by three aspects: different flexion forces, individual finger motion and different reference locations.

Current status of reference location in the basic model for assessment of external radiation doses to the population living in radioactively contaminated areas after the Chernobyl accident

An open plot of virgin land is the reference location in the basic model used to date to estimate the effective dose of external exposure to the population living in a radioactively contaminated area. As our field observations in the Bryansk region of Russia have shown, at present it is very difficult to find truly reference plots of virgin land due to the fact that many virgin meadows were plowed or reclaimed for more than 30 years after the Chernobyl accident. Without special instrumental survey, such disturbed meadow areas can easily be confused with areas of virgin soil. Therefore, the situation with the use of open areas of virgin soil as the reference location has changed dramatically since the first years after the Chernobyl accident. It requires a change in the approach to choosing such a location for the model and/or some revision of the structure of the model itself. Firstly, we propose and justify the use of a permanently cultivated kitchengarden plot as the reference location. The second way to resolve the current difficult situation with the presence of a sufficient number of the virgin soil sites could be excluding the very concept of “reference location” from the model. In this case, when calculating the effective dose of external radiation, it is proposed to directly use the values of the gamma radiation dose rate in the air normalized to the 137Cs contamination density of soil. The values of the normalized dose rate should be experimentally determined in the required time period for each of the locations taken into account in the model.

Benefit of the nutritional and mineral composition of sea lettuce from a traditional salina: Implications for human consumption

The proximal composition and its seasonal variation of the green seaweed Ulva sp. harvested in a traditional saline (earthen ponds used for marine salt extraction) from Cadiz Bay (Southern Spain) was evaluated. Ulva sp. was also collected in a reference location within the Bay in order to compare and evaluate the effects of the particular characteristics of the saline in the composition of the macroalgae. Moisture, protein, lipid, ash, carbohydrate, fiber and macro- (Na, K, Ca, Mg), micro-mineral contents (Fe, Zn, Cu) and heavy metals (As, Cd, Co, Cr, Hg, Ni, Pb, Sn) of harvested biomass samples as well as environmental parameters of seawater (temperature, salinity, pH, DO, NH4+, NO3−, NO2− and PO43−) were measured. The results showed that Ulva sp. from the earthen ponds in the traditional salina was a better source of proteins, lipids, K and Mg, highlighting in summer with values of 27.54 % versus 6.11 %; 6.71 % versus 3.26 %; 26.60 mg g−1 versus 14.21 mg g−1 and 23.13 mg g−1 versus 17.79 mg g−1, respectively. It also had Na/K and Ca/Mg ratios of less than one, suggesting a healthy food source. Considering the Commission Recommendation (EU) 2018/464 as a working reference, Ulva sp. did not exceed the limit of toxic metals for human consumption.A season and site-season significant interaction on the composition of the seaweeds was observed. The proximal and mineral composition of Ulva sp. was influenced by the special features and environmental conditions of the earthen ponds. Hence, significant differences were observed in the macroalgae collected in the earthen ponds in summer and autumn, in contrast to the winter and spring samples, whose characteristics were similar to those from the inner bay. The closure of the lock-gates in summer to favor the production of salt significantly modified the environmental characteristics of the saline, affecting the physiological capacity of Ulva sp. to assimilate and storage nutrients, and therefore its tissue composition. As a consequence, the highest contents of lipid, ash, Ca, K, Mg and Fe were estimated in the macroalgae.

Source apportionment of polychlorinated biphenyls in the sediment of the Newtown Creek superfund site

Polychlorinated biphenyls (PCBs) are a primary contaminant of potential concern at the Newtown Creek superfund site. Measurements of PCBs in hundreds of samples of sediment (surface and cores) within Newtown Creek and at nearby reference locations were obtained from the Remedial Investigation (RI) databases. This data set was analyzed using Positive Matrix Factorization (PMF). A weight-of-evidence approach was used to attribute the PMF-generated fingerprints to sources. The PMF analysis generated eight factors (fingerprints or sources) that represent primary sources, such as Aroclors, as well as secondary sources, including the East River and Combined Sewer Outfalls (CSOs). In addition to the high-production volume Aroclors (1016/1242, 1248, 1254, and 1260), some less-widely used Aroclors (1232 and 1268) were found in Newtown Creek sediment. Aroclor 1268 is disproportionately abundant in the deepest sediments, while PCBs likely from CSOs are relatively more abundant in surface sediment.

Assessment of canalis sinuosus, rare anatomical structure using cone-beam computed tomography: A prospective study.

This prospective study was performed with cone-beam computed tomography (CBCT) images for evaluating canalis sinuosus (CS), determine its location and diameter in relation to gender, age, and distances from important structures, including floor of nasal cavity, incisive foramen, edge of buccal cortical bone, and palatal cortical bone. The scans of 650 patients in total were included in this prospective analysis. Gender, age, the position of the CS, its presence or absence, diameter, and its location in reference to the adjacent teeth were the factors that were noted. The study had 301 female participants and 349 male participants, with a mean age of 42.19. Compared to females, males had a statistically higher frequency of CS. Higher age groups showed a higher presence of CS in comparison to the other age groups. The mean distances of these parameters on the left and right side did not differ significantly. Nonetheless, the distance on both sides between CS and nasal cavity floor for males and females, as well as the diameter and border of buccal-palatal cortical bone on the right side, were statistically significant different. On the left side, both genders demonstrated significance in buccal cortical margin and nasal cavity floor. IIn addition, in females, the diameter of the CS on the right and left sides differed on average. The associations between age and number of CS, CS diameter, and number of CS versus sex were all extremely weak. Overall, the study findings showed that CS is a typical anatomical feature in anterior maxillary region, irrespective of age, or gender. The bony canal, CS is an obscure feature located in the frontal region of the maxilla. Surgeons can avoid complications by being aware of the auxiliary canals derived from this structure. With the use of CBCT, it is now feasible to examine the course of CS as it passes through the maxillary sinus's anterolateral wall with better radiological accuracy has already been documented.

Machine learning motivated data imputation of storm data used in coastal hazard assessments

In the Coastal Hazards System's (CHS) Probabilistic Coastal Hazard Analysis (PCHA) framework developed by the United States Army Corps of Engineers (USACE), historical records of tropical cyclone parameters have been used as data sources for statistical analysis, including fitting marginal distributions and measuring correlations between storm parameters. One limitation of the available historical databases is that observations of central pressure and radius of maximum winds are not available for a large number of storms. This may adversely affect the results of statistical analyses used to develop hazard curves. This study uses machine learning techniques to develop a data imputation method to “fill in” missing storm parameter records in historical datasets used for Joint Probability Method (JPM)-based coastal hazard analysis such as the USACE's CHS-PCHA. Specifically, Gaussian process regression (GPR) and artificial neural network (ANN) models are investigated as candidate machine learning-derived data imputation models, and the performance of different model parameterizations is assessed. Candidate imputation models are compared against existing statistical relationships. The effect of the data imputation process on statistical analyses (marginal distributions and correlation measures) is also evaluated for a series of example coastal reference locations.

Bioaccumulation of heavy metals and petroleum hydrocarbons in the blue crab (&lt;i&gt;Callinectes sapidus&lt;/i&gt;, Rathbun 1896) from Ogu Creek in Upper Bonny Estuary, Nigeria

Prolonged industrial and artisanal discharge of petroleum refinery effluents into the Ogu Creek at the Upper Bonny estuary of the Niger Delta could pose a great threat to the aquatic biotopes. This research investigated bioaccumulation of selected heavy metals and petroleum hydrocarbons in the blue crab (Callinectes sapidus) from the creek. Crabs (N=20; average length 18±20cm; weight 150.18±0.02g) were collected with nets. Mean concentrations (mg/l) of Zn (0.044±0.01), Cd (0.002±0.00), Cr (0.001±0.00), Pb (0.001±0.00), Fe (5.82±0.29), Mn (0.001±0.00), total petroleum hydrocarbons (TPH; 40.23±2.83) and total polynuclear aromatic hydrocarbons (ΣPAHs;7.60±1.29) were lower in water than sediments (22.10±1.37, 1.98±0.04, 2.13±0.09, 4.80±0.57, 24.03±1.29, 0.04±0.01, 70.93±3.10 and 29.80±4.02mg/kg, respectively) at the impacted location. Accumulations (μg/g) in digestive tract (dtr), muscle (mus) and ovaries (ov) were as follows: Zn 10.50 (dtr), 11.00 (mus), 2.40 (ov); Cr 0.21 (dtr), 0.10 (mus), 0.04 (ov); Cd 0.01 (dtr), 0.02 (mus), 0.01 (ov); Pb 0.04 (dtr), 0.02 (mus), 0.01 (ov); Mn 0.05 (dtr), 0.03 (mus), 0.01 (ov); TPH 4.14 (dtr), 3.14 (mus), 1.20 (ov); and mononuclear aromatic hydrocarbons (MAHs=BTEX) 0.01μg/g (dtr), 0.02 μg/g (mus), 0.01 μg/g (ov). Accumulations of TPH and BTEX were significantly (p&lt;0.05) higher at the impacted location (p = 0.03 and 0.02, respectively) than reference locations. High TQ/HQ values of 1.59, 2.82 and 1.90 were recorded for Zn, TPHs and PAHs, respectively. The results raise environmental health concerns among consumers of the aquatic food in the area.

Understanding earthquake location uncertainties using global sensitivity analysis framework

SUMMARY Earthquake hypocentres are routinely obtained by a common inversion problem of P- and S-phase arrivals observed on a seismological network. Improving our understanding of the uncertainties associated with the hypocentral parameters is crucial for reliable seismological analysis, understanding of tectonic processes and seismic hazard assessment. However, current methods often overlook uncertainties in velocity models and variable trade-offs during inversion. Here, we propose to unravel the effects of the main sources of uncertainty in the location process using techniques derived from the Global Sensitivity Analysis (GSA) framework. These techniques provide a quantification of the effects of selected variables on the variance of the earthquake location using an iterative model that challenges the inversion scheme. Specifically, we consider the main and combined effects of (1) variable network geometry, (2) the presence of errors in the analyst’s observations and (3) errors in velocity parameters from a 1-D velocity model. These multiple sources of uncertainty are described by a dozen of random variables in our model. Using a Monte Carlo sampling approach, we explore the model configurations and analyse the differences between the initial reference location and 100 000 resulting hypocentral locations. The GSA approach using Sobol's variance decomposition allows us to quantify the relative importance of our choice of variables. It highlights the critical importance of the velocity model approximation and provides a new objective and quantitative insight into understanding the sources of uncertainty in the inversion process.