Depth Distribution Research Articles

Research on charging demands of commercial electric vehicles based on Voronoi diagram and spatial econometrics model: An empirical study in Chongqing China

In order to address the mismatch between the current charging demand of electric vehicles and the layout of charging stations, this paper collects multi-source heterogeneous data that may affect charging demand, and explores their spatiotemporal distributions in depth. Then, this paper proposes a Voronoi polygon spatial partitioning method based on charging demand clustering and two spatial econometric models, spatial lag model (SLM) and spatial error model (SEM), to quantitatively analyze the influences of various elements on charging demands. Empirical research in Chongqing, China reveals that the spatiotemporal distribution of charging demand is uneven, with peak areas and periods for charging, and the division of Voronoi polygon can better reflect the spatial heterogeneity of charging demands than regular grid division. The positive factors include the low SOC, parking lot density, population density, and road network density, especially the low SOC and parking lot density, and the negative items contain consumption related Point Of Interest (POI), tourism related POI, and transportation hub related POI. Among them, population density and road network density, as static data, have similar influences on charging demands at different intervals, while the impact of other factors on charging demand varies with periods, with obvious peak-valley characteristics. There is spatial dependence and lag effect between charging demands within polygons, causing SLM outperforms SEM. The research results are beneficial for the rational siting and optimization of charging stations.

Depth distribution and depth adaptation of microbiomes in juvenile and adult scleractinian corals (Pocillopora verrucosa) in the central South China Sea

Depth distribution and depth adaptation of microbiomes in juvenile and adult scleractinian corals (Pocillopora verrucosa) in the central South China Sea

Chinook salmon depth distributions on the continental shelf are shaped by interactions between location, season, and individual condition

BackgroundEcological and physical conditions vary with depth in aquatic ecosystems, resulting in gradients of habitat suitability. Although variation in vertical distributions among individuals provides evidence of habitat selection, it has been challenging to disentangle how processes at multiple spatio-temporal scales shape behaviour.MethodsWe collected thousands of observations of depth from >300\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$>~300$$\\end{document} acoustically tagged adult Chinook salmon Oncorhynchus tshawytscha, spanning multiple seasons and years. We used these data to parameterize a machine-learning model to disentangle the influence of spatial, temporal, and dynamic oceanographic variables while accounting for differences in individual condition and maturation stage.ResultsThe top performing machine learning model used bathymetric depth ratio (i.e., individual depth relative to seafloor depth) as a response. We found that bathymetry, season, maturation stage, and spatial location most strongly influenced Chinook salmon depth. Chinook salmon bathymetric depth ratios were deepest in shallow water, during winter, and for immature individuals. We also identified non-linear interactions among covariates, resulting in spatially-varying effects of zooplankton concentration, lunar cycle, temperature and oxygen concentration.ConclusionsOur results suggest Chinook salmon vertical habitat use is a function of ecological interactions, not physiological constraints. Temporal and spatial variation in depth distributions could be used to guide management decisions intended to reduce fishery impacts on Chinook salmon. More generally, our findings demonstrate how complex interactions among bathymetry, seasonality, location, and life history stage regulate vertical habitat selection.

Hemispherically symmetric strategies for stratospheric aerosol injection

Abstract. Stratospheric aerosol injection (SAI) comes with a wide range of possible design choices, such as the location and timing of the injection. Different stratospheric aerosol injection strategies can yield different climate responses; therefore, understanding the range of possible climate outcomes is crucial to making informed future decisions on SAI, along with the consideration of other factors. Yet, to date, there has been no systematic exploration of a broad range of SAI strategies. This limits the ability to determine which effects are robust across different strategies and which depend on specific injection choices. This study systematically explores how the choice of SAI strategy affects climate responses in one climate model. Here, we introduce four hemispherically symmetric injection strategies, all of which are designed to maintain the same global mean surface temperature: an annual injection at the Equator (EQ), an annual injection of equal amounts of SO2 at 15° N and 15° S (15N+15S), an annual injection of equal amounts of SO2 at 30° N and 30° S (30N+30S), and a polar injection strategy that injects equal amounts of SO2 at 60° N and 60° S only during spring in each hemisphere (60N+60S). We compare these four hemispherically symmetric SAI strategies with a more complex injection strategy that injects different quantities of SO2 at 30° N, 15° N, 15° S, and 30° S in order to maintain not only the global mean surface temperature but also its large-scale horizontal gradients. All five strategies are simulated using version 2 of the Community Earth System Model with the middle atmosphere version of the Whole Atmosphere Community Climate model, version 6, as the atmospheric component, CESM2(WACCM6-MA), with the global warming scenario, Shared Socioeconomic Pathway (SSP)2-4.5. We find that the choice of SAI strategy affects the spatial distribution of aerosol optical depths, injection efficiency, and various surface climate responses. In addition, injecting in the subtropics produces more global cooling per unit injection, with the EQ and the 60N+60S cases requiring, respectively, 59 % and 50 % more injection than the 30N+30S case to meet the same global mean temperature target. Injecting at higher latitudes results in larger Equator-to-pole temperature gradients. While all five strategies restore Arctic September sea ice, the high-latitude injection strategy is more effective due to the SAI-induced cooling occurring preferentially at higher latitudes. These results suggest trade-offs wherein different strategies appear better or worse, depending on which metrics are deemed important.

Competition between ocean thermal structure and tropical cyclone characteristics modulates ocean environmental responses in the Yellow and Bohai Seas

To study the environmental responses of tropical cyclones (TCs) in continental shelf regions, TCs passing over the Yellow Sea and Bohai Sea (YBS) during 2002–2020 were investigated, with a special focus on how competition between ocean thermal structure and TC characteristics modulates ocean surface changes. The spatial distributions of the climatic mixed layer depth (MLD), accumulated wind forcing power index (WPi), accumulated sea surface temperature (SST) changes and accumulated chlorophyll (Chl-a) changes in the YBS were calculated. The linear regressions indicate that both the TC-induced SST cooling and TC-induced Chl-a increase are correlated with the TC wind speed rather than the translation speed, especially when the TC forcing depth (Zmixing) is greater than the MLD. Otherwise, both the changes in SST and Chl-a are correlated with the TC translation speed when Zmixing is shallower than the MLD. Further study has shown that whether TCs can break the MLD is also a key condition for oceanic responses. In the southern YBS, which has a deep-sea basin and MLD, the TC wind speed is the major factor affecting SST cooling and Chl-a increase, as TCs need more strength to reach the MLD. However, in the northern YBS, which has the shallowest sea basin and MLD, even weak TCs can easily break the MLD and reach the seabed; thus, ocean surface changes are associated mainly with the TC translation speed. The composite results reveal that both the maximum SST cooling center (1.64 °C) and the maximum Chl-a increasing center (0.14 log10(mg/m3)) are located on the right and behind the TC center, respectively. In addition, TC-induced SST cooling and Chl-a increase were initiated two days prior to TC passage and then reached their maximum values after 1 day. It takes approximately 7–8 days for the Chl-a concentration to recover, but it takes a much longer time (>15 days) for the SST to recover.

Toward deeper ultraviolet detection: Atomic layer deposited amorphous AlGaOx thin film detector with its tunable optical properties and opto-electronic responses

Employing atomic layer deposition, AlGaOx films with varying Al concentrations (highest to 44% at.) were meticulously synthesized. Comprehensive characterization encompassing chemical composition, elemental depth distribution, structural clarity, and interface delineation unequivocally attested to the superior quality of the films. Optical properties were rigorously assessed using transmittance spectra and spectroscopic ellipsometry (SE), and optical constants across a broad spectral range (200–1000 nm) were determined through SE fitting. A consistent blue-shift in the absorption edge, observed in both the transmittance spectra and extinction coefficient, is attributed to the incorporation of aluminum. Detailed exploration via X-ray photoelectron spectroscopy fine scans of O 1s energy loss spectra and valence band analysis revealed that the evolution of the conduction band is instrumental in modulating the bandgap. To ascertain the viability for deep ultraviolet light detection, photodetectors based on AlGaOx were fabricated. Blue shifts in both photocurrent and response peak wavelength correlated with increasing Al content. In specific occasions, the AlGaOx-based detector has a responsibility of 0.05 A/W and 7×1013 detectivity of Jones. Remarkably, the detector demonstrates commendable on/off capability, characterized by fast rise and decay times of 0.26 s and 0.17 s, respectively. This study extensively examined the chemical, structural, and optical properties of amorphous AlGaOx films, alongside the optoelectronic capabilities of AlGaOx-based devices. Our research presented a viable strategy for enhanced deep ultraviolet detection, showcasing a successful implementation of amorphous bandgap engineering. This endeavor holds promise for future advancements in UV-detector development.

Fluctuations in abundance of the striped venus clam Chamelea gallina in the southern Adriatic Sea (Central Mediterranean Sea): knowledge, gaps and insights for ecosystem-based fishery management

An assessment on the fluctuations in abundance of the striped venus clam (Chamelea gallina) in the southern Adriatic Sea (Central Mediterranean Sea), and the northern Gargano area, has been conducted through both historical information and recent data from monitoring surveys during the period 1997–2019. Production trends, conditions of the commercial stock biomass, and depth distribution pattern of juveniles and commercial sizes were analysed testing temporal differences. Moreover, the exploitation of the clam beds and recruitment events were investigated in 2018–2019. Changes in abundance were analysed using non-parametric tests for both juvenile (length class, LC < 22 mm) and commercial (LC ≥ 22 mm) fractions. Hydrodynamic changes, temperature and salinity variations were explored using a 3D hydrodynamic numerical model (MIKE 3 FM-HD) and statistical analysis, as well as changes in benthic assemblages impacted by hydraulic dredges were investigated through PERMANOVA and other multivariate analysis.The results showed a temporal decline of production and biomass of C. gallina during the 1997–2019 period, and a regression of the depth limit in the clams’ distribution towards shallower waters. A significant reduction in juveniles was observed during 2018–2019 with a very limited recruitment. The fishing exploitation showed high impacts on the commercial stock and benthic assemblages in the summer of 2018. Overall, water currents were predominantly directed offshore in 2018, during the C. gallina spawning period. This could affect the larval dispersal and settlement on unsuitable bottoms. Anomalies in temperature (high peaks in August 2018, > 28 °C) and salinity (low values in spring 2018, < 37 PSU) could have induced stress and mortality events on the entire clam bed in the study area. This first study highlights the need to integrate environmental information in the assessment of commercial stocks of clams in the Adriatic Sea, to better understand climate change effects on the fluctuations and to support effective ecosystem-based fishery management.

Two‐stage soil core sampler to collect a less‐compressed core from forested areas

AbstractA two‐stage sampler was designed to investigate the vertical distribution of heavy metals and trace elements that contaminate forest soils through atmospheric deposition. The hand‐corer consisted of two L‐shaped aluminum angles that were driven separately into the soil to reduce friction between the corer wall and the soil. This allowed for soil cores to be collected with less compression than with traditional corers. The corer is easily made, inexpensive, lightweight, and easy to carry. The degree of compression of soil cores collected at a depth of 20 cm from various montane forests in Japan was usually less than 10% (collected core length &gt;18 cm); although, more compression occurred in soil with a higher air content. The degree of compression of soil cores collected from urban forests was lower than that in montane forests. When the two‐stage sampler was compared with a tube‐type sampler in a Japanese cedar (Cryptomeria japonica) forest, the compression degree of a soil core collected with the two‐stage sampler was a quarter that of the tube‐type sampler. The collection of less‐compressed soil cores will allow for reconstruction of a more accurate linear depth distribution of contaminants. To demonstrate this, we investigated the vertical distribution of Pb, Sb, and radioactive 137Cs in soil cores collected from conifer plantations on Mount Tsukuba, Japan, in April 2011. The migration centers of anthropogenic Pb, Sb, and 137Cs were positioned at 7.9, 7.5, and 3.3 cm from the ground surface, respectively. These distances probably reflect differences in the history of atmospheric pollution.

Residual Stress Engineering for Wire Drawing of Austenitic Stainless Steel X5CrNi18-10 by Variation in Die Geometries-Effect of Drawing Speed and Process Temperature.

As a result of conventional wire-forming processes, the residual stress distribution in wires is frequently unfavorable for subsequent forming processes such as bending operations. High tensile residual stresses typically occur in the near-surface region of the wires and can limit further application and processability of the semi-finished products. This paper presents an approach for tailoring the residual stress distribution by modifying the forming process, especially with regard to the die geometry and the influence of the drawing velocity as well as the wire temperature. The aim is to mitigate the near-surface tensile residual stresses induced by the drawing process. Preliminary studies have shown that modifications in the forming zone of the dies have a significant impact on the plastic strain and deformation direction, and the approach can be applied to effectively reduce the process-induced near-surface residual stress distributions without affecting the diameter of the product geometry. In this first approach, the process variant using three different drawing die geometries was established for the metastable austenitic stainless steel X5CrNi18-10 (1.4301) using slow (20 mm/s) and fast (2000 mm/s) drawing velocities. The residual stress depth distributions were determined by means of incremental hole drilling. Complementary X-ray stress analysis was carried out to analyze the phase-specific residual stresses since strain-induced martensitic transformations occurred close to the surface as a consequence of the shear deformation and the frictional loading. This paper describes the setup of the drawing tools as well as the results of the experimental tests.

A variational optimization algorithm for Secchi disk depth based on Multi-satellite data

A Secchi depth is a basic parameter to describe the optical properties of water, which is related to the composition and content of chlorophyll, suspended solids and yellow substances in water, and is also closely related to solar radiation on the surface of water, physical and chemical properties of water and meteorological conditions. The most direct way to obtain the spatiotemporal distribution of water Secchi depth is to use ships to regularly measure the Secchi depth of the base-stations, but this method can only obtain the Secchi depth of the measurement station state, and it is impossible to obtain the Secchi depth characteristics of seawater with large spatiotemporal distribution. As a brand-new observation method, remote sensing technology can obtain the distribution characteristics of ocean parameters in large time and space. In recent years, with the rapid development of remote sensing technology, especially the development of water-colored remote sensors and the improvement of the accuracy of inversion algorithms, many remote sensing products for water Secchi depth have been provided. However, due to the difference in orbit operation and observation parameters of different remote sensing loads, water Secchi depth products are affected by clouds and meteorological climate environment, and there is no same standard for verification and evaluation, which limit the promotion and application of water Secchi depth products. At the same time, data integrated technology has been widely recognized by many disciplines and has been greatly developed in recent years, and pixel-level, feature-level, decision-level integrated technology and development are also popular research directions in the world. Therefore, based on an improved variational optimization algorithm, this article integrates SDD retrieval products on multiple satellite data t such as SNPP, MODIS, and MERIS, and verifies them with ship survey data. The correlation is better than 0.9, proving that this method can improve the accuracy of SDD inversion products.

Depth distribution of plant-parasitic nematodes on bentgrass golf greens in Missouri and Indiana.

Control of plant-parasitic nematodes (PPNs) on golf putting greens with nematicides is dependent on the seasonal occurrence and depth distribution of target PPN populations. This study aimed to determine if plant-parasitic nematode populations on golf course putting greens in Missouri and Indiana peaked at a targetable depth at a specific time in the year, focusing primarily on lance (Hoplolaimus spp.) and root-knot (Meloidogyne spp.) nematodes. To elucidate species diversity in the region, rDNA from a subset of lance and root-knot nematodes was sequenced and analyzed, with additional micromorphology of a lance nematode assessed in scanning electron micrographs (SEM). Soil samples were taken to a depth of 25 cm and stratified into 5 cm increments during April, June, August and October at seven sites across Missouri, three in the Kansas City metro of Kansas in 2021 and in ten sites across Indiana in 2022. Samples were stratified in five-centimeter increments and aggregated for a total of 100 cm3 of soil at each depth for each sampling. Samples were processed using a semi-automatic elutriator followed by the sucrose-flotation method, and populations were counted using a hemocytometer and recorded. For molecular characterization, rDNA was extracted and analyzed from 31 individual lance nematodes from one site in Missouri and eight sites in Indiana, and 13 root-knot nematodes from nine sites across Indiana. A significant interaction occurred between sampling month and depth for lance and ring nematodes Missouri/KS, with both PPN populations peaking at the 0-5 cm depth during October, which is well after most targeted nematicide applications are applied. Ring nematodes in Indiana did not follow this trend and were most abundant in August at a depth of 0-5 cm. No significant interaction between depth and month occurred for lance or root-knot nematodes in Indiana, or root-knot nematodes in Missouri/KS. Hoplolaimus stephanus and H. magnistylus were the lance species identified on golf greens, and Meloidogyne naasi, M. graminicola and M. marylandi were the root-knot species identified. Scanning-electron micrographs confirmed morphological characteristics unique to H. stephanus.

INVESTIGATION OF TEMPERATURE FIELDS DURING LOCAL INDUCTION HEATING OF THE CASING STRING IN THE WELL

One of the important tasks in geophysical studies of operating wells is the detection of behind the casing flows. The traditional complex of geophysical methods (thermometry, flow metering, composition methods, and others) does not always make it possible to detect the movement of fluid behind the well casing. To solve this problem, it is promising to use the method of active thermometry.Research technology using this method involves recording the temperature in the well during induction heating of a small section of metal casing. As a result of heat exchange between the heated section of the column and the liquid flow, a thermal disturbance is created in the annular flow channel. In the presence of behind the casing flow, heat will be carried away from the induction heating region in the direction of liquid movement and will be redistributed in the column above or below the heating interval. By recording the temperature of the casing during induction heating and after turning off the inductor, it is possible to establish the fact of cross-flow and quantify its flow rate.This paper studies the influence of the direction and flow rate of behind the casing flow on the unsteady temperature field in a metal casing during its local induction heating. The problem is solved numerically in the Ansys Fluent software package. The temperature field in the fluid in the wellbore is calculated taking into account free convection.The model temperature distributions obtained for different behind the casing flow configurations (direction, flow rate) can be used for quantitative interpretation, to determine the flow rate in the behind the casing flow channel by comparing actual and model temperature curves. To assess the intensity of behind-the-casing movement, time measurements at a “point” in the induction heating interval are also informative. The direction of flow is determined by the nature of the temperature distribution in depth above and below the induction heating section.

Introducing Pour Points: Characteristics and Hydrological Significance of a Rainfall‐Concentrating Mechanism in a Water‐Limited Woodland Ecosystem

AbstractThe interception of rainfall by plant canopies alters the depth and spatial distribution of water arriving at the soil surface, and thus the location, volume, and depth of infiltration. Mechanisms like stemflow are known to concentrate rainfall and route it deep into the soil, yet other mechanisms of flow concentration are poorly understood. This study characterizes pour points, formed by the detachment of water flowing under a branch, using a combination of field observations in Western Australian banksia woodlands and rainfall simulation experiments on Banksia menziesii branches. We aim to establish the hydrological significance of pour points in a water‐limited woodland ecosystem, along with the features of the canopy structure and rainfall that influence pour point formation and fluxes. Pour points were common in the woodland and could be identified by visually inspecting trees. Throughfall depths at pour points were up to 15 times greater than rainfall and generally comparable to or greater than stemflow. Soil water content beneath pour points was greater than in adjacent controls, with 20%–30% of the seasonal rainfall volume infiltrated into the top 1 m of soil beneath pour points, compared to 5% in controls. Rainfall simulations showed that pour points amplified the spatial heterogeneity of throughfall, violating assumptions used to close the water balance. The simulation experiments demonstrated that pour point fluxes depend on the interaction of branch angle and foliation for a given branch architecture. Pour points can play a significant part in the water balance, depending on their density and rainfall concentration ability.

Demersal Fish Community in the Near-Shelf Zone of the Cosmonaut Sea, Southern Ocean

Studies on the demersal fish composition of the East Antarctic nearshore region are very scarce due to the harsh physical geography of the East Antarctic region, which is covered in ice and snow year round, leading to a scarcity of scientific surveys. Based on the data from the bottom trawl survey conducted by the 37–38th Chinese National Antarctic Research Expedition (CHINARE) program in the Cosmonaut Sea, East Antarctica, the species of demersal fishes were identified, and the demersal fish composition and the characteristics of depth distribution were examined and analyzed. The basic biological information of highly abundant species was analyzed. The results from 97 individuals sampled within 30–60° E, south of −65° S, indicate that the fishes belong to 5 orders, 11 families, 19 genera, and 23 species. Most of the species are found in Myctophidae and Bathydraconidae, and the most common species is Macrourus whitsoni (Macrouridae). Macrourus whitsoni and Prionodraco evansii have a high abundance in the survey. Macrourus whitsoni has body lengths of 144–662 mm and body weights of 17.3–1425.1 g, and Prionodraco evansii has body lengths of 90.18–134.33 mm and body weights of 4.9–20.7 g. The length–weight relationships for Macrourus whitsoni and Prionodraco evansii are y=0.00002x2.748 and y=0.000006x3.353, respectively. All the Macrourus whitsoni samples were found in waters deeper than 1000 m, with the highest number of individuals captured at depths of 1500–2000 m. Prionodraco evansii was found only at stations less than 250 m deep. These results complement the demersal fish composition and distribution data of the Cosmonaut Sea, East Antarctica. These data can provide valuable basic information for characterizing regional assemblages and delineating zoogeographic boundaries.

Insights into swordfish (Xiphias gladius) movement patterns and habitat utilization off the coast of northern Chile

This study reports on the fine-scale movements of swordfish (Xiphias gladius) tagged off of the Antofagasta region of northern Chile, where harpoon fishing operations date back more than seven millenia. The study was conducted within a highly productive swordfish foraging area where movements and habitat use remain poorly characterized. Swordfish were outfitted with both data storage and satellite-linked archival tags scheduled for short (&lt;30 days) and longer-term (&gt;100 days) data collection. All tags were deployed on basking swordfish using harpoon-based methods across two field seasons in March 2019 and April 2022 around oceanic fronts and offshore seamounts. Fine-scale depth and temperature data were recorded over 145 days from four adult swordfish (100-200 kg). Swordfish exhibited regionally unique diurnal behaviors with greater average daytime depths than those recorded at night (78.0 ± 66.5 and 12.7 ± 4.9 m, respectively). The average daytime depths were shallower than those previously documented for other Pacific regions, including Chile's offshore waters. Daytime basking was observed on 76% of the daily records (110 out of 145 days) and accounted for approximately 12% of the collective daylight hours. Findings align with previous swordfish tagging studies and suggest that depth distribution patterns vary considerably depending on regional oceanographic conditions. Movement data are compared with previous studies, and we discussed relative to regional fishing operations.

Economic Loss due to the Failure of a Cascade Dam: A Study Case in the Saguling-Cirata-Jatiluhur Dam

A dam break event can cause heavy loss in the affected area due to the lack of a mitigation system. Therefore, modeling the possibility of a dam break occurrence requires a risk analysis. The Saguling Dam, Cirata Dam, and Jatiluhur Dam make a cascade dam and is one of the country's most valuable assets. This study simulates a flood induced by the failure of this cascade dam. The dam break is simulated using HEC-HMS 4.6 with several dam-break scenarios due to overtopping and piping. The scenario with the highest peak discharge is then used to simulate the overland flow using HEC-RAS 5.0.7, representing the most extreme condition when the dam break occurs. The generated flood induced by the dam break hit seven regencies with a total affected area of 1,596.59 km2. Moreover, an economic analysis is conducted. The result states that the most affected regency by economic losses is Karawang Regency, and the least affected is Subang Regency. The financial analysis, conducted using the ECLAC method, shows that the extent of inundation influences economic losses due to flooding, the distribution of depth, and the land cover of the affected area. This study hopes to assist in developing a mitigation plan for future possible dam breaks and provide a recommendation for decision-makers for developing land use areas.

Pin penetration depths in the neurocranium using a three-pin head fixation device

In estimated 10–15% of neurosurgical interventions employing a conventional three-pin head fixation device (HFD) the patient’s head loses position due to slippage. At present no scientifically based stability criterion exists to potentially prevent the intraoperative loss of head position or skull fractures. Here, data on the skull penetration depth both on the single and two-pin side of a three-pin HFD are presented, providing scientific evidence for a stability criterion for the invasive three-pin head fixation. Eight fresh, chemically untreated human cadaveric heads were sequentially pinned 90 times in total in a noncommercially calibrated clamp screw applying a predefined force of 270 N (approximately 60 lbf) throughout. Three head positions were pinned each in standardized manner for the following approaches: prone, middle fossa, pterional. Titanium-aluminum alloy pins were used, varying the pin-cone angle on the single-pin side from 36° to 55° and on the two-pin side from 25° to 36°. The bone-penetration depths were directly measured by a dial gauge on neurocranium. The penetration depths on the single-pin side ranged from 0.00 mm (i.e., no penetration) to 6.17 mm. The penetration depths on the two-pin side ranged from 0.00 mm (no penetration) to 4.48 mm. We measured a significantly higher penetration depth for the anterior pin in comparison to the posterior pin on the two-pin side in prone position. One pin configuration (50°/25°) resulted in a quasi-homogenous pin depth distribution between the single- and the two-pin side. Emanating from the physical principle that pin depths behave proportionate to pin pressure distribution, a quasi-homogenous pin penetration depth may result in higher resilience against external shear forces or torque, thus reducing potential complications such as slippage and depressed skull fractures. The authors propose that the pin configuration of 50°/25° may be superior to the currently used uniform pin-cone angle distribution in common clinical practice (36°/36°). However, future research may identify additional influencing factors to improve head fixation stability.

3D numerical modeling of wave–monopile–seabed interaction in the presence of a scour hole

Coastal engineers are deeply concerned about wave-induced seabed instability around monopile foundations. Most prior studies have primarily focused on the seabed response around monopiles on flat seabeds, often neglecting the presence of scour holes commonly found in engineering practice. This study thoroughly investigates seabed response and liquefaction around monopiles of scour holes. The examination involves analyzing 3D flow velocities, dynamic wave loads, pore pressures, soil effective stresses, and wave forces around a monopile with a scoured profile. The analysis uses a model that integrates the interactions between waves, seabed, and structures, and it is implemented within the OpenFOAM framework. The study meticulously assesses the impact of scour holes on seabed responses and liquefaction zones around monopile foundations. Numerical results reveal that: (1) The magnitude of the pore pressure within the scoured seabed is reduced relative to a flat seabed; (2) Considering the scour hole effect leads to a more uniform distribution of liquefaction depth around the monopile; (3) This effect intensifies with a higher saturation degree, while it exhibits a pattern of increase, followed by a decrease with an increase in permeability.

Population dynamics of dominant dinoflagellate species in the North Sea: in situ growth rates, photosynthetic potential, and losses due to parasitism

In the North Sea, Tripos and Dinophysis are commonly occurring mixotrophic planktonic dinoflagellate genera. In order to understand their bloom dynamics, an occurring bloom dominated by T. furca and D. norvegica was followed for several days. High cell abundances of these species were located to estimate: in situ growth rates from cell cycle analyses, depth distributions, growth rates sustained by photosynthesis, and parasite infection prevalence in all T. furca, T. fusus, D. norvegica and D. acuminata. Cell abundances were over 10000 cells L−1 for T. furca and up to 18000 cells L−1 for D. norvegica. Cells accumulated between 15-25 m depth and presented low specific in situ growth rates of 0.04-0.15 d−1 for T. furca and 0.02-0.16 d−1 for D. norvegica. Photosynthesis could sustain growth rates of 0.01-0.18 d−1 for T. furca and 0.02 to 0.14 d−1 for D. norvegica, suggesting that these species were relying mainly on photosynthesis. Parasite infections where generally low, with occasional high prevalence in D. norvegica (by Parvilucifera sp.) and T. fusus (by Amoebophrya sp.), while both parasites showed comparable prevalence in D. acuminata, which could offset in situ growth rates by parasite-induced host mortality. The restructuring effect of parasites on dinoflagellate blooms is often overlooked and this study elucidates their effect to cell abundances and their growth at the final stages of a bloom.

Bayesian physical–statistical retrieval of snow water equivalent and snow depth from X- and Ku-band synthetic aperture radar – demonstration using airborne SnowSAr in SnowEx'17

Abstract. A physical–statistical framework to estimate snow water equivalent (SWE) and snow depth from synthetic aperture radar (SAR) measurements is presented and applied to four SnowSAR flight-line data sets collected during the SnowEx'2017 field campaign in Grand Mesa, Colorado, USA. The physical (radar) model is used to describe the relationship between snowpack conditions and volume backscatter. The statistical model is a Bayesian inference model that seeks to estimate the joint probability distribution of volume backscatter measurements, snow density and snow depth, and physical model parameters. Prior distributions are derived from multilayer snow hydrology predictions driven by downscaled numerical weather prediction (NWP) forecasts. To reduce the signal-to-noise ratio, SnowSAR measurements at 1 m resolution were upscaled by simple averaging to 30 and 90 m resolution. To reduce the number of physical parameters, the multilayer snowpack is transformed for Bayesian inference into an equivalent one- or two-layer snowpack with the same snow mass and volume backscatter. Successful retrievals meeting NASEM (2018) science requirements are defined by absolute convergence backscatter errors ≤1.2 dB and local SnowSAR incidence angles between 30 and 45∘ for X- and Ku-band VV-pol backscatter measurements and were achieved for 75 % to 87 % of all grassland pixels with SWE up to 0.7 m and snow depth up to 2 m. SWE retrievals compare well with snow pit observations, showing strong skill in deep snow with average absolute SWE residuals of 5 %–7 % (15 %–18 %) for the two-layer (one-layer) retrieval algorithm. Furthermore, the spatial distributions of snow depth retrievals vis-à-vis lidar estimates have Bhattacharya coefficients above 94 % (90 %) for homogeneous grassland pixels at 30 m (90 m resolution), and values up to 76 % in mixed forest and grassland areas, indicating that the retrievals closely capture snowpack spatial variability. Because NWP forecasts are available everywhere, the proposed approach could be applied to SWE and snow depth retrievals from a dedicated global snow mission.