Lower Belt Research Articles

Characteristics of Metamorphic Rocks and the Deformation and Metamorphism Period in Northern Lhasa,Tibet

The study of metamorphic rocks and deformation and metamorphic features in Gangdise-Lhasa metamorphic zone is helpful for the establishment of regional tectonic framework and the discussion of the evolution history of the region, which will provide new basic data for the study of geological structure evolution in the Qinghai-Tibet Plateau. There are few studies on metamorphic rocks in the northern area of Lhasa, Tibet. This paper summarizes and studies them from the perspective of petrography, and briefly discusses the stages of deformation and metamorphism. The area is divided into two metamorphic belts, which are divided into Yebagou-Gandansi metamorphic belt and Shexing-Binjiaolin metamorphic belt from south to north. The types of metamorphic rocks are slate, kyanite and schist. The dynamic metamorphism is manifested as brittle deformation and ductile deformation. The dynamic metamorphic rock belt developed in the area is several kilometers long, which basically belongs to the low green schist facies belt. The metamorphism in the area occurs under the geological background of the northward subduction, subduction and collision of the Neotethys oceanic crust plate. And with the change of tectonic environment and heat flow, different metamorphisms are produced in different geological development stages.

DISTRIBUTION REGULATIONS AND LIFE FORMS OF THE SPECIES OF THE BERBERIDACEAE JUSS. FAMILY WHICH ARE DISTRIBUTED IN THE NAKCHIVAN AUTONOMOUS REPUBLIC OVER ALTITUDE ZONES

Nakhchivan Autonomous Republic, which is part of Azerbaijan, has unique physical and geographical conditions. The total length of the border lines of the autonomous republic, located in the south west of the Lesser Caucasus, is 398 km. The main plain of the Autonomous Republic, 2/3 of which is mountainous and 1/3 is plain, is Araz-Long Plain, which in turn is divided into Ordubad, Nakhchivan, Sharur, Sadarak and other small Plains. Due to the fact that the territory of Nakhichevan Autonomous Republic consists of mountainous and lowland areas, the vegetation cover was formed in accordance with these conditions. The north-eastern territories of the autonomous republic, being part of the high mountain belt, cover heights of more than 2500 meters, and the Alpine and subalpine meadows of the Zangazur and Daralayaz ranges included here cover large areas. Plants belonging to the family Berberidaceae Juss. are distributed mainly in the middle and lower mountain belts, sometimes in the upper mountain belt, Alpine and subalpine belts on dry slopes, clayey, salty soils, Stony-gravel areas, as well as in arable land, field and grounds. In the article berberidaceae juss. The distribution of plants belonging to the family in the height zones, life forms have been studied and it has been determined that the species belonging to this family are most common in the middle and low mountain zones. Keywords: low mountain belt, barberry, height belts, shrub, Berberis vulgaris L., biological spectrum, distribution pattern.

Analysis of the noise mechanism and interactions of torsional decoupling devices in the belt driven 48V mild hybrid powertrain

This paper analyzed the mechanism of rattle noise from a decoupling damper pulley in a 48V belt driven mild hybrid powertrain with a three-cylinder turbo engine. To decouple the 48V belt drive from the high engine torque fluctuation of the engine, a decoupling device at the front end of engine is employed, which interacts with the rear end decoupling device and results in the rattling issue. In this study as opposed to the conventional engine torsional vibration studies which neglect the low inertia belt drive, the effective inertia of 48V belt drive is considered in 1D, 3D torsional vibration analyses of the entire powertrain as it easily reaches up to 20% of the whole torsional inertia. In this way, the impact inside the crank torque fluctuation decoupler was identified as the source of the rattle noise, which verified in the experiments. The interaction of the front end belt drive and the various types of rear end flywheel is also analyzed through parametric studies.

The increase in extreme precipitation and its proportion over global land

Changes in extreme precipitation (EP) have a significant impact on the ecology and sustainable development of most regions, especially when considered against a backdrop of global warming. Using trend analysis and other methods, we analyze the changes in nine extreme precipitation indices (EPIs), looking at the proportion of EP in total precipitation from the perspectives of intensity, frequency, and duration. We also utilize a geo-detector method to investigate the impacts of 15 climate factors on EPIs. Our results indicate that although EP and their proportions show an overall increasing trend on a global scale, they had undergone a process of initial decrease followed by increase over the past approximately 70 years. And this overall global increases are charged by the significant increases happened in Northern Hemisphere and western of South America, especially EP intensity and frequency indices, and their proportion. Whereas CDD shows an opposite trend in spatial distribution, the CWD is decreasing globally. The EPIs and their proportions are all highest in the low elevation belt (≤2000 m), followed by the high elevation belt (≥4000 m), and lowest in the mid-elevation belts (2000-4000 m). Most of them have returned to or exceeded the levels of the mid-20th century in all three elevation belts. Only CWD shows a decreasing trend, which indicates that more EP amounts are occurring with less precipitation duration. In some arid areas, this makes it possible that a short period of precipitation may complete the total amount of precipitation for that year. Global temperature is proven to be the most important factor influencing the EPI globally, and followed by the temperature of each region. And the regions of high latitudes of the Northern Hemisphere and Antarctica which are greatly influenced by global temperature demonstrate the Polar amplification effect. The East Atlantic-West Russia Pattern, Atlantic Multi-Decadal Oscillation, and El Nino-Southern Oscillation indices are the secondly important factors leading to changes in the proportion of global EP. At the same time, we also find that the influence of non-monsoon factors on EP is gradually strengthening. This study clarifies changes in EP globally and in various regions, which will help provide a scientific reference for preventing disasters caused by extreme climate change.

When sunlight goes out, avoidance mechanisms are defective for protecting flowers from freezing damage

In high mountain species, flowers are considered the most frost-sensitive organs of plants. Such frost sensibility relates to the fact that most flowers do not tolerate ice formation in their tissues, suggesting that freezing avoidance mechanisms would be highly selected to protecting these vital organs from freezing damage. Despite this, the function and regulation of avoidance mechanisms in flowers have been poorly studied. This study assessed the importance of freezing avoidance mechanisms in alpine species from the central Chilean Andes. Reproductive shoots of 14 herbaceous species from the subalpine and low alpine belts in the central Chilean Andes were collected during peak flowering in the field and transported to the lab to study ice formation and propagation. The frequency and effectiveness of structural ice barriers (SIB) and the effect of inflorescence morphology on thermal decoupling were quantified by infrared thermography. SIBs were detected in 9 out of the 14 studied species but were effective only in three. Moreover, no thermal decoupling was detected in any studied species, independent of their inflorescence type. We conclude that SIBs and inflorescence morphology are insufficient to protect flowers from damage caused by night freezing events.

Xylem formation patterns from Mediterranean to subalpine climate conditions reveal high growth plasticity of pine species on Corsica

Key messageBlack pine and Maritime pine exhibit considerable differences in growth phenology across elevation belts with a 1-month delay for xylogenesis and increasing growth rates from low, mid to high elevations.Investigating seasonal wood formation is crucial to understand tree growth responses to climate impact. The present study quantifies the variability of xylogenesis along an elevation gradient on the Mediterranean island of Corsica, where two native pine species (Pinus nigra Arnold ssp. laricio Maire and Pinus pinaster Aiton) grow from the upper tree line to sea level, partly in sympatry. We extracted microcores from 35 trees at 5 sites along an East–West transect from the coasts (10 m asl) to the island's central mountain ridge (1600 m asl) during bi-weekly sampling campaigns between 2017 and 2019. We applied generalised additive models to detect radial growth differences in elevation and species along with minimum temperatures for growth initiation. We found that trees in low elevations experienced over 2 months longer growth periods with higher maximum growth rates than in high elevations. The results show a 1-month delay for the beginning of tracheid formation between the low, mid and high-elevation belts but comparable timing for its termination. At the sites where both species co-occur, P. nigra accumulates more radial cells in a shorter time than P. pinaster. Trees at the two contrasting coastal sites have similar growth period lengths, but exhibit a time shift of over a month. Minimum temperatures around growth initiation vary between 3.1 °C for P. nigra and 9.9 °C for P. pinaster. These findings emphasise the high plasticity in the growth behaviour of one of the most widespread tree genera in Mediterranean and temperate zones.

Coseismic Deformation Field and Fault Slip Distribution Inversion of the 2020 Jiashi Ms 6.4 Earthquake: Considering the Atmospheric Effect with Sentinel-1 Data Interferometry

Due to some limitations associated with the atmospheric residual phase in Sentinel-1 data interferometry during the Jiashi earthquake, the detailed spatial distribution of the line-of-sight (LOS) surface deformation field is still not fully understood. This study, therefore, proposes an inversion method of coseismic deformation field and fault slip distribution, taking atmospheric effect into account to address this issue. First, an improved inverse distance weighted (IDW) interpolation tropospheric decomposition model is utilised to accurately estimate the turbulence component in tropospheric delay. Using the joint constraints of the corrected deformation fields, the geometric parameters of the seismogenic fault and the distribution of coseismic slip are then inverted. The findings show that the coseismic deformation field (long axis strike was nearly east-west) was distributed along the Kalpingtag fault and the Ozgertaou fault, and the earthquake was found to occur in the low dip thrust nappe structural belt at the subduction interface of the block. Correspondingly, the slip model further revealed that the slips were concentrated at depths between 10 and 20 km, with a maximum slip of 0.34 m. Accordingly, the seismic magnitude of the earthquake was estimated to be Ms 6.06. Considering the geological structure in the earthquake region and the fault source parameters, we infer that the Kepingtag reverse fault is responsible for the earthquake, and the improved IDW interpolation tropospheric decomposition model can perform atmospheric correction more effectively, which is also beneficial for the source parameter inversion of the Jiashi earthquake.

An In-Silico Study on the Therapeutic Effect of Low Back Belts: Biomechanical Correlation between Belt Design and Patient Morphology

A comparative study of eight different lumbar belts, which are representative of the French market, was carried out on four typical morphologies of patients to assess their therapeutic effects and identify the correlation between the therapeutic parameters and mechanical ones. Four typical morphologies were chosen among 15 patients that had been chosen for the clinical study: tall-large, small-large, tall-thin, and small-thin. Simplified 3D finite elements (FE) models of the trunk according to each patient’s morphology were used for numerical analyses using Abaqus SimuliaTM. The same material properties of the body structures and boundary conditions were taken for all models to only focus on morphological variations. The material properties of eight lumbar belts were obtained by mechanical testing. The pressure applied by the belt to the trunk was modelled by Laplace’s law. The influences of belt types on typical morphologies were analyzed and synthetized to show which parameters are significant for biomechanical efficacy and attendance to the therapeutic effects. Finally, we found the following belt effects: (i) the lumbar belt is more efficient on the thin morphology than the large one, (ii) all mechanical values checked on the vertebral disks and vertebrae have a strong correlation with the correction of lordosis angle, and (iii) the belt’s global stiffness is an important parameter for generating the pressure applied to the trunk.

Direct Evidence for Auroral Kilometric Radiation Propagation Into Radiation Belts Based on Arase Spacecraft and Van Allen Probe B

AbstractRecent studies have shown that auroral kilometric radiation (AKR) can propagate from the polar source cavity into the equatorial radiation belt but there is no direct evidence yet. By examining 19‐month data from Arase satellite and Van Allen Probes, we report a unique event that distinct AKR emissions are observed simultaneously at high and low latitudes, with the peak wave spectra in the frequency 300–400 kHz. Using the three‐dimensional ray tracing method, we simulate the AKR ray paths at three typical frequencies (220, 350, and 550 kHz), and show that more ray paths for 350 kHz can propagate downward through the locations of Arase satellite and Van Allen Probe B than those for other two frequencies. This result can successfully explain the observation and provides a direct evidence that AKR can propagate to low latitude radiation belt under suitable conditions.

Physical factors that differentiate body kinematics between treadmill and overground walking.

Treadmills are widely used in rehabilitation and gait analysis. However, previous studies have reported differences in terms of kinematics and kinetics between treadmill and overground walking due to physical and psychological factors. The aim of this study was to analyze gait differences due to only the physical factors of treadmill walking. Walking motions of a male participant were captured at 0.63, 1.05, 1.33, and 3.91 m/s. A gait controller of a virtual subject (63 kg) was trained for ground walking at each walking speed via a reinforcement learning method. Additionally, the gait controllers of virtual subjects with different body masses of 47, 79, and 94 kg were trained for ground walking at 1.05 m/s. The gait controllers and virtual subjects were tested for treadmill walking, and their lower-limb joint kinematics were compared with those for ground walking. Treadmill conditions of maximum allowable belt force and feedback control frequency of belt speed were set between 100 and 500 N and between 10 and 50 Hz, respectively. The lower-limb kinematics were identical between the two conditions regardless of the body mass and walking speed when the belt could provide a constant speed regardless of external perturbation in the ideal treadmill. However, kinematic differences were observed when simulation was performed on a non-ideal treadmill with a relatively low belt force and control frequency of belt speed. The root-mean-square differences of the hip, knee, and ankle flexion angles between treadmill and overground running at 3.91 m/s increased by 3.76°, 3.73°, and 4.91°, respectively, when the maximum belt force and control frequency decreased from infinity to 100 N and 10 Hz, respectively. At a maximum belt force exceeding 400 N or a control frequency exceeding 25 Hz, the root-mean-square difference of the joint kinematics was less than 3° for all body masses and walking speeds. Virtual subjects walking on non-ideal treadmills showed different joint kinematics from ground walking. The study identified physical factors that differentiate treadmill walking from overground walking, and suggested the belt forces and control frequencies of a treadmill to achieve the desired limit of kinematic differences.

A naturalistic study of passenger seating position, posture, and restraint use in second-row seats

Objective The objective of the current study was to increase scientific understanding of rear-seat passenger seating position, postures, CRS use, and belt use through a naturalistic study. A secondary objective was to compare data from vehicles used in ride-hailing with data from other vehicles. Method Video cameras were installed in the passenger cabins of the vehicles of 75 drivers near the center of the windshield. The video data were downloaded after the vehicles were operated by their owners for two weeks. Video frames were sampled from near the ends and in the middle of each trip, and at five-minute intervals in trips longer than 15 min. A total of 7,323 frames with second-row passengers were manually coded. Results A total of 444 unique second-row passengers were identified in video frames from 1,188 trips taken in 65 of the 75 vehicles in the study. Two of the vehicles that were driven for commercial ride-hailing during the study period accounted for 199 (45%) of the passengers. Considering multiple passengers in some trips, a total of 1,899 passenger-trips were identified. For passengers not using child restraint systems (CRS), the belt use rate was 65% in the non-ride-hailing vehicles versus 32% among passengers in the ride-hailing vehicles. No CRS use was observed in the ride-hailing vehicles. Among children using backless boosters, the shoulder belt was lateral to the clavicle or under the arm in 26% of frames. Among belted passengers not using CRS, the belt was lateral to the clavicle or on the neck about 6% of the time. Belted passengers not using CRS were observed leaning to the left or right about 27% of the time, with leaning away from the shoulder belt more common than leaning into the belt. Conclusions This study is the first to report seating position, posture, and belt fit observations for a large naturalistic sample of second-row passengers that includes adult occupants. The data suggest that low rear seat belt use rates remain a concern, particularly in ride-hailing vehicles. Non-nominal belt placement and posture may also be common in second-row seating positions.

The Impacts of El Nino and La Nina on the Global Weather Condition and Possible Remedial Measures

This research aims to investigate the socio-economic and political"impacts of El Nino and La Nina on" global weather conditions. The analogies El Nino - La Nina means "Little baby boy and Little baby girl" are the two different hot and cold climate patterns that developed in the Pacific Ocean due to the warm "Trade Wind", adversely affecting the global weather conditions.The trade winds are permanently flowing from the high-pressure area to low pressure belt between the latitudes of 30° and 40° N and S, bringing more rainfall and causing floods. This phenomenon of "El Nino and La Nina" has the worst impacts on global climate and weather conditions. This mixed high variations in the temperature, and up welling resulting the swear hurricanes in the Pacific Ocean, frequent tornado's in the Atlantic Ocean, destructive tropical cyclones and tsunamis in the Indo-Pacific and the hot surface of the oceanswater are the major indicators of increased global change in the weather conditions.

Numerical simulations of flow through a variable permeability circular cylinder

This paper investigates flow through variable permeability, two-dimensional circular cylinders using a pseudospectral numerical model. Two types of permeability (K) distributions are considered: constant with a lower permeability blockage, and constant with a higher permeability duct. Boundary conditions set by external flow with high Reynolds number lead to streamwise flow asymmetry and more short length scale variability within the cylinder when compared to conditions set by potential flow. High permeability belts are observed to guide flow around regions of lower permeability, while low permeability belts are observed to impede flow from reaching areas surrounded by the low permeability region. Inward surface flux is used to quantify changes in flow through variable permeability cylinders relative to the constant permeability cylinder. For blocking cases, the relationship between ΔK/K0 and the largest possible change in relative surface flux is nearly linear. In ducting simulations, where ΔK/K0∼1 to ∼10, this relationship is no longer linear. Simple polynomial fits are derived for both situations, allowing for the calculation of the change in permeability required to achieve a given increase or reduction in inward flux. Finally, the numerical results are contrasted with theoretical perturbation results for the case of azimuthal variations in permeability, which lead to a fundamentally different pressure distribution.

Tracking the dynamics of paddy rice cultivation practice through MODIS time series and PhenoRice algorithm

Monitoring paddy rice cultivation is essential for ensuring food security and for land resource management in agrarian countries of South Asia. In this study, we investigated the spatial and temporal variation of rice cultivated area and phenological metrics in Nepal between 2003 and 2018 using the time series MODIS data and PhenoRice algorithm. Comparisons of PhenoRice outputs with ancillary data show that implementation of PhenoRice with the MODIS data can be used for long-term change analysis of rice cultivation. Results on spatial distribution illustrate: rice cultivation is concentrated in the low elevation belt in the south; the cultivation begins earlier in the western region compared to the eastern region and begins earlier in the hilly region compared to the plains. The inter-annual trend analysis found a statistically significant decrease of rice cultivated area at the rate of 19.13 thousand hectares per year during the recent decade; the loss of rice fields was more prominent in the eastern plains while rice farming expanded in the mid-hills in the western region. Our study provides insights regarding timely and cost-efficient monitoring of rice farming at a large scale in the mountainous region.

Evaluation of dietary diversity of rural residents in Arun Banner, a typical area of low selenium belt in China

To understand the dietary diversity and food sources of different groups in Arun Banner. Comparing and analyzing the changes of dietary diversity of local residents in different periods. In October 2019, according to the differences of Kashin-Beck disease conditions and land use patterns of Arun Banner, Hulun Buir, 78 rural residents were randomly selected from four villages to investigate the frequency of daily food consumption by using self-made food frequency questionnaire. Dietary diversity score(DDS) was used to evaluate the dietary diversity of different populations. The average DDS of the investigated residents was 9. 76±2. 32. DDS of the residents of Minzu and Tieshan villages(10. 14±2. 66) in the West was higher than that of Longtoushan and Hongqi villages(9. 42±1. 95) in the East. However, the difference was not statistically significant(Z=-1. 875, P& gt; 0. 05). DDS in males(10. 37±2. 47) was significantly higher than that in females(9. 36±2. 14)(P& lt; 0. 05). There was no significant difference in DDS(9. 52±2. 29) between Kashin-Beck disease affected patients and healthy residents(9. 85±2. 34)(Z=-0. 601, P& gt; 0. 05). There was no significant difference in DDS among different age groups. The average of DDS was higher in those younger than 60 years old(9. 90±2. 35). Residents mainly eat rice and flour, and the proportion of purchasing food from other places reaches 96% and 95%, respectively. The staple food in Arun Banner was mainly rice and flour purchased from other places. The dietary structure of residents tends to be diversified. Residents reduced dependence on low selenium natural environment is an important factor for local selenium-susceptible endemic diseases to be stable and gradually controlled.

Acute injuries in American collegiate taekwondo competitions: a prospective study spanning four competitive seasons.

Injury patterns are well-documented for taekwondo competitions prior to the use of an electronic chest protector for scoring tabulation. To see if injury rates and types changed following this rule change that transformed the fighting style in taekwondo, we investigated injuries in collegiate taekwondo competitions in the USA. Data were collected at eight collegiate taekwondo tournaments from April 2018 to December 2019. All injured athletes seen at the first-aid station were invited to complete a survey that included injury location, type, and mechanism of injury. Injury rates were calculated per 1000 athlete-exposures (A-Es) and minute-exposures (M-Es). Risk factors were modeled using logistic regression and χ2 analysis. Out of 1096 athletes, 194 athletes reported 275 acute injuries. We found an injury risk of 17.7/100 athletes (95% CI: 15.4, 20.0) and injury rate of 68.9/1000 A-E (95% CI: 60.7, 77.0) which was comparable to previous studies. The most common injuries were contusions to the lower limbs. In contrast to prior reports, men were injured more frequently from delivering a kick and women from receiving a kick. Populations at higher risk for injury included those with low belt rank and middle weight class for women. It appears that the new fighting style did not affect injury rates. Injury locations and types remain similar, but the mechanisms of injury have reversed as men are more injured from attacking and women from defending. There remains a strong need for research to improve protective equipment and safety rules in taekwondo.

Evaluation of exergy performance and onion drying properties in a multi-stage semi-industrial continuous dryer: Artificial neural networks (ANNs) and ANFIS models

In this research work, two intelligent methods, namely artificial neural networks (ANNs) and adaptive neuro-fuzzy inference system (ANFIS) are applied to predict the moisture ratio (MR), energy utilization (EU), energy utilization ratio (EUR), exergy loss and exergy efficiency of onion slices drying process by a Multi-Stage Semi-Industrial Continuous Belt (MSSICB) dryer. The experiments are carried out for various temperature levels (40, 55, 70°C), air velocities (0.5, 1, 1.5m/s) and belt linear speeds (2.5, 6.5 and 10.5mm/s). The results demonstrate that by using the high levels of air temperature and velocity along with a low belt linear speed, the values of effective moisture diffusivity (Deff), color change (ΔE), EU, EUR, and exergy loss increase whereas the drying time, specific energy consumption (SEC) and exergy efficiency decrease. The highest values of Deff, SEC and ΔE are found to be 3.74×10−11m2/s, 484.54MJ/kg and 23.65, respectively. EU and EUR vary between 0.0641 to 0.2451kJ/s and 0.0848 to 0.5028, respectively. Moreover, exergy loss and efficiency vary in the ranges [0.0182−0.0555] kJ/s and [62.33–89.25] %, respectively. Moreover, the results showed that the prediction accuracies of MR, EU, EUR, exergy loss and exergy efficiency by the use of ANNs model were 0.9995, 0.9957, 0.9984, 0.9960 and 0.9979, respectively so that the values of 0.9998, 0.9972, 0.9991, 0.9962 and 0.9985, obtained by application of ANFIS model, respectively. Therefore, the selected ANN and ANFIS models can be used confidently to estimate the exergy efficient drying conditions for a sustainable drying process by MSSICB.

Are populations of Polylepis australis locally adapted along their elevation gradient?

ABSTRACT Mountain ecosystems are characterized by steep environmental gradients. Species with broad elevation distribution are exposed to contrasting climatic conditions along their gradients. In response to those changes, species might develop ecotypes adapted to the local climate. Early regeneration is the most critical stage for plant populations and, therefore, withstands strong selection pressures. Previous studies showed a unimodal pattern of intraspecific variability in fitness components among Polylepis australis populations along their elevation gradient in the mountains of central Argentina. Whether this variability is the result of local populations’ adjustments to their respective site remains unknown. We tested the hypothesis that P. australis populations from different elevations would be locally adapted to their local environments, where they would perform better than populations from other elevations (origins). We applied an experimental approach by establishing common gardens at three contrasting elevations. Seeds and saplings of P. australis populations from the low, mid- and high elevation belts of the species distribution gradient (i.e. three origins) were reciprocally sown and transplanted in three elevation sites (low, mid- and high). Seed germination success, sapling growth and mortality were monitored for three years. Our main results show that the origin of populations influenced germination success and sapling growth, whereas sapling mortality was marginally affected. Populations of both elevation extremes seem to be more adjusted to local conditions than the population from the intermediate elevation, probably due to the harsher environmental conditions for plant regeneration typical of the lower and upper elevation belts of semiarid mountains. Finally, our results strongly suggest that temperature rise due to climate change in this mountain area might have negative effects on the regeneration of P. australis populations.

Dynamics of river plumes in the South Brazilian Bight and South Brazil

The plumes from the rivers of the South Brazilian Bight (SBB) and South Brazil (SB) were studied using a realistic model configuration. River plume variability on continental shelves is driven by the input of river runoff into the shelf, by wind variability, and also by ambient currents and its seasonal variability, especially the Brazil Current, which are realistically modelled in this study. It is presented a simulation of 4 years using a nested configuration, which allows resolving the region around Florianópolis with very high resolution (∼150 m). The dispersion of river plumes was assessed not only with the hydrodynamical model results but also by using passive tracers whose dynamics was analyzed seasonally. Several dyes were released together with the river discharges. This approach allowed calculating the depths of the riverine freshwater, and the resulting regions affected by the plumes. Northward intrusions of waters from the southern region, under the potential influence of the distant La Plata river plume, were evaluated with a Lagrangian approach. The local river plumes are confined to the inner shelf, except south of 30°S where discharges from Lagoa dos Patos disperse over the shelf in the spring and summer. The Brazil Current flowing southward over the slope prevents the river plumes from interaction with oceanic mesoscale dynamics. The river plumes are, thus, mainly controlled by the wind forcing. The plumes from SBB are able to disperse until SB following the southward wind regime typical of the summer. And both the SB and La Plata river plumes are also able to reach SBB, forced by the northward wind typical of the winter season, until the latitude of 25.5°S. A low salinity belt (below 35) is present along the coastal region of SB and SBB year-round, supported by contributions from both the large and small rivers. The interaction between the different plumes influences the dispersion patterns, shielding the Florianṕolis coastal region from plumes of distant rivers, and dispersing the plume of SBB rivers away from Santa Catarina Island as it disperses southward during the summer months.

Key driving factors of selenium-enriched soil in the low-Se geological belt: A case study in Red Beds of Sichuan Basin, China

Selenium (Se) is an essential micronutrient for humans given its varying health benefits. It is generally recognized that China has a wide belt of low-Se soil stretching from the northeast to southwest. Nevertheless, there are Se-enriched areas distributed in the low-Se belt of China. However, the quantificational relationships among soil properties, topographic characteristics, parent materials, land use and soil Se content in those Se-enriched soils remain to be elucidated. Similarly, the key driving factors of the Se-enriched soil in the low-Se geological belt need to be documented. These aims could be an useful basis for evaluating the health of the soil ecosystem (in terms of Se toxicity or deficiency) and the potential intake of Se by humans from soils to food crops and animal products. To solve the above questions, Jiangjin district, Chongqing City, as an area in low Se red beds, was selected, and 156 topsoil samples were collected to explore the relationships between Se content in topsoil under various land use type and soil properties (pH, organic matter (OM), major elements content in topsoil) and topographic characteristics such as elevation (H), slope (SL), and topographic wetness index (TWI) and geological condition (stratum). Geostatistics, principal component analysis (PCA) and Geodetector were used to analyze the controlling factors of Se distribution in topsoil. The results show that in the analyzed topsoil (1) Se contents vary from 0.039 to 1.110 mg/kg, with a mean of 0.315 mg/kg, and higher than the background value of Chinese soil (0.290 mg/kg). 82.3% are classified as having moderate Se levels (Se > 0.175 mg/kg). (2) The Se contents in northeast of Jiangjin district are higher (Se > 0.315 mg/kg) than the midwest (Se < 0.315 mg/kg). (3) The key controlling factor of the soil Se distribution is OM. In addition, the soil weathering and leaching process and pedogenic rock are the secondary factors controlling Se distribution. Together, these findings reveal that Se-rich soil of low Se belt tends to be distributed in regions with higher OM, stronger leaching, and carbonate parent materials. These observations are beneficial to explore the Se-rich soil resources in low Se region in China.