High Sediment Research Articles

The Mapping of Road Pavement Structure around the Seismically Active Regions by Using Ground Penetrating Radar

The Banda Aceh-Sigli Road has become the central infrastructure in connecting the capital city of Aceh province with other districts. In some places, the road construction was in rice fields dominated by high sedimentation areas. The Aceh also has the Great Sumatran Fault, which has caused many earthquakes and damaged public infrastructure, including roads. The density of the soil structure as an infrastructure buffer needs to be observed before road damage can endanger the community. This study aimed to apply Ground Penetrating Radar (GPR) as a non-destructive method that detects subsurface conditions based on permittivity parameters. The method is measured using the IDS Georadar Opera Duo instrument, which operates with a frequency of 250 MHz and 750 MHz for a penetration depth of 4 m, which is measured on eight intersecting tracks, where two profiles have a length of 110 m measured in the direction of the road segment and five tracks with a length of 11 m is measured by a cross. GresWin2 software is used for optimal analysis and modeling of 2D radargram. The radargram model describes a subsurface structure consisting of three layers, where the first layer with a depth of 0 – 0.25 m is asphalt, and the second and d layer with a depth of 0.25 – 0.75 m was identified as the base course layer. In comparison, the third layer is interpreted as a sub base course layer at a depth of 0.75 - 4 m below. The analysis results also show a linearly damaged road structure with high propagation speed and large wave amplitude. Therefore, based on data processing, it can be concluded that the application of GPR is a non-destructive, fast, and economical method for evaluating road structures.

Tidal control and mangrove dieback impact on methane emissions from a subtropical mangrove estuary

AbstractMangrove ecosystems with high sediment deposition and active carbon cycling are a source of methane (CH4) to the coastal atmosphere. We investigated diurnal and seasonal variations in CH4 emissions from a subtropical mangrove estuary in southern Texas, northwest Gulf of Mexico. Tidal processes, amplitude (spring vs. neap tides) and topographic characteristics are crucial factors controlling CH4 cycling in mangrove creeks. Higher CH4 concentrations were observed during the ebb in spring tides due to the combination of processive export of CH4 along the creeks during ebb tides and the addition of porewater CH4 in upper intertidal sediment under water inundation in spring tides. The annual CH4 emissions offset approximately 0.15% of the carbon stock in normal years, indicating that these mangrove creeks are a weak CH4 source. However, significantly elevated CH4 emissions were observed from mangrove dieback after the extreme cold‐freezing event in February 2021. The average CH4 flux from the mangrove creeks (126.1 ± 128.3 μmol [m2·d]−1) increased 45% in 3 months after mangrove die‐off in comparison with the overall average in normal years (87.0 ± 64.4 μmol [m2·d]−1). It is obvious that the previous small CH4 offset of the healthy mangrove forest was enlarged by the dieback event. Because the mangrove forests in this study live close to the limit of their survival range, our study highlights the important management considerations for blue carbon projects in vulnerable areas.

The effectiveness of sediment and phosphorus removal by a small constructed wetland in Norway: 18 years of monitoring and perspectives for the future

Constructed wetlands (CWs) are a widely recognised measure for reducing pollution loads and improving the quality of surface waters. The removal efficiency of CWs varies considerably depending on system type and design as well as residence time, hydraulic load, particles and nutrient loading rates. Therefore, there is a need to closely monitor the efficiency of existing measures, look at their efficiency in practice and be able to foresee potential implications for their efficiency in light of climate change and land management intensification.This study presents 18 years of data from a typical Norwegian small CW established in the Skuterud catchment. The main objective of this study was to look at the impact of hydraulic load, particles and nutrient loads (depending on climatic factors such as temperature and precipitation) on CW effectiveness. The results showed an average of 39 % and 22 % annual removal efficiency for sediment and phosphorus, respectively. It appears that good CW effectiveness coincides with a combination of high sediment or phosphorus loads to the CW and a stable runoff of low to moderate intensity.At the seasonal level, the highest sediment and phosphorus removal efficiency is observed in the summer seasons (47% for sediment and 29% for phosphorus), when the sediment and phosphorus loads and runoff are at their lowest, and the lowest in autumn (23% for sediment) and in winter (4% for phosphorus). The relationship between removal efficiency and loads to the CW is not that straightforward, as other seasonal differences, such as erosion patterns, vegetation development, also become important.The conclusion based on the results presented is that establishing CWs can be a good supplement to best management practice in erosion-prone catchments with sensitive recipients.

Sediment degradation experiments for a low gradient stream suggest the watershed’s connectivity regime exhibits control on stream biogeochemistry

Knowledge is lacking for sediment organic matter degradation and its influence on water quality for low gradient agriculturally impacted streams despite their importance for freshwater biogeochemical cycles and ecological restoration. We hypothesized degradation rates vary across sediment type and are a function of the connectivity regimes for low gradient systems. We carried out aerobic incubation experiments to assess oxidation and mineralization-nitrification rates and changes in stable isotopic ratios for sediment and dissolved organic matter and nitrate. Sediment originated from erosion across the watershed’s surface shows higher carbon oxidation rates (k = 3.9 × 10−3 d−1) and lower nitrogen mineralization-nitrification rates (k = 7.9 × 10−4 d−1) compared to sediment originated from the creek’s streambed that integrates algae and other autotrophic matter (k = 1.6 × 10−3 d−1 and k = 3.4 × 10−3 d−1). Differences are attributed to sediment transport of humified and plant matter during storms of high watershed connectivity and sediment transport of autochthonous sediment for low connectivity. Results support our hypothesis and suggest that the sediment connectivity regime of the watershed exhibits control on biogeochemical cycling of the stream network. Cumulatively, sediment degradation rates were one to two orders magnitude higher than previously assumed. Sediment rates reflect aerobic waters and place the organic matter as active and comparable to reported turnover of algae and fine sized leaf litter. Stable isotopic ratios of sediment change marginally for the two sediment types for carbon (ε = 0.4 ‰ and 1.3 ‰) and nitrogen (ε = 3.5 ‰ and 1.5 ‰). Dissolved organic nitrogen of stream water degraded similarly across all experiments (k = 1.8 × 10−2 d−1), and turnover rates were an order of magnitude higher than recent rates reported for lake water. Nitrate concentration in the solute increased by an average 35 % during experiments and the nitrogen stable isotopic ratio of nitrate decreased by over 1 ‰ showing the potential of sediment and dissolved organic matter degradation to influence nitrate flux and its isotopic signal.

The role of earthquakes and storms in the fluvial export of terrestrial organic carbon along the eastern margin of the Tibetan plateau: A biomarker perspective

Driven by earthquakes and intense rainfall, steep tectonically active mountains are hotspots of terrestrial organic carbon mobilization from soils, rocks, and vegetation by landslides into rivers. Subsequent delivery and fluvial mobilization of organic carbon from different sources can impact atmospheric CO2 concentrations across a range of timescales. Extreme landslide triggering events can provide insight on processes and rates of carbon export. Here we used suspended sediment collected from 2005 to 2012 at the upper Min Jiang, a main tributary of the Yangtze River on the eastern margin of the Tibetan Plateau, to compare the erosion of terrestrial organic carbon before and after the 2008 Wenchuan earthquake and a storm-derived debris flow event in 2005. To constrain the source of riverine particulate organic carbon (POC), we quantified lignin phenols and n-alkanoic acids in the suspended sediments, catchment soils and landslide deposits. We found that riverine POC had higher inputs of less-degraded, discrete organic matter at high suspended sediment loads, while the source of POC seemed stochastic at low suspended sediment concentrations. The debris flow in 2005 mobilized a large amount of POC, resulting in an export of lignin within a single day equivalent to a normal year. In comparison, the 2008 Wenchuan earthquake increased the flux of POC and particulate lignin, albeit with limited impact on POC sources in comparison to seasonal variations. Our results highlight the important role of episodic events in the fluvial export of terrestrial carbon.

Plateletcrit as a prognostic marker in Hodgkin lymphoma: A pilot study

Background/Aim: Hodgkin lymphoma (HL) is a lymphoproliferative malignancy associated with inflammation. Plateletcrit (PCT) is a mean platelet volume (MPV) and platelet count-derived marker that is useful for evaluating malignancies and inflammatory diseases. International Prognostic Score (IPS-7) and more recently, IPS-3, are two indices indicating the prognosis of patients; however, widespread and easy to interpret prognostic markers are still needed for HL evaluation. Very few studies evaluating the prognostic significance of platelet indices in HL have been published, so we aimed to show the relationship between PCT and other adverse prognostic factors in HL and evaluate whether PCT can be used as a prognostic marker in HL. Methods: After excluding patients with insufficient data, 75 patients diagnosed with HL and 150 healthy controls were retrospectively analyzed in this case-control study. Evaluation of relationship of PCT and adverse HL prognostic factors, such as age, gender, hemoglobin, leukocytes, lymphocytes (absolute value and percentage), albumin, Ann Arbor stage and B symptoms, IPS-3 and-7 prognostic scores and post-treatment relapse, and progression-free survival of the patients were studied. Results: Mean MPV values were significantly lower, mean platelet values were significantly higher inpatient group (all P<0.001). Patients with high sedimentation had significantly higher mean PCT than those without (P=0.031) and a moderately positive correlation between PCT and sedimentation were found (r=0.33, P<0.01). Mean PCT values after treatment significantly decreased compared to baseline levels (P<0.001). Conclusion: PCT may be useful as a prognostic marker in HL. Further studies were needed to evaluate the relationship between PCT and other prognostic factors, such as IPS-3 and -7.

New constraints on the closure of the Betic Seaway and the western Mediterranean palaeoclimate during the Messinian Salinity Crisis from the Campo Coy Basin (SE Spain)

The Campo Coy Basin (SE Spain) exposes >1 km of sedimentary succession with a variety of rocks including a thick evaporitic succession previously associated with the Messinian time. These evaporites were supposedly deposited in a restricted Mediterranean-Atlantic seaway connecting the Lorca and Guadix-Baza basins, although no chronological or geochemical data existed. Here we use palaeomagnetism together with vertebrate and foraminifera biostratigraphy to constrain the age of the Campo Coy succession between <9 Ma and 4.7 Ma. We use geochemistry (δ34S, δ18O and 87Sr/86Sr values) of the gypsum deposits to evaluate their marine or continental origin. In addition, we describe the underlying and overlying lithostratigraphic units to reconstruct the palaeogeographic evolution of this region. Our results show that the sediments were deposited in a continental environment, indicating that the Betic Seaway was already closed in this region during the late Tortonian and that the neighbouring marine basins of Guadix-Baza and Lorca were disconnected during that time. The δ34S, δ18O and 87Sr/86Sr values of the gypsum indicate recycling from the Triassic sulphates. Sedimentary facies of the evaporites point to an environment dominated by a saline lake with continental sabkha episodes developed during the driest periods. Well-defined and laterally continuous evaporitic cyclicity suggests an orbital forcing and high sedimentation rates preceding the Messinian Salinity Crisis (MSC). Alluvial deposits are contemporaneous with the MSC indicating a dry continental environment in this region during the Mediterranean restriction. Overlaying lacustrine carbonates are rich in small vertebrate fauna including African species that migrated to Europe during the MSC. These carbonates have low δ18O and δ13C values characteristic for freshwater input in an open lake just after the Zanclean flood, suggesting that a wet climate followed the MSC.

Dual Ion-Selective Membrane Deposited Ion-Sensitive Field-Effect Transistor Integrating a Whole Blood Processing Microchamber for In Situ Blood Ion Testing.

Blood ion testing is one of the methods that is commonly used for monitoring the immune status and providing physiological information for disease diagnosis. However, traditional blood ion sensing methods often require well-trained operators to process the whole blood sample and perform the measurements using bulky instruments, making real-time and continuous blood ion sensing at the bedside difficult. To address the above issues, we proposed a dual ion-selective membrane deposited ion-sensitive field-effect transistor (DISM-ISFET) sensor integrating a microchamber to enable on-chip serum extraction and in situ Na+/K+ ion sensing. As a proof of concept, we sequentially dispensed NaCl and KCl solutions at various concentrations on the DISM-ISFET to find out the highest ion sensitivity and selectivity. Next, we also confirm the high red blood cell sedimentation and serum purity using a microchamber. Finally, we evaluated the system performance using nine clinical whole blood samples and compared their Na+/K+ ion-sensing results with a commercial pocket ion meter. To sum up, our results showed that a DISM-ISFET system can successfully extract 200 μL serum from 500 μL whole blood sample and simultaneously achieve Na+/K+ ion sensing. All the sample processes and measurements can be finished within 10 min in a single chip. We envision this compact and easy-to-use system can be potentially used for various medical environments requiring real-time and continuous blood ion monitoring, such as in a hemodialysis room, operation room, and intensive care unit.

Anthropogenic impacts on tidal creek sedimentation since 1900.

Land cover and use around the margins of estuaries has shifted since 1950 at many sites in North America due to development pressures from higher population densities. Small coastal watersheds are ubiquitous along estuarine margins and most of this coastal land-cover change occurred in these tidal creek watersheds. A change in land cover could modify the contribution of sediments from tidal creek watersheds to downstream areas and affect estuarine habitats that rely on sediments to persist or are adversely impacted by sediment loading. The resilience of wetlands to accelerating relative sea-level rise depends, in part, on the supply of lithogenic sediment to support accretion and maintain elevation; however, subtidal habitats such as oyster reefs and seagrass beds are stressed under conditions of high turbidity and sedimentation. Here we compare sediment accumulation rates before and after 1950 using 210Pb in 12 tidal creeks across two distinct regions in North Carolina, one region of low relief tidal-creek watersheds where land cover change since 1959 was dominated by fluctuations in forest, silviculture, and agriculture, and another region of relatively high relief tidal-creek watersheds where land-use change was dominated by increasing suburban development. At eight of the creeks, mass accumulation rates (g cm-2 y-1) measured at the outlet of the creeks increased contemporaneously with the largest shift in land cover, within the resolution of the land-cover data set (~5-years). All but two creek sites experienced a doubling or more in sediment accumulation rates (cm yr-1) after 1950 and most sites experienced sediment accumulation rates that exceeded the rate of local relative sea-level rise, suggesting that there is an excess of sediment being delivered to these tidal creeks and that they may slowly be infilling. After 1950, land cover within one creek watershed changed little, as did mass accumulation rates at the coring location, and another creek coring site did not record an increase in mass accumulation rates at the creek outlet despite a massive increase in development in the watershed that included the construction of retention ponds. These abundant tidal-creek watersheds have little relief, area, and flow, but they are impacted by changes in land cover more, in terms of percent area, than their larger riverine counterparts, and down-stream areas are highly connected to their associated watersheds. This work expands the scientific understanding of connectivity between lower coastal plain watersheds and estuaries and provides important information for coastal zone managers seeking to balance development pressures and environmental protections.

Stroke and endocarditis: Reversing the point of view. A retrospective, cohort study

Study objectivesThe primary objective of our study is to assess the endocarditis prevalence in patients admitted to the emergency department (ED) for a primary diagnosis of acute stroke (AS). Secondary objectives are the identification of early markers of endocarditis in AS patients and the analysis of the short-term outcome of this population. MethodsIn this observational, retrospective, cohort study we enrolled consecutive adult patients with a primary diagnosis of AS admitted to the Stroke Unit or to the Neurological Intensive Care Unit of our hospital who were then discharged with a diagnosis of endocarditis. These patients were then compared with age and sex-matched controls with a diagnosis of AS and atrial fibrillation. ResultsEndocarditis prevalence in patients admitted to the Stroke Unit or Neurological Intensive Care Unit with a primary diagnosis of AS is 1.0% (95% confidence interval 0.61-1.55). Fever on ED admission, concomitant cancer, low hemoglobin, low lymphocyte levels, a high neutrophils count and erythrocyte sedimentation levels could early differentiate among AS patients, those with endocarditis from those with atrial fibrillation. A moderate-to-severe valvular regurgitation is strongly suggestive of endocarditis. The short term-outcome is markedly worse in endocarditis patients compared to patients with atrial fibrillation, in terms of in-hospital mortality and discharge disability. ConclusionsEndocarditis prevalence in patients admitted for a primary diagnosis of AS is low, but this etiology leads to a poor outcome. Some laboratory, clinical-epidemiological and echocardiographic parameters may help the physician to early recognize this condition and, consequently, to promptly start an antibiotic therapy.

Prediction of sediment wear of francis turbine with high head and high sediment content

Wear of runner blades is a common problem affecting the operational reliability of turbines with high head and high sediment content. In order to accurately predict the wear of the turbine runner blade, based on the solid-liquid two-phase flow equation and turbulence model, the full channel numerical simulation of the internal water and sediment flow was carried out, and the sediment volume distribution and sand water velocity on the turbine runner blade were obtained. Then, according to the digital simulation results and the operating parameters of the turbine runner, the sediment wear test scheme for the turbine blade material specimen is designed, and the sediment wear test is carried out on the runner material. According to the test results, the sediment wear curve of runner blade material is obtained and applied to numerical simulation, and the main position and wear degree of turbine blade sediment erosion are predicted. The inspection results of the runner blade wear after the unit has operated for a flood season show that obvious wear can be seen at the outlet edge of the lower band of the runner blade, and the wear position and wear amount are basically consistent with the simulation values. The study is of great importance for predicting the wear of turbine runner blades with high drop height and high sediment content, and for turbine maintenance under complex conditions.

Deposition of cenomanian – Turonian organic-rich units on the mid-Norwegian margin: Controlling factors and regional implications

On the mid-Norwegian margin, extensive rifting and subsequent deposition of thick Cretaceous and Cenozoic sediments have buried the traditional Upper Jurassic organic-rich shales too deep. Consequently, these organic-rich shales are overmature and spent in the deep basins on the mid-Norwegian margin. The absence of well-control, variable seismic quality and in particularly, the great burial depth, makes it difficult to identify alternative Upper Jurassic and Lower Cretaceous organic-rich units. By combining high-resolution 2D seismic data, well logs, and Rock-Eval data, this study documents the presence of alternative organic-rich units in the Cretaceous succession on the Halten Terrace and the Vøring Basin. Multiple seismic horizons which correspond to regional flooding surfaces and define a series of seismic sequences have been mapped across the study area. The regionally extensive upper Cenomanian horizon is associated with wireline log signals and Rock-Eval parameters which imply the presence of a potential source rock unit. Source rock evaluation indicate that this unit contains mainly kerogen Type III on the Halten Terrace, suggesting an organofacies with significant contribution from terrestrial sources. In the Vøring Basin, the unit is sparsely drilled but appears to be mature, thus displaying a relatively limited potential. One well from the Vigrid Syncline demonstrate somewhat higher potential, with Rock-Eval data indicating a kerogen Type II composition. As such, more prolific units seems to exist in the Vøring Basin, albeit exhibiting a patchy distribution. We speculate that the deposition and preservation of this upper Cenomanian organic-rich unit record the development of an extended oxygen minimum zone attributable to increased primary production and sluggish water circulation, linked to the global Oceanic Anoxic Event 2 (OAE 2). However, local physiographic conditions, such as high sedimentation rates, erosion by gravity flows and periodically oxygenated conditions hindered preservation of a significant quantities of organic matter, thus limiting the thickness and quality of the upper Cenomanian organic-rich unit on the mid-Norwegian margin.

Co-valorization of sediments incorporating high and low organic matter with alkali-activated GGBS and hydraulic binder for use in road construction

This study investigates the valorization of dredged sediments containing high and low organic matter (OM) content with alkali-activated ground granulated blast furnace slag (GGBS) and conventional hydraulic binders (HB). The objective is to develop a sustainable material with the necessary qualities for road construction. Research is conducted on dredged sediments from the French port of Cherbourg (CHER-ALL sediments) and the dam in the Maurienne Valley of France (MOR-ALL sediments), with high and low levels of OM content, respectively. After the determination of physico-chemical and mineralogical characteristics, high organic CHER-ALL sediments were first valorized using conventional HB and then co-valorized using low carbon footprint alkaline activated byproducts (AAB). The alkali activation of the byproduct (GGBS) was performed with a chemical activator named NeoliX. AAB and HB were utilized to treat the dredged sediments to compare their mechanical performances as well as environmental impacts. In terms of mechanical performance, the obtained results revealed that AAB outperformed traditional HB, and concerning the environmental impacts, byproducts have no carbon footprint except for their transportation. As a consequence, AAB has also been utilized to co-valorize the sediments from the Maurienne dam (MOR-ALL sediments) as well. AAB co-valorization of these two sediments (CHER-ALL and MOR-ALL) with varying degrees of OM content facilitates an understanding of the effects of OM concentration on mechanical properties. The high OM content of the CHER-ALL sediment (>17%), regardless of the proposed mixing with traditional HB, proved to impede the valorization, since the 28-day UCS did not exceed 1 MPa. The CBR as well as ultimate tensile strength (UTS) testing confirms the reported trends from the UCS experiments. In addition, the presence of a high OM concentration significantly decreased the mechanical properties of dredging sediments co-valorized with AAB. However, depending on the mass percentage of sediment (wt%) in the mix design, it was achievable to attain the required minimum strength value of 1 MPa with 30% and 70% of CHER-ALL and MOR-ALL sediments, respectively. Even if the OM content of sediments is high, alkaline activation can be employed to co-valorize them, as demonstrated by these encouraging results. The quantity of sediment to be co-valorized is depend upon their OM content.

Fluvial responses to late Holocene hydroclimate variability in the midcontinental United States

Long-term relationships between mean-state climatic conditions and flood frequencies in the midcontinental United States (US) are not well established because instrumental records of fluvial processes are limited to the current warm period (CWP; the last ca. 150 years) and continuous paleo-flood records are exceedingly rare. Here, we investigate climate-flood relationships in the midcontinental US by reconstructing flood frequencies at Half Moon Pond, a 1600-year-old oxbow lake on the lower White River, Indiana (watershed = ca, 29,000 km2). We used sediment accumulation rates and clastic fluxes constrained by high-resolution radiocarbon (14C) dating. Frequent flooding, as indicated by high sedimentation rates and clastic fluxes to Half Moon Pond, occurred leading up to and during the Medieval Climate Anomaly (MCA; 950–1250 CE) when paleoclimate records suggest the predominance of ocean-atmosphere mean states resembling the negative phases of the Pacific Decadal Oscillation (-PDO-like) and Pacific North American Mode (-PNA-like). Reductions in sedimentation rates and clastic fluxes, indicating reduced flooding, subsequently occurred during the transition out of the MCA and into the Little Ice Age (LIA; 1250–1830 CE) as ocean-atmosphere conditions shifted to + PDO-like and +PNA-like mean states. Sedimentation rates and clastic fluxes increased again after ca. 1800 CE, indicating increased flooding during the CWP as ocean-atmosphere conditions returned to -PDO-like and -PNA-like mean states. The White River trends were notably antiphased with sedimentation-rate-based flood frequencies for the lower Ohio River (500,000 km2 watershed) prior to 1830 CE. This antiphased relationship is consistent with flooding in moderate to small watersheds in the Midwest being sensitive to the occurrence of rainstorm events, which were more frequent leading up to and during the MCA, and flooding in large watersheds being more sensitive to large spring melts associated with extensive snowpacks, which characterized the LIA. That both the White and Ohio rivers experienced their most frequent flooding during the CWP suggests deforestation and changing land use practices increased flooding on Midwestern watersheds across scales despite a current climatic mean state that in the past only resulted in increased flooding on moderate to small watersheds. Continued increased in midcontinental rainfall are therefore likely to enhance the occurrence of floods in Midwestern watersheds across different geographic scales.

Effects of sluice gate operation on sediment flushing in Bekasi weir using a 1D numerical model

Sedimentation upstream of a weir is a common phenomenon, especially for a river with high sedimentation. In the long term, this can lead to problems since the discharge capacity will decrease due to the rise of the riverbed, as experienced in Bekasi Weir, West Java, Indonesia. The upstream accumulated sediments increased up to 1.5 m from its original riverbed in a decade. One of the easiest ways to overcome this issue is to return the riverbed elevation to its actual elevation by manual excavation or sediment flushing using a sluice gate. This paper discusses the effects of operating three sluice gates of the Bekasi Weir for flushing the deposited sediments. The analysis was carried out through 1D modeling using MIKE-11 software to analyze the morphological effects after flushing the sediments with variations of sluice gate opening scenarios. Finally, it was found that without any manual excavation, the flushing method with one fully-opened gate was the best solution by giving a significant upstream bed degradation of up to 1 m, reducing the upstream flood level, and maintaining the upstream-downstream freeboard. The solution could be more effective when combined with river normalization.

Marine animal forests in turbid environments are overlooked seascapes in urban areas

Marginal reefs can provide meaningful information about the structure and dynamics of ecosystems under suboptimal environmental conditions. In addition to their different characteristics, these environments can also occur in urbanized areas. In this note, we characterize marine animal forests (MAFs) on turbid-zone reefs on an urban coast in the equatorial southwestern Atlantic. Overall, the sandstone ferruginous reefs (6-10 m depth) exhibited a flat topography and gentle slope (1-2 m above the seabed). Benthic cover is composed mainly of sponge gardens and ascidians. In addition, we found a low-relief coral carpet with only one massive reef-building coral (Siderastrea stellata) and Zoantharia. The ascidians and sponges had a higher diversity (at least 15 species) than the cnidarians (two species) in these forests. The main animals forming this seascape are weedy and stress-tolerant species adapted to challenging environmental conditions, such as swell waves, mesotidal regimes, moderate turbidity waters, and periodic burial. In this regard, these conditions and human impacts have shaped a unique MAF. Remarkably, the studied formations seem similar to high-latitude marginal reefs or low-latitude reefs under the influence of upwelling, which sustains soft corals and non-framework building coral communities along with sponges and ascidians. In particular, the shallow MAFs along the semi-arid coast of Brazil seem to lack some of the characteristics of low-latitude reefs under high sedimentation, whose structure was described as coral rubble within sedimentary matrices. This suggests that factors other than periodic burials and low light availability affected these MAFs. These overlooked forests are widespread in this area and have been neglected in studies, despite their richness (> 31 taxa) and valuable ecosystem goods and services. In the context of urbanized areas subject to climate change and pollution impacts, jetties, and dredging activities, it is necessary to consider these lush forests in impact assessments and conservation policies.

Application of Deep-bed Denitrification Filter in Sewage Treatment

The combined process of A2/O oxidation ditch, high efficiency sedimentation tank and denitrification deep bed filter was adopted in Sewage Treatment Plant of Hefei City to treat municipal domestic sewage. The effluent quality could meet the discharge limit of major water pollutants in urban sewage treatment plants and industrial industries of Chaohu Lake Basin (DB34/2710-2016). In addition to the parameters of design and operation, the effect of SS and deep denitrification was summarized in detail in this paper. The results showed that the combined process SS and denitrification effect was removed very well. The operational results demonstrated SS removal efficiency 74.3%,TN removal efficiency (92.3％) in the biosystem ,in which 80.0％ and 12.3％ of TN in influent were removed in the pre-denitrif ication in oxidation ditch and post-denitrification in deep bed denitrification filter, respectively. The deep bed denitrification filter could be used as the safeguard for effluent TN with the addition of external carbon source to ensure the efficiency of TN less than 5 mg/L.

Disease patterns among Saudi children undergoing colonoscopy for lower gastrointestinal bleeding: Single tertiary care center experience.

: The yield of colonoscopy in cases presenting with lower gastrointestinal bleeding (LGIB) in previously published studies varies according to several factors, including endoscopic skills, histopathological experience, and pattern of colonic pathology in different countries. The local literature is limited to a single small 20-year-old study. Our objective was to provide updated data on the diagnostic yield of colonoscopy in Saudi children with LGIB in Saudi Arabia. : This was a retrospective analysis of pediatric patients (0-14 years of age) who underwent colonoscopy for LGIB at the King Fahad Medical City (KFMC), from 2008 to 2018. LGIB was defined as fresh or dark blood per rectum. : During the study period, 175 children underwent colonoscopy for LGIB (99 males, mean age 7.05 ± 3.81 years), which constituted 53.5% of indications for colonoscopy procedures (n = 327) in our center. The terminal ileum was intubated in 81% of the procedures. Overall, inflammatory bowel disease (IBD) was the most commonly identified cause of LGIB (32% ) followed by colonic lymphonodular hyperplasia (CLNH) in 17% and juvenile polyp and rectal mucosal prolapse syndrome (RMPS), 11% each. On sub-analysis, cow's milk protein allergy (CMPA) and CLNH were the most common causes in infants and toddlers, 35% each; IBD (26.5%) and polyps (22.4%) in young children (2-6 years), and IBD (36%), CLNH (14.9%) and RMPS (14%) in older children (6-14 years). In comparing the IBD to the non-IBD group, IBD patients were older (mean 8.37 vs. 6.46 years, P = 0.002) and more likely to have diarrhea, weight loss, high erythrocyte sedimentation rate, anemia, and hypoalbuminemia (odds ratio 24, 11, 10.7, 6.5, and 4, respectively). Colonoscopy had a sensitivity of 97%, specificity of 100%, positive predictive value of 100%, negative predictive value of 81.4%, and accuracy of 97% in diagnosing LGIB. : Colonoscopy is an effective diagnostic tool in children with LGIB with a high diagnostic yield. Besides IBD, CLNH and RMPS are two other important pathologic entities that need to be considered in a child with LGIB.

The effect of sediment density parameter values on the debris flow velocity parameters

Debris flow is a phenomenon where the material from the eruption is carried away by the flow of water due to rain in the upstream area of the river and usually crashes into watersheds around the volcano. The potential for large debris flows can be caused by high rainfall and sediment deposits that occur during debris flows. Rainfall and sediment carried by water flow can affect the volume and velocity of debris flows. A debris flow simulation was carried out to anticipate casualties and damage using SIMLAR V2.1 by modifying rain intensity and the density of sediment carried by the debris flow. Based on the result, we can obtain the results of the velocity, volume, and area affected by the debris flow. The flow velocity values obtained for testing with rainfall intensity of 162 mm with a density of sediment 1370 kg/m3, 2340 kg/m3, 2635 kg/m3, and 2820 kg/m3, respectively, were 2.72 m/s, 2.16 m/s, 2.50 m/s, and 2.57 m/s. The volume values with the same intensity and density of sediment are 186,381 m3, 311,116 m3, 274,030 m3, and 294,987 m3. Based on the test results, it can be concluded that sediment density significantly affects the velocity and volume of the debris flow. Where sediment density is inversely proportional to the flow velocity, the higher the sediment density, the slower the flow velocity, while the volume is directly proportional to the sediment density. The higher the density of the sediment, the higher the volume.

Atypical clinical presentation of rheumatoid arthritis

Introduction. Rheumatoid arthritis is a systemic autoimmune disease with inflammation of the joints as its hallmark. Extra-articular manifestations affect nearly half of the patients either at the onset of disease or later during the disease course. Case outline. A 43-year-old man complained of chest pain, dry cough, and fatigue. Diagnosis of pericarditis was made based on echocardiography findings. Due to worsening of respiratory symptoms, he was admitted to the hospital. Initial diagnostic workup revealed elevated concentrations of acute phase reactants, pericardial effusion, and bilateral pulmonary nodules. Pathohistological analysis of lung nodules ruled out malignancy and tuberculosis. He was treated with colchicine, which led to a regression of a pericardial effusion. Afterwards, due to arthritis of the right wrist, high erythrocyte sedimentation rate, and C-reactive protein, positive immunoserology and bone erosion at the distal ulna diagnosis of seropositive rheumatoid arthritis was established. He was treated with antimalarial, methotrexate, and glucocorticoids until he suffered from COVID-19 pneumonia, which triggered arthritis flare. Owing to the loss of efficiency of combination therapy with methotrexate and glucocorticoid, baricitinib was added to the treatment. Low disease activity was achieved after three months of administering baricitinib and methotrexate, and no adverse events occurred during 20-month-long therapy. Conclusion. Every patient with pericarditis of unknown etiology should be diagnostically evaluated in term of connective tissue disease including rheumatoid arthritis, because the initial clinical presentation in some group of patients could lack characteristic synovitis.