Minimum Elevation Research Articles

MONITORAMENTO DE RECURSOS HIDRÍCOS POR ALTIMETRIA ESPACIAL

Although most of the space missions discussed here have not been primarily dedicated to hydrology, 31 years of spatial altimetry have provided complementary data that can be used to create hydrological products for watersheds, such as time series water levels, estimates of river flows, longitudinal riverbed altitude profiles, minimum and maximum elevations, or leveling of stations in situ. The raw data still suffer from uncertainties of several decimeters. Today, altimetry techniques are evolving rapidly. One direction is the change of the radar band, from Ku to Ka. Another change is the replacement of the current LR Mode with SAR or Interferometry modes. Both evolutions tend to drastically decrease the imaged range, reducing both the contamination of the echo by the environment of the water body, and improving the vertical accuracy. Finally, as of 2015, the research missions were replaced by operational ones, making the longevity of the sampling sites more certain. All the aforementioned technical evolutions have been grouped together in the SWOT mission, a Ka-band interferometric altimeter, the first satellite mission actually dedicated to providing full coverage of continental waters, launched in December 2022.

Joint satellite platform and constellation sizing for instantaneous beam-hopping in 5G/6G Non-Terrestrial Networks

Existing research on resource allocation in satellite networks incorporating beam-hopping (BH) focuses predominantly on the performance analysis of diverse algorithms and techniques. However, studies evaluating the architectural and economic impacts of implemented BH-based technical solutions have not yet been addressed. Aiming to close this gap, this contribution quantifies the impact of BH and orbital parameters on the satellite platform and constellation size, considering specific traffic demand and service time indicators. The paper proposes a low complexity, instantaneous demand-based BH resource allocation technique, and presents a comprehensive analysis of LEO and VLEO scenarios using small platforms, lying on 5G/6G Non-Terrestrial Network (NTN) specifications. Given a joint set of traffic demand and time-to-serve indicators, and based on a feasible multibeam on-board antenna architecture, the paper compares the RF transmit power requirements in fixed and variable grid LEO schemes, and in VLEO with different minimum elevation angles, to assess the feasibility of these orbits. For a fixed minimum elevation and number of users, the RF transmit power and satellite platform requirements are significantly reduced when transitioning into lower altitudes with narrower satellite coverage areas. The relevant trade-off between the satellite platform and the size of the constellation required for global coverage is presented, to fulfill a set of traffic demand and time to serve indicators: approximately, 1156 3U satellites are required for VLEO constellation and 182 12U satellites for LEO. Once platform and constellation sizing trade-off is quantified, the paper estimates the economic costs for each of the deployments, showing a total cost of almost the double for the presented VLEO constellation compared to the LEO one. The article aims to provide system engineers and satellite operators with crucial information for satellite system design, dimensioning and cost assessment.

Regional analysis of specific suspended sediment loads in northern Iran using multivariate statistical techniques

ABSTRACT Predicting suspended sediment loads in areas without detailed measurements, or with only short-term records, is crucial for the sustainable management of water resources. This study aimed to establish the relationships between specific suspended sediment loads and the characteristics of 23 sub-basins within the Haraz-Neka River basin, in Iran, to create regional models to estimate the sediment loads. To achieve this, several analytical methods were used, including cluster analysis, principal component analysis, principal component and classification analysis, and general linear modelling. Among these, the principal component analysis regression model was the most effective for estimating suspended sediment loads in the clusters. The principal component and classification analysis revealed that the best predictor was the first principal component, which strongly correlated with the minimum and mean elevation of the sub-basins. The general linear model regression showed the best overall performance for estimating regional suspended sediment loads in the study area.

Re-evaluating Marine Isotope Stage 5a paleo-sea-level trends from across the Florida Keys reef tract

Unraveling how Global Mean Sea Level (GMSL) fluctuated during past warm periods can improve our understanding of linkages between sea-level fluctuations, orbital forcing, and ice-sheet dynamics. Current estimates of GMSL for Marine Isotope Stages (MIS) 5a and 5c — two warm intervals following the relatively well-documented MIS 5e — contain meters of uncertainty and fewer data due to several challenges. These challenges include concealment of datable in-situ coral facies by MIS 1 deposits and inaccessibility due to submergence by modern sea level. We present a comprehensive dataset based on U–Th dating and stratigraphic correlation of 23 cores totaling over 170 m of recovered coral-reef deposits across the tectonically stable Florida Keys Reef Tract (FKRT). Following detailed facies descriptions, 34 in-situ, minimally altered aragonitic coral samples (≤2.7% calcite) below the Holocene-Pleistocene boundary were targeted for U–Th geochronology. Fourteen closed-system coral U–Th ages from MIS 5a include the commonly used sea-level indicator Acropora palmata, but also the massive coral taxa Pseudodiploria strigosa, Siderastrea siderea, Orbicella spp., and Porites astreoides. Dating yielded ages in the range of 88–81 ka (average 2σ uncertainty of less than 200 years). These ages suggest MIS 5a reef initiation at ∼88 ka BP, a peak near 83 ka with minimum elevations between −6.0 ± 0.5 and −5.6 ± 0.5 m MSL (2σ uncertainty and subsidence-corrected), and reef termination and sea-level fall by ∼81 ka BP. Notably, the range of peak MIS 5a relative sea-level estimates of −6.5 to −5.1 m MSL are more than 2 m shallower (higher) than previous estimates of −11 to −9 m. Our higher resolution regional sea-level reconstruction across four subregions of the Florida Keys reef tract aligns with changes in July insolation at 65° N: a trend that most other records, such as deep-sea sediments, do not have the accuracy and precision to resolve. Three massive coral samples from MIS 5c, consisting of Pseudodiploria clivosa, and Orbicella spp., yielded ages in the range of 104 to 99 ka (average 2σ uncertainty less than 200 years); however, because only one sample met the closed-system criteria, our ability to estimate MIS 5c sea level is relatively limited. More empirical estimates of sea-level from the MIS 5a and MIS 5c intervals based on numerical dating of reliable local sea-level constraints are critical for GMSL calculations and relating changes in sea-level amplitude and timing to global ice volume modeling and glacio-isostatic effects, all of which can improve predictions of future sea-level changes in coastal regions.

Disentangling the drivers of urban bird diversity in the non-breeding season: A general synthesis.

Current knowledge about the impacts of urbanisation on bird assemblages is based on evidence from studies partly or wholly undertaken in the breeding season. In comparison, the non-breeding season remains little studied, despite the fact that winter conditions at higher latitudes are changing more rapidly than other seasons. During the non-breeding season, cities may attract or retain bird species because they offer milder conditions or better feeding opportunities than surrounding habitats. However, the range of climatic, ecological and anthropogenic mechanisms shaping different facets of urban bird diversity in the non-breeding season are poorly understood. We explored these mechanisms using structural equation modelling to assess how urbanisation affects the taxonomic, phylogenetic and functional diversity of avian assemblages sampled worldwide in the non-breeding season. We found that minimum temperature, elevation, urban area and city age played a critical role in determining taxonomic diversity while a range of factors-including productivity, precipitation, elevation, distance to coasts and rivers, socio-economic (as a proxy of human facilitation) and road density-each contributed to patterns of phylogenetic and functional diversity. The structure and function of urban bird assemblages appear to be predominantly shaped by temperature, productivity and city age, with effects of these factors differing across seasons. Our results underline the importance of considering multiple hypotheses, including seasonal effects, when evaluating the impacts of urbanisation on biodiversity.

Functional ecology and evolution of terrestrial and epiphytic species of Rhododendron section Schistanthe (Ericaceae)

Epiphytes are often characterized by small size, specifically adapted to a relatively dry and nutrient-poor habitat. However, this epiphyte syndrome is derived from studies on species-rich and habitat-dominating groups such as orchids and bromeliads. To better understand general trait syndromes of epiphytes, it is important to analyze plant groups that are more transitional in the evolution of epiphytism e.g., the Australasian vireyas (Rhododendron sect. Schistanthe; Ericaceae). Here, we studied the morphology, ecophysiology, and anatomy of 44 species of Rhododendron section Schistanthe from living collections and obtained data for 288 species related to their "life form" (holoepiphytes [= obligatory epiphytes], facultative epiphytes and terrestrial congeners) from the literature. For phylogeny and time-calibrated tree, we used the nuclear ITS (Internal Transcribed Spacers) region. Using different statistics and phylogenetic comparative methods, our results support the hypothesis that holoepiphytic vireyas are smaller in size than the terrestrial ones. Terrestrial vireyas are found at higher minimum and maximum elevation than either facultative or holoepiphytic congeners. We demonstrate that the diversification of tropical Rhododendron is not related to the evolution of the epiphytic life form. Regarding the evolution of traits that are important for water economy, holoepiphytic vireyas do not differ much from their terrestrial relatives indicating that evolutionary steps for specialization towards an holoepiphytic habit are in their initial stages in Rhododendron. Given the large species diversity of the group conclusions based on the subset used here must be considered preliminary. However, our results provide the basis for more detailed future studies.

Machine learning modeling of base flow generation potential: A case study of the combined application of BWM and Fallback bargaining algorithm

The study of base flow is essential for sustainable water management. By understanding the dynamics of base flow, policymakers can make informed decisions to ensure the long-term health and availability of water resources. This study was conducted with the aim of modeling the spatial changes of Base Flow Generation Potential (BFGP) using integrated Machine Learning Algorithms (MLAs) including Decision Tree Regression (DTR), K-Nearest Neighbors (KNN), Naïve Bayes (NB), Random Forest (RF), Simple Linear Regression (SLR), Support Vector Machine (SVM) and Support Vector Regression (SVR) and optimal Multi-Criteria Decision Making (MCDM) methods including Best-Worst Method (BWM) and Fallback bargaining in the Cheshmeh-Kileh watershed, Iran. BFGP conditioning factors were selected for the Sub-Watershed (SW) and weighed using MCDM (BWM and Fallback bargaining algorithm) methods. BFGP maps of five classes were generated and analyzed. MCDM methods were also integrated with ML algorithms for optimum performance evaluation of the integrated unit. Based on the results, in the integrated model of BWM and Fallback bargaining algorithm with ML algorithms, SVR and RF algorithms was selected as the optimal model, respectively. In BWM in the Sehezar River, the upstream had the highest BFGP. The pattern of spatial changes based on the Fallback bargaining algorithm in the upstream of Sehezar River was similar to BWM. The combined approach of RF-GTA with the factors of minimum temperature (Tn), NDSI and elevation showed the highest correlation. It was observed that that the Fallback bargaining algorithm and BWM of the MCDM exhibited similarity in output of regarding the spatial change patterns of the BFGP. Also, Fallback bargaining exhibited a 67% similarity with the integrated RF-GTA in BFGP prioritization of the SWs, while BWM performed poorly. This suggests that the Fallback bargaining algorithm was more effective than BWM of the MCDM methods for SWs BFGP prioritization. The general summary indicated that the combined use of MCDM and MLAs were valuable tools in BF studies and helped in better understanding the complex hydrological processes. The findings of our research may be of help to Iran Water Resources Research Company using hydrological data arising from base flow studies to support their analysis. In conclusion, understanding the BF characteristics of SWs allows watershed managers to effectively prioritize conservation and restoration efforts aimed at protecting and enhancing the natural flow regime.

A Science and Community-Driven Approach to Illustrating Urban Adaptation to Coastal Flooding to Inform Management Plans

Academic research plays a pivotal role in illustrating and testing potential future adaptation strategies to sea level rise in low-lying coastal communities and enhances local municipalities’ adaptation plans. In Waikīkī, Hawai‘i, the built environment is increasingly impacted by flooding from multiple drivers: sea level rise-induced direct marine inundation, storm-drain backflow, and groundwater inundation (GWI), compounded by high-wave runup, extreme tides, heavy rainfall, and a shallow groundwater table. Given Waikīkī’s economic and cultural importance, in-place accommodation of flooding is desired, yet implementation plans have not been developed. By combining current scientific research, urban design visualizations, and community feedback, the interdisciplinary research team advanced intentional communication between the many parties seeking increased flood resilience through the end of the 21st century. Site-specific architectural renderings were a key tool to prompt structured community input on the coordination, prioritization, policy, and feasibility of adaptation measures for buildings, utilities, transportation, and open space. Public outreach reports document that the majority of participants thought all adaptation strategies presented were applicable, especially relocating critical equipment in buildings and streets. Proposed methods to develop sea level rise-adjusted minimum building elevation requirements may inform local municipalities’ future codes to minimize coastal property damage. The multi-year iterative process fostered growing participation in hosted and invited events, further improving the publicly distributed research products.

Machine learning and phylogenetic models identify predictors of genetic variation in Neotropical amphibians

AbstractAimIntraspecific genetic variation is key for adaptation and survival in changing environments and is known to be influenced by many factors, including population size, dispersal and life‐history traits. We investigated genetic variation within Neotropical amphibian species to provide insights into how natural history traits, phylogenetic relatedness, climatic and geographic characteristics can explain intraspecific genetic diversity.LocationNeotropics.TaxonAmphibians.MethodsWe assembled data sets using open‐access databases for natural history traits, genetic sequences, phylogenetic trees, climatic and geographic data. For each species, we calculated overall nucleotide diversity (π) and tested for isolation by distance (IBD) and isolation by environment (IBE). We then identified predictors of π, IBD and IBE using random forest (RF) regression or RF classification. We also fitted phylogenetic generalized linear mixed models (PGLMMs) to predict π, IBD and IBE.ResultsWe compiled 4052 mitochondrial DNA sequences from 256 amphibian species (230 frogs and 26 salamanders), georeferencing 2477 sequences from 176 species that were not linked to occurrence data. RF regressions and PGLMMs were congruent in identifying range size and precipitation (σ) as the most important predictors of π, influencing it positively. RF classification and PGLMMs identified minimum elevation as an important predictor of IBD; most species without IBD tended to occur at higher elevations. Maximum latitude and precipitation (σ) were the best predictors of IBE, and most species without IBE occur at lower latitudes and in areas with more variable precipitation.Main ConclusionsThis study identified predictors of genetic variation in Neotropical amphibians using both machine learning and phylogenetic methods. This approach was valuable to determine which predictors were congruent between methods. We found that species with small ranges or living in zones with less variable precipitation tended to have low genetic diversity. We also showed that Western Mesoamerica, Andes and Atlantic Forest biogeographic units harbour high diversity across many species that should be prioritized for protection. These results could play a key role in the development of conservation strategies for Neotropical amphibians.

Inundation and nutrient assessment of farmed prairie potholes during a cropping season with high precipitation

AbstractEnclosed topographical depressions that retain water intermittently are abundant across the prairie pothole region of the United States. These depressional wetlands (potholes) are located at local minimum elevations with small contributing micro‐watersheds. These features are often located in areas where the primary land use is row crop agriculture; thus subsurface tile drainage has been implemented to improve crop production and field accessibility. However, even with drainage improvements, farmed potholes still tend to retain water during high precipitation periods. This study monitored 10 farmed potholes in 2018, a year with 32% more precipitation than the 30‐year average. Potholes were inundated between 12% and 81% of the monitored growing season; the highest inundation percentage occurred in a pothole without surface intakes. Nutrient concentrations in 2018 were lower on average than previously reported for the same potholes, possibly due to higher precipitation and less fertilizer applied because most of the potholes were in soybeans rather than corn. Total nitrogen and nitrate‐N median concentrations were 16.71 and 14.82 mg N L−1 lower (p‐value < 0.0001) during the early season (May 15–July 7) than concentrations in 2016–2017. Total phosphorus and dissolved reactive P median concentrations, conversely, were slightly but significantly lower during the late season (July 8–November 1) with 0.15 and 0.13 mg P L−1 difference (p‐value < 0.01), respectively. Observed DRP concentrations increased by 63% during multiday inundation periods. Our monitoring results suggest during seasons of heavy precipitation, farmed potholes might act as hotspots, contributing elevated levels of P to downstream waters.

Longitudinal changes in renal function in patients with chronic hepatitis B on antiviral treatment.

Patients with chronic hepatitis B (CHB) on nucleos(t)ide analogues (NUCs) often experience renal function decline. Conflicting results regarding the impact of NUC use and renal function have recently been reported. To examine longitudinal changes in renal function according to the NUC treatment type compared with untreated patients METHODS: From 2014 to 2022, we retrospectively analysed 10,642 patients with CHB. The primary outcome was chronic kidney disease (CKD) progression, which was defined as a minimum one-stage elevation. We applied propensity score (PS) matching for outcome comparisons. In the PS-matched cohort of 1996 pairs, the NUC-treated group (7.6/100 person-years [PYs]) had a significantly higher CKD progression risk than the untreated group (4.4/100 PYs), with a hazard ratio (HR) of 1.70 (p < 0.001). The tenofovir disoproxil fumarate (TDF)-treated group (7.9/100 PYs) showed a 1.76-fold increased CKD progression risk compared with the untreated group (4.5/100 PYs) in the PS-matched cohort (p < 0.001). Both the entecavir- and tenofovir alafenamide (TAF)-treated groups showed CKD progression risks comparable to those of the untreated group in the PS-matched cohorts of 755 and 426 pairs, respectively (p = 0.132 and p = 0.120, respectively). No significant CKD progression risk was found between the entecavir- (6.0/100 PYs) and TAF-treated (5.2/100 PYs) groups in the PS-matched cohort of 510 pairs (p = 0.118). NUC-treated patients, especially those on TDF, faced a higher CKD progression risk than untreated patients. Entecavir- and TAF-treated patients had comparable CKD progression risks to untreated patients. No difference was observed between entecavir and TAF in the risk of CKD progression.

Prediction of left ventricular thrombus after STEMI based on readily available clinical, echocardiographic and ECG variables

Abstract Background Left ventricular thrombus (LVTh) is an uncommon yet serious complication after ST-segment elevation myocardial infarction (STEMI). LVTh can be accurately detected in late gadolinium enhancement (LGE) sequences in cardiac magnetic resonance (CMR). However, selection of patients who should undergo this imaging technique for LVTh detection is not defined yet. Purpose We aim to stratify the risk of LVTh occurrence after STEMI by clinical, echocardiographic and ECG variables during admission and help select patients who should undergo CMR for LVTh detection. Methods Our registry comprised reperfused STEMI patients who underwent early (1-week) and late (6-month) CMR for clinical indication. LGE sequences were used to analyze the presence of LVTh. Baseline clinical characteristics were recorded. Echocardiography (Echo) was performed before discharge and left ventricular (LV) ejection fraction (LVEF, in %), LV end-diastolic and end-systolic diameters (in mm), tricuspid annular plane systolic excursion (TAPSE, in mm), E and A waves velocities (in m/s) and left auricular antero-posterior diameter (in mm) were measured. ECG during admission were analyzed and maximum and minimum ST-segment elevation, resolution of ST-segment (in %) and the number of leads with Q wave and ST-segment elevation &amp;gt;1mm (Q-STE) were recorded. Univariate and multivariate comparisons were performed to check for an association with LVTh in the first 6 months after STEMI (by CMR). A p&amp;lt;0.05 was considered statistically significant. Results The final cohort comprised 377 STEMI patients (mean age 58.51±11.64 years, 82% male). LVTh was detected in 29 (7.7%) patients by CMR during the first 6 months after STEMI. Predictors of LVTh on multivariate analysis were anterior infarction (HR 4.57 [1.28-16.29], p=0.02), Echo-LVEF (HR 0.97 [0.93-0.99] per %, p=0.04) and Q-STE (HR 1.33 [1.06-1.67] per lead, p=0.01). Echo-LVEF (best cut-off: ≤48%) and Q-STE (best cut-off: &amp;gt;3 leads) were dichotomized and several risk categories for LVTh were defined. In patients with zero or one risk factor the prevalence of LVTh ranged from 1.6% to 5.2% (if anterior infarction and no other risk factors). Patients with anterior infarction and any other risk factor had a 14.3% prevalence of LVTh. However, the highest prevalence was found in patients with concomitantly anterior infarction, Echo-LVEF ≤48% and Q-STE in &amp;gt;3 leads - in this subgroup (n=34, 9% of the cohort) LVTh was found in 26.5% of patients. Conclusions Left ventricular thrombus occurrence in the first 6 months after STEMI can be predicted by readily available clinical (anterior infarction), echocardiographic (LVEF) and ECG (Q-STE) variables before discharge. More than a quarter of patients with anterior infarction, Echo-LVEF≤48% and Q-STE in &amp;gt;3 leads depict LVTh. This could help select patients who should undergo CMR after infarction for LVTh detection.Central Figure.

Effects of Patch Density and Incoming Sediment on Flow Characteristics and Bed Morphology

This study focuses on the effects of vegetation patch density, bed condition, and incoming sediment on flow structure and bed morphology within and around a patch. The variation in upstream adjustment velocity is not well defined for low-density vegetation patches but decreases with increasing patch density in high-density patches. The length of the upstream adjustment region is greater for high-density vegetation. Incoming sediment causes a reduction in both the steady wake velocity and the length of the steady wake at a low density. The length of the recovery region increases with density when vegetation is sparse, but remains constant in a dense patch. Additionally, the length of the recovery region decreases due to incoming sediment. Turbulent kinetic energy is not affected by the bedform and incoming sediment when reaching its first peak. However, the second maximum of the turbulent kinetic energy increases when the bed is movable. The evolution of bed morphology is closely related to the flow structure and the growth of the von Karman vortex street. Both the rising length and the adjusted length decrease with increasing patch density, while the incoming sediment causes an increase in the adjusted length. Behind the patch wake, the first minimum elevation, maximum elevation, and second minimum elevation decrease as the patch density increases. These values, in turn, increase with the sediment supply upstream of the flume.

Hypsometric Analysis of WRC-1 Watershed, Chargarh River Basin, Central India: A Remote Sensing and GIS Approach

Hypsometric analysis is a valuable tool for determining the tectonic evolution of a river basin and the erosion susceptibility. It is also important for integrated watershed management, which include selecting suitable locations for groundwater recharge structures and for conservation of soil and water. This type of study can analyze the relationship between horizontal cross sectional area and the altitude of the watershed. It evaluates the hypsometric curve and hypsometric integral, as generated for the WRC-1 watershed, Chargarh river basin through remote sensing and GIS technique. In the present case, hypsometric analysis was carried out using Survey of India topographic maps, Arc map-10.2 software and SRTM-DEM. The hypsometric integral is calculated using mean elevation minus minimum elevation, divided by relief. The hypsometric curve, with a value of 0.69 for the hypsometric integral clearly indicates an inequilibrium stage (youthful stage) of geomorphic development, which is highly susceptible to erosion. These interpretations can further utilize appropriate measures of soil and water conservation for long-term development within the WRC-1 watershed.

Spatial distribution of rock uplift in the Bongarà district (Peruvian Andes) and implications for the genesis of supergene ore deposits

Topography and river landscape morphometry of two hydrographic basins, the Utcubamba River and the Chiriaco River basins (Bongará district, Amazonas region) allowed to determine the relationship between the irregular distribution of vertical motions (e.g., rock uplift) and the genesis of supergene Zn deposits. The latter derives from variable weathering of pre-existing carbonate-hosted Zn sulfides orebodies, in three distinct localities: Florida Canyon, Mina Grande and Cristal. The research was carried out through the evaluation of the parameters such as elevation, local relief, swath profile, river longitudinal profiles and transformed river profiles (χ-long profiles), and slope/area analysis to derive the normalized channel steepness index (ksn). The NE-ward sharp increase in mean and minimum elevation coupled with a jump in the mean ksn values, suggests that the Chiriaco River basin has experienced more recent rock uplift than the Utcubamba River basin. In fact, the Utcubamba River experienced a long-lasting uplift, resulting in a rugged local relief and lowering the mean and minimum elevations, and exhumation and weathering of the Triassic-hosted sulfide mineral deposits at Florida Canyon. In the Chiriaco River basin, the younger uplift has promoted the weathering of the more surficial Jurassic-hosted Mina Grande and Cristal mineral deposits. The morphometric approach proved to be effective in recognizing fertile areas with near-surface orebodies also in regions characterized by distinct types of ore deposits.

Quantifying the influence of climate, host and change in land-use patterns on occurrence of Crimean Congo Hemorrhagic Fever (CCHF) and development of spatial risk map for India

Crimean Congo Hemorrhagic Fever (CCHF), is an emerging zoonosis globally and in India. The present study focused on identifying the risk factors for occurrence of CCHF in the Indian state of Gujarat and development of risk map for India. The past CCHF outbreaks in India were collated for the analyses. Influence of land use change and climatic factors in determining the occurrence of CCHF in Gujarat was assessed using Bayesian spatial models. Change in maximum temperature in affected districts was analysed to identify the significant change points over 110 years. Risk map was developed for Gujarat using Bayesian Additive Regression Trees (BART) model with remotely sensed environmental variables and host (livestock and human) factors. We found the change in land use patterns and maximum temperature in affected districts to be contributing to the occurrence of CCHF in Gujarat. Spatial risk map developed using CCHF occurrence data for Gujarat identified density of buffalo, minimum land surface temperature and elevation as risk determinants. Further, spatial risk map for the occurrence of CCHF in India was developed using selected variables. Overall, we found that combination of factors such as change in land-use patterns, maximum temperature, buffalo density, day time minimum land surface temperature and elevation led to the emergence and further spread of the disease in India. Mitigation measures for CCHF in India could be designed considering disease epidemiology and initiation of surveillance strategies based on the risk map developed in this study.

Design of an Open Channel for Flood and Gully Erosion Control: A Case Study of Amakohia-Uratta in Imo State, Nigeria

Flooding and gully erosion constitute a major problem associated with urbanization in the underlying watershed of an area. In this study, a trapezoidal channel hydraulic system was designed for flood and erosion control in Amakohia-Uratta, Owerri North, Imo state, Nigeria. A topographical survey of the study area was done. The result shows that the maximum elevation is 81.03 m, the minimum elevation is 78.21 m, the bed slope of the area is 0.02%, the area of the watershed is 1.061ha, and the maximum length of flow is 140m. Also, the results from the hydrological analysis using the rational method indicated that the rainfall intensity of 10 years duration was 105.3 mm/h with a peak discharge Qp of 0.17 m3/s, causing the flood and erosion, while the channel design capacity (discharge) Qd is 0.17 m3/s, calculated using trial and error methods. Finally, design parameters for the trapezoidal open channel were calculated. The result indicated that the channel width is 0.3 m, the design depth is 0.5 m, the freeboard is 0.1m, the total channel depth is 0.6m, the top width of the channel is 2.1 m and the side slope is 1.5:1. In all the design is appropriate to capture, carry and discharge the peak runoff to Nworie River a natural outlet.

Quantifying geomorphic change in Andean river valleys using UAV-PPK-SfM techniques: An example from the western Peruvian Andes

The western Peruvian region is prone to erosion and geomorphic change. Extreme precipitation events lead to rapid change in river channel and floodplain morphology due to bank erosion and debris flows delivering detrital material to the fluvial system. Monitoring geomorphic events and their associated topographic changes at high spatial and temporal resolutions remains a challenge. Here, we used an Uncrewed Aerial Vehicle - Post-Processing Kinematic - Structure from Motion (UAV-PPK-SfM) approach that includes co-registration of point clouds by using relative Ground Control Points (GCPs). This workflow adjusts each elevation model to a reference model using invariant features that did not change their position or form over time. We applied this technique to monitor landscape change (2019–2021) in an area of 0.3 km2 located in the Cañete River basin. Our results showed that a minimum observable elevation change of 0.56 m (95 % confidence interval) can be achieved using this workflow, beyond which an actual elevation change can be separated from systematic error. Using object-based classification techniques on the aerial images, we separated geomorphic dynamics from land cover changes. This allowed us to isolate the effect of geomorphic processes, and quantify rates related to gully erosion, river scouring, bank erosion, and sediment deposition. Within the study area, a hotspot of geomorphic change corresponded to an ephemeral tributary channel. The gully channel incising an alluvial fan is highly dynamic, showing bank erosion of 0.75 to 3.2 m and net export of 37 m3 of sediment in the 25-month study period. Given that the monitoring period did not include high intensity rainfall events, the study illustrates how geomorphic activity in ungauged Andean river basins, such as the Cañete valley, may be considerably underestimated in literature.

Clinical Results of Accelerated Iontophoresis-Assisted Epithelium-on Corneal Cross-linking for Progressive Keratoconus in Children.

To evaluate the clinical characteristics of pediatric patients with progression of keratoconus after accelerated iontophoresis-assisted epithelium-on corneal cross-linking (I-ON CXL) and to assess the efficacy and safety of re-treatment using accelerated epithelium-off CXL (epi-OFF CXL). Sixteen eyes of 16 patients (mean age: 14.6 ± 2.5 years) with keratoconus underwent I-ON CXL. The main outcome measures were uncorrected distance visual acuity, corrected distance visual acuity, maximum keratometry index (Kmax), minimum corneal thickness, elevation front and elevation back measured at the thinnest point, total higher order aberrations root main square (HOA RMS), coma RMS, and spherical aberration. An increment of Kmax greater than 1.00 diopter (D) and a decrease of greater than 20 µm in pachymetry were considered to determine the progression of keratoconus. Patients with progression of keratoconus after I-ON CXL were re-treated using an epi-OFF CXL protocol. Two years after I-ON CXL, 12 patients showed progression of keratoconus, whereas 4 patients were stable. There was significant worsening of Kmax (P = .04) and steepest keratometric reading (P = .01). Furthermore, a significant correlation was documented between progression of keratoconus and age (P = .02). These patients were re-treated using an epi-OFF protocol and after 2 years all patients were stable, and a statistically significant reduction of the mean Kmax (P = .007), HOA RMS (P = .05), and coma RMS (P = 05) was observed. I-ON CXL was ineffective in the treatment of pediatric keratoconus in younger children, whereas it had an efficacy of 2 years in older children. Re-treatment using epi-OFF CXL proved effective to halt progression of keratoconus after I-ON CXL failure. [J Pediatr Ophthalmol Strabismus. 2024;61(1):44-50.].

Field Measurements of Bridge Pier Scour in a Curved Channel

Pier scour is the most common cause of bridge failures, so the problem for the erosion of soil surrounding a bridge foundation has attracted extensive attention. The Jiaxing-Shaoxing Bridge (JSB) is located in Jianshan bend of the Qiantang River Estuary (QRE). The special flow structure and bed morphology of the bend makes the scouring characteristics of the piers particularly complex. Based on the results of Multibeam Echosounders for topographic surveying in recent six years, the scouring characteristics of pier foundation of a main navigation channel of the JSB are analysed in this paper. The results show that with the implementation of the reclamation project in the QRE area, the river channel has been gradually narrowed, coupled with the sharp reduction of the sediment entering the sea of the Yangtze River, the river regime swing in the QRE has changed significantly compared with that in the original design stage of the JSB. Under adverse river regime hydrological conditions, the riverbed erosional depth near the bridge is remarkable, and the local scouring depth of the pier is superimposed, which significantly will reduce the minimum elevation of the bed around the pier.