Capability of space borne multispectral image for detecting discoloration in optically complex coastal waters.

Coastal pollutants, from harmful algal blooms, sewage and industrial discharges, pose severe risks to marine ecosystems and public health. Recently, Promenade Beach in Puducherry, Southeast-India, experienced reddish-brown water discoloration, suspected to result from either algal blooms or suspended matter. This study monitored the spatial extent and characteristics of the discoloration using Sentinel-2 satellite images from September to November 2023, with field observations and laboratory analyses. Analyses included measurements of chlorophyll-a (Chl-a), Total Suspended Matter (TSM), and the Normalized Difference Chlorophyll Index (NDCI) to differentiate between algal blooms and other pollutants. The satellite data indicated extents of discoloration, with high TSM concentrations (>45 g/m3) and negative NDCI values suggesting absence of algal blooms. No mortality of aquatic organisms was observed during this discoloration, indicating no deleterious impact on aquatic life. This approach highlights the importance of combining satellite technology with field data for effective coastal pollution monitoring, essential for protecting marine ecosystems.

Vehicular Traffic Flow Analysis and Minimize the Vehicle Queue Waiting Time Using Signal Distribution Control Algorithm.

The real-time vehicular traffic system is an integral part of the urban vehicular traffic system, which provides effective traffic signal control for a large multifaceted traffic network and is a highly challenging distributed control problem. Coordinating vehicular traffic enables the network model to deliver an efficient service flow. Consider that there are four lanes of vehicular traffic in this situation, allowing parallel vehicle movements to occur without causing an accident. In this instance, the vehicular system's control parameters are time and vehicle volume. In this work, vehicular traffic flow is examined, and an algorithm to estimate vehicle waiting time in each direction is estimated. The effectiveness of the proposed vehicle traffic signal distribution control system by comparing the experimental results with a real-time vehicular traffic system is verified. This is also illustrated numerically.

Mapping of tide-dominated Hooghly estuary water quality parameters using Sentinel-3 OLCI time-series data.

The study explores the spatio-temporal variation of water quality parameters in the Hooghly estuary, which is considered an ecologically-stressed shallow estuary and a major distributary for the Ganges River. The estimated parameters are chlorophyll-a, total suspended matter (TSM), and chromophoric dissolved organic matter (CDOM). The Sentinel-3 OLCI remote sensing imageries were analyzed for the duration of October 2018 to February 2019. We observed that the water quality of the Hooghly estuaries is comparatively low-oxygenated, mesotrophic, and phosphate-limited. Ongoing channel dredging for maintaining shipping channel depth keeps the TSM in the estuary at an elevated level, with the highest amount of TSM observed during March of 2019 (41.59g m-3) at station A, upstream point. Since the pre-monsoon season, TSM data shows a decreasing trend towards the mouth of the estuary. Chl-a concentration is higher during pre-monsoon than monsoon and post-monsoon periods, with the highest value observed in April at 1.09 mg m-3 in station D during the pre-monsoon period. The CDOM concentration was high in the middle section (January-February) and gradually decreased towards the estuary's head and mouth. The highest CDOM was found in February at locations C and D during the pre-monsoon period. Every station shows a significant correlation among CDOM, TSM, and Chl-a measured parameters. Based on our satellite data analysis, it is recommended that SNAP C2RCC be regionally used for TSM, Chl-a, and CDOM for water quality product retrieval and in various algorithms for the Hooghly estuary monitoring.

Response of total suspended matter to natural and anthropogenic factors since 1990 in China's large lakes.

Total suspended matter (TSM) as a critical water quality parameter is closely linked with nutrients, micropollutants, and heavy metals threatening the ecological health of aquatic ecosystems. However, the long-term spatiotemporal dynamics of lake TSM in China and their response to natural and anthropogenic factors are rarely explored. In this study, based on Landsat top-of-atmosphere (TOA) reflectance embedded in GEE and in-situ TSM data collecting in the periods 2014-2020, we developed a unified empirical model (R2 = 0.87, RMSE = 10.16 mg/L, and MAPE = 38.37 %) to retrieve the autumn TSM of lakes at national scale. This model exhibited stable and reliable performances through transferability validation and comparative analysis with published TSM models, and was implemented to generate autumn TSM maps for large lakes (≥50 km2) across China during 1990-2020.We found that 78.03 % of large lakes with TSM < 20 mg/L were dominant in 2020 across China, and these lakes were mainly located in the plateau and mountain regions. In the first gradient terrain (FGT) and second gradient terrain (SGT), the number of lakes showing significant (p < 0.05) decreasing TSM trends increased from 1990-2004 to 2004-2020, while those with opposite directions in TSM decreased. Lakes in the third gradient terrain (TGT) exhibited the inverse quantitative change in these two TSM trends compared with the FGT and SGT. A relative contribution analysis at the watershed level indicated that the first two leading factors that control TSM significant change in the FGT were lake area and wind speed, in the SGT were lake area and NDVI, and in the TGT were population and NDVI, respectively. The impacts of anthropogenic factors on lakes are continuing, particularly in eastern China, and more efforts are needed to improve and protect the water environment in the future. Our findings might help water resource managers better grasp the current state of water quality.

The Economy of Motion for Laparoscopic Ball Clamping Surgery: A Feedback Educational Tool.

The Ball Clamping module of the Laparoscopic Surgery Training Box involves the transfer of beads across the training board using laparoscopic tools. Fundamentals of Laparoscopic Surgery (FLS) requires practitioners to move their hands at as short a distance as possible to perform the functions in the shortest amount of time. This study introduces a feedback tool that presents to the student, after attempting their exam, the right direction (step by step) of obtaining the optimal pathway for minimizing distance traveled in the Ball Clamping Module of the Laparoscopic Surgery Training Box. The shortest distance tour for the ball clamping task is determined using the Traveling Salesman Model (TSM). A sensitivity analysis is conducted to assess the model's applicability to different types and settings of trainer boxes.•Find the best sequence of points resulting in the shortest distance tour for the ball clamping task.•The effects of adding or removing columns from the box cannot be intuitively predicted.

Variation of satellite-derived total suspended matter in large lakes with four types of water storage across the Tibetan Plateau, China.

Total suspended matter (TSM), as an indicator of the concentration of fine materials in the water column including particulate nutrients, pollutants, and heavy metals, is widely used to monitor aquatic ecosystems. However, the long-term spatiotemporal variations of TSM in lakes across the Tibetan Plateau (TP) and their response to environmental factors are rarely explored. Accordingly, taking advantage of the Landsat top-of-atmosphere reflectance and in-situ data, an empirical model (R2 = 0.83, RMSE = 1.08 mg/L, and MAPE = 19.49 %) was developed to estimate the average autumnal TSM in large TP lakes (≥50 km2) during the 1990-2020 period. For analyzing the spatiotemporal variability in TP lakes TSM, the examined lakes were classified into four types (Type A-D) based on their water storage changing in different periods. The results showed that the lakes in the southern and some northeastern parts of the TP exhibited lower TSM values than those situated in other regions. The assessment of TSM in each of these four lake types showed that more than half of them had a TSM value of <20 mg/L. Apart from Type D, the lakes with the TSM showing significantly decreasing trends were dominantly Types A-C. A relative contribution analysis involving five driving factors indicated that they contributed by >50 % to lake TSM interannual variation in 73 out of 114 watersheds, and the lakes area change demonstrated the greatest contribution (82.2 %), followed by wind speed (11.0 %). Further comparison between the entire lake and the non-expansive regions suggested that the expansive region played an indispensable role in determining the TSM value of the whole lake. This study can help to better understand the water quality condition and provide valuable information for policy-makers to maintain sustainable development in the TP region.

Effects of Ferroptosis on the Metabolome in Cardiac Cells: The Role of Glutaminolysis.

Ferroptosis is a novel iron-dependent regulated cell death mechanism that affects cell metabolism; however, a detailed metabolomic analysis of ferroptotic cells is not yet available. Here, we elucidated the metabolome of H9c2 cardioblasts by gas chromatography-mass spectrometry during ferroptosis induced by RSL3, a GPX4 inhibitor, in the presence of ferrostatin-1 (a ferroptosis inhibitor), XJB-5-131 (a mitochondrial-targeted ROS scavenger), or TSM-1005-44 (a newly developed cellular ROS scavenger). Results demonstrated that RSL3 decreased the levels of amino acids involved in glutathione synthesis more than two-fold. In contrast, saturated fatty acids levels were markedly increased in RSL3-challenged cells, with no effects on unsaturated fatty acids. RSL3 significantly altered the levels of mitochondrial tricarboxylic acid cycle intermediates; isocitrate and 2-oxoglutarate were found to increase, whereas succinate was significantly decreased in RSL3-challenged cells. Ferrostatin-1, XJB-5-131, and TSM-1005-44 prevented RSL3-induced cell death and conserved the metabolomic profile of the cells. Since 2-oxoglutarate is involved in the regulation of ferroptosis, particularly through glutamine metabolism, we further assessed the role of glutaminolysis in ferroptosis in H9c2 cardioblasts. Genetic silencing of GLS1, which encodes the K-type mitochondrial glutaminase (glutaminase C), protected against ferroptosis in the early stage. In conclusion, our study demonstrates that RSL3-induced ferroptosis impairs the metabolome of H9c2 cardioblasts.

SPECTRA: a tool for enhanced brain wave signal recognition.

BACKGROUND: Brain wave signal recognition has gained increased attention in neuro-rehabilitation applications. This has driven the development of brain-computer interface (BCI) systems. Brain wave signals are acquired using electroencephalography (EEG) sensors, processed and decoded to identify the category to which the signal belongs. Once the signal category is determined, it can be used to control external devices. However, the success of such a system essentially relies on significant feature extraction and classification algorithms. One of the commonly used feature extraction technique for BCI systems is common spatial pattern (CSP). RESULTS: The performance of the proposed spatial-frequency-temporal feature extraction (SPECTRA) predictor is analysed using three public benchmark datasets. Our proposed predictor outperformed other competing methods achieving lowest average error rates of 8.55%, 17.90% and 20.26%, and highest average kappa coefficient values of 0.829, 0.643 and 0.595 for BCI Competition III dataset IVa, BCI Competition IV dataset I and BCI Competition IV dataset IIb, respectively. CONCLUSIONS: Our proposed SPECTRA predictor effectively finds features that are more separable and shows improvement in brain wave signal recognition that can be instrumental in developing improved real-time BCI systems that are computationally efficient.

Improving Real-Time Hand Gesture Recognition with Semantic Segmentation.

Hand gesture recognition (HGR) takes a central role in human-computer interaction, covering a wide range of applications in the automotive sector, consumer electronics, home automation, and others. In recent years, accurate and efficient deep learning models have been proposed for real-time applications. However, the most accurate approaches tend to employ multiple modalities derived from RGB input frames, such as optical flow. This practice limits real-time performance due to intense extra computational cost. In this paper, we avoid the optical flow computation by proposing a real-time hand gesture recognition method based on RGB frames combined with hand segmentation masks. We employ a light-weight semantic segmentation method (FASSD-Net) to boost the accuracy of two efficient HGR methods: Temporal Segment Networks (TSN) and Temporal Shift Modules (TSM). We demonstrate the efficiency of the proposal on our IPN Hand dataset, which includes thirteen different gestures focused on interaction with touchless screens. The experimental results show that our approach significantly overcomes the accuracy of the original TSN and TSM algorithms by keeping real-time performance.

Inversion and distribution of total suspended matter in water based on remote sensing images-A case study on Yuqiao Reservoir, China.

In this paper, Yuqiao Reservoir is taken as the research object. The total suspended matter (TSM) produced by the economic development in the upper reaches of the reservoir and its surrounding areas has brought great ecological harm to the safe operation of the reservoir. Satellite remote sensing technology provides a good way to obtain the temporal and spatial variation of TSM in the study area. Two field surveys were carried out in the Yuqiao Reservoir, a total of 44 sampling points collected in the two tests. The spectral data and concentration of TSM were obtained. We developed and validated a robust empirical model to estimate the concentration of TSM in the water of the Yuqiao Reservoir for the first time. The TSM distribution map of the Yuqiao Reservoir in 2013-2018 is retrieved based on Landsat 8 OLI images. This paper analyzes the spatial distribution characteristics of TSM concentration in the Yuqiao Reservoir for several years, as well as the interannual, seasonal, and monthly variation laws and development trends. The results show that the spatial distribution of TSM in Yuqiao Reservoir shows a decreasing trend from the periphery to the center; the interannual changes are mainly as follows: The annual change trend of TSM in Yuqiao Reservoir is not obvious; the seasonal changes are significant: the highest in summer (higher than 40 mg/L), the second in autumn, and the lowest in spring and winter (lower than 15 mg/L); and the monthly changes show regular fluctuations: In a year cycle, the concentration of TSM generally shows an inverted V-shaped trend; that is, TSM increases gradually from January to August and decreases gradually from August to December. The research results of this paper can be applied to other similar types of land water bodies, which will promote the wide application of Landsat 8 OLI images in the monitoring of TSM in lakes, rivers, and reservoirs in different regions across China, and provide data support for the scientific management of the safe operation of research areas. PRACTITIONER POINTS: The monitoring model of TSM in Yuqiao Reservoir was built for the first time. Temporal and spatial analysis of TSM concentration in Yuqiao Reservoir for the first time. The concentration of TSM is in Yuqiao Reservoir greatly affected by wind speed and precipitation.

Empirical relationships for remote sensing reflectance and Noctiluca scintillans cell density in the northeastern Arabian Sea.

A dinoflagellate under the ambit of Harmful Algal Blooms (HAB), the bioluminescent Noctiluca scintillans (NS), has been infesting the northern Arabian Sea increasingly over the last few decades during late winter. Their occurrence is found to be due to seasonal oscillations in the coastal currents. The physical and biogeochemical parameters associated with the seasonal blooms are reasonably well known. But accurate quantitative estimation capability using remote sensing sensors over the extensive oceanic regime is still lacking. This is especially due to a lack of information on bio-optical properties associated with cell density measurements. We attempted to show that remote sensing reflectance and chl-a show significant relationship e.g., Rrs(531)/Rrs(510) = 0.8261 + 6.06 × 10-6NS + 0.02323chl-a (N = 19, R2adj = 0.99, p = 2.5 × 10-17, RMSE = 0.1083) which is applicable over diverse areas of the northeastern Arabian Sea e.g., coastal, shelf and offshore regions. The model is supported by a second dataset with an RMSE of 0.022893 (N = 8) for the Rrs(531)/Rrs(510) ratio. The NS cell densities were derived from the Rrs(510)/Rrs(531) band ratio within reasonable error and accuracy limits. Including sensor capability at 510 nm is suggested in future satellite launches.

Quantifying total suspended matter (TSM) in waters using Landsat images during 1984-2018 across the Songnen Plain, Northeast China.

Understanding the spatiotemporal dynamics of total suspended matter (TSM) in waters is necessary to promote efficient water resource management. In our study, we have estimated the spatiotemporal pattern of TSM with the combination of time-series Landsat images and field survey. Among various remote sensing-derived parameters, the red/blue band turns to be robust and the most sensitive to the TSM from field measurements. In Songnen Plain, the mean annual TSM in 60.5% of the water bodies decreased from 1984 to 2018. The decreasing of TSM is likely due to the increasing of vegetation in the area. The TSM concentration in waters declined from April to July, and then increased from September onwards. We also found the TSM in water bodies in Songnen Plain has very high spatial variation. Our results indicated that the meteorological factors such as wind and precipitation may affect the variation of TSM. Our results demonstrate that long-term Landsat data are useful to examine TSM in inland waters. Our findings can support for water resource management under human activities and climate change.

Relationship between the degree of abdominal wall movement and the image quality of contrast-enhanced MRI: semi-quantitative study especially focused on the occurrence of transient severe motion artifact.

PURPOSE: To reveal the relationship between abdominal movement and artifact, and to reveal if the transient artifact in arterial phase is caused by transient abdominal movement (TAM) in contrast-enhanced (CE) MRI. MATERIALS AND METHODS: 325 CE-MRI series (206 with EOB and 119 with EGCM) were included. The abdominal movement was classified into three groups by respiratory bellows waveform (= bellows grade, BG 1-3), and MR image quality (= artifact score, AS) was graded 1-5 for the precontrast, arterial and portal venous phase, respectively. The relationship between the BG and AS was evaluated. The occurrence of transient artifact in arterial phase was compared to the degree of TAM. RESULTS: In the acquisitions with BG3, all images showed AS of > 2, while no images had AS of > 4 in the acquisitions with BG1. Numbers of transient artifact in the arterial phase with no-abdominal movement (NAM), mild-TAM, severe-TAM were 0 of 120, 4 of 27, 7 of 8 in EOB and 0 of 91, 1 of 4, 0 of 0 in EGCM, respectively. CONCLUSION: Image quality is highly correlated with abdominal movement. Moreover, artifact in arterial phase was not observed in NAM, which indicated abdominal movement is the direct cause of artifact.

Larvae of Caribbean Echinoids Have Small Warming Tolerances for Chronic Stress in Panama.

In species with complex life cycles, early developmental stages are often less thermally tolerant than adults, suggesting that they are key to predicting organismal response to environmental warming. Here we document the optimal and lethal temperatures of larval sea urchins, and we use those to calculate the warming tolerance and the thermal safety margin of early larval stages of seven tropical species. Larvae of Echinometra viridis, Echinometra lucunter, Lytechinus williamsi, Eucidaris tribuloides, Tripneustes ventricosus, Clypeaster rosaceus, and Clypeaster subdepressus were reared at 26, 28, 30, 32, and 34 °C for 6 days. The temperatures at which statistically significant reductions in larval performance are evident are generally the same temperatures at which statistically significant reductions in larval survival were detected, showing that the optimal temperature is very close to the lethal temperature. The two Echinometra species had significantly higher thermal tolerance than the other species, with some surviving culture temperatures of 34 °C and showing minimal impacts on growth and survival at 32 °C. In the other species, larval growth and survival were depressed at and above 30 or 32 °C. Overall, these larvae have lower warming tolerances (1 to 5 °C) and smaller thermal safety margins (-3 to 3 °C) than adults. Survival differences among treatments were evident by the first sampling on day 2, and survival at the highest temperatures increased when embryos were exposed to warming after spending the first 24 hours at ambient temperature. This suggests that the first days of development are more sensitive to thermal stress than are later larval stages.

Seasonal variability in plankton food web composition in Tuticorin coastal waters, south east coast of India.

To understand the impact of seasonal variability on plankton food web composition in tropical coastal waters, samples were collected from three locations along Tuticorin coastal waters during postmonsoon, summer, and northeast (NE) monsoon seasons. During the NE monsoon, the total suspended matter (TSM) and nutrient concentrations were relatively higher, whereas salinity and plankton (phytoplankton and zooplankton) abundances were lower. Cluster analysis also revealed that the NE monsoon formed into a separate cluster because of the lower phytoplankton abundance caused by higher loads of TSM; this arrests light penetration, thereby resulting in a decrease in plankton abundance. The increase in zooplankton biomass coincided with the decrease in diatoms (p < 0.05), and the increase in cyanobacteria may reflect that grazers food choice has a significant impact on the base of the food web composition. The present study states that the phytoplankton biomass was greatly influenced by seasonality and associated changes rather than the huge supply of nutrient loads.

Three types of dural suturing for closure of CSF leak after endoscopic transsphenoidal surgery.

OBJECTIVE: Transsphenoidal surgery (TSS) is commonly used for anterior skull base surgery, especially in the sella turcica (sellar) region. However, because of its anatomical position, CSF leakage is a major complication of this approach. The authors introduced a new grading reconstruction strategy for anterior skull base surgery with continuous dural suturing in 2013. In this paper the authors report on their methods and results. METHODS: All patients with sellar or anterior skull base lesions that were removed with TSS or extended TSS by a single neurosurgeon between April 2013 and March 2017 at Nagoya University Hospital and several cooperating hospitals were retrospectively identified. Three methods of suturing dura were considered, depending on the dural defect. RESULTS: There were 176 TSS cases (141 conventional TSS cases and 35 extended endoscopic TSS cases) and 76 cases of Esposito's grade 2 or 3 intradural high-flow CSF leakage. In the high-flow CSF leak group, there were 3 cases of CSF leakage after the operation. The rates of CSF leakage after surgery corresponding to grades 2 and 3 were 2.9% (1/34) and 4.7% (2/42), respectively. CONCLUSIONS: Dural suturing is a basic and key method for reconstruction of the skull base, and continuous suturing is the most effective approach. Using this approach, the frequency of cases requiring a nasoseptal flap and lumbar drainage can be reduced.

APOBEC and ADAR deaminases may cause many single nucleotide polymorphisms curated in the OMIM database.

Cytosine and adenosine deamination events (DNA, RNA substrates) account for most codon-context Targeted Somatic Mutation (TSM) patterns observed in immunoglobulin (Ig) somatic hypermutation (SHM), and in cancer exomes following Ig-SHM-like responses. TSM refers to the process of somatic mutagenesis involving deamination events that results on a dominant type of mutation (e.g., C-to-T), and co-incident at a particular motif (e.g., WRC), and preferentially targeting the first, second or third nucleotide position within the mutated codon (e.g. MC1, MC2 or MC3, read 5-prime to 3-prime). It is now widely accepted that if left uncorrected, the accumulation of uncorrected TSMs involving the deaminases, may lead to a diagnosis of cancer or other degenerative disease. Our hypothesis is that many missense, nonsense and synonymous single nucleotide polymorphisms (SNPs) associated with clinically significant diseases may have arisen in the population by similar highly targeted deamination events. The OMIM database was searched for disease-associated SNPs on the X chromosome, and for all chromosomes. The nucleotide substitution patterns for disease-associated SNPs were analyzed by the TSM method to identify the likely deaminase source for C-to-U (C-to-T/G-to-A) and A-to-I (A-to-G/T-to-C) derived gene mutations preferentially targeting known sequence motifs associated with the deaminases: AID, APOBEC3G, APOBEC3B and ADAR 1/2. Of the 789 OMIM SNPs analysed. In both data sets, the mutation targeting preferences within the mutated codon reveal a statistically significant bias (p < 0.001). The results imply that a deamination of C-site and A-site targets are written into the human germline for the chromosome wide exomic SNPs analysed. This is consistent with previously observed mutation patterns arising in cancer genomes and hypermutated Ig genes during SHM. The results imply that similar types of deaminase-mediated molecular processes that occur in somatic hypermutation and cancer, may be contributing causative drivers of human exomic SNPs.

Tuberculum sellae meningiomas: grading scale to assess surgical outcomes using the transcranial versus transsphenoidal approach.

OBJECTIVE Tuberculum sellae meningiomas (TSMs) are surgically challenging tumors that can severely impair vision. Debate exists regarding whether the transcranial (TC) or endoscopic transsphenoidal (TS) approach is best for resecting these tumors, and there are few large series comparing these approaches. METHODS A retrospective chart review was performed at 2 academic centers comparing TC and TS approaches with respect to vision, extent of resection, recurrence, and complications. The authors report surgical outcomes and propose a simple preoperative tumor grading scale that scores tumor size (1-2), optic canal invasion (0-2), and arterial encasement (0-2). The authors performed univariate, multivariate, and recursive partitioning analysis (RPA) to evaluate outcomes. RESULTS The TSMs were resected in 139 patients. The median follow-up was 29 months. Ninety-five (68%) cases were resected via a TC and 44 (32%) via a TS approach. Tumors treated via a TC approach had a higher tumor (p = 0.0007), artery (p < 0.0001), and total score (p = 0.0012) on the grading scale. Preoperative visual deficits were present in 87% of patients. Vision improved in 47%, stayed the same in 35%, declined in 10%, and was not recorded in 8%. The extent of resection was 65% gross-total resection, 23% near-total resection (95%-99% resection), and 12% subtotal resection (< 95%). A lower tumor score was significantly associated with better or stable vision postoperatively (p = 0.0052). The RPA confirmed low tumor score as the key predictor of postoperative visual improvement or stability. Multivariate analysis and RPA demonstrate that lower canal score (p < 0.0001) and TC approach (p = 0.0019) are associated with gross-total resection. Complications occurred in 20 (14%) patients, including CSF leak (5%) and infection (4%). There was no difference in overall complication rates between TC and TS approaches; however, the TS approach had more CSF leaks (OR 5.96, 95% CI 1.10-32.04). The observed recurrence rate was 10%, and there was no difference between the TC and TS approaches. CONCLUSIONS Tuberculum sellae meningiomas can be resected using either a TC or TS approach, with low morbidity and good visual outcomes in appropriately selected patients. The simple proposed grading scale provides a standard preoperative method to evaluate TSMs and can serve as a starting point for selection of the surgical approach. Higher scores were associated with worsened visual outcomes and subtotal resection, regardless of approach. The authors plan a multicenter review of this grading scale to further evaluate its utility.

Monitoring water quality in a hypereutrophic reservoir using Landsat ETM+ and OLI sensors: how transferable are the water quality algorithms?

The launch of the Landsat 8 in February 2013 extended the life of the Landsat program to over 40 years, increasing the value of using Landsat to monitor long-term changes in the water quality of small lakes and reservoirs, particularly in poorly monitored freshwater systems. Landsat-based water quality hindcasting often incorporate several Landsat sensors in an effort to increase the temporal range of observations; yet the transferability of water quality algorithms across sensors remains poorly examined. In this study, several empirical algorithms were developed to quantify chlorophyll-a, total suspended matter (TSM), and Secchi disk depth (SDD) from surface reflectance measured by Landsat 7 ETM+ and Landsat 8 OLI sensors. Sensor-specific multiple linear regression models were developed by correlating in situ water quality measurements collected from a semi-arid eutrophic reservoir with band ratios from Landsat ETM+ and OLI sensors, along with ancillary data (water temperature and seasonality) representing ecological patterns in algae growth. Overall, ETM+-based models outperformed (adjusted R2 chlorophyll-a = 0.70, TSM = 0.81, SDD = 0.81) their OLI counterparts (adjusted R2 chlorophyll-a = 0.50, TSM = 0.58, SDD = 0.63). Inter-sensor differences were most apparent for algorithms utilizing the Blue spectral band. The inclusion of water temperature and seasonality improved the power of TSM and SDD models.

Distributed Finite Time Consensus of Secondorder Multi-agent Systems via Pinning Control (August 2018).

The robust distributed finite time consensus of second-order multi-agent systems via pinning control has been investigated in this paper. A new nonsingular finite time TSM control method is proposed for second-order single system with disturbances. Based on the pinning error function vector, robust distributed finite time consensus of second-order multi-agent systems via pinning control method is given. Simulations results are performed to validate the effectiveness of the theoretical results.