Attitude control of a 3-DoF quadrotor platform using a linear quadratic integral differential game approach.

In this study, a linear quadratic integral differential game approach is applied to regulate and track the Euler angles for a quadrotor experimental platform using two players. One produces commands for each channel of the quadrotor and another generates the worst disturbance based on the mini-maximization of a quadratic criterion with integral action. For this purpose, first, the attitude dynamics of the platform are modeled and its parameters are identified based on the Nonlinear Least Squares Trust-Region Reflective method. The performance of the proposed controller is evaluated for regulation and tracking problems. The ability of the controller is also examined in the disturbance rejection. Moreover, the influence of uncertainty modeling is studied on the obtained results. Then, the performance of the proposed controller is compared with the classic Proportional Integral Derivative, Linear Quadratic Regulator, and Linear Quadratic Integral Regulator. The results demonstrate the effectiveness of the Game Theory on the Linear Quadratic Regulator approach when the input disturbance occurs.

Hydro-meteorological droughts across the Baltic Region: The role of the accumulation periods.

Based on the physical and geographical conditions, the Baltic Region is categorised as a humid climate zone. This means that, there is usually more precipitation than evaporation throughout the year, suggesting that droughts should not occur frequently in this region. Despite the humid climate in the region, the study focused on assessing the spatio-temporal patterns of droughts. The drought events were analysed across the Baltic Region, including Sweden, Finland, Lithuania, Latvia, and Estonia. This analysis included two drought indices, the Standardized Precipitation Index (SPI) and the Streamflow Drought Index (SDI), for different accumulation periods. Daily data series of precipitation and river discharge were used. The spatial and temporal analyses of selected drought indices were carried out for the Baltic Region. In addition, the decadal distribution of drought classes was analysed to disclose the temporal changes and spatial extent of drought patterns. The Pearson correlation between SPI and SDI was applied to investigate the relationship between meteorological and hydrological droughts. The analysis showed that stations with more short-duration SPI or SDI cases had fewer long-duration cases and vice versa. The number of SDI cases (SDI ≤ -1) increased in the Western Baltic States and some WGSs in Sweden and Finland from 1991 to 2020 compared to 1961-1990. The SPI showed no such tendencies except in Central Estonia and Southern Finland. The 6-month accumulation period played a crucial role in both the meteorological and hydrological drought analyses, as it revealed prolonged and widespread drought events. Furthermore, the 9- and 12-month accumulation periods showed similar trends in terms of drought duration and spatial extent. The highest number of correlation links between different months was found between SPI12-SDI9 and SPI12-SDI12. The results obtained have deepened our understanding of drought patterns and their potential impacts in the Baltic Region.

Can river flow prevent land subsidence in urban areas?

Land subsidence, a silent death, occurs due to various factors like significant reduction in groundwater (GW) levels. It is a widespread phenomenon with irreparable consequences on buildings, infrastructures, and, in severe cases, groundwater aquifers. This study aims to assess the impact of river flow on the acceleration and control of land subsidence in an arid and semi-arid region. To achieve this goal, we analyze the interconnection between GW and SW and investigate the role of the Zayandeh-Rud River's drying up on land subsidence in the Isfahan-Borkhar aquifer in Iran's central plateau. To facilitate this assessment, we utilize the Interferometric Synthetic Aperture Radar (InSAR) technique to estimate the vertical deformation velocity of the aquifer (average land subsidence rate). The results show that the Isfahan-Borkhar aquifer has experienced a significant annual decline of more than 25 m, with an alarming rate exceeding 0.8 m/year. Our analysis of 31 piezometric wells (P-Wells) from 2000 to 2022 reveals a downward monotonic (in 16 P-Wells) and nonmonotonic (in 12 P-Wells) trend in groundwater table changes. Moreover, the GW table in the P-Wells near the river depends entirely on river flow. Furthermore, our findings indicate that river regulation exerts a dominant role in the control of land subsidence. Consequently, when water flows in the Zayandeh-Rud River, the rate of land subsidence declines significantly, particularly in urban regions. Therefore, maintaining a constant flow of water in the river can prevent or reduce ongoing land subsidence in Isfahan.

Using Sentinel-2 data to estimate the concentration of heavy metals caused by industrial activities in Ust-Kamenogorsk, Northeastern Kazakhstan.

This study aims to investigate the change in heavy metal concentration and evaluate pollution intensity using Sentinel-2 data. Sixty samples collected from the surface soil in the area were used to determine the concentration of lead, copper, and zinc using atomic absorption spectroscopy. Then, the step-by-step regression method was used in ArcGIS software to determine the relationship between the concentration of heavy metals and the ranking of the influential spectral bands of Sentinel-2 to monitor heavy metals in the relevant sampling points. According to the results, lead monitoring was effective through the blue channel, the ratio of green to near infrared-IV channels, and the ratio of short-wave infrared-III to near infrared-II channels. At the same time, copper was monitored through reflectance values in the red channel, the ratios of green to near infrared-IV channels, and the ratio of short-wave infrared-III to near infrared-II channels. The blue channel and the ratio of green to near infrared-IV channels the ratio of near infrared-II to near infrared-IV channels were efficient for zinc monitoring. Pollution Load Indices (PLI) and Geographical Accumulation Index (Igeo) were calculated to classify the contaminated soils of the region. The efficiency of each relationship obtained was evaluated using the root mean square error (RMSE) and Pearson's correlation coefficient (R). In summary, the copper, lead, and zinc equations had RMSE values of 1.8, 2.5, and 1.60 mg/kg, respectively. The Pearson correlation coefficients (R) for copper, lead, and zinc were 0.80, 0.76, and 0.72, respectively, which indicated good agreement between measured and estimated values.

Uvulopalatopharyngoplasty with and without modified thyrohyoid suspension for obstructive sleep apnea treatment: a randomized clinical trial.

PURPOSE: This study aims to compare the efficacy of Uvulopalatopharyngoplasty + Tongue Base Radiofrequency (TB-RF) and Uvulopalatopharyngoplasty + modified thyrohyoid suspension techniques + TB-RF which aimed to suspend base of tongue muscles anteriorly toward thyroid cartilage. METHODS: This randomized controlled trial study was conducted on 48 cases of confirmed OSA between Jan, 2019 and Aug, 2022. We divided patients into two groups. One group underwent Uvulopalatopharyngoplasty + modified thyrohyoid suspension + TB-RF technique, and another one underwent Uvulopalatopharyngoplasty + TB-RF. Then, Apnea-Hypopnea Index (AHI), mean and lowest O2 saturation, Drug-Induced Sleep Endoscopy (DISE), Epworth Sleepiness Scale (ESS), Digit Symbol Substitution Test (DSST), Stanford Subjective Snoring Scale (SSSS), and T90 indexes were evaluated before and after each surgery. RESULTS: The mean ± SD age was 39.4 ± 11.17 years. Of the 48 patients, 79.1% (n = 33) were male and 20.9% (n = 15) were female. AHI and SSSS in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension group were significantly better than Uvulopalatopharyngoplasty group (P-value; 0.010). Though, there was no significant difference in terms of mean saturation, lowest desaturation, ESS, DSST, and T90 scores. The success rate in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension and Uvulopalatopharyngoplasty groups, according to the Sher criteria: a minimum of 50% reduction with a final AHI less than 20, were 75% (18/24) and 41.7% (10/24), respectively. It was significantly higher in the Uvulopalatopharyngoplasty + modified thyrohyoid suspension group (P-value: 0.021). CONCLUSION: The addition of modified thyrohyoid suspension technique to Uvulopalatopharyngoplasty have better surgical outcomes and more success rate than Uvulopalatopharyngoplasty in OSA patients. TRIAL REGISTRATION: IRCT: IRCT20190602043791N2. https://en.irct.ir/trial/53365 .

Management of eagle syndrome.

PURPOSE OF REVIEW: Eagle syndrome is a challenging clinical presentation with important potential complications. It can be misdiagnosed due to lack of awareness; this review provides information in terms of diagnosis and management of eagle syndrome. RECENT FINDINGS: The importance of early diagnosis of this rare disease is preventing the delay in clinical-surgical treatment. As there is not a universally accepted cut-off for styloid process length, the diagnosis should be confirmed by length of process greater than one-third of the length of mandibular ramus in addition to other clinical symptoms and signs. There are both surgical and pharmacological treatment options for these patients. SUMMARY: Eagle syndrome is a rare clinical condition and its diagnosis is made by physical examination and radiography. When it is suspected by physical examination, definitive diagnosis is confirmed by computed tomography scans of the skull, as the gold standard. Location, degree of elongation of styloid process, and severity and reproducibility of symptoms are important factors in deciding the most appropriate approach. Surgery is frequently the treatment of choice in Eagle syndrome patients. With proper diagnosis and treatment, the prognosis is favourable and recurrence is uncommon.

Optimization of 4D Flow MRI Spatial and Temporal Resolution for Examining Complex Hemodynamics in the Carotid Artery Bifurcation.

BACKGROUND: Three-dimensional, ECG-gated, time-resolved, three-directional, velocity-encoded phase-contrast MRI (4D flow MRI) has been applied extensively to measure blood velocity in great vessels but has been much less used in diseased carotid arteries. Carotid artery webs (CaW) are non-inflammatory intraluminal shelf-like projections into the internal carotid artery (ICA) bulb that are associated with complex flow and cryptogenic stroke. PURPOSE: Optimize 4D flow MRI for measuring the velocity field of complex flow in the carotid artery bifurcation model that contains a CaW. METHODS: A 3D printed phantom model created from computed tomography angiography (CTA) of a subject with CaW was placed in a pulsatile flow loop within the MRI scanner. 4D Flow MRI images of the phantom were acquired with five different spatial resolutions (0.50-2.00  mm3) and four different temporal resolutions (23-96 ms) and compared to a computational fluid dynamics (CFD) solution of the flow field as a reference. We examined four planes perpendicular to the vessel centerline, one in the common carotid artery (CCA) and three in the internal carotid artery (ICA) where complex flow was expected. At these four planes pixel-by-pixel velocity values, flow, and time average wall shear stress (TAWSS) were compared between 4D flow MRI and CFD. HYPOTHESIS: An optimized 4D flow MRI protocol will provide a good correlation with CFD velocity and TAWSS values in areas of complex flow within a clinically feasible scan time (~ 10 min). RESULTS: Spatial resolution affected the velocity values, time average flow, and TAWSS measurements. Qualitatively, a spatial resolution of 0.50  mm3 resulted in higher noise, while a lower spatial resolution of 1.50-2.00  mm3 did not adequately resolve the velocity profile. Isotropic spatial resolutions of 0.50-1.00  mm3 showed no significant difference in total flow compared to CFD. Pixel-by-pixel velocity correlation coefficients between 4D flow MRI and CFD were > 0.75 for 0.50-1.00  mm3 but were < 0.5 for 1.50 and 2.00  mm3. Regional TAWSS values determined from 4D flow MRI were generally lower than CFD and decreased at lower spatial resolutions (larger pixel sizes). TAWSS differences between 4D flow and CFD were not statistically significant at spatial resolutions of 0.50-1.00  mm3 but were different at 1.50 and 2.00 mm3. Differences in temporal resolution only affected the flow values when temporal resolution was > 48.4 ms; temporal resolution did not affect TAWSS values. CONCLUSION: A spatial resolution of 0.74-1.00  mm3 and a temporal resolution of 23-48 ms (1-2 k-space segments) provides a 4D flow MRI protocol capable of imaging velocity and TAWSS in regions of complex flow within the carotid bifurcation at a clinically acceptable scan time.

Hemodialysis and peritoneal dialysis-health-related quality of life: systematic review plus meta-analysis.

BACKGROUND: Patients with end-stage renal disease undergoing haemodialysis experience a variety of stressors leading to decreased level of quality of life (QoL). Thus, in this study, we aimed to review the current literature and identify factors affecting the health-related QoL (HRQoL) in these patients. METHODS: A total of 147 studies were extracted from databases of Web of Science, PubMed, Scopus, Google Scholar, and Embase published between January 2000 and December 2020. Data were analysed using R software and results were reported with reference to Preferred Reporting Items for Systematic Reviews and Meta-Analyses standards. RESULTS: A total of 623 728 patients undergoing dialysis participated in 147 studies in which QoL was assessed by means of two valid questionnaires, including Short-Form 36 (SF-36) and Kidney Disease Quality of Life (KDQOL)-short form V.1.3. Total HRQoL score for patients undergoing dialysis measured by KDQOL was 64.25 (95% CI 55.67 to 72.82). Based on SF-36, the mean score of mental health items was higher than the mean score of physical health condition. Furthermore, meta-regression based on the geographical place of residence revealed that the highest QoL in patients was observed in Japan, 66.96 (95% CI 63.65 to 70.28) and Brazil, 58.03 (95% CI 53.45 to 62.6). CONCLUSION: Studies conducted on HRQoL among patients undergoing dialysis recommend useful strategies to clinicians, letting them assess patients' QoL in terms of a wide range of physical, mental and environmental aspects.

Global systematic review and meta-analysis of health-related quality of life in Behcet's patients.

Background: Behcet's disease (BD) is a chronic fatal illness with a relapsing remitting nature and significant organ-threatening morbidity and mortality. The aim of this research was to examine studies which were conducted on investigation of prevalence of quality of life among patients with Behcet's disease. Methods: A total of 13 articles were extracted from four main databases including PubMed, EMBASE, Scopus, and Web of Science from the onset of 2000 to January 2021. All studies published in English with the purpose of examining quality of life (QOL) among patients with BD or investigating its main determinants were included. Results: Totally, 1137 BD patients participated in 13 studies. Based on random effect analysis, the total score of physical health-related QOL was 46.7 (95% CI=41.26 to 52.13) and the total score of mental health-related QOL was 49.01 (95% CI=43.83 to 54.18) representing a moderate level of QOL among BD patients. Furthermore, weighted effect size analyses showed a significant correlation between QOL and variables such as patients' age, gender, disease duration and depression (pvalue: 0.00). Conclusion: As the symptoms of BD worsen over time, patients confront with more severe body pain, mobility restrictions, and difficulties in chewing, eating, speaking and swallowing which negatively affect social interactions of patients and reduce their QOL. Furthermore, depression was proved to act as a deteriorating factor for Health-Related Quality of Life (HRQOL) among BD patients. Thus, patients need to be psychologically supported by a specialized team and be informed during the course of treatment to gain useful information about the disease, treatment approaches and coping strategies.

Flow assessment as a function of pump timing of tubular pulsatile pump for use as a ventricular assist device in a left heart simulator.

INTRODUCTION: Although mechanical circulatory support saved many lives during the last decade, clinical observations have shown that the continuous flow pumps are associated with a much higher incidence of gastrointestinal bleeding and kidney problems, among others, compared with the earlier generation pulsatile pumps. However, the presence of several moving mechanical components made pulsatile pumps less durable, bulky, and prone to malfunction, ultimately leading to bias in favor of continuous flow designs. OBJECTIVE: The aim of the current work is to create a prototype tubular pulsatile pump and to test the timing of the pump in a left heart simulator. METHODS: A left heart simulator to mimic pumping from a failing heart was created. This was used to experimentally test the output of a prototype ventricular assist device relative to a failing heart in the form of flow and pressure. The effect of pulsation timing was quantified. RESULTS: A failing heart was simulated with an average flow rate of 1.1 L/min and a systolic pressure of 47 mm Hg. With the pump, the flow rate increases to 4.8 L/min and a systolic pressure of 110 mm Hg, in a copulsation mode, while activating for 300-400 ms. If the activation time is reduced, or increased, the pump becomes less effective. Load on the heart is reduced when the pump operates in a counterpulsation mode. CONCLUSION: A pulsatile pump, like the one proposed, provides adequate output for mechanical circulatory support, while minimizing the number of moving parts that could otherwise lead to tribological wear.

Simultaneous improvements in antibacterial and flame retardant properties of PET by use of bio-nanotechnology for fabrication of high performance PET bionanocomposites.

Recently, attentions to the applications of biotechnology and nanotechnology in the polymer industries have been greater than before. Hybrid nanocomposites containing multi-type of nano structures are widely established, but application of biotechnology for in-situ embedment of nanoparticles in polymer matrix is rarely reported. In this study, poly (ethylene terephthalate) (PET) based ternary bionanocomposites containing modified chitosan (phosphorylated chitosan) and nanosilver particles were prepared by simple eco-friendly method. Chitosan was selected as a biopolymer with respect to the biological activity and compatibility with PET. Phosphorylation of chitosan was achieved in order to introduce the phosphorus moieties as a flame retardant agent in PET matrix by using chemical approach. Also a cost-effective and environmentally friendly method was used for the in-situ fabrication and decoration of silver nanoparticles on to phosphorylated chitosan in PET matrix. Effects of the hybrid system (phosphorylated chitosan and silver nanoparticles) on the morphology, thermal behavior and antibacterial properties of the PET samples were investigated by different methods. The microstructure and homogeneity of the samples were analyzed by studying of dispersion of nanoparticles in PET via scanning electron microscopy. The antibacterial properties of PET nanocomposites can be improved by insertion of silver nanoparticles into the bulk of polymer matrix. Obtained results indicated that the PET/phosphorylated chitosan/silver nanocomposites showed a significantly higher growth inhibition rate compared with the PET and PET/phosphorylated chitosan blend. Also the flame retardant properties of PET nanocomposites were drastically enhanced.

Valveless pumping behavior of the simulated embryonic heart tube as a function of contractile patterns and myocardial stiffness.

During development, the heart begins pumping as a valveless multilayered tube capable of driving blood flow throughout the embryonic vasculature. The mechanical properties and how they interface with pumping function are not well-defined at this stage. Here, we evaluate pumping patterns using a fluid-structure interaction computational model, combined with experimental data and an energetic analysis to investigate myocardial mechanical properties. Through this work, we propose that a myocardium modeled as a Neo-Hookean material with a material constant on the order of 10 kPa is necessary for the heart tube to function with an optimal pressure and cardiac output.

Comparing the Accuracy of Ohmann and Alvarado Scoring Systems in Detection of Acute Appendicitis; a Cross-Sectional Study.

INTRODUCTION: Alvarado Scoring System (ASS) and Ohmann Scoring System (OSS) are two scoring systems for diagnosing acute appendicitis (AA). This study was designed to compare the diagnostic accuracy of the two mentioned scores in detection of acute abdominal cases at risk for AA. METHODS: In this prospective cross-sectional study, patients admitted to the emergency departments of two academic hospitals in Qom, Iran, with right lower quadrant (RLQ) abdominal pain suspected to AA were evaluated. All cases were scored using ASS and OSS, and screening performance characteristics of the two scores were calculated and reported considering the pathologic findings as a gold standard. RESULTS: 174 patients with a preliminary AA diagnosis and the mean age of 38.1 ± 10.63 years (11- 73) were included in this study (62.07% male). At the optimal cutoff point of ≥7 for the ASS, the sensitivity and the specificity were 46.43% (95% CI: 37.97%-55.07%), 97.05% (95% CI: 84.67%-92.93%), respectively. At the optimal cutoff point of ≥11 for the OSS, the sensitivity and the specificity were 74.29% (95% CI: 66.22%-81.29%), and 55.88% (95% CI: 37.89% - 72.82%), respectively. CONCLUSION: Based on the finding of this study, the ASS ≥ 7 was more accurate than the OSS ≥ 11 for detection of AA. But it should be considered that the overall accuracy of Alvarado and Ohmann scores in this regard were fair (0.83) and poor (0.67), respectively.

Battling Water Limits to Growth: Lessons from Water Trends in the Central Plateau of Iran.

The Zayandeh-Rud River Basin in the central plateau of Iran continues to grapple with water shortages due to a water-intensive development path made possible by a primarily supply-oriented water management approach to battle the water limits to growth. Despite inter-basin water transfers and increasing groundwater supply, recurring water shortages and associated tensions among stakeholders underscore key weaknesses in the current water management paradigm. There was an alarming trend of groundwater depletion in the basin's four main aquifers in the 1993-2016 period as indicated by the results of the Mann-Kendall3 (MK3) test and Innovative Trend Analysis (ITA) of groundwater volume. The basin's water resources declined by more than 6 BCM in 2016 compared to 2005 based on the equivalent water height (EWH) derived from monthly data (2002-2016) from the GRACE. The extensive groundwater depletion is an unequivocal evidence of reduced water availability in the face of growing basin-wide demand, necessitating water saving in all water use sectors. Implementing an integrated water resources management plan that accounts for evolving water supply priorities, growing demand and scarcity, and institutional changes is an urgent step to alleviate the growing tensions and preempt future water insecurity problems that are bound to occur if demand management approaches are delayed.

Clinical Characteristics of COVID-19 Patients with Gastrointestinal Symptoms.

BACKGROUND: We aimed to assess the gastrointestinal (GI) manifestations of patients with severe acute respiratory syndrome coronavirus 2 infection and determine factors predicting disease prognosis and severity among patients with GI symptoms. METHODS: In this retrospective study, we evaluated laboratory confirmed (by real-time polymerase chain reaction) inpatient cases of coronavirus-associated disease 2019 (COVID-19), referred to Sina hospital, a tertiary educational hospital of Tehran University of Medical Sciences, from March 10 to May 20, 2020. Demographic and clinical characteristics, laboratory data, outcomes and treatment data were extracted and analyzed using SPSS version 20. RESULTS: A total of 611 patients (234 women and 377 men) were included with 155 patients having GI symptoms. The most prevalent reported GI symptom was nausea/vomiting in 115 (18.8%) of patients. A total of 20 patients (3.2%) only had GI symptoms (without respiratory symptoms). There was no statistically significant difference in the clinical outcomes, disease severity, intensive care unit (ICU) admission and mortality between patients with and without GI symptoms. Aspartate Aminotransferase level was associated with 446% increased risk of disease severity (adjusted odds ratio: 5.46, 95% CI: 2.01 to 14.81) (P=0.040) among patients with GI symptoms. Additionally, we found that treatment with antibiotics in addition to mechanical ventilation was associated with increased survival among patients with GI symptoms (Pearson Chi square: 6.22; P value: 0.013). CONCLUSION: More attention should be paid to patients with only GI symptoms for early patient detection and isolation. Moreover, patients with GI manifestations are not exposed to higher rates of disease severity or mortality.

Yield prediction with machine learning algorithms and satellite images.

BACKGROUND: Barley is one of the strategic agricultural products available in the world, and yield prediction is important for ensuring food security. One way of estimating a product is to use remote sensing data in conjunction with field data and meteorological data. One of the main issues surrounding this comprises the use of machine learning techniques to create a multi-resource data-based estimation model. Many studies have been conducted on barley yield prediction from planting to harvest. Still, the effect of different time intervals on yield prediction has not been investigated. Furthermore, the effect of different periods on yield prediction has not been investigated. RESULTS: In the present study, the whole growth period was divided into three parts. Using one of the major barley production areas in Iran, the performance of the proposed model was evaluated. In the first step, a model for integrating field data, remote sensing data and meteorological data was prepared. The results obtained show that, among the four machine learning methods implemented, the gaussian process regression algorithm performed best and estimated yield with r2 = 0.84, root mean square error = 737 kg ha-1 and mean absolute = 650 kg ha-1 , 1 month before harvest. CONCLUSION: It was found that the estimation results change depending on different agricultural zones and temporal training settings. The findings of the present study provide a powerful potential tool for the yield prediction of barley using multi-source data and machine learning. © 2020 Society of Chemical Industry.

Pathologic Shear and Elongation Rates Do Not Cause Cleavage of Von Willebrand Factor by ADAMTS13 in a Purified System.

INTRODUCTION: Pathological flows in patients with severe aortic stenosis are associated with acquired von Willebrand syndrome. This syndrome is characterized by excessive cleavage of von Willebrand factor by its main protease, A Disintegrin and Metalloproteinase with a Thrombospondin Type 1 Motif, Member 13 (ADAMTS13) leading to decreased VWF function and mucocutaneous bleeding. Aortic valve replacement and correction of the flow behavior to physiological levels reverses the syndrome, supporting the association between pathological flow and acquired von Willebrand syndrome. We investigated the effects of shear and elongational rates on von Willebrand factor cleavage in the presence of ADAMTS13. METHODS: We identified acquired von Willebrand syndrome in five patients with severe aortic stenosis. Doppler echography values from these patients were used to develop three computational fluid dynamic (CFD) aortic valve models (normal, mild and severe stenosis). Shear, elongational rates and exposure times identified in the CFD simulations were used as parameters for the design of microfluidic devices to test the effects of pathologic shear and elongational rates on the structure and function of von Willebrand factor. RESULTS: The shear rates (0-10,000s-1), elongational rates (0-1000 s-1) and exposure times (1-180 ms) tested in our microfluidic designs mimicked the flow features identified in patients with aortic stenosis. The shear and elongational rates tested in vitro did not lead to excessive cleavage or decreased function of von Willebrand factor in the presence of the protease. CONCLUSIONS: High shear and elongational rates in the presence of ADAMTS13 are not sufficient for excessive cleavage of von Willebrand Factor.

Remotely sensed vegetation indices for crop nutrition mapping.

BACKGROUND: Spectral reflectance measurements and vegetation indices have been used widely to monitor plant nutritional status. Remote sensing methods are very fast, convenient, and non-destructive techniques for estimating crop nutrition indices. With the rapid development of remote sensing satellites, unmanned aerial vehicles, and the Internet of Things, remote sensing will increasingly be used in crop nutrition diagnosis. This can lead to lower operating costs for fertilization and can minimize loss of productivity. RESULTS: In this study, satellite images were used for 2 years to evaluate the use of vegetation indices for crop nutrition mapping, in two regions, located in the cities of Ray and Karaj. For each farm, eight reference points in each year were selected to determine the crop nutrition status for model development and accuracy assessment. Then, ten spectral vegetation indices were used to calculate the crop nutrition content at mid-season and at the end of the season. The results indicated that transformed chlorophyll absorption in reflectance index (TCARI) and modified chlorophyll absorption in reflectance index (MCARI) had the highest R2 and the lowest RMSE values, respectively (R2 TCARI = 0.83, RMSETCARI = 12.47 kg ha-1 and R2 MCARI = 0.75 and RMSEMCARI = 14.47 kg ha-1 ). CONCLUSION: The performance of TCARI and MCARI was strong across the two farms and allowed the creation of highly accurate crop nutrition maps. In conclusion, the use of the near infra-red and red-edge bands in mid-season led to better results than vegetation indices calculated at the end of the season or that do not included the red-edge band. © 2020 Society of Chemical Industry.