Land & Localize: An Infrastructure-free and Scalable Nano-Drones Swarm with UWB-based Localization

Relative localization is a crucial functional block of any robotic swarm. We address it in a fleet of nano-drones characterized by a 10 cm-scale form factor, which makes them highly versatile but also strictly limited in their onboard power envelope. State-of-the-Art solutions leverage Ultra-WideBand (UWB) technology, allowing distance range measurements between peer nano-drones and a stationary infrastructure of multiple UWB anchors. Therefore, we propose an UWB-based infrastructure-free nano-drones swarm, where part of the fleet acts as dynamic anchors, i.e., anchor-drones (ADs), capable of automatic deployment and landing. By varying the Ads' position constraint, we develop three alternative solutions with different trade-offs between flexibility and localization accuracy. In-field results, with four flying mission-drones (MDs), show a localization root mean square error (RMSE) spanning from 15.3 cm to 27.8 cm, at most. Scaling the number of MDs from 4 to 8, the RMSE marginally increases, i.e., less than 10 cm at most. The power consumption of the MDs' UWB module amounts to 342 mW. Ultimately, compared to a fixed-infrastructure commercial solution, our infrastructure-free system can be deployed anywhere and rapidly by taking 5.7 s to self-localize 4 ADs with a localization RMSE of up to 12.3% in the most challenging case with 8 MDs

Variable Rate Low Density Parity Check Decoder

A method includes receiving a first data frame and a second data frame from a communication channel; decoding the first data frame using a first portion of an extended parity-check matrix (PCM); and decoding the second data frame using a second portion of the extended PCM. The first portion is a subset of the second portion.U

The relationship between maladaptive schemas, perfectionism, and self-expression with students\' tendency to substance abuse

Background and Aim: The present study investigated the relationship between maladaptive schemas, perfectionism, and self-expression with a tendency to substance abuse in students. Methods: The present study was a descriptive correlational study, and the statistical population included all students of Islamic Azad University, Saveh Branch, in 2015. The statistical population included 8754 people, in which 360 people were selected using stratified random sampling method and based on the Morgan table. Then, they were examined by the questionnaire of Jung (1990) maladaptive schemas, Frost (1990) perfectionism, Gay self-expression (1975), and Substance abuse trend questionnaire of Farhad et al. (2006). Results: Findings showed that there is a positive relationship between early maladaptive schemas with a tendency to substance abuse and perfectionism, and there is a significant negative relationship between self-expression and a tendency to substance abuse among students. Regression coefficients also showed that the variable of perfectionism with a beta coefficient of 0.34, the variable of early maladaptive schemas in the field of disturbed constraint with a beta coefficient of 0.29, and the variable of early maladaptive schemas in terms of disconnection and exclusion with a beta coefficient of 0.24 can positively predict students' tendency to substance abuse. And the variable of self-expression with a beta coefficient of 0.19 can negatively and significantly predict students' tendency to substance abuse. Conclusion: The results showed that the variables of perfectionism, early maladaptive schemas in the field of disrupted constraints, early maladaptive schemas in the field of disconnection and exclusion can predict the tendency to drug abuse

In vitro and in vivo antidiabetic activity of Tamarix stricta Boiss.: Role of autophagy

Ethnopharmacological relevance: Type 2 diabetes mellitus (DM) is a complicated metabolic disorder with no definite treatment. Different species of the genus Tamarix (tamarisk) are used by local people to treat DM. Tamarix stricta Boiss. is an endemic species to Iran with several traditional therapeutic uses in Persian Medicine. This study aimed to assess the antidiabetic activity of T. stricta. Materials and methods: Hydroethanolic extract of the plant was prepared and analyzed by High-performance liquid chromatography (HPLC). The protective effect of the extract was evaluated in streptozotocin (STZ)-induced toxicity and markers of autophagy in pancreatic RIN-5F cells. The effect of intragastric 10 or 20 mg/kg of the extract was compared with negative control (water) or positive control (metformin) treatment during four weeks of administration in high-fat diet + STZ-induced DM in Balb/c mice. Results: Results showed the presence of 8.436 mg of gallic acid in each gram of the extract. A significant cytoprotective effect was observed by T. stricta in STZ-induced toxicity in RIN-5F cells, partially due to the modulation of autophagy. Also, animals treated with the extract showed a significant improvement in glycemic and lipid profiles, liver function, and histopathologic features of pancreas and liver compared with the negative control. Conclusion: T. stricta demonstrated beneficial effects in animal model of DM; though, further studies are recommended to confirm the clinical use of this plant in DM. © 2020 Elsevier B.V

Phytochemical and toxicological evaluation of Tamarix stricta Boiss

The genus Tamarix includes several plant species well-known for their medicinal properties since ancient times. Tamarix stricta Boiss is a plant native to Iran which has not been previously investigated regarding its phytochemical and biological properties. This study assessed phytochemical and toxicological aspects of T. stricta. The plant was collected from Kerman province of Iran and after authentication by botanist, it was extracted with 70% ethanol. Total phenolic compounds, total flavonoids, and antioxidant properties were measured using spectrophometric methods. Quercetin content of the extract was measured after complete acid hydrolysis with high-performance liquid chromatography. The phytochemical profile of the extract was provided using liquid chromatography-mass spectrometry method. Acute toxicity study with a single intragastric dose of 5000 mg/kg of the extract and sub-chronic toxicity using 50, 100, and 250 mg/kg of the extract was assessed in Wistar rats. Phytochemical analysis showed that polyphenols constitute the major components of the extract. Also, the extract contained 1.552 ± 0.35 mg/g of quercetin. Biochemical, hematological, and histological evaluations showed no sign of toxicity in animals. Our experiment showed that T. stricta is a rich source of polyphenols and can be a safe medicinal plant. Further pharmacological evaluations are recommended to assess the therapeutic properties of this plant