A Cyclic Pursuit Framework for Networked Mobile Agents Based on Vector Field Approach

This paper proposes a pursuit formation control scheme for a network of double-integrator mobile agents based on a vector field approach. In a leaderless architecture, each agent pursues another one via a cyclic topology to achieve a regular polygon formation. On the other hand, the agents are exposed to a rotational vector field such that they rotate around the vector field centroid, while they keep the regular polygon formation. The main problem of existing approaches in the literature for cyclic pursuit of double-integrator multiagent systems is that under those approaches, the swarm angular velocity and centroid are not controllable based on missions and agents capabilities. However, by employing the proposed vector field approach in this paper, while keeping a regular polygon formation, the swarm angular velocity and centroid can be determined arbitrary. The obtained results can be extended to achieve elliptical formations with cyclic pursuit as well. Simulation results for a team of eight mobile agents verify the accuracy of the proposed control scheme

An H {592}[infinity] dynamic routing control of networked multi-agent systems

This research aims to introduce an analytical solution to the routing problem of Networked Multi-Agent Systems (NMAS) by taking advantage of control theory machinery. Routing problem can be defined as that of finding a route for messages among networked agents by adjusting the output flow of each link according to the traffic information of the network, such that some objective functions are minimized. In this research, a new objective function, namely worst-case queueing length is introduced based on which a novel routing methodology is presented. The propagating, transmitting and processing delays are inevitable characteristics of the queueing dynamics which is considered in the model of the network. The proposed dynamic optimization problem is formulated as a feedback control problem. First, a centralized [Special characters omitted.] optimal control scheme is proposed which can maintain a robust performance of the routing strategy in the presence of multiple and unknown time-varying delays for a fixed network topology. The routing problem is formulated as an [Special characters omitted.] optimal control problem for a time-delayed system. The resulting optimization problem is then recast as a minimization problem involving Linear Matrix Inequality (LMI) constraints. The physical constraints are also formulated as LMI feasibility conditions. The proposed centralized routing scheme is then reformulated in a decentralized framework. This modification yields an algorithm that, obtains the "fastest route", provides robustness against multiple unknown time-varying delays, and enhances the scalability of the algorithm to large scale traffic networks. By stochastically changing the network topology due to the nodes' mobility the overall network model is described by a Markovian jump process. The proposed Markovian jump dynamics can also support changing number of nodes due to adding new nodes to the network or deleting them because of their low energy or faults/failures. The resulting problem which involves Markovian jump dynamics due to the time-varying delays appearing in control is more challenging to solve. The problem is further complicated by the fact that the interconnected terms also change at each switching mode. To stabilize this system, an [Special characters omitted.] controller is presented for the Markovian jump system for mode-dependent interconnected terms. Finally, the LMIs corresponding to the associated physical constrains are properly modified for the mobile networks

A Decentralized Markovian Jump {cal H}_{\infty } Control Routing Strategy for Mobile Multi-Agent Networked Systems

This paper presents a Markovian jump linear (MJL) system framework for developing routing algorithms in mobile ad hoc networks (MANETs) that encounter changes in the number of nodes and/or the number of destinations. A unified H∞ control strategy is proposed by representing the dynamically changing destination nodes as singular switching control systems. A decentralized routing scheme is proposed and designed for the networked multi-agent system in presence of unknown time-varying delays. To solve the corresponding optimization problem the physical constraints are expressed as linear matrix inequality (LMI) conditions. The resulting decentralized H∞ routing control schemes for both regular and singular MJL systems are shown to formally achieve the desired performance specifications and requirements. Simulation results are presented to illustrate and demonstrate the effectiveness of our proposed novel routing control strategies

Protective effect of date palm pollen (<em>Phoenix dactylifera)</em> on sperm parameters and sexual hormones in male NMRI mice exposed to low frequency electromagnetic field (50 Hz)

Introduction: Exposure to electromagnetic fields (EMFs) induces harmful effects on testis and reproductive activities. In traditional medicine, date palm pollen (DPP) which has remarkable nutritional values is used for curing male infertility and impotency. The aim of this study was to investigate the protective effect of DPP in preventing the detrimental effects of low frequency electromagnetic field (50 Hz) on sperm parameters and sexual hormones. Methods: Adult male mice were randomly divided into 7 groups of 8 and exposed to EMF 4 h/day for 10 days. In this study experimental groups received DPP with doses of 25, 50, 100 and 200 mg/kg, respectively before exposure. At the end of the experiment each group were tested for sperm parameters including: motility, count, morphology, viability and the level of luteinizing hormone (LH) and testosterone. Results: Our results revealed that exposure to EMF induced significant reduction (P &lt; .001) in sperm count, viability and progressive motility in comparison with control group. EMF caused abnormalities in sperm and significant decrease in testosterone level while there was no significant difference in level. Administration of DPP before exposure improved the sperm count, viability, motility and testosterone level in experimental groups. In addition, pretreatment with DPP prevented the sperm abnormality induced by EMF. Conclusion: The results indicate the protective effect of DPP against EMF adverse effects on sperm parameters and sexual hormones in male mice.</p

Effect of Phoenix dactylifera pollen grain on maturation of preantral follicles in NMRI mice

Introduction: Optimizing an ideal culture system that is comparable to follicle environment to obtain mature oocytes is one of the important criteria in in vitro maturation (IVM). Phoenix dactylifera L. commonly known as date palm is an important herb in Asia folk medicine that is used to improve fertility in women from ancient time. The aim of this study was to investigate the effect of date palm pollen grain extract on IVM of mouse follicles. Methods: In this study follicles with 1 or 2 layers of granulosa cells and round oocytes were isolated from 2-3 weeks old female NMRI mice ovaries. Follicles were cultured in IVM media with different concentrations 0, 10, 20, 30, 40 &mu;g/ml of palm pollen grain extract for 12 days. Then, the effect of date palm pollen grain on follicular growth and maturation were analyzed. Results: There was a significant increase in follicle growth and maturation rate in all treated groups as compared to the control group, but maturation rate was significantly higher in the presence of 20 &mu;g/ml palm pollen grain. Conclusion: Supplementation of IVM media with date palm pollen grain extract improves the IVM of follicles.</p

Vestibular Migraine: from Differential Diagnosis and Pathophysiology to Treatment Options

Background: The occurrence of migraine and vertigo is common in the general population. Migraine vertigo is challenging and has several common symptoms with inner ear pathologies like Endolymphatic Hydropse. This paper presents a review of recent findings about symptoms, test results, pathophysiology and differential diagnosis. Methods: The present study is a review of 35 papers in the field of vestibular migraine. They were selected by searching the keywords vertigo, dizziness, migraine, treatment and rehabilitation in Pubmed, ScienceDirect, Scopus and Google Scholar search engines. Only human studies were included. Results: Recent findings have proposed several common pathophysiologies between vestibular system and migraine including spreading depression in the basilar artery, vasospasm in the internal auditory artery, involvement of the connection with locus coeruleus, dorsal raphe nucleus, disorder of multisensory integration and channelopathy. Conclusion: For the differential diagnosis of vestibular migraine, it appears that comprehensive case history as well as clinical testing and patient followup, are the best combination. In addition, it has been proven that vestibular rehabilitation is beneficial to patients with vestibular migraine

Developing the Persian Version of Infant-Toddler Meaningful Auditory Integration Scale

Objectives: Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS) is a useful tool for the quantitative evaluation of auditory behaviors in different situations. The present study aimed to develop the Persian version of IT-MAIS. Methods: There was 4 main steps in the translation and validation of the scale, as follows: forward translation, synthesis, backward translation, and expert committee discussion. Then, the final Persian version of the scale was analyzed in terms of reliability and validity. The scale was studied on the parents of 17 hearing impaired and 17 normal hearing children. Results: There was a significant difference in the mean score of scale between hearing impaired and normal hearing children (P≤0.001). The internal consistency of the items was satisfactory. The Cronbach’s alpha for the overall score was 0.93. Discussion: This study suggested that IT-MAIS-F can be a reliable and valid tool for the evaluation of the auditory function of children. However, the sample size of the study was small. Thus, studies with larger sample sizes are recommended. In addition, test-retest reliability of the scale was not studied

Blood Lead Levels in Asymptomatic Opium Addict Patients; a Case Control Study

Introduction: One of the newest non-occupational sources of lead contamination is drug addiction, which has recently been addressed as a major source of lead poisoning in some countries. The present study aimed to investigate the blood lead level (BLL) of asymptomatic opium addicts.Methods: This case-control study was conducted during a one-year period to compare BLL of three groups consisting of opium addicts, patients under methadone maintenance therapy (MMT), and healthy individuals.Results: 99 participants with the mean age of 55.43±12.83 years were studied in three groups of 33 cases (53.5% male). The mean lead level in opium addicts, MMT and control groups were 80.30 ± 6.03 μg/L, 67.94 ± 4.42 μg/L, and 57.30±4.77 μg/L, respectively (p=0.008). There was no significant difference in BLL between MMT and healthy individuals (p=0.433) and also between opium addicts and MMT individuals (p=0.271).Oral opium abusers had significantly higher lead levels (p = 0.036). There was a significant correlation between BLL and duration of drug abuse in opium addict cases (r=0.398, p=0.022). The odds ratio of having BLL ≥ 100 in oral opium users was 2.1 (95% CI: 0.92 - 4.61; p = 0.43).Conclusion:  Based on the result of present study, when compared to healthy individuals, opium addicts, especially those who took substance orally had significantly higher levels of blood lead, and their odds of having BLL ≥ 100 was two times. Therefore, screening for BLL in opium addicts, particularly those with non-specific complaints, could be useful

Effect of Phoenix dactylifera pollen grain on maturation of preantral follicles in NMRI mice

Introduction: Optimizing an ideal culture system that is comparable to follicle environment to obtain mature oocytes is one of the important criteria in in vitro maturation (IVM). Phoenix dactylifera L. commonly known as date palm is an important herb in Asia folk medicine that is used to improve fertility in women from ancient time. The aim of this study was to investigate the effect of date palm pollen grain extract on IVM of mouse follicles. Methods: In this study follicles with 1 or 2 layers of granulosa cells and round oocytes were isolated from 2-3 weeks old female NMRI mice ovaries. Follicles were cultured in IVM media with different concentrations 0, 10, 20, 30, 40 μg/ml of palm pollen grain extract for 12 days. Then, the effect of date palm pollen grain on follicular growth and maturation were analyzed. Results: There was a significant increase in follicle growth and maturation rate in all treated groups as compared to the control group, but maturation rate was significantly higher in the presence of 20 μg/ml palm pollen grain. Conclusion: Supplementation of IVM media with date palm pollen grain extract improves the IVM of follicles

Nutritional knowledge, attitude and practice of Iranian households and primary health care staff: NUTRIKAP survey

The aim of this study is to determine knowledge, attitude and practice of Iranian households and health staff on nutrition at province level. The sampling method in NUTRIKAP survey for households in each province is singlestage cluster sampling and the size of clusters is equal. The sampling method for health staff in each province is stratified random sampling. Samples are selected from physicians, health experts, health technicians, nutritionists and health assistants (Behvarz). Overall, 14136 people in 57 clusters in each province and 480 health staff over the country participate in this survey. The necessary data will be gathered by the structured questionnaire and the interview with the eligible person in each household. Data gathering from health staff will be carried out by selfadministered questionnaire. The results of this study can help the bureau of community nutrition to provide the proper interventions to improve nutritional health of households