Weak Alfvén-wave turbulence revisited

Weak Alfvénic turbulence in a periodic domain is considered as a mixed state of Alfvén waves interacting with the two-dimensional (2D) condensate. Unlike in standard treatments, no spectral continuity between the two is assumed, and, indeed, none is found. If the 2D modes are not directly forced, k−2 and k−1 spectra are found for the Alfvén waves and the 2D modes, respectively, with the latter less energetic than the former. The wave number at which their energies become comparable marks the transition to strong turbulence. For imbalanced energy injection, the spectra are similar, and the Elsasser ratio scales as the ratio of the energy fluxes in the counterpropagating Alfvén waves. If the 2D modes are forced, a 2D inverse cascade dominates the dynamics at the largest scales, but at small enough scales, the same weak and then strong regimes as described above are achieved

UB Robot Swarm System: Design and Implementation

In this poster we described the hardware architecture of an inexpensive, heterogeneous, mobile robot swarm, designed and developed at RISC lab, University of Bridgeport. Each UB robot swarm is equipped with sensors, actuators, control and communication units, power supply, and interconnection mechanism. Robot swarms have become a new research paradigm in the last ten years offering novel approaches, such as self-reconfigurabity, self-assembly, self-replication and self-learning. Developing a multi-agent robot system with heterogeneity and larger behavioral repertoire is a great challenge. This robot swarm is capable of performing user defined tasks such as wall painting, mapping, human rescue operations, task allocation, obstacle avoidance, and object transportation

Hardware Architecture Review of Swarm Robotics System: Self-Reconfigurability, Self-Reassembly, and Self-Replication

Swarm robotics is one of the most fascinating and new research areas of recent decades, and one of the grand challenges of robotics is the design of swarm robots that are self-sufficient. This can be crucial for robots exposed to environments that are unstructured or not easily accessible for a human operator, such as the inside of a blood vessel, a collapsed building, the deep sea, or the surface of another planet. In this paper, we present a comprehensive study on hardware architecture and several other important aspects of modular swarm robots, such as self-reconfigurability, self-replication, and self-assembly. The key factors in designing and building a group of swarm robots are cost and miniaturization with robustness, flexibility, and scalability. In robotics intelligence, self-assembly and self-reconfigurability are among the most important characteristics as they can add additional capabilities and functionality to swarm robots. Simulation and model design for swarm robotics is highly complex and expensive, especially when attempting to model the behavior of large swarm robot groups.http://dx.doi.org/10.5402/2013/84960

UBSwarm: Design of a Software Environment to Deploy Multiple Decentralized Robots

This article presents a high-level configuration and task assignment software package that distributes algorithms on a swarm of robots. The software allows the robots to operate in a swarm fashion. When the swarm robotic system adopts a decentralized approach, the desired collective behaviors emerge from local decisions made by the robots themselves according to their environment. Using its GUI, the proposed system expects the operator to select between several available robot agents and assign the swarm of robots a particular task from a set of available tasks

Foreign Direct Investment, Domestic Investment and Oil Price Nexus in Saudi Arabia

Foreign Direct Investment (FDI) inflows are targeted by every country to give external support to the economy and to fill saving-investment gap as well. This paper highlights the contributing factors of FDI inflows in Saudi Arabia by using annual data of 1970-2015 and by applying Auto-Regressive Distributive Lag (ARDL) cointegration methodology. This paper finds that Oil Price (OP) and Financial Market Development (FMD) are positively affecting to the FDI inflows. But, increasing Domestic Investment (DI) is found responsible for decreasing FDI inflows. Therefore, domestic investment can be considered as substitute for FDI inflows. This research recommends the Saudi government to promote FMD to support FDI inflows in Saudi Arabia and to diversify from oil dependence.   Keywords: FDI Inflows; Oil Price; Financial Market Development; Domestic Investment JEL Classifications: F21; F41; O1

Trade and Environment Nexus in Saudi Arabia: An Environmental Kuznets Curve Hypothesis

This research explores the effects of trade and income level on the Carbon Dioxide Emissions (CDE) in Saudi Arabia by using a period 1970-2016. Unit root and cointegration tests have been utilized for data analysis. Unit root test confirms the level of integration as one and cointegration has been found in our estimated model through bound testing procedure. In the long run, income is found responsible for increasing CDE but its square term is showing a negative impact on CDE. Therefore, this study has inveterate the presence of Environmental Kuznets Curve (EKC) hypothesis. Further, trade has negative impact on CDE. Therefore, trade has been remained helpful in reducing pollution levels in Saudi Arabia. The income, its square and trade have same directions of relationships in short run as in long run. Based on findings, this study recommends the Saudi government to liberalize trade policy to protect environment.        Keywords: Carbon Dioxide Emissions, Trade, Environmental Kuznets Curve JEL Classifications:  Q53, O49, Q56

UTJECAJ DULJINE IGS BAZE NA TOČNOST POZICIONIRANJA GNSS-A

Since the establishment of the International GNSS Service (IGS) stations, they have been used as control stations for assigning the Precise point positioning (PPP) positions using one Global Navigation Satellite System (GNSS) receiver, which has increased from day-to-day. There are some factors affecting the accuracy of PPP positioning. This research aims to investigate the relation between the IGS distance and observed field points as well as to attempt to describe that relation mathematically/statically. For the realization of that aim, two field points are fixed inside the Assiut University campus and observed successively for a session of 24 hour observation. The position of each field point is assigned with the help of each one of the available IGS station products. It must be known that these products are found after observations in three files (IGU, IGR, and final IGS), whereas IGU is used directly as real-time data (ultra-rapid), IGR (rapid) is used through (17-41 hours) after observation, and (final IGS) used after 12 – 18 days. Coordinates and point errors of each field points are computed and represented. It has been found that the errors have a positive relation with the available IGS stations distances. The relation between these distances and point positioning errors have been represented and described according to a model. The accuracy of the presented model is (R ≅ .98, x2 ≅ 2.5 × 10-3).Od uspostave postaja Međunarodnoga GNSS servisa (IGS) iz dana u dan povećava se korištenje kontrolnih stanica za dodjelu položaja precizne točke (PPP) pomoću jednoga prijamnika Globalnoga satelitskog navigacijskog sustava (GNSS). Postoje neki čimbenici koji utječu na točnost PPP pozicioniranja. Cilj je ovoga istraživanja istražiti odnos između IGS udaljenosti i promatranih točaka polja te opisati taj odnos matematički i statički. Za realizaciju toga cilja dvije terenske točke fiksirane su unutar kampusa Sveučilišta Assiut i promatrane sukcesivno tijekom sesije promatranja od 24 sata. Položaj svake točke polja dodjeljuje se uz pomoć svakoga od dostupnih proizvoda IGS stanica. Bitno je napomenuti da se ti produkti nalaze u tri datoteke (IGU, IGR i konačni IGS) nakon promatranja, dok se IGU koristi izravno kao podatci u stvarnome vremenu (ultra-rapid), IGR (rapid) kroz 17 – 41 sat nakon promatranja, a konačni IGS nakon 12 – 18 dana. Koordinate i pogreške točaka svake točke polja izračunane su i prikazane. Utvrđeno je da su pogreške u pozitivnom odnosu s dostupnim udaljenostima IGS postaja. Odnos između tih udaljenosti i pogrešaka pozicioniranja točke prikazan je i opisan prema modelu. Točnost je prikazanoga modela R ≅ .98, x2 ≅ 2.5 × 10-3

Study of Treg FOXP3 in childhood bronchial asthma in relation to corticosteroid therapy

Background: T cells are considered the main cells responsible for production of suppressive cytokines, and play a key role in balancing the immune responses to maintain the peripheral tolerance against allergens. Objective: The present study investigates T regulatory (Treg) forkheadwinged helix protein 3 FOXP3 expression in childhood asthma and its relation to corticosteroid therapy. Methods: In this case control study, Treg FOXP3 was measured in blood of 60 children using real time polymerase chain reaction (RT-PCR) technique. Two asthmatic groups were included, one on corticosteroid therapy (20 patients) and the other not on corticosteroid treatment (20 patients). They were compared to 20 healthy children as controls. Results: FOXP3 concentration was significantly elevated in asthmatic patients (90 ± 77.4) compared to healthy children (12.844 ± 10.6) (p= 0.000). FOXP3 was significantly more elevated in asthmatics on corticosteroids (161.158 ± 63.9) than steroid naive asthmatics (36.038 ± 23.4) (p=0.000). Levels of Treg FOXP3 in asthmatics with inhaled corticosteroids (mean 151.16 ± 53.79) were almost similar to FOXP3 in asthmatics with systemic corticosteroids (161.49±72.5) (p>0.05). FOXP3 levels did not differ with smoking, asthma severity or disease control and did not correlate with age, FEV1, blood lymphocytes percentage or eosinophils percentage. Conclusion: Asthmatics have increased expression of FOXP3, and corticosteroid therapy –whether oral or inhaled - enhances FOXP3 expression.Keywords: FOXP3, Treg, Corticosteroids, Bronchial asthma, Transcription factors, CytokinesEgypt J Pediatr Allergy Immunol 2012;10(1):39-43

Energy Consumption and Economic Growth: The Evidence from India

The oil price shock of the 1970s and its disruptive impact on the economic activities all over the world dragged the attention of researchers to study the interaction between energy and real output. However, no conclusive evidence could be submitted about the direction of causality between the two. The present study has been an attempt to understand such relationship in the case of India. The paper has used the data from 1971 to 2014 and has found long run stable relationship between energy use and real output. The study also reveals that in the short run, there is unidirectional relationship between the two and energy Granger causes economic activities in India. In the long run, we find bidirectional relationship between energy and economic prosperity of India. Keywords: Oil Consumption, Economic Growth, India. JEL Classifications: E20, E22, E31. DOI: https://doi.org/10.32479/ijeep.803