Compressed Sensing based Dynamic PSD Map Construction in Cognitive Radio Networks

In the context of spectrum sensing in cognitive radio networks, collaborative spectrum sensing has been proposed as a way to overcome multipath and shadowing, and hence increasing the reliability of the sensing. Due to the high amount of information to be transmitted, a dynamic compressive sensing approach is proposed to map the PSD estimate to a sparse domain which is then transmitted to the fusion center. In this regard, CRs send a compressed version of their estimated PSD to the fusion center, whose job is to reconstruct the PSD estimates of the CRs, fuse them, and make a global decision on the availability of the spectrum in space and frequency domains at a given time. The proposed compressive sensing based method considers the dynamic nature of the PSD map, and uses this dynamicity in order to decrease the amount of data needed to be transmitted between CR sensors’ and the fusion center. By using the proposed method, an acceptable PSD map for cognitive radio purposes can be achieved by only 20 % of full data transmission between sensors and master node. Also, simulation results show the robustness of the proposed method against the channel variations, diverse compression ratios and processing times in comparison with static methods

Preventive effect of vitamin B6 on developmental toxicity of carbamazepine in mice

Objective(s): Carbamazepine (CBZ) is an antiepileptic drug that is used widely for the treatment of epileptic seizures. Neural tube defects (NTDs), growth retardation, and nail hypoplasia are the most common features of teratogenic effects of this drug. The purpose of this study was to examine the effect of vitamin B6 on the developmental toxicity of CBZ on mice. Materials and Methods: Sixty BALB/c pregnant mice were divided into four experimental and two control groups. Two experimental groups received daily intraperitoneal injection (IP) of 30 mg/kg (I) or 60 mg/kg (II) of CBZ on gestational days (GD) 6 to 15. Two other experimental groups received daily IP injection of 30 mg/kg (III) or 60 mg/kg (IV) of CBZ with 10 mg/kg/day vitamin B6 by gavage 10 days prior to gestation and on GD 6 to 15. Two control groups received normal saline or Tween 20. Dams underwent Cesarean section on GD 18 and embryos were harvested. External/macroscopic observation of fetuses was done by stereomicroscope and external examination for malformations was recorded. Data analyzed by ANOVA and X 2 test using SPSS software. Results: The mean weight and crown-rump of the fetuses in both CBZ-treated experimental groups were significantly reduced compared with those of the control groups. Various malformations were detected such as brachygnathia, eye malformations, NTDs, vertebral deformity, brachydactyly and growth retardation. Vitamin B6 treatment significantly reduced various CBZ-induced malformations. Conclusion: This study showed that vitamin B6 has a preventive effect on the developmental toxicity of CBZ in mice that can be pursued further for clinical research

Holograms of Conformal Chern-Simons Gravity

We show that conformal Chern-Simons gravity in three dimensions has various holographic descriptions. They depend on the boundary conditions on the conformal equivalence class and the Weyl factor, even when the former is restricted to asymptotic Anti-deSitter behavior. For constant or fixed Weyl factor our results agree with a suitable scaling limit of topologically massive gravity results. For varying Weyl factor we find an enhancement of the asymptotic symmetry group, the details of which depend on certain choices. We focus on a particular example where an affine u(1) algebra related to holomorphic Weyl rescalings shifts one of the central charges by 1. The Weyl factor then behaves as a free chiral boson in the dual conformal field theory.Comment: 5

Synthesis of neural networks for spatio-temporal spike pattern recognition and processing

The advent of large scale neural computational platforms has highlighted the lack of algorithms for synthesis of neural structures to perform predefined cognitive tasks. The Neural Engineering Framework offers one such synthesis, but it is most effective for a spike rate representation of neural information, and it requires a large number of neurons to implement simple functions. We describe a neural network synthesis method that generates synaptic connectivity for neurons which process time-encoded neural signals, and which makes very sparse use of neurons. The method allows the user to specify, arbitrarily, neuronal characteristics such as axonal and dendritic delays, and synaptic transfer functions, and then solves for the optimal input-output relationship using computed dendritic weights. The method may be used for batch or online learning and has an extremely fast optimization process. We demonstrate its use in generating a network to recognize speech which is sparsely encoded as spike times.Comment: In submission to Frontiers in Neuromorphic Engineerin

Nature of intensity and phase modulations in stimulated Brillouin scattering

The nature of stimulated Brillouin scattering (SBS) temporal modulations for a focused beam in a finite-length cell with homogeneous medium is examined numerically. The finite phonon lifetime produces deterministic oscillations at the threshold while the inclusion of the random noise as an initiation source of SBS leads to stochastic fluctuations in Stokes intensity and phase. A unified study of both modulations under different parameters is presented. The results indicate a large useful parameter space for excellent Stokes beam quality.Shahraam Afshaarvahid, Vladimyros Devrelis, and Jesper Munc

Comparison of four ways in treatment of acute conversion disorder

چکیده: زمینه و هدف: با وجود شیوع قابل توجه اختلال تبدیلی توافق چندانی در مورد مؤثرترین روش درمان آن وجود ندارد. این مطالعه با هدف مقایسه اثر بخشی چهار روش درمانی اختلال تبدیلی حاد و عود یکماهه آن انجام شد. روش بررسی: در این مطالعه کارآزمایی بالینی 80 بیمار مبتلا به اختلال تبدیلی حاد به روش نمونه گیری آسان انتخاب و به صورت تصادفی تحت درمان با چهار روش تلقین، آرامسازی عضلانی ساده، هیپنوز و تزریق وریدی دیازپام قرار گرفتند. سرعت حذف علامت، فراوانی بهبودی و عود یک ماهه در آنها مقایسه و داده ها به وسیله آزمون های کای دو، فیشر و آنکوا تجزیه و تحلیل گردید. یافته ها: میانگین زمان بهبودی در روش آرامسازی عضلانی نسبت به روش تزریق دیازپام و هیپنوز بطور معنی داری کمتر بود (05/0

Comparison of four ways in treatment of acute conversion disorder

Abstract: (10784 Views) Background and aim: In spite of high prevalence of conversion disorder, there is no widely acceptable effective treatment for it. In this study, we compared four ways of treatment in acute conversion disorder and it’s recurrent after one month. Methods: In a clinical trial study, we selected 80 patients with acute conversion disorder using simple sampling method. They were divided randomly into four treatment groups. (Suggestion, simple muscle relaxation, hypnosis, and diazepam injection) The speed of syndrome elimination, recovery frequency, and one month’s recurrence were compared. The results were analyzed with chi-square, Fisher’s exact test and ANOVA. Results: Mean recovery time was significantly less in muscle relaxation group compared to the hypnosis and diazepam injection groups (P<0.05). In patients with co-morbidity, the mean recovery time was shorter than the mean recovery time in none co-morbidity (P<0.05). There was no significant relation between one month recurrent and way of treatment or other variables. Conclusion: All four ways of treatments bring significant recovery, but in muscle relaxation, recovery is faster than hypnosis and diazepam infusio

Sequential tasks performed by catalytic pumps for colloidal crystallization

Gold-platinum catalytic pumps immersed in a chemical fuel are used to manipulate silica colloids. The manipulation relies on the electric field and the fluid flow generated by the pump. Catalytic pumps perform various tasks, such as the repulsion of colloids, the attraction of colloids, and the guided crystallization of colloids. We demonstrate that catalytic pumps can execute these tasks sequentially over time. Switching from one task to the next is related to the local change of the proton concentration, which modifies the colloid zeta potential and consequently the electric force acting on the colloids

Key Parameters Controlling the Performance of Catalytic Motors

The development of autonomous micro/nanomotors driven by self-generated chemical gradients is a topic of high interest given their potential impact in medicine and environmental remediation. Although impressive functionalities of these devices have been demonstrated, a detailed understanding of the propulsion mechanism is still lacking. In this work, we perform a comprehensive numerical analysis of the key parameters governing the actuation of bimetallic catalytic micropumps. We show that the fluid motion is driven by self-generated electro-osmosis where the electric field originates by a proton current rather than by a lateral charge asymmetry inside the double layer. Hence, the surface potential and the electric field are the key parameters for setting the pumping strength and directionality. The proton flux that generates the electric field stems from the proton gradient induced by the electrochemical reactions taken place at the pump. Surprisingly the electric field and consequently the fluid flow are mainly controlled by the ionic strength and not by the conductivity of the solution, as one could have expected. We have also analyzed the influence of the chemical fuel concentration, electrochemical reaction rates, and size of the metallic structures for an optimized pump performance. Our findings cast light on the complex chemomechanical actuation of catalytic motors and provide important clues for the search, design, and optimization of novel catalytic actuators