157 research outputs found

    Dual Band Meander Line Antenna for Wireless LAN Communication

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    International audienceA printed meander line antenna is described with a shaped ground plane and a back coupled rectangular patch. The prototype is proposed for wireless local-area network (WLAN) applications in the 2.4-2.48GHz and 5.15-5.35 GHz frequency range. Dual-band operation, resonance impedance matching, and wide impedance bandwidth are the characteristics of the antenna. The antenna impedance matching for the first-resonance is provided by applying a shaped ground plane. The second even-mode resonance is generated by adding a rectangular patch at the back of the meander antenna. The impedance bandwidth for a return-loss less than -10 dB is 11% and 6% for the first- and the second-resonance, respectively. Furthermore, the second-resonance frequency can be tuned by the length of the rectangular patch and it meets the requirements for the IEEE 802.11a WLAN (5.15-5.35 GHz and 5.470-5.725 GHz or 5.725-5.825GHz). In fact, the second-resonance frequency can be continuously adjusted between 5.2 and 7 GHz with a little effect on the first-resonance

    Performance Enhancement of Multiuser Time Reversal UWB Communication System

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    UWB communication is a recent research area for indoor propagation channels. Time Reversal (TR) communication in UWB has shown promising results for improving the system performance. In multiuser environment, the system performance is significantly degraded due to the interference among different users. TR reduces the interference caused by multiusers due to its spatial focusing property. The performance of a multiuser TR communication system is further improved if the TR filter is modified. In this paper, multiuser TR in UWB communication is investigated using simple TR filter and a modified TR filter with circular shift operation. The concept of circular shift in TR is analytically studied. Thereafter, the channel impulse responses (CIR) of a typical indoor laboratory environment are measured. The measured CIRs are used to analyze the received signal peak power and signal to interference ratio (SIR) with and without performing the circular shift operation in a multiuser environment

    Uso de la gamificación para mejorar la calidad educativa de los niños con autismo

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    This study was conducted with a pre-test–post-test design with a control group in which participants were divided into two experimental (ten persons) and control (ten persons) groups. The Smile 1 intervention took place in 16 sessions of 30 min, which consisted of eight sessions of 1 h owing to the time spent by the parents of the participants in the study. Additionally, a Child Behaviour Check List (CBCL) was used to measure the effectiveness of this interventional game on reducing the behavioural problems of children that participated. The questionnaire consists of 113 questions in which 13 different behavioural factors are identified in the children. For this purpose, pre-test and post-test stages were performed for both groups. In fact, due to time constraints for holding intervention sessions, it was expected from the outset that significant changes in participant behaviour during the two months of interventions would not be observed.Este estudio se realizó con un diseño pre-test-post test con un grupo de control en el que los participantes se dividieron en dos grupos experimentales (diez personas) y de control (diez personas). La intervención de Smile 1 se llevó a cabo en 16 sesiones de 30 minutos, que consistieron en ocho sesiones de 1 hora debido al tiempo que pasaron los padres de los participantes en el estudio. Además, se utilizó una Lista de control de la conducta infantil (CBCL) para medir la eficacia de este juego intervencionista en la reducción de los problemas de conducta de los niños que participaron. El cuestionario consta de 113 preguntas en las que se identifican 13 factores conductuales diferentes en los niños. Para ello, se realizaron etapas de pre-test y post-test para ambos grupos. De hecho, debido a las limitaciones de tiempo para realizar las sesiones de intervención, se esperaba desde el principio que no se observaran cambios significativos en el comportamiento de los participantes durante los dos meses de las intervenciones

    Transient fault area location and fault classification for distribution systems based on wavelet transform and Adaptive Neuro-Fuzzy Inference System (ANFIS)

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    A novel method to locate the zone of transient faults and to classify the fault type in Power Distribution Systems using wavelet transforms and Adaptive Neuro-Fuzzy Inference Systems (ANFIS) has been developed. It draws on advanced techniques of signal processing based on wavelet transforms, using data sampled from the main feeder current to extract important characteristics and dynamic features of the fault signal. In this method, algorithms designed for fault detection and classification based on features extracted from wavelet transforms were implemented. One of four different algorithms based on ANFIS, according to the type of fault, was then used to locate the fault zone. Studies and simulations in an EMTP-RV environment for the 25kV power distribution system of Canada were carried out by considering ten types of faults with different fault inception, fault resistance and fault locations. The simulation results showed high accuracy in classifying the type of fault and determining the fault area, so that the maximum observed error was less than 2%

    GROUND REACTION FORCES ATTENUATION IN SUPINATED AND PRONATED FOOT DURING SINGLE LEG DROP- LANDING

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    The purpose of this study was to compare the GRF attenuation between normal, supinated and pronated foot during single leg drop-landing. 30 healthy male students from kinesiology department participated in this study. Subjects were assigned to three groups by navicular drop test and performed single leg drop-landing on the force plate from the box with height of 30 Cm. peak VGRF and ROL calculated using GRF data. To evaluate differences in peak VGRF and ROL between three groups MANOVA at the P level of 0.05 used. Differences in ROL was significant between three groups (F2, 22=15.553, Wilks’ Lambda = 0.370, ) but differences in Peak VGRF was not significant (F2, 22 = 2.632,). These results suggest that supinated foot is associated with specific lower extremity kinetics. Differences in these parameters may subsequently lead to differences in injury patterns in supinated foot in athletes

    The effects of the Lactobacillus acidophilus ATCC 4356 on the oxidative stress of reproductive system in diabetic male rats

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    Background: Oxidative stress plays an important role in the development of diabetic complications. Objective: This study evaluated the impact of pre- and post-treatment with Lactobacillus acidophilus ATCC 4356 on the oxidant and anti-oxidant factors of testis and epididymis in streptozotocin-induced diabetic rats. Materials and Methods: Thirty male Wistar rats (10 wk old) weighing 220-230 g. were divided into five groups (n = 6/ each): 1- normal group, 2- normal lactobacillus group, 3- diabetic group, 4- diabetic + lactobacillus before (DLB) group, and 5- diabetic + lactobacillus after (DLA) group. The normal and diabetic groups received daily 1 mL normal saline for 6 wk. Normal lactobacillus group received daily L. acidophilus for 6 wk. Group DLB received daily L. acidophilus for 2 wk before diabetes and for 4 wk after diabetes. Group DLA received daily 1 mL normal saline for 2 wk before diabetes and L. acidophilus for 4 wk after diabetes. The dose of L. acidophilus was 1 × 109 CFU/mL. Results: The administration of L. acidophilus worsened blood glucose level and reduced the levels of Malondialdehyde (p = ≤ 0.0001) and Hydrogen peroxide (p ≤ 0.0001) and, Catalase and Glutathione peroxidase activity increased in the testis. In epididymis, Glutathione peroxidase and Catalase (p = 0.013) activity increased and Hydrogen peroxide concentration reduced, while Malondialdehyde concentration did not show any changes compared to the diabetic rats. Also, there was no significant difference between DLB and DLA groups, in these markers. Conclusion: Data obtained suggests that L. acidophilus has anti-oxidant effects on the testis and sometime in the epididymis in diabetic rats

    Multiuser Time Reversal UWB Communication System: A Modified Transmission Approach

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    International audienceIn this paper, ultra-wideband (UWB), time reversal (TR) communication is investigated by modifying the transmission prefilter. Mathematical expressions for received signal and the interference in the modified transmission scheme are derived. It is shown that the modified transmission approach reduces multi-user interference which eventually translates into a better bit error rate (BER) performance than simple TR multiuser scheme. Channel impulse responses (CIR) of a typical indoor channel are measured. In a multi-user scenario, both TR and the modified TR schemes are studied using the measured CIRs. It is shown that the proposed modified TR scheme outperforms the original TR scheme

    Permanent Fault Location in Distribution System Using Phasor Measurement Units (PMU) in Phase Domain

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    This paper proposes a new method for locating high impedance fault in distribution systems using phasor measurement units (PMUs) installed at certain locations of the system. To implement this algorithm, at first a new method is suggested for the placement of PMUs. Taking information from the units, voltage and current of the entire distribution system are calculated. Then, the two buses in which the fault has been occurred is determined, and location and type of the fault are identified. The main characteristics of the proposed method are: the use of distributed parameter line model in phase domain, considering the presence of literals, and high precision in calculating the high impedance fault location. The results obtained from simulations in EMTP-RV and MATLAB software indicate high accuracy and independence of the proposed method from the fault type, fault location and fault resistance compared to previous methods, so that the maximum observed error was less than 0.15

    Lavender and the Nervous System

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    Lavender is traditionally alleged to have a variety of therapeutic and curative properties, ranging from inducing relaxation to treating parasitic infections, burns, insect bites, and spasm. There is growing evidence suggesting that lavender oil may be an effective medicament in treatment of several neurological disorders. Several animal and human investigations suggest anxiolytic, mood stabilizer, sedative, analgesic, and anticonvulsive and neuroprotective properties for lavender. These studies raised the possibility of revival of lavender therapeutic efficacy in neurological disorders. In this paper, a survey on current experimental and clinical state of knowledge about the effect of lavender on the nervous system is given

    Prevalence of Psychiatric Disorders among Children and Adolescents: A Study from Khuzestan

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      Objective This cross-sectional study aimed to study the prevalence rate of psychiatric disorders in children and adolescents in Khuzestan province. Materials & Methods A community sample consisting of 1028 (51.6% female) children and adolescents aged 6-18 years was selected using a multistage cluster sampling method. Data were gathered using the Kiddie-SADSPresent and Lifetime Version (K-SADS-PL) and a demographic questionnaire (i.e., gender, age, level of education, place of residence, parent’s education, and parent’s Job) Results Nearly 22.6% (22.3% of boys and 23% of girls) of all participants suffered from at least one psychiatric disorder. There was no significant difference in the prevalence of psychiatric disorders based on gender, age, father’s education, mother’s education, mother’s job, and father’s job (all p>0.05). Psychiatric disorders were significantlymore prevalent among children and adolescents in urban areas compared to rural places (2.9% vs. 8.1; p<0.001). The most prevalent category was anxiety disorders (15%). Also, the most common disorders were specific phobia (7%), separation anxiety disorder (6.3%), and enuresis (5.2%). The most common comorbid disorders were mood disorders and anxiety disorders (56.3%), followed by anxiety disorders and elimination disorders (32.1%). ConclusionPsychiatric conditions are prevalent in children and adolescents living in Khuzestanian. The study’s findings have important implications for providing effective psychiatric services.   &nbsp
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