922 research outputs found
High-Rate Space-Time Coded Large MIMO Systems: Low-Complexity Detection and Channel Estimation
In this paper, we present a low-complexity algorithm for detection in
high-rate, non-orthogonal space-time block coded (STBC) large-MIMO systems that
achieve high spectral efficiencies of the order of tens of bps/Hz. We also
present a training-based iterative detection/channel estimation scheme for such
large STBC MIMO systems. Our simulation results show that excellent bit error
rate and nearness-to-capacity performance are achieved by the proposed
multistage likelihood ascent search (M-LAS) detector in conjunction with the
proposed iterative detection/channel estimation scheme at low complexities. The
fact that we could show such good results for large STBCs like 16x16 and 32x32
STBCs from Cyclic Division Algebras (CDA) operating at spectral efficiencies in
excess of 20 bps/Hz (even after accounting for the overheads meant for pilot
based training for channel estimation and turbo coding) establishes the
effectiveness of the proposed detector and channel estimator. We decode perfect
codes of large dimensions using the proposed detector. With the feasibility of
such a low-complexity detection/channel estimation scheme, large-MIMO systems
with tens of antennas operating at several tens of bps/Hz spectral efficiencies
can become practical, enabling interesting high data rate wireless
applications.Comment: v3: Performance/complexity comparison of the proposed scheme with
other large-MIMO architectures/detectors has been added (Sec. IV-D). The
paper has been accepted for publication in IEEE Journal of Selected Topics in
Signal Processing (JSTSP): Spl. Iss. on Managing Complexity in Multiuser MIMO
Systems. v2: Section V on Channel Estimation is update
Impact of Psycho- Educational Training Program on Practice, Stress and Coping Strategies of Parents Having Children with Attention Deficit Hyperactivity Disorders
Attention deficit hyperactivity disorders (ADHD) is a developmental condition that involves problems with inattention and hyperactivity- impulsivity inconsistent with the age of the child.. The affected child often has difficulty learning, giving rise to special educational needs that, combined with poor peer and family relationship. In fact, having a child with ADHD is correlated with significant increases in the amount of parent stress that is experienced.Parents of children with ADHD also report less helpful social support and having fewer outside resources may increase the family burden of effectively overcoming the child’s disruptive behaviors. Therefore, parents' psycho-education programs must be carried out in groups to help children as well as their parents how to deal with their difficulties. Therefore, this study aimed to assess the effect of psycho-educational training program on practice, stress and coping strategies of parents having children with ADHD.Quasi-experimental design was selected for this study. Subjects were consists of (80) parents and their children with ADHD attended the out- patient clinic for child with ADHD at El Abassia mental healthhospital.The results denoted that there was a significant improvement in parent knowledge & practice as wellas were significant decrease in the stress levelafter pogrom implementation andthere was a siginificant differenceregarding coping strategies before and after programimplementation.So the study recommended that more education for health care professionals in particular is needed to enable appropriate guidance for parents about the best available treatment for this disorder so that outcomes for children with ADHD may be enhanced. Keywords: Attention Deficit Hyperactivity Disorders, Psychological Intervention, Training Program, Parents, Children, Coping Strategie
Enhancing the Performance of Power System under Abnormal Conditions Using Three Different FACTS Devices
In this paper, a comparison between Flexible Alternating Current Transmission System (FACTS) devices including Static Synchronous Compensator (STATCOM), Static Synchronous Series Compensator (SSSC) and Unified Power Flow Controller (UPFC) for providing a better adaptation to changing operating conditions and improving the usage of current systems. The power system using FACTS devices is presented under different conditions such as single phase fault and three phase fault. A digital simulation using Matlab/Simulink software package is carried out to demonstrate the better performance including the voltage and the current of the presented system using FACTS that located between buses B1 and B2 under different faults types. The results obtained investigate that the presented system gives better response with FACTS as compared to not using them under abnormal conditions besides, the UPFC gives better performance of power system under several faults as compared to STATCOM or SSSC as It can absorb reactive power in a manner which significantly reduced the fault current. It is demonstrated that UPFC can reduce the peak fault current at bus B1 to 63.85% of its value without using FACTS devices under line to ground fault and 79.18% under three line to ground fault whereas STATCOM and SSSC reduce it to (75.21, 94.35%) and (75.40, 94.68%), respectively
Preparation and Histological Study of Multi-Walled Carbon Nanotubes Bone Graft in Management of Class II Furcation Defects in Dogs
BACKGROUND: The main target of periodontal disease and alveolar bone defeat treatment is the regeneration of the lost structures.
AIM: This work deals with the evaluation of the effect of functionalised multi-walled carbon nanotubes (MWCNTs), as grafting material in the management of furcation defects created in dogs.
MATERIAL AND METHODS: Potential cytotoxicity of the grafting material was assessed. Scanning electron microscope (SEM) and energy dispersive x-ray (EDX) analysis after incubation of the grafting material in simulated body fluid (SBF) at pH 7.4 and 37°C for one week was done. In six healthy mongrel dogs' full-thickness mucoperiosteal flaps were raised on the buccal aspects to create two walls intrabony defects at the furcation areas. The mandibular premolar area received the grafting material. Histological evaluation was carried out at 1, 2- and 3-months’ period.
RESULTS: Cytotoxicity results proved the safety of grafting material application. The prepared material exhibited good Ca-apatite crystal patterns at the surface revealed by SEM and high calcium content showed by EDX results. Good bone formation ability was also apparent histologically.
CONCLUSION: The prepared grafting material (MWCNTs) can serve as a delivery vehicle for osteogenic cells and osteogenic growth factor proteins in the bone development process
Effect of subchronic intake of green tea extract on liver of albino rat histomorphometric, ultrastructural and biochemical study
Background: There are conflicting reports on the effect of green tea extract (GTE) on the liver of animals. Some studies failed to show any adverse hepatic effects following administration of GTE to mice, rats, and dogs. Others reported severe hepatic necrosis, resulting in death in female Swiss-Webster mice following its administration. The aim of the study was to examine the subchronic toxicity of GTE on the liver of the adult male albino rats.
Materials and methods: Forty male adult Wistar albino rats were used in the study. The rats were divided into four groups; group I (control), group II (low-dose green tea), group III (medium-dose green tea) and group IV (high-dose green tea). Histological, biochemical and histomorphometric analyses were done.
Results: Mild hepatic affections were observed in group II. The affections were severe in groups III and IV. The central veins and hepatic sinusoids were congested. The hepatocytes were degenerated. Hypertrophy of the hepatic arteries, dilation of the bile ducts and cellular infiltration were clearly observed in the last two groups. Mild degenerative changes were observed in the hepatocytes in rat’s group II; the cytoplasm was rarefied and vacuolated. Some mitochondria were ruptured. The blood sinusoids were congested. The rough endoplasmic retinaculum was fragmented in group III. More degenerative changes were observed in group IV; the hepatic architectures were lost with disruption of cell membranes. Most of the cell organelles were degenerated and most of mitochondria were ballooned. As compared to that of the control groups: the total serum protein values in groups II, III and IV showed a statistically significant decrease (12%, 20% and 21%, respectively), the mean area per cent of collagen fibres in groups III and IV increased 5 and 7 folds.
Conclusions: Subchronic administration of GTE resulted in structural and functional affection of the rats’ liver. The dose of 250 mg/kg/day seemed to be safe, while the doses of 500 mg/kg/day and 1000 mg/kg/day had deleterious effect being more evident in the latter dose
Učinak zamjene obroka od pšeničnih mekinja obrokom sa sjemenkama kima na nesenje, kvalitetu jaja i masnokiselinski profil u kokoši nesilica
The objective of the present study was to investigate the effect of substituting wheat bran (WB) with cumin seed meal (CSM) on laying performance, egg quality characteristics and egg-yolk fatty acids profile in laying hens. A total of 180 Bovans hens at 55 weeks of age were divided randomly into three treatments. The CSM was incorporated into a standard corn- and soybean meal-based diet by replacing 0, 50, and 100% of WB [i.e., 100% WB (control), 50% WB+50% CSM and 100% CSM] from 55 to 61 weeks of age. Body weight was measured at the beginning and end of the experiment. Feed intake, hen-day egg production and egg weight were recorded daily. At 61 weeks of age, 30 eggs were taken at random from each treatment group to determine the egg quality characteristics. Replacing 100% of WB by CSM did not affect body weight, however, hen-day egg production, egg weight and egg mass significantly increased, while feed conversion ratio significantly decreased (P<0.05). Haugh unit, shell thickness and yolk color significantly increased by CSM substitution in comparison with 100% WB. Plasma concentrations of total cholesterol, triglycerides, LDL-cholesterol and glutamic oxalacetic transaminase (GOT) significantly decreased by replacing WB with CSM, while, plasma HDL-cholesterol significantly increased. Furthermore, the liver malondialdehyde (MDA) concentration significantly decreased, while vitamin E, linoleic acid and alpha-linolenic acid significantly increased (P<0.05) due to CSM inclusion. Therefore, it could be concluded that substitution of WB with CSM could improve laying performance and egg quality characteristics, and reduce lipid peroxidation in laying hens.Cilj ovoga rada bio je istražiti učinak zamjene obroka s pšeničnim mekinjama (WB) obrokom sa sjemenkama kima (CSM) na nesenje, kvalitetu jaja te profil masnih kiselina u žumanjku jajeta kokoši nesilica. Ukupno je 180 Bovans kokoši u dobi od 55 tjedana slučajnim odabirom podijeljeno u tri pokusne skupine, u kojima su sjemenke kima dodane u standardni obrok s kukuruzom i sojom zamjenjujući 0, 50 i 100 % pšeničnih mekinja. Tako je kontrolna skupina hranjena obrocima sa 100 % pšeničnih mekinja, druga skupina s 50 % obroka s pšeničnim mekinjama i 50 % obroka sa sjemenkama kima, a treća skupina obrokom koji je sadržavao 100 % sjemenki kima. Pokusno razdoblje je trajalo od 55. do 61. tjedna starosti nesilica. Tjelesna je masa mjerena na početku i na kraju pokusa. Unos hrane, dnevna proizvodnja jaja i njihova masa bilježili su se svaki dan. U dobi od 61 tjedna iz svake je skupine slučajnim odabirom uzeto 30 jaja kako bi se odredila njihova kvaliteta. zamjenjujući 100 % obrok od pšeničnih mekinja sjemenke kima nisu utjecale na tjelesnu masu, no ipak su dnevna proizvodnja, težina i masa jaja znakovito porasle, dok se stopa konverzije hrane znakovito smanjila (P<0,05). Haugh-ova jedinica, debljina ljuske i boja žumanjka znakovito su porasle u skupinama u kojima su pšenične mekinje zamijenjene sjemenkama kima u odnosu na kontrolnu skupinu. Ukupni kolesterol, trigliceridi, LDL-kolesterol i glutaminska oksalooctena transaminaza (GOT) znakovito su sniženi u skupinama u kojima su pšenične mekinje zamijenjene sjemenkama kima, dok je HDL-kolesterol znakovito povišen. nadalje, koncentracija malondialdehida (MDA) u jetri znakovito je snižena, dok su vitamin E, linolna i alfa-linolna kiselina znakovito porasli (P<0,05) uslijed dodanih sjemenki kima. Može se zaključiti da zamjena obroka s pšeničnim mekinjama obrokom sa sjemenkama kima može poboljšati nesenje i kvalitetu jaja te smanjiti lipidnu peroksidaciju u kokoši nesilica
Four-leg active power filter control with SUI-PI controller
Four-leg active power filter is considered one of the greatest vital active filters that are frequently used in industrial applications, especially those that need to be controlled in each individual phase. Also, to control the neutral current that created because of a lot of unbalanced and non-linear loads. In this paper, the used active filter was controlled by a proposed control method which can achieve simplicity and intelligence at the same time. The novelty of this paper is using the proposed controller with Four-leg active power filter. This controller relies on instantaneous reactive power theory, which used to create the required currents that are injected into the network via the used active filter to remove the problems created by unbalanced and non-linear loads. It is also maintained that the current source a pure sinusoidal wave. The system is implemented on MATLAB/Simulink. The simulation results proved the preference of the proposed controller than the conventional proportional-integration controller, where it reduced the percentage of total harmonic distortion for the current source
The role of hepatic progenitor cells in predicting response to therapy in Egyptian patients with chronic hepatitis C, genotype 4
Background: Interferon therapy is used as a line of treatment of chronic hepatitis C virus (HCV) in several areas of the world including Egypt.Objective: Our aim was to investigate the value of hepatic progenitor cells (HPCs) in predicting response of patients with chronic HCV, genotype 4 to pegylated interferon (PEGIFN) plus ribavirin (RBV) therapy.Methods: Pre-treatment liver biopsies obtained from 110 patients with chronic HCV, genotype 4 were examined immunohisto- chemically for HPCs using cytokeratin19. The mean number of HPCs as ductular reaction (DR) and as isolated progenitor cells (IPCs) was counted in each case. The patients were classified into: those with sustained virological response (SVR) and those who did not achieve SVR. The results were compared between the two groups. Also, the relationships between HPCs and other clinico-pathologic variables were estimated using multivariate analysis.Results: The mean number of HPCs was the only independent predictor of therapeutic response, being significantly higher in non-responders (P = 0 for DR and P = 0.03 for IPCs). On the other hand, fibrosis stage and steatosis were the only independent factors which showed a significant direct association with the mean number of HPCs in the form of DR and IPCs (P = 0 for each).Conclusion: The number of HPCs provides prognostic information in chronic HCV since it is significantly associated with stage of fibrosis. More importantly, it can be used as a marker to predict response of patients with chronic HCV to PEGIFN plus RBV therapy.Keywords: Chronic hepatitis C, genotype 4, response to therapy, hepatic progenitor cells
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