M. Sharif - Academia.edu (original) (raw)

Papers by M. Sharif

The Thrity-Seventh Asilomar Conference on Signals, Systems & Computers, 2003, 2000

Abslract-In this paper we show that "separation"-based approaches in wireless networks do not nec... more Abslract-In this paper we show that "separation"-based approaches in wireless networks do not necessarily give good performance in terms of the capacity of the network. Therefore In optimal design of a wireless network, Its total structure should be considered. In other words, achieving capacity on the subnetworks of a wireless network does not guarantee globally achieving capacity. We will illustrate this fact by considering some examples of multistage Gaussian wireless rciay networks. We wlll consider a wireless Gaussian relay network with one stage in both fading and non-fadlng environment. We show that as the number of relay nodes, n, grows large, the capacity of this network scales like iogn. We then show that with the "separation"4ased scheme, in which the network is viewed as the concatenation of a broadcast and a multi-access network, the achievable rate scales as log log n and as a constant for fading and uon-fadine environment, respectively, which is clearly sub-optimal.

Tropical animal health and production, 2009

Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that ... more Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that can excrete environmentally resistant oocysts. T.gondii is a major zoonotic agent which infects up to one-third of the world population. Toxoplasmosis in neonates and immunocompromised patients can lead to severe disease and death. A cross- sectional parasitological and serological survey with latex agglutination test (LAT) to detect anti-T. gondii antibodies was conducted on 100 serum samples collected from stray cats in five urban areas of Sari, Northern Iran, from April to November 2004. Classification by age, sex, weight, season and region was made. Results analyzed according to specific variables. The overall prevalence of T. gondii IgG antibodies (LAT titre > or = 1:1) were found in 40 of 100(40%) of stray cats, with regional variations. Overall 16 of 100(16%) of stray cats had diagnostically significant antibody titres (LAT > or = 1:64). Prevalence was significantly higher i...

Journal of Parasitic Diseases, 2013

Over the last decade, a few cases of visceral leishmaniasis (VL) have been reported in some distr... more Over the last decade, a few cases of visceral leishmaniasis (VL) have been reported in some districts of the province of Golestan, in north-eastern Iran. The aim of the present study was to investigate the prevalence of Leishmania infantum infection among humans and domestic dogs by using direct agglutination test (DAT) and PCR assays in the eastern zone of the province. Between 2011 and 2012, blood samples were randomly collected from 450 humans and 50 domestic dogs, in the eastern zone of Golestan Province including 7 villages from Marave-tappeh district where new cases of human VL had been recorded there. Each of these samples was tested for anti-Leishmania antibodies, in DAT, and for L. infantum kinetoplast DNA on whole blood, in PCR-based assays. A total of 450 human samples, 6 (1.33 %) were found seropositive and 13 (2.8 %) was found PCR-positive. Of the 50 dog samples, 16 (32 %) were found seropositive and 15 (30 %) were PCR-positive. All PCR-positive dogs were found seropositive except one as well as 6 (46.2 %) PCR-positive humans were also found seropositive. Moreover, the species of L. infantum was detected in all PCR-positive samples. The high prevalence of VL in the study areas offer it has emerged as an endemic focus in the province. Further investigations on the vectors, reservoirs and human population are recommended.

Veterinary Record, 2000

The efficacy of calcium pentosan polysulphate (CaPPS) as a slow-acting drug for the treatment of ... more The efficacy of calcium pentosan polysulphate (CaPPS) as a slow-acting drug for the treatment of osteoarthritis of the canine stifle joint, secondary to cranial cruciate ligament deficiency, was tested in a double-blind, placebo-controlled clinical trial over a period of one year. Dogs with the deficiency were treated surgically, matched for bodyweight, and randomly assigned to treatment or placebo groups. Active treatment began six weeks postoperatively and consisted of 10 mg/kg caPPs orally, once weekly for four weeks, repeated every 12 weeks. The outcome was assessed in terms of function by the dogs' owners, by the radiographical grading of the osteoarthritis, and by the measurement of total sulphated glycosaminoglycans and the 5D4 epitope of keratan sulphate in the synovial fluids of affected joints. There were no differences either in functional outcome or in the radiographical progression of osteoarthritis between the two groups. Fifty-four weeks after surgery, the concentration of 5D4 in synovial fluid (expressed as change from baseline values) had decreased significantly in the treatment group compared with the placebo group (P=0-03).

Skeletal Radiology, 2004

tive scintigraphy. Conclusion: DXA may provide a safe, rapid and reliable means of assessing knee... more tive scintigraphy. Conclusion: DXA may provide a safe, rapid and reliable means of assessing knee OA. Crosssectional age-related subchondral tibial BMD loss is attenuated by knee OA.

Rheumatology International, 2011

To investigate whether there are any variations in chondrocyte susceptibility to an apoptotic sti... more To investigate whether there are any variations in chondrocyte susceptibility to an apoptotic stimulus between cells of articular cartilage (AC) from equine joints that differ in prevalence of osteoarthritis (OA). Cartilage from macroscopically normal equine metacarpophalangeal (MCP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints was used. Prior to culture, chondrocyte viability was assessed using the fluorescein diacetate (FDA) and propidium iodide paravital staining method. AC explants were subsequently treated with tumour necrosis factor-α (TNF-α) in combination with Actinomycin D to induce apoptosis. Apoptosis of chondrocytes in cartilage sections was assessed by expression of active caspase-3 using indirect immunohistochemistry and sections also histologically graded using a 'modified' Mankin scoring system. Prior to culture (mean ± standard deviation) chondrocyte viability was 80.7% (3.5). The extent of chondrocyte apoptosis induced by TNF-α/Actinomycin D varied markedly according to the joint type that the cartilage was sampled from. For MCP joints, the extent of overall chondrocyte apoptosis was significantly higher (P < 0.001) in stimulated explants (26.7%, 10.3) than that observed in unstimulated control samples (9.6%, 7.5). Conversely, chondrocytes from PIP and DIP joint cartilage did not respond significantly to apoptotic stimulation (P > 0.05). Significant variations in cellularity and thickness were also evident between cartilages of different joint types. Data in this study demonstrate that chondrocytes from three equine joint types with varying prevalences of OA differ significantly in terms of susceptibility to apoptosis induction. This may provide a possible explanation for the joint-specific nature of the disease.

Research in Developmental Disabilities, 2007

Serological studies revealed that toxoplasmosis has world wide distribution. Although the infecti... more Serological studies revealed that toxoplasmosis has world wide distribution. Although the infection by Toxoplasma gondii is widely prevalent in humans and animals, the disease is uncommon and most of the acquired infections are asymptomatic. The important aspect of this parasitic infection is the probable danger of congenital transmission and its severe effects on the fetus. There have been many reports about the prevalence of anti-T. gondii antibody among different groups of people in Iran; however the epidemiological data in intellectual disability (ID) persons are rare. This study was performed to evaluate the seroprevalence of toxoplasmosis among the inhabitants of rehabilitation centers of northern Iran. A total of 336 serum samples (161 males, 175 females) were examined for the IgG antibodies by indirect immunofluorescense technique. First of all, 1:50 titer dilution was tested, in the cases of positive result, further dilutions (1:100, 1:200, 1:400, 1:800, 1:1600, and 1:3200) were prepared and the last dilution was recorded. Among 336 sera, 77.4% showed seropositivity by IFAT. The positive rates of males and females were 77.6% (125/161) and 80% (140/175), respectively. However, there were no significant differences between sexes. Comparing the age groups, the highest seropositive rate showed in 19 or higher, and their rates had a tendency to increase with age. Prevalence of the infection in 10 rehabilitation centers was not significant either. Nevertheless, our data (77.4%) in rehabilitation centers in northern Iran suggest that infection is the same as in many other reports in normal population in this area, therefore toxoplasmosis is not a major problem in rehabilitation centers of this geographical area. #

Proceedings of the ICE - Water Management, 2005

This paper describes the potential use of a genetic algorithm for real-time regulation of Lake Vi... more This paper describes the potential use of a genetic algorithm for real-time regulation of Lake Victoria at Owen Falls dam. The objective was to develop a procedure that would permit short-to medium-term forecasts of potential reliable power generation that would improve utilisation of high lake levels. An operational control procedure has been developed, based on a genetic algorithm, that permits forecasts to be made of potential reliable power output at Owen Falls and any future hydropower stations on the Victoria Nile, at lead times of 3, 6, 12 and 24 months. Such forecasts could be of value in planning outage of thermal power plants and in maximising power benefits associated with high lake levels. With regulation, the reliable power output from Lake Victoria and the Victoria Nile can be significantly improved. Impacts downstream of Lake Kyoga would not be significant.

Plasma Sources Science and Technology, 2002

The x-ray emission from a low-energy (2.3 kJ) plasma focus is investigated with neon as the filli... more The x-ray emission from a low-energy (2.3 kJ) plasma focus is investigated with neon as the filling gas. Two anode configurations are used in the experiment: the conventional cylindrical anode, and tapered anode slightly toward the open end. The latter geometry enhances soft x-ray emission by an order of magnitude. The emission is pressure dependent and, in both cases, the highest emission is observed at 3-3.5 mbar. For the cylindrical anode, the soft x-ray emission is up to 7 J per shot, which is from a pinched plasma column, 5-6 mm long. For the tapered anode, up to 80 J per shot soft x-ray yield in 4π geometry is recorded, which corresponds to 4% wall plug efficiency. The diameter of the x-ray emission filament is much larger compared with the cylindrical anode. The bulk of emitted radiation is of energy 1.2-1.3 keV, which is thought to arise from recombination of hydrogen-like (Ne X) ions with the low-energy electrons.

Molecular and Cellular Endocrinology, 1994

Modern Physics Letters A, 2009

In this paper, the effect of electromagnetic field has been investigated on the spherically symme... more In this paper, the effect of electromagnetic field has been investigated on the spherically symmetric gravitational collapse with the perfect fluid in the presence of positive cosmological constant. Junction conditions between the static exterior and non-static interior spherically symmetric spacetimes are discussed. We study the apparent horizons and their physical significance. It is found that electromagnetic field reduces the bound of cosmological constant by reducing the pressure and hence collapsing process is faster as compared to the perfect fluid case. This work gives the generalization of the perfect fluid case to the charged perfect fluid. Results for the perfect fluid case are recovered.

Modern Physics Letters A, 2008

In this short paper we establish the definition of the Lie derivative of a second rank tensor in ... more In this short paper we establish the definition of the Lie derivative of a second rank tensor in the context of teleparallel theory of gravity and also extend it for a general tensor of rank p + q. This definition is then used to find Killing vectors of the Einstein universe. It turns out that Killing vectors of the Einstein universe in the teleparallel theory are the same as in General Relativity.

The Knee, 2005

The clinical effect of intra-articular viscosupplementation has been assessed in patients sufferi... more The clinical effect of intra-articular viscosupplementation has been assessed in patients suffering tibiofemoral osteoarthritis and review of the data suggest pain relief extending to 12 months in such patients. There are no prospective trials of viscosupplementation targeting patients with patellofemoral osteoarthritis (POAK) of the knee, which is frequent, associated with anterior knee pain and often disabling. This pilot study addressed the therapeutic and adverse effects of intra-articular (IA) hylan in patients with evidence of lone POAK. Forty-three outpatients were recruited to receive a (three-injection) course of IA hylan G-F 20 (Synvisc). Patient and clinician global rating and pain on stair climbing improved significantly from 4 weeks post initial injection to 26 weeks. Secondary outcome measures (including the Oxford Knee Outcome Score) were also recorded. Adverse knee events occurred in 18.6% of patients within 48 h, but only two failed to complete the course of injections because of adverse knee events. One hundred and four patients would be required for a randomised controlled trial of IA hylan to effectively demonstrate an effect size of 0.5 (a 15-mm difference between placebo and treatment arm over a 100-mm visual analogue pain scale) with 95% confidence and 90% power, to detect a 15-mm change in VAS (effect size 0.5) with 95% confidence and 90% power. This would require a RCT of 104 patients to detect a 15-mm change in VAS (effect size 0.5) with 95% confidence and 90% power. D

General Relativity and Gravitation, 2007

This paper is devoted to investigate the teleparallel versions of the Friedmann models as well as... more This paper is devoted to investigate the teleparallel versions of the Friedmann models as well as the Lewis-Papapetrou solution. We obtain the tetrad and the torsion fields for both the spacetimes. It is shown that the axial-vector vanishes for the Friedmann models. We discuss the different possibilities of the axial-vector depending on the arbitrary functions ω and ψ in the Lewis-Papapetrou metric. The vector related with spin has also been evaluated.

General Relativity and Gravitation, 2011

We investigate the expanding and collapsing regions by taking two well-known spherically symmetri... more We investigate the expanding and collapsing regions by taking two well-known spherically symmetric spacetimes. For this purpose, the general formalism is developed by using Israel junction conditions for arbitrary spacetimes. This has been used to obtain the surface energy density and the tangential pressure. The minimal pressure provides the gateway to explore the expanding and collapsing regions. We take Minkowski and Kantowski-Sachs spacetimes and use the general formulation to investigate the expanding and collapsing regions of the shell.

Food Control, 2008

Fresh vegetables are an important part of a healthy diet. In recent years there has been an incre... more Fresh vegetables are an important part of a healthy diet. In recent years there has been an increase in the number of reported cases of food-borne illness linked to fresh vegetables. The consumption of raw vegetables is a major way in the transmission of parasitic contaminations. The goal of this study was to determine the parasitological contamination of vegetables sold at markets and obtained from gardens. A total of 141 samples from different vegetables were randomly selected from the markets and gardens (markets: 96; gardens: 45) and then were examined by a concentration method. Each sample was washed with water, allowing sedimentation at room temperature for 24 h. Five ml of sediment were centrifuged at 3000 rpm for 5 min. Sediment was examined in lugol stained slides through light microscopy. Fifty percent (48/96) of markets vegetables and 71% (32/45) of gardens vegetables were contaminated with different parasites. Prevalences of pathogenic parasites in vegetables of markets and gardens were 25% and 29%, respectively. Parasites detected were Giardia cysts (7%), Dicrocoelium eggs (6%), Fasciola eggs (5%) and Ascaris eggs (2%). In regard to results of this study, the importance of vegetables in the transmission of intestinal parasites in stressed, and it is necessary to improve the sanitary conditions of these kinds of food.

The European Physical Journal D, 2006

A 1.8 kJ Mather-type plasma focus (PF) for argon and hydrogen filling is examined. Two anode conf... more A 1.8 kJ Mather-type plasma focus (PF) for argon and hydrogen filling is examined. Two anode configurations are used. One is tapered towards the anode face, and the other is cylindrical but the face is cut at different angles. At optimum conditions, the system is found to emit Cu-Kα X-rays of about 1.6 ± 0.1 J/sr in the side-on direction for argon filling, which is about 32% of the total X-ray emission. In 4π-geometry, maximum total X-ray yield and wall plug efficiency found are 26.4 ± 1.3 J and 1.5 ± 0.1% respectively. The modified geometry may help to use the PF as a radiation source for X-ray diffraction.

Chinese Physics Letters, 2012

ABSTRACT We investigate the dynamical behavior of phantom energy near stringy magnetically charge... more ABSTRACT We investigate the dynamical behavior of phantom energy near stringy magnetically charged black hole. For this purpose, we derive equations of motion for steady-state spherically symmetric flow of phantom energy onto the stringy magnetically charged black hole. It is found that phantom energy accreting onto black hole decreases its mass. Further, the location of critical points of accretion is explored, which yields mass to charge ratio. This ratio implies that accretion process cannot transform a black hole into an extremal black hole or a naked singularity, hence cosmic censorship hypothesis remains valid here.

Chinese Physics Letters, 2011

We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flu... more We deal with phantom energy accretion onto the Schwarzschild de-Sitter black hole. The energy flux conservation, relativistic Bernoulli equation and mass flux conservation equation are formulated to discuss the phantom accretion. We discuss the conditions for critical accretion. It is found that the mass of the black hole decreases due to phantom accretion. There exist two critical points which lie in the exterior of horizons (black hole and cosmological horizons). The results for the phantom energy accretion onto the Schwarzschild black hole can be recovered by taking Lambda --> 0.

Astrophysics and Space Science, 2011

This paper is devoted to study the dynamics of gravitational collapse in the Misner and Sharp for... more This paper is devoted to study the dynamics of gravitational collapse in the Misner and Sharp formalism. We take non-viscous heat conducting charged anisotropic fluid as a collapsing matter with cylindrical symmetry. The dynamical equations are derived and coupled with the transport equation for heat flux obtained from the Müller-Israel-Stewart causal thermodynamic theory. We discuss the role of anisotropy, electric charge and radial heat flux over the dynamics of the collapse with the help of coupled equation.