Per-packet rate adaptation for wireless video

Streaming video over error-prone wireless channels is a challenge as the dynamic network conditions and slow adaptation to channel degradations may affect the quality of the streamed video. Unequal error protection (UEP) can potentially address this issue by considering the importance of each video packet and its impact on the quality of reconstructed video. This paper proposes a cross-layer UEP solution for wireless video streaming over IEEE 802.11 networks. Video packets are prioritized based on the relative importance of the video packet. UEP is achieved by adapting the link layer parameters on a per-packet basis, using inherent forward error correction and adaptive modulation capabilities of the 802.11n network. Experimental results revealed that the proposed solution achieves comparable performance to the state-of-the-art methods at a lower complexity.     

The protein tyrosine phosphatase SHP-2 is expressed in glial and neuronal progenitor cells, postmitotic neurons and reactive astrocytes

In this study we examined the distribution and developmental profile of the src homology 2 (SH2) domain-containing protein tyrosine phosphatase SHP-2 in the mouse brain. We found that SHP-2 is present in both mitotically active and postmitotic cells in the forebrains of embryonic day 12 (E12) mice. In a developmental study extending from embryonic day 12 to adulthood, Western blotting analysis demonstrated equivalent levels of SHP-2 protein at all of the ages examined. Expression of SHP-2 paralleled the level of enzymatic activity at the different developmental periods. In the adult brain SHP-2 was restricted to diverse classes of neurons, while the majority of glial cells did not express detectable levels of protein. However, reactive astrocytes in response to an ischemic brain injury showed SHP-2 immunolabelling. Our data suggest that SHP-2 may play a role in pathways of neuronal and glial progenitor cells, in a broad spectrum of neuronal responses in the adult brain and in the gliotic response to the injury.     

Probing Site Symmetry Around Eu3+ in Nanocrystalline ThO2 Using Time Resolved Emission Spectroscopy

ThO₂:Eu³⁺ nanoparticles were synthesized at 300°C by combustion route using urea as a fuel and characterized by thermogravimetric/differential thermal analysis, X‐ray diffraction, transmission electron microscopy, and photoluminescence techniques. To investigate the effect of annealing temperature, as synthesized powder were heated further at 500°C, 700°C, and 900°C. It was observed that extent of asymmetry around Eu³⁺ at 700°C/900°C is very high as compared to as‐prepared or 500°C annealed sample. Based on the time resolved emission spectroscopic investigations, it was inferred that two different types of Eu³⁺ ions were present in the ThO₂ nanoparticles. In ThO₂ structure, Eu³⁺ ions occupy two sites; cubic (O_h) and noncubic (<C_2v) as can be confirmed from our emission studies. Short‐lived species T₁ (~1.3–3.4 ms) predominates at higher annealing temperature arises because of Eu³⁺ ions occupying noncubic (<C_2v) sites without inversion symmetry, whereas long‐lived species T₂ (~4.6–6.6 ms) can be ascribed to Eu³⁺ ions occupying cubic sites (O_h) with inversion symmetry.     

Preparation of highly conductive p-type μc-Si:H window layer using lower concentration of hydrogen in the rf glow discharge plasma

Boron doped p-type hydrogenated microcrystalline silicon (μc-Si:H) films have been prepared by radio-frequency glow discharge method. Highly conductive p-type μc-Si:H films can be obtained even with lower concentration of hydrogen in the rf glow discharge plasma if chamber pressure is low. Effects of increase in hydrogen (H₂) flow rate and chamber pressure have been studied. The structural properties of the films have been studied by X-ray diffractometry. The electrical and optical characterization have been done by dark conductivity, Hall measurements and optical absorption measurements respectively. Film with conductivity 0.1(Ω-cm)⁻¹ with band gap 2.1 eV has been obtained.     

Investigation of the MgO∶Fe system using the Mössbauer effect

The MgOFe system as subjected to a variety of heat-treatments has been studied using the Mössbauer effect for Fe⁵⁷. On firing the MgOFe samples in air, iron initially dissolves in the lattice in its ferric state and is associated with a charge-compensating vacancy. However, on exceeding a certain concentration, magnesioferrite precipitates out. Hydrogen firing of these samples tends to create clusters of metallic iron and Fe²⁺ at Mg²⁺ sites. On refiring the samples in air, metallic iron is converted to Fe₂O₃ and Fe²⁺ to Fe³⁺ which subsequently reacts with the lattice to give magnesioferrite and a small fraction of Fe³⁺ dissolved in the lattice. These changes are found to be completely reversible. In some cases the magnesioferrite particle size is so small that it exhibits superparamagnetism. Although there is a limit to the solubility of Fe³⁺ in MgO, Fe²⁺ can be dissolved to any extent.     

Nitrate reductase activity and nitrite levels in the saliva of habitual users of various tobacco products

Nitrite found in human saliva is the product of the microbial reduction of nitrate circulating through the salivary glands. Saliva samples were collected under controlled conditions from volunteers who were habitual users of different types of tobacco products (tobacco chewers, cigarette smokers, bidi smokers and masheri users) and from controls. The saliva samples were analysed for nitrite levels and for nitrate reductase activity spectrophotometrically. Samples were collected from two different areas, Bombay (urban) and Ghodegaon (rural). Salivary nitrite levels in the control groups ranged from 1.6 ppm in Ghodegaon to 11 ppm in Bombay. The nitrite levels of the masheri-using groups from both locations and of the tobacco-chewing group from Bombay were significantly higher than those of the controls. A number of volunteers showed undetectable levels of salivary nitrate reductase. Volunteers who chewed tobacco or used masheri had higher levels of nitrate reductase activity than the controls. However, there did not seem to be any clear correlation between nitrite levels and nitrate reductase activity in the saliva.     

Choice of selective coating for flat plate collectors

A simplified method is presented for the comparison of thermal performance of two similarly fabricated flat plate collectors having absorbers coated with coatings of known solar absorptance and emittance with close values. It essentially determines the insolation value at which the two collectors have the same thermal performance. Curves have been presented which can be directly utilized by the designer for selecting the coating having better thermal performance.     

Labeling of MR brain images using Boolean neural network

Presents a knowledge-based approach for labeling two-dimensional (2-D) magnetic resonance (MR) brain images using the Boolean neural network (BNN), which has binary inputs and outputs, integer weights, fast learning and classification, and guaranteed convergence. The approach consists of two components: a BNN clustering algorithm and a constraint satisfying Boolean neural network (CSBNN) labeling procedure. The BNN clustering algorithm is developed to initially segment an image into a number of regions. Then the segmented regions are labeled with the CSBNN, which is a modified version of BNN. The CSBNN uses a knowledge base that contains information on image-feature space and tissue models as constraints. The method is tested using sets of MR brain images. The regions of the different brain tissues are satisfactorily segmented and labeled. A comparison with the Hopfield neural network and the traditional simulated annealing method for image labeling is provided. The comparison results show that the CSBNN approach offers a fast, feasible, and reliable alternative to the existing techniques for medical image labeling.