Modulation and coding used by a major satellite communications company

Hughes Communications Inc., is a major satellite communications company providing or planning to provide the full spectrum of services available on satellites. All of the current services use conventional modulation and coding techniques that were well known a decade or longer ago. However, the future mobile satellite service will use significantly more advanced techniques. JPL, under NASA sponsorship, has pioneered many of the techniques that will be used

Quantifying the Differences in Binding Affinity of Reduced Glutathione for Glutathione S-Transferase at pH 6.5 and 8.5 Using Isothermal Titration Calorimetry

The binding affinity between an enzyme and its substrate is often dependent on the pH of the local environment. Knowing the pH at which reduced glutathione (GSH) binds with the highest affinity to the enzyme glutathione S-transferase (GST) is useful for determining the optimal pH for purification of GST-fusion proteins during GST-affinity chromatography. In this study, GST of the species Schistosoma japonicum was purified, quantified, and utilized to study its binding interaction with GSH at pH 6.5 and 8.5 via isothermal titration calorimetry (ITC). After protein expression, extraction, and purification, the GST concentration was quantified using QubitTM fluorometry. Thermodynamic properties and a dissociation constant (KD) for each experiment were obtained utilizing the MicroCal PEAQ-ITC Analysis Software for the binding of GSH to GST at pH 6.5 and 8.5. Statistical analysis of the technical replicate data was performed to obtain an average and standard deviation of the KD at each pH point. The results indicate a statistically significant difference (

Evaluation of advanced lift concepts and potential fuel conservation for short-haul aircraft

The effect of different field lengths, cruise requirements, noise level, and engine cycle characteristics on minimizing fuel consumption and minimizing operating cost at high fuel prices were evaluated for some advanced short-haul aircraft. The conceptual aircraft were designed for 148 passengers using the upper surface-internally blown jet flap, the augmentor wing, and the mechanical flap lift systems. Advanced conceptual STOL engines were evaluated as well as a near-term turbofan and turboprop engine. Emphasis was given to designs meeting noise levels equivalent to 95-100 EPNdB at 152 m (500 ft) sideline

Comparison of CDMA and FDMA for the MobileStar(sm) system

Spread-spectrum code division multiple access (CDMA) and single channel per carrier frequency division multiple access (FDMA) systems are compared for spectrum efficiency. CDMA is shown to have greater maximum throughput than FDMA for the MobileStar(sm) system which uses digital voice activated carriers and directive circularly polarized satellite antennas

Characterization of hepcidin response to holotransferrin in novel recombinant TfR1 HepG2 cells

Hepcidin is the key regulator of systemic iron homeostasis. The iron-sensing mechanisms and the role of intracellular iron in modulating hepatic hepcidin secretion are unclear. Therefore, we created a novel cell line, recombinant-TfR1 HepG2,expressing iron-response-element-independent TFRC mRNA to promote cellular iron overload and examined the effect of excess holotransferrin (5 g/L) on cell-surface TfR1, iron content, hepcidin secretion and mRNA expressions of TFRC, HAMP, SLC40A1,HFE and TFR2. Results showed that the recombinant cells exceeded levels of cell surface TfR1 in wild-type cells under basal (2.8-fold; p<0.03) and holotransferrin supplemented conditions for 24 h and 48 h (4.4- and 7.5-fold, respectively; p<0.01). Also, these cells showed higher intracellular iron content than wild-type cells under basal (3-fold; p<0.03) and holotransferrin-supplemented conditions (6.6-fold at 4 h; p<0.01). However, hepcidin secretion was not higher than wild-type cells. Moreover, holotransferrin treatment to recombinant cells did not elevate HAMP responses compared to untreated or wild-type cells. In conclusion, increased intracellular iron content in recombinant cells did not increase hepcidin responses compared to wild-type cells, resembling hemochromatosis. Furthermore, TFR2 expression altered within 4 h of treatment, while HFE expression altered later at 24 h and 48 h, suggesting that TFR2 may function prior to HFE in HAMP regulation

Exploring neutrophil behaviour in a zebrafish model of inflammation through the generation of novel parameters using MatLab algorithms

Purpose/Objective: Tracking of immune cells is key to understanding their behaviour during inflammation. Current software available for tracking of immune cells is limited. The aim of this study was to develop a MatLab package of segmentation and tracking algorithms to apply in the tracking of neutrophils, fluorescently labelled in our zebrafish model [1]. The development of algorithms in MatLab allows us to explore parameters not available in other software packages such as directionality of neutrophil movement and neutrophil behaviour in- side and outside of a wound region. Materials and methods: Tail fin transection was performed on Tg(mpx:GFP) zebrafish (3 dpf) which were imaged on a spinning disk confocal from 1 h post injury (hpi) to 7 hpi. Images were exported from VolocityTM and analysed using MatLab m-files written for the tracking of immune cells. This is a fully automated analysis, after the user defines the initial thresholds based on fluorescent intensity of the images. Results: Neutrophils from injured embryos had a lower meandering ratio and a greater speed than neutrophils tracked in uninjured embryos (meandering ratio 0.24 ± 0.03 versus 0.42 ± 0.05, P = 0.003; speed 4.03 ± 0.32 versus 1.31 ± 0.21 pixels/frame, P 0.05). In injured embryos with a defined wound region, the oriented velocity towards the wound was 0.31 ± 0.24 pixels/frame. Once within the wound region, the oriented velocity of neutrophil tracks was -0.39 ± 0.32 pixels/frame; indicating that while the neutrophils travel at a similar speed, they are now travelling away from the wound. The ‘in wound ratio’ was 0.91 ± 0.04, indicating that once neutrophils enter the wound region they tend to stay, in the timeframe studied. The ‘leave wound ratio’ was 0.37 ± 0.03, a measure of the rate at which neutrophils move away from the site of injury once they have entered the wound region. Conclusions: Using these algorithms, we can analyse the behaviour of immune cells in a more detailed way. In addition to previously available parameters such as meandering ratio and speed, more complex parameters such as velocity towards or away from a wound region and a measurement of how neutrophils behave while in a wound region are available. Combining this novel tracking technology with established assays in our laboratory will enable the further dissection of neutrophil fate following an inflammatory stimulus

Tracking neutrophils in zebrafish: the use of synthetic data sets

In this work we present a series of data sets that model the behaviour of neutrophils as observed with a confocal microscope. The data sets describe important characteristics of the migration of neutrophils such as collisions and path tortuosity as well as different levels of background noise. Neutrophil trajectories were manually defined, and Gaussian shapes similar to those of real data sets were assigned to each position of a neutrophil. The availability of synthetic data sets such as the ones proposed here, together with appropriate gold standards will benefit those wanting to test the robustness and accuracy of segmentation and tracking algorithms

Analyzing Powers for Complex Fragments Formed in the 200 MeV pol.p + Ag Reaction

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Proximity-to-goal as a constraint on patterns of behaviour in attacker-defender dyads in team games

Abstract The aim of this study was to determine whether spatiotemporal interactions between footballers and the ball in 1 vs. 1 sub-phases are influenced by their proximity to the goal area. Twelve participants (age 15.3 +/- 0.5 years) performed as attackers and defenders in 1 vs. 1 dyads across three field positions: (a) attacking the goal, (b) in midfield, and (c) advancing away from the goal area. In each position, the dribbler was required to move beyond an immediate defender with the ball towards the opposition goal. Interactions of attacker-defender dyads were filmed with player and ball displacement trajectories digitized using manual tracking software. One-way repeated measures analysis of variance was used to examine differences in mean defender-to-ball distance after this value had stabilized. Maximum attacker-to-ball distance was also compared as a function of proximity-to-goal. Significant differences were observed for defender-to-ball distance between locations (a) and (c) at the moment when the defender-to-ball distance had stabilized (a: 1.69 +/- 0.64 m; c: 1.15 +/- 0.59 m; P < 0.05). Findings indicate that proximity-to-goal influenced the performance of players, particularly when attacking or advancing away from goal areas, providing implications for training design in football. In this study, the task constraints of football revealed subtly different player interactions than observed in previous studies of dyadic systems in basketball and rugby union