The influence of dietary n-3 fatty acids on brain phospholipid composition in Atlantic salmon (Salmo salar)

A feeding experiment was conducted to examine the percentages of different fatty acids in brain phospholipid subclasses under feeding dietary inclusion levels of EPA, DHA or a 1:1 mixture of EPA and DHA in farmed Atlantic salmon. The aim was to investigate how EPA alone, DHA alone or a mix of different doses influence the fatty acids in phospholipid subclasses, and how EPA and DHA deficiency influence the brain phospholipids. Fourteen dietary groups of Atlantic salmon, were fed diets with increasing inclusion levels of EPA, DHA or a 1:1 mixture of EPA and DHA, defined as 0, 0.5, 1, 1.5 or 2% of the feed dry weight, and a commercial diet. The 0 (negative control; NC), 2% and commercial dietary (commercial control; CC) groups were in triplicate, while the dietary groups containing 0.5, 1 and 1.5% were in duplicate tanks. This experiment started at the average fish body weight of 40g, and the brain was taken from 5 fish from each tank in each dietary group when the average fish body weight reached 200g (after 131 d) and 400g (after 186d). These samples were treated by lipid extraction, double TLC and GC to separate the different phospholipid subclasses and determine the fatty acid composition of each subclass. In salmon brain, PC had higher 16:0 and 18:1n-9 and the lowest percentage of Ʃ n-3 fatty acids, PI was characterized by higher 18:0 and 20:4n-6, and PS and PE contained the highest percentages of 22:6n-3. Through PCA, only NC group is separated from the rest of the dietary groups, while there were no clear groupings of the other dietary groups. Furthermore, four phospholipid classes showed increased 20:5n-3 and 22:6n-3 incorporation and concomitantly decreased levels of Ʃ n-6 and Ʃ n-9 fatty acids, with increasing dietary levels of EPA, DHA or a mix of EPA and DHA. For the most of fatty acids, there was only a significant difference in the NC group. When the fish was fed a diet without EPA and DHA, the brain remained containing quite high amounts of EPA and DHA, and DHA was more retained than EPA. In conclusion, phospholipids were characterized by a high degree of percentages of n-3 PUFA (20:5 and 22:6) and low percentages of n-6 PUFA, however, each phospholipid subclass had different characteristic fatty acids. The brain phospholipid fatty acid composition was conserved to a high degree and little affected by the diet.M-A

Likelihood estimation for distributed parameter models for NASA Mini-MAST truss

A maximum likelihood estimation for distributed parameter models of large flexible structures was formulated. Distributed parameter models involve far fewer unknown parameters than independent modal characteristics or finite element models. The closed form solutions for the partial differential equations with corresponding boundary conditions were derived. The closed-form expressions of sensitivity functions led to highly efficient algorithms for analyzing ground or on-orbit test results. For an illustration of this approach, experimental data of the NASA Mini-MAST truss was used. The estimations of modal properties involve lateral bending modes and torsional modes. The results show that distributed parameter models are promising in the parameter estimation of large flexible structures

MobiCacher: Mobility-Aware Content Caching in Small-Cell Networks

Small-cell networks have been proposed to meet the demand of ever growing mobile data traffic. One of the prominent challenges faced by small-cell networks is the lack of sufficient backhaul capacity to connect small-cell base stations (small-BSs) to the core network. We exploit the effective application layer semantics of both spatial and temporal locality to reduce the backhaul traffic. Specifically, small-BSs are equipped with storage facility to cache contents requested by users. As the {\em cache hit ratio} increases, most of the users' requests can be satisfied locally without incurring traffic over the backhaul. To make informed caching decisions, the mobility patterns of users must be carefully considered as users might frequently migrate from one small cell to another. We study the issue of mobility-aware content caching, which is formulated into an optimization problem with the objective to maximize the caching utility. As the problem is NP-complete, we develop a polynomial-time heuristic solution termed {\em MobiCacher} with bounded approximation ratio. We also conduct trace-based simulations to evaluate the performance of {\em MobiCacher}, which show that {\em MobiCacher} yields better caching utility than existing solutions.Comment: Accepted by Globecom 201

A piecewise continuous Timoshenko beam model for the dynamic analysis of tapered beam-like structures

Distributed parameter modeling offers a viable alternative to the finite element approach for modeling large flexible space structures. The introduction of the transfer matrix method into the continuum modeling process provides a very useful tool to facilitate the distributed parameter model applied to some more complex configurations. A uniform Timoshenko beam model for the estimation of the dynamic properties of beam-like structures has given comparable results. But many aeronautical and aerospace structures are comprised of non-uniform sections or sectional properties, such as aircraft wings and satellite antennas. This paper proposes a piecewise continuous Timoshenko beam model which is used for the dynamic analysis of tapered beam-like structures. A tapered beam is divided into several segments of uniform beam elements. Instead of arbitrarily assumed shape functions used in finite element analysis, the closed-form solution of the Timoshenko beam equation is used. Application of the transfer matrix method relates all the elements as a whole. By corresponding boundary conditions and compatible conditions a characteristic equation for the global tapered beam has been developed, from which natural frequencies can be derived. A computer simulation is shown in this paper, and compared with the results obtained from the finite element analysis. While piecewise continuous Timoshenko beam model decreases the number of elements significantly; comparable results to the finite element method are obtained

Current-induced effect on the resistivity of epitaxial thin films of La 0.7Ca 0.3MnO 3 and La 0.85Ba 0.15MnO 3

A study was performed on the current-induced effect on the resistivity of epitaxial thin films of La 0.7Ca 0.3MnO 3 and La 0.85Ba 0.15MnO 3. The peak resistance showed a significant change at different current or current resistance. It was found that for both the compounds the dependence of the measured resistance on current revealed a good linear relationship.published_or_final_versio

Good rectifying characteristic in p–n junctions composed of La0.67Ca0.33MnO3-δ/Nb–0.7 wt %-doped SrTiO3

Simple p–n junctions have been fabricated using a simple heteroepitaxial structure of La0.67Ca0.33MnO3–/Nb-doped SrTiO3. In such junctions, the La0.67Ca0.33MnO3– exhibits semiconductor behavior due to oxygen deficiency, whereas the Nb–0.7 wt %-doped SrTiO3 shows a metal behavior. These junctions demonstrate good rectifying characteristic in a wide temperature range from 5 to 350 K. An intriguing observation is that the rectifying behavior is nearly independent of temperature. © 2003 American Institute of Physics.published_or_final_versio

Computational Control of Flexible Aerospace Systems

The main objective of this project is to establish a distributed parameter modeling technique for structural analysis, parameter estimation, vibration suppression and control synthesis of large flexible aerospace structures. This report concentrates on the research outputs produced in the last two years of the project. The main accomplishments can be summarized as follows. A new version of the PDEMOD Code had been completed. A theoretical investigation of the NASA MSFC two-dimensional ground-based manipulator facility by using distributed parameter modelling technique has been conducted. A new mathematical treatment for dynamic analysis and control of large flexible manipulator systems has been conceived, which may provide a embryonic form of a more sophisticated mathematical model for future modified versions of the PDEMOD Codes