Integrated satellite-HAP systems

Thus far, high-altitude platform (HAP)-based systems have been mainly conceived as an alternative to satellites for complementing the terrestrial network. This article aims to show that HAP should no longer be seen as a competitor technology by investors of satellites, but as a key element for an efficient hybrid terrestrial-satellite communication system. Two integrated HAP-satellite scenarios are presented, in which the HAP is used to overcome some of the shortcomings of satellite-based communications. Moreover, it is shown that the integration of HAPs with satellite systems can be used to provide more efficient fleet-management and traffic-control services and more powerful data-relay systems.     

ZnO nanocones: Solvothermal synthesis and photoluminescence properties

Ellipsoidal and prism shaped ZnO nanocrystals with hexagonal cross-sections have been synthesized by a simple solvothermal process. The ellipsoidal ZnO nanocrystals possessed a unique hexagonal cross-section having two sharp pointed ends and a flattened central part. The well faceted prism like particles resembled hexagonal cones in their shape. Dimensions of the nanocrystals increased systematically with the increase in the synthesis temperature. The synthesized nanocrystals exhibited near band edge UV emission centered at ～400 nm. An additional defect related green emission band at ～500 nm was observed from the samples synthesized at higher temperatures.     

Evaluation of castor (Ricinus communis) seed cake in the total mixed ration for sheep

BACKGROUND: Castor (Ricinus communis) seed cake (CSC), a byproduct of the vegetable‐oil industry, contains fairly good amounts of protein (crude protein, 290–390 g kg^?1) which could be a suitable substitute of conventional oil cakes like soybean meal (SBM) in livestock diets but for the presence of a toxic glycoprotein, ricin. Efforts were, therefore, made to determine the feasibility of feeding CSC as such or after detoxification with lime (4%, wt/wt) by incorporating it into a total mixed ration (TMR) containing 65 and 35 parts ragi (Eleucine coracana) straw and concentrate mixture, respectively, with 11 g kg^?1 CP and 50 g kg^?1 TDN in which the SBM of a control diet was isonitrogenously replaced with either raw or lime‐treated CSC in test diets. The control and two test TMRs were fed to 24 sheep, respectively, divided at random into three dietary groups having equal number of animals for 150 days. RESULTS: Although lime treatment had a positive effect in reducing ricin by 58%, no adverse effect could be noticed by feeding raw or lime‐treated CSC in terms of body weight changes, macro‐ and micro‐nutrient utilisation, blood biochemical and mineral profile, rumen fermentation pattern, carcass traits, except the level of plasma immunoglobulins which was significantly (P < 0.05) higher in sheep fed CSC diets. No pathological lesions could be noticed in the tissues of visceral organs due to feeding the raw or treated CSC. CONCLUSIONS: The findings suggest no adverse effect in the nutritional performance of adult sheep due to feeding the raw or treated CSC when incorporated into TMRs, probably due to a dilution of the ricin concentration or the development of immunity to the glycoprotein ricin, warranting long‐term growth‐cum‐production studies. Copyright © 2008 Society of Chemical Industry     

Synthesis of Fe-Si-B-Mn-based nanocrystalline magnetic alloys with large coercivity by high energy ball milling

Alloys of Fe-Si-B with varying compositions of Mn were prepared using high energy planetary ball mill for maximum duration of 120 h. X-ray diffraction (XRD) analysis suggests that Si gets mostly dissolved into Fe after 80 h of milling for all compositions. The residual Si was found to form an intermetallic Fe₃Si. The dissolution was further confirmed from the field emission scanning electron microscopy/energy dispersive X-ray analysis (FE-SEM/EDX). With increased milling time, the lattice parameter and lattice strain are found to increase. However, the crystallite size decreases from micrometer (75–95 μm) to nanometer (10–20 nm). Mössbauer spectra analysis suggests the presence of essentially ferromagnetic phases with small percentage of super paramagnetic phase in the system. The saturation magnetization (M _s), remanance (M _r) and coercivity (H _c) values for Fe-0Mn sample after 120 h of milling were 96.4 Am²/kg, 11.5 Am²/kg and 12.42 k Am^?1, respectively. However, for Fe-10Mn-5Cu sample the M _s, H _c and M _r values were found to be 101.9 Am²/kg, 10.98 kA/m and 12.4 Am²/kg, respectively. The higher value of magnetization could be attributed to the favourable coupling between Mn and Cu.     

Novel Systems Modeling Methodology in Comparative Microbial Metabolomics: Identifying Key Enzymes and Metabolites Implicated in Autism Spectrum Disorders

Autism spectrum disorders are a group of mental illnesses highly correlated with gastrointestinal dysfunction. Recent studies have shown that there may be one or more microbial “fingerprints” in terms of the composition characterizing individuals with autism, which could be used for diagnostic purposes. This paper proposes a computational approach whereby metagenomes characteristic of “healthy” and autistic individuals are artificially constructed via genomic information, analyzed for the enzymes coded within, and then these enzymes are compared in detail. This is a text mining application. A custom-designed online application was built and used for the comparative metabolomics study and made publically available. Several of the enzyme-catalyzing reactions involved with the amino acid glutamate were curiously missing from the “autism” microbiome and were coded within almost every organism included in the “control” microbiome. Interestingly, there exists a leading hypothesis regarding autism and glutamate involving a neurological excitation/inhibition imbalance; but the association with this study is unclear. The results included data on the transsulfuration and transmethylation pathways, involved with oxidative stress, also of importance to autism. The results from this study are in alignment with leading hypotheses in the field, which is impressive, considering the purely in silico nature of this study. The present study provides new insight into the complex metabolic interactions underlying autism, and this novel methodology has potential to be useful for developing new hypotheses. However, limitations include sparse genome data availability and conflicting literature experimental data. We believe our software tool and methodology has potential for having great utility as data become more available, comprehensive and reliable.     

Abundance of cyclo (His-Pro)-like immunoreactivity in the brain of TRH-deficient mice

Cyclo(His-Pro) or CHP was initially discovered as a metabolite of thyrotropin-releasing hormone (TRH) resulting from the action of the enzyme Pyroglutamyl aminopeptidase. Physiologic and pharmacologic studies that followed this initial discovery provided indirect evidence that all CHP may not be derived from TRH. However, the recent availability of a TRH-deficient mouse has made it possible to reinvestigate whether CHP is derived from TRH. In the present study, we examined distribution of CHP and TRH in TRH-deficient mice. Northern blot analysis confirmed the absence of preproTRH mRNA in both the hypothalamus and the cortex of TRH-deficient mice. Brains from the wild-type and TRH-deficient mice were dissected into 7 regions, and TRH and CHP concentrations were determined by specific radioimmunoassay (RIA) in each region. Whereas TRH was identified in all regions of the wild-type brain, with the highest concentration in the hypothalamus, no detectable TRH was observed in any region in the TRH-deficient mice. While CHP-like immunoreactivity (CHP-LI) was present in all regions in the wild-type brain, its concentration was reduced by approximately 50% in the hypothalamus and cerebral cortex of TRH-deficient mice, with no change in other brain regions. Furthermore, the CHP-LI present in the brain of TRH-deficient mice was immunologically and chromatographically identical to synthetic CHP. These findings strongly suggest that a portion of the CHP in the brain is derived from sources other than TRH.     

Compressive property of liquid silicon (infiltrated) boron carbide

Compressive deformation of reaction bonded boron carbide has been carried out over a strain rate range 10⁻⁴ to 10⁻² s⁻¹. The maximum compressive strength of reaction bonded boron carbide at strain rate of 10⁻⁴ s⁻¹ is 370 MPa and 470 MPa at strain rate of 10⁻² s⁻¹. It is not possible to carryout quasi-static compression test at very higher strain rates (≥ 10² s⁻¹). However, the data generated at low strain rates can be extrapolated to higher strain rates and this data correlate well with the experimental compressive strength values generated by dynamic compression tests.     

Finding structure in noisy text: topic classification and unsupervised clustering

This paper addresses two types of classification of noisy, unstructured text such as newsgroup messages: (1) spotting messages containing topics of interest, and (2) automatic conceptual organization of messages without prior knowledge of topics of interest. In addition to applying our hidden Markov model methodology to spotting topics of interest in newsgroup messages, we present a robust methodology for rejecting messages which are off-topic. We describe a novel approach for automatically organizing a large, unstructured collection of messages. The approach applies an unsupervised topic clustering procedure to generate a hierarchical tree of topics.     

A scatter search approach for general flowshop scheduling problem

This paper proposes a new evolutionary technique called scatter search for scheduling problems of a general flow-shop. Scatter search (SS) is applied to this problem as it is able to provide a wide exploration of the search space through intensification and diversification. In addition it has a unifying principle for joining solutions which exploit the adaptive memory principle to avoid generating or incorporating duplicate solutions at various stages of the problem. This methodology provides substantially better results than the Tabu search approach of Nowicki and Smutnicki (Manage Sci 42(6):797–813, 1996) and Jain and Meeran (Comput Oper Res 29:1873–1901, 2002). The proposed framework achieves an average deviation of 14.25% from the lower bound solution of benchmark problems of Demirkol et al. (Eur J Oper Res 109(1):137–141, 1998), while the scatter search technique gives the best solutions for 32 of 40 of their benchmark problems.