Learning Perception for Indoor Robot Navigation with a Hybrid Hidden Markov Model/Recurrent Neural Networks Approach

This paper introduces a hybrid system for modeling, learning and recognition of sequences of 'states' in indoor robot navigation. States are broadly defined as local relevant situations (in the real world) in which the robot happens to be during the navigation. The hybrid is based on parallel recurrent neural networks trained to perform a posteriori state probability estimates of an underlying hidden Markov model (HMM) given a sequence of sensory (e.g. sonar) observations. Discriminative training is accomplished in a supervised manner, using gradient-descent. Recognition is carried out either in a dynamic programming framework, i.e. searching the maximum a posteriori probability of state-posteriors along paths of the HMM, or in real time. The approach is suitable for navigation and for map learning. Experiments of learning and recognition of noisy sequences acquired by a mobile robot equipped with 16 sonars are presented.     

Thyroid hormone induces protein secretion and morphological changes in astroglial cells with an increase in expression of glial fibrillary acidic protein

Degradation and utilization of protein by Prevotella ruminicola B1(4), a proteolytic bacterium that is prominent in the rumen, was examined. In preliminary experiments, proteinaceous N sources produced faster growth rates than did NH4Cl, based on changes in optical density over time. However, ammonium chloride produced a greater maximum cell density than did proteinaceous N sources. Of the proteinaceous N sources, an enzymatic hydrolysate of soybean protein with a relative peptide size of 3 AA residues produced a greater growth rate and maximum cell density compared with the other proteinaceous N sources. Further experiments revealed that P. ruminicola B1(4) grew faster and to a greater final dry weight with soybean protein than with casein. Degradation of both proteins was low as was indicated by the slow disappearance of soluble protein, low concentrations of free AA and peptides, and the decrease in ammonia concentrations over time. Patterns of degradation did differ between the two proteins, however. Accumulation of peptides and free AA from soybean protein peaked 2 h earlier than those from casein, and concentrations of free AA and peptides from soybean protein were lower on average than those from casein. Prevotella ruminicola B1(4) preferentially utilized Asp, Ile, Leu, Lys, and Arg from soybean protein compared with casein. The relative size of peptides that accumulated from both proteins, as determined by the ratio of ninhydrin reaction after HCl hydrolysis to ninhydrin reaction before HCl hydrolysis, suggested that part of the proteolytic activity of P. ruminicola B1(4) is a dipeptidase. Our findings suggest that P. ruminicola may have a greater impact on peptide degradation than on protein degradation in the rumen.     

Liquid crystal crown ether derived from cyclic tetramer of epichlorohydrin

Summary A liquid crystal crown ether is obtained by chemical modification of the cyclic tetramer derived from epichlorohydrin with sodium 4-cyano-4′-biphenoxide. The crown ether exhibits a nematic mesophase and a high glass transition temperature.     

Involvement of the IP-10 chemokine in sarcoid granulomatous reactions

The accumulation of T cells and monocytes at sites of ongoing inflammation represents the earliest step in the series of events that lead to granuloma formation in sarcoidosis. In this study, we evaluated the pulmonary production of IFN-inducible protein 10 (IP-10), a CXC chemokine that stimulates the directional migration of activated T cells. Striking levels of IP-10 were demonstrated in the bronchoalveolar lavage (BAL) fluid of 24 patients with pulmonary sarcoidosis and lymphocytic alveolitis, as compared with patients with inactive disease or control subjects. A positive correlation was demonstrated between IP-10 levels and the number of sarcoid CD45R0+/CD4+ cells in the BAL. Immunochemistry, performed with an anti-human IP-10 polyclonal Ab in lymph nodes displaying prominent sarcoid granulomas, showed that cells bearing IP-10 were mainly epithelioid cells and CD68+ macrophages located inside granulomatous areas. Macrophages recovered from the BAL of sarcoid patients stained positive for IP-10 protein. Furthermore, alveolar macrophages isolated from sarcoid patients with T cell alveolitis and cultured for 24 h in presence of IFN-gamma secreted definite levels of IP-10 capable of inducing T cell chemiotaxis. Interestingly, alveolar lymphocytes recovered from patients with active sarcoidosis were CD4+ T cells expressing Th1 cytokines (IL-2 and IFN-gamma) and high levels of CXCR3. Taken together, these data suggest the potential role of IP-10 in regulating the migration and activation of T cells toward sites of sarcoid inflammatory process and the consequent granuloma formation.     

Surfactant Micellar Solutions as Alternative Solvents for Microwave-Assisted Extraction of Polycyclic Aromatic Hydrocarbons from a Spiked River Sediment

A procedure to extract polycyclic aromatic hydrocarbons (PAHs) from a contaminated river sediment is discussed; this combines short extraction times obtained by microwave energy with the peculiar solvent capability of aqueous micellar solutions. The technique, named microwave-assisted micellar extraction (MAME), was tested for the extraction of 11 PAHs from a spiked river sediment using polyoxyethylene (23) dodecyl ether (Brij 35), polyoxyethylene (10) dodecyl ether (C 12 E 10 ) or cetyl trimethylammonium bromide (CTAB). Different temperatures and extraction times were explored to establish whether this method has merit. Comparative measurements were made using sonication and Soxhlet extraction with acetone-hexane. Generally, Soxhlet extraction was revealed to be the most effective method to extract the PAHs from the solid matrix, with percent of recovery ranging from 92% to 102%. Nevertheless, high recoveries were also achieved by MAME using C 12 E 10 ; in fact, with only the exception of indeno[1,2,3- cd ]pyrene, the differences between recoveries obtained by MAME and Soxhlet extractions were below 10% for all the considered compounds.     

Lubrication with Oil-Compatible Polymer Brushes

A polymer-brush-based, surface-modification strategy for friction and wear reduction in hard contact under boundary-lubrication conditions is proposed, specifically for a non-aqueous environment. Surface-initiated atom-transfer radical polymerization was employed for the synthesis of three different oil-compatible, hydrophobic polymer brushes based on alkyl methacrylates. This study presents polymerization kinetics, chemical characterization by means of Fourier-transform infrared spectroscopy and surface morphologies observed in atomic force microscopy. The lubrication properties of the anchored polymers were evaluated macroscopically by means of ball-on-disk methods and on the nanonewton scale by lateral force microscopy and showed significant reduction in friction up to contact pressures as high as 460 MPa. The frictional response of surface-grafted polymers is shown to depend strongly on the compatibility of the polymer with the chosen lubricating fluid.     

Photocatalytic degradation of aromatic sulfonates present in industrial percolates

Photocatalytic treatment in the presence of aqueous TiO₂ suspensions was applied to an aqueous percolate containing various hydrophilic aromatic pollutants, in particular naphthalene sulfonates. A preliminary feasibility study was accomplished on standards of pure compounds, for which a degradation rate trend inversely proportional to the sulfonation degree was found, demonstrating the important role played by the substrate adsorption on semiconductor particles. The evolution of primary processes, the abatement of TOC and the release of sulfate were monitored. Further experiments performed on samples of percolates taken from an abandoned industrial site demonstrated the suitability of photocatalysis for the effective destruction and mineralization of the investigated contaminants in these complex matrices after a few hours irradiation.     

Assessment of dietary intake of patulin from baby foods

Patulin is a mycotoxin produced by microscopic fungi belonging to the Penicillium and Aspergillus genera, frequently detectable in moldy fruits and their derivatives fruit products. The EC Regulation 1881/06 has imposed the limit for the presence of patulin equal to 10 μg/kg or 10 μg/L in baby food on the basis of a PMTDI of 0.4 μg/kg bw set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA). A total of 120 homogenized baby foods were analyzed to evaluate the exposure of baby and children to patulin through the consumption of these products. None of examined samples has shown a toxin concentration above the limit imposed by the law, however a PAT concentration equal to 9 μg/kg was found in 22 samples, slightly below the fixed limit. The presence of patulin in marketed baby food can be regarded as a parameter indicative of the quality of raw materials used.     

The evaluation of online courses

Abstract Given the special characteristics of online courses, their quantitative/qualitative evaluation calls for the adoption of specific procedures to assess both the learning process and the participant performance. This paper seeks to shed light on the aspects and issues involved in the evaluation of online courses, focusing on the peculiarities that distinguish such evaluation from that of traditional distance education. Subsequently, a methodological approach will be proposed that was developed and tested during evaluation of online courses for in‐service teacher training and for training of staff in small and medium‐sized enterprises.