The visuo-motor pathway in the local circuit of the rat superior colliculus

Intrinsic circuit of the superior colliculus (SC), in particular the pathway from the optic tract (OT) to neurons in the intermediate layer (SGI), was investigated by whole-cell patch-clamp recording in slice preparations obtained from 17- to 24-d-old rats. Stimulation of the OT induced monosynaptic EPSPs in neurons in the superficial gray layer (SGS) and the optic layer (SO), and disynaptic or polysynaptic EPSPs in a majority of SGI neurons. Stimulation of the SGS induced monosynaptic or oligosynaptic EPSPs in the SGI neurons. Both the monosynaptic EPSPs induced in the SGS/SO neurons by stimulation of the OT and those induced in the SGI neurons by stimulation of the SGS were mediated by AMPA- and NMDA-type glutamate receptors. Thus, we have clarified the existence of the glutamatergic excitatory pathway from the OT to the SGI neurons via SGS and SO neurons. The EPSPs in the SGI neurons induced by stimulation of the OT or SGS were remarkably enhanced by bicuculline, suggesting that the signal transmission in this pathway is under strong suppression by the GABAergic system.     

Micropolar fluid lubrication of one-dimensional journal bearings

A study of the characteristics of one-dimensional journal bearings shows that the load capacity increases and the coefficient of friction decreases as the parameter $\text{μ}{}_1$, which characterizes the microstructure of the base oil due to the presence of additives, increases. The time of approach increases as the parameter $\text{μ}{}_1$ increases.     

Axial view inductively coupled plasma optical emission spectrometry for monitoring tin concentration in canned tomato sauce samples

In this study it was evaluated the variation of tin concentration in function of storage time in canned food samples by using an axial view inductively coupled plasma optical emission spectrometry (AX ICP OES). The effect of various parameters of the ICP OES, such as analytical lines, sample introduction systems and interferences were investigated. Eight emission lines for tin were tested, but only 283.998 nm line was found to be robust enough with respect to interferences and sensitivity, presenting a limit of quantification of 0.094 mg kg⁻¹. A concentric nebuliser combined with a cyclonic chamber has shown better sensitivity than a V-groove nebuliser. Tin was determined in canned tomato sauce stored at room temperature (20.0 ± 1.8 °C) for 0, 30, 60, 90, 120 and 150 days. After 150 days, tin contents increased in the 43-91% range. Despite an increase of almost 100% for one sample, tin contents are well below the maximum level allowed by Agência Nacional de Vigilância Sanitária (ANVISA) regulation of 250 mg kg⁻¹.     

MATCHING OF SEPARATELY EXCITED DC MOTORS TO PHOTOVOLTAIC GENERATORS FOR MAXIMUM POWER OUTPUT

This paper addresses the matching of separately excited dc motors to photovoltaic generators (PVG) for maximum power output. The dc motor is used to drive a centrifugal water pump. A PVG is a nonlinear device having insolation dependent I–V (current–voltage) characteristic, and hence a natural mismatch exists between the motor loads and the PVG. Therefore, considering the high initial cost of PVG, it is of vital importance to develop an appropriate matching process, to utilize PVG efficiently. In this article a procedure is developed to express the field current of the motor directly in terms of the maximum power point current and voltage of the PVG. It is shown that by adjusting the field current according to the developed relation, the motor is forced to follow the maximum power trajectory of the PVG, i.e. the input power of the motor is always equal to the maximum output power of the PVG at any available solar insolation. The effect of temperature on the I–V characteristic of the PVG is neglected at this stage. Finally a general expression is proposed relating the optimum field current directly to the available insolation level, which may be used as base for best matching.     

Thermal properties of automotive polymers III – Thermal characteristics and flammability of fire retardant polymers

Thermal properties and flammability behavior of two grades of fire retardant polypropylene and nylon 66, and their base resins were determined. A nylon 6 base polymer and a nano-composite based on that polymer were also analyzed. Thermal gravimetric analysis showed more complex degradation patterns for the fire retardant grades as compared to the base resin. This was attributed to decomposition of ingredients present in the fire retardant. Degradation of polypropylene in air started at about 100°C lower temperature than degradation in nitrogen. For nylon, the degradation in both atmospheres occurred at approximately the same temperature. Modulated Differential Scanning Calorimetry (MDSC) measurements were used to determine melting and glass transition temperatures, heats of fusion, heat capacity and thermal conductivity. Both phosphorus-based and halogen-based fire retardants modified the ignition, propagation, and melt-dripping behavior of nylon and polypropylene during burning. Incorporation of a nano-filler was found to be ineffective in imparting fire retardancy to nylon 6. Performance of these materials will have to be evaluated in actual vehicle applications and fire exposures before use on a broad scale basis. Received: 25 August 2000 / Reviewed and accepted: 28 August 2000     

Characteristics of non-newtonian power law lubricants in step bearings and hydrostatic step seals

The effects of stepped film-thickness on the various characteristics of squeeze films, conical bearings and hydrostatic step seals, using a power law fluid as lubricant have been investigated. It has been shown that the load capacities of squeeze film bearings decrease and those of conical bearings and step seals increase, with the increase in the step height. With a hydrostatic step seal, the load capacity increases as the flow behaviour index of the power law fluid increases.     

A meeting with clay: Individual narratives, self-reflection, and action.

The arts-based qualitative research presented in this article explores the interaction between nonartists and a specific art material, clay, and on reflection, the meaning that they make from this interaction. The aspect of meaning making focused on relates to a typology of thinking and doing strategies that emerged from the research. Thinking and doing are seen as 2 aspects of a creative process here with clay, which are interdependent. The thinking category encompasses 4 groups in which the participants employ different modes of thinking strategies. Different modes of thinking create a different kind of doing with the material. These "dialogues" between creator and material can be seen to exemplify individual ways of "making sense" in the interaction between sensing, feeling, thinking, and doing; and the material, in which structure, process, content, and meaning intertwine. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Attenuation measurement of cylindrical dielectric-rod waveguide

Measurements have been made of the attenuation coefficient of cylindrical dielectric-rod waveguide by a transmission method at 100 GHz. An 8 dB/m attenuation coefficient was obtained, caused half and half by the absorption due to losses in the dielectric and by the scattering due to irregularities and inhomogeneities in the dielectric.