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871.
Gabriel K.J. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》1998,86(8):1534-1535
The evolution and maturity of microelectromechanical systems (MEMS) in the coming years will be driven less by captive fabrication facilities and process development and more by innovative, aggressive electromechanical systems design. MEMS is poised to take full advantage of advances in information technology and couple them to advances in other disciplines to drive a fundamentally new approach to electromechanical system design and fabrication. By merging sensing and actuation with computation, MEMS will not only invest existing systems with enhanced capabilities and reliability but also will make possible radically new devices and systems designs that will exploit the miniaturization, multiplicity, and microelectronics of MEMS. For the first time, approaches akin to VLSI electronics can be taken to usher in an equally exciting and productive era of VLSI electromechanics 相似文献
872.
Siberian hamsters (Phodopus sungorus sungorus) undergo photoperiod-induced physiological and behavioral adaptations. These adaptations, including changes in reproductive and metabolic status, are triggered by the pineal gland through the nocturnal secretion of its principal hormone, melatonin. The possible CNS sites of melatonin action determined through radiolabeled melatonin binding include the paraventricular and reuniens nuclei of the thalamus and the suprachiasmatic nucleus (SCN). However, we do not know the mechanisms and circuitry involved in the transmission of melatonin signals. Bilateral electrolytic lesions of the SCN (SCNx) block the responses to short day-like (long duration) melatonin signals delivered daily via the timed infusion paradigm, suggesting that the SCN receives and transmits short-day melatonin signals. The purpose of the present experiment was to answer the following question: are short-day melatonin signals transmitted to other brain structures from the SCN through its dorsomedial/dorsocaudal fiber projections? Pinealectomized adult male hamsters given horizontal knife cuts (kc) just dorsocaudal to the SCN (SCN-kc), sham-kc, or SCNx were given daily subcutaneous short day-like melatonin infusions via the timed infusion paradigm for 6 weeks. Only the hamsters given SCNx exhibited long day-like gonadal, epididymal fat pad, and body masses. Therefore, short day melatonin signals received by the SCN were not transmitted to other areas of the central nervous system through SCN efferents projecting dorsomedially or dorsocaudally. 相似文献
873.
Priout Pierre; Guédon Olivier; Proteau Luc; Gauthier Gabriel M. 《Canadian Metallurgical Quarterly》2002,56(4):253
Determined whether a sensorimotor or cognitive encoding is used to encode a target position and save it into iconic memory. The methodology consisted of disrupting a manual aiming movement to a memorized visual target by displacing the visual field containing the target. The target was presented either centrally or in the right periphery. Participants moved their hand from the left to the right of fixation. The visual field was either stationary throughout the trial or was displaced to the right or left at the extinction of the target or at the start of the hand movement. Results showed three major effects: (1) Vision of the hand during the gesture improved the final accuracy; (2) visual field displacement produced an underestimation of the target distance only when the hand was not visible during the gesture and was always in the same direction displacement; and (3) the effect of the stationary structured visual field on aiming precision when the hand was not visible depended on the distance to the target. These results suggest that a stationary structured visual field is used to support the memory of the target position. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
874.
In seven healthy preterm infants the transcutaneous PO2 was measured during different sleep states. The tcPO2 is lower during active sleep than during quiet sleep and shows a higher variability in active sleep. The incidence of apneic spells, which occur predominantly during active sleep, was not found to be correlated to tcPO2 levels. 相似文献
875.
876.
The 'combined approach' as a requirement of the EC Water Framework Directive pools an emission-based approach with an approach based on environmental quality standards (EQS) to improve European water quality. The implementation of the EQS-based approach poses problems of defining a reference water discharge, defining a distance, where the EQS are obligatory and thus have to be controlled after point discharge, considering incomplete mixing. To elaborate a simple assessment procedure including the aspects mentioned above is the point of discussion in this paper. On the basis of easily available data and references from several European countries, recommendations for an Austrian assessment procedure are presented. 相似文献
877.
Rafael Mayoral Gabriel Lera María Jos Prez-Ilzarbe 《Image and vision computing》2006,24(12):1288-1300
The computation of a scalar correspondence error is the fundamental step in most stereo correspondence algorithms. The quality of the results obtained by the reconstruction algorithm directly depends on the characteristics of such error. We have developed a procedure to evaluate different methods proposed for the computation of the correspondence error. The evaluation is based on exploring the shape of the error surface generated and testing it for uniqueness, isolation and compatibility. The scheme presented makes it possible to recognise the known characteristics of the tested methods for the computation of a correspondence error from the results of the evaluations. Our results show that, for the tested scenes, the evaluation scheme allows us to identify the most appropriate method to compute the correspondence error. 相似文献
878.
Gabriel Beltrn Carmen del Río Sebastin Snchez Leopoldo Martínez 《Journal of the science of food and agriculture》2004,84(13):1783-1790
Olive fruits of three of the most important Spanish and Italian cultivars, ‘Picual’, ‘Hojiblanca’ and ‘Frantoio’, were harvested at bi‐weekly periods during three crop seasons to study their development and ripening process. Fresh and dry weights and ripening index were determined for fruit, while dry matter, oil and moisture contents were determined in both fruit and pulp (flesh). Fruit growth rate and oil accumulation were calculated. Each olive cultivar showed a different ripening pattern, ‘Hojiblanca’ being the last one to maturate. Fruit weight increased, decreasing its growth rate from the middle of November. Dry matter and moisture contents decreased during ripening in pulp and fruit, ‘Hojiblanca’ showing the highest values for both. Oil content, when expressed on a fresh weight basis, increased in all cultivars, although for the last time period showed variations due to climatic conditions. During ripening, oil content on a dry weight basis increased in fruit, but oil biosynthesis in flesh ceased from November. Olive fruits presented lower oil and higher dry matter contents in the year of lowest rainfall. Therefore fruit harvesting should be carried out from the middle of November in order to obtain the highest oil yield and avoid natural fruit drop. Copyright © 2004 Society of Chemical Industry 相似文献
879.
Gabriel Cendejas-Santana Jaime Hinojosa-Torres Victor M. Castaño 《Materials Research Innovations》2002,6(5-6):252-255
We have grown progesterone single crystals from a gradually heated solution in acetone + ethyl ether. Transparent crystals
obtained were analyzed by X-ray diffraction, electron diffraction, infrared and Raman spectroscopy. The X-ray and electron
diffraction show an orthorhombic structure. Spectroscopy confirms that the crystal is constituted by the same components as
the progesterone molecule.
Electronic Publication 相似文献
880.
We introduce a method for the estimation of the mean Lorentzian bandwidth of the component bands in a spectrum. The method is computationally simple, using only the module of the Fourier transform of the spectrum, and its first derivative. Moreover, the presented method does not require knowledge of the number of bands in the spectrum, their band positions, or their band areas. Furthermore, it works on spectra containing Lorentzian bands, as well as Gaussian and Voigtian bands. Therefore, the introduced method seems especially well suited for obtaining a representative Lorentzian width for highly overlapped bands, independent of their number and Lorentzian/Gaussian character. We describe how different experimental limitations (spectral truncation, offset error, presence of noise, etc.) may affect the performance of the method, and when required we propose effective alternatives to minimize their effects. Finally, we show the application of the method to an experimental spectrum: the amide I band of a dry film of the solubilized ADP/ATP carrier. The estimation of the mean Lorentzian width can allow, for instance, for a more objective selection of the deconvolution width in Fourier self-deconvolution, allowing for a more objective and reliable analysis of the amide I band of proteins. The mean Lorentzian width can also be useful to obtain an estimation of the homogenous broadening and vibrational relaxation of the amide I vibration of proteins, without requiring complex pump-probe experiments. 相似文献