Can reducing inequality reduce the disutility of the poor?

Even though many early workers had suggested the use of lower voltages to increase topographic contrast and to reduce specimen charging and beam damage, we did not usually operate in the conventional scanning electron microscope at low voltage because of the poor resolution, especially of bioligical specimens. However, the development of the “in-lens” field emission scanning electron microscope (FESEM) has led to marked inprovement in resolution, especially in the range of 1-5 kV, within the past year. The probe size has been cumulated to be 0.7nm in diameter at 30kV and about 3nm at 1kV. We have been trying to develop techniques to use this in-lens FESEM at low voltage (LVSEM) for direct observation of totally uncoated biological specimens and have developed the LVSEM method for the biological field.

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Artefacts in the x-ray microanalysis of frozen-hydrated biological samples

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100127724 ◽

1987 ◽

Vol 45 ◽

pp. 658-659

Author(s):

Patrick Echlin

Keyword(s):

Electron Scattering ◽

Biological Samples ◽

Fracture Face ◽

Detailed Structure ◽

X Ray ◽

Morphological Appearance ◽

The Poor ◽

Freeze Dried

A number of papers have appeared recently which purport to have carried out x-ray microanalysis on fully frozen hydrated samples. It is important to establish reliable criteria to be certain that a sample is in a fully hydrated state. The morphological appearance of the sample is an obvious parameter because fully hydrated samples lack the detailed structure seen in their freeze dried counterparts. The electron scattering by ice within a frozen-hydrated section and from the surface of a frozen-hydrated fracture face obscures cellular detail. (Fig. 1G and 1H.) However, the morphological appearance alone can be quite deceptive for as Figures 1E and 1F show, parts of frozen-dried samples may also have the poor morphology normally associated with fully hydrated samples. It is only when one examines the x-ray spectra that an assurance can be given that the sample is fully hydrated.

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Influence of the Acoustic Reflex on Vowel Recognition

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.2903.420 ◽

1986 ◽

Vol 29 (3) ◽

pp. 420-424 ◽

Cited By ~ 4

Author(s):

Michael Dorman ◽

Ingrid Cedar ◽

Maureen Hannley ◽

Marjorie Leek ◽

Julie Mapes Lindholm

Keyword(s):

Auditory System ◽

Sound Pressure ◽

Dynamic Range ◽

Recognition Accuracy ◽

Pressure Level ◽

Acoustic Reflex ◽

The Poor ◽

Stapedial Reflex ◽

Vowel Recognition ◽

High Sound

Computer synthesized vowels of 50- and 300-ms duration were presented to normal-hearing listeners at a moderate and high sound pressure level (SPL). Presentation at the high SPL resulted in poor recognition accuracy for vowels of a duration (50 ms) shorter than the latency of the acoustic stapedial reflex. Presentation level had no effect on recognition accuracy for vowels of sufficient duration (300 ms) to elicit the reflex. The poor recognition accuracy for the brief, high intensity vowels was significantly improved when the reflex was preactivated. These results demonstrate the importance of the acoustic reflex in extending the dynamic range of the auditory system for speech recognition.

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