This work had three objectives: to improve the reported assignments of the vibrational frequencies in several organoslllcon monomers and oligomers; to assign the vibrational frequencies of polydimethylsiloxane (PDMS); and to relate the vibrational spectra of PDMS to its other physical properties, especially at sub-ambient temperatures. Infrared and Raman spectra were obtained on the title compounds, and five sets of low-temperature IR spectra were obtained on PDMS. Some low-temperature spectra were also taken on the cyclosiloxanes. Assignment of all frequencies was accomplished, although in some cases, e.g., the methyl rocking frequencies at 650–870 cm−1 and the skeletal deformations below 400 cm−1, our confidence in their correctness Is less than complete. The low-temperature study showed striking changes In the IR spectrum of PDMS below its glass transition temperature T8. Bands became sharper and in some cases showed splitting. This behavior is consistent with the concept of polymer motion being frozen below T8. Except for the appearance of a strong, sharp band at 662 cm−1, not much change was seen in the spectrum at the “cold crystallization” point. Possibly the expected spectral changes were swamped by absorption from the more plentiful amorphous portion of the polymer matrix.

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The FACTRETRIEVAL2 test battery, which assesses both retrieval of general information from memory and metacognition about that retrieval, was administered to people before and after a recent expedition to Mount Everest and at extreme altitudes above 6,400 m (higher than any mountain in North America or Europe). The major findings were as follows: First, the same extreme altitudes already known to impair learning did not affect either accuracy or latency of retrieval, and this robustness of retrieval occurred for both recall and forced-choice recognition. Second, extreme altitude did affect metacognition: The climbers showed a decline in their feeling of knowing both while at extreme altitude and after returning to Kathmandu (i.e., both an effect and an aftereffect of extreme altitude). Third, extreme altitude had different effects than alcohol intoxication (previously assessed by Nelson. McSpadden, Fromme, & Marlatt, 1986). Alcohol intoxication affected retrieval without affecting metacognition, whereas extreme altitude affected metacognition without affecting retrieval; this different pattern for extreme altitude versus alcohol intoxication implies that (a) hypoxia does not always yield the same outcome as alcohol intoxication and (b) neither retrieval nor metacognition is strictly more sensitive than the other for detecting changes in independent variables.

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