Total solar irradiance measurements from the 1984‐1993 Earth Radiation Budget Satellite (ERBS) active cavity radiometer and 1978‐1993 Nimbus 7 transfer cavity radiometer spacecraft experiments are analyzed to detect the presences of 11‐, 22‐, and 80‐year irradiance variability components. The analyses confirmed the existence of a significant 11‐year irradiance variability component, associated with solar magnetic activity and the sunspot cycle. The analyses also suggest the presence of a 22‐ or 80‐year variability component. The earlier Nimbus 7 and Solar Maximum Mission (SMM) spacecraft irradiance measurements decreased approximately 1.2 and 1.3 Wm−2, respectively, between 1980 and 1986. The Nimbus 7 values increased 1.2 Wm−2 between 1986 and 1989. The ERBS irradiance measurements increased 1.3 Wm−2 during 1986‐1989, and then decreased 0.4 Wm−2 (at an annual rate of 0.14 Wm−2yr−1) during 1990‐1993. Considering the correlations between ERBS, Nimbus 7, and SMM irradiance trends and solar magnetic activity, the total solar irradiance should decrease to minimum levels by 1997 as solar activity decreases to minimum levels, and then increase to maximum levels by the year 2000 as solar activity rises. The ERBS measurements yielded 1365.4 ± 0.7 Wm−2 as the mean irradiance value with measurement accuracies and precisions of 0.2% and 0.02%, respectively. The ERBS mean irradiance value is within 0.2% of the 1367.4, 1365.9, and 1366.9 Wm−2 mean values for the SMM, Upper Atmosphere Research Satellite (UARS), and Space Shuttle Atmospheric Laboratory for Applications and Science (ATLAS 1) Solar Constant (SOLCON) active cavity radiometer spacecraft experiments, respectively. The Nimbus 7 measurements yielded 1372.1 Wm−2 as the mean value with a measurement accuracy of 0.5%. Empirical irradiance model fits, based upon 10.7‐cm solar radio flux (F10) and photometric sunspot index (PSI), were used to assess the quality of the ERBS, Nimbus 7, SMM, and the UARS irradiance data sets and to identify irradiance variability trends which may be caused by drifts or shifts in the spacecraft sensor responses. Comparisons among the fits and measured irradiances indicate that the Nimbus 7 radiometer response shifted by a total of 0.8 Wm−2 between September 1989 and April 1990 and that the ERBS and UARS radiometers each drifted approximately 0.5 Wm−2 during the first 5 months in orbit.

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The contributions of text meaning, new between-word associations, and single-word repetition to priming in text rereading in younger and older adults, and in patients with Alzheimer's disease. (AD), were assessed in Experiment 1. Explicit recognition memory for text was also assessed. Equivalent single-word and between-word priming was observed for all groups, even though patients with AD showed impaired explicit memory for individual words in the text. The contribution of generalized reading task skill to priming in meaningless text rereading in younger adults was assessed in Experiment 2. Generalized reading task skill was also found to contribute to priming. These results reveal 3 mechanisms of priming: new between-word associations for meaningful and meaningless text, individual word repetition for meaningless text, and general task or skill factors for meaningless text. All priming mechanisms appear to be intact in older adults and in patients with AD.

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The Clouds and the Earth's Radiant Energy System (CERES) flight models 1 through 4 instruments were launched aboard NASA's Earth Observing System (EOS) Terra and Aqua spacecraft into 705-km sunsynchronous orbits with 10:30 p.m. and 1:30 a.m. local time equatorial crossing times. With these instruments CERES provides state-of-the-art observations and products related to the earth's radiation budget at the top of the atmosphere (TOA). The archived CERES science data products consist of geolocated and calibrated instantaneous filtered and unfiltered radiances through temporally and spatially averaged TOA, surface, and atmospheric fluxes. CERES-filtered radiance measurements cover three spectral bands: shortwave (0.3-5 mm), total (0.3.100 mm), and an atmospheric window channel (8-12 mm).CERES climate data products realize a factor of 2-4 improvement in calibration accuracy and stability over the previotus Earth Radiation Budget Experiment (ERBE) products. To achieve this improvement there are three editions of data products. Edition 1 generates data products using gain coefficients derived from ground calibrations. After a minimum of four months, the calibration data are examined to remove drifts in the calibration. The data are then reprocessed to produce the edition 2 data products. These products are available for science investigations for which an accuracy of 2% is sufficient. Also, a validation protocol is applied to these products to find problems and develop solutions, after which edition 3 data products will be computed, for which the objectives are calibration stability of better than 0.2% and calibration traceability from ground to flight of 0.25%. This paper reports the status of the radiometric accuracy and stability of the CERES edition 2 instrument data products through April 2007.

The Zwanzig−Mori projection−operator formalism is employed to describe the dynamics of relaxation in a prototypic model well known for its application to a variety of physical problems: a harmonic oscillator coupled to a heat bath. First an exact equation of motion in generalized Langevin form is obtained for G (t), the expectation value of the occupation number of the oscillator, known to be in a definite initial nonequilibrium state. This equation is then solved in the appropriate van Hove weak−coupling, long−time limit for the usual case of physical interest in which the oscillator−bath interaction is linear in the oscillator coordinate. In this case G (t) is found to decay exponentially with a time constant τl = τd/2, where τd is the so called ’’dephasing’’ time, i.e., the time constant associated with the exponentially decaying time correlation function of the oscillator coordinate, 〈Q (0) Q (t) 〉. The approach taken here, which may be easily generalized, leads in a rather natural and straightforward way not only to relations between different relaxation times but also to useful explicit expressions for these times.