115 research outputs found
Changes in the Seasonality of Precipitation over the Contiguous USA
Consequences of possible changes in annual total precipitation are dictated, in part, by the timing of precipitation events and changes therein. Herein, we investigated historical changes in precipitation seasonality over the US using observed station precipitation records to compute a standard seasonality index (SI) and the day of year on which certain percentiles of the annual total precipitation were achieved (percentile day of year). The mean SI from the majority of stations exhibited no difference in 1971–2000 relative to 30-year periods earlier in the century. However, analysis of the day of year on which certain percentiles of annual total precipitation were achieved indicated spatially coherent patterns of change. In some regions, the mean day of the year on which the 50th percentile of annual precipitation was achieved differed by 20–30 days between 1971–2000 and both 1911–1940 and 1941–1970. Output from the 10-Atmosphere-Ocean General Circulation Models (AOGCM) simulations of 1971–2000, 2046–2065, and 2081–2100 was used to determine whether AOGCMs are capable of representing the seasonal distribution of precipitation and to examine possible future changes. Many of the AOGCMs qualitatively captured spatial patterns of seasonality during 1971–2000, but there was considerable divergence between AOGCMs in terms of future changes. In both the west and southeast, 7 of 10 AOGCMs indicated later attainment of the 50th percentile accumulation in 2047–2065, implying a possible reversal of the twentieth-century tendency toward relative increases in precipitation receipt during winter and early spring over the southeast. However, this is also a region characterized by considerable interannual variability in the percentile day of year during the historical period
Diferencias individuales en cognición: una nueva aproximación a la inteligencia
The existence of individual differences in mental functioning is a reality. Its span and nature
have such important consequences in our culture that society demands a way to measure intelligence.
Nevertheless, some psychologists think that intelligence tests are just a measure instrument that does
not represent properly a formal model of the mental processes dinamics. This article offers some
theoric and empiric arguments against the separation of tests and cognitive theories. The authors think
that the approach between the experimental psychologist and the psychometrician may bring
substantial benefits; available data indicates how this may be possible.El hecho de las diferencias individuales en el funcionamiento mental es una realidad. Su
amplitud y naturaleza tiene unas consecuencias tan importantes en nuestra cultura que hace que la
sociedad demande una forma de medir la inteligencia. No obstante algunos psicólogos opinan que los
tests de inteligencia son un instrumento de medida que no representa adecuadamente un modelo
formal de la dinámica de los procesos de pensamiento. Este artÃculo consiste en una serie de
argumentos teóricos y empÃricos contra la separación de los tests y las teorÃas cognitivas. Se piensa,
en este artÃculo, que se pueden producir substanciales beneficios del acercamiento entre el psicólogo
experimental y el psicómetra; los datos disponibles indican cómo se puede producir este
acercamiento
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