The removal of distractors in a multidistractor complex span task.

Forgetting is an important phenomenon in working memory. Understanding forgetting could offer a window into the very core of cognition. According to the removal hypothesis, forgetting occurs because distractors interfere with memory traces, and this interference can be actively removed. In the decay refresh hypothesis, forgetting occurs because the memory trace decays with time and can be recovered by refreshment. In the present study, a multidistractor complex span task was designed to directly test the cause of forgetting. The free time after a particular distractor and the total free time were manipulated, with the priming effect of the repeated distractor as a detector. The results showed that a longer free time after the first distractor weakened the priming effect, but a longer total free time had no influence. These results supported the removal hypothesis. The forgetting of distractors was not due to decay but due to removal. The trace of a distractor would be removed when it stops being processed. The removal of a distractor occurs when individuals have free time directly after it, whereas the free time after another distractor is not beneficial.

Three Gorges Dam alters the Changjiang (Yangtze) river water cycle in the dry seasons: Evidence from H-O isotopes.

As the largest hydropower project in the world, the Three Gorges Dam (TGD) has attracted great concerns in terms of its impact on the Changjiang (Yangtze) River and coastal marine environments. In this study, we measured or collected the H-O isotopic data of river water, groundwater and precipitation in the mid-lower Changjiang catchment during the dry seasons of recent years. The aim was to investigate the changes of river water cycle in response to the impoundment of the TGD. Isotopic evidences suggested that the mid-lower Changjiang river water was ultimately derived from precipitation, but dominated by the mixing of different water masses with variable sources and isotopic signals as well. The isotopic parameter "deuterium excess" (d-excess) yielded large fluctuations along the mid-lower mainstream during the initial stage of the TGD impoundment, which was inherited from the upstream water with inhomogeneous isotopic signals. However, as the reservoir water level rising to the present stage, small variability of d-excess was observed along the mid-lower mainstream. This discrepancy could be explained that the TGD impoundment had significantly altered the water cycle downstream the dam, with the rising water level increasing the residence time and enhancing the mixing of reservoir water derived from upstream. This eventually resulted in the homogenization of reservoir water, and thus small fluctuations of d-excess downstream the dam after the quasi-normal stage (2008 to present). We infer that the retention effect of large reservoirs has greatly buffered the d-excess natural variability of water cycle in large river systems. Nevertheless, more research attention has to be paid to the damming effect on the water cycle in the river, estuarine and coastal areas, especially during the dry seasons.

General anesthesia in a juvenile with attention-deficit hyperactivity disorder accompanied by long-term use of methylphenidate (Concerta).

Methylphenidate, a central stimulant, is used in the treatment of individuals who have attention-deficit hyperactivity disorder (ADHD). ADHD is a notorious worldwide disorder with a prevalence rate of 8-12% in schoolchildren, which is characterized by hyperactivity, impulsivity, and inattention. Currently, there have been few reports in the anesthetic literature examining ADHD patients who have had long-term use of methylphenidate, especially the extended-release formulation. Here, we report a case of a 14-year-old boy with ADHD treated chronically with the long-acting form of methylphenidate (Concerta), and who was scheduled to receive orthopedic surgery under general anesthesia. No significant problems or fluctuations in hemodynamics were encountered during anesthesia induction, maintenance, and emergence. The patient made an uncomplicated recovery and was discharged 3 days later without incident.