Background: Brain death is a clinical diagnosis that implies irreversible loss of function of the entire brain, including the brainstem and both hemispheres. Based on previous reports, it is not rare for reflex and spontaneous movements to occur in patients during the process of determining brain death. However, reports of the frequency and common types of these movements vary from study to study. Thus, we evaluated adult patients with impending brain death in Korea to determine the frequency and characteristics of reflex and spontaneous movements. Methods: Brain dead patients who were admitted to 15 hospitals in the Yeongnam region (Southeast) of Korea were recruited prospectively from January 2013 to September 2016. All patients met the criteria for brain death as established by the Korea Medical Association. All body movements occurred during the process of diagnosing brain death and were assessed by physicians and trained organ transplant coordinators. The frequency and characteristics of these movements were identified and the demographic and clinical factors of impending brain dead patients with and without these movements were compared. Results: A total of 436 patients who met the criteria for brain death were enrolled during the study period. Of these patients, 74 (17.0%) exhibited either reflex or spontaneous movements. Of this subset, 45 (60.8%) exhibited reflex movements only, 18 (24.3%) exhibited spontaneous movements only, and 11 (14.9%) exhibited both reflex and spontaneous movements. The most common reflex movements were the flexor/extensor plantar response and spinal myoclonus. Of the 74 patients, 52 (70.3%) exhibited one movement of the same pattern and 22 (29.7%) exhibited two or more different movement patterns. In addition, 45 (60.8%) exhibited these movements only on a limited area of the body with the leg being most common (n = 26, 57.8%). Patients with hypoxic brain damage and a higher systolic blood pressure exhibited significantly more reflex or spontaneous movements. Conclusion: Movements associated with brain dead patients are not rare and thus an awareness of these movements is important to brain death diagnosis. Physicians who perform brain death examinations should understand the frequency and characteristics of these movements to reduce delays in determining brain death.

In this study of the access process in analogical problem solving, preschoolers, first graders and third graders repeatedly listened to a variety of similar types of source stories until they could recall them completely. They then listened to a target story, were asked to retrieve the source story, were directed to solve a problem in a target story and to verify their responses. We found the following developmental differences: (1) the child could not access structural similarity at all; or the child could not maintain it until he/she reached a solution to the problem; (2) the child did not access structural similarity at first, but he/she re-accessed it during later processes of problem solving; (3) the child accessed structural similarity from the first and was able to maintain it with sound analogy. We described hypothetical reasons for such differences in analogical problem solving and provided suggestions for further research.

Pumping regimes for water distribution systems have been established to reduce pump operation costs. Optimization of water reservoir networks has been studied extensively for operating pumps efficiently. According to research, optimization reduces pump operation costs by approximately 10–20%. However, comparing economic benefits per country would be too complex because the effects of optimization differ depending on the power cost estimation system of each country and the existing operations. This study presents an optimization algorithm to minimize the operating costs of an entire system via the application of dynamic programming. Case studies were conducted to apply the algorithm to real values in four scenarios. By setting cost minimization as an objective, an optimum water pump operation plan was derived that encompasses operating conditions, variations in water demand, and energy costs. Results showed that operating a standby pump in an existing system can increase the system's efficiency. In addition, even if hourly water consumption remains constant, each case requires its own operating method, because each case has different operational costs. By considering various conditions such as those mentioned in this study, future pump operation schedules can be optimized and stabilized to maintain economic water supply.

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Brain death is a clinical diagnosis that implies irreversible loss of function of the entire brain, including the brainstem and both hemispheres. It is not uncommon for reflex and spontaneous movements to occur in patients with impending brain death during the process of determining brain death. When physicians charged with judging brain death witness such movements during this period, unless they know how common these movements are and what they mean, it will be difficult for them to make an appropriate determination of brain death. Movements following brain death have been reported in previous studies of various types, including cohort studies and case series or reports. However, only a few studies have employed verified diagnostic tools and neurological examinations as a standard protocol when diagnosing brain death. According to previous reports, the frequency of these movements ranges from 19.2% to 75.0% of all brain death cases. These reports have also described which movements are commonly seen. However, it is difficult to determine conclusively where these movements originate, i.e., in the spinal cord or in the cerebral motor cortex, and how such information should be considered in determining brain death. Although limited information is available on the characteristics and pathophysiological mechanism of these movements, it will help physicians to diagnose brain death correctly if they obtain sufficient knowledge about them.