共查询到20条相似文献,搜索用时 15 毫秒
1.
S Wagner F Deymeer LL Kürz S Benz L Schleithoff F Lehmann-Horn P Serdaro?lu C Ozdemir R Rüdel 《Canadian Metallurgical Quarterly》1998,21(9):1122-1128
Clinical, electrophysiological, and molecular findings are reported for a family with dominant myotonia congenita in which all affected members have experienced long-term fluctuations of the symptom of myotonia. In some patients myotonia is combined with myalgia. The myotonia-causing mutation in this family is in the gene encoding the muscular chloride channel, hCIC-1, predicting the amino acid exchange G200R. We have constructed recombinant DNA vectors for expression of the mutant protein in tsA201 cells and investigation of the properties of the mutant channel. The most prominent alteration was a +100-mV shift of the midpoint of the activation curve. Therefore, within the physiological range the open probability of the mutant channel is markedly smaller than in wild-type. This shift is likely to be responsible for the myotonia in the patients. The fluctuating symptoms of this chloride channelopathy are discussed with respect to short-term fluctuations of myotonia in the sodium channelopathy of potassium-aggravated myotonia. 相似文献
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Jean-Philippe Venot Kiran Jella Luna Bharati Biju George Trent Biggs Parthasaradhi Gangadhara Rao Murali Krishna Gumma Sreedhar Acharya 《Canadian Metallurgical Quarterly》2010,136(9):595-609
In closing river basins where nearly all available water is committed to existing uses, downstream irrigation projects are expected to experience water shortages more frequently. Understanding the scope for resilience and adaptation of large surface irrigation systems is vital to the development of management strategies designed to mitigate the impact of river basin closure on food production and the livelihoods of farmers. A multilevel analysis (farm-level surveys and regional assessment through remote-sensing techniques and statistics) of the dynamics of irrigation and land use in the Nagarjuna Sagar project (South India) in times of changing water availability (2000–2006) highlights that during low-flow years, there is large-scale adoption of rainfed or supplementary irrigated crops that have lower land productivity but higher water productivity, and that a large fraction of land is fallowed. Cropping pattern changes during the drought reveal short-term coping strategies rather than long-term evolutions: after the shock, farmers reverted to their usual cropping patterns during years with adequate canal supplies. For the sequence of water supply fluctuations observed from 2000 to 2006, the Nagarjuna Sagar irrigation system shows a high level of sensitivity to short-term perturbations, but long-term resilience if flows recover. Management strategies accounting for local-level adaptability will be necessary to mitigate the impacts of low-flow years but there is scope for improvement of the performance of the system. 相似文献
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P Munkhammar S Cullen P J?gi M de Leval M Elliott G Norg?rd 《Canadian Metallurgical Quarterly》1998,32(4):1083-1087
Single-unit spike trains recorded from parietal cortex of monkeys performing a tactile short-term memory task show characteristic fluctuations (transitions) in their firing frequency that are related to memory. Spike trains recorded during the memory period, when the animal must retain information for the short term, show a higher rate of such transitions than spike trains recorded during intertrial baseline periods. In the present study, an analysis of multiple temporal resolutions over which these transitions are observed reveals that the memory-related transitions occur most prominently in the 25-50 Hz range. The results of this study suggest that, in the monkey, high frequency fluctuations of neuronal discharge in the parietal cortex are correlated with haptic short-term memory. The presence of such fluctuations are also consistent with theoretical models of short-term memory. 相似文献
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Dealing with others entails both stability and short-term variability of the functions and outcomes of social relationships. The authors argue that patterns of short-term intraindividual variability in social relationships and self-efficacy beliefs contribute interpretable information about social adaptation. On the basis of 23 repeated weekly measurements of a sample of 32 participants ages 56 to 88 years, the authors examined the extent to which fluctuations in perceived relational outcomes are related to fluctuations of social self-efficacy. Results showed that individuals differ systematically in respect to the extent to which they experience and display fluctuations in self-efficacy and availability of social relationships. Moreover, when individuals perceive others to be available across time, social self-efficacy beliefs are stronger and fluctuate less across time. 相似文献
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It is known what the aim is in a complete long-term growth study; the final height is the outcome measure, although the annual height velocity values provide additional information. Strictly, short-term growth studies are also defined in terms of minimum length of observation, i.e. one month, as well as the type of measurement errors to be considered. The poor correlation between short- and long-term growth velocity values has led to the conclusion that the short-term study cannot be interpreted in long-term perspectives, and vice versa. There is a need to debate the way in which results of short-term studies should be interpreted. This is especially important when short-term growth is taken as the outcome measure in a controlled study. Our proposal is that such studies must include information about the growth achieved for a period after the treatment has ended in order to describe possible compensatory growth. Without weighing in some long-term consequences, we may incorrectly document short-term growth as a positive or negative effect of a certain treatment. 相似文献
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"The following three measures of vocabulary performance varying in sensitivity were obtained from groups of short-term schizophrenics, long-term schizophrenics, and normals equated for art and education: gesticulation (nonverbal), conventional vocabulary achievement, and level of verbal communication. No differences were found between the short-term schizophrenics and the normals of any of the measures. The long-term schizophrenics were significantly lower than normals and short-term schizophrenics on all of the measures. The decrement on gesticulation for the long-term schizophrenics was significantly less than that for the other measures." (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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人民币汇率变动对国际黄金价格的影响 总被引:2,自引:0,他引:2
人民币汇率变动对黄金市场有着重要的影响.文中借助统计模型,利用ADF单整检验、Johansen协整检验、误差修正模型以及脉冲响应函数,实证分析了从1994年1月到2005年7月两次汇率改革之间人民币汇率变动对国际黄金价格的影响.研究结果表明,短期黄金价格的波动受到人民币汇率变动的直接影响,人民币汇率和国际黄金价格之间存在着此消彼长的关系. 相似文献
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MC Armeanu JA van Dieten VM Kolb J Schoemaker J de Koning 《Canadian Metallurgical Quarterly》1993,52(15):1311-1318
The effects were studied of in vivo administration of the new opioid antagonist-estrogen hybrid, naltrexone-estrone azine (EH-NX), on subsequent luteinizing hormone-releasing hormone (LHRH)-stimulated luteinizing hormone (LH) release by the pituitary gland in vitro. It is well known that administration of estrogen exerts negative and positive effects on the pituitary LH response to LHRH, respectively after short-term and long-term treatment. Rats were injected subcutaneously with either 17 beta-estradiol-3-benzoate (EB), EH-NX or oil on days 18 and 19 (long-term treatment), and on day 21 (short-term treatment) following ovariectomy. Twenty minutes later the animals were killed and the pituitary glands were incubated in the presence of LHRH (1000 ng/ml) for 4 h. Whereas short-term treatment with EB on day 21 did not affect LH release in vitro, EH-NX significantly decreased the pituitary LH response to LHRH in oil pretreated rats. This inhibitory effect was partially blocked by the opioid antagonist naltrexone. After long-term EB or EH-NX, followed by short-term oil treatment, the pituitary LH response to LHRH was increased considerably, compared to the long-term oil controls. These observations demonstrate that the opioid antagonist estrogen hybrid EH-NX has estrogenic activity at the level of the pituitary gland. This hybridized drug is more effective in time than EB and an equimolar amount of EH (estrone hydrazone) to induce the negative estrogenic effect. 相似文献
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How do anticipated short-term costs affect the likelihood of engaging in an activity that has long-term benefits. Five studies investigated the factors that determine (a) how anticipated short-term costs elicit self-control efforts and (b) how self-control efforts eventually diminish the influence of short-term costs on behavior. The studies manipulated short-term costs (e.g., painful medical procedures) and assessed a variety of self-control strategies (e.g., self-imposed penalties for failure to undergo a test). The results show that short-term costs elicit self-control strategies for self rather than others, before rather than after behavior, when long-term benefits are important rather than unimportant and when the costs are moderate rather than extremely small or large. The results also show that the self-control efforts help people act according to their long-term interests. (PsycINFO Database Record (c) 2011 APA, all rights reserved) 相似文献
11.
Klimstra Theo A.; Luyckx Koen; Hale William A. III; Frijns Tom; van Lier Pol A. C.; Meeus Wim H. J. 《Canadian Metallurgical Quarterly》2010,99(1):191
The present study was aimed at examining one relatively neglected part of the identity formation process: the short-term dynamics of identity formation. The short-term dynamics were assessed by examining (a) the day-to-day course of 2 key dimensions of identity formation (i.e., commitment and reconsideration) and (b) the impact of fluctuations in commitment and reconsideration on subsequent levels of these 2 dimensions. Longitudinal data on 580 early adolescents (54.8% boys, 45.2% girls) were used to test these assertions. The authors found evidence for a commitment-reconsideration dynamic that operated on a day-to-day basis. Furthermore, the findings confirmed E. H. Erikson's (1950) assertion that identity reflects a sense of sameness and continuity as a more stable identity (reflected by little day-to-day fluctuations) was predictive of higher levels of commitment and lower levels of reconsideration. Taken together, the present study underscores the importance of the short-term dynamics of identity formation. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
This article examines the long-term memory of a 73-yr-old brain-damaged patient, AB, who had previously been reported to have problems in the short-term retention of word meanings. The authors found that AB had a problem not only in the short-term but also in the long-term retention of lexical-semantic information. AB, however, had no problem in the long-term retention of other kinds of information (pictures, shapes, propositional information). This pattern of results was interpreted as evidence that lexical-semantic representations have their own specific memory resources that are involved in the retention of the corresponding representations across different time intervals (e.g., they are involved in short-term as well as long-term retention). Implications for models of memory are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Administered the WAIS, the Halstead-Reitan Neuropsychological Test Battery, associated test procedures, and complete neurological evaluations to 140 schizophrenic inpatients. These Ss were subdivided according to 3 criteria: paranoid vs nonparanoid, neurologically normal vs abnormal, and long-term vs short-term institutionalization. Comparisons between groups were made using 3 stepwise discriminant analyses. Although all of these analyses yielded percentages of correct classification that exceeded chance, the greatest accuracy by far was obtained for the long-term vs short-term institutionalization subdivision. Individual tests contributing the most discriminatory power varied from comparison to comparison, with a complex problem-solving test being the best discriminator in the long-term vs short-term comparison and a simple motor test the best discriminator in the other comparisons. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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A short-term implicit memory effect is reported and interpreted as arising within the word recognition system. In Experiment 1, repetition priming in lexical decision was determined for low-frequency words and pseudowords at lags of 0, 1, 2, 3, 4, 5, 9, and 23 intervening items. For words, a large short-term priming component decayed rapidly but smoothly over the first 3 items (8 s) to a stable long-term value. For nonwords, priming dropped to the long-term value with a single intervening item. This Lag x Lexicality interaction was replicated with a naming task in Experiment 2 and with high-frequency words in Experiment 3. Word frequency affected long-term priming but not the size or decay rate of short-term priming, dissociating the two repetition effects. In Experiment 4, an old-new decision task was used to test explicit memory. Parallel word and nonword decay patterns were found, dissociating short-term priming from explicit working memory. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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We empirically examined S. H. Budman and A. S. Gurman's (see record 1984-04498-001) theoretical proposals concerning major differences in the value systems of long- vs. short-term therapists. Ss were 222 randomly selected licensed psychologists who indicated their preferred approach (short-term or long-term). Values were assessed with a scale designed for the study. Overall, results indicate that therapists who prefer a short-term approach are more likely to endorse the proposed values of the short-term therapist than are therapists who prefer a long-term approach. This finding held even after the authors controlled for the significant contributions of theoretical orientation and therapeutic practice variables. Specifically, short-term (vs. long-term) therapists believed more that psychological change could occur outside of therapy and that setting time limits would intensify the therapeutic work. Implications for the practice of brief therapy are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
18.
The aim of this study was to determine the value of antenatal numerical assessment of foetal heart rate variation in the prediction of adverse perinatal outcome in patients undergoing prostaglandin induction of labour at term. Two hundred and seven patients who underwent prostaglandin cervical ripening after 37 weeks gestation for the indications of pregnancy-induced hypertension, foetal growth retardation or post-dates pregnancy were included in this study. Prior to commencement of cervical ripening, a 30-minute cardiotocography tracing was recorded on the System 8000 machine and the long-term and short-term variations were calculated. Forty-three patients (20.8%) had a long-term variation of less than 30 ms; 9 (4.3%) had a short-term variation of less than 3 ms. The sensitivity and positive predictive values of long-term variation in the prediction of admission to neonatal special care unit were 25.6% and 23.2%, respectively. Corresponding values for short-term variation were 2.6% and 11.1%, respectively. The sensitivity and positive predictive values of long-term variation in the prediction of caesarean section for foetal distress were 33.3% and 9.3%, respectively. Corresponding values for short-term variation were 8.3% and 11.1%, respectively. Long-term and short-term variations appeared to be both poor predictors of adverse perinatal outcome. However, of 4 foetuses with both reduced antenatal heart rate variation and who were subsequently delivered by caesarean section for foetal distress in labour, all 4 were admitted to neonatal special care unit (NSCU). Foetuses with intrapartum evidence of foetal distress were more likely to be admitted to NSCU when antenatal foetal heart rate variation was reduced. 相似文献
19.
Robinson Gilbert B.; McNeill Heather A.; Reed Gina D. 《Canadian Metallurgical Quarterly》1993,107(6):988
Compared the long-lasting with the short-lasting effects of kindling the perforant path input to the hippocampal formation on the acquisition of 2 radial maze tasks. Animals in the long-term group were fully kindled (i.e., Stage 5 motor seizures were evoked) prior to a stimulation-free training period. Animals in the short-term group were kindled 30–45 min prior to each learning trial. A 3rd group of animals served as controls and were never kindled. On both 8-arm and 4/8-arm radial maze tasks, learning impairments were apparent only in the short-term group. Thus, the impaired learning is more likely related to the short-term aftereffects of an afterdischarge than to any long-term alterations in the neuronal status of the brain caused by kindling. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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Effects of magnesium sulfate were investigated on fetal heart rate (FHR) baseline, variability, and reactivity in goats. Six chronically catheterized fetuses of Japanese Saanen goat at 125 to 130 days' gestation (term = 147 days) were used. Magnesium sulfate was directly infused to the fetuses. Short-term variability and long-term variability were obtained according to Huey et al. The baseline, reactivity, short-term variability and long-term variability of the FHR were compared between those receiving magnesium sulfate infusions and those receiving vehicle infusions without magnesium sulfate for 4 hr. Two-way analysis of variance (ANOVA) and Duncan's multiple range test was applied for statistical significance. Four hours magnesium sulfate infusion significantly increased fetal plasma concentration of magnesium from 2.4-6.6 mg/dL, without significant changes in fetal respiratory gases and pH values. The baseline FHR was significantly decreased by magnesium infusion compared with that receiving vehicle infusion. The incidence of acceleration, short-term variability, and long-term variability during the fourth hour of magnesium infusion was also significantly decreased compared to a controlled infusion. The time spent by high amplitude phase of short-term variability and that of long-term variability were also significantly reduced. Significant correlation was obtained between the magnesium concentration and incidence of acceleration at fourth hour of magnesium infusion. Four hours infusion of magnesium sulfate significantly decreases baseline FHR, short-term variability, long-term variability, and reactivity in fetal goats at 0.85 gestation. 相似文献