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141.
Predictions from a cognitive schema model of anxiety were tested by comparing generally anxious patients and normal controls on their incidental recall of positive and negative, threatening and nonthreatening, self- and other-referenced words. There was no evidence of a self-referent recall bias favoring negative or threatening words in anxiety. Contrary to expectation, the results indicated relatively poorer memory for threatening material in anxious patients. We argue that the cognitive schema model could not adequately account for these and other recent research findings and suggest an alternative formulation of information-processing biases in anxiety. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
142.
Two studies investigated the effects of conditioning to masked stimuli on visuospatial attention. During the conditioning phase, masked snakes and spiders were paired with a burst of white noise, or paired with an innocuous tone, in the conditioned stimulus (CS)+ and CS- conditions, respectively. Attentional allocation to the CSs was then assessed with a visual probe task, in which the CSs were presented unmasked (Experiment 1) or both unmasked and masked (Experiment 2), together with fear-irrelevant control stimuli (flowers and mushrooms). In Experiment 1, participants preferentially allocated attention to CS+ relative to control stimuli. Experiment 2 suggested that this attentional bias depended on the perceived aversiveness of the unconditioned stimulus and did not require conscious recognition of the CSs during both acquisition and expression. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
143.
Differential activation of ERK and JNK mitogen-activated protein kinases by Raf-1 and MEKK 总被引:8,自引:0,他引:8
A Minden A Lin M McMahon C Lange-Carter B Dérijard RJ Davis GL Johnson M Karin 《Canadian Metallurgical Quarterly》1994,266(5191):1719-1723
Growth factors activate mitogen-activated protein kinases (MAPKs), including extracellular signal-regulated kinases (ERKs) and Jun kinases (JNKs). Although the signaling cascade from growth factor receptors to ERKs is relatively well understood, the pathway leading to JNK activation is more obscure. Activation of JNK by epidermal growth factor (EGF) or nerve growth factor (NGF) was dependent on H-Ras activation, whereas JNK activation by tumor necrosis factor alpha (TNF-alpha) was Ras-independent. Ras activates two protein kinases, Raf-1 and MEK (MAPK, or ERK, kinase) kinase (MEKK). Raf-1 contributes directly to ERK activation but not to JNK activation, whereas MEKK participated in JNK activation but caused ERK activation only after overexpression. These results demonstrate the existence of two distinct Ras-dependent MAPK cascades--one initiated by Raf-1 leading to ERK activation, and the other initiated by MEKK leading to JNK activation. 相似文献
144.
Several applications for renewable energy conversion make use of variable speed generators. A conversion from variable frequency to grid frequency is therefore essential. One part of the converter is a rectifier. A rectifier model is presented, which is integrated in a time stepping finite element simulation environment where the generator and circuit equations are solved simultaneously. The model handles bidirectional alternator speeds as the application is a linear generator for ocean wave energy conversion. The rectifier model is extended with a load model, consisting of R, L and E, and simulations show what impact the rectifier has on the generator’s behaviour. 相似文献
145.
146.
Karin Ansttz 《International Journal of Communication Systems》1993,6(3):161-165
The introduction of ATM and broadband-based equipment into the European market requires considerable capital investment. It will result in a structural technological change, affecting the competitiveness of the European economy. Successful introduction depends on how both ATM network equipment and broadband based end-user equipment are brought onto the market. This paper focuses on economic benefits and anticipating marketing strategies, applicable in Europe with its specific, historically evolved structures. The price to pay for this ‘in-sight information’ is leaving out a global comparison. Refraining from evaluation whether conditions are good or bad for Europe or other areas, the article explains what conditions can be found there recently and where are the chances and challenges right now. 相似文献
147.
Waldemar Ternes Melanie Gronemeyer Karin Schwarz 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1995,201(6):544-547
p-Cymene-2,3-diol, carvacrol and thymol are components of thyme that exhibit antioxidant activities. The concentration of each substance was determined in different foodstuffs containing thyme extract. The stabilities ofp-cymene-2,3-diol, carvacrol and thymol were examined by heating lard containing thyme extract at temperatures from 80 °C to 160 °C. 相似文献
148.
John C Rothwell Karin Rosenkranz 《IEEE engineering in medicine and biology magazine》2005,24(1):40-44
In the healthy brain, there is a highly organized relationship between sensory input from one part of the body and the motor cortical output to muscles acting on that same part. This work investigates whether a change in purely sensory input have an impact on the organization of the motor cortex. In a previous study transcranial magnetic stimulation (TMS) techniques were used to probe the excitability of the motor cortex hand area. A measurement of the amplitude of the motor evoked potential (MEP) to standard single-pulse stimuli given through a focal coil was done. The excitability of two types of intracortical inhibition, SICI and LICI, was also measured using a paired-pulse TMS design. SICI is thought to be sensitive to activity in GABA/sub A/-ergic systems, whereas LICI may involve activation of GABA/sub B/-ergic systems. The work of other researchers has shown that these measures could be influenced by sensory input. Yet, all of them used electrical stimulation of peripheral nerve rather than a natural input. In order to investigate a more natural input, we delivered very low-amplitude vibration to the muscle belly of individual hand muscles through a small probe. This work explores the pattern of effects on MEPs and SICI in three different intrinsic hand muscles after vibration of each muscle in turn. In addition, the study also tested LICI with a paired-pulse TMS paradigm. In conclusion, it was seen that a period of sensory input, with or without the subject's attention, produces a specific pattern of sensory-motor reorganization in human cortex which develops quickly (after only 15 minutes) and lasts for at least 30 min. Since this produces changes in the motor cortex without requiring any active motor output, it may be a promising tool for neurorehabilitation even in patients who are unable to perform the active movements conventionally employed in therapy. 相似文献
149.
Five different types of cold protective footwear have been tested with regard to their resistance to dry heat loss (i.e. the insulation) with a new electrically heated foot model. The model is able to simulate ‘walking’ movements in order to provide a more realistic simulation of wear conditions. Thermal insulation of shoes with and without a steel toe cap was the same. The insulating properties during simulated walking movements were 10–25% lower compared with static conditions. For two of the shoe models a significantly lower insulation value for the sole area was obtained when adding a weight of 30 kg. A significant difference could also be found between the insulation values of two different sizes of one of the models. Measurements with the standard method (EN 344) correlated well with the local insulation value of the sole part of the thermal foot. Correlation with the insulation value for the whole shoe was much less, variation was bigger and ranking in terms of cold protection differed between methods. The electrically heated foot model appears to provide a reproducible, accurate and more realistic method for measuring the insulation properties of shoes than EN 344. 相似文献
150.
Karin E. Limburg Valerie A. Luzadis Molly Ramsey Kimberly L. Schulz Christine M. Mayer 《Journal of Great Lakes research》2010
Dreissenid (zebra and quagga) mussels are widely recognized as having strong, adverse ecological and economic impacts, e.g., biofouling and loss of water column primary production. We assessed perceptions and values associated with two less often considered ecological outcomes of dreissenid mussel influences on coastal ecosystems along Lake Ontario and the western St. Lawrence River in New York State. One, the generation of water clarity through filtration, we define as an ecosystem service; the other, the production of large amounts of nuisance algae (e.g., Cladophora and Microcystis) is defined as an ecosystem disservice. Surveys of business owners and homeowners quantified their preferences and the formation of values regarding these products of zebra mussel influence. Water clarity increased greatly, particularly in the eastern portion of Lake Ontario, and algal problems increased throughout. Businesses attributed increases and decreases in revenues associated with water clarity and algae; homeowners reported analogous changes in property values. Water clarity was positively associated, and algae negatively associated, with changes in revenues and property values. Threshold responses of costs as functions of filamentous algae were evident. Given the likely continued influx of invasive species due to human activities, further development of the ecosystem service concept should consider potential “goods” and “bads” of invasives and their influence on ecosystem and social system resiliency. 相似文献