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1.
In this study, 30 subjects were exposed to different combinations of air temperature (Ta: 24, 27, and 30°C) and CO2 level (8000, 10 000, and 12 000 ppm) in a high-humidity (RH: 85%) underground climate chamber. Subjective assessments, physiological responses, and cognitive performance were investigated. The results showed that as compared with exposure to Ta = 24°C, exposure to 30°C at all CO2 levels caused subjects to feel uncomfortably warm and experience stronger odor intensity, while increased mental effort and greater intensity of acute health symptoms were reported. However, no significant effects of Ta on task performance or physiological responses were found. This indicated that subjects had to exert more effort to maintain their performance in an uncomfortably warm environment. Increasing CO2 from 8000 to 12 000 ppm at all Ta caused subjects to report higher rates of headache, fatigue, agitation, and feeling depressed, although the results were statistically significant only at 24 and 27°C. The text typing performance and systolic blood pressure (SBP) decreased significantly at this exposure, whereas diastolic blood pressure (DBP) and thermal discomfort increased significantly. These effects suggest higher arousal/stress. No significant interaction effect of Ta and CO2 concentration on human responses was identified. 相似文献
2.
Yingli Li Shaoying Zhang Yu Dong 《International Journal of Food Science & Technology》2021,56(1):115-125
Ethylene continues to be a major factor influencing quality of European pears during storage. Although research has been done on the effect of pre-harvest 1-methylcyclopropene (1-MCP) on physiological characteristics in pears, a full understanding of cultivar response and antioxidant metabolism remains elusive. Spraying 1-MCP on ‘Bartlett’ and ‘d’Anjou’ pears was studied with respect to physiology, storage and eating quality, disorders, and antioxidant properties at two harvest date (H1 and H2) during storage and ripening. Treatment with 1-MCP extended the harvest window of ‘Bartlett’ and ‘d’Anjou’ pears 3 and 4 days, respectively, without reducing storage or eating quality. Treatment with 1-MCP reduced ethylene production (EPR) and respiration rates (RR), maintained fruit firmness and green colour during storage and retarded development of desirable melting texture in both cultivars. Additionally, 1-MCP lowered the incidence of disorders by alleviating membrane lipid peroxidation, retaining high total flavonoids (TF) and antioxidant capacity, and enhancing superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in both cultivars. Overall, pre-harvest 1-MCP applications could extend storage time of ‘Bartlett’ and ‘d’Anjou’ pears to 5 and 6 months, respectively, at −1.1 ± 0.5 °C, by reducing ethylene synthesis and enhancing antioxidant metabolism. 相似文献
3.
应用Nd:YAG激光(波长1.06μm,功率5w,照射时间0.5-3 min)和Ar+激光(波长488nm,功率70mw,照射时间5-15min)对长期保存的不同保存形式的塔胞藻(Pyramidomonassp.)进行辐照处理。研究了不同剂量激光辐照对藻体生长和叶绿素含量的影响。实验结果表明:照射剂量为60s的Nd:YAG激光及剂量为15min的Ar+激光对液体保存形式的藻种有较明显的促长效果,接种后这两种激光处理组的比生长速率分别较对照提高达53.33%和28.89%,叶绿素含量分别增加73.33%和65.69%。两种激光对液体保存藻种的活化效果均好于固体保存种。 相似文献
4.
5.
相干源二维波达方向估计 总被引:4,自引:0,他引:4
本文分析了平面阵接收信号的协方差矩阵,发现它可分解为一个广义对称矩阵与一个非广义对称矩阵之和,利用信号协方差矩阵的这一结构特征,重点研究了相干源二维波达方向(DOA)估计.该方法通过构造一个差矩阵,求出其本特征值对应的任一特征向量,利用谱函数估计相干源二维DOA.简要分析了二维DOA估计的分维处理。 相似文献
6.
Guangyan Li W. Ian Hamilton Ged Morrisroe Theresa Clarke 《Cognition, Technology & Work》2006,8(1):30-40
A study was carried out using simulation to investigate driver responses to lineside signals and signs at various approach
speeds. The objectives of the study were: (1) to find out whether train speed would significantly affect signal/sign reading;
(2) to examine at which point certain types of signs or signals could be detected or recognised, and (3) to determine a speed
cut-off level above which certain types of signs or signals are no longer recognisable or detectable. Fifty-seven train drivers
from 12 Train Operating Companies in the UK participated in the trials. Twenty different types of lineside signs and ten types
of signals were tested under six different approach speeds ranging from 100 to 350 km/h (62–218 mph). Driver performance measures
were ‘time remaining to the signal/sign’ at the point of detection or recognition, and reading error rate. The results showed
a significant influence of train speed on driver responses to lineside signals/signs and demonstrated a non-linear relationship
between driver responses to signals/signs and approach speed. This has been used to estimate a maximum approach speed limit
within which a specific signal or sign can be correctly detected or recognised. The findings and implications of the study
are discussed in the paper. 相似文献
7.
大蒜活性成分阿霍烯的研究概况 总被引:2,自引:0,他引:2
阿霍烯作为源自于大蒜的一种活性成分,较之蒜素更加稳定且不具有令人难以接受的蒜辣蒜臭气味,具有抗血栓形成,诱导肿瘤细胞调亡及抗菌消炎等特别的生理功效,是一种天然高效的活性成分。本文综述了近年来有关阿霍烯的生理功效,结构组成及形成机制等的研究概况。 相似文献
8.
Cunningham William A.; Johnson Marcia K.; Gatenby J. Chris; Gore John C.; Banaji Mahzarin R. 《Canadian Metallurgical Quarterly》2003,85(4):639
Evaluative responses appear to involve 2 seemingly distinct sets of processes: those that are automatically activated and others that are more consciously controlled. Using functional magnetic resonance imaging, the authors investigated the brain systems associated with automatic and controlled evaluative processing. Participants made either evaluative (good-bad) or nonevaluative (past-present) judgments about famous names. Greater amygdala activity was observed for names rated as "bad" relative to those rated as "good," regardless of whether the task directly involved an evaluative judgment (good-bad) or not (past-present). Good-bad judgments resulted in greater medial and ventrolateral prefrontal cortex (PFC) activity than past-present judgments. Furthermore, there was greater ventrolateral PFC activity in good-bad judgments marked by greater ambivalence. Together, these findings indicate a neural distinction between processes engaged for automatic and controlled evaluation. Whereas automatic processes are sensitive to simple valence, controlled processes are sensitive to attitudinal complexity. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
According to J. F. Dovidio and S. L. Gaertner's (1998) integrated model of racism, politically liberal European Americans tend to express racism differently than conservative European Americans, with liberals demonstrating aversive racism and conservatives, symbolic or modern racism. In support of the model, in Experiment 1 liberals showed bias in favor of a twice-prosecuted African American relative to a European American in their judgment of double jeopardy, whereas conservatives did the reverse. Experiment 2 replicated these effects while eliminating a confound in the design of Experiment 1. Experiment 3 found evidence for the intrapsychic conflict hypothesized to underlie aversive racism. Specifically, only liberals displayed greater physiological arousal to the touch of an African American versus a European American experimenter. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
10.
June E. Rickard 《Journal of the science of food and agriculture》1985,36(3):167-176
Rapid post-harvest physiological deterioration of cassava roots (Manihot esculenta Crantz) appears to be due essentially to wound responses, comparable to those observed in other plant storage organs. The wound responses observed include: increased activity of phenylalanine ammonia lyase, an enzyme associated with phenol biosynthesis; increased activity of peroxidase and polyphenol oxidase; formation of phenols/polyphenols including leucoanthocyanidins, catechins, sco-poletin and condensed tannins, and often the formation of a wound periderm. In cassava, the responses did not remain localised at wound surfaces in roots when held at low storage humidity but spread through the roots causing a discolouration of the vascular tissue and storage parenchyma. Roots stored at high humidity showed a more typical wound response with localised production of phenols and periderm formation. 相似文献