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1.
Two-spotted spider mites (Tetranychus urticae Koch) placed upon leaves treated with checkerboard-like discontinuous residues of 100 ppm dicofol were observed at time 0,3 h, 6 h and 24 h after application (h0,h3,h6 andh24, respectively). In one experiment, the mites were allowed to reside undisturbed upon a single leaf for the duration of the observations. In a second experiment, mites of one group were transferred to another webbing-free leaf with discontinuous dicofol residue for each observation period, while those of a control group were lifted off the leaf surface and returned to it (on the same leaf) prior to each observation period. The mites in all three groups eventually began to avoid the dicofol-treated squares during their nonlocomotory activities, in no instance was dicofolavoidance displayed by moving mites. Mites that lomained undisturbed upon leaves treated with discontinuous residue began to avoid the dicofol-treated squares byh3. The mites lifted above their leaf and replaced on it prior to each observation period did not begin to avoid the dicofol-treated squares untilh6. The mites transferred to a webbing-free leaf prior to each observation period did not begin to avoid the dicofol-treated squares untilh24. Attributes of tetranychid webbing, that may cause the last-mentioned group of mites to expend considerable energy in searching for a webbed area of leaf surface, are discussed.  相似文献   

2.
Abstract

Aim of the study: To investigate a more available model for the early phase of motor learning after action observation combined with motor imagery training in elderly people. To address the purpose, we focused on a slow, unskilled model demonstrating an occasional error.

Materials and methods: A total of 36 elderly people participated in the current study and were assigned to either the unskilled or skilled model observation groups (n?=?12, respectively), or the control group (n?=?12). The participants in the observation groups observed the assigned a video clip of an unskilled or skilled model demonstrating a ball rotation task. During the observation, the participants were instructed to imagine themselves as the person in the video clip. The participants in the control group read a scientific paper during the equivalent period of action observation and motor imagery. We measured ball rotation performance (the time required for five rotations, the number of ball drops) in pre- and post-intervention (observation combined with motor imagery training for intervention groups or reading for control group).

Results: Ball rotation performance (ball rotation speed) significantly improved in the unskilled model observation group compared to the other two groups.

Conclusions: Intervention for action observation using unskilled model combined with motor imagery was effective for improving motor performance during the early phase of motor learning.  相似文献   

3.
Objectives: The accuracy of cone-beam technique, cone-beam computed tomography (CBCT), compared with that of the multislice spiral CT (MSCT), for image-based linear measurements of midpalatal suture was assessed.

Material and Methods: Two measurements were performed by one investigator on the dry skull by using one digital caliper and in the axial cuts by using software. A 2D object-based image registration process was applied to determine the best affine transformation that maps a 2D input image (CBCT) in a reference image (MSCT).

Results: The value of the intraclass correlation coefficient was approximately 0.9%. The results suggest that differences between two scanners did not exist (observation 1, p = 0.964 and observation 2, p = 0.795). With regard to the dry skull and the image, the significance probabilities equaled zero (observation 1, p = 0.002 and observation 2, p = 0.004), therefore, indicating significant differences.

Conclusion: Measurements acquired in the images were similar and these findings contribute to stimulate the use of CBCT for evaluation of the maxillary expansion procedure.  相似文献   

4.
One observation in a mycorrhizal check-list that Buddleja davidii is nonmycorrhizal has been perpetuated in subsequent citations and used in a number of analyses of mycorrhizal ecology and evolution. Direct observation of B. davidii from New Zealand and the UK shows extensive arbuscular mycorrhizal fungal structures inside B. davidii roots. The suggestion that B. davidii is nonmycorrhizal is therefore not supported. The use of mycorrhizal checklists for analysis of plant traits and evolution needs to be undertaken with care to ensure the validity of underlying data.  相似文献   

5.
Pollination biology studies of the endangered herbal medicines Dendrobium chrysotoxum were conducted in natural pollination conditions using flower observation, pollinator observation and artificial pollination experiments. Populations of D. chrysotoxum with fragrance and nectar were pollinated by Ctenoplectra davidi Valhalla (Hymenoptera: Apidae) species. The floral structure of D. chrysotoxum adapted precisely to its pollinators. Flowers had a low capsule setting (0.17%) under natural conditions. However, compared to open pollination, artificial pollination experiments showed a significant increase in capsule setting, and D. chrysotoxum was cross-compatible and self-compatible, but there was pollinator limitation also. This study will provide important information for the preservation of this endangered species.  相似文献   

6.
通过标本观察,发现描述自我国河北迁西县的毛茛科乌头属植物迁西乌头(Aconitum qianxiense W.T.Wang)与华北和东北地区常见的北乌头(A.kusnezoffii Reichb.)没有本质区别,故将前者处理为后者的异名。  相似文献   

7.
目的:探讨抗幽门螺杆菌(HP)治疗对急性冠脉综合征(ACS)合并HP感染患者炎性标记物及再发心肌缺血事件的影响。方法:选取2016年10月到2018年10月期间我院收治的ACS患者90例,随机分为对照组(n=45,常规治疗)和观察组(n=45,常规治疗+抗HP治疗)。观察两组患者的临床疗效,比较HP根除率、血清炎性标记物[C反应蛋白(CRP)、白细胞介素-6(IL-6)、可溶性细胞间粘附分子-1(sICAM-1)]水平,记录再发心肌缺血事件和不良反应发生情况。结果:观察组的总有效率和HP根除率均高于对照组(P0.05)。两组患者经治疗后血清CRP、IL-6、sICAM-1水平均较治疗前有所改善(P0.05),且观察组的改善效果优于对照组(P0.05)。观察组患者再发心肌缺血事件的总发生率低于对照组(P0.05)。两组患者的不良反应发生率比较无明显差异(P0.05)。结论:ACS合并HP感染患者采取抗HP治疗可更好地缓解患者体内的炎症反应,降低再发心肌缺血事件发生率的同时还不会增加不良反应发生风险。  相似文献   

8.
谭深  王焓 《生态学报》2022,42(4):1487-1499
陆地生态系统碳、水通量估算是地球系统科学研究的基础和重要内容之一。当前部分碳、水通量模型在外推的过程中受到参数化结构和特征参数的限制,难以提升应用范围和结果精度。以生态水文最优性原理为理论工具,将基于该原理构建的C3植物普适性生产力模型P model推广至C4植物;在此基础上结合植物气孔行为的环境响应规律和水碳耦合原理,发展具有普适性的碳水通量耦合估算方法,协同计算我国总初级生产力(GPP, Gross Primary Production)和蒸散(ET, Evapotranspiration)。基于ChinaFLUX数据集的站点尺度验证结果表明,基于P model发展的的GPP和ET普适性估算方法精度表现良好:GPP估算结果与地面观测相比,相关系数R~2=0.61,均方根误差RMSE=2.1gC/d,拟合斜率0.96;ET估算结果相关系数R~2=0.66,RMSE=0.85mm/d,拟合斜率1.04。基于Google Earth Engine云平台实现了全国尺度GPP和ET计算,模拟结果与遥感太阳诱导叶绿素荧光观测、同类ET产品相比具有合理的空间分布,表明基于最优性原理构建的普适性碳...  相似文献   

9.
A new microscope produced by the company Lambda Praha, applicable to field studies, was used for the observation of biofilms growing on stones and rocks of the Red Sea beach at Sharm El Sheikh resort in Egypt. The microscope was equipped with a novel LED illumination system, independent of sunlight as the light source, and an attachable mechanical stage making possible a precise and systematic observation of the preparation. Using this device, black biofilms of cyanobacteria and green biofilms of algae were studied; characteristic sheaths protecting the cells against the intense sunlight were found in cyanobacteria belonging to the genus Lyngbya. Trichomes on phylloids consisting of 3 to 4 cells were observed in algae belonging to the genus Padina, whose nuclei were degraded as a result of apoptosis, which is in contrast to the species Padina pavonia containing visible nuclear residues observed on the shore of the Mediterranean Sea near Lastovo island in Croatia in 2007.  相似文献   

10.
《Science activities》2012,49(2):63-73
Abstract

This study aimed to support the development of the scientific observation skills of children at an early age using a pattern selected from nearby nature. For this purpose, a simple, innovative and authentic observation activity was designed using thorny burnet (Sarcopoterium spinosum L.), a plant unique to the Mediterranean region. The activity was conducted in a preschool institution with six-year-old children in the class hours of a weekly science course in three different environments (in-class, out-of-class, and out-of-school), and seven stages. In this activity, which aimed to transform children’s natural/spontaneous observation skills into scientific observation skills, patterns were revealed through systematic and sequential observation and drawings. At the end of the activity, it was found that the children had developed skills related to breaking a whole into its parts and putting the parts together according to patterns, making detailed observations, and systematic data collection, and they successfully implemented these skills outside the classroom and school.  相似文献   

11.
Experimental researches in Oltrepò Pavese (Padana Valley), on wheat rust epidemiological aspects related to the climatic conditions Our experimental researches began in 1976 in Oltrepò Pavese, one of the most important seedwheat growing environment in the Padana Valley. Wheat rust epidemiology, on the cv San Pastore, was studied in relation to the following climatic conditions: temperature and rain. Therefore, after having illustrated the modalities of observation and survey of the three rusts, we studied the infection behaviour on plants in field and hence the infection behaviour on the single leaves. In the end, knowing, by statistical analysis, the relations between infections and climatic parameters, it was possible to define as follows. By comparing the three rusts infections in our environment, we noted that San Pastore wheat has been more affected by Puccinia striiformis West. with maximum infection points of 26,4 % on the leaves. We noted the greater development of this infection from the fourth to the sixth observation, in correspondence with average values of T° max rising from 23,7° to 26,4°C; in the same period, precipitations varied with a daily average from 3,0 to 1,7 mm. Both P. striiformis and P. recondita Rob. ex Desm. appeared when the average of the T° max was 20,6°C, and in lack of rain. P. recondita had a development rising from the fourth to the sixth observation showing, with regard to P. striiformis, lower demands of humidity and relatively greater demands of temperature; in fact, it reached a maximum point of infection of 26,4 % on the leaves, assuming a more gradual development than P. striiformis. P. graminis Pers. appeared much later, as it needs higher T° max, followed by rains. Indeed, it appeared with average T° max of 23, 8 °C and with average daily rains of 0,4 mm, rising above all at the sixth observation with 26,4° C and 1,7 mm, respectively. So, we can affirm that the actual experimental investigations point out and confirm what has been already met by other Authors, that is: a) among the three rusts considered, P. striiformis and P. recondita show to begin their development at the same time, in climatic conditions characterized by T° max relatively mild and high environmental humidity; b) P. striiformis shows, afterwards, the highest infections percentages; c) P. graminis appeared much later reaching modest infection percentages.  相似文献   

12.
A mathematical model for the aerobic growth of Saccharomyces cerevisiae in both batch and continuous culture is described. It was based on the experimental observation that the respiratory capacity of organism may become saturated and exhibit a maximum specific oxygen uptake rate after suitable adaptation. This experimental observation led to the possibility that transport into and out of the mitochondrion was of major importance in the overall metabolism of S. cerevisiae and was subject to long-term adaptation. Consistent with this observation a distributed model was proposed which. as its basis, assumed the control of repression or inhibition of the uptake rates of other substrates. No other regulation of fermentation and respiration was assumed. The model provided a suitable structure allowing precise quantification of the changes in rate and stoichiometry of energy production. The model clearly indicated that growth under the wide range of experimental conditions reported could not be predicted using constant values for the maximum specific respiratory rate of constant values of YATP (g biomass/mol ATP) and PO ratio of (mol ATP/atom oxygen). The causes of the variation in the respiratory rate were not determined and it was concluded that a more detailed analysis (reported subsequently) was required. The variation of YATP and PO ratio with specific growth rate implied that the efficiency of ATP generation or ATP utilization decreased with increasing specific growth rate. It was concluded that it was not possible to quantify the individual effect of YATP and PO ratio until independent means for their reliable estimation is available.  相似文献   

13.
Summary A new pulse sequence is presented allowing the use of long selective pulses at the water frequency using standard equipment. Radiation damping is suppressed during the pulse by the use of gradient echoes programmed between the single pulses of a DANTE train. This WANTED (water-selective DANTE using gradients) sequence thus allows the observation of interactions with water without the use of special probe heads or filtering of undesired resonances. By combining the WANTED sequence with NOESY, ROESY and NOESY-GSQC experiments, we obtain selective 1D and 2D spectra fit to the observation of chemical exchange and dipolar interactions between water and protein protons.  相似文献   

14.
    
Summary Controlled feeding experiments were carried out with Microcystis aeruginosa to study its effect on the fingerlings of Labeo rohita. The observation reveals an overall improvement in the general condition and a marked increase in weight, volume and size of fishes as compared to control.  相似文献   

15.
Short-term temporal dynamics in a tidepool fish community were quantitatively examined through a series of direct observation at consecutive low tides in a temperate-subtropical intertidal of southwestern Japan. The visual observation was sufficiently effective compared with the capture by anaesthetics and allowed a continual, undisturbed monitoring. Species composition markedly varied between consecutive day versus night in spring-autumn, but not in winter. In contrast, species composition on consecutive days and on consecutive nights was relatively stable all through the year. The pattern of diel change in abundance varied among species and seasons. C. gulosus, Istiblennius sp. and Girella spp. showed the tendency of night-time occurrence, while B. fuscus individuals tended to occur by day. These trends of day–night differences were mainly observed in spring and summer and rarely in winter. Size differences between day and night were detected in B. fuscus, C. gulosus, Istiblennius sp. and Girella spp. This tidepool fish community demonstrated variation in abundance and body size on short time scales, which may be attributable to behavioural differences among species.  相似文献   

16.
The model considered is a two-factor cross-classification variance components model with one observation per cell. Let the two factors be A and B, the problem is to obtain an approximate confidence interval for the ratio of variance component A over variance component B. In this paper, a method of solving this problem is established and simulations are performed to check the method.  相似文献   

17.
为研究格木(Erythrophleum fordii Oliv.)的传粉方式和交配系统,在鼎湖山国家级自然保护区对珍稀濒危树种格木进行野外观察,花的微器官(花粉和柱头)用扫描电镜观察,并进行控制授粉实验和遗传分析。结果表明,格木具有颜色亮丽和散发香味的总状花序,格木花粉包被厚重的粘性物质,柱头没有易于捕获花粉的结构,风媒传粉没有坐果,推断格木应该是通过虫媒传播花粉,或者主要是通过虫媒传播。遗传分析和在不同繁殖环境的两棵目标树的坐果情况表明,格木偶尔可以自交产生后代,但异交占据着绝对的优势,鼎湖山格木种群的异交率达到90.6%。格木传粉方式和交配系统的研究有利于对格木进行保护和保育。  相似文献   

18.
Numerous previous studies have shown that one-zero sampling in direct observation systematically overestimates behavioral durations. Apost hoc correction procedure has been proposed and demonstrated to be capable of removing most of the systematic errors found in one-zero duration estimates. However, the remaining errors for some individual observation sessions can still be quite substantial in practical terms. In this paper, the condition under which thepost hoc correction procedure will produce results with negligible systematic errors in one-zero duration estimates is identified.  相似文献   

19.
Drosophila ananassae, a cosmopolitan and domestic species, is largely circumtropical in distribution and belongs to the ananassae species complex of the ananassae subgroup of the melanogaster species group. In the present study, experiments were conducted to investigate the effect of density on female remating frequency by employing different wild-type and mutant strains of D. ananassae. Two experimental designs, i.e., 2-h daily observation and continuous confinement, were used. The results show that there is significant dependence of remating frequency on density in all strains tested under both experimental designs except in a wild-type strain (Bhutan), which shows no dependence of remating frequency on density under 2-h daily observation design. This finding provides evidence that density may increase the frequency of female remating in D. ananassae.  相似文献   

20.
Shimizu Y  Urabe J 《Oecologia》2008,155(1):21-31
Initial theories of ecological stoichiometry were based on the assumption that the mass-specific content of key nutrient elements (such as P), changes little within a consumer species. However, evidence has shown that this content changes substantially according to feeding conditions. To clarify how the specific P content (S P) of a consumer species depends on food conditions and relates to the growth rate, we constructed a multiple mass-balance model incorporating feeding and metabolic costs and stoichiometrically regulated releases for C and P. The validity of the model was then tested experimentally by examining the growth rates and S P of Daphnia pulicaria under various food conditions. The experimental observation agreed qualitatively well with the model, showing that the S P of consumers relates positively to growth rate at high food C:P ratios but negatively at low food C:P ratios. Thus, within a consumer species, individuals with high S P do not necessarily grow at high rates. The concordance in results between the model and our observation suggests that maintenance costs for both P and C are substantial regardless of food conditions and play crucial roles in determining the relationship between the S P and growth rate of consumers.  相似文献   

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