Effect of between-category similarity on basic level superiority in pigeons

Children categorize stimuli at the basic level faster than at the superordinate level. We hypothesized that between-category similarity may affect this basic level superiority effect. Dissimilar categories may be easy to distinguish at the basic level but be difficult to group at the superordinate level, whereas similar categories may be easy to group at the superordinate level but be difficult to distinguish at the basic level. Consequently, similar basic level categories may produce a superordinate-before-basic learning trend, whereas dissimilar basic level categories may result in a basic-before-superordinate learning trend. We tested this hypothesis in pigeons by constructing superordinate level categories out of basic level categories with known similarity. In Experiment 1, we experimentally evaluated the between-category similarity of four basic level photographic categories using multiple fixed interval-extinction training (Astley and Wasserman, 1992). We used the resultant similarity matrices in Experiment 2 to construct two superordinate level categories from basic level categories with high between-category similarity (cars and persons; chairs and flowers). We then trained pigeons to concurrently classify those photographs into either the proper basic level category or the proper superordinate level category. Under these conditions, the pigeons learned the superordinate level discrimination faster than the basic level discrimination, confirming our hypothesis that basic level superiority is affected by between-category similarity.     

Students' cellular and molecular explanations of genetic phenomena

Genetic concepts are assigned to three principal levels of organisation: macroscopic level, microscopic level, and submicroscopic level. In order to probe Israeli students' understanding at each level, and to gain a sense of their ability to connect ideas and concepts across different levels, we asked three different types of question. Two of the question types ask students to make a bridge between levels by asking them to explain a phenomenon at one level using concepts and processes from a different level. For example, to explain the appearance of phenotypic traits (macroscopic level) using concepts like genes or chromosomes (microscopic level). One question dealt with the molecular level only. We investigated three populations: 9^th graders, 12^th graders, and pre-service teachers. Based on our findings we suggest improvements both in terms of teaching methods and curriculum content.     

东北地区绿色发展水平时空动态演变与障碍因素

以"人地协调"发展理念和"过程+格局+机制"思维范式为切入点,构建了基于DPSIR模型的绿色发展水平指标体系,运用熵权TOPSIS模型、障碍度模型和GIS空间可视化等方法对2008-2017年东北地区各城市的绿色发展水平时空分异特征与障碍因素进行实证研究。结果表明：①研究期内东北地区各城市绿色发展水平总体呈现从"小差距低水平"逐渐向"大差距高水平"转变的时序特征,空间分布大致呈现自北向南阶梯式递减的格局特征,且空间集聚效应显著。②东北地区各城市经济发展水平与绿色发展水平之间并非完全呈正相关关系,即,经济发展水平越高的城市,绿色发展水平不一定越高;而经济发展水平较低的城市,绿色发展反而达到较高的水平。这可能与区域资源环境承载力的大小有关。③东北地区各城市绿色发展水平时空分异的作用机制不尽相同,其中,资源禀赋条件、经济发展状况、政府投资规模在绿色发展水平的变化中起着重要的作用,同时也是导致东北地区绿色发展水平不同阶段呈现不同进化特征的主要原因。     

Morphological responses to different flooding regimes in Carex brevicuspis

Water regime can be described by the depth, duration, frequency, and timing and predictability of flooded and dry phases. Despite growing recognition of the importance of water regimes in the regulation of plant growth and distribution, which components of water regimes that determine plant growth are not well known. To identify the causative components, 72 ramets of Carex brevicuspis were grown under six different water regime treatments (treatment A: constant 0 cm water level; treatment B: constant 30 cm water level; treatment C: 0 cm water level to 30 cm water level for 30 days, repeated 2 times; treatment D: 30 cm water level to 0 cm water level for 30 days, repeated 2 times; treatment E: 0 cm water level to 30 cm water level for 5 days, repeated 12 times; and treatment F: 30 cm water level to 0 cm water level for 5 days, repeated 12 times). Biomass accumulation, below:above ground biomass ratio, number of ramets, and proportions of spreading and clumping ramet were assessed. Biomass accumulation decreased only in relation to length of flooding. The highest biomass accumulation occurred in the 120‐day + 0 cm water level treatment, it was intermediate in the four 60 day + 30 cm water level treatments, and lowest in the 120 day + 30 cm water level treatment. Likewise, the below:above ground ratio decreased only with increasing length of flooding. Ramet number was highest in the 120 day + 0 cm water level treatment, intermediate in the four 60 day + 30 cm water level treatments, and lowest in the 120 day + 30 cm water level treatment. The proportion of spreading ramets increased from 28.0% in the 120 day + 0 cm water level treatment to 76.4% in the 120 day + 30 cm water level treatment. These data suggest that the growth of C. brevicuspis was only limited by the duration of flooding. Reduction of the below:above ground ratio and change from phalanx to guerrilla growth form are effective strategies for C. brevicuspis to acclimate to flooding stress, because they allow the plant to grow above the water surface and escape from anoxic conditions. Our study provides experimental information on the role of different components of water regimes in regulating plant growth, and may assist in protection and restoration of the C. brevicuspis community.     

Cholinesterase Levels in Blood Plasma and Erythrocytes from Calves,Normal Delivering Cows and Cows Suffering from Parturient Paresis

Plasma cholinesterase (pChE) levels and erythrocyte acetylcholinesterase (eAChE) levels were studied in 6 cows before, during and after parturition (Group I), their calves (Group II), 38 cows suffering from parturient paresis (Group III) and 14 newly delivered non-paretic cows (Group IV). The mean of the pChE level in Group I was 1.5 μkat/1 ± 0.20 before parturition and decreased significantly (P ≦ 0.05) to 1.2 ukat/1 ± 0.16 after parturition. The eAChE level was before parturition ≅ 140 ukat/1 and decreased to ≅ 130 μkat/1 4–5 weeks after parturition. At birth the pChE level was 12.8 ukat/1 ± 5.9 in Group II. After 4 weeks the level had decreased to 2.3 ukat/1 ±0.3. In the bull calves the pChE level started to increase when they were 6 weeks old and reached a level of 5.7 μkat/1 ± 0.6 before slaughter at 6 months of age. The heifers did not show this increase. They had a level of around 2 μkat/1 throughout the investigation. The eAChE level at birth was 119 μkat/1 and increased slowly to a level of 145 μkat/1 at 6 months. No differences between the sexes were found. The cows suffering from parturient paresis had a pChE level of 1.80 μkat/1 ± 0.30 before treatment with calcium (Ca). The level decreased significantly (P ≦ 0.001) after Ca-infusion to a level of 1.67 ukat/1 ±0.29. Group IV had a pChE level of 1.65 μkat/1 ± 0.42 at parturition. Two to 4 months later the cows that had recovered from milk fever had a level of 1.61 μkat/1 ± 0.31 and the control cows 1.66 ukat/1 ± 0.48. No differences between the groups were found for the eAChE level. The findings show that parturition influences the pChE level in cows and that sex influences the pChE level in calves between 6 weeks to at least 6 months of age. Furthermore the elevated pChE level found in the cows suffering from parturient paresis before Ca infusion may be a further sign of a disturbance in the cholinergic system with a special preference to the neuromuscular junctions.     

The dynamics of neuron activity level in the striatum of the monkey brain in relation to the realization of multistage behavior

Level of the unit activity was studied in the monkey putamen during multistage behavior. Two groups of neuron activity patterns were distinguished. The first one involved patterns of low level neuron activity less exceeding the background level than the second one; the other group involved patterns of high level neuron activity exceeding the background level in the second time. These kinds of patterns were behavior-related. Patterns with low level neuron activity were recorded preferentially in relation to the trigger stimuli and reward. Patterns of high level neuron activity were recorded in relation to the decision-making, movements of arms in the left and right directions. Besides, their number rose in relation to the auditory cue reported to right realization of the task. It was established that the number of patterns of high level neuron activity rose in key moments of behavior, while the number of the patterns of low level neuron activity decreased.     

粘着斑激酶在TNF-α作用下影响SMMC-7721细胞PKB的表达水平

 探讨在肿瘤坏死因子α(TNF-α)作用下 ,粘着斑激酶 (focal adhesion kinase,FAK)对蛋白激酶 B(PKB)蛋白水平的影响 .利用构建、转染 FAK反义质粒来特异性降低 SMMC- 772 1细胞的FAK含量 ,及用 Western杂交的方法来检测 PKB的蛋白含量 .文献报道 TNF- α能够激活磷脂酰肌醇 3-激酶 (PI3K)而使 PKB发生磷酸化 .但是至于 TNF-α对 PKB蛋白水平的影响目前并无报道 .研究发现 ,当用 wortmannin特异性抑制 PI3K活性后可以显著降低 PKB的蛋白含量 .提示PI3K对维持 PKB的基础蛋白水平是必需的 .但是 TNF- α本身对 PKB的蛋白水平无明显影响 .而当用不同浓度的 TNF- α和 wortmannin处理 SMMC- 772 1细胞时 ,发现 PKB的蛋白含量随着TNF-α浓度的增加而降低 .提示 TNF-α可能除了通过 PI3K外 ,还可能通过另一条途径来下调PKB的表达 .而当用 FAK反义质粒转染 SMMC- 772 1细胞后 (FAK下降了 60 % ) ,发现在当用不同浓度的 TNF- α处理的情况下 ,FAK反义质粒转染株 AS- 772 1细胞的 PKB含量降低为对照的70 % ;而在用 TNF-α和 wortmannin处理的情况下 ,下降为对照的 40 %～ 60 % .TNF-α能够通过PI3K及另一未知途径来影响 PKB的蛋白水平 .而 FAK在 TNF- α作用下能够不通过 PI3K来影响PKB的蛋白水平 .     

Direct effect of glucose on the preproinsulin mRNA level in isolated pancreatic islets

The effects of glucose on the preproinsulin mRNA level and the rate of (pro)insulin biosynthesis were examined in isolated mouse pancreatic islets. Relative concentrations of preproinsulin mRNA were quantitated by a RNA-dot hybridization procedure. The level of preproinsulin mRNA in islets incubated for up to 7 days at 20 mM glucose remained constant. In islets incubated at 3.3 mM glucose the preproinsulin mRNA level decreased and was after 24 h reduced to one tenth of the level at 20 mM glucose. Subsequent incubation at 20 mM glucose completely restored the preproinsulin mRNA level but only after 3 days of culture, while the insulin release was restored within 24 h. The insulin-biosynthetic activity of the islets was correlated to the variation in the level of the preproinsulin mRNA. These results suggest that glucose does have a direct influence on the level of preproinsulin mRNA and that the rate of (pro)insulin biosynthesis is limited by the level of the preproinsulin mRNA.     

Bile acid and cholesterol excretion in the pregnant guinea pig: Studies on the hypercholesterolemia of pregnancy

The relationship of bile acid and cholesterol excretion to changes in plasma cholesterol during pregnancy were studied in guinea pigs. Plasma cholesterol level increased in the first trimester of pregnancy, reached to a peak during the second trimester and decreased in the third trimester reaching the lowest level at one week prior to parturition. Cholesterol level returned to the control level after parturition. Plasma triglyceride level followed a similar trend attaining peak values at second trimester and gradually returned to the control level at the third trimester of pregnancy. Bile acid and total sterol excretion were significantly higher in guinea pigs during the last phase of pregnancy while they remained unchanged during early stage of pregnancy.     

A Markov decision model for computer-aided instruction

A mathematical model for computer-aided instruction is developed. It is assumed that the course is divided into a hierarchy of levels of difficulty. These levels are such that if a student is able to perform successfully at a given level of difficulty, he can also perform successfully at all levels of lesser difficulty. Furthermore, if student performs successfully at one level, it increases his probability of being able to perform successfully at the next higher level of difficulty. Given the initial vector of probabilities for successful performance at each level, the vector describing how these probabilities change with successful performances at each level, and the expected times it takes to attempt a successful performance at each level, this model computes an instructional sequence that minimizes the expected time required for the student to complete the course by performing successfully at the highest level of difficulty. Dynamic programming is used to find this sequence.     

长三角地区城市生态旅游发展水平时空演变及其影响因素

城市生态旅游作为旅游可持续发展的一种理想模式,是对城市环境问题和旅游发展方式的一种回应。基于城市生态旅游核心要义,构建城市生态旅游发展水平评价指标体系,运用熵权TOPSIS法对2010-2019年长三角地区41个城市的城市生态旅游发展水平进行测度,通过标准差椭圆和马尔科夫链分析其时空演变特征,并利用地理探测器探析城市生态旅游发展的影响因素。结果表明:(1)长三角地区城市生态旅游各维度发展水平增速各异,供给和保障是影响综合发展水平的主要因素,各维度空间格局差异显著;(2)城市生态旅游综合发展水平呈波动上升态势,增速较缓;空间分布较不均衡,已初步形成"东南高-西北低"的分布格局;(3)城市生态旅游发展水平重心呈现"西北-东南-西北"的偏移规律,向东南部集聚程度逐渐增强,水平等级转移仅发生在相邻等级之间;(4)交通发展水平和城镇化水平对城市生态旅游发展的影响较为显著,经济发展水平和居民收入水平的影响逐渐增强,产业结构水平和环保重视程度的促进效果不显著;两因子的交互作用大于单因子的作用力,表现出双因子增强或非线性增强的交互关系。研究结果可为长三角地区提高城市生态旅游发展水平与全面推进旅游可持续发展提供一定的理论依据与科学参考。     

湖泊最低生态水位计算方法

研究湖泊最低生态水位的计算方法 ,对解决我国湖泊生态退化问题具有重要现实意义。针对我国湖泊生态资料缺乏的情况 ,提出 3种确定湖泊最低生态水位的方法。认为湖泊天然生态系统已经适应了天然多年最低水位 ,据此提出利用湖泊多年天然水位资料确定湖泊最低生态水位的方法——天然水位资料法 .认为要使湖泊生态系统不出现严重退化 ,必须使湖泊水文和地形子系统不严重退化 ,据此提出湖泊形态分析法 .从生物对生存空间的最小需求角度 ,以鱼类为指示生物 ,提出生物最小空间需求法。采用上述 3种方法计算了南四湖最低生态水位。计算结果表明 ,南四湖上级湖最低生态水位的范围为 32 .75～ 33.2 5 m,平均值为 33m;下级湖最低生态水位范围 31.2 5～ 31.75 m,平均值为 31.38m。上下两湖最小生态水位相应湖面面积之和为 5 93～86 0 km2 ,平均水位相应面积之和 70 8km2 ,占 195 3～ 1979年多年平均湖面面积 12 2 5 km2 的 5 8%。从保护南四湖自然保护区的角度看 ,确定的最低生态水位合理     

Benorylate in Management of Still's Disease

The present recommended dose of benorylate is not satisfactory for the management of children suffering from inflammatory polyarthritis. A starting dose of 200 mg/kg/day should be used, and the salicylate level checked at seven days and the dosage adjusted to give an anti-inflammatory effect—that is, a blood salicylate level of between 25 and 30 mg/100 ml. Once a satisfactory level has been achieved, this dosage should be maintained with occasional monitoring of the salicylate level. The paracetamol level does not need to be estimated as it tends to follow the salicylate level, provided that liver function is normal; thus it is quite safe to monitor only the salicylate level. Given in an adequate dosage, benorylate seems to be an acceptable salicylate preparation for use in juveniles suffering from chronic polyarthritis.     

Synthesis and degradation of nitrite reductase in pea leaves

We have shown in a previous publication (Gupta, Beevers 1983 J Exp Bot 34: 1455-1462) that the level of extractable nitrite reductase activity in pea (Pisum sativum cv Burpeeana) leaves is subject to environmental perturbations. In the current study, we have used rocket immunoelectrophoresis to quantitate the level of nitrite reductase protein in extracts from pea plants subjected to various environmental treatments. The level of nitrite reductase cross-reacting material closely followed the level of assayable nitrite reductase activity. The environmental conditions which enhanced the level of extractable nitrite reductase activity resulted in an increased level of nitrite reductase cross-reacting material in the extracts. In contrast, environmental conditions which resulted in a decrease in the level of extractable nitrite reductase activity produced a decline in cross-reacting material. These results indicate that the environmentally induced modulation of extractable nitrite reductase activity involves alteration of enzyme level and is not mediated by a reversible activation-inactivation of the existing enzyme.     

Dynamics of various integral characteristics of individual changes in ethanol resistance in isolated muscles of grass frog]

A study was made of the dynamics of the mean level of toxic ethyl alcohol (EA) (3.5 M) resistance, of the correlation between the initial individual level of this resistance and the value and shifting direction of the level, and of the pattern of correlation between levels of resistance in the pair sartoria muscles and variability of resistance level in muscles, kept in EA subtoxic solutions (0.87 and 1.09 M) for 240 min. Two-phase changes in the mean level of resistance in muscles were revealed that involved its increase by 20% within 60 min of maintenance in both EA concentrations, and followed by a decrease of this level by the end of observation. On the first steps of muscle maintenance in EA subtoxic solutions, a negative correlation was noticed between the initial level of resistance and the value and direction of its shifting, in addition to narrowing the range of variability of this level in muscles. All these events were accompanied by a decrease or fluctuations in the correlation coefficient between levels of resistance in the pair muscles. By the end of the experiment, the range of variability of the level of resistance was seen to increase, and the earlier negative correlation between the initial individual level of resistance and the value and direction of its shifting appeared to change for a positive one. Both processes preceded the decrease in the mean level of muscle resistance.     

Regulation of glycolysis during acclimation of scallops (Patinopecten yessoensis Jay) to anaerobiosis

Some glycolytic metabolites in the adductor muscle were measured after transfer of scallops from aerobic to anaerobic saltwater for 12 h. The level of octopine increased gradually during the initial 3 h incubation, and thereafter the level increased rapidly up to 12 h. The ATP level also did not show any significant change for the initial 3 h, and then decreased rapidly. The fructose 2,6-biphosphate (Fru 2,6-BP) level increased drastically during the initial 3 h incubation, but thereafter the level did not show any significant change up to 12 h. In the short-term effects of anaerobiosis for 90 min, the level of fructose 6-phosphate (Fru 6-P) increased just after transfer to anaerobiosis, and then its level decreased. In contrast, the fructose 1,6-biphosphate (Fru 1,6-BP) level increased greatly, at the time when both glucose 6-phosphate (Glc 6-P) and Fru 6-P decreased. The Fru 2,6-BP level did not any significant change during the initial 15 min incubation, but thereafter the level increased gradually up to 90 min. Scallop 6-phosphofructo 1-kinase (EC 2.7.1.11) (PFK1) was strongly activated by 1 microM Fru 2,6-BP when 0.2 mM Fru 6-P was used as a substrate, but the activity was not affected at 5 mM Fru 6-P. In view of these results, the regulation mechanism of glycolysis is discussed.     

Changes in relationship between blood glucose level and plasma 1,5-anhydroglucitol level in KK mice

We compared the relationship of the blood glucose level to the plasma 1,5-anhydroglucitol (1,5AG) level between KK mice with abnormal glucose metabolism and ICR mice as controls. Although the plasma 1,5AG level did not show any significant correlation with the blood glucose level in the controls, it tended to logarithmically decrease with the rise in the blood glucose level in KK mice. Thus it is possible that the plasma 1,5AG level is specifically related to the abnormal glucose metabolism in this model of diabetes mellitus and that its routine examination in diabetic patients may help delineate the metabolic derangement in the disease.     

Dynamics of plasma Ca and calcitonin levels in stonefish (Inimicus japonicus) administered a high-Ca solution into the stomach

In stonefish, changes in plasma total Ca and calcitonin levels were examined after administration of a high-Ca solution into the stomach. Blood was taken successively at 0, 1, 3, 9, 33, and 81 hr from a fine tube cannulated into the aortic bulb. Plasma Ca levels increased acutely at 1 hr and attained the peak after 3-9 hr of the administration. Although plasma calcitonin levels did not exhibit conspicuous changes for 1-3 hr, they began to rise significantly at 33 hr. The plasma Ca level began to decline significantly at 33 hr, although the level was still significantly higher than the initial level. At 33 hr, however, the plasma calcitonin level still continued to increase. At 81 hr, the plasma Ca level had returned to the initial level. At that time, the plasma calcitonin level was also significantly lower than that at 33 hr. These results suggest that, in stonefish, the ultimobranchial gland has the ability to respond physiologically to rises in plasma Ca levels, to secrete calcitonin, and to cease the secretion when the plasma Ca levels return to the initial level.     

EEG frequency: amplitude characteristics at different levels of consciousness

Relationship was studied between the level of consciousness and the level of the brain activation. State of transition from wakefulness to drowsiness was used as a model of gradual decrease in the level of consciousness. A change in the intensity and quality of appearing involuntarily mental processes served as an index of the level of consciousness as determined by subjects' self-reports. It was found that a certain EEG profile corresponded to each level of consciousness under study. The data obtained showed that the lowest level of activation corresponded to a state in which a subject develops inhibition of "internal speech", "failure of thoughts". In this case, the dynamics of the EEG high frequency rhythm changes was possibly related to the mechanism of transmission of cognitive information.     

p300乙酰化在卡介苗感染中的作用

研究p300乙酰化在卡介苗(bacillus Calmette Guérin,BCG)感染中的作用。构建THP-1巨噬细胞模型,比较BCG感染前后p300蛋白表达水平和组蛋白H3乙酰化水平的改变,加入p300特异性抑制剂Delphinidin,观察细胞内组蛋白H3乙酰化水平的变化。结果表明,在分化成熟的THP-1细胞系中,BCG感染能够上调p300蛋白表达水平和组蛋白H3乙酰化水平,加入p300特异性抑制剂Delphinidin后,组蛋白H3乙酰化水平降低。BCG感染通过p300途径导致蛋白质乙酰化水平发生改变。