Subjects: Psychology >> Cognitive Psychology submitted time 2023-11-06
Abstract： Visual working memory (VWM) plays a foundational role in advanced cognitive functions. The state-based models propose a hierarchical organization of functional states, where memory representations with high attentional priority are retained in an online state (i.e., active state), while those with lower priority are kept in an offline state (i.e., passive state) for later use. The memory representations can be dynamically transferred between the two states according to the task demands. However, there was rare work to explore how the memory representations transitioned into the offline state from the online, generating the offline representations. Here, we put forward two hypothesis, the consolidation hypothesis and the fade-away hypothesis.
To explore this question, participants were instructed to remember two sequential memory arrays, with Memory array 2 being detected before Memory array 1. In this memory task, Memory array 1 was held in the offline state during the active maintenance of Memory array 2. Colored squares served as memory stimuli. 30 healthy college students participated in each experiment. We primarily modulated the temporal context related to the state transformation of memory representations: the interval delay between the two memory arrays in Experiment 1 and the presentation time of Memory array 2 in Experiment 2. The load of online memory varied between two and four in each trial. These variables were within-subject factors. Experiment 1 aimed to verify that the shortage of interval delay between memory arrays led to the failure of state transformation in the condition of 0.8s-interval. Experiment 2 attempted to determine which hypothesis, consolidation or fade-away, aligned better with the state transformation process.
The exploration of representational state transformation was built on the resources-dissociation account, which proposed that the offline representations are independent of the active processing of online representations. Memory arrays 1 and 2 were used to test the offline and online memory, respectively. The results of Experiment 1 showed that variations in online load did not affect offline memory when extending the interval delay from 0.8s to 1s. This indicated that the state transformation of Memory array 1 continued beyond 0.8s after its disappearance and could complete within a 1s-interval. In Experiment 2, the interval was designed at 0.8s. We observed that the online load variation had no impact on offline memory when extending the presentation time of Memory array 2 from 0.2s to 0.5s. This supported the consolidation hypothesis, indicating that the sufficient presentation time of Memory array 2 allowed for the state transformation of Memory array 1 to complete before the subsequent processing of Memory array 2. Thus, we concluded that the state transformation involved a consolidation processing to transfer the online representations to the offline state, rather than natural fade-away of persistent neural activity.
In summary, the state transformation acts as a process of consolidating online memory representations into the offline state, thereby forming offline representations. This process can be completed within a sufficiently long retention interval, or continue during the presentation of subsequent stimuli when providing a deficient interval. The current findings provide fresh insights into the mechanisms of representational maintenance in the two distinct states.
Subjects: Biology >> Botany >> Applied botany submitted time 2023-10-22 Cooperative journals: 《广西植物》
Abstract： In order to investigate a new way to replace the exotic mangrove Laguncularia racemosa plantations gradually with native mangrove forests through thinning and pruning without drastic habitat disturbance in the reserve, this study took the exotic mangrove L. racemosa forests introduced in Hainan Dongzhai Harbor National Nature Reserve as the study area, and L. racemosa forests were thinning and pruning relying on the reserve. The purpose was to study the ecological effects of the thinning and pruning of L. racemosa forests on the restoration of native mangrove communities. The results show that: (1) Asexual reproduction of L. racemosa stump sprouting after thinning and pruning weakened the treatment effect, and there was no significant difference in the effect of L. racemosa stump sprouting between one intervention (50% intensity of thinning and pruning) and two interventions (50% intensity of thinning and pruning followed by an additional pruning). (2) Both intervention methods enriched native mangrove species and promoted their growth in the understory shrub layer, and the two interventions had a more significant promotion effect than the one intervention. However, there is no significant effect on the natural regeneration of mangrove seedlings in the herbaceous layer. (3) In the experiment of planting native mangrove seedlings in the three plots of non-thinning, thinning, and forest margin, the survival rates of Rhizophora stylosa and Kandelia obovata seedlings were promoted by the thinning and pruning measures. The effect of thinning and pruning treatment on the growth of R. stylosa seedlings was close to the forest margin conditions, but the effect was limited. Therefore, we suggest increasing the thinning intensity or pruning frequency based on 50% intensity thinning and pruning, carrying out artificial planting of native mangrove plants in the understory appropriately, and removing the sprouting branches from the stumps of L. racemosa, which is more conducive to the conversion of L. racemosa plantation to native mangrove community.
Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： Attentional selection does not only exist in the visual processing, but also points to a number of short-stored memory representations. At the behavioral level, both types of attentional mechanisms exert a facilitatory effect on the task performance. Besides, this facilitatory effect is stable across different patterns of attentional distribution. At the neural level, on the one hand, due to the fact that the encoding and short-term storage of the visual information are mainly processed in the occipital region (V1~V4) topologically related to retina, these regions can thus serve as a valid platform for the operation of the two types of attentional selection; on the other hand, the controlling signal from dorsal fronto-parietal network could modulate the selective attention processing in the visual cortex in a top-down manner, which consequently facilitates the priority of the target processing. These new evidence indicating that both types of attentional selection may arise from a unified control mechanism. At the same time, the neural frameworks described in this article also provide a new perspective for re-understanding of the relationship between attention and visual working memory.
Subjects: Psychology >> Developmental Psychology submitted time 2023-03-28 Cooperative journals: 《心理科学进展》
Abstract： In the process of visual working memory, the maintenance and manipulation of the memory items require transforming a fleeting sensory input into a durable working memory representation, which is defined as the visual working memory consolidation. In light of the “gating” role of the consolidation, the researchers have developed a variety of research paradigms to explore the mechanisms that may be involved. However, the time course and the patterns of consolidation observed under different paradigms is quite different. Moreover, there are also different views on the theoretical and neural mechanism involved in consolidation. By comparing the differences among different paradigms and sorting out the views of various parties, the solutions to these problems can be effectively promoted. In addition to verifying the consolidation model in a variety of paradigms, future researches can also explore the role of attention in consolidation and how factors such as project familiarity affect consolidation processing.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Although visual working memory (VWM) has been studied for decades, the storage mechanism of VWM remains unclear. A strong object-based theory and a weak object-based theory have been proposed for the VWM storage mechanism. The arguments of these two theories focus on whether features from the same dimension can be integrated into the representation of objects stored in VWM. The strong object-based theory claimed that object was a unit of VWM, the capacity of which was not affected by the number of features. However, the recent studies have proved that weak object-based theory because the features from the same dimension (e.g., two colors) cannot be integrated simultaneously into the representation of objects in VWM, and the VWM capacity was constrained by the number of features. The aim of this paper is to explore whether features from the same dimension can be successfully integrated into a representation of objects stored in VWM. Based on the finding of previous study, we proposed that experimental paradigm and stimulus property might be the main factors that influence the integration of same-dimension information into a representation. Two experiments were conducted to test whether these two factors could affect the integration process respectively. Experiment 1 used a recall task to investigate whether experimental paradigm is a main factor to influence the integration of same-dimension features. The results show that, no matter which experimental paradigms, participants were unable to integrated the same-dimension features into a representation. These suggests that experimental paradigm is not a main factor for explaining the failure of the integration of same-dimension features into a representation stored in VWM. Experiment 2 was conducted to explore whether stimulus property could affect the integration of same-dimension features. Two types of stimulus were selected as experimental materials (e.g., meaningless and meaningful objects). We expected that, in meaningful object condition, participants would easily memorize two conjoint colors as one representation because of the integrated clues (the meaningful shapes); in contrast, participants were more likely to memorize the two features separately due to the absence of integrated clues. The results of Experiment 2 show that, the same-dimension features could not be integrated into one representation in both conditions (meaningful and meaningless objects). Thus, Experiment 2 suggests that the same-dimension features could not be integrated into a representation of objects stored in VWM, regardless of the integrated clues. The present study provides supporting evidences for the weak object-based theory by claiming that manipulation of variables such as experimental paradigm and stimulus property exerts no effect on the memorization of same- dimensional features.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： When the associations among objects in the scene tend to remain unchanged as the time progressed, the repeated associations would guide attention to the target’s location more efficiently compared with the new context that changed across blocks, which is known as the contextual cuing effect. Though the process of the spatial layout has been widely interpreted, some studies that has investigated the role of object’s identities in contextual cuing effect were limited to the Euclidean property. The topological property, one of the most important objects’ identities referring to visual perception, was largely neglected. In this study, we aimed to manipulate configurations with topological property, Euclidean property, combined property as well as random configurations to test whether the predictability of the target associated with the topological property has the superiority relative to the Euclidean property. In Experiment one, a classic contextual cuing task was performed. Four types of configurations were randomly presented in the experiment. Experiment two was divided into two sessions, the studying session and the testing session. In the studying session, 24 configurations were repeated throughout the entire session, which was used to develop the learning effect. In the testing session, the previous 24 configurations were transformed into three groups, the topological repeated configurations, the Euclidean repeated configurations and the combined configurations. Meanwhile, eight random configurations were introduced as the baseline to measure the contextual cuing effect. In Experiment three, after the regularities of contexts had been learned, the topological properties of the target (experiment 3a) or distractors (experiment 3b) had been changed respectively. We explore whether topological changed configurations could capture attention by generating “new object” or lift the bound between topological regularities of the context and corresponding spatial layouts. In Experiment one, the main effects and the interaction between configuration and epoch were significant, indicating that all the three different repeated configurations obtained a remarkable contextual cuing effect. Further analysis showed that the reaction time in topological repeated configuration was faster than that in the random configuration in the 1st epoch, while the Euclidean repeated configuration had faster RTs than the random configuration from the 2nd epoch. In Experiment two, only the main effect of epoch was significant for the studying session, revealing an obvious learning effect. After configurations transformed, compared to the matched configurations in the learning session, RTs in both the topological repeated configuration and the Euclidean repeated configuration were significantly increased. Furthermore, the RTs of the topological repeated configuration were faster than the random configuration, while the RTs of the Euclidean repeated configuration were slower than the random configuration. The results demonstrated that the object’s property played an important role in contextual cuing effect, and the stability of topological-target associations made a greater contribution than Euclidean-target associations did in maintaining the contextual cuing effect. In Experiment three, both sub-experiments showed a significant learning effect in the studying session. For the testing session of Experiment 3a, the reaction time was not affected when the topological property of the target has changed. However, the accuracy of the topological changed configuration was significantly decreased than the topological repeated configuration of the Experiment 3b. Thus, Experiment three clarified the increased reaction time in the Euclidean repeated configuration, suggesting that contextual regularities of topological properties were bound to corresponding spatial layout. When topological regularities distorted, the "contextual confusion" came forth and made participants unable to utilize the context to guide attention to the target location effectively. For the first time, we have verified that the associations between objects’ topological property and the target could produce behavioral benefit than the Euclidean associations do. The association could probably be regarded as an informative cue to guide attention to the target location more efficiently. Nevertheless, the predictability of topological configuration takes priorities over Euclidean configuration during the learning course, and the association between objects’ topological property and the target has a more important significance in maintaining the contextual cuing effect.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Visual working memory (VWM) consolidation refers to the process of transforming a fleeting sensory representation into a relatively durable VWM representation which could be maintained briefly. It plays an important role in the process of visual information. In recent years, researchers have begun to shift the research focus from the time course of consolidation process to the consolidation capacity. They have found that consolidation capacity not only depends on the number of items which could be consolidated at the same time, but could be also affected by the allocation of attention resources caused by spatial scale. However, the simultaneous-sequential paradigm used in previous studies might be interfered with by some extraneous variables, such as the location of stimulus presentation, resulting in the inconsistent results of VWM consolidation studies.In Experiment 1, two masked colored patches (targets) were briefly presented (either simultaneous or sequential) within a virtual large circle (10� to 15� but 50% at 8�) or a virtual small circle (5.2� to 7.9� but 50% at 8�), and each condition was presented in different blocks of trials. Following the targets, a blank screen preceded the onset of a colored probe. Participants were asked to memorize the targets frames and indicate by a button press whether the probe was the same as any one of the targets. The results show that no difference was found between sequential and simultaneous presentation conditions, while the performance for small circle presentation was better than that for large circle presentation. These results correspond with previous studies and suggest that the variation of attention scope has no impact on the consolidation capacity. In Experiment 2, a colored target was presented, follow by two masked colored patches. Participants needed to judge if the target matched any of the masked colored patches. The variation of presentation scope was identical to that of Experiment 1. The results show no significant difference between the large and small attention scope condition. These results show no evidence for the effect of attention scope on the perceptual process and suggest that attention resource allocation caused by attention scope could affect the probability of VWM consolidation, but it does not influence the consolidation capacity.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Retro-cue effect (RCE) refers to the phenomenon that individuals can use retro-cues to improve their visual working memory (VWM) performance of target items after the disappearance of memory targets. To explain the mechanism of RCE in VWM, five different hypotheses have been proposed by previous studies: the hypothesis of enhancing target representations, the hypothesis of forgetting non-target representations, the hypothesis of preventing memory degradation, the hypothesis of preventing interference from probe array and the hypothesis of cognitive phase separation. Although RCE has been repeatedly observed in previous studies, the mechanism of RCE remains unclear. In this study, we conducted three experiments to test these hypotheses.In Experiment 1, participants were asked to memorize four colors in a recall task. They needed to recall the color of the target item when the probe array presented. There are three experimental conditions, the normal cue condition, the short interval no-cue condition, and the long interval no-cue condition. In the normal cue condition, a memory array (four colored squares) presented for 200 ms. Then, the memory array disappeared for 450 ms and a retro-cue presented, followed by a 900 ms blank. Then the probe array presented. In the short interval no-cue condition and long interval no-cue condition, no retro-cue presented after the memory array, but the probe array would present after the memory array disappeared for 450 ms (short interval no-cue condition) or 1400 ms (long interval no-cue condition). The design and procedure of Experiment 2 were similar to those of Experiment 1, except we used a grey-wheel cue condition and a colored-wheel cue condition to replace the long interval no-cue condition. These two new conditions were similar to the normal cue condition, except the retro-cue would appear with a distractor of a gray wheel (grey-wheel cue condition) or with a distractor of a colored wheel (colored-wheel cue condition). The design and procedure of Experiment 3 were similar to those of Experiment 2, except a long-grey-wheel short-cue condition and a long-grey-wheel long-cue condition were used to replace the normal cue condition and colored cue condition. In the long-grey-wheel short-cue condition, the retro-cue presented for 100 ms, but the grey wheel presented for 1000 ms. In the long-grey-wheel long-cue condition, the retro-cue and grey wheel presented for 1000 ms.The results of Experiment 1 showed that there was no significant difference in memory performance between the short interval no-cue condition and long interval no-cue condition, while the performance of the normal cue condition was better than that of short and long interval no-cue conditions. The results of Experiment 2 showed that participants obtained the RCE under the normal cue, the grey-wheel cue, and the colored-wheel cue conditions. However, the degrees of RCE obtained by these three conditions were different (normal cue > grey-wheel cue > colored-wheel cue). The results of Experiment 3 showed that participants obtained the RCE under the grey-wheel cue condition, the long-grey-wheel short-cue condition, and long-grey-wheel long-cue condition. The degree of RCE obtained by these three conditions was the same. The results of the present study supported the hypothesis of cognitive phase separation, which suggested that the retro-cue can separate the internal attention reallocation process and decision-making process, avoiding cognitive interference from the probe display. In addition, when the retro-cue was accompanied by the distractors, the type of distractors (rather than the presentation time) affected the degree of RCE. This study provides further evidence for the hypothesis of cognitive phase separation, which is crucial to solve the debate on the mechanism of RCE and to understand the relationship between attention and VWM.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Studies on how long-term memory affects working memory (WM) have found that long-term memory can enhance WM processing. However, these studies only use item memory as the representation of long-term memory. In addition to item memory, associative memory is also an essential part of long-term memory. The associative memory and item memory involve different cognitive mechanisms and brain areas. The purpose of the present study was to investigate how associative memory affects WM processing. Before the WM task, participants were asked to store 16 pairs of dissimilar pictures into long-term memory. The participants would obtain the associative memory of these pairs of pictures in the long-term memory. The WM task was a change detection paradigm. Memory pictures in the memory array appeared in pairs (associative condition) or out of pairs (independent condition). In Experiment 1, the memory array with 6 items (3 pairs) was presented for 500 ms or 1000 ms. After a 1000 ms interval, participants needed to determine whether the probe item was the same as the memory array. The design and procedure of Experiment 2 were similar to those of Experiment 1, except that memory array was presented for only 500 ms, and 2 items (1 pairs) and 4 terms (2 pairs) were added in set size condition. Alpha power of electroencephalogram (EEG) was also collected and analyzed in Experiment 2. The results in Experiment 1 showed that WM capacity and accuracy were significantly lower in the associative condition than in the independent condition (for both presentation-time conditions: 500ms and 1000ms). The results in Experiment 2 showed that the alpha power in the independent condition increased as the memory set size increased (2 items < 4 items < 6 items), while the alpha power in the associative condition reached the asymptote when the set size was 4 (2 items < 4 items = 6 items). Both of these two experiments' results showed that WM capacity in the associative condition was lower than that in the independent condition. In conclusion, long-term associative representations inhibit the current WM processing and decrease WM capacity. This inhibitory effect is not affected by the length of encoding time. It implies that the reason for the increase of WM load by associative memory may come from the disorder of attention distribution.
Subjects: Psychology >> Social Psychology submitted time 2023-03-27 Cooperative journals: 《心理学报》
Abstract： Contextual cueing refers to the global properties of a context or scene used to search for specific objects and regions. Chun and Jiang (1998) found that in a visual search, the reaction time to repeated configurations was shorter than the reaction time to newly generated configurations. The benefit of repeated context-target association is widely known as the contextual-cueing effect, which indicates that the subject has learned the contextual association by which attention is guided to facilitate the searching. However, the learning of contextual cueing lacks adaptability. When the subject has learned a set of contexts, it is difficult to update a new target into existing contexts (re-learning) or to learn a new set of contexts (new-learning). Previous studies have shown that restarted learning processes can facilitate the learning of new context-target associations, while updating old contexts is associated with the scope of attention. Notably, positive emotions could broaden the scope of attention and break the cognitive fixation on old processes; therefore, it is possible to improve the adaptability of contextual-cueing learning via positive emotions. This study aimed to explore whether positive emotions could enhance the adaptability of contextual learning. To this end, we recruited a sample of 18 young adults with positive and neutral affective priming as experimental conditions and control conditions, respectively, which allowed us to explore the contextual-cueing effect under the conditions of re-learning and new-learning. It should be noted that contextual cueing was defined in operation as the reaction time to the newly generated configuration minus that to the repeated configuration. The experiment was divided into two phases: the learning phase and the switch phase. In the learning phase, the subjects learned a set of contextual cues. In the switch phase, with the contextual-cueing effect as the dependent variable, a repeated measures ANOVA was conducted with the emotional valence (positive versus neutral), the new contextual-cueing learning type (re-learning versus new-learning), and the time phase (early phase versus late phase). The results indicated that neutral emotions did not facilitate contextual-cueing learning irrespective of the new contextual-cueing learning type. However, positive emotion improved learning in the new-learning condition, in which the contextual-cueing effect was higher in positive emotions than in neutral emotions both in the late phase and the early phase, whereas the re-learning condition did not show any sign of a contextual- cueing effect above zero. This study indicates that positive emotions can improve the adaptability of contextual-cueing learning and that the underlying mechanism restarts learning processing, which fails to prevent an automatic retrieval of the old presentations caused by similarity. Therefore, it facilitates the learning of new contextual cueing but does not update learned contextual cueing.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract： The 6061-T6 aluminium alloy was modified by multi-pass friction stir process with air or water cooling. Corrosion behavior of the processed zone was investigated by immersion test and electrochemical corrosion test, as well as optical microscopy, SEM and TEM. The results show that the grain size of stirred zone was successfully refined and its corrosion resistance became better obviously after the base metal was modified by FSP with different cooling methods. Compared with the base metal, the nugget zone exhibited higher free-corrosion potential, smaller corrosion current density and greater corrosion impedance. Compared to FSP with water-cooling, the nugget zone prepared by FSP with air-cooling showed better corrosion resistance.
Subjects: Psychology >> Cognitive Psychology Subjects: Psychology >> Experimental Psychology submitted time 2022-06-07
Abstract：
Contextual cueing refers to the global properties of a context or scene used to search for specific objects and regions. Chun and Jiang (1998) found that in a visual search, the reaction time to repeated configurations was shorter than the reaction time to newly generated configurations. The benefit of repeated context–target association is widely known as the contextual-cueing effect, which indicates that the subject has learned the contextual association by which attention is guided to facilitate the searching. However, the learning of contextual cueing lacks adaptability. When the subject has learned a set of contexts, it is difficult to update a new target into existing contexts (re-learning) or to learn a new set of contexts (new-learning). Previous studies have shown that restarted learning processes can facilitate the learning of new context–target associations, while updating old contexts is associated with the scope of attention. Notably, positive emotions could broaden the scope of attention and break the cognitive fixation on old processes; therefore, it is possible to improve the adaptability of contextual-cueing learning via positive emotions.
This study aimed to explore whether positive emotions could enhance the adaptability of contextual learning. To this end, we recruited a sample of 18 young adults with positive and neutral affective priming as experimental conditions and control conditions, respectively, which allowed us to explore the contextual-cueing effect under the conditions of re-learning and new-learning. It should be noted that contextual cueing was defined in operation as the reaction time to the newly generated configuration minus that to the repeated configuration.
The experiment was divided into two phases: the learning phase and the switch phase. In the learning phase, the subjects learned a set of contextual cues. In the switch phase, with the contextual-cueing effect as the dependent variable, a repeated measures ANOVA was conducted with the emotional valence (positive versus neutral), the new contextual-cueing learning type (re-learning versus new-learning), and the time phase (early phase versus late phase).
The results indicated that neutral emotions did not facilitate contextual-cueing learning irrespective of the new contextual-cueing learning type. However, positive emotion improved learning in the new-learning condition, in which the contextual-cueing effect was higher in positive emotions than in neutral emotions both in the late phase and the early phase, whereas the re-learning condition did not show any sign of a contextual-cueing effect above zero.
This study indicates that positive emotions can improve the adaptability of contextual-cueing learning and that the underlying mechanism restarts learning processing, which fails to prevent an automatic retrieval of the old presentations caused by similarity. Therefore, it facilitates the learning of new contextual cueing but does not update learned contextual cueing.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Geography submitted time 2021-12-12 Cooperative journals: 《干旱区研究》
Abstract：基于1954—2018年皇甫川流域长时间序列降水量、径流量和输沙量监测数据，运用线性趋势法、Mann-Kendall检验、累积距平法等方法研究了皇甫川流域水沙周期演变特征，应用水文分析法定量评估了降水变化和人类活动对皇甫川流域径流量和输沙量变化的贡献率。研究结果表明：皇甫川流域降水量随时间变化呈不明显减小趋势，而径流量和输沙量随时间变化却呈显著减小趋势，且径流量减少趋势大于输沙量减少趋势。径流量和输沙量均从1986年发生由丰到枯的突变。以1954—1986年为基准期，1987—2018年人类活动对皇甫川流域径流量和输沙量的影响分别为83.04%和75.24%，降水变化对皇甫川流域径流量和输沙量影响分别为16.96%和24.76%。突变年前后输沙量出现明显的下降，产流能力对输沙量变化的贡献率超过了85%。降水变化和人类活动是造成皇甫川流域水沙减少的影响因素，其中流域内逐年增强的人类活动是促使皇甫川流域径流和输沙减少的主要因素，而气候变化引起的降水减少是次要因素。
Subjects: Geosciences >> Geography submitted time 2020-06-02 Cooperative journals: 《干旱区地理》
Abstract： 针对陇中黄土丘陵沟壑区土壤水蚀过程复杂且难以有效预测的问题，以定西市安家沟水土保持试验站2005-2016年1 }12月人工草地径流场试验数据为主要来源，将流域月降雨量、月侵蚀性降雨量、月径流量、月降雨强度、径流场面积、径流场坡度、土壤砂粒含量、土壤粘粒含量8个因子作为输入因子，月土壤水蚀量作为输出，运用偏最小二乘法(Partial Least-Squares Regression,PLSR)和长短期记忆(Long Short-Term Memory,LSTM)循环神经网络建立人工草地土壤水蚀预测模型，并利用BP ( Back Propagation ) , RNN ( Recurrent Neural Network ) , LSTM常见神经网络模型，对模型的有效性进行评估。结果表明:PLSR将模型8个输入因子减少为4个，从而有效解决LSTM神经网络模型对样本数量要求过高的问题;PLSR和LSTM神经网络模型的结合可以有效提高模型对人工草地土壤水蚀过程的预测精度和收敛速度，预测结果的平均相对误差小于4%，相关系数高于其他3种神经网络模型，而迭代次数、均方根误差和平均绝对误差均低于其他3种模型;研究发现坡度对人工草地土壤水蚀过程影响较为明显，降雨量小于25 mm时，人工草地土壤水蚀量不会随坡度增加而明显增长，但当降雨量超过25 mm时，人工草地土壤水蚀量会随坡度明显增加。PLSR-LSTM神经网络土壤水蚀预测模型可以准确预测陇中黄土丘陵沟壑区人工草地土壤水蚀量，为该地区水土流失的准确预报提供新的思路和方法。
Subjects: Biology >> Botany >> Applied botany submitted time 2020-03-06 Cooperative journals: 《广西植物》
Abstract：为了探究外来红树植物拉关木对乡土红树植物的化感作用，本研究观察了不同浓度（0.1、0.3、0.5 g·mL-1）的拉关木根、叶水浸提液对乡土红树植物桐花树和正红树的胚轴（种子）萌发、幼苗生长及叶片抗氧化酶活性的影响。结果显示：拉关木水浸提液对桐花树种子的成苗率、萌发指数和根长均存在抑制作用，其中，对根长的抑制作用随水浸提液浓度的提高而增强。根水浸提液对桐花树幼苗的根长、苗高、生物量等生长指标的影响总体上均表现为低浓度促进，高浓度抑制。拉关木水浸提液对正红树胚轴的萌发率、萌发指数、生长指标均表现为促进作用，且根0.1、0.3 g·mL-1 处理组的芽长以及根、叶0.1、0.3 g·mL-1 处理组的生物量显著大于对照组。拉关木水浸提液对正红树幼苗的生物量也表现为促进作用。抗性生理方面，随着拉关木水浸提液浓度的升高，桐花树和正红树幼苗SOD 活性降低，正红树幼苗POD 活性在根0.3 g·mL-1 和叶0.1 g·mL-1 处理组显著高于对照。研究结果表明，不同乡土植物对拉关木化感作用的敏感性不同，拉关木水浸提液抑制了桐花树的生长，而对正红树的生长则表现出一定程度的促进作用。
Subjects: Biology >> Zoology submitted time 2018-12-25 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在探讨过瘤胃不饱和脂肪对安格斯牛生长性能和牛肉脂肪酸组成的影响。选用24头平均体重为（447.78±2.53） kg、17~18月龄安格斯阉公牛，随机分为4组，每组6头。第1组为对照组，饲喂基础饲粮，第2、3和4组分别按照干物质采食量的2.0%、4.0%和6.0%添加过瘤胃不饱和脂肪。试验全期77 d，其中预试期10 d、正试期67 d。结果表明：1）各组平均日增重、平均日采食量和料重比之间差异均不显著（P＞0.05）。2）第3组的粗蛋白质表观消化率显著高于第1组和第4组（P＜0.05），第3组和第4组的粗脂肪表观消化率显著高于第1组（P＜0.05），第1组和第2组的酸性洗涤纤维表观消化率显著高于第4组（P＜0.05）。3）第4组的背膘厚度显著高于第1组（P＜0.05），各组的屠宰率、净肉率和眼肌面积之间差异均不显著（P＞0.05）,各组的pH、剪切力、蒸煮损失、失水率、肉色及肌肉化学成分之间差异均不显著（P＞0.05）。4）第1组背最长肌中C18:0含量显著高于第2组和第3组（P＜0.05），第2组C20:4n6含量显著高于第1组和第4组（P＜0.05），第2、3和4组饱和脂肪酸含量分别比第1组降低了8.41%、10.26%和5.48%，单不饱和脂肪酸含量分别提高了6.37%、9.41%和6.72%，多不饱和脂肪酸含量则分别提高了69.78%、33.19%和9.36%，但差异均不显著（P＞0.05）。5）育肥前期第2、3和4组血清丙二醛含量显著低于第1组（P＜0.05），育肥后期第3组和第4组血清丙二醛含量显著低于第1组（P＜0.05）。在本试验条件下，饲粮中添加过瘤胃不饱和脂肪对肉牛平均日采食量和平均日增重无显著影响，有利于提高饲粮粗蛋白质和粗脂肪的表观消化率，可提高肉牛背膘厚度和机体的抗氧化能力，改善牛肉脂肪酸的组成；综合考虑，安格斯牛饲粮中过瘤胃不饱和脂肪最适宜的添加量为饲粮干物质采食量的4.0%。
Subjects: Biology >> Ecology submitted time 2018-06-09 Cooperative journals: 《生态学报》
Abstract：以1995、2003、2010、2015年4期遥感影像数据为基础，对武汉、长沙、南昌为例的长江中游城市20年不透水面增长及驱动因素进行研究。结果表明，三城市不透水面增长显著，接近预警水平，格局呈突围扩张的基本态势；现阶段武汉不透水面主要为城郊面源"零星"增长模式贡献较大；长沙、南昌则主要来源于新城"线式"延伸及其内部"面式"填充模式；道路投资、区划政策、城市规划控制、固定资产投资、房产投资、人口增长、透水技术等是影响三城市不透水增长的主要因素，但各因素影响敏感度在三城市中又有差异；三城市可从强化城乡规划的管理措施、控制过热的房地投资经济政策措施、平衡区域人口格局的社会政策措施以及推广透水材料和技术的科技措施等方面来缓解不透水率的增长。
Subjects: Computer Science >> Integration Theory of Computer Science submitted time 2018-05-20 Cooperative journals: 《计算机应用研究》
Abstract： Voiceprint recognition was one of the most popular biometric identification technologies, which could identify a speaker based on his voice. This paper proposed CDRNN, a voiceprint recognition scheme. CDRNN combined CNN and Deep RNN into a unified model and took advantages of both of them. For CNN was good at extracting characteristics from images, it could generate several spectrograms based on the original voice signal at first. And then, CNN would extract unique features from these spectrograms. . Finally, Deep RNN would output the speaker's identification based on these unique features. Simulation results show that CDRNN performs better than GMM-UBM and DNN-based approach.
Subjects: Medicine, Pharmacy >> Preclinical Medicine submitted time 2017-12-21 Cooperative journals: 《南方医科大学学报》
Abstract： Objective To investigate the expression of mir-106b in esophageal squamous cell carcinoma (ESCC) tissue and analyze its correlation with the clinicopathologic features of ESCC. Methods A total of 200 fresh surgical specimens of ESCC and adjacent tissues collected between 2001 and 2007 were examined for expressions of mir-106b using real-time PCR (RT-PCR). Northern blot analysis for mir-106b was performed in 4 pairs of samples to confirm the RT-PCR results. The relationship between mir-106b expression and clinicopathological features and prognosis of the patients were analyzed. Results Mir-106b was expressed at significantly higher levels in ESCC tissues than in the paired adjacent tissues.Overexpression of mir-106b was associated with lymph node metastasis, stage of TNM classification and smoking (P<0.05).The survival rate of patients with low mir-106b expression was higher than that of patients with high mir-106b expression (60 vs 37 months, P=0.024). Cox regression analysis indicated that the expression of mir-106b, lymph node metastasis and smoking were independent prognostic factors for ESCC (P<0.05). Conclusion Mir-106b is overexpressed in ESCC tumors, and its overexpression is strongly associated with lymph node metastasis and a poor prognosis. Mir-106b expression is an independent prognostic factor for ESCC and can serve as a biomarker for diagnosis and prognostic evaluation of ESCC.
Subjects: Biology >> Zoology submitted time 2017-10-23 Cooperative journals: 《动物营养学报》
Abstract：本试验旨在研究长期饲喂高精料饲粮下添加复合缓冲剂（碳酸氢钠、氧化镁、丁酸钠）对奶山羊乳成分、血浆生化指标及激素含量的影响。选择8头安装门静脉及肝静脉瘘管处于泌乳中期的奶山羊随机分为2组，分别饲喂基础饲粮（高精料饲粮组，HG组）和基础饲粮+复合缓冲剂（高精料饲粮+复合缓冲剂组，BG组）。预试期为7 d，正试期143 d。结果显示：与HG组相比，复合缓冲剂显著升高采食后0~10 h瘤胃液pH平均值（P0.05），对肝脏组织中甘油三酯和总蛋白含量无显著影响（P>0.05）；复合缓冲剂显著降低门静脉血浆中胰岛素和胰高血糖素的含量(P0.05)；复合缓冲剂显著或极显著升高产奶量、乳脂率、乳蛋白率、乳非脂固形物率（P<0.05或P<0.01）。综合得出，在长期高精料饲粮饲喂条件下，碳酸氢钠、氧化镁、丁酸钠的复合缓冲剂能通过影响奶山羊血浆生化指标及激素含量，影响体机营养物质代谢，最终有效提高产乳量与改善乳品质。
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