In this article,a novel logic which concerns with the natural property of comprehension is presented,and the cognitive state of the agent is also considered. The cognitive comprehension operator is put forward,the log...In this article,a novel logic which concerns with the natural property of comprehension is presented,and the cognitive state of the agent is also considered. The cognitive comprehension operator is put forward,the logical system is established,and then the axioms and the properties of the system are discussed. Finally,the application of the cognitive comprehension logic in the understanding of the metaphor is showed.展开更多
This study presents a general optimal trajectory planning(GOTP)framework for autonomous vehicles(AVs)that can effectively avoid obstacles and guide AVs to complete driving tasks safely and efficiently.Firstly,we emplo...This study presents a general optimal trajectory planning(GOTP)framework for autonomous vehicles(AVs)that can effectively avoid obstacles and guide AVs to complete driving tasks safely and efficiently.Firstly,we employ the fifth-order Bezier curve to generate and smooth the reference path along the road centerline.Cartesian coordinates are then transformed to achieve the curvature continuity of the generated curve.Considering the road constraints and vehicle dynamics,limited polynomial candidate trajectories are generated and smoothed in a curvilinear coordinate system.Furthermore,in selecting the optimal trajectory,we develop a unified and auto-tune objective function based on the principle of least action by employing AVs to simulate drivers’behavior and summarizing their manipulation characteristics of“seeking benefits and avoiding losses.”Finally,by integrating the idea of receding-horizon optimization,the proposed framework is achieved by considering dynamic multi-performance objectives and selecting trajectories that satisfy feasibility,optimality,and adaptability.Extensive simulations and experiments are performed,and the results demonstrate the framework’s feasibility and effectiveness,which avoids both dynamic and static obstacles and applies to various scenarios with multi-source interactive traffic participants.Moreover,we prove that the proposed method can guarantee real-time planning and safety requirements compared to drivers’manipulation.展开更多
Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of li...Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of life. The dorsolateral prefrontal cortex (DLPFC) has been a good target site for transcranial direct current stimulation (tDCS) due to its intense involvement in working memory. In our 2018 study, tDCS improved visual-verbal working memory in healthy subjects. Objective: This study examines the effects of tDCS on ADHD patients, particularly on verbal working memory. Methods: We conducted an experiment involving verbal working memory of two modalities, visual and auditory, and a sustained attention task that could affect working memory in 9 ADHD patients. Active or sham tDCS was applied to the left DLPFC in a single-blind crossover design. Results: tDCS significantly improved the accuracy of visual-verbal working memory. In contrast, tDCS did not affect auditory-verbal working memory and sustained attention. Conclusion: tDCS to the left DLPFC improved visual-verbal working memory in ADHD patients, with important implications for potential ADHD treatments.展开更多
Rhythm,as a prominent characteristic of auditory experiences such as speech and music,is known to facilitate attention,yet its contribution to working memory(WM)remains unclear.Here,human participants temporarily reta...Rhythm,as a prominent characteristic of auditory experiences such as speech and music,is known to facilitate attention,yet its contribution to working memory(WM)remains unclear.Here,human participants temporarily retained a 12-tone sequence presented rhythmically or arrhythmically in WM and performed a pitch change-detection task.Behaviorally,while having comparable accuracy,rhythmic tone sequences showed a faster response time and lower response boundaries in decision-making.Electroencephalographic recordings revealed that rhythmic sequences elicited enhanced non-phase-locked beta-band(16 Hz–33 Hz)and theta-band(3 Hz–5 Hz)neural oscillations during sensory encoding and WM retention periods,respectively.Importantly,the two-stage neural signatures were correlated with each other and contributed to behavior.As beta-band and theta-band oscillations denote the engagement of motor systems and WM maintenance,respectively,our findings imply that rhythm facilitates auditory WM through intricate oscillation-based interactions between the motor and auditory systems that facilitate predictive attention to auditory sequences.展开更多
In recent years, cognitive difficulties associated with normal aging and dementia have been receiving increased attention from both public and scientific communities. With an increase in overall lifespan, promoting he...In recent years, cognitive difficulties associated with normal aging and dementia have been receiving increased attention from both public and scientific communities. With an increase in overall lifespan, promoting healthy cognition has become a priority and a necessity for minimizing and preventing individual and societal burdens associated with cognitive dysfunctions in the elderly. The general awareness concerning the efficacy of preventive(e.g., lifestyles) and palliative treatment strategies of cognitive impairments, related to either healthy or unhealthy trajectories in cognitive aging, is continuously rising. There are several therapeutic strategies which can be broadly classified as either pharmacological or non-pharmacological/psychosocial. In face of the modest evidence for success of pharmacological treatments, especially for dementia related impairments, psychosocial interventions are progressively considered as a complementary treatment. Despite the relative spread of psychosocial interventions in clinical settings, research in this area is rather scarce with evidence for success of these therapies remaining controversial. In this work we provide an evidence based perspective on cognitive intervention(s) for healthy aging, pre-dementia(mild cognitive impairment), and dementia populations. Current evidence and future directions for improving cognitive functions in the elderly are discussed as well.展开更多
Posttraumatic stress disorder(PTSD) is a common anxiety disorder characterised by its persistence of symptoms after a traumatic experience. Although some patients can be cured, many do not benefit enough from the psyc...Posttraumatic stress disorder(PTSD) is a common anxiety disorder characterised by its persistence of symptoms after a traumatic experience. Although some patients can be cured, many do not benefit enough from the psychological therapies or medication strategies used. Many researchers use animal models to learn more about the disorder and several models are available. The most-used physical stressor models are single-prolonged stress, restraint stress, foot shock, stress-enhanced fear learning, and underwater trauma. Common social stressors are housing instability, social instability, earlylife stress, and social defeat. Psychological models are not as diverse and rely on controlled exposure to the test animal's natural predator. While validation of these models has been resolved with replicated symptoms using analogous stressors, translating new findings to human patients remains essential for their impact on the field. Choosing a model to experiment with can be challenging; this overview of what is possible with individual models may aid in making a decision.展开更多
Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is ...Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is expressed as a feature vector; second, a special hierarchical clustering algorithm is applied to present a discourse as a sentence group tree. In this paper, local reoccurrence measure is proposed to the selection of key phras and the evaluation of the weight of key phrases. Experimental results show our approach promising.展开更多
Three hypotheses have attempted to explain the phenomenon of contagious yawning. It has been hypothesized that it is a fixed action pattern for which the releasing stimulus is the observation of another yawn, that it ...Three hypotheses have attempted to explain the phenomenon of contagious yawning. It has been hypothesized that it is a fixed action pattern for which the releasing stimulus is the observation of another yawn, that it is the result of non-conscious mimicry emerging through close links between perception and action or that it is the result of empathy, involving the ability to engage in mental state attribution. This set of experiments sought to distinguish between these hypotheses by examining contagious yawning in a species that is unlikely to show nonconscious mimicry and empathy but does respond to social stimuli： the red-footed tortoise Geochelone carbonaria. A demonstrator tortoise was conditioned to yawn when presented with a red square-shaped stimulus. Observer tortoises were exposed to three conditions： observation of conditioned yawn, non demonstration control, and stimulus only control. We measured the number of yawns for each observer animal in each condition. There was no difference between conditions. Experiment 2 therefore increased the number of conditioned yawns presented. Again, there was no significant difference between conditions. It seemed plausible that the tortoises did not view the conditioned yawn as a real yawn and therefore a final experiment was run using video recorded stimuli. The observer tortoises were presented with three conditions： real yawn, conditioned yawns and empty background. Again there was no significant difference between conditions. We therefore conclude that the red-footed tortoise does not yawn in response to observing a conspecific yawn. This suggests that contagious yawning is not the result of a fixed action pattern but may involve more complex social processes [Current Zoology 57 （4）： 477-484, 2011].展开更多
Automatic kidney segmentation from abdominal CT images is a key step in computer-aided diagnosis for kidney CT as well as computeraided surgery. However, kidney segmentation from CT images is generally performed manua...Automatic kidney segmentation from abdominal CT images is a key step in computer-aided diagnosis for kidney CT as well as computeraided surgery. However, kidney segmentation from CT images is generally performed manually or semi-autornatically because of gray levels similarities of adjacent organs/tissues in abdominal CT images. This paper presents an efficient algorithm for segmenting kidney from serials of abdominal CT images. First, we extracted estimated kidney position （EKP） according to the statistical geometric location of kidney within the abdomen. Second, we analyzed the intensity distribution of EKP for several abdominal CT images and exploit an adaptive threshold searching algorithm to eliminate many other organs/tissues in the EKP. Finally, a novel region growing approach based on labeling is used to obtain the fine kidney regions. Experimental results are comparable to those of manual tracing radiologist and shown to be efficient.展开更多
Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]...Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]. It is not known, however, to what extent aging affects visual field repre-sentations and population receptive sizes in human primary visual cortex. Here we use func-tional MRI (fMRI) and population receptive field (pRF) modeling [6] to measure angular and ec-centric retinotopic representations and population receptive fields in primary visual cortex in healthy aging subjects ages 57 - 70 and in healthy young volunteers ages 24 - 36 (n = 9). Retinotopic stimuli consisted of black and white, drifting checkerboards comprising moving bars 11 deg in radius. Primary visual cortex (V1) was clearly identifiable along the calcarine sulcus in all hemispheres. There was a significant decrease in the surface area of V1 from 0 to 3 deg eccentricity in the aging subjects with respect to the young subjects (p = 0.039). The coherence of the fMRI% BOLD modulation was significantly decreased in the aging subjects compared to the young subjects in the more peripheral eccentricity band from 7 to 10 deg (p = 0.029). Finally, pRF sizes were significantly increased within the 0 to 3 deg foveal representation of V1 in the aging subjects compared to the young subjects (p = 0.019). Understanding the extent of changes that occur in primary visual cortex during normal aging is essential both for understanding the normal aging process and for comparisons of healthy, aging subjects with aging patients suffering from age-related visual and cortical disorders.展开更多
Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are in...Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are introduced first. Then two soft computational methods,genetic algorithms and back propagation (BP) neural network technology,are combined to the experiment on assisting in composing "two voice part inventions". The system presented in this paper is quite effective and satisfactory.展开更多
The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The numb...The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The number of plots/ha, stripped trees/ plot and stripped trees/ha was recorded during the pre-rainy, rainy and post-rainy seasons from August 2006 to May 2007. During data collection, altitude, aspect, season and other site predictor variables （e. g., roads and fire traces, water points, indigenous vegetation conservation areas, crop felds, human settlements, wattle scrubs, rocky areas, open grasslands, earlier stripped sites and roost sites） were recorded for each plot in association with selected predictor variables within plantation estates. Data on the number of stripped plots/ha, stripped trees/plot and stripped trees/ha were analysed as dependent variables using the Generalised Linear Model （GLM） through SPSS version 15 （2006） to determine which predictor variables were significantly related to bark stripping. Differences between means were tested using Bonferroni tests with a 5 % level of significance. Our findings show that bark stripping of pine trees by baboons occurred at all altitudes and aspects. Overall, the number of bark stripped trees/ha did not significandy vary by season. The number of bark stripped plots/ha was lower during the pre-rainy season than the rainy season, whereas the number of bark stripped trees/plot was higher during the pre-rainy than the rainy season. Bark stripping of pines occurred more often in the vicinities of areas with abundant food and water展开更多
In this paper, the nonlinear Hunter–Saxton equation, which is a famous partial differential equation,is solved by using a hybrid numerical method based on the quasilinearization method and the bivariate generalized f...In this paper, the nonlinear Hunter–Saxton equation, which is a famous partial differential equation,is solved by using a hybrid numerical method based on the quasilinearization method and the bivariate generalized fractional order of the Chebyshev functions(B-GFCF) collocation method. First, using the quasilinearization method,the equation is converted into a sequence of linear partial differential equations(LPD), and then these LPDs are solved using the B-GFCF collocation method. A very good approximation of solutions is obtained, and comparisons show that the obtained results are more accurate than the results of other researchers.展开更多
In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home rang...In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.展开更多
Closure or the presence of a ＂hole＂ is an emergent perceptual feature that can be extracted by the visual system early on. This feature has been shown to have perceptual advantages over openness or ＂no-hole＂. in t...Closure or the presence of a ＂hole＂ is an emergent perceptual feature that can be extracted by the visual system early on. This feature has been shown to have perceptual advantages over openness or ＂no-hole＂. in this study, we investigated when and how the human brain differentiates between ＂hole＂ and ＂no-hole＂ figures. Event-related potentials （ERPs） were recorded during a passive observation paradigm. Two pairs of simple figures （Experiment 1） and two sets of Greek letters （Experiment 2） were used as stimuli. The ERPs of ＂hole＂ and ＂no-hole＂ figures differed ~90 ms after stimulus onset： ＂hole＂ figures elicited smaller P1 and N1 amplitudes than ＂no-hole＂ figures. These suggest that both P1 and N1 components are sensitive to the difference between ＂hole＂ and ＂no-hole＂ figures; perception of ＂hole＂ and ＂no-hole＂ figures might be differentiated early during visual processing.展开更多
Dear Editor,Saccades and smooth-pursuit eye movements(SPEMs)are two categories of eye movements with very different kinematics,in particular very different acceleration and velocity ranges,differences that have contri...Dear Editor,Saccades and smooth-pursuit eye movements(SPEMs)are two categories of eye movements with very different kinematics,in particular very different acceleration and velocity ranges,differences that have contributed to the notion of largely segregated underlying neuronal circuits.For instance,it has been suggested that distinct wellsegregated pools of oculomotor vermis(OMV)Purkinje cells(PCs)are specialized for the fine-tuning of the relevant kinematic parameters characterizing each of them.展开更多
Chinese organization name recognition is hard and important in natural language processing. To reduce tagged corpus and use untagged corpus,we presented combing Co-training with support vector machines (SVM) and condi...Chinese organization name recognition is hard and important in natural language processing. To reduce tagged corpus and use untagged corpus,we presented combing Co-training with support vector machines (SVM) and conditional random fields (CRF) to improve recognition results. Based on principles of uncorrelated and compatible,we constructed different classifiers from different views within SVM or CRF alone and combination of these two models. And we modified a heuristic untagged samples selection algorithm to reduce time complexity. Experimental results show that under the same tagged data,Co-training has 10% F-measure higher than using SVM or CRF alone; under the same F-measure,Co-training saves at most 70% of tagged data to achieve the same performance.展开更多
In this paper, the 3-D Wavelet-Fractal coder was used to compress the hyperspectral remote sensing image, which is a combination of 3-D improved set partitioning in hierarchical trees （SPIHT） coding and 3-D fractal ...In this paper, the 3-D Wavelet-Fractal coder was used to compress the hyperspectral remote sensing image, which is a combination of 3-D improved set partitioning in hierarchical trees （SPIHT） coding and 3-D fractal coding. Hyperspectral image date cube was first translated by 3-D wavelet and the 3-D fractal compression ceding was applied to lowest frequency subband. The remaining coefficients of higher frequency sub-bands were encoding by 3-D improved SPIHT. We used the block set instead of the hierarchical trees to enhance SPIHT＇s flexibility. The classical eight kinds of affme transformations in 2-D fractal image compression were generalized to nineteen for the 3-D fractal image compression. The new compression method had been tested on MATLAB. The experiment results indicate that we can gain high compression ratios and the information loss is acceptable.展开更多
Detrimental immune response has a crucially important role in the development and progression of inflammatory eye diseases.Inflammatory mediators and proteolytic enzymes released by activated immune cells induce serio...Detrimental immune response has a crucially important role in the development and progression of inflammatory eye diseases.Inflammatory mediators and proteolytic enzymes released by activated immune cells induce serious injury of corneal epithelial cells and retinal ganglion cell which may result in the vision loss.Mesenchymal stem cells(MSCs)are regulatory cells which produce various immunosuppressive factors that modulate phenotype and function of inflammatory immune cells.However,several safety issues,including undesired differentiation and emboli formation,limit clinical use of MSCs.MSC-derived exosomes(MSC-Exos)are nano-sized extracellular vesicles which contain all MSC-derived immunoregulatory factors.Intraocular administration of MSCExos efficiently attenuated eye inflammation and significantly improved visual acuity in experimental animals without causing any severe side effects.As cell-free product,MSC-Exos addressed all safety issues related to the transplantation of MSCs.Therefore,MSC-Exos could be considered as potentially new remedy for the treatment of inflammatory eye diseases which efficacy should be explored in up-coming clinical trials.展开更多
Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythm...Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythms in harbor seals is critical to a cross-species hypothesis in evolutionary neuroscience that links vocal learning, rhythm perception, and synchronization. This study utilized analytical techniques that may best capture rhythmic structure in pup vocalizations with the goal of examining whether (1) harbor seal pups show rhythmic structure in their calls and (2) rhythms evolve over time. Calls of 3 wild-born seal pups were recorded daily over the course of 1-3 weeks;3 temporal features were analyzed using 3 complementary techniques. We identified temporal and rhythmic structure in pup calls across different time windows. The calls of harbor seal pups exhibit some degree of temporal and rhythmic organization, which evolves over puppyhood and resembles that of other species' in teractive comm un icati on. We suggest n ext steps for investigating call structure in harbor seal pups and propose comparative hypotheses to test in other pinniped species.展开更多
基金Foundation of Fujian Province of China (No.2008F3105)
文摘In this article,a novel logic which concerns with the natural property of comprehension is presented,and the cognitive state of the agent is also considered. The cognitive comprehension operator is put forward,the logical system is established,and then the axioms and the properties of the system are discussed. Finally,the application of the cognitive comprehension logic in the understanding of the metaphor is showed.
基金supported by the National Natural Science Foundation of China(the Key Project,52131201Science Fund for Creative Research Groups,52221005)+1 种基金the China Scholarship Councilthe Joint Laboratory for Internet of Vehicles,Ministry of Education–China MOBILE Communications Corporation。
文摘This study presents a general optimal trajectory planning(GOTP)framework for autonomous vehicles(AVs)that can effectively avoid obstacles and guide AVs to complete driving tasks safely and efficiently.Firstly,we employ the fifth-order Bezier curve to generate and smooth the reference path along the road centerline.Cartesian coordinates are then transformed to achieve the curvature continuity of the generated curve.Considering the road constraints and vehicle dynamics,limited polynomial candidate trajectories are generated and smoothed in a curvilinear coordinate system.Furthermore,in selecting the optimal trajectory,we develop a unified and auto-tune objective function based on the principle of least action by employing AVs to simulate drivers’behavior and summarizing their manipulation characteristics of“seeking benefits and avoiding losses.”Finally,by integrating the idea of receding-horizon optimization,the proposed framework is achieved by considering dynamic multi-performance objectives and selecting trajectories that satisfy feasibility,optimality,and adaptability.Extensive simulations and experiments are performed,and the results demonstrate the framework’s feasibility and effectiveness,which avoids both dynamic and static obstacles and applies to various scenarios with multi-source interactive traffic participants.Moreover,we prove that the proposed method can guarantee real-time planning and safety requirements compared to drivers’manipulation.
文摘Background: Working memory is an executive function that plays an important role in many aspects of daily life, and its impairment in patients with attention-deficit/hyperactivity disorder (ADHD) affects quality of life. The dorsolateral prefrontal cortex (DLPFC) has been a good target site for transcranial direct current stimulation (tDCS) due to its intense involvement in working memory. In our 2018 study, tDCS improved visual-verbal working memory in healthy subjects. Objective: This study examines the effects of tDCS on ADHD patients, particularly on verbal working memory. Methods: We conducted an experiment involving verbal working memory of two modalities, visual and auditory, and a sustained attention task that could affect working memory in 9 ADHD patients. Active or sham tDCS was applied to the left DLPFC in a single-blind crossover design. Results: tDCS significantly improved the accuracy of visual-verbal working memory. In contrast, tDCS did not affect auditory-verbal working memory and sustained attention. Conclusion: tDCS to the left DLPFC improved visual-verbal working memory in ADHD patients, with important implications for potential ADHD treatments.
基金supported by the National Natural Science Foundation of China(12171373)supported by the Fundamental Research Funds for the Central Universities of China(GK202207018).
文摘Rhythm,as a prominent characteristic of auditory experiences such as speech and music,is known to facilitate attention,yet its contribution to working memory(WM)remains unclear.Here,human participants temporarily retained a 12-tone sequence presented rhythmically or arrhythmically in WM and performed a pitch change-detection task.Behaviorally,while having comparable accuracy,rhythmic tone sequences showed a faster response time and lower response boundaries in decision-making.Electroencephalographic recordings revealed that rhythmic sequences elicited enhanced non-phase-locked beta-band(16 Hz–33 Hz)and theta-band(3 Hz–5 Hz)neural oscillations during sensory encoding and WM retention periods,respectively.Importantly,the two-stage neural signatures were correlated with each other and contributed to behavior.As beta-band and theta-band oscillations denote the engagement of motor systems and WM maintenance,respectively,our findings imply that rhythm facilitates auditory WM through intricate oscillation-based interactions between the motor and auditory systems that facilitate predictive attention to auditory sequences.
基金Supported by The Foundation for Science and Technology,FCT(SFRH/BD/64457/2009 and SFRH/BD/65213/2009,co-funded by FSE/POPH)project PIC/IC/83290/2007,which is supported by FEDER(POFC-COMPETE) and FCT
文摘In recent years, cognitive difficulties associated with normal aging and dementia have been receiving increased attention from both public and scientific communities. With an increase in overall lifespan, promoting healthy cognition has become a priority and a necessity for minimizing and preventing individual and societal burdens associated with cognitive dysfunctions in the elderly. The general awareness concerning the efficacy of preventive(e.g., lifestyles) and palliative treatment strategies of cognitive impairments, related to either healthy or unhealthy trajectories in cognitive aging, is continuously rising. There are several therapeutic strategies which can be broadly classified as either pharmacological or non-pharmacological/psychosocial. In face of the modest evidence for success of pharmacological treatments, especially for dementia related impairments, psychosocial interventions are progressively considered as a complementary treatment. Despite the relative spread of psychosocial interventions in clinical settings, research in this area is rather scarce with evidence for success of these therapies remaining controversial. In this work we provide an evidence based perspective on cognitive intervention(s) for healthy aging, pre-dementia(mild cognitive impairment), and dementia populations. Current evidence and future directions for improving cognitive functions in the elderly are discussed as well.
基金The Netherlands Organisation for Scientific Research(NWO),No.864.10.003(awarded to Judith R Homberg)
文摘Posttraumatic stress disorder(PTSD) is a common anxiety disorder characterised by its persistence of symptoms after a traumatic experience. Although some patients can be cured, many do not benefit enough from the psychological therapies or medication strategies used. Many researchers use animal models to learn more about the disorder and several models are available. The most-used physical stressor models are single-prolonged stress, restraint stress, foot shock, stress-enhanced fear learning, and underwater trauma. Common social stressors are housing instability, social instability, earlylife stress, and social defeat. Psychological models are not as diverse and rely on controlled exposure to the test animal's natural predator. While validation of these models has been resolved with replicated symptoms using analogous stressors, translating new findings to human patients remains essential for their impact on the field. Choosing a model to experiment with can be challenging; this overview of what is possible with individual models may aid in making a decision.
基金National High Technology Research and Development Program of China ( No.2006AA01Z139)Young NaturalScience Foundation of Fujian Province of China ( No.2008F3105)+1 种基金Natural Science Foundation of Fujian Province of China ( No.2006J0043)Fund of Key Research Project of Fujian Province of China (No.2006H0038)
文摘Automatic partition of Chinese sentence group is very important to the statistical machine translation system based on discourse. This paper presents an approach to this issue： first, each sentence in a discourse is expressed as a feature vector; second, a special hierarchical clustering algorithm is applied to present a discourse as a sentence group tree. In this paper, local reoccurrence measure is proposed to the selection of key phras and the evaluation of the weight of key phrases. Experimental results show our approach promising.
文摘Three hypotheses have attempted to explain the phenomenon of contagious yawning. It has been hypothesized that it is a fixed action pattern for which the releasing stimulus is the observation of another yawn, that it is the result of non-conscious mimicry emerging through close links between perception and action or that it is the result of empathy, involving the ability to engage in mental state attribution. This set of experiments sought to distinguish between these hypotheses by examining contagious yawning in a species that is unlikely to show nonconscious mimicry and empathy but does respond to social stimuli： the red-footed tortoise Geochelone carbonaria. A demonstrator tortoise was conditioned to yawn when presented with a red square-shaped stimulus. Observer tortoises were exposed to three conditions： observation of conditioned yawn, non demonstration control, and stimulus only control. We measured the number of yawns for each observer animal in each condition. There was no difference between conditions. Experiment 2 therefore increased the number of conditioned yawns presented. Again, there was no significant difference between conditions. It seemed plausible that the tortoises did not view the conditioned yawn as a real yawn and therefore a final experiment was run using video recorded stimuli. The observer tortoises were presented with three conditions： real yawn, conditioned yawns and empty background. Again there was no significant difference between conditions. We therefore conclude that the red-footed tortoise does not yawn in response to observing a conspecific yawn. This suggests that contagious yawning is not the result of a fixed action pattern but may involve more complex social processes [Current Zoology 57 （4）： 477-484, 2011].
基金National Natural Science Foundations of China (No.60601025, No.60701022, No.30770561)
文摘Automatic kidney segmentation from abdominal CT images is a key step in computer-aided diagnosis for kidney CT as well as computeraided surgery. However, kidney segmentation from CT images is generally performed manually or semi-autornatically because of gray levels similarities of adjacent organs/tissues in abdominal CT images. This paper presents an efficient algorithm for segmenting kidney from serials of abdominal CT images. First, we extracted estimated kidney position （EKP） according to the statistical geometric location of kidney within the abdomen. Second, we analyzed the intensity distribution of EKP for several abdominal CT images and exploit an adaptive threshold searching algorithm to eliminate many other organs/tissues in the EKP. Finally, a novel region growing approach based on labeling is used to obtain the fine kidney regions. Experimental results are comparable to those of manual tracing radiologist and shown to be efficient.
文摘Aging often results in reduced visual acuity from changes in both the eye and neural circuits [1-4]. In normally aging subjects, primary visual cortex has been shown to have reduced responses to visual stimulation [5]. It is not known, however, to what extent aging affects visual field repre-sentations and population receptive sizes in human primary visual cortex. Here we use func-tional MRI (fMRI) and population receptive field (pRF) modeling [6] to measure angular and ec-centric retinotopic representations and population receptive fields in primary visual cortex in healthy aging subjects ages 57 - 70 and in healthy young volunteers ages 24 - 36 (n = 9). Retinotopic stimuli consisted of black and white, drifting checkerboards comprising moving bars 11 deg in radius. Primary visual cortex (V1) was clearly identifiable along the calcarine sulcus in all hemispheres. There was a significant decrease in the surface area of V1 from 0 to 3 deg eccentricity in the aging subjects with respect to the young subjects (p = 0.039). The coherence of the fMRI% BOLD modulation was significantly decreased in the aging subjects compared to the young subjects in the more peripheral eccentricity band from 7 to 10 deg (p = 0.029). Finally, pRF sizes were significantly increased within the 0 to 3 deg foveal representation of V1 in the aging subjects compared to the young subjects (p = 0.019). Understanding the extent of changes that occur in primary visual cortex during normal aging is essential both for understanding the normal aging process and for comparisons of healthy, aging subjects with aging patients suffering from age-related visual and cortical disorders.
基金National Natural Science Foundation of China (No.60975076)
文摘Algorithmic composition is a very popular research field today. Bach's "two voice part invention" is the research object in this paper. The grammar and compositional rules of "invention" are introduced first. Then two soft computational methods,genetic algorithms and back propagation (BP) neural network technology,are combined to the experiment on assisting in composing "two voice part inventions". The system presented in this paper is quite effective and satisfactory.
基金funded by the African Forest Research network (AFORNET) Grant number 17/01/2005
文摘The aim of this study was to determine the susceptibility, intensity and distribution of pine trees to bark stripping by chacma baboons Papio ursinus in three plantations in the Eastern Highlands of Zimbabwe. The number of plots/ha, stripped trees/ plot and stripped trees/ha was recorded during the pre-rainy, rainy and post-rainy seasons from August 2006 to May 2007. During data collection, altitude, aspect, season and other site predictor variables （e. g., roads and fire traces, water points, indigenous vegetation conservation areas, crop felds, human settlements, wattle scrubs, rocky areas, open grasslands, earlier stripped sites and roost sites） were recorded for each plot in association with selected predictor variables within plantation estates. Data on the number of stripped plots/ha, stripped trees/plot and stripped trees/ha were analysed as dependent variables using the Generalised Linear Model （GLM） through SPSS version 15 （2006） to determine which predictor variables were significantly related to bark stripping. Differences between means were tested using Bonferroni tests with a 5 % level of significance. Our findings show that bark stripping of pine trees by baboons occurred at all altitudes and aspects. Overall, the number of bark stripped trees/ha did not significandy vary by season. The number of bark stripped plots/ha was lower during the pre-rainy season than the rainy season, whereas the number of bark stripped trees/plot was higher during the pre-rainy than the rainy season. Bark stripping of pines occurred more often in the vicinities of areas with abundant food and water
文摘In this paper, the nonlinear Hunter–Saxton equation, which is a famous partial differential equation,is solved by using a hybrid numerical method based on the quasilinearization method and the bivariate generalized fractional order of the Chebyshev functions(B-GFCF) collocation method. First, using the quasilinearization method,the equation is converted into a sequence of linear partial differential equations(LPD), and then these LPDs are solved using the B-GFCF collocation method. A very good approximation of solutions is obtained, and comparisons show that the obtained results are more accurate than the results of other researchers.
文摘In many songbirds, the space use of breeders is well studied but poorly understood for non-breeders. In common ravens, some studies of non-breeders indicate high vagrancy with large individual differences in home range size, whereas others show that up to 40% of marked non-breeders can be regularly observed at the same anthropogenic food source over months to years. The aim of this study was to provide new insights on ravens＇ behavior during dispersal in the Eastern Alps. We deployed Global Positioning System （GPS） loggers on 10 individuals to gather accurate spatial and temporal information on their movements to quantify： 1） the dimension of the birds＇ space use （home range size with seasonal effects and daily/long-term travel distances）, 2） how long they stayed in a dispersal stage of wandering as opposed to settling temporarily, and 3） their destination of movements. We recorded movements of up to 40km per hour, more than 160km within 1 day and more than 11,000 km within 20 months, indicating high vagrancy. Switching frequently between temporarily settling and travelling large distances in short time intervals leads to extensive home ranges, which also explains and com- bines the different findings in the literature. The destinations are rich anthropogenic food sources, where the birds spent on average 75% of their time. We discuss how ravens may find these ＂feeding hot spots＂ and which factors may influence their decision to stay/leave a site. The strong dependence on anthropogenic resources found in this population may have implications for site management and conservation issues.
基金supported by the National Natural Science Foundation of China(61005087,61263042)Science and Technology Project of Yunnan Province,China(2009CD018)+2 种基金Key Science and Technology Project of Department of Education,Yunnan Province,China(2010Z067)Science and Technology Basic Research Fund of Yunnan University,China(KL080012,030-WX069051)the Major Program of National Social Science Foundation of China(11 & ZD187)
文摘Closure or the presence of a ＂hole＂ is an emergent perceptual feature that can be extracted by the visual system early on. This feature has been shown to have perceptual advantages over openness or ＂no-hole＂. in this study, we investigated when and how the human brain differentiates between ＂hole＂ and ＂no-hole＂ figures. Event-related potentials （ERPs） were recorded during a passive observation paradigm. Two pairs of simple figures （Experiment 1） and two sets of Greek letters （Experiment 2） were used as stimuli. The ERPs of ＂hole＂ and ＂no-hole＂ figures differed ~90 ms after stimulus onset： ＂hole＂ figures elicited smaller P1 and N1 amplitudes than ＂no-hole＂ figures. These suggest that both P1 and N1 components are sensitive to the difference between ＂hole＂ and ＂no-hole＂ figures; perception of ＂hole＂ and ＂no-hole＂ figures might be differentiated early during visual processing.
基金This work was supported by grants from the Fundamental Research Funds for the Central Universities(GK202103132)Shaanxi Normal University,and the Scientific Research Foundation of Shaanxi Normal University(1110011181)of Chinaas a grant from the Deutsche Forschungsgemeinschaft(FOR 1847-A3 TH425/13-1),Germany.
文摘Dear Editor,Saccades and smooth-pursuit eye movements(SPEMs)are two categories of eye movements with very different kinematics,in particular very different acceleration and velocity ranges,differences that have contributed to the notion of largely segregated underlying neuronal circuits.For instance,it has been suggested that distinct wellsegregated pools of oculomotor vermis(OMV)Purkinje cells(PCs)are specialized for the fine-tuning of the relevant kinematic parameters characterizing each of them.
基金National Natural Science Foundations of China (No.60873179, No.60803078)
文摘Chinese organization name recognition is hard and important in natural language processing. To reduce tagged corpus and use untagged corpus,we presented combing Co-training with support vector machines (SVM) and conditional random fields (CRF) to improve recognition results. Based on principles of uncorrelated and compatible,we constructed different classifiers from different views within SVM or CRF alone and combination of these two models. And we modified a heuristic untagged samples selection algorithm to reduce time complexity. Experimental results show that under the same tagged data,Co-training has 10% F-measure higher than using SVM or CRF alone; under the same F-measure,Co-training saves at most 70% of tagged data to achieve the same performance.
基金National Natural Science Foundation of China (No.60975084)
文摘In this paper, the 3-D Wavelet-Fractal coder was used to compress the hyperspectral remote sensing image, which is a combination of 3-D improved set partitioning in hierarchical trees （SPIHT） coding and 3-D fractal coding. Hyperspectral image date cube was first translated by 3-D wavelet and the 3-D fractal compression ceding was applied to lowest frequency subband. The remaining coefficients of higher frequency sub-bands were encoding by 3-D improved SPIHT. We used the block set instead of the hierarchical trees to enhance SPIHT＇s flexibility. The classical eight kinds of affme transformations in 2-D fractal image compression were generalized to nineteen for the 3-D fractal image compression. The new compression method had been tested on MATLAB. The experiment results indicate that we can gain high compression ratios and the information loss is acceptable.
基金This work was supported by European Crohn’s and Colitis Organization(ECCO)(Grant“The role of galectin 3 in acute colitis”),Serbian Ministry of Science(Grant Nos.ON175069 and ON175103)Faculty of Medical Sciences University of Kragujevac(Grant No.MP01/18).
文摘Detrimental immune response has a crucially important role in the development and progression of inflammatory eye diseases.Inflammatory mediators and proteolytic enzymes released by activated immune cells induce serious injury of corneal epithelial cells and retinal ganglion cell which may result in the vision loss.Mesenchymal stem cells(MSCs)are regulatory cells which produce various immunosuppressive factors that modulate phenotype and function of inflammatory immune cells.However,several safety issues,including undesired differentiation and emboli formation,limit clinical use of MSCs.MSC-derived exosomes(MSC-Exos)are nano-sized extracellular vesicles which contain all MSC-derived immunoregulatory factors.Intraocular administration of MSCExos efficiently attenuated eye inflammation and significantly improved visual acuity in experimental animals without causing any severe side effects.As cell-free product,MSC-Exos addressed all safety issues related to the transplantation of MSCs.Therefore,MSC-Exos could be considered as potentially new remedy for the treatment of inflammatory eye diseases which efficacy should be explored in up-coming clinical trials.
文摘Puppyhood is a very active social and vocal period in a harbor seal's life Ph oca vitulina. An important feature of vocalizations is their temporal and rhythmic structure, and understanding vocal timing and rhythms in harbor seals is critical to a cross-species hypothesis in evolutionary neuroscience that links vocal learning, rhythm perception, and synchronization. This study utilized analytical techniques that may best capture rhythmic structure in pup vocalizations with the goal of examining whether (1) harbor seal pups show rhythmic structure in their calls and (2) rhythms evolve over time. Calls of 3 wild-born seal pups were recorded daily over the course of 1-3 weeks;3 temporal features were analyzed using 3 complementary techniques. We identified temporal and rhythmic structure in pup calls across different time windows. The calls of harbor seal pups exhibit some degree of temporal and rhythmic organization, which evolves over puppyhood and resembles that of other species' in teractive comm un icati on. We suggest n ext steps for investigating call structure in harbor seal pups and propose comparative hypotheses to test in other pinniped species.
