Opposite Task Research Articles

No evidence for top-down expertise effects on action perception in sprinters using static images

Athletes have been found to demonstrate a superior ability to detect subtle variations in dynamic displays (e.g., point-light displays and videos) depicting expert actions compared to non-athletes. The current study aimed to determine whether this advantage also exists when dynamic information is unavailable (i.e., using static images). Using a staircase procedure, two frames from a video depicting an athlete either walking (everyday action) or performing a sprint start (expert action) were presented, and athletes (sprinters) and non-athletes were asked to indicate whether the images were identical or different. We examined whether presenting the images sequentially (temporal task) or simultaneously (spatial task) influenced participants' discrimination performance. We predicted that the sprinters would outperform the non-sprinters in the spatial task as body postures could be compared directly but not in the temporal task due to larger representational momentum effects for athletes. Contrary to our hypotheses, the sprinters and non-sprinters performed similarly in all tasks and conditions. In line with the prediction that representational momentum may impair performance, participants’ thresholds were lower for the spatial than the temporal task. However, post-hoc analysis suggested that this effect is likely to be better explained by a task order effect whereby participants who completed the temporal task first exhibited an advantage in the spatial task, while there were no performance differences for participants who completed the opposite task order. In sum, our results provide no evidence for the idea that motor expertise affects action perception (i.e., perceptual resonance) in a simple psychophysical task employing static images.

Spatial Response Discrimination May Elicit a Simon Effect on a Non-Complementary Task.

When paired participants are each assigned a complementary half of the Simon task, a joint Simon effect (JSE) has been observed. Co-representation, a cognitive representation of not only one's own task but also that of the co-actor, has been one of several proposed mechanisms in the JSE. Using the response-discrimination hypothesis as a framework, we tested whether it was sufficient to highlight alternative task keys in a two-person setting in which a non-complementary task was completed to elicit a Simon effect (SE). In our design, the participant's role was to perform the Go/No-Go Simon task and the co-actor's role was to initiate each trial for the participant. In one two-person setting participant group (SK group), the same task key was assigned to both the participant and the co-actor; another group (OK) was assigned spatially opposite task keys. In a third group (joint setting, TS group), the standard joint Simon task was also completed to verify that a JSE could be replicated. We hypothesized that an SE would be elicited in the OK group, since opposite task keys would uniquely promote spatial coding. We found a weak but marginally significant SE in the OK group but not in the SK group. These results suggest that, on a non-complementary task, response discrimination may contribute to the emergence of a SE in a two-person setting, while it does not have the same impact as a complementary task completed in a joint setting (TS group) that may afford more robust response representations that reveal the enhanced so-called JSE.

Fast amortized multi-point evaluation

The efficient evaluation of multivariate polynomials at many points is an important operation for polynomial system solving. Kedlaya and Umans have recently devised a theoretically efficient algorithm for this task when the coefficients are integers or when they lie in a finite field. In this paper, we assume that the set of points where we need to evaluate is fixed and “sufficiently generic”. Under these restrictions, we present a quasi-optimal algorithm for multi-point evaluation over general fields. We also present a quasi-optimal algorithm for the opposite interpolation task.

The fall of the Constitution’s political insurance: How the Morales regime eliminated the insurance of the 2009 Bolivian Constitution

Abstract Some scholars argue that constitutions may include an insurance that aims to protect the political rights of prospective electoral losers and prevents a dominant ruling coalition from undermining the competitiveness of the political system. Although some insurance scholars have recently paid more attention to the conditions that make an insurance more likely to be effective, the scholarship seeking to identify the limits of the insurance is still scarce. The literature on courts and democratization may help us to understand those limits by exploring successful and failed experiences. In this article, I argue that after constitution-makers agree to including an insurance, the incumbent regime may delay its implementation or, if the insurance is implemented, the regime may employ different political and legal strategies to eliminate it. I identify some of these strategies using examples from the Bolivian constitutional system. I argue that the Bolivian 2009 Constitution included an insurance and that the Evo Morales regime eliminated it with the help of the Constitutional Court. Although insurance theory expects constitutional courts to guarantee key institutional arrangements, the Bolivian experience shows that constitutional courts may in fact execute the opposite task, and that after constitution makers negotiate and approve an insurance, the challenge is to secure its implementation and survival.

Identification of thermal parameters of a building envelope based on the cooling process of a building object

Thermal properties of building envelopes are often described using thermal conductivity or thermal resistance. And the opposite task involves the identification of thermal parameters of building envelopes based on the measurements of their cooling process. In this article, the authors proposed a method of identifying thermal parameters of a building envelope based on cooling measurements, using a multiple regression model for this purpose. To satisfy the research objectives, two basic experiments were carried out. The first experiment was performed in laboratory conditions. The research model was a cube of the dimensions of 1.1 m × 1.1 m × 1.1 m. The second experiment was carried out in semi-real conditions, and the used model was a small house of the dimensions of 6.0 m × 4.15 m × 5.2 m. The measurement results were also used to calibrate numerical models made in the ESP-r program. The research studies have demonstrated that the model can be used to identify thermal parameters of a building envelope. Based on the measurements and simulations, the cooling equations of the object were determined and the 95% confidence interval for the heat retention index was estimated. On that basis, using the multiple regression model, such parameters of the model as density, specific heat, and thermal conductivity were estimated. It turned out that using the Gauss–Newton approximation, we obtained the correlation of the measurement results and the analytical model with the correlation coefficient of 0.9971 (for the laboratory scale). And the multiple regression improved not only the correlation between the measurement and the analytical model, but it also allowed to obtain “almost identical” results. Similarly, promising results were obtained for the semi-real scale.

Spatial Cues Influence Time Estimations in Deaf Individuals.

SummaryRecent studies have reported a strong interaction between spatial and temporal representation when visual experience is missing: blind people use temporal representation of events to represent spatial metrics. Given the superiority of audition on time perception, we hypothesized that when audition is not available complex temporal representations could be impaired, and spatial representation of events could be used to build temporal metrics. To test this hypothesis, deaf and hearing subjects were tested with a visual temporal task where conflicting and not conflicting spatiotemporal information was delivered. As predicted, we observed a strong deficit of deaf participants when only temporal cues were useful and space was uninformative with respect to time. However, the deficit disappeared when coherent spatiotemporal cues were presented and increased for conflicting spatiotemporal stimuli. These results highlight that spatial cues influence time estimations in deaf participants, suggesting that deaf individuals use spatial information to infer temporal environmental coordinates.

Multisensory Interference in Early Deaf Adults

Multisensory interactions in deaf cognition are largely unexplored. Unisensory studies suggest that behavioral/neural changes may be more prominent for visual compared to tactile processing in early deaf adults. Here we test whether such an asymmetry results in increased saliency of vision over touch during visuo-tactile interactions. About 23 early deaf and 25 hearing adults performed two consecutive visuo-tactile spatial interference tasks. Participants responded either to the elevation of the tactile target while ignoring a concurrent visual distractor at central or peripheral locations (respond to touch/ignore vision), or they performed the opposite task (respond to vision/ignore touch). Multisensory spatial interference emerged in both tasks for both groups. Crucially, deaf participants showed increased interference compared to hearing adults when they attempted to respond to tactile targets and ignore visual distractors, with enhanced difficulties with ipsilateral visual distractors. Analyses on task-order revealed that in deaf adults, interference of visual distractors on tactile targets was much stronger when this task followed the task in which vision was behaviorally relevant (respond to vision/ignore touch). These novel results suggest that behavioral/neural changes related to early deafness determine enhanced visual dominance during visuo-tactile multisensory conflict.

Automatic Retrieval of Newly Instructed Cue-Task Associations Seen in Task-Conflict Effects in the First Trial after Cue-Task Instructions.

Novel stimulus-response associations are retrieved automatically even without prior practice. Is this true for novel cue-task associations? The experiment involved miniblocks comprising three phases and task switching. In the INSTRUCTION phase, two new stimuli (or familiar cues) were arbitrarily assigned as cues for up-down/right-left tasks performed on placeholder locations. In the UNIVALENT phase, there was no task cue since placeholder's location afforded one task but the placeholders were the stimuli that we assigned as task cues for the following BIVALENT phase (involving target locations affording both tasks). Thus, participants held the novel cue-task associations in memory while executing the UNIVALENT phase. Results show poorer performance in the first univalent trial when the placeholder was associated with the opposite task (incompatible) than when it was compatible, an effect that was numerically larger with newly instructed cues than with familiar cues. These results indicate automatic retrieval of newly instructed cue-task associations.

When Do Children Understand “Opposite”?

The aims of the present research were to determine (a) the age at which children with typical development understand the concept of opposite, (b) whether this is related to other cognitive abilities or experiences, and (c) whether there is early implicit understanding of the concept. Children (N = 204) between 3 and 5 years of age were randomly assigned to 1 of 3 experimental conditions in a novel opposite task. Children's language and working memory skills were assessed, and parents provided information about children's access to learning materials about opposites. In the opposite task, 4- and 5-year-olds, but not 3-year-olds, demonstrated acquisition of the concept of opposite. Children demonstrated this understanding only when asked for the "opposite" one, suggesting that antonymy was not made salient by stimulus properties alone. Children's accuracy was not significantly related to their language or working memory skills, to their child care experience, or to whether parents reported having books or games about opposites or playing opposite word games with children. Eye gaze analyses provided no evidence for early implicit understanding of the concept of opposite. Children with typical development have a concept of opposite by 4 years of age.

Three-dimensional (3D) simulation versus two-dimensional (2D) enhances surgical skills acquisition in standardised laparoscopic tasks: A before and after study

IntroductionThe aim of this study is to determine if simulated 3D vision improves the speed and accuracy of laparoscopic phantom tasks in laparoscopically naïve subjects. MethodsThirty laparoscopically naïve subjects were divided into matched groups according to age, sex, hand dominance and initial scores on a standardised visio-spatial test. Laprotrain© laparoscopic simulators were used, one attached to the standard 2D monitor and the other to a simulated 3D monitor and 3D glasses were worn by the subjects in this group. Five standardised laparoscopic tasks were developed and the subjects underwent testing on four separate occasions with more than 24 h between sessions. The subjects were timed for each task and errors were recorded by two independent observers. In the second part of the study, subjects switched to the opposite group and task times and errors were again recorded. Statistical differences between groups were calculated using student t-test and Fisher's exact test. ResultsThere were fifteen subjects in each group with no significant difference in demographic or psychometric variables. The mean time to complete the tasks was faster in the 3D group compared with the 2D group. There was a lower rate of errors noted in the 3D group compared with the 2D group but this only reached statistical significance in two of the five laparoscopic tasks. In the crossover study, subjects who had trained on simulated 3D had better task times and fewer errors compared to those who had trained on 2D simulators. Discussion & conclusionTraining on a simulated 3D model (compared to standard 2D) allows trainees to reach proficiency sooner.

A Low-Noise DC seismic accelerometer based on a combination of MET/MEMS sensors.

Molecular-electronic transducers (MET) have a high conversion coefficient and low power consumption, and do not require precision mechanical components thus allowing the construction of cost- and power-efficient seismic accelerometers. Whereas the instrumental resolution of a MET accelerometer within the 0.1–100 Hz frequency range surpasses that of the best Micro-Electro Mechanical Systems (MEMS) and even some force-balanced accelerometers, the fundamental inability to register gravity or, in other words, zero frequency acceleration, significantly constrains the further spread of MET-based accelerometers. Ways of obviating this inherent zero frequency insensitivity within MET technology have so far, not been found. This article explores a possible approach to the construction of a hybrid seismic accelerometer combining the superb performance of a MET sensor in the middle and high frequency range with a conventional on chip MEMS accelerometer covering the lower frequencies and gravity. Though the frequency separation of a signal is widely used in various applications, the opposite task, i.e., the combining of two signals with different bandwidths is less common. Based on theoretical research and the analysis of actual sensors' performance, the authors determined optimal parameters for building a hybrid sensor. Description and results for implementation of the hybrid sensor are given in the Experimental section of the article. Completing a MET sensor with a cost-effective MEMS permitted the construction of a low noise DC accelerometer preserving the noise performance of a MET sensing element. The work presented herein may prove useful in designing other combined sensors based on different technologies.

Word Mapping and Executive Functioning in Young Monolingual and Bilingual Children

The effect of bilingualism on the cognitive skills of young children was investigated by comparing performance of 162 children who belonged to one of two age groups (approximately 3- and 4.5-year-olds) and one of three language groups on a series of tasks examining executive control and word mapping. The children were monolingual English speakers, monolingual French speakers, or bilinguals who spoke English and one of a large number of other languages. Monolinguals obtained higher scores than bilinguals on a receptive vocabulary test and were more likely to demonstrate the mutual exclusivity constraint, especially at the younger ages. However, bilinguals obtained higher scores than both groups of monolinguals on three tests of executive functioning: Luria's tapping task measuring response inhibition, the opposite worlds task requiring children to assign incongruent labels to a sequence of animal pictures, and reverse categorization in which children needed to reclassify a set of objects into incongruent categories after an initial classification. There were no differences between the groups in the attentional networks flanker task requiring executive control to ignore a misleading cue. This evidence for a bilingual advantage in aspects of executive functioning at an earlier age than previously reported is discussed in terms of the possibility that bilingual language production may not be the only source of these developmental effects.

Error analysis of proper motions in decination obtained for 807 Hipparcos stars from PZT observations over many decades

AbstractAfter publication of the Hipparcos catalogue (in 1997), a few new astrometric catalogues have appeared (TYCHO‐2, ARIHIP, etc.), as a good combination of the Hipparcos satellite and ground‐based data, to get more accurate coordinates and proper motions of stars than the Hipparcos catalogue ones. There are also investigations on improving the Hipparcos coordinates and proper motions by using the astrometric observations of latitude and universal time variations (via observed stars referred to Hipparcos catalogue), together with Hipparcos data, carried out during the last few years. These kind of ground‐based data were collected at the end of the last century by J. Vondrák. There are about 4.4 million optical observations made worldwide at 33 observatories and with 47 instruments during 1899.7–1992.0; our Belgrade visual zenith telescope data (for the period 1949.0‐1986.0) were included. First of all, these data were used to determine the Earth Orientation Parameters – EOP, but they are also useful for the opposite task – to check the accuracy of coordinates and proper motions of Hipparcos stars which were observed from the ground over many decades. Here, we use the latitude part of ten Photographic Zenith Tubes – PZT data (more than 0.9 million observations made at 6 observatories during the time interval 1915.8–1992.0), and combine them with the Hipparcos catalogue ones, with suitable weights, in order to check the proper motions in declination for 807 common PZT/Hipparcos stars (and to construct the PZT catalogue of μδ for 807 stars). Our standard errors in proper motions in declination of these stars are less than or equal to the Hipparcos ones for 423 stars. The mean value of standard errors of 313 stars observed over more than 20 years by PZT is 0.40 mas/yr. This is 53% of 0.75 mas/yr (the suitable value from the Hipparcos catalogue). We used the Least Squares Method – LSM with the linear model. Our results are in good agreement with the Earth Orientation Catalogue – EOC‐2 and the new Hipparcos ones. The main steps of the method and the investigations of systematic errors in determined proper motions (the proper motion differences with respect to the Hipparcos values, the EOC‐2 ones and the new Hipparcos ones, as a function of α, δ, and magnitude) are presented here. A comparison of the four catalogues by pairs shows that there is no significant relationship between the differences of their μδ values and magnitudes and color indices of the common 807 stars. All catalogues have relatively small random and systematic errors which are close to each other. However, the comparison shows that our formal errors are too small. They are underestimated by a factor of nearly 1.7 (for EOC‐2, it is 2.0) if we take the new Hipparcos (or Hipparcos) data as reference (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Childhood Obesity and Impulsivity: An Investigation With Performance-Based Measures

AbstractThe study investigated whether obese children are more impulsive than lean children, taking into account the multidimensionality of the construct. Responses of 41 overweight children were compared to those of 40 lean children. The Stop Task, Circle Drawing Task and Opposite Worlds Task were administered to measure executive inhibitory control, and the Maudsley Index of Childhood Delay Aversion and the Door Opening Task were administered to measure motivational inhibitory control. On the Stop Task, the overweight children showed less inhibitory control. On the Opposite Worlds task, we found no significant difference, whereas on the Circle Drawing Task an unexpected group difference was found. Although on the Door Opening Task the overweight children showed greater reward sensitivity, they were equally motivated to wait on the Maudsley Index of Childhood Delay. We conclude that the findings were different depending on the measure used, but that they suggest that overweight children can be characterised by a decrease in executive and motivational inhibitory control.

Exploring the link between impulsivity and peer relations in 5‐ and 6‐year‐old children

In recent years there has been an increased interest in the behavioural correlates of poor peer relations in childhood. It is now apparent that early poor peer relations are associated with negative future outcomes. The present study investigated whether behaviours that reflect impulsivity or require response inhibition are uniquely linked to children's peer relations. Five- and 6-year-old children's impulsivity was assessed using the teacher-rated impulsivity scale (TRIS), while the stop signal task and a modified version of Manly et al.'s opposite worlds task were employed as measures of response inhibition. In addition, peer relations measures were obtained for each child by asking their peers to indicate on a peer rating scale how much they would like to play with them. It was found that children's scores on the TRIS correlated significantly with peer relations measures (sociometric preference, peer acceptance and peer rejection) after controlling for gender, age and intelligence. Children rated by their teachers to be more impulsive had poorer peer relations. While there was a significant correlation between TRIS and stop-signal task performance, little relationship was found between either of the response inhibition measures and children's peer relations. The findings indicate that impulsivity is associated with children's poor relations with their peers and that this association is dependent upon the measure of impulsivity used. Whereas the more subjective teacher-ratings of impulsiveness did correlate with peer relations, the more objective behavioural measures of response inhibition, (thought to directly measure impulsivity), did not. The difference between these measures needs further investigation. While the data are correlational and causal direction can only be speculated, a practical implication of the finding of an association between impulsivity and peer acceptance is that adoption of strategies to minimize impulsive behaviour may improve the poor peer relations of children.

Camera navigation and tissue manipulation; are these laparoscopic skills related?

It is a tacit assumption that clinically based expertise in laparoscopic tissue manipulation entails skilfulness in angled laparoscope navigation. The main objective of this study was to investigate the relation between these skills. To this end, face and construct validity had to be established for the place arrow (PA) and camera navigation (CN) tasks on the SimSurgery SEP. Thirty-three novices (no laparoscopy experience) and 33 experienced participants (>50 laparoscopic procedures and familiar with angled laparoscopy) performed both tasks twice, on one of two hardware platforms (SimSurgery SimPack or Xitact/Mentice IHP), and rated the realism and didactic value of SimSurgery SEP on five-point scales. Both tasks were rated by the experienced participants as realistic (CN: 3.7; PA: 4.1) and SimSurgery SEP as a user-friendly environment to train basic skills (4.1). Both tasks were performed in less time by the experienced group, with shorter tip trajectories. For both groups jointly, the time to accomplish each task correlated with the tip trajectory and also with the time and tip trajectories of the opposite task (Spearman's correlation, p <or= 0.05). Within the groups however, the performances on both tasks did not always correlate. A correlation was not always found between the performances on the two tasks, which suggests that clinically based expertise in tissue manipulation does not automatically entail skilfulness in angled laparoscope navigation, and vice versa. Training and assessment of basic laparoscopic skills should focus on these tasks independently. More research is needed to better identify the skills and required proficiency levels for different laparoscopic tasks.

O1-04-06: Glycogen synthase kinase-3β and the p25 activator of cyclin-dependent kinase-5 regulate axoplasmic transport of mitochondria by increasing their stationary behavior

testing, a lithium chow diet was used. We also assessed the effect of the lithium diet on LTP of pyramidal cells in area CA1 of hippocampal slices, an area strongly implicated in the pathophysiology of Alzheimer’s disease. Socially housed rats were given continual access to lithium chow or to a control chow diet for four weeks prior to, and throughout all learning assessments. After four weeks access to their designated chow diet, rats began conditioning in the holeboard spatial discrimination or t-maze delayed alternation task. They immediately began conditioning in the opposite task once completing the first. This was then followed with social place-preference conditioning, after 24-hours isolation from their homecage social partner. Results: Results showed that chronic lithium magnified learning in all three paradigms, regardless of the reward received. Both food and social interaction supported enhanced learning. Furthermore, four weeks exposure to the lithium diet also enhanced LTP in area CA1 of hippocampal slices prepared from the rats fed with the lithium chow. This enhancement was shown under clinically relevant serum levels at the time of testing (0.70 0.03 mEq/l). Conclusions: These findings suggest that chronic lithium treatment may improve cognitive function in Alzheimer’s disease by enhancing mechanisms involved in basal learning and memory formation, such as hippocampal LTP.

Analysis of quantum semigroups with GKS–Lindblad generators: I. Simple generators

Semigroups describing the time evolution of open quantum systems in finite-dimensional spaces have generators of a special form, known as Lindblad generators. The simple generators, characterized by only one operator, are analyzed. The complete set of all the stationary states is presented in detail, including a formula to calculate a stationary state from the generating operator. Also the opposite task can be fulfilled, to construct an evolution leading to a prescribed stationary state.

Chronic lithium treatment magnifies learning in rats

Recent electrophysiological work shows that chronic lithium treatment increases long-term potentiation (LTP) in neurons of the hippocampus, and LTP is thought to be the major neurophysiological basis for the development of learning and memory. This suggests that lithium might enhance learning and memory. Available studies have mainly assessed memory using aversive conditioning paradigms, but very little is available on the effect of lithium on learning. Since lithium may diminish anxiety or negative affect in adult rats, which would hinder aversive learning, the present study used three different positive reinforcement spatial cognitive tasks to determine whether chronic lithium affects learning. Each task differed in complexity, in the type of learning required, and in the reward received. For 4 weeks prior to, and throughout all learning assessments, rats had continual access to lithium chow or to a control chow diet. After 4 weeks’ access to their designated chow diet, rats began conditioning in the hole-board spatial discrimination or T-maze delayed alternation tasks in a counterbalanced fashion. They immediately began conditioning in the opposite task once completing the first. This was then followed with social place-preference conditioning, after 24-h isolation from their home-cage social partner. Chronic lithium increased learning in all three paradigms, regardless of the reward received. Indeed, both food and social interaction supported enhanced learning. Thus the learning effect was not merely due to an effect of lithium on food palatability. Importantly, clinically relevant serum lithium levels were evidenced at the time of testing. Lithium also marginally enhanced memory as well. Thus chronic lithium treatment may improve learning and memory in Alzheimer’s disease, and do so not only by blocking the formation of beta-amyloid and neurofibrillary tangles as suggested by previous research, but also by enhancing mechanisms involved in basal learning and memory formation, such as hippocampal synaptic plasticity.

Neurons in Area V4 of the Macaque Translate Attended Visual Features into Behaviorally Relevant Categories

Neural processing at most stages of the primate visual system is modulated by selective attention, such that behaviorally relevant information is emphasized at the expenses of irrelevant, potentially distracting information. The form of attention best understood at the cellular level is when stimuli at a given location in the visual field must be selected (space-based attention). In contrast, fewer single-unit recording studies have so far explored the cellular mechanisms of attention operating on individual stimulus features, specifically when one feature (e.g., color) of an object must guide behavioral responses while a second feature (e.g., shape) of the same object is potentially interfering and therefore must be ignored. Here we show that activity of neurons in macaque area V4 can underlie the selection of elemental object features and their "translation" into a categorical format that can directly contribute to the control of the animal's behavior.