1,161 research outputs found

    The Effects of Failure on Self-Esteem and Attributions in Non-Clinical Paranoia

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    The present study used Bentall\u27s attribution model of paranoia to investigate the effects of failure on self-esteem and attribution of those with paranoid symptoms. The present study used individuals who scored high and low on the Paranoia Scale (PS), a measure of paranoia, to form two comparison groups. Each group was given an unsolvable anagram task and told that they performed worse than others. This was used to simulate failure. The study utilized the Rosenberg Self-Esteem Scale (RSES) and the Internal Personal, and Situational Attributions Questionnaire (IPSAQ) to determine what effects failure of the presented task had on their self-esteem and attribution. Data was gathered before and after the failure task and examined to determine what effect failure had on paranoid ideation, self-esteem, and attribution biases in a non-clinical college sample

    Constraining cosmological ultra-large scale structure using numerical relativity

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    Cosmic inflation, a period of accelerated expansion in the early universe, can give rise to large amplitude ultra-large scale inhomogeneities on distance scales comparable to or larger than the observable universe. The cosmic microwave background (CMB) anisotropy on the largest angular scales is sensitive to such inhomogeneities and can be used to constrain the presence of ultra-large scale structure (ULSS). We numerically evolve nonlinear inhomogeneities present at the beginning of inflation in full General Relativity to assess the CMB quadrupole constraint on the amplitude of the initial fluctuations and the size of the observable universe relative to a length scale characterizing the ULSS. To obtain a statistically significant number of simulations, we adopt a toy model in which inhomogeneities are injected along a preferred direction. We compute the likelihood function for the CMB quadrupole including both ULSS and the standard quantum fluctuations produced during inflation. We compute the posterior given the observed CMB quadrupole, finding that when including gravitational nonlinearities, ULSS curvature perturbations of order unity are allowed by the data, even on length scales not too much larger than the size of the observable universe. Our results illustrate the utility and importance of numerical relativity for constraining early universe cosmology.Comment: 14 pages, 6 figures v3: Clarifications added regarding the generality of results - conclusions unchanged, version accepted for publication in PRD, v2: updated with minor clarifications, submitte

    Functional Connectivity in Gait Under Dual-Task Paradigm in Healthy Adolescents

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    PURPOSE: Functional connectivity can be viewed as the mechanism used to coordinate different neural networks in order to perform a complex task. Dual-task walking requires an individual to walk, while simultaneously performing a secondary task. The purpose of this study was to determine the level of functional connectivity and neuro-efficiency in adolescents under the dual-task walking. We hypothesized that we would see an increase in local and global efficiency within adolescents when transitioning from a single task gait test to a dual task gait test. METHODS: 15 healthy adolescents (12 male, age: 16.33±0.94 years, height: 1.69±0.10 m, mass: 64.08±9.81 kg) were recruited. The brain activity of the left and right prefrontal cortex (dorsal lateral, and dorsal media) were measured by fNIRS, the sampling rate of 20.3 Hz. Vicon motion capture system was used to record kinematic data, the sampling rate of 100 Hz. The first test was a single task gait test in which the subject walked at a self-selected speed between two cones 15 meters apart for 2 minutes with 10 seconds of standing as the baseline for fNIRS measures. Subjects were then tested under a dual-task paradigm (serially subtracting 7’s from randomly presented 2 or 3-digit numbers). The primary outcome measures include normalized local and global efficiency, gait speed, and stride length. Two two-way MANOVA with repeated measures were used to examine the task difference (alpha level = 0.05). RESULTS: There was a significant task effect on gait performance (F3,12 = 6.430, p = 0.008). Post hoc pairwise tests indicated that single-task presented greater average walking velocity (p \u3c 0.001, ST vs. DT: 1.33 ± 0.18 vs. 1.23 ± 0.20 m/s) and shorter stride time (p = 0.002, ST vs. DT: 1.11 ± 0.10 vs. 1.14 ± 0.12 s) than dual-task. There was no significant task effect on brain activity and neural efficiency (p \u3e 0.05). CONCLUSION: There was a significant difference in gait speed between adolescents and young adults. This is due to the task complexity affecting adolescents significantly more than adults. Young adults don’t see a change in speed but do see an increase in PFC activation. Adolescents having lower levels of functional connectivity compared to young adults could be due to the number/size of functionally connected regions measured within adolescence. Children are still developing day by day, indicating that the strength of functional connectivity seemingly develops as they age. With this information we can conclude that functional connectivity continuously changes while going through your adolescent years

    Economic differences between cumulative and episodic reduction of sediment from cropland

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    This study compares measures for reducing cumulative sediment loads from cropland with measures for reducing sediment loads from extreme storms. The issue is whether the optimal means of controlling cumulative loads are very different from the optimal controls for storm event loads. Differences are described in terms of costs and management practices. The analysis entailed developing a storm-event simulation model analogous to the SEDEC sedimentation economics model. The analogue model was used to identify the respective optimal cropland management strategies for various extreme storm conditions. These strategies were then analyzed using the annual average SEDEC, and the optimal strategies from SEDEC were analyzed for their storm-event properties. The comparisons permit conclusions concerning the relative effectiveness of management strategies for achieving cumulative sediment goals versus storm-event load goals. Data for a 223 study site in the Highland-Silver Lake Watershed in Southwestern Illinois were analyzed using this approach. The study produced four main conclusions. First, control costs for episodic sediment loads were consistently higher than the costs for proportionate reductions in annual average loads. Furthermore, strategies for reducing cumulative loads generally achieve less than proportionate reductions in cumulative loads. Second, the highest control costs were generally for the most extreme storms. Third, contour cultivation is a key element of efficient management strategies for row crops. Finally, where a permanent grass crop is grown adjacent to the stream, there is generally little more to be gained by changing upslope management practices. This suggests that grass strips along streams would greatly reduce the need to modify farming practices elsewhere in order to limit sedimentation.U.S. Department of the InteriorU.S. Geological SurveyOpe

    Nonlinear dynamics of the cold atom analog false vacuum

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    We investigate the nonlinear dynamics of cold atom systems that can in princi- ple serve as quantum simulators of false vacuum decay. The analog false vacuum manifests as a metastable vacuum state for the relative phase in a two-species Bose-Einstein con- densate (BEC), induced by a driven periodic coupling between the two species. In the appropriate low energy limit, the evolution of the relative phase is approximately governed by a relativistic wave equation exhibiting true and false vacuum configurations. In previous work, a linear stability analysis identified exponentially growing short-wavelength modes driven by the time-dependent coupling. These modes threaten to destabilize the analog false vacuum. Here, we employ numerical simulations of the coupled Gross-Pitaevski equa- tions (GPEs) to determine the non-linear evolution of these linearly unstable modes. We find that unless a physical mechanism modifies the GPE on short length scales, the analog false vacuum is indeed destabilized. We briefly discuss various physically expected correc- tions to the GPEs that may act to remove the exponentially unstable modes. To investigate the resulting dynamics in cases where such a removal mechanism exists, we implement a hard UV cutoff that excludes the unstable modes as a simple model for these corrections. We use this to study the range of phenomena arising from such a system. In particular, we show that by modulating the strength of the time-dependent coupling, it is possible to observe the crossover between a second and first order phase transition out of the false vacuum

    Mass renormalization in lattice simulations of false vacuum decay

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    False vacuum decay, a quantum mechanical first-order phase transition in scalar field theories, is an important phenomenon in early Universe cosmology. Recently, real-time semiclassical techniques based on ensembles of lattice simulations were applied to the problem of false vacuum decay. In this context, or any other lattice simulation, the effective potential experienced by long-wavelength modes is not the same as the bare potential. To make quantitative predictions using the real-time semiclassical techniques, it is therefore necessary to understand the redefinition of model parameters and the corresponding deformation of the vacuum state, as well as stochastic contributions that require modeling of unresolved subgrid modes. In this work, we focus on the former corrections and compute the expected modification of the true and false vacuum effective mass, which manifests as a modified dispersion relationship for linear fluctuations about the vacuum. We compare these theoretical predictions to numerical simulations and find excellent agreement. Motivated by this, we use the effective masses to fix the shape of a parametrized effective potential, and explore the modeling uncertainty associated with nonlinear corrections. We compute the decay rates in both the Euclidean and real-time formalisms, finding qualitative agreement in the dependence on the UV cutoff. These calculations further demonstrate that a quantitative understanding of the rates requires additional corrections

    Efficient Algorithm for Nonpoint Source Pollution Control Problems

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    A dynamic programming algorithm is proposed for a class of nonpoint source pollution control problems. The inherently combinatorial nature of these problems--stemming from the discrete nature of the decision variables, which are production and conservation practices--gives them a special knapsack structure with multiple right hand sides and additional multiple choice constraints. This paper focuses on the computer implementation of this algorithm and its numerical testing and behavior compared with standard integer programming codes. The results show the robustness and relative efficiency of the approach. Furthermore, this paper demonstrates that dynamic programming can be used to generate sensitivity analysis information for multiple choice knapsack problems
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