2,844 research outputs found
Forever young(er): potential age-defying effects of long-term meditation on gray matter atrophy
While overall life expectancy has been increasing, the human brain still begins deteriorating after the first two decades of life and continues degrading further with increasing age. Thus, techniques that diminish the negative impact of aging on the brain are desirable. Existing research, although scarce, suggests meditation to be an attractive candidate in the quest for an accessible and inexpensive, efficacious remedy. Here, we examined the link between age and cerebral gray matter re-analyzing a large sample (n = 100) of long-term meditators and control subjects aged between 24 and 77 years. When correlating global and local gray matter with age, we detected negative correlations within both controls and meditators, suggesting a decline over time. However, the slopes of the regression lines were steeper and the correlation coefficients were stronger in controls than in meditators. Moreover, the age-affected brain regions were much more extended in controls than in meditators, with significant group-by-age interactions in numerous clusters throughout the brain. Altogether, these findings seem to suggest less age-related gray matter atrophy in long-term meditation practitioners.Nicolas
Cherbuin is funded by Australian Research Council fellowship number 120100227
Meditation effects within the hippocampal complex revealed by voxel-based morphometry and cytoarchitectonic probabilistic mapping.
Scientific studies addressing anatomical variations in meditators' brains have emerged rapidly over the last few years, where significant links are most frequently reported with respect to gray matter (GM). To advance prior work, this study examined GM characteristics in a large sample of 100 subjects (50 meditators, 50 controls), where meditators have been practicing close to 20 years, on average. A standard, whole-brain voxel-based morphometry approach was applied and revealed significant meditation effects in the vicinity of the hippocampus, showing more GM in meditators than in controls as well as positive correlations with the number of years practiced. However, the hippocampal complex is regionally segregated by architecture, connectivity, and functional relevance. Thus, to establish differential effects within the hippocampal formation (cornu ammonis, fascia dentata, entorhinal cortex, subiculum) as well as the hippocampal-amygdaloid transition area, we utilized refined cytoarchitectonic probabilistic maps of (peri-) hippocampal subsections. Significant meditation effects were observed within the subiculum specifically. Since the subiculum is known to play a key role in stress regulation and meditation is an established form of stress reduction, these GM findings may reflect neuronal preservation in long-term meditators-perhaps due to an attenuated release of stress hormones and decreased neurotoxicity
Information-Theoretic Motion Planning for Constrained Sensor Networks
This paper considers the problem of online informative motion planning for a network of heterogeneous sensing agents, each subject to dynamic constraints, environmental constraints, and sensor limitations. Prior work has not yielded algorithms that are amenable to such general constraint characterizations. In this paper, we propose the Information-rich Rapidly-exploring Random Tree (IRRT) algorithm as a solution to the constrained informative motion planning problem that embeds metrics on uncertainty reduction at both the tree growth and path selection levels. IRRT possesses a number of beneficial properties, chief among them being the ability to find dynamically feasible, informative paths on short timescales, even subject to the aforementioned constraints. The utility of IRRT in efficiently localizing stationary targets is demonstrated in a progression of simulation results with both single-agent and multiagent networks. These results show that IRRT can be used in real-time to generate and execute information-rich paths in tightly constrained environments.AFOSR and USAF under grant (FA9550-08-1-0086
Space shuttle navigation analysis
A detailed analysis of space shuttle navigation for each of the major mission phases is presented. A covariance analysis program for prelaunch IMU calibration and alignment for the orbital flight tests (OFT) is described, and a partial error budget is presented. The ascent, orbital operations and deorbit maneuver study considered GPS-aided inertial navigation in the Phase III GPS (1984+) time frame. The entry and landing study evaluated navigation performance for the OFT baseline system. Detailed error budgets and sensitivity analyses are provided for both the ascent and entry studies
Space shuttle navigation analysis. Volume 2: Baseline system navigation
Studies related to the baseline navigation system for the orbiter are presented. The baseline navigation system studies include a covariance analysis of the Inertial Measurement Unit calibration and alignment procedures, postflight IMU error recovery for the approach and landing phases, on-orbit calibration of IMU instrument biases, and a covariance analysis of entry and prelaunch navigation system performance
Robust Trajectory Planning for Autonomous Parafoils under Wind Uncertainty
A key challenge facing modern airborne delivery systems, such as parafoils, is the ability to accurately and consistently deliver supplies into di cult, complex terrain. Robustness is a primary concern, given that environmental wind disturbances are often highly uncertain and time-varying, coupled with under-actuated dynamics and potentially narrow drop zones. This paper presents a new on-line trajectory planning algorithm that enables a large, autonomous parafoil to robustly execute collision avoidance and precision landing on mapped terrain, even with signi cant wind uncertainties. This algorithm is designed to handle arbitrary initial altitudes, approach geometries, and terrain surfaces, and is robust to wind disturbances which may be highly dynamic throughout the terminal approach. Explicit, real-time wind modeling and classi cation is used to anticipate future disturbances, while a novel uncertainty-sampling technique ensures that robustness to possible future variation is e ciently maintained. The designed cost-to-go function enables selection of partial paths which intelligently trade o between current and reachable future states. Simulation results demonstrate that the proposed algorithm reduces the worst-case impact of wind disturbances relative to state-of-the-art approaches.Charles Stark Draper Laborator
The evolution of octahedral rotations of orthorhombic LaVO3 in superlattices with cubic SrVO3
We have studied the octahedral rotations in LaVO3 SrVO3 superlattices, keeping the thickness of the orthorhombic LaVO3 layers constant and increasing the thickness of cubic SrVO3 layers. We have found that for a small thickness of SrVO3, the octahedral rotations in LaVO3 are maintained, while for an increasing thickness, these rotations are suppressed. This observation cannot be explained by purely elastic effects due to the lattice mismatch between the two materials, but the absence of rotations in SrVO3 is a crucial ingredient, illustrating the concept of interface engineering of octahedral rotation
Sampling-Based Threat Assessment Algorithms for Intersection Collisions Involving Errant Drivers
This paper considers the decision-making problem for a vehicle crossing a road
intersection in the presence of other, potentially errant, drivers. This problem is considered in
a game-theoretic framework, where the errant drivers are assumed to be capable of causing
intentional collisions. Our approach is to simulate the possible behaviors of errant drivers using
RRT-Reach, a modi ed application of rapidly-exploring random trees. A novelty in RRT-Reach
is the use of a dual exploration-pursuit mode, which allows for e cient approximation of the
errant reachability set for some xed time horizon. Through simulation and experimental results
with a small autonomous vehicle, we demonstrate that this threat assessment algorithm can be
used in real-time to minimize the risk of collision
Parasagittal Asymmetries of the Corpus Callosum
Significant relationships have been reported between midsagittal areas of the corpus callosum and the degree of interhemispheric transfer, functional lateralization and structural brain asymmetries. No study, however, has examined whether parasagittal callosal asymmetries (i.e. those close to the midline of the brain), which may be of specific functional consequence, are present in the human brain. Thus, we applied magnetic resonance imaging and novel computational surface-based methods to encode hemispheric differences in callosal thickness at a very high resolution. Discrete callosal areas were also compared between the hemispheres. Furthermore, acknowledging the frequently reported sex differences in callosal morphology, parasagittal callosal asymmetries were examined within each gender. Results showed significant rightward asymmetries of callosal thickness predominantly in the anterior body and anterior third of the callosum, suggesting a more diffuse functional organization of callosal projections in the right hemisphere. Asymmetries were increased in men, supporting the assumption of a sexually dimorphic organization of male and female brains that involves hemispheric relations and is reflected in the organization and distribution of callosal fiber
Diretrizes curriculares nacionais da educação para as relações etnico-raciais e para o ensino da história e cultura afrobrasileira e africana
Material em formato .pdf -- Parte do material do curso de Aperfeiçoamento “A Gestão do Desenvolvimento Inclusivo da Escola” – COMFOR – SEB – SECADI – MINISTÉRIO DA EDUCAÇÃO- Coordenação pedagógica do curso: Coordenadora: Edna Martins / Vice-Coordenadora: Renata Marcílio Candido- Equipe de Produção - SEAD – UNIFESP -- Felipe Vieira Pacheco - Coordenador de Produção / Sandro Takeshi Munakata da Silva - Designer Instrucional / Margeci Leal de Freitas Alves - Designer Instrucional / Fabrício Sawczen - Designer Gráfico• Módulo 5: Diretrizes Curriculares Nacionais da Educação para as Relações Etnicorraciais e para o Ensino da História e Cultura Afrobrasileira e Africana -- Este módulo aborda temas como os Direitos humanos: direito à diversidade nas políticas públicas educacionais, a questão do racismo na pluralidade de suas manifestações e em particular nos processos educacionais, a importância da cultura africana e afrobrasileira na História do Brasil, quilombo: direito ao território e à igualdade etnicorracial, a Convenção nº 169 da OIT, Decreto nº 6040 e Diretrizes Operacionais para uma educação básica do campo e a garantia do direito à educação às comunidades quilombolas, as formas de resistência da cultura negra em uma perspectiva que abrange desde os movimentos sociais até as políticas públicas de ação afirmativa (Leis 10.639 e 11.645) e a história e culturas indígenas.Outr
- …
