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Search Results: 1 - 10 of 467668 matches for " Jaime A Pineda "
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Sensorimotor cortex as a critical component of an 'extended' mirror neuron system: Does it solve the development, correspondence, and control problems in mirroring?
Jaime A Pineda
Behavioral and Brain Functions , 2008, DOI: 10.1186/1744-9081-4-47
Abstract: Human beings are social creatures to the extent that interactions with members of their own species, and especially the ability to understand and infer the intentions and beliefs of others, has become of predominant importance in their daily life. Whether for cooperation or non-cooperation, a core assumption of this viewpoint is that such social interactions spring from a distinction between self and others. It can be argued that at least two hierarchically-organized, overlapping and interacting neural systems have evolved and developed to manage self-other distinctions and hence social interactions [1]. One system, part of the classic motor system, is more specialized for the preparation and execution of motor actions that are self realized and voluntary, while the other appears to be more involved in capturing and understanding, at a basic and involuntary level, the actions of non-self or others. For our purposes, actions are defined as sequences of movements that together solve a motor problem [2] and that involve at least four levels of behavioral complexity: intention, kinematics, goal-object identity, and the physical consequences of the action [1]. Motor preparation and execution circuitry includes, among others, the premotor cortex, supplementary motor area, sensorimotor cortices, and parts of the inferior parietal cortex. The second system, of which the mirror neuron system (MNS) is part, has been described as the canonical action 'resonance' system in the brain – one that has evolved to utilize or share many of the same circuits involved in motor control [3]. Mirroring or 'shared circuit' systems are assumed to be important for resonating, imitating, and/or simulating the actions of others. Although no consensus exists, a number of researchers have proposed that shared representations of motor actions, or the action understanding properties of this system, may form a foundational cornerstone for higher order social processes, including motor learning, acti
Neurorehabilitation of social dysfunctions: a model-based neurofeedback approach for low and high-functioning autism
Jaime A. Pineda,Elisabeth V. C. Friedrich,Kristen LaMarca
Frontiers in Neuroengineering , 2014, DOI: 10.3389/fneng.2014.00029
Abstract: Autism Spectrum Disorder (ASD) is an increasingly prevalent condition with core deficits in the social domain. Understanding its neuroetiology is critical to providing insights into the relationship between neuroanatomy, physiology and social behaviors, including imitation learning, language, empathy, theory of mind, and even self-awareness. Equally important is the need to find ways to arrest its increasing prevalence and to ameliorate its symptoms. In this review, we highlight neurofeedback studies as viable treatment options for high-functioning as well as low-functioning children with ASD. Lower-functioning groups have the greatest need for diagnosis and treatment, the greatest barrier to communication, and may experience the greatest benefit if a treatment can improve function or prevent progression of the disorder at an early stage. Therefore, we focus on neurofeedback interventions combined with other kinds of behavioral conditioning to induce neuroplastic changes that can address the full spectrum of the autism phenotype.
The Perils of Clumpfind: The Mass Spectrum of Sub-structures in Molecular Clouds
Jaime E. Pineda,Erik W. Rosolowsky,Alyssa A. Goodman
Physics , 2009, DOI: 10.1088/0004-637X/699/2/L134
Abstract: We study the mass spectrum of sub-structures in the Perseus Molecular Cloud Complex traced by 13CO (1-0), finding that $dN/dM\propto M^{-2.4}$ for the standard Clumpfind parameters. This result does not agree with the classical $dN/dM\propto M^{-1.6}$. To understand this discrepancy we study the robustness of the mass spectrum derived using the Clumpfind algorithm. Both 2D and 3D Clumpfind versions are tested, using 850 $\mu$m dust emission and 13CO spectral-line observations of Perseus, respectively. The effect of varying threshold is not important, but varying stepsize produces a different effect for 2D and 3D cases. In the 2D case, where emission is relatively isolated (associated with only the densest peaks in the cloud), the mass spectrum variability is negligible compared to the mass function fit uncertainties. In the 3D case, however, where the 13CO emission traces the bulk of the molecular cloud, the number of clumps and the derived mass spectrum are highly correlated with the stepsize used. The distinction between "2D" and "3D" here is more importantly also a distinction between "sparse" and "crowded" emission. In any "crowded" case, Clumpfind should not be used blindly to derive mass functions. Clumpfind's output in the "crowded" case can still offer a statistical description of emission useful in inter-comparisons, but the clump-list should not be treated as a robust region decomposition suitable to generate a physically-meaningful mass function. We conclude that the 13CO mass spectrum depends on the observations resolution, due to the hierarchical structure of MC.
The COMPLETE Survey of Outflows in Perseus
Hector G. Arce,Michelle A. Borkin,Alyssa A. Goodman,Jaime E. Pineda,Michael W. Halle
Physics , 2010, DOI: 10.1088/0004-637X/715/2/1170
Abstract: We present a study on the impact of molecular outflows in the Perseus molecular cloud complex using the COMPLETE survey large-scale 12CO(1-0) and 13CO(1-0) maps. We used three-dimensional isosurface models generated in RA-DEC-Velocity space to visualize the maps. This rendering of the molecular line data allowed for a rapid and efficient way to search for molecular outflows over a large (~ 16 sq. deg.) area. Our outflow-searching technique detected previously known molecular outflows as well as new candidate outflows. Most of these new outflow-related high-velocity features lie in regions that have been poorly studied before. These new outflow candidates more than double the amount of outflow mass, momentum, and kinetic energy in the Perseus cloud complex. Our results indicate that outflows have significant impact on the environment immediately surrounding localized regions of active star formation, but lack the energy needed to feed the observed turbulence in the entire Perseus complex. This implies that other energy sources, in addition to protostellar outflows, are responsible for turbulence on a global cloud scale in Perseus. We studied the impact of outflows in six regions with active star formation within Perseus of sizes in the range of 1 to 4 pc. We find that outflows have enough power to maintain the turbulence in these regions and enough momentum to disperse and unbind some mass from them. We found no correlation between outflow strength and star formation efficiency for the six different regions we studied, contrary to results of recent numerical simulations. The low fraction of gas that potentially could be ejected due to outflows suggests that additional mechanisms other than cloud dispersal by outflows are needed to explain low star formation efficiencies in clusters.
A Bubbling Nearby Molecular Cloud: COMPLETE Shells in Perseus
Hector G. Arce,Michelle A. Borkin,Alyssa A. Goodman,Jaime E. Pineda,Christopher N. Beaumont
Physics , 2011, DOI: 10.1088/0004-637X/742/2/105
Abstract: We present a study on the shells (and bubbles) in the Perseus molecular cloud using the COMPLETE survey large-scale 12CO(1-0) and 13CO(1-0) maps. The twelve shells reported here are spread throughout most of the Perseus cloud and have circular or arc-like morphologies with a range in radius of about 0.1 to 3 pc. Most of them have not been detected before most likely as maps of the region lacked the coverage and resolution needed to distinguish them. The majority of the shells are coincident with infrared nebulosity of similar shape and have a candidate powering source near the center. We suggest they are formed by the interaction of spherical or very wide-angle winds powered by young stars inside or near the Perseus molecular cloud -a cloud that is commonly considered to be mostly forming low-mass stars. Two of the twelve shells are powered by high-mass stars close to the cloud, while the others appear to be powered by low or intermediate mass stars in the cloud. We argue that winds with a mass loss rate of about 10^-8 to 10^-6 M_sun/yr are required to produce the observed shells. Our estimates indicate that the energy input rate from these stellar winds is similar to the turbulence dissipation rate. We conclude that in Perseus the total energy input from both collimated protostellar outflows and powerful spherical winds from young stars is sufficient to maintain the turbulence in the molecular cloud. Large scale molecular line and IR continuum maps of a sample of clouds will help determine the frequency of this phenomenon in other star forming regions.
Men and Women Exhibit a Differential Bias for Processing Movement versus Objects
Robert F. McGivern, Brian Adams, Robert J. Handa, Jaime A. Pineda
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032238
Abstract: Sex differences in many spatial and verbal tasks appear to reflect an inherent low-level processing bias for movement in males and objects in females. We explored this potential movement/object bias in men and women using a computer task that measured targeting performance and/or color recognition. The targeting task showed a ball moving vertically towards a horizontal line. Before reaching the line, the ball disappeared behind a masking screen, requiring the participant to imagine the movement vector and identify the intersection point. For the color recognition task, the ball briefly changed color before disappearing beneath the mask and participants were required only to identify the color shade. Results showed that targeting accuracy for slow and fast moving balls was significantly better in males compared to females. No sex difference was observed for color shade recognition. We also studied a third, dual attention task comprised of the first two, where the moving ball briefly changed color randomly just before passing beneath the masking screen. When the ball changed color, participants were required only to identify the color shade. If the ball didn't change color, participants estimated the intersection point. Participants in this dual attention condition were first tested with the targeting and color tasks alone and showed results that were similar to the previous groups tested on a single task. However, under the dual attention condition, male accuracy in targeting, as well as color shade recognition, declined significantly compared to their performance when the tasks were tested alone. No significant changes were found in female performance. Finally, reaction times for targeting and color choices in both sexes correlated highly with ball speed, but not accuracy. Overall, these results provide evidence of a sex-related bias in processing objects versus movement, which may reflect sex differences in bottom up versus top-down analytical strategies.
Aplicación y evaluación de materiales educativos para la prevención del dengue en una institución educativa de Medellín, Colombia
CES Medicina , 2011,
Abstract: introduction: in the absence of an effective vaccine to prevent dengue, it is necessary to implement educational strategies for vector control. objective: to evaluate the efficacy of using educative materials for instruction and learning about dengue. methods: a quasi experimental pre/post design was performed. the study population was 66 children of an educational institution in medellin. the selection of the school and the study population was for convenience. the educational strategies consisted of watching the video game "el invitado mortal", and develop a "juego de parqués sobre dengue". the data collection before and after intervention included knowledge and practice tests for schoolchildren. results: it was observed after the intervention, an statistically significant increase in knowledge of the students in the following variables related to symptoms of fever (56.1% vs. 95.4 % p < 0.001), headache (6.1 % vs. 27.7 %, p < 0.003) and myalgia (12.1 % vs. 61.5 %, p < 0.001), mode of transmission (68.2 % vs. 95.4 %, p = 0.001) and the preventive measure "elimination of breeding sites" (65. 2 % vs. 86.2 %, p = 0.015). it was obvious even before the intervention, the disease management should be in health institutions (90.0 % vs. 100 %, p < 0.001). over 95 % of students reported acceptance of video and game. conclusions: these results suggest that the game as an educational medium is an important tool in understanding the concepts, besides being a participatory activity and satisfactory. therefore could be used in prevention and control programs.
Effective Population Size, Genetic Variation, and Their Relevance for Conservation: The Bighorn Sheep in Tiburon Island and Comparisons with Managed Artiodactyls
Jaime Gasca-Pineda, Ivonne Cassaigne, Rogelio A. Alonso, Luis E. Eguiarte
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0078120
Abstract: The amount of genetic diversity in a finite biological population mostly depends on the interactions among evolutionary forces and the effective population size (Ne) as well as the time since population establishment. Because the Ne estimation helps to explore population demographic history, and allows one to predict the behavior of genetic diversity through time, Ne is a key parameter for the genetic management of small and isolated populations. Here, we explored an Ne-based approach using a bighorn sheep population on Tiburon Island, Mexico (TI) as a model. We estimated the current (Ncrnt) and ancestral stable (Nstbl) inbreeding effective population sizes as well as summary statistics to assess genetic diversity and the demographic scenarios that could explain such diversity. Then, we evaluated the feasibility of using TI as a source population for reintroduction programs. We also included data from other bighorn sheep and artiodactyl populations in the analysis to compare their inbreeding effective size estimates. The TI population showed high levels of genetic diversity with respect to other managed populations. However, our analysis suggested that TI has been under a genetic bottleneck, indicating that using individuals from this population as the only source for reintroduction could lead to a severe genetic diversity reduction. Analyses of the published data did not show a strict correlation between HE and Ncrnt estimates. Moreover, we detected that ancient anthropogenic and climatic pressures affected all studied populations. We conclude that the estimation of Ncrnt and Nstbl are informative genetic diversity estimators and should be used in addition to summary statistics for conservation and population management planning.
Interaction of BCI with the underlying neurological conditions in patients: pros and cons
Aleksandra Vuckovic,Jaime A. Pineda,Kristen LaMarca,Disha Gupta,Christoph Guger
Frontiers in Neuroengineering , 2014, DOI: 10.3389/fneng.2014.00042
The Angular Momentum of Magnetized Molecular Cloud Cores: A 2D-3D Comparison
Sami Dib,Patrick Hennebelle,Jaime E. Pineda,Timea Csengeri,Sylvain Bontemps,Edouard Audit,Alyssa A. Goodman
Physics , 2010, DOI: 10.1088/0004-637X/723/1/425
Abstract: We study the rotational properties of magnetized and self-gravitating molecular cloud cores formed in 2 very high resolution 3D molecular cloud simulations.The simulations have been performed using the code RAMSES at an effective resolution of 4096^3.One simulation represents a mildly magnetically-supercritical cloud and the other a strongly magnetically-supercritical cloud.A noticeable difference between the 2 simulations is the core formation efficiency (CFE) of the high density cores.In the strongly supercritical simulations the CFE is ~33 % per free-fall time of the cloud tff,cl, whereas in the mildly supercritical simulations this value goes down to ~6%/tff,cl. A comparison of the intrinsic specific angular momentum j3D distributions of the cores with the distribitions of j2D derived using synthetic 2D velocity maps of the cores,shows that the synthetic observations tend to overestimate the true value of j by a factor of ~10.The origin of this discrepancy lies in the fact that contrary to the intrinsic determination which sums up the individual gas parcels contributions to j, the determination of j using the observational procedure which is based on a measurement on the global velocity gradient under the hypothesis of uniform rotation smoothes out the complex fluctuations present in the 3D velocity field. Our results provide a natural explanation for the discrepancy by a factor ~10 observed between the intrinsic 3D distributions of j and the corresponding distributions derived in real observations.We suggest that measurements of j which are based on the measurement of the observed global velocity gradients may need to be reduced by a factor of ~10 in order to derive a more accurate estimate of j in the cores.
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