6,329 research outputs found
Precis of neuroconstructivism: how the brain constructs cognition
Neuroconstructivism: How the Brain Constructs Cognition proposes a unifying framework for the study of cognitive development that brings together (1) constructivism (which views development as the progressive elaboration of increasingly complex structures), (2) cognitive neuroscience (which aims to understand the neural mechanisms underlying behavior), and (3) computational modeling (which proposes formal and explicit specifications of information processing). The guiding principle of our approach is context dependence, within and (in contrast to Marr [1982]) between levels of organization. We propose that three mechanisms guide the emergence of representations: competition, cooperation, and chronotopy; which themselves allow for two central processes: proactivity and progressive specialization. We suggest that the main outcome of development is partial representations, distributed across distinct functional circuits. This framework is derived by examining development at the level of single neurons, brain systems, and whole organisms. We use the terms encellment, embrainment, and embodiment to describe the higher-level contextual influences that act at each of these levels of organization. To illustrate these mechanisms in operation we provide case studies in early visual perception, infant habituation, phonological development, and object representations in infancy. Three further case studies are concerned with interactions between levels of explanation: social development, atypical development and within that, developmental dyslexia. We conclude that cognitive development arises from a dynamic, contextual change in embodied neural structures leading to partial representations across multiple brain regions and timescales, in response to proactively specified physical and social environment
Is procrastination related to sleep quality? Testing an application of the procrastination-health model
Despite a growing body of research on the consequences of procrastination for health and well-being, there is little research focused on testing or explaining the potential links between procrastination and sleep quality. Using the procrastination-health model as our guiding conceptual lens, we addressed this gap by examining how and why trait procrastination may be linked to various dimensions of sleep quality across two student samples. In Study 1, procrastination was associated with feeling unrested, but not sleep disturbance frequency, in a sample of Greek undergraduate students (N = 141). In Study 2, bootstrapping analysis of the indirect effects of procrastination on an index of sleep quality through perceived stress in a sample of Canadian students (N = 339) was significant supporting an extended procrastination-health model view of how chronic self-regulation failure may compromise sleep quality. Given the potential for dynamic and reciprocal relations among procrastination, stress, and sleep quality suggested by the current and other research, the ways in which procrastination may contribute to and be influenced by poor sleep quality warrants further investigation
Self-compassion and physical health: Exploring the roles of perceived stress and health-promoting behaviors
Growing evidence indicates that self-compassion is associated with better physical health, but the pathways that mediate this relationship are not well understood. This study tested a serial mediation model that linked self-compassion, perceived stress, health behaviors, and a comprehensive index of physical health. A sample of 176 individuals completed an online survey posted on Amazon’s Mechanical Turk. Self-compassion had an indirect effect on physical health via both mediators as well as through the sequential pathway, suggesting that taking a kind, accepting and mindful stance toward one’s flaws and failures may have benefits for reducing stress and promoting health behaviors
Can Frequency Domain Heart Rate Measures Detect Impaired Driver Performance?
An overnight driving simulation scenario with partial sleep deprivation was utilized to induce driver performance impairment. Heart rate (HR) was recorded over the entire experiment; frequency domain HR measures were derived and correlated to variation of lane deviation (VLD), a driving performance measure, and to the driver\u27s state, which was estimated by the Karolinska Sleepiness Scale (KSS). The aim of this study is to evaluate whether frequency domain heart rate measures can be used to detect impaired driver performance as well as reduced driver state. We generalize the concept of the conventional frequency domain HR measures – namely the very-low frequency (VLF), low frequency (LF) band and high frequency (HF) band – into finer-grained frequency bands of 0.02 Hz width. These newly defined frequency bands show a more detailed correlation to driving performance and to driver sleepiness state, taking subjectspecific differences into account
Measurement crosstalk between two phase qubits coupled by a coplanar waveguide
We analyze the measurement crosstalk between two flux-biased phase qubits
coupled by a resonant coplanar waveguide cavity. After the first qubit is
measured, the superconducting phase can undergo damped oscillations resulting
in an a.c. voltage that produces a frequency chirped noise signal whose
frequency crosses that of the cavity. We show experimentally that the coplanar
waveguide cavity acts as a bandpass filter that can significantly reduce the
crosstalk signal seen by the second qubit when its frequency is far from the
cavity's resonant frequency. We present a simple classical description of the
qubit behavior that agrees well with the experimental data. These results
suggest that measurement crosstalk between superconducting phase qubits can be
reduced by use of linear or possibly nonlinear resonant cavities as coupling
elements.Comment: 4 pages, 3 figure
Circuit QED scheme for realization of the Lipkin-Meshkov-Glick model
We propose a scheme in which the Lipkin-Meshkov-Glick model is realized
within a circuit QED system. An array of N superconducting qubits interacts
with a driven cavity mode. In the dispersive regime, the cavity mode is
adiabatically eliminated generating an effective model for the qubits alone.
The characteristic long-range order of the Lipkin-Meshkov-Glick model is here
mediated by the cavity field. For a closed qubit system, the inherent second
order phase transition of the qubits is reflected in the intensity of the
output cavity field. In the broken symmetry phase, the many-body ground state
is highly entangled. Relaxation of the qubits is analyzed within a mean-field
treatment. The second order phase transition is lost, while new bistable
regimes occur.Comment: 5 pages, 2 figure
Studying development in the 21(st) century
In this response, we consider four main issues arising from the commentaries to the target article. These include further details of the theory of interactive specialization, the relationship between neuroconstructivism and selectionism, the implications of neuroconstructivism for the notion of representation, and the role of genetics in theories of development. We conclude by stressing the importance of multidisciplinary approaches in the future study of cognitive development and by identifying the directions in which neuroconstructivism can expand in the Twenty-first Century
Shielding efficiency and E(J) characteristics measured on large melt cast Bi-2212 hollow cylinders in axial magnetic fields
We show that tubes of melt cast Bi-2212 used as current leads for LTS magnets
can also act as efficient magnetic shields. The magnetic screening properties
under an axial DC magnetic field are characterized at several temperatures
below the liquid nitrogen temperature (77 K). Two main shielding properties are
studied and compared with those of Bi-2223, a material that has been considered
in the past for bulk magnetic shields. The first property is related to the
maximum magnetic flux density that can be screened, Blim; it is defined as the
applied magnetic flux density below which the field attenuation measured at the
centre of the shield exceeds 1000. For a cylinder of Bi-2212 with a wall
thickness of 5 mm and a large ratio of length over radius, Blim is evaluated to
1 T at T = 10 K. This value largely exceeds the Blim value measured at the same
temperature on similar tubes of Bi-2223. The second shielding property that is
characterized is the dependence of Blim with respect to variations of the sweep
rate of the applied field, dBapp/dt. This dependence is interpreted in terms of
the power law E = Ec(J/Jc)^n and allows us to determine the exponent n of this
E(J) characteristics for Bi-2212. The characterization of the magnetic field
relaxation involves very small values of the electric field. This gives us the
opportunity to experimentally determine the E(J) law in an unexplored region of
small electric fields. Combining these results with transport and AC shielding
measurements, we construct a piecewise E(J) law that spans over 8 orders of
magnitude of the electric field.Comment: 16 pages, 7 figure
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