1,426 research outputs found
Introduction to the Developmental Contextualism Surrounding Identity Vulnerability and the Emergence of Depression and Anxiety
According to Cicchetti and Toth (1998), the integration of inadequate biological, ecological, socioemotional, cognitive, and self-representational forces may foster psychopathological organization. These forces comprise developmental contextualism. Contextualism can be visualized as a bidirectional relationship between the individual and the context (Lemer, 2002). In other words, internal and external forces interact with one another as they are affecting the organism. Ecology, socioemotionality, cognition, and biology interact to form the self-representational sense of self or “other” source. This other source is the subjective experience of the organism and emerges as a force in and of itself and influences superceding interactions between ecology, cognition, socioemotionality, and biology. The self-representational sense of self is an internal experience of the self and is where vulnerability to the outside world develops. Vulnerability is experienced subjectively as having a weak self-structure and being easily triggered by unclear or negative contextual variables. Therefore, it seems reasonable to suggest that security in sense of self, or degree of self-integration may dictate vulnerability to common psychopathology such as depression and anxiety (Dombeck, 1995). In leau of the potential relationship between these variables, this particular study assessed how identity vulnerability, depression, and anxiety related to one another through self-reported measures. There was an indication of comorbidity suggesting that identity vulnerability is an underlying factor in the development and experience of depression and anxiety
Lithium depletion in solar-like stars: effect of overshooting based on realistic multi-dimensional simulations
We study lithium depletion in low-mass and solar-like stars as a function of
time, using a new diffusion coefficient describing extra-mixing taking place at
the bottom of a convective envelope. This new form is motivated by
multi-dimensional fully compressible, time implicit hydrodynamic simulations
performed with the MUSIC code. Intermittent convective mixing at the convective
boundary in a star can be modeled using extreme value theory, a statistical
analysis frequently used for finance, meteorology, and environmental science.
In this letter, we implement this statistical diffusion coefficient in a
one-dimensional stellar evolution code, using parameters calibrated from
multi-dimensional hydrodynamic simulations of a young low-mass star. We propose
a new scenario that can explain observations of the surface abundance of
lithium in the Sun and in clusters covering a wide range of ages, from
50 Myr to 4 Gyr. Because it relies on our physical model of convective
penetration, this scenario has a limited number of assumptions. It can explain
the observed trend between rotation and depletion, based on a single additional
assumption, namely that rotation affects the mixing efficiency at the
convective boundary. We suggest the existence of a threshold in stellar
rotation rate above which rotation strongly prevents the vertical penetration
of plumes and below which rotation has small effects. In addition to providing
a possible explanation for the long standing problem of lithium depletion in
pre-main sequence and main sequence stars, the strength of our scenario is that
its basic assumptions can be tested by future hydrodynamic simulations.Comment: 7 pages, 3 figures, Accepted for publication in ApJ Letter
Interictal infraslow activity in patients with epilepsy
pre-printObjective: To evaluate if interictal infraslow activity (ISA), as obtained from a conventional EEG system, can contribute information about the epileptogenic process. Methods: The entire long-term intracranial monitoring sessions of 12 consecutive patients were evaluated on an XLTEK system for ISA. Three additional patients had long-term scalp recordings. Results: In intracranial as well as scalp recordings, the ISA background was consistently higher in the waking state than during sleep. From this background emerged intermittently focal changes, which could achieve in intracranial recordings millivolt amplitudes, while they remained in the microvolt range in scalp recordings. Although they were mainly contiguous between adjacent channels, this was not necessarily the case and intermittent build-up could be seen distant from the epileptogenic zone or radio-graphic lesion. Conclusions: Interictal ISA can be detected in routine intracranial and scalp recordings, without the need for DC amplifiers, and can provide additional information. Significance: Since ISA is a separate element of the electromagnetic spectrum, apparently non-neuronal in origin, its assessment should be included not only in the pre-surgical evaluation of epilepsy patients but also in patients with other neurologic disorders and normal volunteers
The impact of trade, trade policy and external shocks on the Philippine economy based on the PIDS-NEDA macaroeconometric model
This report analyzes the impact of the external 'sector and
of Some economic policies on the Philippine economy ba'sed on the
reSultS of the simulations Suggested for this year's Model
Comparisons WOrkShop, The Simulation's were done uSing the latest
verSion of the PIDS-NEDA Annual Macroeconometric Model for the
Philippines.
ThiS report alSo deScribe's how the simulation's were carried
out and what adjustments and aSSumptionS were made. To allow a
better appreciation and understanding of the re'sult's, a brief description of the model structure iS presented with particular
emphaSiS on the external 'sector and itS linkages with the real
and financial SectorS.
The baseline Solution and the simulations were done for the
period 1980-1986. No constant adjustments were incorporated and
So the estimated values are not the Same aS the actual values,
although they are reasonably close to each other
Comparison of two- and three-dimensional compressible convection in a pre-main sequence star
Extending our recent studies of two-dimensional stellar convection to 3D, we
compare three-dimensional hydrodynamic simulations to identically set-up
two-dimensional simulations, for a realistic pre-main sequence star. We compare
statistical quantities related to convective flows including: average velocity,
vorticity, local enstrophy, and penetration depth beneath a convection zone.
These statistics are produced during stationary, steady-state compressible
convection in the star's convection zone. Our simulations with the MUSIC code
confirm the common result that two-dimensional simulations of stellar
convection have a higher magnitude of velocity on average than
three-dimensional simulations. Boundary conditions and the extent of the
spherical shell can affect the magnitude and variability of convective
velocities. The difference between 2D and 3D velocities is dependent on these
background points; in our simulations this can have an effect as large as the
difference resulting from the dimensionality of the simulation. Nevertheless,
radial velocities near the convective boundary are comparable in our 2D and 3D
simulations. The average local enstrophy of the flow is lower for
two-dimensional simulations than for three-dimensional simulations, indicating
a different shape and structuring of 3D stellar convection. We perform a
statistical analysis of the depth of convective penetration below the
convection zone, using the model proposed in our recent study (Pratt et al.
2017). Here we analyze the convective penetration in three dimensional
simulations, and compare the results to identically set-up 2D simulations. In
3D the penetration depth is as large as the penetration depth calculated from
2D simulations.Comment: 13 pages, 8 figure
Extreme value statistics for two-dimensional convective penetration in a pre-Main Sequence star
This is the author accepted manuscript. The final version is available from EDP Sciences via the DOI in this record.We examine a penetration layer formed between a central radiative zone and a large convection zone in the deep interior of a young low-mass star. Using the Multidimensional Stellar Implicit Code (MUSIC) to simulate two-dimensional compressible stellar convection in a spherical geometry over long times, we produce statistics that characterize the extent and impact of convective penetration in this layer. We apply extreme value theory to the maximal extent of convective penetration at any time. We compare statistical results from simulations which treat non-local convection, throughout a large portion of the stellar radius, with simulations designed to treat local convection in a small region surrounding the penetration layer. For each of these situations, we compare simulations of different resolution, which have different velocity magnitudes. We also compare statistical results between simulations that radiate energy at a constant rate to those that allow energy to radiate from the stellar surface according to the local surface temperature. Based on the frequency and depth of penetrating convective structures, we observe two distinct layers that form between the convection zone and the stable radiative zone. We show that the probability density function of the maximal depth of convective penetration at any time corresponds closely in space with the radial position where internal waves are excited. We find that the maximal penetration depth can be modeled by a Weibull distribution with a small shape parameter. Using these results, and building on established scalings for diffusion enhanced by large-scale convective motions, we propose a new form for the diffusion coefficient that may be used for one-dimensional stellar evolution calculations in the large P\'eclet number regime. These results should contribute to the 321D link.The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework (FP7/2007-2013)/ERC grant agreement no. 32047
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