80 research outputs found
Light scattering spectra of supercooled molecular liquids
The light scattering spectra of molecular liquids are derived within a
generalized hydrodynamics. The wave vector and scattering angle dependences are
given in the most general case and the change of the spectral features from
liquid to solidlike is discussed without phenomenological model assumptions for
(general) dielectric systems without long-ranged order. Exact microscopic
expressions are derived for the frequency-dependent transport kernels,
generalized thermodynamic derivatives and the background spectra.Comment: 12 page
Sea level and climate changes during OIS 5e in the Western Mediterranean
Palaeontological, geomorphological and sedimentological data supported by isotopic dating on Oxygen
Isotopic Stage (OIS) 5e deposits from the Spanish Mediterranean coast, are interpreted with the aim of
reconstructing climatic instability in the Northern Hemisphere. Data point to marked climatic instability
during the Last Interglacial (OIS 5e), with a change in meteorological conditions and, consequently, in the
sedimentary environment. The oolitic facies generated during the first part of OIS 5e (ca. 135 kyr) shift into
reddish conglomeratic facies during the second part (ca. 117 kyr). Sea surface Temperature (SST) and salinity
are interpreted mainly on the basis of warm Senegalese fauna, which show chronological and spatial
differential distribution throughout the Western Mediterranean. Present hydrological and meteorological
conditions are used also as modern analogues to reconstruct climatic variability throughout the Last
Interglacial, and this variability is interpreted within the wider framework of the North Atlantic record. All
the available data indicate an increase in storminess induced by an increase in the influence of northwesterlies,
a slight drop of SST in the northern Western Mediterranean, and an important change in
meteorological conditions at the end of OIS 5e (117 kyr). These changes correlate well with the decrease in
summer insolation and with the climatic instability recorded in North Atlantic high latitudes
An examination of the self-referent executive processing model of test anxiety: control, emotional regulation, self-handicapping, and examination performance
According to the self-referent executive processing (S-REF) model, test anxiety develops from interactions between three systems: executive self-regulation processes, self-beliefs, and maladaptive situational interactions. Studies have tended to examine one system at a time, often in conjunction with how test anxiety relates to achievement outcomes. The aim of this study was to enable a more thorough test of the S-REF model by examining one key construct from each of these systems simultaneously. These were control (a self-belief construct), emotional regulation through suppression and reappraisal (an executive process), and self-handicapping (a maladaptive situational interaction). Relations were examined from control, emotional regulation, and self-handicapping to cognitive test anxiety (worry), and subsequent examination performance on a high-stakes test. Data were collected from 273 participants in their final year of secondary education. A structural equation model showed that higher control was indirectly related to better examination performance through lower worry, higher reappraisal was indirectly related to worse examination performance through higher worry, and higher self-handicapping was related to worse examination performance through lower control and higher worry. These findings suggest that increasing control and reducing self-handicapping would be key foci for test anxiety interventions to incorporate. © 2018 The Author(s
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The corticotropin releasing factor stimulation test in patients with major depression: Relationship to dexamethasone suppression test results
Depressed patients have been reported to exhibit both a blunted ACTH response to corticotropin‐releasing factor (CRF) and abnormal suppression of plasma cortisol following the administration of dexamethasone. The purpose of the study was to determine the relationship between these two abnormalities. Twenty‐three depressed patients and eighteen control subjects received both a standard CRF stimulation test and the dexamethasone suppression test (DST). Nonsuppressors on the DST exhibited a blunted ACTH response to CRF; DST suppressors exhibited a normal ACTH response to CRF. This suggests that the two abnormalities of the hypothalamic‐pituitary‐adrenal (HPA) axis are related and may be due to similar pathopbysiological mechanisms. Depression 1:133–136 (1993). © 1993 Wiley‐Liss, Inc
GABAA receptor dephosphorylation followed by internalization is coupled to neuronal death in in vitro ischemia
Cerebral ischemia is characterized by an early disruption of GABAergic neurotransmission contributing to an imbalance
of the excitatory/inhibitory equilibriumand neuronal death, but the molecular mechanisms involved are
not fully understood. Here we report a downregulation of GABAA receptor (GABAAR) expression, affecting both
mRNA and protein levels of GABAAR subunits, in hippocampal neurons subjected to oxygen-glucose deprivation
(OGD), an in vitro model of ischemia. Similar alterations in the abundance of GABAAR subunits were observed
in in vivo brain ischemia. OGD reduced the interaction of surface GABAAR with the scaffold protein gephyrin,
followed by clathrin-dependent receptor internalization. Internalization of GABAARwas dependent on glutamate
receptor activation and mediated by dephosphorylation of the β3 subunit at serine 408/409. Expression of
phospho-mimetic mutant GABAAR β3 subunits prevented receptor internalization and protected hippocampal
neurons from ischemic cell death. The results show a key role for β3 GABAAR subunit dephosphorylation in
the downregulation of GABAergic synaptic transmission in brain ischemia, contributing to neuronal death.
GABAAR phosphorylation might be a therapeutic target to preserve synaptic inhibition in brain ischemia.Thiswork was funded by Fundação para a Ciência e a Tecnologia (FCT)
and Fundo Europeu para o Desenvolvimento Regional (FEDER) (Pest-C/
SAU/LA0001/2011 and PTDC/NEU-NMC/0198/2012) and the Swedish Research
Council (grant no. 8466)
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