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Positive symptoms are a useful predictor of aggression in schizophrenia. Although a similar pattern of abnormal brain structures related to both positive symptoms and aggression has been reported, this observation has not yet been confirmed in a single sample.
To study the association between positive symptoms and aggression in schizophrenia on a neurobiological level, a prospective meta-analytic approach was employed to analyze harmonized structural neuroimaging data from 10 research centers worldwide. We analyzed brain MRI scans from 902 individuals with a primary diagnosis of schizophrenia and 952 healthy controls.
The result identified a widespread cortical thickness reduction in schizophrenia compared to their controls. Two separate meta-regression analyses revealed that a common pattern of reduced cortical gray matter thickness within the left lateral temporal lobe and right midcingulate cortex was significantly associated with both positive symptoms and aggression.
These findings suggested that positive symptoms such as formal thought disorder and auditory misperception, combined with cognitive impairments reflecting difficulties in deploying an adaptive control toward perceived threats, could escalate the likelihood of aggression in schizophrenia.
The application of linguistics to legal issues—what some have labelled “forensic linguistics”—has become increasingly common, varied and consequential (see Brackenridge 1981 for a brief overview). Recently, we three served as language experts in Toronto’s first bilingual jury trial (Regina vs. Lapointe and Sicotte, 1981). Since each of us was assigned a different linguistic problem and since our roles were partially adversary ones (two of us worked for the defence and the other for the prosecution), we were able to draw upon a variety of linguistic concepts and analyses as well as to assess their effectiveness when applied to legal issues. The present paper reports not only on the nature of our involvement but, more importantly, on our joint perception of disturbing language-related problems in the legal process and of equally disturbing inadequacies in the responses that linguistics can currently offer to many of these problems.
Our Commission decided to proceed as before, with a rather comprehensive report, while focusing on the subjects where most progress has been achieved during the past three years. The colleagues who kindly contributed to it are W. Dziembowski (helio- and aster-oseismology), J. Guzik (intermediate-mass stars), G. Meynet (massive stars), G. Michaud (atomic diffusion), D. VandenBerg (low mass stars), G. Vauclair (white dwarfs), J.-P. Zahn (convection, rotational mixing).
We present models for Type I supernova light curves based on the explosion of partially solid white dwarfs in close binary systems. Studies of such explosions show that they leave bound remnants of different size. Our results reproduce quite well the maximun luminosities, the expansion velocities and the shape of the light curve. As the two basic papameters that govern the light curve, the ejected mass and the mass of 56Ni produced, are variable our models reproduce the slow and fast subclasses of “classical” Type I supernovae.
Massive star (M ≥ 10 M ) core collapse is the standard mechanism for neutron star formation (see Brown 1988 for a recent review). It has long been realized (see, for instance, van den Heuvel 1988, and references therein) that the neutron stars found in different types of binary systems cannot come from such a standard mechanism. Those systems include wide binary radio pulsars, millisecond pulsars (not in wide binaries), galactic bulge X–ray sources (including QPO’s), type I X–ray burst sources and X–ray transients, andγ–ray sources. Formation of those neutron stars is now widely attributed to the gravitational collapse of a white dwarf, growing above Chandrasekhar’s limit by mass accretion from the current neutron star’s companion in the binary system (Canal and Schatzman 1976; Canal and Isern 1979; Canal, Isern, and Labay 1980; Miyaji et al. 1980). Mass growth up to dynamical instability means that both explosive ejection of the accreted layers and explosive disruption of the whole star must be avoided. The former is associated with the nova phenomenon. The latter, with the occurrence of type I supernovae.
In this paper we review the behavior of growing stellar degenerate cores. It is shown that ONeMg white dwarfs and cold CO white dwarfs can collapse to form a neutron star. This collapse is completely silent since the total amount of radioactive elements that are expelled is very small and a burst of γ-rays is never produced. In the case of an explosion (always carbonoxygen cores), the outcome fits quite well the observed properties of Type Ia supernovae. Nevertheless, the light curves and the velocities measured at maximum are very homogeneous and the diversity introduced by igniting at different densities is not enough to account for the most extreme cases observed. It is also shown that a promising way out of this problem could be the He-induced detonation of white dwarfs with different masses. Finally, we outline that the location of the border line which separetes explosion from collapse strongly depends on the input physics adopted.
A hydrodynamic formulation for accretion flow channeled by a dipolar magnetic field is constructed using a curvi-linear coordinate system natural to the field structure. We solve the hydrodynamic equations and determine the velocity, density and temperature profiles of the post-shock accretion flow. The results are applied to accretion flows in intermediate polars. We have found that for systems with massive white dwarfs (~ 1 M⊙) the temperature profiles in the flow can differ significantly to those obtained from models in which the accretion column is assumed to be cylindrical.
There is observational evidence of the presence of young neutron stars in old binary systems. A likely explanation is that those neutron stars were produced in the collapse of old CO white dwarfs. We show how mass accretion on initially solid white dwarfs can leave central solid cores when dynamical instability sets in and we study the different effects of the existence of such cores on the outcome of the competition between thermonuclear explosion and gravitational collapse.
Stress and negative emotions pose a major threat to public health, by increasing the risk of obesity. Since the management process for emotions (emotion regulation; ER) is developed in childhood, we present a novel conceptual framework model for the role of ER in the prevention and treatment of childhood obesity. A narrative review of the literature by electronic database search (MEDLINE, Web of Knowledge and Scopus) was conducted of observational and interventional/experimental literature on ER and obesity and the underlying concepts. We also present an overview of ER intervention techniques. Our model indicates that childhood ER is a link between stress and obesity. Stress along with ineffective ER leads to abnormal cortisol patterns, emotional eating, sedentary lifestyle, reduction of physical activity, and sleep problems. Simultaneously, a healthy lifestyle could show benefits on ER and in developing adaptive ER strategies. In the development of obesity and ER, parents also play a role. By contrast, effective ER skills decrease obesity-related unhealthy behaviour and enhance protective factors, which boost health. The literature contains some observational studies of children but very few intervention studies, most of which are pilot or on-going studies. In conclusion, encouraging effective ER could be a useful new approach for combating and treating childhood obesity. Future ER intervention studies are needed to confirm the validity of this model in children.
Delusional disorder has been the subject of very little investigation
using brain imaging.
To examine potential structural and/or functional brain abnormalities in
We used structural imaging (voxel-based morphometry, VBM) and functional
imaging (during performance of the n-back task and
whole-brain resting connectivity analysis) to examine 22 patients meeting
DSM-IV criteria for delusional disorder and 44 matched healthy
The patients showed grey matter reductions in the medial frontal/anterior
cingulate cortex and bilateral insula on unmodulated (but not on
modulated) VBM analysis, failure of de-activation in the medial
frontal/anterior cingulate cortex during performance of the
n-back task, and decreased resting-state connectivity
in the bilateral insula.
The findings provide evidence of brain abnormality in the medial
frontal/anterior cingulate cortex and insula in delusional disorder. A
role for the former region in the pathogenesis of delusions is consistent
with several other lines of evidence.
In humans, maximum brain development occurs between the third trimester of gestation and 2 years of life. Nutrition during these critical windows of rapid brain development might be essential for later cognitive functioning and behaviour. In the last few years, trends on protein recommendations during infancy and childhood have tended to be lower than that in the past. It remains to be demonstrated that lower protein intakes among healthy infants, a part of being able to reduce obesity risk, is safe in terms of mental performance achievement. Secondary analyses of the EU CHOP, a clinical trial in which infants from five European countries were randomised to be fed a higher or a lower protein content formula during the 1st year of life. Children were assessed at the age of 8 years with a neuropsychological battery of tests that included assessments of memory (visual and verbal), attention (visual, selective, focused and sustained), visual-perceptual integration, processing speed, visual-motor coordination, verbal fluency and comprehension, impulsivity/inhibition, flexibility/shifting, working memory, reasoning, visual-spatial skills and decision making. Internalising, externalising and total behaviour problems were assessed using the Child Behaviour Checklist 4–18. Adjusted analyses considering factors that could influence neurodevelopment, such as parental education level, maternal smoking, child’s gestational age at birth and head circumference, showed no differences between feeding groups in any of the assessed neuropsychological domains and behaviour. In summary, herewith we report on the safety of lower protein content in infant formulae (closer to the content of human milk) according to long-term mental performance.
The pathological basis of tardive dyskinesia is unknown. Although its clinical features implicate the basal ganglia, imaging studies have not found clear evidence that it is associated with volume changes in these or other brain structures.
To determine, using voxel-based structural imaging, whether there are regions of grey matter volume change in people with schizophrenia who also have tardive dyskinesia compared with those without tardive dyskinesia.
A total of 81 people with chronic schizophrenia, 32 with tardive dyskinesia and 49 without, were examined using magnetic resonance imaging (MRI) and whole-brain, optimised voxel-based morphometry. A comparison group of 61 healthy controls was also examined.
Compared with those without tardive dyskinesia, patients with tardive dyskinesia showed a pattern of volume reductions in predominantly subcortical regions, including the basal ganglia and the thalamus. Within the basal ganglia, volume reductions were seen in the caudate nucleus, to a lesser extent in the putamen, and only marginally in the globus pallidus. The patients with tardive dyskinesia, but not those without, showed significant volume reductions in the basal ganglia compared with the healthy controls but both groups had smaller volumes than controls in other affected areas.
The pathological process or processes that underlie the development of tardive dyskinesia are not just neurochemical in nature, but affect brain structure.
Mesoporous materials have typical average pore diameters in the range 20 – 500 Å, which are usually accompanied by high specific surface area (ABET) and large pore volume (Vp) with narrow pore size distributions. These features are very attractive for potential application as catalysts and adsorbents. Mesoporous materials are usually prepared by soft templating or nanocasting process. The latter approach is based on the replication of hard-templates, such as mesoporous silica (e.g. SBA-15), being a very flexible and suitable method to obtain stable and predictable pore mesostructures. However, the chemical compatibility between the template and the precursors must be ensured.
Cognitive impairment is an established feature of schizophrenia. However,
little is known about its relationship to the structural and functional
brain abnormalities that characterise the disorder.
To identify structural and/or functional brain abnormalities associated
with schizophrenic cognitive impairment.
We carried out structural magnetic resonance imaging (MRI) and
voxel-based morphometry in 26 participants who were cognitively impaired
and 23 who were cognitively preserved, all with schizophrenia, plus 39
matched controls. Nineteen of those who were cognitively impaired and 18
of those who were cognitively preserved plus 34 controls also underwent
functional MRI during performance of a working memory task.
No differences were found between the participants who were cognitively
intact and those who were cognitively impaired in lateral ventricular
volume or whole brain volume. Voxel-based morphometry also failed to
reveal clusters of significant difference in grey and white matter volume
between these two groups. However, during performance of the n-back task,
the participants who were cognitively impaired showed hypoactivation
compared with those who were cognitively intact in the dorsolateral
prefrontal cortex among other brain regions.
Cognitive impairment in schizophrenia is not a function of the structural
brain abnormality that accompanies the disorder but has correlates in
altered brain function.
Vibrational spectroscopy and various physical property measurements (density, molar volume and glass transformation temperature) were used to investigate the structural changes that occurred with changes in composition for glasses prepared by standard melting and quenching techniques in the PbO-Bi2O3-GeO2 system. Regions of constant glass transformation temperature (Tg) were noted for these glasses at high GeO2 compositions, as determined from DSC measurements. These results clearly indicated the presence of amorphous phase separation. A model was proposed that could qualitatively interpret both the infrared and Raman spectra, and the molar volume data. At low lead oxide and bismuth oxide concentrations, lead acted primarily as a network modifier while bismuth acted as a mixed network former and modifier. At high concentrations, both lead and bismuth acted as network formers in linking discrete GeO4-units and possibly forming a lead oxide/bismuth oxide portion of the network. The observed results were also interpreted on the basis of Ge-O bonds involving bridged and non-bridged oxygen atoms, and on the basis of a possible change in coordination for germanium from four to six with metal oxide additions.
We prepared porous silicon (PSi) structures by standard electrochemical processes using aqueous sodium fluoride (NaF) solutions. We report the dependence of the porous structure on the variation of pH and salt concentration of the etching solution, and the applied current density. The PSi structures were characterized by Scanning Electron Microscopy (SEM) and Secondary Ion Mass Spectroscopy (SIMS) to determine the pore size and distribution and the surface chemical composition. Results obtained from SEM show that the PSi grown has two different structures depending on the current density. Low current densities produce a uniform, high-density arrangement of pores while high current densities yield a sponge-like structural network. SIMS results indicate that the porous framework is covered with a silicon oxide layer.
Ticks are blood-feeding arthropods widely distributed in the world and vectors of several diseases. As haematophagy demands evasion strategies and repeatedly infested hosts develop protective immune responses, we investigated the mechanisms of the Rhipicephalus (Boophilus) microplus saliva anti-haemostatic activity and the possible relationship between the acquired natural anti-tick host resistance and anti-haemostatic action. For this purpose, we studied the effects of R. microplus saliva on different pathways of haemostasis and tested whether repeated infested bovine sera (RIBS) are able to abolish salivary anti-haemostatic activities. R. microplus saliva (i) displays inhibitory activity upon collagen-induced platelet aggregation; (ii) inhibits the induction of endothelial pro-coagulant state; and (iii) reduces thrombogenesis in vivo. RIBS were shown to be able to partially block the delay of coagulation and the anti-thrombotic effect of saliva, and to totally abolish the modulation of endothelium activation. Conversely, RIBS has no effect on the inhibition of platelet aggregation. These results show, for the first time, the neutralization ability of sera from acquired resistance hosts against tick anti-haemostatics. Moreover, this is the first report of a haematophagous parasite able to modulate endothelial cell pro-coagulant state, and addresses the presence of anti-platelet and anti-thrombotic activity in R. microplus saliva.
Walnut consumption produces beneficial cardiovascular effects. The aim of the present study is to compare the effects of meat enriched in walnut paste (WM) and low-fat meat (LM) consumptions on platelet aggregation, plasma thromboxane A2 (TXA2, measured as TXB2), prostacyclin I2 (PGI2, as 6-keto-PGF1α) and the thrombogenic ratio (TXB2/6-keto-PGF1α) in volunteers at high CVD risk. Twenty-two adults were placed on a random, non-blinded crossover study involving two test periods (five portions WM/week for 5 week; five portions LM/week for 5 week) separated by a 4- to 6-week washout period. The participants were asked to complete a diet record throughout the study. Platelet aggregation, plasma TXB2, 6-keto-PGF1α production and the TXB2/6-keto-PGF1α ratio were determined at baseline and at weeks 3 and 5 for the two dietary periods. The WM diet contains a lower SFA content, a higher concentration of PUFA and a more favourable n-6/n-3 ratio than the LM diet. Significant time × treatment interactions were observed for TXB2 (P = 0·048) and the TXB2/6-keto-PGF1α ratio (P = 0·028). The WM diet significantly increased the level of 6-keto-PGF1α (P = 0·037) and decreased the TXB2/6-keto-PGF1α ratio (P = 0·048). At week 5, significant differences (P < 0·05) between treatments were found for maximum aggregation rate, TXB2 values and the TXB2/6-keto-PGF1α ratio. The effects on TXB2 and the TXB2/6-keto-PGF1α ratio were time-course dependent (P = 0·019 and 0·011, respectively). The WM and LM diets reduced TXB2 levels most (P = 0·050) in obese individuals, while the TXB2/6-keto-PGF1α ratio decreased most (P = 0·066) in volunteers whose serum cholesterol levels were ≥ 2200 mg/l. The WM diet should be considered a functional meat because it improves the thrombogenic status mainly in individuals with high-cholesterol levels or high BMI.