Cognitive predictors of relapse have been extensively explored only in few long term longitudinal studies of first-episode schizophrenia.
This study prospectively followed 93 patients with ...first-episode schizophrenia, schizophreniform disorder, and schizoaffective disorder for 3 years after their first-episode illness. Cognitive domains including verbal intelligence, verbal and visual memory, verbal fluency, and Wisconsin Card Sorting Test performance were investigated as potential predictors of relapse.
We found that by the first year 21% patients had relapsed, by the second year 33% had relapsed, and by the third year 40% had relapsed. There was a significant difference in the relapse rate between patients with good adherence and patients with poor adherence to medication regimes. A multiple logistic regression analysis revealed that after controlling for medication adherence, perseverative error in the Wisconsin Card Sorting Test was the only cognitive function that significantly predict relapse with an odds ratio of 2.4.
Cognitive flexibility in set shifting is related to tendency towards relapse in first-episode schizophrenic patients. Other cognitive factors appear not to be related to relapse. Possible mechanisms included the link between prefrontal dysfunction and sub-cortical dopamine system stability, as well as the effects of executive dysfunction on insight impairment and adherence behavior.
Neurological soft signs are biological traits that underlie schizophrenia and are found to occur at higher levels in at-risk individuals. The expression of neurological soft signs may be modifiable ...during the onset of the first psychotic episode and the subsequent evolution of the illness and its treatment. This study investigates neurological soft signs in 138 patients with first-episode schizophrenia and tracks the expression of motor soft signs in the following 3 years. For the 93 patients who have completed the 3-year follow-up, we find that neurological soft signs are stable in the 3 years that follow the first psychotic episode, and that neurological soft signs are already elevated at the presentation of first-episode psychosis in medication-naïve subjects. The level of neurological soft signs at clinical stabilization is lower for patients with a shorter duration of untreated psychosis. Although the quantity of neurological soft signs does not significantly change in the 3 years that follow the first episode, the relationship between neurological soft signs and negative symptoms does not become apparent until 1 year after the initial episode. A higher level of neurological soft signs is related to a lower educational level and an older age at onset, but the level of neurological soft signs does not predict the outcome in terms of relapse or occupational functioning.
Previous family experience of psychotic illness may play an important role in whether and when a patient seeks help in first-episode psychosis. This study investigated the relationship between family ...experience of psychosis and the duration of untreated psychosis in a prospective sample of first-episode psychosis patients in Hong Kong. We also studied the effects of pre-morbid adjustment, educational level, living alone, and mode of onset as potential determinants of the duration of untreated psychosis (DUP).
A total of 131 first-episode psychosis patients in Hong Kong were recruited in a study of the DUP and related factors. The Interview for the Retrospective Assessment of the Onset of Schizophrenia (IRAOS) was used to measure the DUP and to provide a structured assessment of family history, educational level, household arrangement, and mode of onset.
Previous family experience of psychiatric illness (the presence of another family member who has been receiving psychiatric treatment) and an acute mode of onset were significant predictors of a shorter DUP. Educational level had a modest effect on its own, but was not significant in the binary logistic regression model. Living alone had a moderate effect size, but was non-significant, possibly because of the small proportion of single-person households in the sample. The symptom profile, pre-morbid adjustment, and other demographic factors were not significantly related to the DUP.
In addition to the mode of onset, previous family experience plays an important role in the presentation of early psychosis. Educational efforts that target the family should be an important part of any strategy for the early detection of psychosis.
Abstract Semantic categorization abnormalities have been observed in schizophrenia, but studies have rarely focused on the longitudinal trajectory. In this study, we consider semantic performance and ...the relationship with symptomatic changes during recovery from a first-episode of schizophrenia over a period of 3 years. Thirty-seven first-episode patients with schizophrenia were compared to thirty-seven matched controls in a categorization task. Patients were assessed at first episode, after clinical stabilization, and annually for the subsequent 3 years. In the task, participants indicated whether a word belonged to a given category. Each category contained words of varying degrees of semantic relatedness: typical, atypical, borderline, related-but-outside, and unrelated. Reaction times and proportion of ‘yes’ responses were analyzed. At first assessment, semantic categorization abnormalities were observed in first-episode patients. Patients assigned more semantically-dissimilar words to the categories than controls. As patients stabilized from acute states, their semantic categorization performance improved and then remained stable throughout the entire follow up period of 3 years. Interestingly, semantic performance deficits, particularly a diminished typicality effect, correlated with negative symptoms in the initial episode, but not at stabilization when symptoms subsided. No significant associations between positive and negative symptoms, or pre-defined categorization measures were identified. The data demonstrated semantic memory abnormalities in first-episode schizophrenia. However, an improvement of semantic categorization performance was observed in stabilized schizophrenia patients. Overall, the data are suggestive of a state effect in semantic abnormalities rather than a trait effect. The correlation between degree of impairment and symptoms may explain previous inconsistent findings.
Hashimoto's encephalopathy may present with a variety of neurological symptoms and signs, including myoclonus, epileptic seizures, disturbance of consciousness, psychosis, ataxia, and presenile ...dementia. This report is of a 57-year-old woman with a history of thyroid disease who was investigated for generalised seizures, rapid decline in cognitive function, increasing dependency, and gradual change in personality. High thyroid autoantibody titres confirmed the diagnosis of Hashimoto's encephalopathy and her symptoms improved with treatment with prednisolone. The differential diagnosis of presenile dementia, aetiology and pathogenesis of Hashimoto's encephalomyelitis, and treatment options are discussed. Hashimoto's encephalomyelitis should be considered in the differential diagnosis of presenile dementia, particularly in patients with a history of thyroid disease.
We use transient electrical measurements to investigate the details of self-heating and charge trapping in graphene transistors encapsulated in hexagonal boron nitride (h-BN) and operated under ...strongly nonequilibrium conditions. Relative to more standard devices fabricated on SiO2 substrates, encapsulation is shown to lead to an enhanced immunity to charge trapping, the influence of which is only apparent under the combined influence of strong gate and drain electric fields. Although the precise source of the trapping remains to be determined, one possibility is that the strong gate field may lower the barriers associated with native defects in the h-BN, allowing them to mediate the capture of energetic carriers from the graphene channel. Self-heating in these devices is identified through the observation of time-dependent variations of the current in graphene and is found to be described by a time constant consistent with expectations for nonequilibrium phonon conduction into the dielectric layers of the device. Overall, our results suggest that h-BN-encapsulated graphene devices provide an excellent system for implementations in which operation under strongly nonequilibrium conditions is desired.
EXPLAINING EXTREME EVENTS OF 2016 Herring, Stephanie C.; Christidi, Nikolaos; Hoell, Andrew ...
Bulletin of the American Meteorological Society,
01/2018, Letnik:
99, Številka:
1
Journal Article
Recenzirano
This sixth edition of explaining extreme events of the previous year (2016) from a climate perspective is the first of these reports to find that some extreme events were not possible in a ...preindustrial climate. The events were the 2016 record global heat, the heat across Asia, as well as a marine heat wave off the coast of Alaska. While these results are novel, they were not unexpected. Climate attribution scientists have been predicting that eventually the influence of human-caused climate change would become sufficiently strong as to push events beyond the bounds of natural variability alone. It was also predicted that we would first observe this phenomenon for heat events where the climate change influence is most pronounced. Additional retrospective analysis will reveal if, in fact, these are the first events of their kind or were simply some of the first to be discovered.
Last year, the editors emphasized the need for additional papers in the area of “impacts attribution” that investigate whether climate change’s influence on the extreme event can subsequently be directly tied to a change in risk of the socio-economic or environmental impacts. Several papers in this year’s report address this challenge, including Great Barrier Reef bleaching, living marine resources in the Pacific, and ecosystem productivity on the Iberian Peninsula. This is an increase over the number of impact attribution papers than in the past, and are hopefully a sign that research in this area will continue to expand in the future.
Other extreme weather event types in this year’s edition include ocean heat waves, forest fires, snow storms, and frost, as well as heavy precipitation, drought, and extreme heat and cold events over land. There were a number of marine heat waves examined in this year’s report, and all but one found a role for climate change in increasing the severity of the events. While human-caused climate change caused China’s cold winter to be less likely, it did not influence U.S. storm Jonas which hit the mid-Atlantic in winter 2016.
As in past years, the papers submitted to this report are selected prior to knowing the final results of whether human-caused climate change influenced the event. The editors have and will continue to support the publication of papers that find no role for human-caused climate change because of their scientific value in both assessing attribution methodologies and in enhancing our understanding of how climate change is, and is not, impacting extremes. In this report, twenty-one of the twenty-seven papers in this edition identified climate change as a significant driver of an event, while six did not. Of the 131 papers now examined in this report over the last six years, approximately 65% have identified a role for climate change, while about 35% have not found an appreciable effect.
Looking ahead, we hope to continue to see improvements in how we assess the influence of human-induced climate change on extremes and the continued inclusion of stakeholder needs to inform the growth of the field and how the results can be applied in decision making. While it represents a considerable challenge to provide robust results that are clearly communicated for stakeholders to use as part of their decision-making processes, these annual reports are increasingly showing their potential to help meet such growing needs.
Size-selected anionic silicon clusters, Sin- (n=14-20), have been investigated by photoelectron spectroscopy and density functional theory (DFT) calculations. Low-energy structures of the clusters ...are globally searched for by using a genetic algorithm based on DFT calculations. The electronic density of states and VDEs have been simulated by using ten DFT functionals and compared to the experimental results. We systematically evaluated the DFT functionals for the calculation of the energetics of silicon clusters. CCSD(T) single-point energies based on MP2 optimized geometries for selected isomers of Sin- are also used as benchmark for the energy sequence. The HSE06 functional with aug-cc-pVDZ basis set is found to show the best performance. Our global minimum search corroborates that most of the lowest-energy structures of Sin- (n=14-20) clusters can be derived from assembling tricapped trigonal prisms (TTP) in various ways. For most sizes previous structures are confirmed, whereas for Si20- a new structure has been found.
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