We present an analysis of the constraining power of future measurements of the Integrated Sachs-Wolfe (ISW) effect on models of the equation of state of dark energy as a function of redshift, w(z). To achieve this, we employ a new parameterization of w, which utilizes the mean value of w(z) ( w ) as an explicit parameter. This helps to separate the information contained in the estimation of the distance to the last scattering surface (from the CMB) from the information contained in the ISW effect. We then use Fisher analysis to forecast the expected uncertainties in the measured parameters from future ISW observations for two models of dark energy with very different time evolution properties. For example, we demonstrate that the cross-correlation of Planck CMB data and LSST galaxy catalogs will provide competitive constraints on w(z), compared to a SNAP-like SNe project, for models of dark energy with a rapidly changing equation of state (e.g. "Kink" models). Our work confirms that, while SNe measurements are more suitable for constraining variations in w(z) at low redshift, the ISW effect can provide important independent constraints on w(z) at high z.PACS numbers:
We show that a positive accelerating universe can be obtained simply by the dynamics of a non-Abelian gauge group. The condensates of the chiral fields obtain a negative power potential below the condensation scale Lambda(c) and allow for a quintessence interpretation of these fields. The only free parameters are N(c), N(f), and the number of dynamically gauge singlet bilinear fields straight phi generated below Lambda(c). We show that it is possible to have unification of all coupling constants, while having an acceptable phenomenology of straight phi as quintessance, without any fine-tuning of the initial conditions. The coincidence problem is not solved but it is put at the same level as that of the particle content of the standard model.
Objectives
The current study aimed at evaluating the reliability, convergent and divergent validity, and factor structure of the Spanish Launay–Slade Hallucinations Scale‐Extended version (LSHS‐E) in people with mental disorders and healthy controls.
Methods
Four hundred and twenty‐two individuals completed the Spanish LSHS‐E and the Spanish Community Assessment of Psychic Experiences. The convergent and divergent validity of the LSHS‐E was assessed with the three dimensions of the Community Assessment of Psychic Experiences (positive, negative, and depressive dimensions) in healthy controls and people with a mental disorder. Factor structure of the LSHS‐E was assessed using confirmatory factor analysis and measurement invariance.
Results
The LSHS‐E had a good reliability in healthy controls and people with a mental disorder (Cronbach's = 0.83 and 0.91, respectively). The LSHS‐E was more strongly associated with positive psychotic‐like experiences than with depressive and negative symptoms. Four factors were found: (a) “intrusive thoughts”; (b) “vivid daydreams”; (c) “multisensory hallucination‐like experiences”; and (d) “auditory–visual hallucination‐like experiences” that were invariant between the group of healthy controls and people with a mental disorder.
Conclusion
The Spanish version of the LSHS‐E possesses adequate psychometric properties, and the confirmatory factor analysis findings provide further support for the multidimensionality of proneness to hallucination in clinical and nonclinical samples.
We study the cosmological evolution of scalar fields that arise from a phase transition at some energy scale ⌳ c . We focus on negative power potentials given by Vϭc⌳ c 4ϩn Ϫn and restrict the cosmologically viable values of ⌳ c and n. We make a complete analysis of V and impose SN1a conditions on the different cosmological parameters. The cosmological observations ruled out models where the scalar field has reached its attractor solution. For models where this is not the case, the analytic approximated solutions are not good enough to determine whether a specific model is phenomenologically viable or not and the full differential equations must be solved numerically. The results are not fine-tuned since a change of 45% in the initial conditions does not spoil the final results. We also determine the values of N c and N f that give a condensation scale ⌳ c consistent with gauge coupling unification, leaving only four models that satisfy unification and SN1a constraints.
Although there is recent evidence that cells from the peripheral immune system can gain access to the central nervous system in certain conditions such as multiple sclerosis, their role has not been assessed in psychosis. Here, we aimed to explore whether blood cell count was associated with brain volume and/or clinical symptomatology. A total of 218 participants (137 first-episode psychosis patients [FEP] and 81 healthy controls [HC]) were included in the study. For each participant, a T1 structural image was acquired, from which brain tissue volumes were calculated. We found that, in FEP, neutrophil count was associated with reduced gray matter (GM) volume (β = -0.117, P < .001) and increased cerebrospinal fluid volume (β = 0.191, P = .007). No associations were observed in HC. GM reduction was generalized but more prominent in certain regions, notably the thalamus, the anterior insula, and the left Heschl's gyrus, among many others. Neutrophil count was also associated with the total PANSS score (β = 0.173, P = .038), including those items assessing hallucinations (β = 0.182, P = .028) and avolition (β = 0.197, P = .018). Several confounders, such as antipsychotic medication, body mass index, and smoking, were controlled for. Overall, the present study may represent the first indirect evidence of brain tissue loss associated with neutrophils in psychosis, and lends support to the hypothesis of a dysregulated immune system. Higher neutrophil count was also associated with more severe clinical symptomatology, which renders it a promising indicator of schizophrenia severity and could even give rise to new therapies.
Background: Previous research suggests that visual hallucinations in schizophrenia consist of mental images mistaken for percepts due to failure of the reality-monitoring processes. However, the neural substrates that underpin such dysfunction are currently unknown. We conducted a brain imaging study to investigate the role of visual mental imagery in visual hallucinations. Method: Twenty-three patients with schizophrenia and 26 healthy participants were administered a reality-monitoring task whilst undergoing an fMRI protocol. At the encoding phase, a mixture of pictures of common items and labels designating common items were presented. On the memory test,
The main objective of this study is to identify fibromyalgia syndrome (FMS) clusters using the Revised Fibromyalgia Impact Questionnaire (FIQR), and to examine whether the clusters differ in sociodemographic characteristics, clinical measures, direct and indirect costs, levels of inflammatory markers, and brain morphometry. A hierarchical cluster analysis was performed to classify a large, pooled Spanish sample of patients with FMS (N = 947) using the FIQR as clustering variable. A latent profile analysis was subsequently conducted to confirm the optimal number of FMS clusters. To examine external validity, a battery of clinical measures, economic costs, inflammatory markers, and gray matter volumes of relevant cortical and subcortical areas were analyzed. We also compared the discriminant validity of the clusters with the original FIQR severity categories. To promote the implementation in real-world clinical practice, we built a free online cluster calculator. Our findings indicated that a four-cluster solution more clearly captured the heterogeneity of FIQR data and provided the best fit. This cluster solution allowed for detection of differences for most clinical outcomes and economic costs. Regarding the inflammatory and brain-based biomarkers, differences were found in C-reactive protein, and tendencies were found in the right medial prefrontal cortex, the right parahippocampal gyrus, and the right middle cingulate cortex; brain regions associated with executive functions and pain processing. The original FIQR categories presented similar results, although their precision in discriminating among the nonextreme categories (ie, moderate and severe) was not sound. These findings are discussed in relation to previous research on FMS clustering.
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