Gravitational wave recoils in non-axisymmetric Robinson-Trautman spacetimes

We examine the gravitational wave recoil waves and the associated net kick velocities in non-axisymmetric Robinson-Trautman spacetimes. We use characteristic initial data for the dynamics corresponding to non-head-on collisions of black holes. We make a parameter study of the kick distributions, corresponding to an extended range of the incidence angle $\rho_0$ in the initial data. For the range of $\rho_0$ examined ($3^{\circ} \leq \rho_0 \leq 110^{\circ}$) the kick distributions as a function of the symmetric mass parameter $\eta$ satisfy a law obtained from an empirical modification of the Fitchett law, with a parameter $C$ that accounts for the non-zero net gravitational momentum wave fluxes for the equal mass case. The law fits accurately the kick distributions for the range of $\rho_0$ examined, with a rms normalized error of the order of $5 \%$. For the equal mass case the nonzero net gravitational wave momentum flux increases as $\rho_0$ increases, up to $\rho_0 \simeq 55^{\circ}$ beyond which it decreases. The maximum net kick velocity is about $190 {\rm km/s}$ for for the boost parameter considered. For $\rho_0 \geq 50^{\circ}$ the distribution is a monotonous function of $\eta$. The angular patterns of the gravitational waves emitted are examined. Our analysis includes the two polarization modes present in wave zone curvature.Comment: 10 pages, 5 figures. arXiv admin note: substantial text overlap with arXiv:1403.4581, arXiv:1202.1271, arXiv:1111.122

Towards BitCO2, an individual consumption-based carbon emission reduction mechanism

Human activities, such as burning fossil fuels for electricity generation, heating, and transport, are the primary drivers of a large amount of greenhouse gases emission. The individual consumers, able to influence the supply chains behind the commodities their chose to fulfil their needs is the driver behind production and, consequently, its impacts. Thus, the active and willing participation of citizens in combatting climate change may be pivotal to address this issue. The present work is aimed at presenting and modelling a novel market-based carbon emission reduction mechanism, called BitCO2, designed to incentivize individual consumption choices toward lower carbon footprints. This mechanism is tested for the Italian private transportation sector thanks to an ad hoc developed System Dynamics model. The Battery Electric Vehicle (BEV) adoption, if compared with the Internal Combustion Engine Vehicle (ICEV) one, cause less CO2 emissions per km travelled. After a certain number of travelled km, a BitCO2 token is assigned to BEV owners for each ton of avoided CO2. This token can be exchanged in a dedicated market and used to get a discount on insurance services. Assuming a Social Cost of Carbon of 9.22 [2.13-22.3] euro/tonCO2eq, model results show that the BitCO2 mechanism would allow for a cumulated CO2 emission reduction of 973 [68.9-5'230] ktonCO2eq over 20 years of operation with a peak of 39.3 [5.34-189] thousand additional BEV registration per year

The low dimensional dynamical system approach in General Relativity: an example

In this paper we explore one of the most important features of the Galerkin method, which is to achieve high accuracy with a relatively modest computational effort, in the dynamics of Robinson-Trautman spacetimes.Comment: 7 pages, 5 figure

Cumulative sociodemographic disadvantage partially mediates associations between childhood trauma and schizotypy

Objectives: Risk for psychosis in the general population is characterized by a set of multidimensional traits that are referred to as schizotypy. Higher levels of schizotypy are associated with socioeconomic disadvantage and childhood trauma, just as these risk factors are associated with schizophrenia and bipolar disorder. Here, we set out to investigate whether cumulative sociodemographic disadvantage mediates associations between childhood trauma and schizotypy in adulthood. Methods: A sociodemographic cumulative risk (SDCR) score was derived from six risk indices spanning employment, education, income, socioeconomic status, marital, and living circumstances for 197 participants that included both healthy (n = 57) and clinical samples with schizophrenia or schizoaffective disorder (n = 65) or bipolar disorder (n = 75). A series of multiple linear regressions was used to examine the direct and indirect associations among childhood trauma (measured with the Childhood Trauma Questionnaire), the SDCR index, and levels of schizotypy (measured with the Schizotypal Personality Questionnaire). Results: Schizotypy was independently associated with trauma and the SDCR index. In addition, the SDCR index partially mediated associations between trauma and schizotypy. Conclusions: These findings in a mixed sample of healthy and clinical participants represent the full spectrum of schizotypy across health and illness and suggest that effects of childhood trauma on schizotypal personality organization may operate via cumulative socioeconomic disadvantage in adulthood. Practitioner points: The strong associations between trauma and schizotypy suggest that systematic health screening of children exposed to early life trauma may assist to identify those at risk of developing psychosis. Clinicians should pay attention to various indicators of sociodemographic disadvantage in patients prone to psychosis, in addition to any exposure to trauma during childhood

Schizotypy, childhood trauma and brain morphometry

Background: Childhood trauma confers risk for psychosis and is associated with increased ‘schizotypy’ (a multi-dimensional construct reflecting risk for psychosis in the general population). Structural brain alterations are associated with both childhood trauma and schizotypy, but the potential role of trauma exposure in moderating associations between schizotypy and brain morphology has yet to be determined. Methods: Participants were 160 healthy individuals (mean age: 40.08 years, SD = 13.64, range 18–64; 52.5% female). Childhood trauma exposure was assessed using the Childhood Adversity Questionnaire, and schizotypy was assessed using the Schizotypal Personality Questionnaire. Univariate voxel-based morphometry and multivariate analyses of grey matter volume covariation (GMC; derived from independent component analysis) were performed to determine the main effects of schizotypy, trauma exposure and their interaction on these indices of grey matter volume. Moderation analyses were performed following significant interaction. Results: Levels of schizotypy, in particular the Cognitive-Perceptual and Interpersonal dimensions, were negatively associated with GMC in the striatum, the hippocampus/parahippocampal gyrus, thalamus and insulae. Trauma exposure was negatively associated with GMC of the middle frontal gyrus and parietal lobule, while negatively associated with GMC in the cerebellum. Levels of schizotypy (total scores, and the cognitive-perceptual dimension) were negatively associated with striatal GMC in individuals not exposed to trauma, but not in those exposed to trauma. Conclusions: Schizotypy and childhood trauma were independently associated with changes of grey matter in brain regions critical for cognition and social cognition. In individuals not exposed to trauma, increased schizotypy was associated with decreased striatal and limbic grey matter

Structural and Functional Neural Correlates of Schizotypy: A Systematic Review

Schizotypy refers to a multidimensional construct that spans a range of cognitive, behavioral, and personality features, representing liability to psychosis on a continuum between health and illness. Schizotypy has been associated with functional and structural brain alterations as potential intermediate phenotypes on the developmental path to psychosis. We scanned the literature between February 2019 and August 1, 2020 using PubMed, Medline, APA PsycINFO, and ProQuest. We identified eligible articles conducted on participants assessed with psychometric schizotypy across the health-illness spectrum and reporting a direct statistic between schizotypy and a structural, task-related, or functional magnetic resonance imaging brain measure. Articles not peer-reviewed and not written in English were excluded. We systematically reviewed 84 studies that determined the changes in gray matter, brain activation, and connectivity associated with schizotypy in both healthy and clinical cohorts. Morphological and functional changes in the default and the frontoparietal networks, specifically frontal and temporal cortices, were most frequently associated with schizotypy. Yet, we were unable to identify consistent patterns of morphological or functional brain aberration associated with schizotypy, due to methodological differences between studies in the conceptualization and measurement of schizotypy. Efforts toward greater methodological concordance in future neuroimaging research of schizotypy are needed to improve the identification of brain-based endophenotypes for schizophrenia