Altered Cortical Ensembles in Mouse Models of Schizophrenia

In schizophrenia, brain-wide alterations have been identified at the molecular and cellular levels, yet how these phenomena affect cortical circuit activity remains unclear. We studied two mouse models of schizophrenia-relevant disease processes: chronic ketamine (KET) administration and Df(16)A+/-, modeling 22q11.2 microdeletions, a genetic variant highly penetrant for schizophrenia. Local field potential recordings in visual cortex confirmed gamma-band abnormalities similar to patient studies. Two-photon calcium imaging of local cortical populations revealed in both models a deficit in the reliability of neuronal coactivity patterns (ensembles), which was not a simple consequence of altered single neuron activity. This effect was present in ongoing and sensory-evoked activity and was not replicated by acute ketamine administration or pharmacogenetic parvalbumin-interneuron suppression. These results are consistent with the hypothesis that schizophrenia is an ‘‘attractor’’ disease and demonstrate that degraded neuronal ensembles are a common consequence of diverse genetic, cellular, and synaptic alterations seen in chronic schizophrenia

Relational Reality in Relativistic Quantum Mechanics

Up to now it has been impossible to find a realistic interpretation for the reduction process in relativistic quantum mechanics. The basic problem is the dependence of the states on the frame within which collapse takes place. A suitable use of the causal structure of the devices involved in the measurement process allows us to introduce a covariant notion for the collapse of quantum states.Comment: 4 pages, final version accepted for publication in Phys. Lett.

Investigating the prevalence of reactive online searching in the COVID-19 pandemic

Background: The ongoing coronavirus disease (COVID-19) pandemic has placed an unprecedented strain on global society, healthcare, governments and mass media. Public dissemination of government policies, medical interventions and misinformation has been remarkably rapid and largely unregulated during the COVID-19 pandemic, resulting in increased misinterpretations, miscommunication, and public panic. Being the first full-scale global pandemic of the digital age, COVID-19 has presented novel challenges pertinent to government advice, the spread of news and misinformation, and the trade-off between the accessibility of science and the premature public use of unproven medical interventions. Objective: This study aims to assess the use of internet search terms relating to COVID-19 information and misinformation during the global pandemic, identify which were most used in six affected countries, investigate any temporal trends and the likely propagators of key search terms, and determine any correlation between the per capita cases and deaths with the adoption of these search terms in each of the six countries. Methods: This study uses relative search volume data extracted from Google Trends for search terms linked to the COVID-19 pandemic alongside per capita case and mortality data extracted from the European Open Data Portal, to identify the temporal dynamics of the spread of news and misinformation during the global pandemic in six affected countries (Australia, Germany, Italy, Spain, United Kingdom, United States of America). A correlation analysis was carried out to ascertain any correlation between the temporal trends of search term use and the rise of per capita mortality and disease cases. Results: Of the selected search terms, most were searched immediately following promotion by governments, public figures or viral circulation of unfounded claims, but also relating to the publication of scientific resources, which were sometimes misinterpreted before further dissemination. Strong correlations were identified between the volume of these COVID-19-related search terms, and per capita mortality and cases. Conclusions: These findings illustrate the increased rate and volume of public consumption of novel information during a global healthcare crisis. The strong positive correlation between mortality and online searching, particularly in countries with lower COVID-19 testing rates, may demonstrate the imperative to safeguard official communications and dispel misinformation in these countries. Online news, government briefings and social media provide a powerful tool for the dissemination of important information to the public during pandemics, but their misuse, and the presentation of misrepresented medical information, should be monitored, minimised and addressed to safeguard public safety. Ultimately, governments, public health authorities and scientists have a moral imperative to safeguard the truth and maintain an accessible discourse with the public to inhibit fear

Modeling Wind-Driven Circulation and Chlorophyll Concentration in Lake Valencia

The goal of this research is to describe circulations patterns and chlorophyll concentration in Lake Valencia. The hydrodynamics of episodic events are simulated with a shallow-water model, coupled with an advection-diffusion equation. This model uses a MacCormack-TVD numerical scheme to solve the continuity and momentum equations simultaneously while the advection-diffusion equations determine the time dependent pollution dispersion, in particular the chlorophyll concentration. An analysis of chlorophyll concentration is completely developed and validated with satellite images of Lake Valencia. Although the use of shallow water models is a fairly standard in the study of lake circulation and chlorophyll concentration, its application to Lake Valencia is new. Therefore, the circulation and chlorophyll patterns developed in this numerical study represent an original contribution

MicroRNA-146a regulates ICOS–ICOSL signalling to limit accumulation of T follicular helper cells and germinal centres

Tight control of T follicular helper (Tfh) cells is required for optimal maturation of the germinal centre (GC) response. The molecular mechanisms controlling Tfh-cell differentiation remain incompletely understood. Here we show that microRNA-146a (miR-146a) is highly expressed in Tfh cells and peak miR-146a expression marks the decline of the Tfh response after immunization. Loss of miR-146a causes cell-intrinsic accumulation of Tfh and GC B cells. MiR-146a represses several Tfh-cell-expressed messenger RNAs, and of these, ICOS is the most strongly cell autonomously upregulated target in miR-146a-deficient T cells. In addition, miR-146a deficiency leads to increased ICOSL expression on GC B cells and antigen-presenting cells. Partial blockade of ICOS signalling, either by injections of low dose of ICOSL blocking antibody or by halving the gene dose of Icos in miR-146a-deficient T cells, prevents the Tfh and GC B-cell accumulation. Collectively, miR-146a emerges as a post-transcriptional brake to limit Tfh cells and GC responses.This work was funded by the National Health and Medical Research Council (NHMRC) program and project grants and Elizabeth Blackburn Fellowship to C.G.V., International Postgraduate Research Scholarship to A.P., NHMRC/MSRA Betty Cuthbert Fellowship to M.A.J., National Research Service Award F30HL110691 and UCLA/Caltech Medical Scientist Training Program to J.L.Z

Full genome sequence and sfRNA interferon antagonist activity of Zika virus from Recife, Brazil

Background: The outbreak of Zika virus (ZIKV) in the Americas has transformed a previously obscure mosquito-transmitted arbovirus of the Flaviviridae family into a major public health concern. Little is currently known about the evolution and biology of ZIKV and the factors that contribute to the associated pathogenesis. Determining genomic sequences of clinical viral isolates and characterization of elements within these are an important prerequisite to advance our understanding of viral replicative processes and virus-host interactions. Methodology/Principal findings: We obtained a ZIKV isolate from a patient who presented with classical ZIKV-associated symptoms, and used high throughput sequencing and other molecular biology approaches to determine its full genome sequence, including non-coding regions. Genome regions were characterized and compared to the sequences of other isolates where available. Furthermore, we identified a subgenomic flavivirus RNA (sfRNA) in ZIKV-infected cells that has antagonist activity against RIG-I induced type I interferon induction, with a lesser effect on MDA-5 mediated action. Conclusions/Significance: The full-length genome sequence including non-coding regions of a South American ZIKV isolate from a patient with classical symptoms will support efforts to develop genetic tools for this virus. Detection of sfRNA that counteracts interferon responses is likely to be important for further understanding of pathogenesis and virus-host interactions

Convergence Of Soil Nitrogen Isotopes Across Global Climate Gradients

Quantifying global patterns of terrestrial nitrogen (N) cycling is central to predicting future patterns of primary productivity, carbon sequestration, nutrient fluxes to aquatic systems, and climate forcing. With limited direct measures of soil N cycling at the global scale, syntheses of the N-15 : N-14 ratio of soil organic matter across climate gradients provide key insights into understanding global patterns of N cycling. In synthesizing data from over 6000 soil samples, we show strong global relationships among soil N isotopes, mean annual temperature (MAT), mean annual precipitation (MAP), and the concentrations of organic carbon and clay in soil. In both hot ecosystems and dry ecosystems, soil organic matter was more enriched in N-15 than in corresponding cold ecosystems or wet ecosystems. Below a MAT of 9.8 degrees C, soil delta N-15 was invariant with MAT. At the global scale, soil organic C concentrations also declined with increasing MAT and decreasing MAP. After standardizing for variation among mineral soils in soil C and clay concentrations, soil delta N-15 showed no consistent trends across global climate and latitudinal gradients. Our analyses could place new constraints on interpretations of patterns of ecosystem N cycling and global budgets of gaseous N loss.

EPOCHS VII: Discovery of high redshift (6.5<z<126.5 < z < 12) AGN candidates in JWST ERO and PEARLS data

We present an analysis of a sample of robust high redshift galaxies selected photometrically from the `blank' fields of the Prime Extragalactic Areas for Reionization Science (PEARLS) survey and Early Release Observations (ERO) data of the James Webb Space Telescope (JWST) with the aim of selecting candidate high redshift active galactic nuclei (AGN). Sources were identified from the parent sample using a threefold selection procedure, which includes spectral energy distribution (SED) fitting to identify sources that are best fitted by AGN SED templates, a further selection based on the relative performance of AGN and non-AGN models, and finally morphological fitting to identify compact sources of emission, resulting in a purity-oriented procedure. Using this procedure, we identify a sample of nine AGN candidates at $6.5 < z < 12$, from which we constrain their physical properties as well as measure a lower bound on the AGN fraction in this redshift range of $5 \pm 1$\%. As this is an extreme lower limit due to our focus on purity and our SEDs being calibrated for unobscured Type 1 AGN, this demonstrates that AGN are perhaps quite common at this early epoch. The rest-frame UV colors of our candidate objects suggest that these systems are potentially candidate obese black hole galaxies (OBG), or AGN with very little galaxy component. We also investigate emission from our sample sources from fields overlapping with Chandra and VLA surveys, allowing us to place X-ray and 3 GHz radio detection limits on our candidates. Of note is a $z = 11.9$ candidate source exhibiting an abrupt morphological shift in the reddest band as compared to the bluer bands, indicating a potential merger or an unusually strong outflow.Comment: Submitted to MNRAS, 12 pages, 11 figures, typos correcte