Cet article interroge l’expérience théâtrale vécue par le spectateur, telle qu’elle est présentée dans plusieurs discours contre le théâtre. Il examine ensuite le changement radical opéré sur cette ...question par Jean-Baptiste Dubos, théoricien de l’art et diplomate sous trois régimes politiques différents. La conclusion s’efforce de rattacher la question « comment fonctionnent les émotions théâtrales ? » à la construction stratégique, sociale et politique des émotions.
Dans Dramatic Experiments : Life according to Diderot, Eyal Peretz, philosophe et spécialiste de littérature comparée, interroge une polémique fondamentale concernant la réputation de Diderot. Selon ...lui, l’argument que le philosophe des Lumières nous a laissé une œuvre sans cohérence et confuse est douteux, et il entame, dans son ouvrage, une reconstitution et une réhabilitation de la réputation du fameux encyclopédiste. E. Peretz propose une étude sur la modernité et la rigueur philosophique...
Genome editing has therapeutic potential for treating genetic diseases and cancer. However, the currently most practicable approaches rely on the generation of DNA double-strand breaks (DSBs), which ...can give rise to a poorly characterized spectrum of chromosome structural abnormalities. Here, using model cells and single-cell whole-genome sequencing, as well as by editing at a clinically relevant locus in clinically relevant cells, we show that CRISPR-Cas9 editing generates structural defects of the nucleus, micronuclei and chromosome bridges, which initiate a mutational process called chromothripsis. Chromothripsis is extensive chromosome rearrangement restricted to one or a few chromosomes that can cause human congenital disease and cancer. These results demonstrate that chromothripsis is a previously unappreciated on-target consequence of CRISPR-Cas9-generated DSBs. As genome editing is implemented in the clinic, the potential for extensive chromosomal rearrangements should be considered and monitored.
Common envelope evolution on a moving mesh Prust, Logan J; Chang, Philip
Monthly notices of the Royal Astronomical Society,
07/2019, Letnik:
486, Številka:
4
Journal Article
Recenzirano
Odprti dostop
Abstract
We outline the methodology of simulating common envelope evolution (CEE) with the moving-mesh code manga. We extend manga to include multiple time-steps. This provides substantial speedups ...for problems with large dynamic range. We describe the implementation of realistic equations of state relevant in stellar structure and the generation of suitable initial conditions. We then carry out two example simulations of a 2 M⊙ red giant with a 0.36 M⊙ core and a 1 M⊙ companion undergoing CEE for 240 days. In one simulation the red giant is set into corotation with the orbital motion and in the other it is non-rotating. We find that the separation between the companion and red giant core shrinks from 52 R⊙ to 3.6 R⊙ and 3.2 R⊙, respectively, ending with an eccentricity of 0.1. We also find that 66 and 63 per cent of the envelope mass is ejected. This is higher than in many previous works. Several reasons for this are discussed. These include our inclusion of recombination energy. Our simulations show that putting giants in corotation increases the fraction of mass ejected from the system and results in a larger final orbital separation. We conclude that the entire envelope of the red giant might be ejected during the plunge phase of CEE in this region of parameter space.
The chromosome breakage-fusion-bridge (BFB) cycle is a mutational process that produces gene amplification and genome instability. Signatures of BFB cycles can be observed in cancer genomes alongside ...chromothripsis, another catastrophic mutational phenomenon. We explain this association by elucidating a mutational cascade that is triggered by a single cell division error-chromosome bridge formation-that rapidly increases genomic complexity. We show that actomyosin forces are required for initial bridge breakage. Chromothripsis accumulates, beginning with aberrant interphase replication of bridge DNA. A subsequent burst of DNA replication in the next mitosis generates extensive DNA damage. During this second cell division, broken bridge chromosomes frequently missegregate and form micronuclei, promoting additional chromothripsis. We propose that iterations of this mutational cascade generate the continuing evolution and subclonal heterogeneity characteristic of many human cancers.
COVID-19 has resulted in extraordinary disruptions to the higher education landscape. Here, we provide a brief report on 295 students' academic perceptions and emotional well-being in late May 2020. ...Students reported the high levels of uncertainty regarding their academic futures as well as significant levels of stress and difficulty coping with COVID-19 disruptions. These outcomes were related to the higher levels of neuroticism and an external locus of control. Female students reported worse emotional well-being compared to males, and the students of color reported the significantly higher levels of stress and uncertainty regarding their academic futures compared to White students. These results suggest that some students may be at particular risk for academic stress and poor emotional well-being due to the pandemic and highlight the urgent need for intervention and prevention strategies.
Mammalian transcriptomes display complex circadian rhythms with multiple phases of gene expression that cannot be accounted for by current models of the molecular clock. We have determined the ...underlying mechanisms by measuring nascent RNA transcription around the clock in mouse liver. Unbiased examination of enhancer RNAs (eRNAs) that cluster in specific circadian phases identified functional enhancers driven by distinct transcription factors (TFs). We further identify on a global scale the components of the TF cistromes that function to orchestrate circadian gene expression. Integrated genomic analyses also revealed mechanisms by which a single circadian factor controls opposing transcriptional phases. These findings shed light on the diversity and specificity of TF function in the generation of multiple phases of circadian gene transcription in a mammalian organ.
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•Enhancer activities predict circadian gene transcription in vivo•Distinct transcription factors control multiple phases of circadian gene expression•Circadian eRNAs reveal the functional component of transcription factor cistromes•A single circadian transcription factor controls opposing transcriptional phases
Enhancer RNAs reveal the functional component of transcription factor cistromes to provide global insight into the transcriptional regulation and partitioning of circadian gene expression.
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•High frequency cortical stimulation causes neurophysiological potentiation.•Low concentration propofol abolishes high frequency potentiation.•Higher concentration propofol has no ...direct cortical effect, but induces depression to high frequency stimulation.•Propofol’s amnesic effect is mediated partially by a cerebrocortical mechanism.
Propofol is well known to cause amnesia independent of its sedative effect. Memory consolidation processes in the hippocampus have been proposed as a target — however the neural substrates for propofol’s amnesic actions remain understudied and poorly described. In particular, the potential role of the cerebral cortex has not been investigated.
As an in vitro experimental model of cortical memory consolidation, potentiated cerebral cortex evoked responses were generated in mouse neocortical slices using high frequency (20 Hz) stimulation to layer IV cortical grey matter or subcortical white matter. In separate experiments, slices were pretreated with propofol at two concentrations, 2 µg/mL and 4 µg/mL, to determine the effect of clinically relevant propofol levels on the potentiation response.
Only grey matter stimulation induced a significant and lasting increase in cortical evoked potential amplitude in the drug-free condition. Propofol at 2 µg/mL completely inhibited cortical evoked response potentiation, while the 4 µg/mL concentration caused a small but significant depressant effect consequent to the high frequency stimulation.
These findings support the hypothesis that propofol disrupts memory consolidation and actively facilitates memory decay in the cerebral cortex. The results further highlight the importance of the cerebral cortex in the early phase of long term memory consolidation.
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•Rodent cortical slices generate unique excitability-dependent patterns of activity.•Activity patterns can be classified as inhibited, active and hypersynchronous.•Cortical slice ...utility depends upon understanding its functional correlates.
The ex vivo cortical slice is an extremely versatile preparation, but its utility ultimately depends on understanding its limitations and functional constraints. A question for experimentalists new to the field of cortical slice electrophysiology might be — what are the different network dynamical states available to a cortical slice as a function of excitatory drive? The purpose of this study is to provide a coherent answer to this question, within the context of extracellularly recorded population field potentials.
Cortical slices (400 µm) were prepared from adult male or female C57 mice. Evoked responses were recorded within cortical layer III/IV using extracellularly positioned metal electrodes. In the first part of the study, slice excitatory drive was increased by reducing the concentration of magnesium ions in the artificial cerebrospinal fluid — and the evoked responses categorized during the transition. In the second part, each of the identified functional states were explored in greater detail with tissue perfusion conditions and excitatory drive optimised for the requisite response state.
As expected, rodent cortical slices did not generate spontaneous, persistent EEG-like field potential activity. However, distinct response states (spontaneous and evoked) characterized by intermittent population bursts could be differentiated as a function of excitatory drive. Each state reflected different modes of neocortical activation: “monosynaptic” responses were brief, non-propagating activations, reflecting an inhibited cortex with sensory processing blocked; polysynaptic and epileptiform activity propagated intra-cortically, the latter reflecting a hyperactivated, hypersynchronous “seizing” cortex. Polysynaptic activity most closely resembled sensory “up states” associated with intracortical sensory processing.
Understanding the functional distinction between the different cortical slice response states is the starting point for designing experiments that maximise the utility of this ex vivo model. The results and descriptions in this study should help slice experimentalists less experienced in the nuances of cortical slice neurophysiology to make informed choices about how to tailor the parameters of the model to suit the specific aims of their research.
We investigate the impact of climate change on wildfire activity and carbonaceous aerosol concentrations in the western United States. We regress observed area burned onto observed meteorological ...fields and fire indices from the Canadian Fire Weather Index system and find that May–October mean temperature and fuel moisture explain 24–57% of the variance in annual area burned in this region. Applying meteorological fields calculated by a general circulation model (GCM) to our regression model, we show that increases in temperature cause annual mean area burned in the western United States to increase by 54% by the 2050s relative to the present day. Changes in area burned are ecosystem dependent, with the forests of the Pacific Northwest and Rocky Mountains experiencing the greatest increases of 78 and 175%, respectively. Increased area burned results in near doubling of wildfire carbonaceous aerosol emissions by midcentury. Using a chemical transport model driven by meteorology from the same GCM, we calculate that climate change will increase summertime organic carbon (OC) aerosol concentrations over the western United States by 40% and elemental carbon (EC) concentrations by 20% from 2000 to 2050. Most of this increase (75% for OC and 95% for EC) is caused by larger wildfire emissions with the rest caused by changes in meteorology and for OC by increased monoterpene emissions in a warmer climate. Such an increase in carbonaceous aerosol would have important consequences for western U.S. air quality and visibility.
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