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JWST Discovery of Microlensed Stars in a Magnified Galaxy, the "Dragon" behind Abell 370
No full textInternational audienceStrong gravitational magnification by massive galaxy clusters enable us to detect faint background sources, resolve their detailed internal structures, and in the most extreme cases identify and study individual stars in distant galaxies. Highly magnified individual stars allow for a wide range of applications, including studies of stellar populations in distant galaxies and constraining small-scale dark matter structures. However, these applications have been hampered by the small number of events observed, as typically one or a few stars are identified from each distant galaxy. Here, we report the discovery of 46 significant microlensed stars in a single strongly-lensed high-redshift galaxy behind the Abell 370 cluster at redshift of 0.725 when the Universe was half of its current age (dubbed the ``Dragon arc''), based on two observations separated by one year with the James Webb Space Telescope ({\it JWST}). These events are mostly found near the expected lensing critical curves, suggesting that these are magnified individual stars that appear as transients from intracluster stellar microlenses. Through multi-wavelength photometry and colors, we constrain stellar types and find that many of them are consistent with red giants/supergiants magnified by factors of thousands. This finding reveals an unprecedented high occurrence of microlensing events in the Dragon arc, and proves that {\it JWST}'s time-domain observations open up the possibility of conducting statistical studies of high-redshift stars and subgalactic scale perturbations in the lensing dark matter field
Bivariate polynomial reduction and elimination ideal over finite fields
No full textInternational audienceGiven two polynomials a and b in Fq[x,y] which have no non-trivial common divisors, we prove that a generator of the elimination ideal ⟨a, b⟩ ∩ Fq [x] can be computed in quasi-linear time. To achieve this, we propose a randomized algorithm of the Monte Carlo type which requires (de log q)1+o(1) bit operations, where d and e bound the input degrees in x and in y respectively.The same complexity estimate applies to the computation of the largest degree invariant factor of the Sylvester matrix associated with a and b (with respect to either x or y), and of the resultant of a and b if they are sufficiently generic, in particular such that the Sylvester matrix has a unique non-trivial invariant factor.Our approach is to exploit reductions to problems of minimal polynomials in quotient algebras of the form Fq [x, y]/⟨a, b⟩. By proposing a new method based on structured polyno- mial matrix division for computing with the elements of the quotient, we succeed in improving the best-known complexity bounds
The open XYZ spin 1/2 chain: Separation of Variables and scalar products for boundary fields related by a constraint
No full textInternational audienceWe consider the open XYZ spin chain with boundary fields. We solve the model by the new Separation of Variables approach introduced in arXiv:1904.00852. In this framework, the transfer matrix eigenstates are obtained as a particular sub-class of the class of so-called separate states. We consider the problem of computing scalar products of such separate states. As usual, they can be represented as determinants with rows labelled by the inhomogeneity parameters of the model. We notably focus on the special case in which the boundary parameters parametrising the two boundary fields satisfy one constraint, hence enabling for the description of part of the transfer matrix spectrum and eigenstates in terms of some elliptic polynomial Q-solution of a usual TQ-equation. In this case, we show how to transform the aforementioned determinant for the scalar product into some more convenient form for the consideration of the homogeneous and thermodynamic limits: as in the open XXX or XXZ cases, our result can be expressed as some generalisation of the so-called Slavnov determinant
De Merlin à Merlot. Le devenir de l'enchanteur dans les récits brefs en vers des XIIIe et XIVe siècles [version en japonais uniquement]
No full textInternational audienc
Life Cycle Assessment of Concrete Recycling Solutions in Light of Their Technical Complexity
No full textInternational audienceWaste management is a key step for addressing both the environmental impact and the growing demand for resources in the construction industry. To answer these challenges, various technologies are available, carrying different environmental impacts and sociotechnical implications. For concrete waste, recycling is the most common solution. Two main recycling roads were identified, leading to products that have low or high value and implying different technical developments and environmental impacts. This study first proposed to characterize recycling technologies by their technical degree, reflecting the complexity needed to process waste. It secondly compared their environmental impacts using LCA methodology to assess which technical complexity led to minor environmental consequences and under what conditions. The results revealed that the technologies with a low technical degree tended to have a lower environmental impact than the ones with a higher technical degree when only the generated impacts were considered. The reverse was observed when considering the aggregated impacts due to the environmental benefits provided by the potentially avoided products
Intranasally administrated fusion-inhibitory lipopeptides block SARS-CoV-2 infection in mice and enable long-term protective immunity
No full textInternational audienceAbstract We have assessed antiviral activity and induction of protective immunity of fusion-inhibitory lipopeptides derived from the C-terminal heptad-repeat domain of SARS-CoV-2 spike glycoprotein in transgenic mice expressing human ACE2 (K18-hACE2). The lipopeptides block SARS-CoV-2 infection in cell lines and lung-derived organotypic cultures. Intranasal administration in mice allows the maintenance of homeostatic transcriptomic immune profile in lungs, prevents body-weight loss, decreases viral load and shedding, and protects mice from death caused by SARS-CoV-2 variants. Prolonged administration of high-dose lipopeptides has neither adverse effects nor impairs peptide efficacy in subsequent SARS-CoV-2 challenges. The peptide-protected mice develop cross-reactive neutralizing antibodies against both SARS-CoV-2 used for the initial infection and recently circulating variants, and are completely protected from a second lethal infection, suggesting that they developed SARS-CoV-2-specific immunity. This strategy provides an additional antiviral approach in the global effort against COVID-19 and may contribute to development of rapid responses against emerging pathogenic viruses
Delivery of Prime editing in human stem cells using pseudoviral NanoScribes particles
No full textInternational audienc
Un sens littéral de l'Apocalypse ? L'Apocalypse avec une explication tirée des Saints Pères et des auteurs ecclésiastiques (1702)
No full textHIV Vpr activates a nucleolar-specific ATR pathway to degrade the nucleolar stress sensor CCDC137
No full textThe lentiviral accessory protein Vpr engages an extensive network of cellular pathways to drive diverse host consequences. Of its many phenotypes, CRL4A-E3 ubiquitin ligase complex co-option, DNA damage response (DDR) engagement, and G2/M arrest are conserved and thus proposed to be functionally important. How Vpr effects these functions and whether they explain how Vpr dysregulates additional cellular pathways remain unclear. Here we leverage the ability of Vpr to deplete the nucleolar protein CCDC137 to understand how Vpr-induced DDR activation impacts nucleolar processes. We characterize CCDC137 as an indirect Vpr target whose degradation does not correlate with Vpr-induced G2/M arrest. Yet, degradation is conserved among Vpr from the pandemic HIV-1 and related SIVcpz/SIVgor, and it is triggered by genomic insults that activate a nucleolar ATR pathway in a manner similar to camptothecin. We determine that Vpr causes ATR-dependent features of nucleolar stress that correlate with CCDC137 degradation, including redistribution of nucleolar proteins, altered nucleolar morphology, and repressed ribosome biogenesis. Together, this data distinguishes CCDC137 as a non-canonical Vpr target that may serve as a sensor of nucleolar disruption, and in doing so, identifies a novel role for Vpr in nucleolar stress
Divergent responses to SARS-CoV-2 infection in bronchial epithelium with pre-existing respiratory diseases
No full textInternational audiencePre-existing respiratory diseases may influence coronavirus disease (COVID-19) susceptibility and severity. However, the molecular mechanisms underlying the airway epithelial response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection severity in patients with chronic respiratory diseases remain unelucidated. Using an in vitro model of differentiated primary bronchial epithelial cells, we aimed to investigate the molecular mechanisms of SARS-CoV-2 infection in pre-existing cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Our study revealed reduced susceptibility of CF and COPD airway epithelia to SARS-CoV-2, relative to that in healthy controls. Mechanistically, reduced transmembrane serine protease 2 (TMPRSS2) activity potentially contributed to this resistance of CF epithelium. Upregulated complement and inflammatory pathways in CF and COPD epithelia potentially primed the antiviral state prior to infection. Analysis of a COVID-19 patient cohort validated our findings, correlating specific inflammatory markers (IP-10, SERPINA1, and CFB) with COVID-19 severity. This study elucidates SARS-CoV-2 pathogenesis and identifies potential biomarkers for clinical monitoring