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The normalization of multi-instanton effects in two-dimensional string theory involves numerical factors that are hard to determine. I'll show how they can be found using a chiral representation of the dual matrix quantum mechanics.The result is confirmed by a string field theory calculation of annuli amplitudes and nicely agrees with a median resummation of the Gamma function.

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Ref Arxiv: 2505.02572
DOI: 10.3390/e27070719
Ref. & Cit.: NASA ADS
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Mock modular forms, first invented by Ramanujan, provide a beautiful generalization of the usual modular forms. In recent years, it was found that they capture generating functions of the number of microstates of BPS black holes appearing in compactifications of string theory with 8 and 16 supercharges. This review describes these results and their applications which range from the actual computation of these generating functions for both compact and non-compact compactification manifolds (encoding, respectively, Donaldson-Thomas and Vafa-Witten topological invariants) to the construction of new non-commutative structures on moduli spaces of Calabi-Yau threefolds.

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DOI: 10.1016/j.ecss.2025.109261
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Macrophytes are a key component of lagoon ecosystems, and the spatio-temporal variation of their biomass reflects the effect of environmental drivers. Understandingthese dynamics is essential for managing, preserving and anticipating the fate of such fragile ecosystems. First, using both satellite data and field observations,we showcase here a machine learning approach to accurately detect submerged vegetation in a preserved lagoon in South France, the Bagnas lagoon. Second,we investigate the statistical relationship between the surface area of Stuckenia pectinata and abiotic factors known to influence the life history of this aquatic plant.We thus identify and evaluate the factors that most impact Stuckenia pectinata population dynamics within the lagoon. We find that water temperature, salinity, anddepth are significantly related to submerged aquatic vegetation (SAV) coverage. We show that the SAV surface area reaches a peak during summer, which can varyacross years. Furthermore, we examine the lifetime distribution of SAV during each year cycle across the pond. We show that the average annual lifespan differssignificantly from one year to the next, which can be explained by annual differences in exposure time to sufficiently high water levels.

Ref HAL: hal-04973970_v1
DOI: 10.1111/mmi.15347
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In September 2023, the Biology and Physics of Prokaryotic Chromosomes meeting ran at the Lorentz Center in Leiden, The Netherlands. As part of the workshop, those in attendance developed a series of discussion points centered around current challenges for the field, how these might be addressed, and how the field is likely to develop over the next 10 years. The Lorentz Center staff facilitated these discussions via tools aimed at optimizing productive interactions. This Perspective article is a summary of these discussions and reflects the state‐of‐the‐art of the field. It is expected to be of help to colleagues in advancing their own research related to prokaryotic chromosomes and inspiring novel interdisciplinary collaborations. This forward‐looking perspective highlights the open questions driving current research and builds on the impressive recent progress in these areas as represented by the accompanying reviews, perspectives, and research articles in this issue. These articles underline the multi‐disciplinary nature of the field, the multiple length scales at which chromatin is studied in vitro and in and highlight the differences and similarities of bacterial and archaeal chromatin and chromatin‐associated processes.

Ref HAL: hal-04953347_v1
DOI: 10.1016/j.str.2025.01.005
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Cytoskeletal-mediated membrane compartmentalization is essential to support cellular functions, from signaling to cell division, migration, or phagocytosis. Septins are cytoskeletal proteins that directly interact with membranes, acting as scaffolds to recruit proteins to cellular locations and as structural diffusion barriers. How septins interact with and remodel the lipid organization of membranes is unclear. Here, we combined minimal reconstituted systems and yeast cell imaging to study septin-mediated membrane organization. Our results show that at low concentrations membrane-diffusive septins self-assemble into sub-micrometric patches that co-exist with the septin collar at the division site. We found that patches are made of short septin filaments and that are able to modulate the lipid organization of membranes. Furthermore, we show that the polybasic domain of Cdc11 influences the membrane-organizing and curvature-sensing properties of septins. Collectively, our work provides understanding of the molecular mechanisms by which septins can support cellular functions intimately linked to membranes.

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DOI: 10.1101/2025.02.17.638629
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Ref Arxiv: 2501.14935
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We employ the renormalization group optimized perturbation theory (RGOPT) resummation method to evaluate the equation of state (EoS) for strange ($N_f=2+1$) and non-strange ($N_f=2$) cold quark matter at NLO. This allows us to obtain the mass-radius relation for pure quark stars and compare the results with the predictions from perturbative QCD (pQCD) at NNLO. Choosing the renormalization scale to generate maximum star masses of order $M=2 - 2.6 M_\odot$, we show that the RGOPT can produce mass-radius curves compatible with the masses and radii of some recently observed pulsars, regardless of their strangeness content. The scale values required to produce the desired maximum masses are higher in the strange scenario since the EoS is softer in this case. The possible reasons for such behavior are discussed. Our results also show that, as expected, the RGOPT predictions for the relevant observables are less sensitive to scale variations than those furnished by pQCD.