Tootfinder

For running my #HamRadio portable setup from solar power, I made a power distribution box. I didn't know where to stop, apparently, and now I have a beast that weighs 1.2kg. It has two isolated battery busses, each of which has an XT60M, PowerPole, and 5.5x2.1mm barrel connector to choose from, supporting the batteries I have and that friends might have. It has four other circuits that …

#PrettyFlyForAWiFi

Polycyclic aromatic hydrocarbon (PAH) abundances in the disk around T Chamaeleontis (T Cha): PAH sizes, ionization fraction, and mass during JWST observations
Rahul Bandyopadhyay (Departamento de Astronom\'ia, Universidad de Chile, Santiago, Chile, Millennium Nucleus on Young Exoplanets and their Moons), Simon Casassus (Departamento de Astronom\'ia, Universidad de Chile, Santiago, Chile, Data Observatory Foundation, Santiago, Chile)

Polycyclic aromatic hydrocarbon (PAH) abundances in the disk around T Chamaeleontis (T Cha): PAH sizes, ionization fraction, and mass during JWST observations
The T Tauri star T Cha is known to have a protoplanetary disk with a dust gap separating the inner and outer disk regions. The mid-IR JWST spectrum of T Cha show multiple prominent aromatic infrared bands (AIBs) around 6.2, 8.1, and 11.3 $μ$m. AIBs are commonly accepted as the emission stemming from PAH molecules. We aim to characterize the PAHs giving rise to the AIBs observed in the JWST spectrum of T Cha. Our objective is to estimate the PAH abundances, in terms of their sizes, ionization f…

Poset-enriched pretoposes and compact ordered spaces
J\'er\'emie Marqu\`es, Luca Reggio
https://arxiv.org/abs/2508.09944 https://arxiv.org/pdf/2508…

Poset-enriched pretoposes and compact ordered spaces
We provide a characterisation of the category $\mathsf{KOrd}$ of Nachbin's compact ordered spaces as a poset-enriched category. Up to equivalence, $\mathsf{KOrd}$ is the only non-degenerate poset-enriched pretopos whose terminal object is a (discrete) generator and in which every object is covered by an order-filtral object. Order-filtral objects satisfy an appropriate form of compactness and separation. Throughout, we make extensive use of the internal language of poset-enriched pretoposes.

Deep Reinforcement Learning in Factor Investment
Junlin Liu
https://arxiv.org/abs/2509.16206 https://arxiv.org/pdf/2509.16206

Deep Reinforcement Learning in Factor Investment
Deep reinforcement learning has shown promise in trade execution, yet its use in low-frequency factor portfolio construction remains under-explored. A key obstacle is the high-dimensional, unbalanced state space created by stocks that enter and exit the investable universe. We introduce Conditional Auto-encoded Factor-based Portfolio Optimisation (CAFPO), which compresses stock-level returns into a small set of latent factors conditioned on 94 firm-specific characteristics. The factors feed a D…

Observational Constraints on Evolution of Dust Disc Properties in Upper Scorpius
Paola Pinilla, Anibal Sierra, Nicolas T. Kurtovic, Rossella Anania, Sean Andrews, John Carpenter, Osmar Guerra-Alvarado, Feng Long, Sebastian Marino, Miguel Vioque, Ke Zhang
https://arxiv.org/abs/2509.19442

Observational Constraints on Evolution of Dust Disc Properties in Upper Scorpius
Protoplanetary discs in the Upper Scorpius star-forming region are excellent laboratories to investigate late stages of planet formation. In this work, we analyse the morphology of the dust continuum emission of 121 discs from an ALMA Band 7 survey of the Upper Scorpius region. This analysis is done in the visibility plane, to measure the flux, geometry and characterise potential structures. We compare the results with state-of-the art gas and dust evolution models that include external photoev…

Variable selection for minimum-variance portfolios
Guilherme V. Moura, Andr\'e P. Santos, Hudson S. Torrent
https://arxiv.org/abs/2508.14986 https://ar…

Variable selection for minimum-variance portfolios
Machine learning (ML) methods have been successfully employed in identifying variables that can predict the equity premium of individual stocks. In this paper, we investigate if ML can also be helpful in selecting variables relevant for optimal portfolio choice. To address this question, we parameterize minimum-variance portfolio weights as a function of a large pool of firm-level characteristics as well as their second-order and cross-product transformations, yielding a total of 4,610 predicto…

Next-generation soliton frequency combs in photonic-crystal and nanocomposite microresonators
Haixin Liu, Alexa Carollo, Jizhao Zang, Scott B. Papp
https://arxiv.org/abs/2508.13393

Next-generation soliton frequency combs in photonic-crystal and nanocomposite microresonators
Microresonator frequency combs offer tremendous opportunity to advance applications in fundamental research and technology by linking the optical and microwave frequency domains. Kerr-nonlinear microresonators further enable the generation of portable, integrated optical frequency combs, which are called microcombs. However, the dispersion engineering usually suffers from the small, geometric parameter space, and achieving soliton microcombs is challenging and usually requires complicated exper…

The Interplay between Utility and Risk in Portfolio Selection
Leonardo Baggiani, Martin Herdegen, Nazem Khan
https://arxiv.org/abs/2509.10351 https://arxiv…

The Interplay between Utility and Risk in Portfolio Selection
We revisit the problem of portfolio selection, where an investor maximizes utility subject to a risk constraint. Our framework is very general and accommodates a wide range of utility and risk functionals, including non-concave utilities such as S-shaped utilities from prospect theory and non-convex risk measures such as Value at Risk. Our main contribution is a novel and complete characterization of well-posedness for utility-risk portfolio selection in one period that takes the interplay betw…

Revisiting the maximum mass limit of strange stars in higher-order curvature-matter coupled gravity
Debadri Bhattacharjee, Pradip Kumar Chattopadhyay
https://arxiv.org/abs/2508.10524

Revisiting the maximum mass limit of strange stars in higher-order curvature-matter coupled gravity
We explore the maximum mass limit of strange stars within the framework of modified gravity described by $f(\tilde{R},T)=R+αR^{2}+2βT$, where $R$ is the Ricci scalar and $T$ denotes the trace of the energy-momentum tensor. The parameters $α$ and $β$ characterise the contributions from higher-order curvature terms and the coupling between matter and geometry, respectively. By deriving the Tolman-Oppenheimer-Volkoff equations from the modified field equations and applying the MIT bag model eq…