Dihedral Sieving Phenomena

Cyclic sieving is a well-known phenomenon where certain interesting polynomials, especially $q$-analogues, have useful interpretations related to actions and representations of the cyclic group. We propose a definition of sieving for an arbitrary group $G$ and study it for the dihedral group $I_2(n)$ of order $2n$. This requires understanding the generators of the representation ring of the dihedral group. For $n$ odd, we exhibit several instances of dihedral sieving which involve the generalized Fibonomial coefficients, recently studied by Amdeberhan, Chen, Moll, and Sagan. We also exhibit an instance of dihedral sieving involving Garsia and Haiman's $(q,t)$-Catalan numbers.Comment: 10 page

Tracking Most Significant Shifts in Nonparametric Contextual Bandits

We study nonparametric contextual bandits where Lipschitz mean reward functions may change over time. We first establish the minimax dynamic regret rate in this less understood setting in terms of number of changes $L$ and total-variation $V$, both capturing all changes in distribution over context space, and argue that state-of-the-art procedures are suboptimal in this setting. Next, we tend to the question of an adaptivity for this setting, i.e. achieving the minimax rate without knowledge of $L$ or $V$. Quite importantly, we posit that the bandit problem, viewed locally at a given context $X_t$, should not be affected by reward changes in other parts of context space $\cal X$. We therefore propose a notion of change, which we term experienced significant shifts, that better accounts for locality, and thus counts considerably less changes than $L$ and $V$. Furthermore, similar to recent work on non-stationary MAB (Suk & Kpotufe, 2022), experienced significant shifts only count the most significant changes in mean rewards, e.g., severe best-arm changes relevant to observed contexts. Our main result is to show that this more tolerant notion of change can in fact be adapted to

Learning Stress with Feet and Grids

This paper investigates quantity-insensitive stress learning using the MaxEnt learner of Pater and Prickett (2022) and compares the performance of the learner equipped with three different constraint sets: a foot-based constraint set and two grid-based constraint sets, one drawn directly from Gordon (2002), and one that changes the formulation of the main stress constraint to match the foot-based learner. The learner equipped with the foot-based constraint set succeeds at learning all the languages from the Gordon (2002) typology that it can represent; the structural ambiguity of the foot-based representations is not a problem in this regard. The foot-based learner also learns the languages as quickly in terms of number of epochs as the faster of the grid-based learners, which is the one with the revised main stress constraint. We conclude that the foot-based learner and the grid-based learner fare similarly well in this initial comparison on a typologically grounded set of learning problems

GaAs droplet quantum dots with nanometer-thin capping layer for plasmonic applications

We report on the growth and optical characterisation of droplet GaAs quantum dots with extremely-thin (11 nm) capping layers. To achieve such result, an internal thermal heating step is introduced during the growth and its role in the morphological properties of the quantum dots obtained is investigated via scanning electron and atomic force microscopy. Photoluminescence measurements at cryogenic temperatures show optically stable, sharp and bright emission from single quantum dots, at near-infrared wavelengths. Given the quality of their optical properties and the proximity to the surface, such emitters are ideal candidates for the investigation of near field effects, like the coupling to plasmonic modes, in order to strongly control the directionality of the emission and/or the spontaneous emission rate, crucial parameters for quantum photonic applications.Comment: 1 pages, 3 figure

Phytosynthesis of Silver and Gold Nanoparticles Using the Hot Water Extract of Mixed Woodchip Powder and Their Antibacterial Efficacy

This study investigates the phytosynthesis, characterization, and antibacterial efficacy of silver and gold nanoparticles (NPs) produced using the hot water extract of mixed woodchip powder. The woodchip extract (WCE) was successfully used as both a reducing and stabilizing agent for the phytosynthesis of both crystalline metal NPs. The effects of different physicochemical factors affecting the formation of the metal NPs including reaction pH, concentration of the precursor metal salts, amount of WCE, and external energy input were evaluated. The characterization of the metal NPs was performed by transmission electron microscopy, selected area electron diffraction (SAED), energy dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) pattern analysis. In addition, the antibacterial efficacy of the phytosynthesized NPs was measured. The AgNPs showed clear antibacterial activity against four representative bacterial strains. However, the AuNPs did not exhibit bactericidal activity, probably due to their surface modifications and relatively large size. These results suggest that the phytosynthesis of the metal NPs using WCE is highly efficient, and its convenience makes it suitable for use in large-scale production

Anesthetic management of non-cardiac surgery with adult onset type of cor triatriatum sinister -A case report-

A 45-year-old woman with cor triatriatum sinister was admitted for laparoscopic resection of an ovarian tumor. Her medical history was benign with the exception of a single episode of syncope one year ago. A 1.5-cm membrane fenestration was found on echocardiography, but there were no other cardiac structural anomalies. General anesthesia was established with etomidate, sevoflurane, and remifentanil; no notable events occurred during the anesthesia. As cor triatriatum shows a clinical picture of mitral stenosis (MS), careful anesthetic management is required

Music Among Friends

Program listing performers and works performe