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1. Neotypification for five names linked to Arenaria (Caryophyllaceae) for the endemic flora of Peru and Bolivia

   https://doi.org/10.3897/phytokeys.230.107263  

   Montesinos-Tubée, Daniel B; Iamonico, Duilio (August 2023, PhytoKeys)

   The namesArenaria mattfeldii,A. pallens,A. peruviana,A. pintaudii, andA. stuebelii(Caryophyllaceae, Arenarieae) from Peru and Bolivia were studied and neotypified based on specimens preserved at B and P. 

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2. Lattice Hamiltonian for adjoint QCD2

   https://doi.org/10.1007/JHEP08(2024)009  

   Dempsey, Ross; Klebanov, Igor R; Pufu, Silviu S; Søgaard, Benjamin T (August 2024, Journal of High Energy Physics)

   A<sc>bstract</sc> We introduce a Hamiltonian lattice model for the (1 + 1)-dimensional SU(N_c) gauge theory coupled to one adjoint Majorana fermion of massm. The discretization of the continuum theory uses staggered Majorana fermions. We analyze the symmetries of the lattice model and find lattice analogs of the anomalies of the corresponding continuum theory. An important role is played by the lattice translation by one lattice site, which in the continuum limit involves a discrete axial transformation. On a lattice with periodic boundary conditions, the Hilbert space breaks up into sectors labeled by theN_c-alityp= 0, …N_c− 1. Our symmetry analysis implies various exact degeneracies in the spectrum of the lattice model. In particular, it shows that, form= 0 and evenN_c, the sectorspandp′ are degenerate if |p−p′| =N_c/2. In theN_c= 2 case, we explicitly construct the action of the Hamiltonian on a basis of gauge-invariant states, and we perform both a strong coupling expansion and exact diagonalization for lattices of up to 12 lattice sites. Upon extrapolation of these results, we find good agreement with the spectrum computed previously using discretized light-cone quantization. One of our new results is the first numerical calculation of the fermion bilinear condensate. 

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3. Fermi isospectrality for discrete periodic Schrödinger operators

   https://doi.org/10.1002/cpa.22161  

   Liu, Wencai (September 2023, Communications on Pure and Applied Mathematics)

   Abstract Let , where , , are pairwise coprime. Let be the discrete Schrödinger operator, where Δ is the discrete Laplacian on and the potential is Γ‐periodic. We prove three rigidity theorems for discrete periodic Schrödinger operators in any dimension :If at some energy level, Fermi varieties of two real‐valued Γ‐periodic potentialsVandYare the same (this feature is referred to asFermi isospectralityofVandY), andYis a separable function, thenVis separable;If two complex‐valued Γ‐periodic potentialsVandYare Fermi isospectral and both and are separable functions, then, up to a constant, lower dimensional decompositions and are Floquet isospectral, ;If a real‐valued Γ‐potentialVand the zero potential are Fermi isospectral, thenVis zero.In particular, all conclusions in (1), (2) and (3) hold if we replace the assumption “Fermi isospectrality” with a stronger assumption “Floquet isospectrality”. 

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4. Universal Algorithms for Clustering Problems

   https://doi.org/10.1145/3572840  

   Ganesh, Arun; Maggs, Bruce M; Panigrahi, Debmalya (April 2023, ACM Transactions on Algorithms)

   This article presentsuniversalalgorithms for clustering problems, including the widely studiedk-median,k-means, andk-center objectives. The input is a metric space containing allpotentialclient locations. The algorithm must selectkcluster centers such that they are a good solution foranysubset of clients that actually realize. Specifically, we aim for lowregret, defined as the maximum over all subsets of the difference between the cost of the algorithm’s solution and that of an optimal solution. A universal algorithm’s solutionSolfor a clustering problem is said to be an α , β-approximation if for all subsets of clientsC^′, it satisfiessol(C^′) ≤ α ċopt(C′) + β ċmr, whereopt(C′ is the cost of the optimal solution for clients (C′) andmris the minimum regret achievable by any solution. Our main results are universal algorithms for the standard clustering objectives ofk-median,k-means, andk-center that achieve (O(1),O(1))-approximations. These results are obtained via a novel framework for universal algorithms using linear programming (LP) relaxations. These results generalize to other ℓ_p-objectives and the setting where some subset of the clients arefixed. We also give hardness results showing that (α, β)-approximation is NP-hard if α or β is at most a certain constant, even for the widely studied special case of Euclidean metric spaces. This shows that in some sense, (O(1),O(1))-approximation is the strongest type of guarantee obtainable for universal clustering. 

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5. Congeneric Rodents Differ in Immune Gene Expression: Implications for Host Competence for Tick‐Borne Pathogens

   https://doi.org/10.1002/jez.2908  

   Assis, Vania R; Cifarelli, Gabriella; Brehm, Allison M; Orrock, John L; Martin, Lynn B (May 2025, Journal of Experimental Zoology Part A: Ecological and Integrative Physiology)

   ABSTRACT Mice in the genusPeromyscusare abundant and geographically widespread in North America, serving as reservoirs for zoonotic pathogens, includingBorrelia burgdorferi(B. burgdorferi), the causative agent of Lyme disease, transmitted byIxodes scapularisticks. While the white‐footed mouse (Peromyscus leucopus(P. leucopus)) is the primary reservoir in the United States, the deer mouse (P. maniculatus), an ecologically similar congener, rarely transmits the pathogen to biting ticks. Understanding the factors that allow these similar species to serve as a poor and competent reservoir is critical for understanding tick‐borne disease ecology and epidemiology, especially as climate change expands the habitats where ticks can transmit pathogens. Our study investigated immunological differences between these rodent species. Specifically, we compared the expression of six immune genes (i.e., TLR‐2, IFN‐γ, IL‐6, IL‐10, GATA‐3, TGF‐β) broadly involved in bacterial recognition, elimination, and/or pathology mitigation in ear biopsies collected by the National Ecological Observatory Network (NEON) as part of their routine surveillance. A principal components analysis indicated that immune gene expression in both species varied in two dimensions: TLR2, IFN‐γ, IL‐6, and IL‐10 (comprising PC1) and TGF‐β and GATA3 (comprising PC2) expression tended to covary within individuals. However, when we analyzed expression differences of each gene singly between species,P. maniculatusexpressed more TLR2, IL‐6, and IL‐10 but less IFN‐γ and GATA3 thanP. leucopus. This immune profile could partly explain whyP. leucopusis a better reservoir for bacterial pathogens such asB. burgdorferi. 

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