Hokkaido Research Organization

Impact of artificial stocking and its intensity on genetic diversity, genetic structure, and effective number of breeders in masu salmon Oncorhynchus masou

Artificial stocking, an important tool in fishery resource enhancement and wildlife management, exerts negative effects on wild conspecifics. However, the factors determining the magnitude of these effects remain unclear. Here, we investigated how stocking influences genetic dive...

Explicit Right-Kernel Supports in Two-Prime Rédei Layers: An r4=1 Criterion and Conditional CFRAC Redundancy

We give an explicit treatment of right-kernel supports in two-prime pure Rédei layers for discriminants D = 4Ap1p2, with emphasis on the case r4 = 1. A unified four-bit formula describes the column-normalized 4-by-4 Rédei matrix, and an exhaustive classification identifies the no...

Shaped Heights on Pell Unit Orbits: Monotone Dynamics, Depth Recovery, and Sharp Small-Height Bounds

Let N = ℓM ≡ 3 (mod 4) be the product of distinct odd primes 3 ≤ ℓ < M, and let a₀ = floor(√N). We study positive integral solutions X² − Ny² = σcℓ, X = a₀y + t, where c ∈ {1,2}. A description by the height t alone is not valid: multiplication by the positive fundamental unit pre...

Shaped Heights on Pell Unit Orbits: Monotone Dynamics, Depth Recovery, and Sharp Small-Height Bounds

Let N = ℓM ≡ 3 (mod 4) be the product of distinct odd primes 3 ≤ ℓ < M, and put a₀ = ⌊√N⌋. We study positive integral solutions of X² − Ny² = σcℓ, X = a₀y + t, where c ∈ {1,2}. A description by the height t alone is not valid: multiplication by the positive fundamental unit prese...

Unconditional Half-Density at Minimum 2-Class Depth in a Two-Prime Layer III+ Family

We prove unconditionally that the minimum-depth event (e=2) has limiting conditional density (1/2) in a two-prime Layer III+ family. The Layer III+ character sum is decomposed into four components. Three ancillary components are realized as tempered quadratic or cyclic-quartic ch...

Explicit 8-Rank Criteria in a Squarefree Composite Family: Rédei Kernels, Artin Symbols, and Continued-Fraction Centers

We study the narrow class group of real quadratic fields with fundamental discriminant D = 4AB, where A is a prime congruent to 7 modulo 8 and B = p₁p₂ is a product of two distinct primes lying either both in 1 modulo 8 or both in 7 modulo 8. A single four-bit formula is obtained...

An eigenvalue decomposition based full polarimetric SAR framework for leaf area index retrieval using entropy-anisotropy features

Present study proposes a novel Full Polarimetric Radar Vegetation Index (FPRVI) for accurate Leaf Area Index (LAI) retrieval using RISAT-1A full-polarimetric SAR data. The eigenvalue-based polarimetric decomposition parameters entropy (H) and anisotropy (A) have been employed to...

The Jacobi-positive squarefree odd semiprimes: a complete parametrisation

Let N = ℓM with 3 ≤ ℓ < M distinct odd primes and let 𝒥(N) be the set of denominators Q_k in the period of the continued fraction of √N whose Jacobi symbol (Q_k/N) equals +1. A previous paper (DOI 10.5281/zenodo.21285697) proved that 𝒥(N) = {1} forces the period length L to lie i...