Geometric and wave optics in a BTZ optical metric-based wormhole

We investigate the geometric and wave optical properties of a (2+1)-dimensional ultra-static spacetime conformally related to the static BTZ black hole, characterized by constant negative Gaussian curvature. The associated optical metric defines a hyperbolic wormhole geometry, wherein null geodesics experience a Pöschl–Teller-type repulsive effective potential that suppresses circular photon orbits and directs all trajectories toward the optical origin. In the wave regime, we reformulate the Helmholtz equation into a Schrödinger-like form, revealing a spatially localized effective potential that encodes curvature and angular momentum effects. The resulting refractive index n(ρ,ω)n(\rho,\omega)&nbsp;is both spatially and spectrally dispersive, leading to a position-dependent critical frequency ωc(ρ)\omega_c(\rho)&nbsp;that delineates the boundary between propagating and evanescent modes. At high frequencies, the medium becomes asymptotically transparent, while for ω&lt;ωc(ρ)\omega &lt; \omega_c(\rho), waves undergo exponential attenuation. These results demonstrate intrinsic curvature-induced spectral filtering and provide a geometrically tunable framework for analog gravity systems and graphene-based photonic platforms.</p

Embryogenesis and early larval development in rosy barb (Pethia conchonius, Hamilton 1822)

This study aimed to investigate the larval ontogeny of rosy barb Pethia conchonius (Hamilton 1822). Embryonic and larval development stages were studied using the microscopy technique. Trials were carried out on 60 broodstock of rosy barb. Round and transparent fertilized eggs with a diameter of 867.6 ± 21.7 µm have started to hatch approximately 27 h after spawning at 26.3°C. The newly hatched larvae (n:30) have a mean total length of 4227 ± 265 µm and started exogenous feeding 4 days after hatching (DAH) and started taking particulate and powder feed at the end of 18 DAH. The early development growth formula of rosy barb has an exponential relationship model of y = 3.8346e0.0313x (R2 = 0.9112, n = 140). Digestive tract differentiation, hepatopancreas, digestive tubes, and gill arches formations were examined by taking histological sections in the early life stages of the rosy barb. Rosy barb is a species whose production protocol is not difficult due to its short egg hatching period and early larval stage zooplankton feeding period