Cytogenetic characterization of Taphronota thaelephora Stal. 1873. (Orthoptera: Pyrgomorphidae) from Cameroon. II. Description of mitotic chromosomes

Taphronota thaelephora Stal. 1873 is generating a lot of interest for biological and cytogenetic studies because it has demonstrated the potential for a future veritable pest in Cameroon. The lack of previouslyestablished karyotype for the species has necessitated this study. Testes from five adult individuals collected from Balepa - Mbouda in the West Region of Cameroon and treated with 1% colchicine were analyzed usingthe Lactic-Propionic Orcein squash technique. Mitotic metaphase chromosomes were measured directly from the microscope and pictures taken with the help of the Lietz photomicroscope. Pictures were processed with the Microsoft Office Picture Manager. The species revealed the standard Pyrgomorphidae karyotype of 2n‰= 19 acrocentric chromosomes. Mean length of the chromosomes ranged from 8.10}1.7 to 3.75}0.0 ƒÊm. Analysis of Relative Chromosome Lengths (RCL) revealed three distinct size groups of long, medium and short. The karyotype of T. thaelephora was made up of 2 pairs of long chromosomes (2LL) and the X-chromosome, 6 pairs of medium chromosomes (6MM) and 1 pair of short chromosomes (1SS). The mean lengths of the long, medium and short sized chromosomes were 7.2 ƒÊm, 4.8 ƒÊm and 3.51 ƒÊm respectively. The X-chromosome was the shortest of the large chromosomes with a mean length of 6.75 ƒÊm

Field excursion to enhance coastal and environmental engineering capacities of engineers in administrative positions

The capacity building of coastal administrators is essential for sustainable coastal zone management. In order to enhance the ability of trainees in coastal and environmental engineering, the College of Land, Infrastructure, Transport and Tourism of the Japanese Government has carried out annual field excursions to Kujukuri Beach, a typical sandy beach in central Japan for comprehensively learning about real phenomena occurring on the beach and in the hinterland. This paper describes the excursion in 2011, in which 20 trainees participated. The importance of learning through the field excursions to coasts is discussed

Search for Axion like particles using Laue-case conversion in a single crystal

Axion Like Particles (ALPs) with a sub-keV range mass are searched by using the light-shining-through-a-wall technique. A novel system is developed in which injected X rays are converted and reconverted by the Laue-case conversion within a silicon single crystal with dual blades. The resonant ALPs' mass of the conversion is scanned by varying the X-ray injection angle to the crystal. No significant signals are observed, and 90% C. L. upper limits on the ALP-two photon coupling constant are obtained as follows, g_{a\gamma\gamma} < 4.2 \times 10^{-3} GeV^{-1} (m_a < 10 eV), g_{a\gamma\gamma} < 5.0 \times 10^{-3} GeV^{-1} (46 eV < m_a < 1020 eV). These are the most stringent laboratorial constraints on ALPs heavier than 300 eV.Comment: 13 pages, 5 figures, 1 tabl

Search for Dark Photon Dark Matter in the Mass Range 74-110 μeV with a Cryogenic Millimeter-Wave Receiver

ミリ波を用いたダークマター探索手法を確立. 京都大学プレスリリース. 2023-03-07.Thinking big and dark by starting small and light: Millimeter-wave technologies assist in examining 'light' dark matter. 京都大学プレスリリース. 2023-03-23.We search for the dark photon dark matter (DPDM) using a cryogenic millimeter-wave receiver. DPDM has a kinetic coupling with electromagnetic fields with a coupling constant of χ and is converted into ordinary photons at the surface of a metal plate. We search for signal of this conversion in the frequency range 18-26.5 GHz, which corresponds to the mass range 74-110 μeV/c². We observed no significant signal excess, allowing us to set an upper bound of χ<(0.3-2.0)×10⁻¹⁰ at 95% confidence level. This is the most stringent constraint to date and tighter than cosmological constraints. Improvements from previous studies are obtained by employing a cryogenic optical path and a fast spectrometer