Molecular phylogenetic markers used to be ubiquitously obtained by Sanger sequencing, while recently, next generation sequencing (NGS) approaches have become popular alternatives. In this study, a pipeline utilizing Oxford Nanopore Technologies (ONT) amplicon sequencing (amplicon-seq) was examined as an alternative to Sanger sequencing, with nine loci [11 polymerase chain reaction (PCR) products], in Aeschynanthus (Gesneriaceae). Pooled PCR products for each species were sequenced on an ONT MinION system. For scalability and ease of consensus sequence acquisition, a python 'snakemake' bioinformatic pipeline, 'petithebi' (small snake), was designed. To assess the required minimum coverage, we simulated various coverage levels by using different numbers of input reads and found no nucleotide polymorphisms, but a few indels at polymononucleotide sites at low coverage. When comparing ONT amplicon-seq with Sanger sequencing, only two out of 81 sequences differed, involving one nucleotide change and one indel, demonstrating a very high reproducibility between the two methods. Thus, ONT amplicon-seq is a suitable alternative for Sanger sequencing to obtain molecular markers, also allowing Sanger legacy data to be combined with NGS-derived ONT amplicon-seq data. The 'petithebi' pipeline is also a useful tool to ease the transition from Sanger sequencing to NGS, where a high demand of bioinformatic skill is often a barrier.
We report on the cosmic ray mass composition measured by the Telescope Array Low-energy Extension (TALE) hybrid detector. The TALE detector consists of a fluorescence detector (FD) station with 10 FD telescopes located at the Telescope Array (TA) Middle Drum FD Station (itself made up of 14 FD telescopes), and a surface detector (SD) array of scintillators. The array consists of 40 SDs with 400 m spacing and 40 SDs with 600 m spacing. In this paper, we present results on the measurement of the depth of shower maxima (Xmax) in the energy range from 1016.5 eV to 1018.5 eV collected over five years of the TALE hybrid detector. The Xmax distributions were analyzed and compared with Monte Carlo simulations of proton, helium, nitrogen, and iron primaries, using the QGSJet II-04 hadronic interaction model. Our results indicate that the elongation rate of the mean Xmax, which is defined as the slope of KXmaxi versus cosmic ray energy, exhibits a break around 1017 eV. Up to this energy, the composition becomes increasingly heavy, characterized by a growing dominance of heavy nuclei and a steadily decreasing fraction of light primaries. Beyond this energy, the proton fraction increases significantly with energy. These findings suggest a transition from Galactic to extra-Galactic cosmic ray sources around the so-called second knee.
We report the first successful formation of inversion doping in diamond achieved by ion implantation, realizing conductivity conversion from n-type to p-type. Type Ib diamond containing nitrogen donors ( similar to 3.3 & times; 10(19) cm(-3)) was implanted with boron ions at multiple energies (5-200 keV) to achieve a uniform depth profile up to similar to 400 nm. The implantation was performed with boron concentrations ranging from 2 & times; 10(19) to 3.5 & times; 10(20) cm(-3), followed by high-temperature annealing. Electrical characterization revealed a transition from n-type to p-type conduction as the boron concentration exceeded the nitrogen donor level in the substrate. The heavily implanted sample (3.5 & times; 10(20) cm(-3)) exhibited p-type behavior with a sheet resistance of 4 & times; 10(4) Omega/square at room temperature and an activation energy of 0.06 eV. This achievement represents the first demonstration of the conduction-type inversion in diamond by ion implantation, establishing a viable approach to locally form p-n junctions in the n-well region. The ability to locally form p-type regions within a nitrogen-rich diamond provides a decisive step toward complementary diamond transistor devices, proving that ion implantation doping is a practical and controllable method for realizing various diamond devices.
We demonstrated the formation of a donor band even in Si quantum dots (Si-QDs) with fewer than ten donors. Hot P+-ions were implanted at 800 degrees C into Si-QDs fabricated by implanting hot Si+ ions into a SiO2 layer. After post-N-2 annealing at 1000 degrees C, the P+-doped Si-QDs with a diameter of 2.5 nm were embedded into the SiO2 layer. The P+-ion dose (D-P) varied from 1 & times; 10(15) to 9 & times; 10(15) cm(-2). Energy-dispersive x-ray spectroscopy revealed that the implanted P atoms clustered in the Si-QDs, which led to the experimental verification of the co-clustering of hot Si+/P+-ion implantation. Thus, the DP dependence of the P-atom concentration (NP-EDX) in Si-QDs was accurately determined. Additionally, the P 1s spectrum obtained by hard x-ray photoelectron spectroscopy revealed that the P-Si bond of the P-doped Si-QDs, including substantial P atoms, directly verifies donor formation in the Si-QDs. The upper limit of activation rate R-ACT(UP) of the implanted P atoms in the Si-QDs was obtained by the P-Si bond ratio. Therefore, the upper limit of donor concentration in the Si-QDs (N-D(UP)) was determined by N-D(UP) =NP-EDX & times; R-ACT(UP), resulting in 1.4 & times; 1020 <= N-D(UP) <= 1.3 & times; 10(21) cm(-3). The upper limit of number of donors in the Si-QDs (n(D)(UP)) was overestimated to be between 1 and 12. Additionally, the photoluminescence revealed the bandgap EG narrowing (Delta EG), even in the Si-QDs with n(D)(UP) < 12 caused by donor band tailing. Delta EG was much lower than those of two- and three-dimensional Si.
The 11-yr variation of galactic cosmic-ray flux lags behind the variation of the sunspot number. An average ~1-yr time-lag is expected from the outward propagating solar wind with the frozen-in photospheric magnetic field varying in the solar cycle, and from the inward diffusive transport of cosmic-ray particles. The long-term neutron monitor data, however, show that the time-lag is significantly longer (shorter) in the odd (even) solar cycle. In this paper, we analyze the time-lag in proton and electron fluxes observed by the CALET. It is found that the time-lag is similar in proton and electron fluxes during an A > 0 polarity epoch of the solar dipole magnetic field. In an even solar cycle 24 including a polarity reversal from A < 0 to A > 0, on the other hand, it is found that the time-lag of proton (electron) flux variation is significantly shorter (longer) than the average ~1-yr lag by analyzing the combined data with CALET and AMS-02. This is the first observation of the charge-sign dependent time-lag. We demonstrate that these observations can be qualitatively interpreted in terms of different 11-yr time profiles of proton and electron fluxes in A > 0 and A < 0 epochs expected from the drift effect.
