Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Индивидуальность поведения рыб влияет на риск заражения паразитами [Personality influences risk of parasitism in fish]

Influence of fish personality on infection rate is almost not studied. In the experiments on the young-of-the-year Oncorhynchus mykiss and cercariae of a trematode Diplostomum pseudospathaceum we tested the hypothesis that infection rate differs between more and less active (“bold” and “shy”) fish. Will individual differences in infection persist upon re-infection? Fish serve as a second intermediate host for this trematode. A positive correlation was found between the results of consecutive infections. Accumulation of parasites with successive infections leads to an aggregated distribution of D. pseudospathaceum among the hosts, affecting individual fitness and polymorphism in fish populations. Persistent individual differences in parasite burden among fish and, as a result, vulnerability for predators confirms the role of parasites as an important factor of natural selection.peerReviewe

Cerium-doped gadolinium-scandium-aluminum garnet powders: synthesis and use in X-ray luminescent diamond composites

Powders of single-phase solid solutions based on cerium-doped gadolinium-scandium-aluminum garnet were synthesized by coprecipitation from aqueous solutions followed by annealing at 1600 °C. The solubility limit of cerium in gadolinium-scandium-aluminum garnet was determined by X-ray powder diffraction and scanning electron microscopy. It has been demonstrated that the solubility limit of cerium depends not only on the concentration of scandium in the solid solution but also on the fraction of Sc3+ cations in the dodecahedral and octahedral positions of the garnet crystal lattice. Based on the X-ray luminescence spectra of Ce3+ (∼575 nm, 5d→4f transition) in single-phase samples, the composition (Gd2.73Ce0.02Sc0.5Al4.75O12) with the highest X-ray luminescence was determined. A diamond composite “Diamond-GSAG:Ce” with Gd2.73Ce0.02Sc0.5Al4.75O12 particles has been fabricated, which exhibits intense yellow X-ray luminescence, that is visible to the eye. The investigated class of composites is promising for applications in stable detectors and visualizers of high-intensity X-ray radiation in synchrotrons and free-electron lasers

Behavioural adaptations of argulid parasites (Crustacea: Branchiura) to major challenges in their life cycle

Fish lice (Argulus spp.) are obligate ectoparasites, which contrary to most aquatic parasites, retain the ability to swim freely throughout the whole of their life. In fish farms, they can quickly increase in numbers and without effective control cause argulosis, which results in the reduced growth and survival of their fish hosts. The morphology of Argulus spp, including their sensory organs, is suitable for both parasitism and free-swimming. By spending a considerable amount of time away from their host, these parasites risk being excessively dispersed, which could endanger mating success. Here we present a review of recent studies on the behaviour of Argulus spp, especially the aggregative behaviour that mitigates the dilution of the parasite population. Aggregation of parasites, which is especially important during the period of reproduction, occurs on different scales and involves both the aggregation of the host and the aggregation of the parasites on the host. The main behavioural adaptations of Argulus spp, including searches for hosts and mates, host manipulation and host choice, are all focused on the fish. As these ectoparasites repeatedly change hosts and inflict skin damage, they can act as vectors for fish pathogens. The development of environmentally friendly measures for the control and prevention of argulosis needs to take into account the behaviour of the parasites.peerReviewe