Simultaneous in-line and off-axis subsea holographic recording of plankton and other marine particles

Optical holography provides non-intrusive, non-destructive recording of living, motile organisms and particles in their natural environment. High-resolution, three-dimensionality and 'optical sectioning' of the image allow identification of species and enumeration of size, orientation and spatial distribution. We have developed a submersible holographic camera to simultaneously expose in-line and, uniquely, off-axis holograms to record organisms from a few micrometres upwards (in-line), in concentrations down to a few tens of particles per cubic metre (off-axis). It can record up to 50 000 cm3 of the water column in a single off-axis hologram and 3500 cm3 in an in-line hologram. We describe the first sea deployment of the camera and the successful recording of holograms of plankton and marine snow to a depth of 100 m water

A holographic system for subsea recording and analysis of plankton and other marine particles (HOLOMAR)

We report here details of the design, development, initial testing and field-deployment of the HOLOMAR system for in-situ subsea holography and analysis of marine plankton and nonliving particles. HOLOMAR comprises a submersible holographic camera ("HoloCam") able to record in-line and off-axis holograms at depths down to 100 m, together with specialised reconstruction hardware ("HoloScan") linked to custom image processing and classification software. The HoloCam consists of a laser and power supply, holographic recording optics and holographic plate holders, a water-tight housing and a support frame. It utilises two basic holographic geometries, in-line and off-axis such that a wide range of species, sizes and concentrations can be recorded. After holograms have been recorded and processed they are reconstructed in full three-dimensional detail in air in a dedicated replay facility. A computer-controlled microscope, using video cameras to record the image at a given depth, is used to digitise the scene. Specially written software extracts a binarised image of an object in its true focal plane and is classified using a neural network. The HoloCam was deployed on two separate cruises in a Scottish sea loch (Loch Etive) to a depth of 100 m and over 300 holograms were recorded

Organisational problems in respect of the implementation of activity‐based costing in South Africa

In this study the extent and nature of organisational problems that are encountered in South Africa in respect of the implementation of activitybased costing are examined and compared with difficulties experienced by companies in the British Isles, United States of America and Australia. The investigation comprised a literature survey as well as an empirical study of the companies listed in South Africa. Contrary to the findings of overseas studies, South African companies experience less difficulty in respect of support from senior management and considere the employee resources allocated to the ABC projects to be adequate and satisfactory. ABC objectives are aligned with organisational goals, culture and company strategy. However, whilst implementers are adequately trained, the insufficient training of users and managers is perceived to be a hindrance to success and in the majority of companies other priorities take precedence to the ABC project

Adeno-associated virus 2 infection in children with non-A–E hepatitis

An outbreak of acute hepatitis of unknown aetiology in children was reported in Scotland1 in April 2022 and has now been identified in 35 countries2. Several recent studies have suggested an association with human adenovirus with this outbreak, a virus not commonly associated with hepatitis. Here we report a detailed case–control investigation and find an association between adeno-associated virus 2 (AAV2) infection and host genetics in disease susceptibility. Using next-generation sequencing, PCR with reverse transcription, serology and in situ hybridization, we detected recent infection with AAV2 in plasma and liver samples in 26 out of 32 (81%) cases of hepatitis compared with 5 out of 74 (7%) of samples from unaffected individuals. Furthermore, AAV2 was detected within ballooned hepatocytes alongside a prominent T cell infiltrate in liver biopsy samples. In keeping with a CD4+ T-cell-mediated immune pathology, the human leukocyte antigen (HLA) class II HLA-DRB1*04:01 allele was identified in 25 out of 27 cases (93%) compared with a background frequency of 10 out of 64 (16%; P = 5.49 × 10−12). In summary, we report an outbreak of acute paediatric hepatitis associated with AAV2 infection (most likely acquired as a co-infection with human adenovirus that is usually required as a ‘helper virus’ to support AAV2 replication) and disease susceptibility related to HLA class II status. © 2023, The Author(s), under exclusive licence to Springer Nature Limited