Could virtual reality applications pose real risks to children and adolescents? A systematic review of ethical issues and concerns.

Virtual reality technologies (VRTs) are high-tech human-computer interfaces used to develop digital content and can be applied to multiple different areas, often offering innovative solutions to existing problems. A wide range of digital games is being also developed with VRTs and together with their components, the games' structural elements are appealing to children and engaging them more in virtual worlds. Our research interest is directed towards children's development and the effects of VRTs within gaming environments. Contemporary psychology studies perceive human development as a holistic and lifelong process with important interrelationships between physical, mental, social and emotional aspects. For the objectives and scope of this work, we examine children development across three domains: physical, cognitive and psychosocial. In this context, the authors review the literature on the impact of VRTs on children, in terms of software and hardware. Since research requires an wide-ranging approach, we study the evidence reported on the brain and neural structure, knowledge, behaviour, pedagogy, academic performance, and wellness. Our main concern is to outline the emerging ethical issues and worries of parents, educators, ophthalmologists, neurologists, psychologists, paediatricians and all relevant scientists, as well as the industry's views and actions. The systematic review was performed on the databases Scopus, IEEE Xplore, PubMed, and Google Scholar from 2010 to 2020 and 85 studies were selected. The review concluded that findings remain contradictory especially for the psychosocial domain. Official recommendations from organizations and well-documented researches by academics on child well-being are reassuring if health and safety specifications and particularly the time limit are met. Research is still ongoing, constantly updated and consist of a priority for the scientific community given that technology evolves.

Mesozooplankton grazing minimally impacts phytoplankton abundance during spring in the western North Atlantic.

The impacts of grazing by meso- and microzooplankton on phytoplankton primary production (PP) was investigated in the surface layer of the western North Atlantic during spring. Shipboard experiments were performed on a latitudinal transect at three stations that differed in mixed layer depth, temperature, and mesozooplankton taxonomic composition. The mesozooplankton community was numerically dominated by Calanus finmarchicus at the northern and central station, with Calanus hyperboreus also present at the northern station. The southern station was >10 °C warmer than the other stations and had the most diverse mesozooplankton assemblage, dominated by small copepods including Paracalanus spp. Microzooplankton grazing was detected only at the northern station, where it removed 97% of PP. Estimated clearance rates by C. hyperboreus and C. finmarchicus suggested that at in-situ abundance these mesozooplankton were not likely to have a major impact on phytoplankton abundance, unless locally aggregated. Although mesozooplankton grazing impact on total phytoplankton was minimal, these grazers completely removed the numerically scarce > 10 µm particles, altering the particle-size spectrum. At the southern station, grazing by the whole mesozooplankton assemblage resulted in a removal of 14% of PP, and its effect on net phytoplankton growth rate was similar irrespective of ambient light. In contrast, reduction in light availability had an approximately 3-fold greater impact on net phytoplankton growth rate than mesozooplankton grazing pressure. The low mesozooplankton grazing impact across stations suggests limited mesozooplankton-mediated vertical export of phytoplankton production. The constraints provided here on trophic transfer, as well as quantitative estimates of the relative contribution of light and grazer controls of PP and of grazer-induced shifts in particle size spectra, illuminate food web dynamics and aid in parameterizing modeling-frameworks assessing global elemental fluxes and carbon export.

Grazing effect of flagellates on bacteria in response to phosphate addition in the oligotrophic Cretan Sea, NE Mediterranean.

The planktonic food web in the oligotrophic Mediterranean Sea is dominated by small-sized (<20 µm) microbes, with nanoflagellates being the major bacterial grazers and the main participants in nutrient cycling. Phosphate is a key nutrient in the P-limited Cretan Sea (NE Mediterranean) and P-availability can affect its trophic dynamics. Here, we examined the grazing potential of heterotrophic (HF) and pigmented (PF) nanoflagellates as a response mechanism to phosphate amendment. Flagellate grazing effect on bacteria was quantified in P-amended nutrient-depleted water from the Cretan Sea over the course of 4 days using microcosm experiments. P-addition positively affected HF abundance, while PF abundance remained unchanged. At the community level, P-addition had a negative effect on PF bacterial removal rates. In the control, PF-grazing rate was significantly higher than that of HF throughout the experiment. Pigment analysis showed no changes in phytoplankton community composition as a result of P-addition, indicating that PF grazing rate declined as a physiological response of the cells. The present study emphasizes the dominant grazing role of PF under P-depleted conditions and reveals that during the late stratified season PF respond to P-addition by lowering their grazing rates, enhancing the relative importance of bacterial removal by HF.

Protistan diversity in a permanently stratified meromictic lake (Lake Alatsee, SW Germany).

Protists play a crucial role for ecosystem function(ing) and oxygen is one of the strongest barriers against their local dispersal. However, protistan diversity in freshwater habitats with oxygen gradients received very little attention. We applied high-throughput sequencing of the V9 region (18S rRNA gene) to provide a hitherto unique spatiotemporal analysis of protistan diversity along the oxygen gradient of a freshwater meromictic lake (Lake Alatsee, SW Germany). In the mixolimnion, the communities experienced most seasonal structural changes, with Stramenopiles dominating in autumn and Dinoflagellata in summer. The suboxic interface supported the highest diversity, but only 23 OTUs95% (mainly Euglenozoa, after quality check and removal of operational taxonomic units (OTUs) with less than three sequences) were exclusively associated with this habitat. Eukaryotic communities in the anoxic monimolimnion showed the most stable seasonal pattern, with Chrysophyta and Bicosoecida being the dominant taxa. Our data pinpoint to the ecological role of the interface as a short-term 'meeting point' for protists, contributing to the coupling of the mixolimnion and the monimolimnion. Our analyses of divergent genetic diversity suggest a high degree of previously undescribed OTUs. Future research will have to reveal if this result actually points to a high number of undescribed species in such freshwater habitats.

Real-time evaluation of breast self-examination using computer vision.

Breast cancer is the most common cancer among women worldwide and breast self-examination (BSE) is considered as the most cost-effective approach for early breast cancer detection. The general objective of this paper is to design and develop a computer vision algorithm to evaluate the BSE performance in real-time. The first stage of the algorithm presents a method for detecting and tracking the nipples in frames while a woman performs BSE; the second stage presents a method for localizing the breast region and blocks of pixels related to palpation of the breast, and the third stage focuses on detecting the palpated blocks in the breast region. The palpated blocks are highlighted at the time of BSE performance. In a correct BSE performance, all blocks must be palpated, checked, and highlighted, respectively. If any abnormality, such as masses, is detected, then this must be reported to a doctor to confirm the presence of this abnormality and proceed to perform other confirmatory tests. The experimental results have shown that the BSE evaluation algorithm presented in this paper provides robust performance.

Protistan grazing in a meromictic freshwater lake with anoxic bottom water.

Phagotrophic protists are an important mortality factor of prokaryotes in most aquatic habitats. However, no study has assessed protistan grazing as loss factor of bacterial biomass across the stratification gradient of a temperate freshwater meromictic lake. Protistan grazing effect was quantified in the mixolimnion, the transition zone, and the sulfidic anoxic monimolimnion of Lake Alatsee (Germany). Grazing experiments were performed using prey analogues from the natural prokaryotic assemblage. Daily grazing effect declined from the mixolimnion to the monimolimnion. Heterotrophic flagellates were phagotrophically active in all three water horizons and the main grazers in the monimolimnion. Pigmented flagellates accounted for 70% of total grazing in the mixolimnion and ciliates only for a small fraction of grazing in each depth. Prokaryotic biomass removal peaked in the interface, but protistan impact on the respective prokaryotic abundance was low. Grazing in the anoxic monimolimnion was negligible, with prokaryotic turnover rate being only 0.4% of standing stock. Our results support the assumption that protistan predation in anoxic waters is lower than in oxygenated ones and identify the interface as a microhabitat that supports high grazer biomass, pinpointing the importance of purple sulfur bacteria as carbon source for the upper mixolimnion and the bottom monimolimnion.

Plankton microorganisms coinciding with two consecutive mass fish kills in a newly reconstructed lake.

Lake Karla, Greece, was dried up in 1962 and its refilling started in 2009. We examined the Cyanobacteria and unicellular eukaryotes found during two fish kill incidents, in March and April 2010, in order to detect possible causative agents. Both microscopic and molecular (16S/18S rRNA gene diversity) identification were applied. Potentially toxic Cyanobacteria included representatives of the Planktothrix and Anabaena groups. Known toxic eukaryotes or parasites related to fish kill events were Prymnesium parvum and Pfiesteria cf. piscicida, the latter being reported in an inland lake for the second time. Other potentially harmful microorganisms, for fish and other aquatic life, included representatives of Fungi, Mesomycetozoa, Alveolata, and Heterokontophyta (stramenopiles). In addition, Euglenophyta, Chlorophyta, and diatoms were represented by species indicative of hypertrophic conditions. The pioneers of L. Karla's plankton during the first months of its water refilling process included species that could cause the two observed fish kill events.

Computer vision-based breast self-examination stroke position and palpation pressure level classification using artificial neural networks and wavelet transforms.

This paper focuses on breast self-examination (BSE) stroke position and palpation level classification for the development of a computer vision-based BSE training and guidance system. In this study, image frames are extracted from a BSE video and processed considering the color information, shape, and texture by wavelet transform and first order color moment. The new approach using artificial neural network and wavelet transform can identify BSE stroke positions and palpation levels, i.e. light, medium, and deep, at 97.8 % and 87.5 % accuracy respectively.

Hand motion segmentation against skin colour background in breast awareness applications.

Skin colour modelling and classification play significant roles in face and hand detection, recognition and tracking. A hand is an essential tool used in breast self-examination, which needs to be detected and analysed during the process of breast palpation. However, the background of a woman's moving hand is her breast that has the same or similar colour as the hand. Additionally, colour images recorded by a web camera are strongly affected by the lighting or brightness conditions. Hence, it is a challenging task to segment and track the hand against the breast without utilising any artificial markers, such as coloured nail polish. In this paper, a two-dimensional Gaussian skin colour model is employed in a particular way to identify a breast but not a hand. First, an input image is transformed to YCbCr colour space, which is less sensitive to the lighting conditions and more tolerant of skin tone. The breast, thus detected by the Gaussian skin model, is used as the baseline or framework for the hand motion. Secondly, motion cues are used to segment the hand motion against the detected baseline. Desired segmentation results have been achieved and the robustness of this algorithm is demonstrated in this paper.