Light therapy is applied to older people with dementia as a treatment to reset the biological clock, to improve the cognitive functioning, and to reduce behavioral symptoms. Although the methodological quality of light therapy studies is essential, many aspects concerning the description of the lighting applied are missing. This study reviewed light therapy studies concerning the effects on people with dementia as a way to check the methodological quality of the description of light from a light engineering perspective. Twelve studies meeting the inclusion criteria were chosen for further analysis. Each study was scored on a list of aspects relevant to a proper description of lighting aspects. The overview demonstrates that the overall quality of the methodologies is poor. The studies describe the lighting insufficiently and not in the correct metrics. The robustness of light therapy studies can be improved by involving a light engineer or specialist.
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Learning by creating qualitative representations is a valuable approach to learning. However, modelling is challenging for students, especially in secondary education. Support is needed to make this approach effective. To address this issue, we explore automated support provided to students while they create their qualitative representation. This support is generated form a reference model that functions as a norm. However, the construction of a reference models is still a challenge. In this paper, we present the reference model that we have created to support students in learning about the melatonin regulation in the context of the biological clock.
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De interesse in licht is de afgelopen jaren enorm toegenomen. In het bijzonder betreft dit de invloed van licht op onze gezondheid, prestatie en andere, niet direct visueel gerelateerde aspecten. Het laatste heeft bijvoorbeeld tot gevolg gehad dat basisscholen momenteel op grote schaal uitgerust worden met dynamisch verlichting die de concentratie van scholieren zou verhogen, verlichting in kantoren die de prestatie van medewerkers moet verbeteren en verlichting voor ouderen met dementie die hun verstoorde slaapwaakritme kan stabiliseren. Maar de vraag is nu: hebben we wetenschappelijk bewijs dat deze systemen ook de beoogde claims halen? Dit artikel vraagt aandacht voor de feiten op het gebied van dynamische verlichting voor mensen met dementie en probeert deze van de fictie te onderscheiden.
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Light profoundly impacts many aspects of human physiology and behaviour, including the synchronization of the circadian clock, the production of melatonin, and cognition. These effects of light, termed the non-visual effects of light, have been primarily investigated in laboratory settings, where light intensity, spectrum and timing can be carefully controlled to draw associations with physiological outcomes of interest. Recently, the increasing availability of wearable light loggers has opened the possibility of studying personal light exposure in free-living conditions where people engage in activities of daily living, yielding findings associating aspects of light exposure and health outcomes, supporting the importance of adequate light exposure at appropriate times for human health. However, comprehensive protocols capturing environmental (e.g., geographical location, season, climate, photoperiod) and individual factors (e.g., culture, personal habits, behaviour, commute type, profession) contributing to the measured light exposure are currently lacking. Here, we present a protocol that combines smartphone-based experience sampling (experience sampling implementing Karolinska Sleepiness Scale, KSS ratings) and high-quality light exposure data collection at three body sites (near-corneal plane between the two eyes mounted on spectacle, neck-worn pendant/badge, and wrist-worn watch-like design) to capture daily factors related to individuals’ light exposure. We will implement the protocol in an international multi-centre study to investigate the environmental and socio-cultural factors influencing light exposure patterns in Germany, Ghana, Netherlands, Spain, Sweden, and Turkey (minimum n = 15, target n = 30 per site, minimum n = 90, target n = 180 across all sites). With the resulting dataset, lifestyle and context-specific factors that contribute to healthy light exposure will be identified. This information is essential in designing effective public health interventions.
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A low-cost sensornode is introduced to monitor the 5G EMF exposure in the Netherlands for the four FR1 frequency bands. The sensornode is validated with in-lab measurements both with CW signals as for QAM signals and perform for both cases and for all frequency bands an error less than 1 dB for a dynamic range of 40 dB. This sensor is a follow up of the earlier version of our previously developed sensor and have substantial improvements in terms of linearity, error, and stability.
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Purpose In the Netherlands, the prevalence of visual impairments is the highest among the subgroup of nursing home residents. Over 40 percent are estimated to have visual impairments1. Older adults experience visual problems due to biological aging or eye disease2. These problems can affect several visual functions as well as daily functions in general3,4. Providing appropriate lighting of sufficient intensity and color temperature (CT), and making use of capabilities of the visual environment in the nursing home4 is one of the tasks for professional carers.Light conditions were measured in order to find out to what extent older adults live with the proper lighting conditions. With these data, we wanted to enhance the awareness among care professionals of how light conditions affect the daily lives of the nursing home residents. Moreover, care professionals and technical staff could make the right improvements to the nursing home environment based on the outcomes. Method We assessed light conditions (Konica Minolta chromameter CL-200) in seven nursing homes in the Netherlands. Light conditions were measured in places where residents spend most of their time during the day. In total, 59 living rooms and corridors were assessed in this study. Horizontal and vertical illuminances as well as CT were measured and compared to the values given in a guideline by the Dutch Society for Illumination5. The study was performed between October 2009 and the end of March 2010 at daytime between 10:00 and 15:00 hours. By measuring in autumn, winter and early spring, the contribution of daylight to the indoor illuminance levels was kept at a minimum. Results & Discussion In general lighting conditions encountered in the nursing homes were poor. Four-fifths of the measured illuminances in the common rooms were below the 1,000 lx threshold. Illuminances in the corridors fell below the 200 lx threshold in at least three quarters of the measurements. This means that nursing home residents may have difficulty carrying out tasks and could fall during transfers. The CT of light to which nursing home residents were exposed, fell below the reference value for daylight of 5,000 K with median scores of 3,400 to 4,500 K. High CT of light, in combination with higher illuminances, may positively affect the biological clock, resulting in better sleep quantity and quality.Nursing home staff should be aware of these data in order to arrange better light conditions. Technical staff should be aware that lighting guidelines are not specifically developed for older adults. Special attention should be paid to the fact that older adults need more light than younger persons to perform Activities of Daily Living (ADL).
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Light enables us to see and perceive our environment but it also initiates effects beyond vision, such as alertness. Literature describes that at least six factors are relevant for initiating effects beyond vision. The exact relationship between these factors and alertness is not yet fully understood. In the current field study, personal lighting conditions of 62 Dutch office workers (aged 49.7 ± 11.4 years) were continuously measured and simultaneously self-reported activities and locations during the day were gathered via diaries. Each office worker participated 10 working days in spring 2017. Personal lighting conditions were interpreted based on four of the six factors (light quantity, spectrum, timing, and duration of light exposure). Large individual differences were found for the daily luminous exposures, illuminances, correlated colour temperatures, and irradiances measured with the blue sensor area of the dosimeter. The average illuminance (over all participants and all days) over the course of the day peaked three times. The analysis of the duration of light exposure demonstrated that the participants were on average only exposed to an illuminance above 1000 lx for 72 minutes per day. The interpretation of personal lighting conditions based on the four factors provides essential information since all of these factors may be relevant for initiating effects beyond vision. The findings in the current paper give first in-depth insight in the possibilities to interpret personal lighting conditions of office workers.
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Het project PreciSIAlandbouw heeft precisielandbouwtechnieken ontwikkeld en gevalideerd op vijf thema's: sensortechnologie, kennis en advies, robotisering, digitalisering, en verdienmodellen. Dit rapport bevat de resultaten van robotisering. Er zijn modules ontwikkeld om gewas en onkruid te onderscheiden en locaties van plantdetails nauwkeurig te bepalen.Hogeschool Saxion, lectoraat Lectoraat Smart Mechatronics and Robotics
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Purpose:The International Commission on Illumination (CIE) recommends researchers to investigate a widevariety of behavioural and health outcomes. However, researchers often investigate only a part of occupationalhealth (OH) in relation to light. A literature study (2002–2017) regarding the relationship between office lightingconditions and OH was performed to identify gaps and methodological issues.Method:The OH outcomes investigated in this paper were grouped according to the International Classificationof Diseases and analysed per category: physical and physiological health, mental health, eye health, sleep param-eters and visual comfort.Results:Findings from the literature study (20 eligible papers) showed that all OH aspects were mostly but notexclusively measured subjectively. Furthermore, most studies investigated only a fraction of office lighting par-ameters and OH aspects.Conclusions:It seems that Correlated Colour Temperature (CCT) and illuminance mainly correlate with OH.However, this may also be explained by gaps and methodological issues in studies described in eligible papers.Based on the literature study, an overview was composed elucidating gaps and methodological issues of officelighting and OH studies. It can be used to design and target the purpose of light and health research.
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