Low light level imaging devices have the advantage that they can produce quantitative two dimensional images. The characteristics, structure and operation of different low light level imaging devices are discussed. Cooled slow scanned charged coupled device (CCD) cameras show good detector properties; very low dark noise; low system noise; good spatial resolution; therefore seem ideal for the detection and quantitation of luminogenic assays.

During nutrient-replete growth of microalgae, new photosynthate is allocated toward three different biochemical pools: light harvesting compounds, the biosynthetic apparatus and energy storage. The mechanisms governing allocation of photosynthate between the energy storage compounds carbohydrate and lipid are not well understood. For biofuel production, it is desirable to identify conditions and algal strains that allocate maximum amounts of photosynthate to lipid. This thesis assessed the allocation of photosynthate toward the energy storage pool, and to lipid vs. carbohydrate, at two light levels and during ongoing nitrogen-starvation, for two diatoms and two chlorophytes. Nitrogen-starvation resulted in an increase in the photosynthate allocated toward energy storage, however the magnitude of change was determined by a combination of species and light level. Of the four species studied, the diatom Chaetoceros muelleri, grown in high light, accumulated lipid during N-starvation at a relatively high rate, making it a good candidate for biofuel production.

This thesis investigates the relationship between light, visibility and women’s perceived safety through a case study. Specifically, it investigates visibility related to light levels and light distribution at four bus stops in urban areas of Stockholm, Sweden. The methodology is divided into Literature review and Case study. The first provides an overview on theories related to visibility, light and perceived safety in the urban environment.  Then, the Case study presents an investigation through Qualitative and Quantitative research. The Qualitative research is divided into three steps: (1) firstly, four bus stops are selected in urban areas through the Light Zones concept tool [12] and analyzed by the author through the V/P Theory [11]; (2) then, the relationship between light, visibility and women’s safety perception is evaluated through an online form; (3) and finally, this relationship is further investigated during on-site interviews in order to explore how light distribution affect women’s perception. During the Quantitative research, Luminance and Illuminance measurements are developed in order to assess light levels and light distribution at the area of the four bus stops. From the results of all methodology steps, the relationship between light, visibility and women’s perceived safety was discussed and three main factors were assessed to be important to women’s perceived safety at bus stop areas. The first factor is connected to light distribution, and this thesis understood that women’s perceived safety is connected to light on their immediate surroundings, rather than on further distances. The second factor is connected to light levels, and it was concluded that higher light levels on immediate surroundings increase visibility thus, increasing safety perception. The third factor is connected to the experienced light, in which this thesis recognized that previous experiences and contexts related to light influence how women perceive safety in urban spaces.

Movements of long-distance migratory birds are frequently well timed and routed in order to maximise individual fitness. However, individual timing of events or environmental conditions experienced have a potential to carry over into subsequent annual cycle stages and may have delayed fitness consequences. Therefore, knowledge of these seasonal interactions is crucial to identify key periods and regions that limit survival beyond the breeding period and thus to fully understand population dynamics of migratory species. Despite current evidence for seasonal interactions, there is no detailed knowledge of the complex of relationships within the full annual cycle, differences between sexes and populations or impact of environmental conditions during moult in one species. To unveil this system of seasonal interactions within the annual cycle, we directly tracked 103 great reed warblers (Acrocephalus arundinaceus) using light-level geolocators from five breeding sites across the breeding range to obtain information on timing and positions of annual cycle events. We then combined this information with various remotely sensed habitat condition metrics and stable isotopic composition of feathers from the non-breeding grounds to identify and quantify carry-over effects within the full annual cycle. Our...

<p>The purpose of this study is to survey and evaluate if the individual contrast sensitivity and preferences for horizontal and vertical lighting level correspond to the values that standard SS-EN 12464-1 recommends for the workplace- and surrounding light levels.</p><p>This study examines if lighting should be adapted after the individuals’ need or if a general value can be found that will cover every individuals’ need for a workplace and surrounding light level. This study also examines if parameters like sex, age and/or glasses/lenses have an effect on the amount of lighting that the test subjects need. Lastly we compared the values concerning the relationship between workplace- and surrounding light levels with standard SS-EN 12464-1’s recommendations.</p><p>The study is carried out with an experimental design that surveys 220 test subjects who were chosen by a selection of convenience. The test subjects did perform a test where they estimated their individual need for lighting in office environments regarding lighting for workplace and its surroundings. Every test subject carried out the test where they repeated the same attempt three times, to establish if the individual lighting need oscillated or if it was constant, whereupon the results were analyzed, compiled and compared to standard SS-EN 12464-1.</p><p>The results show that the minim- and maxim value for the test subjects is between 70 – 4300 lux. The result varies with different parameters such as sex, age and glasses/lenses. We could also state that the relationship between workplace- and surrounding light levels is slightly higher than what standard SS-EN 12464-1 recommends, which should be taken into consideration when planning future lighting constructions.</p><p>Based on the results in this study, our conclusion is that standard SS-EN 12464-1 does not cover the needs on the comfort levels that the test subjects indicated. The values that the test subjects indicated differ from the values that standard SS-EN 12464-1 recommends.</p><p>Since there is a huge spread of the experienced need for lighting between individuals and age groups, we draw the conclusion that general values of measure can’t be applied as a standard on neither workplace- nor surrounding light levels. To fulfill the needs that users have, the lighting construction should be adapted for the individual and give a lighting flood that will fill the individual needs for workplace lighting.</p>

The purpose of this study is to survey and evaluate if the individual contrast sensitivity and preferences for horizontal and vertical lighting level correspond to the values that standard SS-EN 12464-1 recommends for the workplace- and surrounding light levels. This study examines if lighting should be adapted after the individuals’ need or if a general value can be found that will cover every individuals’ need for a workplace and surrounding light level. This study also examines if parameters like sex, age and/or glasses/lenses have an effect on the amount of lighting that the test subjects need. Lastly we compared the values concerning the relationship between workplace- and surrounding light levels with standard SS-EN 12464-1’s recommendations. The study is carried out with an experimental design that surveys 220 test subjects who were chosen by a selection of convenience. The test subjects did perform a test where they estimated their individual need for lighting in office environments regarding lighting for workplace and its surroundings. Every test subject carried out the test where they repeated the same attempt three times, to establish if the individual lighting need oscillated or if it was constant, whereupon the results were analyzed, compiled and compared to standard SS-EN 12464-1. The results show that the minim- and maxim value for the test subjects is between 70 – 4300 lux. The result varies with different parameters such as sex, age and glasses/lenses. We could also state that the relationship between workplace- and surrounding light levels is slightly higher than what standard SS-EN 12464-1 recommends, which should be taken into consideration when planning future lighting constructions. Based on the results in this study, our conclusion is that standard SS-EN 12464-1 does not cover the needs on the comfort levels that the test subjects indicated. The values that the test subjects indicated differ from the values that standard SS-EN 12464-1 recommends. Since there is a huge spread of the experienced need for lighting between individuals and age groups, we draw the conclusion that general values of measure can’t be applied as a standard on neither workplace- nor surrounding light levels. To fulfill the needs that users have, the lighting construction should be adapted for the individual and give a lighting flood that will fill the individual needs for workplace lighting.

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The high electricity prices are a talked about issue in today's society where many peoplefind themselves in a critical situation as a result of them. In a more long-termperspective, Sweden faces a goal of a comprehensive transformation of the energysystem. Lighting is a contributing factor to the energy system and energy use. Light inthe form of lighting is important for the visibility of objects and the surroundings, whichis a contributing factor to safety in society.The stock market price for electricity prices in December 2022 shows a sharp risethroughout Sweden and the forecast for today's electricity prices continues to rise(Konsumenternas, 2022). Energy consumption has a direct correlation to electricitycosts and dimmed LED light sources lead to lower energy consumption (Jägerbrand,2011). An important aspect in how the sense of safety, security and architecture isemphasized is the color rendering and light level of the lighting. A study carried out byMinchen et al (2020) proves that a light source with an increased color saturation and alower used illuminance can give rise to an equivalent visibility of a board as a lightsource with lower color saturation and higher illuminance.The aim is to identify and describe previous areas of knowledge about the colorsaturation and color reproduction of light sources. Tentative theory must be tested tosee if future outcomes can be predicted with the aim of lowering the light level andenergy consumption through increased color saturation and its impact on visibility andperceived safety.In order to achieve the aim and answer the study's questions, a literature search has beencarried out, in both primary and secondary sources, with keywords and search stringsin the scientific database Web of science together with the help of the snowball methodand snowball technique. In addition, available light source data from light sourcesuppliers has been analyzed to investigate the correlation between energy consumptionand color saturation. In order to further investigate the subject and answer the questions,an experiment was carried out with two different lighting scenarios of a modeled tunnel.During the experiment, participants contributed quantitative and qualitative data byanswering questionnaires for these scenarios.The study shows that light color saturation has an impact on the energy efficiency oflight sources and that different interpretations of how light color saturation and lightlevel affect the perceived visibility. The study indicates that a lower light level can beapplied without negatively affecting safety if other factors for the environment are takeninto account, where one of the contributing factors may be light color saturation. / De höga elpriserna är en omtalad fråga i dagens samhälle där många befinner sig i enkritisk situation till följd av dem. I ett mer långsiktigt perspektiv står Sverige inför ettmål till en omfattande omställning av energisystemet. Belysning är en bidragande faktortill energisystemet och energianvändningen. Ljus i form av belysning är viktig försynbarheten till objekt och omgivningen som är en bidragande faktor till tryggheten isamhället.Börspriset för elpriser i december 2022 visar en kraftig stigning i hela Sverige ochprognosen för dagens elpriser fortsätter att stiga (Konsumenternas, 2022).Energiförbrukningen har en direkt korrelation till elkostnaderna och dimrade LEDljuskällorleder till lägre energiförbrukning (Jägerbrand, 2011). En viktig aspekt i hurkänslan av trygghet, säkerhet och arkitektur framhävs är belysningens färgåtergivningoch ljusnivå. En studie utförd av Minchen et al (2020) påvisar till att en ljuskälla meden ökad färgmättnad och en lägre använd belysningsstyrka kan ge upphov till enlikvärdig synbarhet av en tavla som en ljuskälla med lägre färgmättnad och högrebelysningsstyrka.Syftet är att identifiera och beskriva tidigare kunskapsområden om ljuskällorsfärgmättnad och färgåtergivning. Tentativ teori ska prövas till om framtida utfall kanförutsägas i syfte att sänka ljusnivån och energiförbrukningen genom en ökadfärgmättnad och dess påverkan på synbarheten och den upplevda tryggheten.För att uppnå syftet och besvara studiens frågeställningar har en litteratursökninggenomförts, i både primära och sekundära källor, med nyckelord och söksträngarvetenskapliga databasen Web of science tillsammans med hjälp av snöbollsmetodenoch snöbollsteknik. Därtill har tillgänglig ljuskälledata från ljuskälleleverantöreranalyserats för att undersöka korrelation mellan energiförbrukning och färgmättnad.För att vidare undersöka ämnet och besvara frågeställningarna genomfördes ettexperiment med två olika belysnings-scenarion av en modellerad tunnel. Underexperimentet bidrog deltagarna med kvantitativa och kvalitativa data genom att besvaraenkäter till dessa scenarion.Studien visar att ljusfärgmättnaden har en påverkan på ljuskällors energieffektivitet ochatt olika tolkningar hur ljusfärgmättnad och ljusnivå påverkar den upplevdasynbarheten. Studien indikerar att en lägre ljusnivå kan appliceras utan att påverkatryggheten negativt om andra faktorer för omgivningen tas i beaktning, där en av dombidragande faktorerna kan vara ljusfärgmättnad.