The aim of this study was to test the hypothesis that ryegrass and clover, when grown under optimal conditions in mixed stands, interact in response to available light energy. with other resources non-limiting, pasture yield is determined by the efficiency with which solar radiation is intercepted by canopies and converted into dry matter. The clover-ryegrass interaction under varying light regimes, as experienced in the canopies of these pastures, was studied by investigating the growth and production of ryegrass and clover in relation to light harvesting abilities and photosynthetic utilization of intercepted light. Pasture canopy structure and growth were studied under a four-weekly clipping treatment. The interception of photon flux density (PFD) in the pasture canopy was monitored diurnally and seasonally in mixed and mono cultures. Light use efficiency (C02 fixed/ unit absorbed PFD) as well as photochemical efficiency of photosystem II (Fv/Fm) were studied by monitoring CO2 assimilation rates and chlorophyll fluorescence respectively. The results obtained from this study indicated that interaction did occur between ryegrass and clover, cultivated in mixed pastures. The mixture was capable of more efficient light interception than the mono cultures, which resulted in higher productivity. Light interception abilities, as manifested in canopy architecture, and not physiological utilization of light energy, were found to govern the interaction between the two pasture components. / Thesis (M.Sc.)-University of Natal, Durban, 1993.

"Light, whose beauty within darkness is as jewels that one might cup in one's hands; light that hollowing out darkness and piercing our bodies, blows life into `space"'.'Tadao AndoThis thesis book documents the process and procedure of a two-year study of how daylight can be manipulated by design to enhance and elevate the experiential qualities of sacred space and then applies those characteristics to the design of an architectural thesis project.The exploration involved two major points of focus: one was the exploration to identify the principle qualities and characteristics of natural light and the other, to apply those principles of light into built form.This paper is presented in five processes: an introduction, three types of reflection, and a conclusion. Process I, presents the theoretical underpinning on the subject of light and identifies the key qualities and characteristics of light and the daylighting principles applied by Louis I. Kahn and Tadao Ando in the formulation of sacred space. Process II, presents the articulation of the necessary criteria to design a sacred space. Process III, applies the daylighting strategies to the design of a "one-volume" library for displaying Leonardo da Vinci's Codex. Process IV, presents an alternate scenario and an explanation of architecture as meaning. Process V, summerizes the meaning of the architecture and experience of the Library. 'Ando, Tadao, Complete Works, Phaidon Press Limited, London, (1997). / Department of Architecture

Statement of purpose: The scope of this dissertation was restricted to exemplary studies on the effects of spectrum, intensity and modulation (as described above) of the photic environment of the common reef coral Pocillopora damicornis and its symbiotic dinoflagellate algae. Various aspects of its biology were investigated. In some cases direct comparison was wade with othar species to emphasize similarities or differences. The central hypothesis of this dissertation can be stated as follows: Subtle changes in the spectrum, intensity and modulation of the natural photic environment can produce a profound effect on growth, reproduction, primary production and general metabolism of the reef corals. / Typescript. Thesis (Ph.D.)--University of Hawaii, 1985. Bibliography: leaves 201-221.

Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on May 21, 2009. Major professor: Xiaomin Jin. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "March 2009." Includes bibliographical references (p. 80-84). Also available on microfiche.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 2007. / Title from first page of PDF file (viewed June 11, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 108-123).

No description available.

Light is seldom addressed in archaeological research, despite the fact that, at least in ancient Egypt, it would have impacted upon all aspects of life. When discussing light in Egyptology, the vast majority of scholarly attention is placed on the sun, the primary source of illumination. In comparison, artificial light receives very little attention, primarily due to a lack of archaeological evidence for lighting equipment prior to the 7th century BC. However, 19th and 20th century lychnological studies have exaggerated this point by placing an overwhelming emphasis on decorated lamps from the Greco-Roman Period. In an attempt to move beyond these antiquarian roots, recent scholarship has turned towards examining the role that light, both natural and artificial, played in aspects of ancient societies’ architecture, ideology and religion. The extensive body of archaeological, textual and iconographic evidence that remains from ancient Egypt is well suited to this type of study and forms three core data sets in this thesis. Combining a materials-based examination of artificial light with a contextualized, theoretical analysis contributes to a richer understanding of ancient Egyptian culture from the 3rd to 1st millennium BC. The first three chapters of this study establish a typology of known artificial lighting equipment, as well as a lexicon of lighting terminology. A comparison of the archaeological and textual evidence allows for a discussion on the consumption of lighting in ancient Egypt and its impact on social and economic spheres. From this material it becomes apparent that artificial light was a luxury and this corresponds to its inclusion in religious texts and iconography, as well as the presence of lighting implements in tombs of the wealthy elite. The second half of the thesis examines the ritual application of artificial light, incorporating iconographic and textual evidence, consideration of ritual space and timing, and experimental archaeology. This interdisciplinary approach allows for a discussion of the sensory experience of artificial lighting and its perceived potency in ancient Egypt. It also demonstrates the contribution that Egyptology can make to lychnological and sensory studies of the ancient Near East and Mediterranean by examining the impact of light on phenomenology and aesthetics.

Developing organic light-emitting diodes (OLEDs) as the next generation display devices is not only of industrial interest, but also a scientific challenge in and of itself that requires multi-disciplinary efforts to make the technology successful. Thermally activated delayed fluorescence (TADF) is a recent breakthrough in OLED technology whose prime value is to enable purely organic emitters to recruit the dark triplet excitons in the device, thus avoiding expensive and toxic rare metal based emitters. This thesis is centred on TADF and contains work in three major areas. Firstly, novel ionic TADF emitters were designed for use in light-emitting electrochemical cells (LEECs), which is an alternative electroluminescent device technology to OLEDs, with a much simplified fabrication procedure and architecture. The vast majority of these ionic emitters are based on reported TADF scaffolds where the donors were tethered with an imidazolium hexafluorophosphate group to obtain the ionic character required for LEEC devices (TL and BTL series, Chapter 2). On the other hand, TADF emitters with a carboxylate group were also designed which act as both acceptor and intrinsic charged functionality for LEEC applications (CTL series, Chapter 2). Secondly, attempts were made to create novel TADF molecular scaffolds in order to enrich the current library of TADF emitters. Research efforts were focused on polyaromatic moieties such as anthracene (An series, Chapter 4) and fluoranthene (FA series, Chapter 4) that are seldom reported in TADF literature. In addition, TADF emitters with phosphine oxide as the acceptor group have also been studied (PO series, Chapter 5). Lastly, structure-property relationship studies of TADF emitters were undertaken as a function of tuning of donor and acceptor functionalities using both theoretical and experimental approaches in order to gain more insight for designing desirable TADF emitters (Chapter 3).

Artificial light is an important and necessary part of our urban environment, but has become a threat to biodiversity. It can have substantial direct and indirect effects on populations of all kinds of organisms. While light attraction in bats and moths has been well studied other organisms such as Trichoptera have been largely neglected, despite Trichoptera being one of the most abundant insect orders in freshwater systems. The light attraction of Trichoptera was studied through seasonal data from three different locations in Sweden. The data was examined through meta- and regression analyses to compare catches in light traps and passive traps. The use of relative abundances excluded bias from the species with large populations, and the difference in individuals caught between passive traps and light traps. The results indicated that artificial light could affect Trichoptera populations. Unlike moths, female Trichoptera were more attracted to light than males and attraction to light varied between species. In both cases, size dimorphism could explain the variation. Day-, evening- and night-active species were all attracted to light, but the latter more so. Research has shown that a false flight activity can occur in day-active Trichoptera when a lamp is lit during night, which could explain the capture of day- and evening-active species in a light trap. In all, artificial light could alter Trichoptera populations, changing sex ratios and species composition. This impact should be considered when erecting light sources near waterways.

Plants that develop under foliar shade encounter both low photosynthetically active radiation (PAR) and low red to far red ratios (R:FR). Both of these factors are important in determining developmental responses to shade. Papaya (Carica papaya L.) seedlings grown under filtered shade (low PAR and low R:FR) were compared with seedlings grown under neutral shade (low PAR with R:FR similar to that of full sunlight), and high light (moderate PAR with R:FR similar to that of full sunlight). The results indicated that papaya exhibits a light seeking strategy as evidenced by morphological and anatomical differences between treatments. Based on past research the results also indicate shade developmental responses in papaya to be phytochrome mediated.