Dissertations / Theses on the topic 'Light flash'

I fosfeni, o light flash, sono stati percepiti per la prima volta durante il volo verso la luna della navicella Apollo. In genere sono avvertiti al buio, prima di addormentarsi. In questa tesi si studia l'ipotesi di una eccitazione dei fotorecettori della retina da parte di ioni pesanti (carbonio). Campioni di recettori dei bastoncelli vengono irradiati, e viene studiato l'effetto degli ioni carbonio su topo, attraverso la registrazione della risposta elettrofisiologica (segnale retinico e corticale). La tesi si e' sviluppata nell'ambito del progetto ALTEA (Anomaluos Long Term Effect on Astronauts) e tutti gli esperimenti relativi a questo lavoro sono stati svolti a terra. L’obiettivo di ALTEA e’ piu’ generale e riguarda lo studio del rischio funzionale sul sistema nervoso centrale degli astronauti dovuto alla particelle ionizzanti presenti in condizioni di microgravita’ durante le missioni spaziali a lungo termine; ALTEA include sia esperimenti a terra che in orbita, a bordo della Sazione Spaziale Internazionale. La tesi inizia con una introduzione al progetto ALTEA; nel secondo capitolo e’ descritto lo studio chiamato ALTEA-MICE (Mice intermittent Irradiation with Concurrent Electrophysiological monitoring). Nel terzo capitolo sono descritto il sistema costituito dai segmenti esterni dei bastoncelli bovini in sospensione e il meccanismo di attivazione dei fotorecettori. Nel quarto capitolo e quinto capitolo mi sono occupata della interazione radiazione – materia nei tessuti e del caso specifico dell’irradiazione dei campioni dei segmenti esterni contenenti la rodopsina. Nel quinto e ultimo capitolo viene presentato un modello che spiega l’isomerizzazione (attivazione) del retinale della rodopsina come prodotto dell’azione dei radicali liberi provenienti dalla radiolisi dell’acqua.
Phosphenes, or light flashes, have been reported by astronauts since the first Apollo flights to the Moon. They are usually described as occurring in the dark and typically before falling asleep. The light flashes are thought to originate as an effect of high- energy particles interacting with the visual system. The study presented in this thesis investigates the hypothesis of a direct excitation of the rod photoreceptors inside the retina and in particular the interaction between carbon ions and rods. Also the retinal and cortical electrophysiological response of mice submitted to carbon ions irradiation have been studied. This thesis has been developed as a section of the ’Anomalous Long Term Effects on Astronauts’ (ALTEA) program, and all the experiments concerning this thesis took place on ground. The objective of the ALTEA project is more general, and is aimed to assess the functional risks on the central nervous system due to particle flux in microgravity conditions during long term space mission. ALTEA includes a series of experiments both in orbit and on ground. The experiments on board International Space Station will contribute to define the causes of the anomalous phosphene perception of the astronauts by detecting the incident particles through the head of the astronauts and concurrently monitoring the central nervous system functionality. The experiments on ground include the direct irradiation with carbon ions of the outer segments of the rods, and an animal model to investigate the retina/cortex responses of mice irradiated in controlled laboratory experiments. In these experiments on ground I directly contributed in the preparation, the test and the optimization of the experiments and in the following analysis of the data. The whole project has been supported by the Italian Space Agency. The outline of this thesis includes an introduction to the interdisciplinary ALTEA program in the first chapter. In the second chapter ALTEA-MICE (Mice intermittent Irradiation with Concur- rent Electrophysiological monitoring) study is described: the experimental sessions as well as the evidences in the electrophysiological responses of the mouse retina have been described in detail. My role has been chiefly the experimental set up, and I also collaborated on the data analysis. The main results of this investigations have been published. In the third chapter the system of the rod outer segments in suspension and the mechanism of the activation of the photoreceptors are described. The fourth chapter deals with the radiation effects in the biological tissue, and in the fifth chapter there is particular regard to the effects of radiation on samples containing a suspension of rods extracted from bovine retinae. The effects on the rod photoreceptor rhodopsin has been studied: measurements have been performed irradiating with carbon ions the outer segments of the rods in suspension. The amount of the isomeric transformations (bleaching) of the molecules of chromophore into the photoreceptor gives the extent of the effects of radiation. I collaborated to the experiment and carried out the following data analysis. Finally, in the sixth chapter the process of the photo-isomerization of rhodopsin is explained by a model: the process starts with the water radiolysis and the formation of hydroxyl radicals OH in order to achieve the lipid peroxidation, then there is the subsequent emission of visible photons which are responsible for the photoreceptor bleaching. Since rhodopsin is surrounded by phospholipids, present in high concentration in the disc membranes, the effect of chemiluminescence is proposed to be the cause of the photo-transduction cascade and the light flash perception as a consequence. In order to test this hypothesis, a series of experiments was aimed at studying the effects of the hydroxyl radicals produced in an enzymatic way. The main results of this work are illustrated in chapter six, and have been published.

LIGHT INTO THE FLESH / FLESH INTO THE LIGHT explores symbols of evil, sin and redemption in the tv series and the movie Twin Peaks. It is not a critical assessment of David Lynch's body of work. Characters and their actions as well as plots are used as symbols which are then explained based on Genesis, the first book of the Old Testimony. Martin Buber's philosophical insight is also used to shed light on the subject. It is not the aim of this analysis to introduce David Lynch's work from a critical standpoint or from a standpoint of film theory. The aim is to introduce director's key theme, which is one's fight for his soul (essence) whilst facing fear, hesitation, failure but also love, faith and hope.

The biogenic amines serotonin (5HT), dopamine (DA), and octopamine (OA) have been indicated in the regulation of behaviors, including aggression. The flesh fly, Sarcophaga crassipalpis, was used to investigate ontogenetic and circadian changes in amines and aggression. Heads of male flies were analyzed for amine content using high performance liquid chromatography with electrochemical detection (HPLC-ECD) at 3 time points on each of 4 consecutive days in 2 light cycles, 12:12 LD and 15:9 LD. Both DA and OA levels decreased with age. Light-cycle dependent differences were observed for all amines in overall levels and patterns of change throughout the day. A behavioral assay quantified interactive and aggressive behaviors at three time points in the light period for 2 age groups. The daily changes in behavioral profiles differed dependent on age. Correlations from these data can be made between changes in amine levels and time of day, photoperiod, age, and aggressive state.

Pre-harvest sexual maturation in farmed Atlantic salmon, Salmo salar, remains a key biological bottleneck compromising biomass and financial output, production predictability, environmental respect, stock welfare and the overall sustainability of the on-growing industry. The management practices currently in place are not optimized and events of high maturation rate are still sporadically observed. From an ecological perspective, the escape of reproductively competent, domesticated Atlantic salmon constitutes a threat to the integrity of wild stocks. The forecasted expansion of the Scottish salmon industry compels the need for a comprehensive and more reliable control of sexual maturation. The general aim of this research project was to optimize the current management strategy (windows of light-manipulation and quality grading) and test alternative practices (lighting-technologies, selective harvest and triploidization) in the control of pre-harvest sexual maturation within the Atlantic salmon on-growing industry. In that end, a number of trials were performed using stock reared in sea-cages on a full commercial-scale or in tanks on an experimental scale. The results of this project are organized around three experimental chapters dealing consecutively with body-size dimorphism, grading and harvest quality; light manipulations and triploidy. In each chapter, two original manuscripts either published or in review are included. In addition to these experimental results, a literature review chapter composed of two review papers on the photoperiodic synchronization and developmental regulation of maturation in salmonids and on morphological skin colour changes in teleosts (published) are presented. In the first experimental chapters, we aimed at investigating the possibility of detecting and selectively harvesting a high proportion of sexually recruited fish before flesh quality deterioration. Results clearly showed that body-size dimorphisms between maturity cohorts at the end of the anabolic window of reproduction (June/July) are strong and standard predictors of maturation among related populations with the same freshwater history. Dimorphism can therefore be modelled to easily and accurately estimate maturation rate in a number of discrete rearing-units. If required, a high proportion of sexually recruited fish can be selectively harvested as superior quality product while leaving the immature fish for further on-growing. This provides an alternative to visual grilse grading that is not feasible in large-scale aquaculture systems, prevents downgrading and increases production predictability as compared to emergency harvests. Furthermore, our results showed immature males grow faster than immature females which should be further investigated to fully determine gender specific performances and nutritional requirements. Weight-grading performed earlier in the cycle affects the sex-ratio within individual pens and in turn apparent performance. This work also revealed that Atlantic salmon can exhibit significant variations in skin colouration resembling the onset of nuptial display but that are not related to sexual recruitment and do not correlate with reduced flesh quality. This originates from a lack of purine (silver) pigments which was also identified, to a larger extent, as characteristic of the nuptial display. This suggests a degree of desmoltification in these histologically immature fish. The instrumental colouration of the altered phenotype was shown to be improved towards a more silver-like appearance by direct ice-contact. This knowledge could facilitate post-harvest quality grading towards the most appropriate market channel and increase product acceptance and attractiveness. The second experimental chapter investigated the possibility of improving photoperiodic manipulation used to suppress early maturation, currently applied for 6-months during the second winter at sea using wide-spectrum, high-intensity lighting systems. Our results showed that the window of continuous artificial-light (LL) exposure can be reduced to 4-months following its onset in early January without compromising its efficiency in suppressing pre-harvest maturation. In addition, alternative lighting technologies were also highly potent at suppressing sexual maturation. The mean-irradiance (intensity) generated within a commercial sea-cage was inversely proportional to the suppression of nocturnal plasma melatonin (light perception hormone) and negatively correlates with the maturation rate within the commercial sea-pen. Threshold levels of light-intensity required to achieve optimal (total) suppression of sexual maturation are suggested. Alternative, narrow band-width lighting-technologies (cold cathode and light-emitting diodes) present an array of technical, practical, economic and welfare benefits comparing to the system currently in use. Clear improvements of the photoperiod-manipulation strategy were demonstrated and these would reduce economic and environmental costs but also potential impacts on animal welfare. The third experimental chapter showed the strong potential of sterile-triploid Atlantic salmon stocks both in freshwater and seawater. Triploid out-of-season smolts were produced for the first time using a classical accelerated "square-wave" photoperiod. Triploidization affected the smoltification pattern but had no detrimental effects on freshwater and early seawater performances under both a S0+ and S1 regime. This illustrates the need to adapt the timing of seawater transfer for successfully producing triploid Atlantic salmon post-smolts. Following one year of seawater rearing, the prevalence of external deformities was higher in triploids but remained within acceptable levels. Importantly, the incidence of vertebral deformities and ocular cataract was higher in triploids possibly due to their specific requirements. It is suggested that tailoring the diet to the nutritional requirements of triploids holds strong potential for remediation. This must be addressed if the use of sterile-triploid stock is to become a commercial reality. The present research project provides means to optimize the maturation management strategy within the Atlantic salmon on-growing industry through light-manipulation, maturation detection and selective harvest, and quality grading. Proposed improvements have the potential to increase biomass and financial output, production predictability, environmental respect and animal welfare and will allow standardization of the overall control of pre-harvest sexual maturation. Their implementation provides a comprehensive strategy likely to favour a sustainable expansion of the Atlantic salmon industry. From a longer term perspective, the rearing of sterile-triploid stocks is promising and should be actively investigated to isolate domesticated strains from their wild conspecifics. This would also eliminate the need for on-growers to deploy a maturation management strategy that that might still affect stock welfare and remains, despite the strong improvements demonstrated, not 100% reliable, costly, technical and protracted.

碩士
國立交通大學
影像與生醫光電研究所
100
In this thesis, we investigate the illumination system design of flash lens with asymmetric field light source. And we research the distribution of rays and observe the variation of light field by optical software, LightTools and CODE V. Besides, in order to use light power effectively and achieve the design targets, we design two lenses, which are symmetric lens and asymmetric lens. In the end of thesis, we analyze the distinctions, such as illumination, efficiency, tolerance and limitation between two designs.

碩士
國立高雄師範大學
物理學系
107
In this article, based on the meteor's video in 2014, we use the vision program designed by LabVIEW to obtain the light curve of meteor, and analyze the phenomenon of meteor flash. Using the characteristics of flash phenomenon, the source and cause of the origin of meteoroids, a model of flashing phenomenon of meteoroids is proposed. It is known from 108 meteor images data that the flashing phenomenon is concentrated in the Perseids meteor shower (Per) and the Eta Eridanids meteor shower (Eri). The origin of meteoroids of these two meteor showers is comet, and the characteristics of the flashing phenomenon are summarized as The time interval ∆t is about 80-120 ms, and the changing of magnitudes ∆m is between 0.1-0.35. Finally,according to the foregoing characteristics, the methane suddenly combustion model is proposed to explain the phenomenon of meteor flash.

碩士
國立高雄應用科技大學
機械與精密工程研究所
98
As technology advances, there are more and more extensive application of optical elements, of which Fresnel lens is one of the representative products, mainly is the use of micro-structure to change the light path. Compared with the conventional convex lens, lighter is it’s advantage .Most of the present Fresnel lens are for solar concentrator systems, to collect and concentrate light to a small area, increasing the light usage. This study aims to examine the optical characteristics of Fresnel lens, to apply on camera flash light of mobile phones. Today, in order to reduce its power consumption ,mobile flash light switch from the helium flash to LED as substation, but the LED general lighting angle is too wide, so that part of the light falls outside the scope of photography, resulting in limited performance and efficiency. Thus, by characteristics of the Fresnel lens, to adjust the angle of the light irradiation to improve lightening efficiency. The primary object of this study set out with a Fresnel lens ,of which diameter is 5.5mm,By using optical design software TracePro, to design its optical micro-structure, so that large emission angle of LED light source falls within ± 30 ° angle, and to strengthen to 2.4 times in the axis direction. In mold design process, using Moldex3D software to do mold flow analysis helping with mold design ,looking out for best gating design and molding parameters, In the injection molding process, by trial and error method to find shape window, then using Taguchi method to study the influences ,plastic forming parameters of temperature, mold temperature, injection speed and holding pressure process parameters on the forming quality of a Fresnel lens. The experimental results show that holding pressure is the important factor affecting the optical quality ,by the best parameters measured and light distribution curve, the results obtained were compared with analysis of the angle error is less than 2%.

博士
國立交通大學
電子工程系所
94
Abstract In this dissertation, we investigate two novel non-volatile flash memory architectures named PHINES (Programming by hot Hole Injection Nitride Electron Storage) and PREM (Programmable Resistor with Erase-less Memory). We also study a novel Silicon-Nitride Based Light Emitting Transistor (SiNLET). The cell structures, operation principles, and device performances are introduced and discussed. In chapter 2, we construct a novel PHINES memory cell. PHINES uses a nitride trapping storage cell structure. Fowler-Nordheim injection is performed to raise Vt in erase while programming is done by lowering a local Vt through band-to-band tunneling induced hot-hole injection. Two-bits-per-cell feasibility, low power program/erase, good endurance, and good data retention are demonstrated. PHINES cells can be arranged in NOR-type and NAND-type array for both code and data flash applications. In chapter 3, a novel BTB sensing scheme and a modified NAND-type array are introduced. PHINES cell with BTB sensing scheme can eliminate the issue of 2-bit interaction, and a large operation can be obtained in 2-bits-per-cell operation. In chapter 4, the scaling challenges of PHINES cell are discussed. PHINES memory cell shows high scalability, and 15nm generation for 1-bit-per-cell storage and 30nm generation for 2-bit-per-cell storage are feasible in NAND-type array architecture. In chapter 5, a novel non-volatile memory cell named PREM is proposed for SOC applications. PREM combines a novel “erase-less” algorithm and the progressive breakdown of ultra-thin oxide. No extra mask is needed with CMOS standard process. MTP (multi-time programming), MLC (multi-level cell), non-volatility, and low voltage operation are realized. Good reliability is demonstrated. In chapter 6, a novel silicon-nitride based light-emitting transistor (SiNLET) is investigated. This three-terminal electroluminescence device uses a SONOS-type structure, and its process is compatible to standard CMOS devices. Photons are generated by Fowler-Nordheim electron tunnel-injection, band-to-band tunneling induced hot-hole injection, and carrier trapping/recombination via nitride traps. SiNLET with an effective device area of 0.616 �慆2 is demonstrated for display and optical communication purposes.

碩士
國立臺灣師範大學
機電科技研究所
99
In recent years, the technology of Electroencephalography (EEG) is used for the handicapped for tool. Because the EEG equipment is expensive and bulky, the users are not very popular. This research proposes an on-line real-time Brain Computer Interface (BCI) system. We use Electroencephalography (EEG) signal processing methods for directional controls, which may be used for the handicapped for useful tool. This research uses the optical response of the stimulus of the color and frequency of light flashes as feedback to achieve directional acquisition. The electric pole locations include the frontal lobe and occipital lobe of the human brain. The EEG data is processed to filter the unwanted noise, and then the data is processed through Fast-Fourier-Transform (FFT) to observe the difference of the signals of different color and frequency. The FFT data is then analyzed through statistics, Principal Component Analysis (PCA) and Independent Component Analysis (ICA) methods to extract the features. In the end, the data is put into a Supper Vector Machine (SVM) of a machine learning to achieve directional acquisition. This research used 3 test subjects, which the best off-line classification rate could achieve 78.3% correctness, and the mean classification rate could achieve 75.4% correctness. Then, the on-line real time classifier accuracy could achieve 68.33% correctness, which has reached a preliminary practicability.

碩士
國立彰化師範大學
物理學系
99
Flash concept map is used to diagnose and to improve the misconception of light refraction on junior high school students. After answering the choice questions, teacher takes an interview with students before they use Flash concept map to clarify their misconception. The author uses qualitative data, and quantitative data as auxiliary in this study. In the research, the author chooses a junior high school in Changhua County to make the teaching improvement plan. In the beginning, teaching plan and tools are designed for grade 9 students that had learnt light refraction to improve effectiveness. Later, in the formal teaching phase, thirty-two students who haven’t learnt light refraction are chosen to be the objects of study. After pretest and posttest, students carry on Flash concept map examination. To help students to learn better, the research tools include POE teaching design, working sheet and teaching tool. The concept test sheet and Flash concept map are revised by the specialists and team study members, and the credibility of the test sheet is KR-20=.83. The research shows that students learn better in real and virtual image of light and the way of light refract through above teaching tools. When it comes to the misconception, the specialist’s concept map is not totally the same with what students answer. The low achievement students in the hierarchical framework and cross-links of concepts are different from experts. Students tend to believe that the light radiation is a characteristic of light, and they can’t understand that radiation is caused by lens or mirrors.

碩士
國立中央大學
電機工程研究所
95
The present study proposes a new visual evoked potential (VEP)-based brain computer interface (BCI). Users gaze at different spatially separated flash channels (FCs) in order to induce visual evoked signals that have temporal sequences corresponding to the gazed FCs, so that the gazed FC can be recognized and the command mapping to the gazed FC can be sent out to achieve control purposes. To achieve distinct flickering sequences among different FCs, we utilized different frequencies and phases to encode the flashing sequences of different FCs. The proposed system provides the high flexibility in expansion of FC number and high information transfer rate (ITR) which are superior to the traditional SSVEP-based and FVEP-based BCIs. In this thesis, we have built an eight-FC system. The command transfer rate and detected accuracy are 0.52 sec/command and 100%, respectively.

The story of Sarah and Hagar has been treated as one of the foundational stories for the nation of Israel. Yet, Paul, in one deft allegory, will attempt to overturn centuries of theological and historical interpretation. Against other interpretations, I argue that Paul’s untraditional uniting of Hagar, Sinai, and the present Jerusalem together was accomplished through the interpretive key provided in 4:23: the one who comes from a slave has been born because of the flesh, and the one who comes from a free woman has been born through the promise. Paul no longer reads the story of Sarah and Hagar through a lens of separation based on physical realities, but rather through the lens of promise and flesh, as helpfully stated in 4:23. Ishmael was not “cast out” because of his sinfulness or supposed ethnic deficiencies, but rather because he was born “κατὰ σάρκα” and not “δι᾽ ἐπαγγελίας.” These comparative realities are not introduced here in the allegory for the first time; rather, Paul has been building these comparisons as his primary argument since the foundational 2:15-21. This dissertation, therefore, not only interprets the allegory in consideration of the lens of 4:23, but seeks to set the argument within both the thematic and schematic content of Galatians. While the first chapter summarizes and categorizes the typical interpretations of the difficult Galatians 4:21-5:1, the second chapter seeks to critique these approaches to the allegory. The value of applying Paul’s interpretive lens (Gal 4:23) to the allegory is argued for in the third chapter. By using the hermeneutical lens of 4:23, many of the allegory’s difficulties are eased, and the meaning and import of the allegory is clarified. The fourth chapter seeks to set the allegory within the epistle, both thematically and schematically, centering the main propositio around Paul’s remarks to Peter in Galatians 2:15-21. Finally, the last chapter looks at some limited applications of the thesis to OT hermeneutics, specifically in literal and allegorical readings of the Sarah/Hagar incident.