Synthesis of electro-optic modulators for amplitude modulation of light

Electro-optical modulator realizes voltage transfer function in synthesizing birefringent networks. Choice of the voltage transfer function is important, the most satisfactory optimizes the modulator property

Technique developed for measuring transmittance of optical birefringent networks

The transmission characteristics of synthesized optical single-pass and double-pass birefringent networks is obtained by measuring network transmission as a function of network temperature. This technique is most useful for testing those birefringent networks whose bandwidths and periods are very small

Using hypermedia to develop an intelligent tutorial/diagnostic system for the Space Shuttle Main Engine Controller Lab

This is a tutorial/diagnostic system for training personnel in the use of the Space Shuttle Main Engine Controller (SSMEC) Simulation Lab. It also provides a diagnostic capable of isolating lab failures at least to the major lab component. The system was implemented using Hypercard, which is an program of hypermedia running on Apple Macintosh computers. Hypercard proved to be a viable platform for the development and use of sophisticated tutorial systems and moderately capable diagnostic systems. This tutorial/diagnostic system uses the basic Hypercard tools to provide the tutorial. The diagnostic part of the system uses a simple interpreter written in the Hypercard language (Hypertalk) to implement the backward chaining rule based logic commonly found in diagnostic systems using Prolog. Some of the advantages of Hypercard in developing this type of system include sophisticated graphics, animation, sound and voice capabilities, its ability as a hypermedia tool, and its ability to include digitized pictures. The major disadvantage is the slow execution time for evaluation of rules (due to the interpretive processing of the language). Other disadvantages include the limitation on the size of the cards, that color is not supported, that it does not support grey scale graphics, and its lack of selectable fonts for text fields

Birefringent devices Final report, 8 Mar. 1966 - 8 Mar. 1967

Birefringent devices, lossless double-pass network synthesis, and electro-optical amplitude modulator

Fact Sheet: Summer Habitat Use by Adult Female Mule Deer in a Restoration-Treated Ponderosa Pine Forest.

Mule deer (Odocoileus hemionus) populations in the Southwest have experienced declines in the past 50 years due to habitat degradation from fire suppression, exotic species invasion, and increased livestock grazing. Habitat requirements of mule deer include an abundance of high-quality herbaceous forage, vegetation cover that provides protection from predators and weather, and access to reliable water sources. Summer forage availability and quality affects doe productivity and lactation, and fawn survival and growth prior to a resource-limited winter; therefore, high-quality summer habitat is essential for maintaining healthy populations. In northern Arizona, mule deer summer home ranges commonly include ponderosa pine-dominated vegetation types, including extensive areas where large-scale restoration treatments have been implemented or are currently being planned. Restoration treatments that open tree canopies in ponderosa pine and mixed-conifer forests often increase forage abundance and diversity and subsequent use by mule deer; however, these treatments may also reduce hiding cover and alter the microclimate and physical characteristics of day-bed sites. In this study, we sought to examine the effects of forest restoration on the relative intensity of summer habitat-use patterns of mule deer. Our objectives were to 1) spatially define individual home range and core areas, 2) develop a spatially explicit statistical model of intensity of habitat use, and 3) make recommendations that will help land managers provide essential forage and cover attributes for mule deer while restoring forest structure and reducing the risk of uncharacteristic, high-intensity wildfire

Identity, Community, and Nikki S. Lee

This research sheds light on the complex artistry of Korean-born photographer Nikki S. Lee. Although Lee\u27s work initially appears straightforward and casual, this essay explores how photographs in The Hip Hop Project and The Tourist Project actually reinforce and critique specific cultural stereotypes. In performing different ethnic and cultural identities for her photographs, Lee also investigates what it means to one\u27s own identity to be labeled part of a specific community

School-Related Exposure to Nitrogen Dioxide and Asthma Severity in Children Enrolled in the Study of Traffic, Air Quality and Respiratory Health (STAR)

Asthma is an inflammatory disease of the airways characterized by shortness of breath, chest tightness, wheezing and cough. It is one of the most common chronic diseases in children in developed countries, and the prevalence of pediatric asthma has been increasing in recent decades. Both indoor and outdoor air pollution have been identified as risk factors for asthma incidence, prevalence and severity. One of the major gaseous air pollutants, nitrogen dioxide (NO2), is generally related to combustion processes and research has been done to assess its role in asthma outcomes. Unfortunately, studies investigating the relationships between NO2, asthma and respiratory symptoms have remained inconsistent. A major issue that arises in studies of N02 exposure is that most do not account for the high degree of spatial variability that is present in ambient NO2 levels, especially in urban areas. This dissertation research sought to address some of the issues identified in the current literature by: assessing the state of research on traffic-related pollution and asthma in children with a systematic review; employing an exposure assessment method that uses a combination of local measurements and modeling to address the concern of spatial variability in NO2 exposure levels; and using data from a large prospective cohort study of asthmatic children (STAR) to investigate the effects of school-level exposures to N02 on asthma severity. The systematic review it highlights the need for future large sample, prospective cohort studies with longer follow-up periods to investigate further the associations between traffic and asthma in children. Using a combined measurement and modeling approach, this study found a statistically significantly increased risk of worse asthma severity from ambient NO2 exposures at school for children with indoor home N02 exposures above 6 ppb compared to children with low home exposures (OR 1.31 (1.02, 1.69)). These children were more likely to be self-reported minorities with relatively low socioeconomic profiles. There was no association found between asthma severity and length of time spent or mode of transportation used in travel to school for the children in STAR. This study sought to enhance the current literature on school air pollution exposures and pediatric asthma by estimating ambient NO2 levels at schools and investigating the association between school-related N02, including exposures during transport, and asthma severity. Overall results indicated an increased risk of more severe asthma with concurrently high home and school N02 levels, with little effects on asthma severity from exposures during school-related transport

Effect of hexazinone on species distributions and weed competition in lowbush blueberry fields in Maine.

Lowbush blueberries (Vaccinium angustifolium Aiton and V. myrtilloides Michaux) are produced on native or wild stands in Maine and Eastern Canada. The use of the herbicide hexazinone has caused changes in the weed populations in lowbush blueberry fields. To determine the effect of hexazinone on these species and on the growth and productivity of lowbush blueberries in commercial fields in Maine; blueberry and weed population cover, frequency, and blueberry plant stand and yield were sampled on two fields over four years. Cover and frequency of all species were compared to an earlier survey on 14 fields which had been treated once or twice with hexazinone. Blueberry plant stand was compared among the treated fields. Hexazinone-treated fields had a decline in the cover and frequency of a number of weed species and a corresponding increase in blueberry growth and yield. Open ground, bunchberry (Cornus canadensis L.) and dogbane (Apocynum androsaemifolium L.) increased in cover and frequency with hexazinone treatment. Replacement series experiments to assess competitive effects of bunchberry were established on native stands of blueberries in 1986 and 1987. Quadrats were established on prune and crop fields at cover ratios, where c = crop or blueberry and w = weed or bunchberry of 100c/0w, 75c/25w, 50c/50w, 25c/75w, 0c/100w. Dormant blueberry and bunchberry plugs from prune fields were grown in the above proportions in the greenhouse in the summer of 1987. In the field study, relative yields and regression of individual vs associate yield indicates that blueberry and bunchberry growth are equivalent. Blueberry fruit number and yield decreased with increasing bunchberry density. In the greenhouse study, relative yield, regression of individual versus associate yield, and leaf area index of blueberry and bunchberry indicated that blueberry grew as well or better in mixtures than in prune stands. Replacement series experiments indicated that blueberries are competitive with bunchberry but open areas among clones in native fields allow faster growing bunchberry to spread without competition. Two field experiments indicated that imidazoline compounds did not provide selective control of bunchberry but sulfonyl urea compounds merit further research for bunchberry suppression