3,205 research outputs found
Applying fMRI complexity analyses to the single-subject: a case study for proposed neurodiagnostics
Keeping Up with Technology Through Curriculum Changes in Conjunction with Requirements Imposed on FAA Part 147 Aviation Technologies Schools
Technological evolution is a naturally occurring phenomenon in fields such as aviation technology which deal with a multitude and variation of control systems and the complex devices they operate. Prior to the 1980, the concept of aviation electronics or avionics dealt primarily with communication and navigation systems, most of which were based on radio principles of one form or another. Nowadays, avionics has found its way into virtually every system aboard modern complex aircraft. As traditional steam gauge type instruments are replaced by cathode ray tube and liquid crystal displays, an understanding of these devices has become a necessary addition to many courses in the airframe and powerplant curriculum. While the Federal Aviation Administration (2004) regulates course content in their Part 147 section of the Code of Federal Regulations to a large degree, a substantial portion of this responsibility also rests with the individual aviation technology school. In order to provide students with sufficient knowledge of these advanced systems in addition to the basics, adjustments have to be made to the curriculum from time to time. In the university setting, this responsibility often lays with a curriculum committee working in concert with involved faculty. This combined effort is not always without problems and is especially complicated by the need to satisfy the requirements of both the university and the FAA. The Aviation Technologies Department at Southern Illinois University recently undertook such an effort. In addition to dealing with policies of the university and the FAA, a short timeframe was also placed in the committee necessitating a highly proactive approach to implementing the curricular changes to effect the necessary additions. This article discusses our approach to the process and some conclusions drawn from the experience
Effects of Repetitive End Cleaning on Multimode Plastic Fiber Optic Cable Performance
Periodic cleaning of the end faces of fiber optic cable links in aircraft avionics systems is undertaken as part of routine maintenance or when problems develop. Aeronautical Radio Incorporated (ARINC) has established guidelines for the installation and cleaning of fiber optic cables and components in its standards and a number of isopropyl alcohol based fiber optic cleaning kits are available on the commercial market. While these kits and techniques have proven successful in maintaining signal integrity over the short term, an industry standard as to the effects of repetitive cleaning operations has not been well established. The purpose of this study is to evaluate the effects of repeated end face cleaning on cable transmissivity and make this data available to the industry. It is anticipated the results will provide information useful to the overall determination of cable life cycles enhancing the safety and integrity of fiber optics usage in aircraft avionics systems
Effects of Seismic Lines on the Abundance of Breeding Birds in the Kendall Island Bird Sanctuary, Northwest Territories, Canada
Current plans to increase oil and gas exploration and extraction in the Canadian Arctic include development in the Kendall Island Bird Sanctuary, Northwest Territories. Various studies have shown impacts of seismic lines on vegetation, but the effects on bird abundance in the Arctic are poorly known. We evaluated the impact of new (0.5–1.5 years old) and old (10–35 years old) visible seismic lines within the sanctuary on the abundance of breeding passerines (savannah sparrow, Passerculus sandwichensis; Lapland longspur, Calcarius lapponicus; common redpoll, Carduelis flammea; American tree sparrow, Spizella arborea; and red-necked phalarope, Phalaropus lobatus) in upland tundra, low-centre polygon, and sedge/willow habitats. Along new seismic lines, effects on abundance were not statistically significant for most groups of birds, although the trend in most habitats was for more birds on reference transects than on seismic lines. Significant impacts were found for passerines grouped in upland tundra and for savannah sparrow in sedge/willow. The latter effect (possibly due to standing water along the line) was not significant the following year. Along old seismic lines, abundance of passerines was lower than on reference transects in upland tundra and low-centre polygon habitat, except for Lapland longspurs in upland tundra. Lines created 10–30 years ago have persistent vegetative changes and this appears to have reduced bird abundance. Although we did not plot individual territories, birds were seen crossing the seismic lines and sometimes perched on them, suggesting that they were not avoiding the lines altogether. Instead, these birds may have increased territory size to compensate for vegetative changes along the lines.Les plans actuels visant l’intensification des travaux d’exploration et d’extraction pétrolière et gazière dans l’Arctique canadien visent la mise en valeur du refuge d’oiseaux de l’île Kendall, dans les Territoires du Nord-Ouest. Même si diverses études ont permis de démontrer les effets des profils sismiques sur la végétation, les effets de ces profils sur l’abondance d’oiseaux dans l’Arctique sont méconnus. Au sein du refuge, nous avons évalué l’incidence des nouveaux (de 0,5 à 1,5 an) et anciens (de 10 à 35 ans) profils sismiques visibles sur l’abondance des passériformes nicheurs (bruant des prés, Passerculus sandwichensis; bruant lapon, Calcarius lapponicus; sizerin flammé, Carduelis flammea; bruant hudsonien, Spizella arborea et phalarope à bec large, Phalaropus lobatus) dans la toundra supérieure, le polygone à centre concave et les habitats de laiche et de saule. Le long des nouveaux profils sismiques, les effets enregistrés sur l’abondance n’étaient pas statistiquement importants pour la plupart des groupes d’oiseaux, bien que dans la plupart des habitats, la tendance se traduit par la présence d’un plus grand nombre d’oiseaux dans les transects de référence que dans les profils sismiques. Les effets étaient importants dans le cas des passériformes regroupés dans la toundra supérieure ainsi que dans le cas du bruant des prés évoluant dans l’habitat de laiche et de saule. Ce dernier effet (qui pourrait être attribuable à l’eau stagnante le long du profil) n’était pas considérable l’année suivante. Le long des anciens profils sismiques, les passériformes se trouvaient en moins grande abondance que dans l’habitat du transect de référence de la toundra supérieure et du polygone à centre concave, sauf dans le cas du bruant lapon de la toundra supérieure. Les profils dont l’existence remonte à 10 à 30 ans sont caractérisés par des changements durables du point de vue de la végétation, et cela semble avoir eu pour effet de diminuer l’abondance d’oiseaux. Même si nous n’avons pas tracé de territoires individuels, nous avons aperçu des oiseaux en train de traverser les profils sismiques, où ils se perchaient même parfois, ce qui laisse entrevoir qu’ils n’évitaient pas les profils. Au lieu, il se peut que ces oiseaux disposent d’un territoire plus grand, ce qui compenserait pour les changements végétatifs dénotés le long des profils
Decoupling Graphene from SiC(0001) via Oxidation
When epitaxial graphene layers are formed on SiC(0001), the first carbon
layer (known as the "buffer layer"), while relatively easy to synthesize, does
not have the desirable electrical properties of graphene. The conductivity is
poor due to a disruption of the graphene pi-bands by covalent bonding to the
SiC substrate. Here we show that it is possible to restore the graphene
pi-bands by inserting a thin oxide layer between the buffer layer and SiC
substrate using a low temperature, CMOS-compatible process that does not damage
the graphene layer
Meeting Report: The Use of Newborn Blood Spots in Environmental Research: Opportunities and Challenges
IntroductionDried blood spots (DBS) are routinely collected from newborns in the United States using a heel stick. The DBS are screened for inborn errors of metabolism and other disorders. More states are keeping residual spots and making them available for research purposes. DNA extraction from the DBS has been widely applied; however, the development of methods to measure a range of environmental toxicants in DBS has been a more recent goal for laboratory scientists and epidemiologists.ObjectivesThe purpose of the meeting was to examine the utility of DBS to measure environmental exposures. Speakers and discussants were invited to present data and discuss approaches to measure a range of analytes using DBS.ResultsThis meeting was held on 20 February 2007 at the University of North Carolina at Chapel Hill. The audience consisted of epidemiologists, chemists, and staff from state public health programs, the Centers for Disease Control and Prevention, and the National Institutes of Health. The meeting included presentations on measurement of flame-retarding chemicals and pesticides, metals, perchlorate, infectious agents, markers of immune status, and protein adducts. Analytical methods included mass spectrometry, atomic absorption, molecular methods, and microfluidic techniques. Significant progress was reported, but important challenges remain. Concerns including storage conditions, sample volume, contamination, and normalization require additional systematic evaluation. In addition, DBS storage and access policies require coordination.ConclusionsDBS remain a highly valuable resource for clinical, epidemiologic, and toxicologic investigation. The use of DBS to measure environmental exposures shows promise but additional work is necessary before more widespread use is warranted
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Dynamic multifactor hubs interact transiently with sites of active transcription in Drosophila embryos.
The regulation of transcription requires the coordination of numerous activities on DNA, yet how transcription factors mediate these activities remains poorly understood. Here, we use lattice light-sheet microscopy to integrate single-molecule and high-speed 4D imaging in developing Drosophila embryos to study the nuclear organization and interactions of the key transcription factors Zelda and Bicoid. In contrast to previous studies suggesting stable, cooperative binding, we show that both factors interact with DNA with surprisingly high off-rates. We find that both factors form dynamic subnuclear hubs, and that Bicoid binding is enriched within Zelda hubs. Remarkably, these hubs are both short lived and interact only transiently with sites of active Bicoid-dependent transcription. Based on our observations, we hypothesize that, beyond simply forming bridges between DNA and the transcription machinery, transcription factors can organize other proteins into hubs that transiently drive multiple activities at their gene targets.Editorial noteThis article has been through an editorial process in which the authors decide how to respond to the issues raised during peer review. The Reviewing Editor's assessment is that all the issues have been addressed (see decision letter)
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