Search

Your search keyword '"Tucker, Scott"' showing total 353 results
Start Over Author "Tucker, Scott"
353 results on '"Tucker, Scott"'

2. Recovering the city street lighting fraction from skyglow measurements in a large-scale municipal dimming experiment

Author

Barentine, John C., Kundracik, František, Kocifaj, Miroslav, Sanders, Jessie C., Esquerdo, Gilbert A., Dalton, Adam M., Foott, Bettymaya, Grauer, Albert, Tucker, Scott, and Kyba, Christopher C. M.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Anthropogenic skyglow dominates views of the natural night sky in most urban settings, and the associated emission of artificial light at night (ALAN) into the environment of cities involves a number of known and suspected negative externalities. One approach to lowering consumption of ALAN in cities is dimming or extinguishing publicly owned outdoor lighting during overnight hours; however, there are few reports in the literature about the efficacy of these programs. Here we report the results of one of the largest municipal lighting dimming experiments to date, involving $\sim$20,000 roadway luminaires owned and operated by the City of Tucson, Arizona, U.S. We analyzed both single-channel and spatially resolved ground-based measurements of broadband night sky radiance obtained during the tests, determining that the zenith sky brightness during the tests decreased by ($-5.4\pm0.9$)% near the city center and ($-3.6\pm0.9$)% at an adjacent suburban location on nights when the output of the street lighting system was dimmed from 90% of its full power draw to 30% after local midnight. Modeling these changes with a radiative transfer code yields results suggesting that street lights account for about ($14\pm1$)% of light emissions resulting in skyglow seen over the city. A separate derivation from first principles implies that street lighting contributes only 2-3% of light seen at the zenith over Tucson. We discuss this inconsistency and suggest routes for future work., Comment: 44 pages, 9 figures; accepted by Journal of Quantitative Spectroscopy and Radiative Transfer

Published
2020
Full Text
View/download PDF

5. Smoke on the water : an historical archaeological assessment of maritime sources of productivity change in the early English tobacco trade

Author

Tucker, Scott Alan, Adams, Jonathan, and Oldfield, John

Subjects
942.06
Abstract

This thesis explores the interaction of numerous factors affecting economic productivity in England’s 17th-century tobacco trade with its Chesapeake colonies, particularly with an eye to transatlantic shipping. This is achieved here through the use of a network inspired analytical framework to provide an assessment of a range of elements surrounding the trade over the course of the 17th century, how these elements interacted, and the degree to which they affected the overall productivity tobacco market. Data used to these means include the extant body of relevant literature, historical documentation, archaeological data, and a case study of an archaeological site near St. Mary’s City, Maryland, USA investigated for the purpose of this thesis. The tobacco economy is examined and analysed based on various inputs, along with various social and political factors. Settlement patterning is studied through geo-spatial archaeological data from Maryland to identify possible causes for the shift in the tobacco collection model from a plantation-front based system to a central warehouse model. Through this, it is argued that the dominant driver for this change was a spread of plantations to more inland sites owing to population growth as the dominant cause. Shipbuilding is scrutinised to identify trends in ship technology and construction methods, showing changes to be both purpose and resource driven. Passenger journals and logbooks are used to examine changes in sailing route throughout the 17th century from England to the Chesapeake, resulting in the identification of a previously unknown route of ocean passage in common usage in the latter half of the 17th century. This change provided generally faster crossings on a less hazardous route, necessitated largely by political and social causes. Making use of these same voyage accounts as a data source, a quantitative study of English merchant ship performance in terms of velocity made good and windward sailing capabilities is provided. Results of this study indicate that advances in ocean crossing times were largely route dependent, with little if any advance in sailing speed over this period. Lastly, the examination of a submerged ballast cluster has provided insights into possible focusses of maritime archaeology in the Chesapeake region. To date, no vessels dating to the early colonial period have been located in the region despite heavy maritime traffic in this era. Ballast discard sites dating to this period are a common yet virtually unexamined site type for this area, and should be afforded additional attention. In sum, this thesis provides a detailed overview of the function of the English-Chesapeake tobacco trade, resulting in a series of network-based models of interaction examining foreign and domestic politics, crew size and mariner wages, tobacco production, the tobacco market, product collection models, sailing routes, hull and sail efficiency, ship construction, time spent at sea, and time spent in port. These are assessed on a temporal scale, allowing for summary of the function of the tobacco economy at various points throughout the 17th century and into the 18th century.

Published
2017

9. Stingray Sensor System for Persistent Survey of the GEO Belt.

Author

Campbell, Tanner, Battle, Adam, Gray, Dan, Chabra, Om, Tucker, Scott, Reddy, Vishnu, and Furfaro, Roberto

Subjects
STINGRAYS, GEOSYNCHRONOUS orbits, PLATING baths, DETECTORS, DATA reduction
Abstract

The Stingray sensor system is a 15-camera optical array dedicated to the nightly astrometric and photometric survey of the geosynchronous Earth orbit (GEO) belt visible above Tucson, Arizona. The primary scientific goal is to characterize GEO and near-GEO satellites based on their observable properties. This system is completely autonomous in both data acquisition and processing, with human oversight reserved for data quality assurance and system maintenance. The 15 ZWO ASI1600MM Pro cameras are mated to Sigma 135 mm f/1.8 lenses and are controlled simultaneously by four separate computers. Each camera is fixed in position and observes a 7.6-by-5.8-degree portion of the GEO belt, for a total of a 114-by-5.8-degree field of regard. The GAIA DR2 star catalog is used for image astrometric plate solution and photometric calibration to GAIA G magnitudes. There are approximately 200 near-GEO satellites on any given night that fall within the Stingray field of regard, and all those with a GAIA G magnitude brighter than approximately 15.5 are measured by the automated data reduction pipeline. Results from an initial one-month survey show an aggregate photometric uncertainty of 0.062 ± 0.008 magnitudes and astrometric accuracy consistent with theoretical sub-pixel centroid limits. Provided in this work is a discussion of the design and function of the system, along with verification of the initial survey results. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

10. Zebrafish raptor mutation inhibits the activity of mTORC1, inducing craniofacial defects due to autophagy-induced neural crest cell death.

Author

Tucker, Scott K., Ghosal, Ritika, Swartz, Mary E., Zhang, Stephanie, and Eberhart, Johann K.

Subjects
*BRACHYDANIO, *NEURAL crest, *CELL death, *BIRDS of prey, *CELL growth, *CELL metabolism, *CARTILAGE regeneration
Abstract

Themechanistic target of rapamycin (mTOR) coordinates metabolism and cell growth with environmental inputs.mTOR forms two functional complexes: mTORC1 and mTORC2. Proper development requires both complexes but mTORC1 has unique roles in numerous cellular processes, including cell growth, survival and autophagy. Here, we investigate the function of mTORC1 in craniofacial development. We created a zebrafish raptor mutant via CRISPR/Cas9, to specifically disrupt mTORC1. The entire craniofacial skeleton and eyes were reduced in size in mutants; however, overall body length and developmental timing were not affected. The craniofacial phenotype associates with decreased chondrocyte size and increased neural crest cell death. We found that autophagy is elevated in raptor mutants. Chemical inhibition of autophagy reduced cell death and improved craniofacial phenotypes in raptor mutants. Genetic inhibition of autophagy, via mutation of the autophagy gene atg7, improved facial phenotypes in atg7;raptor double mutants, relative to raptor single mutants. We conclude that finely regulated levels of autophagy, via mTORC1, are crucial for craniofacial development. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

27. Sylph: life detection probe for a Europa plume

Author

Sherwood, Brent, Lunine, Jonathan, Elliott, John, Imken, Travis, Cable, Morgan, Kempf, Sascha, Southworth, Ben, Tucker, Scott, Waite, J. Hunter, Frick, Andreas, McCoy, Kelli, Karapetian, Arbi, Polit-Casillas, Raul, Kahn, Peter, Oh, David, and Hand, Kevin P

Published
2016

29. Sylph - A SmallSat Probe Concept Engineered to Answer Europa's Big Question

Author

Imken, Travis, Sherwood, Brent, Elliott, John, Frick, Andreas, McCoy, Kelli, Oh, David, Kahn, Peter, Karapetian, Arbi, Polit-Casillas, Raul, Cable, Morgan, Lunine, Jonathan, Kempf, Sascha, Southworth, Ben, Tucker, Scott, and Waite, J. Hunter

Subjects
Spacecraft Instrumentation And Astrionics
Abstract

Europa, the Galilean satellite second from Jupiter, contains a vast, subsurface ocean of liquid water. Recent observations indicate possible plume activity. If such a plume expels ocean water into space as at Enceladus, a spacecraft could directly sample the ocean by analyzing the plume’s water vapor, ice, and grains. Due to Europa’s strong gravity, such sampling would have to be done within 5 km of the surface to sample ice grains larger than 5 µm, expected to be frozen ocean spray and thus to contain non-volatile species critical to a biosignature-detection mission. By contrast, the planned Europa Multiple Flyby Mission’s closest planned flyby altitude is 25 km. Sylph is a concept for a SmallSat free-flyer probe that, deployed from the planned Europa Mission, would directly sample the large grains by executing a single ~2-km altitude plume pass. The 40-kg probe would be deployed by the Europa mission just before it executes a plume fly-through. Within the probe’s 16-hour lifespan, it would autonomously navigate to perform a parallel, simultaneous pass at the lower altitude. The Sylph flight system design concept combines SmallSat technologies with robust traditional components and advanced manufacturing technologies. Its payload would comprise Mini-SUDA (SUrface Dust Mass Analyzer), a dual-channel, miniature impact ionization mass spectrometer. Sylph represents a novel type of SmallSat concept: purpose-built configuration, optimized for the harsh environment at Europa and for planetary-protection requirements, and hybridized from both mainstream and SmallSat components.

Published
2016

38. Shoulder Range of Motion Deficits in Youth Throwers Presenting With Elbow Pain.

Author

Rosen, Michael, Meijer, Karim, Tucker, Scott, Wilcox, C. Luke, Plummer, Hillary A., Andrews, James R., and Ostrander III, Roger V.

Subjects
RANGE of motion of joints, ELBOW, ELBOW injuries, SHOULDER injuries, SHOULDER, ANALYSIS of variance, HANDBALL players, EXPERIMENTAL design, ATHLETES
Abstract

Background: Glenohumeral internal rotation deficit (GIRD) and total arc of motion difference (TAMD) have been associated with elbow injuries in throwing athletes. Hypothesis: Youth pitchers with elbow pain will have greater GIRD and TAMD compared with youth pitchers without elbow pain. Study Design: Cross-sectional study. Level of Evidence: Level 3. Methods: Glenohumeral range of motion of 25 consecutive throwing athletes presenting with elbow pain and that of a matched control group of 18 asymptomatic throwing athletes were compared. Bilateral glenohumeral internal rotation, external rotation, and horizontal adduction at 90° were measured and GIRD and TAMD were then calculated. An analysis of variance was performed to compare range of motion between throwers with and without elbow pain. Results: The average GIRD of the elbow pain group was 32.7° compared with 14.5° in the control group (P < 0.05). The average TAMD in the elbow pain group was 28.3° compared with 6.7° in the control group (P < 0.05). GIRD and TAMD were present in 88% (22 of 25) and 96% (24 of 25) of the elbow pain group versus 33.3% (6 of 18) and 55.6% (10 of 18) of the control group, respectively. Conclusion: Compared with asymptomatic youth pitchers, those presenting with elbow pain have a statistically significant GIRD and TAMD. Clinical Relevance: This study suggests that a GIRD and TAMD may predispose youth pitchers to present with symptomatic elbow pain. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

39. An Innovative Aperture Cover Mechanism Used on SDO/EVE and MMS/SDP

Author

Steg, Stephen, Vermeer, William, Tucker, Scott, and Passe, Heather

Subjects
Mechanical Engineering
Abstract

This paper describes an aperture cover mechanism that was successfully flown in four locations on SDO/EVE, and is awaiting launch in sixteen locations on MMS. This design uses a paraffin actuator and a latch that secures the cover closed and removes the actuator from the load path. This latch allows the assembly to operate both as a light weight contamination cover (SDO/EVE), and also as a high-strength sensor restraint mechanism (MMS/SDP). The paper provides design/analysis/test information about the mechanism.

Published
2014

45. Three-dimensional surgical simulation

Author

Cevidanes, Lucia H.C., Tucker, Scott, Styner, Martin, Kim, Hyungmin, Chapuis, Jonas, Reyes, Mauricio, Proffit, William, Turvey, Timothy, and Jaskolka, Michael

Published
2010

Catalog

Books, media, physical & digital resources
See catalog results