420 research outputs found
Alien Registration- Segal, Samuel (Bangor, Penobscot County)
https://digitalmaine.com/alien_docs/10844/thumbnail.jp
A Prototype Virginia Ground Station Network
This paper provides a detailed technical description of a prototype ground station network, the Virginia Ground Station Network (VGSN), developed for the Virginia Cubesat Constellation (VCC) mission. Virginia Tech (VT), University of Virginia (UVA), and Old Dominion University (ODU) have each constructed ground stations to communicate with their respective VCC spacecraft. Initially, each university was responsible for commanding its own spacecraft via its own ground station. As the mission progressed, it was decided to network the ground stations and operations centers together to provide backup communications capability for the overall mission. The NASA Wallops Flight Facility (WFF) UHF smallsat ground station was also included in this network. Implementing the VGSN led to the establishment of successful communications with UVA’s Libertas spacecraft via the VT Ground Station (VTGS), demonstrating the utility of collaboration and of the VGSN. This paper provides a technical overview of the VGSN, details concerning signal processing requirements for the mission, a discussion concerning the radio regulatory process as applied to the VCC mission, and plans for future upgrades of the network to continue to support Virginia (and partner institution) small satellite missions
‘Re-reading Raphael Samuel: Politics, Personality and Performance’
For British historian Raphael Samuel, history and politics were inextricable. Best known as the founder of the history workshop movement, the controversial historian took his stance on the democratisation of history-making, becoming an outspoken advocate for public history. Despite making a significant contribution to contemporary historiography, he remains a neglected, even disparaged, figure. This paper contends that the most significant aspect of Samuel’s historical work was not one or other theory of history or argument about the past but his entire way of being an historian. Samuel embodied as much as expressed his ideas, consciously using his personality as a powerful political tool. It is further argued that conventional approaches to intellectual history, focusing on textual outputs, do not fully recognise the significance of performative modes of thinking. Theoretical approaches to performance as identity offer important insight here but can be too schematic in their view of applied and enacted thought. A biographical approach, by contrast, provides the intimate perspective necessary to fully appreciate the fluidity and complexity of such a personality. The paper first situates Samuel in the context of his earlier life, focusing on how and why he created such a public persona and how he adapted it in response to changing circumstances. It then considers the implications and effectiveness of this persona by assessing how it was perceived and narrated by others, acknowledging, in the process, why different groups engaged with and interpreted it differently
Radical Listening, Action, and Reflection at the Boundaries of Youth Violence Prevention
The purpose of this article is to make visible collaborative pedagogical and research practices that opened space for community members to be co-educators and researchers with students and a professor on a youth violence assessment. We use Third Generation Cultural Historical Activity Theory (CHAT) as a conceptual framework to examine the learning that occurred in the boundary zone of our eight differently situated organizations. As we demonstrate through the inclusion of boundary dialogue excerpts, this process generated more authentic understandings of why racial inequity has persisted in youth violence outcomes. The assessment questions we asked, the key informants we engaged, the data analysis process we undertook, and the substantially different types of findings that emerged were a function of relationship building and radical listening in the boundary zone of our collaboration. We conclude that practices that foster radical listening in boundary work can reframe experiential learning for racial justice
Percutaneous endoscopic gastrostomy in children
PurposePercutaneous endoscopic gastrostomy (PEG) can improve nutritional status and reduce the amount of time needed to feed neurologically impaired children. We evaluated the characteristics, complications, and outcomes of neurologically impaired children treated with PEG.MethodsWe retrospectively reviewed the records of 32 neurologically impaired children who underwent PEG between March 2002 and August 2008 at our medical center. Forty-two PEG procedures comprising 32 PEG insertions and 10 PEG exchanges, were performed. The mean follow-up time was 12.2 (6.6) months.ResultsMean patient age was 9.4 (4.5) years. The main indications for PEG insertion were swallowing difficulty with GI bleeding due to nasogastric tube placement and/or the presence of gastroesophageal reflux disease (GERD). The overall rate of complications was 47%, with early complications evident in 25% of patients and late complications in 22%. The late complications included one gastro-colic fistula, two cases of aggravated GERD, and four instances of wound infection. Among the 15 patients with histological evidence of GERD before PEG, 13 (87%) had less severe GERD, experienced no new aspiration events, and showed increased body weight after PEG treatment.ConclusionPEG is a safe, effective, and relatively simple technique affording long-term enteral nutritional support in neurologically impaired children. Following PEG treatment, the body weight of most patients increased and the levels of vomiting, GI bleeding, and aspiration fell. We suggest that PEG with post-procedural observation be considered for enteral nutritional support of neurologically impaired children
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Human iPS derived progenitors bioengineered into liver organoids using an inverted colloidal crystal poly (ethylene glycol) scaffold.
Generation of human organoids from induced pluripotent stem cells (iPSCs) offers exciting possibilities for developmental biology, disease modelling and cell therapy. Significant advances towards those goals have been hampered by dependence on animal derived matrices (e.g. Matrigel), immortalized cell lines and resultant structures that are difficult to control or scale. To address these challenges, we aimed to develop a fully defined liver organoid platform using inverted colloid crystal (ICC) whose 3-dimensional mechanical properties could be engineered to recapitulate the extracellular niche sensed by hepatic progenitors during human development. iPSC derived hepatic progenitors (IH) formed organoids most optimally in ICC scaffolds constructed with 140 μm diameter pores coated with type I collagen in a two-step process mimicking liver bud formation. The resultant organoids were closer to adult tissue, compared to 2D and 3D controls, with respect to morphology, gene expression, protein secretion, drug metabolism and viral infection and could integrate, vascularise and function following implantation into livers of immune-deficient mice. Preliminary interrogation of the underpinning mechanisms highlighted the importance of TGFβ and hedgehog signalling pathways. The combination of functional relevance with tuneable mechanical properties leads us to propose this bioengineered platform to be ideally suited for a range of future mechanistic and clinical organoid related applications
Ultra-Stable Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (5STAR)
The Spectrometer for Sky-Scanning, Sun-Tracking Atmospheric Research (4STAR) combines airborne sun tracking and sky scanning with diffraction spectroscopy to improve knowledge of atmospheric constituents and their links to airpollution and climate. Direct beam hyperspectral measurement of optical depth improves retrievals of gas constituentsand determination of aerosol properties. Sky scanning enhances retrievals of aerosol type and size distribution.Hyperspectral cloud-transmitted radiance measurements enable the retrieval of cloud properties from below clouds.These measurements tighten the closure between satellite and ground-based measurements. 4STAR incorporates amodular sun-tracking sky-scanning optical head with optical fiber signal transmission to rack mounted spectrometers,permitting miniaturization of the external optical tracking head, and future detector evolution.4STAR has supported a broad range of flight experiments since it was first flown in 2010. This experience provides thebasis for a series of improvements directed toward reducing measurement uncertainty and calibration complexity, andexpanding future measurement capabilities, to be incorporated into a new 5STAR instrument. A 9-channel photodioderadiometer with AERONET-matched bandpass filters will be incorporated to improve calibration stability. A wide dynamic range tracking camera will provide a high precision solar position tracking signal as well as an image of sky conditions around the solar axis. An ultrasonic window cleaning system design will be tested. A UV spectrometer tailored for formaldehyde and SO2 gas retrievals will be added to the spectrometer enclosure. Finally, expansion capability for a 4 channel polarized radiometer to measure the Stokes polarization vector of sky light will be incorporated. This paper presents initial progress on this next-generation 5STAR instrument
Spectral metric spaces for Gibbs measures
We construct spectral metric spaces for Gibbs measures on a one-sided
topologically exact subshift of finite type. That is, for a given Gibbs measure
we construct a spectral triple and show that Connes' corresponding
pseudo-metric is a metric and that its metric topology agrees with the
weak-*-topology on the state space over the set of continuous functions defined
on the subshift. Moreover, we show that each Gibbs measure can be fully
recovered from the noncommutative integration theory and that the
noncommutative volume constant of the associated spectral triple is equal to
the reciprocal of the measure theoretical entropy of the shift invariant Gibbs
measure.Comment: 25 page
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