986 research outputs found
Coupled modelling of subglacial hydrology and calving-front melting at Store Glacier, West Greenland
Abstract. We investigate the subglacial hydrology of Store Glacier in West Greenland,
using the open-source, full-Stokes model Elmer/Ice in a novel 3D application
that includes a distributed water sheet, as well as discrete channelised
drainage, and a 1D model to simulate submarine plumes at the calving front.
At first, we produce a baseline winter scenario with no surface meltwater.
We then investigate the hydrological system during summer, focussing
specifically on 2012 and 2017, which provide examples of high and low
surface-meltwater inputs, respectively. We show that the common assumption
of zero winter freshwater flux is invalid, and we find channels over 1 m2
in area occurring up to 5 km inland in winter. We also find that the production of
water from friction and geothermal heat is sufficiently high to drive
year-round plume activity, with ice-front melting averaging 0.15 m d−1.
When the model is forced with seasonally averaged surface melt from summer,
we show a hydrological system with significant distributed sheet activity
extending 65 and 45 km inland in 2012 and 2017, respectively; while
channels with a cross-sectional area higher than 1 m2 form as far as 55 and 30 km inland. Using daily values for the surface melt as forcing, we
find only a weak relationship between the input of surface meltwater and the
intensity of plume melting at the calving front, whereas there is a strong
correlation between surface-meltwater peaks and basal water pressures. The
former shows that storage of water on multiple timescales within the
subglacial drainage system plays an important role in modulating subglacial
discharge. The latter shows that high melt inputs can drive high basal water
pressures even when the channelised network grows larger. This has
implications for the future velocity and mass loss of Store Glacier, and the
consequent sea-level rise, in a warming world.
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Harvest of the Month Kits for Early Care and Education Settings
Research tells us that a young child’s food preferences develop within the first few years of life as an infant transitions from eating one food to a multitude of foods with varying flavor profiles.1 With the understanding of a young child’s influential years, early care facilities have the ability to target these young years and help influence dietary preferences in a healthy, engaging, and positive way. For my capstone project, four Harvest of the Month (HOTM) Kits will be created to be used in Early Care and Education settings with three-to-five-year-olds. These HOTM Kits will be correlated with Georgia’s Department of Education’s kindergarten through twelfth grade Harvest of the Month resources. Each kit will combine a locally grown Georgia fruit or vegetable, recipe to prepare the seasonal produce, nutritional activity to tie in learning, children’s literature connection, handout to send home, and a local procurement handout. The goal of these kits are to provide a hands-on learning experience to enhance children’s knowledge of fruits and vegetables through activities and literature connections, allow them an opportunity to try new fruits and vegetables through taste testing, and empower them in the kitchen through recipe creations
Mucosal Perfusion Preservation by a Novel Shapeable Tissue Expander for Oral Reconstruction
Background:
There are few methods for expanding oral mucosa, and these often cause complications such as tissue necrosis and expander eruption. This study examines mucosal blood perfusion following insertion of a novel shapeable hydrogel tissue expander (HTE). The canine model used subgingival insertion of HTE following tooth extraction and alveolar bone reduction. The primary goal of this study was to gain understanding of epithelial perfusion and reparative responses of gingival mucosa during HTE expansion.
Methods:
Nine Beagle dogs underwent bilateral premolar maxillary and mandibular tooth extraction. Three to four months later, HTE-contoured inserts were implanted submucosally under the buccal surface of the alveolar ridge. After removal and following a 6- to 7-month period of healing, new HTE implants were inserted at the same sites. The area was assessed weekly for tissue perfusion and volume of expansion. Biopsies for histological analysis were performed at the time of expander removal.
Results:
Within 2 weeks following the second insertion, blood flow returned to baseline (defined as the values of perfusion measurements at the presurgery assessment) and remained normal until hydrogel full expansion and removal. Volume expansion analysis revealed that the hydrogel doubled in volume. Histological assessment showed no macrophage or inflammatory infiltration of the mucosa. No superficial fibrosis, decreased vascularity, or mucosal change was seen.
Conclusion:
Maintenance of adequate tissue perfusion is a clinically important aspect of tissue expander performance to reduce risk of device loss or injury to the patient, particularly for areas with a history of previous surgeries
Perfect state distinguishability and computational speedups with postselected closed timelike curves
Bennett and Schumacher's postselected quantum teleportation is a model of
closed timelike curves (CTCs) that leads to results physically different from
Deutsch's model. We show that even a single qubit passing through a
postselected CTC (P-CTC) is sufficient to do any postselected quantum
measurement, and we discuss an important difference between "Deutschian" CTCs
(D-CTCs) and P-CTCs in which the future existence of a P-CTC might affect the
present outcome of an experiment. Then, based on a suggestion of Bennett and
Smith, we explicitly show how a party assisted by P-CTCs can distinguish a set
of linearly independent quantum states, and we prove that it is not possible
for such a party to distinguish a set of linearly dependent states. The power
of P-CTCs is thus weaker than that of D-CTCs because the Holevo bound still
applies to circuits using them regardless of their ability to conspire in
violating the uncertainty principle. We then discuss how different notions of a
quantum mixture that are indistinguishable in linear quantum mechanics lead to
dramatically differing conclusions in a nonlinear quantum mechanics involving
P-CTCs. Finally, we give explicit circuit constructions that can efficiently
factor integers, efficiently solve any decision problem in the intersection of
NP and coNP, and probabilistically solve any decision problem in NP. These
circuits accomplish these tasks with just one qubit traveling back in time, and
they exploit the ability of postselected closed timelike curves to create
grandfather paradoxes for invalid answers.Comment: 15 pages, 4 figures; Foundations of Physics (2011
Leukocyte and serum S100A8/S100A9 expression reflects disease activity in ANCA-associated vasculitis and glomerulonephritis.
Antineutrophil cytoplasm antibody (ANCA)-associated vasculitis (AAV) commonly results in glomerulonephritis, in which neutrophils and monocytes have important roles. The heterodimer calprotectin (S100A8/S100A9, mrp8/14) is a Toll-like receptor-4 ligand found in neutrophils and monocytes and is elevated in inflammatory conditions. By immunohistochemistry of renal biopsies, patients with focal or crescentic glomerular lesions were found to have the highest expression of calprotectin and those with sclerotic the least. Serum levels of calprotectin as measured by ELISA were elevated in patients with active AAV and the levels decreased but did not normalize during remission, suggesting subclinical inflammation. Calprotectin levels in patients with limited systemic disease increased following treatment withdrawal and were significantly elevated in patients who relapsed compared with those who did not. As assessed by flow cytometry, patients with AAV had higher monocyte and neutrophil cell surface calprotectin expression than healthy controls, but this was not associated with augmented mRNA expression in CD14(+) monocytes or CD16(+) neutrophils. Thus, serum calprotectin is a potential disease biomarker in patients with AAV, and may have a role in disease pathogenesis
Metrology system for measuring mast motions on the NuSTAR mission
A metrology system designed and built for the NuSTAR mission is described. The NuSTAR mission is an orbiting X-ray telescope with a 10 meter focal length. The system consists of two laser pointers mounted rigidly together with a star tracker and the X-ray optics. The focused laser beams illuminates two metrology detectors mounted rigidly with the X-ray detectors. The detectors and optics/lasers are separated by a ∼10 meter deployable (and somewhat flexible) carbon fiber mast. Details about the implementation of the metrology system is discussed in this paper
Canterbury game industry action plan 2022
This report reviews the video game and interactive media industry landscape, and is intended for game studios, local and international investors in the games industry, regional policy makers, central government, local government agencies, Christchurch City Council, and sector stakeholders
Tutorial on Online Partial Evaluation
This paper is a short tutorial introduction to online partial evaluation. We
show how to write a simple online partial evaluator for a simple, pure,
first-order, functional programming language. In particular, we show that the
partial evaluator can be derived as a variation on a compositionally defined
interpreter. We demonstrate the use of the resulting partial evaluator for
program optimization in the context of model-driven development.Comment: In Proceedings DSL 2011, arXiv:1109.032
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Recent Incarceration, Substance Use, Overdose, and Service Use Among People Who Use Drugs in Rural Communities
Importance: Drug use and incarceration have a substantial impact on rural communities, but factors associated with the incarceration of rural people who use drugs (PWUD) have not been thoroughly investigated. Objective: To characterize associations between recent incarceration, overdose, and substance use disorder (SUD) treatment access among rural PWUD. Design, setting, and participants: For this cross-sectional study, the Rural Opioid Initiative research consortium conducted a survey in geographically diverse rural counties with high rates of overdose across 10 US states (Illinois, Wisconsin, North Carolina, Oregon, Kentucky, West Virginia, Ohio, Massachusetts, New Hampshire, and Vermont) between January 25, 2018, and March 17, 2020, asking PWUD about their substance use, substance use treatment, and interactions with the criminal legal system. Participants were recruited through respondent-driven sampling in 8 rural US regions. Respondents who were willing to recruit additional respondents from their personal networks were enrolled at syringe service programs, community support organizations, and through direct community outreach; these so-called seed respondents then recruited others. Of 3044 respondents, 2935 included participants who resided in rural communities and reported past-30-day injection of any drug or use of opioids nonmedically via any route. Data were analyzed from February 8, 2022, to September 15, 2023. Exposure: Recent incarceration was the exposure of interest, defined as a report of incarceration in jail or prison for at least 1 day in the past 6 months. Main outcomes and measures: The associations between PWUD who were recently incarcerated and main outcomes of treatment use and overdose were examined using logistic regression. Results: Of 2935 participants, 1662 (56.6%) were male, 2496 (85.0%) were White; the mean (SD) age was 36 (10) years; and in the past 30 days, 2507 (85.4%) reported opioid use and 1663 (56.7%) reported injecting drugs daily. A total of 1224 participants (41.7%) reported recent incarceration, with a median (IQR) incarceration of 15 (3-60) days in the past 6 months. Recent incarceration was associated with past-6-month overdose (adjusted odds ratio [AOR], 1.38; 95% CI, 1.12-1.70) and recent SUD treatment (AOR, 1.62; 95% CI, 1.36-1.93) but not recent medication for opioid use disorder (MOUD; AOR, 1.03; 95% CI, 0.82-1.28) or currently carrying naloxone (AOR, 1.02; 95% CI, 0.86-1.21). Conclusions and relevance: In this cross-sectional study of PWUD in rural areas, participants commonly experienced recent incarceration, which was not associated with MOUD, an effective and lifesaving treatment. The criminal legal system should implement effective SUD treatment in rural areas, including MOUD and provision of naloxone, to fully align with evidence-based SUD health care policies.</p
Enhancing Perception of Complex Sculptural Forms using Interactive Real-time Ray tracing
This paper looks at experiments into using real-time ray tracing to significantly enhance shape perception of complex three-dimensional digitally created structures. The author is a computational artist whose artistic practice explores the creation of intricate organic three-dimensional forms using simulation of morphogenesis. The generated forms are often extremely detailed, comprising tens of millions of cellular primitives. This often makes depth perception of the resulting structures difficult. His practice has explored various techniques to create presentable artefacts from the data, including high resolution prints, animated videos, stereoscopic installations, 3D printing and virtual reality.
The author uses ray tracing techniques to turn the 3D data created from his morphogenetic simulations into visible artefacts. This is typically a time-consuming process, taking from seconds to minutes to create a single frame. The latest generation of graphics processing units offer dedicated hardware to accelerate ray tracing calculations. This potentially allows the generation of ray traced images, including self-shadowed complex structures and multiple levels of transparency, from new viewpoints at frame rates capable of real-time interaction. The author presents the results of his experiments using this technology with the aim of providing significantly enhanced perception of his generated three-dimensional structures by allowing user-initiated interaction to generate novel views, and utilizing depth cues such as stereopsis, depth from motion and defocus blurring.
The intention is for these techniques to be usable to present new exhibitable works in a gallery context
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