1,983 research outputs found
Mass production of volume phase holographic gratings for the VIRUS spectrograph array
The Visible Integral-field Replicable Unit Spectrograph (VIRUS) is a baseline
array of 150 copies of a simple, fiber-fed integral field spectrograph that
will be deployed on the Hobby-Eberly Telescope (HET). VIRUS is the first
optical astronomical instrument to be replicated on an industrial scale, and
represents a relatively inexpensive solution for carrying out large-area
spectroscopic surveys, such as the HET Dark Energy Experiment (HETDEX). Each
spectrograph contains a volume phase holographic (VPH) grating with a 138 mm
diameter clear aperture as its dispersing element. The instrument utilizes the
grating in first-order for 350-550 nm. Including witness samples, a suite of
170 VPH gratings has been mass produced for VIRUS. Here, we present the design
of the VIRUS VPH gratings and a discussion of their mass production. We
additionally present the design and functionality of a custom apparatus that
has been used to rapidly test the first-order diffraction efficiency of the
gratings for various discrete wavelengths within the VIRUS spectral range. This
device has been used to perform both in-situ tests to monitor the effects of
adjustments to the production prescription as well as to carry out the final
acceptance tests of the gratings' diffraction efficiency. Finally, we present
the as-built performance results for the entire suite of VPH gratings.Comment: 16 pages, 11 figures, 2 tables. To be published in Proc. SPIE, 2014,
"Advances in Optical and Mechanical Technologies for Telescopes and
Instrumentation", 9151-53. The work presented in this article follows from
arXiv:1207:448
Fluctuation Study of the Specific Heat of MgB2
The specific heat of polycrystalline MgB has been measured with
high resolution ac calorimetry from 5 to 45 K at constant magnetic fields. The
excess specific heat above T is discussed in terms of Gaussian
fluctuations and suggests that MgB is a bulk superconductor with
Ginzburg-Landau coherence length \AA . The transition-width
broadening in field is treated in terms of lowest-Landau-level (LLL)
fluctuations. That analysis requires that \AA . The underestimate
of the coherence length in field, along with deviations from 3D LLL
predictions, suggest that there is an influence from the anisotropy of B
between the c-axis and the a-b plane.Comment: Phys. Rev. B 66, 134515 (2002
Global patterns of diapycnal mixing from measurements of the turbulent dissipation rate
The authors present inferences of diapycnal diffusivity from a compilation of over 5200 microstructure profiles. As microstructure observations are sparse, these are supplemented with indirect measurements of mixing obtained from (i) Thorpe-scale overturns from moored profilers, a finescale parameterization applied to (ii) shipboard observations of upper-ocean shear, (iii) strain as measured by profiling floats, and (iv) shear and strain from full-depth lowered acoustic Doppler current profilers (LADCP) and CTD profiles. Vertical profiles of the turbulent dissipation rate are bottom enhanced over rough topography and abrupt, isolated ridges. The geography of depth-integrated dissipation rate shows spatial variability related to internal wave generation, suggesting one direct energy pathway to turbulence. The global-averaged diapycnal diffusivity below 1000-m depth is O(10?4) m2 s?1 and above 1000-m depth is O(10?5) m2 s?1. The compiled microstructure observations sample a wide range of internal wave power inputs and topographic roughness, providing a dataset with which to estimate a representative global-averaged dissipation rate and diffusivity. However, there is strong regional variability in the ratio between local internal wave generation and local dissipation. In some regions, the depth-integrated dissipation rate is comparable to the estimated power input into the local internal wave field. In a few cases, more internal wave power is dissipated than locally generated, suggesting remote internal wave sources. However, at most locations the total power lost through turbulent dissipation is less than the input into the local internal wave field. This suggests dissipation elsewhere, such as continental margins
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Life-Expectancy Disparities Among Adults With HIV in the United States and Canada: The Impact of a Reduction in Drug- and Alcohol-Related Deaths Using the Lives Saved Simulation Model.
Improvements in life expectancy among people living with human immunodeficiency virus (PLWH) receiving antiretroviral treatment in the United States and Canada might differ among key populations. Given the difference in substance use among key populations and the current opioid epidemic, drug- and alcohol-related deaths might be contributing to the disparities in life expectancy. We sought to estimate life expectancy at age 20 years in key populations (and their comparison groups) in 3 time periods (2004-2007, 2008-2011, and 2012-2015) and the potential increase in expected life expectancy with a simulated 20% reduction in drug- and alcohol-related deaths using the novel Lives Saved Simulation model. Among 92,289 PLWH, life expectancy increased in all key populations and comparison groups from 2004-2007 to 2012-2015. Disparities in survival of approximately a decade persisted among black versus white men who have sex with men and people with (vs. without) a history of injection drug use. A 20% reduction in drug- and alcohol-related mortality would have the greatest life-expectancy benefit for black men who have sex with men, white women, and people with a history of injection drug use. Our findings suggest that preventing drug- and alcohol-related deaths among PLWH could narrow disparities in life expectancy among some key populations, but other causes of death must be addressed to further narrow the disparities
Understanding cooperation through fitness interdependence
Some acts of human cooperation are not easily explained by traditional models of kinship or reciprocity. Fitness interdependence may provide a unifying conceptual framework, in which cooperation arises from the mutual dependence for survival or reproduction, as occurs among mates, risk-pooling partnerships and brothers-in-arms
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Differences between the 2018 and 2019 stratospheric polar vortex split events
Two recent occurrences in February 2018 and January 2019 of a dynamic split in the Northern Hemisphere stratospheric polar vortex are compared in terms of their evolution and predictability. The 2018 split vortex was associated with primarily wavenumberā2 wave forcing that was not well predicted more than 7ā10ādays ahead of time, and was followed by persistent coupling to the surface with strong weather impacts. In 2019 the vortex was first displaced by slow wavenumberā1 amplification into the stratosphere, which was predictable at longer lead times, and then split; the surface impacts following the event were weaker. Here we examine the role of largeāscale climate influences, such as the phase of the El NiƱoāSouthern Oscillation, the Quasiābiennial Oscillation and MaddenāJulian Oscillation, on the wave forcing, surface impacts, and predictability of these two events. Linkages between the forecast error in the stratospheric polar vortex winds with the forecast error in the Quasiābiennial Oscillation and MaddenāJulian Oscillation are examined
A One Health overview, facilitating advances in comparative medicine and translational research.
Table of contentsA1 One health advances and successes in comparative medicine and translational researchCheryl StroudA2 Dendritic cell-targeted gorilla adenoviral vector for cancer vaccination for canine melanomaIgor Dmitriev, Elena Kashentseva, Jeffrey N. Bryan, David T. CurielA3 Viroimmunotherapy for malignant melanoma in the companion dog modelJeffrey N. Bryan, David Curiel, Igor Dmitriev, Elena Kashentseva, Hans Rindt, Carol Reinero, Carolyn J. HenryA4 Of mice and men (and dogs!): development of a commercially licensed xenogeneic DNA vaccine for companion animals with malignant melanomaPhilip J. BergmanA5 Successful immunotherapy with a recombinant HER2-expressing Listeria monocytogenes in dogs with spontaneous osteosarcoma paves the way for advances in pediatric osteosarcomaNicola J. Mason, Josephine S. Gnanandarajah, Julie B. Engiles, Falon Gray, Danielle Laughlin, Anita Gaurnier-Hausser, Anu Wallecha, Margie Huebner, Yvonne PatersonA6 Human clinical development of ADXS-HER2Daniel O'ConnorA7 Leveraging use of data for both human and veterinary benefitLaura S. TremlA8 Biologic replacement of the knee: innovations and early clinical resultsJames P. StannardA9 Mizzou BioJoint Center: a translational success storyJames L. CookA10 University and industry translational partnership: from the lab to commercializationMarc JacobsA11 Beyond docking: an evolutionarily guided OneHealth approach to drug discoveryGerald J. Wyckoff, Lee Likins, Ubadah Sabbagh, Andrew SkaffA12 Challenges and opportunities for data applications in animal health: from precision medicine to precision husbandryAmado S. GuloyA13 A cloud-based programmable platform for healthHarlen D. HaysA14 Comparative oncology: One Health in actionAmy K. LeBlancA15 Companion animal diseases bridge the translational gap for human neurodegenerative diseaseJoan R. Coates, Martin L. Katz, Leslie A. Lyons, Gayle C. Johnson, Gary S. Johnson, Dennis P. O'BrienA16 Duchenne muscular dystrophy gene therapyDongsheng DuanA17 Polycystic kidney disease: cellular mechanisms to emerging therapiesJames P. CalvetA18 The domestic cat as a large animal model for polycystic kidney diseaseLeslie A. Lyons, Barbara GandolfiA19 The support of basic and clinical research by the Polycystic Kidney Disease FoundationDavid A. BaronA20 Using naturally occurring large animal models of human disease to enable clinical translation: treatment of arthritis using autologous stromal vascular fraction in dogsMark L. WeissA21 Regulatory requirements regarding clinical use of human cells, tissues, and tissue-based productsDebra A. WebsterA22 Regenerative medicine approaches to Type 1 diabetes treatmentFrancis N. KaranuA23 The zoobiquity of canine diabetes mellitus, man's best friend is a friend indeed-islet transplantationEdward J. RobbA24 One Medicine: a development model for cellular therapy of diabetesRobert J. Harman
The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brainābehavior relationships after stroke
The goal of the Enhancing Neuroimaging Genetics through MetaāAnalysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using wellāpowered metaā and megaāanalytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and largeāscale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided
Proton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patients [PIRATES]:A Phase I safety and feasibility trial of MRI-guided adaptive particle radiotherapy
Introduction: Radiation dose-escalation for head and neck cancer (HNC) patients aiming to improve cure rates is challenging due to the increased risk of unacceptable treatment-induced toxicities. With āProton Image-guided Radiation Assignment for Therapeutic Escalation via Selection of locally advanced head and neck cancer patientsā (PIRATES), we present a novel treatment approach that is designed to facilitate dose-escalation while minimizing the risk of dose-limiting toxicities for locally advanced HPV-negative HNC patients. The aim of this Phase I trial is to assess the safety & feasibility of PIRATES approach. Methods: The PIRATES protocol employs a multi-faceted dose-escalation approach to minimize the risk of dose-limiting toxicities (DLTs): 1) sparing surrounding normal tissue from extraneous dose with intensity-modulated proton therapy, 2) mid-treatment hybrid hyper-fractionation for radiobiologic normal tissue sparing; 3) Magnetic Resonance Imaging (MRI) guided mid-treatment boost volume adaptation, and 4) iso-effective restricted organ-at-risk dosing to mucosa and bone tissues. The time-to-event Bayesian optimal interval (TITE-BOIN) design is employed to address the challenge of the long DLT window of 6 months and find the maximum tolerated dose. The primary endpoint is unacceptable radiation-induced toxicities (Grade 4, mucositis, dermatitis, or Grade 3 myelopathy, osteoradionecrosis) occurring within 6 months following radiotherapy. The second endpoint is any grade 3 toxicity occurring in 3ā6 months after radiation. Discussion: The PIRATES dose-escalation approach is designed to provide a safe avenue to intensify local treatment for HNC patients for whom therapy with conventional radiation dose levels is likely to fail. PIRATES aims to minimize the radiation damage to the tissue surrounding the tumor volume with the combination of proton therapy and adaptive radiotherapy and within the high dose tumor volume with hybrid hyper-fractionation and not boosting mucosal and bone tissues. Ultimately, if successful, PIRATES has the potential to safety increase local control rates in HNC patients with high loco-regional failure risk. Trial registration: ClinicalTrials.gov ID: NCT04870840; Registration date: May 4, 2021. Netherlands Trial Register ID: NL9603; Registration date: July 15, 2021
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