921 research outputs found
Cosmological Distance Measurement of 12 Nearby Supernovae IIP with ROTSE-IIIB
We present cosmological analysis of 12 nearby () Type IIP supernovae
(SNe IIP) observed with the ROTSE-IIIb telescope. To achieve precise
photometry, we present a new image differencing technique that is implemented
for the first time on the ROTSE SN photometry pipeline. With this method, we
find up to a 20\% increase in the detection efficiency and significant
reduction in residual RMS scatter of the SN lightcurves when compared to the
previous pipeline performance. We use the published optical spectra and
broadband photometry of well studied SNe IIP to establish temporal models for
ejecta velocity and photospheric temperature evolution for our SNe IIP
population. This study yields measurements that are competitive to other
methods even when the data are limited to a single epoch during the
photospheric phase of SNe IIP. Using the fully reduced ROTSE photometry and
optical spectra, we apply these models to the respective photometric epochs for
each SN in the ROTSE IIP sample. This facilitates the use of the Expanding
Photosphere Method (EPM) to obtain distance estimates to their respective host
galaxies. We then perform cosmological parameter fitting using these EPM
distances from which we measure the Hubble constant to be
, which is consistent with the
standard model values derived using other independent techniques.Comment: 19 pages, 13 figure
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Cretaceous-to-recent record of elevated ³He/⁴He along the Hawaiian-Emperor volcanic chain
Helium isotopes are a robust geochemical tracer of a primordial mantle component in hot spot volcanism. The high ³He/⁴He (up to 35 RA, where RA is the atmospheric ³He/⁴He ratio of 1.39 X 10¯⁶) of some Hawaiian Island volcanism is perhaps the classic example. New results for picrites and basalts from the Hawaiian-Emperor seamount chain indicate that the hot spot has produced high ³He/⁴He lavas for at least the last 76 million years. Picrites erupted at 76 Ma have ³He/⁴He (10-14 RA), which is at the lower end of the range for the Hawaiian Islands but still above the range of modern mid-ocean ridge basalt (MORB; 6-10 RA). This was at a time when hot spot volcanism was occurring on thin lithosphere close to a spreading ridge and producing lava compositions otherwise nearly indistinguishable from MORB. After the hot spot and spreading center diverged during the Late Cretaceous, the hot spot produced lavas with significantly higher ³He/⁴He (up to 24 RA). Although ³He/⁴He ratios stabilized at relatively high values by 65 Ma, other chemical characteristics such as La/Yb and ⁸⁷Sr/⁸⁶Sr did not reach and stabilize at Hawaiian-Island-like values until ~45 Ma. Our limited ³He/⁴He record for the Hawaiian hot spot shows a poor correlation with plume flux estimates (calculated from bathymetry and residual gravity anomalies [Van Ark and Lin, 2004]). If ³He is a proxy for the quantity of primordial mantle material within the plume, then the lack of correlation between ³He/⁴He and calculated plume flux suggests that variation in primordial mantle flux is not the primary factor controlling total plume flux.Keywords: helium, Hawaiian-Emperor chain, MOR
Development of Level 1b Calibration and Validation Readiness, Implementation and Management Plans for GOES-R
A complement of Readiness, Implementation and Management Plans (RIMPs) to facilitate management of post-launch product test activities for the official Geostationary Operational Environmental Satellite (GOES-R) Level 1b (L1b) products have been developed and documented. Separate plans have been created for each of the GOES-R sensors including: the Advanced Baseline Imager (ABI), the Extreme ultraviolet and X-ray Irradiance Sensors (EXIS), Geostationary Lightning Mapper (GLM), GOES-R Magnetometer (MAG), the Space Environment In-Situ Suite (SEISS), and the Solar Ultraviolet Imager (SUVI). The GOES-R program has implemented these RIMPs in order to address the full scope of CalVal activities required for a successful demonstration of GOES-R L1b data product quality throughout the three validation stages: Beta, Provisional and Full Validation. For each product maturity level, the RIMPs include specific performance criteria and required artifacts that provide evidence a given validation stage has been reached, the timing when each stage will be complete, a description of every applicable Post-Launch Product Test (PLPT), roles and responsibilities of personnel, upstream dependencies, and analysis methods and tools to be employed during validation. Instrument level Post-Launch Tests (PLTs) are also referenced and apply primarily to functional check-out of the instruments
Lower limb stiffness and maximal sprint speed in 11-16-year-old boys
The purpose of the study was to examine the relationship between vertical stiffness, leg stiffness and maximal sprint speed in a large cohort of 11-16-year-old boys. Three-hundred and thirty-six boys undertook a 30 m sprint test using a floor-level optical measurement system, positioned in the final 15 m section. Measures of speed, step length, step frequency, contact time and flight time were directly measured whilst force, displacement, vertical stiffness and leg stiffness, were modeled from contact and flight times, from the two fastest consecutive steps for each participant over two trials. All force, displacement and stiffness variables were significantly correlated with maximal sprint speed (p 0.7) relationship with sprint speed, while vertical center of mass displacement, absolute vertical stiffness, relative peak force, and maximal leg spring displacement had large (r > 0.5) relationships. Relative vertical stiffness and relative peak force did not significantly change with advancing age (p > 0.05), but together with maximal leg spring displacement accounted for 96% of the variance in maximal speed. It appears that relative vertical stiffness and relative peak force are important determinants of sprint speed in boys aged 11-16 years, but are qualities that may need to be trained due to no apparent increases from natural development. Practitioners may wish to utilize training modalities such as plyometrics and resistance training to enable adaptation to these qualities due to their importance as predictors of speed in youth
CPT and Lorentz tests with muons
Precision experiments with muons are sensitive to Planck-scale CPT and
Lorentz violation that is undetectable in other tests. Existing data on the
muonium ground-state hyperfine structure and on the muon anomalous magnetic
moment could be analyzed to provide dimensionless figures of merit for CPT and
Lorentz violation at the levels of and .Comment: 4 pages, accepted for publication in Physical Review Letter
Nicoya Peninsula, Costa Rica: A single suite of Caribbean oceanic plateau magmas
The pre‐Tertiary oceanic crust exposed on the west coast of Costa Rica has been broadly referred to as the Nicoya Complex. This study was designed to determine the age of the Nicoya Complex in the Nicoya Peninsula, Playa Jacó, and the Quepos Peninsula using 40Ar‐39Ar radiometric dating and to assess the petrologic relationships between the different localities using major element, trace element, and Sr, Nd, Pb isotopic data. Radiometric ages of basalts and diabases from the Nicoya Peninsula are 88–90 Ma (with a weighted mean of 88.5 Ma), and those of two intrusive rocks (a gabbro and plagiogranite) are both 83–84 Ma. The combined geochemical data indicate that the sampled Nicoya Peninsula rocks belong to a single suite related by fractional crystallization of similar parental magmas. Nd and Pb isotopic ratios indicate a common mantle source distinct from that of mid‐ocean ridge basalts. Both the age and composition of the Nicoya rocks are consistent with the idea that they are a part of the Caribbean Cretaceous oceanic plateau [Donnelly, 1994]. The Jacó lavas are geochemically similar to the Nicoya Peninsula suite, and a single age of 84 Ma is identical to the age of the Nicoya Peninsula intrusives. The one analyzed Quepos basalt has a radiometric age of ∼64 Ma, and it is enriched in incompatible elements relative to the Nicoya rocks. Similarities in Nd and Pb isotopic ratios indicate that the Quepos and Nicoya/Jacó lavas were derived from a similar mantle source to that which produced the Nicoya rocks, possibly the Galapagos plume
Monitoring Alaskan Arctic shelf ecosystems through collaborative observation networks
© The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Danielson, S. L., Grebmeier, J. M., Iken, K., Berchok, C., Britt, L., Dunton, K. H., Eisner, L., V. Farley, E., Fujiwara, A., Hauser, D. D. W., Itoh, M., Kikuchi, T., Kotwicki, S., Kuletz, K. J., Mordy, C. W., Nishino, S., Peralta-Ferriz, C., Pickart, R. S., Stabeno, P. S., Stafford. K. M., Whiting, A. V., & Woodgate, R. Monitoring Alaskan Arctic shelf ecosystems through collaborative observation networks. Oceanography, 35(2), (2022): 52, https://doi.org/10.5670/oceanog.2022.119.Ongoing scientific programs that monitor marine environmental and ecological systems and changes comprise an informal but collaborative, information-rich, and spatially extensive network for the Alaskan Arctic continental shelves. Such programs reflect contributions and priorities of regional, national, and international funding agencies, as well as private donors and communities. These science programs are operated by a variety of local, regional, state, and national agencies, and academic, Tribal, for-profit, and nongovernmental nonprofit entities. Efforts include research ship and autonomous vehicle surveys, year-long mooring deployments, and observations from coastal communities. Inter-program coordination allows cost-effective leveraging of field logistics and collected data into value-added information that fosters new insights unattainable by any single program operating alone. Coordination occurs at many levels, from discussions at marine mammal co-management meetings and interagency meetings to scientific symposia and data workshops. Together, the efforts represented by this collection of loosely linked long-term monitoring programs enable a biologically focused scientific foundation for understanding ecosystem responses to warming water temperatures and declining Arctic sea ice. Here, we introduce a variety of currently active monitoring efforts in the Alaskan Arctic marine realm that exemplify the above attributes.Funding sources include the following: ALTIMA: BOEM M09PG00016, M12PG00021, and M13PG00026; AMBON: NOPP-NA14NOS0120158 and NOPP-NA19NOS0120198; Bering Strait moorings: NSF-OPP-AON-PLR-1758565, NSF-OPP-PLR-1107106; BLE-LTER: NSF-OPP-1656026; CEO: NPRB-L36, ONR N000141712274 and N000142012413; DBO: NSF-AON-1917469 and NOAA-ARP CINAR-22309.07; HFR, AOOS Arctic glider, and Passive Acoustics at CEO and Bering Strait: NA16NOS0120027; WABC: NSF-OPP-1733564. JAMSTEC: partial support by ArCS Project JPMXD1300000000 and ArCS II Project JPMXD1420318865; Seabird surveys: BOEM M17PG00017, M17PG00039, and M10PG00050, and NPRB grants 637, B64, and B67. This publication was partially funded by the Cooperative Institute for Climate, Ocean, & Ecosystem Studies (CICOES) under NOAA Cooperative Agreement NA20OAR4320271, and represents contribution 2021-1163 to CICOES, EcoFOCI-1026, and 5315 to PMEL. This is NPRB publication ArcticIERP-43
Phase 2 Study of the Safety and Tolerability of Maraviroc-Containing Regimens to Prevent HIV Infection in Men Who Have Sex With Men (HPTN 069/ACTG A5305)
Maraviroc (MVC) is a candidate for human immunodeficiency virus (HIV) pre-exposure prophylaxis
Towards a Learning System for University Campuses as Living Labs for Sustainability
Universities, due to their sizeable estates and populations of staff and students, as well as their connections with, and impact within, their local and wider communities, have significant environmental, social and economic impacts. There is a strong movement for universities to become leaders in driving society towards a more sustainable future, through improving the sustainability of the built environment and the universities’ practices and operations, and through their educational, research and wider community engagement missions. Around the globe the concept of ‘Living Labs’ has emerged as an instrument to integrate these different aspects to deliver sustainability improvements, through engaging multiple stakeholders in all of these areas, and through the co-creation of projects to improve the sustainability of the campus environment and operations, and to link these to the education, research, and wider community missions of the institution. This chapter describes a living, shared framework and methodology, the ‘Campus as Living Lab’ learning system, created through global participatory workshops and Living Lab literature, aimed at supporting universities and their Sustainability (Coordinating) Offices in the development and monitoring of Living Lab projects. The framework includes seven categories of supportive data collection and three levels of details to meet different requirements of potential users. The Living Lab framework presented in this chapter, aims to create value and help universities maximise the benefit of Living Lab projects within an institution, support monitoring, reflection and learning from projects, and facilitate communication with stakeholders, and the sharing of practices and learning between peers across the globe. As a living shared, framework and learning system, the framework will adapt and develop over time and within different contexts. To provide feedback and fast (practical) learning from users, the system will be further developed to facilitate transparent peer reviewing
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