4,586 research outputs found
ROWS wave spectral data collected in SAXON-FPN, November 1990
High-resolution directional wave spectra obtained with the NASA Ku-band radar ocean wave spectrometer (ROWS) on the Naval Research Laboratory P-3 aircraft during SAXON-FPN (SAR and X-Band Ocean Nonlinearities Experiment-Forschungsplattform Nordsee) experiments in the North Sea in November 1990 are presented. This experiment was the first in which the ROWS was operated with its new pc-based high-speed digital data acquisition system
Large Electric Dipole Moments of Heavy Leptons
In many models of CP violation, the electric dipole moments (EDMs) of leptons
scale as the cube of the lepton mass. In these models, the EDM of a 100 GeV
heavy lepton would be a billion times greater than that of the muon, and could
be as large as a 0.01 e-fermi. In other models, in which the heavy leptons have
different properties from the lighter generations, a similarly large EDM can be
obtained. A large EDM could dominate the electromagnetic properties of heavy
leptons. The angular distribution and production cross-section of both charged
and neutral heavy leptons with large dipole moments is calculated and
discussed. The interesting possibility that a heavy neutrino with a large EDM
could leave an ionization track in a drift chamber is investigated.Comment: Discussion expanded extensively to include model-dependence of
results. Calculations unchanged. Note Added To Acknowledgments: This paper is
dedicated to the memory of Nathan Isgu
Gradient Boosted Machine Learning Model to Predict H2, CH4, and CO2 Uptake in Metal–Organic Frameworks Using Experimental Data
Predictive screening of metal–organic framework (MOF) materials for their gas uptake properties has been previously limited by using data from a range of simulated sources, meaning the final predictions are dependent on the performance of these original models. In this work, experimental gas uptake data has been used to create a Gradient Boosted Tree model for the prediction of H2, CH4, and CO2 uptake over a range of temperatures and pressures in MOF materials. The descriptors used in this database were obtained from the literature, with no computational modeling needed. This model was repeated 10 times, showing an average R2 of 0.86 and a mean absolute error (MAE) of ±2.88 wt % across the runs. This model will provide gas uptake predictions for a range of gases, temperatures, and pressures as a one-stop solution, with the data provided being based on previous experimental observations in the literature, rather than simulations, which may differ from their real-world results. The objective of this work is to create a machine learning model for the inference of gas uptake in MOFs. The basis of model development is experimental as opposed to simulated data to realize its applications by practitioners. The real-world nature of this research materializes in a focus on the application of algorithms as opposed to the detailed assessment of the algorithms
Optogenetic Multiphysical Fields Coupling Model for Implantable Neuroprosthetic Probes
AuthorsOptogenetic-based neuroprosthetic therapies are increasingly being considered for human trials. However, the optoelectronic design of clinical-grade optogenetic-based neuroprosthetic probes still requires some thought. Design constraints include light penetration into the brain, stimulation efficacy, and probe/tissue heating. Optimisation can be achieved through experimental iteration. However, this is costly, time-consuming and ethically problematic. Hence it is highly desirable to have an alternative to excessive animal trials. Thus, a simulation tool for optimising probe design can be an important benefit for the community. The challenge is to understand the interplay between the optical, neural and thermal aspects in the interaction of probe and living neural tissue. In this work, we propose a model which combines these aspects to allow clinically orientated neuroprosthetic teams to design neuroprosthetic probes for optogenetic therapies. Our model provides analyses for optical, thermal and optogenetic electrophysiological processes based on the energy equivalence and exchange among different physical fields. To validate and calibrate the model, optogenetic implantable neuroprosthetic arrayed probes based on miniature LEDs were developed. Then, optical, thermal measurement and neural photocurrent recording experiments were implemented on the probes. We can then provide analysis on exemplar arrayed neural probes
A peroxisome proliferator-activated receptor-δ agonist provides neuroprotection in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine model of Parkinson's disease
Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.Peer reviewedPublisher PD
Rope trauma, sedation, disentanglement, and monitoring-tag associated lesions in a terminally entangled North Atlantic right whale (Eubalaena glacialis)
Author Posting. © Society for Marine Mammalogy, 2012. Re-use of this article is permitted in accordance with the Terms and Conditions set out at http://wileyonlinelibrary.com/onlineopen#OnlineOpen_Terms. The definitive version was published in Marine Mammal Science 29 (2013): E98–E113, doi:10.1111/j.1748-7692.2012.00591.x.A chronically entangled North Atlantic right whale, with consequent emaciation was sedated, disentangled to the extent possible, administered antibiotics, and satellite tag tracked for six subsequent days. It was found dead 11 d after the tag ceased transmission. Chronic constrictive deep rope lacerations and emaciation were found to be the proximate cause of death, which may have ultimately involved shark predation. A broadhead cutter and a spring-loaded knife used for disentanglement were found to induce moderate wounds to the skin and blubber. The telemetry tag, with two barbed shafts partially penetrating the blubber was shed, leaving barbs embedded with localized histological reaction. One of four darts administered shed the barrel, but the needle was found postmortem in the whale with an 80º bend at the blubber-muscle interface. This bend occurred due to epaxial muscle movement relative to the overlying blubber, with resultant necrosis and cavitation of underlying muscle. This suggests that rigid, implanted devices that span the cetacean blubber muscle interface, where the muscle moves relative to the blubber, could have secondary health impacts. Thus we encourage efforts to develop new tag telemetry systems that do not penetrate the subdermal sheath, but still remain attached for many months.Funding from NOAA Cooperative Agreement NA09OAR4320129, PO
EA133F09SE4792, M. S. Worthington Foundation, North Pond Foundation, Sloan and
Hardwick Simmons, and Woods Hole Oceanographic Institution Marine Mammal
Center
The Red Sea, Coastal Landscapes, and Hominin Dispersals
This chapter provides a critical assessment of environment, landscape and resources in the Red Sea region over the past five million years in relation to archaeological evidence of hominin settlement, and of current hypotheses about the role of the region as a pathway or obstacle to population dispersals between Africa and Asia and the possible significance of coastal colonization. The discussion assesses the impact of factors such as topography and the distribution of resources on land and on the seacoast, taking account of geographical variation and changes in geology, sea levels and palaeoclimate. The merits of northern and southern routes of movement at either end of the Red Sea are compared. All the evidence indicates that there has been no land connection at the southern end since the beginning of the Pliocene period, but that short sea crossings would have been possible at lowest sea-level stands with little or no technical aids. More important than the possibilities of crossing the southern channel is the nature of the resources available in the adjacent coastal zones. There were many climatic episodes wetter than today, and during these periods water draining from the Arabian escarpment provided productive conditions for large mammals and human populations in coastal regions and eastwards into the desert. During drier episodes the coastal region would have provided important refugia both in upland areas and on the emerged shelves exposed by lowered sea level, especially in the southern sector and on both sides of the Red Sea. Marine resources may have offered an added advantage in coastal areas, but evidence for their exploitation is very limited, and their role has been over-exaggerated in hypotheses of coastal colonization
The HERMES Dual-Radiator Ring Imaging Cerenkov Detector
The construction and use of a dual radiator Ring Imaging Cerenkov(RICH)
detector is described. This instrument was developed for the HERMES experiment
at DESY which emphasizes measurements of semi-inclusive deep-inelastic
scattering. It provides particle identification for pions, kaons, and protons
in the momentum range from 2 to 15 GeV, which is essential to these studies.
The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall
of silica aerogel tiles. The use of aerogel in a RICH detector has only
recently become possible with the development of clear, large homogeneous and
hydrophobic aerogel. A lightweight mirror was constructed using a newly
perfected technique to make resin-coated carbon-fiber surfaces of optical
quality. The photon detector consists of 1934 photomultiplier tubes for each
detector half, held in a soft steel matrix to provide shielding against the
residual field of the main spectrometer magnet.Comment: 25 pages, 23 figure
Changes in microphytobenthos fluorescence over a tidal cycle: implications for sampling designs
Intertidal microphytobenthos (MPB) are important primary producers and provide food for herbivores in soft sediments and on rocky shores. Methods of measuring MPB biomass that do not depend on the time of collection relative to the time of day or tidal conditions are important in any studies that need to compare temporal or spatial variation, effects of abiotic factors or activity of grazers. Pulse amplitude modulated (PAM) fluorometry is often used to estimate biomass of MPB because it is a rapid, non-destructive method, but it is not known how measures of fluorescence are altered by changing conditions during a period of low tide. We investigated this experimentally using in situ changes in minimal fluorescence (F) on a rocky shore and on an estuarine mudflat around Sydney (Australia), during low tides. On rocky shores, the time when samples are taken during low tide had little direct influence on measures of fluorescence as long as the substratum is dry. Wetness from wave-splash, seepage from rock pools, run-off, rainfall, etc., had large consequences for any comparisons. On soft sediments, fluorescence was decreased if the sediment dried out, as happens during low-spring tides on particularly hot and dry days. Surface water affected the response of PAM and therefore measurements used to estimate MPB, emphasising the need for care to ensure that representative sampling is done during low tide
A Study of the Quasi-elastic (e,e'p) Reaction on C, Fe and Au
We report the results from a systematic study of the quasi-elastic (e,e'p)
reaction on C, Fe and Au performed at Jefferson Lab. We
have measured nuclear transparency and extracted spectral functions (corrected
for radiation) over a Q range of 0.64 - 3.25 (GeV/c) for all three
nuclei. In addition we have extracted separated longitudinal and transverse
spectral functions at Q of 0.64 and 1.8 (GeV/c) for these three nuclei
(except for Au at the higher Q). The spectral functions are
compared to a number of theoretical calculations. The measured spectral
functions differ in detail but not in overall shape from most of the
theoretical models. In all three targets the measured spectral functions show
considerable excess transverse strength at Q = 0.64 (GeV/c), which is
much reduced at 1.8 (GeV/c).Comment: For JLab E91013 Collaboration, 19 pages, 20 figures, 3 table
- …