216 research outputs found
Reviewing the Review Boards: Why Institutional Review Board Liability Does Not Make Good Business Sense
Use of capillary electrophoresis as a method development tool for classical gel electrophoresis
Capillary electrophoresis (CE) was used to optimize the
buffer pH, ionic strength and sulfated cyclodextrin
concentrations for enantiomeric separation of piperoxan.
These enantioseparation conditions were then applied to a
classical gel electrophoresis system. Binding constants of
the sulfated beta-cyclodextrinâpiperoxan couple were
approximated using CE and the effects of organic solvents
on the system were also investigated
Mothers and Children: Designing research toward integrated care for both
In this paper we examine pragmatic corollaries to the design and implementation of Millennium Development Goals (MDG) 4 and 5. The first corollary we analyze is how the timeframe imposed on the MDGs affects choices about how to implement health care interventions to meet those goals, which we look at specifically in terms of the trade-off between strengthening a health care system or increasing mass campaigns. The second corollary is that, in the allocation of resources, those choices must often be made between providing health care interventions for certain members of the population as opposed to others. We analyze aspects of these unintentional effects of the MDGs, and then offer a model for designing research on the provision of maternal and child health that does aim to take them into account
Hydrographic data from R/V endeavor cruise #90
The final cruise of the NSF sponsored Warm Core Rings Program studied a Warm Core Ring (WCR) in the Fall of 1982 as it formed from a large northward meander of the Gulf Stream. This ring, known as 82-H or the eighth ring identified in 1982, formed over the New England Seamounts near 39.5 deg N, 65 deg W. Surveys using Expendable Bathythermographs, Conductivity-Temperature-Depth-Oxygen stations and Doppler Current Profiling provide a look at the genesis of a WCR. These measurements reveal that WCR 82-H separated from the Gulf Stream sometime between October 2-5. This ring was a typical WCR with a diameter of about 200 km and speeds in the high velocity core of the 175 cm/sec. Satellite imagery of 82-H following the cruise showed that it drifted WSW in the Slope Water region at almost 9 km/day, had at least one interaction with the Gulf Stream and was last observed on February 8, 1983 at 39 deg N, 72 deg W
Direct measurements of the Atlantic Equatorial Undercurrent
Measurements from 57 current meters suspended from anchored buoys in a network between 1.5°N and 1.5°S and from 27.5°W to 35°W in the Atlantic Ocean between February and April 1963 show speeds up to 70 cm/sec within the Equatorial Undercurrent. The bottom of the Undercurrent appears to be no deeper than 150 m; below th is dep th there is a westward-flowing current with speeds up to 25 cm/sec
Laser assisted synthesis of carbon nanoparticles with controlled viscosities for printing applications
High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5 nm to 50 nm with mean size of 18 nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12 mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerolâwater and isopropanolâwater. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fourier-transform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative method to engineer carbon nanoparticles and their potential use as a ligand-free nano-ink for ink jet printing (jetting) applications
A Reflective Gaussian Coronagraph for ExAO: Laboratory Performance
We report laboratory results of a coronagraphic test bench to assess the
intensity reduction differences between a "Gaussian" tapered focal plane
coronagraphic mask and a classical hard-edged "Top Hat" function mask at
Extreme Adaptive Optics (ExAO) Strehl ratios of ~94%. However, unlike a
traditional coronagraph design, we insert a reflective focal plane mask at 45
degree to the optical axis. We also used an intermediate secondary mask
("Mask_2") before a final image in order to block additional mask-edge
diffracted light. The test bench simulates the 8.1m Gemini North telescope. It
includes one spider vane, different mask radii (r= 1.9, 3.7, 7.4 lambda/D) and
two types of reflective focal plane masks (hard-edged "Top Hat" and "Gaussian"
tapered profiles). In order to investigate the relative performance of these
competing coronagraphic designs with regard to extra-solar planet detection
sensitivity, we utilize the simulation of realistic extra-solar planet
populations (Nielson et al. 2006). With an appropriate translation of our
laboratory results to expected telescope performance, a "Gaussian" tapered mask
radius of 3.7 lambda/D with an additional mask ("Mask_2") performs best
(highest planet detection sensitivity). For a full survey with this optimal
design, the simulation predicts ~30% more planets detected compared to a
similar sized "Top Hat" function mask with "Mask_2." Using the best design, the
point contrast ratio between the stellar PSF peak and the coronagraphic PSF at
10 lambda/D (0.4" in H band if D = 8.1m) is ~10 times higher than a classical
Lyot "Top Hat" coronagraph. Hence, we find a Gaussian apodized mask with an
additional blocking mask is a superior (~10x higher contrast) than use of a
classical Lyot coronagraph for ExAO-like Strehls.Comment: 42 pages, 12 figures, 1 table: accepted by the Publications of the
Astronomical Society of the Pacifi
Cruise summaries of Oceanus cruises 205, leg 8, and 216
A study of the upper ocean thermal and density structure in the northwestern Atlantic in 1989 compared temperature and density measurements made with Expendable Bathythermograph (XBT) and Conductivity-Temperature-Depth instruments with current data from an acoustic Doppler current profiler and satellite infrared imagery and altimetry. Two cruises were made in the spring and winter of 1989 with the goal of directly measuring the upper ocean currents and variabilty of the Gulf Stream. The XBT observations were used to extend the measured velocities geostrophically from the near-surface region to depths of 750 meters,
thereby allowing transport estimates to be made for the upper ocean. In April the measurments were compared and used with the
GEOSAT altimeter which, unfortunately, was not operating during the December cruise.Funding was provided by the National Science Foundation
through Grant No. OCE-SS-1769S
First tests of wavefront sensing with a constellation of laser guide beacons
Adaptive optics to correct current telescopes over wide fields, or future
very large telescopes over even narrow fields, will require real-time wavefront
measurements made with a constellation of laser beacons. Here we report the
first such measurements, made at the 6.5 m MMT with five Rayleigh beacons in a
2 arcmin pentagon. Each beacon is made with a pulsed beam at 532 nm, of 4 W at
the exit pupil of the projector. The return is range-gated from 20-29 km and
recorded at 53 Hz by a 36-element Shack-Hartmann sensor. Wavefronts derived
from the beacons are compared with simultaneous wavefronts obtained for
individual natural stars within or near the constellation. Observations were
made in seeing averaging 1.0 arcsec with 2/3 of the aberration measured to be
from a ground layer of mean height 380 m. Under these conditions, subtraction
of the simple instantaneous average of the five beacon wavefronts from the
stellar wavefronts yielded a 40% rms reduction in the measured modes of the
distortion over a 2 arcmin field. We discuss the use of multiple Rayleigh
beacons as an alternative to single sodium beacons on 8 m telescopes, and the
impact of the new work on the design of a multi-sodium beacon system for the 25
m Giant Magellan Telescope.Comment: 25 pages, 7 figures, uses aastex.cls, to be published in the
Astrophys.
USNS Bartlett cruise 40-B data report
A joint cruise with Dr. Michael Gregg of the Applied Physics Laboratory
at the University of Washington was conducted from 8-24 January,
1983, aboard the USNS Bartlett to study the effects of wintertime cooling
in a warm core ring. At the beginning of the cruise an XBT survey of
ring 821 (found at 40°40'N, 66°W, east of the New England Seamounts)
showed a rather confused pattern of surface temperature and salinity with
the average depth of the mixed layer about 30m. On January 16-17, a storm
passed near the ring with winds to 45 knots and temperatures below 0°C.
An XBT survey at the end of the cruise showed that vertical mixing and
cooling during the outbreak of cold air resulted in a more coherent pattern
in the surface temperature and salinity of the ring and an increase
in the thickness of the mixed layer to 180 m.Prepared for the Office of Naval Research under Contract
N00014-82-C-0019; NR 083-004
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