1,777 research outputs found
A Single-armed Manta-board as a New Diver-controlled Planing Board and Its Use for Underwater Surveys
Due to inadequacies of previous underwater towing techniques and the special needs of a recent underwater survey, a modified mania-board technique was developed. With this new technique, the diver holds on to the manta-board with one arm; consequently, the board is referred to as a single-armed manta-board (sam-board). The sam-board proved inexpensive and highly maneuverable, allowing the divers to freely collect samples or record information. Through some experimenting with the board and changing some of the variables, such as rope lengths, towing speeds, etc., a highly efficient towing method can be achieved. Preplanning and strict diving safety procedures must, however, be implemented to assure efficiency. This paper presents the materials, guidelines for board construction, equipment, and preplanning and diving safety procedures necessary for the sam-board towing operation
Relationships Among Disease, Social Support, and Perceived Health: A Lifespan Approach
We examined the relationship between the cumulative presence of major disease (cancer, stroke, diabetes, heart disease, and hypertension), social support, and selfâreported general and emotional wellâbeing in a community representative sample of predominantly White and African American respondents (N = 1349). Across all ages, greater presence of disease predicted poorer reported general health, and predicted lower emotional wellâbeing for respondents 40 and above. In contrast, social support predicted betterâreported general and emotional wellâbeing. We predicted that different types of social support (blood relatives, children, friends, community members) would be relatively more important for health in different age groups based on a lifespan or life stage model. This hypothesis was supported; across all ages, social support was related to better reported general and emotional health, but sources of support differed by age. Broadly, those in younger age groups tended to list familial members as their strongest sources of support, whereas older group members listed their friends and community members. As a whole, social support mediated the effect of disease on reported wellâbeing, however, moderated mediation by type of support was not significant. The results are consistent with a lifespan approach to changing social ties throughout the life course.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116357/1/ajcp9758.pd
Dislocation Emission around Nanoindentations on a (001) fcc Metal Surface Studied by STM and Atomistic Simulations
We present a combined study by Scanning Tunneling Microscopy and atomistic
simulations of the emission of dissociated dislocation loops by nanoindentation
on a (001) fcc surface. The latter consist of two stacking-fault ribbons
bounded by Shockley partials and a stair-rod dislocation. These dissociated
loops, which intersect the surface, are shown to originate from loops of
interstitial character emitted along the directions and are usually
located at hundreds of angstroms away from the indentation point. Simulations
reproduce the nucleation and glide of these dislocation loops.Comment: 10 pages, 4 figure
The cap-snatching SFTSV endonuclease domain is an antiviral target
Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne virus with 12%-30% case mortality rates and is related to the Heartland virus (HRTV) identified in the United States. Together, SFTSV and HRTV are emerging segmented, negative-sense RNA viral (sNSV) pathogens with potential global health impact. Here, we characterize the amino-terminal cap-snatching endonuclease domain of SFTSV polymerase (L) and solve a 2.4-Ă
X-ray crystal structure. While the overall structure is similar to those of other cap-snatching sNSV endonucleases, differences near the C terminus of the SFTSV endonuclease suggest divergence in regulation. Influenza virus endonuclease inhibitors, including the US Food and Drug Administration (FDA) approved Baloxavir (BXA), inhibit the endonuclease activity in in vitro enzymatic assays and in cell-based studies. BXA displays potent activity with a half maximal inhibitory concentration (I
SHCal13 Southern Hemisphere calibration, 0â50,000 years cal BP
The Southern Hemisphere SHCal04 radiocarbon calibration curve has been updated with the addition of new data sets extending measurements to 2145 cal BP and including the ANSTO Younger Dryas Huon pine data set. Outside the range of measured data, the curve is based upon the Northern Hemisphere data sets as presented in IntCal13, with an interhemispheric offset averaging 43 Âą 23 yr modeled by an autoregressive process to represent the short-term correlations in the offset
Spectral Typing of Late Type Stellar Companions to Young Stars from Low Dispersion Near-Infrared Integral Field Unit Data
We used the Project 1640 near-infrared coronagraph and integral field
spectrograph to observe 19 young solar type stars. Five of these stars are
known binary stars and we detected the late-type secondaries and were able to
measure their JH spectra with a resolution of R\sim30. The reduced, extracted,
and calibrated spectra were compared to template spectra from the IRTF spectral
library. With this comparison we test the accuracy and consistency of spectral
type determination with the low-resolution near-infrared spectra from P1640.
Additionally, we determine effective temperature and surface gravity of the
companions by fitting synthetic spectra calculated with the PHOENIX model
atmosphere code. We also present several new epochs of astrometry of each of
the systems. Together these data increase our knowledge and understanding of
the stellar make up of these systems. In addition to the astronomical results,
the analysis presented helps validate the Project 1640 data reduction and
spectral extraction processes and the utility of low-resolution, near-infrared
spectra for characterizing late-type companions in multiple systems.Comment: Accepted to Astronomical Journal, 25 pages, 8 figure
Busy Streets Theory: The Effects of Communityâ engaged Greening on Violence
Lack of maintenance on vacant neighborhood lots is associated with higher levels of depression, anxiety, and stress for nearby residents. Overgrown grasses and dense brush provide hiding spots for criminals and space to conduct illicit activities. This study builds upon previous research by investigating greening programs that engage community members to conduct routine maintenance on vacant lots within their neighborhoods. The Clean & Green program is a communityâ based solution that facilitates residentâ driven routine maintenance of vacant lots in a midsized, Midwestern city. We use mixed effects regression to compare assault and violent crime counts on streets where vacant lot(s) are maintained by community members (NĂ =Ă 216) versus streets where vacant lots were left alone (NĂ =Ă 446) over a 5â year timeframe (2009â 2013). Street segments with vacant lots maintained through the Clean & Green program had nearly 40% fewer assaults and violent crimes than street segments with vacant, abandoned lots, which held across 4Ă years with a large sample and efforts to test counterfactual explanations. Communityâ engaged greening programs may not only provide a solution to vacant lot maintenance, but also work as a crime prevention or reduction strategy. Engaging the community to maintain vacant lots in their neighborhood reduces costs and may increase the sustainability of the program.HighlightsBlighted and abandoned properties generate substantial costs and risk for postindustrial cities.Communityâ engaged maintenance of properties can reduce blight and increase social cohesion.We compare levels of crime on streets with â greenedâ versus unmaintained vacant lots.Community greened lots may reduce blight and crime at lower cost to cities and build social capital.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146412/1/ajcp12270_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146412/2/ajcp12270.pd
A cryptic pocket in Ebola VP35 allosterically controls RNA binding
Protein-protein and protein-nucleic acid interactions are often considered difficult drug targets because the surfaces involved lack obvious druggable pockets. Cryptic pockets could present opportunities for targeting these interactions, but identifying and exploiting these pockets remains challenging. Here, we apply a general pipeline for identifying cryptic pockets to the interferon inhibitory domain (IID) of Ebola virus viral protein 35 (VP35). VP35 plays multiple essential roles in Ebola\u27s replication cycle but lacks pockets that present obvious utility for drug design. Using adaptive sampling simulations and machine learning algorithms, we predict VP35 harbors a cryptic pocket that is allosterically coupled to a key dsRNA-binding interface. Thiol labeling experiments corroborate the predicted pocket and mutating the predicted allosteric network supports our model of allostery. Finally, covalent modifications that mimic drug binding allosterically disrupt dsRNA binding that is essential for immune evasion. Based on these results, we expect this pipeline will be applicable to other proteins
A New High Contrast Imaging Program at Palomar Observatory
We describe a new instrument that forms the core of a long-term high contrast
imaging program at the 200-inch Hale Telescope at Palomar Observatory. The
primary scientific thrust is to obtain images and low-resolution spectroscopy
of brown dwarfs and young Jovian mass exoplanets in the vicinity of stars
within 50 parsecs of the Sun. The instrument is a microlens-based integral
field spectrograph integrated with a diffraction limited, apodized-pupil Lyot
coronagraph, mounted behind the Palomar adaptive optics system. The
spectrograph obtains imaging in 23 channels across the J and H bands (1.06 -
1.78 microns). In addition to obtaining spectra, this wavelength resolution
allows suppression of the chromatically dependent speckle noise, which we
describe. We have recently installed a novel internal wave front calibration
system that will provide continuous updates to the AO system every 0.5 - 1.0
minutes by sensing the wave front within the coronagraph. The Palomar AO system
is undergoing an upgrade to a much higher-order AO system ("PALM-3000"): a
3388-actuator tweeter deformable mirror working together with the existing
241-actuator mirror. This system will allow correction with subapertures as
small as 8cm at the telescope pupil using natural guide stars. The coronagraph
alone has achieved an initial dynamic range in the H-band of 2 X 10^-4 at 1
arcsecond, without speckle noise suppression. We demonstrate that spectral
speckle suppression is providing a factor of 10-20 improvement over this
bringing our current contrast at an arcsecond to ~2 X 10^-5. This system is the
first of a new generation of apodized pupil coronagraphs combined with
high-order adaptive optics and integral field spectrographs (e.g. GPI, SPHERE,
HiCIAO), and we anticipate this instrument will make a lasting contribution to
high contrast imaging in the Northern Hemisphere for years.Comment: Accepted to PASP: 12 pages, 12 figure
Electric Field Conjugation with the Project 1640 coronagraph
The Project 1640 instrument on the 200-inch Hale telescope at Palomar
Observatory is a coronagraphic instrument with an integral field spectrograph
at the back end, designed to find young, self-luminous planets around nearby
stars. To reach the necessary contrast for this, the PALM-3000 adaptive optics
system corrects for fast atmospheric speckles, while CAL, a phase-shifting
interferometer in a Mach-Zehnder configuration, measures the quasistatic
components of the complex electric field in the pupil plane following the
coronagraphic stop. Two additional sensors measure and control low-order modes.
These field measurements may then be combined with a system model and data
taken separately using a white-light source internal to the AO system to
correct for both phase and amplitude aberrations. Here, we discuss and
demonstrate the procedure to maintain a half-plane dark hole in the image plane
while the spectrograph is taking data, including initial on-sky performance.Comment: 9 pages, 7 figures, in Proceedings of SPIE, 8864-19 (2013
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