8 research outputs found
Testing the efficacy of an ergonomic lifting aid at diminishing muscular fatigue in women over a prolonged period of lifting
a b s t r a c t A personal lift assist device (PLAD) was designed with passive elastic elements that act with a similar line of action to the spine muscles and reduce the extension moment experienced during lifting activities. The purpose of this paper was to evaluate the device's ability to reduce fatigue during a repetitive lifting task. Women (n ¼ 12) lifted a box load representing 20% maximal extensor strength repetitively (12 lift/ lowers per minute) for 45 min while electromyography (EMG) was recorded from the lumbar and thoracic erector spinae, and cardiovascular measures were monitored. Subjects were also tested on strength and endurance tests prior to, and after lifting. The increase in EMG RMS amplitude from the start until the end of the lifting session was significantly lower when wearing the PLAD for the TES (91% vs 3%) and the LES (104% vs 16%). The median frequency (MF) drop was also significantly lower when wearing the PLAD for TES and LES. The PLAD delayed the onset of fatigue in women by requiring less muscular effort. Relevance to industry There are numerous industries that still require repetitive manual materials handling tasks to be performed by humans. Repetitive lifting fatigues the musculature involved and may lead to an increased risk of injury. The PLAD reduced fatigue on several measures. This device appears to have potential for industries where women perform repetitive, fatiguing lifts
Local Lyman Break Galaxy Analogs: The Impact of Massive Star-forming Clumps on the Interstellar Medium and the Global Structure of Young, Forming Galaxies
We present HST UV/optical imaging, Spitzer mid-IR photometry, and optical
spectroscopy of a sample of 30 low-redshift (z=0.1-0.3) galaxies chosen from
SDSS/GALEX to be accurate local analogs of the high-z Lyman Break Galaxies. The
Lyman Break Analogs (LBAs) are similar in mass, metallicity, dust, SFR, size
and gas velocity dispersion, thus enabling a detailed investigation of
processes that are important at high-z. The optical emission line properties of
LBAs are also similar to those of LBGs, indicating comparable conditions in
their ISM. In the UV, LBAs are characterized by complexes of massive
star-forming "clumps", while in the optical they most often show evidence for
(post-)mergers/interactions. In 6 cases, we find an extremely massive (>10^9
Msun) compact (R~100 pc) dominant central object (DCO). The DCOs are
preferentially found in LBAs with the highest mid-IR luminosities and
correspondingly high SFRs (15-100 Msun/yr). We show that the massive SF clumps
(including the DCOs) have masses much larger than the nuclear super star
clusters seen in normal late type galaxies. However, the DCOs have masses,
sizes, and densities similar to the excess-light/central-cusps seen in typical
elliptical galaxies with masses similar to the LBA galaxies. We suggest that
the DCOs form in present-day examples of the dissipative mergers at high
redshift that are believed to have produced the central-cusps in local
ellipticals. More generally, the properties of the LBAs are consistent with the
idea that instabilities in a gas-rich disk lead to very massive star-forming
clumps that eventually coalesce to form a spheroid. We speculate that the DCOs
are too young at present to be growing a supermassive black hole because they
are still in a supernova-dominated outflow phase.Comment: The Astrophysical Journal, In Press (22 pages, 16 figures). For the
full version with high-resolution colour figures, see:
http://www.mpa-garching.mpg.de/~overzier/Overzier_LBApaper09.pd
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies,
expounded a compelling and poetic vision for the future of astronomy, calling
for an infrared-optimized space telescope with an aperture of at least .
With the support of their governments in the US, Europe, and Canada, 20,000
people realized that vision as the James Webb Space Telescope. A
generation of astronomers will celebrate their accomplishments for the life of
the mission, potentially as long as 20 years, and beyond. This report and the
scientific discoveries that follow are extended thank-you notes to the 20,000
team members. The telescope is working perfectly, with much better image
quality than expected. In this and accompanying papers, we give a brief
history, describe the observatory, outline its objectives and current observing
program, and discuss the inventions and people who made it possible. We cite
detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space
Telescope Overview, 29 pages, 4 figure
Astronomical Software Wants To Be Free: A Manifesto
Astronomical software is now a fact of daily life for all hands-on members of
our community. Purpose-built software for data reduction and modeling tasks
becomes ever more critical as we handle larger amounts of data and simulations.
However, the writing of astronomical software is unglamorous, the rewards are
not always clear, and there are structural disincentives to releasing software
publicly and to embedding it in the scientific literature, which can lead to
significant duplication of effort and an incomplete scientific record. We
identify some of these structural disincentives and suggest a variety of
approaches to address them, with the goals of raising the quality of
astronomical software, improving the lot of scientist-authors, and providing
benefits to the entire community, analogous to the benefits provided by open
access to large survey and simulation datasets. Our aim is to open a
conversation on how to move forward. We advocate that: (1) the astronomical
community consider software as an integral and fundable part of facility
construction and science programs; (2) that software release be considered as
integral to the open and reproducible scientific process as are publication and
data release; (3) that we adopt technologies and repositories for releasing and
collaboration on software that have worked for open-source software; (4) that
we seek structural incentives to make the release of software and related
publications easier for scientist-authors; (5) that we consider new ways of
funding the development of grass-roots software; (6) and that we rethink our
values to acknowledge that astronomical software development is not just a
technical endeavor, but a fundamental part of our scientific practice
Recommended from our members
Astronomical Software Wants To Be Free: A Manifesto
Astronomical software is now a fact of daily life for all hands-on members of
our community. Purpose-built software for data reduction and modeling tasks
becomes ever more critical as we handle larger amounts of data and simulations.
However, the writing of astronomical software is unglamorous, the rewards are
not always clear, and there are structural disincentives to releasing software
publicly and to embedding it in the scientific literature, which can lead to
significant duplication of effort and an incomplete scientific record. We
identify some of these structural disincentives and suggest a variety of
approaches to address them, with the goals of raising the quality of
astronomical software, improving the lot of scientist-authors, and providing
benefits to the entire community, analogous to the benefits provided by open
access to large survey and simulation datasets. Our aim is to open a
conversation on how to move forward. We advocate that: (1) the astronomical
community consider software as an integral and fundable part of facility
construction and science programs; (2) that software release be considered as
integral to the open and reproducible scientific process as are publication and
data release; (3) that we adopt technologies and repositories for releasing and
collaboration on software that have worked for open-source software; (4) that
we seek structural incentives to make the release of software and related
publications easier for scientist-authors; (5) that we consider new ways of
funding the development of grass-roots software; (6) and that we rethink our
values to acknowledge that astronomical software development is not just a
technical endeavor, but a fundamental part of our scientific practice
The James Webb Space Telescope Mission
Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit