1,649 research outputs found
Perceptions of Family Preservation Practitioners: A Preliminary Study
This exploratory, qualitative study examined practitioners\u27 perceptions about family preservation practice. Findings reveal a wide range of identified strengths as well as the limitations of such a model. Interestingly, the most frequently identified strengths were value based rather than practice based in perspective whereas limitations were practice based. Keeping families together was the most common perceived strength but concern about children\u27s safety by keeping the family intact was a frequently reported limitation. Further, lack of support and a lack of theoretical clarity were identified as considerable limitations. Implications suggest these practitioners (mostly child welfare/mental health workers) believe in the approach for the sake of keeping families together but are concerned with endangering the child in the process and recognize the need for theoretical guidance
Some Improvements in Utilization of Flash Memory Devices
Two developments improve the utilization of flash memory devices in the face of the following limitations: (1) a flash write element (page) differs in size from a flash erase element (block), (2) a block must be erased before its is rewritten, (3) lifetime of a flash memory is typically limited to about 1,000,000 erases, (4) as many as 2 percent of the blocks of a given device may fail before the expected end of its life, and (5) to ensure reliability of reading and writing, power must not be interrupted during minimum specified reading and writing times. The first development comprises interrelated software components that regulate reading, writing, and erasure operations to minimize migration of data and unevenness in wear; perform erasures during idle times; quickly make erased blocks available for writing; detect and report failed blocks; maintain the overall state of a flash memory to satisfy real-time performance requirements; and detect and initialize a new flash memory device. The second development is a combination of hardware and software that senses the failure of a main power supply and draws power from a capacitive storage circuit designed to hold enough energy to sustain operation until reading or writing is completed
GPS/MEMS IMU/Microprocessor Board for Navigation
A miniaturized instrumentation package comprising a (1) Global Positioning System (GPS) receiver, (2) an inertial measurement unit (IMU) consisting largely of surface-micromachined sensors of the microelectromechanical systems (MEMS) type, and (3) a microprocessor, all residing on a single circuit board, is part of the navigation system of a compact robotic spacecraft intended to be released from a larger spacecraft [e.g., the International Space Station (ISS)] for exterior visual inspection of the larger spacecraft. Variants of the package may also be useful in terrestrial collision-detection and -avoidance applications. The navigation solution obtained by integrating the IMU outputs is fed back to a correlator in the GPS receiver to aid in tracking GPS signals. The raw GPS and IMU data are blended in a Kalman filter to obtain an optimal navigation solution, which can be supplemented by range and velocity data obtained by use of (l) a stereoscopic pair of electronic cameras aboard the robotic spacecraft and/or (2) a laser dynamic range imager aboard the ISS. The novelty of the package lies mostly in those aspects of the design of the MEMS IMU that pertain to controlling mechanical resonances and stabilizing scale factors and biases
Microwave Continuum Emission and Dense Gas Tracers in NGC 3627: Combining Jansky VLA and ALMA Observations
We present Karl G. Jansky Very Large Array (VLA) Ka band (33 GHz) and Atacama
Large Millimeter Array (ALMA) Band 3 (94.5 GHz) continuum images covering the
nucleus and two extranuclear star-forming regions within the nearby galaxy NGC
3627 (M 66), observed as part of the Star Formation in Radio Survey (SFRS).
Both images achieve an angular resolution of 2\arcsec, allowing us to
map the radio spectral indices and estimate thermal radio fractions at a linear
resolution of 90 pc at the distance of NGC 3627. The thermal fraction
at 33 GHz reaches unity at and around the peaks of each HII region; we
additionally observed the spectral index between 33 and 94.5 GHz to become both
increasingly negative and positive away from the peaks of the HII regions,
indicating an increase of non-thermal extended emission from diffusing
cosmic-ray electrons and the possible presence of cold dust, respectively.
While the ALMA observations were optimized for collecting continuum data, they
also detected line emission from the transitions of HCN and
HCO. The peaks of dense molecular gas traced by these two spectral lines
are spatially offset from the peaks of the 33 and 94.5 GHz continuum emission
for the case of the extranuclear star-forming regions, indicating that our data
reach an angular resolution at which one can spatially distinguish sites of
recent star formation from the sites of future star formation. Finally, we find
trends of decreasing dense gas fraction and velocity dispersion with increasing
star formation efficiency among the three regions observed, indicating that the
dynamical state of the dense gas, rather than its abundance, plays a more
significant role in the star formation process.Comment: 9 pages, 5 figures, accepted for publication in Ap
Complex Radio Spectral Energy Distributions in Luminous and Ultraluminous Infrared Galaxies
We use the Expanded Very Large Array to image radio continuum emission from
local luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in 1 GHz
windows centered at 4.7, 7.2, 29, and 36 GHz. This allows us to probe the
integrated radio spectral energy distribution (SED) of the most energetic
galaxies in the local universe. The 4-8 GHz flux densities agree well with
previous measurements. They yield spectral indices \alpha \approx -0.67 (where
F_\nu \propto \nu^\alpha) with \pm 0.15 (1\sigma) scatter, typical of
nonthermal (synchrotron) emission from star-forming galaxies. The contrast of
our 4-8 GHz data with literature 1.5 and 8.4 GHz flux densities gives further
evidence for curvature of the radio SED of U/LIRGs. The SED appears flatter
near \sim 1 GHz than near \sim 6 GHz, suggesting significant optical depth
effects at the lower frequencies. The high frequency (28-37 GHz) flux densities
are low compared to extrapolations from the 4-8 GHz data. We confirm and extend
to higher frequency a previously observed deficit of high frequency radio
emission for luminous starburst galaxies.Comment: 7 pages, 3 figures, 1 table, accepted for publication in the EVLA
Special Issue of ApJ Letter
Carbon Monitoring System Flux Estimation and Attribution: Impact of ACOS-GOSAT X(CO2) Sampling on the Inference of Terrestrial Biospheric Sources and Sinks
Using an Observing System Simulation Experiment (OSSE), we investigate the impact of JAXA Greenhouse gases Observing SATellite 'IBUKI' (GOSAT) sampling on the estimation of terrestrial biospheric flux with the NASA Carbon Monitoring System Flux (CMS-Flux) estimation and attribution strategy. The simulated observations in the OSSE use the actual column carbon dioxide (X(CO2)) b2.9 retrieval sensitivity and quality control for the year 2010 processed through the Atmospheric CO2 Observations from Space algorithm. CMS-Flux is a variational inversion system that uses the GEOS-Chem forward and adjoint model forced by a suite of observationally constrained fluxes from ocean, land and anthropogenic models. We investigate the impact of GOSAT sampling on flux estimation in two aspects: 1) random error uncertainty reduction and 2) the global and regional bias in posterior flux resulted from the spatiotemporally biased GOSAT sampling. Based on Monte Carlo calculations, we find that global average flux uncertainty reduction ranges from 25% in September to 60% in July. When aggregated to the 11 land regions designated by the phase 3 of the Atmospheric Tracer Transport Model Intercomparison Project, the annual mean uncertainty reduction ranges from 10% over North American boreal to 38% over South American temperate, which is driven by observational coverage and the magnitude of prior flux uncertainty. The uncertainty reduction over the South American tropical region is 30%, even with sparse observation coverage. We show that this reduction results from the large prior flux uncertainty and the impact of non-local observations. Given the assumed prior error statistics, the degree of freedom for signal is approx.1132 for 1-yr of the 74 055 GOSAT X(CO2) observations, which indicates that GOSAT provides approx.1132 independent pieces of information about surface fluxes. We quantify the impact of GOSAT's spatiotemporally sampling on the posterior flux, and find that a 0.7 gigatons of carbon bias in the global annual posterior flux resulted from the seasonally and diurnally biased sampling when using a diagonal prior flux error covariance
Microbiological Lessons Learned from the Space Shuttle
After 30 years of being the centerpiece of NASA s human spacecraft, the Space Shuttle will retire. This highly successful program provided many valuable lessons for the International Space Station (ISS) and future spacecraft. Major microbiological risks to crewmembers include food, water, air, surfaces, payloads, animals, other crewmembers, and ground support personnel. Adverse effects of microorganisms are varied and can jeopardize crew health and safety, spacecraft systems, and mission objectives. Engineering practices and operational procedures can minimize the negative effects of microorganisms. To minimize problems associated with microorganisms, appropriate steps must begin in the design phase of new spacecraft or space habitats. Spacecraft design must include requirements to control accumulation of water including humidity, leaks, and condensate on surfaces. Materials used in habitable volumes must not contribute to microbial growth. Use of appropriate materials and the implementation of robust housekeeping that utilizes periodic cleaning and disinfection will prevent high levels of microbial growth on surfaces. Air filtration can ensure low levels of bioaerosols and particulates in the breathing air. The use of physical and chemical steps to disinfect drinking water coupled with filtration can provide safe drinking water. Thorough preflight examination of flight crews, consumables, and the environment can greatly reduce pathogens in spacecraft. The advances in knowledge of living and working onboard the Space Shuttle formed the foundation for environmental microbiology requirements and operations for the International Space Station (ISS) and future spacecraft. Research conducted during the Space Shuttle Program resulted in an improved understanding of the effects of spaceflight on human physiology, microbial properties, and specifically the host-microbe interactions. Host-microbe interactions are substantially affected by spaceflight. Astronaut immune functions were found to be altered. Selected microorganisms were found to become more virulent during spaceflight. The increased knowledge gained on the Space Shuttle resulted in further studies of the host-microbe interactions on the ISS to determine if countermeasures were necessary. Lessons learned from the Space Shuttle Program were integrated into the ISS resulting in the safest space habitat to date
Multiplex PCR and Next Generation Sequencing for the Non-Invasive Detection of Bladder Cancer
Highly sensitive and specific urine-based tests to detect either primary or recurrent bladder
cancer have proved elusive to date. Our ever increasing knowledge of the genomic aberrations in bladder cancer should enable the development of such tests based on urinary DNA
Fulde-Ferrell-Larkin-Ovchinnikov State in Heavy Fermion Superconductors
The Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state is a novel superconducting
state in a strong magnetic field characterized by the formation of Cooper pairs
with nonzero total momentum (k \uparrow, -k+q \downarrow), instead of the
ordinary BCS pairs (k \uparrow, -k \downarrow). A fascinating aspect of the
FFLO state is that it exhibits inhomogeneous superconducting phases with a
spatially oscillating order parameter and spin polarization. The FFLO state has
been of interest in various research fields, not only in superconductors in
solid state physics, but also in neutral Fermion superfluid of ultracold atomic
gases and in color superconductivity in high energy physics. In spite of
extensive studies of various superconductors, there has been no undisputed
experimental verification of the FFLO state, mainly because of the very
stringent conditions required of the superconducting materials. Among several
classes of materials, certain heavy fermion and organic superconductors are
believed to provide conditions that are favorable to the formation of the FFLO
state. This review presents recent experimental and theoretical developments of
the FFLO state mainly in heavy fermion superconductors. In particular we
address the recently discovered quasi-two-dimensional superconductor CeCoIn_5,
which is a strong candidate for the formation of the FFLO state.Comment: 17 pages, 12 figures with jpsf2.cls, to be published in J. Phys. Soc.
Jpn. (Special Topics - Frontiers of Novel Superconductivity in Heavy Fermion
Compounds
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