17,715 research outputs found
Film study for a star correlator Final report
Photographic recording film evaluation for star field image processing in spacecraft environment and use in star correlato
Collaborative Educational Experiences through Higher Education-Industry Partnerships
This paper examines the perceptions of mentors and student interns from NASA's Langley Aerospace Research Summer Scholars (LARSS) program in Hampton, Virginia. Data for the current study are from student interns and mentors participating in the 2010, 10-week summer internship. Students are chosen from around the country based upon their applications and mentoring opportunities to participate in a summer program focusing on a range of specialty areas including: aeronautics; earth science research; exploration and flight; systems and concepts; systems engineering; subsonic/transonic testing; supersonic/hypersonic testing; and structures testing. This study presents information on mentors perceptions of academic preparedness brought to the workplace by student interns; student interns perceptions of how the internship helped develop key skill areas; and self-reports from student interns and their mentors about their internship experience
Method for Fabricating Piezoelectric Polymer Acoustic Sensors
A method for forming a sensor includes providing a first and a second film and bonding an internal connection tab there between. The internal connection tab is positioned between the inner surfaces of the first and second film. Then, a conductive adhesive is applied to either the tab or to the inner film surfaces such that the inner surfaces of the film and the tab are electrically connected. Finally, the films are pressed together to bond the film together with the internal connection tab in between
Radio-frequency dressing of multiple Feshbach resonances
We demonstrate and theoretically analyze the dressing of several proximate
Feshbach resonances in Rb-87 using radio-frequency (rf) radiation. We present
accurate measurements and characterizations of the resonances, and the dramatic
changes in scattering properties that can arise through the rf dressing. Our
scattering theory analysis yields quantitative agreement with the experimental
data. We also present a simple interpretation of our results in terms of
rf-coupled bound states interacting with the collision threshold.Comment: 4+ pages, 3 figures, 1 table; revised introduction & references to
reflect published versio
Effect of magnetic field on the phase transition in a dusty plasma
The formation of self-consistent crystalline structure is a well-known
phenomenon in complex plasmas. In most experiments the pressure and rf power
are the main controlling parameters in determining the phase of the system. We
have studied the effect of externally applied magnetic field on the
configuration of plasma crystals, suspended in the sheath of a radio-frequency
discharge using the Magnetized Dusty Plasma Experiment (MDPX) device.
Experiments are performed at a fixed pressure and rf power where a crystalline
structure is formed within a confining ring. The magnetic field is then
increased from 0 to 1.28 T. We report on the breakdown of the crystalline
structure with increasing magnetic field. The magnetic field affects the
dynamics of the plasma particles and first leads to a rotation of the crystal.
At higher magnetic field, there is a radial variation (shear) in the angular
velocity of the moving particles which we believe leads to the melting of the
crystal. This melting is confirmed by evaluating the variation of the pair
correlation function as a function of magnetic field.Comment: 9 pages, 5 figure
Vacuum holding fixture and method for fabricating piezoelectric polymer acoustic sensors
An apparatus and method for bonding a first film to a second film to form a sensor. The first and second films are piezoelectric films. A base section has a mating surface for holding the first film. A top section has a mating surface for holding the second film, the top section and base section being mateable together to form a cavity between the top section mating surface and the base section mating surface with the first film and the second film pressed together inside the cavity to bond the first film to the second film. An internal connection port forming mechanism forms an internal connection port between the first film and the second film when the base section and top section are mated together with the first film and the second film pressed together inside the cavity. Alternately, an internal connection tab forming mechanism can be used to form a sensor having an internal connection tab between the first and second film, instead of having an internal connection port
Ultra Wide Band Millimeter Wave Holographic 3-D Imaging of Concealed Targets on Mannequins
Ultra wide band (chirp frequency) millimeter wave “3-D” holography is a unique technique for imaging concealed targets on human subjects with extremely high lateral and depth resolution. Recent “3-D” holographic images of full size mannequins with concealed weapons illustrate the efficacy of this technique for airport security
Metal Speciation. Effects on Aquatic Toxicity
Most Water Quality Criteria for Metals Are Presently based on Total Metal Concentrations. However, for a Series of Algal Bioassays in Which Zinc and Various Chelators Were Added, Toxicity Was Not Related to Total Metal but Was Related to the Predicted Free Metal Concentration. © 1980, American Chemical Society. All Rights Reserved
Early respiratory viral infections in infants with cystic fibrosis
This article is made available for unrestricted research re-use and secondary analysis in any form or by any means with acknowledgement of the original source. These permissions are granted for the duration of the World Health Organization (WHO) declaration of COVID-19 as a global pandemic.Background
Viral infections contribute to morbidity in cystic fibrosis (CF), but the impact of respiratory viruses on the development of airway disease is poorly understood.
Methods
Infants with CF identified by newborn screening were enrolled prior to 4 months of age to participate in a prospective observational study at 4 centers. Clinical data were collected at clinic visits and weekly phone calls. Multiplex PCR assays were performed on nasopharyngeal swabs to detect respiratory viruses during routine visits and when symptomatic. Participants underwent bronchoscopy with bronchoalveolar lavage (BAL) and a subset underwent pulmonary function testing. We present findings through 8.5 months of life.
Results
Seventy infants were enrolled, mean age 3.1 ± 0.8 months. Rhinovirus was the most prevalent virus (66%), followed by parainfluenza (19%), and coronavirus (16%). Participants had a median of 1.5 viral positive swabs (range 0–10). Past viral infection was associated with elevated neutrophil concentrations and bacterial isolates in BAL fluid, including recovery of classic CF bacterial pathogens. When antibiotics were prescribed for respiratory-related indications, viruses were identified in 52% of those instances.
Conclusions
Early viral infections were associated with greater neutrophilic inflammation and bacterial pathogens. Early viral infections appear to contribute to initiation of lower airway inflammation in infants with CF. Antibiotics were commonly prescribed in the setting of a viral infection. Future investigations examining longitudinal relationships between viral infections, airway microbiome, and antibiotic use will allow us to elucidate the interplay between these factors in young children with CF
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