10,168 research outputs found
A balloon-borne 1 meter telescope for far-infrared astronomy
The flight of a balloon-borne one-meter telescope for infrared astronomy in the wavelength interval of 40 to 240 microns is discussed. The gyro-stabilized telescope mapped the intensity of the far infrared radiation from NGC 7538, Mars, the Orion Nebula, and W3 with a resolution of one minute and from selected regions of these sources with a resolution of 30 seconds. The infrared detection is described and its capabilities are analyzed. The instrumentation, orientation system, and modes of observation of the telescope are defined
Effect of forward motion on engine noise
Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground
Diffraction and the Pomeron
Recent experimental results on inclusive diffractive scattering and on
exclusive vector meson production are reviewed. The dynamical picture of hard
diffraction emerging in perturbative QCD is highlighted.Comment: 25 pages, 21 postscript figures, contribution to the XIX
International Symposium on Lepton and Photon Interactions at High Energies,
Stanford University, August 9-14, 199
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Women's interpretation of and responses to potential gynaecological cancer symptoms: a qualitative interview study
OBJECTIVE: To explore women's experiences of symptoms potentially indicative of gynaecological cancer in a community-based sample without imposing a cancer perspective.
DESIGN: A qualitative interview study with thematic analysis of transcripts.
PARTICIPANTS: 26 women aged ≥30 years, who had experienced a symptom that might indicate gynaecological cancer in the past 3 months, were recruited using a screening questionnaire distributed online and in community settings.
SETTING: London, UK.
RESULTS: Women attributed gynaecological symptoms to existing illnesses/conditions or considered themselves to be predisposed to them, either through their 'genes' or previous personal experience. Normalising symptoms by attributing them to demographic characteristics (e.g., age, sex) was common, as was considering them a side effect of hormonal contraception. When women raised cancer as a possible cause, they often dismissed it as unlikely. Responses to symptoms included self-management (e.g., self-medicating, making lifestyle changes), adopting a 'lay system of care', or consulting a healthcare professional. Triggers to help-seeking included persistent, painful or debilitating symptoms, concern about symptom seriousness, and feeling that help-seeking was legitimised. Barriers to help-seeking included lack of concern, vague symptoms, unusual symptom location, competing time demands, previous negative experiences with the healthcare system, and not wanting to be perceived as a time-waster.
CONCLUSIONS: Attributions of symptoms potentially indicative of a gynaecological cancer were varied, but most often involved women fitting symptoms into their expectations of what was 'normal'. Normalising acted as a barrier to seeking help from a healthcare professional, alongside competing time demands and negative attitudes towards help-seeking. These barriers may lead to later diagnosis and poorer cancer survival. Our findings could be used to inform the development of interventions to encourage appropriate help-seeking
Infrared Emission from the Radio Supernebula in NGC 5253: A Proto-Globular Cluster?
Hidden from optical view in the starburst region of the dwarf galaxy NGC 5253
lies an intense radio source with an unusual spectrum which could be
interpreted variously as nebular gas ionized by a young stellar cluster or
nonthermal emission from a radio supernova or an AGN. We have obtained 11.7 and
18.7 micron images of this region at the Keck Telescope and find that it is an
extremely strong mid-infrared emitter. The infrared to radio flux ratio rules
out a supernova and is consistent with an HII region excited by a dense cluster
of young stars. This "super nebula" provides at least 15% of the total
bolometric luminosity of the galaxy. Its excitation requires 10^5-10^6 stars,
giving it the total mass and size (1-2 pc diameter) of a globular cluster.
However, its high obscuration, small size, and high gas density all argue that
it is very young, no more than a few hundred thousand years old. This may be
the youngest globular cluster yet observed.Comment: 6 pages, 2 color figures, Submitted to the ApJL, Revised 4/6/01 based
on referee's comment
Elementary particles of conventional field theory as Regge poles. III
It is shown that an elementary particle of conventional field theory may, under certain conditions, lie on a Regge trajectory. These conditions are that the system contain a "nonsense" channel at the angular momentum of the particle and that the Born approximation scattering amplitude factor in a well-defined way. They are satisfied by a spin ½ fermion interacting through a conserved current with a spin one neutral boson. The particle in question is the fermion
Interaction of small size wave packet with hadron target
We calculate in QCD the cross section for the scattering of an energetic
small-size wave packet off a hadron target. We use our results to study the
small- behaviour of , the distribution over cross
section for the pion, in the leading -order.Comment: Revised version of the report CEBAF-TH-96-0
Application of dispersion relations to low-energy meson-nucleon scattering
Relativistic dispersion relations are used to derive equations for low-energy S-, P-, and D-wave meson-nucleon scattering under the assumption that the (3,3) resonance dominates the dispersion integrals. The P-wave equations so obtained differ only slightly from those of the static fixed-source theory. The conclusions of the static theory are re-examined in the light of their new derivation
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