1,019 research outputs found
Remote sensing: Physical principles, sensors and products, and the LANDSAT
Techniques of data acquisition by remote sensing are introduced in this teaching aid. The properties of the elements involved (radiant energy, topograph, atmospheric attenuation, surfaces, and sensors) are covered. Radiometers, photography, scanners, and radar are described as well as their products. Aspects of the LANDSAT system examined include the characteristics of the satellite and its orbit, the multispectral band scanner, and the return beam vidicon. Pixels (picture elements), pattern registration, and the characteristics, reception, and processing of LANDSAT imagery are also considered
Enhanced dynamics in fusion of neutron-rich oxygen nuclei at above-barrier energies
Above-barrier fusion cross-sections for an isotopic chain of oxygen isotopes
with A=16-19 incident on a C target are presented. Experimental data are
compared with both static and dynamical microscopic calculations. These
calculations are unable to explain the 37\% increase in the average
above-barrier fusion cross-section observed for O as compared to
-stable oxygen isotopes. This result suggests that for neutron-rich
nuclei existing time-dependent Hartree-Fock calculations underpredict the role
of dynamics at near-barrier energies. High-quality measurement of above-barrier
fusion for an isotopic chain of increasingly neutron-rich nuclei provides an
effective means to probe this fusion dynamics.Comment: 6 pages, 4 figure
Beyond Rigor and Relevance Towards Responsibility and Reverberation: Information Systems Research That Really Matters
This paper is an outcome of a panel discussion that was held during the 2005 International Conference on Information Systems (ICIS). The panel, titled, IS Research that Really Matters: Beyond the IS Rigor - Relevance Debate, was organized to foster a discussion on conducting IS research that is significant, in terms of impact, and responsible to the needs of stakeholders. To this end, panel members were asked to push the debate on IS research beyond the traditional arguments of rigor and relevance in research towards IS research that reverberates and is responsible. In doing so, the panel members shared their views on the definition of significant research, who are the stakeholders of IS research and what are their needs, and how do we move the field ahead
Influence of additional neutrons on the fusion cross-section beyond the N=8 shell
Fusion enhancement for neutron-rich isotopes of oxygen on carbon nuclei was
probed. To measure the fusion cross-section a O beam accelerated to
E/A=2.7 MeV bombarded the active-target detector MuSIC@Indiana with a
fill gas of CH. Examination of the average fusion cross-section over the
interval 12 MeV E 17 MeV for O + C
reveals that while even isotopes of oxygen exhibit essentially the same
cross-section, the cross-section for odd isotopes can be either enhanced or
suppressed relative to the even A members of the isotopic chain. Theoretical
models fail to explain the observed experimental results.Comment: 6 pages, 4 figure
Comparison of diverse methods for the correction of atmospheric effects on LANDSAT and SKYLAB images
Earth's atmosphere reduces a sensors ability in currently discriminating targets. Using radiometric correction to reduce the atmospheric effects may improve considerably the performance of an automatic image interpreter. Several methods for radiometric correction from the open literature are compared leading to the development of an atmospheric correction system
Angular Dependence in Proton-Proton Correlation Functions in Central and Reactions
The angular dependence of proton-proton correlation functions is studied in
central and nuclear reactions at E=80
MeV/A. Measurements were performed with the HiRA detector complemented by the
4 Array at NSCL. A striking angular dependence in the laboratory frame is
found within p-p correlation functions for both systems that greatly exceeds
the measured and expected isospin dependent difference between the neutron-rich
and neutron-deficient systems. Sources measured at backward angles reflect the
participant zone of the reaction, while much larger sources observed at forward
angles reflect the expanding, fragmenting and evaporating projectile remnants.
The decrease of the size of the source with increasing momentum is observed at
backward angles while a weaker trend in the opposite direction is observed at
forward angles. The results are compared to the theoretical calculations using
the BUU transport model.Comment: 8 pages, 3 figures, submitted to PR
Prehypertension and Endothelial Progenitor Cell Function.
Prehypertension is associated with significant damage to the coronary vasculature and increased rates of adverse cardiovascular events. Circulating endothelial progenitor cells (EPCs) are critical to vascular repair and the formation of new blood vessels. We tested the hypothesis that prehypertension is associated with EPC dysfunction. Peripheral blood samples were collected from 83 middle-aged and older adults (51 M/32 F): 40 normotensive (age 53±2 yr; BP 111/74±1/1 mmHg) and 43 prehypertensive (54±2; 128/77±1/1 mmHg). EPCs were isolated from peripheral blood and EPC colony-forming capacity (colony-forming unit assay), migratory activity (Boyden chamber) and apoptotic susceptibility (active caspase-3 concentrations) were determined. There were no significant differences in either the number of EPC CFUs (10±2 vs. 9±1), EPC migration (1165±82 vs. 1120±84 fluorescent units), or active intracellular caspase-3 concentrations (2.7±0.3 vs. 2.3±0.2 ng/mL) between the normotensive and prehypertensive groups. When groups were stratified into low prehypertension (n=27; systolic BP: 120–129 mmHg) and high prehypertension (n=16; 130–139 mmHg), it was found that EPCs from the high prehypertensive group produced fewer (~65%, P\u3c0.05) CFUs compared with the low prehypertensive (4±1 vs. 12±2) and normotensive adults. In conclusion, EPC colonyforming capacity is impaired only in prehypertensive adults with systolic BP greater than 130 mmHg. Prehypertension is not associated with migratory dysfunction or enhanced apoptosis of EPCs
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