3,116 research outputs found
Study of techniques and applications of satellite imagery to small scale mapping
There are no author-identified significant results in this report
Cartographic research in EREP program for small scale mapping
The author has identified the following significant results. Skylab photography is suitable for producing planimetric maps with graphical representation of landform at scales up to 1:100,000. It cannot supply all the detail necessary for maps at this scale, but it may be used to produce a sound framework which can be completed by detail from other sources. Its principal cartographic use is for original mapping of undeveloped areas of the world, but it would also be useful for the revision of existing maps and for monitoring extensive urban changes
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The potential of 1 h refractivity changes from an operational C-band magnetron-based radar for numerical weather prediction validation and data assimilation
Refractivity changes (ΔN) derived from radar ground clutter returns serve as a proxy for near-surface humidity changes (1 N unit ≡ 1% relative humidity at 20 °C). Previous studies have indicated that better humidity observations should improve forecasts of convection initiation. A preliminary assessment of the potential of refractivity retrievals from an operational magnetron-based C-band radar is presented. The increased phase noise at shorter wavelengths, exacerbated by the unknown position of the target within the 300 m gate, make it difficult to obtain absolute refractivity values, so we consider the information in 1 h changes. These have been derived to a range of 30 km with a spatial resolution of ∼4 km; the consistency of the individual estimates (within each 4 km × 4 km area) indicates that ΔN errors are about 1 N unit, in agreement with in situ observations. Measurements from an instrumented tower on summer days show that the 1 h refractivity changes up to a height of 100 m remain well correlated with near-surface values. The analysis of refractivity as represented in the operational Met Office Unified Model at 1.5, 4 and 12 km grid lengths demonstrates that, as model resolution increases, the spatial scales of the refractivity structures improve. It is shown that the magnitude of refractivity changes is progressively underestimated at larger grid lengths during summer. However, the daily time series of 1 h refractivity changes reveal that, whereas the radar-derived values are very well correlated with the in situ observations, the high-resolution model runs have little skill in getting the right values of ΔN in the right place at the right time. This suggests that the assimilation of these radar refractivity observations could benefit forecasts of the initiation of convection
Detection of functional PTEN lipid phosphatase protein and enzyme activity in squamous cell carcinomas of the head andeck, despite loss of heterozygosity at this locus
The human tumour suppressor gene PTEN located at 10q23 is mutated in a variety of tumour types particularly metastatic cases and in the germline of some individuals with Cowdens cancer predisposition syndrome. We have assessed the status of PTEN and associated pathways in cell lines derived from 19 squamous cell carcinomas of the head and neck. Loss of heterozygosity is evident at, or close to the PTEN gene in 5 cases, however there were no mutations in the remaining alleles. Furthermore by Western analysis PTEN protein levels are normal in all of these SCC-HN tumours and cell lines. To assess the possibility that PTEN may be inactivated by another mechanism, we characterized lipid phosphatase levels and from a specific PIP3 biochemical assay it is clear that PTEN is functionally active in all 19 human SCCs. Our data strongly suggest the possibility that a tumour suppressor gene associated with development of SCC-HN, other than PTEN, is located in this chromosomal region. This gene does not appear to be MXI-1, which has been implicated in some other human tumour types. PTEN is an important negative regulator of PI3Kinase, of which subunit alpha is frequently amplified in SCC-HN. To examine the possibility that PI3K is upregulated by amplification in this tumour set we assessed the phosphorylation status of Akt, a downstream target of PI3K. In all cases there is no detectable increase in Akt phosphorylation. Therefore there is no detectable defect in the PI3K pathway in SCC-HN suggesting that the reason for 3q26.3 over-representation may be due to genes other than PI3K110α. © 2001 Cancer Research Campaign http://www.bjcancer.co
Benefits of undergraduate participation in faculty research in natural resources
Graduate student assistance with faculty research is common in university natural resource programs. Traditionally, undergraduate students are involved less with research programs of faculty. The Uintah Basin Branch Campus of Utah State University provides a unique setting for developing research projects in natural resources that involve undergraduates. We use a research project on the control of greasewood (Sarcobatus vermiculatus) iin the Book Cliffs, Utah to illustrate the benefits and challenges for undergraduate students and faculty of collaboration on research. Students benefit by interacting with faculty outside the classroom; by applying classroom learning to field problems; and by working with natural resource management personnel. Faculty benefit by observing the ability of students to apply classroom learning to field situations; by maintaining a scholarly research program; and by interacting with students outside the classroom
Predatory journals recruit fake editor
An investigation finds that dozens of academic titles offered ‘Dr Fraud’ — a sham, unqualified scientist — a place on their editorial board. Katarzyna Pisanski and colleagues report
Fragmentation and systematics of the Pygmy Dipole Resonance in the stable N=82 isotones
The low-lying electric dipole (E1) strength in the semi-magic nucleus 136Xe
has been measured which finalizes the systematic survey to investigate the
so-called pygmy dipole resonance (PDR) in all stable even N=82 isotones with
the method of nuclear resonance fluorescence using real photons in the entrance
channel. In all cases, a fragmented resonance-like structure of E1 strength is
observed in the energy region 5 MeV to 8 MeV. An analysis of the fragmentation
of the strength reveals that the degree of fragmentation decreases towards the
proton-deficient isotones while the total integrated strength increases
indicating a dependence of the total strength on the neutron-to-proton ratio.
The experimental results are compared to microscopic calculations within the
quasi-particle phonon model (QPM). The calculation includes complex
configurations of up to three phonons and is able to reproduce also the
fragmentation of the E1 strength which allows to draw conclusions on the
damping of the PDR. Calculations and experimental data are in good agreement in
the degree of fragmentation and also in the integrated strength if the
sensitivity limit of the experiments is taken into account
Photoactivation experiment on 197Au and its implications for the dipole strength in heavy nuclei
The 197Au(gamma,n) reaction is used as an activation standard for
photodisintegration studies on astrophysically relevant nuclei. At the
bremsstrahlung facility of the superconducting electron accelerator ELBE
(Electron Linear accelerator of high Brilliance and low Emittance) of
Forschungszentrum Dresden-Rossendorf, photoactivation measurements on 197Au
have been performed with bremsstrahlung endpoint energies from 8.0 to 15.5 MeV.
The measured activation yield is compared with previous experiments as well as
with calculations using Hauser-Feshbach statistical models. It is shown that
the experimental data are best described by a two-Lorentzian parametrization
with taking the axial deformation of 197Au into account. The experimental
197Au(gamma,n) reaction yield measured at ELBE via the photoactivation method
is found to be consistent with previous experimental data using photon
scattering or neutron detection methods.Comment: 9 page
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