26,814 research outputs found
Urban environmental health applications of remote sensing
An urban area was studied through the use of the inventory-by-surrogate method rather than by direct interpretation of photographic imagery. Prior uses of remote sensing in urban and public research are examined. The effects of crowding, poor housing conditions, air pollution, and street conditions on public health are considered. Color infrared photography was used to categorize land use features and the grid method was used in photo interpretation analysis. The incidence of shigella and salmonella, hepatitis, meningitis, tuberculosis, myocardial infarction and veneral disease were studied, together with mortality and morbidity rates. Sample census data were randomly collected and validated. The hypothesis that land use and residential quality are associated with and act as an influence upon health and physical well-being was studied and confirmed
Urban environmental health applications of remote sensing, summary report
Health and its association with the physical environment was studied based on the hypothesis that there is a relationship between the man-made physical environment and health status of a population. The statistical technique of regression analysis was employed to show the degree of association and aspects of physical environment which accounted for the greater variation in health status. Mortality, venereal disease, tuberculosis, hepatitis, meningitis, shigella/salmonella, hypertension and cardiac arrest/myocardial infarction were examined. The statistical techniques were used to measure association and variation, not necessarily cause and effect. Conclusions drawn show that the association still exists in the decade of the 1970's and that it can be successfully monitored with the methodology of remote sensing
Combined production of broilers and fruits
Combined production of broilers and fruit trees is a subject often discussed in organic fruit
production in Denmark. Very little research has been carried out on this type of production
system. In organic production in Denmark, nearly no pesticides are allowed, so the need
for alternative pest control is large. Apple sawfly (Hoplocampa testudinea) and pear midge
(Contarinia pyrivora) cause big crop losses in apples and pears respectively, in unsprayed
organic fruit production. Both insects infest fruitlets and cause these to drop prematurely
after which the pests pupate in the topsoil. In the present experiment a research orchard
with the varieties ‘Discovery’ and ‘Conference’ were used as outdoor area for broilers to
minimise the population of sawflies and pear midges, and to reduce the need for weeding
and manuring. The trees were kept unsprayed. Fruit yield and fruit quality were assessed
at harvest. White sticky traps were placed in the test area in order to measure the
occurrence of sawfly over time. The infestation of pear midge was investigated counting
the infested fruitlets in clusters on trees at the centre of the plots. The catch of apple
sawflies was reduced in the combined apple and broiler production, but no significant
effect on the yield or the fruit quality was seen. Experiences from on-farm research show
that combining fruit and egg-production is one way to reduce the problem with apple
sawfly, but poultry alone is not a sufficient way of controlling sawflies. The welfare and
health of the broilers were excellent under fruit trees
Quantum phase-space analysis of the pendular cavity
We perform a quantum mechanical analysis of the pendular cavity, using the
positive-P representation, showing that the quantum state of the moving mirror,
a macroscopic object, has noticeable effects on the dynamics. This system has
previously been proposed as a candidate for the quantum-limited measurement of
small displacements of the mirror due to radiation pressure, for the production
of states with entanglement between the mirror and the field, and even for
superposition states of the mirror. However, when we treat the oscillating
mirror quantum mechanically, we find that it always oscillates, has no
stationary steady-state, and exhibits uncertainties in position and momentum
which are typically larger than the mean values. This means that previous
linearised fluctuation analyses which have been used to predict these highly
quantum states are of limited use. We find that the achievable accuracy in
measurement is far worse than the standard quantum limit due to thermal noise,
which, for typical experimental parameters, is overwhelming even at 2 mK.Comment: 25 pages, 6 figures To be published in Phys. Rev.
Measurement of the interaction strength in a Bose-Fermi mixture with 87Rb and 40K
A quantum degenerate, dilute gas mixture of bosonic and fermionic atoms was
produced using 87Rb and 40K. The onset of degeneracy was confirmed by observing
the spatial distribution of the gases after time-of-flight expansion. Further,
the magnitude of the interspecies scattering length between the doubly spin
polarized states of 87Rb and 40K, |a_RbK|, was determined from
cross-dimensional thermal relaxation. The uncertainty in this collision
measurement was greatly reduced by taking the ratio of interspecies and
intraspecies relaxation rates, yielding |a_RbK| = 250 +/- 30 a_0, which is a
lower value than what was reported in [M. Modugno et al., Phys. Rev. A 68,
043626 (2003)]. Using the value for |a_RbK| reported here, current T=0 theory
would predict a threshold for mechanical instability that is inconsistent with
the experimentally observed onset for sudden loss of fermions in [G. Modugno et
al., Science 297, 2240 (2002)].Comment: RevTeX4 + 4 eps figures; Replaced with published versio
Radio frequency interference survey over the 1.0-10.4 GHz frequency range at the Goldstone-Venus Development Station
The results of a low sensitivity Radio Frequency Interference (RFI) survey carried out at the Venus Station of the Goldstone Communications Complex are reported. The data cover the spectral range from 1 GHz to 10.4 GHz with a 10-kHz instantaneous bandwidth. Frequency and power levels were observed using a sweep-frequency spectrum analyzer connected to a 1-m diameter antenna pointed at zenith. The survey was conducted from February 16, 1987 through February 24, 1987
On a counterexample to a conjecture by Blackadar
Blackadar conjectured that if we have a split short-exact sequence 0 -> I ->
A -> A/I -> 0 where I is semiprojective and A/I is isomorphic to the complex
numbers, then A must be semiprojective. Eilers and Katsura have found a
counterexample to this conjecture. Presumably Blackadar asked that the
extension be split to make it more likely that semiprojectivity of I would
imply semiprojectivity of A. But oddly enough, in all the counterexamples of
Eilers and Katsura the quotient map from A to A/I is split. We will show how to
modify their examples to find a non-semiprojective C*-algebra B with a
semiprojective ideal J such that B/J is the complex numbers and the quotient
map does not split.Comment: 6 page
Observation of Heteronuclear Feshbach Resonances in a Bose-Fermi Mixture
Three magnetic-field induced heteronuclear Feshbach resonances were
identified in collisions between bosonic 87Rb and fermionic 40K atoms in their
absolute ground states. Strong inelastic loss from an optically trapped mixture
was observed at the resonance positions of 492, 512, and 543 +/- 2 G. The
magnetic-field locations of these resonances place a tight constraint on the
triplet and singlet cross-species scattering lengths, yielding -281 +/- 15 Bohr
and -54 +/- 12 Bohr, respectively. The width of the loss feature at 543 G is
3.7 +/- 1.5 G wide; this broad Feshbach resonance should enable experimental
control of the interspecies interactions.Comment: revtex4 + 5 EPS figure
vbyCaHbeta CCD Photometry of Clusters. VI. The Metal-Deficient Open Cluster NGC 2420
CCD photometry on the intermediate-band vbyCaHbeta system is presented for
the metal-deficient open cluster, NGC 2420. Restricting the data to probable
single members of the cluster using the CMD and the photometric indices alone
generates a sample of 106 stars at the cluster turnoff. The average E(b-y) =
0.03 +/- 0.003 (s.e.m.) or E(B-V) = 0.050 +/- 0.004 (s.e.m.), where the errors
refer to internal errors alone. With this reddening, [Fe/H] is derived from
both m1 and hk, using b-y and Hbeta as the temperature index. The agreement
among the four approaches is reasonable, leading to a final weighted average of
[Fe/H] = -0.37 +/- 0.05 (s.e.m.) for the cluster, on a scale where the Hyades
has [Fe/H] = +0.12. When combined with the abundances from DDO photometry and
from recalibrated low-resolution spectroscopy, the mean metallicity becomes
[Fe/H] = -0.32 +/- 0.03. It is also demonstrated that the average cluster
abundances based upon either DDO data or low-resolution spectroscopy are
consistently reliable to 0.05 dex or better, contrary to published attempts to
establish an open cluster metallicity scale using simplistic offset corrections
among different surveys.Comment: scheduled for Jan. 2006 AJ; 33 pages, latex, includes 7 figures and 2
table
Quantum field effects in coupled atomic and molecular Bose-Einstein condensates
This paper examines the parameter regimes in which coupled atomic and
molecular Bose-Einstein condensates do not obey the Gross-Pitaevskii equation.
Stochastic field equations for coupled atomic and molecular condensates are
derived using the functional positive-P representation. These equations
describe the full quantum state of the coupled condensates and include the
commonly used Gross-Pitaevskii equation as the noiseless limit. The model
includes all interactions between the particles, background gas losses,
two-body losses and the numerical simulations are performed in three
dimensions. It is found that it is possible to differentiate the quantum and
semiclassical behaviour when the particle density is sufficiently low and the
coupling is sufficiently strong.Comment: 4 postscript figure
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