9,729 research outputs found
Farm Animal Welfare and Quality Verification
Existing empirical evidence suggests that farm animal welfare may not be a top-of-mind issue for many consumers in North America. Nevertheless, there is pressure from animal welfare groups on food retailers and processors to implement more stringent requirements for their suppliers. Is the demand for more stringent animal welfare protocols primarily determined by a subset of consumers with very strong preferences or by an underlying change in consumer and societal preferences? Who do consumers trust for credible quality assurances with respect to farm animal welfare attributes? This paper provides a basis for further analysis of these issues. The roles of different stakeholders in delivering farm animal welfare quality assurances to consumers are first discussed. Then a social welfare analysis of the Canadian market for animal friendly pork is presented under different scenarios with respect to the strength of consumer preferences and the existence of voluntary standards versus mandatory standards. The analysis suggests that a situation of voluntary labelling that is reasonably credible is desirable as it maximizes the welfare that accrues to all players on the market. Furthermore, this scenario allows heterogeneous consumers to choose between different combinations of price and quality according to their preferences. The paper concludes with suggestions for further research.farm animal welfare, quality assurance, labelling, certification, heterogeneous consumers., Agribusiness, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Q13, Q18,
The interstellar D1 line at high resolution
Observations at a resolving power or a velocity resolution are reported of the interstellar D(sub 1) line of Na I in the spectra of gamma Cas, delta Ori, epsilon Ori, pi Sco, delta Cyg, and alpha Cyg. An echelle grating was used in a double-pass configuration with a CCD detector in the coude spectrograph of the 2.7 m reflector at McDonald Observatory. At least 42 kinematically distinct clouds are detected along the light paths to the five more distant stars, in addition to a single cloud seen toward delta Cyg. The absorption lines arising in 13 of the clouds are sufficiently narrow and unblended to reveal clearly resolved hyperfine structure components split by 1.05 km/s. An additional 13 clouds apparently show comparably narrow, but more strongly blended, lines. For each individual cloud, upper limits T(sub max) and (v sub t)(sub max) on the temperature and the turbulent velocity, respectively, are derived by fitting the observed lines with theoretical absorption profiles
Report of the Higgs Working Group of the Tevatron Run 2 SUSY/Higgs Workshop
This report presents the theoretical analysis relevant for Higgs physics at
the upgraded Tevatron collider and documents the Higgs Working Group
simulations to estimate the discovery reach in Run 2 for the Standard Model and
MSSM Higgs bosons. Based on a simple detector simulation, we have determined
the integrated luminosity necessary to discover the SM Higgs in the mass range
100-190 GeV. The first phase of the Run 2 Higgs search, with a total integrated
luminosity of 2 fb-1 per detector, will provide a 95% CL exclusion sensitivity
comparable to that expected at the end of the LEP2 run. With 10 fb-1 per
detector, this exclusion will extend up to Higgs masses of 180 GeV, and a
tantalizing 3 sigma effect will be visible if the Higgs mass lies below 125
GeV. With 25 fb-1 of integrated luminosity per detector, evidence for SM Higgs
production at the 3 sigma level is possible for Higgs masses up to 180 GeV.
However, the discovery reach is much less impressive for achieving a 5 sigma
Higgs boson signal. Even with 30 fb-1 per detector, only Higgs bosons with
masses up to about 130 GeV can be detected with 5 sigma significance. These
results can also be re-interpreted in the MSSM framework and yield the required
luminosities to discover at least one Higgs boson of the MSSM Higgs sector.
With 5-10 fb-1 of data per detector, it will be possible to exclude at 95% CL
nearly the entire MSSM Higgs parameter space, whereas 20-30 fb-1 is required to
obtain a 5 sigma Higgs discovery over a significant portion of the parameter
space. Moreover, in one interesting region of the MSSM parameter space (at
large tan(beta)), the associated production of a Higgs boson and a b b-bar pair
is significantly enhanced and provides potential for discovering a non-SM-like
Higgs boson in Run 2.Comment: 185 pages, 124 figures, 55 table
Cohesion of BaReH and BaMnH: Density Functional Calculations and Prediction of (MnH Salts
Density functional calculations are used to calculate the structural and
electronic properties of BaReH and to analyze the bonding in this compound.
The high coordination in BaReH is due to bonding between Re 5 states and
states of -like symmetry formed from combinations of H orbitals in the
H cage. This explains the structure of the material, its short bond lengths
and other physical properties, such as the high band gap. We compare with
results for hypothetical BaMnH, which we find to have similar bonding and
cohesion to the Re compound. This suggests that it may be possible to
synthesize (MnH salts. Depending on the particular cation, such salts
may have exceptionally high hydrogen contents, in excess of 10 weight
Rotor redesign for a highly loaded 1800 ft/sec tip speed fan. 3: Laser Doppler velocimeter report
Laser Doppler velocimeter (LDV) techniques were employed for testing a highly loaded, 550 m/sec (1800 ft/sec) tip speed, test fan stage, the objective to provide detailed mapping of the upstream, intrablade, and downstream flowfields of the rotor. Intrablade LDV measurements of velocity and flow angle were obtained along four streamlines passing through the leading edge at 45%, 69%, 85%, and 95% span measured from hub to tip, at 100% of design speed, peak efficiency; 100% speed, near surge; and 95% speed, peak efficiency. At the design point, most passages appeared to have a strong leading edge shock, which moved forward with increasing strength near surge and at part speeds. The flow behind the shock was of a complex mixed subsonic and supersonic form. The intrablade flowfields were found to be significantly nonperiodic at 100% design speed, peak efficiency
Detecting Pulsars with Interstellar Scintillation in Variance Images
Pulsars are the only cosmic radio sources known to be sufficiently compact to
show diffractive interstellar scintillations. Images of the variance of radio
signals in both time and frequency can be used to detect pulsars in large-scale
continuum surveys using the next generation of synthesis radio telescopes. This
technique allows a search over the full field of view while avoiding the need
for expensive pixel-by-pixel high time resolution searches. We investigate the
sensitivity of detecting pulsars in variance images. We show that variance
images are most sensitive to pulsars whose scintillation time-scales and
bandwidths are close to the subintegration time and channel bandwidth.
Therefore, in order to maximise the detection of pulsars for a given radio
continuum survey, it is essential to retain a high time and frequency
resolution, allowing us to make variance images sensitive to pulsars with
different scintillation properties. We demonstrate the technique with
Murchision Widefield Array data and show that variance images can indeed lead
to the detection of pulsars by distinguishing them from other radio sources.Comment: 8 papes, 9 figures, accepted for publication in MNRA
A Parallel-Plate Electrochemical Reactor Model for the Destruction of Nitrate and Nitrite in Alkaline Waste Solutions
A parallel-plate electrochemical reactor model with multiple reactions at both electrodes and anolyte and catholyte recirculation tanks was modeled for the electrochemical destruction of nitrate and nitrite species in an alkaline solution. The model can be used to predict electrochemical reaction current efficiencies and outlet concentrations of species from the reactor, given inlet feed conditions and cell operating conditions. Also, predictions are made for off-gas composition and liquid-phase composition in the recirculation tanks. The results of case studies at different applied potentials are shown here. At lower applied potentials, the model predictions show that the destruction process is more energy efficient, but the time required to destroy a given amount of waste is increased
Magnetically-controlled velocity selection in a cold atom sample using stimulated Raman transitions
We observe velocity-selective two-photon resonances in a cold atom cloud in
the presence of a magnetic field. We use these resonances to demonstrate a
simple magnetometer with sub-mG resolution. The technique is particularly
useful for zeroing the magnetic field and does not require any additional laser
frequencies than are already used for standard magneto-optical traps. We verify
the effects using Faraday rotation spectroscopy.Comment: 5 pages, 6 figure
A Bayesian parameter estimation approach to pulsar time-of-arrival analysis
The increasing sensitivities of pulsar timing arrays to ultra-low frequency
(nHz) gravitational waves promises to achieve direct gravitational wave
detection within the next 5-10 years. While there are many parallel efforts
being made in the improvement of telescope sensitivity, the detection of stable
millisecond pulsars and the improvement of the timing software, there are
reasons to believe that the methods used to accurately determine the
time-of-arrival (TOA) of pulses from radio pulsars can be improved upon. More
specifically, the determination of the uncertainties on these TOAs, which
strongly affect the ability to detect GWs through pulsar timing, may be
unreliable. We propose two Bayesian methods for the generation of pulsar TOAs
starting from pulsar "search-mode" data and pre-folded data. These methods are
applied to simulated toy-model examples and in this initial work we focus on
the issue of uncertainties in the folding period. The final results of our
analysis are expressed in the form of posterior probability distributions on
the signal parameters (including the TOA) from a single observation.Comment: 16 pages, 4 figure
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