1,141 research outputs found
Storage of frozen meats, poultry, eggs, fruits, and vegetables
Digitized 2007 AES.Includes bibliographical references (pages 42-43)
Visual preferences for grades of retail beef cuts : a study conducted in metropolitan St. Louis, 1954
This bulletin reports on Department of Agricultural Economics Research Project 96, 'Meat Preferences', Animal Husbandry Project 5, and Home Economics Project 109--P. [2].Digitized 2007 AES.Includes bibliographical references (page 67)
On the high energy proton spectrum measurements
The steepening of the proton spectrum beyond 1000 GeV and the rise in inelastic cross sections between 20 and 600 GeV observed by the PROTON-1-2-3 satellite experiments were explained by systematic effects of energy dependent albedo (backscatter) from the calorimeter
Exposure to an enriched CO 2 atmosphere alters carbon assimilation and allocation in a pine forest ecosystem
We linked a leaf-level CO 2 assimilation model with a model that accounts for light attenuation in the canopy and measurements of sap-flux-based canopy conductance into a new canopy conductance-constrained carbon assimilation (4C-A) model. We estimated canopy CO 2 uptake ( A nC ) at the Duke Forest free-air CO 2 enrichment (FACE) study. Rates of A nC estimated from the 4C-A model agreed well with leaf gas exchange measurements ( A net ) in both CO 2 treatments. Under ambient conditions, monthly sums of net CO 2 uptake by the canopy ( A nC ) were 13% higher than estimates based on eddy-covariance and chamber measurements. Annual estimates of A nC were only 3% higher than carbon (C) accumulations and losses estimated from ground-based measurements for the entire stand. The C budget for the Pinus taeda component was well constrained (within 1% of ground-based measurements). Although the closure of the C budget for the broadleaf species was poorer (within 20%), these species are a minor component of the forest. Under elevated CO 2 , the C used annually for growth, turnover, and respiration balanced only 80% of the A nC . Of the extra 700âg Câm â2 âa â1 (1999 and 2000 average), 86% is attributable to surface soil CO 2 efflux. This suggests that the production and turnover of fine roots was underestimated or that mycorrhizae and rhizodeposition became an increasingly important component of the C balance. Under elevated CO 2 , net ecosystem production increased by 272âg Câm â2 âa â1 : 44% greater than under ambient CO 2 . The majority (87%) of this C was sequestered in a moderately long-term C pool in wood, with the remainder in the forest floorâsoil subsystem.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73982/1/j.1365-2486.2003.00662.x.pd
Relationship Between Aerosol Optical Depth and Particulate Matter Over Singapore: Effects of Aerosol Vertical Distributions
As part of the Seven Southeast Asian Studies (7SEAS) program, an Aerosol Robotic Network (AERONET) sun photometer and a Micro-Pulse Lidar Network (MPLNET) instrument have been deployed at Singapore to study the regional aerosol environment of the Maritime Continent (MC). In addition, the Navy Aerosol Analysis and Prediction System (NAAPS) is used to model aerosol transport over the region. From 24 September 2009 to 31 March 2011, the relationships between ground-, satellite- and model-based aerosol optical depth (AOD) and particulate matter with aerodynamic equivalent diameters less than 2.5 microns (PM2.5) for air quality applications are investigated. When MPLNET-derived aerosol scale heights are applied to normalize AOD for comparison with surface PM2.5 data, the empirical relationships are shown to improve with an increased 11%, 10% and 5% in explained variances, for AERONET, MODIS and NAAPS respectively. The ratios of root mean square errors to standard deviations for the relationships also show corresponding improvements of 8%, 6% and 2%. Aerosol scale heights are observed to be bimodal with a mode below and another above the strongly-capped/deep near-surface layer (SCD; 0-1.35 km). Aerosol extinctions within the SCD layer are well-correlated with surface PM2.5 concentrations, possibly due to strong vertical mixing in the region
Increasing aridity will not offset CO fertilization in fast-growing eucalypts with access to deep soil water
Rising atmospheric [CO] (C) generally enhances tree growth if nutrients are not limiting. However, reduced water availability and elevated evaporative demand may offset such fertilization. Trees with access to deep soil water may be able to mitigate such stresses and respond more positively to C. Here, we sought to evaluate how increased vapor pressure deficit and reduced precipitation are likely to modify the impact of elevated C (eC) on tree productivity in an Australian Eucalyptus saligna Sm. plantation with access to deep soil water. We parameterized a forest growth simulation model (GOTILWA+) using data from two field experiments on E. saligna: a 2âyear wholeâtree chamber experiment with factorial C (ambient =380, elevated =620 ÎŒmol mol) and watering treatments, and a 10âyear standâscale irrigation experiment. Model evaluation showed that GOTILWA+ can capture the responses of canopy C uptake to (1) rising vapor pressure deficit (D) under both C treatments; (2) alterations in tree water uptake from shallow and deep soil layers during soil dryâdown; and (3) the impact of irrigation on tree growth. Simulations suggest that increasing C up to 700 ÎŒmol mol alone would result in a 33% increase in annual gross primary production (GPP) and a 62% increase in biomass over 10 years. However, a combined 48% increase in D and a 20% reduction in precipitation would halve these values. Our simulations identify high D conditions as a key limiting factor for GPP. They also suggest that rising Ca will compensate for increasing aridity limitations in E. saligna trees with access to deep soil water under nonânutrient limiting conditions, thereby reducing the negative impacts of global warming upon this eucalypt species. Simulation models not accounting for water sources available to deepârooting trees are likely to overestimate aridity impacts on forest productivity and C stocks
Physical and Optical Characteristics of the October 2010 Haze Event Over Singapore: A Photometric and Lidar Analysis
Trans-boundary biomass burning smoke episodes have increased dramatically during the past 20-30 years and have become an annual phenomenon in the SouthEastAsia region. On 15th October 2010, elevated levels of fire activity were detected by remote sensing satellites (e.g. MODIS). On the same date, measurements of fine particulate matter (PM2.5) at Singapore and Malaysia found high levels of fine mode particles in the local environment. All these observations were indicative of the initial onset of a smoke episode that lasted for several days. In this work, we investigate the temporal evolution of this smoke episode by analyzing the physical and optical properties of smoke particles with the aid of an AERONET Sun photometer, an MPLNet micropulse lidar, and surface PM2.5 measurements. Elevated levels of fire activity coupled with high aerosol optical depth and PM2.5 were observed over a period of nine days. Increased variability of parameters such as aerosol optical depth, Angstrom exponent number and its fine mode equivalents all indicated high levels of fine particulate presence in the atmosphere. Smoke particle growth due to aging, coagulation and condensation mechanisms was detected during the afternoons and over several days. Retrieved lidar ratios were compatible with the presence of fine particulate within the boundary/aerosol layer. Moreover, retrieved particle size distribution as well as single scattering albedo indicated the prevalence of the fine mode particulate regime as well as particles showing enhanced levels of absorption respectively
A Measurement of the Spatial Distribution of Diffuse TeV Gamma Ray Emission from the Galactic Plane with Milagro
Diffuse -ray emission produced by the interaction of cosmic-ray
particles with matter and radiation in the Galaxy can be used to probe the
distribution of cosmic rays and their sources in different regions of the
Galaxy. With its large field of view and long observation time, the Milagro
Gamma Ray Observatory is an ideal instrument for surveying large regions of the
Northern Hemisphere sky and for detecting diffuse -ray emission at very
high energies. Here, the spatial distribution and the flux of the diffuse
-ray emission in the TeV energy range with a median energy of 15 TeV
for Galactic longitudes between 30 and 110 and between
136 and 216 and for Galactic latitudes between -10 and
10 are determined. The measured fluxes are consistent with predictions
of the GALPROP model everywhere except for the Cygnus region
(). For the Cygnus region, the flux is twice the
predicted value. This excess can be explained by the presence of active cosmic
ray sources accelerating hadrons which interact with the local dense
interstellar medium and produce gamma rays through pion decay.Comment: 15 pages, 3 figures, accepted by Ap
The Intrinsic Origin of Spin Echoes in Dipolar Solids Generated by Strong Pi Pulses
In spectroscopy, it is conventional to treat pulses much stronger than the
linewidth as delta-functions. In NMR, this assumption leads to the prediction
that pi pulses do not refocus the dipolar coupling. However, NMR spin echo
measurements in dipolar solids defy these conventional expectations when more
than one pi pulse is used. Observed effects include a long tail in the CPMG
echo train for short delays between pi pulses, an even-odd asymmetry in the
echo amplitudes for long delays, an unusual fingerprint pattern for
intermediate delays, and a strong sensitivity to pi-pulse phase. Experiments
that set limits on possible extrinsic causes for the phenomena are reported. We
find that the action of the system's internal Hamiltonian during any real pulse
is sufficient to cause the effects. Exact numerical calculations, combined with
average Hamiltonian theory, identify novel terms that are sensitive to
parameters such as pulse phase, dipolar coupling, and system size.
Visualization of the entire density matrix shows a unique flow of quantum
coherence from non-observable to observable channels when applying repeated pi
pulses.Comment: 24 pages, 27 figures. Revised from helpful referee comments. Added
new Table IV, new paragraphs on pages 3 and 1
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