2,124 research outputs found
Variation in Organic Standards Prior to the National Organic Program
Interest in establishing nationally uniform certification, labeling, and management standards for organic products grew out of concern that the existence of multiple standards led to consumer and supply chain confusion about, and lack of confidence in, these products. The National Organic Program Final Rule, issued in December 2000, is the result of this interest. We analyze the certification system that was in place prior to the new national rule to evaluate the extent of differences between certification standards and how the national rule is likely to impact the market for organic products. Our analysis suggests that most differences among US certification standards were minor. Also, the most important impacts of the national standard may be in facilitating trade in ingredients and products certified by different certifiers, increasing buyer confidence, and facilitating exports. However, the national rule may decrease the ability of organic certifiers and consumers to place differing emphasis on the multiple goals of organic production and may decrease the flexibility of organic standards to respond to changing market conditions, including new technologies.organic agriculture, organic certification standards, organic labeling, organic market, Agribusiness, Marketing,
Strategic Management and the Internal Organization of Food Marketing Firms
Agribusiness, Industrial Organization,
Restructuring's Effect on Related and Unrelated Diversification Among Top Food Manufacturing Firms in the 1980s
Corporate restructuring during the 1980s is argued to have focused on improving firm performance by increasing related and decreasing unrelated diversification. The restructuring patterns of top food manufacturing firms do not support this; instead, much of the restructuring appears to have been driven by the pursuit of stronger market positions. TheAgribusiness, Industrial Organization,
High Order QED Corrections in Physics of Positronium
High-order perturbative corrections to positronium decays and hyperfine
splitting are briefly reviewed. Theoretical predictions are compared to the
most recent experimental data. Perspectives of future calculations are
discussed.Comment: 8 pages, LaTeX, talk given at Workshop on Positronium Physics, ETH
Honggerberg, Zurich, May 30-31, 2003, a misprint in Eq. (1) correcte
Changing contribution of area-level deprivation to total variance in age at death: A population-based decomposition analysis
MAGMO: Coherent magnetic fields in the star forming regions of the Carina-Sagittarius spiral arm tangent
We present the pilot results of the `MAGMO' project, targeted observations of
ground-state hydroxyl masers towards sites of 6.7-GHz methanol maser emission
in the Carina-Sagittarius spiral arm tangent, Galactic longitudes 280 degrees
to 295 degrees. The `MAGMO' project aims to determine if Galactic magnetic
fields can be traced with Zeeman splitting of masers associated with star
formation. Pilot observations of 23 sites of methanol maser emission were made,
with the detection of ground-state hydroxyl masers towards 11 of these and six
additional offset sites. Of these 17 sites, nine are new detections of sites of
1665-MHz maser emission, three of them accompanied by 1667-MHz emission. More
than 70% of the maser features have significant circular polarization, whilst
only ~10% have significant linear polarization (although some features with up
to 100% linear polarization are found). We find 11 Zeeman pairs across six
sites of high-mass star formation with implied magnetic field strengths between
-1.5 mG and +3.8 mG and a median field strength of +1.6 mG. Our measurements of
Zeeman splitting imply that a coherent field orientation is experienced by the
maser sites across a distance of 5.3+/-2.0 kpc within the Carina-Sagittarius
spiral arm tangent.Comment: 19 pages, 13 figures, accepted for publication in MNRA
A quantum mechanical approach to establishing the magnetic field orientation from a maser Zeeman profile
Recent comparisons of magnetic field directions derived from maser Zeeman
splitting with those derived from continuum source rotation measures have
prompted new analysis of the propagation of the Zeeman split components, and
the inferred field orientation. In order to do this, we first review differing
electric field polarization conventions used in past studies. With these
clearly and consistently defined, we then show that for a given Zeeman
splitting spectrum, the magnetic field direction is fully determined and
predictable on theoretical grounds: when a magnetic field is oriented away from
the observer, the left-hand circular polarization is observed at higher
frequency and the right-hand polarization at lower frequency. This is
consistent with classical Lorentzian derivations. The consequent interpretation
of recent measurements then raises the possibility of a reversal between the
large-scale field (traced by rotation measures) and the small-scale field
(traced by maser Zeeman splitting).Comment: 10 pages, 5 Figures, accepted for publication in MNRA
High-velocity feature of the class I methanol maser in G309.38-0.13
The Australia Telescope Compact Array (ATCA) has been used to map class I
methanol masers at 36 and 44 GHz in G309.38-0.13. Maser spots are found at nine
locations in an area of 50''x30'', with both transitions reliably detected at
only two locations. The brightest spot is associated with shocked gas traced by
4.5 micron emission. The data allowed us to make a serendipitous discovery of a
high-velocity 36-GHz spectral feature, which is blue-shifted by about 30 km/s
from the peak velocity at this frequency, but spatially located close to
(within a few arcseconds of) the brightest maser spot. We interpret this as
indicating an outflow parallel to the line of sight. Such a high velocity
spread of maser features, which has not been previously reported in the class I
methanol masers associated with a single molecular cloud, suggests that the
outflow most likely interacts with a moving parcel of gas.Comment: 6 pages, 2 figures, accepted by MNRAS Letter
Three loop gauge beta-function for the most general single gauge-coupling theory
We calculate the three loop contribution to the beta-function of the gauge
coupling constant in a general, anomaly-free, renormalisable gauge field theory
involving a single gauge coupling using the background field method in the
MSbar scheme.Comment: 10 latex page
Intermittent maser flare around the high mass young stellar object G353.273+0.641 I: data & overview
We have performed VLBI and single-dish monitoring of 22 GHz HO maser
emission from the high mass young stellar object G353.273+0.641 with VERA (VLBI
Exploration of Radio Astrometry) and Tomakamai 11-m radio telescope. Two maser
flares have been detected, separated almost two years. Frequent VLBI monitoring
has revealed that these flare activities have been accompanied by structural
change of the prominent shock front traced by H2O maser alignments. We have
detected only blue-shifted emissions and all maser features have been
distributed within very small area of 200 200 au in spite of
wide velocity range (> 100 km s). The light curve shows notably
intermittent variation and suggests that the HO masers in G353.273+0.641
are excited by episodic radio jet. The time-scale of \sim2 yr and
characteristic velocity of \sim500 km s also support this
interpretation. Two isolated velocity components of C50 (-53 \pm 7 km s)
and C70 (-73 \pm 7 km s) have shown synchronised linear acceleration of
the flux weighted V_{\rmn{LSR}} values (\sim-5 km s yr) during
the flare phase. This can be converted to the lower-limit momentum rate of 1.1
\times 10 M_{\sun} km s yr. Maser properties are quite
similar to that of IRAS 20126+4104 especially. This corroborates the previous
suggestion that G353.273+0.641 is a candidate of high mass protostellar object.
The possible pole-on geometry of disc-jet system can be suitable for direct
imaging of the accretion disc in this case.Comment: 13 pages, 5 figures accepted for publication in MNRA
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