17,981 research outputs found
Seeing farmers' markets: Theoretical and media perspectives on new sites of exchange in New Zealand
In this paper we explore the extent to which a reciprocal relationship exists between contemporary theorisation about farmers' markets in geography and the rapidly expanding public discourse surrounding these sites of exchange in New Zealand. Activities branded as farmers' markets are seen widely as local phenomena of systemic significance for the understanding of evolving geographies of production, consumption and exchange. As something ānewā on the landscape, farmers' markets also attract attention in the media. An electronic database of significant print media contributions over the period 1995 to 2007 provides the empirical basis for an assessment of the extent to which theorisation and the public discourse address common themes. Our analysis indicates that, while the economic and social constructions in both the research literature and the media database share common themes, strong contrasts in ways of āseeingā farmers' markets are apparent. We note the predilection in the print media to present the nature and purpose of farmers' markets through the personal experiences and āstoriesā of participants. There is a tendency to focus on the appeal of markets to the consumers who form the readership base. The theorised alterity of the farmers' market, either in terms of production methods or motivations for consumption, is not reflected strongly in media reports, and this raises questions about āover-theorisationā in the academic literature. Our aim is to promote reflection in both the editorial offices of the media and in the academy by documenting the nature of these contrasting views
The Takagi problem on the disk and bidisk
We give a new proof on the disk that a Pick problem can be solved by a
rational function that is unimodular on the unit circle and for which the
number of poles inside the disk is no more than the number of non-positive
eigenvalues of the Pick matrix. We use this method to find rational solutions
to Pick problems on the bidisk
Substituent effects on the nitrogen-15 and carbon-13 shieldings of some N-arylguanidinium chlorides
The 13C and 15N chemical shifts of five N-arylguanidinium chlorides carrying polar substituents, ranging in character from 4-methoxy to 4-nitro groups, have been determined by NMR spectroscopy at the natural-abundance level of 13C and 15N in dimethyl sulfoxide solution. Comparison of the 13C shifts of these salts with those of monosubstituted benzenes shows that the guanidinium group induces an average downfield shift of -5.8 ppm of the resonance of the aryl carbon to which it is attached (C1), an average upfield shift of +4.2 ppm for C2 and C6, and a small upfield shift of +1.9 ppm for C4. The shifts of C3 and C5 are small and erratic relative to the corresponding carbons in monosubstituted benzenes. The 15N resonances of the guanidinium nitrogens are quite sensitive to electric effects resulting from substitution of polar groups at C4. The 15N shift of the ==NAr nitrogen relative to that of the salts suggests that the predominant tautomer for N-arylguanidines is (H2N)2C==NAr. The 15N shifts of the (NH2) 2 nitrogens correlate rather well with Ļp- parameters, whereas the shifts of the -NHAr nitrogens seem to correlate only with R values derived from the Ļp- substituent constants
AGRICULTURAL ECONOMICS STUDENTS AT SOUTHERN LAND GRANT UNIVERSITIES
Teaching/Communication/Extension/Profession,
Gas Bubbles Emerging from a Submerged Granular Bed
This fluid dynamics video was submitted to the Gallery of Fluid Motion for
the 2009 APS Division of Fluid Dynamics Meeting in Minneapolis, Minnesota. In
this video we show some results from a simple experiment where air was injected
by a single nozzle at known constant flow rates in the bottom of a granular bed
submerged in water. The injected air propagates through the granular bed in one
of two modes. Mode 1 emergence involves small discrete bubbles taking tortuous
paths through the interstitial space of the bed. Multiple small bubbles can be
emitted from the bed in an array of locations at the same time during Mode 1
emergence. Mode 2 emergence involves large discrete bubbles locally fluidizing
the granular bed and exiting the bed approximately above the injection site.
Bead diameter, bead density, and air flow rate were varied to investigate the
change in bubble release behavior at the top of the granular bed.
This system is a useful model for methane seeps in lakes. Methane bubbles are
released from the decomposition of organic matter in the lake bed. The initial
size of the bubble determines how much of the gas is absorbed into the lake and
how much of the gas reaches the surface and is released into the atmosphere.
The size and behavior of the emerging bubbles may also affect the amount of
vertical mixing occurring in the lake, as well as the mixing from the lake bed
into the benthic layer.Comment: 2009 APS DFD Gallery of Fluid Motion Submissio
- ā¦