4,311 research outputs found
The Evolving Agricultural Marketplace: Selected Results and Implications for the West from the Laboratory
Marketing,
Tracing the Conversion of Gas into Stars in Young Massive Cluster Progenitors
Whilst young massive clusters (YMCs; 10 M, age
100 Myr) have been identified in significant numbers, their
progenitor gas clouds have eluded detection. Recently, four extreme molecular
clouds residing within 200 pc of the Galactic centre have been identified as
having the properties thought necessary to form YMCs. Here we utilise far-IR
continuum data from the Herschel Infrared Galactic Plane Survey (HiGAL) and
millimetre spectral line data from the Millimetre Astronomy Legacy Team 90 GHz
Survey (MALT90) to determine their global physical and kinematic structure. We
derive their masses, dust temperatures and radii and use virial analysis to
conclude that they are all likely gravitationally bound -- confirming that they
are likely YMC progenitors. We then compare the density profiles of these
clouds to those of the gas and stellar components of the Sagittarius B2 Main
and North proto-clusters and the stellar distribution of the Arches YMC. We
find that even in these clouds -- the most massive and dense quiescent clouds
in the Galaxy -- the gas is not compact enough to form an Arches-like ( =
2x10 M, R = 0.4 pc) stellar distribution. Further
dynamical processes would be required to condense the resultant population,
indicating that the mass becomes more centrally concentrated as the
(proto)-cluster evolves. These results suggest that YMC formation may proceed
hierarchically rather than through monolithic collapse.Comment: 12 pages, 8 figures, 1 table. Accepted by MNRA
Out With the Old, In With the New: Are Western Commodity Producers Ready for Buyouts?
Agricultural and Food Policy,
SUPPLY AND DEMAND RISKS IN LABORATORY FORWARD AND SPOT MARKETS: IMPLICATIONS FOR AGRICULTURE
Laboratory experimental methods are used to investigate the impacts of supply and/or demand risks on prices, quantities traded, and earnings within forward and spot market institutions. Random demand and/or supply shifts can be as much as 25 percent of the expected equilibrium outcome. Nevertheless, results suggest that the spot or forward trading institution itself has a greater influence on market outcomes than the presence of risk within the trading institutions. Sellers tend to have relatively higher earnings in a spot market than buyers, regardless of the risk. Total surplus, however, generally is greater in a forward market.laboratory markets, forward market, spot market, supply and/or demand risks, Demand and Price Analysis, Marketing,
SUPPLY AND DEMAND RISKS IN FORWARD AND SPOT MARKETS: IMPLICATIONS FOR AGRICULTURE
Laboratory methods are used to investigate the impacts of supply and/or demand risks on prices, quantities traded, and earnings within forward and spot market institutions. Results suggest that the spot or forward trading institution itself has a greater influence on market outcomes than supply/demand risks within the institution.Marketing,
A First Comparison of Millimeter Continuum and Mg II Ultraviolet Line Emission from the Solar Chromosphere
We present joint observations of the Sun by the Atacama Large
Millimeter/submillimeter Array (ALMA) and the Interface Region Imaging
Spectrograph (IRIS). The observations were made of a solar active region on
2015 December 18 as part of the ALMA science verification effort. A map of the
Sun's continuum emission of size was obtained by ALMA at a
wavelength of 1.25 mm (239 GHz) using mosaicing techniques. A contemporaneous
map of size was obtained in the Mg II h doublet line at
2803.5\AA\ by IRIS. Both mm/submm continuum emission and ultraviolet
(UV) line emission are believed to originate from the solar chromosphere and
both have the potential to serve as powerful and complementary diagnostics of
physical conditions in this poorly understood layer of the solar atmosphere.
While a clear correlation between mm- brightness temperature and
the Mg II h line radiation temperature is observed the slope is ,
perhaps as a result of the fact that these diagnostics are sensitive to
different parts of the chromosphere and/or the Mg II h line source function
includes a scattering component. There is a significant offset between the mean
(1.25 mm) and mean (Mg II), the former being
greater than the latter. Partitioning the maps into "sunspot", "quiet regions",
and "plage regions" we find that the slope of the scatter plots between the
IRIS Mg II h line and the ALMA brightness temperature is 0.4
(sunspot), 0.56 (quiet regions), and 0.66 (plage regions). We suggest that this
change may be caused by the regional dependence of the formation heights of the
IRIS and ALMA diagnostics, and/or the increased degree of coupling between the
UV source function and the local gas temperature in the hotter, denser gas in
plage regions.Comment: 8 pages, 2 figure
Is Agricultural Policy Decoupling against Human Nature? Experimental Evidence of Fairness Expectations’ Contributions to Payment Incidence
The objective of this research is to measure individuals’ fairness expectations and relate them to their market behavior in a private-negotiation institution. By doing this, we may inform model parameterization of field data and increase understanding of payment incidence causation. We hypothesize agents will change both their market and UG behavior when the tenant/proposer receives a subsidy following a successful negotiation. We also hypothesize that agents’ market behavior does relate to their fairness expectations in the UG. Two economic experiments were developed to test our hypotheses, a market and an ultimatum bargaining game experiment. We recruited 106 undergraduate students and conducted the experiments in an experimental laboratory using a computer based market mechanism. Our findings suggest fairness expectations need to be considered as a possible constraint on agents’ profit maximization behavior in land markets. The experimental evidence indicates market sellers or landlords demand higher land rental prices when tenants receive per-unit subsidies. Their ability to obtain a higher price appears to be more formidable in markets with limited matching opportunities. We conclude fairness expectations may constrain individuals’ profit-maximization behavior in the land market and, in turn, affect payment incidence in this market.Agricultural and Food Policy,
Revealing a Ring-like Cluster Complex in a Tidal Tail of the Starburst Galaxy NGC 2146
We report the discovery of a ring-like cluster complex in the starburst
galaxy NGC 2146. The Ruby Ring, so named due to its appearance, shows a clear
ring-like distribution of star clusters around a central object. It is located
in one of the tidal streams which surround the galaxy. NGC 2146 is part of the
Snapshot Hubble U-band Cluster Survey (SHUCS). The WFC3/F336W data has added
critical information to the available archival Hubble Space Telescope imaging
set of NGC 2146, allowing us to determine ages, masses, and extinctions of the
clusters in the Ruby Ring. These properties have then been used to investigate
the formation of this extraordinary system. We find evidence of a spatial and
temporal correlation between the central cluster and the clusters in the ring.
The latter are about 4 Myr younger than the central cluster, which has an age
of 7 Myr. This result is supported by the H alpha emission which is strongly
coincident with the ring, and weaker at the position of the central cluster.
From the derived total H alpha luminosity of the system we constrain the star
formation rate density to be quite high, e.g. ~ 0.47 Msun/yr/kpc^2. The Ruby
Ring is the product of an intense and localised burst of star formation,
similar to the extended cluster complexes observed in M51 and the Antennae, but
more impressive because is quite isolated. The central cluster contains only 5
% of the total stellar mass in the clusters that are determined within the
complex. The ring-like morphology, the age spread, and the mass ratio support a
triggering formation scenario for this complex. We discuss the formation of the
Ruby Ring in a "collect & collapse" framework. The predictions made by this
model agree quite well with the estimated bubble radius and expansion velocity
produced by the feedback from the central cluster, making the Ruby Ring an
interesting case of triggered star formation.Comment: 11 pages, 7 figures, 1 table; Accepted for publication in MNRA
Gemini Spectroscopy and HST Imaging of the Stellar Cluster Population in Region B of M82
We present new spectroscopic observations of the stellar cluster population
of region B in the prototype starburst galaxy M82 obtained with the Gillett
Gemini-North 8.1-metre telescope. By coupling the spectroscopy with UBVI
photometry acquired with the Advanced Camera for Surveys (ACS) on the Hubble
Space Telescope (HST), we derive ages, extinctions and radial velocities for
seven young massive clusters (YMCs) in region B. We find the clusters to have
ages between 70 and 200 Myr and velocities in the range 230 to 350 km/s, while
extinctions Av vary between ~1-2.5 mag. We also find evidence of differential
extinction across the faces of some clusters which hinders the photometric
determination of ages and extinctions in these cases. The cluster radial
velocities indicate that the clusters are located at different depths within
the disk, and are on regular disk orbits. Our results overall contradict the
findings of previous studies, where region B was thought to be a bound region
populated by intermediate-age clusters that formed in an independent, offset
starburst episode that commenced 600 Myr-1 Gyr ago. Our findings instead
suggest that region B is optically bright because of low extinction patches,
and this allows us to view the cluster population of the inner M82 disk, which
probably formed as a result of the last encounter with M81. This study forms
part of a series of papers aimed at studying the cluster population of M82
using deep optical spectroscopy and multi-band photometry.Comment: 12 pages, 8 figures; accepted for publication in The Astrophysical
Journa
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