4,412 research outputs found
A New Approach to Climate Change: A Consideration of Ancillary Benefits in Linking Regional Permit Trading Systems
In this paper, I investigate the economic efficiency of two major approaches to greenhouse gas reduction, and evaluate their respective benefits. First, I trace the path of action and thinking on addressing climate change from a global to a regional level. Second, I consider the major economic benefits of having a globally-integrated greenhouse gas abatement system. Third, I consider the economic benefits of regional approaches to climate change, with a focus on the ancillary benefits from greenhouse gas abatement. I conclude by reviewing the challenges to linking regional abatement systems into a cohesive network, and suggest a potential future approach to an economically-efficient abatement of greenhouse gas emissions
Causes and Implications of the Food Price Surge
This paper analyzes the food price surge of 2005 to 2008 in order to better understand the factors causing higher and more volatile food prices during this period, to ascertain the relative importance and possible persistence of the different factors, and to suggest possible implications for future market behavior and policy reactions.Agricultural and Food Policy,
Interpretation of Long-term Trade Projections: China's Role in Forecast Discrepancies and its Impact on Expectations for World Agricultural Trade
Agricultural and Food Policy, International Relations/Trade,
Interpretation of Long-term Trade Projections: China's Role in Forecast Discrepancies and its Impact on Expectations for World Agricultural Trade
This report looks at the impact of China's grain projections on a global commodity baseline through a discussion of the 1998 FAPRI China corn outlook
Star formation in W3 - AFGL333: Young stellar content, properties and roles of external feedback
One of the key questions in the field of star formation is the role of
stellar feedback on subsequent star formation process. The W3 giant molecular
cloud complex at the western border of the W4 super bubble is thought to be
influenced by the stellar winds of the massive stars in W4. AFGL333 is a ~10^4
Msun cloud within W3. This paper presents a study of the star formation
activity within AFGL333 using deep JHKs photometry obtained from the NOAO
Extremely Wide-Field Infrared Imager combined with Spitzer-IRAC-MIPS
photometry. Based on the infrared excess, we identify 812 candidate young
stellar objects in the complex, of which 99 are classified as Class I and 713
are classified as Class II sources. The stellar density analysis of young
stellar objects reveals three major stellar aggregates within AFGL333, named
here AFGL333-main, AFGL333-NW1 and AFGL333-NW2. The disk fraction within
AFGL333 is estimated to be ~50-60%. We use the extinction map made from the
H-Ks colors of the background stars to understand the cloud structure and to
estimate the cloud mass. The CO-derived extinction map corroborates the cloud
structure and mass estimates from NIR color method. From the stellar mass and
cloud mass associated with AFGL333, we infer that the region is currently
forming stars with an efficiency of ~4.5% and at a rate of ~2 - 3 Msun
Myr-1pc-2. In general, the star formation activity within AFGL333 is comparable
to that of nearby low mass star-forming regions. We do not find any strong
evidence to suggest that the stellar feedback from the massive stars of nearby
W4 super bubble has affected the global star formation properties of the
AFGL333 region.Comment: 17 pages, 9 figures, Accepted for publication in Ap
Briefing Paper on the Demand for U.S. Commodity Exports and the Mississippi River: Past and Future
As part of the decision in evaluating the lock and dam upgrade on the Mississippi River, the U.S. Army Corps of Engineers (Corps) has contracted with various agricultural forecasting companies (most recently Sparks Companies, Inc.) to produce long range projections of agricultural exports and the implied demand for Mississippi River transportation services. The future demand for barge transportation services is a key component in evaluating the value of lock and dam upgrades. In this context, it is important to understand the volume of U.S. exports that utilize the river versus other modes of transportation
A disrupted circumstellar torus inside eta Carinae's Homunculus Nebula
We present thermal infrared images of the bipolar nebula surrounding eta
Carinae at six wavelengths from 4.8 to 24.5 microns. These were obtained with
the MIRAC3 camera system at the Magellan Observatory. Our images reveal new
intricate structure in the bright core of the nebula, allowing us to
re-evaluate interpretations of morphology seen in images with lower resolution.
Complex structures in the core might not arise from a pair of overlapping rings
or a cool (110 K) and very massive dust torus, as has been suggested recently.
Instead, it seems more likely that the arcs and compact knots comprise a warm
(350 K) disrupted torus at the intersection of the larger polar lobes. Some of
the arcs appear to break out of the inner core region, and may be associated
with equatorial features seen in optical images. The torus could have been
disrupted by a post-eruption stellar wind, or by ejecta from the Great Eruption
itself if the torus existed before that event. Kinematic data are required to
rule out either possibility.Comment: 8 pages, 3 figures (Fig. 1 in color); to appear in ApJ Letter
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