14,090 research outputs found
Polarimetric Evidence of Non-Spherical Winds
Polarization observations yield otherwise unobtainable information about the
geometrical structure of unresolved objects. In this talk we review the
evidences for non-spherically symmetric structures around Luminous Hot Stars
from polarimetry and what we can learn with this technique. Polarimetry has
added a new dimension to the study of the envelopes of Luminous Blue Variables,
Wolf-Rayet stars and B[e] stars, all of which are discussed in some detail.Comment: 8 pages, 2 encapsulated Postscript figures, uses lamuphys.sty.
Invited review to appear in IAU Coll. 169, Variable and Non-Spherical Stellar
Winds in Luminous Hot Stars, eds. B. Wolf, A.Fullerton and O. Stahl
(Springer
Scalable Parallel Numerical Constraint Solver Using Global Load Balancing
We present a scalable parallel solver for numerical constraint satisfaction
problems (NCSPs). Our parallelization scheme consists of homogeneous worker
solvers, each of which runs on an available core and communicates with others
via the global load balancing (GLB) method. The parallel solver is implemented
with X10 that provides an implementation of GLB as a library. In experiments,
several NCSPs from the literature were solved and attained up to 516-fold
speedup using 600 cores of the TSUBAME2.5 supercomputer.Comment: To be presented at X10'15 Worksho
Effects of Dietary Fat Source on Performance of Lactating Dairy Cows Fed a Pre-mixed Concentrate
Inclusion of a pre-blended concentrate (OneTrak®, Cargill Inc., Blair, NE) in the total mixed ration (TMR) for dairy cows can simplify the daily mixing of dietary ingredients. A cow’s response to fat supplementation can be affected by other dietary ingredients; however, little is known about production responses to dietary fat in diets with high concentrations of non-forage fiber. This study evaluated cow performance in response to fat sources when the ration contained a pre-blended concentrate composed largely of a non-forage fiber source. Six pens of mid-lactation cows were studied; the addition of saturated fat (Energy Booster 100) and rumen-protected unsaturated fat (Megalac) were compared to a control diet with no added fat. Milk yield tended to increase with both fat sources. Protein concentration decreased with fat supplementation but protein yield did not differ. Efficiency of conversion of feed to milk tended to increase for Megalac compared with Energy Booster. These responses to dietary fat are comparable to those for diets without OneTrak®, suggesting that no unusual dietary interactions with fat supplements are apparent with OneTrak® feeding programs
Linking Resilience Theory and Diffusion of Innovations Theory to Understand the Potential for Perennials in the U.S. Corn Belt
In the last 200 yr, more than 80% of the land in the U.S. Corn Belt agro-ecosystem has been converted from natural perennial vegetation to intensive agricultural production of row crops. Despite research showing how re-integration of perennial vegetation, e.g., cover crops, pasture, riparian buffers, and restored wetlands, at strategic landscape positions can bolster declining regional ecosystem functions, the amount of land area devoted to row crop production in the Corn Belt continues to increase. As this region enters a time of fast-paced and uncertain reorganization driven by the emerging bioeconomy, changes in land use will continue to take place that will impact the resilience of the Corn Belt’s linked social and ecological systems for years to come. Both resilience theory and the diffusion of innovations theory investigate how change is brought about in systems through the adaptation and innovation of social actors. In this paper, we integrate these two frameworks in the analysis of 33 in-depth interviews to improve our understanding of how rural Corn Belt stakeholders make conservation decisions in the midst of an uncertain future. Interview data indicate that the adoption of conservation practices is based not only on immediate profitability but also on the interplay between contextual factors at three distinct levels of the system: compatibility with farm priorities, profitability, practices, and technologies; community-level reinforcement through local social networks, norms, and support structures; and consistent, straightforward, flexible, and well-targeted incentives and regulations issuing from regional institutions. Interviewees suggest that the multiscale drivers that currently support the continued expansion of row crop production could be realigned with conservation objectives in landscapes of the future. Adaptation of social actors through collaborative learning at the community level may be instrumental in brokering the sort of multiscale system change that would lead to more widespread adoption of perennial cover types in the Corn Belt
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