12,474 research outputs found
Integrated water resource systems: Theory and policy implications.
Water resource management / Water policy / Irrigation efficiency / Water demand / Leaching / Water use efficiency / Water supply / Evapotranspiration / Models / Water conservation
Investigating the role that the Southern Ocean biological pump plays in determining global ocean oxygen concentrations and deoxygenation
Global ocean circulation connects marine biogeochemical cycles through the long-range transport of nutrients and oxygen with the Southern Ocean (SO) acting as a water mass crossroads. The biological pump in the SO has been shown to play an important role in these dynamics and the amount of export production is known to have a large impact on remote deep ocean nutrients and dissolved inorganic carbon. However, the role that the SO biological pump plays in determining ocean oxygen concentrations is less well understood. In this study we investigate these dynamics by shutting off the SO biological pump in three different general ocean circulation models, each of which is coupled to a different prognostic biogeochemical model. Our results indicate that the present day SO biological pump is responsible for reducing oxygen levels in the deep ocean by up 70 mmol m-3. The SO biological pump also removes nutrients that would otherwise be used to fuel productivity and subsequently reduce oxygen in mid- to low-latitude sub-surface waters (i.e., without the SO biological pump, oxygen is lower in these regions due to higher productivity). Since SO productivity and export is expected to change in response to climate change we also examine the role that these changes may play in future ocean deoxygenation
UoS: a graph-based system for graded word sense induction
This paper presents UoS, a graph-based Word Sense Induction system which attempts to find all applicable senses of a target word given its context, grading each sense according to its suitability to the context. Senses of a target word are induced through use of a non-parameterised, linear-time clustering algorithm that returns maximal quasi-strongly connected components of a target word graph in which vertex pairs are assigned to the same cluster if either vertex has the highest edge weight to the other. UoS participated in SemEval-2013 Task 13: Word Sense Induction for Graded and Non-Graded Senses. Two system were submitted; both systems returned results comparable with those of the best performing systems
A Tractable Extension of Linear Indexed Grammars
It has been shown that Linear Indexed Grammars can be processed in polynomial
time by exploiting constraints which make possible the extensive use of
structure-sharing. This paper describes a formalism that is more powerful than
Linear Indexed Grammar, but which can also be processed in polynomial time
using similar techniques. The formalism, which we refer to as Partially Linear
PATR manipulates feature structures rather than stacks.Comment: 8 pages LaTeX, uses eaclap.sty, to appear in EACL-9
The origin of amorphous rims on lunar plagioclase grains: Solar wind damage or vapor condensates
A distinctive feature of micron sized plagioclase grains from mature lunar soils is a thin (20 to 100 nm) amorphous rim surrounding the grains. These rims were originally described from high voltage electron microscope observations of lunar plagioclase grains by Dran et al., who observed rims up to 100 nm thick on plagioclase grains from Apollo 11 and 12 soils. These rims are believed to be the product of solar wind damage. The amorphous rims were studied on micron sized plagioclase grains from a mature Apollo 16 soil using a JEOL 200FX transmission electron microscope equipped with an energy dispersive x ray spectrometer. It was found that the amorphous rims are compositionally distinct from the interior plagioclase and it is proposed that a major component of vapor condensates is present in the rims
Improving Access to Health Through Collaboration: Lessons Learned from The Colorado Trust's Partnerships for Health Initiative Evaluation
This report presents findings from the evaluation of four Partnerships in Health Initiative grantees that were addressing access to health in their communities through the formation of collaboratives. Outcomes achieved by the grantees as well as lessons learned for others embarking on collaborative processes are described
Springer theory via the Hitchin fibration
In this paper, we translate the Springer theory of Weyl group representations
into the language of symplectic topology. Given a semisimple complex group G,
we describe a Lagrangian brane in the cotangent bundle of the adjoint quotient
g/G that produces the perverse sheaves of Springer theory. The main technical
tool is an analysis of the Fourier transform for constructible sheaves from the
perspective of the Fukaya category. Our results can be viewed as a toy model of
the quantization of Hitchin fibers in the Geometric Langlands program.Comment: 37 pages; to appear in Compos. Mat
Global laminate optimization on geometrically partitioned shell structures
A method aimed at the optimization of locally varying laminates is investigated. The structure is partitioned into geometrical sections. These sections are covered by global plies. A variable-length representation scheme for an evolutionary algorithm is developed. This scheme encodes the number of global plies, their thickness, material, and orientation. A set of genetic variation operators tailored to this particular representation is introduced. Sensitivity information assists the genetic search in the placement of reinforcements and optimization of ply angles. The method is investigated on two benchmark applications. There it is able to find significant improvements. A case study of an airplane's side rudder illustrates the applicability of the method to typical engineering problem
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