15,720 research outputs found
Ranking relations using analogies in biological and information networks
Analogical reasoning depends fundamentally on the ability to learn and
generalize about relations between objects. We develop an approach to
relational learning which, given a set of pairs of objects
,
measures how well other pairs A:B fit in with the set . Our work
addresses the following question: is the relation between objects A and B
analogous to those relations found in ? Such questions are
particularly relevant in information retrieval, where an investigator might
want to search for analogous pairs of objects that match the query set of
interest. There are many ways in which objects can be related, making the task
of measuring analogies very challenging. Our approach combines a similarity
measure on function spaces with Bayesian analysis to produce a ranking. It
requires data containing features of the objects of interest and a link matrix
specifying which relationships exist; no further attributes of such
relationships are necessary. We illustrate the potential of our method on text
analysis and information networks. An application on discovering functional
interactions between pairs of proteins is discussed in detail, where we show
that our approach can work in practice even if a small set of protein pairs is
provided.Comment: Published in at http://dx.doi.org/10.1214/09-AOAS321 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Single spin asymmetries in inclusive hadron production from SIDIS to hadronic collisions: universality and phenomenology
In a perturbative QCD approach, with inclusion of spin and transverse
momentum effects, experimental data on azimuthal asymmetries observed in
polarized semi-inclusive deeply inelastic scattering and e+ e- annihilations
can be used to determine the Sivers, transversity and Collins soft functions.
By using these functions, within the same scheme, we predict p(transv.
polarized) p -> h + X single spin asymmetries in remarkable agreement with RHIC
experimental data.Comment: 5 pages, 6 ps figure
Lambda polarization in pp -> p\Lambda K^+ \pi^+\pi^-\pi^+\pi^-
We show that there is a correlation between the invariant mass of the
produced \Lambda K^+, \Lambda K^+\pi^+\pi^- or \Lambda K^+ \pi^+\pi^-\pi^+\pi^-
system in the exclusive reaction pp\to p\Lambda K^+\pi^+\pi^-\pi^+\pi^- and the
longitudinal or transverse momentum of . Together with the
longitudinal and transverse momentum dependence of Lambda polarization observed
in inclusive reactions, such a correlation implies a dependence of Lambda
polarization on these invariant masses. The qualitative features of this
dependence are consistent with the recent observation by E766 collaboration at
BNL. A quantitative estimation has been made using an event generator for
collisions. A detailed comparison with the data is made.Comment: 10 pages with 3 figures, submitted to J. Phys.
Phosphate post-treatment of cerium-based conversion coatings on Al 2024-T3
Phosphate post-treatment of cerium-based conversion coatings (CeCCs) on high strength aluminum alloys can significantly improve corrosion resistance. As-deposited CeCCs exhibit corrosion pits and salt tails across the specimen surface after 3 days of exposure, but post-treated CeCCs have withstood 14 days of salt spray exposure without visibly corroding. The morphology, phase, and electrochemical properties of spray deposited CeCCs were affected by post-treatment parameters such as immersion time, solution temperature, and phosphate source. The best performing coatings were post-treated in aqueous orthophosphate solutions for at least 5 min at temperatures of at least 85â°C. These conditions converted cerium hydroxy/peroxy species in the as-deposited CeCC to hydrated CePOâ and minimized cracks in the coating. Despite demonstrating the kinetic dependence of processes active during post-treatment, these results suggested that the corrosion resistance of CeCCs was dependent on the coating phase and morphology. Using an aqueous precipitation technique, hydrated CePOâ coatings were directly deposited onto Al 2024-T3 substrates and compared to as-deposited and post-treated CeCCs. After salt spray exposure, analysis revealed the formation of pits in the alloy where the substrate was exposed by cracks in the directly deposited CePOâ coating. Post-treated CeCC specimens did not exhibit corrosion at crack/substrate interfaces, indicating that CeCCs can provide electrochemical protection. Post-treated CeCCs also formed an interfacial reaction layer at CeCC/substrate interfaces, a response not observed for directly deposited CePOâ coatings or as-deposited CeCCs. These results demonstrate that post-treated CeCCs are not static barrier coatings, but respond actively to corrosion --Abstract, page iv
Modelling the effects of rehabilitation and changed agricultural practices in a saline-affected rural catchment
The Bremer river catchment, on the South-coast of Western Australia, is typical of most river catchments in this region in that it has been seriously affected by sedimentation, salinisation and eutrophication brought on by the gradual dominance of agricultural land management practices. Vegetated rehabilitation and changed agricultural land management practices (ie minimum / zero tillage) have now been widely adopted throughout the catchment in response to these degradation issues. This study examined the potential impact minimum / zero tillage, vegetated rehabilitation and remnant vegetation could have on both a farm and catchment wide scale. A Geographical Information System was developed to identify spatial variability evident throughout the catchment. Three zones were developed by the system to account for spatial variability. Field studies were undertaken to sample the surface runoff flow from areas under the Remnant Vegetation, Vegetated Rehabilitation and Minimum / Zero Tillage land management practice in each of the three zones. Runoff was sampled using a modified Gerlach trough. Runoff sampling was synchronised with the occurrence of the first rainfall I runoff event of the year. Phosphorus, sediment and salt concentrations were the main parameters analysed in the runoff samples collected. Following statistical analysis, the results for these parameters were extrapolated to a load per hectare figure. Further analysis of the catchment GIS was undertaken to determine the area of each zone and areas under each land practice in each zone. Two series of modelling scenarios, using the extrapolated load data, were used to determine the immediate and long term restorative effects increasing areas of vegetated rehabilitation could have on both a zone and catchment basis. This study concluded that minimum / zero tillage in the catchment, in combination with further wide-spread adoption of vegetated rehabilitation will have the capacity to reduce catchment degradation caused by eutrophication and sedimentation. Its extensive implementation can address these two forms of degradation by decreasing runoff concentrations of phosphorus and sediment. Salinity problems in the catchment will be indirectly effected through resulting changes to the groundwater table. Additional changes to current land management practices are also necessary for instance fertility testing and fertiliser application-on-need should be incorporated into the minimum / zero tillage land management practice if they haven\u27t been already
Quantum Flux and Reverse Engineering of Quantum Wavefunctions
An interpretation of the probability flux is given, based on a derivation of
its eigenstates and relating them to coherent state projections on a quantum
wavefunction. An extended definition of the flux operator is obtained using
coherent states. We present a "processed Husimi" representation, which makes
decisions using many Husimi projections at each location. The processed Husimi
representation reverse engineers or deconstructs the wavefunction, yielding the
underlying classical ray structure. Our approach makes possible interpreting
the dynamics of systems where the probability flux is uniformly zero or
strongly misleading. The new technique is demonstrated by the calculation of
particle flow maps of the classical dynamics underlying a quantum wavefunction.Comment: Accepted to EP
- âŠ