18,235 research outputs found
Hybrid and Conventional Baryons in the Flux-Tube and Quark Models
The status of conventional baryon flux-tubes and hybrid baryons is reviewed.
Recent surprises are that a model prediction indicates that hybrid baryons are
very weakly produced in glue-rich Psi decays, and an analysis of
electro-production data concludes that the Roper resonance is not a hybrid
baryon. The baryon decay flux-tube overlap has been calculated in the flux-tube
model, and is discussed here. The behavior of the overlap follows naive
expectations.Comment: Invited plenary talk presented at the 10th International Symposium on
Meson-Nucleon Physics and the Structure of the Nucleon (MENU 2004), 29 August
- 4 September, Beijing, China. LaTeX, 11 (encapsulated) postscript figures, 6
page
Cost of lifetime immunosuppression coverage for kidney transplant recipients.
On January 1, 2000, Medicare extended the coverage of immunosuppression medications from 3 years to life for elderly and disabled kidney transplant recipients. This research estimates the impact of extending this lifetime coverage to all kidney transplant recipients on Medicare\u27s cash flows. The study finds that extending coverage to all kidney transplant recipients would have increased Medicare\u27s net cash outflows if the coverage were extended for patients of all income levels. There is evidence that extending coverage to only patients in the lowest income quartile could have resulted in a net cost savings to Medicare
Slip casting and extruding shapes of rhenium with metal oxide additives. 1: Feasibility demonstration
The feasibility of fabricating small rhenium parts with metal oxide additives by means of slip casting and extrusion techniques is described. The metal oxides, ZrO2 and HfO2 were stabilized into the cubic phase with Y2O3. Additions of metal oxide to the rhenium of up to 15 weight percent were used. Tubes of 17 mm diameter with 0.5 mm walls were slip cast by adapting current ceramic oxide techniques. A complete cast double conical nozzle demonstrated the ability to meet shapes and tolerances. Extrusion of meter long tubing lengths of 3.9 mm o.d. x 2.3 mm i.d. final dimension is documented. Sintering schedules are presented to produce better than 95% of theoretical density parts. Finished machining was found possible were requried by electric discharge machining and diamond grinding
Evaluation of management measures of software development. Volume 1: Analysis summary
The conceptual model, the data classification scheme, and the analytic procedures are explained. The analytic results are summarized and specific software measures for collection and monitoring are recommended
Unifying Parsimonious Tree Reconciliation
Evolution is a process that is influenced by various environmental factors,
e.g. the interactions between different species, genes, and biogeographical
properties. Hence, it is interesting to study the combined evolutionary history
of multiple species, their genes, and the environment they live in. A common
approach to address this research problem is to describe each individual
evolution as a phylogenetic tree and construct a tree reconciliation which is
parsimonious with respect to a given event model. Unfortunately, most of the
previous approaches are designed only either for host-parasite systems, for
gene tree/species tree reconciliation, or biogeography. Hence, a method is
desirable, which addresses the general problem of mapping phylogenetic trees
and covering all varieties of coevolving systems, including e.g., predator-prey
and symbiotic relationships. To overcome this gap, we introduce a generalized
cophylogenetic event model considering the combinatorial complete set of local
coevolutionary events. We give a dynamic programming based heuristic for
solving the maximum parsimony reconciliation problem in time O(n^2), for two
phylogenies each with at most n leaves. Furthermore, we present an exact
branch-and-bound algorithm which uses the results from the dynamic programming
heuristic for discarding partial reconciliations. The approach has been
implemented as a Java application which is freely available from
http://pacosy.informatik.uni-leipzig.de/coresym.Comment: Peer-reviewed and presented as part of the 13th Workshop on
Algorithms in Bioinformatics (WABI2013
Planar Two-Loop Five-Parton Amplitudes from Numerical Unitarity
We compute a complete set of independent leading-color two-loop five-parton
amplitudes in QCD. These constitute a fundamental ingredient for the
next-to-next-to-leading order QCD corrections to three-jet production at hadron
colliders. We show how to consistently consider helicity amplitudes with
external fermions in dimensional regularization, allowing the application of a
numerical variant of the unitarity approach. Amplitudes are computed by
exploiting a decomposition of the integrand into master and surface terms that
is independent of the parton type. Master integral coefficients are numerically
computed in either finite-field or floating-point arithmetic and combined with
known analytic master integrals. We recompute two-loop leading-color
four-parton amplitudes as a check of our implementation. Results are presented
for all independent four- and five-parton processes including contributions
with massless closed fermion loops.Comment: v3: corrected wrong signs for five-gluon amplitudes with
vanishing tree
Machine learning with the hierarchy‐of‐hypotheses (HoH) approach discovers novel pattern in studies on biological invasions
Research synthesis on simple yet general hypotheses and ideas is challenging in scientific disciplines studying highly context‐dependent systems such as medical, social, and biological sciences. This study shows that machine learning, equation‐free statistical modeling of artificial intelligence, is a promising synthesis tool for discovering novel patterns and the source of controversy in a general hypothesis. We apply a decision tree algorithm, assuming that evidence from various contexts can be adequately integrated in a hierarchically nested structure. As a case study, we analyzed 163 articles that studied a prominent hypothesis in invasion biology, the enemy release hypothesis. We explored if any of the nine attributes that classify each study can differentiate conclusions as classification problem. Results corroborated that machine learning can be useful for research synthesis, as the algorithm could detect patterns that had been already focused in previous narrative reviews. Compared with the previous synthesis study that assessed the same evidence collection based on experts' judgement, the algorithm has newly proposed that the studies focusing on Asian regions mostly supported the hypothesis, suggesting that more detailed investigations in these regions can enhance our understanding of the hypothesis. We suggest that machine learning algorithms can be a promising synthesis tool especially where studies (a) reformulate a general hypothesis from different perspectives, (b) use different methods or variables, or (c) report insufficient information for conducting meta‐analyses
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