21,776 research outputs found
Two Observations of Predation on Lepidoptera
(excerpt)
During the early afternoon of 25 August, 1977, a large European mantid, Mantis religiosa Linnaeus, was observed feeding on an adult male monarch butterfly, Donaus p. plexippus Linnaeus (Danaidae) while clinging to the flower head of a blazing star plant (Liatris sp.) on a cactus prairie at the Allegan State Game Area, Allegan County, Michigan
Yangian Symmetry, S-Matrices and Bethe Ansatz for the AdS5 x S5 Superstring
We discuss the relation between the recently derived bound state S-matrices
for the AdS5 x S5 superstring and Yangian symmetry. We will study the relation
between this Yangian symmetry and the Bethe ansatz. In particular we can use it
to derive the Bethe equations for bound states.Comment: Proceedings of the work presented at the 4-th EU RTN Workshop in
Varna, Bulgari
Bound States, Yangian Symmetry and Classical r-matrix for the AdS5 x S5 Superstring
We show that the recently found S-matrices describing the scattering of
two-particle bound states of the light-cone string sigma model on AdS5 x S5 are
compatible with Yangian symmetry. In case the invariance with respect to the
centrally extended su(2|2) algebra is not sufficient to fully specify the
scattering matrix, the requirement of Yangian symmetry provides an alternative
to the Yang-Baxter equation and leads to a complete, up to an overall phase,
determination of the S-matrix. We then compare the semi-classical limit of the
bound state S-matrices with the universal classical r-matrix by Beisert and
Spill evaluated in the corresponding bound state representations and find
perfect agreement.Comment: V3: Published version, reference adde
Impact Evaluations and Development: Nonie Guidance on Impact Evaluation
In international development, impact evaluation is principally concerned with final results of interventions (programs, projects, policy measures, reforms) on the welfare of communities, households, and individuals, including taxpayers and voters. Impact evaluation is one tool within the larger toolkit of monitoring and evaluation (including broad program evaluations, process evaluations, ex ante studies, etc.).The Network of Networks for Impact Evaluation (NONIE) was established in 2006 to foster more and better impact evaluations by its membership -- the evaluation networks of bilateral and multilateral organizations focusing on development issues, as well as networks of developing country evaluators. NONIE's member networks conduct a broad set of evaluations, examining issues such as project and strategy performance, institutional development, and aid effectiveness. By sharing methodological approaches and promoting learning by doing on impact evaluations, NONIE aims to promote the use of this more specific approach by its members within their larger portfolio of evaluations. This document, by Frans Leeuw and Jos Vaessen, has been developed to support this focus.For development practitioners, impact evaluations play a keyrole in the drive for better evidence on results and development effectiveness. They are particularly well suited to answer important questions about whether development interventions do or do not work, whether they make a difference, and how cost-effective they are. Consequently, they can help ensure that scarce resources are allocated where they can have the most developmental impact
On Abandoning XLISP-STAT
In'98 the UCLA Department of Statistics, which had been one of the major users of Lisp-Stat, and one of the main producers of Lisp-Stat code, decided to switch to S/R. This paper discusses why this decision was made, and what the pros and the cons were.
- …