6,834 research outputs found
Numerical precision radiative corrections to the Dalitz plot of baryon semileptonic decays including the spin-momentum correlation of the decaying and emitted baryons
We calculate the radiative corrections to the angular correlation between the
polarization of the decaying and the direction of the emitted spin one-half
baryons in the semileptonic decay mode. The final results are presented, first,
with the triple integration of the bremsstrahlung photon ready to be performed
numerically and, second, in an analytical form. A third presentation of our
results in the form of numerical arrays of coefficients to be multiplied by the
quadratic products of form factors is discussed. This latter may be the most
practical one to use in Monte Carlo simulations. A series of crosschecks is
performed. Previous results to order (alpha/pi)(q/M_1) for the decays of
unpolarized baryons are reviewed, too, where q is the momentum transfer and M_1
is the mass of the decaying baryon. This paper is self-contained and organized
to make it accessible and reliable in the analysis of the Dalitz plot of
precision experiments involving heavy quarks and is not compromised to fixing
the form factors at predetermined values. It is assumed that the real photons
are kinematically discriminated. Otherwise, our results have a general
model-independent applicability.Comment: 34 pages, 4 tables, no figures. Some sections have been shortened.
Conclusions remain unchange
Generalizing Boolean Satisfiability I: Background and Survey of Existing Work
This is the first of three planned papers describing ZAP, a satisfiability
engine that substantially generalizes existing tools while retaining the
performance characteristics of modern high-performance solvers. The fundamental
idea underlying ZAP is that many problems passed to such engines contain rich
internal structure that is obscured by the Boolean representation used; our
goal is to define a representation in which this structure is apparent and can
easily be exploited to improve computational performance. This paper is a
survey of the work underlying ZAP, and discusses previous attempts to improve
the performance of the Davis-Putnam-Logemann-Loveland algorithm by exploiting
the structure of the problem being solved. We examine existing ideas including
extensions of the Boolean language to allow cardinality constraints,
pseudo-Boolean representations, symmetry, and a limited form of quantification.
While this paper is intended as a survey, our research results are contained in
the two subsequent articles, with the theoretical structure of ZAP described in
the second paper in this series, and ZAP's implementation described in the
third
Generalizing Boolean Satisfiability II: Theory
This is the second of three planned papers describing ZAP, a satisfiability
engine that substantially generalizes existing tools while retaining the
performance characteristics of modern high performance solvers. The fundamental
idea underlying ZAP is that many problems passed to such engines contain rich
internal structure that is obscured by the Boolean representation used; our
goal is to define a representation in which this structure is apparent and can
easily be exploited to improve computational performance. This paper presents
the theoretical basis for the ideas underlying ZAP, arguing that existing ideas
in this area exploit a single, recurring structure in that multiple database
axioms can be obtained by operating on a single axiom using a subgroup of the
group of permutations on the literals in the problem. We argue that the group
structure precisely captures the general structure at which earlier approaches
hinted, and give numerous examples of its use. We go on to extend the
Davis-Putnam-Logemann-Loveland inference procedure to this broader setting, and
show that earlier computational improvements are either subsumed or left intact
by the new method. The third paper in this series discusses ZAPs implementation
and presents experimental performance results
Dynamic Backtracking
Because of their occasional need to return to shallow points in a search
tree, existing backtracking methods can sometimes erase meaningful progress
toward solving a search problem. In this paper, we present a method by which
backtrack points can be moved deeper in the search space, thereby avoiding this
difficulty. The technique developed is a variant of dependency-directed
backtracking that uses only polynomial space while still providing useful
control information and retaining the completeness guarantees provided by
earlier approaches.Comment: See http://www.jair.org/ for an online appendix and other files
accompanying this articl
FDA Approved? A Critique of the Artificial Insemination Industry in the United States
Artificial insemination by donor is becoming an increasingly popular means to achieving parenthood. While the majority of couples use artificial insemination to overcome fertility problems, many recipients use artificial insemination to avoid passing a genetic disease to their children. However, case studies reveal the inherent dangers of artificial insemination, namely the lack of proper screening methods to avoid passing genetic diseases to children born by artificial insemination. State-by-state regulation, federal guidelines, and private adjudication have all proven to be inadequate methods of regulating the artificial insemination industry. Ginsberg proposes federal regulation as the only means of achieving a safe artificial insemination industry. The proposed federal regulation would include better genetic screening, a more efficient national sperm donor system, and limited disclosure to recipients of artificial insemination and their children. These measures would help to ensure that couples using artificial insemination get what they expect-healthy sperm, a safe artificial insemination process, and ultimately, a healthy child
GIB: Imperfect Information in a Computationally Challenging Game
This paper investigates the problems arising in the construction of a program
to play the game of contract bridge. These problems include both the difficulty
of solving the game's perfect information variant, and techniques needed to
address the fact that bridge is not, in fact, a perfect information game. GIB,
the program being described, involves five separate technical advances:
partition search, the practical application of Monte Carlo techniques to
realistic problems, a focus on achievable sets to solve problems inherent in
the Monte Carlo approach, an extension of alpha-beta pruning from total orders
to arbitrary distributive lattices, and the use of squeaky wheel optimization
to find approximately optimal solutions to cardplay problems. GIB is currently
believed to be of approximately expert caliber, and is currently the strongest
computer bridge program in the world
A SOTL Conversation in the Classroom
Sarah Ginsberg\u27s contribution to this volume explores critical lessons that Sarah learned while teaching using a hybrid model in an introductory special education class. Sarah began the project with an interest in how students perceive hybrid teaching models (part in-class and part online). Given significant movement within the academy toward online and hybrid models, Sarah\u27s insights into how students view this type of learning are important for all of us to examine. Students may not have embraced this model of education as much as they are purported to have done; they identify many of the same challenges (including lack of personal connection) that faculty members do.
What stands out in this chapter is the discussion Sarah engaged in with her students about reflection. As future teachers, Sarah\u27s students no doubt benefited from her example of how teachers need to pay attention to what is happening in their classes, making mid-course corrections as needed. In actively reflecting on issues of big picture versus little picture learning with her students, Sarah brought students into the teaching and learning conversation
Increasing African American Student Success in Speech-Language Pathology Programs
At this time just under 8% of the speech-language pathologists in the United States identify themselves as minorities (ASHA, 2016a) despite the efforts of the American Speech-Language-Hearing Association to increase diversity. African Americans are poorly represented in the field at 3% of the membership (ASHA, 2016a). In order to identify potential mechanisms for increasing the diversity of the field, 11 African American Speech-Language Pathologists were asked to provide recommendations for improving African American student retention in speech-language pathology undergraduate and graduate educational programs. Participants offered recommendations for how to increase the success rate of African American students in speech-language pathology programs, including providing culturally competent and caring mentorship, co-mentoring opportunities in educational programs, and connections to critical resources
Generalizing Boolean Satisfiability III: Implementation
This is the third of three papers describing ZAP, a satisfiability engine
that substantially generalizes existing tools while retaining the performance
characteristics of modern high-performance solvers. The fundamental idea
underlying ZAP is that many problems passed to such engines contain rich
internal structure that is obscured by the Boolean representation used; our
goal has been to define a representation in which this structure is apparent
and can be exploited to improve computational performance. The first paper
surveyed existing work that (knowingly or not) exploited problem structure to
improve the performance of satisfiability engines, and the second paper showed
that this structure could be understood in terms of groups of permutations
acting on individual clauses in any particular Boolean theory. We conclude the
series by discussing the techniques needed to implement our ideas, and by
reporting on their performance on a variety of problem instances
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