1,420 research outputs found
Reconstructing Rational Functions with
We present the open-source library for the
reconstruction of multivariate rational functions over finite fields. We
discuss the involved algorithms and their implementation. As an application, we
use in the context of integration-by-parts reductions and
compare runtime and memory consumption to a fully algebraic approach with the
program .Comment: 46 pages, 3 figures, 6 tables; v2: matches published versio
Education, Information, and Improved Health: Evidence from Breast Cancer Screening
While it is well known that education strongly predicts health, less is known as to why. One reason might be that education improves health-care decision making. In this paper we attempt to disentangle improved decision making from other effects of education, and to quantify how large an impact it has on both a patient’s demand for health services, and that demand’s sensitivity to objective risk factors. We do this by estimating a simple structural model of information acquisition and health decisions for data on women’s self-reported breast-cancer risk and screening behavior. This allows us to separately identify differences in the ability to process health information and differences in overall demand for health. Our results suggest that the observed education gradient in screening stems from a higher willingness-to-pay for health among the educated, but that the main reason why the educated respond more to risk factors in their screening decision is because they are much better informed about the risk factors they face.education, allocative efficiency, health
Fertility transitions along the extensive and intensive margins
This paper examines the fertility transition through a new lens: the extensive margin. Parents with high levels of children might substitute quality for quantity as the constraints on quality relax or those on quantity tighten. However, along the extensive margin, the quantity-quality trade-off cannot operate. At low levels of fertility, we expect quality and quantity to be essential complements. We apply these insights to a large school construction program in the American South during the early 20th century, the Rosenwald Rural Schools Initiative. We find that increased schooling opportunities lead to reductions in fertility among women with high fertility levels, while at the same time inducing higher levels of fertility among women with low levels of fertility. The magnitude of the fertility changes induced in the parent generation is, however, small compared to the changes in fertility induced by the Rosenwald intervention among women that were themselves treated by the intervention. The evidence from the Rosenwald intervention therefore suggests that changes in female opportunity costs induced by increased educational attainment might be among the most important driving forces of the fertility transition.Fertility
Critical behavior of the extended Hubbard model with bond dimerization
Exploiting the matrix-product-state based density-matrix renormalization
group (DMRG) technique we study the one-dimensional extended (-) Hubbard
model with explicit bond dimerization in the half-filled band sector. In
particular we investigate the nature of the quantum phase transition, taking
place with growing ratio between the symmetry-protected-topological and
charge-density-wave insulating states. The (weak-coupling) critical line of
continuous Ising transitions with central charge terminates at a
tricritical point belonging to the universality class of the dilute Ising model
with . We demonstrate that our DMRG data perfectly match with
(tricritical) Ising exponents, e.g., for the order parameter (1/24)
and correlation length (5/9). Beyond the tricritical Ising point, in
the strong-coupling regime, the quantum phase transition becomes first order.Comment: 6 pages, 7 figures, contributions to SCES 201
Effective electroweak Hamiltonian in the gradient-flow formalism
The effective electroweak Hamiltonian in the gradient-flow formalism is constructed for the current-current operators through next-to-next-to-leading-order QCD. The results are presented for two common choices of the operator basis. This allows for a consistent matching of perturbatively evaluated Wilson coefficients and nonperturbative matrix elements evaluated by lattice simulations on the basis of the gradient-flow formalism
Exotic criticality in the dimerized spin-1 chain with single-ion anisotropy
We consider the dimerized spin-1 chain with single-ion anisotropy .
In absence of an explicit dimerization there are three phases: a large-, an
antiferromagnetically ordered and a Haldane phase. This phase structure
persists up to a critical dimerization, above which the Haldane phase
disappears. We show that for weak dimerization the phases are separated by
Gaussian and Ising quantum phase transitions. One of the Ising transitions
terminates in a critical point in the universality class of the dilute Ising
model. We comment on the relevance of our results to experiments on
quasi-one-dimensional anisotropic spin-1 quantum magnets.Comment: Received the Select label. 20 pages, 7 figures, final versio
Your supervisor’s personality impacts you forever
Supervisors are different in their managerial abilities and in how they perceive your work, yet their decisions determine you career outcomes, write Anders Frederiksen, Lisa Kahn, and Fabian Lang
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