25,058 research outputs found
Generalized Lee-Wick Formulation from Higher Derivative Field Theories
We study a higher derivative (HD) field theory with an arbitrary order of
derivative for a real scalar field. The degree of freedom for the HD field can
be converted to multiple fields with canonical kinetic terms up to the overall
sign. The Lagrangian describing the dynamics of the multiple fields is known as
the Lee-Wick (LW) form. The first step to obtain the LW form for a given HD
Lagrangian is to find an auxiliary field (AF) Lagrangian which is equivalent to
the original HD Lagrangian up to the quantum level. Till now, the AF Lagrangian
has been studied only for N=2 and 3 cases, where is the number of poles of
the two-point function of the HD scalar field. We construct the AF Lagrangian
for arbitrary . By the linear combinations of AF fields, we also obtain the
corresponding LW form. We find the explicit mapping matrices among the HD
fields, the AF fields, and the LW fields. As an exercise of our construction,
we calculate the relations among parameters and mapping matrices for ,
and 4 cases.Comment: 23 pages, version to appear in PRD, we improved the transformation
from HD to LW in Subsection 3.1, added comments on gauge field related with
AF Lagrangians in Conclusion, and added reference
Learning to Translate in Real-time with Neural Machine Translation
Translating in real-time, a.k.a. simultaneous translation, outputs
translation words before the input sentence ends, which is a challenging
problem for conventional machine translation methods. We propose a neural
machine translation (NMT) framework for simultaneous translation in which an
agent learns to make decisions on when to translate from the interaction with a
pre-trained NMT environment. To trade off quality and delay, we extensively
explore various targets for delay and design a method for beam-search
applicable in the simultaneous MT setting. Experiments against state-of-the-art
baselines on two language pairs demonstrate the efficacy of the proposed
framework both quantitatively and qualitatively.Comment: 10 pages, camera read
Geometrization of the Gauge Connection within a Kaluza-Klein Theory
Within the framework of a Kaluza-Klein theory, we provide the geometrization
of a generic (Abelian and non-Abelian) gauge coupling, which comes out by
choosing a suitable matter fields dependence on the extra-coordinates.
We start by the extension of the Nother theorem to a multidimensional
spacetime being the direct sum of a 4-dimensional Minkowski space and of a
compact homogeneous manifold (whose isometries reflect the gauge symmetry); we
show, how on such a ``vacuum'' configuration, the extra-dimensional components
of the field momentum correspond to the gauge charges. Then we analyze the
structure of a Dirac algebra as referred to a spacetime with the Kaluza-Klein
restrictions and, by splitting the corresponding free-field Lagrangian, we show
how the gauge coupling terms outcome.Comment: 10 pages, no figure, to appear on Int. Journ. Theor. Phy
The Use of Online Panel Data in Management Research: A Review and Recommendations
Management scholars have long depended on convenience samples to conduct research involving human participants. However, the past decade has seen an emergence of a new convenience sample: online panels and online panel participants. The data these participants provide—online panel data (OPD)—has been embraced by many management scholars owing to the numerous benefits it provides over “traditional” convenience samples. Despite those advantages, OPD has not been warmly received by all. Currently, there is a divide in the field over the appropriateness of OPD in management scholarship. Our review takes aim at the divide with the goal of providing a common understanding of OPD and its utility and providing recommendations regarding when and how to use OPD and how and where to publish it. To accomplish these goals, we inventoried and reviewed OPD use across 13 management journals spanning 2006 to 2017. Our search resulted in 804 OPD-based studies across 439 articles. Notably, our search also identified 26 online panel platforms (“brokers”) used to connect researchers with online panel participants. Importantly, we offer specific guidance to authors, reviewers, and editors, having implications for both micro and macro management scholars
The influence of climate and population structure on East Asian skeletal morphological variation
Objectives: Recent studies have shown that global variation in body proportions is more complex than previously thought as some traits formerly associated with climate adaptation are better explained by geographic proximity and neutral evolutionary forces. While the recent incorporation of quantitative genetic methodologies has improved understanding of selection due to climate in Africa, Europe, and the Americas; Asia remains underrepresented in recent and historic studies of body form. As ecogeographic studies tend to focus on male morphology, potential sex differences in features influenced by climate and magnitude of selection remain largely unexplored. Materials and Methods: Skeletal measurements encompassing the dimensions of the skull, pelvis, limbs, hands, and feet were collected from male (N = 459) and female (N = 442) remains curated in 13 collections across seven countries in East Asia (N = 901). Osteological data were analyzed with sex and minimum temperature as covariates adjusted by autosomal SNP population genetic distance using univariate Bayesian linear mixed models, and credible intervals were calculated for each trait. Results: Analysis confirmed a relationship between specific traits and climate as well as the magnitude of response in both sexes. After accounting for genetic distance between populations, greater evidence for selection was found acting upon postcranial traits, with the influence of climate on the skull limited primarily to breadth measurements. Larger body size is selected for in colder climates with most measurements increasing with decreased temperature. Selection did not always act upon the same traits in males and females or with the same intensity for both sexes. Discussion: The varied directional selection pressure of climate for different regions of the skeleton and between the sexes underscores the necessity of future ecogeographic research to holistically evaluate body form and to look for sex-specific patterns to better represent population responses to environmental stresses.Includes bibliographical references
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