scholarly journals Asymptotic expansions through the loop-tree duality

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Judith Plenter ◽  
Germán Rodrigo

AbstractAsymptotic expansions of Feynman amplitudes in the loop-tree duality formalism are implemented at integrand-level in the Euclidean space of the loop three-momentum, where the hierarchies among internal and external scales are well-defined. The ultraviolet behaviour of the individual contributions to the asymptotic expansion emerges only in the first terms of the expansion and is renormalized locally in four space-time dimensions. These two properties represent an advantage over the method of Expansion by Regions. We explore different approaches in different kinematical limits, and derive explicit asymptotic expressions for several benchmark configurations.

Mediaevistik ◽  
2018 ◽  
Vol 31 (1) ◽  
pp. 366-366
Author(s):  
Albrecht Classen

Eddic poetry constitutes one of the most important genres in Old Norse or Scandinavian literature and has been studied since the earliest time of modern-day philology. The progress we have made in that field is impressive, considering the many excellent editions and translations, not to mention the countless critical studies in monographs and articles. Nevertheless, there is always a great need to revisit, to summarize, to review, and to digest the knowledge gained so far. The present handbook intends to address all those goals and does so, to spell it out right away, exceedingly well. But in contrast to traditional concepts, the individual contributions constitute fully developed critical article, each with a specialized topic elucidating it as comprehensively as possible, and concluding with a section of notes. Those are kept very brief, but the volume rounds it all off with an inclusive, comprehensive bibliography. And there is also a very useful index at the end. At the beginning, we find, following the table of contents, a list of the contributors, unfortunately without emails, a list of translations and abbreviations of the titles of Eddic poems in the Codex Regius and then elsewhere, and a very insightful and pleasant introduction by Carolyne Larrington. She briefly introduces the genre and then summarizes the essential points made by the individual authors. The entire volume is based on the Eddic Network established by the three editors in 2012, and on two workshops held at St. John’s College, Oxford in 2013 and 2014.


This volume comprises 27 chapters focused on the design and execution of employee survey programs. These chapters reflect the latest advances in technology and analytics and a pervasive emphasis on driving organizational performance and effectiveness. The individual chapters represent the full range of survey-related topics, including design, administration, analysis, feedback, and action-taking. The latest methodological trends and capabilities are discussed including computational linguistics, applications of artificial intelligence, and the use of qualitative methods such as focus groups. Extending beyond traditional employee surveys, contributions include the role of passive data collection as an alternative or supplement in a comprehensive employee listening system. Unique contextual factors are discussed including the use of surveys in a unionized environment. Individual contributions also reflect increasing stakeholder concerns for the protection of privacy among other ethical considerations. Finally, significant clarifications to the literature are provided on the use of surveys for measuring organization culture, strategic climate, and employee engagement.


Author(s):  
J. Adam Carter ◽  
Emma C. Gordon ◽  
Benjamin W. Jarvis

In this introductory chapter, the volume’s editors provide a theoretical background to the volume’s topic and a brief overview of the papers included. The chapter is divided into five parts: Section 1 explains the main contours of the knowledge-first approach, as it was initially advanced by Timothy Williamson in Knowledge and its Limits. In Sections 2–3, some of the key philosophical motivations for the knowledge-first approach are reviewed, and several key contemporary research themes associated with this approach in epistemology, the philosophy of mind and elsewhere are outlined and briefly discussed. The volume’s papers are divided into two broad categories: foundational issues and applications and new directions. Section 4 discusses briefly the scope and aim of the volume as the editors have conceived it, and Section 5 offers an overview of each of the individual contributions in the volume.


Author(s):  
OLGA BALKANOVA ◽  
DMITRY FROLENKOV ◽  
MORTEN S. RISAGER

Abstract The Zagier L-series encode data of real quadratic fields. We study the average size of these L-series, and prove asymptotic expansions and omega results for the expansion. We then show how the error term in the asymptotic expansion can be used to obtain error terms in the prime geodesic theorem.


2021 ◽  
Vol 50 (1) ◽  
pp. 3-11
Author(s):  
Barbara Schulte ◽  
Marina Svensson

This special issue approaches information and communication technologies (ICT) visions and their realisation/implementation at various levels, among different actors and from various perspectives. Conceptually, we distinguish three different dimensions, even though those overlap in the individual contributions as well as in empirical reality – namely ideational, instrumental, and relational. The different contributions address both visions formulated by the Chinese state and by individual actors such as entrepreneurs. Even though the conditions for the use of ICT in China are deeply affected by state governance, this governance is in no way tantamount to one single government. As this issue’s contributions show, state attempts at building a stable cyber-governance are in need of allies and, depending on the allies’ visions and other, competitive visions, the outcomes of these dynamics are seldom truthful realisations of one original grand masterplan.


1997 ◽  
Vol 29 (02) ◽  
pp. 374-387 ◽  
Author(s):  
V. Čekanavičius

The accuracy of the Normal or Poisson approximations can be significantly improved by adding part of an asymptotic expansion in the exponent. The signed-compound-Poisson measures obtained in this manner can be of the same structure as the Poisson distribution. For large deviations we prove that signed-compound-Poisson measures enlarge the zone of equivalence for tails.


2017 ◽  
Vol 13 (08) ◽  
pp. 2097-2113 ◽  
Author(s):  
Shubho Banerjee ◽  
Blake Wilkerson

We study the Lambert series [Formula: see text], for all [Formula: see text]. We obtain the complete asymptotic expansion of [Formula: see text] near [Formula: see text]. Our analysis of the Lambert series yields the asymptotic forms for several related [Formula: see text]-series: the [Formula: see text]-gamma and [Formula: see text]-polygamma functions, the [Formula: see text]-Pochhammer symbol and the Jacobi theta functions. Some typical results include [Formula: see text] and [Formula: see text], with relative errors of order [Formula: see text] and [Formula: see text] respectively.


2005 ◽  
Vol 16 (4) ◽  
pp. 1606-1616 ◽  
Author(s):  
David Michaelson ◽  
Wasif Ali ◽  
Vi K. Chiu ◽  
Martin Bergo ◽  
Joseph Silletti ◽  
...  

The CAAX motif at the C terminus of most monomeric GTPases is required for membrane targeting because it signals for a series of three posttranslational modifications that include isoprenylation, endoproteolytic release of the C-terminal– AAX amino acids, and carboxyl methylation of the newly exposed isoprenylcysteine. The individual contributions of these modifications to protein trafficking and function are unknown. To address this issue, we performed a series of experiments with mouse embryonic fibroblasts (MEFs) lacking Rce1 (responsible for removal of the –AAX sequence) or Icmt (responsible for carboxyl methylation of the isoprenylcysteine). In MEFs lacking Rce1 or Icmt, farnesylated Ras proteins were mislocalized. In contrast, the intracellular localizations of geranylgeranylated Rho GTPases were not perturbed. Consistent with the latter finding, RhoGDI binding and actin remodeling were normal in Rce1- and Icmt-deficient cells. Swapping geranylgeranylation for farnesylation on Ras proteins or vice versa on Rho proteins reversed the differential sensitivities to Rce1 and Icmt deficiency. These results suggest that postprenylation CAAX processing is required for proper localization of farnesylated Ras but not geranygeranylated Rho proteins.


Metrika ◽  
2021 ◽  
Author(s):  
Joscha Krause ◽  
Jan Pablo Burgard ◽  
Domingo Morales

AbstractRegional prevalence estimation requires the use of suitable statistical methods on epidemiologic data with substantial local detail. Small area estimation with medical treatment records as covariates marks a promising combination for this purpose. However, medical routine data often has strong internal correlation due to diagnosis-related grouping in the records. Depending on the strength of the correlation, the space spanned by the covariates can become rank-deficient. In this case, prevalence estimates suffer from unacceptable uncertainty as the individual contributions of the covariates to the model cannot be identified properly. We propose an area-level logit mixed model for regional prevalence estimation with a new fitting algorithm to solve this problem. We extend the Laplace approximation to the log-likelihood by an $$\ell _2$$ ℓ 2 -penalty in order to stabilize the estimation process in the presence of covariate rank-deficiency. Empirical best predictors under the model and a parametric bootstrap for mean squared error estimation are presented. A Monte Carlo simulation study is conducted to evaluate the properties of our methodology in a controlled environment. We further provide an empirical application where the district-level prevalence of multiple sclerosis in Germany is estimated using health insurance records.


2021 ◽  
pp. 074355842110069
Author(s):  
Gabriel Velez

In post-conflict and transitional settings, adolescents are important civic and political actors as potential peacebuilders. Policy and programming often focus on promoting prosocial outcomes for these younger generations, but there has been growing attention to their perspectives and psychological development. Drawing on theory in developmental psychology, adolescents interpret and respond to context in forming ideas about key concepts like peace, understanding society and their place in it, and constructing their orientations toward peace. This study extends current literature by exploring how Colombian adolescents describe peace within the context of a peace process in their country. Ninety-six 15- to 18-year-olds in and around Bogotá, Colombia, were interviewed about peace. Their responses were analyzed inductively using an adapted thematic analysis. Findings indicated that the individual was central to how respondents talked about peace; that is, peace begins and depends on the internal states. From this basis, individuals then created peace through interpersonal relations. There were some differences by respondents’ SES, such as in how respondents described peace as requiring equality in society, but none found for gender or age. This study demonstrates the need to provide concrete opportunities for these adolescents to see individual contributions and broader interpersonal peace as possible.


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