Search results for "Correspondence"

Scale-related patterns in the spatial and environmental components of stream macroinvertebrate assemblage variation

2007

Aim  We examined the relative contributions of spatial gradients and local environmental conditions to macroinvertebrate assemblages of boreal headwater streams at three hierarchical extents: bioregion, ecoregion and drainage system. We also aimed to identify the environmental variables most strongly related to assemblage structure at each study scale, and to assess how the importance of these variables is related to regional context and spatial structuring at different scales. Location  Northern Finland (62–68° N, 25–32° E). Methods  Variation in macroinvertebrate data was partitioned using partial canonical correspondence analysis into components explained by spatial variables (nine terms…

GraphoLearn India : The Effectiveness of a Computer-Assisted Reading Intervention in Supporting Struggling Readers of English

2018

India, a country with a population of more than 1.3 billion individuals, houses the world’s second largest educational system. Despite this, 100 of millions of individuals in India are still illiterate. As English medium education sweeps the country, many are forced to learn in a language which is foreign to them. Those living in poverty further struggle to learn English as it tends to be a language which they have no prior exposure to and no support at home for. Low-quality schools and poor instructional methods further exacerbate the problem. Without access to quality education, these individuals continue to struggle and are ultimately never given the chance to break the cycle of poverty.…

Robust Principal Component Analysis of Data with Missing Values

2015

Principal component analysis is one of the most popular machine learning and data mining techniques. Having its origins in statistics, principal component analysis is used in numerous applications. However, there seems to be not much systematic testing and assessment of principal component analysis for cases with erroneous and incomplete data. The purpose of this article is to propose multiple robust approaches for carrying out principal component analysis and, especially, to estimate the relative importances of the principal components to explain the data variability. Computational experiments are first focused on carefully designed simulated tests where the ground truth is known and can b…

Closed Theories, Falsificationism and Non-Cumulative Progress

2020

It is argued that scientific progress occurs not with the cumulative growth of knowledge or when theories get closer to the truth but with discovering new domains and new theories that fit these domains. This horizontal view on the direction of scientific progress (in contrast to vertical, when we aim to get from here to the abstract and ephemeral truth) allows avoiding traditional objections posed by the incommensurability thesis and pessimistic induction, namely, that radical theory changes leave no room for progress. According to this perspective, the discovery of quantum mechanics as a new field of inquiry is a progress in itself, since this discovery had opened up a new distinctive dom…

Entretien : pour une intégration des datadéontologues dans les équipes communication

2018

Conversation autour de l’éthique en pratique : une carrière de communicante sous le signe d’une réflexion et de préoccupations éthiques

2017

Kaluza–Klein theory, AdS/CFT correspondence and black hole entropy

2001

The asymptotic symmetries of the near-horizon geometry of a lifted (near-extremal) Reissner-Nordstrom black hole, obtained by inverting the Kaluza-Klein reduction, explain the deviation of the Bekenstein-Hawking entropy from extremality. We point out the fact that the extra dimension allows us to justify the use of a Virasoro mode decomposition along the time-like boundary of the near-horizon geometry, AdS$_2\times$S$^n$, of the lower-dimensional (Reissner-Nordstrom) spacetime.

Two-twistor particle models and free massive higher spin fields

2015

We present D=3 and D=4 models for massive particles moving in a new type of enlarged spacetime, with D-1 additional vector coordinates, which after quantization lead to the towers of massive higher spin (HS) free fields. Two classically equivalent formulations are presented: one with a hybrid spacetime/bispinor geometry and a second described by a free two-twistor dynamics with constraints. After quantization in the D=3 and D=4 cases, the wave functions are given as functions on the SL(2,R) and SL(2,C) group manifolds respectively, and describe arbitrary on-shell momenta and spin degrees of freedom. Finally, the D=6 case and possible supersymmetric extensions are mentioned.

Constraints on Conformal Windows from Holographic Duals

2009

We analyze a beta function with the analytic form of Novikov-Shifman-Vainshtein-Zakharov result in the five dimensional gravity-dilaton environment. We show how dilaton inherits poles and fixed points of such beta function through the zeros and points of extremum in its potential. Super Yang-Mills and supersymmetric QCD are studied in detail and Seiberg's electric-magnetic duality in the dilaton potential is explicitly demonstrated. Non-supersymmetric proposals of similar functional form are tested and new insights into the conformal window as well as determinations of scheme-independent value of the anomalous dimension at the fixed point are presented.

Holographic duals of 6d RG flows

2018

A notable class of superconformal theories (SCFTs) in six dimensions is parameterized by an integer $N$, an ADE group $G$, and two nilpotent elements $\mu_\mathrm{L,R}$ in $G$. Nilpotent elements have a natural partial ordering, which has been conjectured to coincide with the hierarchy of renormalization-group flows among the SCFTs. In this paper we test this conjecture for $G=\mathrm{SU}(k)$, where AdS$_7$ duals exist in IIA. We work with a seven-dimensional gauged supergravity, consisting of the gravity multiplet and two $\mathrm{SU}(k)$ non-Abelian vector multiplets. We show that this theory has many supersymmetric AdS$_7$ vacua, determined by two nilpotent elements, which are naturally …