Search results for "BEC"

Space-like (vs. time-like) collinear limits in QCD: Is factorization violated?

2012

We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal (process independent). We show that this strict (process-independent) factorization is not valid at one-loop and higher-loop orders in the case of the collinear limit in space-like regions (e.g., collinear radiation from initial-state partons). We introduce a generalized version of all-order collinear factorization, in which the space-like singular factors retain some dependence on the momentum a…

Double collinear splitting amplitudes at next-to-leading order

2013

We compute the next-to-leading order (NLO) QCD corrections to the $1 \to 2$ splitting amplitudes in different dimensional regularization (DREG) schemes. Besides recovering previously known results, we explore new DREG schemes and analyze their consistency by comparing the divergent structure with the expected behavior predicted by Catani's formula. Through the introduction of scalar-gluons, we show the relation among splittings matrices computed using different schemes. Also, we extended this analysis to cover the double collinear limit of scattering amplitudes in the context of QCD+QED.

Triple collinear splitting functions at NLO for scattering processes with photons

2014

We present splitting functions in the triple collinear limit at next-to-leading order. The computation was performed in the context of massless QCD+QED, considering only processes which include at least one photon. Through the comparison of the IR divergent structure of splitting amplitudes with the expected known behavior, we were able to check our results. Besides that we implemented some consistency checks based on symmetry arguments and cross-checked the results among them. Studying photon-started processes, we obtained very compact results.

What is a singular black hole beyond general relativity?

2017

Exploring the characterization of singular black hole spacetimes, we study the relation between energy density, curvature invariants, and geodesic completeness using a quadratic $f(R)$ gravity theory coupled to an anisotropic fluid. Working in a metric-affine approach, our models and solutions represent minimal extensions of General Relativity (GR) in the sense that they rapidly recover the usual Reissner-Nordstr\"{o}m solution from near the inner horizon outwards. The anisotropic fluid helps modify only the innermost geometry. Depending on the values and signs of two parameters on the gravitational and matter sectors, a breakdown of the correlations between the finiteness/divergence of the…

Learning Psychology and becoming psychologists: developing professional identity through group experiential learning

2017

International audience; n this paper, we describe the advantages of an experiential training group, specifically conceived for psychology students, in which the goal was to activate reflection on the internalized social representations of professional identity. Our study showed the results of a pre-post comparison of a one-group intervention. It was aimed to demonstrate that group experiential learning is particularly useful in changing the basis of social representations and may contribute to the construction of a realistic image of both the profession and the professional identity. The research involved 88 students enrolled in a graduate program in clinical psychology. Before and after th…

Sophus A. Reinert, The Academy of Fisticuffs: Political Economy and Commercial Society in Enlightenment Italy (Cambridge, London: Harvard University …

2020

Las batallas de Atapuerca y la (re)escritura novelesca de la historia

2020

La batalla de Atapuerca (1054) constituye un hito en la historia del reino de Navarra. Desde su primera versión historiográfica conservada en la Historia silense (c. 1118-1126), el relato de la batalla de Atapuerca sufrió modificaciones, amplificaciones y refundiciones en su extensa dispersión en el tiempo y el espacio. En este trabajo se lleva a cabo, en un primer momento, una comparación entre distintas versiones latinas (fundamentalmente la Silense, el Chronicon mundi y De rebus Hispaniae) y castellanas de este episodio para luego dar lugar al análisis de una versión tardía del enfrentamiento incluida en el manuscrito 431 de la Biblioteca Nacional de España, códice que dataría de la segu…

Ancient human genomes suggest three ancestral populations for present-day Europeans

2014

We sequenced the genomes of a ∼7,000-year-old farmer from Germany and eight ∼8,000-year-old hunter-gatherers from Luxembourg and Sweden. We analysed these and other ancient genomes1,2,3,4 with 2,345 contemporary humans to show that most present-day Europeans derive from at least three highly differentiated populations: west European hunter-gatherers, who contributed ancestry to all Europeans but not to Near Easterners; ancient north Eurasians related to Upper Palaeolithic Siberians3, who contributed to both Europeans and Near Easterners; and early European farmers, who were mainly of Near Eastern origin but also harboured west European hunter-gatherer related ancestry. We model these popula…

Thermoelectric Heat Exchange and Growth Regulation in a Continuous Yeast Culture

2018

We have designed a thermoelectric heat exchanger (TEHE) for microbial fermentations that is able to produce electric power from a microbial continuous culture using the intrinsic heat generated by microbial growth. While the TEHE was connected, the system proved able to stably self-maintain both the temperature and the optical density of the culture. This paves the way toward a more sustainable operation of microbial fermentations, in which energy could be saved by converting part of the metabolic heat into usable electric power.

Recensione a BART HUELSENBECK, Figures in the Shadows. The Speech of Two Augustan-Age Declaimers, Arellius Fuscus and Papirius Fabianus, Berlin-Bosto…

2022

Review of the volume that is configured as an essay on the declamatory phenomenon as a whole, but above all as a reading entirely internal to the first corpus of declamatory texts by Seneca il Vecchio that has come down to us