Search results for "BARD"

Change in geometry of a high Arctic glacier to 1948 to 2013 (Austre Lovénbreen, Svalbard)

2017

International audience; The change of Austre Lovénbreen, a 4.5 km2 land-based glacier along the west coast of Spitsbergen, is investigated using geodetic methods and mass balance measurements over 1948–2013. For 2008−2013, annual mass balances computed on 36-stake measurements were obtained, in addition to annual mass balances reconstructed from the neighbouring glaciers, Midtre Lovénbreen (1968−2007) and Austre Brøggerbreen (1963−1967). The mean rate of glacier retreat for 1948–2013 is −16.7 ± 0.3 m a−1. Fluctuations in area (1948–2013 mean, −0.027 ± 0.002 km2 a−1) showed a slowing as the glacier recedes within its valley from 1990 to 1995. For 1962–2013, the average volume loss calculated…

FUOCO DAL CIELO

2017

The second war told by the images of the bombings taken from above (thanks to the consultation of the English archives) and from the bottom (with the consultation of the firefighters' photo archives) give us back an impossible story of the Second World War. Thinking, living and describing the death that comes from above places us in front of problems that go up to the present day, to the drone wars.

Prefazione a D. Michelon, Palermo al tempo dei bombardamenti. Il racconto del triennio 1940 - 1943 attraverso documenti e testimonianze

2021

The behavior of correlation functions in trans-polyacetylene: quantum Monte Carlo study

2002

We present results of a quantum Monte Carlo simulation of the one-dimensional half-filled Hubbard model to study different correlation functions in the trans-polyacetylene (t-PA) polymer. Magnetic structure of the model in t-PA is studied for a different range values of the Hubbard repulsion interactions, U and V ,w here U 4t , with V ∈[ U/2 ,U ] (t is the hopping matrix elements). In this work, we investigate the behavior of the magnetic correlation functions for different phases transitions between different ordering (antiferromagnetic and ferromagnetic) by varying the nearest-neighbor interactions U and V between different atomic sites. Our results indicate that there is a presence of a …

Reentrant Fulde-Ferrell-Larkin-Ovchinnikov superfluidity in the honeycomb lattice

2017

We study superconducting properties of population-imbalanced ultracold Fermi mixtures in the honeycomb lattice that can be effectively described by the spin-imbalanced attractive Hubbard model in the presence of a Zeeman magnetic field. We use the mean-field theory approach to obtain ground state phase diagrams including some unconventional superconducting phases such as the Fulde--Ferrell--Larkin--Ovchinnikov (FFLO) phase. We show that this phase is characterized by atypical behaviour of the Cooper pairs total momentum in the external magnetic field. We show that the momentum changes its value as well as direction with change of the system parameters. We discuss the influence of van Hove s…

Single-particle properties of the Hubbard model in a novel three-pole approximation

2017

We study the 2D Hubbard model using the Composite Operator Method within a novel three-pole approximation. Motivated by the long-standing experimental puzzle of the single-particle properties of the underdoped cuprates, we include in the operatorial basis, together with the usual Hubbard operators, a field describing the electronic transitions dressed by the nearest-neighbor spin fluctuations, which play a crucial role in the unconventional behavior of the Fermi surface and of the electronic dispersion. Then, we adopt this approximation to study the single-particle properties in the strong coupling regime and find an unexpected behavior of the van Hove singularity that can be seen as a prec…

Challenges in truncating the hierarchy of time-dependent reduced density matrices equations

2012

In this work, we analyze the Born, Bogoliubov, Green, Kirkwood, and Yvon (BBGKY) hierarchy of equations for describing the full time evolution of a many-body fermionic system in terms of its reduced density matrices (at all orders). We provide an exhaustive study of the challenges and open problems linked to the truncation of such a hierarchy of equations to make them practically applicable. We restrict our analysis to the coupled evolution of the one- and two-body reduced density matrices, where higher-order correlation effects are embodied into the approximation used to close the equations. We prove that within this approach, the number of electrons and total energy are conserved, regardl…

Depth profiles of aggregate centers and nanodefects in LiF crystals irradiated with 34 MeV 84Kr, 56 MeV 40Ar and 12 MeV 12C ions

2018

I. Manika, J. Maniks and R. Zabels acknowledge the national project IMIS2. A. Dauletbekova, A. Akilbekov, M. Zdorovets and A. Seitbayev acknowledge the GF AP05134257of Ministry of Education and Science the Republic of Kazakhstan.

Gas-phase ion chemistry of protonated melatonin

2009

The gas-phase ion chemistry of protonated melatonin has been investigated by mass spectrometric (MS) techniques involving chemical ionisation, fast atom bombardment and electrospray ionisation. Either naturally-occurring or collision-induced decomposition experiments have been carried out using side chain tetra-deuterium-labelled derivatives, as well as the corresponding N–D derivatives obtained by exchange with D2O. The analysis of experimental results allows definite pathways for the formation of the ion at m/z 174 to be assigned and sheds some more light on the overall fragmentation pathways. Experiments on labelled derivatives evidenced H–D scrambling processes during fragmentation.

Les «Epistolae Familiares» de Petrarca en el «Curial»

2018

L’autor de Curial e Güelfa, novel·la de cavalleria humanística escrita a Itàlia pels anys 1445- 1448 en llengua catalana, era coneixedor i estudiós de les Epistolae Familiares de Francesco Petrarca, com ha posat en evidència la crítica literària. Es recullen ací les aportacions al respecte de diferents autors, que són ampliades amb altres connexions intertextuals i temàtiques entre ambdues obres. S’anota, de pas, l’interés que l’humanista llombard Guiniforte Barzizza posà a divulgar l’obra de Petrarca a la cort napolitana d’Alfons el Magnànim (gràcies a l’amistat que mantenia amb alguns cavallers i diplomàtics valencians) com un indicador a tenir en compte a l’hora de contextualitzar correc…