3,451 research outputs found
Baryon femtoscopy in heavy-ion collisions at ALICE
In this report, femtoscopic measurements with proton-proton,
antiproton-antiproton, proton-antiproton, proton-antilambda, antiproton-lambda
and lambda-antilambda pairs in Pb-Pb collisions at sqrt(s_NN)=2.76 TeV
registered by ALICE at the LHC are presented. Emission source sizes extracted
from the correlation analysis with (anti)protons grow with the event
multiplicity, as expected. A method to extract the interaction potentials (e.g.
for proton-antilambda and antiproton-lambda pairs) based on femtoscopy analysis
is discussed. The importance of taking into account the so-called residual
correlations induced by pairs contaminated by secondary particles is emphasized
for all analyses mentioned above.Comment: 8 pages, 8 figures, submitted to the European Physical Journal: Web
of Conferences (proceedings of ICNFP 2013 conference
Determination of the electric field gradient and the magnetic field in M\"ossbauer spectrocsopy by half-cube method
This paper presents a new method to determine all components of the electric
field gradient tensor and orientation of the hyperfine magnetic field axis in
the absorber Cartesian frame for M\"ossbauer spectroscopy for nuclear
transitions between levels with spin 3/2 and 1/2. The method can be applied for
single-crystal absorbers with well separated absorption lines in their spectra.
Explicit formulas derived from velocity moments are presented. The new method
allows full separation of the electric quadrupolar and magnetic dipolar
hyperfine interactions by using unpolarized radiation.Comment: 6 page
-algebras associated to -correspondences and applications to mirror quantum spheres
The structure of the -algebras corresponding to even-dimensional mirror
quantum spheres is investigated. It is shown that they are isomorphic to both
Cuntz-Pimsner algebras of certain -correspondences and -algebras of
certain labelled graphs. In order to achieve this, categories of labelled
graphs and -correspondences are studied. A functor from labelled graphs to
-correspondences is constructed, such that the corresponding associated
-algebras are isomorphic. Furthermore, it is shown that
-correspondences for the mirror quantum spheres arise via a general
construction of restricted direct sum.Comment: 27 page
Comparative Analysis Of The Utilisation Of Electronic Commerce And Business In Polish E-shops In The Years 2009-2011
The aim of the article is to present the results of research concerning the utilisation of different aspects of electronic commerce and business in Polish e-shops, based on a number of comparative analyses performed for the years 2009-2011. Some of the presented data concern also the year 2008. The most important aspects covered by the analyses are: international trade and exports of Polish e-shops, marketing aspects of online businesses, the infrastructure and safety of Polish e-shops, their financial results, and also actions planned in order to minimise the effects of the economic crisis. The main conclusions drawn from these analyses, as well as predictions for the future for the Polish e-market, are also presented.Celem artykułu jest zaprezentowanie wyników badań dotyczących wykorzystania różnych aspektów handlu i biznesu elektronicznego w polskich e-sklepach oraz ich komparatywnej analizy wykonanej dla lat 2009-2011. Niektóre zaprezentowane dane dotyczą także roku 2008. Najważniejsze aspekty poruszane w analizach to: międzynarodowy handel i eksport polskich sklepów internetowych, aspekty marketingowe biznesu internetowego, infrastruktura i bezpieczeństwo polskich e-sklepów oraz ich wyniki finansowe, a także działania, które są planowane w celu zminimalizowania skutków kryzysu gospodarczego. W artykule zaprezentowane są również wnioski z wykonanych analiz oraz przewidywania na przyszłość dotyczące polskiego e-rynku
Evolution of entanglement under an Ising-like Hamiltonian with particle losses
We present analytical compact solution for the density matrix and correlation
functions of two collective-macroscopic spins evolving via Ising-like
Hamiltonian in the presence of particle losses. The losses introduce non-local
phase noise which destroys highly entangled states arising in the evolution. On
the other hand, the states appearing at relatively short timescales, possessing
EPR-like entanglement will survive. Applying our solutions to the recently
proposed scheme to entangle two Bose-Einstein condensates, we estimate the
optimal number of atoms for EPR correlations.Comment: 12 pages, 5 Figure
Wpływ barw pułapek Moerickego na liczebność i zróżnicowanie pozyskiwanych pszczół (Apoidea, Hymenoptera)
In deciduous and pine forests the effect of white, yellow and Ыие Moericke traps on
numbers and sped es diversity of Apoidea was assessed. It was proven that the most
useful in forest are white traps. They caught several times greater numbers of bees. The
white traps caught also over 90% of all determined spedes while the yellow ones 56.4%
and the blue traps only 31.6%.W lesie liściastym i sosnowym oceniono wpływ białych, żółtych i niebieskich pułapek
Moerickego na liczebność i zróżnicowanie pozyskiwanych Apoidea. Wykazano, że najbardziej
przydatne do odławiania Apoidea w lasach są pułapki białe. Stwierdzono kilkakrotnie wyższe
liczebności pszczół odłowionych przez białe pułapki. Trafiło też do nich ponad 90% wszystkich
stwierdzonych gatunków, podczas gdy do żółtych 56.4% i 31.6% do niebieskich.Zadanie pt. „Digitalizacja i udostępnienie w Cyfrowym Repozytorium Uniwersytetu Łódzkiego kolekcji czasopism naukowych wydawanych przez Uniwersytet Łódzki” nr 885/P-DUN/2014 dofinansowane zostało ze środków MNiSW w ramach działalności upowszechniającej naukę
How is a data-driven approach better than random choice in label space division for multi-label classification?
We propose using five data-driven community detection approaches from social
networks to partition the label space for the task of multi-label
classification as an alternative to random partitioning into equal subsets as
performed by RAkELd: modularity-maximizing fastgreedy and leading eigenvector,
infomap, walktrap and label propagation algorithms. We construct a label
co-occurence graph (both weighted an unweighted versions) based on training
data and perform community detection to partition the label set. We include
Binary Relevance and Label Powerset classification methods for comparison. We
use gini-index based Decision Trees as the base classifier. We compare educated
approaches to label space divisions against random baselines on 12 benchmark
data sets over five evaluation measures. We show that in almost all cases seven
educated guess approaches are more likely to outperform RAkELd than otherwise
in all measures, but Hamming Loss. We show that fastgreedy and walktrap
community detection methods on weighted label co-occurence graphs are 85-92%
more likely to yield better F1 scores than random partitioning. Infomap on the
unweighted label co-occurence graphs is on average 90% of the times better than
random paritioning in terms of Subset Accuracy and 89% when it comes to Jaccard
similarity. Weighted fastgreedy is better on average than RAkELd when it comes
to Hamming Loss
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