991 research outputs found
A Pseudo Random Numbers Generator Based on Chaotic Iterations. Application to Watermarking
In this paper, a new chaotic pseudo-random number generator (PRNG) is
proposed. It combines the well-known ISAAC and XORshift generators with chaotic
iterations. This PRNG possesses important properties of topological chaos and
can successfully pass NIST and TestU01 batteries of tests. This makes our
generator suitable for information security applications like cryptography. As
an illustrative example, an application in the field of watermarking is
presented.Comment: 11 pages, 7 figures, In WISM 2010, Int. Conf. on Web Information
Systems and Mining, volume 6318 of LNCS, Sanya, China, pages 202--211,
October 201
Generation of arbitrary two dimensional motional state of a trapped ion
We present a scheme to generate an arbitrary two-dimensional quantum state of
motion of a trapped ion. This proposal is based on a sequence of laser pulses,
which are tuned appropriately to control transitions on the sidebands of two
modes of vibration. Not more than laser pulses are needed to
generate a pure state with upper phonon number and in the and
direction respectively.Comment: to appear in PR
Generation of two-mode nonclassical states and a quantum phase gate operation in trapped ion cavity QED
We propose a scheme to generate nonclassical states of a quantum system,
which is composed of the one-dimensional trapped ion motion and a single cavity
field mode. We show that two-mode SU(2) Schr\"odinger-cat states, entangled
coherent states, two-mode squeezed vacuum states and their superposition can be
generated. If the vibration mode and the cavity mode are used to represent
separately a qubit, a quantum phase gate can be implemented.Comment: to appear in PR
The K^*_0(800) scalar resonance from Roy-Steiner representations of pi K scattering
We discuss the existence of the light scalar meson K^*_0(800) (also called
kappa) in a rigorous way, by showing the presence of a pole in the pi K --> pi
K amplitude on the second Riemann sheet. For this purpose, we study the domain
of validity of two classes of Roy-Steiner representations in the complex energy
plane. We prove that one of them is valid in a region sufficiently broad in the
imaginary direction. From this representation, we compute the l=0 partial wave
in the complex plane with neither additional approximation nor model
dependence, relying only on experimental data. A scalar resonance with
strangeness S=1 is found with the following mass and width: E_kappa = 658 \pm
13 MeV and Gamma_kappa = 557 \pm 24 MeV.Comment: 16 pages, 8 figures. Domain of validity of a Roy-Steiner
representation corrected and enlarged, and features of the K^*_0(800) pole
discussed in more details. Conclusions unchange
Der Beitrag des Personalmanagements zum Unternehmenserfolg. Eine Metaanalyse nach 20 Jahren Erfolgsfaktorenforschung
Die Metaanalyse beruht auf 61 Primärstudien, die zwischen 1985 und 2003 in internationalen Zeitschriften veröffentlicht wurden und den statistischen Zusammenhang zwischen Personalmanagementmaßnahmen und dem Unternehmenserfolg untersucht haben. Die Analyse ergibt einen positiven Gesamteffekt, der aber nur für Teilgruppen signifikant ist. Aufgeschlüsselt nach Personalfunktionen sind vor allem die Effekte für den Weiterbildungsaufwand, für den Anteil variabler Vergütung und den Rekrutierungsaufwand signifikant - die beiden ersteren allerdings mit abnehmender Signifikanz im Zeitverlauf. Darüber hinaus zeichnen sich auch für die Förderung der Work Life Balance und eine Personalpolitik, die auf die Förderung des individuellen Commitment abzielt, signifikante Effekte ab. Das Ergebnis lässt sich durch ein Zusammenspiel von "First Mover"- und Institutionalisierungseffekten erklären. Die Analyse zeigt auch, dass die Ergebnisse von Erfolgsfaktorenstudien stark durch die Wahl der Erfolgsvariable, jedoch weniger durch Moderatorvariablen, wie die Unternehmensgröße oder das Untersuchungsland beeinflusst werden. Für die weitere Personalerfolgsfaktorenforschung ergibt sich die Notwendigkeit einer weitergehenden Standardisierung in der Operationalisierung der Untersuchungsvariablen.This article presents the results of a meta-analysis based on 61 studies investigating the link between human resource management practices and organisational performance which were published between 1985 and 2003 in international peer-reviewed journals. Although the analysis shows an overall positive effect, it is significant for specific HR practices only. Looking more closely at specific human resource management practices, the effect is particularly significant for efforts in recruitment and selection, investments in training and variable pay. For the last two HR practices, the effects are significant for subgroups only and become weaker during the last decade. Significant effects can be expected for the promotion of the work-life-balance, and for a human resource policy encouraging individual commitment. These effects are, however, uncertain due to the small number of studies. The main results can be explained by "firstmover"- and institutionalising effects. The meta-analysis also shows that the results of performance factor studies are strongly influenced by the choice of the performance variable, and less impacted by control variables (organisational size, country). In future research into human resource performance factors it will be necessary to standardise the operationalisation of the variables under examination
An investigation of the potential application of chitosan/aloe-based membranes for regenerative medicine
A significant number of therapeutics derived from natural polymers and plants have been developed to
replace or to be used in conjunction with existing dressing products. The use of the therapeutic properties
of aloe vera could be very useful in the creation of active wound dressing materials. The present work was
undertaken to examine issues concerning structural features, topography, enzymatic degradation behavior,
antibacterial activity and cellular response of chitosan/aloe vera-based membranes. The chitosan/aloe
vera-based membranes that were developed displayed satisfactory degradation, roughness, wettability
and mechanical properties. A higher antibacterial potency was displayed by the blended membranes.
Moreover, in vitro assays demonstrated that these blended membranes have good cell compatibility with
primary human dermal fibroblasts. The chitosan/aloe vera-based membranes might be promising wound
dressing materials.The authors acknowledge financial support from the Portuguese Foundation for Science and Technology (grants SFRH/BPD/45307/2008 and SFRH/BD/64601/2009), the "Fundo Social Europeu", and the "Programa Diferencial de Potencial Humano". This work was partially supported by the FEDER through POCTEP 0330_IBEROMARE_1_P
Robust statistics towards detection of the 21 cm signal from the Epoch of Reionization
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.
We explore methods for robust estimation of the 21 cm signal from the Epoch of Reionization (EoR). A Kernel Density Estimator (KDE) is introduced for measuring the spatial temperature fluctuation power spectrum from the EoR. The KDE estimates the underlying probability distribution function of fluctuations as a function of spatial scale, and contains different systematic biases and errors to the typical approach to estimating the fluctuation power spectrum. Extraction of histograms of visibilities allows moments analysis to be used to discriminate foregrounds from 21 cm signal and thermal noise. We use the information available in the histograms, along with the statistical dis-similarity of foregrounds from two independent observing fields, to robustly separate foregrounds from cosmological signal, while making no assumptions about the Gaussianity of the signal. Using two independent observing fields to robustly discriminate signal from foregrounds is crucial for the analysis presented in this paper. We apply the techniques to 13 h of Murchison Widefield Array EoR data over two observing fields. We compare the output to that obtained with a comparative power spectrum estimation method, and demonstrate the reduced foreground contamination using this approach. Using the second moment obtained directly from the KDE distribution functions yields a factor of 2-3 improvement in power for k < 0.3 h Mpc-1 compared with a matched delay space power estimator, while weighting data by additional statistics does not offer significant improvement beyond that available for thermal noise-only weights
The effect of oxygen stoichiometry on electrical transport and magnetic properties of La0.9Te0.1MnOy
The effect of the variation of oxygen content on structural, magnetic and
transport properties in the electron-doped manganites La0.9Te0.1MnOy has been
investigated. All samples show a rhombohedral structure with the space group .
The Curie temperature decreases and the paramagnetic-ferromagnetic (PM-FM)
transition becomes broader with the reduction of oxygen content. The
resistivity of the annealed samples increases slightly with a small reduction
of oxygen content. Further reduction in the oxygen content, the resistivity
maximum increases by six orders of magnitude compared with that of the
as-prepared sample, and the r(T) curves of samples with y = 2.86 and y = 2.83
display the semiconducting behavior () in both high-temperature PM phase and
low-temperature FM phase, which is considered to be related to the appearance
of superexchange ferromagnetism (SFM) and the localization of carriers. The
results are discussed in terms of the combined effects of the increase in the
Mn2+/(Mn2++Mn3+) ratio, the partial destruction of double exchange (DE)
interaction, and the localization of carriers due to the introduction of oxygen
vacancies in the Mn-O-Mn network.Comment: 20 pages, 8 figure
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