2,478 research outputs found
Standard Young Tableaux and Colored Motzkin Paths
In this paper, we propose a notion of colored Motzkin paths and establish a
bijection between the -cell standard Young tableaux (SYT) of bounded height
and the colored Motzkin paths of length . This result not only gives a
lattice path interpretation of the standard Young tableaux but also reveals an
unexpected intrinsic relation between the set of SYTs with at most rows
and the set of SYTs with at most 2d rows.Comment: 21 page
Excited states of spherium
We report analytic solutions of a recently discovered quasi-exactly solvable
model consisting of two electrons, interacting {\em via} a Coulomb potential,
but restricted to remain on the surface of a -dimensional sphere.
Polynomial solutions are found for the ground state, and for some higher
() states. Kato cusp conditions and interdimensional degeneracies are
discussed.Comment: 6 pages, 2 figures, to appear in Mol. Phy
Statistics of leading digits leads to unification of quantum correlations
We show that the frequency distribution of the first significant digits of
the numbers in the data sets generated from a large class of measures of
quantum correlations, which are either entanglement measures, or belong to the
information-theoretic paradigm, exhibit a universal behaviour. In particular,
for Haar uniformly simulated arbitrary two-qubit states, we find that the
first-digit distribution corresponding to a collection of chosen computable
quantum correlation quantifiers tend to follow the first-digit law, known as
the Benford's law, when the rank of the states increases. Considering a
two-qubit state which is obtained from a system governed by paradigmatic spin
Hamiltonians, namely, the XY model in a transverse field, and the XXZ model, we
show that entanglement as well as information theoretic measures violate the
Benford's law. We quantitatively discuss the violation of the Benford's law by
using a violation parameter, and demonstrate that the violation parameter can
signal quantum phase transitions occurring in these models. We also comment on
the universality of the statistics of first significant digits corresponding to
appropriate measures of quantum correlations in the case of multipartite
systems as well as systems in higher dimensions.Comment: v1: 11 pages, 5 figures, 2 tables; v2: 11 pages, 6 figures, 2 tables,
new results added, extended version of the published pape
Synthesis of Positron Emission Tomography (PET) Images via Multi-channel Generative Adversarial Networks (GANs)
Positron emission tomography (PET) image synthesis plays an important role,
which can be used to boost the training data for computer aided diagnosis
systems. However, existing image synthesis methods have problems in
synthesizing the low resolution PET images. To address these limitations, we
propose multi-channel generative adversarial networks (M-GAN) based PET image
synthesis method. Different to the existing methods which rely on using
low-level features, the proposed M-GAN is capable to represent the features in
a high-level of semantic based on the adversarial learning concept. In
addition, M-GAN enables to take the input from the annotation (label) to
synthesize the high uptake regions e.g., tumors and from the computed
tomography (CT) images to constrain the appearance consistency and output the
synthetic PET images directly. Our results on 50 lung cancer PET-CT studies
indicate that our method was much closer to the real PET images when compared
with the existing methods.Comment: 9 pages, 2 figure
A Software Process Improvement Roadmap for IEC 62304: an Expert Review
Manufacturers of medical devices must comply with certain legislation and regulations before they can market their products in the European Union (EU). The EU has introduced this legislation and regulation to provide the frameworks by which manufacturers can produce safe and effective medical devices in a consistent manner. The EU has accomplished this by way of Medical Device Directives and harmonised standards. Manufactures, by demonstrating compliance with a harmonised standard, can be presumed to have complied with the essential requirements of the legislation. IEC 62304 Medical device software – Software lifecycle processes is a harmonised standard. However, the standard provides no clear directions for meeting the requirements of the standard. A Software Process Improvement (SPI) Roadmap for IEC 62304:2006 has been developed as a method for aiding medical device software development organizations in implementing the standard. The Roadmap is divided into two levels, the high level consists of the Activities and Tasks necessary for the im-plementation of the standard, while the low level contains the Design Patterns and How-to artefacts linked to the Tasks. This paper presents the findings from the expert review of the high level roadmap
Motivation for employees to participate in workplace health promotion: literature review
According to the Luxembourg Declaration, workplace health promotion (WHP) is the combined efforts
of employers, workers and society to improve the health and wellbeing of people at work. This can be
achieved by: improving work organisation and the work environment; promoting the active
participation of all stakeholders in the process; and encouraging personal development. It is important
to note that WHP aims to be a complementary support for, but not a replacement of, workplace risk
management. Proper risk management is an essential foundation for a successful WHP programme.
Regarding actual participation in WHP activities, the literature suggests that the number of participants
often tends to be rather low once the WHP project is actually in progress. Therefore, it is pertinent to
investigate how organisations are able to motivate their employees to participate in WHP activities in
both the short- and long term. At the same time it should be kept in mind that employee participation in
health promotion activities is totally voluntary.
The aim of this report was to conduct a review of the available literature to identify the motivating
factors for employees to participate in WHP. This knowledge can be used to improve WHP
programmes and, consequently, the participation rates. The findings section of the report is divided
into two key areas. The first section outlines and describes some of the key findings from the literature
concerning workers’ motivation to participate in WHP; and the second examines the contributory role
diversity may play in worker participation and recruitment
Preliminary characterization of a Moroccan honey with a predominance of Bupleurum spinosum pollen
Honey with Bupleurum spinosum (zandaz) as a main pollen source has not been the subject of previous detailed study. Therefore, twelve Moroccan samples of this honey were subjected to melissopalynological, physicochemical and microbiological quality characterization, as well as antioxidant activity assessment. From a quality point of view, almost all samples were within the limits established by Codex Alimentarius, and/or the European legislation. All samples presented predominance of B. spinosum pollen (more than 48%). Relatively high levels of trehalose (1.3-4.0 g/100 g) and melezitose (1.5-2.8 g/100 g) were detected. Those sugars, not common in monofloral honeys, could be used as an important factor to discriminate zandaz honey. Flavonoid content correlated positively with the honey color, melanoidin and polyphenol content, and negatively with the IC50 values of scavenging ABTS (2,2' - azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals, while proline amount correlated negatively with IC50 values of nitric oxide scavenging activity and chelating power. This correlation supports the use of anti-oxidant activities as important variables for PCA (principal component analysis). Both components explained 70% from the given data, and showed certain homogeneity upon analyzed samples independent of the region, suggesting the importance of B. spinosum nectar in the resulting honey characteristics.Fundacao para a Ciencia e Tecnologia for Research Center [UID/BIM/04773/2013 CBMR 1334, UID/AGR/00239/2013, UID/BIA/04050/2013 (POCI-01-0145-FEDER-007569)]; ERDF through the COMPETE - Programa Operacional Competitividade e Internacionalizacao (POCI
Investing in Prevention or Paying for Recovery - Attitudes to Cyber Risk
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Broadly speaking an individual can invest time and effort to avoid becoming victim to a cyber attack and/or they can invest resource in recovering from any attack. We introduce a new game called the pre-vention and recovery game to study this trade-off. We report results from the experimental lab that allow us to categorize different approaches to risk taking. We show that many individuals appear relatively risk loving in that they invest in recovery rather than prevention. We find little difference in behavior between a gain and loss framing
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