966 research outputs found
Multi-parameter formal deformations of ternary hom-Nambu-Lie algebras
In this note, we introduce a notion of multi-parameter formal deformations of
ternary hom-Nambu-Lie algebras. Within this framework, we construct formal
deformations of the three-dimensional Jacobian determinant and of the
cross-product in four-dimensional Euclidean space. We also conclude that the
previously defined ternary q-Virasoro-Witt algebra is a formal deformation of
the ternary Virasoro-Witt algebra.Comment: 6 pages; corrected a typ
Targeted Treatment With Radio Frequency Ablation for Lingual Tonsil
Objectives:Benign enlargement of the lingual tonsils due to various causes may cause symptoms that warrant treatment. Conventional lingual tonsillectomy remains a challenging procedure, and there is no established standard procedure. We aimed to review the patients receiving different methods of lingual tonsil surgery for various indications at our institute.Methods:Retrospective clinical data on all patients with an ablative operation of the tongue base during the 8-year period between 2007 and 2014 at the Helsinki University Hospital, Helsinki, Finland, were reviewed. The larger cohort comprised 35 patients, of whom 26 were men (74%). Ten patients had undergone solely lingual tonsil radio frequency ablation (LTRFA). The minimum follow-up time for all patients was 2 years.Results:Of the 10 patients, 5 patients with LTRFA had been operated on because of symptomatic lingual tonsil hypertrophy and 5 because of periodic fever associated with possible lingual tonsil involvement. In 2 of the 5 patients with periodic fever, the fever cycles ended after the operation. Of the 5 patients, 3 patients with symptomatic lingual tonsil hypertrophy have been non-symptomatic after 1 to 3 treatment sessions. The last 2 patients continue to have persistent symptoms. There were no major complications.Conclusions:Development of new approaches for the management of various lingual tonsil conditions is warranted. Lingual tonsil volume reduction by LTRFA seems to be a treatment alternative with low morbidity but with limited curative effect only.Peer reviewe
On replacement strategies in steady state evolutionary algorithms
Steady State models of Evolutionary Algorithms are widely used, yet surprisingly little attention has been paid to the effects arising from different replacement strategies. This paper explores the use of mathematical models to characterise the selection pressures arising in a selection-only environment. The first part brings together models for the behaviour of seven different replacement mechanisms and provides expressions for various proposed indicators of Evolutionary Algorithm behaviour. Some of these have been derived elsewhere, and are included for completeness, but the majority are new to this paper. These theoretical indicators are used to compare the behaviour of the different strategies. The second part of this paper examines the practical relevance of these indicators as predictors for algorithms' relative performance in terms of optimisation time and reliability. It is not the intention of this paper to come up with a "one size fits all" recommendation for choice of replacement strategy. Although some strategies may have little to recommend them, the relative ranking of others is shown to depend on the intended use of the algorithm to be implemented, as reflected in the choice of performance metrics. © 2007 by the Massachusetts Institute of Technology
Causes for delay before specialist consultation in head and neck cancer
Background: Head and neck cancers are often diagnosed at a late stage, thus resulting in a generally poor prognosis. This is partly attributable to patients' hesitancy in seeking treatment. However, the length and causes of these patient delays remain relatively unknown. Material and methods: We included all new head and neck cancer patients treated at our tertiary care center between 2016 and 2017. Using a patient questionnaire, we collected data on patients' symptoms and other factors related to seeking medical care, and recorded both patient- and primary health care-related delays. We then compared the data collected from these patients to patient and tumor characteristics collected from hospital records, and analyzed various causes for delay before a specialist consultation to the Department of Otorhinolaryngology - Head and Neck Surgery. Results: Among the patients (n = 142) in our study, the median patient delay was 35 d with 73% of patients seeking medical care within 3 months. In comparison, the median primary health-care delay was 20 d. Certain symptoms influenced patient delay. Hoarseness and breathing difficulties correlated with longer patient delay while patients with a lump on the neck had a shorter delay. Patient delay was associated with certain tumor-related factors such as the tumor site and the presence of regional metastases, which resulted in shorter patient delay. None of the patient-related factors appeared to impact delay. Important factors influencing primary health-care delay included the initial location visited and whether any follow-up visit was scheduled or not. Conclusions: Although most patients sought medical advice without a major delay and were adequately referred, we found that long delays existed. Raising awareness of the symptoms of head and neck cancer among general population and health-care providers is probably the best way to get patients to curative treatment without delay.Peer reviewe
COVID-19 information disorder:six types of harmful information during the pandemic in Europe
{Sten Hansson and Kati Orru and Sten Torpan and Asta BĂ€ck and Austeja Kazemekaityte and Sunniva Frislid Meyer and Johanna Ludvigsen and Lucia Savadori and Alessandro Galvagni and Ala PigrĂ©e}, {COVID-19 information disorder: six types of harmful information during the pandemic in Europe}, {Journal of Risk Research}, {24}, {3-4}, {380-393}, {2021}, {Routledge}, {10.1080/13669877.2020.1871058}, { https://doi.org/10.1080/13669877.2020.1871058}The outbreak of a novel coronavirus disease COVID-19 propelled the creation, transmission, and consumption of false information â unverified claims, misleading statements, false rumours, conspiracy theories, and so on â all around the world. When various official or unofficial sources issue erroneous, misleading or contradicting information during a crisis, people who are exposed to this may behave in ways that cause harm to the health and well-being of themselves or others, e.g., by not taking appropriate risk reducing measures or blaming or harassing vulnerable groups. To work towards a typology of informational content that may increase peopleâs vulnerability in the context of the coronavirus pandemic, we explored 98 instances of potentially harmful information that spread in six European countries â France, Italy, Norway, Finland, Lithuania, and Estonia â between March and May 2020. We suggest that during the pandemic, exposure to harmful information may have made people more vulnerable in six ways: (1) by discouraging appropriate protective actions against catching/spreading the virus, (2) by promoting the use of false (or harmful) remedies against the virus, (3) by misrepresenting the transmission mechanisms of the virus, (4) by downplaying the risks related to the pandemic, (5) by tricking people into buying fake protection against the virus or into revealing their confidential information, and (6) by victimising the alleged spreaders of the virus by harassment/hate speech. The proposed typology can be used to guide the development of risk communication plans to address each of these information-related vulnerabilities.publishedVersio
Properties of Nucleon Resonances by means of a Genetic Algorithm
We present an optimization scheme that employs a Genetic Algorithm (GA) to
determine the properties of low-lying nucleon excitations within a realistic
photo-pion production model based upon an effective Lagrangian. We show that
with this modern optimization technique it is possible to reliably assess the
parameters of the resonances and the associated error bars as well as to
identify weaknesses in the models. To illustrate the problems the optimization
process may encounter, we provide results obtained for the nucleon resonances
(1230) and (1700). The former can be easily isolated and thus
has been studied in depth, while the latter is not as well known
experimentally.Comment: 12 pages, 10 figures, 3 tables. Minor correction
Threats, Emotions, and Affective Polarization
Why do some individuals feel hostility and express bias against supporters of other political parties? Drawing on intergroup threat theory, we examine the role of emotions as a mechanism by which perceived threats against the ingroup are a source of increased affective polarization. In two survey experiments performed in the multiparty contexts of Sweden (N=505) and Germany (N=776), we manipulated intergroup threat using simulated online media, presenting participants with content related to immigration, and measured affective polarization using ratings of ingroup and outgroup supporter traits, and feeling thermometers. Compared to a control condition, the threatening content evoked fear, anxiety, and anger among participants. However, only when individuals reacted to the threatening content with anger was increased affective polarization observed, in line with research showing that anger is a high-arousal emotion related to an increased reliance on stereotypes. We conclude that individuals distance themselves from supporters of opposing political parties when they perceive a threat to their ingroup and subsequently react with anger. Overall, we contribute to the literature on affective polarization by stressing the role of emotional reactions to intergroup threat
Coherence features of the spin-aligned neutron-proton pair coupling scheme
The seniority scheme has been shown to be extremely useful for the
classification of nuclear states in semi-magic nuclei. The neutron-proton
() correlation breaks the seniority symmetry in a major way. As a result,
the corresponding wave function is a mixture of many components with different
seniority quantum numbers. In this contribution we show that the
interaction may favor a new kind of coupling in nuclei, i.e., the
so-called isoscalar spin-aligned pair mode. Shell model calculations
reveal that the ground and low-lying yrast states of the nuclei
Pd and Cd may mainly be built upon such spin-aligned pairs
each carrying the maximum angular momentum allowed by the shell
which is dominant in this nuclear region.Comment: 5 pages, 4 figues, Proceedings of the Nordic Conference on Nuclear
Physics 2011. To appear in Physica Scripta
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