The C∗C^*-algebra of the quantum symplectic sphere

The faithful irreducible $*$-representations of the $C^*$-algebra of the quantum symplectic sphere $S_q^{4n-1}, n\geq 2$, have been investigated by D'Andrea and Landi. They proved that the first $n-1$ generators are all zero inside $C^*(S_q^{4n-1})$, for $n\geq 2$. The result is a generalisation of the case where $n=2$, which was shown by Mikkelsen and Szyma\'nski. We will show that $C^*(S_q^{4n-1}), n\geq 2$ is isomorphic to a graph $C^*$-algebra. From here it follows that $C^*(S_q^{4n-1})$ is isomorphic to the quantum $(2(n+1)-1)$-sphere by Vaksman and Soibelman

A vector space basis of the quantum symplectic sphere

We give a candidate of a vector space basis for the algebra $\mathcal{O}(S_q^{4n-1})$ of the quantum symplectic sphere for every $n\geq 1$. The construction follows by a non-trivial application of the Diamond Lemma. The conjecture is supported by computer experiments for $n=1,2,...,8$. The work is motivated by a result of Landi and D'Andrea, who proved that the first $n-1$ generators of the $C^*$-algebra $C(S_q^{(4n-1)}), n\geq 2$ are zero. By finding a vector space basis, we can conclude that these generators are different from zero in the corresponding algebra $\mathcal{O}(S_q^{4n-1})$

The Quantum Twistor Bundle

We investigate the quantum twistor bundle constructed as a $U(1)$-quotient of the quantum instanton bundle of Bonechi, Ciccoli and Tarlini. It is an example of a locally trivial noncommutative bundle fulfilling conditions of the framework recently proposed by Brzezi\'nski and Szyma\'nski. In particular, we give a detailed description of the corresponding $C^*$-algebra of 'continuous functions' on its noncommutative total space. Furthermore, we analyse a different construction of a quantum instanton bundle due to Landi, Pagani and Reina, find a basis of its polynomial algebra and discover an intriguing and unexpected feature of its enveloping $C^*$-algebra

Social relations and healthcare utilisation among middle-aged and older people:study protocol for an implementation and register-based study in Denmark

Abstract Background While previous research establishes an association between social relations, health and use of healthcare services among older people, how to implement this knowledge in real-life settings has received much less attention. This study will explore the relationship between social relations, health and use of healthcare services in a Danish mid-life population sample. In addition, the study will explore individual and contextual factors affecting the implementation of a group-based life story intervention aimed at establishing and strengthening social relations among older people at nursing homes in Denmark. Methods/design A combined quantitative register-based approach and a qualitative implementation approach will be applied in this study. First, we will quantitatively analyse the relationship between social relations, health status and use of healthcare services among middle-aged people in Denmark by linking survey data on social relations, loneliness, self-perceived health and disease status from the Copenhagen Aging and Midlife Biobank (CAMB) (n = 7191) with national registries through the Public Health Database on use of healthcare services and demographic and socioeconomic factors. Second, we will qualitatively analyse individual and contextual factors affecting the implementation process of the group-based life story intervention based on semi-structured interviews (n = 16), observations and field notes with and among intervention stakeholders, i.e., participants and group leaders facilitating the intervention. Discussion The results of this study are expected to improve knowledge about mechanisms through which social relations are associated with health status and use of healthcare services and to inform the implementation of future interventions targeting social relations among older people at nursing homes. Trial registration The study has been registered and approved by the Danish Data Protection Agency. Seperate approvals have been attained for the qualitative data (Approval No. SUND-2016-08), and for the quantitative data in the CAMB database which has also received approval from the local ethical committee (approval No.H-A-2008-126 and No. 2013–41-1814, respectively)

On Conjugacy of Subalgebras of Graph C*-Algebras

The problem of inner vs outer conjugacy of subalgebras of certain graph C*-algebras is investigated. For a large class of finite graphs E, we show that whenever $\alpha$ is a vertex-fixing quasi-free automorphism of the corresponding graph C*-algebra C*(E) such that \alpha(\D_E)\neq\D_E, where \D_E is the canonical MASA in C*(E), then \alpha(\D_E)\neq w\D_E w^* for all unitaries w\in C*(E). That is, the two MASAs \D_E and \alpha(\D_E) of C*(E) are outer but not inner conjugate. Passing to an isomorphic C*-algebra by changing the underlying graph makes this result applicable to certain non quasi-free automorphisms as well. For the Cuntz algebras O_n, we find a criterion which guarantees that a polynomial automorphism moves the canonical UHF subalgebra to a non-inner conjugate UHF subalgebra. The criterion is phrased in terms of rescaling of trace on diagonal projections.Comment: arXiv admin note: substantial text overlap with arXiv:1604.0710

Social Interventions Targeting Social Relations Among Older People at Nursing Homes:A Qualitative Synthesized Systematic Review

Social relations are part of the complex set of factors affecting health and well-being in old age. This systematic review seeks to uncover whether social interventions have an effect on social and health-related measures among nursing home residents. The authors screened PubMed, Scopus, and PsycINFO for relevant peer-reviewed literature. Interventions were included if (1) they focused primarily on social relations or related terms such as loneliness, social support, social isolation, social network, or being involuntarily alone either as the base theory of the intervention or as an outcome measure of the intervention; (2) they were implemented at nursing homes (or similar setting); (3) they had a narrative activity as its core (as opposed to dancing, gardening or other physical activity); (4) their participants met either physically or nonphysically, ie, via video-conference or the like; and if (5) they targeted residents at a nursing home. The authors systematically appraised the quality of the final selection of studies using the Mixed Methods Assessments Tool (MMAT) version 2011 and did a qualitative synthesis of the final study selection. A total of 10 studies were included. Reminiscence therapy was the most common intervention. Studies also included video-conference, cognitive, and support group interventions. All studies found the social interventions brought about positive trends on either/or the social and health-related measures included. Despite limited and very diverse evidence, our systematic review indicated a positive social and health-related potential of social interventions for older people living in nursing homes or similar institutions

Report of the NAMMCO-ICES Workshop on Seal Modelling (WKSEALS 2020)

To support sustainable management of apex predator populations, it is important to estimate population size and understand the drivers of population trends to anticipate the consequences of human decisions. Robust population models are needed, which must be based on realistic biological principles and validated with the best available data. A team of international experts reviewed age-structured models of North Atlantic pinniped populations, including Grey seal (Halichoerus grypus), Harp seal (Pagophilus groenlandicus), and Hooded seal (Cystophora cristata). Statistical methods used to fit such models to data were compared and contrasted. Differences in biological assumptions and model equations were driven by the data available from separate studies, including observation methodology and pre-processing. Counts of pups during the breeding season were used in all models, with additional counts of adults and juveniles available in some. The regularity and frequency of data collection, including survey counts and vital rate estimates, varied. Important differences between the models concerned the nature and causes of variation in vital rates (age-dependent survival and fecundity). Parameterisation of age at maturity was detailed and time-dependent in some models and simplified in others. Methods for estimation of model parameters were reviewed and compared. They included Bayesian and maximum likelihood (ML) approaches, implemented via bespoke coding in C, C++, TMB or JAGS. Comparative model runs suggested that as expected, ML-based implementations were rapid and computationally efficient, while Bayesian approaches, which used MCMC or sequential importance sampling, required longer for inference. For grey seal populations in the Netherlands, where preliminary ML-based TMB results were compared with the outputs of a Bayesian JAGS implementation, some differences in parameter estimates were apparent. For these seal populations, further investigations are recommended to explore differences that might result from the modelling framework and model-fitting methodology, and their importance for inference and management advice. The group recommended building on the success of this workshop via continued collaboration with ICES and NAMMCO assessment groups, as well as other experts in the marine mammal modelling community. Specifically, for Northeast Atlantic harp and hooded seal populations, the workshop represents the initial step towards a full ICES benchmark process aimed at revising and evaluating new assessment models.Publisher PDFPeer reviewe

Growth hormone deficiency in adult survivors of childhood brain tumors treated with radiation

Objective: Growth hormone deficiency (GHD) is the most common endocrine la te effect in irradiated survivors of childhood brain tumors. This study a imed to determine the prevalence of GHD in adults treated with proton or photon irradiation for a brain tumor in childhood and to detect undiagnosed GHD. Design: This study is a cross-sectional study. Methods: We investigated GHD in 5-year survivors from two health region s in Denmark treated for childhood brain tumors with cranial or craniospinal irradiation in the period 1997–2015. Medical charts were reviewed for endocrinological and other health data. Survivors without a growth hormone (GH) test at final height wer e invited to a GH stimulation test. Results: Totally 41 (22 females) survivors with a median age of 21.7 ye ars (range: 15.1– 33.8 years) at follow-up and 14.8 years (range: 5.1–23.4 years) since diagnosis were included; 11 were treated with proton and 30 with photon irradiation; 18 of 21 survivors were previously found to have GHD; 16 of 20 survivors with no G H test at final height were tested, 8 (50 %) had GHD. In total, 26 of 41 patients (63% ) had GHD. Insulin-like growth factor-1 (IGF-1) is associated poorly with the insulin t olerance test (ITT). Conclusion: This study identified a high prevalence of undiagnosed GHD in s urvivors with no GH test at final height. The results stress the importance of screening for GHD at final height in survivors of childhood brain tumors with prior exposure to cranial irradiation, irrespective of radiation modality and IGF-1. Significance statement: This cross-sectional study reports a prevalence of 63% of GHD in irradiated childhood brain tumor survivors. Furthermore, the study identified a considerable number of long-term survivors without a GH test at final height, of whom, 50% subsequently were shown to have undiagnosed GHD. Additional ly, this study confirmed that a normal serum IGF-1 measurement cannot exclude t he diagnosis of GHD in irradiated survivors. This illustrates the need for improvements in the diagnostic approach to GHD after reaching final height in childhood brain t umor survivors at risk of GHD. In summary, our study stresses the need for GHD testing in all adult survivors treated with cranial irradiation for a brain tumor in childhood irrespe ctive of radiation modality