Supercoherent States, Super K\"ahler Geometry and Geometric Quantization

Generalized coherent states provide a means of connecting square integrable representations of a semi-simple Lie group with the symplectic geometry of some of its homogeneous spaces. In the first part of the present work this point of view is extended to the supersymmetric context, through the study of the OSp(2/2) coherent states. These are explicitly constructed starting from the known abstract typical and atypical representations of osp(2/2). Their underlying geometries turn out to be those of supersymplectic OSp(2/2) homogeneous spaces. Moment maps identifying the latter with coadjoint orbits of OSp(2/2) are exhibited via Berezin's symbols. When considered within Rothstein's general paradigm, these results lead to a natural general definition of a super K\"ahler supermanifold, the supergeometry of which is determined in terms of the usual geometry of holomorphic Hermitian vector bundles over K\"ahler manifolds. In particular, the supergeometry of the above orbits is interpreted in terms of the geometry of Einstein-Hermitian vector bundles. In the second part, an extension of the full geometric quantization procedure is applied to the same coadjoint orbits. Thanks to the super K\"ahler character of the latter, this procedure leads to explicit super unitary irreducible representations of OSp(2/2) in super Hilbert spaces of $L^2$ superholomorphic sections of prequantum bundles of the Kostant type. This work lays the foundations of a program aimed at classifying Lie supergroups' coadjoint orbits and their associated irreducible representations, ultimately leading to harmonic superanalysis. For this purpose a set of consistent conventions is exhibited.Comment: 53 pages, AMS-LaTeX (or LaTeX+AMSfonts

Modeling the Subsurface Structure of Sunspots

While sunspots are easily observed at the solar surface, determining their subsurface structure is not trivial. There are two main hypotheses for the subsurface structure of sunspots: the monolithic model and the cluster model. Local helioseismology is the only means by which we can investigate subphotospheric structure. However, as current linear inversion techniques do not yet allow helioseismology to probe the internal structure with sufficient confidence to distinguish between the monolith and cluster models, the development of physically realistic sunspot models are a priority for helioseismologists. This is because they are not only important indicators of the variety of physical effects that may influence helioseismic inferences in active regions, but they also enable detailed assessments of the validity of helioseismic interpretations through numerical forward modeling. In this paper, we provide a critical review of the existing sunspot models and an overview of numerical methods employed to model wave propagation through model sunspots. We then carry out an helioseismic analysis of the sunspot in Active Region 9787 and address the serious inconsistencies uncovered by \citeauthor{gizonetal2009}~(\citeyear{gizonetal2009,gizonetal2009a}). We find that this sunspot is most probably associated with a shallow, positive wave-speed perturbation (unlike the traditional two-layer model) and that travel-time measurements are consistent with a horizontal outflow in the surrounding moat.Comment: 73 pages, 19 figures, accepted by Solar Physic

Small-scale solar magnetic fields

As we resolve ever smaller structures in the solar atmosphere, it has become clear that magnetism is an important component of those small structures. Small-scale magnetism holds the key to many poorly understood facets of solar magnetism on all scales, such as the existence of a local dynamo, chromospheric heating, and flux emergence, to name a few. Here, we review our knowledge of small-scale photospheric fields, with particular emphasis on quiet-sun field, and discuss the implications of several results obtained recently using new instruments, as well as future prospects in this field of research.Comment: 43 pages, 18 figure

Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review

Acromegaly at diagnosis in 3173 patients from the Liège Acromegaly Survey (LAS) Database

Acromegaly is a rare disorder caused by chronic growth hormone (GH) hypersecretion. While diagnostic and therapeutic methods have advanced, little information exists on trends in acromegaly characteristics over time. The Liège Acromegaly Survey (LAS) Database, a relational database, is designed to assess the profile of acromegaly patients at diagnosis and during long-term follow-up at multiple treatment centers. The following results were obtained at diagnosis. The study population consisted of 3173 acromegaly patients from ten countries; 54.5% were female. Males were significantly younger at diagnosis than females (43.5 vs 46.4 years; P 3100 patients is the largest international acromegaly database and shows clinically relevant trends in the characteristics of acromegaly at diagnosis

Medical nutrition therapy during intensive remission-induction treatment and hematopoietic stem cell transplantation in acute myeloid leukemia patients:Hematologists’ experiences and perspectives

Background & aims: The European Societies for Clinical Nutrition and Metabolism (ESPEN) and Blood and Marrow Transplantation (EBMT) recommend enteral nutrition (EN) as the first-choice medical nutrition therapy in acute myeloid leukemia (AML) patients undergoing intensive treatments, including high-dose remission-induction chemotherapy and hematopoietic stem cell transplantation (HSCT). However, parenteral nutrition (PN) remains the preferred method of nutrition support in current clinical practice. The aim of this qualitative study was to gain insight into hematologists’ experiences and perspectives regarding the choice and ESPEN/EBMT recommendations on EN versus PN. Methods: Online semi-structured interviews were conducted with one hematologist from each of the 21 hospitals offering intensive AML treatments in the Netherlands, using Microsoft Teams. Interviews were audio-recorded, transcribed verbatim and thematically analyzed using Atlas. ti. One hundred nineteen hematologists working in the same hospitals were invited to complete a short online questionnaire survey (SurveyMonkey®) regarding their knowledge and opinion on the ESPEN/EBMT guidelines recommending EN over PN during intensive AML treatments. The results of this survey are presented in a descriptive way. Results: Fifty-nine hematologists participated in this study (42% overall response rate), of which 21 in the semi-structured interviews (response rate 100%) and 38 in the online survey (response rate 32%). Hematologists considered medical nutrition therapy important for prevention and treatment of malnutrition and associated adverse outcomes in AML patients undergoing intensive remission-induction treatment and HSCT. However, opposed to the ESPEN/EBMT guidelines, the vast majority of hematologists were hesitant or reluctant to use EN instead of PN as the first-choice medical nutrition therapy in these patients. The most frequently cited barriers to use EN were the expected low feasibility and tolerance of EN, feeding tube-related discomfort and bleeding risk, and patient refusal. Other barriers to follow the guidelines on EN were related to personal factors, including hematologists’ knowledge (lack of awareness and familiarity) and attitude (lack of agreement, outcome expectancy, experience, success, motivation, and learning culture), guideline-related factors (lack of evidence and applicability), and external factors (lack of collaboration and resources). Facilitators included strategies for nutrition education and dissemination of nutritional guidelines, interprofessional and patient collaboration, availability of feeding tubes that can be inserted without endoscopy and stronger scientific evidence. Conclusions: Hematologists recognized the importance of medical nutrition therapy for reducing malnutrition and related negative outcomes during intensive AML treatments. However, contrary to the ESPEN/EBMT guidelines, they preferred PN instead of EN as the medical nutrition therapy of first choice. To reduce compliance barriers, interventions should focus on improving hematologists’ knowledge of medical nutrition therapy and dietary guidelines, enhancing success rates of EN by adequately triaging patients eligible for EN and inserting duodenal feeding tubes using an electromagnetic sensing device without endoscopy, developing decision aids and multidisciplinary guidelines and care pathways. Furthermore, future trials should focus on the feasibility and benefits of EN versus PN both during remission-induction treatment and HSCT