L1L^1 semigroup generation for Fokker-Planck operators associated with general L\'evy driven SDEs

We prove a new generation result in $L^1$ for a large class of non-local operators with non-degenerate local terms. This class contains the operators appearing in Fokker-Planck or Kolmogorov forward equations associated with L\'evy driven SDEs, i.e. the adjoint operators of the infinitesimal generators of these SDEs. As a byproduct, we also obtain a new elliptic regularity result of independent interest. The main novelty in this paper is that we can consider very general L\'evy operators, including state-space depending coefficients with linear growth and general L\'evy measures which can be singular and have fat tails

Intensive care nurses' attitudes and behavioural intentions toward obese intensive care patients

Paper I, II, and III are not available as a part of the dissertation due to the copyright.Background: Admission of obese patients with complex health care needs to intensive care units is increasing. Caring for obese critically ill patients can be challenging for qualified intensive care nurses because of the patients’ weight, critical situation and physical challenges. Previous studies have demonstrated that some healthcare professionals hold negative attitudes toward obese patients. Obese intensive care patients may experience more stress than normal weight patients; therefore, intensive care nurses’ attitudes and the way the nurses address patient care may be important. Despite a range of studies revealing that healthcare professionals hold anti-fat attitudes toward obese patients, little is known about qualified intensive care nurses’ implicit and explicit attitudes toward obese intensive care patients and if such attitudes are associated with behavioural intentions. Furthermore, there is a current gap in knowledge about qualified intensive care nurses’ experiences of caring for obese patients in intensive care units. Aims: The overarching aim of this thesis was to understand ICU nurses’ experiences in caring for obese ICU patients, to examine the nurses’ implicit and explicit attitudes toward this group of patients and to investigate if ICU nurses’ attitudes are associated with their behavioural intentions. Designs, methods and samples: The overall design of the thesis was a ‘sequential qualitative → quantitative’ (QUAL→ quan) multimethod design. Main results: Qualified intensive care nurses experienced it as emotionally demanding caring for obese patients owing to their vulnerability, dissimilarity and physical challenges compared to normal weight patients. Simultaneously, they had implicit preferences for thin over thick people, and believed thick people were lazier, and having less willpower and being worse than thin people. The nurses endeavoured to provide good and equal care to all patients and to help the obese patients immediately. Behavioural intentions were not associated with any attitudes or stereotypes. The instruments were reliable, valid and suitable tools to measure qualified intensive care nurses’ attitudes and behavioural intention. Conclusions: This study provides new information about anti-fat attitudes and behavioural intentions among qualified intensive care nurses toward vulnerable obese intensive care patients. Despite that ICU nurses are specially trained, it appears that these nurses share the same attitudes toward obese persons as other healthcare professionals and the society in general. However, their attitudes were not associated with their behavioural intentions. These results should be acknowledged by policy makers, clinical practitioners and educators to secure optimal care for obese intensive care patients.publishedVersio

Short-term effects of bio-logging on body mass and growth of a semi-aquatic mammal, the Eurasian beaver (Castor fiber)

Bio-logging is a popular method to collect scientific data in the field of animal ecology. The presumption is that bio-logging should allow the study of animals with only minor disturbance to their natural behaviour and thereby avoid biased data. However, tagging may be stressful and may cause deleterious effects and alter natural responses or behaviour of animals. Knowledge of negative impacts associated with the tagging of animals should be assessed when possible. Bio-logging studies often lack a control group, and the adverse effects of tagging may therefore not be observable. In this study, I investigated whether glue-on tagging affected Eurasian beavers (Castor fiber) body mass and growth per day. I predicted that tagged individuals would experience reduced body mass, and externally attached tags would negatively affect beavers' growth rate per day in comparison with un-tagged beavers (control group). Thirty-one adult free-ranging beavers were tagged, and 47 un-tagged beavers were used as a control group. Linear mixed models (LMM) were used to model body mass and growth per day. Analysing differences in body mass within the tagged individuals only, showed an inconclusive result where all explanatory variables were uninformative, which indicate no substantial effect from the tag. However, analysing the tagged and un-tagged beavers combined indicated that the glue-on tag negatively affected the beavers' growth per day. This result emphasised the importance of using a control-group to reveal adverse effects that might have implications for animal welfare and sampling of biased data. Whether the adverse effects were caused by extended handling time, drag or thermoregulation are unknown. The glue-on tag likely interferes with the beaver's fur and insulation, which might be a significant factor for the decrease in beavers' growth. However, this study only investigated the short-term effect of tagged individuals. Future studies are needed to test if these effects are prolonged over time.publishedVersio

L1 semigroup generation for Fokker-Planck operators associated with general Levy driven SDEs

We prove a new generation result in L 1 for a large class of non-local operators with non-degenerate local terms. This class contains the operators appearing in Fokker-Planck or Kolmogorov forward equations associated with Lévy driven SDEs, i.e. the adjoint operators of the infinitesimal generators of these SDEs. As a byproduct, we also obtain a new elliptic regularity result of independent interest. The main novelty in this paper is that we can consider very general Lévy operators, including state-space depending coefficients with linear growth and general Lévy measures which can be singular and have fat tails.acceptedVersion© 2018. This is the authors’ accepted and refereed manuscript to the article. Locked until 1.8.2019 due to copyright restrictions

On fractional and nonlocal parabolic Mean Field Games in the whole space

We study Mean Field Games (MFGs) driven by a large class of nonlocal, fractional and anomalous diffusions in the whole space. These non-Gaussian diffusions are pure jump Lévy processes with some σ-stable like behaviour. Included are σ-stable processes and fractional Laplace diffusion operators , tempered nonsymmetric processes in Finance, spectrally one-sided processes, and sums of subelliptic operators of different orders. Our main results are existence and uniqueness of classical solutions of MFG systems with nondegenerate diffusion operators of order . We consider parabolic equations in the whole space with both local and nonlocal couplings. Our proofs use pure PDE-methods and build on ideas of Lions et al. The new ingredients are fractional heat kernel estimates, regularity results for fractional Bellman, Fokker-Planck and coupled Mean Field Game equations, and a priori bounds and compactness of (very) weak solutions of fractional Fokker-Planck equations in the whole space. Our techniques require no moment assumptions and use a weaker topology than Wasserstein.publishedVersio

Academic nurses transiton across an academic career: a qualitative study

The aim of this study was to gain a deeper understanding of nurse academics' experiences with the transition from clinical practice to academia and throughout their whole career trajectory.DesignQualitative study design.MethodsThree focus group interviews with 17 nurse academics employed at a University in Norway were conducted in May and June 2020. Data were analysed using qualitative content analysis.ResultsNurse academics experienced several diverse career transitions that continued throughout their whole career trajectory, affecting their daily life. Three interconnected themes were identified: ‘clinically confident, yet academically uncertain’, ‘balancing the academic role’ and ‘lost in academic transition’.ConclusionThis study contributes to a deeper understanding of nurse academics' experiences of transitioning into their academic role and identity. Transition was found not as separate occurrences but was described as several ongoing and concurrent processes throughout their whole career trajectory regardless of seniority level or academic experience. These transitions encompass shifts in identity, new responsibilities and increased tasks, yet often occur without adequate support. As a result, nurse academics may lack the essential skills and knowledge of the academic role.ImpactThis study provides insights into nurse academics' transition from clinical practice to academia and throughout their whole career trajectory. This is not a one-time occurrence but a continuous process that takes place throughout their entire career trajectory. This transition is embedded within a complex environment that requires careful consideration and attention. To address challenges regarding career transitions for nurse academics, universities should provide more training and preparation opportunities for all nurse academics when facing different career transitions.publishedVersio

Precise Error Bounds for Numerical Approximations of Fractional HJB Equations

We prove precise rates of convergence for monotone approximation schemes of fractional and nonlocal Hamilton–Jacobi–Bellman equations. We consider diffusion-corrected difference-quadrature schemes from the literature and new approximations based on powers of discrete Laplacians, approximations that are (formally) fractional order and second-order methods. It is well known in numerical analysis that convergence rates depend on the regularity of solutions, and here we consider cases with varying solution regularity: (i) strongly degenerate problems with Lipschitz solutions and (ii) weakly nondegenerate problems where we show that solutions have bounded fractional derivatives of order σ ∈ (1,2).Our main results are optimal error estimates with convergence rates that capture precisely both the fractional order of the schemes andthefractional regularity of the solutions. For strongly degenerate equations, these rates improve earlier results. For weakly nondegenerate problems of order greater than one, the results are new. Here we show improved rates compared to the strongly degenerate case, rates that are always better than Oh1 2 .submittedVersio

Immigration and the macroeconomy : some new empirical evidence

Proponemos un nuevo esquema de identificación VAR que nos permite separar perturbaciones migratorias de otras perturbaciones macroeconómicas. La identificación se logra imponiendo restricciones de signo a datos noruegos para el período I TR 1990-II TR 2014. La disponibilidad de series trimestrales para la inmigración neta es crucial para lograr identificación. En particular, la inmigración es una variable endógena en el modelo y puede responder al estado de la economía. Encontramos que las perturbaciones de oferta de mano de obra doméstica y las perturbaciones migratorias están bien identificadas y son los principales impulsores de la dinámica migratoria. Una perturbación exógena de inmigración reduce el desempleo (incluso entre los trabajadores nativos), tiene un pequeño efecto positivo sobre los precios y sobre las finanzas públicas, no afecta a los precios de la vivienda ni al crédito de los hogares y tiene un efecto negativo sobre la productividadWe propose a new VAR identification scheme that enables us to disentangle immigration shocks from other macroeconomic shocks. Identification is achieved by imposing sign restrictions on Norwegian data over the period 1990Q1 - 2014Q2. The availability of a quarterly series for net immigration is crucial to achieving identification. Notably, immigration is an endogenous variable in the model and can respond to the state of the economy. We find that domestic labour supply shocks and immigration shocks are well identified and are the dominant drivers of immigration dynamics. An exogenous immigration shock lowers unemployment (even among native workers), has a small positive effect on prices and on public finances, no impact on house prices and household credit, and a negative effect on productivit

The master equation for mean field game systems with fractional and nonlocal diffusions

We prove existence and uniqueness of classical solutions of the master equation for mean field game (MFG) systems with fractional and nonlocal diffusions. We cover a large class of L\'evy diffusions of order greater than one, including purely nonlocal, local, and even mixed local-nonlocal operators. In the process we prove refined well-posedness results for the MFG systems, results that include the mixed local-nonlocal case. We also show various auxiliary results on viscous Hamilton-Jacobi equations, linear parabolic equations, and linear forward-backward systems that may be of independent interest. This includes a rigorous treatment of certain equations and systems with data and solutions in the duals of H\"older spaces $C^\gamma_b$ on the whole of $\mathbb{R}^d$. We do not assume existence of any moments for the initial distributions of players. In a future work we will use the results of this paper to prove the convergence of $N$-player games to mean field games as $N\to\infty$.Comment: 59 page