| 1. |
- Afroze, Shammya, 1987, et al.
(author)
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Insight of novel layered perovskite PrSrMn2O5+δ: A neutron powder diffraction study
- 2020
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In: Materials Letters. - : Elsevier BV. - 1873-4979 .- 0167-577X. ; 261
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Journal article (peer-reviewed)abstract
- Neutron diffraction is very important to characterizing complex oxide materials, especially for the light element position and occupancy. In this study, a new layered perovskite oxide material, PrSrMn2O5+δ, was prepared by the solid-state reaction method and characterized by using X-ray and neutron powder diffraction, scanning electron microscopy and thermogravimetric analysis. X-ray diffraction data showed that the material adopted orthorhombic symmetry and Rietveld refinement of the neutron diffraction data gave accurate unit cell parameters (a = 3.8907 (1) Å, b = 3.8227 (1) Å, and c = 7.6846 (2) Å, atomic positions and space group (Pmmm)). Scanning electron microscopy showed a porous and interlinked microstructure. Thermogravimetric analysis exhibited two-stage weight losses up to 1000 °C from room temperature, indicating a good amount of oxygen losses and high material stability.
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| 2. |
- Agram, Nacira, 1987-, et al.
(author)
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On a class of reflected backward stochastic Volterra integral equations and related time-inconsistent optimal stopping problems
- 2021
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In: Systems & control letters (Print). - : Elsevier. - 0167-6911 .- 1872-7956. ; 155
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Journal article (peer-reviewed)abstract
- We introduce a class of one-dimensional continuous reflected backward stochastic Volterra integral equations driven by Brownian motion, where the reflection keeps the solution above a given stochastic process (lower obstacle). We prove existence and uniqueness by a fixed point argument and derive a comparison result. Moreover, we show how the solution of our problem is related to a time-inconsistent optimal stopping problem and derive an optimal strategy.
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| 3. |
- Jin, Shaobo, 1987-, et al.
(author)
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Standard error estimates in hierarchical generalized linear models
- 2024
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In: Computational Statistics & Data Analysis. - : Elsevier. - 0167-9473 .- 1872-7352. ; 189
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Journal article (peer-reviewed)abstract
- Hierarchical generalized linear models are often used to fit random effects models. However, attention is mostly paid to the estimation of fixed unknown parameters and inference for latent random effects. In contrast, standard error estimators receive less attention than they should be. Currently, the standard error estimators are based on various approximations, even when the mean parameters may be estimated from a higher-order approximation of the likelihood and the dispersion parameters are estimated by restricted maximum likelihood. Existing standard error estimation procedures are reviewed. A numerical illustration shows that the current standard errors are not necessarily accurate. Alternative standard errors are also proposed. In particular, a sandwich estimator that accounts for the dependence between the mean parameters and the dispersion parameters greatly improve the current standard errors.
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| 4. |
- Lu, Hongzhong, 1987, et al.
(author)
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Multiscale models quantifying yeast physiology: towards a whole-cell model
- 2022
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In: Trends in Biotechnology. - : Elsevier BV. - 0167-7799 .- 1879-3096. ; 40:3, s. 291-305
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Research review (peer-reviewed)abstract
- The yeast Saccharomyces cerevisiae is widely used as a cell factory and as an important eukaryal model organism for studying cellular physiology related to human health and disease. Yeast was also the first eukaryal organism for which a genome-scale metabolic model (GEM) was developed. In recent years there has been interest in expanding the modeling framework for yeast by incorporating enzymatic parameters and other heterogeneous cellular networks to obtain a more comprehensive description of cellular physiology. We review the latest developments in multiscale models of yeast, and illustrate how a new generation of multiscale models could significantly enhance the predictive performance and expand the applications of classical GEMs in cell factory design and basic studies of yeast physiology.
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| 5. |
- Agram, Nacira, Associate professor, 1987-, et al.
(author)
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Optimal stopping of conditional McKean–Vlasov jump diffusions
- 2024
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In: Systems & control letters (Print). - : Elsevier BV. - 0167-6911 .- 1872-7956. ; 188
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Journal article (peer-reviewed)abstract
- The purpose of this paper is to study the optimal stopping problem of conditional McKean–Vlasov (mean-field) stochastic differential equations with jumps (conditional McKean–Vlasov jump diffusions, for short). We obtain sufficient variational inequalities for a function to be the value function of such a problem and for a stopping time to be optimal.The key is that we combine the conditional McKean–Vlasov equation with the associated stochastic Fokker–Planck partial integro-differential equation for the conditional law of the state. This leads to a Markovian system which can be handled by using a version of a Dynkin formula.Our verification result is illustrated by finding the optimal time to sell in a market with common noise and jumps.
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| 6. |
- Andersson, Björn, et al.
(author)
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Fast estimation of multiple group generalized linear latent variable models for categorical observed variables
- 2023
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In: Computational Statistics & Data Analysis. - : Elsevier. - 0167-9473 .- 1872-7352. ; 182
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Journal article (peer-reviewed)abstract
- A computationally efficient method for marginal maximum likelihood estimation of multiple group generalized linear latent variable models for categorical data is introduced. The approach utilizes second-order Laplace approximations of the integrals in the likelihood function. It is demonstrated how second-order Laplace approximations can be utilized highly efficiently for generalized linear latent variable models by considering symmetries that exist for many types of model structures. In a simulation with binary observed variables and four correlated latent variables in four groups, the method has similar bias and mean squared error compared to adaptive Gauss-Hermite quadrature with five quadrature points while substantially improving computational efficiency. An empirical example from a large-scale educational assessment illustrates the accuracy and computational efficiency of the method when compared against adaptive Gauss-Hermite quadrature with three, five, and 13 quadrature points.
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| 7. |
- Barth, Henrik, 1971-, et al.
(author)
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Refugee entrepreneurship in the agri-food industry : The Swedish experience
- 2021
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In: Journal of Rural Studies. - Oxford : Elsevier. - 0743-0167 .- 1873-1392. ; 86, s. 189-197
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Journal article (peer-reviewed)abstract
- Following the recent mass migration of refugees to the European Union in 2015 and 2016, many EU countries took significant steps aimed at improving the socio-economic integration of the refugees. This study examines refugee entrepreneurship in rural areas in Sweden as evidenced in the agri-food industry. Entrepreneurship is often considered a sustainable activity that can promote refugees' economic independence and social integration. The rural setting offers promising employment opportunities for refugees with agricultural backgrounds or interest. Qualitative research methodology, based on 25 in-depth, semi-structured interviews with refugees, is used to examine refugee entrepreneurs’ experiences in the various phases of the entrepreneurial process, from start-up and growth to success/exit. The study found that refugee entrepreneurs are motivated and challenged variously as they start and operate their entrepreneurial activities. For example, they are motivated by the discovery of niche markets, previous entrepreneurial experience, and the availability of family and government support. Challenges include legislative hurdles, management and technical problems, and insufficient financial and other support. Factors both within and outside their control influence the survival of their entrepreneurship. © 2021
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| 8. |
- Chojnacki, W., et al.
(author)
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The equivalence of two definitions of compatible homography matrices
- 2020
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In: Pattern Recognition Letters. - : Elsevier BV. - 0167-8655 .- 1872-7344. ; 135, s. 38-43
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Journal article (peer-reviewed)abstract
- In many computer vision applications, one acquires images of planar surfaces from two different vantage points. One can use a projective transformation to map pixel coordinates associated with a particular planar surface from one image to another. The transformation, called a homography, can be represented by a unique, to within a scale factor, 3 × 3 matrix. One requires a different homography matrix, scale differences apart, for each planar surface whose two images one wants to relate. However, a collection of homography matrices forms a valid set only if the matrices satisfy consistency constraints implied by the rigidity of the motion and the scene. We explore what it means for a set of homography matrices to be compatible and show that two seemingly disparate definitions are in fact equivalent. Our insight lays the theoretical foundations upon which the derivation of various sets of homography consistency constraints can proceed. © 2020 Elsevier B.V.
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| 9. |
- Engström, Per, 1974-, et al.
(author)
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Loss aversion and indifference to tax rates: Evidence from tax filing data
- 2022
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In: Journal of Economic Behavior & Organization. - : Elsevier BV. - 0167-2681 .- 1879-1751. ; 200, s. 287-311
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Journal article (peer-reviewed)abstract
- A fundamental tenet of economics is that agents respond to incentives. When filing their tax returns, Swedish taxpayers get information about whether they are below or above a salient tax kink, information that could affect tax-filing behavior. Ceteris paribus, rational taxpayers would be more likely to claim deductions when facing a higher marginal tax rate. They also get informed whether they can expect a tax refund or have taxes due. This information would be of no importance to rational individuals, but a loss averse taxpayer would be more likely to claim deductions if having taxes due than if expecting a refund. We study the probability of claiming deductions in an RDK framework using register data on the universe of Swedish taxpayers over an eight-year period. We find a strong causal effect of taxes due, while the response to the marginal tax kink is insignificant. The results are similar for inexperienced (young) and experienced (old) taxpayers. Hence, loss aversion is much more decisive than standard economic incentives in predicting deduction behavior. (C) 2022 The Authors. Published by Elsevier B.V.
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| 10. |
- Flink, Ida K., 1980-, et al.
(author)
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Expecting the uncertain : The applicability of the intolerance of uncertainty model on fear of childbirth
- 2023
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In: Journal of Psychosomatic Obstetrics and Gynaecology. - : Taylor & Francis. - 0167-482X .- 1743-8942. ; 44:1
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Journal article (peer-reviewed)abstract
- A considerable number of pregnant women experience fear of childbirth (FOC), characterized by worries and fear of the unpredictable. Despite this, the psychological processes in FOC have received notably little attention. The aim of this study was to advance the understanding by exploring the applicability of the Intolerance of Uncertainty (IU) model on FOC. Anonymous data was collected in a sample of pregnant women (N = 357) with varying levels of FOC. Analyses supported the associations between FOC and all proposed psychological processes: IU, negative problem orientation, positive beliefs about worry and avoidance of inner experiences. The exploration of potential mediators of the relation between IU and FOC revealed that, of the three processes from the model, only positive beliefs about worry were a mediator, and more specifically, a partial mediator between IU and FOC. These findings add to the theoretical understanding of FOC, by indicating that the role of IU may be similar to other conditions inflicted by worry and anxiety, which may inform treatment development. © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.
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