| 32621. |
- Larsman, Pernilla, 1976, et al.
(författare)
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Psychosocial work conditions, perceived stress, perceived muscular tension, and neck/shoulder symptoms among medical secretaries
- 2013
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 1432-1246 .- 0340-0131. ; 86:1, s. 57-63
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Tidskriftsartikel (refereegranskat)abstract
- Purpose Unfavorable psychosocial working conditions are hypothesized to lead to perceived stress, which, in turn, can be related to an increased risk of development of neck/shoulder symptoms through increased and sustained muscle activation. The aim of the present study was to test this hypothesized process model among medical secretaries, a female-dominated profession characterized by a high amount of visual display unit use and a high prevalence of neck/shoulder symptoms. Methods In this cross-sectional study, a questionnaire survey was conducted among medical secretaries (n = 200). The proposed process model was tested using a path model framework. Results The results indicate that high work demands were related to high perceived stress, which in turn was related to a high perceived muscle tension and neck/shoulder symptoms. Low influence at work was not related to perceived stress, but was directly related to a high perceived muscle tension. Conclusions In general, these cross-sectional results lend tentative support for the hypothesis that adverse psychosocial work conditions (high work demands) may contribute to the development of neck/shoulder symptoms through the mechanism of stress-induced sustained muscular activation. This process model needs to be further tested in longitudinal studies.
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| 32622. |
- Larsman, Pernilla, 1976, et al.
(författare)
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Role modeling of safety-leadership behaviors in the construction industry: A two-wave longitudinal study
- 2024
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Ingår i: Work: A journal of Prevention, Assesment and rehabilitation. - 1051-9815. ; 77:2, s. 523-531
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The construction industry is heavily affected by occupational accidents, and it is important to investigate how leadership behaviors promoting safety on construction sites are fostered among construction-site managers. OBJECTIVE: The overall aim of this study was to investigate how safety-leadership behaviors can be developed in the construction industry, specifically focusing on managerial role modeling. METHODS: A two-wave longitudinal cohort study with approximately four months between measurement occasions was conducted among construction-site supervisors in Sweden (n =51). Supervisors’ ratings of their site managers’ and their own generic and safety-specific contingent reward (CR) leadership behaviors were obtained by means of questionnaires. Cross-lagged panel models were tested within a path model framework to test the hypothesis that site managers’ leadership behaviors prospectively influence supervisors’ leadership behaviors. RESULTS: Site managers’ CR behaviors prospectively influenced supervisors’ CR behaviors, both generic CR behaviors (β=0.29, p =0.01) and safety-specific CR behaviors (β=0.22, p =0.04). For safety-specific CR behaviors, a reversed effect (β=0.26, p =0.03) was also found, implying that supervisors’ behaviors prospectively influenced site managers’ behaviors. CONCLUSION: Site managers act as role models for supervisors when it comes to developing safety-leadership behaviors on construction sites. The results also indicate that site managers are influenced by their subordinate supervisors’ safety-leadership behaviors. Hence, there seems to be reciprocal interaction between site managers and supervisors in which they influence each other and together shape safety-leadership practices at their construction sites.
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| 32623. |
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| 32624. |
- Larsman, Pernilla, 1976, et al.
(författare)
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Work related perceived stress and muscle activity during standardized computer work among female computer users
- 2009
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Ingår i: Work : A journal of Prevention, Assesment and rehabilitation. - 1051-9815. ; 32:2, s. 189-199
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Tidskriftsartikel (refereegranskat)abstract
- The current study investigated the associations between work-related perceived stress and surface electromyographic (sEMG) parameters (muscle activity and muscle rest) during standardized simulated computer work (typing, editing, precision, and Stroop tasks). It was part of the European case-control study, NEW (Neuromuscular assessment in the Elderly Worker). The present cross-sectional study was based on a questionnaire survey and sEMG measurements among Danish and Swedish female computer users aged 45 or older (n=49). The results show associations between work-related perceived stress and trapezius muscle activity and rest during standardized simulated computer work, and provide partial empirical support for the hypothesized pathway of stress induced muscle activity in the association between an adverse psychosocial work environment and musculoskeletal symptoms in the neck and shoulder.
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| 32625. |
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| 32626. |
- Larson, Kristine, et al.
(författare)
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Coastal Sea Level Measurements Using a Single Geodetic GPS Receiver
- 2013
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Ingår i: Advances in Space Research. - : Elsevier BV. - 1879-1948 .- 0273-1177. ; 51:8, s. 1301-1310
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a method to derive local sea level variations using data from a single geodetic-quality Global Navigation Satellite System (GNSS) receiver using GPS (Global Positioning System) signals. This method is based on multipath theory for specular reflections and the use of Signal-to-Noise Ratio (SNR) data. The technique could be valuable for altimeter calibration and validation. Data from two test sites, a dedicated GPS tide gauge at the Onsala Space Observatory (OSO) in Sweden and the Friday Harbor GPS site of the EarthScope Plate Boundary Observatory (PBO) in USA, are analyzed. The sea level results are compared to independently observed sea level data from nearby and in situ tide gauges. For OSO, the Root-Mean-Square (RMS) agreement is better than 5 cm, while it is on the order of 10 cm for Friday Harbor. The correlation coefficients are better than 0.97 for both sites. For OSO, the SNR-based results are also compared with results from a geodetic analysis of GPS data of a two receivers/antennae tide gauge installation. The SNR-based analysis results in a slightly worse RMS agreement with respect to the independent tide gauge data than the geodetic analysis (4.8 cm and 4.0 cm, respectively). However, it provides results even for rough sea surface conditions when the two receivers/antennae installation no longer records the necessary data for a geodetic analysis.
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| 32627. |
- Larson, Mats G., et al.
(författare)
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Space-time CutFEM on overlapping meshes I: simple continuous mesh motion
- 2024
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Ingår i: NUMERISCHE MATHEMATIK. - : Springer Science+Business Media B.V.. - 0029-599X .- 0945-3245. ; 156, s. 1015-1054
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Tidskriftsartikel (refereegranskat)abstract
- We present a cut finite element method for the heat equation on two overlapping meshes: a stationary background mesh and an overlapping mesh that moves around inside/"on top" of it. Here the overlapping mesh is prescribed by a simple continuous motion, meaning that its location as a function of time is continuous and piecewise linear. For the discrete function space, we use continuous Galerkin in space and discontinuous Galerkin in time, with the addition of a discontinuity on the boundary between the two meshes. The finite element formulation is based on Nitsche's method and also includes an integral term over the space-time boundary between the two meshes that mimics the standard discontinuous Galerkin time-jump term. The simple continuous mesh motion results in a space-time discretization for which standard analysis methodologies either fail or are unsuitable. We therefore employ what seems to be a relatively uncommon energy analysis framework for finite element methods for parabolic problems that is general and robust enough to be applicable to the current setting. The energy analysis consists of a stability estimate that is slightly stronger than the standard basic one and an a priori error estimate that is of optimal order with respect to both time step and mesh size. We also present numerical results for a problem in one spatial dimension that verify the analytic error convergence orders.
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| 32628. |
- Larson, Simon
(författare)
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A bound for the perimeter of inner parallel bodies
- 2016
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Ingår i: Journal of Functional Analysis. - : Academic Press. - 0022-1236 .- 1096-0783. ; 271:3, s. 610-619
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Tidskriftsartikel (refereegranskat)abstract
- We provide a sharp lower bound for the perimeter of the inner parallel sets of a convex body Ω. The bound depends only on the perimeter and inradius r of the original body and states that. |∂Ωt|≥(1-tr)+n-1|∂Ω|. In particular the bound is independent of any regularity properties of ∂Ω. As a by-product of the proof we establish precise conditions for equality. The proof, which is straightforward, is based on the construction of an extremal set for a certain optimization problem and the use of basic properties of mixed volumes.
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| 32629. |
- Larson, Simon, 1990
(författare)
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A sharp multidimensional Hermite-Hadamard inequality
- 2022
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Ingår i: International Mathematics Research Notices. - : Oxford University Press (OUP). - 1073-7928 .- 1687-0247. ; 2022:2, s. 1297-1312
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Tidskriftsartikel (refereegranskat)abstract
- Let $\Omega \subset {\mathbb{R}}^d $, $d \geq 2$, be a bounded convex domain and $f\colon \Omega \to{\mathbb{R}}$ be a non-negative subharmonic function. In this paper, we prove the inequality $$\begin{equation*} \frac{1}{|\Omega|}\int_{\Omega} f(x)\, \textrm{d}x \leq \frac{d}{|\partial\Omega|}\int_{\partial\Omega} f(x)\, \textrm{d}\sigma(x)\,. \end{equation*}$$Equivalently, the result can be stated as a bound for the gradient of the Saint Venant torsion function. Specifically, if $\Omega \subset{\mathbb{R}}^d$ is a bounded convex domain and $u$ is the solution of $-\Delta u =1$ with homogeneous Dirichlet boundary conditions, then $$\begin{equation*} \|\nabla u\|_{L^\infty(\Omega)} < d\frac{|\Omega|}{|\partial\Omega|}\,. \end{equation*}$$Moreover, both inequalities are sharp in the sense that if the constant $d$ is replaced by something smaller there exist convex domains for which the inequalities fail. This improves upon the recent result that the optimal constant is bounded from above by $d^{3/2}$ due to Beck et al. [2].
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| 32630. |
- Larson, Simon
(författare)
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Asymptotic shape optimization for Riesz means of the Dirichlet Laplacian over convex domains
- 2019
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Ingår i: Journal of Spectral Theory. - : EUROPEAN MATHEMATICAL SOC. - 1664-039X .- 1664-0403. ; 9:3, s. 857-895
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Tidskriftsartikel (refereegranskat)abstract
- For Omega subset of R-n, a convex and bounded domain, we study the spectrum of -Delta(Omega) the Dirichlet Laplacian on Omega. For Lambda >= 0 and gamma >= 0 let Omega(Lambda,gamma)(A) denote any extremal set of the shape optimization problem sup {Tr(-Delta(Omega) - Lambda)(gamma) : Omega is an element of .A, vertical bar Omega vertical bar = 1}, where A is an admissible family of convex domains in R-n. If gamma >= 1 and (1) and {Lambda(j)}(j >= 1) is a positive sequence tending to infinity we prove that {Omega Lambda j , gamma(A)}(j >= 1) is a bounded sequence, and hence contains a convergent subsequence. Under an additional assumption on A we characterize the possible limits of such subsequences asminimizers of the perimeter among domains in A of unit measure. For instance if A is the set of all convex polygons with no more than m faces, then Omega(Lambda,gamma) converges, up to rotation and translation, to the regular m-gon.
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