ORCID Profile
0000-0002-5221-5877
Current Organisation
University of Western Australia
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Publisher: American Institute of Mathematical Sciences (AIMS)
Date: 2022
Publisher: Uniwersytet Mikolaja Kopernika/Nicolaus Copernicus University
Date: 12-06-2022
Publisher: Springer Science and Business Media LLC
Date: 07-07-2022
DOI: 10.1007/S00420-022-01904-1
Abstract: To evaluate the effects of a workplace fatigue management programme called MARIKERJA on reducing fatigue among manufacturing shift workers in Indonesia. A quasi-experimental pre- and post-test study was conducted among 116 shift workers (58 in the intervention group and 58 in the control group). The MARIKERJA programme was delivered to the intervention group for 12 weeks. Meanwhile, the control groups received the MARIKERJA intervention only at the end of the study period. Fatigue levels were measured using the Fatigue Severity Scale (FSS) in weeks 6 and 12 of the intervention. Data were analysed using a t test and a general linear model repeated measures procedure. There were significant differences in fatigue scores between the control and intervention groups after the MARIKERJA intervention in week 6 (40.07 ± 8.89 vs. 27.12 ± 11.67 p < 0.001) and week 12 (38.22 ± 9.28 vs. 17.53 ± 6.54 p < 0.001). The MARIKERJA intervention effectively reduced fatigue levels by up to 37.3% (R The MARIKERJA intervention effectively reduces fatigue among manufacturing shift workers.
Publisher: Elsevier BV
Date: 03-2023
Publisher: Elsevier BV
Date: 06-2023
Publisher: Walter de Gruyter GmbH
Date: 14-03-2021
Abstract: The aim of this paper is investigating the existence of one or more weak solutions of the coupled quasilinear elliptic system of gradient type \textup{(P)} { - ( A ( x , u ) | ∇ u | p 1 - 2 ∇ u ) + 1 p 1 A u ( x , u ) | ∇ u | p 1 = G u ( x , u , v ) in Ω , - ( B ( x , v ) | ∇ v | p 2 - 2 ∇ v ) + 1 p 2 B v ( x , v ) | ∇ v | p 2 = G v ( x , u , v ) in Ω , u = v = 0 on ∂ Ω , \left\{\begin{aligned} \displaystyle-\operatorname{ }(A(x,u)|\nabla u|^{p_{1% }-2}\nabla u)+\frac{1}{p_{1}}A_{u}(x,u)|\nabla u|^{p_{1}}& \displaystyle=G_{u}(% x,u,v)& & \displaystyle\phantom{}\text{in~{}${\Omega}$,}\\ \displaystyle-\operatorname{ }(B(x,v)|\nabla v|^{p_{2}-2}\nabla v)+\frac{1}{% p_{2}}B_{v}(x,v)|\nabla v|^{p_{2}}& \displaystyle=G_{v}(x,u,v)& & \displaystyle% \phantom{}\text{in~{}${\Omega}$,}\\ \displaystyle u=v& \displaystyle=0& & \displaystyle\phantom{}\text{on ${\partial% \Omega}$,}\end{aligned}\right. where Ω ⊂ ℝ N {\Omega\subset\mathbb{R}^{N}} is an open bounded domain, p 1 {p_{1}} , p 2 1 {p_{2} } and A ( x , u ) {A(x,u)} , B ( x , v ) {B(x,v)} are 𝒞 1 {\mathcal{C}^{1}} -Carathéodory functions on Ω × ℝ {\Omega\times\mathbb{R}} with partial derivatives A u ( x , u ) {A_{u}(x,u)} , respectively B v ( x , v ) {B_{v}(x,v)} , while G u ( x , u , v ) {G_{u}(x,u,v)} , G v ( x , u , v ) {G_{v}(x,u,v)} are given Carathéodory maps defined on Ω × ℝ × ℝ {\Omega\times\mathbb{R}\times\mathbb{R}} which are partial derivatives of a function G ( x , u , v ) {G(x,u,v)} . We prove that, even if the coefficients make the variational approach more difficult, under suitable hypotheses functional 𝒥 {{\mathcal{J}}} , related to problem (P), admits at least one critical point in the “right” Banach space X . Moreover, if 𝒥 {{\mathcal{J}}} is even, then (P) has infinitely many weak bounded solutions. The proof, which exploits the interaction between two different norms, is based on a weak version of the Cerami–Palais–Smale condition, a “good” decomposition of the Banach space X and suitable generalizations of the Ambrosetti–Rabinowitz Mountain Pass Theorems.
Publisher: Springer Science and Business Media LLC
Date: 17-04-2023
DOI: 10.1007/S00033-023-01977-Z
Abstract: The first part of this paper concern with the study of the Lorentz force equation $$\begin{aligned} \left( \frac{q'}{\sqrt{1-|q'|^2}}\right) '= \overrightarrow{E}(t,q)+q'\times \overrightarrow{B}(t,q) \end{aligned}$$ q ′ 1 - | q ′ | 2 ′ = E → ( t , q ) + q ′ × B → ( t , q ) in the relevant physical configuration where the electric field $$\overrightarrow{E}$$ E → has a singularity in zero. By using Szulkin’s critical point theory, we prove the existence of T -periodic solutions provided that T and the electric and magnetic fields interact properly. In the last part, we employ both a variational and a topological argument to prove that the scalar relativistic pendulum-type equation $$\begin{aligned} \left( \frac{q'}{\sqrt{1-(q')^2}}\right) ' +q = G^{\prime }(q) +h(t), \end{aligned}$$ q ′ 1 - ( q ′ ) 2 ′ + q = G ′ ( q ) + h ( t ) , admits at least a periodic solution when $$h\in L^1 (0, T)$$ h ∈ L 1 ( 0 , T ) and G is singular at zero.
Publisher: Springer Science and Business Media LLC
Date: 30-04-2022
DOI: 10.1007/S10231-022-01202-0
Abstract: In this paper, we consider the following coupled gradient-type quasilinear elliptic system $$\begin{aligned} \left\{ \begin{array}{*{20}l} - {\text{ }} ( a(x, u, \nabla u) ) + A_t (x, u, \nabla u) = G_u(x, u, v) & {}{\hbox { in }}\Omega ,\\ - {\text{ }} ( b(x, v, \nabla v) ) + B_t(x, v, \nabla v) = G_v\left( x, u, v\right) & {}{\hbox { in }}\Omega ,\\ u = v = 0 & {}{\hbox { on }}\partial \Omega , \end{array} \right. \end{aligned}$$ - ( a ( x , u , ∇ u ) ) + A t ( x , u , ∇ u ) = G u ( x , u , v ) in Ω , - ( b ( x , v , ∇ v ) ) + B t ( x , v , ∇ v ) = G v x , u , v in Ω , u = v = 0 on ∂ Ω , where $$\Omega$$ Ω is an open bounded domain in $${\mathbb {R}}^N$$ R N , $$N\ge 2$$ N ≥ 2 . We suppose that some $$\mathcal {C}^{1}$$ C 1 –Carathéodory functions $$A, B:\Omega \times {\mathbb {R}}\times {\mathbb {R}}^N\rightarrow {\mathbb {R}}$$ A , B : Ω × R × R N → R exist such that $$a(x,t,\xi ) = \nabla _{\xi } A(x,t,\xi )$$ a ( x , t , ξ ) = ∇ ξ A ( x , t , ξ ) , $$A_t(x,t,\xi ) = \frac{\partial A}{\partial t} (x,t,\xi )$$ A t ( x , t , ξ ) = ∂ A ∂ t ( x , t , ξ ) , $$b(x,t,\xi ) = \nabla _{\xi } B(x,t,\xi )$$ b ( x , t , ξ ) = ∇ ξ B ( x , t , ξ ) , $$B_t(x,t,\xi ) =\frac{\partial B}{\partial t}(x,t,\xi )$$ B t ( x , t , ξ ) = ∂ B ∂ t ( x , t , ξ ) , and that $$G_u(x, u, v)$$ G u ( x , u , v ) , $$G_v(x, u, v)$$ G v ( x , u , v ) are the partial derivatives of a $$\mathcal {C}^{1}$$ C 1 –Carathéodory nonlinearity $$G:\Omega \times {\mathbb {R}}\times {\mathbb {R}}\rightarrow {\mathbb {R}}$$ G : Ω × R × R → R . Roughly speaking, we assume that $$A(x,t,\xi )$$ A ( x , t , ξ ) grows at least as $$(1+|t|^{s_1p_1})|\xi |^{p_1}$$ ( 1 + | t | s 1 p 1 ) | ξ | p 1 , $$p_1 1$$ p 1 1 , $$s_1 \ge 0$$ s 1 ≥ 0 , while $$B(x,t,\xi )$$ B ( x , t , ξ ) grows as $$(1+|t|^{s_2p_2})|\xi |^{p_2}$$ ( 1 + | t | s 2 p 2 ) | ξ | p 2 , $$p_2 1$$ p 2 1 , $$s_2 \ge 0$$ s 2 ≥ 0 , and that G ( x , u , v ) can also have a supercritical growth related to $$s_1$$ s 1 and $$s_2$$ s 2 . Since the coefficients depend on the solution and its gradient themselves, the study of the interaction of two different norms in a suitable Banach space is needed. In spite of these difficulties, a variational approach is used to show that the system admits a nontrivial weak bounded solution and, under hypotheses of symmetry, infinitely many ones.
Publisher: Springer Science and Business Media LLC
Date: 08-10-2022
Location: Italy
No related grants have been discovered for Caterina Sportelli.