DSpace Collection:
http://hdl.handle.net/10174/1009
2024-08-12T13:57:26ZExpansion properties of double standard maps
http://hdl.handle.net/10174/36484
Title: Expansion properties of double standard maps
Authors: Benedicks, Michael; Misiurewicz, Michal; Ana, Rodrigues
Abstract: For the family of Double Standard Maps fa;b = 2x + a + b
_ sin 2_x
(mod 1) we investigate the structure of the space of parameters a when b = 1
and when b 2 [0; 1). In the _rst case the maps have a critical point, but for a
set of parameters E1 of positive Lebesgue measure there is an invariant absolutely
continuous measure for fa;1. In the second case there is an open nonempty set Eb
of parameters for which the map fa;b is expanding. We show that as b % 1, the set
Eb accumulates on many points of E1 in a regular way from the measure point of
view.2023-01-01T00:00:00ZModeling the facets of burnout in Lisbon airport border officers using PLSc-SEM estimator
http://hdl.handle.net/10174/35902
Title: Modeling the facets of burnout in Lisbon airport border officers using PLSc-SEM estimator
Authors: Grilo, Luis M.; Braz, Tiago F.; Grilo, Helena L.; Maidana, Jean P.; Stehlik, Milan
Abstract: Border officers experience stressful moments during the working day at the border point at Lisbon airport (Portugal) that can lead to “emotional exhaustion,” which is the core component of burnout, and relates with “cognitive fatigue (weariness)” and “physical fatigue.”
These theoretical concepts cannot be measured (or observed) directly
by what are considered latent variables/constructs that are available in Shirom-Melamed Burnout Measure (SMBM). These constructs are, however, operationalized by the questions available in the SMBM, which correspond to observed variables (or manifest variables) expressed in an ordinal scale of seven categories. This questionnaire, reliable and internationally validated, was used in our research and considering the specialized literature, we proposed a hypothetical structural path model that expresses a priori perceptions about the causal relationships between the mentioned latent constructs, where “physical fatigue” is the target construct. A reflective model was estimated based on the sample of primary data and using a Variance-Covariance estimator of Structural Equations Modeling (VB-SEM), the consistent Partial Least Squares (PLSc), that corrects for bias to consistently estimate SEM’s with common factors. The results obtained allow a better understanding of the profile and characteristics of Portuguese border officers who work at Lisbon airport, as well as reveal that the latent exogenous construct “emotional exhaustion” has a high positive direct effect on the “cognitive fatigue,” and through this latter (mediator construct), an indirect effect on the endogenous construct “physical fatigue.” In turn, “cognitive fatigue” has the greatest positive direct effect on “physical fatigue.” The biggest difference identified was between the direct effect of “Emotional exhaustion” on “Physical fatigue,” which is higher for workers with more years of service, as expected. However, the multigroup analysis (using the nonparametric Permutation test) showed that this difference was not statistically significant.2023-10-12T23:00:00ZArtinian Gorenstein algebras of embedding dimension four and socle degree three
http://hdl.handle.net/10174/35620
Title: Artinian Gorenstein algebras of embedding dimension four and socle degree three
Authors: Macias Marques, Pedro; Veliche, Oana; Weyman, Jerzy
Abstract: We prove that in the polynomial ring ${Q=\kk[x,y,z,w]}$, with $\kk$ an algebraically closed field of characteristic zero, all Gorenstein homogeneous ideals $I$ such that $(x,y,z,w)^4\subseteq I \subseteq (x,y,z,w)^2$ can be obtained by \emph{doubling} from a grade three perfect ideal $J\subset I$ such that $Q/J$ is a locally Gorenstein ring. Moreover, a graded minimal free resolution of the \mbox{$Q$-module} $Q/I$ can be completely described in terms of a graded minimal free resolution of the \mbox{$Q$-module} $Q/J$ and a homogeneous embedding of a shift of the canonical module $\omega_{Q/J}$ into $Q/J$.2023-01-01T00:00:00ZCohomological Blowups of Graded Artinian Gorenstein Algebras along Surjective Maps
http://hdl.handle.net/10174/35546
Title: Cohomological Blowups of Graded Artinian Gorenstein Algebras along Surjective Maps
Authors: Iarrobino, Anthony; Macias Marques, Pedro; McDaniel, Chris; Seceleanu, Alexandra; Watanabe, Junzo
Abstract: We introduce the cohomological blowup of a graded Artinian Gorenstein algebra along a surjective map, which we term BUG (blowup Gorenstein) for short. This is intended to translate to an algebraic context the cohomology ring of a blowup of a projective manifold along a projective submanifold. We show, among other things, that a BUG is a connected sum, that it is the general fiber in a flat family of algebras, and that it preserves the strong Lefschetz property. We also show that standard graded compressed algebras are rarely BUGs, and we classify those BUGs that are complete intersections. We have included many examples throughout this manuscript.2023-01-01T00:00:00Z