Analysis of a dynamic viscoelastic-viscoplastic piezoelectric contact problem

In this paper, we study, from both variational and numerical points of view, a dynamic contact problem between a viscoelastic-viscoplastic piezoelectric body and a deformable obstacle. The contact is modelled using the classical normal compliance contact condition. The variational formulation is written as a nonlinear ordinary differential equation for the stress field, a nonlinear hyperbolic variational equation for the displacement field and a linear variational equation for the electric potential field. An existence and uniqueness result is proved using Gronwall’s lemma, adequate auxiliary problems and fixed-point arguments. Then, fully discrete approximations are introduced using an Euler scheme and the finite element method, for which some a priori error estimates are derived, leading to the linear convergence of the algorithm under suitable additional regularity conditions. Finally, some two-dimensional numerical simulations are presented to show the accuracy of the algorithm and the behaviour of the solution

Effect of a Mediterranean Diet Intervention on Dietary Glycemic Load and Dietary Glycemic Index: The PREDIMED Study

© 2014 Ana Isabel Rodríguez-Rejón et al. Objective. To compare the one year effect of two dietary interventions with MeDiet on GL and GI in the PREDIMED trial. Methods. Participants were older subjects at high risk for cardiovascular disease. This analysis included 2866 nondiabetic subjects. Diet was assessed with a validated 137-item food frequency questionnaire (FFQ). The GI of each FFQ item was assigned by a 5-step methodology using the International Tables of GI and GL Values. Generalized linear models were fitted to assess the relationship between the intervention group and dietary GL and GI at one year of follow-up, using control group as reference. Results. Multivariate-adjusted models showed an inverse association between GL and MeDiet + extra virgin olive oil (EVOO) group: β = -8.52 (95% CI: -10.83 to -6.20) and MeDiet + Nuts group: β = -10.34 (95% CI: -12.69 to -8.00), when comparing with control group. Regarding GI, β = -0.93 (95% CI: -1.38 to -0.49) for MeDiet + EVOO, β = -1.06 (95% CI: -1.51 to -0.62) for MeDiet + Nuts when comparing with control group. Conclusion. Dietary intervention with MeDiet supplemented with EVOO or nuts lowers dietary GL and GI.The authors thank the participants of the trial for their enthusiastic collaboration, the PREDIMED personnel for excellent assistance, and the personnel of all primary care centers affiliated. This work has been supported by the official funding agency for biomedical research of the Spanish government, Instituto de Salud Carlos III (ISCIII), through Grants provided to research networks specifically developed for the trial (RTIC G03/140; RTIC RD 06/0045, Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBERobn)) and by Grants from Centro Nacional de Investigaciones Cardiovasculares (CNIC 06/2007), Fondo de Investigación Sanitaria-Fondo Europeo de Desarrollo Regional (PI04-2239, PI 05/2584, CP06/00100, PI07/0240, PI07/1138, PI07/0954, PI 07/0473, PI10/01407, PI10/02658, PI11/01647, and P11/02505), Ministerio de Ciencia e Innovación (AGL-2009-13906-C02 and AGL2010-22319-C03), Fundación Mapfre 2010, Agencia Canaria de Investigación, Innovación y Sociedad de la Información-EU FEDER (PI 2007/050), Consejería de Salud de la Junta de Andalucía (PI0105/2007), Public Health Division of the Department of Health of the Autonomous government of Catalonia, Generalitat Valenciana (ACOMP06109, GVACOMP2010-181, GVACOMP2011-151, CS2010-AP-111, and CS2011-AP-042), Gobierno Regional de Navarra (P27/2011) and Rio Hortega postresidency fellowship of the Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Spanish government. Itandehui Castro-Quezada is supported by a scholarship of the National Council on Science and Technology of México (CONACYT).Peer Reviewe

Analysis of a dynamic viscoelastic-viscoplastic piezoelectric contact problem

In this paper, we study, from both variational and numerical points of view, a dynamic contact problem between a viscoelastic-viscoplastic piezoelectric body and a deformable obstacle. The contact is modelled using the classical normal compliance contact condition. The variational formulation is written as a nonlinear ordinary differential equation for the stress field, a nonlinear hyperbolic variational equation for the displacement field and a linear variational equation for the electric potential field. An existence and uniqueness result is proved using Gronwall’s lemma, adequate auxiliary problems and fixed-point arguments. Then, fully discrete approximations are introduced using an Euler scheme and the finite element method, for which some a priori error estimates are derived, leading to the linear convergence of the algorithm under suitable additional regularity conditions. Finally, some two-dimensional numerical simulations are presented to show the accuracy of the algorithm and the behaviour of the solution

Potato consumption does not increase blood pressure or incident hypertension in 2 cohorts of Spanish adults

5 TablasBackground: Potatoes have a high glycemic load but also antioxidants, vitamins, and minerals. It is unclear what mechanisms are involved in relation to their effect on blood pressure (BP) and hypertension. Objectives: This study aimed to assess the association between potato consumption, BP changes, and the risk of hypertension in 2 Spanish populations. Methods: Separate analyses were performed in PREDIMED (PREvención con DIeta MEDiterránea), a multicenter nutrition intervention trial of adults aged 55-80 y, and the SUN (Seguimiento Universidad de Navarra) project, a prospective cohort made up of university graduates and educated adults with ages (means±SDs) of 42.7±13.3 y for men and 35.1± 10.7 y for women. In PREDIMED, generalized estimating equations adjusted for lifestyle and dietary characteristics were used to assess changes in BP across quintiles of total potato consumption during a 4-y follow-up. Controlled BP values (systolic BP < 140 mm Hg and diastolic BP < 90 mm Hg) during follow-up were also assessed. For SUN, multivariateadjusted HRs for incident hypertension during a mean 6.7-y follow-up were calculated. Results: In PREDIMED, the total potato intake was 81.9 ± 40.6 g/d. No overall differences in systolic or diastolic BP changes were detected based on consumption of potatoes. For total potatoes, the mean difference in change between quintile 5 (highest intake) and quintile 1 (lowest intake) in systolic BP after multivariate adjustment was 20.90 mm Hg (95% CI: -2.56, 0.76 mm Hg; P-trend = 0.1) and for diastolic BP was 20.02 mm Hg (95% CI: -0.93, 0.89 mm Hg; P-trend = 0.8). In SUN, the total potato consumption was 52.7 ± 33.6 g/d, and no significant association between potato consumption and hypertension incidence was observed in the fully adjusted HR for total potato consumption (quintile 5 compared with quintile 1: 0.98; 95% CI: 0.80, 1.19; P-trend = 0.8). Conclusions: Potato consumption is not associated with changes over 4 y in blood pressure among older adults in Spain or with the risk of hypertension among Spanish adults.Supported by the official funding agency for biomedical research of the Spanish Government, Instituto de Salud Carlos III through grants provided to research networks specifically developed for the trial (RTIC G03/140, to RE; RTIC RD 06/0045, to MAM-G) and through Centro de Investigación Biomédica en Red de Fisiopatología de la Obesidad y Nutrición (CIBERobn), and by grants from Centro Nacional de Investigaciones Cardiovasculares (CNIC 06/2007), Fondo de Investigación Sanitaria–Fondo Europeo de Desarrollo Regional [Proyecto de Investigación (PI) 04-2239, PI 05/2584, CP06/00100, PI07/0240, PI07/1138, PI07/0954, PI 07/0473, PI10/01407, PI10/02658, PI11/01647, P11/02505 and PI13/00462], Ministerio de Ciencia e Innovación [Recursos y teconologia agroalimentarias (AGL)-2009-13906-C02 and AGL2010-22319-C03 and AGL2013-49083-C3-1-R], Fundación Mapfre 2010, the Consejería de Salud de la Junta de Andalucía (PI0105/2007), the Public Health Division of the Department of Health of the Autonomous Government of Catalonia, Generalitat Valenciana [Generalitat Valenciana Ayuda Complementaria (GVACOMP) 06109, GVACOMP2010-181, GVACOMP2011-151], Conselleria de Sanitat y AP; Atención Primaria (CS) 2010-AP-111 and CS2011-AP-042, and Regional Government of Navarra (P27/2011)