Mimetic Discretizations of Elliptic Control Problems

We investigate the performance of the Mimetic Finite Difference (MFD) method for the approximation of a constraint optimal control problem governed by an elliptic operator. Low-order and high-order mimetic discretizations are considered and a priori error estimates are derived, in a suitable discrete norm, for both the control and the state variables. A wide class of numerical experiments performed on a set of examples selected from the literature assesses the robustness of the MFD method and confirms the convergence analysis.     

Nisin as a Food Preservative: Part 1: Physicochemical Properties,Antimicrobial Activity,and Main Uses

Nisin is a natural preservative for many food products. This bacteriocin is mainly used in dairy and meat products. Nisin inhibits pathogenic food borne bacteria such as Listeria monocytogenes and many other Gram-positive food spoilage microorganisms. Nisin can be used alone or in combination with other preservatives or also with several physical treatments. This paper reviews physicochemical and biological properties of nisin, the main factors affecting its antimicrobial effectiveness, and its food applications as an additive directly incorporated into food matrices.     

Adapting technology: effect of high-involvement HRM and organisational trust

This study is designed to empirically test a model of high-involvement human resource management (HIHRM), organisational trust, and technology adaptation grounded on social exchange theory in the context of the private banking sector. The proposed model intends to add to the understanding of the effect of HIHRM on technology adaptation via the mediating influence of organisational trust. Frontline employees were surveyed using a self-administered questionnaire. Results from partial least square-structural equation modelling suggest that there is a significant influence of HIHRM on technology adaptation. Organisational trust further mediates the relationship. Thus, this paper finds an answer to the ‘black box’ of human resource management (HRM) practices, explaining how HIHRM influences employees’ attitudes towards technology adaptation. The study can help management have a better understanding of the importance of employee involvement-oriented HRM in introducing and implementing a new technology through the integration of trust processes in the organisation.     

Does carbon nanopowder threaten amphibian development?

Lethal and teratogenic potentials of carbon nanoparticles (CNPs) in their amorphous form were investigated by the standardized Frog Embryo Teratogenesis Assay-Xenopus (FETAX), a 96-h in vitro whole-embryo toxicity test based on the amphibian Xenopus laevis. Embryos were acutely exposed to 1, 10, 100 and 500 mg/L CNP suspensions and evaluated for lethality, malformations and growth inhibition. Larvae were processed for histological and ultrastructural analyses to detect the main affected organs, to look for specific lesions at the subcellular level and to image and track CNPs into tissues. Only the highest CNP suspension resulted in being embryolethal for X. laevis larvae, while malformed larva percentages significantly differed from controls starting from 100 mg/L. The stomach and gut were the preferential CNP accumulation sites, on the contrary, the digestive epithelium remained intact. The analyses showed the presence of isolated nanoparticles and/or aggregates in different secondary target organs. CNPs were found in circulating erythrocytes. The research confirms the good tolerance of X. laevis towards pure elemental carbon in its nanoparticulate amorphous form, but highlights the possibility of CNP transfer toward all body areas.     

Effect of extra virgin olive oil on glycaemia in healthy young subjects

In this approach we studied the glycaemia levels in 20 healthy young volunteers (26 ± 2 years), before and after a 30‐day intake of 50 mL of extra virgin olive oil (EVOO). We selected an oil rich in phenolic compounds (523 mg/L) with a high content of secoiridoidic derivatives (over 94.5%). The findings from our study reveal a significant decrease of glycaemia from 89.6 ± 6.8 to 82.7 ± 10.3 mg/dL (p<0.05), related to a long term daily intake of the study EVOO, as the only added fat. A significant increment of the HDL cholesterol, from 68.7 ± 11.5 to 75.2 ± 4.9 mg/dL, was also highlighted. Total cholesterol, LDL, VLDL, triglycerides, and blood pressure did not show significant variation after the 30‐day consumption of this EVOO. So far, few articles have described the influence of EVOO consumption, on plasma glucose levels in humans. This effect is observed in a group of healthy young humans. Moreover, we confirm that the level of free hydroxytyrosol (OH‐Tyr) in plasma increased up to fourfold (p<0.05) after the 30‐day intake of this EVOO. In addition, the excretion in urine of the main metabolite of OH‐Tyr, homovanillic acid (HVA), significantly increased.     

Optimal utilisation level for lean product development in a multitasking context

Flow of information is of utmost importance during product development (PD) endeavours with timely feedback supporting the resolution of higher risk elements. PD task size, multitasking and resource utilisation levels of the PD system influence information flow and the value ultimately realised from the investment in PD. In this paper, a model incorporating a methodology developed using queuing theory, and in particular, results obtained for Jackson networks are extended to help engineering management to improve PD task flow and consequently become more ‘lean’. Considered factors include: optimal PD task size and multitasking (focus) level as well as the utilisation level of PD resources. Empirical data were collected from a case study company and compared to optimal values. The benefits of the proposed model and approaches are discussed.