Versal unfoldings for linear retarded functional differential equations

We consider parametrized families of linear retarded functional differential equations (RFDEs) projected onto finite-dimensional invariant manifolds, and address the question of versality of the resulting parametrized family of linear ordinary differential equations. A sufficient criterion for versality is given in terms of readily computable quantities. In the case where the unfolding is not versal, we show how to construct a perturbation of the original linear RFDE (in terms of delay differential operators) whose finite-dimensional projection generates a versal unfolding. We illustrate the theory with several examples, and comment on the applicability of these results to bifurcation analyses of nonlinear RFDEs

Agronomic, physiological and quality response of romaine and red oak-leaf lettuce to nitrogen input

Protecting the environment by improving the crop-system nitrogen (N) use efficiency (NUE) while maximising yield and quality is a primary challenge for modern agriculture, and understanding the processes that govern N fluxes in the plant-soil system is essential to improve NUE. An on-farm study was conducted over two fall-winter seasons to evaluate the NUE, agronomical and physiological response of romaine (var. longifolia, cv Manavert) and red oak-leaf (var. crispa, cv Aruba) lettuce (Lactuca sativa L.) to different N-rates (0, 60, 120, 180 kg ha–1 of N). Nitrogen rate influenced all tested parameters, including plant fresh and dry weight, N accumulation, leaf NO3– and dry matter content, NUE indices, N nutrition index (NNI), soil residual N and the estimated N losses at the end of the crop season. Fresh yield, dry weight and N-accumulation response to N rate were influenced by lettuce genotype. Manavert had higher N recovery, NUE, and lower leaf NO3– concentration than Aruba. Analysing the NNI overtime, 120 kg ha–1 of N assured an optimal N status in both Manavert and Aruba, while N deficiency and excess were observed at lower and higher N-rates, respectively. An empirical relationship was observed between NNI and leaf NO3– concentration, suggesting that leaf NO3– concentration may be used to predict NNI and thus the crop N status. The relationship between NNI and leaf NO3– concentration may be used to define optimal leaf NO3– concentration ranges for the rapid and site-specific assessment of the crop N status, and the dynamic adjustment of N-fertilisation, contributing to improve crop NUE, minimise N-losses, and optimise yield and quality of lettuce crops

Digital interaction: where are we going?

In the framework of the AVI 2018 Conference, the interuniversity center ECONA has organized a thematic workshop on "Digital Interaction: where are we going?". Six contributions from the ECONA members investigate different perspectives around this thematic

Celiac disease in type 1 diabetes mellitus

Celiac Disease (CD) occurs in patients with Type 1 Diabetes (T1D) ranging the prevalence of 4.4-11.1% versus 0.5% of the general population. The mechanism of association of these two diseases involves a shared genetic background: HLA genotype DR3-DQ2 and DR4-DQ8 are strongly associated with T1D, DR3-DQ2 with CD. The classical severe presentation of CD rarely occurs in T1D patients, but more often patients have few/mild symptoms of CD or are completely asymptomatic (silent CD). In fact diagnosis of CD is regularly performed by means of the screening in T1D patients. The effects of gluten-free diet (GFD) on the growth and T1D metabolic control in CD/T1D patient are controversial. Regarding of the GFD composition, there is a debate on the higher glycaemic index of gluten-free foods respect to gluten-containing foods; furthermore GFD could be poorer of fibers and richer of fat. The adherence to GFD by children with CD-T1D has been reported generally below 50%, lower respect to the 73% of CD patients, a lower compliance being more frequent among asymptomatic patients. The more severe problems of GFD adherence usually occur during adolescence when in GFD non compliant subjects the lowest quality of life is reported. A psychological and educational support should be provided for these patients

. Double-microcatheter technique through tortuous anatomy for coil embolization of a saccular splenic aneurysm: a technical report

We report on a case of an asymptomatic splenic artery aneurysm (SAA) with a large neck in a 53-year-old female with an extreme vessel tortuosity which was treated with a Double Microcatheter Technique. This endovascular procedure consists of embolization of the aneurysm using detachable coils with no application of any glue, stent or balloon. At the end of procedure, no complications occurred. At the three-month follow-up an MRI showed the aneurysm’s complete exclusion and patency of the splenic artery