Crone control of a nonlinear hydraulic actuator

The CRONE control (fractional robust control) of a hydraulic actuator whose dynamic model is nonlinear is presented. An input-output linearization under diffeomorphism and feedback is first achieved for the nominal plant. The relevance of this linearization when the parameters of the plant vary is then analyzed using the Volterra input-output representation in the frequency domain. CRONE control based on complex fractional differentiation is finally applied to control the velocity of the input-output linearized model when parametric variations occur

Input-output linearization and fractional robust control of a non-linear system

This article deals with the association of a linear robust controller and an input-output linearization feedback for the control of a perturbed and non-linear system. This technique is applied to the control of a hydraulic system whose actuator is non-linear and whose load is time-variant. The piston velocity of the actuator needs to be controlled and a pressure-difference inner-loop is used to improve the performance. To remove the effect of the non-linearity, an input-output linearization under diffeomorphism and feedback is achieved. CRONE control, based on complex fractional differentiation, is applied to design a controller for piston-velocity loop even when parametric variations occu

Dynamique des systèmes agraires irrigués anciens : représentations synchroniques et diachroniques : l'exemple d'Urcuqui en Equateur

Les réseaux d'irrigation anciens représentent dans le monde près de la moitié des superficies irriguées et la majorité des paysans utilisant l'irrigation produisent sous ces canaux au passé parfois millénaire. Délaissés par le développement moderne, méconnus des chercheurs, ces réseaux connaissent pour une grande part des difficultés de fonctionnement. La réhabilitation de ces systèmes semble constituer un thème majeur pour le développement agricole des prochaines décennies. Des chercheurs engagés dans une réflexion sur les réhabilitations de réseaux de montagne en Equateur témoignent de la complexité des dysfonctionnements, proposent des outils pour comprendre les évolutions en combinant une approche diachronique des réseaux et une représentation synchronique des systèmes agraires. Une modélisation d'un système agraire irrigué local a été réalisée ex-ante dans le but de promouvoir une négociation sur le changement technique et social entre les partenaires des réhabilitations, administrations de l'eau et associations de paysans. (Résumé d'auteur

Reducing the burden of iron deficiency anemia in Cote D'Ivoire through fortification

Iron deficiency anemia (IDA) is highly prevalent in the Cote d'Ivoire and has severe health and economic consequences. In this paper, we apply a health economic model to quantify the burden of IDA, and the contribution of nationwide mandatory iron fortification of wheat flour and voluntary iron fortification of condiments to the reduction of this burden

Expression of HLA-G in human cornea, an immune-privileged tissue.

Human leukocyte antigen (HLA)-G retains the capacity to modulate immune responses, favoring the establishment of tolerance in solid-tissue allotransplants. To better understand the mechanisms that promote corneal allograft survival, we investigated whether HLA-G was an immunoregulatory factor involved in corneal immunology. We therefore sought HLA-G expression in corneal tissues. Corneal transplantation consists in replacing the center of a diseased cornea with normal corneal tissue. Two corneal parts are not used in such surgery: diseased central corneal tissue and peripheral normal cornea. For this study, we used healthy corneas obtained from deceased donors and diseased corneas obtained from patients with pseudophakic bullous keratopathy or keratoconus who had undergone corneal transplantation. Immunohistochemical analysis carried out on the cryopreserved corneas showed a positive immunohistochemical staining with anti-HLA-G, anti-HLA-A, -B, and -C, and anti-HLA class I monoclonal antibodies. Staining was obtained for keratocytes, epithelial cells, and endothelial cells from both healthy and pathologic human corneas, revealing the presence of HLA class I proteins, including HLA-G. HLA-G transcripts were detected in normal cornea by reverse transcriptase-polymerase chain reaction with a classical pattern of alternative splicing. The detection of HLA-G protein in adult corneas leads to the conclusion that this protein may contribute to the maintenance of the privileged immune status of cornea

Fractional robust control of a nonlinear plant : Control of a nonlinear testing bench using the singular perturbation technique and the CRONE approach

The control of a hydraulic testing bench is presented by using both singular perturbations technique and Crone control (fractional robust control). The testing bench is constituted of a hydraulic actuator which deforms, with a required velocity, the uncertain mechanical structures to be tested. Thanks to the singular perturbations techniques, the plant can be linearized despite the uncertainty by using a simplified input-output linearization under diffeomorphism and feedback. The Crone control is used to reject remaining nonlinearities considered as perturbations and to control the actuator velocity while taking into account the parametric variations of the mechanical structures

An integrative proteomics method identifies a regulator of translation during stem cell maintenance and differentiation

To characterize molecular changes during cell type transitions, the authors develop a method to simultaneously measure protein expression and thermal stability changes. They apply this approach to study differences between human pluripotent stem cells, their progenies, parental and allogeneic cells. Detailed characterization of cell type transitions is essential for cell biology in general and particularly for the development of stem cell-based therapies in regenerative medicine. To systematically study such transitions, we introduce a method that simultaneously measures protein expression and thermal stability changes in cells and provide the web-based visualization tool ProteoTracker. We apply our method to study differences between human pluripotent stem cells and several cell types including their parental cell line and differentiated progeny. We detect alterations of protein properties in numerous cellular pathways and components including ribosome biogenesis and demonstrate that modulation of ribosome maturation through SBDS protein can be helpful for manipulating cell stemness in vitro. Using our integrative proteomics approach and the web-based tool, we uncover a molecular basis for the uncoupling of robust transcription from parsimonious translation in stem cells and propose a method for maintaining pluripotency in vitro

Women and healthcare providers' perceptions of a midwife-led unit in a Swiss university hospital: a qualitative study.

BACKGROUND: The development of medical-led care in obstetrics over the past decades has contributed to improving outcomes for both mother and child. Although efficiency has improved in complex situations, unnecessary interventions are still practiced in low-risk pregnancies, contrary to international recommendations. A shift to a less interventionist model of care has encouraged many countries to review their policies on maternal health care and develop models such as the "midwife-led unit" (MLU) where the midwife plays a predominant role with a minimum of routine intervention. Existing research has provided convincing evidence that MLUs lead to better maternal and neonatal outcomes when compared to traditional models. They not only improve the level of satisfaction amongst women, but are also associated with reduced healthcare costs. This study aimed to explore the perceptions of women and healthcare providers regarding the creation of an MLU in a Swiss university hospital. METHODS: A descriptive research study using qualitative methods was conducted among pregnant women and new mothers in a Swiss maternity unit, including also midwives and medical staff. Data collection was carried out through one-to-one interviews, focus groups, and telephone interviews (n = 63). After transcription, thematic analysis was performed. RESULTS: The triangulation of perceptions of women and healthcare providers indicated support for the implementation of an MLU to promote physiological delivery. Most women welcomed the idea of an MLU, in particular how it could help in offering continuity of care. Healthcare providers were optimistic about the implementation of an MLU and recognised the need for some women to have access to a less interventionist approach. From the women's perspective, barriers concerned the lack of awareness of midwives' full scope of practice, while barriers for midwives and obstetricians were related to the challenge to develop a good interprofessional collaboration. CONCLUSION: Alternative models to provide maternity care for low-risk women have been developed and evaluated widely in several countries outside Switzerland. This study showed that women and healthcare providers were favourable towards the development of a new care model, while taking into account the specific expectations and barriers raised by participants