Hybrid masonry shell technology in the work of Idelfonso Sánchez del Río

Idelfonso Sánchez del Río is a less known pioneer of reinforced concrete shells in Spain who through his career designed and patented ribbed construction systems for large spanning slabs and vaults and in particular shell enclosures using a hybrid system of concrete and masonry infills. The module called “dovela-onda” or wave-voussoir was made of large ceramic blocks forming a short barrel with flanges at the edges. This paper aims to discuss the technical innovations of this system and assess its structural efficiency. The design and construction process will be studied through literature published by Sánchez del Rio and surveys of two case studies in Oviedo (Spain), the Sports Hall (1977) and a warehouse in Granda. In order to assess their structural efficiency, his own calculation process will be verified by thrust line analysis and Finite Element spatial elastic modelling. The FE model allows the failure mode and the distribution of the loads to be assessed, and gives further insight to the behaviour of the scheme and the design and construction process

Eleutherodactylus zygodactylus

Number of Pages: 2Integrative BiologyGeological Science

Reassessing the WIC Effect: Evidence from the Pregnancy Nutrition Surveillance System

Recent analyses differ on how effective the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) is at improving infant health. We use data from nine states that participate in the Pregnancy Nutrition Surveillance System to address limitations in previous work. With information on the mother's timing of WIC enrollment, we test whether greater exposure to WIC is associated with less smoking, improved weight gain during pregnancy, better birth outcomes, and greater likelihood of breastfeeding. Our results suggest that much of the often-reported association between WIC and lower rates of preterm birth is likely spurious, the result of gestational age bias. We find modest effects of WIC on fetal growth, inconsistent associations between WIC and smoking, limited associations with gestational weight gain, and some relationship with breast feeding. A WIC effect exists, but on fewer margins and with less impact than has been claimed by policy analysts and advocates.

Cross-national validation of the resources depletion-recovery model: An empirical study of Spanish and British theme park employees

Surface acting (SA) refers to the strategy whereby front-line employees hide their own emotions and fake those required of them within their role within customer service transactions. Although researchers have associated SA with burnout, evidence now suggests that this could be an indirect relationship. Building on the Conservation of Resources theory, it was hypothesised that the combined effect of emotional effort and lack of rewarding interactions with customers triggered by SA would explain the strong association between SA and burnout (Studies 1 and 2). Furthermore, building on psychological recovery literature, it was hypothesised that the effort invested in SA would be a weaker predictor of front-line employees’ burnout in cases when they reported higher levels of recovery ability as opposed to lower levels (Study 2). A cross-national and cross-sectional design was used, and participants were theme park employees from UK (Study 1, NUK =204) and Spain (Study 2, NSpain=211). The explanatory role of emotional effort and rewarding interactions was supported, and the buffering effect of recovery ability was confirmed. Strategies aimed at minimising burnout risk for employees who deal with customers on a regular basis in these countries are discussed

The locus of points of the Hilbert scheme with bounded regularity

In this paper we consider the Hilbert scheme $Hilb_{p(t)}^n$ parameterizing subschemes of $P^n$ with Hilbert polynomial $p(t)$, and we investigate its locus containing points corresponding to schemes with regularity lower than or equal to a fixed integer $r'$. This locus is an open subscheme of $Hilb_{p(t)}^n$ and, for every $s\geq r'$, we describe it as a locally closed subscheme of the Grasmannian $Gr_{p(s)}^{N(s)}$ given by a set of equations of degree $\leq \mathrm{deg}(p(t))+2$ and linear inequalities in the coordinates of the Pl\"ucker embedding.Comment: v2: new proofs relying on the functorial definition of the Hilbert scheme. v3: Sections reorganized, new self-contained proof of the representability of the Hilbert functor with bounded regularity (Section 6

Contractile stresses in cohesive cell layers on finite-thickness substrates

Using a minimal model of cells or cohesive cell layers as continuum active elastic media, we examine the effect of substrate thickness and stiffness on traction forces exerted by strongly adhering cells. We obtain a simple expression for the length scale controlling the spatial variation of stresses in terms of cell and substrate parameters that describes the crossover between the thin and thick substrate limits. Our model is an important step towards a unified theoretical description of the dependence of traction forces on cell or colony size, acto-myosin contractility, substrate depth and stiffness, and strength of focal adhesions, and makes experimentally testable predictions.Comment: 5 pages, 3 figure