Four Decades of Studying Global Linear Instability: Progress and Challenges

Global linear instability theory is concerned with the temporal or spatial development of small-amplitude perturbations superposed upon laminar steady or time-periodic three-dimensional flows, which are inhomogeneous in two(and periodic in one)or all three spatial directions.After a brief exposition of the theory,some recent advances are reported. First, results are presented on the implementation of a Jacobian-free Newton–Krylov time-stepping method into a standard finite-volume aerodynamic code to obtain global linear instability results in flows of industrial interest. Second, connections are sought between established and more-modern approaches for structure identification in flows, such as proper orthogonal decomposition and Koopman modes analysis (dynamic mode decomposition), and the possibility to connect solutions of the eigenvalue problem obtained by matrix formation or time-stepping with those delivered by dynamic mode decomposition, residual algorithm, and proper orthogonal decomposition analysis is highlighted in the laminar regime; turbulent and three-dimensional flows are identified as open areas for future research. Finally, a new stable very-high-order finite-difference method is implemented for the spatial discretization of the operators describing the spatial biglobal eigenvalue problem, parabolized stability equation three-dimensional analysis, and the triglobal eigenvalue problem; it is shown that, combined with sparse matrix treatment, all these problems may now be solved on standard desktop computer

The stereotomy of keystones in european early gothic: different geometric designs and construction solutions

[EN] The sexpartite vault was the great protagonist of the beginnings of Gothic architecture in Europe and outstanding vaulting was built using this system in Europe’s important cathedrals and monasteries, such as Notre Dame de Paris or Canterbury. By making a comparative study of the principal examples we have been able to bring to light he knowledge of geometry and construction present in Early Gothic architecture and show how it evolved to the remarkable level of stereotomic development achieved in the High Gothic. The carving of the keystone was one of the most complicated challenges of the vault as it received the different tilted ribs at varying angles on plan and in elevation, which entailed considerable knowledge of geometry. The evolution of Gothic stereotomy is reflected in this element and we found three different solutions that show development using diverse techniques to facilitate geometric design and the carving process.[ES] La bóveda sexpartita es la gran protagonista del gótico primitivo europeo y con ella se llevaron a cabo importantes abovedamientos en las catedrales y monasterios de mayor relevancia, como Notre Dame de París o Canterbury. El estudio comparativo de sus principales ejemplos nos ha permitido poner de manifiesto los conocimientos geométricos y constructivos en el gótico primitivo y su evolución hasta alcanzar el enorme desarrollo estereotómico del gótico clásico.La clave es una de las piezas más complicadas en su talla ya que recibe los distintos nervios de la bóveda con inclinaciones y ángulos diferentes en planta y alzado, lo que requiere importantes conocimientos geométricos. La evolución de la estereotomía gótica quedó reflejada en este elemento donde encontramos tres soluciones que muestran diferentes grados de desarrollo con distintas técnicas para facilitar su diseño geométrico y el trabajo de la labra.Maira Vidal, R. (2017). La estereotomía de las claves en el gótico primitivo europeo: diferentes diseños geométricos y soluciones constructivas. EGA. Revista de Expresión Gráfica Arquitectónica. 22(30):152-159. doi:10.4995/ega.2017.7847.SWORD1521592230Choisy, A., 1996. Histoire de l'architecture. France: Bibliothèque de l'Image.Gómez Martínez, J., 1998. El gótico espa-ol de la Edad Moderna: bóvedas de crucería. Valladolid: Universidad de Valladolid.Maira Vidal, R., 2016. Bóvedas sexpartitas. Los orígenes del gótico. Tesis (Doctoral) E.T.S. Arquitectura (UPM).Palacios Gonzalo, J.C., 2009. La cantería medieval. La construcción de la bóveda gótica espa-ola. Madrid: Munilla-Lería.Viollet Le Duc, E., 1996. La construcción medieval. Madrid: Instituto Juan de Herrera.Willis, R., 1910. On the Construction of the vaults of the Middle Ages. London: The Royal Institute of British Architects

Associations between macronutrient intake and serum lipid profile depend on body fat in European adolescents: the Healthy Lifestyle in Europe by Nutrition in Adolescence (HELENA) study

The present study aimed to investigate the relationships between macronutrient intake and serum lipid profile in adolescents from eight European cities participating in the HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) cross-sectional study (2006–7), and to assess the role of body fat-related variables in these associations. Weight, height, waist circumference, skinfold thicknesses, total choles- terol, HDL-cholesterol (HDL-C), LDL-cholesterol, TAG, apoB and apoA1 were measured in 454 adolescents (44 % boys) aged 12·5–17·5 years. Macronutrient intake (g/4180 kJ per d (1000 kcal per d)) was assessed using two non-consecutive 24 h dietary recalls. Associations were evaluated by multi-level analysis and adjusted for sex, age, maternal education, centre, sum of four skinfolds, moderate-to-vigorous

Tissue-Specific Orchestration of Gilthead Sea Bream Resilience to Hypoxia and High Stocking Density

Two different O-2 levels (normoxia: 75-85% O-2 saturation; moderate hypoxia: 42-43% O-2 saturation) and stocking densities (LD: 9.5, and HD: 19 kg/m(3)) were assessed on gilthead sea bream (Sparus aurata) in a 3-week feeding trial. Reduced O-2 availability had a negative impact on feed intake and growth rates, which was exacerbated by HD despite of the improvement in feed efficiency. Blood physiological hallmarks disclosed the enhancement in O-2-carrying capacity in fish maintained under moderate hypoxia. This feature was related to a hypo-metabolic state to cope with a chronic and widespread environmental O-2 reduction, which was accompanied by a differential regulation of circulating cortisol and growth hormone levels. Customized PCR-arrays were used for the simultaneous gene expression profiling of 34-44 selected stress and metabolic markers in liver, white skeletal muscle, heart, and blood cells. The number of differentially expressed genes ranged between 22 and 19 in liver, heart, and white skeletal muscle to 5 in total blood cells. Partial Least-Squares Discriminant Analysis (PLS-DA) explained [R2Y(cum)] and predicted [Q2Y(cum)] up to 95 and 65% of total variance, respectively. The first component (R2Y = 0.2889) gathered fish on the basis of O-2 availability, and liver and cardiac genes on the category of energy sensing and oxidative metabolism (cs, hif-1 alpha, pgc1 alpha, pgc1 beta, sirts 1-2-4-5-6-7), antioxidant defense and tissue repair (prdx5, sod2, mortalin, gpx4, gr, grp-170, and prdx3) and oxidative phosphorylation (nd2, nd5, and coxi) highly contributed to this separation. The second component (R2Y = 0.2927) differentiated normoxic fish at different stocking densities, and the white muscle clearly promoted this separation by a high over-representation of genes related to GH/IGF system (ghr-i, igfbp6b, igfbp5b, insr, igfbp3, and igf-i). The third component (R2Y = 0.2542) discriminated the effect of stocking density in fish exposed to moderate hypoxia by means of hepatic fatty acid desaturases (fads2, scd1a, and scd1b) and muscle markers of fatty acid oxidation (cpt1a). All these findings disclose the different contribution of analyzed tissues (liver >= heart > muscle > blood) and specific genes to the hypoxic- and crowding stress-mediated responses. This study will contribute to better explain and understand the different stress resilience of farmed fish across individuals and species

Apoyo social y dependencia percibida en cuidadores familiares de pacientes con enfermedades crónicas

Objective: To describe social support and perceived dependency in family caregivers of people with chronic diseases.Methods: Descriptive, cross-sectional study; conducted on 56 informal caregivers of people with chronic diseases, purposively selected. An online form was used for data collection.Results: The mean age of informal caregivers was 46.6 years, with a greater predominance of women (89.3%), almost 70% were unemployed and 43% had upper secondary education. Regarding social support, 55.4% of the participants perceived it as normal on the total scale and in its affective dimension (53.6%), but they perceived little confidential support (53.6%). Regarding the perceived dependency of their patient, they perceived him to be moderately dependent (39.3%), followed by severely dependent (21.4%), requiring more support in personal hygiene, getting up and down stairs, dressing and undressing, and moving around.Conclusions: The socio-demographic profile of informal caregivers corresponds to a female, around fifty years of age, who does not work to care for her sick family member. In terms of social support, caregivers perceived little confidential support. The degree of perceived dependency was mostly moderate, followed by severe and total dependency. Addressing family caregivers' perceptions of social support and dependency of the chronically ill is critical for health care professionals to improve the quality of life of family caregivers and to ensure that the care provided is effective and sustainable in the long term.Objetivo: Describir el apoyo social y la dependencia percibida en cuidadores familiares de personas con enfermedades crónicas.Método: Estudio descriptivo, transversal; realizado en 56 cuidadores informales de personas con enfermedades crónicas, seleccionados intencionalmente. Se utilizó un formulario online para la recogida de datos.Resultados: La edad media de los cuidadores informales fue de 46,6 años, con un mayor predominio de mujeres (89,3%), casi el 70% estaban desempleados y el 43% tenían estudios secundarios superiores. Respecto al apoyo social, el 55,4% de los participantes lo percibían como normal en la escala total y en su dimensión afectiva (53,6%), pero percibían poco apoyo confidencial (53,6%). En cuanto a la dependencia percibida de su paciente, lo percibieron como moderadamente dependiente (39,3%), seguido de severamente dependiente (21,4%); requiriendo más apoyo en la higiene personal, subir y bajar escaleras, vestirse y desvestirse, y desplazarse.Conclusiones: El perfil sociodemográfico de los cuidadores informales corresponde a una mujer, en torno a los cincuenta años, que no trabaja para cuidar a su familiar enfermo. En cuanto al apoyo social, los cuidadores percibieron poco apoyo confidencial. El grado de dependencia percibido fue mayoritariamente moderado, seguido de dependencia severa y total. Abordar las percepciones de los cuidadores familiares sobre el apoyo social y la dependencia de los enfermos crónicos es fundamental para que los profesionales sanitarios mejoren la calidad de vida de los cuidadores familiares y garanticen que la atención prestada sea eficaz y sostenible a largo plaz

Food portion sizes and their relationship with energy, and nutrient intakes in adolescents: The HELENA study

Objectives This study aimed to investigate the associations between portion sizes (PSs) from different food groups and energy, as well as nutrient intakes in European adolescents. Methods A sample of 1631 adolescents (54.2 % girls) were included from the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional (HELENA) study. Mean food PS was calculated by dividing the total intake of the items by the number of eating occasions of these consumed items. To determine the key items for analysis, foods were ranked by frequency of consumption. A one-way between-groups analysis of covariance was used to test for significant differences in means across tertiles. A multivariable linear regression analysis was carried out, adjusting for age, sex, maternal education, body mass index, and using country as a level. Results Energy intake increased with elevated intakes of energy-dense foods. Large portions of rice and other grains, starch roots and potatoes, and meat substitutes, nuts, and pulses were associated with increased carbohydrate and fiber intake. Larger portions of cheese and butter and animal fat were significantly associated with a higher fat intake. Lower intakes of some vitamins and micronutrients were noticed with consumption of larger portions of high energy-dense foods, such as desserts and pudding, margarine and vegetable oil, and butter and animal fat. Conclusions Large food PSs may be associated with positive energy, as well as macro- and micronutrient intake. Moreover, the findings from this study may help the future development of dietary guidance in general and specific to PSs, and support targeted strategies to address intakes of certain nutrients in European adolescents

Oval Domes: History, Geometry and Mechanics

An oval dome may be defined as a dome whose plan or profile (or both) has an oval form. The word Aoval@ comes from the latin Aovum@, egg. Then, an oval dome has an egg-shaped geometry. The first buildings with oval plans were built without a predetermined form, just trying to close an space in the most economical form. Eventually, the geometry was defined by using arcs of circle with common tangents in the points of change of curvature. Later the oval acquired a more regular form with two axis of symmetry. Therefore, an “oval” may be defined as an egg-shaped form, doubly symmetric, constructed with arcs of circle; an oval needs a minimum of four centres, but it is possible also to build polycentric ovals. The above definition corresponds with the origin and the use of oval forms in building and may be applied without problem until, say, the XVIIIth century. Since then, the teaching of conics in the elementary courses of geometry made the cultivated people to define the oval as an approximation to the ellipse, an “imperfect ellipse”: an oval was, then, a curve formed with arcs of circles which tries to approximate to the ellipse of the same axes. As we shall see, the ellipse has very rarely been used in building. Finally, in modern geometrical textbooks an oval is defined as a smooth closed convex curve, a more general definition which embraces the two previous, but which is of no particular use in the study of the employment of oval forms in building. The present paper contains the following parts: 1) an outline the origin and application of the oval in historical architecture; 2) a discussion of the spatial geometry of oval domes, i. e., the different methods employed to trace them; 3) a brief exposition of the mechanics of oval arches and domes; and 4) a final discussion of the role of Geometry in oval arch and dome design

Late orogenic doming in the Eastern Betics : final exhumation of the Nevado-Filabride complex and its relation to basin genesis.

The geometry, timing, and kinematics of late orogenic extension in the Betic Cordilleras pose the problem of a decoupling of upper crustal and lower crustal deformation regimes. Perpendicular directions of extension in metamorphic domes and nearby sedimentary basins remain unexplained. This paper puts kinematic constraints on the final exhumation of the Nevado-Filabride complex, focusing on the formation of metamorphic domes and their relations with the adjacent basins. Structural fabrics and kinematic indicators below the main shear zones as well as their relations with both published changing metamorphic P-T conditions and geochronological data were studied. Our approach describes (1) a consistent top-to-the-west shear parallel to dome axes of during D2 (i.e., during decompression) with distributed ductile flow and the onset of strain localization along major shear zones, (2) further strain localization along the major shear zones under greenschist facies conditions, during D3 leading to S-C′ mylonites formation accompanied with a rock strong thickness reduction, (3) the divergence of shear direction on either limbs of domes during D3 showing the appearance of the dome geometry, and (4) a local evolution toward N-S brittle extension (D4) in the upper plate and formation of sedimentary basins. Continuous ductile to brittle top-to-the-west shear is compatible with the slab retreat hypothesis from the Miocene; the formation of domes which adds gravitational forces responsible for the final stages of exhumation is thus characterized by important kinematics changes necessary to explain coeval N-S opened basins. Later, from the upper Tortonian, a contractional event (D5) amplified the earlier domal structures forming the present north vergent folds