Cosmological density perturbations in modified gravity theories

In the context of f(R) theories of gravity, we study the cosmological evolution of scalar perturbations by using a completely general procedure. We find that the exact fourth-order differential equation for the matter density perturbations in the longitudinal gauge, reduces to a second-order equation for sub-Hubble modes. This simplification is compared with the standard (quasi-static) equation used in the literature. We show that for general f(R) functions the quasi-static approximation is not justified. However for those f(R) adequately describing the present phase of accelerated expansion and satisfying local gravity tests, it does give a correct description for the evolution of perturbations.Comment: 4 pages, 2 figures. Contribution to the proceedings of Spanish Relativity Meeting 2008, Salamanca, Spain, 15-19 September 200

OBSERVATIONS ON THE PHYSICAL GEOGRAPHY AND AGRICULTURE OF THE RIO NOSARA WATERSHED IN THE NICOYA PENINSULA OF COSTA RICA

OBSERVATIONS ON THE PHYSICAL GEOGRAPHY AND AGRICULTURE OF THE RIO NOSARA WATERSHED IN THE NICOYA PENINSULA OF COSTA RIC

von Willebrand Factor, Free Hemoglobin and Thrombosis in ECMO

Though extracorporeal membrane oxygenation (ECMO) provides life-saving support, this intervention exposes patients to certain risks. Circulating free hemoglobin (fHb) resulting from mechanically induced hemolysis and insufficient haptoglobin/hemopexin may promote thrombosis within the ECMO circuit. Thrombi in the circuit can result in thromboembolic complications in these patients. Prevention of thrombus formation and propagation in the ECMO circuit may improve clinical outcome. fHb released during hemolysis has been shown to have multiple adverse effects, including thrombosis, but the mechanism by which fHb contributes to thrombosis in an ECMO circuit remains elusive. It is well established that (1) high shear stress generated in the circuit may cause hemolysis, and (2) plasma fibrinogen is adsorbed onto the inner tubing of the ECMO circuit over time. Plasma von Willebrand factor (pVWF) mediates platelet deposition at sites of vascular injury under high shear stress by sensing alterations in the hemodynamic environment. This biophysical property of pVWF that enables hemostasis may also contribute to the pathogenesis of ECMO-induced thrombosis. pVWF contains binding sites for both adsorbed fibrin(ogen) and fHb. High concentrations of fHb increase pVWF-mediated platelet adhesion and thrombus formation on a surface-adsorbed fibrin(ogen) under high shear stress. The molecular mechanism(s) by which fHb drives the conformation of pVWF into a prothrombotic state is currently unknown. Reduction of thrombotic risks during ECMO intervention warrants further investigations into the interaction between pVWF and fHb

Editorial: Cognitive inspired aspects of robot learning

[No abstract available

A State and Territorial Survey Regarding Utilization of Environmental Health Shelter Assessments during Disasters, and a Secondary Analysis of Available Shelter Assessment Data

Disasters are complex events characterized by damage to key infrastructure and population displacements into disaster shelters. Assessing the living environment in shelters during disasters is a crucial health security concern. Until now, jurisdictional knowledge and preparedness on those assessment methods, or deficiencies found in shelters is limited. A cross-sectional survey (STUSA survey) ascertained knowledge and preparedness for those assessments in all 50 states, DC, and 5 US territories. Descriptive analysis of overall knowledge and preparedness was performed. Fisher’s exact statistics analyzed differences between two groups: jurisdiction type and population size. Two logistic regression models analyzed earthquakes and hurricane risks as predictors of knowledge and preparedness. A convenience sample of state shelter assessments records (n=116) was analyzed to describe environmental health deficiencies found during selected events. Overall, 55 (98%) of jurisdictions responded (states and territories) and appeared to be knowledgeable of these assessments (states 92%, territories 100%, p = 1.000), and engaged in disaster planning with shelter partners (states 96%, territories 83%, p = 0.564). Few had shelter assessment procedures (states 53%, territories 50%, p = 1.000); or training in disaster shelter assessments (states 41%, 60% territories, p = 0.638). Knowledge or preparedness was not predicted by disaster risks, population size, and jurisdiction type in neither model. Knowledge: hurricane (Adjusted OR 0.69, 95% C.I. 0.06-7.88); earthquake (OR 0.82, 95% C.I. 0.17-4.06); and both risks (OR 1.44, 95% C.I. 0.24-8.63); preparedness model: hurricane (OR 1.91, 95% C.I. 0.06-20.69); earthquake (OR 0.47, 95% C.I. 0.7-3.17); and both risks (OR 0.50, 95% C.I. 0.06-3.94). Environmental health deficiencies documented in shelter assessments occurred mostly in: sanitation (30%); facility (17%); food (15%); and sleeping areas (12%); and during ice storms and tornadoes. More research is needed in the area of environmental health assessments of disaster shelters, particularly, in those areas that may provide better insight into the living environment of all shelter occupants and potential effects in disaster morbidity and mortality. Also, to evaluate the effectiveness and usefulness of these assessments methods and the data available on environmental health deficiencies in risk management to protect those at greater risk in shelter facilities during disasters

Modelo de toma de decisiones para la selección del sistema de propulsión

History it has become evident that the military industry and its thriving action has generated change and development in different areas, and it is to be expected that a project as ambitious as the Strategic Surface Platform - PES focuses on the impact that internal combustion systems can generate in the design, therefore an evaluation model is developed for the selection of the propulsion system of the platform, which was based on the life cycle cost and performance of the main mechanical equipment, providing an additional tool for decision making. The cost side was estimated by breaking down the ROM (Rough Order of Magnitude) acquisition costs, maintenance costs and fuel and lubricant consumption costs, which leaves the performance side evaluated under the technical characteristics, considering the criteria of performance, reliability, delivered power and installation footprint; without leaving aside the mandatory requirements such as IMO TIER III gas emissions, reduction of the acoustic signature and the use of redundancy.A través de la historia se ha hecho evidente cómo la industria militar y su pujante accionar ha generado cambio y desarrollo en las diferentes áreas, y es de esperar que un proyecto tan ambicioso como lo es la Plataforma Estratégica de Superficie – PES se enfoque en el impacto que los sistemas de combustión interna pueden generar en el diseño, por lo anterior se desarrolla un modelo de evaluación para la selección del sistema de propulsión de la plataforma, el cual fue basado en el costo del ciclo de vida y el desempeño de los equipos mecánicos principales, brindando una herramienta adicional para la toma de decisiones. La arista del costo se estimó desglosando los costos de adquisición del tipo ROM (Rough Order of Magnitude), costos de mantenimiento y costos de consumo de combustible y lubricante, lo que deja la arista de desempeño evaluada bajo las características técnicas, considerando los criterios de rendimiento, confiabilidad, potencia entregada y huella de instalación; sin dejar a un lado los requisitos de obligatorio cumplimiento como lo son las emisiones de gases IMO TIER III, la reducción de la firma acústica y el empleo de la redundancia

Predicting interactions between common dolphins and the pole-and-line tuna fishery in the Azores

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in PLoS ONE 11 (2016): e0164107, doi:10.1371/journal.pone.0164107.Common dolphins (Delphinus delphis) are responsible for the large majority of interactions with the pole-and-line tuna fishery in the Azores but the underlying drivers remain poorly understood. In this study we investigate the influence of various environmental and fisheries-related factors in promoting the interaction of common dolphins with this fishery and estimate the resultant catch losses. We analysed 15 years of fishery and cetacean interaction data (1998–2012) collected by observers placed aboard tuna fishing vessels. Dolphins interacted in less than 3% of the fishing events observed during the study period. The probability of dolphin interaction varied significantly between years with no evident trend over time. Generalized additive modeling results suggest that fishing duration, sea surface temperature and prey abundance in the region were the most important factors explaining common dolphin interaction. Dolphin interaction had no impact on the catches of albacore, skipjack and yellowfin tuna but resulted in significantly lower catches of bigeye tuna, with a predicted median annual loss of 13.5% in the number of fish captured. However, impact on bigeye catches varied considerably both by year and fishing area. Our work shows that rates of common dolphin interaction with the pole-and-line tuna fishery in the Azores are low and showed no signs of increase over the study period. Although overall economic impact was low, the interaction may lead to significant losses in some years. These findings emphasize the need for continued monitoring and for further research into the consequences and economic viability of potential mitigation measures.This work was funded by Fundação para a Ciência e a Tecnologia (FCT) and DRCT/SRCTE, though FEDER, the Competitiveness Factors Operational (COMPETE), QREN European Social Fund, the Portuguese Ministry for Science and Education, under research projects TRACE (PTDC/MAR/74071/2006), FCT Exploratory Project (IF/00943/2013/CP1199/CT0001), and MAPCET (M2.1.2/F/012/2011). We acknowledge the support of Fundação para a Ciência e Tecnologia (FCT), through the strategic project UID/MAR/04292/2013 granted to MARE. We thank the Azorean Regional Government for funding POPA, the Ship-owners Association and the Association of the Tuna Canning Industries for their support to the program. MJC was supported by a DRCT doctoral grant (M3.1.2/F/008/2009). MAS was supported by POPH, QREN, European Social Fund and Portuguese Ministry for Science and Education, through an FCT Investigator grant (IF/00943/2013)

From algebras to objects : generation and composition

This paper addresses objectification, a formal specification technique which inspects the potential for object-orientation of a declarative model and brings the 'implicit objects' explicit. Criteria for such objectification are formalized and implemented in a runnable prototype tool which embeds Vdm-sl into Vdm++. The paper also includes a quick presentation of a (coinductive) calculus of such generated objects, framed as generalised Moore machines.Fundação para a Ciência e a Tecnologia (FCT

Fluência e durabilidade de elementos de betão armado reforçados com laminados de cfrp pela técnica NSM

O presente trabalho teve como objetivo avaliar o efeito da fluência no comportamento a longo prazo e durabilidade de estruturas de betão armado reforçadas com laminados de CFRP de acordo com a técnica NSM. Para tal foi desenvolvido um programa experimental constituído por lajes e ensaios de arranque em flexão, todos sujeitos a um carregamento constante e às seguintes condições ambientais: (i) ambiente de laboratório; (ii) imersão em água; (iii) imersão em água com NaCl; e, (iv) ciclos molhagem/secagem em água com NaCl. Nos ensaios de arranque verificou-se que o efeito de fluência na resistência mecânica foi praticamente negligenciável. As lajes apresentaram um efeito de fluência pronunciado, apesar de este ter sido desacelerado para os ambientes envolvendo submersão

Behaviour of concrete elements strengthened with near surface mounted CFRP strips under thermal cycles

The present work intends to contribute for the knowledge on durability performance of the near-surface mounted (NSM) strengthening technique, which is an issue that still requires significant research effort. For that purpose, an experimental program was developed using cubic pullout and slab specimens strengthened with NSM carbon fiber reinforced polymer (CFRP) strips. These specimens were submitted to thermal cycles in order to study the effect of this environmental action on the effectiveness of the NSM technique. The thermal cycles were defined according to the EN 13687-3 standard. After being submitted to this action during up to eight months, the specimens were monotonically tested up to failure using four-point bending and pullout direct test configurations for slabs and cubic specimens, respectively. To compare the performance of these specimens with non-aging ones, control specimens were also tested. The obtained results indicate that the loading capacity of the slabs and damage mechanism were not affected by thermal cycles. Nevertheless, the bond strength increased with the number of thermal cycles. Therefore, these results suggest that the concrete elements strengthened with CFRP NSM technique are not susceptible to temperature in a range of -15°C to 60°C.FCT -Federación Española de Enfermedades Rara