Dynamic behaviour and seismic response of structures isolated with low shape factor bearings

This study investigates the mechanical behaviour of laminated elastomeric bearings with a low shape factor (LSF) and the dynamic response of structures mounted on them. Axial loads have a significant influence on the mechanical behaviour of the LSF bearings. Most of the existing theories and mechanical models for laminated bearings cannot be employed for LSF bearings because they disregard the important effects of axial shortening and bulging of the rubber layers on the horizontal bearing stiffness. In this study, a simplified model originally developed for slender rubber blocks is employed for describing the mechanical behaviour of LSF bearings, and validated against the experimental results on low-damping LSF bearings manufactured and tested at Tun Abdul Razak Research Center (TARRC). The proposed model is then used to simulate the seismic response of a structural prototype mounted on the low-damping LSF bearings and tested at University of Naples Federico II on a shaking table under horizontal seismic input. Further analyses are carried out to evaluate how the bearing shape factor affects the dynamic and seismic response of the prototype. The study provides some useful insight into the complex mechanical behaviour of LSF bearings and of structures mounted on them

Aproximación al conocimiento del proceso de erosión del suelo en el Chaco Oriental

Preliminar data obtained through periodical gauging Controls of the main rivers coming from the hydrographic basins inserted in the subregión of the Eastern Chaco, are reported. Physical and Chemical characteristics of the water quality were quantified and then correlated with the available data, related in the edaphic conditions to estimate, approximately, the interrelations existing between the soil tipology and the elements being moved by the hydric erosión. They were evaluated according with their role played in the water composition, in accordance with the different hydrologic situation and soil management. The hypothesis which preconizes that the effluent from a basin represents the landscape heterogenity and dinamism, is assumed to be valid.Preliminar data obtained through periodical gauging Controls of the main rivers coming from the hydrographic basins inserted in the subregión of the Eastern Chaco, are reported. Physical and Chemical characteristics of the water quality were quantified and then correlated with the available data, related in the edaphic conditions to estimate, approximately, the interrelations existing between the soil tipology and the elements being moved by the hydric erosión. They were evaluated according with their role played in the water composition, in accordance with the different hydrologic situation and soil management. The hypothesis which preconizes that the effluent from a basin represents the landscape heterogenity and dinamism, is assumed to be valid

Erosión fluvial en la cuenca del río Bermejito (Prov. del Chaco, Argentina)

Size, distribution and longitudinal changes of suspended load was analized in Bermejito River, located in the Chaco subtropical plain. Temporal variability was compared with hydrometric levels and rainfalls in selectionated areas of the drainage basin. Field activities were carried out in three sections with free runoff and one section with reduced velocity for natural causes. Sampies were taken with an instantaneous point-sampler placed at 20X, 60X and 80X of depth, through equally spaced verticals across the sections. Laboratory procedures ineludes filtering through 62 a open sieve and subsequently through filters with 4 a and 0,45a por es, for retention sand, sllt and clay fractions, respectively. Mean textural composition in the free-runoff sections comprised silts (95X) and clays (5X). Concentration had an homogeneous distribuíiuon in the flow, owing to the turbulence effect. Longitudinal changes were related with the transport capacity of the water course. Rainfall determined a quick increment of the suspended sediment concentration by wash-load incorporationowing to the scarce vegetal protection. The restrict runoff section had fewer suspended sediment concentration and a greater clay fraction proportion. Sediment yield was estimated in 12.4 tn/km'/yr and the present erosión rate was calculated in about 5 mm for each 1000 years.Size, distribution and longitudinal changes of suspended load was analized in Bermejito River, located in the Chaco subtropical plain. Temporal variability was compared with hydrometric levels and rainfalls in selectionated areas of the drainage basin. Field activities were carried out in three sections with free runoff and one section with reduced velocity for natural causes. Sampies were taken with an instantaneous point-sampler placed at 20X, 60X and 80X of depth, through equally spaced verticals across the sections. Laboratory procedures ineludes filtering through 62 a open sieve and subsequently through filters with 4 a and 0,45a por es, for retention sand, sllt and clay fractions, respectively. Mean textural composition in the free-runoff sections comprised silts (95X) and clays (5X). Concentration had an homogeneous distribuíiuon in the flow, owing to the turbulence effect. Longitudinal changes were related with the transport capacity of the water course. Rainfall determined a quick increment of the suspended sediment concentration by wash-load incorporationowing to the scarce vegetal protection. The restrict runoff section had fewer suspended sediment concentration and a greater clay fraction proportion. Sediment yield was estimated in 12.4 tn/km'/yr and the present erosión rate was calculated in about 5 mm for each 1000 years

Introducción al estudio de sedimentos fluviales de llanura

Con la finalidad de conservar los ambientes fluviales en sus condiciones prístinas, diversas variables deben ser analizadas. Los sedimentos son unas de las variables más importantes dado que influye potencialmente la morfología del paisaje, la química de las aguas y la dinámica biológica de los cursos de agua. El presente trabajo presenta una introducción de fácil interpretación sobre las características de mayor relevancia ambiental de los sedimentos, sus interacciones y su dinámica en áreas de llanura, de tal modo que los científicos que trabajen en ambientes fluviales de llanura puedan tener una primera aproximación para una correcta interpretación ambiental del rol de los sedimentos. Las características aquí mencionadas incluyen clasificación granulométrica, transporte y mineralogía. En las últimas décadas aumentaron las investigaciones sobre estudios orientados a la evaluación de ambientes fluviales con el objeto de mejorar el conocimiento de su estructura y dinámica, para así poder trabajar en mantenerlos lo más cercano posible a sus condiciones prístinas, mediante una correcta gestión de los recursos involucrados.En el presente trabajo se realiza una breve introducción a los fundamentos que rigen el estudio de los sedimentos en ambientes fluviales de llanura, una de las variablesa tener en cuenta, junto a las características físicas y químicas de las aguas, así como de los suelos, cuando se pretende realizar un estudio del estado y evolución de un ambiente. Una correcta interpretación de los ambientes de llanura resulta indispensable para los científicos que trabajan en la región, dado que la Llanura Chacopampeana y la región Mesopotámica, son áreas caracterizadas por la baja pendiente.

Risk factors for bronchiolitis hospitalization during the first year of life in a multicenter Italian birth cohort

BACKGROUND: Respiratory Syncytial Virus (RSV) is one of the main causes of respiratory infections during the first year of life. Very premature infants may contract more severe diseases and 'late preterm infants' may also be more susceptible to the infection. The aim of this study is to evaluate the risk factors for hospitalization during the first year of life in children born at different gestational ages in Italy. METHODS: A cohort of 33-34 weeks gestational age (wGA) newborns matched by sex and age with two cohort of newborns born at 35-37 wGA and > 37 wGA were enrolled in this study for a three-year period (2009-2012). Hospitalization for bronchiolitis (ICD-9 code 466.1) during the first year of life was assessed through phone interview at the end of the RSV season (November-March) and at the completion of the first year of life. RESULTS: The study enrolled 2314 newborns, of which 2210 (95.5 %) had a one year follow-up and were included in the analysis; 120 (5.4 %) were hospitalized during the first year of life for bronchiolitis. Children born at 33-34 wGA had a higher hospitalization rate compared to the two other groups. The multivariate analysis carried out on the entire population associated the following factors with higher rates for bronchiolitis hospitalization: male gender; prenatal treatment with corticosteroids; prenatal exposure to maternal smoking; singleton delivery; respiratory diseases in neonatal period; surfactant therapy; lack of breastfeeding; siblings <10 years old; living in crowded conditions and/or in unhealthy households and early exposure to the epidemic RSV season. When analysis was restricted to preterms born at 33-34 wGA the following variables were associated to higher rates of bronchiolitis hospitalization: male gender, prenatal exposure to maternal smoking, neonatal surfactant therapy, having siblings <10 years old, living in crowded conditions and being exposed to epidemic season during the first three months of life. CONCLUSION: Our study identified some prenatal, perinatal and postnatal conditions proving to be relevant and independent risk factors for hospitalization for bronchiolitis during the first year of life. The combination of these factors may lead to consider palivizumab prophylaxis in Italy

Prenatal tobacco smoke exposure increases hospitalizations for bronchiolitis in infants

BACKGROUND: Tobacco smoke exposure (TSE) is a worldwide health problem and it is considered a risk factor for pregnant women's and children's health, particularly for respiratory morbidity during the first year of life. Few significant birth cohort studies on the effect of prenatal TSE via passive and active maternal smoking on the development of severe bronchiolitis in early childhood have been carried out worldwide. METHODS: From November 2009 to December 2012, newborns born at ≥ 33 weeks of gestational age (wGA) were recruited in a longitudinal multi-center cohort study in Italy to investigate the effects of prenatal and postnatal TSE, among other risk factors, on bronchiolitis hospitalization and/or death during the first year of life. RESULTS: Two thousand two hundred ten newborns enrolled at birth were followed-up during their first year of life. Of these, 120 (5.4%) were hospitalized for bronchiolitis. No enrolled infants died during the study period. Prenatal passive TSE and maternal active smoking of more than 15 cigarettes/daily are associated to a significant increase of the risk of offspring children hospitalization for bronchiolitis, with an adjHR of 3.5 (CI 1.5-8.1) and of 1.7 (CI 1.1-2.6) respectively. CONCLUSIONS: These results confirm the detrimental effects of passive TSE and active heavy smoke during pregnancy for infants' respiratory health, since the exposure significantly increases the risk of hospitalization for bronchiolitis in the first year of lif

Three-dimensional modelling of a very large river the Río Paraná

River hydrodynamicsBed roughness and flow resistanc

Lessons for Remote Post-earthquake Reconnaissance from the 14 August 2021 Haiti Earthquake

On 14th August 2021, a magnitude 7.2 earthquake struck the Tiburon Peninsula in the Caribbean nation of Haiti, approximately 150 km west of the capital Port-au-Prince. Aftershocks up to moment magnitude 5.7 followed and over 1,000 landslides were triggered. These events led to over 2,000 fatalities, 15,000 injuries and more than 137,000 structural failures. The economic impact is of the order of US$1.6 billion. The on-going Covid pandemic and a complex political and security situation in Haiti meant that deploying earthquake engineers from the UK to assess structural damage and identify lessons for future building construction was impractical. Instead, the Earthquake Engineering Field Investigation Team (EEFIT) carried out a hybrid mission, modelled on the previous EEFIT Aegean Mission of 2020. The objectives were: to use open-source information, particularly remote sensing data such as InSAR and Optical/Multispectral imagery, to characterise the earthquake and associated hazards; to understand the observed strong ground motions and compare these to existing seismic codes; to undertake remote structural damage assessments, and to evaluate the applicability of the techniques used for future post-disaster assessments. Remote structural damage assessments were conducted in collaboration with the Structural Extreme Events Reconnaissance (StEER) team, who mobilised a group of local non-experts to rapidly record building damage. The EEFIT team undertook damage assessment for over 2,000 buildings comprising schools, hospitals, churches and housing to investigate the impact of the earthquake on building typologies in Haiti. This paper summarises the mission setup and findings, and discusses the benefits, and difficulties, encountered during this hybrid reconnaissance mission

Factor Xa Generation by Computational Modeling: An Additional Discriminator to Thrombin Generation Evaluation

Factor (f)Xa is a critical enzyme in blood coagulation that is responsible for the initiation and propagation of thrombin generation. Previously we have shown that analysis of computationally generated thrombin profiles is a tool to investigate hemostasis in various populations. In this study, we evaluate the potential of computationally derived time courses of fXa generation as another approach for investigating thrombotic risk. Utilizing the case (n = 473) and control (n = 426) population from the Leiden Thrombophilia Study and each individual's plasma protein factor composition for fII, fV, fVII, fVIII, fIX, fX, antithrombin and tissue factor pathway inhibitor, tissue factor-initiated total active fXa generation was assessed using a mathematical model. FXa generation was evaluated by the area under the curve (AUC), the maximum rate (MaxR) and level (MaxL) and the time to reach these, TMaxR and TMaxL, respectively. FXa generation was analyzed in the entire populations and in defined subgroups (by sex, age, body mass index, oral contraceptive use). The maximum rates and levels of fXa generation occur over a 10- to 12- fold range in both cases and controls. This variation is larger than that observed with thrombin (3–6 fold) in the same population. The greatest risk association was obtained using either MaxR or MaxL of fXa generation; with an ∼2.2 fold increased risk for individuals exceeding the 90th percentile. This risk was similar to that of thrombin generation(MaxR OR 2.6). Grouping defined by oral contraceptive (OC) use in the control population showed the biggest differences in fXa generation; a >60% increase in the MaxR upon OC use. FXa generation can distinguish between a subset of individuals characterized by overlapping thrombin generation profiles. Analysis of fXa generation is a phenotypic characteristic which may prove to be a more sensitive discriminator than thrombin generation among all individuals