Canal de Experiencias Hidrodinámicas de El Pardo (Spain)

Chronic treatment with nonsteroidal antiinflammatory drugs (NSAIDs) has been associated with a reduced risk of colorectal cancer, but less information is available on the relationship between NSAIDs and colorectal adenoma. We carried out a population-based cohort study with nested case-control analysis to determine the association between the use of aspirin and individual NSAIDs and the risk of colorectal adenoma. The General Practice Research Database in the United Kingdom was the source population. We followed 943,903 persons who were 40-79 years of age and free of colorectal adenoma or other cancer at baseline, which varied between January 1994 and September 1997. There were 1,864 incident cases of colorectal adenoma, for an incidence rate of 6.8 per 10,000 person-years. Compared with non-users, long-term users (1 year and more) of nonaspirin NSAIDs had a 40% decreased risk of colorectal adenoma (relative risk = 0.6; 95% confidence interval = 0.4-0.9). Long-term NSAID use was still associated with a reduced risk 1 year after stopping NSAID treatment. Use of most individual NSAIDs conferred a reduced risk. The risk of developing colorectal adenoma was reduced in long-term users of aspirin at doses of 300 mg daily (relative risk = 0.6; 95% confidence interval = 0.4-1.0), but reduced risk was not evident with daily doses of 75 and 150 mg aspirin. These results add further support to the value of NSAIDs as a candidate for primary prevention of colorectal tumors.

The introduction of the energy efficiency design index (EEDI), which is applicable for various types of new-built ships after January 1,2013, raised concerns regarding the sufficiency of propulsion power and steering devices to maintain maneuverability in adverse conditions. This was the motivation for the initiation of the EU research project SHOPERA (Energy Efficient Safe SHip OPERAtion, 2013–2016, http://www.shopera.org). The aim of this article is the development of suitable methods, tools, and guidelines to effectively address the above concerns and to enable safe and green shipping. Within the framework of SHOPERA, a comprehensive experimental program of more than 1300 different model tests for three ship hulls of different geometry and hydrodynamic characteristics has been conducted by four leading European maritime experimental research institutes: MARINTEK, Norway; CEHIPAR, Spain; Technische Universität Berlin, Germany; and Flanders Hydraulics Research, Belgium. The tested hull types refer to two public domain designs, namely the KVLCC2 tanker and the Duisburg Test Case (DTC) container ship, as well as to a small RoPax ferry design, which is a proprietary hull design of a member of the SHOPERA consortium. The conducted tests were distributed among the four research institutes to benefit from the unique possibilities of each facility and to gain added value by establishing data sets for the same hull model and test type at different under keel clearances. This article presents the scope of the SHOPERA model test program for the two public domain hull models—the KVLCC2 and the DTC. The main particulars and loading conditions for the two vessels as well as the experimental setup is provided to support the interpretation of the experimental data that is presented. The focus lies on the added resistance and drift forces at zero and moderate forward speed, propulsion, and rudder force tests in waves and the assessment of maneuverability of ships in waves, as compared to calm water conditions.

A reliability analysis is presented of a circular tunnel face driven by a pressurized shield in a highly fractured Hoek–Brown (HB) rock mass. A limit analysis approach is employed to define a limit state function (LSF) based on an advanced rotational mechanism. The objective is to analyze how different reliability methods, different assumptions about distribution types and correlation structures of the random variables, and different tunnel sizes and support pressures influence the computed reliability results. Results indicate that the reliability method has a limited influence on reliability results, hence suggesting that the LSF is not highly nonlinear and that a computationally efficient method can be employed; and that all random variables under consideration are resistance variables, with their assumed distribution types and correlation structures having a significant effect on the reliability results. This emphasizes the importance of an adequate characterization of geotechnical uncertainties for practical applications. This also confirms that the reliability of tunnel face stability increases significantly as the face support increases or the tunnel diameter decreases.

Large size ships have a very flexible construction resulting in low resonance frequencies of the structural eigen-modes. This feature increases the dynamic response of the structure on short period waves (springing) and on impulsive wave loads (whipping). This dynamic response in its turn increases both the fatigue damage and the ultimate load on the structure; these aspects illustrate the importance of including the dynamic response into the design loads for these ship types. Experiments have been carried out using a segmented scaled model of a container ship in a Seakeeping Basin. This paper describes the development of the model for these experiments; the choice was made to divide the hull into six rigid segments connected with a flexible beam. In order to model the typical feature of the open structure of the containership that the shear center is well below the keel line of the vessel, the beam was built into the model as low as possible. The model was instrumented with accelerometers and rotation rate gyroscopes on each segment, relative wave height meters and pressure gauges in the bow area. The beam was instrumented with strain gauges to measure the internal loads at the position of each of the cuts. Experiments have been carried out in regular waves at different amplitudes for the same wave period and in long crested irregular waves for a matrix of wave heights and periods. The results of the experiments are compared to results of calculations with a linear model based on potential flow theory that includes the effects of the flexural modes. Some of the tests were repeated with additional links between the segments to increase the model rigidity by several orders of magnitude, in order to compare the loads between a rigid and a flexible model.

BACKGROUND: Ischaemic heart disease (IHD) can be excluded in the majority of patients with unspecific chest pain. The remainder have what is generally referred to as non-cardiac chest pain, which has been associated with gastrointestinal, neuromusculoskeletal, pulmonary, and psychiatric causes. AIM: To assess morbidity and mortality following a new diagnosis of non-specific chest pain in patients without established IHD. DESIGN OF STUDY: Population-based cohort study with nested case-control analysis. SETTING: UK primary care practices contributing to the General Practice Research Database. METHOD: Patients aged 20-79 years with chest pain who had had no chest pain consultation before 2000 and no IHD diagnosis before 2000 or within 2 weeks after the index date were selected from the General Practice Research Database. The selected 3028 patients and matched controls were followed-up for 1 year. RESULTS: The incidence of chest pain in patients without established IHD was 12.7 per 1000 person-years. In the year following the index date, patients who had chest pain but did not have established IHD were more likely than controls to receive a first IHD diagnosis (hazard ratio [HR] = 18.2, 95% confidence interval [CI] = 11.6 to 28.6) or to die (HR = 2.3, 95% CI = 1.3 to 4.1). Patients with chest pain commonly had a history of gastro-oesophageal reflux disease (GORD; odds ratio [OR] = 2.0, 95% CI = 1.5 to 2.7) or went on to be diagnosed with GORD (risk ratio 4.5, 95% CI = 3.1 to 6.4). CONCLUSION: Patients with chest pain but without established IHD were found to have an increased risk of being diagnosed with IHD. Chest pain in patients without established IHD was also commonly associated with GORD.

Neste artigo, buscamos realizar uma síntese, uma tentativa de categorização e uma avaliação crítica dos principais modelos, metodologias e experiências de construção de indicadores de sustentabilidade, destacando a necessidade da verificação e do estabelecimento de parâmetros e critérios em sua moldagem. Na atualidade, as principais experiências desenvolvidas ao redor do mundo, podem ser classificadas em dois tipos: 1) os chamados sistemas de indicadores, que seguem, em sua grande maioria, modelos derivados do Livro Azul da Comissão de Desenvolvimento Sustentável da ONU; e 2) os indicadores síntese, que buscam, em uma única unidade, agregar dados de ordem econômica, biofísica, social e institucional. Dentre tais tipos de indicadores, verifica-se uma grande diversidade de abordagens, com diferentes ênfases. Discutimos neste artigo a capacidade de tais indicadores efetivamente se converterem em marcos estruturados e cumprirem o seu papel de municiar, induzir e fomentar políticas e decisões bem estruturadas e fundamentadas.

In this paper, the response of buildings to tunnelling-induced ground movements is studied with elastic and elastoplastic continuum solutions that consider the structure as an equivalent simple beam. A comparison is made between these simple solutions and centrifuge test data to provide insights into flexural and axial building deformations of low-rise bearing wall structures on strip foundations; the influence of wall openings and the foundation scheme on the equivalent beam bending stiffness is also addressed. Subsequently, the effects of structural continuity across greenfield sagging and hogging regions on tunnel–structure interaction are investigated. Finally, the continuum solutions are used to propose a modification factor formulation that accounts for the change in settlement trough shape (compared to the greenfield) due to soil–structure interaction. This formulation, for example, accounts for the change in transverse length of the hogging and sagging regions of a building due to soil–structure interaction, eliminating the need to divide the building at the greenfield inflection points when calculating modification factors. The proposed formulation, which is compared with numerical, experimental and field data from previous research, is shown to better predict flexural building deformations.

Abstract In the case of SPAR or semi-submersible platforms for floating wind turbines, it is beneficial in some cases to use heave plates that reduce their heave motion amplitude and/or tune their heave natural period. As part of the Hiprwind project, it was decided to study scale effects on the hydrodynamics of this element. To this aim, models of one leg of the platform, equipped with a heave plate without any reinforcements, were built. This model is a simplified representation of the actual one, which incorporates a vertical flap on the heave plate edge. The scales were 1:20, 1:27.6, and 1:45.45, with the former leading to added mass values of the order of 300 kg, becoming one of the largest models for which experiments with heave oscillations have been carried out. Decay tests starting from various amplitudes and forced oscillations tests for a range of frequencies and amplitudes were performed. It is shown in the paper that the influence of the scale factor on the hydrodynamic coefficients is weaker than the effect that the motion amplitude (characterized with the Keulegan–Carpenter (KC) number produces in them. This result is relevant because the selection of a representative KC is an important and somewhat arbitrary aspect to be set in the linear potential simulation codes in order to add viscous damping. What has been shown herein is that a right selection of KC has a larger impact on the models than the uncertainties due to eventual scale effects in the heave-plates dynamics.

Shared mooring can potentially be a cost-reduction factor for future floating wind farms. To assess the effect of shared mooring on the response dynamics of floating wind turbines (FWTs), experiments have been conducted for two spar FWTs with a shared mooring configuration and for a single spar FWT with catenary mooring, both at a scale of 1:47. Various regular and irregular wave conditions were tested and only one wave heading was considered. From the test results, the response amplitude operators and response spectra of platform motions and statistics of mooring tensions are compared for the two configurations. In the extreme wave condition, the shared mooring configuration leads to a 40% increase in the platform surge motion compared with the single spar FWT. Still, the absolute offset is within allowable limits prescribed by power cables. The fairlead tensions of the anchor lines are not significantly increased in the shared mooring configurations, but the shared line shows extreme tension peak events that are seldom present in the anchor lines. This study demonstrates the technological promises and challenges of a shared mooring system from an experimental perspective. Results and videos are made available and can be used to validate numerical models.

Targeted knock-in (KI) can be achieved in embryos by clustered regularly interspaced short palindromic repeats (CRISPR)-assisted homology directed repair (HDR). However, HDR efficiency is constrained by the competition of nonhomologous end joining. The objective of this study was to explore whether CRISPR-assisted targeted KI rates can be improved in bovine embryos by exposure to the HDR enhancer RS-1. In vitro produced zygotes were injected with CRISPR components (300 ng/µl Cas9 messenger RNA and 100 ng/µl single guide RNA against a noncoding region) and a single-stranded DNA (ssDNA) repair template (100 ng/µl). ssDNA template contained a 6 bp XbaI site insert, allowing targeted KI detection by restriction analysis, flanked by 50 bp homology arms. Following microinjection, zygotes were exposed to 0, 3.75, or 7.5 µM RS-1 for 24 hr. No differences were noted between groups in terms of development or genome edition rates. However, targeted KI rates were doubled in the group exposed to 7.5 µM RS-1 compared to the others (52.8% vs. 25% and 23.1%, for 7.5, 0, and 3.75 µM, respectively). In conclusion, transient exposure to 7.5 µM RS-1 enhances targeted KI rates resulting in approximately half of the embryos containing the intended mutation, hence allowing direct KI generation in embryos.

Shared mooring brings potential cost benefits to a floating wind farm. In such a wind farm, adjacent floaters are connected by shared lines and the total number of mooring lines is reduced. This paper presents an experimental study on a dual-spar floating offshore wind farm. In the first configuration, two spars are connected by a shared line. In the second configuration, a clump weight is added to the shared line. Irregular wave tests are performed for both configurations under operational and extreme wave conditions. The platform motions of one wind turbine and the mooring tension are measured during the tests. The influence of the added clump weight is found to be insignificant in the operational wave conditions. Under extreme waves, the added clump weight results in smaller platform motions in the wave direction and reduced tension oscillations in all mooring lines. With the additional clump weight, the extreme mooring tension in the shared line can decrease by 30% and fewer snap loading events occur, but the extreme tension in single lines can increase by 6%. This study contributes to an improved understanding of shared mooring systems and facilitates the development of model test methods for floating wind farms.

Abstract A method is proposed for the estimation of ground‐water recharge rates in karstic aquifers by the analysis of hydrograph recession and multiple regression. Several methods are mentioned of estimating recharge rates by recession analysis of discharge at springs and from which recharge records can be obtained. Recharge (R) can also be estimated from precipitation (P) and air temperature (T) by the formula R = aP – bT + c. The components a, b, and c were derived from time‐series data of four aquifers in the Mediterranean zone. For the first two of these aquifers, the recharge was calculated by integrating spring discharge between two points with the equal flow. For the third aquifer, a more elaborate calculation was based on multiple aquifers with semi logarithmic depletions. A numerical model, SIMERO, was used for the fourth. Given the appropriate correlation coefficients, the procedure is advantageous because of its simplicity. Limiting relationships between P and T are deduced.

Highway concessions are becoming quite popular all around the world as a means to promote private participation in the management and financing of public infrastructure. The congestion problems caused by the limited capacity of the road infrastructure networks in many metropolitan areas are prompting public authorities to adopt the concession approach to improve highway capacity, while at the same time implementing a congestion pricing approach. This paper describes and assesses the case study of a toll highway concession program, recently implemented in the city of Madrid, to build four radial toll highways intended to reduce congestion and at the same time to raise revenues to fund the new infrastructure. The concessions, which started their operations in 2003 and 2004, have not worked as well as expected. There are several reasons for this. The most important one is that they managed to capture only a small share of the traffic in the corridor. This has caused serious financial problems to the concessionaires, who are now on the verge of bankruptcy. This paper analyses both the reasons behind the government’s adoption of the concession approach, and the reasons why this approach ultimately proved unsuccessful. On the basis of the results of this case study, we offer a set of recommendations for policy makers when considering the use of toll highway concession contracts in metropolitan areas

Abstract A methodology for the study of thermal waters in unexploited aquifers is proposed. This methodology has been applied to the Alhama Aquifer, which is the origin of the most important thermal springs of the Iberian Peninsula. A conceptual model was made of the aquifer by integrating data such as (1) the geometry at depth (on the basis of deep geophysics) and at the surface (from conventional geological maps); (2) hydrographic analysis of the aquifer discharge; (3) a study of the recharge by classic hydrometeo‐rological methods; and (4) conventional and isotopic hydrochemistry. In addition to the hydraulic regional parameters it provides, the model explains the origin of the Alhama springs in terms of simple circulation at a depth of some 900 m and a normal geothermal gradient (3°C/100 m), with no requirement of contact with a source of heat at the bottom of the aquifer.

El clickbait es una estrategia utilizada en los medios digitales, que busca llamar la atención a través de los titulares, apelando a las emociones y a la curiosidad de los lectores para que cliquen en la noticia. Para indagar en este fenómeno, se procede a estudiar a través de una metodología cualitativa y cuantitativa los titulares de las portadas de los cuatro principales diarios nativos digitales en España durante una semana (n=2505): El Confidencial, El Español, eldiario.es y Ok Diario. Entre los resultados de la investigación destaca una presencia alta de titulares que contienen clickbait (48% en el cómputo global, ascendiendo al 69,5% en las soft news), siendo las modificaciones de morfosintaxis de las oraciones el recurso más utilizado. Se discuten estos hallazgos en el marco de las dinámicas de la comunicación digital, cuestionando si el clickbait, como fenómeno extendido en los diarios nativos digitales, puede llevar a un mayor número de visualizaciones en sus páginas, pero en detrimento de la calidad de las informaciones publicadas.

One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Such properties condition the behaviour of reinforced concrete structures and must be taken into account when re-engineering corroded members, for even the analytical approach itself may be determined on these grounds. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when exposed to accelerated corrosion; the results serve as a basis for a discussion of the most suitable methodology for structural analysis.

The Energy Efficiency Design Index (EEDI), introduced by the IMO [1] is applicable for various types of new-built ships since January 2013. Despite the release of an interim guideline [2], concerns regarding the sufficiency of propulsion power and steering devices to maintain manoeuvrability of ships in adverse conditions were raised. This was the motivation for the EU research project SHOPERA (Energy Efficient Safe SHip OPERAtion, 2013–2016 [3–6]). The aim of the project is the development of suitable methods, tools and guidelines to effectively address these concerns and to enable safe and green shipping. Within the framework of SHOPERA, a comprehensive test program consisting of more than 1,300 different model tests for three ship hulls of different geometry and hydrodynamic characteristics has been conducted by four of the leading European maritime experimental research institutes: MARINTEK, CEHIPAR, Flanders Hydraulics Research and Technische Universität Berlin. The hull types encompass two public domain designs, namely the KVLCC2 tanker (KRISO VLCC, developed by KRISO) and the DTC container ship (Duisburg Test Case, developed by Universität Duisburg-Essen) as well as a RoPax ferry design, which is a proprietary hull design of a member of the SHOPERA consortium. The tests have been distributed among the four research institutes to benefit from the unique possibilities of each facility and to gain added value by establishing data sets for the same hull model and test type at different under keel clearances (ukc). This publication presents the scope of the SHOPERA model test program for the two public domain hull models — the KVLCC2 and the DTC. The main particulars and loading conditions for the two vessels as well as the experimental setup is provided to support the interpretation of the examples of experimental data that are discussed. The focus lies on added resistance at moderate speed and drift force tests in high and steep regular head, following and oblique waves. These climates have been selected to check the applicability of numerical models in adverse wave conditions and to cover possible non-linear effects. The obtained test results with the KVLCC2 model in deep water at CEHIPAR are discussed and compared against the results obtained in shallow water at Flanders Hydraulics Research. The DTC model has been tested at MARINTEK in deep water and at Technische Universität Berlin and Flanders Hydraulics Research in intermediate/shallow water in different set-ups. Added resistance and drift force measurements from these facilities are discussed and compared. Examples of experimental data is also presented for manoeuvring in waves. At MARINTEK, turning circle and zig-zag tests have been performed with the DTC in regular waves. Parameters of variation are the initial heading, the wave period and height.

Most of the computational works on nasal airflow up to date have assumed incompressibility, given the low Mach number of these flows. However, for high temperature gradients, the incompressibility assumption could lead to a loss of accuracy, due to the temperature dependence of air density and viscosity. In this article we aim to shed some light on the influence of this assumption in a model of calm breathing in an Asian nasal cavity, by solving the fluid flow equations in compressible and incompressible formulation for different ambient air temperatures using the OpenFOAM package. At low flow rates and warm climatological conditions, similar results were obtained from both approaches, showing that density variations need not be taken into account to obtain a good prediction of all flow features, at least for usual breathing conditions. This agrees with most of the simulations previously reported, at least as far as the incompressibility assumption is concerned. However, parameters like nasal resistance and wall shear stress distribution differ for air temperatures below [Formula: see text]C approximately. Therefore, density variations should be considered for simulations at such low temperatures.

Abstract The hydrodynamic processes and mechanisms involved in rain infiltration and recharge in local areas of karst terrain can be identified and quantified by using measurements of the seepage of cave stalactites. Detailed measurements of the seepage of stalactites in seven caves located in an area close to the land surface, or the subcutaneous area of the karst, show a diversity of complex factors involved in infiltration: type of precipitation (rain or snow), air temperature, soil type and thickness, etc., which give rise to larger or smaller variations of flow in the espeleothem hydrographs. In some cases, no explanation can be found for the response of stalactites to rainfall, while in others there is a relationship between outer atmospheric parameters and the recharge represented by the stalactite drip. Romperopas Cave (Spain) has both a rapid and a basic flow, with hydrograph recessions similar to those observed in other caves. Water seepage in this cave varies greatly both in space and in time. The infiltration in Altamira Cave (Spain) was calculated and a multiple regression was found between infiltration, rain and outside air temperature. In other cases, the balance of the water on the soil is responsible for the seepage. Thus, a precipitation runoff numerical model that simulated the stalactite hydrographs could be applied to the Baradla and Beké Caves (Hungary). The complex properties of the ground, which are required for other flow numerical models for the unsaturated zone, were not taken into consideration.

This study first examines the minimum power requirements of a tanker according to the IMO 2013 IMO. 2013. Interim guidelines for determining minimum propulsion power to maintain the maneuverability in adverse conditions. London: International Maritime Organization. [Google Scholar] Interim Guideline (IMO 2013 IMO. 2013. Interim guidelines for determining minimum propulsion power to maintain the maneuverability in adverse conditions. London: International Maritime Organization. [Google Scholar]). For the estimation of the added resistance in waves a recently introduced semi-empirical method is used. Secondly, the influence of the increase in surface roughness of the hull and propeller due to fouling is investigated, reflecting the actual condition of a ship in service. The results show that even if ships are fulfilling the IMO 2013 IMO. 2013. Interim guidelines for determining minimum propulsion power to maintain the maneuverability in adverse conditions. London: International Maritime Organization. [Google Scholar] Guideline, they may become unsafe in operation. Lastly, the uncertainties involved in the assessment procedure are discussed. The investigation conducted is particularly of interest for the assessment of the safety of ships now being idle or used as floating storage due to the impact of the pandemic COVID-19 on the world economy, while they are expected to go again into service once the demand for transport recovers.