‘Together … for only a moment’ British newspaper constructions of altruistic non-commercial surrogate motherhood

Objectives: To explore how national altruistic surrogacy is framed in a representative selection of the British press. Methods: A study of 90 British national newspaper articles was carried out using the Lexis-Nexis data base to search for articles on altruistic surrogacy. Content analysis of gain, loss, neutral frames and high or low alarm and vulnerability frames in the titles and the body of the text was carried out. The type of construction used in the article content was also analysed. Data were coded and consensus reached using a coding strategy specifically developed for the purposes of this study. Results: Titles and content were predominantly loss, high alarm and high vulnerability framed. The content was also gain framed, and written with a focus on the social and legal aspects differentially between the newspaper types. Discussion: The tabloid press emphasizes social issues, and the middle market and serious press focus on legal issues of altruistic surrogacy. Selectively framed and reinforced information provided by the different newspapers, reflect the different readership, with Tabloid readers likely to be, surrogates (mostly from lower socioeconomic strata) and serious/ middle-market readers likely to be commissioning parents (mostly professionals)

Complete framework of wind-vehicle-bridge interaction with random road surfaces

The risk of vehicle accidents and discomfort under wind actions is key in the serviceability assessment of long-span bridges. This paper presents a complete wind-vehicle-bridge interaction (W-VBI) framework in which the pavement irregularities are simulated as random surfaces that include the bridge joints instead of traditional one-dimensional (1D) road profiles. The methodology includes a new approach to assess the safety and comfort of all the users of the bridge, including those in the vehicles and on the deck, and to account for the variability of the response. The application of the proposed W-VBI framework in the study of a long cable-stayed bridge demonstrated that the driving safety and the pedestrians’ comfort cannot be based on the analysis of a single record, and guidance is proposed to obtain results with statistical significance. Moreover, it is observed for the first time that 1D road irregularity models can significantly underpredict the risk of discomfort and of driving instabilities in bridges subjected to crosswinds. Finally, the direct connection between the quality of the road and the comfort in the vehicles is clearly established, which has potential implications on pavement monitoring programmes

Simulating the Response of Free-Standing Rocking Rigid Blocks using Abaqus/Standard

This work presents detailed finite element models developed in Abaqus/Standard to study the rocking response of free-standing rigid blocks, which is characterised by the alternation of impacts between the block and the foundation that suddenly change the contact point between the two members. Nonlinear dynamic analysis with implicit time integration is carried out to study rocking initiation (uplift) and rocking attenuation (at impact) of free-standing rigid blocks with different slenderness under pulse-type motions. The attenuation effects are further studied by allowing the block to rock freely on the foundation. Solid homogenous sections are analysed with fully integrated 4-node plane stress quadrilateral elements (CPS4) for the block and the equivalent reduced integration elements (CPS4R) for the foundation. Rigid body constraints are used to refer the motion of each body to the respective centre of gravity. Contact is treated using the small-sliding formulation and the resulting system of equations of dynamics is solved by means of the Abaqus/Standard HHT algorithm, with the value of alpha that provides the maximum numerical dissipation. A sensitivity analysis is conducted for the time incrementation and mesh element size. Large time steps lead to higher attenuation of rocking movement due to the increment of the contact constraint discontinuity work (ALLCCDW), an energy component which highly influences rocking movement. However, smaller values of the step time yield very accurate results in comparison with the analytical solution. The element size sensitivity analysis revealed that the rocking initiation is generally well captured, but the coarse mesh results in inaccurate capture of the instant at which impact occurs and unrealistic attenuation of the rocking response. On the contrary, the fine mesh (defined as 1% of the corresponding contact surface) seems to capture well the rigid rocking response. These suggest that the selection of the analysis parameters is crucial to capture the desired response of free-standing rigid blocks

Thick-medium model of transverse pattern formation in optically excited cold two-level atoms with a feedback mirror

We study a pattern-forming instability in a laser-driven optically thick cloud of cold two-level atoms with a planar feedback mirror. We develop a theoretical model, enabling a full analysis of transverse patterns in a medium with saturable nonlinearity, taking into account diffraction within the medium, and both the transmission and reflection gratings. The focus of the analysis is on the combined treatment of nonlinear propagation in a diffractively and optically thick medium and the boundary condition given by feedback. We demonstrate explicitly how diffraction within the medium breaks the degeneracy of Talbot modes inherent in thin-slice models. We predict the existence of envelope curves bounding all possible pattern-formation thresholds and illustrate their interaction with threshold curves by experimental observation of a sudden transition between length scales as mirror displacement is varied

New Mineral Names,

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