OC6 Phase I: Investigating the underprediction of low-frequency hydrodynamic loads and responses of a floating wind turbine

Phase I of the OC6 project is focused on examining why offshore wind design tools underpredict the response (loads/motion) of the OC5-DeepCwind semisubmersible at its surge and pitch natural frequencies. Previous investigations showed that the underprediction was primarily related to nonlinear hydrodynamic loading, so two new validation campaigns were performed to separately examine the different hydrodynamic load components. In this paper, we validate a variety of tools against this new test data, focusing on the ability to accurately model the low-frequency loads on a semisubmersible floater when held fixed under wave excitation and when forced to oscillate in the surge direction. However, it is observed that models providing better load predictions in these two scenarios do not necessarily produce a more accurate motion response in a moored configuration.The authors would like to acknowledge the support of the MARINET2 project (European Union’s Horizon 2020 grant agreement 731084), which supplied the tank test time and travel support to accomplish the testing campaign. The support of MARIN in the preparation, execution of the modeltests, and the evaluation of the uncertainties was essential for this study. MARIN’s contribution was partly funded by the Dutch Ministry of Economic Affairs through TKI-ARD funding programs. This work was authored in part by the National Renewable Energy Laboratory, operated by Alliance for Sustainable Energy, LLC, for the U.S. Department of Energy (DOE) under Contract No. DE-AC36- 08GO28308. Funding provided by the U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Wind Energy Technologies Office. The views expressed in the article do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains and the publisher, by accepting the article for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow others to do so, for U.S. Government purposes

Risk, reassurance and routine: a qualitative study of narrative understandings of the potential for HIV self-testing among men who have sex with men in England

BACKGROUND: HIV testing has seen a rapid evolution over the last decade with multiple modalities now in use globally. In recent years HIV self-testing (HIVST) has been legalised in the UK paving the way for further expansion of testing. Interventions are delivered in particular social contexts which shape uptake. It is therefore important to understand how novel interventions are likely to be received by their intended users. This study aims to understand how HIVST compliments existing testing strategies considered or adopted by men who have sex with men (MSM). We do this by analysing normative discourses surrounding HIV testing and their perceptions of HIVST's potential future roles. METHODS: Six focus group discussions (FGDs) were conducted with 47 MSM in London, Manchester and Plymouth. One focus group included only MSM who reported higher risk behaviours and one with those who had never tested for HIV. Data were analysed through a thematic framework analysis. RESULTS: Three main narratives for testing for HIV were identified: (i) testing in response to a specific risk event; (ii) as reassurance when there was a small amount of doubt or anxiety related to HIV; and (iii) in response to social norms perpetuated through peers, HIV community groups and the medical establishment to test regularly for HIV. HIVST had limited utility for men when testing in response to specific risk events except in the case of significant structural barriers to other testing opportunities. HIVST was considered to have utility when seeking reassurance, and was thought to be very useful when testing to satisfy the needs and expectations of others around regular testing. There was some ambivalence about the incursion of a clinical intervention into the home. CONCLUSIONS: HIVST following risk events will likely be limited to those for whom existing service provision is insufficient to meet immediate needs based on structural or personal barriers to testing. Obligations of biological citizenship are central to MSM's understanding of the utility of HIVST. In the context of discourses of biocitizenship, men perceive HIVST to have dual roles: firstly as a tool to manage (mild) anxiety around one's HIV status based on an acknowledgment of HIV vulnerability arising from being homosexually active. Secondly, HIVST is useful in complying with social norms and meeting the perceived demands of biomedicine

OC6 project Phase IV: Validation of numerical models for novel floating offshore wind support structures

\ua9 Copyright: This paper provides a summary of the work done within Phase IV of the Offshore Code Comparison Collaboration, Continued with Correlation and unCertainty (OC6) project, under International Energy Agency Wind Technology Collaboration Programme Task 30. This phase focused on validating the loading on and motion of a novel floating offshore wind system. Numerical models of a 3.6MW horizontal-axis wind turbine atop the TetraSpar floating support structure were compared using measurement data from a 1:43-Froude-scale test performed in the University of Maine\u27s Alfond Wind-Wave (W2) Ocean Engineering Laboratory. Participants in the project ran a series of simulations, including system equilibrium, surge offsets, free-decay tests, wind-only conditions, wave-only conditions, and a combination of wind and wave conditions. Validation of the models was performed by comparing the aerodynamic loading, floating support structure motion, tower base loading, mooring line tensions, and keel line tensions. The results show a relatively good estimation of the aerodynamic loading and a reasonable estimation of the platform motion and tower base fore-aft bending moment. However, there is a significant dispersion in the dynamic loading for the upwind mooring line. Very good agreement was observed between most of the numerical models and the experiment for the keel line tensions

Immunological Sex Differences in Socially Promiscuous African Ground Squirrels

Differences in how males and females respond to foreign antigens are common across taxa. Such sexual differences in the immune system are predicted to be greater in species with high promiscuity and sociality as these factors increase the likelihood of disease transmission. Intense sperm competition is thought to further this sexual dichotomy as increased investment in spermatogenesis likely incurs additional immunological costs. Xerus inauris, a ground squirrel found throughout southern Africa, is extremely social and promiscuous with one of the highest male reproductive investments among rodents. These life-history attributes suggest males and females should demonstrate a large dichotomy in immunity. Contrary to our prediction, we found no difference in spleen mass between the sexes. However, we did find significant biases in leukocyte types and red blood cell counts, possibly reflecting responses to parasite types. Among males, we predicted greater investments in spermatogenesis would result in reduced immunological investments. We found a negative association between testes and spleen size and a positive relationship between testes and number of lice suggesting trade-offs in reproductive investment possibly due to the costs associated with spermatogenesis and immunity. We suggest when measuring sexual differences in immunity it is important to consider the effects of reproductive pressures, parasite types, and life history costs

Should wider HIV testing be encouraged on the grounds of HIV prevention?

The issue of the role of HIV testing in HIV prevention is an important one. Some commentators have argued that HIV testing should be encouraged more widely on the grounds that it can stimulate behaviour change to safe sex and drug use. Testing has been advanced as an important means to control the epidemic. There is, however, insufficient evidence to support this contention at this time. The hypothesis of a link between HIV testing and behaviour change is based on the assumption of a linear relationship. It is argued that this assumption is based on two others, that the ‘stimulus’ of testing and counselling is uniform, and that the information will be perceived and used by all recipients in an identical way. It is argued that there is currently insufficient research evidence to encourage more widespread testing on prevention grounds. Issues which should be considered in future research designs are discussed

Gay men & HIV: community responses and personal risks

This paper reports on the results of qualitative studies examining the personal experiences of sex and sexual negotiation for British gay men who are diagnosed HIV positive and those who know or presume themselves to be uninfected. These are contrasted with the results of a study of representations of HIV and AIDS within an international review of community health promotion literature aimed at gay men. The paper highlights the disparity between specific community responses to the epidemic as engendered in the cultural production of health promotion materials and the individual experience of HIV, suggesting a paradigm for a community response to the epidemic which reflects the personal experience of gay men both infected and uninfected

Commissioning into genito urinary medicine Lessons from a review of 21 London clinics

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No aggregate change in homosexual HIV risk behaviour among gay men attending the gay pride festivals, UK, 1993-95

Objectives: To examine aggregate changes in homosexual HIV risk taking among gay men attending the Gay Pride festival in the United Kingdom over a three year period during which HIV prevention activity targeted at this population increased considerably. Design: Three cross-sectional self-completion questionnaires at yearly intervals asking identical questions on sexual behaviour in the preceding year. Setting: Lesbian and Gay Pride festival held in London, June 1993, 1994 and 1995. Participants: Men attending the festival who were UK resident, had ever had sex with another man and who were willing to fill out a questionnaire (N= 1620, 1753 and 1168 in 1993, 1994, and 1995, respectively). Main outcome measures: Self reported numbers of sexual partners, sexual partners with whom ano- penile intercourse occurred and sexual partners with whom ano-penile intercourse occurred without a condom. Results: Over the three year period there were no changes in the proportion of men engaging in any of the sexual behaviour measures. At each cross-section, one in three men (514 out of 1566, 511 out of 1612, 351 out of 1059) had engaged in AI without a condom with at least one male partner in the preceding year and one in ten (162 out of 1566, 156 out of 1612, 103 out of 1059) had done so with more than one male partner. Conclusion: Despite an increase in prevention work targeted at this population, aggregate levels of sexual risk taking have remained very stable. A reassessment of the efficacy of current HIV prevention messages and methods with this population is urgently required

HIV testing services in North Thames (East)

Review carried out by Sigma ResearchAvailable from British Library Document Supply Centre- DSC:OP-LG/8127 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo