Interfacial fracture energy and the toughness of composites

The premises upon which prevailing composite toughness theories are based are discussed in the light of observed strength variations in boron-epoxy composites with differing shear strengths of the interfacial bond. None of the extant toughness theories (pull-out, debonding, stress redistribution) successfully predicts the work of fracture of the boronepoxy system. However, incorporation of the work to create new surfaces into the total toughness analysis gives better agreement with experiment, and work of fracture predictions for other sytems, such as carbon-polyester, can also be modified. The approach is more generalized than the Outwater/Murphy debonding explanation for toughness, which in the way usually presented only applies when the filament fracture strain is greater than the matrix fracture strain. The present analysis suggests how to tailor the interfacial shear strength in order to obtain a reasonable toughness yet still maintain strengths of the order of the rule of mixtures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44787/1/10853_2004_Article_BF00737846.pd

Religious Tastes and Styles as Markers of Class Belonging: A Bourdieuian Perspective on Pentecostalism in South America

Studies on the relationship between social class and religion tend to highlight the demographic dimension of class, but neglect its symbolic dimension. By addressing the symbolic dimensions through a Bourdieuian approach, this article contends that religious tastes and styles can be employed as class markers within the sphere of religion. A case study on Argentinean Pentecostalism and in-depth analysis of a lower and middle class church illustrate how symbolic class differences are cultivated in the form of distinctive religious styles. While the lower class church displays a style marked by emotional expressiveness and the search for life improvement through spiritual practices, the middle class church performs a sober and calm style of Pentecostalism. The study highlights the role of styles in the reproduction of class boundaries, while shedding a critical light on the importance of tastes

Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

<div><p>The lucrative and highly migratory Atlantic bluefin tuna, <em>Thunnus thynnus</em> (Linnaeus 1758<em>;</em> Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity, but its biogeographic range has contracted since the 1950s. Most recently, the species disappeared from the Black Sea in the late 1980s and has not yet recovered. Reasons for the Black Sea disappearance, and the species-wide range contraction, are unclear. However bluefin tuna formerly foraged and possibly spawned in the Black Sea. Loss of a locally-reproducing population would represent a decline in population richness, and an increase in species vulnerability to perturbations such as exploitation and environmental change. Here we identify the main genetic and phenotypic adaptations that the population must have (had) in order to reproduce successfully in the specific hydrographic (estuarine) conditions of the Black Sea. By comparing hydrographic conditions in spawning areas of the three species of bluefin tunas, and applying a mechanistic model of egg buoyancy and sinking rate, we show that reproduction in the Black Sea must have required specific adaptations of egg buoyancy, fertilisation and development for reproductive success. Such adaptations by local populations of marine fish species spawning in estuarine areas are common as is evident from a meta-analysis of egg buoyancy data from 16 species of fish. We conclude that these adaptations would have been necessary for successful local reproduction by bluefin tuna in the Black Sea, and that a locally-adapted reproducing population may have disappeared. Recovery of bluefin tuna in the Black Sea, either for spawning or foraging, will occur fastest if any remaining locally adapted individuals are allowed to survive, and by conservation and recovery of depleted Mediterranean populations which could through time re-establish local Black Sea spawning and foraging.</p> </div

Decisional conflict in breast cancer patients considering immediate breast reconstruction

Background: Breast cancer (BC) patients who are treated with mastectomy are frequently offered immediate breast reconstruction. This study aimed to assess decisional conflict in patients considering immediate breast reconstruction, and to identify factors associated with clinically significant decisional conflict (CSDC). Methods: Baseline data of a multicenter randomized controlled trial evaluating the impact of an online decision aid for BC patients considering immediate breast reconstruction after mastectomy were analyzed. Participants completed questionnaires assessing sociodemographic and clinical characteristics, decisional conflict and other patient-reported outcomes related to decision-making such as breast reconstruction preference, knowledge, information resources used, preferred involvement in decision-making, information coping style, and anxiety. Multivariable logistic regression analysis was performed to identify factors associated with CSDC (score > 37.5 on decisional conflict). Results: Of the 250 participants, 68% experienced CSDC. Patients with a slight preference for breast reconstruction (odds ratio (OR) = 6.19, p < .01), with no preference for or against breast reconstruction (OR = 11.84, p < .01), and with a strong preference for no breast reconstruction (OR = 5.20, p < .05) were more likely to experience CSDC than patients with a strong preference for breast reconstruction. Furthermore, patients with more anxiety were more likely to experience CSDC (OR = 1.03, p = .01). Conclusion: A majority of BC patients who consider immediate breast reconstruction after mastectomy experience clinically significant decisional conflict. The findings emphasize the need for decision support, especially for patients who do not have a strong preference for breast reconstruction

Efficacy of a decision aid in breast cancer patients considering immediate reconstruction: results of a randomized controlled trial

PURPOSE: Breast cancer patients face complex decisions about immediate breast reconstruction (BR) after mastectomy. We evaluated the efficacy of an online decision aid in improving the decision-making process, decision quality and health outcomes in breast cancer patients considering immediate BR. METHODS: In a multicenter randomized controlled trial, patients were allocated to either the intervention group receiving care-as-usual (CAU) with access to an online decision aid, or the control group receiving CAU with an information leaflet. The primary outcome was decisional conflict. Secondary outcomes assessed the process of decision making (e.g. preparation for decision making, satisfaction with information), decision quality (decision regret, knowledge) and health outcomes (e.g. satisfaction with BR outcomes, body image). Patients completed questionnaires at baseline (T0), 1 week after consultation with a plastic surgeon (T1), 3 months (T2), and 12 months post-surgery (T3). RESULTS: We included 250 patients. Decisional conflict decreased over time in both groups, with no between group differences. Intervention participants felt better prepared for decision making than controls (P = .002). At T2, 87% of intervention participants were (very) satisfied with the information about BR, compared to 73% of control participants (P = .011). No significant between group differences were observed in any other outcome. CONCLUSION: Our online decision aid was as effective in reducing decisional conflict as an information leaflet about immediate BR after mastectomy. However, the decision aid substantially improved the decision-making process by better preparing breast cancer patients for decisions about immediate BR

A Fast Panel Code for Complex Actuator Disk Flows

A fast, linear scaling vortex method is presented to study inviscid incompressible flow problems involving one or more actuator disks. Building upon previous efforts that were limited to axi-symmetric flow cases, the proposed methodology is able to handle arbitrary configurations with no symmetry constraints. Applications include the conceptual study of wake interaction mechanisms in wind farms, and the correction of wind tunnel blockage effects in test sections of arbitrary shape. Actuator disks represent wind turbines through the shedding of a deformable vortex wake, discretized with a plaid of triangular distributed dipole singularities. An iterative method is adopted to align the wake with the local flow field, which is reconstructed from the vorticity field with a Green function approach. Interactions are computed with a Fast Multipole Method (FMM), effectively overcoming the quadratic scaling of computational time associated with traditional panel methods. When compared to direct computation, the use of an FMM algorithm reduced solution time by a factor 30 when studying the wake of a single actuator disk with 60000 panels. In the same case, the mass flux of the actuator streamtube was conserved to 0:002%. Finally, the presence of round and square impermeable walls around the actuator is considered to demonstrate the code applicability to wind tunnel wall interference correction problems