364 research outputs found

    Self consistent determination of plasmonic resonances in ternary nanocomposites

    Full text link
    We have developed a self consistent technique to predict the behavior of plasmon resonances in multi-component systems as a function of wavelength. This approach, based on the tight lower bounds of the Bergman-Milton formulation, is able to predict experimental optical data, including the positions, shifts and shapes of plasmonic peaks in ternary nanocomposites without using any ftting parameters. Our approach is based on viewing the mixing of 3 components as the mixing of 2 binary mixtures, each in the same host. We obtained excellent predictions of the experimental optical behavior for mixtures of Ag:Cu:SiO2 and alloys of Au-Cu:SiO2 and Ag-Au:H2 O, suggesting that the essential physics of plasmonic behavior is captured by this approach.Comment: 7 pages and 4 figure

    Learned helplessness in chess players: The importance of task similarity and the role of skill

    Get PDF
    The effects of noncontingency between subjects' responses and outcomes were examined with respect to treatment/posttest similarity and skill in the task. The experimental design consisted of three groups. The first group had to solve chess problems with objective solutions and received veridical feedback; each member of the second group faced problems with no objective solutions, and received the same feedback as the member of the first group he was yoked with, but without any control on it; the control group received a waiting task. It was found that the group with unsolvable problems was more depressed than the two other groups at the end of the experiment. The mid-strength players were the most sensitive to the manipulation, and the weakest players showed little effect of learned helplessness. It was also found that the effects were proportional to the degree of similarity between the treatment and the posttest. The results limit the domain of applicability of the learned helplessness model

    Diversity in collaborative research communities: a multicultural, multidisciplinary thesis writing group in public health

    Get PDF
    Writing groups for doctoral students are generally agreed to provide valuable learning spaces for Ph.D. candidates. Here an academic developer and the eight members of a writing group formed in a Discipline of Public Health provide an account of their experiences of collaborating in a multicultural, multidisciplinary thesis writing group. We consider the benefits of belonging to such a group for Ph.D. students who are operating in a research climate in which disciplinary boundaries are blurring and where an increasing number of doctoral projects are interdisciplinary in nature; in which both academic staff and students come from enormously diverse cultural and language backgrounds; and in which teamwork, networking and collaboration are prized but not always proactively facilitated. We argue that doctoral writing groups comprising students from diverse cultural and disciplinary backgrounds can be of significant value for postgraduates who wish to collaborate on their own academic development to improve their research writing and communication skills; at the same time, such collaborative work effectively builds an inclusive, dynamic research community.Cally Guerin, Vicki Xafis, Diana V. Doda, Marianne H. Gillam, Allison J. Larg, Helene Luckner, Nasreen Jahan, Aris Widayati and Chuangzhou X

    Older patients' attitudes towards and experiences of patient-physician end-of-life communication: a secondary analysis of interviews from British, Dutch and Belgian patients

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Older patients often experience sub-standard communication in the palliative phase of illness. Due to the importance of good communication in patient-centred end-of-life care, it is essential to understand the factors which influence older patients’ communication with physicians. This study examines older patients’ attitudes towards, and experiences of, patient-physician end-of-life (EoL) communication in three European countries.</p> <p>Methods</p> <p>A secondary analysis of interviews from British, Dutch and Belgian patients over the age of 60 with a progressive terminal illness was conducted. Cross-cutting themes were identified using a thematic approach.</p> <p>Results</p> <p>Themes from 30 interviews (Male n = 20, Median age 78.5) included: confidence and trust; disclosure and awareness; and participation in decision-making. Confidence and trust were reinforced by physicians’ availability, time and genuine attention and hindered by misdiagnoses and poor communication style. Most participants preferred full disclosure, though some remained deliberately ill-informed to avoid distress. Patients expressed a variety of preferences for and experiences of involvement in medical EoL decision-making and a few complained that information was only provided about the physician's preferred treatment.</p> <p>Conclusions</p> <p>A variety of experiences and attitudes regarding disclosure and participation in decision-making were reported from each country, suggesting that communication preferences are highly individual. It is important that physicians are sensitive to this diversity and avoid stereotyping. In regard to communication style, physicians are advised to provide clear explanations, avoid jargon, and continually check understanding. Both the ‘informed’ and the ‘shared’ patient-physician decision-making models assume patients make rational choices based on a clear understanding of treatment options. This idealized situation was often not reflected in patients’ experiences.</p

    Harmful algal blooms and eutrophication : examining linkages from selected coastal regions of the United States

    Get PDF
    Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Harmful Algae 8 (2008): 39-53, doi:10.1016/j.hal.2008.08.017.Coastal waters of the United States (U.S.) are subject to many of the major harmful algal bloom (HAB) poisoning syndromes and impacts. These include paralytic shellfish poisoning (PSP), neurotoxic shellfish poisoning (NSP), amnesic shellfish poisoning (ASP), ciguatera fish poisoning (CFP) and various other HAB phenomena such as fish kills, loss of submerged vegetation, shellfish mortalities, and widespread marine mammal mortalities. Here, the occurrences of selected HABs in a selected set of regions are described in terms of their relationship to eutrophication, illustrating a range of responses. Evidence suggestive of changes in the frequency, extent or magnitude of HABs in these areas is explored in the context of the nutrient sources underlying those blooms, both natural and anthropogenic. In some regions of the U.S., the linkages between HABs and eutrophication are clear and well documented, whereas in others, information is limited, thereby highlighting important areas for further research.Support was provided through the Woods Hole Center for Oceans and Human Health (to DMA), National Science Foundation (NSF) grants OCE-9808173 and OCE-0430724 (to DMA), OCE-0234587 (to WPC), OCE04-32479 (to MLP), OCE-0138544 (to RMK), OCE-9981617 (to PMG); National Institute of Environmental Health Sciences (NIEHS) grants P50ES012742-01 (to DMA) and P50ES012740 (to MLP); NOAA Grants NA96OP0099 (to DMA), NA16OP1450 (to VLT), NA96P00084 (to GAV and CAH), NA160C2936 and NA108H-C (to RMK), NA860P0493 and NA04NOS4780241 (to PMG), NA04NOS4780239-02 (to RMK), NA06NOS4780245 (to DWT). Support was also provided from the West Coast Center for Oceans and Human Health (to VLT and WPC), USEPA Grant CR826792-01-0 (to GAV and CAH), and the State of Florida Grant S7701617826 (to GAV and CAH)
    • …
    corecore