702 research outputs found

    Bio-R/evolution in historiographic perspective: some reflections on the history and epistemology of biomolecular science

    Get PDF
    Does the molecular vision of life signify a unique revolution in biology or a more general evolution of the life sciences in the twentieth century? This paper visits this ‘big question’ by reflecting on a series of major debates in the historiography of molecular biology, especially those regarding its origins and the periodization of its development. For instance, while some have suggested that the discipline emerged in the 1930s, others have argued for its birth in the post-WWII era. Above all, the impact of the Rockefeller Foundation and the physical sciences on the formation of molecular biology remains a central topic of discussion among historians of biology. Unlike earlier historians of biomolecular science, recent scholars have also started to pay closer attention to the laboratory and material cultures that had conditioned its historical shaping. This paper argues that, ultimately, these debates all rest upon one fundamental historiographical problem: the absence of a unifying understanding of ‘molecular biology’ among historians (and practitioners) of biological science. This heterogeneous conceptualization of ‘molecular biology’, however, should be viewed as valuable because it allows for multiple approaches to resolving the ‘revolution versus evolution’ debate that together enrich our interpretation of the twentieth-century biomolecular vision of life

    Urothelial Inverted Papilloma of the Lower Urinary Tract—A Benign Lesion or a Precursor of Malignancy?

    Get PDF
    ObjectiveWe investigated the clinical characteristics and follow-up results of patients with a lower urinary tract inverted papilloma (IP) in our hospital, with the intention of clarifying whether certain groups require more aggressive surveillance.Materials and MethodsWe conducted a retrospective study of lower urinary tract IP, using the pathology database of Taipei Veterans General Hospital, from September 1992 to February 2008. In total, 67 patients were enrolled. Patients' clinical characteristics, symptoms, tumor locations, and follow-up data were analyzed.ResultsAmong the 67 patients diagnosed with IP, 59 were male and eight were female, with a mean age of 67.9 ± 12.4 years. Gross hematuria and lower-urinary-tract symptoms were the most common symptoms. All of the patients received transurethral resection as initial treatment. Thirty-eight of these patients were monitored for a median of 21 months (range: 3–168 months). Seven patients had synchronous urothelial malignancies, and one had recurrent IP during follow-up. No patient had subsequent urothelial carcinoma or IP recurrence without a synchronous or previous urothelial malignancy during follow-up.ConclusionThere is a low incidence of developing a subsequent malignancy with a simple IP lesion during follow-up. Rigorous surveillance may be unnecessary in IP patients without a synchronous or previous urothelial malignancy

    Work stress and cancer researchers : an exploration of the challenges, experiences and training needs of UK cancer researchers.

    Get PDF
    Work stress is a significant issue for many UK healthcare professionals, in particular those working in the field of oncology. However, there have been very few attempts to explore the challenges, experiences or training needs of researchers working in cancer research. In doing so, we will be better positioned to support and develop these researchers. 18 UK oncology researchers from a variety of backgrounds took part in a semi-structured interview. Interviews were transcribed and analysed using thematic analysis. The analysis identified two overarching themes: logistical research issues (workload, accessing/ recruiting participants, finances) and sensitive research issues (emotional demands, professional boundaries, sensitivity around recruitment). One cross-cutting theme, supportive strategies (support and training, coping mechanisms), was seen to influence both logistical and sensitive research issues. While further research is needed to fully understand the causes and impact of work stress on cancer researchers, three specific issues were highlighted: emotional demands are relevant to quantitative and mixed methods researchers as well as those engaged in qualitative research; the researchers’ background (experience; clinical/non-clinical) was influential and an exploration of effective coping strategies is required; and there is a clear need for adequate support systems and training to be available, particularly for early career researchers.</p

    Evolutionary Tracks of Trapped, Accreting Protoplanets: the Origin of the Observed Mass-Period Relation

    Full text link
    The large number of observed exoplanets (≳\gtrsim 700) provides important constraints on their origin as deduced from the mass-period diagram of planets. The most surprising features in the diagram are 1) the (apparent) pile up of gas giants at a period of ∌500\sim 500 days (∌1\sim1 AU) and 2) the so-called mass-period relation which indicates that planetary mass is an increasing function of orbital period. We construct the evolutionary tracks of growing planets at planet traps in evolving protoplanetary disks and show that they provide a good physical understanding of how these observational properties arise. The fundamental feature of our model is that inhomogeneities in protoplanetary disks give rise to multiple (up to 3) trapping sites for rapid (type I) planetary migration of planetary cores. The viscous evolution of disks results in the slow radial movement of the traps and their cores from large to small orbital periods. In our model, the slow inward motion of planet traps is coupled with the standard core accretion scenario for planetary growth. As planets grow, type II migration takes over. Planet growth and radial movement are ultimately stalled by the dispersal of gas disks via photoevaporation. Our model makes a number of important predictions: that distinct sub-populations of planets that reflect the properties of planet traps where they have grown result in the mass-period relation; that the presence of these sub-populations naturally explains a pile-up of planets at ∌1\sim 1 AU; and that evolutionary tracks from the ice line do put planets at short periods and fill an earlier claimed "planet desert" - sparse population of planets in the mass-semi-major axis diagram.Comment: 20 pages, 11 figures, 9 tables; accepted for publication in ApJ. No change in our conclusions while more discussion is added for supporting the importance of planet trap

    Introduction: transnational lesbian cultures

    Get PDF
    This Introduction sets out the aims and scope of this special journal issue. The issue examines the transnational shape and shaping of lesbian lives and cultures in and across China, India, the United Kingdom, and the United States. It uses the expression “transnational lesbian cultures” to suggest that despite sometimes radically different sociopolitical and cultural contexts, the lived experiences of same-sex desire and their emotional attachments create particular affinities between women who love women, affinities that reach across the distinct cultural and social contexts that shape them. The articles brought together explore lesbian subcultures, film, graphic novels, music, and online intimacies. They show that as a cultural and political signifier and as an analytical tool, lesbian troubles and complicates contemporary sexual politics, not least by revealing some of the gendered structures that shape debates about sexuality in a range of critical, cultural and political contexts. While the individual pieces cover a wide range of issues and concerns—which are often highly specific to the historical, cultural, and political contexts they discuss—together they tell a story about contemporary transnational lesbian culture: one that is marked by intricate links between norms and their effects and shaped by the efforts to resist denial, discrimination, and sometimes even active persecution

    Observation of a Smoothly Tunable Dirac Point in Ge(BixSb1−x)2Te4Ge(Bi_{x}Sb_{1-x})_{2}Te_{4}

    Full text link
    State-of-the-art topological devices require the use topological surface states to drive electronic transport. In this study, we examine a tunable topological system, Ge(BixSb1−x)2Te4Ge(Bi_{x}Sb_{1-x})_{2}Te_{4}, for a range of 'x' values from 0 to 1, using a combination of Fourier Transform Scanning Tunneling Spectroscopy (FT-STS) and Angle-Resolved Photoemission Spectroscopy (ARPES). Our results show that the Dirac point shifts linearly with 'x', crossing the Fermi energy near x = 0.7. This novel observation of a smoothly tunable, isolated Dirac point crossing through the topological transport regime and having strong linear dependence with substitution can be critical for future topological spintronics applications.Comment: 18 Pages, 9 Figures, including Appendi
    • 

    corecore