3,841 research outputs found

    Nineteenth-Century Popular Science Magazines, Narrative, and the Problem of Historical Materiality

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    In his Some Reminiscences of a Lecturer, Andrew Wilson emphasizes the importance of narrative to popular science lecturing. Although Wilson promotes the teaching of science as useful knowledge in its own right, he also recognizes that the way science is taught can encourage audiences to take the subject up and read further on their own. Form, according to Wilson, should not be divorced from scientific content and lecturers should ensure that not only is their science accurate, but that it is presented in a way that will provoke curiosity and stimulate interest. This paper discusses the influence of narrative in structuring scientific objects and phenomena, and considers the consequences of such presentations for historical research. As scientific journalism necessarily weaves both its intended audience and the objects under discussion into its accounts, these texts demand that we recognize their nature as social relationships inscribed in historical objects

    Detection of European Strain of \u3ci\u3eEchinococcus multilocularis\u3c/i\u3e in North America

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    To the Editor: In 2009, an alveolar hydatid cyst, the intermediate stage of the cestode Echinococcus multilocularis, was detected in the liver of a dog from Quesnel, British Columbia (BC), Canada, 600 km west of the nearest known record of this parasite in central North America. Alveolar hydatid cysts normally occur in rodent intermediate hosts. However, humans can serve as aberrant intermediate hosts; cysts generally originate in the liver and, in about one third of cases, metastasize throughout the body. Detection of the larval stage of this pathogen in an unusual host in a new geographic region required application of multiple molecular epidemiologic techniques to determine if this was range expansion of a native strain or introduction of a new strain of veterinary and public health concern. The possible establishment of a European strain in North American wildlife, with spillover into domestic dogs, may have implications for public health and require increased vigilance by medical and veterinary personnel in the newly endemic region. Compared with native North American strains, European strains of E. multilocularis appear to have greater potential to cause alveolar hydatid disease (AHD) in humans. These strains are emerging worldwide (increasing in both prevalence and distribution) as a result of changes in landscape, climate, and wildlife–human interfaces. In Europe, human AHD can be fatal (definite or probable cause of death in 23.5% of 119 recent cases) and has low cure rates (5% of 408 recent cases). As of 2000, in Europe and Asia, the estimated cost per case of AHD was US 100,000–100,000–300,000. Therefore, better understanding of the distribution, genetic diversity, and pathogenicity of strains of E. multilocularis is needed to assess risks and mitigate costs for public and veterinary health, as well as to provide evidence for the regulation and screening of imported domestic animals and translocated wildlife

    Comparing Chemistry to Outcome: The Development of a Chemical Distance Metric, Coupled with Clustering and Hierarchal Visualization Applied to Macromolecular Crystallography

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    Many bioscience fields employ high-throughput methods to screen multiple biochemical conditions. The analysis of these becomes tedious without a degree of automation. Crystallization, a rate limiting step in biological X-ray crystallography, is one of these fields. Screening of multiple potential crystallization conditions (cocktails) is the most effective method of probing a proteins phase diagram and guiding crystallization but the interpretation of results can be time-consuming. To aid this empirical approach a cocktail distance coefficient was developed to quantitatively compare macromolecule crystallization conditions and outcome. These coefficients were evaluated against an existing similarity metric developed for crystallization, the C6 metric, using both virtual crystallization screens and by comparison of two related 1,536-cocktail high-throughput crystallization screens. Hierarchical clustering was employed to visualize one of these screens and the crystallization results from an exopolyphosphatase-related protein from Bacteroides fragilis, (BfR192) overlaid on this clustering. This demonstrated a strong correlation between certain chemically related clusters and crystal lead conditions. While this analysis was not used to guide the initial crystallization optimization, it led to the re-evaluation of unexplained peaks in the electron density map of the protein and to the insertion and correct placement of sodium, potassium and phosphate atoms in the structure. With these in place, the resulting structure of the putative active site demonstrated features consistent with active sites of other phosphatases which are involved in binding the phosphoryl moieties of nucleotide triphosphates. The new distance coefficient, CDcoeff, appears to be robust in this application, and coupled with hierarchical clustering and the overlay of crystallization outcome, reveals information of biological relevance. While tested with a single example the potential applications related to crystallography appear promising and the distance coefficient, clustering, and hierarchal visualization of results undoubtedly have applications in wider fields

    Type IIb Supernova SN 2011dh: Spectra and Photometry from the Ultraviolet to the Near-Infrared

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    We report spectroscopic and photometric observations of the Type IIb SN 2011dh obtained between 4 and 34 days after the estimated date of explosion (May 31.5 UT). The data cover a wide wavelength range from 2,000 Angstroms in the UV to 2.4 microns in the NIR. Optical spectra provide line profiles and velocity measurements of HI, HeI, CaII and FeII that trace the composition and kinematics of the SN. NIR spectra show that helium is present in the atmosphere as early as 11 days after the explosion. A UV spectrum obtained with the STIS reveals that the UV flux for SN 2011dh is low compared to other SN IIb. The HI and HeI velocities in SN 2011dh are separated by about 4,000 km/s at all phases. We estimate that the H-shell of SN 2011dh is about 8 times less massive than the shell of SN 1993J and about 3 times more massive than the shell of SN 2008ax. Light curves (LC) for twelve passbands are presented. The maximum bolometric luminosity of 1.8±0.2×10421.8 \pm 0.2 \times 10^{42} erg s−1^{-1} occurred about 22 days after the explosion. NIR emission provides more than 30% of the total bolometric flux at the beginning of our observations and increases to nearly 50% of the total by day 34. The UV produces 16% of the total flux on day 4, 5% on day 9 and 1% on day 34. We compare the bolometric light curves of SN 2011dh, SN 2008ax and SN 1993J. The LC are very different for the first twelve days after the explosions but all three SN IIb display similar peak luminosities, times of peak, decline rates and colors after maximum. This suggests that the progenitors of these SN IIb may have had similar compositions and masses but they exploded inside hydrogen shells that that have a wide range of masses. The detailed observations presented here will help evaluate theoretical models for this supernova and lead to a better understanding of SN IIb.Comment: 23 pages, 14 figures, 9 tables, accepted by Ap

    Pelvic Trauma: Wses Classification And Guidelines

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    Complex pelvic injuries are among the most dangerous and deadly trauma related lesions. Different classification systems exist, some are based on the mechanism of injury, some on anatomic patterns and some are focusing on the resulting instability requiring operative fixation. The optimal treatment strategy, however, should keep into consideration the hemodynamic status, the anatomic impairment of pelvic ring function and the associated injuries. The management of pelvic trauma patients aims definitively to restore the homeostasis and the normal physiopathology associated to the mechanical stability of the pelvic ring. Thus the management of pelvic trauma must be multidisciplinary and should be ultimately based on the physiology of the patient and the anatomy of the injury. This paper presents the World Society of Emergency Surgery (WSES) classification of pelvic trauma and the management Guidelines.1

    Eisenstein Series of Weight One, q-Averages of the 0-Logarithm and Periods of Elliptic Curves

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    For any elliptic curve E over k ⊂ R with E(C) = C^×/q^Z, q = e^(2πiz),Im(z) >, we study the q-average D_(0,q), defined on E(C), of the function D_0(z) = Im(z/(1−z)). Let Ω+(E) denote the real period of E. We show that there is a rational function R ∈ Q(X_1(N)) such that for any non-cuspidal real point s ∈ X_1(N) (which defines an elliptic curve E(s) over R together with a point P(s) of order N), πD_(0,q)(P(s)) equals Ω+(E(s))R(s). In particular, if s is Q-rational point of X_1(N), a rare occurrence according to Mazur, R(s) is a rational number
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