5,501 research outputs found

    Roscoe Reid Graham (1890 to 1948): a Canadian pioneer in general surgery.

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    Roscoe Reid Graham, a Canadian surgeon trained at the University of Toronto, was a true pioneer in the field of general surgery. Although he may be best known for his omental patch repair of perforated duodenal ulcers-often referred to as the Graham patch -he had a number of other significant accomplishments that decorated his surgical career. Dr. Graham is credited with being the first surgeon to successfully enucleate an insulinoma. He ventured to do an essentially brand new operation based solely on his patient\u27s symptoms and physical findings, a courageous move that even some of the most talented surgeons would shy away from. He also spent a large portion of his career dedicated to the study of rectal prolapse, working tirelessly to rid his patients of this awful affliction. He was recognized by a number of different surgical associations for his operative successes and was awarded membership to those both in Canada and the United States. Despite all of these accolades, Dr. Graham remained grounded and always fervent in his dedication to the patient and their presenting symptom(s), reminding us that to do anything more would be meddlesome. In an age when medical professionals are often all too eager to make unnecessary interventions, it is imperative that we look back at our predecessors such as Roscoe Reid Graham, for they will continually redirect us toward our one and only obligation: the patient

    Mary H. Gibbon: teamwork of the heart.

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    Mary Maly Hopkinson Gibbon was born on September 25, 1903, to an affluent New England family who encouraged her to embrace her intelligence and to follow that by which she was intrigued. In doing this, Maly pursued work in scientific research, where she ultimately met her first husband, Dr. John ‘‘Jack’’ H. Gibbon. Jack and Maly were partners in every sense of the word. Their collaboration, both within and beyond the walls of the research laboratory, made it possible for the Gibbon dream of the heart–lung machine to be realized

    Discrimination against Mixed-Status Families and its Health Impact on Latino Children

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    Background and Objective: Restrictive immigration policies and discrimination are associated with negative health outcomes for immigrant and Latino families. Mixed-status families represent a unique subpopulation of Latinos affected by restrictive immigration policies. This qualitative study explored discrimination against mixed-status families and its potential health impact on Latino children from the perspective of Latina mothers. Methods: In 2017, twenty in-depth interviews with Latina mothers of mixed-status families living in northwestern North Carolina were conducted, transcribed, and analyzed. Constant comparison, an approach to grounded theory development, was used. Results: Nine themes emerged that reflected experiences with discrimination and its negative impact on children. Themes included more frequent and severe discrimination during and after the 2016 US presidential election, determination to stay together and remain in the US, experiences of discrimination in multiple settings, the impact of discrimination on child health and well-being, the impact of fear and stress on meeting the needs of children, the burden on children serving as liaisons between families and services, the inability of citizenship to protect against the effects of discrimination, positive and hopeful responses to discrimination, and the potential role of education in building a foundation for reducing discrimination (and thus promoting the health and well-being of Latino children) in the future. Conclusions: Discrimination against mixed-status Latino families constitutes a critical threat to the health and well-being of Latino children. Further research should inform immigration policies that support (rather than threaten) the health, well-being, and health care practices that mitigate the stresses experienced by Latino children

    Reducing vortex density in superconductors using the ratchet effect

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    A serious obstacle that impedes the application of low and high temperature superconductor (SC) devices is the presence of trapped flux. Flux lines or vortices are induced by fields as small as the Earth's magnetic field. Once present, vortices dissipate energy and generate internal noise, limiting the operation of numerous superconducting devices. Methods used to overcome this difficulty include the pinning of vortices by the incorporation of impurities and defects, the construction of flux dams, slots and holes and magnetic shields which block the penetration of new flux lines in the bulk of the SC or reduce the magnetic field in the immediate vicinity of the superconducting device. Naturally, the most desirable would be to remove the vortices from the bulk of the SC. There is no known phenomenon, however, that could form the basis for such a process. Here we show that the application of an ac current to a SC that is patterned with an asymmetric pinning potential can induce vortex motion whose direction is determined only by the asymmetry of the pattern. The mechanism responsible for this phenomenon is the so called ratchet effect, and its working principle applies to both low and high temperature SCs. As a first step here we demonstrate that with an appropriate choice of the pinning potential the ratchet effect can be used to remove vortices from low temperature SCs in the parameter range required for various applications.Comment: 7 pages, 4 figures, Nature (in press

    On the Theory of Evolution Versus the Concept of Evolution: Three Observations

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    Here we address three misconceptions stated by Rice et al. in their observations of our article Paz-y-Miño and Espinosa (Evo Edu Outreach 2:655–675, 2009), published in this journal. The five authors titled their note “The Theory of Evolution is Not an Explanation for the Origin of Life.” First, we argue that it is fallacious to believe that because the formulation of the theory of evolution, as conceived in the 1800s, did not include an explanation for the origin of life, nor of the universe, the concept of evolution would not allow us to hypothesize the possible beginnings of life and its connections to the cosmos. Not only Stanley Miller’s experiments of 1953 led scientists to envision a continuum from the inorganic world to the origin and diversification of life, but also Darwin’s own writings of 1871. Second, to dismiss the notion of Rice et al. that evolution does not provide explanations concerning the universe or the cosmos, we identify compelling scientific discussions on the topics: Zaikowski et al. (Evo Edu Outreach 1:65–73, 2008), Krauss (Evo Edu Outreach 3:193–197, 2010), Peretó et al. (Orig Life Evol Biosph 39:395–406, 2009) and Follmann and Brownson (Naturwissenschaften 96:1265–1292, 2009). Third, although we acknowledge that the term Darwinism may not be inclusive of all new discoveries in evolution, and also that creationists and Intelligent Designers hijack the term to portray evolution as ideology, we demonstrate that there is no statistical evidence suggesting that the word Darwinism interferes with public acceptance of evolution, nor does the inclusion of the origin of life or the universe within the concept of evolution. We examine the epistemological and empirical distinction between the theory of evolution and the concept of evolution and conclude that, although the distinction is important, it should not compromise scientific logic

    Menstrual cycle phase does not predict political conservatism

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    Recent authors have reported a relationship between women's fertility status, as indexed by menstrual cycle phase, and conservatism in moral, social and political values. We conducted a survey to test for the existence of a relationship between menstrual cycle day and conservatism. 2213 women reporting regular menstrual cycles provided data about their political views. Of these women, 2208 provided information about their cycle date, 1260 provided additional evidence of reliability in self-reported cycle date, and of these, 750 also indicated an absence of hormonal disruptors such as recent hormonal contraception use, breastfeeding or pregnancy. Cycle day was used to estimate day-specific fertility rate (probability of conception); political conservatism was measured via direct self-report and via responses to the "Moral Foundations” questionnaire. We also recorded relationship status, which has been reported to interact with menstrual cycle phase in determining political preferences. We found no evidence of a relationship between estimated cyclical fertility changes and conservatism, and no evidence of an interaction between relationship status and cyclical fertility in determining political attitudes. Our findings were robust to multiple inclusion/exclusion criteria and to different methods of estimating fertility and measuring conservatism. In summary, the relationship between cycle-linked reproductive parameters and conservatism may be weaker or less reliable than previously thought

    A citizen science based survey method for estimating the density of urban carnivores

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    Globally there are many examples of synanthropic carnivores exploiting growth in urbanisation. As carnivores can come into conflict with humans and are potential vectors of zoonotic disease, assessing densities in suburban areas and identifying factors that influence them are necessary to aid management and mitigation. However, fragmented, privately owned land restricts the use of conventional carnivore surveying techniques in these areas, requiring development of novel methods. We present a method that combines questionnaire distribution to residents with field surveys and GIS, to determine relative density of two urban carnivores in England, Great Britain. We determined the density of: red fox (Vulpes vulpes) social groups in 14, approximately 1km2 suburban areas in 8 different towns and cities; and Eurasian badger (Meles meles) social groups in three suburban areas of one city. Average relative fox group density (FGD) was 3.72 km-2, which was double the estimates for cities with resident foxes in the 1980’s. Density was comparable to an alternative estimate derived from trapping and GPS-tracking, indicating the validity of the method. However, FGD did not correlate with a national dataset based on fox sightings, indicating unreliability of the national data to determine actual densities or to extrapolate a national population estimate. Using species-specific clustering units that reflect social organisation, the method was additionally applied to suburban badgers to derive relative badger group density (BGD) for one city (Brighton, 2.41 km-2). We demonstrate that citizen science approaches can effectively obtain data to assess suburban carnivore density, however publicly derived national data sets need to be locally validated before extrapolations can be undertaken. The method we present for assessing densities of foxes and badgers in British towns and cities is also adaptable to other urban carnivores elsewhere. However this transferability is contingent on species traits meeting particular criteria, and on resident responsiveness

    Larval ecology of mosquitoes in sylvatic arbovirus foci in southeastern Senegal

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    BACKGROUND: Although adult mosquito vectors of sylvatic arbovirus [yellow fever (YFV), dengue-2 (DENV-2) and chikungunya (CHIKV)] have been studied for the past 40 years in southeastern Senegal, data are still lacking on the ecology of larval mosquitoes in this area. In this study, we investigated the larval habitats of mosquitoes and characterized their seasonal and spatial dynamics in arbovirus foci. METHODS: We searched for wet microhabitats, classified in 9 categories, in five land cover classes (agriculture, forest, savannah, barren and village) from June, 2010 to January, 2011. Mosquito immatures were sampled monthly in up to 30 microhabitats of each category per land cover and bred until adult stage for determination. RESULTS: No wet microhabitats were found in the agricultural sites; in the remaining land covers immature stages of 35 mosquito species in 7 genera were sampled from 9 microhabitats (tree holes, fresh fruit husks, decaying fruit husks, puddles, bamboo holes, discarded containers, tires, rock holes and storage containers). The most abundant species was Aedes aegypti formosus, representing 30.2% of the collections, followed by 12 species, representing each more than 1% of the total, among them the arbovirus vectors Ae. vittatus (7.9%), Ae. luteocephalus (5.7%), Ae. taylori (5.0%), and Ae. furcifer (1.3%). Aedes aegypti, Cx. nebulosus, Cx. perfuscus, Cx. tritaeniorhynchus, Er. chrysogster and Ae. vittatus were the only common species collected from all land covers. Aedes furcifer and Ae. taylori were collected in fresh fruit husks and tree holes. Species richness and dominance varied significantly in land covers and microhabitats. Positive associations were found mainly between Ae. furcifer, Ae. taylori and Ae. luteocephalus. A high proportion of potential enzootic vectors that are not anthropophilic were found in the larval mosquito fauna. CONCLUSIONS: In southeastern Senegal, Ae. furcifer and Ae. taylori larvae showed a more limited distribution among both land cover and microhabitat types than the other common species. Uniquely among vector species, Ae. aegypti formosus larvae occurred at the highest frequency in villages. Finally, a high proportion of the potential non-anthropophilic vectors were represented in the larval mosquito fauna, suggesting the existence of unidentified sylvatic arbovirus cycles in southeastern Senegal
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