10,006 research outputs found

    “For her own safety and the good of society at large”: Eugenics, Sterilization, and Anglo-American Transnationalism in Newfoundland, 1928-1934

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    From 1928 to 1934, about half of the two dozen women who were surgically sterilized while under the care of American doctors working with the International Grenfell Association (IGA) in St. Anthony, Newfoundland, were sterilized because they were deemed to be mentally unfit or substandard. These sterilizations coincided with rising concern about feebleminded persons and eugenic and legislative solutions across the United States, the British Empire, and beyond, but Newfoundland did not develop a eugenic movement nor did it enact laws to sanction surgical sterilization. What happened in St. Anthony was a result of the otherwise beneficial “Americanization” of the IGA.Environ la moitiĂ© des deux douzaines de femmes qui subirent une stĂ©rilisation chirurgicale entre 1928 et 1934 alors qu’elles Ă©taient soignĂ©es par des mĂ©decins amĂ©ricains qui travaillaient pour l’International Grenfell Association (IGA) Ă  St. Anthony (Terre-Neuve) furent stĂ©rilisĂ©es parce qu’elles Ă©taient considĂ©rĂ©es comme mentalement inaptes ou infĂ©rieures. Ces stĂ©rilisations coĂŻncidaient avec la montĂ©e des prĂ©occupations suscitĂ©es par les personnes d’esprit faible et des solutions eugĂ©niques et lĂ©gislatives adoptĂ©es aux États-Unis, dans l’empire britannique et au-delĂ . Aucun mouvement eugĂ©nique ne vit cependant le jour Ă  Terre-Neuve, qui n’adopta pas de lois pour approuver la stĂ©rilisation chirurgicale. Ce qui se produisit Ă  St. Anthony Ă©tait le rĂ©sultat de l’amĂ©ricanisation de l’IGA, qui fut par ailleurs bĂ©nĂ©fique

    Semiclassical ionization dynamics of the hydrogen molecular ion in an electric field of arbitrary orientation

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    Quasi-static models of barrier suppression have played a major role in our understanding of the ionization of atoms and molecules in strong laser fields. Despite their success, in the case of diatomic molecules these studies have so far been restricted to fields aligned with the molecular axis. In this paper we investigate the locations and heights of the potential barriers in the hydrogen molecular ion in an electric field of arbitrary orientation. We find that the barriers undergo bifurcations as the external field strength and direction are varied. This phenomenon represents an unexpected level of intricacy even on this most elementary level of the dynamics. We describe the dynamics of tunnelling ionization through the barriers semiclassically and use our results to shed new light on the success of a recent theory of molecular tunnelling ionization as well as earlier theories that restrict the electric field to be aligned with the molecular axis

    Semiclassical quantization of the hydrogen atom in crossed electric and magnetic fields

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    The S-matrix theory formulation of closed-orbit theory recently proposed by Granger and Greene is extended to atoms in crossed electric and magnetic fields. We then present a semiclassical quantization of the hydrogen atom in crossed fields, which succeeds in resolving individual lines in the spectrum, but is restricted to the strongest lines of each n-manifold. By means of a detailed semiclassical analysis of the quantum spectrum, we demonstrate that it is the abundance of bifurcations of closed orbits that precludes the resolution of finer details. They necessitate the inclusion of uniform semiclassical approximations into the quantization process. Uniform approximations for the generic types of closed-orbit bifurcation are derived, and a general method for including them in a high-resolution semiclassical quantization is devised

    Novel use of stir bar sorptive extraction (SBSE) as a tool for isolation of oviposition site attractants for gravid Culex quinquefasciatus

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    Mosquitoes such as Culex quinquefasciatus Say (Diptera: Culicidae) are important vectors of organisms that cause disease in humans. Research into the development of effective standardized odour baits for blood-fed females (oviposition attractants), to enable entomological monitoring of vector populations, is hampered by complex protocols for extraction of physiologically active volatile chemicals from natural breeding site water samples, which have produced inconsistent results. Air entrainment and solvent extraction are technically demanding methods and are impractical for use in resource poor environments where mosquito-borne disease is most prevalent. This study reports the first use of a simple, robust extraction technique, stir bar sorptive extraction (SBSE), to extract behaviourally active small lipophilic molecules (SLMs) present in water samples collected from Cx. quinquefasciatus breeding sites in Tanzania. Extracts from a pit latrine and from a cess pool breeding site attracted more gravid Cx. quinquefasciatus in pair choice bioassays than control extracts, and coupled gas chromatography-electroantennography (GC-EAG) allowed tentative identification of 15 electrophysiologically active chemicals, including the known oviposition attractant, skatole (3-methylindole). Here, we have demonstrated, using simple pair choice bioassays in controlled laboratory conditions, that SBSE is effective for the extraction of behaviourally and electrophysiologically active semiochemicals from mosquito breeding site waters. Further research is required to confirm that SBSE is an appropriate technique for use in field surveys in the search for oviposition cues for Cx. quinquefasciatus

    Clinical translation of positive metastases identified on prostate-specific membrane antigen positron emission tomography/computed tomography imaging in the management of de novo synchronous oligometastatic prostate cancer

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    Recent randomised evidence supports the diagnostic superiority of prostate-specific membrane antigen (PSMA) PET/CT, over conventional imaging, in the detection of distant occult metastasis in men with newly diagnosed high-risk prostate cancer. This may result in a rise in the detection of de novo synchronous hormone-sensitive “oligometastatic” prostate cancer. We outline the evidence supporting PSMA PET/CT imaging in primary staging. We also discuss the translation of positive areas, with a high probability of distant metastasis, into clinical therapeutic targets for metastasis-directed interventions. Finally, we highlight the role of PSMA PET/CT as an imaging biomarker. This may have future utility in disease monitoring and prediction of response to systemic, local cytoreductive and metastasis-directed interventions. Patient Summary: A new whole-body scan can accurately detect cancer deposits, in men in whom distant prostate cancer spread is suspected. This may be useful to monitor and predict response to drug therapy, treatments to the prostate and cancer deposits

    An Intervention Approach for Children with Teacher- and Parent-Identified Attentional Difficulties

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    Using a multimodal and multi-informant method for diagnosis, we selected 33 children by teacher and parent nomination for attention and work completion problems that met DSM-IV criteria for attention-deficit/hyperactivity disorder (ADHD). Of the 33 children in this group, 21 participated in the initial intervention, and 12 were placed in an ADHD control group and received the intervention after pre- and post-testing. A similarly selected group of 21 children without difficulties in attention and work completion served as a control group. Each child was assessed on pre- and posttest measures of visual and auditory attention. After an 18-week intervention period that included attention and problem-solving training, all children in the intervention and control groups were retested on visual and auditory tasks. Children in both ADHD groups showed significantly poorer initial performance on the visual attention task. Whereas the ADHD intervention group showed commensurate performance to the nondisabled control group after training, the ADHD control group did not show significant improvement over the same period. Auditory attention was poorer compared to the control group for both ADHD groups initially and improved only for the ADHD intervention group. These findings are discussed as a possible intervention for children with difficulties in strategy selection in a classroom setting

    Jost Function for Singular Potentials

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    An exact method for direct calculation of the Jost function and Jost solutions for a repulsive singular potential is presented. Within this method the Schrodinger equation is replaced by an equivalent system of linear first-order differential equations, which after complex rotation, can easily be solved numerically. The Jost function can be obtained to any desired accuracy for all complex momenta of physical interest, including the spectral points corresponding to bound and resonant states. The method can also be used in the complex angular-momentum plane to calculate the Regge trajectories. The effectiveness of the method is demonstrated using the Lennard-Jones (12,6) potential. The spectral properties of the realistic inter-atomic He4-He4 potentials HFDHE2 and HFD-B of Aziz and collaborators are also investigated.Comment: 12 pages, latex, 2 eps-figures, submitted to Phys.Rev.

    Photoabsorption spectra of the diamagnetic hydrogen atom in the transition regime to chaos: Closed orbit theory with bifurcating orbits

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    With increasing energy the diamagnetic hydrogen atom undergoes a transition from regular to chaotic classical dynamics, and the closed orbits pass through various cascades of bifurcations. Closed orbit theory allows for the semiclassical calculation of photoabsorption spectra of the diamagnetic hydrogen atom. However, at the bifurcations the closed orbit contributions diverge. The singularities can be removed with the help of uniform semiclassical approximations which are constructed over a wide energy range for different types of codimension one and two catastrophes. Using the uniform approximations and applying the high-resolution harmonic inversion method we calculate fully resolved semiclassical photoabsorption spectra, i.e., individual eigenenergies and transition matrix elements at laboratory magnetic field strengths, and compare them with the results of exact quantum calculations.Comment: 26 pages, 9 figures, submitted to J. Phys.

    An integrated dynamic modeling framework for investigating the impact of climate change and variability on irrigated agriculture

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    Many hydrologic systems are likely to be affected by climate change. This is of particular importance given that agricultural production systems are inextricably linked to the hydrologic systems they rely upon. Although irrigation is often employed as a method to dampen the effect of short-term variation in climatic inputs to agricultural production, sources of irrigation water are not immune to long-term climatic change. Irrigation water use decisions are most often made at the farm level. It is at this scale that the economic and social impacts of climate change will be manifest. This paper presents an integrated stochastic dynamic modeling framework that can be used to investigate the viability of irrigated farms under alternative climate change scenarios. The framework is applied to a theoretical farm in the Murray Darling Basin, Australia, under four potential future climate scenarios. It is found that neglecting interannual variability in climatic inputs to agriculture consistently underestimates the reduction in farm viability caused by climate change and that multiyear sequences of climate states strongly influence estimates of farm profitability.Timothy S. C. Rowan, Holger R. Maier, Jeff Connor and Graeme C. Dand
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