1,728 research outputs found

    “What’ s wrong with that woman?” – Positioning Theory and Information-Seeking Behaviour

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    Abstract We offer social positioning theory (Davies and Harre 1990) as a framework for exploring the ways in which the visibility of an individual’ s health status is linked to socially constructed subjectivities that can affect the individual’ s informationseeking behaviour. Qualitative analysis of data from two doctoral studies (collected through participant observation and 40 semi-structured interviews) illustrates the utility of social positioning theory as a framework for studying two specific health contexts: systematic lupus erythematosus, and twin pregnancy. Adopting a ‘ position’ involves the use of discursive practices which define the relations between self and others. Such practices frequently draw upon common social representations of particular phenomena (Van Langehove and Harre 1994). Our findings indicate that the visibility of health status is related to subject positioning, and that positioning theory offers insight into the mutually specifying correspondence between local discursive practices and styles of information behavior. The pregnant woman’ s expanding abdomen makes her health status evident to others, often positioning her as a willing recipient of advice and information (Browner and Press 1997). Cultural assumptions associated with “ twins” can both facilitate and constrain the woman’ s information seeking (“ Better you than me.” ). However, the stock of shared cultural understandings associated with lupus is comparatively sparse (Senecal 1991). Symptoms such as hair loss, skin rash, and weight gain may therefore lead to positions which are experienced by novice patients as stigmatizing (“ What’ s wrong with that woman?” ). Even when evident symptoms disappear, the stigmatized position can be maintained through secrecy (“ No one can tell I have lupus.” ). In these situations, information-seeking is relegated to the confidential encounters characteristic of expert disciplinary regimes. As a heuristic tool, then, positioning theory provides an opportunity for analysis of the means by which the information-seeking subject is configured through discursive encounters

    Hydrothermal oxide and nontronite deposits at Seamount 3, Wolf-Darwin lineament, Galapagos Archipelago, Ecuador

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    An unusual deposit of Fe-rich hydrothermal nontronite was recovered by remotely operated vehicle (ROV) from Seamount 3 of the Wolf-Darwin lineament, Galapagos Marine Reserve. X-ray diffraction, ICP-MS/ICP-AES, and SEM-EDS analyses show that this deposit is chemically and mineralogically similar to other deep-sea hydrothermal nontronites, indicating a formation temperature of about 30o to 50o Celsius. These Fe-Si-oxides and Fe-rich Al-poor nontronite deposits contain about 38-51 weight % SiO2 and 40-50 weight % Fe2O3. Although hydrothermal nontronite has been sampled at a number of sites by coring and dredging, this is the first in situ documentation of its sinuous, tubular structure on the sea floor. Image-analysis of ROV imagery suggests that this unusual pattern might be controlled by fluid pathways in the underlying pillow lavas

    Bilayer characteristics of a diether phosphonolipid analog of the major lung surfactant glycerophospholipid dipalmitoyl phosphatidylcholine.

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    Thermal and lyotropic phase behavior was studied by X-ray diffraction and differential scanning calorimetry for a diether phosphonolipid analog (DEPN-8) of the major lung surfactant glycerophospholipid dipalmitoyl phosphatidylcholine (DPPC). DEPN-8 differs in an ether, rather than an ester, bond at the acyl chain-backbone linkage and a headgroup phosphonate (isosteric methylene substitution) versus phosphate constituent. Analysis of lamellar diffraction maxima demonstrated that at high relative humidity (98%) and temperatures below the liquid crystal phase transition (approximately 45 degrees C), DEPN-8 formed interdigitated bilayers with a characteristic periodicity of 41.9-46.5 A. At low humidity the gel phase DEPN-8 bilayers were characteristic of a normal L beta phase with a periodicity equivalent to DPPC (57-59 A). Above the liquid crystal thermal phase transition, bilayer spacing for both DEPN-8 and DPPC was 51-52 A, characteristic of the L alpha phase. Complete assessments of both lamellar and in-plane X-ray scattering used to construct electron density profiles and structure-factor plots for DEPN-8 defined more fully the interdigitated bilayer state at high humidity and low temperature. Compared to DPPC, it is energetically favorable for DEPN-8 to form interdigitated bilayers under conditions of excess water and low temperature. The flexible character of the ether bonds in DEPN-8 allows increased hydrophobic interactions between acyl chains, without generating a steric penalty from the increased packing density of the molecules. Additionally, the ether bond and the phosphonate moiety may allow for more energetically favorable interactions between the choline portion of the headgroup and water. The DEPN-8 ether linkage may also contribute to the improved adsorption and film respreading found previously for this phosphonolipid compared to DPPC

    Space robotics: Recent accomplishments and opportunities for future research

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    The Langley Guidance, Navigation, and Control Technical Committee (GNCTC) was one of six technical committees created in 1991 by the Chief Scientist, Dr. Michael F. Card. During the kickoff meeting Dr. Card charged the chairmen to: (1) establish a cross-Center committee; (2) support at least one workshop in a selected discipline; and (3) prepare a technical paper on recent accomplishments in the discipline and on opportunities for future research. The Guidance, Navigation, and Control Committee was formed and selected for focus on the discipline of Space robotics. This report is a summary of the committee's assessment of recent accomplishments and opportunities for future research. The report is organized as follows. First is an overview of the data sources used by the committee. Next is a description of technical needs identified by the committee followed by recent accomplishments. Opportunities for future research ends the main body of the report. It includes the primary recommendation of the committee that NASA establish a national space facility for the development of space automation and robotics, one element of which is a telerobotic research platform in space. References 1 and 2 are the proceedings of two workshops sponsored by the committee during its June 1991, through May 1992 term. The focus of the committee for the June 1992 - May 1993 term will be to further define to the recommended platform in space and to add an additional discipline which includes aircraft related GN&C issues. To the latter end members performing aircraft related research will be added to the committee. (A preliminary assessment of future opportunities in aircraft-related GN&C research has been included as appendix A.
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