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

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

Comment on "Plasma ionization by annularly bounded helicon waves" [Phys . Plasmas 13, 063501 (2006)]

The neoclassical calculation of the helicon wave theory contains a fundamental flaw. Use is made of a proportional relationship between the magnetic field and its curl to derive the Helmholtz equation describing helicon wave propagation; however, by the fundamental theorem of Stokes, the curl of the magnetic field must be perpendicular to that portion of the field contributing to the local curl. Reexamination of the equations of motion indicates that only electromagnetic waves propagate through a stationary region of constant pressure in a fully ionized, neutral medium.Comment: 7 pages, 1 figure, to be published in Phys. Plasmas, http://link.aip.org/link/?PHPAEN/16/054701/

Opaline Microfossils in Some Michigan Soils

Author Institution: Department of Agronomy, University of Illinois, Urbana, Illinoi

Extracellular ATP inhibits agonist-induced mobilization of internal calcium in human platelets

AbstractOur previous studies have demonstrated that platelets possess ATP purinergic receptors in addition to the ADP, P2T, receptor. Occupancy of the P2 receptor by ATP inhibited agonist-induced platelet aggregation. This study demonstrated that the mechanism of inhibition may involve ATP inhibition of agonist-induced mobilization of internal calcium. Within the cardiovascular system, the ATP inhibition of calcium mobilization is unique to platelets. All other cell types in the cardiovascular system, where calcium mobilization is affected by extracellular ATP, responded with an increased mobilization as opposed to inhibition. The platelet inhibitory response to ATP was enhanced by the addition of an ATP generating system, creatine phosphate/phosphocreatine kinase. ATP and ATP analogues were found to inhibit calcium mobilization with a rank order of αβ-methylene ATP, βγ-methylene ATP ≈ ATP>benzoyl ATP>2 methylthio ATP which is a characteristic of P2X-like receptors. The inhibitory effect of ATP could be abrogated by prolonged treatment of platelets with the P2X desensitizing agent, αβ-methylene ATP. Also, UTP and CTP were approximately as effective inhibitors as ATP while GTP was not. ATP competition with ADP for the P2T receptor was excluded in studies with platelets derived from an aspirin-treated individual which were essentially insensitive to ADP. The agonist-induced calcium mobilization and inhibition by ATP occurred with the thromboxane A2 mimetic, U46619, collagen and thrombin; however, the kinetics of mobilization varied somewhat with the different agonists. The responses to extracellular ATP were independent of extracellular Ca2+, where 1 mM calcium or 0.3 mM EGTA was added to the reaction mixture. The inhibition of calcium mobilization coupled to inhibition of platelet aggregation by extracellular ATP may serve an important physiologic role. ATP, released from activated platelets at localized sites of vascular injury, may help to limit the size of the platelet plug-clot that, if left unregulated, could occlude the injured blood vessel

Phase diagram of the one-dimensional Holstein model of spinless fermions

The one-dimensional Holstein model of spinless fermions interacting with dispersionless phonons is studied using a new variant of the density matrix renormalisation group. By examining various low-energy excitations of finite chains, the metal-insulator phase boundary is determined precisely and agrees with the predictions of strong coupling theory in the anti-adiabatic regime and is consistent with renormalisation group arguments in the adiabatic regime. The Luttinger liquid parameters, determined by finite-size scaling, are consistent with a Kosterlitz-Thouless transition.Comment: Minor changes. 4 pages, 4 figures. To appear in Physical Review Letters 80 (1998) 560

Model-based reasoning for power system management using KATE and the SSM/PMAD

The overall goal of this research effort has been the development of a software system which automates tasks related to monitoring and controlling electrical power distribution in spacecraft electrical power systems. The resulting software system is called the Intelligent Power Controller (IPC). The specific tasks performed by the IPC include continuous monitoring of the flow of power from a source to a set of loads, fast detection of anomalous behavior indicating a fault to one of the components of the distribution systems, generation of diagnosis (explanation) of anomalous behavior, isolation of faulty object from remainder of system, and maintenance of flow of power to critical loads and systems (e.g. life-support) despite fault conditions being present (recovery). The IPC system has evolved out of KATE (Knowledge-based Autonomous Test Engineer), developed at NASA-KSC. KATE consists of a set of software tools for developing and applying structure and behavior models to monitoring, diagnostic, and control applications

Seagrass mapping synthesis: a resource for coastal management in the Great Barrier Reef World Heritage Area

This project provides an up to date synthesis of the available information on seagrass in the Great Barrier Reef World Heritage Area (GBRWHA). It brings together more than 30 years of spatial information and data collection into easy to use spatial GIS layers that provide key information on species, meadow type and age and reliability of the data. The project provides: Seagrass site and meadow-specific data in Geographic Information System (GIS) layers to provide seagrass data to inform research analysis and management advice. A site layer that includes >66,000 individual survey sites with information including latitude/longitude, Natural Resource Management region, site depth, seagrass presence/absence, dominant seagrass species, presence/absence of individual species, survey date, survey method, and data custodian. A meadow layer that includes 1169 individual and/or composite seagrass meadows with information including individual meadow persistence, meadow location (intertidal/subtidal), meadow density based on mean biomass and/or mean percent cover, meadow area, dominant seagrass species, seagrass species present, range of survey dates, survey method, and data custodian. Metadata to enable interpretation of the information and to identify the original data custodians for assistance with interpretation. Outcomes: This study consolidates all available seagrass spatial data for the GBRWHA collected from 1984 to December 2014 by the TropWATER Seagrass Group and CSIRO in a GIS database. It assembles and documents the state of spatial knowledge of seagrass in the GBRWHA. The spatial data is based on methods developed by TropWATER and CSIRO for seagrass habitat surveys of subtidal meadows, and TropWATER methods for intertidal surveys. Methods include sampling by boat (free divers, underwater video camera, grabs, sled with net sampling), helicopter and walking. 447,530 hectares of seagrasses were mapped (modelled deep water seagrass areas are not included in area figures in this report) within the GBRWHA; much of which provides habitat for commercial and traditional fishery species, and an important food resource for dugong and green turtle populations. Data is included for twelve seagrass species from three families. Seagrass was present at 39% of all sites visited. The study identifies areas where much of the data available for management is more than 20 years old or where there are specific habitats unsurveyed. Large areas of central and northern Queensland require updating. Several key habitat types such as reef platform seagrass meadows are poorly represented in the data

Foliar herbicide control of sticky florestina (Florestina tripteris DC.)

Sticky florestina (Florestina tripteris DC.) is an annual exotic weed that has become naturalised near the townships of Tambo and Barcaldine in central western Queensland, Australia. Three experiments conducted near Barcaldine identified foliar herbicides effective in killing sticky florestina plants and in providing residual activity to reduce recruitment from the soil seed bank. An initial chemical screening experiment evaluated the efficacy of 28 herbicide treatments. The most promising herbicides were then further evaluated in two response-rate experiments. Overall, 2,4-D/picloram, aminopyralid/fluroxypyr, clopyralid, metsulfuron-methyl and triclopyr/picloram proved to be the most effective selective herbicides. Two of these, metsulfuron-methyl at 18 g active ingredient (a.i) ha–1 and 2,4-D + picloram at 900 g a.i. ha–1 + 225 g a.i. ha–1 have now been included in a minor use permit (PER11920) with the Australian Pesticides and Veterinary Medicines Authority (APVMA) for the control of sticky florestina in pasture, stock route, roadside and non-crop situations using both spot and boom-spray applications (APVMA 2010). The permit also allows the use of 2,4-D amine for the control of seedlings only

Foliar herbicide control of sticky florestina (Florestina tripteris DC.)

Sticky florestina (Florestina tripteris DC.) is an annual exotic weed that has become naturalised near the townships of Tambo and Barcaldine in central western Queensland, Australia. Three experiments conducted near Barcaldine identified foliar herbicides effective in killing sticky florestina plants and in providing residual activity to reduce recruitment from the soil seed bank. An initial chemical screening experiment evaluated the efficacy of 28 herbicide treatments. The most promising herbicides were then further evaluated in two response-rate experiments. Overall, 2,4-D/picloram, aminopyralid/fluroxypyr, clopyralid, metsulfuron-methyl and triclopyr/picloram proved to be the most effective selective herbicides. Two of these, metsulfuron-methyl at 18 g active ingredient (a.i) ha–1 and 2,4-D + picloram at 900 g a.i. ha–1 + 225 g a.i. ha–1 have now been included in a minor use permit (PER11920) with the Australian Pesticides and Veterinary Medicines Authority (APVMA) for the control of sticky florestina in pasture, stock route, roadside and non-crop situations using both spot and boom-spray applications (APVMA 2010). The permit also allows the use of 2,4-D amine for the control of seedlings only

Ionic and electronic properties of the topological insulator Bi2_2Te2_2Se investigated using β\beta-detected nuclear magnetic relaxation and resonance of 8^8Li

We report measurements on the high temperature ionic and low temperature electronic properties of the 3D topological insulator Bi$_2$Te$_2$Se using ion-implanted $^8$Li $\beta$-detected nuclear magnetic relaxation and resonance. With implantation energies in the range 5-28 keV, the probes penetrate beyond the expected range of the topological surface state, but are still within 250 nm of the surface. At temperatures above ~150 K, spin-lattice relaxation measurements reveal isolated $^8$Li$^{+}$ diffusion with an activation energy $E_{A} = 0.185(8)$ eV and attempt frequency $\tau_{0}^{-1} = 8(3) \times 10^{11}$ s$^{-1}$ for atomic site-to-site hopping. At lower temperature, we find a linear Korringa-like relaxation mechanism with a field dependent slope and intercept, which is accompanied by an anomalous field dependence to the resonance shift. We suggest that these may be related to a strong contribution from orbital currents or the magnetic freezeout of charge carriers in this heavily compensated semiconductor, but that conventional theories are unable to account for the extent of the field dependence. Conventional NMR of the stable host nuclei may help elucidate their origin.Comment: 17 pages, 12 figures, submitted to Phys. Rev.