660 research outputs found

    Trajectories of Explorers 33, 34 and 35, July 1966 - July 1968

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    Solar ecliptic plane projections on Explorer 33, 34, and 35 satellite orbit

    On the multispacecraft determination of periodic surface wave phase speeds and wavelengths

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    Observations of surface waves on the magnetopause indicate a wide range of phase velocities and wavelengths. Their multispacecraft analysis allows a more precise determination of wave characteristics than ever before and reveal shortcomings of approximations to the phase speed that take a predetermined fraction of the magnetosheath speed or the average flow velocity in the boundary layer. We show that time lags between two or more spacecraft can give a qualitative upper estimate, and we confirm the unreliability of flow approximations often used by analyzing a few cases. Using two‐point distant magnetic field observations and spectral analysis of the tailward magnetic field component, we propose an alternative method to estimate the wavelength and phase speed at a single spacecraft from a statistical fit to the data at the other site

    Recovery phase of magnetic storms induced by different interplanetary drivers

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    Statistical analysis of Dst behaviour during recovery phase of magnetic storms induced by different types of interplanetary drivers is made on the basis of OMNI data in period 1976-2000. We study storms induced by ICMEs (including magnetic clouds (MC) and Ejecta) and both types of compressed regions: corotating interaction regions (CIR) and Sheaths. The shortest, moderate and longest durations of recovery phase are observed in ICME-, CIR-, and Sheath-induced storms, respectively. Recovery phases of strong (Dstmin<−100Dst_{min} < -100 nT) magnetic storms are well approximated by hyperbolic functions Dst(t)=a/(1+t/τh)Dst(t)= a/(1+t/\tau_h) with constant τh\tau_h times for all types of drivers while for moderate (−100<Dstmin<−50-100 < Dst_{min} < -50 nT) storms DstDst profile can not be approximated by hyperbolic function with constant τh\tau_h because hyperbolic time τh\tau_h increases with increasing time of recovery phase. Relation between duration and value DstminDst_{min} for storms induced by ICME and Sheath has 2 parts: DstminDst_{min} and duration correlate at small durations while they anticorrelate at large durations.Comment: 18 pages, 4 figures, 2 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams

    Geoeffectiveness and efficiency of CIR, Sheath and ICME in generation of magnetic storms

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    We investigate relative role of various types of solar wind streams in generation of magnetic storms. On the basis of the OMNI data of interplanetary measurements for the period of 1976-2000 we analyze 798 geomagnetic storms with Dst < -50 nT and their interplanetary sources: corotating interaction regions (CIR), interplanetary CME (ICME) including magnetic clouds (MC) and Ejecta and compression regions Sheath before both types of ICME. For various types of solar wind we study following relative characteristics: occurrence rate; mass, momentum, energy and magnetic fluxes; probability of generation of magnetic storm (geoeffectiveness) and efficiency of process of this generation. Obtained results show that despite magnetic clouds have lower occurrence rate and lower efficiency than CIR and Sheath they play an essential role in generation of magnetic storms due to higher geoeffectiveness of storm generation (i.e higher probability to contain large and long-term southward IMF Bz component).Comment: 23 pages, 4 figures, 3 tables, submitted to JGR special issue "Response of Geospace to High-Speed Streams

    “I know my body better than anyone else” Perspectives of people who inject drugs on antimicrobial treatment decision making for serious infections

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    Introduction: ‱ Few studies have examined the perspectives of patients with lived experience regarding outpatient treatment options for injection drug use (IDU) associated infections. ‱ We sought to better understand the perspectives of both community partners with lived experience who work with people who inject drugs (PWID) and hospitalized patients with IDU-associated infections on shared treatment decision making.https://knowledgeconnection.mainehealth.org/lambrew-retreat-2023/1009/thumbnail.jp

    Never Mind the Gap: Formative Assessment Confronted with Dewey’s and Gadamer’s Concept of Experience

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    The notion of “closing the learning gap” is widely used in the conceptualisation of formative assessment. It builds on an unarticulated assumption that students' learning can and should be controlled towards predefined outcomes. This article discusses this control assumption in the light of the concept of the American philosopher John Dewey and the German philosopher Hans‐Georg Gadamer. Their conceptualisation challenges the idea of learning as a linear and controllable process that results in stable and predictable outcomes. Using the concept of experience, we argue that learning follows a continuous circular movement where previous experiences condition future interpretations and that every experience changes the subject. This process of change is both unpredictable and diverse and requires that attention is paid to the uniqueness of each situation and to students as subjects. Following the discussion, we propose a model for considering the extensiveness and rigidity of formative assessment practices and that authors pay attention to whether they conceptualise formative assessment in a way that promotes student and teacher “gap closing” and control.publishedVersio
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