2,297 research outputs found
Looking Back to Move Forward with Guided Reading
Guided reading is used in classrooms across the country and, while it is fairly new, it is anything but revolutionary. In this article, and in honor of the 50th volume of Reading Horizons, the authors take a look back at the 50-year history of this practice, provide a definition of guided reading, analyze what caused the practice to change, and discuss their own perspectives and predict the future of guided reading
Signatures of Interchange Reconnection: STEREO, ACE and Hinode Observations Combined
Combining STEREO, ACE and Hinode observations has presented an opportunity to
follow a filament eruption and coronal mass ejection (CME) on the 17th of
October 2007 from an active region (AR) inside a coronal hole (CH) into the
heliosphere. This particular combination of `open' and closed magnetic
topologies provides an ideal scenario for interchange reconnection to take
place. With Hinode and STEREO data we were able to identify the emergence time
and type of structure seen in the in-situ data four days later. On the 21st,
ACE observed in-situ the passage of an ICME with `open' magnetic topology. The
magnetic field configuration of the source, a mature AR located inside an
equatorial CH, has important implications for the solar and interplanetary
signatures of the eruption. We interpret the formation of an `anemone'
structure of the erupting AR and the passage in-situ of the ICME being
disconnected at one leg, as manifested by uni-directional suprathermal electron
flux in the ICME, to be a direct result of interchange reconnection between
closed loops of the CME originating from the AR and `open' field lines of the
surrounding CH.Comment: 13 pages, 13 figures, accepted Annales Geophysica
Statistics of counter-streaming solar wind suprathermal electrons at solar minimum : STEREO observations
Previous work has shown that solar wind suprathermal electrons can display a number of features in terms of their anisotropy. Of importance is the occurrence of counter-streaming electron patterns, i.e., with "beams" both parallel and anti-parallel to the local magnetic field, which is believed to shed light on the heliospheric magnetic field topology. In the present study, we use STEREO data to obtain the statistical properties of counter-streaming suprathermal electrons (CSEs) in the vicinity of corotating interaction regions (CIRs) during the period March–December 2007. Because this period corresponds to a minimum of solar activity, the results are unrelated to the sampling of large-scale coronal mass ejections, which can lead to CSE owing to their closed magnetic field topology. The present study statistically confirms that CSEs are primarily the result of suprathermal electron leakage from the compressed CIR into the upstream regions with the combined occurrence of halo depletion at 90° pitch angle. The occurrence rate of CSE is found to be about 15–20% on average during the period analyzed (depending on the criteria used), but superposed epoch analysis demonstrates that CSEs are preferentially observed both before and after the passage of the stream interface (with peak occurrence rate >35% in the trailing high speed stream), as well as both inside and outside CIRs. The results quantitatively show that CSEs are common in the solar wind during solar minimum, but yet they suggest that such distributions would be much more common if pitch angle scattering were absent. We further argue that (1) the formation of shocks contributes to the occurrence of enhanced counter-streaming sunward-directed fluxes, but does not appear to be a necessary condition, and (2) that the presence of small-scale transients with closed-field topologies likely also contributes to the occurrence of counter-streaming patterns, but only in the slow solar wind prior to CIRs
Prenatal diagnosis of sirenomelia in the second trimester of pregnancy using two-dimensional ultrasound, three-dimensional ultrasound and magnetic resonance imaging
Relatives' Experiences of Frontal-Variant Frontotemporal Dementia
In this article we address how relatives of people with frontal-variant frontotemporal dementia (fvFTD) experience the illness and how it impacts their lives. We interviewed 6 participants and carried out interpretative phenomenological analysis. We report on 11 themes that reflect distinctive challenges. Five themes relate to witnessing bizarre and strange changes: changed appetites and drives, loss of planning ability, loss of inhibition leading to social embarrassment, risky behavior, and communication problems. Four relate to managing these changes and two to the impact on the person and his or her relationships. Relatives must live with unusual changes in the person with fvFTD and the stigma this carries in social settings. They learn to act assertively for their relatives and put effort into promoting quality of life, using strategies adapted for fvFTD. Relatives grieve the loss of the person with fvFTD and their mutual relationship, but nonetheless find sources of solace and hope
Transport properties of copper phthalocyanine based organic electronic devices
Ambipolar charge carrier transport in Copper phthalocyanine (CuPc) is studied
experimentally in field-effect transistors and metal-insulator-semiconductor
diodes at various temperatures. The electronic structure and the transport
properties of CuPc attached to leads are calculated using density functional
theory and scattering theory at the non-equilibrium Green's function level. We
discuss, in particular, the electronic structure of CuPc molecules attached to
gold chains in different geometries to mimic the different experimental setups.
The combined experimental and theoretical analysis explains the dependence of
the mobilityand the transmission coefficient on the charge carrier type
(electrons or holes) and on the contact geometry. We demonstrate the
correspondence between our experimental results on thick films and our
theoretical studies of single molecule contacts. Preliminary results for
fluorinated CuPc are discussed.Comment: 18 pages, 16 figures; to be published in Eur. Phys. J. Special Topic
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Intermittent release of transients in the slow solar wind: 2. In situ evidence
In paper 1, we showed that the Heliospheric Imager (HI) instruments on the pair of NASA STEREO spacecraft can be used to image the streamer belt and, in particular, the variability of the slow solar wind which originates near helmet streamers. The observation of intense intermittent transient outflow by HI implies that the corresponding in situ observations of the slow solar wind and corotating interaction regions (CIRs) should contain many signatures of transients. In the present paper, we compare the HI observations with in situ measurements from the STEREO and ACE spacecraft. Analysis of the solar wind ion, magnetic field, and suprathermal electron flux measurements from
the STEREO spacecraft reveals the presence of both closed and partially disconnected interplanetary magnetic field lines permeating the slow solar wind. We predict that one of the transients embedded within the second CIR (CIR‐D in paper 1) should impact the near‐Earth ACE spacecraft. ACE measurements confirm the presence of a transient at the time of CIR passage; the transient signature includes helical magnetic fields and bidirectional suprathermal electrons. On the same day, a strahl electron dropout is observed at STEREO‐B, correlated with the passage of a high plasma beta structure. Unlike ACE, STEREO‐B observes the transient a few hours ahead of the CIR. STEREO‐A, STEREO‐B, and ACE spacecraft observe very different slow solar wind properties ahead of and during the CIR analyzed in this paper, which we associate with the intermittent release of transients
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