Hα Doppler shifts in a tornado in the solar corona

Context. High resolution movies in 193 Å from the Atmospheric Imaging Assembly (AIA) on the Solar Dynamic Observatory (SDO) show apparent rotation in the leg of a prominence observed during a coordinated campaign. Such structures are commonly referred to as tornadoes. Time-distance intensity diagrams of the AIA data show the existence of oscillations suggesting that the structure is rotating. Aims. The aim of this paper is to understand if the cool plasma at chromospheric temperatures inside the tornado is rotating around its central axis. Methods. The tornado was also observed in Hα with a cadence of 30 s by the MSDP spectrograph, operating at the Solar Tower in Meudon. The MSDP provides sequences of simultaneous spectra in a 2D field of view from which a cube of Doppler velocity maps is retrieved. Results. The Hα Doppler maps show a pattern with alternatively blueshifted and redshifted areas of 5 to 10′′ wide. Over time the blueshifted areas become redshifted and vice versa, with a quasi-periodicity of 40 to 60 min. Weaker amplitude oscillations with periods of 4 to 6 min are superimposed onto these large period oscillations. Conclusions. The Doppler pattern observed in Hα cannot be interpreted as rotation of the cool plasma inside the tornado. The Hα velocity observations give strong constraints on the possible interpretations of the AIA tornado

Open questions on prominences from coordinated observations by IRIS, Hinode, SDO/AIA, THEMIS, and the Meudon/MSDP

Context. A large prominence was observed on September 24, 2013, for three hours (12:12 UT -15:12 UT) with the newly launched (June 2013) Interface Region Imaging Spectrograph (IRIS), THEMIS (Tenerife), the Hinode Solar Optical Telescope (SOT), the Solar Dynamic Observatory Atmospheric Imaging Assembly (SDO/AIA), and the Multichannel Subtractive Double Pass spectrograph (MSDP) in the Meudon Solar Tower. Aims. The aim of this work is to study the dynamics of the prominence fine structures in multiple wavelengths to understand their formation. Methods. The spectrographs IRIS and MSDP provided line profiles with a high cadence in Mg II and in Halpha lines. Results. The magnetic field is found to be globally horizontal with a relatively weak field strength (8-15 Gauss). The Ca II movie reveals turbulent-like motion that is not organized in specific parts of the prominence. On the other hand, the Mg II line profiles show multiple peaks well separated in wavelength. Each peak corresponds to a Gaussian profile, and not to a reversed profile as was expected by the present non-LTE radiative transfer modeling. Conclusions. Turbulent fields on top of the macroscopic horizontal component of the magnetic field supporting the prominence give rise to the complex dynamics of the plasma. The plasma with the high velocities (70 km/s to 100 km/s if we take into account the transverse velocities) may correspond to condensation of plasma along more or less horizontal threads of the arch-shape structure visible in 304 A. The steady flows (5 km/s) would correspond to a more quiescent plasma (cool and prominence-corona transition region) of the prominence packed into dips in horizontal magnetic field lines. The very weak secondary peaks in the Mg II profiles may reflect the turbulent nature of parts of the prominence.Comment: 15 pages, 14 figure

Impact of audio text, visual text and cueing on cognitive load and performance

The focus of this study is to examine the effects of cognitive load theory, particularly the effects of redundancy and cueing, when learning from text and diagrams. A review of the literature on cognitive load and cueing is presented in three sections; the literature on split-attention and redundancy, studies investigating the modality effect, and literature of signaling or cueing related to performance and cognitive load in instructional design. In one experiment three hypotheses were tested; that novice participants would have lower cognitive load, higher recall and higher performance with a) cued text vs. plain text, b) audio text vs. visual text, and c) cued audio text vs. plain audio text. The study sought to confirm existing research on the effects of narration vs. written text on cognitive load, and to extend cognitive load research into the area of signaled text and narration. Although the results for the 3 hypotheses were not statistically significant, there was an indication of a practical trend supporting the effectiveness if cued audio text, where higher scores on the performance test were observed for these participants. Also, learner preferences were measured for the different text presentation methods, and a preference for cueing was strongly indicated, although no preference for audio text vs. visual text was identified. These findings contribute to the theory and practice surrounding the design and development of instruction; particularly instruction that is designed to be offered via the Internet, or web-based instruction. Further exploration into cued audio text, plain audio text, cued visual text and cued audio text, and their impact on cognitive load, recall and performance in instruction is a rich area for future research

Filament eruption connected to protospheric activity

Two cases of activation of filaments that occured in regions of intense magnetic activity was studied. The simultaneous observations from Debrecen Observatory (white light and H alpha filtergram), and from Meudon Observatory (magnetogram, MSDP dopplergram and intensity maps in H alpha) gave a complementary set of data from which can be produced evidence of the influence of the photospheric magnetic field on the destabilization process of the filaments. On June 22, 1980, the eruption of the filament is associated with the motion of pores, which are manifestations of emerging flux knots. On September 3, 1980, the twisting motions in the filament are associated to the birth of a pore in its neighborhood. These observations are discussed

Exploration of long-period oscillations in an Hα prominence

Context. In previous work, we studied a prominence which appeared like a tornado in a movie made from 193 Å filtergrams obtained with the Atmospheric Imaging Assembly (AIA) imager aboard the Solar Dynamics Observatory (SDO). The observations in Hα obtained simultaneously during two consecutive sequences of one hour with the Multi-channel Subtractive Double Pass Spectrograph (MSDP) operating at the solar tower in Meudon showed that the cool plasma inside the tornado was not rotating around its vertical axis. Furthermore, the evolution of the Dopplershift pattern suggested the existence of oscillations of periods close to the time-span of each sequence. Aims. The aim of the present work is to assemble the two sequences of Hα observations as a full data set lasting two hours to confirm the existence of oscillations, and determine their nature. Methods. After having coaligned the Doppler maps of the two sequences, we use a Scargle periodogram analysis and cosine fitting to compute the periods and the phase of the oscillations in the full data set. Results. Our analysis confirms the existence of oscillations with periods between 40 and 80 min. In the Dopplershift maps, we identify large areas with strong spectral power. In two of them, the oscillations of individual pixels are in phase. However, in the top area of the prominence, the phase is varying slowly, suggesting wave propagation. Conclusions. We conclude that the prominence does not oscillate as a whole structure but exhibits different areas with their own oscillation periods and characteristics: standing or propagating waves. We discuss the nature of the standing oscillations and the propagating waves. These can be interpreted in terms of gravito-acoustic modes and magnetosonic waves, respectively

Qualitative focus group study investigating experiences of accessing and engaging with social care services: perspectives of carers from diverse ethnic groups caring for stroke survivors

OBJECTIVES: Informal carers, often family members, play a vital role in supporting stroke survivors with post-stroke disability. As populations age, numbers of carers overall and those from minority ethnic groups in particular, are rising. Carers from all ethnic groups, but especially those from black and minority ethnic groups frequently fail to access support services, making understanding their experiences important. The study therefore explored the experiences of carers of stroke survivors aged 45+ years from 5 ethnic groups in accessing and receiving social care services after hospital discharge. DESIGN: This qualitative study used 7 recorded focus groups with informal carers of stroke survivors. Data were analysed thematically focusing on similarities and differences between ethnic groups. SETTING: Carers were recruited from voluntary sector organisations supporting carers, stroke survivors and black and minority ethnic groups in the UK. PARTICIPANTS: 41 carers from 5 ethnic groups (Asian Indian, Asian Pakistani, black African, black Caribbean, white British) participated in the focus groups. RESULTS: Several interconnected themes were identified including: the service gap between hospital discharge and home; carers as the best person to care and cultural aspects of caring and using services. Many themes were common to all the included ethnic groups but some related to specific groups. CONCLUSIONS: Across ethnic groups there were many similarities in the experiences of people caring for stroke survivors with complex, long-term care needs. Accessing services demands effort and persistence on carers' part. If carers believe services are unsatisfactory or that they, rather than formal services, should be providing support for stroke survivors, they are unlikely to persist in their efforts. Cultural and language differences add to the challenges black and minority ethnic group carers face

Estimation of solar prominence magnetic fields based on the reconstructed 3D trajectories of prominence knots

We present an estimation of the lower limits of local magnetic fields in quiescent, activated, and active (surges) promineces, based on reconstructed 3-dimensional (3D) trajectories of individual prominence knots. The 3D trajectories, velocities, tangential and centripetal accelerations of the knots were reconstructed using observational data collected with a single ground-based telescope equipped with a Multi-channel Subtractive Double Pass imaging spectrograph. Lower limits of magnetic fields channeling observed plasma flows were estimated under assumption of the equipartition principle. Assuming approximate electron densities of the plasma n_e = 5*10^{11} cm^{-3} in surges and n_e = 5*10^{10} cm^{-3} in quiescent/activated prominences, we found that the magnetic fields channeling two observed surges range from 16 to 40 Gauss, while in quiescent and activated prominences they were less than 10 Gauss. Our results are consistent with previous detections of weak local magnetic fields in the solar prominences.Comment: 14 pages, 12 figures, 1 tabl

Digital Learning and Development Environment: NEH White Paper

Wayne State University’s Digital Learning and Development Environment was a research and development project aimed at developing a prototype for a systematic approach to digital learning using image repositories. The repositories used in the project were two of the Wayne State University Library System’s (WSULS) Digital Collections: Virtual Motor City and Digital Dress. The Collections are web portals providing universal access to digitized objects of cultural history from dispersed holdings of WSULS’s institutional partners. The project integrates easy-to-use technical tools with instructional design principles and resources for digital teaching and learning. The result is a replicable web environment where faculty and students can use accessible tools to easily create Digital Learning Objects (DLOs) from collections of digital images. The unique design of the Environment places images from the Library\u27s Digital Collections in context with a tool that downloads the images into a learning object and also provides expert advice in the design of effective digital media for instructional presentations and assignments. Award Dates: 01/09/2009 – 08/31/2009 (no-cost extension until 10/31/2009) Outright Funds: $50,00

Multi-parameter phenotyping of platelets and characterisation of the effects of agonists using machine learning

Platelet function is driven by the expression of specialised surface markers. The concept of distinct circulating sub-populations of platelets has emerged in recent years, but their exact nature remains debatable. Objective To design a spectral flow cytometry-based phenotyping workflow to provide a more comprehensive characterisation, at a global and individual level, of surface markers in resting and activated healthy platelets. Secondly, to apply this workflow to investigate how responses differ according to platelet age. Methods A 14-marker flow cytometry panel was developed and applied to vehicle- or agonist-stimulated platelet-rich plasma and whole blood samples obtained from healthy volunteers, or to platelets sorted according to SYTO-13 staining intensity as an indicator of platelet age. Data were analysed using both user-led and independent approaches incorporating novel machine learning-based algorithms. Results The assay detected differences in marker expression in healthy platelets, at rest and on agonist activation, in both platelet rich plasma and whole blood samples, that are consistent with the literature. Machine learning identified stimulated populations of platelets with high accuracy (>80%). Similarly, machine learning differentiation between young and old platelet populations achieved 76% accuracy, primarily weighted by FSC-A, CD41, SSC-A, GPVI, CD61, and CD42b expression patterns. Conclusions Our approach provides a powerful phenotypic assay coupled with robust bioinformatic and machine learning workflows for deep analysis of platelet sub-populations. Cleave-able receptors, GPVI and CD42b, contribute to defining shared and unique sub-populations. This adoptable, low-volume approach will be valuable in deep characterisation of platelets in disease

Integrated transcriptomics and metabolomics reveal signatures of lipid metabolism dysregulation in HepaRG liver cells exposed to PCB 126.

Chemical pollutant exposure is a risk factor contributing to the growing epidemic of non-alcoholic fatty liver disease (NAFLD) affecting human populations that consume a western diet. Although it is recognized that intoxication by chemical pollutants can lead to NAFLD, there is limited information available regarding the mechanism by which typical environmental levels of exposure can contribute to the onset of this disease. Here, we describe the alterations in gene expression profiles and metabolite levels in the human HepaRG liver cell line, a validated model for cellular steatosis, exposed to the polychlorinated biphenyl (PCB) 126, one of the most potent chemical pollutants that can induce NAFLD. Sparse partial least squares classification of the molecular profiles revealed that exposure to PCB 126 provoked a decrease in polyunsaturated fatty acids as well as an increase in sphingolipid levels, concomitant with a decrease in the activity of genes involved in lipid metabolism. This was associated with an increased oxidative stress reflected by marked disturbances in taurine metabolism. A gene ontology analysis showed hallmarks of an activation of the AhR receptor by dioxin-like compounds. These changes in metabolome and transcriptome profiles were observed even at the lowest concentration (100 pM) of PCB 126 tested. A decrease in docosatrienoate levels was the most sensitive biomarker. Overall, our integrated multi-omics analysis provides mechanistic insight into how this class of chemical pollutant can cause NAFLD. Our study lays the foundation for the development of molecular signatures of toxic effects of chemicals causing fatty liver diseases to move away from a chemical risk assessment based on in vivo animal experiments