Different Patterns of Chromospheric Evaporation in a Flaring Region Observed with Hinode/EIS

We investigate the chromospheric evaporation in the flare of 2007 January 16 using line profiles observed by the EUV Imaging Spectrometer (EIS) onboard Hinode. Three points at flare ribbons of different magnetic polarities are analyzed in detail. We find that the three points show different patterns of upflows and downflows in the impulsive phase of the flare. The spectral lines at the first point are mostly blue shifted, with the hotter lines showing a dominant blue-shifted component over the stationary one. At the second point, however, only weak upflows are detected; in stead, notable downflows appear at high temperatures (up to 2.5-5.0 MK). The third point is similar to the second one only that it shows evidence of multi-component downflows. While the evaporated plasma falling back down as warm rain is a possible cause of the redshifts at points 2 and 3, the different patterns of chromospheric evaporation at the three points imply existence of different heating mechanisms in the flaring active region.Comment: 18 pages, 7 figures, 2 tables. Accepted for publication in Ap

Is it possible to establish reference values for ankle muscle isokinetic strength? A meta-analytical study

BACKGROUND: The importance of measuring ankle muscle strength (AMS) has been demonstrated in a variety of clinical areas. Much data has been accumulated using the Cybex Norm isokinetic dynamometer but a uniform framework does not exist. OBJECTIVE: To identify pertinent studies which have used the Cybex Norm to measure AMS in order to establish reference values. METHODS: A narrative review of the literature was used to identify papers that have used the Cybex Norm to measure isokinetic concentric and eccentric AMS. RESULTS: Fifty five research papers were identified but each study used a different isokinetic protocol. CONCLUSIONS: It is not possible to produce AMS reference values due to the wide variation in data collection methods. This is therefore an area of research that needs further exploration

Evidence of Explosive Evaporation in a Microflare Observed by Hinode/EIS

We present a detailed study of explosive chromospheric evaporation during a microflare which occurred on 2007 December 7 as observed with the EUV Imaging Spectrometer (EIS) onboard Hinode. We find temperature-dependent upflows for lines formed from 1.0 to 2.5 MK and downflows for lines formed from 0.05 to 0.63 MK in the impulsive phase of the flare. Both the line intensity and the nonthermal line width appear enhanced in most of the lines and are temporally correlated with the time when significant evaporation was observed. Our results are consistent with the numerical simulations of flare models, which take into account a strong nonthermal electron beam in producing the explosive chromospheric evaporation. The explosive evaporation observed in this microflare implies that the same dynamic processes may exist in events with very different magnitudes.Comment: 14 pages, 8 figures. Accepted for publication in the Astrophysical Journa

Fundamental study in low-density gas dynamics Progress report, 1 Nov. 1968 - 30 Jun. 1969

Theoretical and experimental study of rarefied gas viscoseals in continuum to free molecular density range and speeds up to 30,000 rp

Matrix isolation study of the photolysis of cyanogen azide. The infrared and ultraviolet spectra of the free radical NCN

Infrared and ultraviolet absorption spectra of free radical in photolysis of cyanogen azid

We Could, but Should We? Ethical Considerations for Providing Access to GeoCities and Other Historical Digital Collections

We live in an era in which the ways that we can make sense of our past are evolving as more artifacts from that past become digital. At the same time, the responsibilities of traditional gatekeepers who have negotiated the ethics of historical data collection and use, such as librarians and archivists, are increasingly being sidelined by the system builders who decide whether and how to provide access to historical digital collections, often without sufficient reflection on the ethical issues at hand. It is our aim to better prepare system builders to grapple with these issues. This paper focuses discussions around one such digital collection from the dawn of the web, asking what sorts of analyses can and should be conducted on archival copies of the GeoCities web hosting platform that dates to 1994.This research was supported by the Natural Sciences and Engineering Research Council of Canada, the Social Sciences and Humanities Research Council of Canada, the US National Science Foundation (grants 1618695 and 1704369), the Andrew W. Mellon Foundation, Start Smart Labs, and Compute Canada

An assessment of Fe XX - Fe XXII emission lines in SDO/EVE data as diagnostics for high density solar flare plasmas using EUVE stellar observations

The Extreme Ultraviolet Variability Experiment (EVE) on the Solar Dynamics Observatory obtains extreme-ultraviolet (EUV) spectra of the full-disk Sun at a spectral resolution of ~1 A and cadence of 10 s. Such a spectral resolution would normally be considered to be too low for the reliable determination of electron density (N_e) sensitive emission line intensity ratios, due to blending. However, previous work has shown that a limited number of Fe XXI features in the 90-60 A wavelength region of EVE do provide useful N_e-diagnostics at relatively low flare densities (N_e ~ 10^11-10^12 cm^-3). Here we investigate if additional highly ionised Fe line ratios in the EVE 90-160 A range may be reliably employed as N_e-diagnostics. In particular, the potential for such diagnostics to provide density estimates for high N_e (~10^13 cm^-3) flare plasmas is assessed. Our study employs EVE spectra for X-class flares, combined with observations of highly active late-type stars from the Extreme Ultraviolet Explorer (EUVE) satellite plus experimental data for well-diagnosed tokamak plasmas, both of which are similar in wavelength coverage and spectral resolution to those from EVE. Several ratios are identified in EVE data which yield consistent values of electron density, including Fe XX 113.35/121.85 and Fe XXII 114.41/135.79, with confidence in their reliability as N_e-diagnostics provided by the EUVE and tokamak results. These ratios also allow the determination of density in solar flare plasmas up to values of ~10^13 cm^-3.Comment: 7 pages, 3 figures, 2 tables, MNRAS in pres

Orexin-1 receptor-cannabinoid CB1 receptor heterodimerization results in both ligand-dependent and -independent coordinated alterations of receptor localization and function

Following inducible expression in HEK293 cells, the human orexin-1 receptor was targeted to the cell surface but became internalized following exposure to the peptide agonist orexin A. By contrast, constitutive expression of the human cannabinoid CB1 receptor resulted in a predominantly punctate, intracellular distribution pattern consistent with spontaneous, agonistindependent internalization. Expression of the orexin-1 receptor in the presence of the CB1 receptor resulted in both receptors displaying the spontaneous internalization phenotype. Single cell fluorescence resonance energy transfer imaging indicated the two receptors were present as heterodimers/oligomers in intracellular vesicles. Addition of the CB1 receptor antagonist SR-141716A to cells expressing only the CB1 receptor resulted in re-localization of the receptor to the cell surface. Although SR-141716A has no significant affinity for the orexin-1 receptor, in cells co-expressing the CB1 receptor, the orexin-1 receptor was also re-localized to the cell surface by treatment with SR-141716A. Treatment of cells co-expressing the orexin-1 and CB1 receptors with the orexin-1 receptor antagonist SB-674042 also resulted in re-localization of both receptors to the cell surface. Treatment with SR-141716A resulted in decreased potency of orexin A to activate the mitogen-activated protein kinases ERK1/2 only in cells co-expressing the two receptors. Treatment with SB-674042 also reduced the potency of a CB1 receptor agonist to phosphorylate ERK1/2 only when the two receptors were co-expressed. These studies introduce an entirely novel pharmacological paradigm, whereby ligands modulate the function of receptors for which they have no significant inherent affinity by acting as regulators of receptor heterodimers