1,341 research outputs found

    Capability in the digital: institutional media management and its dis/contents

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    This paper explores how social media spaces are occupied, utilized and negotiated by the British Military in relation to the Ministry of Defence’s concerns and conceptualizations of risk. It draws on data from the DUN Project to investigate the content and form of social media about defence through the lens of ‘capability’, a term that captures and describes the meaning behind multiple representations of the military institution. But ‘capability’ is also a term that we hijack and extend here, not only in relation to the dominant presence of ‘capability’ as a representational trope and the extent to which it is revealing of a particular management of social media spaces, but also in relation to what our research reveals for the wider digital media landscape and ‘capable’ digital methods. What emerges from our analysis is the existence of powerful, successful and critically long-standing media and reputation management strategies occurring within the techno-economic online structures where the exercising of ‘control’ over the individual – as opposed to the technology – is highly effective. These findings raise critical questions regarding the extent to which ‘control’ and management of social media – both within and beyond the defence sector – may be determined as much by cultural, social, institutional and political influence and infrastructure as the technological economies. At a key moment in social media analysis, then, when attention is turning to the affordances, criticisms and possibilities of data, our research is a pertinent reminder that we should not forget the active management of content that is being similarly, if not equally, effective

    Pseudoscalar Conversion and X-rays from the Sun

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    We investigate the detection of a pseudoscalar ϕ\phi that couples electromagnetically via an interaction 14gϕFF~{1\over4}g \phi F {\tilde F}. In particular, we focus on the conversion of pseudoscalars produced in the sun's interior in the presence of the sun's external magnetic dipole field and sunspot-related magnetic fields. We find that the sunspot approach is superior. Measurements by the SXT on the Yohkoh satellite can measure the coupling constant down to g=0.5g=0.5--1×1010GeV11 \times 10^{-10}\,\rm GeV^{-1}, provided the pseudoscalar mass m<7×106m < 7{\times} 10^{-6}\,eV, which makes it competitive with other astrophysical approaches.Comment: 15 pages, RevTex file. Figures available upon request to [email protected]. (please include full mailing address in request). Submitted to Physics Letters

    Similar dissection of sets

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    In 1994, Martin Gardner stated a set of questions concerning the dissection of a square or an equilateral triangle in three similar parts. Meanwhile, Gardner's questions have been generalized and some of them are already solved. In the present paper, we solve more of his questions and treat them in a much more general context. Let DRdD\subset \mathbb{R}^d be a given set and let f1,...,fkf_1,...,f_k be injective continuous mappings. Does there exist a set XX such that D=Xf1(X)...fk(X)D = X \cup f_1(X) \cup ... \cup f_k(X) is satisfied with a non-overlapping union? We prove that such a set XX exists for certain choices of DD and {f1,...,fk}\{f_1,...,f_k\}. The solutions XX often turn out to be attractors of iterated function systems with condensation in the sense of Barnsley. Coming back to Gardner's setting, we use our theory to prove that an equilateral triangle can be dissected in three similar copies whose areas have ratio 1:1:a1:1:a for a(3+5)/2a \ge (3+\sqrt{5})/2

    Interleukin-7 deficiency in rheumatoid arthritis: consequences for therapy-induced lymphopenia

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    We previously demonstrated prolonged, profound CD4+ T-lymphopenia in rheumatoid arthritis (RA) patients following lymphocyte-depleting therapy. Poor reconstitution could result either from reduced de novo T-cell production through the thymus or from poor peripheral expansion of residual T-cells. Interleukin-7 (IL-7) is known to stimulate the thymus to produce new T-cells and to allow circulating mature T-cells to expand, thereby playing a critical role in T-cell homeostasis. In the present study we demonstrated reduced levels of circulating IL-7 in a cross-section of RA patients. IL-7 production by bone marrow stromal cell cultures was also compromised in RA. To investigate whether such an IL-7 deficiency could account for the prolonged lymphopenia observed in RA following therapeutic lymphodepletion, we compared RA patients and patients with solid cancers treated with high-dose chemotherapy and autologous progenitor cell rescue. Chemotherapy rendered all patients similarly lymphopenic, but this was sustained in RA patients at 12 months, as compared with the reconstitution that occurred in cancer patients by 3–4 months. Both cohorts produced naïve T-cells containing T-cell receptor excision circles. The main distinguishing feature between the groups was a failure to expand peripheral T-cells in RA, particularly memory cells during the first 3 months after treatment. Most importantly, there was no increase in serum IL-7 levels in RA, as compared with a fourfold rise in non-RA control individuals at the time of lymphopenia. Our data therefore suggest that RA patients are relatively IL-7 deficient and that this deficiency is likely to be an important contributing factor to poor early T-cell reconstitution in RA following therapeutic lymphodepletion. Furthermore, in RA patients with stable, well controlled disease, IL-7 levels were positively correlated with the T-cell receptor excision circle content of CD4+ T-cells, demonstrating a direct effect of IL-7 on thymic activity in this cohort

    Sunspot rotation, filament, and flare: The event on 2000 February 10

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    We find that a sunspot with positive polarity had an obvious counter-clockwise rotation and resulted in the formation and eruption of an inverse S-shaped filament in NOAA active region (AR) 08858 from 2000 February 9 to 10. The sunspot had two umbrae which rotated around each other by 195 degrees within about twenty-four hours. The average rotation rate was nearly 8 degrees per hour. The fastest rotation in the photosphere took place during 14:00UT to 22:01UT on February 9, with the rotation rate of nearly 16 degrees per hour. The fastest rotation in the chromosphere and the corona took place during 15:28UT to 19:00UT on February 9, with the rotation rate of nearly 20 degrees per hour. Interestingly, the rapid increase of the positive magnetic flux just occurred during the fastest rotation of the rotating sunspot, the bright loop-shaped structure and the filament. During the sunspot rotation, the inverse S-shaped filament gradually formed in the EUV filament channel. The filament experienced two eruptions. In the first eruption, the filament rose quickly and then the filament loops carrying the cool and the hot material were seen to spiral into the sunspot counterclockwise. About ten minutes later, the filament became active and finally erupted. The filament eruption was accompanied with a C-class flare and a halo coronal mass ejection (CME). These results provide evidence that sunspot rotation plays an important role in the formation and eruption of the sigmoidal active-region filament.Comment: 20 pages, 9 figures, Accepted for publication in Ap

    Age-related differences in spontaneous trait judgments from facial appearance.

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    We tested whether there are age-related declines in detecting cues to trustworthiness, a skill that has been demonstrated to be rapid and automatic in younger adults. Young (age M = 21.17 years) and older (age M = 70.15 years) adults made criminal appearance judgments to unfamiliar faces, which were presented at a duration of either 100, 500, or 1000-ms. Participants’ response times and judgment confidence were recorded. Older compared to young adults were poorer at judging trustworthiness at 100-ms, and were slower overall in making their judgments. Further, the cues (i.e., perceptions of anger, trustworthiness, and happiness) underlying criminality judgments were the same across age groups. Judgment confidence increased with increasing exposure duration for both age groups, while older adults were less confident in their judgments overall than their young counterparts. The implications are discussed

    Stray-light contamination and spatial deconvolution of slit-spectrograph observations

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    Stray light caused by scattering on optical surfaces and in the Earth's atmosphere degrades the spatial resolution of observations. We study the contribution of stray light to the two channels of POLIS. We test the performance of different methods of stray-light correction and spatial deconvolution to improve the spatial resolution post-facto. We model the stray light as having two components: a spectrally dispersed component and a component of parasitic light caused by scattering inside the spectrograph. We use several measurements to estimate the two contributions: observations with a (partly) blocked FOV, a convolution of the FTS spectral atlas, imaging in the pupil plane, umbral profiles, and spurious polarization signal in telluric lines. The measurements allow us to estimate the spatial PSF of POLIS and the main spectrograph of the German VTT. We use the PSF for a deconvolution of both spectropolarimetric data and investigate the effect on the spectra. The parasitic contribution can be directly and accurately determined for POLIS, amounting to about 5%. We estimate a lower limit of about 10% across the full FOV for the dispersed stray light. In quiet Sun regions, the stray-light level from the close surroundings (d< 2") of a given spatial point is about 20%. The stray light reduces to below 2% at a distance of 20" from a lit area for both POLIS and the main spectrograph. A two-component model of the stray-light contributions seems to be sufficient for a basic correction of observed spectra. The instrumental PSF obtained can be used to model the off-limb stray light, to determine the stray-light contamination accurately for observation targets with large spatial intensity gradients such as sunspots, and also allows one to improve the spatial resolution of observations post-facto.Comment: 14 pages, 16 figures, accepted by A&A. Version V2 revised for language editin

    Developing autonomous learning in first year university students using perspectives from positive psychology

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    Autonomous learning is a commonly occurring learning outcome from university study, and it is argued that students require confidence in their own abilities to achieve this. Using approaches from positive psychology, this study aimed to develop confidence in first‐year university students to facilitate autonomous learning. Psychological character strengths were assessed in 214 students on day one at university. Two weeks later their top three strengths were given to them in study skills modules as part of a psycho‐educational intervention designed to increase their self‐efficacy and self‐esteem. The impact of the intervention was assessed against a control group of 40 students who had not received the intervention. The results suggested that students were more confident after the intervention, and that levels of autonomous learning increased significantly compared to the controls. Character strengths were found to be associated with self‐efficacy, self‐esteem and autonomous learning in ways that were theoretically meaningful

    Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data

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    We investigate how the divergence-free property of magnetic fields can be exploited to resolve the azimuthal ambiguity present in solar vector magnetogram data, by using line-of-sight and horizontal heliographic derivative information as approximated from discrete measurements. Using synthetic data we test several methods that each make different assumptions about how the divergence-free property can be used to resolve the ambiguity. We find that the most robust algorithm involves the minimisation of the absolute value of the divergence summed over the entire field of view. Away from disk centre this method requires the sign and magnitude of the line-of-sight derivatives of all three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure
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