2,676 research outputs found
Civic action on social media: fostering digital media literacy and epistemic cognition in the classroom
Social media has become a dominant force in civic life amid widespread concerns about its role in political polarisation and in the spread of misinformation. To prepare citizens to take on these challenges, we need civic education that teaches youth to be capable and responsible consumers, conveyors and producers of online information. To do so, teachers must position students as epistemic agents, fostering the skills they need to engage with online information. In this article, we present the first iteration of a design-based research project on social media and civic action. The project prepares high school students in rural, urban and suburban settings located in Northern California (USA) to engage with issues that resonate with them, to critically examine information about these issues from online sources and to use social media as a vehicle to connect with, inform and mobilise the public. We present the basic design principles that teachers have used to support apt epistemic performance, focusing on the epistemic aims (creating knowledge products that inspire civic action), ideals (taking personal responsibility for the accuracy of information when posting) and reliable processes (sourcing, fact checking and correctly representing information) embedded in their units of instruction. Drawing on teacher interviews and curriculum, we explore the affordances of the curriculum to promote civic action by leveraging student engagement in social media, while also challenging them to critically examine how knowledge is produced and disseminated on social media. We conclude with a discussion of how this work intersects with the aims and methods of social pedagogy
Developement of real time diagnostics and feedback algorithms for JET in view of the next step
Real time control of many plasma parameters will be an essential aspect in
the development of reliable high performance operation of Next Step Tokamaks.
The main prerequisites for any feedback scheme are the precise real-time
determination of the quantities to be controlled, requiring top quality and
highly reliable diagnostics, and the availability of robust control algorithms.
A new set of real time diagnostics was recently implemented on JET to prove the
feasibility of determining, with high accuracy and time resolution, the most
important plasma quantities. With regard to feedback algorithms, new
model–based controllers were developed to allow a more robust control of
several plasma parameters. Both diagnostics and algorithms were successfully
used in several experiments, ranging from H-mode plasmas to configuration with
ITBs. Since elaboration of computationally heavy measurements is often
required, significant attention was devoted to non-algorithmic methods like
Digital or Cellular Neural/Nonlinear Networks. The real time hardware and
software adopted architectures are also described with particular attention to
their relevance to ITER.Comment: 12th International Congress on Plasma Physics, 25-29 October 2004,
Nice (France
Stressful Life Events Among Incarcerated Women and Men: Association With Depression, Loneliness, Hopelessness, and Suicidality
Background: Justice-involved populations report a higher than average number of pre-incarceration stressful life events. However, few studies have described stressful life events which occur during incarceration, explored gender differences in these events, or evaluated the effect of these events on well-being. Method: This study draws from a sample of male and female adults incarcerated in 6 prison facilities across two states (n = 160) to identify the number and type of stressful life events they experienced during incarceration, gender differences in stressful events, and the relationship between stressful life events and markers of well-being (i.e., depression, hopelessness, loneliness, suicidality). We also examined whether perceived social support would buffer the relationship between stressful events and well-being outcomes. Results: Participants on average reported experiencing 4 stressful life events during their current incarceration, the most common being relocation to another cell and being made fun of/insulted by someone in the prison. There were few gender differences in types of events experienced. Regression analyses showed that stressful life events were associated with more loneliness, as well as suicidality, but only when participants had low perceived social support. Conclusions: Stressful life events, and drawing on social support networks to cope with stress, should be addressed in the context of correctional treatments to reduce suicide risk during incarceration
Fragility of the spin-glass-like collective state to a magnetic field in an interacting Fe-C nanoparticle system
The effect of applied magnetic fields on the collective nonequilibrium
dynamics of a strongly interacting Fe-C nanoparticle system has been
investigated. It is experimentally shown that the magnetic aging diminishes to
finally disappear for fields of moderate strength. The field needed to remove
the observable aging behavior increases with decreasing temperature. The same
qualitative behavior is observed in an amorphous metallic spin glass
(Fe_{0.15}Ni_{0.85})_{75}P_{16}B_6Al_3.Comment: 5 pages, 3 figure
Winter Grazing in a Grass-Fed System: Effect of Stocking Density and Sequential Use of Autumn-Stockpiled Grassland on Performance of Yearling Steers
Winter grazing can help reduce the need for purchased feeds in livestock production systems, when finishing cattle on pasture. Our objective was to evaluate the influence of stocking density and grazing stockpiled forage on performance of yearling steers during winter. Three grasslands were winter grazed for two years: I, naturalized pastureland, and II and III, sown and managed for hay production during the growing season but grazed in winter. Two stocking densities were used: low 7.41 and high 12.35 steers ha−1. Herbage mass was estimated before and after each grazing event, and disappearance (consumption, weathering, and trampling) was the difference between both. Forage mass and residual differed by stocking density (SD), year (YR), and grazing interval (GI), and disappearance differed by YR and GI. Grass and dead constituents of botanical composition differed by YR and GI. No differences were found for legumes and forbs. CP differed by YR and GI, and NDF and ADF differed only by YR. Steer average daily gain was 0.15 kg d−1 in 2011 and 0.68 kg d−1 in 2012 and varied by YR and GI. Acceptable gains in 2012 may be a product of environmental conditions that influenced herbage mass and nutritive value during stockpile and animal behavior during winter
Comparison of Two Low-Input Cow/Calf Production Systems on Temperate Grassland
Two systems of grass farming were compared in an eight-year experiment in West Virginia, USA. The grassland consisted primarily of cocksfoot (Dactylis glomerara L.), Kentucky bluegrass (Poa pratensis L.), tall fescue (Festuca arundinacea Schreb.), and red (Trifolium pretense L.) and white clover (T. repens L.). The objective was to compare two systems of beef cow calf production. The experiment was a randomized complete block with two replicated treatments. The grassland of treatment 1 (system 1) was overseeded with legumes, grazing started 1 wk earlier and continued 1 wk later than treatment 2 (system 2) and calves were allowed to forward creep graze. The hay land of treatment 2 received 56 kg N ha-1, at the start of the growing season. Response was measured as calf weaning weight, hay production, and pre-grazing herbage accumulation. Each treatment/replicate (experimental unit) was assigned 6.5 ha divided into three grassland managements units: pasture, buffer and meadow. Pasture was grazed and not cut for hay. First growth of buffer and meadow was harvested as hay. Subsequently, buffer was grazed, meadow was again harvested, followed by late season grazing. Management units were divided into four paddocks. Animals occupied a paddock for 7 days resulting in 4-week grazing cycles from May to mid-November. Eight cow/calf pairs grazed each treatment/replicate (stocking rate 1.23 cow calves ha-1 ). Calves, born in March, were weaned in late September. System 1 calves gained 1.18 kg dy-1 (P \u3c 0.04 SE=0.01) compared with those on System 2 which gained 1.14 kg dy-1. Annual hay production on System 2 was 5784 kg ha-1, significantly more than on System 1 (P \u3c 0.01 SE=107). However, in System 1 extending the grazing season reduced the amount of hay required annually by 1680 kg ha-1. System 1 hay had a greater proportion of legume (9 vs. 3%, P \u3c 0.01 SE=0.5) and a lesser proportion of grass (75 vs. 85%, P \u3c 0.01 SE=0.7) than those of system 2
The High Resolution X-ray Spectrum of SS 433 using the Chandra HETGS
We present observations of SS 433 using the Chandra High Energy Transmission
Grating Spectrometer. Many emission lines of highly ionized elements are
detected with the relativistic blue and red Doppler shifts. The lines are
measurably broadened to 1700 km/s (FWHM) and the widths do not depend
significantly on the characteristic emission temperature, suggesting that the
emission occurs in a freely expanding region of constant collimation with
opening angle of 1.23 +/- 0.06 deg. The blue shifts of lines from low
temperature gas are the same as those of high temperature gas within our
uncertainties, again indicating that the hottest gas we observe to emit
emission lines is already at terminal velocity. Fits to the emission line
fluxes give a range of temperatures in the jet from 5e6 to 1e8 K. We derive the
emission measure as a function of temperature for a four component model that
fits the line flux data. Using the density sensitive Si XIII triplet, the
characteristic electron density is 1e14 cm^{-3}, where the gas temperature is
about 1.3e7 K. Based on an adiabatic expansion model of the jet, the electron
densities drop from ~2e15 to 4e13 cm^{-3} at distances of 2e10 to 2e11 cm from
the apex of the jet cone. The jet mass outflow rate is 1.5e-7 Msun / yr. The
kinetic power is 3.2e38 erg/s, which is x1000 larger than the unabsorbed 2-10
keV X-ray luminosity. The bremsstrahlung emission associated with the lines can
account for the entire continuum; we see no direct evidence for an accretion
disk. The image from zeroth order shows extended emission at a scale of ~2",
aligned in the general direction of the radio jets.Comment: 28 pages, 12 figures (1, 4, 5, and 6 are color), to appear in the
Astrophysical Journa
Brain Computer Interfaces for inclusion
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