The teacher’s role for engagement in foraging and gardening activities in kindergarten

Early childhood education provides an important arena for fostering valuable habits and practices for sustainability. This paper contributes to understanding the educator’s role within early childhood environmental education in foraging and gardening practices. What pedagogical approaches does the teacher provide to foster the children’s participation, engagement, and learning in such activities? To investigate this question, we used a qualitative approach, including video and on-site interviews with kindergarten teachers during foraging or gardening activities. We also analyzed semi-structural interviews and collected field notes for in-depth views and reflections from the teachers. The qualitative data were analyzed using reflective thematic analysis. The data analysis suggests three themes that exemplify hallmarks of the teacher’s role: (1) facilitating adventurous experience, (2) child-centered communication, and (3) building collective knowledge and skills. The implications for the future are discussed with respect to the kindergarten teacher’s pivotal function in supporting children as eco-citizens for sustainability. The data show that the kindergarten teachers’ over-arching role is to take leadership of fostering engagement and learning for everyone involved

Runaway electron generation during tokamak start-up

Tokamak start-up is characterized by low electron densities and strong electric fields, in order to quickly raise the plasma current and temperature, allowing the plasma to fully ionize and magnetic flux surfaces to form. Such conditions are ideal for the formation of superthermal electrons, which may reduce the efficiency of ohmic heating and prevent the formation of a healthy thermal fusion plasma. This is of particular concern in ITER where engineering limitations put restrictions on the allowable electric fields and limit the prefill densities during start-up. In this study, we present a new 0D burn-through simulation tool called STREAM (STart-up Runaway Electron Analysis Model), which self-consistently evolves the plasma density, temperature and electric field, while accounting for the generation and loss of relativistic runaway electrons. After verifying the burn-through model, we investigate conditions under which runaway electrons can form during tokamak start-up as well as their effects on the plasma initiation. We find that Dreicer generation plays a crucial role in determining whether a discharge becomes runaway-dominated or not, and that a large number of runaway electrons could limit the ohmic heating of the plasma, thus preventing successful burn-through or further ramp-up of the plasma current. The runaway generation can be suppressed by raising the density via gas fuelling, but only if done sufficiently early. Otherwise a large runaway seed may have already been built up, which can avalanche even at relatively low electric fields and high densities

No-horizon theorem for vacuum gravity with spacelike G1 isometry groups

We show that (3+1) vacuum spacetimes admitting a global, spacelike, one-parameter Lie group of isometries of translational type cannot contain apparent horizons. The only assumption made is that of the existence of a global spacelike Killing vector field with infinite open orbits; the four-dimensional vacuum spacetime metric is otherwise arbitrary. This result may thus be viewed as a hoop conjecture theorem for vacuum gravity with one spacelike translational Killing symmetry.Comment: 6 pages, revtex4; published in Phys. Rev. D Rapid Com

Dynamics of Brane-World Cosmological Models

We show that generically the initial singularity is isotropic in spatially homogeneous cosmological models in the brane-world scenario. We then argue that it is plausible that the initial singularity is isotropic in typical brane world cosmological models. Therefore, brane cosmology naturally gives rise to a set of initial data that provide the conditions for inflation to subsequently take place, thereby solving the initial conditions problem and leading to a self--consistent and viable cosmology.Comment: Final version. To appear in Physical Revie

No-horizon theorem for spacetimes with spacelike G1 isometry groups

We consider four-dimensional spacetimes $(M,{\mathbf g})$ which obey the Einstein equations ${\mathbf G}={\mathbf T}$, and admit a global spacelike $G_{1}={\mathbb R}$ isometry group. By means of dimensional reduction and local analyis on the reduced (2+1) spacetime, we obtain a sufficient condition on ${\mathbf T}$ which guarantees that $(M,{\mathbf g})$ cannot contain apparent horizons. Given any (3+1) spacetime with spacelike translational isometry, the no-horizon condition can be readily tested without the need for dimensional reduction. This provides thus a useful and encompassing apparent horizon test for $G_{1}$-symmetric spacetimes. We argue that this adds further evidence towards the validity of the hoop conjecture, and signals possible violations of strong cosmic censorship.Comment: 8 pages, LaTeX, uses IOP package; published in Class. Quantum Gra

Challenges, Strategies, and Impacts of Doing Citizen Science with Marginalised and Indigenous Communities : Reflections from Project Coordinators

Citizen science is growing and increasingly realizing its potential in terms of benefiting science and society. However, there are significant barriers to engaging participants in non-Western, non-educated, non-industrialised, non-rich and non-democratic contexts. By reflecting on the experiences of 15 citizen science project coordinators, this paper contributes to the small but growing body of knowledge attempting to identify barriers and opportunities of doing citizen science with marginalised and Indigenous communities. Challenges affecting participation in the analysed projects include issues that range from lack of basic infrastructure and participant safety to unbalanced knowledge hierarchies and data rights. We found that, to overcome these challenges, projects have used several strategies, from promoting decentralized and low-tech solutions to engaging in bottom-up actions from a human-rights approach. Finally, our analysis of project impacts supports the idea that doing citizen science with marginalised and Indigenous communities might have a greater impact for participants than for science, as scientific achievements (although valuable) were not among the most important impacts highlighted in terms of project success. By providing stories from the field in a structured way, we aim to guide, to inform, and to inspire other citizen science projects, and to, ultimately, contribute to broader participation in citizen science in the future

Challenges, Strategies, and Impacts of Doing Citizen Science with Marginalised and Indigenous Communities: Reflections from Project Coordinators

Citizen science is growing and increasingly realizing its potential in terms of benefiting science and society. However, there are significant barriers to engaging participants in non-Western, non-educated, non-industrialised, non-rich and non-democratic contexts. By reflecting on the experiences of 15 citizen science project coordinators, this paper contributes to the small but growing body of knowledge attempting to identify barriers and opportunities of doing citizen science with marginalised and Indigenous communities. Challenges affecting participation in the analysed projects include issues that range from lack of basic infrastructure and participant safety to unbalanced knowledge hierarchies and data rights. We found that, to overcome these challenges, projects have used several strategies, from promoting decentralized and low-tech solutions to engaging in bottom-up actions from a human-rights approach. Finally, our analysis of project impacts supports the idea that doing citizen science with marginalised and Indigenous communities might have a greater impact for participants than for science, as scientific achievements (although valuable) were not among the most important impacts highlighted in terms of project success. By providing stories from the field in a structured way, we aim to guide, to inform, and to inspire other citizen science projects, and to, ultimately, contribute to broader participation in citizen science in the futur

Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers

We present a review of the interplay between the evolution of circumstellar disks and the formation of planets, both from the perspective of theoretical models and dedicated observations. Based on this, we identify and discuss fundamental questions concerning the formation and evolution of circumstellar disks and planets which can be addressed in the near future with optical and infrared long-baseline interferometers. Furthermore, the importance of complementary observations with long-baseline (sub)millimeter interferometers and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics Review"; The final publication is available at http://www.springerlink.co

Habitable Zones in the Universe

Habitability varies dramatically with location and time in the universe. This was recognized centuries ago, but it was only in the last few decades that astronomers began to systematize the study of habitability. The introduction of the concept of the habitable zone was key to progress in this area. The habitable zone concept was first applied to the space around a star, now called the Circumstellar Habitable Zone. Recently, other, vastly broader, habitable zones have been proposed. We review the historical development of the concept of habitable zones and the present state of the research. We also suggest ways to make progress on each of the habitable zones and to unify them into a single concept encompassing the entire universe.Comment: 71 pages, 3 figures, 1 table; to be published in Origins of Life and Evolution of Biospheres; table slightly revise