Questioning a 3.5 keV dark matter emission line

Context. Recent findings of line emission at 3.5 keV in both individual and stacked X-ray spectra of galaxy clusters have been speculated to have dark matter origin. Aims. If the origin is indeed dark matter, the emission line is expected to be detectable from the Milky Way dark matter halo. Methods. We perform a line search in public Chandra X-ray observations of the region near Sgr A*. We derive upper limits on the line emission flux for the 2.0-9.0 keV energy interval and discuss their potential physical interpretations including various scenarios of decaying and annihilating dark matter. Results. While find no clear evidence for its presence, the upper flux limits are not inconsistent with the recent detections for conservative mass profiles of the Milky Way. Conclusions. The results depends mildly on the spectral modelling and strongly on the choice of dark matter profile.Comment: 10 pages, 7 figures, matches version accepted by A&

Space station experiment definition: Long term cryogenic fluid storage

A preliminary design of an experiment to demonstrate and evaluate long-term cryogenic fluid storage and transfer technologies has been performed. This Long-Term Cryogenic Fluid Storage (LTCFS) experiment is a Technology Development Mission (TDM) experiment proposed by the NASA Lewis Research Center to be deployed on the Initial Operational Capability (IOC) space station. Technologies required by future orbital cryogenic systems such as Orbital Transfer Vehicles (OTV's) were defined, and critical technologies requiring demonstration were chosen to be included in the experiment. A three-phase test program was defined to test the following types of technologies: (1) Passive Thermal Technologies; (2) Fluid Transfer Technologies; and (3) Active Refrigeration Technologies. The development status of advanced technologies required for the LTCFS experiment is summarized, including current, past and future programs

Fostering Critical Thinking about Climate Change: Applying Community Psychology to an Environmental Education Project with Youth

This article argues for the participation of community psychology in issues of global climate change. The knowledge accumulated and experience gained in the discipline of community psychology have great relevance to many topics related to the environment. Practitioners of community psychology could therefore make significant contributions to climate change mitigation. To illustrate this assertion, we describe an education project conducted with youth engaged in a community-based environmental organization. This initiative was motivated by the idea that engaged and critically aware youth often become change agents for social movements. Towards this purpose, rather than using mass marketing strategies to motivate small behavior changes, this project focused intensively on a few youth with the vision that these youth would also influence those around them to rethink their environmental habits. This project was influenced by five community psychology concepts: stakeholder participation, ecological and systems thinking, social justice, praxis, and empirical grounding. In this article we discuss the influence of these concepts on the project’s outcomes, as measured through an evaluative study conducted to assess the impacts of the project on the participating youth in terms of their thinking and action. The contributions of community psychology were found to have greatly impacted the quality of the project and the outcomes experienced by the youth