An Existential Ethical Imperative

The author’s purpose in this article is to show that Sartre’s ontological structure has room in it for an existential imperative that makes moral activity possible. The author dramatically reveals that “we cannot will freedom without grasping, on an interhuman level, the ambiguous existence of each other.” This reality results from an understanding of Sartre’s notions of consciousness, temporality, bad faith, authenticity, freedom, responsibility, and especially the Other. By the end of his exegesis, the author has shown that Sartre’s phenomenology requires each of us to be authentic as being-for-itself and as being-for-others. The author uses this conclusion to negate Dostoevsky’s famous worry about everything being permissible, because we can definitely say that accepting one’s wish to become a slave is not compatible with authenticity

Evidence for coeval Late Triassic terrestrial impacts from the Rochechouart (France) meteorite crater

High temperature impact melt breccias from the Rochechouart (France) meteorite crater record magnetization component with antipodal, normal and reverse polarities. The corresponding paleomagnetic pole for this component lies between the 220 Ma and 210 Ma reference poles on the Eurasian apparent polar wander path, consistent with the 214 $\pm$ 8 Ma 40Ar/39Ar age of the crater. Late Triassic tectonic reconstructions of the Eurasian and North American plates place this pole within 95% confidence limits of the paleomagnetic pole from the Manicouagan (Canada) meteorite impact crater, which is dated at 214 $\pm$ 1 Ma. Together, these observations reinforce the hypothesis of a Late Triassic, multiple meteorite impact event on Earth

Asymmetric switching behavior in perpendicularly magnetized spin-valve nanopillars due to the polarizer dipole field

We report the free layer switching field distributions of spin-valve nanopillars with perpendicular magnetization. While the distributions are consistent with a thermal activation model, they show a strong asymmetry between the parallel to antiparallel and the reverse transition, with energy barriers more than 50% higher for the parallel to antiparallel transitions. The inhomogeneous dipolar field from the polarizer is demonstrated to be at the origin of this symmetry breaking. Interestingly, the symmetry is restored for devices with a lithographically defined notch pair removed from the midpoint of the pillar cross-section along the ellipse long axis. These results have important implications for the thermal stability of perpendicular magnetized MRAM bit cells.Comment: Submitted to Applied Physics Letters on November 4, 2011. Consists of 4 pages, 3 figure

ProtoDESI: First On-Sky Technology Demonstration for the Dark Energy Spectroscopic Instrument

The Dark Energy Spectroscopic Instrument (DESI) is under construction to measure the expansion history of the universe using the baryon acoustic oscillations technique. The spectra of 35 million galaxies and quasars over 14,000 square degrees will be measured during a 5-year survey. A new prime focus corrector for the Mayall telescope at Kitt Peak National Observatory will deliver light to 5,000 individually targeted fiber-fed robotic positioners. The fibers in turn feed ten broadband multi-object spectrographs. We describe the ProtoDESI experiment, that was installed and commissioned on the 4-m Mayall telescope from August 14 to September 30, 2016. ProtoDESI was an on-sky technology demonstration with the goal to reduce technical risks associated with aligning optical fibers with targets using robotic fiber positioners and maintaining the stability required to operate DESI. The ProtoDESI prime focus instrument, consisting of three fiber positioners, illuminated fiducials, and a guide camera, was installed behind the existing Mosaic corrector on the Mayall telescope. A Fiber View Camera was mounted in the Cassegrain cage of the telescope and provided feedback metrology for positioning the fibers. ProtoDESI also provided a platform for early integration of hardware with the DESI Instrument Control System that controls the subsystems, provides communication with the Telescope Control System, and collects instrument telemetry data. Lacking a spectrograph, ProtoDESI monitored the output of the fibers using a Fiber Photometry Camera mounted on the prime focus instrument. ProtoDESI was successful in acquiring targets with the robotically positioned fibers and demonstrated that the DESI guiding requirements can be met.Comment: Accepted versio

International perspectives on the future of geography education: an analysis of national curricula and standards

Geography as a school subject is expressed in a wide variety of ways across different national jurisdictions. This article explores some of the issues arising from attempts to represent geography as a subject for study in schools through the organisational structures offered by national standards and/or national curricula. It serves as an introduction to this special issue, which primarily concerns itself with the contemporary analysis of geography education in seven national settings across the globe. We stress the importance of considering political, cultural, social and philosophical traditions when analysing the curriculum choices made for geography education. Although it may be assumed that geography as a disciplinary specialism is concerned with a body of knowledge that is common across the globe, the creative tensions generated between the disciplines, educational trends and matters of social or policy concern play out differently, making comparisons across jurisdictions hazardous. Understanding this, we argue, is of great significance to those who plan and shape the geography curriculum. Despite the difficulties we hope to offer something more useful than a series of descriptions of geography teaching in different national settings. The purpose of this paper is to introduce a set of robust and irresistible arguments for the inclusion of the study of geography in schools. We argue that geographical knowledge is a vital component of the education of young people across the globe, even though it may be expressed in different ways in different national settings