Educational Poster: Service Dogs

The foundation of instructional design and e-learning incorporates the distribution of digital media elements such as educational posters. An educational poster includes research into the topic, problem-solving, decision making, communication of information, locating resources, work with a digital camera, and utilization of powerful software such as Adobe Photoshop; all the while following the foundation principles of PARC. PARC stands for proximity, alignment, repetition, and contrast. Proximity indicates that objects are grouped together suggesting a close relationship with one another and can create a sense of balance, harmony, or even discord. Alignment gives organization and meaning to the project. Repetition unites the poster to a comprehensive whole and provides a rhythm for the presentation. Contrast that helps the observer focus attention on the subject while creating visual interest, excitement, and drama

Evolutionary and Physical Properties of Meteoroids

Astrophysical models for meteoroid formation and stellar and planetary evolutions are developed from simulation composition studies

The Survival of Microorganisms in Space. Further Rocket and Balloon Borne Exposure Experiments

Rocket and balloon borne exposure experiments on survival of microorganisms in space environmen

Image-orthicon spectra of Geminids in 1969

The spectra of 25 meteors, recorded with an image orthicon technique in December 1969, are studied in relation to similar records made in August of the same year. Of 19 Geminid meteors in the absolute visual magnitude range 0 to +2, only one showed any evidence of the forbidden line of oxygen at 5577 A, while all Perseid meteors recorded in August exhibited the oxygen line, a result of the large difference in geocentric velocity between the two showers. Atoms identified in faint Geminid meteors include neutral iron, magnesium, calcium and sodium. The molecular bands of nitrogen are also observed

Gun Carrying Among Adolescents

Outdoor education is a promising educational field that can support indoor education and provide benefits beyond the evidentknowledge. Outdoor and indoor education together can formulate the ground for an integrated learning. In Greece, like manycountries, outdoor education and its potential contribution to the learning process have not been clearly and intentionally testedyet, even though the country tends to follow a progressive educational philosophy. This research focuses on the subject ofmathematics and explores the connections between the existing philosophy and practices of mathematics education in Greece andoutdoor education theory and practice. Following the method of content analysis, the connections were identified through theexistence of basic outdoor education concepts in the mathematics textbooks of the last three grades of primary school. Althoughthe expectations, because of the lack of personal experiences, could not be high, the application of outdoor education seems to befar from impossible in Greece. It could rather flourish even without any changes in the books, when its potentialities are realizedby the teachers

An unusual meteor spectrum

An extraordinary spectrum of a meteor at a velocity of about 18.5 + or - 1.0 km/s was observed with an image orthicon camera. The radiant of the meteor was at an altitude of about 49 deg. It was first seen showing a yellow red continuous spectrum alone at a height of 137 + or - 8 km which is ascribed to the first positive group of nitrogen bands. After the meteor had descended to 116 + or - 6 km above sea level it brightened rapidly from its previous threshold brightness into a uniform continuum, the D-line of neutral sodium appeared, and at height 105 + or - 5 km all the other lines of the spectrum also appeared. The continuum remained dominant to the end. Water of hydration and entrained carbon flakes of characteristic dimension about 0.2 micron or less are proposed as constituents of the meteoroid to explain these phenomena

Photometry of Proxima Centauri and Barnard's Star Using HST Fine Guidance Sensor 3: A Search for Periodic Variations

We have observed Proxima Centauri and Barnard's Star with Hubble Space Telescope Fine Guidance Sensor 3. Proxima Centauri exhibits small-amplitude, periodic photometric variations. Once several sources of systematic photometric error are corrected, we obtain 2 milli-magnitude internal photometric precision. We identify two distinct behavior modes over the past four years: higher amplitude, longer period; smaller amplitude, shorter period. Within the errors one period (P ~ 83d) is twice the other. Barnard's Star shows very weak evidence for periodicity on a timescale of approximately 130 days. If we interpret these periodic phenomena as rotational modulation of star spots, we identify three discrete spots on Proxima Cen and possibly one spot on Barnard's Star. We find that the disturbances change significantly on time scales as short as one rotation period.Comment: 39 pages, 17 figure

Interferometric Astrometry of Proxima Centauri and Barnard's Star Using Hubble Space Telescope Fine Guidance Sensor 3: Detection Limits for sub-Stellar Companions

We report on a sub-stellar companion search utilizing interferometric fringe-tracking astrometry acquired with Fine Guidance Sensor 3 (FGS 3) on the Hubble Space Telescope. Our targets were Proxima Centauri and Barnard's Star. We obtain absolute parallax values for Proxima Cen pi_{abs} = 0.7687 arcsecond and for Barnard's Star pi_{abs} = 0.5454 arcsecond. Once low-amplitude instrumental systematic errors are identified and removed, our companion detection sensitivity is less than or equal to one Jupiter mass for periods longer than 60 days for Proxima Cen. Between the astrometry and the radial velocity results we exclude all companions with M > 0.8M_{Jup} for the range of periods 1 < P < 1000 days. For Barnard's Star our companion detection sensitivity is less than or equal to one Jupiter mass for periods long er than 150 days. Our null results for Barnard's Star are consistent with those of Gatewood (1995).Comment: 35 pages, 13 figures, to appear in August 1999 A