5 resultados para UV CETI STARS
em Bucknell University Digital Commons - Pensilvania - USA
Resumo:
Background: UV exposure causes a wide range of skin damage including cutaneous melanoma. The mechanisms of cellular and molecular damage as well as erythemal and pigmentation responses to UV exposure have largely been studied in the White population. Methods: This study systematically investigates responses to UV exposure in the Native Hawaiian and Pacific Islanders (NHPI) and Asian populations living in Hawai’i (A/HI) as well as in Asians living in Maryland (A/MD). Results: Our analyses indicate that the NHPI population is less sensitive to UV exposure than the A/HI population. Comparisons between the two Asian groups suggest that, despite slightly but not statistically different baseline constitutive pigmentation (pre-UV exposure), the A/HI and A/MD had similar UV sensitivity, measured as minimal erythemal dose (MED). However, the A/MD population had higher levels of oxy-hemoglobin at doses of 2.0, 2.8 and 4.0 MED. Unexpectedly the A/MD subjects retained higher levels of pigmentation 2 weeks post UV exposure. Conclusion: This study provides insight into UV responses of the inhabitants of Hawai’i and shows that such responses are statistically significant for relatively small samples of Native Hawaiian and Pacific Islanders, and for Asians living in Hawai’i and Asians living in Maryland.
Resumo:
The current case study examined the effects of the STARS-PAC anxiety reduction program on the social and test anxiety levels of a middle school student. The literature supporting the effectiveness of cognitive behavioral therapy programs which incorporate methods such as those used in the STARS-PAC program were reviewed. The findings of this case study indicated decreased levels of overall anxiety during the intervention phase; however, the student’s test anxiety level displayed little improvement. Implications of the findings and for future research are discussed.
Resumo:
We report the selection and spectroscopic confirmation of 129 new late-type (SpT = K3-M6) members of the Tucana-Horologium moving group, a nearby (d similar to 40 pc), young (tau similar to 40 Myr) population of comoving stars. We also report observations for 13 of the 17 known Tuc-Hor members in this spectral type range, and that 62 additional candidates are likely to be unassociated field stars; the confirmation frequency for new candidates is therefore 129/191 = 67%. We have used radial velocities, Ha emission, and Li-6708 absorption to distinguish between contaminants and bona fide members. Our expanded census of Tuc-Hor increases the known population by a factor of similar to 3 in total and by a factor of similar to 8 for members with SpT >= K3, but even so, the K-M dwarf population of Tuc-Hor is still markedly incomplete. Our expanded census allows for a much more detailed study of Tuc-Hor than was previously feasible. The spatial distribution of members appears to trace a two-dimensional sheet, with a broad distribution in X and Y, but a very narrow distribution (+/- 5 pc) in Z. The corresponding velocity distribution is very small, with a scatter of +/- 1.1 km s(-1) about the mean UVW velocity for stars spanning the entire 50 pc extent of Tuc-Hor. We also show that the isochronal age (tau similar to 20-30 Myr) and the lithium depletion boundary age (tau similar to 40 Myr) disagree, following the trend in other pre-main-sequence populations for isochrones to yield systematically younger ages. The H alpha emission line strength follows a trend of increasing equivalent width with later spectral type, as is seen for young clusters. We find that moving group members have been depleted of measurable lithium for spectral types of K7.0-M4.5. None of our targets have significant infrared excesses in the WISE W3 band, yielding an upper limit on warm debris disks of F < 0.7%. Finally, our purely kinematic and color-magnitude selection procedure allows us to test the efficiency and completeness for activity-based selection of young stars. We find that 60% of K-M dwarfs in Tuc-Hor do not have ROSAT counterparts and would have been omitted in X-ray-selected samples. In contrast, GALEX UV-selected samples using a previously suggested criterion for youth achieve completeness of 77% and purity of 78%, and we suggest new SpT-dependent selection criteria that will yield > 95% completeness for tau similar to 40 Myr populations with GALEX data available.