5,690 research outputs found
Triton's surface age and impactor population revisited in light of Kuiper Belt fluxes: Evidence for small Kuiper Belt objects and recent geological activity
Neptune's largest satellite, Triton, is one of the most fascinating and
enigmatic bodies in the solar system. Among its numerous interesting traits,
Triton appears to have far fewer craters than would be expected if its surface
was primordial. Here we combine the best available crater count data for Triton
with improved estimates of impact rates by including the Kuiper Belt as a
source of impactors. We find that the population of impactors creating the
smallest observed craters on Triton must be sub-km in scale, and that this
small-impactor population can be best fit by a differential power-law size
index near -3. Such results provide interesting, indirect probes of the unseen
small body population of the Kuiper Belt. Based on the modern, Kuiper Belt and
Oort Cloud impactor flux estimates, we also recalculate estimated ages for
several regions of Triton's surface imaged by Voyager 2, and find that Triton
was probably active on a time scale no greater than 0.1-0.3 Gyr ago (indicating
Triton was still active after some 90% to 98% of the age of the solar system),
and perhaps even more recently. The time-averaged volumetric resurfacing rate
on Triton implied by these results, 0.01 km yr or more, is likely
second only to Io and Europa in the outer solar system, and is within an order
of magnitude of estimates for Venus and for the Earth's intraplate zones. This
finding indicates that Triton likely remains a highly geologically active world
at present, some 4.5 Gyr after its formation. We briefly speculate on how such
a situation might obtain.Comment: 14 pages (TeX), plus 2 postscript figures Stern & McKinnon, 2000, AJ,
in pres
External liquid-spray cooling of turbine blades Patent
External device for liquid spray cooling of gas turbine blade
Alien Registration- Mckinnon, Edward J. (Auburn, Androscoggin County)
https://digitalmaine.com/alien_docs/31112/thumbnail.jp
The road to same-sex marriage support has been long - and the fight isn\u27t over yet
Today\u27s same-sex marriage survey results represent a moment of extraordinary change. It is well within living memory that homosexuality in Australia was considered a crime, a sickness and a threat to the nation itself. The final Australian state to decriminalise male homosexuality was Tasmania, as recently as 1997. Plenty of gay men still remember the fear of prison terms that shadowed their lives. Plenty of lesbians still remember that, although their sex lives were never criminalised, the police and the courts found ways to oppress and harass them nonetheless. Many LGBTIQ people still carry the emotional and physical scars of brutal medical interventions designed to fix something that was never broken. And yet, from the birth of the Australian lesbian and gay rights movement at the end of the 1960s, through the growing inclusivity of LGBTIQ activist politics in the decades since, we have somehow reached a point in November 2017 where millions of heterosexual Australians have chosen to tick a box saying yes . In the process, they have helped a once demonised, pathologised and criminalised minority take a major step towards equality
Why are we still scared of seeing two men kissing?
Although details remain uncertain, the father of Omar Mateen has claimed that his son\u27s murderous acts in Orlando\u27s Pulse nightclub last Saturday may have been inspired by the sight of two men kissing. In response, a twitter campaign with the hashtag #TwoMenKissing has encouraged men to tweet photographs of themselves kissing another man. This is an act of pride and defiance in the face of violent oppression. It also reveals the ongoing politics of men kissing in public
With Moonlight\u27s Oscar win, Hollywood begins to right old wrongs
When Faye Dunaway, standing next to a puzzled-looking Warren Beatty, announced that La La Land had won Best Picture at Monday\u27s Oscars, I doubt many people were surprised. Sure, pretty much all of the queer film fans, writers and academics I follow on Twitter were hoping for a win by the new gay classic Moonlight, but we are a crowd that has been disappointed before
Academic Optimism of Schools and Student Achievement
The pressure to perform well on high stakes testing may have caused many educational leaders to shift their focus away from developing a healthy organization that may enhance and possibly even predict student achievement to simply focusing on test scores. Hoy, Tarter and Hoy (2006) suggested that high levels of Academic OptimismAO (including collective teacher efficacy-CTE, faculty trust in parents and students-FT, and academic emphasis-AE), when controlling for SES, is a strong force in predicting academic achievement. This study attempted to support previous research findings and to provide educational administrators with a framework for improving school organizational health for the purpose of enhancing student achievement.
This study examined the relationships between AO, its sub-constructs, and student achievement in reading and math, when controlling for SES, for four participating middle schools located in two school districts in southeast Georgia. The data was collected from the School Academic Optimism Survey (SAOS) which is designed to measure the overall level of academic optimism within the school and each of the sub-constructs. The SAOS provides 30 Likert-type items with 1-12 measuring CTE, 13-22 measuring FT and 23-30 measuring AE. Overall, the analysis of the relationship of AO of schools and achievement in reading and math, when controlling for SES, is not statistically significant in this study. The variance in reading and math achievement showed 0% change in the relationship when adding AO as a predictor. Although some improvement in relationships, particularly in reading, was noted when adding the predictor variables of CTE, FT, and AE, the results suggested these variables did not predict student achievement over SES.
All schools in this study reported at least average levels of AO, all four schools were achieving in reading above the state percentage, and 3 of the 4 were achieving above the state percentage in math. Additionally, 3 of the 4 schools had populations of economically disadvantaged students above the state average. Although further research with a larger sample size is recommended, this may suggest that schools with low SES students are not necessarily at a disadvantage when variables associated with school organizational health are considered
Alien Registration- Mckinnon, Urban J. (Portland, Cumberland County)
https://digitalmaine.com/alien_docs/21535/thumbnail.jp
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