Augustana College (Illinois)

About: Augustana College (Illinois) is a education organization based out in Rock Island, Illinois, United States. It is known for research contribution in the topics: Higher education & Population. The organization has 491 authors who have published 763 publications receiving 14274 citations. The organization is also known as: Augustana College and Theological Seminary.

Search for Unbound Be-15 States in the 3n+Be-12 Channel

Abstract: Background: $^{15}\mathrm{Be}$ is expected to have low-lying $3/{2}^{+}$ and $5/{2}^{+}$ states. A first search did not find the $3/{2}^{+}$ [A. Spyrou et al., Phys. Rev. C 84, 044309 (2011)]; however, a resonance in $^{15}\mathrm{Be}$ was populated in a second attempt and determined to be unbound with respect to $^{14}\mathrm{Be}$ by 1.8(1) MeV with a tentative spin-parity assignment of $5/{2}^{+}$ [J. Snyder et al., Phys. Rev. C 88, 031303(R) (2013)].Purpose: Search for the predicted ${}^{15}\mathrm{Be}\phantom{\rule{0.16em}{0ex}}3/{2}^{+}$ state in the three-neutron decay channel.Method: A two-proton removal reaction from a 55 MeV/u ${}^{17}\mathrm{C}$ beam was used to populate neutron-unbound states in $^{15}\mathrm{Be}$. The two-, three-, and four-body decay energies of the ${}^{12}\mathrm{Be}\phantom{\rule{0.16em}{0ex}}+$ neutron(s) detected in coincidence were reconstructed using invariant mass spectroscopy. Monte Carlo simulations were performed to extract the resonance and decay properties from the observed spectra.Results: The low-energy regions of the decay energy spectra can be described with the first excited unbound state of $^{14}\mathrm{Be}$ (${E}_{x}=1.54$ MeV, ${E}_{r}=0.28$ MeV). Including a state in $^{15}\mathrm{Be}$ that decays through the first excited $^{14}\mathrm{Be}$ state slightly improves the fit at higher energies though the cross section is small.Conclusions: A $^{15}\mathrm{Be}$ component is not needed to describe the data. If the $3/{2}^{+}$ state in $^{15}\mathrm{Be}$ is populated, the decay by three-neutron emission through $^{14}\mathrm{Be}$ is weak, $\ensuremath{\le}11%$ up to 4 MeV. In the best fit, $^{15}\mathrm{Be}$ is unbound with respect to $^{12}\mathrm{Be}$ by 1.4 MeV (unbound with respect to $^{14}\mathrm{Be}$ by 2.66 MeV) with a strength of $7%$.

Geochronology of the southern margin of the Bighorn Batholith, Wyoming

Abstract: The Bighorn Mountains in north-central Wyoming reveal one of the largest exposures of 2800 Ma to 3000 Ma rocks in Laurentia. The northern part of the crystalline core is composed of the composite Bighorn batholith, whereas the central and southern areas of the range expose older gneiss complexes as well as minor supracrustal rocks. We provide new high-resolution LA-ICPMS U-Pb data on zircons sampled from eleven samples of tonalite, granodiorite, mylonite, and migmatite from the southern margin of the Bighorn batholith in the headwaters of the north fork of Paint Rock Creek. These rocks range from strongly foliated to massive and are difficult to subdivide into mappable units in the field because of their lithologic and structural similarities. Several cross-cutting mylonite zones ( 3000 Ma, ranging to 3500 Ma, which indicates assimilation of older crust. Each of the three age populations reported here are older than the previously reported age of ∼2850 Ma age for the northern Bighorn Batholith but within the 2890 Ma, 2940 Ma, and 2950 Ma age groupings previously reported for the southern gneiss terrane. Three conclusions can be drawn from these data. First, the Bighorn batholith, at least along the southern margin, contains phases at least 80 million years older than the northern phase of the body, and emplacement was protracted and occurred over a ∼100 Ma period. Second, episodes of both intrusion and shearing took place in this area as the various phases of the Bighorn batholith were emplaced. Finally, the existence of inherited zircons within the Bighorn batholith in the age range of ∼3.0 Ga to 3.5 Ga indicates that the Bighorn batholith intruded through older crust. This older crust is perhaps a northern extension of Sacawee block in the northern Granite Mountains of central Wyoming, which may underlie the Bighorn Mountains.

Testing a risky sex behavior intervention pilot website for adolescents

Abstract: BACKGROUND AND PURPOSE: Each year, teenagers account for about one-fifth of all unintended pregnancies in the United States. As such, delivering sexual risk reduction educational materials to teens in a timely fashion is of critical importance. Web-based delivery of these materials shows promise for reaching and persuading teens away from risky sexual and substance abuse behaviors. The purpose of this study was to pilot test a web-based program aimed at reducing risky sexual behavior and related outcomes among adolescents in a high school setting. METHODS: A beta-test of the website was conducted in three public schools in New Mexico, USA with 173 students in 9(th) and 10(th) grades recruited from existing health education classes. Participants spent approximately three hours over a period of two days completing the online program in school computer labs. RESULTS: Pretest to posttest results indicated that self-efficacy for condom use and condom use intentions, two theoretical mediators of changes in condom use behavior, were significantly changed. Adolescents also reported high satisfaction with the website content. CONCLUSION: BReady4it provided an innovative sex and substance abuse education to teenagers that revealed promising positive changes in cognitive constructs that are inversely related to risky sexual behavior among users. Language: en

Population of Be 13 in a nucleon exchange reaction

Abstract: The neutron-unbound nucleus $^{13}\mathrm{Be}$ was populated with a nucleon exchange reaction from a 71 MeV/u secondary $^{13}\mathrm{B}$ beam. The decay-energy spectrum was reconstructed using invariant mass spectroscopy based on $^{12}\mathrm{Be}$ fragments in coincidence with neutrons. The data could be described with an $s$-wave resonance at ${E}_{r}=0.73(9)\phantom{\rule{4.pt}{0ex}}\mathrm{MeV}$ with a width of ${\mathrm{\ensuremath{\Gamma}}}_{r}=1.98(34)\phantom{\rule{4.pt}{0ex}}\mathrm{MeV}$ and a $d$-wave resonance at ${E}_{r}=2.56(13)\phantom{\rule{4.pt}{0ex}}\mathrm{MeV}$ with a width of ${\mathrm{\ensuremath{\Gamma}}}_{r}=2.29(73)\phantom{\rule{4.pt}{0ex}}\mathrm{MeV}$. The observed spectral shape is consistent with previous one-proton removal reaction measurements from $^{14}\mathrm{B}$.