273 research outputs found

    The Civilian Conservation Corps as a Tool of the National Park Service: The Development of Glacier and Yellowstone National Parks, 1933-1942

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    Throughout its seventy-two year history, the National Park Service has walked a fine line between the two parts of its mission as set forth in the Park Service’s organic act of August 25, 1916. Congress dictated that the Service provide for the enjoyment of the people, yet, at the same time, preserve the nation’s parks unimpaired for future generations. The fledgling Park Service’s officials needed to find ways of bringing more money to the Service to establish a firm base for park system growth. Park Service administrators knew that only by attracting more visitors to the parks could the public interest in the parks develop, which, in turn, would bring increased appropriations for the Service. Throughout the 1920s, Steven Mather and his successor, Horace Albright expanded the Park Service’s interests by including battlefields, historic sites, and recreation areas under the Service’s auspices to provide a greater variety of park experiences for more people. Faced with reduced appropriations in the depths of the Depression, the Park Service concentrated on the ’’use” aspect of its dichotomous mission as a way to increase visitation, and therefore, appropriations. The Park Service welcomed the establishment of the Civilian Conservation Corps (CCC) as a harbinger of increased financial security. The financial resources and the manpower of the CCC enabled the Park Service to develop the nation’s parks for tourist comfort. This study concentrates on Glacier and Yellowstone National Parks as case histories of the National Park Service use of the CCC to develop the nation’s parks. Most of the CCC work projects in Glacier and Yellowstone concentrated on making the parks more comfortable or more attractive for visitors. Reforestation, campground development, the building of roads and trails, fire hazard reduction, and fire fighting were major CCC projects designed to achieve those ends in Glacier and Yellowstone parks. Materials used in this study include primary and secondary sources. The primary sources, including the Glacier and Yellowstone superintendents’ annual and monthly reports, Emergency Conservation Work/CCC directors\u27 reports and numerous ex-CCC enrollee reminiscences proved particularly informative

    Spiral Growth and Step Edge Barriers

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    The growth of spiral mounds containing a screw dislocation is compared to the growth of wedding cakes by two-dimensional nucleation. Using phase field simulations and homoepitaxial growth experiments on the Pt(111) surface we show that both structures attain the same characteristic large scale shape when a significant step edge barrier suppresses interlayer transport. The higher vertical growth rate observed for the spiral mounds on Pt(111) reflects the different incorporation mechanisms for atoms in the top region and can be formally represented by an enhanced apparent step edge barrier.Comment: 11 pages, 4 figures, partly in colo

    Sex Education in Montana Schools: An Assessment of the Needs of Sexual and Gender Minority Youth

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    Youth are particularly vulnerable to infection from HIV and STIs. According to the Centers for Disease Control and Prevention, youth between the ages of 13 and 24 accounted for about 26% of all new HIV transmission cases in the United States in 2010, In young MSM specifically, there was a 22% increase in new infections from 2008 to 2010 (CDC, 2015). Education is one of the factors that plays a role in sexual health practices starting in high schools, yet in Montana there is no clear set of guidelines as to what is covered during sex education classes in the health classroom, especially for topics relating to the sexual and gender minority (LGBTQ+) populations. This study represented one of the first attempts to gather information about the curricula for sexuality education in high schools across the state of Montana. The survey was distributed online via social media sites and through email. Anyone aged 18 to 24 who graduated from high school in Montana was able to participate. Results of this statewide survey revealed that while the majority of respondents perceived all of the topics listed on the survey as very important, many of the topics were only partially covered or not covered at all.. In fact, only 5% of respondents perceived that topics specifically related to LBGTQ+ issues were being fully covered. Fully half of the respondents believed their teachers were uncomfortable teaching sex education and an overwhelming majority believed that their sex education classes were useless. Educators’ apparent discomfort in teaching sex education may contribute to the lack of coverage of many topics and to students’ perceptions that the courses are not helpful. Most importantly, LBGTQ+ respondents reported attempting suicide at more than three times the rate of their heterosexual/cisgender peers when in high school. While not a panacea, it seems reasonable to assume that a sex education curriculum that is comprehensive, inclusive of LGBTQ+ students and taught by teachers who are trained and comfortable talking about the multitude of issues surrounding adolescent sexuality could only enhance the quality of life of students who believe they have no one to whom they can relate and fear others discovering their sexual and/or gender minority status. The Montana Department of Public Health and Human Services and other health care organizations may use this information to create interventions that are tailored to the unique needs of the young sexual and gender minority youth population in Montana

    Chemical ordering and composition fluctuations at the (001) surface of the Fe-Ni Invar alloy

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    We report on a study of (001) oriented fcc Fe-Ni alloy surfaces which combines first-principles calculations and low-temperature STM experiments. Density functional theory calculations show that Fe-Ni alloy surfaces are buckled with the Fe atoms slightly shifted outwards and the Ni atoms inwards. This is consistent with the observation that the atoms in the surface layer can be chemically distinguished in the STM image: brighter spots (corrugation maxima with increased apparent height) indicate iron atoms, darker ones nickel atoms. This chemical contrast reveals a c2x2 chemical order (50% Fe) with frequent Fe-rich defects on Invar alloy surface. The calculations also indicate that subsurface composition fluctuations may additionally modulate the apparent height of the surface atoms. The STM images show that this effect is pronounced compared to the surfaces of other disordered alloys, which suggests that some chemical order and corresponding concentration fluctuations exist also in the subsurface layers of Invar alloy. In addition, detailed electronic structure calculations allow us to identify the nature of a distinct peak below the Fermi level observed in the tunneling spectra. This peak corresponds to a surface resonance band which is particularly pronounced in iron-rich surface regions and provides a second type of chemical contrast with less spatial resolution but one that is essentially independent of the subsurface composition.Comment: 7 pages, 5 figure

    Thoughts of self-harm in early and late pregnancy in urban South Africa: Investigating prevalence, predictors and screening options

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    Background. Thoughts of self-harm (TSH) are an important marker of mental health risk, and risk for attempted and completed suicide. While there is increasing attention being paid to mental health problems in pregnancy in South Africa (SA), TSH have received less attention despite some cross-sectional studies suggesting that prevalence may be high (12 - 39%). There is a dearth of longitudinal research to inform prevention and treatment.Objectives. To examine the rates of TSH across pregnancy in a longitudinal SA cohort and to investigate factors associated with the onset and persistence of TSH, as well as the relationship between TSH, depression and/or anxiety.Methods. Women were enrolled in a prospective pregnancy cohort (S1000) in Soweto, SA between 2014 and 2016, and assessed using validated screening measures (Edinburgh Postnatal Depression Scale (EPDS) and State Trait Anxiety Index short form) in early and later pregnancy. Data were available for 649 women. TSH were determined using EPDS item 10. Logistic regression and bifactor models were used to determine factors associated with TSH across pregnancy.Results. Of the 649 women, 18% reported TSH at some stage during their pregnancy. Prevalence of TSH was slightly higher in early pregnancy (12.5%) than later in pregnancy (11.6%). TSH were associated with a history of mental illness (adjusted odds ratio (aOR) 4.17; 95% confidence interval (CI) 1.3 - 13.7; p=0.020), concurrent depression (aOR 4.8; 95%CI 2.7 - 8.6; p<0.001); marital stress (aOR 1.74; 95% CI 1.0 - 3.0; p=0.040); and practical support (aOR 0.43; 95% CI 0.2 - 1.0; p=0.040) using a multivariate logistic regression. Bifactor analysis examining depression and anxiety scales showed that TSH contributed the highest variance to a shared depression and anxiety factor in early pregnancy. Logistic regressions showed that early depression was a strong predictor of later reports of TSH.Conclusions. The present study shows that the risk of TSH during pregnancy is relatively common, and starts early during pregnancy. Screening approaches could be simplified to encourage healthcare practitioners working in busy and over-burdened public healthcare settings to engage in identifying at-risk women. Efforts in improving early identification of mental health risk in pregnancy should be matched with strengthening of current treatment and referral options. Since practical support and a good marital relationship reduce the risk of TSH, these may be important avenues of focus for designing interventions

    Experimental observation of defect pair separation triggering phase transitions

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    First-order phase transitions typically exhibit a significant hysteresis resulting for instance in boiling retardation and supercooling. The hysteresis arises, because nucleation of the new phase is activated. The free-energy change is positive until the nucleus reaches a critical size beyond which further growth is downhill. In practice, the barrier is often circumvented by the presence of heterogeneous nucleation centres, e. g. at vessel walls or seed crystals. Recently, it has been proposed that the homogeneous melting of ice proceeds via separation of defect pairs with a substantially smaller barrier as compared to the mere aggregation of defects. Here we report the observation of an analogous mechanism catalysing a two-dimensional homogeneous phase transition. A similar process is believed to occur in spin systems. This suggests that separation of defect pairs is a common trigger for phase transitions. Partially circumventing the activation barrier it reduces the hysteresis and may promote fluctuations within a temperature range increasing with decreasing dimensionality
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