67 research outputs found

    Late quaternary and future biome simulations for Alaska and eastern Russia

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    Thesis (M.S.) University of Alaska Fairbanks, 2016Arctic biomes across a region including Alaska and Eastern Russia were investigated using the BIOME4 biogeochemical and biogeography vegetation model. This study investigated past (the last 21,000 years), present, and future vegetation distributions in the study area, using climate forcing from five CMIP5 models (CCSM4, GISS-E2-R, MIROC-ESM, MPI-ESM, and MRI-CGCM3). The present-day BIOME4 simulations were generally consistent with current vegetation observations in the study region characterized by evergreen and deciduous taiga and shrub tundras. Paleoclimatological simulations were compared with pollen data samples collected in the study region. Pre-industrial biome simulations are generally similar to the modern reconstruction but differ by having more shrub tundra in both Russia and Alaska to the north, as well as less deciduous taiga in Alaska. Pre-industrial simulations were in good agreement with the pollen data. Mid-Holocene simulations place shrub tundras along the Arctic coast, and in some cases along the eastern coast of Russia. Simulations for the Mid-Holocene are in good agreement with pollen-based distributions of biomes. Simulations for the Last Glacial Maximum (LGM) show that the Bering Land Bridge was covered almost entirely by cushion forb, lichen and moss tundra, shrub tundra, and graminoid tundra. Three out of the five models’ climate data produce evergreen and deciduous taiga in what is now southwestern Alaska, however the pollen data does not support this. The distributions of cushion forb, lichen, and moss tundra and graminoid tundra differ noticeably between models, while shrub tundra distributions are generally similar. Future simulations of BIOME4 based on the RCP8.5 climate scenario indicate a northward shift of the treeline and a significant areal decrease of shrub tundra and graminoid tundra regions in the 21st century. Intrusions of cool mixed, deciduous, and conifer forests above 60°N, especially in southwest Alaska, were notable. Across eastern Russia, deciduous taiga begins to overtake evergreen taiga, except along the coastal regions where evergreen taiga remains the favored biome

    Alternate-Fueled Combustion-Sector Emissions

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    In order to meet rapidly growing demand for fuel, as well as address environmental concerns, the aviation industry has been testing alternate fuels for performance and technical usability in commercial and military aircraft. Currently, alternate aviation fuels must satisfy MIL-DTL- 83133F(2008) (military) or ASTM D 7566- Annex(2011) (commercial) standards and are termed drop-in fuel replacements. Fuel blends of up to 50% alternative fuel blended with petroleum (JP-8), which have become a practical alternative, are individually certified on the market. In order to make alternate fuels (and blends) a viable option for aviation, the fuel must be able to perform at a similar or higher level than traditional petroleum fuel. They also attempt to curb harmful emissions, and therefore a truly effective alternate fuel would emit at or under the level of currently used fuel. This paper analyzes data from gaseous and particulate emissions of an aircraft combustor sector. The data were evaluated at various inlet conditions, including variation in pressure and temperature, fuel-to-air ratios, and percent composition of alternate fuel. Traditional JP-8+100 data were taken as a baseline, and blends of JP- 8+100 with synthetic-paraffinic-kerosene (SPK) fuel (Fischer-Tropsch (FT)) were used for comparison. Gaseous and particulate emissions, as well as flame luminosity, were assessed for differences between FT composition of 0%, 50%, and 100%. The data showed that SPK fuel (a FT-derived fuel) had slightly lower harmful gaseous emissions, and smoke number information corroborated the hypothesis that SPK-FT fuels are cleaner burning fuels

    Alternate-Fueled Combustor-Sector Emissions

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    In order to meet rapidly growing demand for fuel, as well as address environmental concerns, the aviation industry has been testing alternate fuels for performance and technical usability in commercial and military aircraft. In order to make alternate fuels (and blends) a viable option for aviation, the fuel must be able to perform at a similar or higher level than traditional petroleum fuel. They also attempt to curb harmful emissions, and therefore a truly effective alternate fuel would emit at or under the level of currently used fuel. This report analyzes data from gaseous and particulate emissions of an aircraft combustor sector. The data were evaluated at various inlet conditions, including variation in pressure and temperature, fuel-to-air ratios, and percent composition of alternate fuel. Traditional JP-8+100 data were taken as a baseline, and blends of JP-8+100 with synthetic-paraffinic-kerosene (SPK) fuel (Fischer-Tropsch (FT)) were used for comparison. Gaseous and particulate emissions, as well as flame luminosity, were assessed for differences between FT composition of 0, 50, and 100 percent. The data show that SPK fuel (an FT-derived fuel) had slightly lower harmful gaseous emissions, and smoke number information corroborated the hypothesis that SPK-FT fuels are cleaner burning fuels

    Alternate-Fueled Combustor-Sector Performance

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    In order to realize alternative fueling for military and commercial use, the industry has set forth guidelines that must be met by each fuel. These aviation fueling requirements are outlined in MILDTL- 83133F(2008) or ASTM D 7566 Annex (2011) standards, and are classified as drop-in fuel replacements. This paper provides combustor performance data for synthetic-paraffinic-kerosene- (SPK-) type (Fisher-Tropsch (FT)) fuel and blends with JP-8+100, relative to JP-8+100 as baseline fueling. Data were taken at various nominal inlet conditions: 75 psia (0.52 MPa) at 500 F (533 K), 125 psia (0.86 MPa) at 625 F (603 K), 175 psia (1.21 MPa) at 725 F (658 K), and 225 psia (1.55 MPa) at 790 F (694 K). Combustor performance analysis assessments were made for the change in flame temperatures, combustor efficiency, wall temperatures, and exhaust plane temperatures at 3%, 4%, and 5% combustor pressure drop (% delta P) for fuel: air ratios (F/A) ranging from 0.010 to 0.025. Significant general trends show lower liner temperatures and higher flame and combustor outlet temperatures with increases in FT fueling relative to JP-8+100 fueling. The latter affects both turbine efficiency and blade/vane life

    Development of A Tool to Assess Resident Physicians’ Perceived Competence for Patient-centered Obesity Counseling

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    Physicians report a number of barriers to obesity counseling, among them low perceived competence in the ability to counsel. While there is increasing recognition of the need for resident training on counseling, implementation requires residency programs to have the necessary curricula and tools to evaluate training effectiveness. This study’s objective was to describe the development and psychometric testing of the Perceived Competence for Obesity Counseling (PCOC) scale. Items were generated based on constructs from the 5A’s counseling framework, review of the obesity literature, and expert opinion. The 20-item scale was piloted among 74 resident physicians. Exploratory factor analysis was conducted to identify the number and nature of factors in the scale.  Pearson's correlation was used to assess scale validity of the total scores and sub-scale scores association with residents’ overall confidence in counseling and outcome expectancy for obesity counseling. Analyses suggested a 3-factor solution. After the removal of cross loading items, eighteen items were retained; eleven items loaded on the first factor, four items on the second factor, and three on the third factor. Cronbach's alpha for the 18-item PCOC scale was 0.95 indicating internal consistency. The PCOC scale was significantly correlated with resident’s overall confidence in counseling (r = 0.60, p < 0.01) and outcome expectancy for obesity counseling (r = 0.41, p < 0.01). This pilot study suggests PCOC is holds promise as a valid and reliable measure of resident’s perceived competence for obesity counseling. Future studies are needed to assess the scale’s association with counseling skills

    Fatal self-injury in the United States, 1999–2018: Unmasking a national mental health crisis

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    Background Suicides by any method, plus ‘nonsuicide’ fatalities from drug self-intoxication (estimated from selected forensically undetermined and ‘accidental’ deaths), together represent self-injury mortality (SIM)—fatalities due to mental disorders or distress. SIM is especially important to examine given frequent undercounting of suicides amongst drug overdose deaths. We report suicide and SIM trends in the United States of America (US) during 1999–2018, portray interstate rate trends, and examine spatiotemporal (spacetime) diffusion or spread of the drug self-intoxication component of SIM, with attention to potential for differential suicide misclassification. Methods For this state-based, cross-sectional, panel time series, we used de-identified manner and underlying cause-of-death data for the 50 states and District of Columbia (DC) from CDC's Wide-ranging Online Data for Epidemiologic Research. Procedures comprised joinpoint regression to describe national trends; Spearman's rank-order correlation coefficient to assess interstate SIM and suicide rate congruence; and spacetime hierarchical modelling of the ‘nonsuicide’ SIM component. Findings The national annual average percentage change over the observation period in the SIM rate was 4.3% (95% CI: 3.3%, 5.4%; p6.0% increase (p<0.05). Interpretation Depiction of rising SIM trends across states and major regions unmasks a burgeoning national mental health crisis. Geographic variation is plausibly a partial product of local heterogeneity in toxic drug availability and the quality of medicolegal death investigations. Like COVID-19, the nation will only be able to prevent SIM by responding with collective, comprehensive, systemic approaches. Injury surveillance and prevention, mental health, and societal well-being are poorly served by the continuing segregation of substance use disorders from other mental disorders in clinical medicine and public health practice

    Urine Gastrin Releasing Peptide in the First Week Correlates with BPD and Post-Prematurity Respiratory Disease

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    Rationale: Bronchopulmonary dysplasia (BPD) is associated with post-prematurity respiratory disease (PRD) in survivors of extreme preterm birth. Identifying early biomarkers that correlate with later development of BPD and PRD may provide insights for intervention. In a preterm baboon model, elevated gastrin-releasing peptide (GRP) is associated with BPD, and GRP inhibition mitigates BPD occurrence. Objective: We performed a prospective cohort study to investigate whether urine GRP levels obtained in the first postnatal week were associated with BPD, PRD, and other urinary biomarkers of oxidative stress. Methods: Extremely low gestational age infants (23-28 completed weeks) were enrolled in a US multicenter observational study, The Prematurity and Respiratory Outcomes Program (http://clinicaltrials.gov/ct2/show/NCT01435187). We used multivariable logistic regression to examine the association between urine GRP in the first postnatal week and multiple respiratory outcomes: BPD, defined as supplemental oxygen use at 36 + 0 weeks postmenstrual age, and post-PRD, defined by positive quarterly surveys for increased medical utilization over the first year (PRD score). Results: A total of 109 of 257 (42%) infants had BPD, and 120 of 217 (55%) had PRD. On adjusted analysis, GRP level more than 80 was associated with BPD (adjusted odds ratio [aOR], 1.83; 95% confidence interval [CI], 1.03-3.25) and positive PRD score (aOR, 2.46; 95% CI, 1.35-4.48). Urine GRP levels correlated with duration of NICU ventilatory and oxygen support and with biomarkers of oxidative stress: allantoin and 8-hydroxydeoxyguanosine. Conclusions: Urine GRP in the first postnatal week was associated with concurrent urine biomarkers of oxidative stress and with later diagnoses of BPD and PRD

    Emerging Anthropogenic Influences on the Southcentral Alaska Temperature and Precipitation Extremes and Related Fires in 2019

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    The late-season extreme fire activity in Southcentral Alaska during 2019 was highly unusual and consequential. Firefighting operations had to be extended by a month in 2019 due to the extreme conditions of hot summer temperature and prolonged drought. The ongoing fires created poor air quality in the region containing most of Alaska’s population, leading to substantial impacts to public health. Suppression costs totaled over $70 million for Southcentral Alaska. This study’s main goals are to place the 2019 season into historical context, provide an attribution analysis, and assess future changes in wildfire risk in the region. The primary tools are meteorological observations and climate model simulations from the NCAR CESM Large Ensemble (LENS). The 2019 fire season in Southcentral Alaska included the hottest and driest June–August season over the 1979–2019 period. The LENS simulation analysis suggests that the anthropogenic signal of increased fire risk had not yet emerged in 2019 because of the CESM’s internal variability, but that the anthropogenic signal will emerge by the 2040–2080 period. The effect of warming temperatures dominates the effect of enhanced precipitation in the trend towards increased fire risk.The National Science Foundation (#OIA-1753748), the State of Alaska, the United States Geological Survey (G17AC00363), and the Alaska Climate Adaptation Science Center (G17AC00213) provided support for this study. NOAA supported this work through grants #NA16OAR4310162 (R.T., J.E.W., A.Y.) and #NA16OAR4310142 (U.S.B., P.A.B.)Ye

    Study protocol for a group randomized controlled trial of a classroom-based intervention aimed at preventing early risk factors for drug abuse: integrating effectiveness and implementation research

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    <p>Abstract</p> <p>Background</p> <p>While a number of preventive interventions delivered within schools have shown both short-term and long-term impact in epidemiologically based randomized field trials, programs are not often sustained with high-quality implementation over time. This study was designed to support two purposes. The first purpose was to test the effectiveness of a universal classroom-based intervention, the Whole Day First Grade Program (WD), aimed at two early antecedents to drug abuse and other problem behaviors, namely, aggressive, disruptive behavior and poor academic achievement. The second purpose--the focus of this paper--was to examine the utility of a multilevel structure to support high levels of implementation during the effectiveness trial, to sustain WD practices across additional years, and to train additional teachers in WD practices.</p> <p>Methods</p> <p>The WD intervention integrated three components, each previously tested separately: classroom behavior management; instruction, specifically reading; and family-classroom partnerships around behavior and learning. Teachers and students in 12 schools were randomly assigned to receive either the WD intervention or the standard first-grade program of the school system (SC). Three consecutive cohorts of first graders were randomized within schools to WD or SC classrooms and followed through the end of third grade to test the effectiveness of the WD intervention. Teacher practices were assessed over three years to examine the utility of the multilevel structure to support sustainability and scaling-up.</p> <p>Discussion</p> <p>The design employed in this trial appears to have considerable utility to provide data on WD effectiveness and to inform the field with regard to structures required to move evidence-based programs into practice.</p> <p>Trial Registration</p> <p><b>Clinical Trials Registration Number</b>: NCT00257088</p
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