310 research outputs found

    The Relationship between the Timing of Hydrocarbon Generation Between the Bristol Bay Depositional Basin and the Port Moller Area and Southern Portion of the Bristol Bay Basin of the Alaska Peninsula

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    The Alaska Peninsula has been the target of oil and gas exploration throughout much of the 20th century. Although most exploration efforts have focused on the Cook Inlet area, the geological setting of the Alaskan Peninsula suggests that economically viable resources may be located further south on the northern side bordering Bristol Bay (Port Moller area). This study investigates the relation of petroleum system elements between the northern and southern section of the Alaskan Peninsula with a particular focus on the potential for petroleum accumulation on the southern section close to Herendeen Bay. The analysis included the integration of a variety of geological and geophysical data from well logs, cores, and seismic profiles. I reconstructed the accumulation of sediment in the basin north of the peninsula and used backstripping subsidence analysis to identify periods of accelerated basement subsidence linked to regional tectonic extension. This analysis was then used to predict thermal history that was compared with thermal indicators from the wells. Basin inversion up to ~900 m since the Pliocene was predicted along the southern edge of the basin, resulting in peak temperatures being reached before the present day

    Stagnation-point heat-transfer rate predictions at aeroassist flight conditions

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    The results are presented for the stagnation-point heat-transfer rates used in the design process of the Aeroassist Flight Experiment (AFE) vehicle over its entire aeropass trajectory. The prediction methods used in this investigation demonstrate the application of computational fluid dynamics (CFD) techniques to a wide range of flight conditions and their usefulness in a design process. The heating rates were computed by a viscous-shock-layer (VSL) code at the lower altitudes and by a Navier-Stokes (N-S) code for the higher altitude cases. For both methods, finite-rate chemically reacting gas was considered, and a temperature-dependent wall-catalysis model was used. The wall temperature for each case was assumed to be radiative equilibrium temperature, based on total heating. The radiative heating was estimated by using a correlation equation. Wall slip was included in the N-S calculation method, and this method implicitly accounts for shock slip. The N-S/VSL combination of projection methods was established by comparison with the published benchmark flow-field code LAURA results at lower altitudes, and the direct simulation Monte Carlo results at higher altitude cases. To obtain the design heating rate over the entire forward face of the vehicle, a boundary-layer method (BLIMP code) that employs reacting chemistry and surface catalysis was used. The ratio of the VSL or N-S method prediction to that obtained from the boundary-layer method code at the stagnation point is used to define an adjustment factor, which accounts for the errors involved in using the boundary-layer method

    Physical Ergonomic And Mental Workload Factors Of Mobile Learning Affecting Performance Of Adult Distance Learners: Student Pers

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    Distance education is the fastest growing educational modality because of advances information technology has made over the past 25 years. Adult learners have become the fastest growing population in distance education. Adult learners, through technical tools and devices they use on the job, have become more digitally literate and mobile, making the ability to access class work on the go a necessity. Mobile learning or m-learning (learning that uses wireless, portable, mobile computing, and communication devices) is becoming an extension of distance learning, providing a channel for students to learn, communicate, and access educational material outside the traditional classroom environment. For adult learners, this modality allows them to take advantage of accessing material using mobile devices they use for job related activities. Despite the portability and readiness to information mobile devices provide its users, cognitive and physical ergonomic issues may impact learner performance. These issues may stem from information overload and physical discomfort from extended use of the mobile device which may negatively affect the overall success and satisfaction of m-learning environments. The purpose of this study was to examine the relationship between physical ergonomic discomfort, subjective workload, physiological response, and the impact on student performance while using mobile technology to read course material. Activity Theory was used as the theoretical foundation that guided the study. Eighty-four research participants, all over the age of 25, read a passage using one of two distance education modalities: desktop computer or mobile device. While reading the passage, one of three task load levels was imposed on participants: none, low or high. Each participant endured three trials, repeating the same task for each trial. After each trial, participants completed an achievement test and the NASA-TLX assessment. The results from this study provided evidence that mobile learning technologies with increased levels of task load introduced physical ergonomic discomfort and affected perceptions of mental workload in participants. The study also provided evidence that mobile learning technologies with increased levels of task load affected the performance (reading and learning) of participants. Study results provided insight into capabilities and limitations of students in their use of mobile devices for educational purposes. The limitations identified need to be further examined to aid in building successful m-learning environments with the goal of mobile device usage not affecting student performance

    CLTS plus : making CLTS ever more inclusive

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    If CLTS is to eliminate open defecation, issues of disability inclusion must be fully addressed. Research in Malawi aimed to discover if WASH practitioners, after a short training, could implement CLTS in a more inclusive way, and whether this made a difference to disabled people in the community, in terms of access to sanitation and hygiene facilities. After a 3-day training, CLTS implementers designed and implemented a CLTS+ Action Plan, in which additional triggering activities were introduced, and more attention paid to households with disabled and older people post-triggering. This CLTS+ intervention resulted in increased awareness among implementers and community members of the access needs of older and disabled people, and in adaptations to improve accessibility of some household latrines. Endline data will tell us whether this has resulted in improved outcomes for disabled and older people. Further piloting will be needed to explore how to incorporate this training into regular CLTS capacity building

    Individual and Familial Stressors Among Rural Nebraskan, Bilingual, Paraprofessional Educators

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    Individual (e.g., depression, learning styles) and familial (e.g., social support) factors affecting the psychosocial well-being of bilingual, rural Nebraska, paraprofessional educators were examined. Of 26 participants, 15 were first and 5 were second generation Hispanic immigrants. All were currently (n = 20) or formerly (n = 6) involved in an online, distance education, bachelor’s degree program in elementary education, with English as a second language certification. Results from data analyses are presented, as are suggestions for working with unique populations

    Fertility and Childbearing Among American Female Physicians

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    Background: Female physicians may experience unique challenges regarding fertility and family planning. We sought to determine childbearing patterns and decision-making among American female physicians. Materials and Methods: In 2012?2013, we surveyed a random sample of 600 female physicians who graduated medical school between 1995 and 2000. Primary outcome measures included fertility and childbearing history, reflections regarding decision-making, perceptions of workplace support, and estimations of childbearing potential. Results: Response rate was 54.5% (327/600). A majority (82.0%) of the sample were parents, 77.4% had biological children with an average of 2.3 children. Average age at medical school graduation was 27.5 years, at completion of training (completion of medical school, residency, and/or fellowship) was 31.6 years, and at first pregnancy was 30.4 years. Nearly one quarter (24.1%) of respondents who had attempted conception were diagnosed with infertility, with an average age at diagnosis of 33.7 years. Among those with infertility, 29.3% reported diminished ovarian reserve. When asked what they would do differently in retrospect, most respondents (56.8%) would do nothing differently regarding fertility/conception/childbearing, 28.6% would have attempted conception earlier, 17.1% would have gone into a different specialty, and 7.0% would have used cryopreservation to extend fertility. Fewer of those whose first pregnancy was in medical school perceived substantial workplace support (68.2%) than those whose first pregnancies followed training (88.6%). Conclusions: A substantial proportion of female physicians have faced infertility or have regrets about family planning decisions and career decision-making. Combining a medical career with motherhood continues to pose challenges, meriting further investigation and targeted support.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140144/1/jwh.2015.5638.pd

    Translational arrest due to cytoplasmic redox stress delays adaptation to growth on methanol and heterologous protein expression in a typical fed-batch culture of Pichia pastoris

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    Results We have followed a typical fed-batch induction regime for heterologous protein production under the control of the AOX1 promoter using both microarray and metabolomic analysis. The genetic constructs involved 1 and 3 copies of the TRY1 gene, encoding human trypsinogen. In small-scale laboratory cultures, expression of the 3 copy-number construct induced the unfolded protein response (UPR) sufficiently that titres of extracellular trypsinogen were lower in the 3-copy construct than with the 1-copy construct. In the fed-batch-culture, a similar pattern was observed, with higher expression from the 1-copy construct, but in this case there was no significant induction of UPR with the 3-copy strain. Analysis of the microarray and metabolomic information indicates that the 3-copy strain was undergoing cytoplasmic redox stress at the point of induction with methanol. In this Crabtree-negative yeast, this redox stress appeared to delay the adaptation to growth on methanol and supressed heterologous protein production, probably due to a block in translation. Conclusion Although redox imbalance as a result of artificially imposed hypoxia has previously been described, this is the first time that it has been characterised as a result of a transient metabolic imbalance and shown to involve a stress response which can lead to translational arrest. Without detailed analysis of the underlying processes it could easily have been mis-interpreted as secretion stress, transmitted through the UPR

    Rapid screening of cellular stress responses in recombinant Pichia pastoris strains using metabolite profiling

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    Heterologous protein production in the yeast Pichia pastoris can be limited by biological responses to high expression levels; the unfolded protein response (UPR) is a key determinant of the success of protein production in this organism. Here, we used untargeted NMR metabolic profiling (metabolomics) of a number of different recombinant strains, carried out in a miniaturized format suitable for screening-level experiments. We identified a number of metabolites (from both cell extracts and supernatants) which correlated well with UPR-relevant gene transcripts, and so could be potential biomarkers for future high-throughput screening of large numbers of P. pastoris clones.This study was wholly funded by the Bioprocessing Research Industry Club (BRIC), a partnership between BBSRC, EPSRC and a consortium of leading companies (http://www. bbsrc.ac.uk/business/collaborative-research/industry-clubs/bric/background.aspx, Grant reference BBF0049071)
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