Alien Registration- Daigle, Maria (Madawaska, Aroostook County)

https://digitalmaine.com/alien_docs/24934/thumbnail.jp

Physiological and Social Stress on Cognitive Performance

Humans are highly social creatures and this provides us with a number of benefits, such as protection and support, but it also brings new avenues for stress from social sources. Basic and translational neuroendocrine research has yielded a rich set of findings and a general understanding of how acute and chronic stress can result in reduced health, earlier aging, and earlier death. Although stress can be indexed by level of cortisol, the major stress hormone in humans, many interrelated physiological systems are involved in a stress response, including the cardio and vascular systems. Research toward greater understanding of stress buffering mechanisms holds value for improved human health in the face of entrenched social stressors. In particular, acute and chronic stress have consistently been found to impair cognitive performance, Many adults in high stress environments also face a changing social landscape during college years: changes in living partners, less control over noise, sleep, exercise, and nutrition. In this pilot investigation, we are interested in measuring the influences of acute stress on cognitive performance and whether social support, a factor that is modifiable, would be protective on the multi-systems relationships between stress and cognition. Broadly, we found (1) that higher levels of cortisol measured in saliva was associated with a faster return to resting levels of salivary cortisol (a measure of flexible, adaptive functioning of the central HPA stress system) after the stressor is removed and may also be associated with lower cortisol in the initial response to the stressor. In parallel, we found (2) that higher levels of cortisol were associated with impaired cognitive performance after the stress task, (3) finally, we found that those reporting high social support showed faster recovery to baseline in the cardiovascular systems and greater social support produced some buffering of stress response on their post-stress cognitive performance

The Brazilian Tunable Filter Imager for the SOAR telescope

This paper presents a new Tunable Filter Instrument for the SOAR telescope. The Brazilian Tunable Filter Imager (BTFI) is a versatile, new technology, tunable optical imager to be used in seeing-limited mode and at higher spatial fidelity using the SAM Ground-Layer Adaptive Optics facility at the SOAR telescope. The instrument opens important new science capabilities for the SOAR community, from studies of the centers of nearby galaxies and the insterstellar medium to statistical cosmological investigations. The BTFI takes advantage of three new technologies. The imaging Bragg Tunable Filter concept utilizes Volume Phase Holographic Gratings in a double-pass configuration, as a tunable filter, while a new Fabry-Perot (FP) concept involves technologies which allow a single FP etalon to act over a large range of interference orders and spectral resolutions. Both technologies will be in the same instrument. Spectral resolutions spanning the range between 25 and 30,000 can be achieved through the use of iBTF at low resolution and scanning FPs beyond R ~2,000. The third new technologies in BTFI is the use of EMCCDs for rapid and cyclically wavelength scanning thus mitigating the damaging effect of atmospheric variability through data acquisition. An additional important feature of the instrument is that it has two optical channels which allow for the simultaneous recording of the narrow-band, filtered image with the remaining (complementary) broad-band light. This avoids the uncertainties inherent in tunable filter imaging using a single detector. The system was designed to supply tunable filter imaging with a field-of-view of 3 arcmin on a side, sampled at 0.12" for direct Nasmyth seeing-limited area spectroscopy and for SAM's visitor instrument port for GLAO-fed area spectroscopy. The instrument has seen first light, as a SOAR visitor instrument. It is now in comissioning phase.Comment: accepted in PAS

High-entropy metal diborides: a new class of ultra-high temperature ceramics

Several equimolar, five-component, metal diborides were fabricated via high-energy ball milling and spark plasma sintering [Scientific Reports 6:37946 (2016)] or conventional pressure-less sintering. Most compositions synthesized, e.g., (Hf0.2Zr0.2Ta0.2Nb0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 and several others, processed single solid-solution phases of the hexagonal AlB2 structure, while a few other compositions yielded two or more boride phases. These materials represent a new type of ultra-high temperature ceramic (UHTC) as well as a new class of high-entropy materials that possess a non-cubic (hexagonal) and layered (quasi-2D) crystal structure (Fig. 1). Please click Additional Files below to see the full abstract

Temporal Trends and Factors Associated with Bisphosphonate Discontinuation and Restart

Adverse events related to long-term use of bisphosphonates have raised interest in temporary drug discontinuation. Trends in bisphosphonate discontinuation and restart, as well factors associated with these decisions, are not fully understood at a population level. We investigated temporal trends of bisphosphonate discontinuation from 2010 to 2015 and identified factors associated with discontinuation and restart of osteoporosis therapy. Our cohort consisted of long-term bisphosphonate users identified from 2010 to 2015 Medicare data. We defined discontinuation as 6512\u2009months without bisphosphonate prescription claims. We used conditional logistic regression to compare factors associated with alendronate discontinuation or osteoporosis therapy restart in the 120-day period preceding discontinuation or restart referent to the 120-day preceding control periods. Among 73,800 long-term bisphosphonate users, 59,251 (80.3%) used alendronate, 6806 (9.2%) risedronate, and 7743 (10.5%) zoledronic acid, exclusively. Overall, 26,281 (35.6%) discontinued bisphosphonates for at least 12\u2009months. Discontinuation of bisphosphonates increased from 1.7% in 2010, reaching a peak of 14% in 2012 with levels plateauing through 2015. The factors most strongly associated with discontinuation of alendronate were: benzodiazepine prescription (adjusted odds ratio [aOR] = 2.5; 95% confidence interval [CI] 2.1, 3.0), having a dual-energy X-ray absorptiometry (DXA) scan (aOR = 1.8; 95% CI 1.7, 2.0), and skilled nursing facility care utilization (aOR = 1.8; 95% CI 1.6, 2.1). The factors most strongly associated with restart of osteoporosis therapy were: having a DXA scan (aOR = 9.9; 95% CI 7.7, 12.6), sustaining a fragility fracture (aOR = 2.8; 95% CI 1.8, 4.5), and an osteoporosis or osteopenia diagnosis (aOR = 2.5; 95% CI 2.0, 3.1). Our national evaluation of bisphosphonate discontinuation showed that an increasing proportion of patients on long-term bisphosphonate therapy discontinue medications. The factors associated with discontinuation of alendronate were primarily related to worsening of overall health status, whereas traditional factors associated with worsening bone health were associated with restarting osteoporosis medication. \ua9 2019 American Society for Bone and Mineral Research

Measurements and simulations of the phonon thermal conductivity of entropy stabilized alloys

The phonon thermal conductivity of solids is intimately related to any changes in atomic scale periodicity. As a classic example, the phonon thermal conductivity of alloys can be greatly reduces as compared to that of the corresponding non-alloy parent materials. However, the improved mechanical properties and environmental stability of alloyed materials makes these multi-atom solids ideal for a wide variety of applications. In this sense, entropy stabilized oxides and high entropy diborides are promising new materials that have potential to withstand extreme environments consisting of high temperatures and pressures. In these novel materials, thermal characterization is essential for understanding and predicting performance at elevated temperatures, as the presence of multi atomic species (5+ different atoms) in these solid solutions could lead to drastically modified phonon scattering rates and thermal conductivities. In this talk, we present recent measurements and molecular dynamics simulations on multiple atom alloys, including entropy stabilized oxides and high entropy diborides. We use time-domain thermoreflectance (TDTR), and optical pump-probe technique, to measure the thermal conductivity of these various systems. We also demonstrate the ability to extend TDTR measurements to temperatures above 1000 deg. C. The TDTR measurements show drastic reductions in the thermal conductivity of these crystalline solid solution materials, approaching values of the amorphous phases. These reductions in thermal conductivity can not be explained by phonon-mass scattering alone. Thus, to investigate the nature of the reduction in thermal conductivity of these multi-atom solid solutions, we turn to classical molecular dynamics simulations. In agreement with the Klemens’ perturbation theory, the thermal conductivity reduction due to mass scattering alone is found to reach a critical point, whereby adding more impurity atoms in the solid solution does not reduce the thermal conductivity. A further decrease in thermal conductivity requires a change in local strain-field, which together with mass defect scattering can lead to ultralow thermal conductivities in solid solutions, which surpasses the theoretical minimum limit of the corresponding amorphous phases. These simulations qualitatively agree well with our experimental measurements, and add insight into the nature of phonon scattering in entropy stabilized materials. This work is supported by the U.S. Office of Naval Research MURI program (grant No. N00014-15-1-2863)

Phonon scattering mechanisms contributing to the low thermal conductivities of entropy stabilized oxides and high entropy carbides

The phonon thermal conductivity of solids is intimately related to any changes in atomic scale periodicity. As a classic example, the phonon thermal conductivity of alloys can be greatly reduced as compared to that of the corresponding non-alloy parent materials. However, the improved mechanical properties and environmental stability of alloyed materials makes these multi-atom solids ideal for a wide variety of applications. In this sense, entropy stabilized oxides and high entropy carbides are promising new materials that have potential to withstand extreme environments consisting of high temperatures and pressures. In these novel materials, thermal characterization is essential for understanding and predicting performance at elevated temperatures, as the presence of multi atomic species (5+ different atoms) in these solid solutions could lead to drastically modified phonon scattering rates and thermal conductivities. In this talk, we present recent measurements and molecular dynamics simulations on multiple atom alloys, including entropy stabilized oxides and high entropy diborides. We use time-domain thermoreflectance (TDTR), and optical pump-probe technique, to measure the thermal conductivity of these various systems. We also demonstrate the ability to extend TDTR measurements to temperatures above 1000 deg. C. The TDTR measurements show drastic reductions in the thermal conductivity of these crystalline solid solution materials, approaching values of the amorphous phases. These reductions in thermal conductivity can not be explained by phonon-mass scattering alone. Thus, to investigate the nature of the reduction in thermal conductivity of these multi-atom solid solutions, we turn to classical molecular dynamics simulations. In agreement with the Klemens’ perturbation theory, the thermal conductivity reduction due to mass scattering alone is found to reach a critical point, whereby adding more impurity atoms in the solid solution does not reduce the thermal conductivity. A further decrease in thermal conductivity requires a change in local strain-field, which together with mass defect scattering can lead to ultralow thermal conductivities in solid solutions, which surpasses the theoretical minimum limit of the corresponding amorphous phases. These simulations qualitatively agree well with our experimental measurements, and add insight into the nature of phonon scattering in entropy stabilized materials. This work is supported by the U.S. Office of Naval Research MURI program (grant No. N00014-15-1-2863

Markovian Dynamics on Complex Reaction Networks

Complex networks, comprised of individual elements that interact with each other through reaction channels, are ubiquitous across many scientific and engineering disciplines. Examples include biochemical, pharmacokinetic, epidemiological, ecological, social, neural, and multi-agent networks. A common approach to modeling such networks is by a master equation that governs the dynamic evolution of the joint probability mass function of the underling population process and naturally leads to Markovian dynamics for such process. Due however to the nonlinear nature of most reactions, the computation and analysis of the resulting stochastic population dynamics is a difficult task. This review article provides a coherent and comprehensive coverage of recently developed approaches and methods to tackle this problem. After reviewing a general framework for modeling Markovian reaction networks and giving specific examples, the authors present numerical and computational techniques capable of evaluating or approximating the solution of the master equation, discuss a recently developed approach for studying the stationary behavior of Markovian reaction networks using a potential energy landscape perspective, and provide an introduction to the emerging theory of thermodynamic analysis of such networks. Three representative problems of opinion formation, transcription regulation, and neural network dynamics are used as illustrative examples.Comment: 52 pages, 11 figures, for freely available MATLAB software, see http://www.cis.jhu.edu/~goutsias/CSS%20lab/software.htm

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe