Now showing items 1-20 of 71021

    • Fatiga de enfermeras, el sueño y la salud, y garantizar la seguridad del paciente y del publico: Unir dos idiomas

      Baldwin, Carol M; Quan, Stuart F; Univ Arizona, Asthma & Airways Dis Res Ctr; Univ Arizona, Coll Med (Arizona Thoracic Society, 2019-12-29)
    • The effect of CPAP on HRQOL as measured by the Quality of Well-Being Self Administered Questionaire (QWB-SA)

      Batool-Anwar, Salma; Omobomi, Olabimpe; Quan, Stuart F; Univ Arizona, Coll Med; Univ Arizona, Asthma & Airways Dis Res Ctr (Arizona Thoracic Society, 2020-01-14)
      Background: To examine the effect of continuous positive airway pressure (CPAP) on Health-related quality of life (HRQoL) as measured by the Quality of Well Being Self-Administered questionnaire (QWB-SA). Methods: Participants from The Apnea Positive Pressure Long-term Efficacy Study (APPLES); a 6-month multicenter randomized, double-blinded intention to treat study, were included in this analysis. The participants with an apnea-hypopnea index >10 events/hour initially randomized to CPAP or Sham group were asked to complete QWB-SA at baseline, 2, 4, and 6-month visits. Results: There were no group differences among either the CPAP or Sham groups. "Mean age was 52±12 [SD] years, AHI 40±25 events/hr, BMI 32±7.1 kg/m2, and Epworth Sleepiness Score (ESS) 10±4 of 24 points." QWB-SA scores were available at baseline, and 2, 4 & 6 months after treatment in CPAP (n 558) and Sham CPAP (n 547) groups. There were no significant differences in QWB scores among mild, moderate or severe OSA participants at baseline. Modest improvement in QWB scores was noted at 2, 4 and 6- months among both Sham and CPAP groups (P <0.05). However, no differences were observed between Sham CPAP and CPAP at any time point. Comparison of the QWB-SA data from the current study with published data in populations with chronic illnesses demonstrated that the impact of OSA is no different than the effect of AIDS and arthritis. Conclusion: Although the QoL measured by the QWB-SA was impaired in OSA it did not have direct proportionality to OSA severity.
    • Perceptual Bias and Public Programs: The Case of the United States and Hospital Care

      Meier, Kenneth J.; Johnson, Austin P.; An, Seung‐Ho; Univ Arizona, Sch Govt & Publ Policy, Publ Management (WILEY, 2019-11)
      This article examines whether the public holds biased perceptions of public organizations (in this case, hospitals) in the United States and whether organizations get credit for positive results from program evaluations. Using an experimental design that replicates Hvidman and Andersen's 2016 Danish study, the study finds no negative public sector biases in the United States, but organizations are not given any credit for positive program evaluations. These results hold in two experimental replications. The implications of the findings for the measurement of public perceptions of government programs and for effective democratic governance are discussed.
    • Changes to the TDP-43 and FUS Interactomes Induced by DNA Damage

      Kawaguchi, Tetsuya; Rollins, Matthew G.; Moinpour, Mahta; Morera, Andres A.; Ebmeier, Christopher C.; Old, William M.; Schwartz, Jacob C.; Univ Arizona, Dept Mol & Cellular Biol; Univ Arizona, Dept Chem & Biochem (AMER CHEMICAL SOC, 2019-11-06)
      The RNA-binding proteins TDP-43 and FUS are tied as the thirdleading known genetic cause for amyotrophic lateral sclerosis (ALS), and TDP-43proteopathies are found in nearly all ALS patients. Both the natural function andcontribution to pathology for TDP-43 remain unclear. The intersection offunctions between TDP-43 and FUS can focus attention for those natural functionsmostly likely to be relevant to disease. Here, we compare the role played by TDP-43 and FUS, maintaining chromatin stability for dividing HEK293T cells. We alsodetermine and compare the interactomes of TDP-43 and FUS, quantitatingchanges in those before and after DNA damage. Finally, selected interactions withknown importance to DNA damage repair were validated by co-immunoprecipi-tation assays. This study uncovered TDP-43 and FUS binding to several factorsimportant to DNA repair mechanisms that can be replication-dependent,-independent, or both. These results provide further evidence that TDP-43 has an important role in DNA stability andprovide new ways that TDP-43 can bind to the machinery that guards DNA integrity in cells.
    • TDP-43 regulates transcription at protein-coding genes and Alu retrotransposons

      Morera, Andrés A; Ahmed, Nasiha S; Schwartz, Jacob C; Univ Arizona, Dept Mol & Cellular Biol; Univ Arizona, Dept Chem & Biochem (ELSEVIER, 2019-10)
      The 43-kDa transactive response DNA-binding protein (TDP-43) is an example of an RNA-binding protein that regulates RNA metabolism at multiple levels from transcription and splicing to translation. Its role in post-transcriptional RNA processing has been a primary focus of recent research, but its role in regulating transcription has been studied for only a few human genes. We characterized the effects of TDP-43 on transcription genome-wide and found that TDP-43 broadly affects transcription of protein-coding and noncoding RNA genes. Among protein-coding genes, the effects of TDP-43 were greatest for genes < 30 thousand base pairs in length. Surprisingly, we found that the loss of TDP-43 resulted in increased evidence for transcription activity near repetitive Alu elements found within expressed genes. The highest densities of affected Alu elements were found in the shorter genes, whose transcription was most affected by TDP-43. Thus, in addition to its role in post-transcriptional RNA processing, TDP-43 plays a critical role in maintaining the transcriptional stability of protein-coding genes and transposable DNA elements.
    • BrAPI-an application programming interface for plant breeding applications

      Selby, Peter; Abbeloos, Rafael; Backlund, Jan Erik; Salido, Martin Basterrechea; Bauchet, Guillaume; Benites-Alfaro, Omar E.; Birkett, Clay; Calaminos, Viana C.; Carceller, Pierre; Cornut, Guillaume; et al. (OXFORD UNIV PRESS, 2019-10-15)
      Motivation: Modern genomic breeding methods rely heavily on very large amounts of phenotyping and genotyping data, presenting new challenges in effective data management and integration. Recently, the size and complexity of datasets have increased significantly, with the result that data are often stored on multiple systems. As analyses of interest increasingly require aggregation of datasets from diverse sources, data exchange between disparate systems becomes a challenge. Results: To facilitate interoperability among breeding applications, we present the public plant Breeding Application Programming Interface (BrAPI). BrAPI is a standardized web service API specification. The development of BrAPI is a collaborative, community-based initiative involving a growing global community of over a hundred participants representing several dozen institutions and companies. Development of such a standard is recognized as critical to a number of important large breeding system initiatives as a foundational technology. The focus of the first version of the API is on providing services for connecting systems and retrieving basic breeding data including germplasm, study, observation, and marker data. A number of BrAPI-enabled applications, termed BrAPPs, have been written, that take advantage of the emerging support of BrAPI by many databases.
    • Human cardiac myosin-binding protein C restricts actin structural dynamics in a cooperative and phosphorylation-sensitive manner

      Bunch, Thomas A; Kanassatega, Rhye-Samuel; Lepak, Victoria C; Colson, Brett A; Univ Arizona, Dept Cellular & Mol Med (AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC, 2019-11-01)
      Cardiac myosin-binding protein C (cMyBP-C) is a thick filament-associated protein that influences actin-myosin interactions. cMyBP-C alters myofilament structure and contractile properties in a protein kinase A (PKA) phosphorylation-dependent manner. To determine the effects of cMyBP-C and its phosphorylation on the microsecond rotational dynamics of actin filaments, we attached a phosphorescent probe to F-actin at Cys-374 and performed transient phosphorescence anisotropy (TPA) experiments. Binding of cMyBP-C N-terminal domains (C0-C2) to labeled F-actin reduced rotational flexibility by 20-25°, indicated by increased final anisotropy of the TPA decay. The effects of C0-C2 on actin TPA were highly cooperative (n = ∼8), suggesting that the cMyBP-C N terminus impacts the rotational dynamics of actin spanning seven monomers (i.e. the length of tropomyosin). PKA-mediated phosphorylation of C0-C2 eliminated the cooperative effects on actin flexibility and modestly increased actin rotational rates. Effects of Ser to Asp phosphomimetic substitutions in the M-domain of C0-C2 on actin dynamics only partially recapitulated the phosphorylation effects. C0-C1 (lacking M-domain/C2) similarly exhibited reduced cooperativity, but not as reduced as by phosphorylated C0-C2. These results suggest an important regulatory role of the M-domain in cMyBP-C effects on actin structural dynamics. In contrast, phosphomimetic substitution of the glycogen synthase kinase (GSK3β) site in the Pro/Ala-rich linker of C0-C2 did not significantly affect the TPA results. We conclude that cMyBP-C binding and PKA-mediated phosphorylation can modulate actin dynamics. We propose that these N-terminal cMyBP-C-induced changes in actin dynamics help explain the functional effects of cMyBP-C phosphorylation on actin-myosin interactions.
    • Alignment of stakeholder agendas to facilitate the adoption of school-supervised asthma therapy

      Trivedi, Michelle; Patel, Janki; Hoque, Shushmita; Mizrahi, Raphael; Biebel, Kathleen; Phipatanakul, Wanda; Lemon, Stephenie C; Byatt, Nancy; Gerald, Lynn B; Rosal, Milagros; et al. (WILEY, 2019-12-19)
      Background School-supervised inhaled corticosteroid (ICS) therapy improves pediatric asthma medication adherence, outcomes, and morbidity. However, school-supervised ICS therapy has not been widely adopted into practice. We developed Asthma Link (TM) as a sustainable, low-cost model of school-supervised asthma therapy, designed for real-world adoption. Initial outcomes of Asthma Link (TM) demonstrated a significant improvement in health outcomes. Objective In this study, we examined the perspectives of Asthma Link (TM) participants to identify systems-level barriers and facilitators to refine the Asthma Link (TM) protocol and facilitate real-world uptake of school-supervised asthma therapy. Methods Using qualitative research methods, we interviewed 29 participants in Asthma Link (TM) from 2016 to 2018. Semi-structured interviews were conducted over the phone. Interviews were transcribed and the transcripts were coded to identify major themes within and across stakeholder groups. Results Stakeholders agreed on many facilitators for successful Asthma Link (TM) execution including the brief and easy to follow procedures and the perceived beneficial health impacts for children involved. Some of the barriers identified were deviations from the protocol and insurance companies denying coverage for two inhalers. However, the participants did propose solutions to address these barriers. Conclusion Asthma Link (TM) is a low-cost, sustainable model of school-supervised asthma therapy that leverages the established infrastructure and collaboration of medical providers, school staff, and families. In this study, we elicited the perspectives from these stakeholder groups and identified an agreement in several facilitators, barriers, and proposed solutions that will ultimately inform refinement of the program protocol and support real-world adoption of Asthma Link (TM) and other similar models.
    • Geologic Map of the Blythe 7.5' Quadrangle, La Paz County, Arizona and Riverside County, California

      Block, D.; Gootee, B.F.; House, P.K.; Pearthree, P.A.; Arizona Geological Survey; U.S. Geological Survey (Arizona Geological Survey (Tucson, AZ), 2019-12)
    • C-infinity Smoothing for Weak Solutions of the Inhomogeneous Landau Equation

      Henderson, Christopher; Snelson, Stanley; Univ Arizona, Dept Math (SPRINGER, 2019-11-06)
      We consider the spatially inhomogeneous Landau equation with initial data that is bounded by a Gaussian in the velocity variable. In the case of moderately soft potentials, we show that weak solutions immediately become smooth, and remain smooth as long as the mass, energy, and entropy densities remain under control. For very soft potentials, we obtain the same conclusion with the additional assumption that a sufficiently high moment of the solution in the velocity variable remains bounded. Our proof relies on the iteration of local Schauder-type estimates.
    • Correlating Removal Rate to Directivity in Copper Chemical Mechanical Planarization

      McAllister, Jeffrey; Dadashazar, Hossein; Sampurno, Yasa; Gyu Kim, Sung; Park, Dongyoul; Kwon, Heeill; Lee, Yongbin; Philipossian, Ara; Univ Arizona, Dept Chem & Environm Engn (ELECTROCHEMICAL SOC INC, 2019-11-19)
      The relationship between directivity (Delta) and removal rate (RR) during copper chemical mechanical planarization (CMP) was investigated. We measured the high-frequency shear and normal forces generated by stick-slip (which has been routinely used to explain micro- and nano-scale interactions that lead to material removal), and found there to be a strong correlation between Delta (defined as the ratio of variances in shear force to those of normal force) and copper RR so long as the tribological mechanism remained constant. In cases where the tribological mechanism changed from "boundary lubrication" (BL) to "mixed lubrication" (ML), the slope of the straight-line correlation between Delta and RR was maintained, albeit it was shifted significantly lower. This was due to the ML regime consisting of hydrostatic or buoyant forces supporting the wafer, which led to less variability in frictional forces or less stick-slip events. Additionally, it was found that Delta and RR increased with sliding velocity while in BL due to an increase in stick-slip events. Conversely, Delta and RR decreased at lower sliding velocities while in ML due to an increase in hydrostatic or buoyant force supporting the wafer. (C) 2019 The Electrochemical Society.
    • Impact of Polisher Kinematics and Conditioner Disc Designs on Fluid Transport during Chemical Mechanical Planarization

      McAllister, Jeffrey; Dadashazar, Hossein; Mariscal, Juan Cristobal; Sampurno, Yasa; Philipossian, Ara; Univ Arizona, Dept Chem & Environm Engn (ELECTROCHEMICAL SOC INC, 2019-11-25)
      Fluid film thicknesses were measured and general flow patterns were analyzed during conditioning on a polishing pad using a recently developed UV-enhanced fluorescence experimental technique. The method was used to analyze how conditioners with different working face designs and polisher kinematics (platen angular velocities) affected fluid flow characteristics on the pad surface. In general, fluid film thicknesses followed the same general trends across the pad surface for both disc designs and platen speeds. Regardless of the parameters used, the fluid film was the thickest in sections nearest to the wafer track and was significantly thinner near the center and edge of the pad. For both discs, the time for film thicknesses to reach steady-state increased with distance from the radius. In general, the full-face conditioner had a smaller maximum attainable fluid thickness (MAFT) and time to reach steady-state (TTRSS) as it most effectively expelled (i.e. squeegeed) the fluid off the pad surface. In contrast, the partial-face conditioner had a larger MAFT and TTRSS as its more intricate design allowed for greater fluid retention and generated more back-flow. (c) 2019 The Electrochemical Society.
    • Parametric uncertainty assessment in hydrological modeling using the generalized polynomial chaos expansion

      Hu, Junjun; Chen, Sheng; Behrangi, Ali; Yuan, Huiling; Univ Arizona, Dept Hydrol & Atmospher Sci (ELSEVIER, 2019-12)
      An integrated framework is proposed for parametric uncertainty analysis in hydrological modeling using a generalized polynomial chaos expansion (PCE) approach. PCE represents model output as a polynomial expression in terms of critical random variables that are determined by parameter uncertainties, thus offers an efficient way of sampling without running the original model, which is appealing to computationally expensive models. To demonstrate the applicability of generalized PCE approach, both second- and third-order PCEs (PCE-2 and PCE-3) are constructed for Xinanjiang hydrological model using three selected uncertain parameters. Uncertainties in streamflow predictions are assessed by sampling the random inputs. Results show that: (1) both PCE-2 and PCE-3 are capable of capturing the uncertainty information in hydrological predictions, generating consistent mean, variance, skewness and kurtosis estimates with the standard Monte Carlo (MC) methodology; (2) Using more collocation points and more polynomial terms, PCE-3 approximation slightly improves the model simulation and provides more matched distribution with that of MC compared to PCE-2; (3) the computational cost using the PCE approach is greatly reduced by 71% (20%) with PCE-2 (PCE-3). In general, PCE-2 is recommended to serve as a good surrogate model for Xinanjiang hydrological modelling in future with much higher computation speed, more efficient sampling, and compatible approximation results.
    • Initial assessment of an interprofessional team-delivered telehealth program for patients with epilepsy

      Axon, David Rhys; Taylor, Ann M; Vo, Dylan; Bingham, Jennifer; Univ Arizona, Coll Pharm (ELSEVIER, 2019-12-01)
      Introduction: Epilepsy affects 3.5 million people in the United States (US). Rural-dwelling individuals have less access to healthcare and consequently poorer health outcomes. This study describes the outcomes of an interprofessional telehealth program for rural-dwelling individuals with epilepsy in one US state. Methods: An academic medication therapy management pharmacist provided clinical services to rural-dwelling individuals with epilepsy between November 2015 and June 2018, using video-conferencing technology and follow-up telephonic consultation. Data collected included: demographics, prescribed seizure medications, comorbidities, drug-drug and drug-disease interactions, adverse drug reactions, therapeutic duplications, doserelated safety concerns, adherence concerns, and recommendations to resolve identified issues. Data were summarized using appropriate descriptive statistics. Results: A total of 168 patients (51% male, mean age 28 +/- 15 years), participated in this pilot study. Most participants (94%) were prescribed at least one seizure medication including: benzodiazepines (n = 89), Iamotrigine (n = 58), and levetiracetam (n = 56). The majority (55%) had at least one comorbidity including: mood disorders (n = 49) and psychiatric disorders (n = 26). Common medications with reported precautions for people with a seizure history were: selective serotonin reuptake inhibitors (n = 18), second-generation atypical antipsychotics (n = 17) and benzodiazepines (n = 16). Participants had at least one: drug-disease interaction (33%), drug-drug interaction (54%), adverse drug reaction (37%), therapeutic duplication (13%); dose-related safety concerns (35%); and medication utilization concerns (13%). Discussion: This pharmacist-delivered pilot program was effective in: reaching underserved patients with epilepsy, identifying and recommending resolutions to medication-related problems, and demonstrating the value of pharmacists in an interprofessional team. Further work is warranted to identify telehealth strategies to reduce medication associated problems.
    • Social contributors to cardiometabolic diseases in indigenous populations: an international Delphi study

      Stoner, L; Matheson, A G; Perry, L G; Williams, M A; McManus, A; Holdaway, M; Dimer, L; Joe, J R; Maiorana, A; Univ Arizona, Dept Family & Community Med (W B SAUNDERS CO LTD, 2019-11-01)
      Objective: The objective of this study was to identify priority social factors contributing to indigenous cardiometabolic diseases. Study design: A three-round Delphi process was used to consolidate and compare the opinions of 60 experts in indigenous cardiometabolic health from Australia, New Zealand and the United States. Methods: Round one: three open-ended questions: (i) historical, (ii) economic and (iii) sociocultural factor contributors to cardiometabolic disease risk. Round two: a structured questionnaire based on the results from the first round; items were ranked according to perceived importance. Final round: the items were reranked after receiving the summary feedback. Results: Several key findings were identified: (i) an important historical factor is marginalisation and disempowerment; (ii) in terms of economic and sociocultural factors, the panellists came to the consensus that the socio-economic status and educational inequalities are important; and (iii) while consensus was not reached, economic and educational factors were also perceived to be historically influential. Conclusion: These findings support the need for multilevel health promotion policy. For example, tackling financial barriers that limit the access to health-promoting resources, combined with improving literacy skills to permit understanding of health education. (C) 2018 The Royal Society for Public Health. Published by Elsevier Ltd. All rights reserved.
    • Beavers alter stream macroinvertebrate communities in north-eastern Utah

      Washko, Susan; Roper, Brett; Atwood, Trisha B.; Univ Arizona, Sch Nat Resources & Environm (WILEY, 2019-12-15)
      Understanding changes in macroinvertebrate communities is important because they play a large role in stream ecosystem functioning, and they are an important food resource for fish. Beaver-induced changes to stream morphology could alter macroinvertebrate communities, which in turn could affect food webs and ecosystem function. However, studies investigating the effects of North American beaver activities on macroinvertebrates are rare in the inter-mountain west, an area with high potential for beaver-assisted restoration. The aim of this study was to quantify differences in the macroinvertebrate community between unaltered segments of streams and within beaver ponds in north-eastern Utah, U.S.A. We assessed macroinvertebrate species richness, biomass, density, functional feeding group composition, mobility group composition, and macroinvertebrate habitat characteristics to test the hypothesis that macroinvertebrate communities will differ among habitat types (undammed stream segments and beaver ponds) in beaver-occupied streams. Beaver pond communities significantly differed from lotic reach communities in many ways. Beaver ponds were less diverse with 25% fewer species. Although there was variability among streams, in general, beaver ponds had 75% fewer individuals and 90% lower total macroinvertebrate biomass compared to lotic reaches. Regarding functional feeding groups, beaver ponds contained more engulfers, while lotic reaches contained more scrapers, filterers, and gatherers. For mobility groups, beaver ponds had more sprawlers, while lotic reaches had more clingers. Swimmers were also more prevalent in lotic reaches, although this is probably due to the abundance of Baetis within lotic reaches. More beaver pond taxa were classified as lentic-dwelling insects, while more lotic reach taxa were categorised as preferring lotic habitats. The creation of ponds by beavers fundamentally altered the macroinvertebrate community in north-eastern Utah streams. Such changes to stream macroinvertebrate communities suggest that recolonisation of beavers across North America may be altering stream functioning and food webs. Our study highlights the need to further investigate the effects of beaver recolonisation on stream communities.
    • Flickers of Freedom and Moral Luck

      Sartorio, Carolina; Univ Arizona (WILEY PERIODICALS, 2019-07-28)
    • The effect of sleep deficiency on esophageal acid exposure of healthy controls and patients with gastroesophageal reflux disease

      Yamasaki, Takahisa; Quan, Stuart F; Fass, Ronnie; Univ Arizona, Coll Med, Asthma & Airway Dis Res Ctr (WILEY, 2019-12-01)
      Background Studies have demonstrated a bi-directional relationship between sleep deficiency and gastroesophageal reflux disease (GERD). However, there is limited data on how sleep deficiency affects esophageal acid exposure. We aimed to compare the effect of sleep deficiency on esophageal acid exposure of healthy controls versus GERD patients. Methods Eleven patients from each of 2 groups were randomized to undergo pH-testing after 2 consecutive days of 7-8 hours of sleep per night (normal sleep) or 2 consecutive days of 4 hours of sleep per night (deficient sleep). All subjects then crossed over to the other arm, after 1-week washout period. While subjects were instructed to follow the study sleep protocol, actigraphy ensured subjects followed required sleeping time during study period. Key Results After normal sleep, all healthy controls had normal esophageal acid exposure. After deficient sleep, 5 healthy controls demonstrated an abnormal pH test. Overall, there was a significant increase in reflux parameters after deficient sleep as compared with normal sleep (% total time-6.15 +/- 5.89 vs 1.74 +/- 1.54, % upright time-4.72 +/- 5.36 vs 0.87 +/- 1.28, P < .05, respectively). After normal sleep, 6 GERD patients (54.5%) demonstrated an abnormal pH-testing. After deficient sleep, 10 GERD patients (90.9%) demonstrated an abnormal pH-testing. GERD patients demonstrated significantly higher reflux parameters than healthy controls after normal sleep (% total time-5.02 +/- 3.45 vs 1.74 +/- 1.54, % upright time-4.11 +/- 3.98 vs 0.87 +/- 1.28, P < .05, respectively). Conclusions & Inferences Sleep deficiency increased esophageal acid exposure in both healthy controls and GERD patients. Sleep deficiency also resulted in abnormal pH tests in almost half of healthy controls.
    • Economic performance of membrane distillation configurations in optimal solar thermal desalination systems

      Karanikola, Vasiliki; Moore, Sarah E.; Deshmukh, Akshay; Arnold, Robert G.; Elimelech, Menachem; Sáez, A. Eduardo; Univ Arizona, Dept Chem & Environm Engn (ELSEVIER, 2019-12-15)
      In this study we provide a comprehensive evaluation of the economic performance and viability of solar membrane distillation (MD). To achieve this goal, process models based on mass and energy balances were used to find the minimum cost of water in MD systems. Three MD configurations: direct contact, sweeping gas, and vacuum MD, were compared in terms of economic cost and energy requirements in optimized, solar-driven desalination systems constrained to produce 10 m(3) d(-1) of distillate from 3.5% or 15% salinity water. Simulation results were used to calculate the water production cost as a function of 13 decision variables, including equipment size and operational variables. Non-linear optimization was performed using the particle swarm algorithm to minimize water production costs and identify optimal values for all decision variables. Results indicate that vacuum MD outperforms alternative MD configurations both economically and energetically, desalting water at a cost of less than $15 per cubic meter of product water (both initial salt levels). The highest fraction of total cost for all configurations at each salinity level was attributed to the solar thermal collectors-approximately 25% of the total present value cost. Storing energy in any form was economically unfavorable; the optimization scheme selected the smallest battery and hot water tank size allowed. Direct contact MD consumed significantly more energy (primarily thermal) than other MD forms, leading to higher system economic costs as well.
    • Linear Stability in the Inner Heliosphere: Helios Re-evaluated

      Klein, K. G.; Martinović, M.; Stansby, D.; Horbury, T. S.; Univ Arizona, Lunar & Planetary Lab; Univ Arizona, Dept Planetary Sci (IOP PUBLISHING LTD, 2019-12-23)
      Wave–particle instabilities driven by departures from local thermodynamic equilibrium have been conjectured to play a role in governing solar wind dynamics. We calculate the statistical variation of linear stability over a large subset of Helios I and II observations of the fast solar wind using a numerical evaluation of the Nyquist stability criterion, accounting for multiple sources of free energy associated with protons and helium including temperature anisotropies and relative drifts. We find that 88% of the surveyed intervals are linearly unstable. The median growth rate of the unstable modes is within an order of magnitude of the turbulent transfer rate, fast enough to potentially impact the turbulent scale-to-scale energy transfer. This rate does not significantly change with radial distance, though the nature of the unstable modes, and which ion components are responsible for driving the instabilities, does vary. The effect of ion–ion collisions on stability is found to be significant; collisionally young wind is much more unstable than collisionally old wind, with very different kinds of instabilities present in the two kinds of wind.