4,644 research outputs found
How much more can sunspots tell us about the solar dynamo?
Sunspot observations inspired solar dynamo theory and continue to do so. Simply counting them established the sunspot cycle and its period. Latitudinal distributions introduced the tough constraint that the source of sunspots moves equator-ward as the cycle progresses. Observations of Hale's polarity law mandated hemispheric asymmetry. How much more can sunspots tell us about the solar dynamo? We draw attention to a few outstanding questions raised by inherent sunspot properties. Namely, how to explain sunspot rotation rates, the incoherence of follower spots, the longitudinal spacing of sunspot groups, and brightness trends within a given sunspot cycle. After reviewing the first several topics, we then present new results on the brightness of sunspots in Cycle 24 as observed with the Helioseismic Magnetic Imager (HMI). We compare these results to the sunspot brightness observed in Cycle 23 with the Michelson Doppler Imager (MDI). Next, we compare the minimum intensities of five sunspots simultaneously observed by the Hinode Solar Optical Telescope Spectropolarimeter (SOT-SP) and HMI to verify that the minimum brightness of sunspot umbrae correlates well to the maximum field strength. We then examine 90 and 52 sunspots in the north and south hemisphere, respectively, from 2010 - 2012. Finally, we conclude that the average maximum field strengths of umbra 40 Carrington Rotations into Cycle 24 are 2690 Gauss, virtually indistinguishable from the 2660 Gauss value observed at a similar time in Cycle 23 with MDI
Nontimber Forest Products in the United States
A quiet revolution is taking place in America\u27s forests. Once seen primarily as stands of timber, our woodlands are now prized as a rich source of a wide range of commodities, from wild mushrooms and maple sugar to hundreds of medicinal plants whose uses have only begun to be fully realized. Now as timber harvesting becomes more mechanized and requires less labor, the image of the lumberjack is being replaced by that of the forager. This book provides the first comprehensive examination of nontimber forest products (NTFPs) in the United States, illustrating their diverse importance, describing the people who harvest them, and outlining the steps that are being taken to ensure access to them. As the first extensive national overview of NTFP policy and management specific to the United States, it brings together research from numerous disciplines and analytical perspectives-such as economics, mycology, history, ecology, law, entomology, forestry, geography, and anthropology—in order to provide a cohesive picture of the current and potential role of NTFPs. The contributors review the state of scientific knowledge of NTFPs by offering a survey of commercial and noncommercial products, an overview of uses and users, and discussions of sustainable management issues associated with ecology, cultural traditions, forest policy, and commerce. They examine some of the major social, economic, and biological benefits of NTFPs, while also addressing the potential negative consequences of NTFP harvesting on forest ecosystems and on NTFP species populations. Within this wealth of information are rich accounts of NTFP use drawn from all parts of the American landscape—from the Pacific Northwest to the Caribbean. From honey production to a review of nontimber forest economies still active in the United States—such as the Ojibway harvest of plants recounted here—the book takes in the whole breadth of recent NTFP issues, including ecological concerns associated with the expansion of NTFP markets and NTFP tenure issues on federally managed lands. No other volume offers such a comprehensive overview of NTFPs in North America. By examining all aspects of these products, it contributes to the development of more sophisticated policy and management frameworks for not only ensuring their ongoing use but also protecting the future of our forests. Description Eric T. Jones is an instructor and research professor in the Department of Forest Ecosystems and Society at Oregon State University. Rebecca J. McLain is director of research at the National Policy Consensus Center at Portland State University. Susan Charnley is a research social scientist at the Pacific Northwest Research Station of the USDA Forest Service. James Weigand is an ecologist at the US Department of the Interior, Bureau of Land Management. With a New Preface by Eric T. Jones, Rebecca J. McLain, Susan Charnley, and James Weigand. This Kansas Open Books title is funded by a grant from the National Endowment for the Humanities and the Andrew W. Mellon Foundation Humanities Open Book Program.https://digitalcommons.pittstate.edu/kansas_open_books/1035/thumbnail.jp
Evaluation of the Nike+ FuelBand in energy expenditure and steps taken during exercise
ABSTRACT
PURPOSE: To assess the accuracy of the Nike+ FuelBand for estimating energy expenditure and steps taken during exercise. METHODS: Twenty subjects (age = 22.8 ± 2.4 yrs; body mass index = 24.9 ± 2.6 m/kg2) performed a progressive, three-interval treadmill test at three different speeds (2.0, 3.5, and 5.0 mph) with a 0% grade. Each stage lasted 8 min, with 3-min rest between intervals. Subjects wore the Nike+ FuelBand on the left wrist. Energy expenditure and steps were estimated by using its proprietary algorithm, and then compared with energy expenditure determined from indirect calorimetry and manual step count, which served as criterion measures. RESULTS: The Nike+ FuelBand significantly overestimated total energy expenditure by 31.1 kcal during the 5.0 mph interval (108.2 ± 29.4 kcal versus 77.0 ± 18.1 kcal, respectively; p \u3c .001). No differences were found between the Nike+ FuelBand and indirect calorimetry at 2.0 mph stage (26.8 ± 8.3 kcal versus 26.1 ± 6.2 kcal, respectively; p ≥ .05) or 3.5 mph stage (37.0 ± 10.5 steps versus 39.26 ± 8.80 steps, respectively; p ≥ .05). Concerning steps taken, the Nike+ FuelBand significantly underestimated steps compared to a manual count at the lower speed of 2.0 mph (321.8 ± 235.4 steps versus 760.3 ± 44.8 steps, respectively; p \u3c .001) No differences (p ≥ .05) were found at 3.5 mph (845.0 ± 210.5 steps versus 952.6 ± 60.44 steps, respectively) or 5.0 mph (1222 ± 61.5 steps versus 1239 ± 143.5 steps, respectively). CONCLUSIONS: The Nike+ FuelBand appears to provide an accurate assessment of energy expenditure at 2.0 mph and 3.5 mph, a common self-selected walking intensity range, but overestimates at a higher speed of 5.0 mph. The Nike+ FuelBand also appears to provide an accurate assessment of steps at speeds of 3.5 mph and 5.0 mph, but underestimates at 2.0 mph, most likely due to variation in arm swing motion during walking.
Key Words: Indirect Calorimetry, Energy Expenditure, Physical Activit
Adjoint-Based Design of Rotors using the Navier-Stokes Equations in a Noninertial Reference Frame
Optimization of rotorcraft flowfields using an adjoint method generally requires a time-dependent implementation of the equations. The current study examines an intermediate approach in which a subset of rotor flowfields are cast as steady problems in a noninertial reference frame. This technique permits the use of an existing steady-state adjoint formulation with minor modifications to perform sensitivity analyses. The formulation is valid for isolated rigid rotors in hover or where the freestream velocity is aligned with the axis of rotation. Discrete consistency of the implementation is demonstrated using comparisons with a complex-variable technique, and a number of single- and multi-point optimizations for the rotorcraft figure of merit function are shown for varying blade collective angles. Design trends are shown to remain consistent as the grid is refined
Costs Associated with Recurrent Epistaxis in a Patient with a Ventricular Assist Device
Mucosal bleeding is a well-known complication of having a ventricular assist device and commonly presents with epistaxis. Although the frequency of epistaxis as a complication in patients with a ventricular assist device has been documented in the literature, to our knowledge the cost of this complication has not been reported. This case report examines the financial burden of ventricular assist device-associated epistaxis in a single patient from September 2018 to December 2019 using ICD 10 diagnostic codes. The patient was found to have accumulated $138,020 in costs over 38 encounters. This case report not only highlights the recurrent nature and potential high cost of epistaxis in this patient population, but also identifies a target to reduce healthcare spending. Further research is needed to assess whether cheap and simple preventative measures such as nasal hygiene regimen can decrease the frequency and/or severity of epistaxis in the patients with a ventricular assist device
Femtosecond-Laser-Induced Spin-Polarized Electron Emission from a GaAs Tip
It is shown that focusing circularly-polarized 800 nm light pulses of 100 fs
duration on the tips of p-GaAs crystalline shards having no negative electron
affinity (NEA) activation results in electron emission that is both fast and
spin-polarized. The 400 fs duration of the emission process was determined by
pump/probe measurements. The three samples we investigated produced electron
polarizations of 13.1(9)%, 13.3(7)%, and 10.4(2)%. Emission currents ranged
between 50 pA and 3 nA with a sample bias of -100V and average laser power of
100 mW. The electron emission exhibited linear dichroism and was obtained under
moderate vacuum conditions, similar to that of metallic tips. This source of
spin-polarized electron pulses is "fast" in the sense that the electron
emission process is of comparable duration to the laser pulses that initiate
it.Comment: 5 pages, 3 figure
Counselor Allegiance and Client Expectancy in Neuroscience-Informed Cognitive-Behavior Therapy: A 12-Month Qualitative Follow-Up
This article presents summative findings from a 12-month multiphase mixed-methods pilot study examining counselor and client perceptions of neuroscience-informed cognitive-behavior therapy (nCBT) following clinical application. Results from the first 6 months of the study indicated that the counselor\u27s and client\u27s beliefs about the credibility and effectiveness of nCBT (i.e., expectancy) remained stable from pretreatment to 6 months into treatment. The fourth phase of data collection at the 12-month interval followed an explanatory sequential process whereby the qualitative data were connected to earlier merged quantitative data to better understand initial findings from the first 6 months of the study. Results indicate that counselors\u27 initial comprehension and familiarity with the model, counselor–client trust, counselor delivery and suggestion, and client willingness to practice outside of session were key components to the development of counselor and client belief (expectancy) in the model. Implications for nCBT theory development and application are discussed
Establishing the Learned Effect of Repeated Wingate Anaerobic Tests
The Wingate anaerobic test (WAnT) is a recognized and well-established measure of power output, muscular endurance, and fatigue. However, a learning effect could reduce the reliability of these measures. PURPOSE: To establish the number of WAnT trials needed to produce a learned effect. METHODS: Thirty-six apparently healthy college-aged men (n=20) and women (n=16) who had not previously performed a WAnT participated in five WAnT trials separated by a minimum of 72 hours. Peak Power (PP) and Mean Power (MP) were recorded for each trial. Resistance for trials was calculated at 7.5% of each respective participant’s weight. RESULTS: In men, paired samples t-test revealed PP increased on all trials (2-5) when compared to trial 1 (+44.66W, +49.19W, +55.80W, +63.95W; p=0.02, p=0.01, p=0.01, p=0.00, respectively). PP significantly increased from trial 1 to trial 2 (849.21±127.41 watts to 893.87±143.92 watts, p\u3c.05), but leveled thereafter with no significant differences between trials 2-5 (p\u3e.05). The same results were found for MP, with a significant increase from trial 1 to 2 (627.90±79.01 watts to 660.04±79.66 watts, p\u3c.01), but no differences found between trials 2-5 (p\u3e.05). There was a trend toward an elicited peak MP at trial 3 (p=.09, Cohen’s d= -.83). In women, the average PP and MP for trial 1 was 547.74±94.56 watts and 415.91±68.21 watts, respectively, with no significant differences found between trials (p\u3e.05). These results suggest that a learned effect is present within PP and MP until trial 2 of the WAnT, with a trend toward peak MP at trial 3 for male participants. CONCLUSION: Thereby, suggesting that when performing WAnT, utilizing less than 3 practice trials might elicit significant power increase in male participants due to this learned effect. Current data suggests that female participants elicit peak power at trial 1 of the WAnT, with no significant increase in subsequent trials. Additional research should be conducted in order to further investigate the non-significant trend of increasing power output across WAnT trials in male participants as well the lack of female learned response
Reduced swimming performance repeatedly evolves on loss of migration in landlocked populations of alewife
Author Posting. © University of Chicago, 2018. This article is posted here by permission of University of Chicago Press for personal use, not for redistribution. The definitive version was published in Physiological and Biochemical Zoology 91 (2018):814–825, doi:10.1086/696877.Whole-organism performance tasks are accomplished by the integration of morphological traits and physiological functions. Understanding how evolutionary change in morphology and physiology influences whole-organism performance will yield insight into the factors that shape its own evolution. We demonstrate that nonmigratory populations of alewife (Alosa pseudoharengus) have evolved reduced swimming performance in parallel, compared with their migratory ancestor. In contrast to theoretically and empirically based predictions, poor swimming among nonmigratory populations is unrelated to the evolution of osmoregulation and occurs despite the fact that nonmigratory alewives have a more fusiform (torpedo-like) body shape than their ancestor. Our results suggest that elimination of long-distance migration from the life cycle has shaped performance more than changes in body shape and physiological regulatory capacity.Funding was provided by the University of Connecticut’s
Department of Ecology and Evolutionary Biology and El
Muy Viejo.2019-01-3
- …