2,765 research outputs found

    Increasing occurrence of cold and warm extremes during the recent global warming slowdown.

    Get PDF
    The recent levelling of global mean temperatures after the late 1990s, the so-called global warming hiatus or slowdown, ignited a surge of scientific interest into natural global mean surface temperature variability, observed temperature biases, and climate communication, but many questions remain about how these findings relate to variations in more societally relevant temperature extremes. Here we show that both summertime warm and wintertime cold extreme occurrences increased over land during the so-called hiatus period, and that these increases occurred for distinct reasons. The increase in cold extremes is associated with an atmospheric circulation pattern resembling the warm Arctic-cold continents pattern, whereas the increase in warm extremes is tied to a pattern of sea surface temperatures resembling the Atlantic Multidecadal Oscillation. These findings indicate that large-scale factors responsible for the most societally relevant temperature variations over continents are distinct from those of global mean surface temperature

    Dynamical prediction of Arctic sea ice modes of variability

    Get PDF
    This study explores the prediction skill of the northern hemisphere (NH) sea ice thickness (SIT) modes of variability in a state-of-the-art coupled forecast system with respect to two statistical forecast benchmarks. Application of the K-means clustering method on a historical reconstruction of SIT from 1958 to 2013, produced by an ocean-sea-ice general circulation model, identifies three Arctic SIT clusters or modes of climate variability. These SIT modes have consistent patterns in different calendar months and their discrete time series of occurrences show persistence on intraseasonal to interannual time scales. We use the EC-Earth2.3 coupled climate model to produce five-member 12-month-long monthly forecasts of the NH SIT modes initialized on 1 May and 1 November every year from 1979 to 2010. We use a three-state first-order Markov chain and climatological probability forecasts determined from the historical SIT mode reconstruction as two statistical reference forecasts. The analysis of ranked probability skill scores (RPSSs) relating these three forecast systems shows that the dynamical SIT mode forecasts typically have a higher skill than the Markov chain forecasts, which are overall better than climatological forecasts. The evolution of RPSS in forecast time indicates that the transition from the sea-ice melting season to growing season in the EC-Earth2.3 forecasts, with respect to the Markov chain model, typically leads to the improvement of prediction skill. The reliability diagrams overall show better reliability of the dynamical forecasts than that of the Markov chain model, especially for 1 May start dates, while dynamical forecasts with 1 November start dates are overconfident. The relative operating characteristics (ROC) diagrams confirm this hierarchy of forecast skill among these three forecast systems. Furthermore, ROC diagrams stratified in groups of 3 sequential forecast months show that Arctic SIT mode forecasts initialized on 1 November typically lose resolution with forecast time more slowly than forecasts initialized on 1 May.The authors acknowledge funding support for this study from the PICA-ICE (CGL2012-31987) Project funded by the Ministry of Economy and Competitiveness of Spain, the SPECS (GA 308378) Project funded by the Seventh Framework Programme (FP7) and the PRIMAVERA (GA 641727) project funded by the Horizon 2020 framework of the European Commission. NSF was a recipient of the Juan de la Cierva-incorporación postdoctoral fellowship from the Ministry of Economy and Competitiveness of Spain. NCJ was supported by NOAA’s Climate Program Office. The authors acknowledge the computer resources, technical expertise and assistance provided by the Red Española de Supercomputación through the Barcelona Supercomputing Center in Barcelona, Spain, and by the European Centre for Medium–Range Weather Forecasts in Reading, UK. The authors thank Stefan Siegert and an anonymous reviewer for their constructive inputs, and Francois Massonnet, Javier Garcia-Serrano, Omar Bellprat, Louis-Philippe Caron, Matthieu Chevallier, Torben Koening, Mitch Bushuk and Jonathan Day for valuable discussions. Analyzed global sea ice historical reconstruction with ORCA1 NEMO-LIM2 is available upon request.Peer ReviewedPostprint (published version

    Sleeping time is associated with functional limitations in a national sample of older Americans

    Get PDF
    Background: Engaging in healthy behaviors may help to preserve function during aging; however, it is not well understood how sleeping time is associated with functional capacity in older adults. Aims: We sought to determine the association of sleeping time on functional limitation in a national sample of older Americans. Methods: The analytical sample included 6,020 adults aged at least 65 years who participated in the 2007-2016 waves of the National Health and Nutrition Examination Survey. Respondents indicated their hours of sleep/week night and were categorized as \u3c5, 5-6.5, 7-8, 8.5-9, and \u3e9 hours of sleep/week night. Ability to complete 19 functional tasks including basic activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility activities, and general physical activities were also self-reported. A covariate-adjusted logistic model analyzed the associations between each sleeping time category and functional limitation. Results: Relative to those reporting 7-8 hours of sleep/week night, older Americans reporting \u3c5, 5-6.5, 8.5-9, and \u3e9 hours of sleep/week night had 2.02 (95% confidence interval (CI): 1.26, 3.21), 1.25 (CI: 1.02, 1.53), 1.60 (CI: 1.21, 2.12), and 3.21 (CI: 2.12, 4.87) greater odds for functional limitation, respectively. Discussion: Sleep should be recognized as a health factor that may reflect functional capacity in older adults. Healthcare providers should discuss the importance of optimal sleep with their older patients and older adults should practice healthy sleeping behaviors for preserving function. Conclusions: Not meeting optimal sleep recommendations is associated with functional limitations in older Americans

    Rapid 20th century warming reverses 900-year cooling in the Gulf of Maine

    Get PDF
    The Gulf of Maine, located in the western North Atlantic, has undergone recent, rapid ocean warming but the lack of long-term, instrumental records hampers the ability to put these significant hydrographic changes into context. Here we present multiple 300-year long geochemical records (oxygen, nitrogen, and previously published radiocarbon isotopes) measured in absolutely-dated Arctica islandica shells from the western Gulf of Maine. These records, in combination with climate model simulations, suggest that the Gulf of Maine underwent a long-term cooling over most of the last 1000 years, driven primarily by volcanic forcing and North Atlantic ocean dynamics. This cooling trend was reversed by warming beginning in the late 1800s, likely due to increased atmospheric greenhouse gas concentrations and changes in western North Atlantic circulation. The climate model simulations suggest that the warming over the last century was more rapid than almost any other 100-year period in the last 1000 years in the region

    Physiological Responses Underlying the Perception of Effort during Moderate and Heavy Intensity Cycle Ergometry

    Get PDF
    This study examined patterns of responses for physiological and perceptual variables during cycle ergometry at a constant rate of perceived exertion (RPE) within the moderate and heavy exercise intensity domains. Nineteen (mean age 21.3 ± 0.5 years; 43.4 ± 2.0 mL·kg−1·min−1 VO2Peak) moderately trained cyclists performed an incremental test to exhaustion and two 60 min constant RPE rides at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above the GET (RPEGET+15%). Oxygen consumption (VO2), respiratory exchange ratio (RER), heart rate (HR), minute ventilation (VE), breathing frequency (FB), and power output (PO) were monitored throughout the rides. Polynomial regression analyses showed VO2, RER, HR, and VE (correlation = −0.85 to −0.98) tracked the decreases in PO required to maintain a constant RPE. Only FB tracked RPE during the moderate and heavy intensity rides. Repeated measures ANOVAs indicated that VO2 during the 60 min rides at RPEGET was not different (p \u3e 0.05) from VO2 at GET from the incremental test to exhaustion. Thus, monitoring intensity using an RPE associated with the GET is sustainable for up to 60 min of cycling exercise and a common mechanism may mediate FB and the perception of effort during moderate and heavy intensity cycle ergometry

    Physiological Responses Underlying the Perception of Effort during Moderate and Heavy Intensity Cycle Ergometry

    Get PDF
    This study examined patterns of responses for physiological and perceptual variables during cycle ergometry at a constant rate of perceived exertion (RPE) within the moderate and heavy exercise intensity domains. Nineteen (mean age 21.3 ± 0.5 years; 43.4 ± 2.0 mL·kg−1·min−1 VO2Peak) moderately trained cyclists performed an incremental test to exhaustion and two 60 min constant RPE rides at the RPE corresponding to the gas exchange threshold (RPEGET) and 15% above the GET (RPEGET+15%). Oxygen consumption (VO2), respiratory exchange ratio (RER), heart rate (HR), minute ventilation (VE), breathing frequency (FB), and power output (PO) were monitored throughout the rides. Polynomial regression analyses showed VO2, RER, HR, and VE (correlation = −0.85 to −0.98) tracked the decreases in PO required to maintain a constant RPE. Only FB tracked RPE during the moderate and heavy intensity rides. Repeated measures ANOVAs indicated that VO2 during the 60 min rides at RPEGET was not different (p \u3e 0.05) from VO2 at GET from the incremental test to exhaustion. Thus, monitoring intensity using an RPE associated with the GET is sustainable for up to 60 min of cycling exercise and a common mechanism may mediate FB and the perception of effort during moderate and heavy intensity cycle ergometry

    A Synthesis on Digital Games in Education: What the Research Literature Says from 2000 to 2010

    Get PDF
    this research reports the results of a literature synthesis conducted on digital gaming in education research literature. seventy-three digital gaming research articles in education were identified through a systematic literature search and were coded across several relevant criteria. our research indicates trends and patterns from empirical studies on digital gaming in education from 2000 to 2010. Most research literature appears in the context of K-12 and higher education, and most literature appears to rely on experimental methods of research. the results show a steady increase in the number of publications related to digital gaming in education being published since 2004. the results also demonstrate that literature in digital gaming in education lacks completeness in reporting vital information, such as treatment intensity and duration, gaming platforms, or the number of players in a game. the missing information is vital in understanding the scope and direction of digital gaming research in education. recommendations for future research are provided. 26

    Black patients referred to a lung cancer screening program experience lower rates of screening and longer time to follow-up.

    Get PDF
    BACKGROUND: Racial disparities are well-documented in preventive cancer care, but they have not been fully explored in the context of lung cancer screening. We sought to explore racial differences in lung cancer screening outcomes within a lung cancer screening program (LCSP) at our urban academic medical center including differences in baseline low-dose computed tomography (LDCT) results, time to follow-up, adherence, as well as return to annual screening after additional imaging, loss to follow-up, and cancer diagnoses in patients with positive baseline scans. METHODS: A historical cohort study of patients referred to our LCSP was conducted to extract demographic and clinical characteristics, smoking history, and lung cancer screening outcomes. RESULTS: After referral to the LCSP, blacks had significantly lower odds of receiving LDCT compared to whites, even while controlling for individual lung cancer risk factors and neighborhood-level factors. Blacks also demonstrated a trend toward delayed follow-up, decreased adherence, and loss to follow-up across all Lung-RADS categories. CONCLUSIONS: Overall, lung cancer screening annual adherence rates were low, regardless of race, highlighting the need for increased patient education and outreach. Furthermore, the disparities in race we identified encourage further research with the purpose of creating culturally competent and inclusive LCSPs

    The effects of anatabine on non-invasive indicators of muscle damage: a randomized, double-blind, placebo-controlled, crossover study

    Get PDF
    Background: Anatabine (ANA), a minor tobacco alkaloid found in the Solanaceae family of plants, may exhibit anti-inflammatory activity, which may be useful to aid in recovery from exercise-induced muscle damage. The purpose of this study, therefore, was to examine the effects of ANA supplementation on the recovery of isometric strength and selected non-invasive indicators of muscle damage. Methods: A double-blinded, placebo-controlled, crossover design was used to study eighteen men (mean ± SD age = 22.2 ± 3.1 yrs; body mass = 80.3 ± 15.7 kg) who participated in two randomly-ordered conditions separated by a washout period. The ANA condition consisted of consuming 6–12 mg anatabine per day for 10 days, while testing took place during days 7–10. The placebo (PLA) condition was identical except that the PLA supplement contained no ANA. Maximal voluntary isometric peak torque (PT) of the forearm flexors, arm circumference, hanging joint angle, and subjective pain ratings were measured before (PRE), immediately after (POST), and 24, 48, and 72 h after six sets of 10 maximal, eccentric isokinetic forearm flexion muscle actions. Resting heart rate and blood pressure were measured at PRE and 72 h in each condition. Results: For PT, hanging joint angle, arm circumference, and subjective pain ratings, there were no condition x time (p \u3e 0.05) interactions, there were no main effects for condition (p \u3e 0.05), but there were main effects for time (p \u3c 0.001). There were no condition x time (p \u3e 0.05) interactions and no main effects for condition (p \u3e 0.05) or time (p \u3e 0.05) for blood pressure or resting heart rate. Conclusions: ANA supplementation had no effect on the recovery of muscle strength, hanging joint angle, arm swelling, or subjective pain ratings after a bout of maximal eccentric exercise in the forearm flexors. Therefore, ANA may not be beneficial for those seeking to improve recovery from heavy eccentric exercise. Future studies should examine the effects of ANA on the pro-inflammatory cytokine responses to exercise-induced muscle damage and the chronic low-grade inflammation observed in obese and elderly individuals

    Treaty of Fort Laramie, 1868 (Kappler)

    Get PDF
    This 1904 reprint of the Sioux Treaty of 1868, also known as the Treaty of Fort Laramie, 1868, was transcribed and published in vol. II of Charles Kappler’s Indian Affairs. Laws and Treaties. This treaty, between the United States government and the Sioux and Arapaho Nations, established the Great Sioux Reservation, promised the Sioux would own the Black Hills in perpetuity, and set aside the country north of the North Platte River and east of the summits of the Big Horn Mountains as unceded Indian territory. Furthermore, the U.S. government pledged to close the Bozeman Trail forts and provide food, clothing, and annuities to the tribes, given that they agreed to relinquish all rights to live outside the reservation.https://commons.und.edu/indigenous-gov-docs/1176/thumbnail.jp
    • …
    corecore