bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geomorphological significance of at‐many‐stations hydraulic geometry
Authors: Shen Chaopeng , Wang Shilong , Liu Xiaofeng 
Published: April 2016

AbstractThe critically important at‐a‐station hydraulic geometry (AHG) relationships relate hydraulic variables (depth, width, or velocity) to discharge in power law form. The recently discovered at‐many‐stations hydraulic geometry (AMHG) states that AHG exponents and coefficients are strongly correlated, removing one parameter and lending AMHGs to remote sensing discharge estimation. Despite the excitement, there is an urgent need to clarify AMHG's geomorphological significance for different hydraulic variables. Using data from 57 rivers in the U.S. and perturbation experiments, we show that the width‐AMHG is weak, arising mainly from the mathematical construct involving the exponent in both the regressor and the regressand. In contrast, the depth‐AMHGs result from geomorphological coevolution. The similar‐time‐mean condition, as argued for in the literature, is sufficient but not necessary for rating curve convergence and in turn AMHG, for depth and velocity. The predictive accuracy of AMHGs, whose coefficient of determination is unit dependent, is similar to the flow percentile‐based downstream hydraulic geometry.
What causes the inverse relationship between primary production and export efficiency in the Southern Ocean?
Authors: Le Moigne Frédéric A. C. , Henson Stephanie A. , Cavan Emma , Georges Clément , Pabortsava Katsiaryna , Achterberg Eric P. , Ceballos‐Romero Elena , Zubkov Mike , Sanders Richard J. 
Published: April 2016

AbstractThe ocean contributes to regulating atmospheric CO2 levels, partly via variability in the fraction of primary production (PP) which is exported out of the surface layer (i.e., the e ratio). Southern Ocean studies have found that contrary to global‐scale analyses, an inverse relationship exists between e ratio and PP. This relationship remains unexplained, with potential hypotheses being (i) large export of dissolved organic carbon (DOC) in high PP areas, (ii) strong surface microbial recycling in high PP regions, and/or (iii) grazing‐mediated export that varies inversely with PP. We find that the export of DOC has a limited influence in setting the negative e ratio/PP relationship. However, we observed that at sites with low PP and high e ratios, zooplankton‐mediated export is large and surface microbial abundance low suggesting that both are important drivers of the magnitude of the e ratio in the Southern Ocean.
The contribution of ozone to future stratospheric temperature trends
Authors: Maycock A. C. 
Published: April 2016

AbstractThe projected recovery of ozone from the effects of ozone depleting substances this century will modulate the stratospheric cooling due to CO2, thereby affecting the detection and attribution of stratospheric temperature trends. Here the impact of future ozone changes on stratospheric temperatures is quantified for three representative concentration pathways (RCPs) using simulations from the Fifth Coupled Model Intercomparison Project (CMIP5). For models with interactive chemistry, ozone trends offset ~50% of the global annual mean upper stratospheric cooling due to CO2 for RCP4.5 and 20% for RCP8.5 between 2006–2015 and 2090–2099. For RCP2.6, ozone trends cause a net warming of the upper and lower stratosphere. The misspecification of ozone trends for RCP2.6/RCP4.5 in models that used the International Global Atmospheric Chemistry (IGAC)/Stratosphere‐troposphere Processes and their Role in Climate (SPARC) Ozone Database causes anomalous warming (cooling) of the upper (lower) stratosphere compared to chemistry‐climate models. The dependence of ozone chemistry on greenhouse gas concentrations should therefore be better represented in CMIP6.
Primordial metallic melt in the deep mantle
Authors: Zhang Zhou , Dorfman Susannah M. , Labidi Jabrane , Zhang Shuai , Li Mingming , Manga Michael , Stixrude Lars , McDonough William F. , Williams Quentin 
Published: April 2016

AbstractSeismic tomography models reveal two large low shear velocity provinces (LLSVPs) that identify large‐scale variations in temperature and composition in the deep mantle. Other characteristics include elevated density, elevated bulk sound speed, and sharp boundaries. We show that properties of LLSVPs can be explained by the presence of small quantities (0.3–3%) of suspended, dense Fe‐Ni‐S liquid. Trapping of metallic liquid is demonstrated to be likely during the crystallization of a dense basal magma ocean, and retention of such melts is consistent with currently available experimental constraints. Calculated seismic velocities and densities of lower mantle material containing low‐abundance metallic liquids match the observed LLSVP properties. Small quantities of metallic liquids trapped at depth provide a natural explanation for primitive noble gas signatures in plume‐related magmas. Our model hence provides a mechanism for generating large‐scale chemical heterogeneities in Earth's early history and makes clear predictions for future tests of our hypothesis.
Formation of Alfvénic resonance layers in magnetic reconnection
Authors: Li L. J. , Tian L. P. , Ma Z. W. 
Published: April 2016

AbstractIn the framework of two‐dimensional incompressible MHD, we investigate the formation of Alfvénic resonance layers with different super‐Alfvénic shear flows. It is found that Alfvénic resonance layers are formed in the inflow region for the cases with the shear flow thickness larger than the current sheet thickness. The Alfvénic layers exist at where the flow velocity is equal to the local Alfvén speed and slowly drift away from the current sheet region as a magnetic island develops. The ratio (D) between the separation of the Alfvénic resonance layers and the current sheet thickness plays a crucial role on magnetic reconnection. It is found that D ~ 3 is a critical value, which is about the saturated size of a magnetic island in magnetic reconnection without super‐Alfvénic shear flow. For D < 3, the super‐Alfvénic shear flow shows mainly a suppressing effect on magnetic reconnection and the peaked reconnection rate drops below the rate without a super‐Alfvénic shear flow. When D > 3, the boosting effect of Kelvin‐Helmholtz instability surpasses the suppressing effect by Alfvénic resonance and the peaked reconnection rate is larger than that without a super‐Alfvénic shear flow. For D ~ 5, the super‐Alfvénic shear flow gives rise to a strongest boosting effect on magnetic reconnection. Possible applications are briefly discussed.
A theoretical investigation on the parametric instability excited by X‐mode polarized electromagnetic wave at Tromsø
Authors: Wang Xiang , Cannon Patrick , Zhou Chen , Honary Farideh , Ni Binbin , Zhao Zhengyu 
Published: April 2016

AbstractRecent ionospheric modification experiments performed at Tromsø, Norway, have indicated that X‐mode pump wave is capable of stimulating high‐frequency enhanced plasma lines, which manifests the excitation of parametric instability. This paper investigates theoretically how the observation can be explained by the excitation of parametric instability driven by X‐mode pump wave. The threshold of the parametric instability has been calculated for several recent experimental observations at Tromsø, illustrating that our derived equations for the excitation of parametric instability for X‐mode heating can explain the experimental observations. According to our theoretical calculation, a minimum fraction of pump wave electric field needs to be directed along the geomagnetic field direction in order for the parametric instability threshold to be met. A full‐wave finite difference time domain simulation has been performed to demonstrate that a small parallel component of pump wave electric field can be achieved during X‐mode heating in the presence of inhomogeneous plasma.
Empirical predictive models of daily relativistic electron flux at geostationary orbit: Multiple regression analysis
Authors: Simms Laura E. , Engebretson Mark J. , Pilipenko Viacheslav , Reeves Geoffrey D. , Clilverd Mark 
Published: April 2016

AbstractThe daily maximum relativistic electron flux at geostationary orbit can be predicted well with a set of daily averaged predictor variables including previous day's flux, seed electron flux, solar wind velocity and number density, AE index, IMF Bz, Dst, and ULF and VLF wave power. As predictor variables are intercorrelated, we used multiple regression analyses to determine which are the most predictive of flux when other variables are controlled. Empirical models produced from regressions of flux on measured predictors from 1 day previous were reasonably effective at predicting novel observations. Adding previous flux to the parameter set improves the prediction of the peak of the increases but delays its anticipation of an event. Previous day's solar wind number density and velocity, AE index, and ULF wave activity are the most significant explanatory variables; however, the AE index, measuring substorm processes, shows a negative correlation with flux when other parameters are controlled. This may be due to the triggering of electromagnetic ion cyclotron waves by substorms that cause electron precipitation. VLF waves show lower, but significant, influence. The combined effect of ULF and VLF waves shows a synergistic interaction, where each increases the influence of the other on flux enhancement. Correlations between observations and predictions for this 1 day lag model ranged from 0.71 to 0.89 (average: 0.78). A path analysis of correlations between predictors suggests that solar wind and IMF parameters affect flux through intermediate processes such as ring current (Dst), AE, and wave activity.
Solar activity variability in the IRI at high latitudes: Comparisons with GPS total electron content
Authors: Themens David R. , Jayachandran P. T. 
Published: April 2016

AbstractTotal electron content (TEC) measurements from 10 dual‐frequency GPS receivers in the Canadian High Arctic Ionospheric Network (CHAIN) are used to evaluate the performance of International Reference Ionosphere (IRI)‐2007 within the Canadian sector. Throughout the region, we see systematic underestimation of daytime TEC, particularly at solar maximum, where summer and equinox root‐mean‐square errors reach as high as 14 total electron content units, 1 TECU = 1016 el m−2 (TECU). It is also shown that the use of a monthly IG index, in place of the IRI's standard IG12 index, leads to an improvement in TEC specification by up to 3 TECU in the polar cap and up to 6 TECU in the subauroral region during periods of short‐term, large amplitude changes in solar activity. On diurnal timescales, variability in TEC is found to be underestimated by the IRI, during equinox periods, by up to 40% at subauroral latitudes and up to 70% in the polar cap region. During the winter, diurnal variations are overestimated by up to 40% in the subauroral region and are underestimated within the polar cap by up to 80%. Using collocated ionosonde data, we find IRI bottomside TEC to be within 1 TECU of observation with errors largest during the equinoxes. For the topside we find good agreement during the winter but significant underestimation of topside TEC by the IRI during summer and equinox periods, exceeding 6 TECU at times. By ingesting measured NmF2 into the IRI, we show that the topside thickness parameterization is the source of the bulk of the observed TEC errors.
Major variations in subtropical North Atlantic heat transport at short (5 day) timescales and their causes
Authors: Moat B. I. , Josey S. A. , Sinha B. , Blaker A. T. , Smeed D. A. , McCarthy G. D. , Johns W. E. , Hirschi J. J.‐M. , Frajka‐Williams E. , Rayner D. , Duchez A. , Coward A. C. 
Published: April 2016

AbstractVariability in the North Atlantic ocean heat transport at 26.5°N on short (5 day) timescales is identified and contrasted with different behaviour at monthly intervals using a combination of RAPID/MOCHA/WBTS measurements and the NEMO‐LIM2 1/12° ocean circulation/sea ice model. Wind forcing plays the leading role in establishing the heat transport variability through the Ekman transport response of the ocean and the associated driving atmospheric conditions vary significantly with timescale. We find that at 5 day timescales the largest changes in the heat transport across 26.5°N coincide with north‐westerly airflows originating over the American land mass that drive strong southward anomalies in the Ekman flow. During these events the northward heat transport reduces by 0.5–1.4 PW. In contrast, the Ekman transport response at longer monthly timescales is smaller in magnitude (up to 0.5 PW) and consistent with expected variations in the leading mode of North Atlantic atmospheric variability, the North Atlantic Oscillation. The north‐westerly airflow mechanism can have a prolonged influence beyond the central 5 day timescale and on occasion can reduce the accumulated winter ocean heat transport into the North Atlantic by ∼40%.
Radiocarbon‐derived source apportionment of fine carbonaceous aerosols before, during, and after the 2014 Asia‐Pacific Economic Cooperation (APEC) summit in Beijing, China
Authors: Liu Junwen , Mo Yangzhi , Li Jun , Liu Di , Shen Chengde , Ding Ping , Jiang Haoyu , Cheng Zhineng , Zhang Xiangyun , Tian Chongguo , Chen Yingjun , Zhang Gan 
Published: April 2016

AbstractThe Asia‐Pacific Economic Cooperation (APEC) summit took place in Beijing, China, 5–11 November 2014, during which numerous measures were performed to control the air pollution, and consequently, the sky of Beijing was so clean that the public called it “APEC blue.” The concentrations before, during, and after the APEC summit are 14.4 ± 6.81 µg C/m3, 6.66 ± 2.99 µg C/m3, and 32.3 ± 10.6 µg C/m3, respectively, for organic carbon (OC), and 2.27 ± 1.17 µg C/m3, 0.76 ± 0.52 µg C/m3, and 4.99 ± 1.74 µg C/m3, respectively, for elemental carbon (EC). We quantify the contributions of fossil and nonfossil sources to the OC and EC using radiocarbon. Results show that the contribution of nonfossil sources is 56 ± 1% (before APEC), 61 ± 1% (during APEC), and 48 ± 1% (after APEC), respectively, for OC, and 36 ± 4% (before APEC), 46 ± 1% (during APEC), and 33 ± 4% (after APEC), respectively, for EC. Comparing to the period before APEC, 70% and 60% of fossil EC and OC and 60% and 50% of nonfossil EC and OC are reduced, respectively, implying that the control on the nonfossil sources has considerable contribution to the good air quality in Beijing. Both EC and OC mass loadings during the APEC summit would have increased by 60% if the biomass‐burning activities were not taken into account for control. In such a case, the atmospheric visibility would decrease 20% at least and the blue sky thereby would likely not have been visible during the summit.
Cost‐Effectiveness Analysis of First‐Line Treatment With Biologic Agents in Polyarticular Juvenile Idiopathic Arthritis
Authors: Luca Nadia J. , Burnett Heather F. , Ungar Wendy J. , Moretti Myla E. , Beukelman Timothy , Feldman Brian M. , Schwartz Gwen , Bayoumi Ahmed M. 
Published: April 2016

ObjectiveThe optimal timing of biologic agent treatment in polyarticular juvenile idiopathic arthritis (JIA) is unknown. This study evaluated the costs and outcomes of first‐line treatment with etanercept (ETN), an anti–tumor necrosis factor (anti‐TNF) agent, compared with step‐wise therapy in JIA.MethodsWe compared 2 strategies: methotrexate (MTX) plus ETN as first‐line therapy (ETN‐first) and MTX monotherapy followed by ETN (ETN‐second), using a cohort state‐transition model of newly diagnosed JIA patients. The model's time horizon was 5 years, and the perspective was that of the Canadian health care system. The base case patient was 11 years old, weighed 40 kg, and had 5 or more active joints. Direct costs were calculated and discounted at a rate of 3% per year. Outcomes were expressed as quality‐adjusted life years (QALYs). Scenario analyses varied multiple parameters simultaneously to model more severely and more mildly affected patients.ResultsETN‐first, compared to ETN‐second, yielded a discounted incremental cost of $16,893 (95% confidence interval [95% CI] 9,348–25,310), incremental QALY of 0.19 (95% CI 0.08–0.32), and an incremental cost‐effectiveness ratio of $88,815 per QALY gained. The results were sensitive to the cost of ETN, the time horizon of the model, and estimates of the efficacy of the first‐line therapies. The cost per QALY for treating patients with severe JIA was $33,960.ConclusionFirst‐line therapy of ETN and MTX is relatively expensive compared to MTX alone, but may be economically attractive for more severely affected patients. More research is needed regarding the efficacy of first‐line anti‐TNF agents.
Social Role Participation in Patients With Ankylosing Spondylitis: A Cross‐Sectional Comparison With Population Controls
Authors: van Genderen Simon , Plasqui Guy , Landewé Robert , Lacaille Diane , Arends Suzanne , van Gaalen Floris , van der Heijde Désirée , Heuft Liesbeth , Luime Jolanda , Spoorenberg Anneke , Gignac Monique , Boonen Annelies 
Published: April 2016

ObjectiveParticipation in social roles for persons with chronic disease is important for their quality of life, but interpretation of the data on participation is difficult in the absence of a benchmark. This study aimed to compare social role participation in patients with ankylosing spondylitis (AS) to population controls using the Social Role Participation Questionnaire (SRPQ).MethodsThere were 246 AS patients and 510 population controls who completed the SRPQ, which assesses participation in 11 roles (with scores ranging 1–5) across 4 dimensions (importance, satisfaction with performance, satisfaction with time, and physical difficulty), and additionally ranked their 3 most important roles. The ranking of role importance, the SRPQ dimension scores, and the gap between importance and satisfaction with performance of roles were compared between patients and controls.ResultsPatients (62% male; mean ± SD age 51 ± 12 years) and controls (70% male; mean ± SD 42 ± 15 years) ranked intimate relationships, relationships with children/stepchildren/grandchildren, and employment as the most important roles. Compared to controls, patients gave higher scores on the SRPQ to importance (3.75 versus 3.43), but reported lower satisfaction with performance (3.19 versus 3.58) and greater physical difficulty (3.87 versus 4.67) (P ≤ 0.05 for all). The largest differences in gaps between importance and satisfaction with performance for patients compared to controls were seen in the physical leisure, hobbies, and traveling and vacation categories, in which patients assigned higher importance but reported especially low satisfaction.ConclusionAs society places increasing emphasis on individual responsibility to participate fully in social roles, the current data suggest that health care providers should pay more attention to participation restrictions experienced by patients with AS.
Accumulation of Risk and Promotive Factors Among Young Children in US Military Families
Authors: Wadsworth Shelley MacDermid , Cardin Jean‐Francois , Christ Sharon , Willerton Elaine , O'Grady Allison Flittner , Topp David , Coppola Elizabeth , Lester Patricia , Mustillo Sarah 
Published: April 2016

AbstractIn the families of the new cohort of war veterans now entering the civilian population in the United States are over two million young children (Cozza, Haskins & Lerner, 2013; Institute of Medicine, 2013). Several noteworthy studies have shown that children exposed to separation from a parent due to combat‐related deployment are at elevated risk for a variety of negative consequences (Lester & Flake, 2013). Cozza et al. (2013) argue that existing studies of military children focus too much on the stresses or deficits they experience, failing to give sufficient attention to their strengths, the strengths of their families, or the supports around them. In the current study we focus on risk and promotive factors in the lives of children aged 0–10 in military families. We examine the likelihood of negative outcomes as functions of additive, cumulative, and interactive relationships between risk and promotive factors and children's outcomes. Risk factors, particularly parental depression, community poverty, and cumulative risk, were more strongly associated with children's outcomes than promotive factors. There was, however, a significant risk‐protective relationship between accumulations of risk and promotive factors, consistent with promotive conditions operating in a protective fashion under conditions of elevated risk.
Clinical Community Psychology: Reflections on the Decades Following Swampscott
Authors: A. Jenkins Richard 
Published: April 2016

AbstractThe Swampscott report was foundational, but in some ways reflected divisions within community psychology that have continued into the present. Community psychologists trained in the 1970s and, especially, the 1980s confronted a period where the original focus of community mental health began to have less influence in the mental health field due to a variety of public policies, and the growth of third party payments as a significant source of health care funding. Programs that engaged communities and provided a base for prevention interventions were greatly curtailed because of changes in federal legislation and limited opportunities for state and local funding, although prevention interventions found growing interest from research funders. Clinical and community psychologists who trained in this period increasingly looked to a variety of areas outside of mental health. Consequently, the field of community psychology has become more applied and less academic, with increased attention to advocacy, theory, and global perspectives. The sweep of these changes and their implications for the future of the field are discussed here.
Stable isotope study on ancient populations of central sudan: Insights on their diet and environment
Authors: Iacumin Paola , Di Matteo Antonietta , Usai Donatella , Salvatori Sandro , Venturelli Giampiero 
Published: April 2016

ABSTRACTObjectivesA contribution to the knowledge of the economy and the environmental surroundings of the populations living along the Nile valley in three different periods.Materials and methodsThis study reports stable isotope analyses on apatite bone samples of 139 humans, 48 mammals, and 43 fish from the Al Khiday archaeological sites in Sudan. The bones belong to four archaeological periods: pre‐Mesolithic, Mesolithic, Neolithic, and Meroitic. Data were processed statistically.ResultsA significant difference exists between the pre‐Mesolithic and Mesolithic mean δ18Ow value and the mean of the modern Nile. The mean δ18Ow values for the Neolithic humans and bovids are very similar (+1.5‰ ±4‰, and −2‰, respectively) and more positive than the mean values of Mesolithic mammals and Pre‐Mesolithic humans. The water ingested by Meroitic humans (+7‰ ± 2.5‰) is enriched in 18O in respect to the water ingested by the Neolithic population. There is a separation in the δ13Cdiet values between the pre‐Mesolithic humans (−14‰ ± 1‰) and Mesolithic mammals (−12‰ ± 2‰) group and the Neolithic humans (−18‰ ± 1‰), Meroitic humans (−19‰ ±1‰), Neolithic mammals (−21‰), and the modern (mean δ13Cdiet = −19‰ ±2‰) mammal group.DiscussionThe climate became warmer and more arid from the pre‐Mesolithic/Mesolithic to the Meroitic period. The environmental conditions influenced the strategies of subsistence and, in particular, the changes occurring from the pre‐Mesolithic to the Neolithic can be considered contemporaneous to the transition from hunting‐gathering‐fishing to cultivation‐herding. Am J Phys Anthropol 160:498–518, 2016. © 2016 Wiley Periodicals, Inc.