bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of climate change on the potential forest productivity based on a climate-driven biophysical model in northeastern China
Authors: Gao Wen-Qiang , Lei Xiang-Dong , Fu Li-Yong
Published: June 2019

Climate warming is expected to influence forest growth, composition and distribution. However, accurately estimating and predicting forest biomass, potential productivity or forest growth is still a challenge for forest managers dealing with land-use at the stand to regional levels. In the present study, we predicted the potential productivity (PP) of forest under current and future climate scenarios (RCP2.6, RCP4.5, RCP6.0 and RCP8.5) in Jilin province, northeastern China by using Paterson’s Climate Vegetation and Productivity (CVP) index model. The PP was validated by comparing it with the mean and maximum net primary production calculated from light energy utilization (GLM_PEM). Our results indicated that using the CVP index model is partially valid for predicting the potential forest productivity in northeastern China. PP exhibited obvious spatial heterogeneity varying from 4.6 to 8.9 m3 ha−1 year−1with an increasing tendency from northwest to southeast driven by the precipitation across the region. The number of vegetation-active months, precipitation and insolation coefficient were identified as the primary factors affecting PP, but no significant relationship was found for warmest temperature or temperature fluctuation. Under future climate scenarios, PP across the Jilin Province is expected to increase from 1.38% (RCP2.6 in 2050) to 15.30% (RCP8.5 in 2070), especially in the eastern Songnen Plain (SE) for the RCP8.5 scenarios.
A 24‐week double‐blind placebo‐controlled study of the efficacy and safety of the AMPA modulator S47445 in patients with mild to moderate Alzheimer's disease and depressive symptoms
Authors: Bernard Katy , Gouttefangeas Sylvie , Bretin Sylvie , Galtier Stéphanie , Robert Philippe , Holthoff‐Detto Vjera , Cummings Jeffrey , Pueyo Maria
Published: June 2019

Introduction

S47445 is a novel positive allosteric modulator of alpha‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazole‐propionic acid receptors that may emerge as a favorable candidate for the symptomatic treatment of cognitive and depressive disorders in patients suffering from Alzheimer's disease (AD) of mild to moderate severity and with depressive symptoms.

Methods

For this double‐blind, placebo‐controlled 24‐week phase II trial, 520 outpatients aged between 55 and 85 years, with probable AD at mild to moderate stages (a Mini‐Mental State Examination score of 24‐15 inclusive) and exhibiting depressive symptoms (Cornell Scale for Depression in Dementia [CSDD] ≥ 8) were recruited in twelve countries and randomized to 3 doses of S47445 (5‐15‐50 mg) or placebo. The primary end point was the change from baseline in the 11‐item Alzheimer's Disease Assessment Scale‐Cognitive subscale (ADAS‐Cog) total score at week 24. Secondary measures included the Disability Assessment for Dementia, Mini‐Mental State Examination, ADAS‐Cog 13‐item, CSDD, Clinical Global Impression of Change (Alzheimer's Disease Cooperative Study‐CGIC), Neuropsychiatric Inventory (NPI), and safety criteria.

Results

Baseline characteristics were comparable between the 4 groups. After 24 weeks, no statistically significant treatment difference was demonstrated between S47445 (5, 15 or 50 mg/d) and placebo on cognition (ADAS‐Cog), function (Disability Assessment for Dementia), or depressive symptoms (CSDD). An improvement on neuropsychiatric symptoms assessed by NPI was evidenced at the lower dose 5 mg/d (Δ ‐2.55, P = .023, post hoc analysis) compared to placebo. CSDD and total NPI scores improved in all groups including placebo. There were no specific and/or unexpected safety signals observed with any of the S47445 doses.

Discussion

S47445 administered for 24 weeks was safe and well tolerated by patients with mild to moderate AD; the compound did not show significant benefits over placebo on cognition, function, or depressive symptoms.
Life and Mind: Varieties of Neo-Aristotelianism: Naive, Sophisticated, Hegelian
Authors: Kern Andrea
Published: June 2019

In his treatment of subjective mind, Hegel argues that the development that characterizes the vital process of a human individual is logically unique in that it dissolves the contradiction between two logical determinations that characterize any vital activity: the contradiction between the ‘immediate singularity’ of the subject of this process and its ‘abstract generality’. Hegel employs the term Bildung to characterize any vital activity that has this form. The idea that the distinction between human life and non-human life is a logical distinction is one of the main lessons that Hegel thinks we should learn from Aristotle's treatment of the idea of life. In this article I distinguish between two contemporary varieties of this Aristotelian idea: a sophisticated variety that emphasizes the idea of second nature in order to characterize the distinctiveness of the human, and a naive variety that thinks of the human's uniqueness in terms of characterizations that already belong to its first nature. I argue that Hegel is neither sophisticated nor naive but offers a third variety of Neo-Aristotelianism that solves the difficulties of the other two. This has decisive consequences for his understanding of Bildung. Although the notion of Bildung describes an empirical process, Hegel argues, it is not an empirical concept. Rather, it is the concrete concept of the process of actualization that characterizes a self-conscious form of life that reflects the inner temporality of this form's actuality.
Direct numerical simulations of Taylor–Couette turbulence: the effects of sand grain roughness
Authors: Berghout Pieter , Zhu Xiaojue , Chung Daniel , Verzicco Roberto , Stevens Richard J. A. M. , Lohse Detlef
Published: June 2019

Progress in roughness research, mapping any given roughness geometry to its fluid dynamic behaviour, has been hampered by the lack of accurate and direct measurements of skin-friction drag, especially in open systems. The Taylor–Couette (TC) system has the benefit of being a closed system, but its potential for characterizing irregular, realistic, three-dimensional (3-D) roughness has not been previously considered in depth. Here, we present direct numerical simulations (DNSs) of TC turbulence with sand grain roughness mounted on the inner cylinder. The model proposed by Scotti (Phys. Fluids, vol. 18, 031701, 2006) has been modified to simulate a random rough surface of monodisperse sand grains. Taylor numbers range from $Ta=1.0\times 10^{7}$(corresponding to $Re_{\unicode[STIX]{x1D70F}}=82$) to $Ta=1.0\times 10^{9}$ ($Re_{\unicode[STIX]{x1D70F}}=635$). We focus on the influence of the roughness height $k_{s}^{+}$ in the transitionally rough regime, through simulations of TC with rough surfaces, ranging from $k_{s}^{+}=5$ up to $k_{s}^{+}=92$. We analyse the global response of the system, expressed both by the dimensionless angular velocity transport $Nu_{\unicode[STIX]{x1D714}}$ and by the friction factor $C_{f}$. An increase in friction with increasing roughness height is accompanied with enhanced plume ejection from the inner cylinder. Subsequently, we investigate the local response of the fluid flow over the rough surface. The equivalent sand grain roughness $k_{s}^{+}$ is calculated to be $1.33k$, where $k$ is the size of the sand grains. We find that the downwards shift of the logarithmic layer, due to transitionally rough sand grains exhibits remarkably similar behaviour to that of the Nikuradse (VDI-Forsch., vol. 361, 1933) data of sand grain roughness in pipe flow, regardless of the Taylor number dependent constants of the logarithmic layer. Furthermore, we find that the dynamical effects of the sand grains are contained to the roughness sublayer $h_{r}$ with $h_{r}=2.78k_{s}$.
Bubble and conical forms of vortex breakdown in swirling jets
Authors: Moise Pradeep , Mathew Joseph
Published: June 2019

Experimental investigations of laminar swirling jets had revealed a new form of vortex breakdown, named conical vortex breakdown, in addition to the commonly observed bubble form. The present study explores these breakdown states that develop for the Maxworthy profile (a model of swirling jets) at inflow, from streamwise-invariant initial conditions, with direct numerical simulations. For a constant Reynolds number based on jet radius and a centreline velocity of 200, various flow states were observed as the inflow profile’s swirl parameter $S$ (scaled centreline radial derivative of azimuthal velocity) was varied up to 2. At low swirl ($S=1$) a helical mode of azimuthal wavenumber $m=-2$ (co-winding, counter-rotating mode) was observed. A ‘swelling’ appeared at $S=1.38$, and a steady bubble breakdown at $S=1.4$. On further increase to $S=1.5$, a helical, self-excited global mode ($m=+1$, counter-winding and co-rotating) was observed, originating in the bubble’s wake but with little effect on the bubble itself – a bubble vortex breakdown with a spiral tail. Local and global stability analyses revealed this to arise from a linear instability mechanism, distinct from that for the spiral breakdown which has been studied using Grabowski profile (a model of wing-tip vortices). At still higher swirl ($S=1.55$), a pulsating type of bubble breakdown occurred, followed by conical breakdown at 1.6. The latter consists of a large toroidal vortex confined by a radially expanding conical sheet, and a weaker vortex core downstream. For the highest swirls, the sheet was no longer conical, but curved away from the axis as a wide-open breakdown. The applicability of two classical inviscid theories for vortex breakdown – transition to a conjugate state, and the dominance of negative azimuthal vorticity – was assessed for the conical form. As required by the former, the flow transitioned from a supercritical to subcritical state in the vicinity of the stagnation point. The deviations from the predictions of the latter model were considerable.
Convection regimes induced by local boundary heating in a liquid–gas system
Authors: Bekezhanova Victoria B. , Ovcharova A. S.
Published: June 2019

In the framework of the complete formulation of the conjugate problem, the liquid–gas flow structure arising upon local heating using thermal sources is investigated numerically. The two-layer system is confined by solid impermeable walls. The Navier–Stokes equations in the Boussinesq approximation in the ‘streamfunction–vorticity’ variables are used to describe the media motion. The dynamic conditions at the interface are formulated in terms of the tangential and normal velocities, while the temperature conditions at the external boundaries of the system take into account the presence of local heaters. The influence of the number of heaters and heating modes on the dynamics and character of the appearing convective regimes is analysed. The steady and commutated heating modes for one and two heaters arranged at the lower boundary are investigated. The heating initiates convective and thermocapillary mechanisms causing the fluid motion. Transient regimes with the successive formation of two-vortex, quadruple-vortex and two-vortex flows are observed before the stabilization of the system in the uniform heating mode. A stable thermocapillary deflection appears at the interface above the heater. The commutated mode of heating entails oscillations of the interface with a change in the deflection form and the formation of travelling vortices in the fluids. The impact of particular mechanisms on the flow patterns is analysed. The paper presents typical distributions of the velocity and temperature fields in the system and the position of the interface for the considered cases.
Assessment and Development of Bone Preparation for Radiocarbon Dating at HEKAL
Authors: Major István , Futó István , Dani János , Cserpák-Laczi Orsolya , Gasparik Mihály , Jull A J Timothy , Molnár Mihály
Published: June 2019

Bone is one of the most complex sample materials used for radiocarbon (14C) dating. The installation of the EnvironMICADAS AMS at HEKAL (department of ICER) in 2011 required the adoption of new sample preparation techniques for small bone samples. Since then, hundreds of procedural background and known-age bones have been processed using our modified Longin method (MLM) and dated along with unknown samples. Their results are used in this study to assess the reproducibility of our current bone preparation method and the real uncertainty of the final age result. In addition, using the background samples, which are included in each bone measurement batch, blank correction of the unknown samples could also be performed. The mean F14C value of our bone blanks is generally better than 0.005 (∼42,500 BP) alongside 0.0013 SD. Good reproducibility was confirmed by the results of the laboratory known-age bone as well, where the standard deviation of the mean is better than 0.0025. In addition, the results of the three bone samples used in an ultrafiltration (UF) test study did not show notable differences from the ones obtained by our current protocol in 1σ uncertainty range but more experiments will be performed in the near future.
Association of the Dietary-Based Diabetes-Risk Score (DDS) with the risk of gestational diabetes mellitus in the Seguimiento Universidad de Navarra (SUN) project
Authors: Donazar-Ezcurra Mikel , Lopez-del Burgo Cristina , Martinez-Gonzalez Miguel A. , Dominguez Ligia J. , Basterra-Gortari Francisco J. , de Irala Jokin , Bes-Rastrollo Maira
Published: June 2019

It is crucial to identify people at risk for type 2 diabetes mellitus (T2DM) and gestational diabetes mellitus (GDM) to implement preventive interventions in order to address these pandemics. A simple score exclusively based on dietary components, the Dietary-Based Diabetes-Risk Score (DDS) showed a strong inverse association with incident T2DM. The objective was to assess the association between DDS and the risk of GDM in a cohort of Spanish university graduates. The ‘Seguimiento Universidad de Navarra’ project is a prospective and dynamic cohort which included data of 3455 women who notified pregnancies between 1999 and 2012. The diagnosis of GDM is self-reported and further confirmed by physicians. A validated 136-item semi-quantitative FFQ was used to assess pre-gestational dietary habits. The development of the DDS was aimed to quantify the association between the adherence to this a priori dietary score and T2DM incidence. The score exclusively included dietary components (nine food groups with reported inverse associations with T2DM incidence and three food groups which reported direct associations with T2DM). Three categories of adherence to the DDS were assessed: low (11–24), intermediate (25–39) and high (40–60). The upper category showed an independent inverse association with the risk of incident GDM compared with the lowest category (multivariate-adjusted OR 0·48; 95 % CI 0·24, 0·99; P for linear trend: 0·01). Several sensitivity analyses supported the robustness of these results. These results reinforce the importance of pre-gestational dietary habits for reducing GDM and provide a brief tool to practically assess the relevant dietary habits in clinical practice.
Shell variations in the gastropod,Monodonta labio, in the North-western Pacific: the important role of temperature in the evolution process
Authors: Zhao Dan , Kong Ling-Feng , Sasaki Takenori , Li Qi
Published: June 2019

Molluscan shells showing phenotypic variations are ideal models for studying evolution and plasticity. In north-eastern Asia, genetic and morphological diversity of the gastropod,Monodonta labio, were assumed to be influenced by both palaeoclimatic changes and current ecological factors. In this study, we examined spatial variations in shell shape ofM. labiousing general measurement and geometric morphometric analysis. We also investigated whether shell shape variation is best explained by environmental gradients or by genetic structuring, based on our prior molecular phylogeographic study. Two common morphological forms were observed among Chinese populations and in the adjacent Asian areas. Both the analyses revealed separation patterns in morphological variations of shell shape among the clades and populations. Environmental modelling analysis showed a significant correlation between shape variations and local maximum temperatures of the warmest month, indicating the role of natural selection in the evolution of this species. Data obtained in this study, combined with the cytochrome oxidase subunit I (COI) molecular phylogenetic data from the prior study, showed that morphological variations inM. labiowere constrained by both local adaptation and phenotypic plasticity. We hypothesized that geographic separation by the Dongshan Landbridge was the first step towards its diversification, and that the temperature gradient between the East China Sea and South China Sea probably was the selective force driving the divergence of its morphological variations.
On the future of the giant South American river turtle Podocnemis expansa
Authors: Forero-Medina German , Ferrara Camila R. , Vogt Richard C. , Fagundes Camila K. , Balestra Rafael Antônio M. , Andrade Paulo C. M. , Lacava Roberto , Bernhard Rafael , Lipman Alison J. , Lenz Ana Julia , Ferrer Arnaldo , Calle Arsenio , Aponte Andres F. , Calle-Rendón Bayron R. , Santos Camilo Cássia , Perrone Elis , Miraña Esteban , Cunha Fabio A. G. , Loja Eva , Del Rio Jennifer , Vera Fernandez Jorge Luiz , Hermández Omar E. , Del Aguila Rafael , Pino Rafael , Cueva Ruben , Martinez Sindy , Diniz Bernardes Virgínia Campos , Sainz Lila , Horne Brian D.
Published: June 2019

There is a long history of exploitation of the South American river turtle Podocnemis expansa. Conservation efforts for this species started in the 1960s but best practices were not established, and population trends and the number of nesting females protected remained unknown. In 2014 we formed a working group to discuss conservation strategies and to compile population data across the species’ range. We analysed the spatial pattern of its abundance in relation to human and natural factors using multiple regression analyses. We found that > 85 conservation programmes are protecting 147,000 nesting females, primarily in Brazil. The top six sites harbour > 100,000 females and should be prioritized for conservation action. Abundance declines with latitude and we found no evidence of human pressure on current turtle abundance patterns. It is presently not possible to estimate the global population trend because the species is not monitored continuously across the Amazon basin. The number of females is increasing at some localities and decreasing at others. However, the current size of the protected population is well below the historical population size estimated from past levels of human consumption, which demonstrates the need for concerted global conservation action. The data and management recommendations compiled here provide the basis for a regional monitoring programme among South American countries.
Citizens’ Opinions About Basic Income Proposals Compared – A Conjoint Analysis of Finland and Switzerland
Authors: STADELMANN-STEFFEN ISABELLE , DERMONT CLAU
Published: June 2019

The basic income (BI) scheme is a fundamental reform of the welfare state that has recently gained widespread attention. Proposals for different variants of BI schemes have emerged to account for varying political and societal goals. This study investigates what citizens think about the idea of a BI, and to what extent citizens’ perceptions depend on the exact design of such a scheme and the context in which this policy is embedded. Empirically, we rely on conjoint experiments conducted in Finland and Switzerland – the two countries in which the introduction of a BI scheme has recently been discussed most intensely. We find that the level of public support for BI is higher in Finland than it is in Switzerland. Moreover, despite the contrasting designs of the BI proposals in the two countries, both Finnish and Swiss citizens tend to favor more generous schemes restricting non-nationals’ access to the provision.
The Garbage Problem: Corruption, Innovation, and Capacity in Four American Cities, 1890–1940
Authors: Strach Patricia , Sullivan Kathleen , Pérez-Chiqués Elizabeth
Published: June 2019

While American political development scholars tend to focus on national or state-level politics, late nineteenth-century cities provided the lion's share of services: clean water, paved and lighted streets, and sanitation. How did cities innovate and build municipal capacity to do these things? We answer this question by looking at municipal responses to the garbage problem. As cities grew and trash piled up in the 1890s, cities explored ways to effectively collect the garbage. A government requires not just resources, but also the ability to marshal those resources. Corruption could provide such abilities. Looking at four corrupt cities—Pittsburgh, Charleston, New Orleans, and St. Louis—we consider whether corruption, and what type of corruption, fostered innovation and capacity. We compare these corrupt cities with a shadow study of the reformist government of Columbus. We found the following: (1) The logic of corruption is the most important factor to explain why municipal governments chose particular garbage strategies. Corrupt regimes chose garbage collection and disposal strategies that would benefit themselves—but these varied depending on what type of corruption dominated a city. (2) Corruption sometimes promoted innovation and capacity, but at other times, corruption hindered them. For better or worse, cities ruled by corruption gained the capacity that these informal regimes held.
Intimate partner violence management and referral practices of primary care workers in a selected population in Turkey
Authors: Taskiran Aysegul Catak , Ozsahin Aysun , Edirne Tamer
Published: June 2019

Background:

Violence against women is a significant public health problem and primary care workers (PCWs) have a crucial role in managing violence against women. However, though intimate partner violence (IPV) is frequently seen in primary care, most cases remain unreported.

Aims:

This study aims to investigate family physicians’ (FPs’) and co-working midwifes/nurses’ (M/Ns’) explanations about their responses to women disclosing IPV and the reasons for their actions.

Methods:

We conducted a cross-sectional survey via a face-to-face administered questionnaire interview involving 266 PCWs in a selected area in Turkey. We questioned the reasoning behind inappropriate responses such as not examining the patient and document findings, not recording a code of violence, and not notifying the police in the case of a disclosure of IPV.

Results:

We surveyed 129 FPs and 137 M/Ns. We found that the disclosure of IPV in primary care is very high, but more than one-third of physicians and half of M/Ns respond inappropriately. Reasons for inappropriate response varied. The majority believed that the victim would continue to live with her batterer, making any report ineffective. Some expressed concern for the women’s and their own personal safety, citing an increase in assault cases by perpetrators in the last few years. Many indicated a lack of knowledge about management of violence cases.

Conclusion:

Multiple barriers challenge PCWs in helping abused women. Common behaviours, safety concerns, and a lack of knowledge seem to be the major barriers to responding appropriately to IPV. To address this issue appropriately, protective measures for both parties – PCWs and violence victims – need to be enacted and a supportive constitutional and societal organization is required. Screening and identification should lead to interventions that benefit the victims rather than harming them.
Partisan motivated reasoning and misinformation in the media: Is news from ideologically uncongenial sources more suspicious?
Authors: Clayton Katherine , Davis Jase , Hinckley Kristen , Horiuchi Yusaku
Published: June 2019

In recent years, concerns about misinformation in the media have skyrocketed. President Donald Trump has repeatedly claimed that various news outlets are disseminating ‘fake news’ for political purposes. But when the information contained in mainstream media news reports provides no clear clues about its truth value or any indication of a partisan slant, do people rely on the congeniality of the news outlet to judge whether the information is true or false? In a survey experiment, we presented partisans (Democrats and Republicans) and ideologues (liberals and conservatives) with a news article excerpt that varied by source shown (CNN, Fox News, or no source) and content (true or false information), and measured their perceived accuracy of the information contained in the article. Our results suggest that the participants do not blindly judge the content of articles based on the news source, regardless of their own partisanship and ideology. Contrary to prevailing views on the polarization and politicization of news outlets, as well as on voters' growing propensity to engage in ‘partisan motivated reasoning,’ source cues are not as important as the information itself for partisans on both sides of the aisle.
Preliminary Evaluation of GPM‐IMERG Rainfall Estimates Over Three Distinct Climate Zones With APHRODITE
Authors: Sunilkumar K. , Yatagai Akiyo , Masuda Minami
Published: June 2019

Evaluation of Global Precipitation Measurement‐Integrated Multi‐satellitE Retrieval for GPM (GPM‐IMERG) final precipitation product is performed over Japan, Nepal, and Philippines regions against further improved APHRODITE‐2 V1801R1 product. The evolution is carried out for nearly two consecutive years 2014–2015. Various qualitative and quantitative statistical indices such as mean bias, root‐mean‐square error, correlation coefficient, false alarming ratio, and probability of detection are considered to evaluate GPM‐IMERG precipitation estimates with APHRODITE‐2. Intraseasonal variability of two products is shown to explore the seasonal dependency of GPM‐IMERG performance. The performance of GPM‐IMERG research product with respect to rainfall intensity is shown by the cumulative probability distribution of target and reference data sets. Percentile‐based statistics is implemented for evaluating the advantages of GPM‐IMERG over Tropical Rainfall Measuring Mission‐3B42 while detecting the light and heavy rainfall events during wet/dry seasons. The overall performance of GPM‐IMERG seems to be good over Japan followed by Philippines and Nepal regions. This feature is clearly evidenced in terms of mean bias, root‐mean‐square error, and correlation magnitudes over three regions. GPM‐IMERG shows ability to follow the intraseasonal variability as shown by APHRODITE‐2 product with minor differences observed in precipitation maximum values during rainy season. Good agreement is seen between GPM‐IMERG and APHRODITE‐2 at different rainfall intensities except underestimation during heavy rainfall events. GPM‐IMERG seems to be improved in detecting light/heavy rainfall event magnitude than TRM‐3B42. However, the performance of both data sets encountered clear dependency on seasons.
Quasiperiodic ELF/VLF Emissions Detected Onboard the DEMETER Spacecraft: Theoretical Analysis and Comparison With Observations
Authors: Pasmanik D. L. , Demekhov A. G. , Hayoš M. , Němec F. , Santolík O. , Parrot M.
Published: June 2019

We present results of numerical simulation of quasiperiodic (QP) extra low frequency/very low frequency emissions performed by using a theoretical model of flow cyclotron maser based on a self‐consistent set of equations of the quasi‐linear plasma theory averaged over oscillations of waves and particles in a geomagnetic flux tube. Calculations were made for a wide range of plasma parameters (i.e., cold plasma density, L‐shell, and energetic electron flux) in order to obtain a statistical relationship between various properties of QP emissions, such as the repetition period, the frequency bandwidth, the frequency drift rate, and the characteristic wave spectral energy density. The theoretical results are compared with the results of a statistical study of QP emissions measured by the DEMETER spacecraft (Hayosh et al., 2014, https://doi.org/10.1002/2013JA019731). The simulation results are in a good agreement with the observation data in the case of reasonable choice of cold plasma density value and its dependence on the QP‐source location (L‐shell). In particular, an increase in the frequency bandwidth of QP very low frequency waves with increasing central frequency of QP emissions, a decrease in the frequency drift rate of QP elements with increasing repetition period, and a decrease in the characteristic wave spectral energy density with increasing repetition period are confirmed.
New Particle Formation in the Atmosphere: From Molecular Clusters to Global Climate
Authors: Lee Shan‐Hu , Gordon Hamish , Yu Huan , Lehtipalo Katrianne , Haley Ryan , Li Yixin , Zhang Renyi
Published: June 2019

New particle formation (NPF) represents the first step in the complex processes leading to formation of cloud condensation nuclei. Newly formed nanoparticles affect human health, air quality, weather, and climate. This review provides a brief history, synthesizes recent significant progresses, and outlines the challenges and future directions for research relevant to NPF. New developments include the emergence of state‐of‐the‐art instruments that measure prenucleation clusters and newly nucleated nanoparticles down to about 1 nm; systematic laboratory studies of multicomponent nucleation systems, including collaborative experiments conducted in the Cosmics Leaving Outdoor Droplets chamber at CERN; observations of NPF in different types of forests, extremely polluted urban locations, coastal sites, polar regions, and high‐elevation sites; and improved nucleation theories and parameterizations to account for NPF in atmospheric models. The challenges include the lack of understanding of the fundamental chemical mechanisms responsible for aerosol nucleation and growth under diverse environments, the effects of SO2 and NOx on NPF, and the contribution of anthropogenic organic compounds to NPF. It is also critical to develop instruments that can detect chemical composition of particles from 3 to 20 nm and improve parameterizations to represent NPF over a wide range of atmospheric conditions of chemical precursor, temperature, and humidity.
Prediction and Inference of Flow Duration Curves Using Multioutput Neural Networks
Authors: Worland Scott. C. , Steinschneider Scott , Asquith William , Knight Rodney , Wieczorek Michael
Published: June 2019

We develop multioutput neural network models to predict flow‐duration curves (FDCs) in 9,203 ungaged locations in the Southeastern United States for six decades between 1950 and 2009. The model architecture contains multiple response variables in the output layer that correspond to individual quantiles along the FDC. During training, predictions are made for each quantile, and a combined loss function is used for back propagation and parameter updating. The loss function accounts for the covariance between the quantiles and generates physically consistent outputs (i.e., monotonically increasing quantiles with increasing nonexceedance probabilities). We use neural network dropout to generate posterior‐predictive distributions for FDCs and test model performance under cross validation. Finally, we demonstrate how local surrogate models, via the Local Interpretable Model‐agnostic Explanations method, can be used to infer the relation between basin characteristics and the predicted FDCs. Results suggest that multioutput neural network models can learn the monotonic relations between adjacent quantiles on an FDC; they result in better predictions than single‐output neural network models that predict each quantile independently, and basin characteristics are most useful for predicting smaller quantiles, whereas bias terms from neighboring quantiles are most informative for predicting higher quantiles.
Model Structure and Climate Data Uncertainty in Historical Simulations of the Terrestrial Carbon Cycle (1850–2014)
Authors: Bonan Gordon B. , Lombardozzi Danica L. , Wieder William R. , Oleson Keith W. , Lawrence David M. , Hoffman Forrest M. , Collier Nathan
Published: June 2019

The divergence among Earth system models in the terrestrial carbon cycle has prompted interest in how to reduce uncertainty. Previous studies have identified model structural uncertainty arising from process parameterizations and parameter values. The current study highlights the importance of climate forcing in generating carbon cycle uncertainty. We use simulations in which three models (Community Land Model version 4 (CLM4), CLM4.5, CLM5) with substantially different carbon cycles are forced with two climate reconstructions (CRUNCEPv7, Global Soil Wetness Project 3 version 1 (GSWP3v1)) to examine the contributions of model structure and climate to uncertainty in the carbon cycle over the period 1850–2014. Climate uncertainty for global annual net biome production exceeds one third of total uncertainty (defined as the sum of climate and model structure uncertainty) in the first half of the twentieth century, but declines after the 1950s. Global annual gross primary productivity, net primary productivity, heterotrophic respiration, and vegetation and soil carbon stocks have substantial climate uncertainty (relative to total uncertainty) throughout the simulation period. Climate forcing contributes more than one half of total uncertainty for these carbon cycle fluxes and stocks throughout boreal North America and Eurasia, some midlatitude regions, and in eastern Amazonia and western equatorial Africa during the decade 2000–2009. Comparison with observationally based data sets of the carbon cycle using model benchmarking methods provides insight into strengths and deficiencies among models and climate forcings, but we caution against overreliance on benchmarking to discriminate among models. The conceptualization of uncertainty arising from this study implies embracing multiple feasible model simulations rather than focusing on which model or simulation is best.
Machine Learning Reveals the State of Intermittent Frictional Dynamics in a Sheared Granular Fault
Authors: Ren C. X. , Dorostkar O. , Rouet‐Leduc B. , Hulbert C. , Strebel D. , Guyer R. A. , Johnson P. A. , Carmeliet J.
Published: June 2019

Seismogenic plate boundaries are posited to behave in a similar manner to a densely packed granular medium, where fault and block systems rapidly rearrange the distribution of forces within themselves, as particles do in slowly sheared granular systems. We use machine learning to show that statistical features of velocity signals from individual particles in a simulated sheared granular fault contain information regarding the instantaneous global state of intermittent frictional stick‐slip dynamics. We demonstrate that combining features built from the signals of more particles can improve the accuracy of the global model and discuss the physical basis behind the decrease in error. We show that the statistical features such as median and higher moments of the signals that represent the particle displacement in the direction of shearing are among the best predictive features. Our work provides novel insights into the applications of machine learning in studying frictional processes occurring in geophysical systems.
Lumikot: Fast Auroral Transients During the Growth Phase of Substorms
Authors: McKay D. , Paavilainen T. , Gustavsson B. , Kvammen A. , Partamies N.
Published: June 2019

The development of a magnetospheric substorm may be classified into three phases: growth, expansion, and recovery. The growth phase is important as it includes processes that lead to the expansion. In a recent growth‐phase study, a type of fast discrete auroral transient phenomena—referred to as Lumikot—were observed. The Lumikot are several kilometers across and move in the high‐energy precipitation region, parallel to the main growth‐phase arc, with both east‐west and west‐east directions of travel during the same event. Their apparent transverse movement and quasi‐stable intensity make them distinct from cooccurring optical pulsating aurorae. Comparison to other studies show that they occur in the cosmic noise absorption region and it is likely that the Lumikot are colocated with high‐energy particle populations on the boundary between the outer radiation belt and the plasmasheet.
Nonstationary Relationship Between Autumn Arctic Sea Ice and the Winter North Atlantic Oscillation
Authors: Kolstad E. W. , Screen J. A.
Published: June 2019

The North Atlantic Oscillation (NAO) has a dominating influence on wintertime weather in the North Atlantic region, and therefore, it is of great interest to predict the NAO several months ahead. While state‐of‐the‐art dynamical forecast models appear to be increasingly skillful in predicting the NAO, statistical methods with comparable or higher predictive skill are still often used. An inherent problem with statistical methods is that any empirical relationship between predictors and the NAO may be valid for some periods but subject to change over time. Here we use a set of new centennial reanalyses and large‐ensemble simulations with multiple climate models to discover clear evidence of nonstationarity in the lagged correlation between autumn Barents‐Kara sea ice and the winter NAO. This nonstationarity leads us to question the causality and/or robustness of the ice‐NAO link. We caution against indiscriminately using Barents‐Kara sea ice to predict the NAO.
Rapid Electron Acceleration in Low‐Density Regions of Saturn's Radiation Belt by Whistler Mode Chorus Waves
Authors: Woodfield E. E. , Glauert S. A. , Menietti J. D. , Averkamp T. F. , Horne R. B. , Shprits Y. Y.
Published: June 2019

Electron acceleration at Saturn due to whistler mode chorus waves has previously been assumed to be ineffective; new data closer to the planet show it can be very rapid (factor of 104 flux increase at 1 MeV in 10 days compared to factor of 2). A full survey of chorus waves at Saturn is combined with an improved plasma density model to show that where the plasma frequency falls below the gyrofrequency additional strong resonances are observed favoring electron acceleration. This results in strong chorus acceleration between approximately 2.5 RS and 5.5 RS outside which adiabatic transport may dominate. Strong pitch angle dependence results in butterfly pitch angle distributions that flatten over a few days at 100s keV, tens of days at MeV energies which may explain observations of butterfly distributions of MeV electrons near L=3. Including cross terms in the simulations increases the tendency toward butterfly distributions.
Coincident Airglow, VHF Radar, and Ionosonde Observations of Electrified Medium‐Scale Traveling Ionospheric Disturbances in the Equatorial Latitudes
Authors: Narayanan V. L. , Patra A. K. , Gurubaran S. , Pavan Chaitanya P. , Emperumal K.
Published: June 2019

The occurrence of late night spread F in the low and equatorial latitude regions during solar minimum is not properly understood. Radar observations have revealed occurrence of postmidnight echoes at low and equatorial latitudes during solar minimum periods. This work discusses the coordinated airglow, VHF radar, and ionosonde observations of nighttime electrified medium‐scale traveling ionospheric disturbances (EMSTIDs) made from the low and equatorial latitude Indian region. Two nights of observations are discussed in detail in which EMSTIDs are seen to coexist with spread F in ionograms and VHF backscatter. These observations reveal that the EMSTIDs propagate to latitudes very close to dip equator at times and they can be responsible for a reasonable portion of the postmidnight radar echoes and spread F events observed at low and equatorial latitudes during low solar activity period.
The Role of the Phase of QBO in Modulating the Influence of the SSW Effect on the Equatorial Ionosphere
Authors: Yadav Sneha , Vineeth C. , Kumar K. K. , Choudhary R. K. , Pant T. K. , Sunda S.
Published: June 2019

This study investigates the role of stratospheric quasi‐biennial oscillation (QBO) in modulating the response of equatorial/low‐latitude ionosphere over the Indian sector to the major sudden stratospheric warmings (SSWs) occurred during the period 2003 to 2013. The analysis based on the equatorial electrojet‐induced surface magnetic field, total electron content, and mesospheric wind data reveals that the equatorial ionosphere responds in distinctly different ways to the SSWs occurred during different QBO phases. The peaking time of the equatorial electrojet and occurrence time of counter electrojet displays a shift toward morning/evening sector during the westward/eastward phase of the QBO as inferred from the zonal mean zonal wind at 10‐hPa level (~30 km). The analysis reveals that the enhancement and depletions seen in total electron content over both the equatorial and low‐latitude ionosphere display a shift toward morning/evening during the westward/eastward phase of the QBO. The upper mesospheric tides (diurnal and semidiurnal) estimated using the meteor radar measured winds over the dip equator also exhibit similar shift in their phases. The occurrence of periodic counter electrojets during the SSW period is found to be coinciding with enhancement in polar stratospheric temperature and in close association with the increased amplitude of the semidiurnal tide. These observations clearly vindicate that the phase of the QBO plays a crucial role in structuring the equatorial electrodynamics and electron density distribution over the low‐latitudes during the SSW events.
A Consistent High‐Resolution Catalog of Induced Seismicity in Basel Based on Matched Filter Detection and Tailored Post‐Processing
Authors: Herrmann Marcus , Kraft Toni , Tormann Thessa , Scarabello Luca , Wiemer Stefan
Published: June 2019

Seismic monitoring of the Basel Enhanced Geothermal System has been running for more than a decade. Yet the details of the long‐term behavior of its induced seismicity remained unexplored because a seismic event catalog with consistent detection sensitivity and magnitudes did not exist. This knowledge is essential for developing guidelines and mitigation procedures on how to safely operate and terminate injection activities. Only few observational data exist that cover all phases of such projects in a consistent manner. Here we describe a method that overcomes these deficiencies based on sensitive matched filter detection and a machine learning approach to remove false detections. With an emphasis on consistency, we create a catalog that contains more than 280,000 events down toMw−1.5. The much higher temporal resolution allows us to analyze induced microearthquakes in great detail and to gain new insights. We resolved temporal variations of seismicity parameters and, in the post‐operational phase, a preferential temporal clustering of events. We find a breakdown in the Gutenberg‐Richter scaling during reservoir stimulation, which may have physical reasons or could be caused by a method‐independent detection limit during high event rates. The scaling breakdown has implications for the design of Adaptive Traffic Light Systems and may limit the potential of real‐time mitigation strategies in future Enhanced Geothermal System projects. Nevertheless, our catalog gives the opportunity to study the temporal evolution of the sequence in unprecedented detail, which will help to better understand the physical processes in a geothermal reservoir, potentially not only in the Basel case.
Probability Distribution of Turbulent Kinetic Energy Dissipation Rate in Stratified Turbulence: Microstructure Measurements in the Southern California Bight
Authors: Lozovatsky Iossif , Shearman Kipp , Pirro Annunziata , Fernando H. J. S.
Published: June 2019

A month of microstructure measurements in the Southern California Bight allowed to confirm the hypothesis that in ocean pycnocline, below the surface mixed layer, the probability distribution of turbulent kinetic energy dissipation rate ε averaged over equal time segments (2 s with 512‐Hz sampling rate, corresponding to about 1.4‐m vertical averaging) follows the Burr distribution suggested by Lozovatsky, Fernando, et al. (2017, https://doi.org/10.1002/2017JC013076). The bin‐median estimates of ε was well correlated with the medians of the Burr model. The parameters of the Burr distribution varied in time, but no relationship was found between these variations and the changes in wind patterns and phases of barotropic tide. In the range 10−9~ < ε < 10−8 W/kg, the dissipation rate could be related to internal wave activity in the region.
A 3,2-Hydroxypyridinone-based Decorporation Agent that Removes Uranium from Bones In Vivo
Authors: Wang Xiaomei , Dai Xing , Shi Cen , Wan Jianmei , Silver Mark A. , Zhang Linjuan , Chen Lanhua , Yi Xuan , Chen Bizheng , Zhang Duo , Yang Kai , Diwu Juan , Wang Jianqiang , Xu Yujie , Zhou Ruhong , Chai Zhifang , Wang Shuao
Published: June 2019

Searching for actinide decorporation agents with advantages of high decorporation efficiency, minimal biological toxicity, and high oral efficiency is crucial for nuclear safety and the sustainable development of nuclear energy. Removing actinides deposited in bones after intake is one of the most significant challenges remaining in this field because of the instantaneous formation of highly stable actinide phosphate complexes upon contact with hydroxyapatite. Here we report a hydroxypyridinone-based ligand (5LIO-1-Cm-3,2-HOPO) exhibiting stronger affinity for U(VI) compared with the reported tetradentate hydroxypyridinone ligands. This is further revealed by the first principles calculation analysis on bonding between the ligand and uranium. Both in vitro uranium removal assay and in vivo decorporation experiments with mice show that 5LIO-1-Cm-3,2-HOPO can remove uranium from kidneys and bones with high efficiencies, while the decorporation efficiency is nearly independent of the treatment time. Moreover, this ligand shows a high oral decorporation efficiency, making it attractive for practical applications.
Coevolution of vocal signal characteristics and hearing sensitivity in forest mammals
Authors: Charlton Benjamin D. , Owen Megan A. , Swaisgood Ronald R.
Published: June 2019

Although signal characteristics and sensory systems are predicted to co-evolve according to environmental constraints, this hypothesis has not been tested for acoustic signalling across a wide range of species, or any mammal sensory modality. Here we use phylogenetic comparative techniques to show that mammal vocal characteristics and hearing sensitivity have co-evolved to utilise higher frequencies in forest environments – opposite to the general prediction that lower frequencies should be favoured in acoustically cluttered habitats. We also reveal an evolutionary trade-off between high frequency hearing sensitivity and the production of calls with high frequency acoustic energy that suggests forest mammals further optimise vocal communication according to their high frequency hearing sensitivity. Our results provide clear evidence of adaptive signal and sensory system coevolution. They also emphasize how constraints imposed by the signalling environment can jointly shape vocal signal structure and auditory systems, potentially driving acoustic diversity and reproductive isolation.