bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Lithium Depletion Boundary and the Age of the Hyades Cluster∗
Authors: Martín Eduardo L. , Lodieu Nicolas , Pavlenko Yakiv , Béjar Víctor J. S. 
Published: March 2018

Abstract
Determination of the lithium depletion boundary (LDB), i.e., the observational limit below which the cores of very low-mass objects do not reach high enough temperatures for Li destruction, has been used to obtain ages for several open clusters and stellar associations younger than 200 Myr—which until now has been considered the practical upper limit on the range of applicability of this method. In this work, we show that the LDB method can be extended to significant older ages than previously thought. Intermediate resolution optical spectra of six L-type candidate members in the Hyades cluster obtained using Optical System for Imaging and Low Resolution Integrated Spectroscopy at the 10.4 m Gran Telescopio Canarias are presented. The

670.8 nm resonance doublet is clearly detected only in the two faintest and coolest of these objects, which are classified as L3.5 to L4 brown dwarf (BD) cluster members with luminosities around 10−4 solar. Lithium depletion factors are estimated for our targets with the aid of synthetic spectra and they are compared with predictions from evolutionary models. An LDB age of 650 ± 70 Myr for the Hyades provides a consistent description of our data using a set of state-of-the-art evolutionary models for BDs calculated by Baraffe et al.
An Optical and Infrared Time-domain Study of the Supergiant Fast X-Ray Transient Candidate IC 10 X-2
Authors: Kwan Stephanie , Lau Ryan M. , Jencson Jacob , Kasliwal Mansi M. , Boyer Martha L. , Ofek Eran , Masci Frank , Laher Russ 
Published: March 2018

Abstract
We present an optical and infrared (IR) study of IC 10 X-2, a high-mass X-ray binary in the galaxy IC 10. Previous optical and X-ray studies suggest that X-2 is a Supergiant Fast X-ray Transient: a large-amplitude (factor of ∼100), short-duration (hours to weeks) X-ray outburst on 2010 May 21. We analyze R- and g-band light curves of X-2 from the intermediate Palomar Transient Factory taken between 2013 July 15 and 2017 February 14 that show high-amplitude (≳1 mag), short-duration (≲8 days) flares and dips (≳0.5 mag). Near-IR spectroscopy of X-2 from Palomar/TripleSpec show He i, Paschen-γ, and Paschen-β emission lines with similar shapes and amplitudes as those of luminous blue variables (LBVs) and LBV candidates (LBVc). Mid-IR colors and magnitudes from Spitzer/Infrared Array Camera photometry of X-2 resemble those of known LBV/LBVcs. We suggest that the stellar companion in X-2 is an LBV/LBVc and discuss possible origins of the optical flares. Dips in the optical light curve are indicative of eclipses from optically thick clumps formed in the winds of the stellar counterpart. Given the constraints on the flare duration (0.02–0.8 days) and the time between flares (15.1 ± 7.8 days), we estimate the clump volume filling factor in the stellar winds, f

V
, to be

, which overlaps with values measured from massive star winds. In X-2, we interpret the origin of the optical flares as the accretion of clumps formed in the winds of an LBV/LBVc onto the compact object.
Equatorial Magnetohydrodynamic Shallow Water Waves in the Solar Tachocline
Authors: Zaqarashvili Teimuraz 
Published: March 2018

Abstract
The influence of a toroidal magnetic field on the dynamics of shallow water waves in the solar tachocline is studied. A sub-adiabatic temperature gradient in the upper overshoot layer of the tachocline causes significant reduction of surface gravity speed, which leads to trapping of the waves near the equator and to an increase of the Rossby wave period up to the timescale of solar cycles. Dispersion relations of all equatorial magnetohydrodynamic (MHD) shallow water waves are obtained in the upper tachocline conditions and solved analytically and numerically. It is found that the toroidal magnetic field splits equatorial Rossby and Rossby-gravity waves into fast and slow modes. For a reasonable value of reduced gravity, global equatorial fast magneto-Rossby waves (with the spatial scale of equatorial extent) have a periodicity of 11 years, matching the timescale of activity cycles. The solutions are confined around the equator between latitudes ±20°–40°, coinciding with sunspot activity belts. Equatorial slow magneto-Rossby waves have a periodicity of 90–100 yr, resembling the observed long-term modulation of cycle strength, i.e., the Gleissberg cycle. Equatorial magneto-Kelvin and slow magneto-Rossby-gravity waves have the periodicity of 1–2 years and may correspond to observed annual and quasi-biennial oscillations. Equatorial fast magneto-Rossby-gravity and magneto-inertia-gravity waves have periods of hundreds of days and might be responsible for observed Rieger-type periodicity. Consequently, the equatorial MHD shallow water waves in the upper overshoot tachocline may capture all timescales of observed variations in solar activity, but detailed analytical and numerical studies are necessary to make a firm conclusion toward the connection of the waves to the solar dynamo.
Delivering Chest Compressions and Ventilations With and Without Men's Lacrosse Equipment
Authors: Clark Michael D. , Davis Mikaela P. , Petschauer Meredith A. , Swartz Erik E. , Mihalik Jason P. 
Published: March 2018

Context:
Current management recommendations for equipment-laden athletes in sudden cardiac arrest regarding whether to remove protective sports equipment before delivering cardiopulmonary resuscitation are unclear.

Objective:
To determine the effect of men's lacrosse equipment on chest compression and ventilation quality on patient simulators.

Design:
Cross-sectional study.

Setting:
Controlled laboratory.

Patients or Other Participants:
Twenty-six licensed athletic trainers (18 women, 8 men; age = 25 ± 7 years; experience = 2.1 ± 1.6 years).

Intervention(s):
In a single 2-hour session, participants were block randomized to 3 equipment conditions for compressions and 6 conditions for ventilations on human patient simulators.

Main Outcome Measure(s):
Data for chest compressions (mean compression depth, compression rate, percentage of correctly released compressions, and percentage of optimal compressions) and ventilations (ventilation rate, mean ventilation volume, and percentage of ventilations delivering optimal volume) were analyzed within participants across equipment conditions.

Results:
Keeping the shoulder pads in place reduced mean compression depth (all P values &lt; .001, effect size = 0.835) and lowered the percentages of both correctly released compressions (P = .02, effect size = 0.579) and optimal-depth compressions (all P values &lt; .003, effect size = 0.900). For both the bag-valve and pocket masks, keeping the chinstrap in place reduced mean ventilation volume (all P values &lt; .001, effect size = 1.323) and lowered the percentage of optimal-volume ventilations (all P values &lt; .006, effect size = 1.038). Regardless of equipment, using a bag-valve versus a pocket mask increased the ventilation rate (all P values &lt; .003, effect size = 0.575), the percentage of optimal ventilations (all P values &lt; .002, effect size = 0.671), and the mean volume (P = .002, effect size = 0.598) across all equipment conditions.

Conclusions:
For a men's lacrosse athlete who requires cardiopulmonary resuscitation, the shoulder pads should be lifted or removed to deliver chest compressions. The facemask and chinstrap, or the entire helmet, should be removed to deliver ventilations, preferably with a bag-valve mask.
Bootstrap inversion technique for atmospheric trace gas source detection and quantification using long open-path laser measurements
Authors: Alden Caroline B. , Ghosh Subhomoy , Coburn Sean , Sweeney Colm , Karion Anna , Wright Robert , Coddington Ian , Rieker Gregory B. , Prasad Kuldeep 
Published: March 2018

Abstract. Advances in natural gas extraction technology have led to increased activity in the production and transport sectors in the United States and, as a consequence, an increased need for reliable monitoring of methane leaks to the atmosphere. We present a statistical methodology in combination with an observing system for the detection and attribution of fugitive emissions of methane from distributed potential source location landscapes such as natural gas production sites. We measure long (> 500 m), integrated open-path concentrations of atmospheric methane using a dual frequency comb spectrometer and combine measurements with an atmospheric transport model to infer leak locations and strengths using a novel statistical method, the non-zero minimum bootstrap (NZMB). The new statistical method allows us to determine whether the empirical distribution of possible source strengths for a given location excludes zero. Using this information, we identify leaking source locations (i.e., natural gas wells) through rejection of the null hypothesis that the source is not leaking. The method is tested with a series of synthetic data inversions with varying measurement density and varying levels of model–data mismatch. It is also tested with field observations of (1) a non-leaking source location and (2) a source location where a controlled emission of 3.1  ×  10−5 kg s−1 of methane gas is released over a period of several hours. This series of synthetic data tests and outdoor field observations using a controlled methane release demonstrates the viability of the approach for the detection and sizing of very small leaks of methane across large distances (4+ km2 in synthetic tests). The field tests demonstrate the ability to attribute small atmospheric enhancements of 17 ppb to the emitting source location against a background of combined atmospheric (e.g., background methane variability) and measurement uncertainty of 5 ppb (1σ), when measurements are averaged over 2 min. The results of the synthetic and field data testing show that the new observing system and statistical approach greatly decreases the incidence of false alarms (that is, wrongly identifying a well site to be leaking) compared with the same tests that do not use the NZMB approach and therefore offers increased leak detection and sizing capabilities.
Carbon–climate feedbacks accelerate ocean acidification
Authors: Matear Richard J. , Lenton Andrew 
Published: March 2018

Abstract. Carbon–climate feedbacks have the potential to significantly
impact the future climate by altering atmospheric CO2 concentrations
(Zaehle et al., 2010). By modifying the future atmospheric CO2 concentrations, the
carbon–climate feedbacks will also influence the future ocean acidification
trajectory. Here, we use the CO2 emissions scenarios from four
representative concentration pathways (RCPs) with an Earth system model to
project the future trajectories of ocean acidification with the inclusion of
carbon–climate feedbacks. We show that simulated carbon–climate feedbacks can significantly impact the
onset of undersaturated aragonite conditions in the Southern and Arctic
oceans, the suitable habitat for tropical coral and the deepwater saturation
states. Under the high-emissions scenarios (RCP8.5 and RCP6), the
carbon–climate feedbacks advance the onset of surface water under saturation
and the decline in suitable coral reef habitat by a decade or more. The
impacts of the carbon–climate feedbacks are most significant for the medium-
(RCP4.5) and low-emissions (RCP2.6) scenarios. For the RCP4.5 scenario, by
2100 the carbon–climate feedbacks nearly double the area of surface water
undersaturated with respect to aragonite and reduce by 50 % the surface
water suitable for coral reefs. For the RCP2.6 scenario, by 2100 the
carbon–climate feedbacks reduce the area suitable for coral reefs by 40 %
and increase the area of undersaturated surface water by 20 %. The
sensitivity of ocean acidification to the carbon–climate feedbacks in the low
to medium emission scenarios is important because recent CO2 emission
reduction commitments are trying to transition emissions to such a scenario.
Our study highlights the need to better characterise the carbon–climate
feedbacks and ensure we do not underestimate the projected ocean
acidification.
Modeling of quasi-static thrust load of wind turbines based on 1 s SCADA data
Authors: Noppe Nymfa , Weijtjens Wout , Devriendt Christof 
Published: March 2018

Abstract. A reliable load history is crucial for a fatigue assessment of wind turbines.
However, installing strain sensors on every wind turbine is not economically
feasible. In this paper, a technique is proposed to reconstruct the thrust
load history of a wind turbine based on high-frequency Supervisory Control
and Data Acquisition (SCADA) data. Strain measurements
recorded during a short period of time are used to train a neural network.
The selection of appropriate input parameters is performed based on Pearson
correlation and mutual information. Once the training is done, the model can
be used to predict the thrust load based on SCADA data only. The technique is
validated on two different datasets, one consisting of simulation data (using
the software FAST v8, created by Jonkman and Jonkman, 2016) obtained in a
controllable environment and one consisting of measurements taken at an
offshore wind turbine. In general, the relative error between simulated or
measured and predicted thrust load barely exceeds 15 % during normal
operation.
Use of a Scaffolded Case Study Assignment to Enhance Students’ Scientific Literacy Skills in Undergraduate Nutritional Science Education: Comparison between Traditional Lecture and Distance Education Course Formats
Authors: Monk Jennifer M , Newton Genevieve 
Published: March 2018

We investigated whether the implementation of a scaffolded case study assignment could increase student perceptions of their scientific literacy (SL) skills in a third year Nutritional Science course. The change in students’ SL perceptions were assessed by the completion of two surveys (administered at the start and end of the semester) consisting of questions probing a range of SL criteria relevant to undergraduate students. Additionally, we determined if the change in student perceived SL over the semester i) was related to their learning approach (i.e. deep versus surface approaches), as assessed by the Revised Two-Factor Study Process Questionnaire-2 (R-SPQ-2F), and ii) differed between course format, that is, in-class traditional lecture (LEC) and online distance education (DE). The LEC students (n=179) showed improvements in all ten SL outcomes assessed over the course of the semester, whereas the DE students (n=71) showed improvements in only six of the ten parameters assessed, however, the DE course started with a higher assessment of baseline SL capabilities. Additionally, the overall change in perceived SL capabilities was not associated with learning approach (i.e. surface or deep) in either class format. These data demonstrate that case-based learning assignments can promote students perceived SL capabilities in both traditional lecture and distance education course formats.
Dynamics of Zika virus outbreaks: an overview of mathematical modeling approaches
Authors: Wiratsudakul Anuwat , Suparit Parinya , Modchang Charin 
Published: March 2018

BackgroundThe Zika virus was first discovered in 1947. It was neglected until a major outbreak occurred on Yap Island, Micronesia, in 2007. Teratogenic effects resulting in microcephaly in newborn infants is the greatest public health threat. In 2016, the Zika virus epidemic was declared as a Public Health Emergency of International Concern (PHEIC). Consequently, mathematical models were constructed to explicitly elucidate related transmission dynamics.Survey MethodologyIn this review article, two steps of journal article searching were performed. First, we attempted to identify mathematical models previously applied to the study of vector-borne diseases using the search terms “dynamics,” “mathematical model,” “modeling,” and “vector-borne” together with the names of vector-borne diseases including chikungunya, dengue, malaria, West Nile, and Zika. Then the identified types of model were further investigated. Second, we narrowed down our survey to focus on only Zika virus research. The terms we searched for were “compartmental,” “spatial,” “metapopulation,” “network,” “individual-based,” “agent-based” AND “Zika.” All relevant studies were included regardless of the year of publication. We have collected research articles that were published before August 2017 based on our search criteria. In this publication survey, we explored the Google Scholar and PubMed databases.ResultsWe found five basic model architectures previously applied to vector-borne virus studies, particularly in Zika virus simulations. These include compartmental, spatial, metapopulation, network, and individual-based models. We found that Zika models carried out for early epidemics were mostly fit into compartmental structures and were less complicated compared to the more recent ones. Simple models are still commonly used for the timely assessment of epidemics. Nevertheless, due to the availability of large-scale real-world data and computational power, recently there has been growing interest in more complex modeling frameworks.DiscussionMathematical models are employed to explore and predict how an infectious disease spreads in the real world, evaluate the disease importation risk, and assess the effectiveness of intervention strategies. As the trends in modeling of infectious diseases have been shifting towards data-driven approaches, simple and complex models should be exploited differently. Simple models can be produced in a timely fashion to provide an estimation of the possible impacts. In contrast, complex models integrating real-world data require more time to develop but are far more realistic. The preparation of complicated modeling frameworks prior to the outbreaks is recommended, including the case of future Zika epidemic preparation.
Dental size variability in Central African Pygmy hunter‐gatherers and Bantu‐speaking farmers
Authors: Romero Alejandro , Ramirez‐Rozzi Fernando V. , Pérez‐Pérez Alejandro 
Published: March 2018

AbstractObjectivesOdontometric studies of African populations show high within‐group variation in tooth size. Overall, North Africans exhibit smaller dimensions than groups from eastern and southern sub‐Saharan regions, but no previous studies have analyzed the full dental metrics among extant African Pygmy hunter‐gatherers and Bantu‐speaking farmers. Furthermore, the population variability in tooth crown sizes from equatorial rainforest regions remains to be elucidated.Materials and MethodsThe mesiodistal and buccolingual diameters of the permanent teeth (I1‐M2) were measuredin vivousing high‐resolution replicas from Baka Pygmies and Mvae and Yassa Bantu‐speakers from Cameroon (western Africa). Analyses of variance were used to record sex‐related and population‐level differences in tooth sizes, and a principal component analysis of geometrically scaled measures was used to plot the odontometric variability among groups.ResultsCameroonian Baka Pygmies differ in dental size from their Bantu‐speaking neighbors. Molar teeth are larger in Pygmies than in Bantu individuals, while the anterior dentition is larger in the Bantu. Baka males exhibit significantly larger teeth than females, whereas sexual dimorphism in non‐Pygmies is only present in the anterior dentition.DiscussionOdontometric patterns and the degree of sexual dimorphism in dental size differ among Central African groups, indicating adaptation to their different forager and farmer lifestyles. In particular, the admixture of Bantu‐speakers in Baka populations is smaller than that in other western Pygmy groups. The greater dental phenetic diversity in Baka compared to that of the smaller‐toothed farmers suggests that ecogenetic and microevolutionary factors are influencing a particular divergence scenario.
Visible‐Light‐Induced Nickel‐Catalyzed Negishi Cross‐Couplings by Exogenous‐Photosensitizer‐Free Photocatalysis
Authors: Abdiaj Irini , Fontana Alberto , Gomez M. Victoria , de la Hoz Antonio , Alcázar Jesús 
Published: March 2018

AbstractThe merging of photoredox and transition‐metal catalysis has become one of the most attractive approaches for carbon–carbon bond formation. Such reactions require the use of two organo‐transition‐metal species, one of which acts as a photosensitizer and the other one as a cross‐coupling catalyst. We report herein an exogenous‐photosensitizer‐free photocatalytic process for the formation of carbon–carbon bonds by direct acceleration of the well‐known nickel‐catalyzed Negishi cross‐coupling that is based on the use of two naturally abundant metals. This finding will open new avenues in cross‐coupling chemistry that involve the direct visible‐light absorption of organometallic catalytic complexes.
A Suboptimal Dual Control Method for the Stochastic Systems with Parameters Drifting
Authors: Yang Hengzhan , Gao Song , Qian Fucai , Huang Jiaoru 
Published: March 2018

AbstractThis paper proposed a suboptimal dual control method for the stochastic systems with parameters drifting. Based on the consideration of the performance index control and the parameter estimation, the minimum variance of the system output and the estimated covariance matrix of the parameters estimation are both put into the performance index to evaluate the control quality. Furthermore, a dual control strategy is designed which is of the property of learning and control. Simulation results illustrate the effectiveness of the algorithm.
NNs‐Based Event‐Triggered Consensus Control of a Class of Uncertain Nonlinear Multi‐Agent Systems
Authors: Yang Yang , Yue Dong 
Published: March 2018

AbstractWe are concerned with the consensus problem for a class of uncertain nonlinear multi‐agent systems (MASs) connected through an undirected communication topology via event‐triggered approaches in this paper. Two distributed control strategies, the adaptive centralized event‐triggered control one and adaptive distributed event‐triggered control one, are presented utilizing neural networks (NNs) and event‐driven mechanisms, where the advantages of the proposed control laws lie that they remove the requirement for exact priori knowledge about parameters of individual agents by taking advantage of NNs approximators and they save computing and communication resources since control tasks only execute at certain instants with respect to predefined threshold functions. Also, the trigger coefficient can be regulated adaptively with dependence on state errors to ensure not only the control performance but also the efficiency of the network interactions. It is proven that all signals in the closed‐loop system are bounded and the Zeno behavior is excluded. Finally, simulation examples are presented for illustration of the theoretical claims.