bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Bayesian Approach to the Paleomagnetic Conglomerate Test
Authors: Heslop David , Roberts Andrew P. 
Published: February 2018

AbstractThe conglomerate test has served the paleomagnetic community for over 60 years as a means to detect remagnetizations. The test states that if a suite of clasts within a bed have uniformly random paleomagnetic directions, then the conglomerate cannot have experienced a pervasive event that remagnetized the clasts in the same direction. The current form of the conglomerate test is based on null hypothesis testing, which results in a binary “pass” (uniformly random directions) or “fail” (nonrandom directions) outcome. We have recast the conglomerate test in a Bayesian framework with the aim of providing more information concerning the level of support a given data set provides for a hypothesis of uniformly random paleomagnetic directions. Using this approach, we place the conglomerate test in a fully probabilistic framework that allows for inconclusive results when insufficient information is available to draw firm conclusions concerning the randomness or nonrandomness of directions. With our method, sample sets larger than those typically employed in paleomagnetism may be required to achieve strong support for a hypothesis of random directions. Given the potentially detrimental effect of unrecognized remagnetizations on paleomagnetic reconstructions, it is important to provide a means to draw statistically robust data‐driven inferences. Our Bayesian analysis provides a means to do this for the conglomerate test.
Ancient Bombardment of the Inner Solar System: Reinvestigation of the “Fingerprints” of Different Impactor Populations on the Lunar Surface
Authors: Orgel Csilla , Michael Gregory , Fassett Caleb I. , van der Bogert Carolyn H. , Riedel Christian , Kneissl Thomas , Hiesinger Harald 
Published: February 2018

AbstractThe lunar cratering record provides valuable information about the late accretion history of the inner solar system. However, our understanding of the origin, rate, and timing of the impacting projectiles is far from complete. To learn more about these projectiles, we can examine crater size‐frequency distributions (CSFDs) on the Moon. Here we reinvestigate the crater populations of 30 lunar basins (≥ 300 km) using the buffered nonsparseness correction technique, which takes crater obliteration into account, thus providing more accurate measurements for the frequencies of smaller crater sizes. Moreover, we revisit the stratigraphic relationships of basins based on N(20) crater frequencies, absolute model ages, and observation data. The buffered nonsparseness correction‐corrected CSFDs of individual basins, particularly at smaller crater diameters are shifted upward. Contrary to previous studies, the shapes of the summed CSFDs of Pre‐Nectarian (excluding South Pole‐Aitken Basin), Nectarian (including Nectaris), and Imbrian (including Imbrium) basins show no statistically significant differences and thus provide no evidence for a change of impactor population.
Overcoming Equifinality: Leveraging Long Time Series for Stream Metabolism Estimation
Authors: Appling Alison P. , Hall Robert O. , Yackulic Charles B. , Arroita Maite 
Published: February 2018

AbstractThe foundational ecosystem processes of gross primary production (GPP) and ecosystem respiration (ER) cannot be measured directly but can be modeled in aquatic ecosystems from subdaily patterns of oxygen (O2) concentrations. Because rivers and streams constantly exchange O2 with the atmosphere, models must either use empirical estimates of the gas exchange rate coefficient (K600) or solve for all three parameters (GPP, ER, and K600) simultaneously. Empirical measurements of K600 require substantial field work and can still be inaccurate. Three‐parameter models have suffered from equifinality, where good fits to O2 data are achieved by many different parameter values, some unrealistic. We developed a new three‐parameter, multiday model that ensures similar values for K600 among days with similar physical conditions (e.g., discharge). Our new model overcomes the equifinality problem by (1) flexibly relating K600 to discharge while permitting moderate daily deviations and (2) avoiding the oft‐violated assumption that residuals in O2 predictions are uncorrelated. We implemented this hierarchical state‐space model and several competitor models in an open‐source R package, streamMetabolizer. We then tested the models against both simulated and field data. Our new model reduces error by as much as 70% in daily estimates of K600, GPP, and ER. Further, accuracy benefits of multiday data sets require as few as 3 days of data. This approach facilitates more accurate metabolism estimates for more streams and days, enabling researchers to better quantify carbon fluxes, compare streams by their metabolic regimes, and investigate controls on aquatic activity.
Constraining Marsh Carbon Budgets Using Long‐Term C Burial and Contemporary Atmospheric CO2 Fluxes
Authors: Forbrich I. , Giblin A. E. , Hopkinson C. S. 
Published: February 2018

AbstractSalt marshes are sinks for atmospheric carbon dioxide that respond to environmental changes related to sea level rise and climate. Here we assess how climatic variations affect marsh‐atmosphere exchange of carbon dioxide in the short term and compare it to long‐term burial rates based on radiometric dating. The 5 years of atmospheric measurements show a strong interannual variation in atmospheric carbon exchange, varying from −104 to −233 g C m−2 a−1 with a mean of −179 ± 32 g C m−2 a−1. Variation in these annual sums was best explained by differences in rainfall early in the growing season. In the two years with below average rainfall in June, both net uptake and Normalized Difference Vegetation Index were less than in the other three years. Measurements in 2016 and 2017 suggest that the mechanism behind this variability may be rainfall decreasing soil salinity which has been shown to strongly control productivity. The net ecosystem carbon balance was determined as burial rate from four sediment cores using radiometric dating and was lower than the net uptake measured by eddy covariance (mean: 110 ± 13 g C m−2 a−1). The difference between these estimates was significant and may be because the atmospheric measurements do not capture lateral carbon fluxes due to tidal exchange. Overall, it was smaller than values reported in the literature for lateral fluxes and highlights the importance of investigating lateral C fluxes in future studies.
Automatic Detection and Classification of Buried Objects Using Ground‐Penetrating Radar for Counter‐Improvised Explosive Devices
Authors: Chantasen Nattawat , Boonpoonga Akkarat , Burintramart Santana , Athikulwongse Krit , Akkaraekthalin Prayoot 
Published: February 2018

AbstractIn this paper, a technique that can automatically detect and classify objects buried under the ground is proposed. The technique employs a ground‐penetrating radar that transmits electromagnetic waves in order to strike the objects and then receives the backscattering electromagnetic wave to perform signal processing. This signal processing is divided into four main steps as follows. First, preprocessing is used to reduce the clutter due to the effect of the media layer interface. Second, the late time of the scattering signal is estimated using a simple cross correlation. Third, a few successive poles are extracted from the scattering response at the estimated late time by using the short‐time matrix pencil method. Finally, the extracted poles are fed for object classification with different constitutions and/or shapes using a support vector machine. Simulations according to the practical situation in three southern provinces of Thailand to counter the improvised explosive devices were set up. The performance of the proposed technique was evaluated. The simulation results showed that the proposed technique can efficiently detect and classify buried objects for counter‐improvised explosive device operations in the military.
Phenotypic heterogeneity in m.3243A>G mitochondrial disease: The role of nuclear factors
Authors: Pickett Sarah J. , Grady John P. , Ng Yi Shiau , Gorman Gráinne S. , Schaefer Andrew M. , Wilson Ian J. , Cordell Heather J. , Turnbull Doug M. , Taylor Robert W. , McFarland Robert 
Published: February 2018

AbstractObjectiveThe pathogenic mitochondrial DNA m.3243A>G mutation is associated with a wide range of clinical features, making disease prognosis extremely difficult to predict. We aimed to understand the cause of this heterogeneity.MethodsWe examined the phenotypic profile of 238 adult m.3243A>G carriers (patients and asymptomatic carriers) from the UK MRC Mitochondrial Disease Patient Cohort using the Newcastle Mitochondrial Disease Adult Scale. We modeled the role of risk factors for the development of specific phenotypes using proportional odds logistic regression. As mitochondria are under the dual control of their own and the nuclear genome, we examined the role of additive nuclear genetic factors in the development of these phenotypes within 46 pedigrees from the cohort.ResultsSeizures and stroke‐like episodes affect 25% and 17% of patients, respectively; more common features include hearing impairment, gastrointestinal disturbance, psychiatric involvement, and ataxia. Age, age‐adjusted blood heteroplasmy levels, and sex are poor predictors of phenotypic severity. Hearing impairment, diabetes, and encephalopathy show the strongest associations, but pseudo‐R2 values are low (0.14–0.17). We found a high heritability estimate for psychiatric involvement (h2=0.76, P = 0.0003) and moderate estimates for cognition (h2=0.46, P = 0.0021), ataxia (h2 = 0.45, P = 0.0011), migraine (h2 = 0.41, P = 0.0138), and hearing impairment (h2 = 0.40, P = 0.0050).InterpretationOur results provide good evidence for the presence of nuclear genetic factors influencing clinical outcomes in m.3234A>G‐related disease, paving the way for future work identifying these through large‐scale genetic linkage and association studies, increasing our understanding of the pathogenicity of m.3243A>G and providing improved estimates of prognosis.
Detector design for active fault diagnosis in closed‐loop systems
Authors: Sekunda A. K. , Niemann H. H. , Poulsen N. K. 
Published: February 2018

SummaryFault diagnosis of closed‐loop systems is extremely relevant for high‐precision equipment and safety critical systems. Fault diagnosis is usually divided into 2 schemes: active and passive fault diagnosis. Recent studies have highlighted some advantages of active fault diagnosis based on dual Youla‐Jabr‐Bongiorno‐Kucera parameters. In this paper, a method for closed‐loop active fault diagnosis based on statistical detectors is given using dual Youla‐Jabr‐Bongiorno‐Kucera parameters. The goal of this paper is 2‐fold. First, the authors introduce a method for measuring a residual signal subject to white noise. Second, an optimal detector design is presented for single and multiple faults using the amplitude and phase shift of the residual signal to conduct diagnosis. Here, both the optimal case of a perfect model and the suboptimal case of a model with uncertainties are discussed. The method is successfully tested on a simulated system with parametric faults.
Organic Salt Semiconductor with High Photoconductivity and Long Carrier Lifetime
Authors: Wang Lei , Jenatsch Sandra , Ruhstaller Beat , Hinderling Christian , Gesevičius Donatas , Hany Roland , Nüesch Frank 
Published: February 2018

AbstractIntrinsic photogeneration of charge carriers in organic semiconductors is generally attributed to high energy ionization or exciton dissociation by a strong electric field. Here, high bulk photoconductivity is reported in pristine pentamethine cyanine films with photocurrent onset at the band‐edge of the organic semiconductor. Single‐layer cyanine diodes with selective hole and electron contacts show linear dependence of photocurrent with reverse voltage and light intensity. Numerical drift‐diffusion simulations reveal that the linear resistor behavior stems from low and unbalanced carrier mobilities giving rise to negative space charge. Slow bimolecular recombination kinetics of photoinduced charges obtained by time delayed charge extraction measurements show strongly reduced Langevin recombination with long carrier lifetime of the order of a millisecond. Such reduced charge carrier recombination puts forward a materials concept to be exploited in photodiodes and more generally in optoelectronic devices.
Synergistic Effect of Graphene Oxide for Impeding the Dendritic Plating of Li
Authors: Foroozan Tara , Soto Fernando A. , Yurkiv Vitaliy , Sharifi‐Asl Soroosh , Deivanayagam Ramasubramonian , Huang Zhennan , Rojaee Ramin , Mashayek Farzad , Balbuena Perla B. , Shahbazian‐Yassar Reza 
Published: February 2018

AbstractDendritic growth of lithium (Li) has severely impeded the practical application of Li‐metal batteries. Herein, a 3D conformal graphene oxide nanosheet (GOn) coating, confined into the woven structure of a glass fiber separator, is reported, which permits facile transport of Li‐ions thought its structure, meanwhile regulating the Li deposition. Electrochemical measurements illustrate a remarkably enhanced cycle life and stability of the Li‐metal anode, which is explained by various microscopy and modeling results. Utilizing scanning electron microscopy, focused ion beam, and optical imaging, the formation of an uniform Li film on the electrode surface in the case of GO‐modified samples is revealed. Ab initio molecular dynamics (AIMD) simulations suggest that Li‐ions initially get adsorbed to the lithiophilic GOn and then diffuse through defect sites. This delayed Li transfer eliminates the “tip effect” leading to a more homogeneous Li nucleation. Meanwhile, CC bonds rupture observed in the GO during AIMD simulations creates more pathways for faster Li‐ions transport. In addition, phase‐field modeling demonstrates that mechanically rigid GOn coating with proper defect size (smaller than 25 nm) can physically block the anisotropic growth of Li. This new understanding is a significant step toward the employment of 2D materials for regulating the Li deposition.
Stable and Efficient Organo‐Metal Halide Hybrid Perovskite Solar Cells via π‐Conjugated Lewis Base Polymer Induced Trap Passivation and Charge Extraction
Authors: Qin Ping‐Li , Yang Guang , Ren Zhi‐wei , Cheung Sin Hang , So Shu Kong , Chen Li , Hao Jianhua , Hou Jianhui , Li Gang 
Published: February 2018

AbstractHigh‐quality pinhole‐free perovskite film with optimal crystalline morphology is critical for achieving high‐efficiency and high‐stability perovskite solar cells (PSCs). In this study, a p‐type π‐conjugated polymer poly[(2,6‐(4,8‐bis(5‐(2‐ethylhexyl) thiophen‐2‐yl)‐benzo[1,2‐b:4,5‐b′] dithiophene))‐alt‐(5,5‐(1′,3′‐di‐2‐thienyl‐5′,7′‐bis(2‐ethylhexyl) benzo[1′,2′‐c:4′,5′‐c′] dithiophene‐4,8‐dione))] (PBDB‐T) is introduced into chlorobenzene to form a facile and effective template‐agent during the anti‐solvent process of perovskite film formation. The π‐conjugated polymer PBDB‐T is found to trigger a heterogeneous nucleation over the perovskite precursor film and passivate the trap states of the mixed perovskite film through the formation of Lewis adducts between lead and oxygen atom in PBDB‐T. The p‐type semiconducting and hydrophobic PBDB‐T polymer fills in the perovskite grain boundaries to improve charge transfer for better conductivity and prevent moisture invasion into the perovskite active layers. Consequently, the PSCs with PBDB‐T modified anti‐solvent processing leads to a high‐efficiency close to 20%, and the devices show excellent stability, retaining about 90% of the initial power conversion efficiency after 150 d storage in dry air.
Excitons and Trions in One‐Photon‐ and Two‐Photon‐Excited MoS2: A Study in Dispersions
Authors: Wibmer Leonie , Lages Sebastian , Unruh Tobias , Guldi Dirk M. 
Published: February 2018

AbstractHerein, various dispersions of MoS2 obtained by means of liquid phase exfoliation are spectroscopically, (spectro‐) electrochemically, and microscopically characterized. At the core of these studies are transient absorption assays. Importantly, small‐angle X‐ray scattering measurements are employed to corroborate the exfoliated character of the MoS2 flakes in dispersion, on the one hand, and to correlate the results with TEM, AFM, and Raman characterization in the solid state, on the other. It is, then, demonstrated that transient absorption spectroscopy responds sensitively not only to changes in the sample preparation but also to instrumental and environmental parameters. It is documented that the spectroscopic features and their underlying lifetimes are tuneable on the femto‐, pico‐, and nanosecond scales by changing, for example, the centrifugation speed, the pump fluence, or the temperature. In other words, transient absorption spectroscopy provides an in situ method to quantitatively characterize liquid dispersions of MoS2 without facing the problems of reaggregated samples due to their drying for microscopic assays. The most far reaching results stem from resonantly and nonresonantly changing the pump fluence to characterize either single‐ or multiple‐excited‐state species such as excitons, trions, and bi‐/multiexcitons and to follow their formation and deactivation pattern.
Electron Transfer in Self‐Assembled Micelles Built by Conductive Polyoxometalate‐Surfactants Showing Battery‐Like Behavior
Authors: Klaiber Alexander , Kollek Tom , Cardinal Simon , Hug Nicolas , Drechsler Markus , Polarz Sebastian 
Published: February 2018

AbstractAn ideal material for the storage of electrical energy is characterized by high specific energy and high specific power at the same time, which is a task of enormous difficulty. The so‐called redox flow battery is a highly promising approach. This new energy storage technology is based on two half‐cells containing dissolved electrochemically active species. Compared to conventional, static accumulators it is not only engineered in a unique way but also needs a tailor‐made basis of chemical materials. Therefore, many different redox‐active materials are being investigated. However, research is focused mainly on the redox properties, not taking possible synergistic effects arising from self‐assembled structures into account. Here, a novel surfactant is presented containing an electroactive polyoxometalate (POM) head connected to anthraquinone (AQ) as the relevant electron reservoir via a π‐conjugated chain. When organized into micelles, electrons put on the POM corona “slide” into their depot inside the micellar core until needed. Cyclic voltammetry proves the high reversibility and stability of this system, which therefore can be regarded as micellar energy storage.
Mechanical Terahertz Modulation Based on Single‐Layered Graphene
Authors: Cheng Long , Jin Zuanming , Ma Zongwei , Su Fuhai , Zhao Yang , Zhang Yongzhuan , Su Tongyu , Sun Yan , Xu Xueli , Meng Zhi , Bian Yuecheng , Sheng Zhigao 
Published: February 2018

AbstractThe 2D terahertz (THz) modulator, enabling efficient manipulation of such versatile band in nanoscale, is crucial for THz microdevices and systems, but its implementation is difficult and remains challenging in practice. Here, a novel 2D THz modulator based on single‐layered graphene under mechanical strain is demonstrated. Bidirectional, i.e., both positive and negative, THz modulation effect is realized by utilizing unconventionally distributed strains on graphene. Such mechanical modulation is found to be stable and reversible, and its modulation depth can exceed 26% at 1 THz under 10–2 GPa strain. Observations of both the strain and frequency dependent modulation behavior evidence the mechanical strain‐induced change of the Dirac‐like energy dispersion in graphene, which is distinctive from that of the electrical and optical approaches. Due to the reliability and wide applicability of mechanical forces, these results provide an alternative route for chip‐scale THz modulation devices based on 2D materials.
Experimental and Theoretical Investigation of the Polymer Optical Fiber Random Laser with Resonant Feedback
Authors: He Jijun , Chan Wing‐KinEdward , Cheng Xin , Tse Ming‐LeungVincent , Lu Chao , Wai Ping‐KongAlexander , Savovic Svetislav , Tam Hwa‐Yaw 
Published: February 2018

Abstract1D random fiber laser is a novel fiber‐based laser, which exhibits many unique optical properties and shows great promise for various applications including speckle‐free imaging. A multimode and coherent polymer optical fiber random laser (POFRL) is successfully fabricated by doping TiO2 nanoparticles and Rh640 perchlorate dyes in the core of a polymer optical fiber (POF). The waveguide effect provided by the POF greatly increases the multiscattering events for light propagation and results in laser cavity with much shorter length than the scattering mean free path. As an illustration of potential applications, a clear speckle‐free imaging is demonstrated using the POFRL as the illumination source. Furthermore, a four‐level Monte Carlo method‐based numerical model is proposed to describe the lasing dynamics in POFRL. The model supports the experimental work in the research field of POFRL.
Copper‐Catalyzed Oxidative Carbamoylation of N‐Arylacrylamides with Hydrazinecarboxamides Leading to 2‐(Oxindol‐3‐yl)acetamides
Authors: He Zeng‐Yang , Guo Jing‐Yu , Tian Shi‐Kai 
Published: February 2018

AbstractA tandem radical carbamoylation/cyclization reaction of N‐arylacrylamides with hydrazinecarboxamides has been developed for facile access to 2‐(oxindol‐3‐yl)acetamides, which had been utilized as precursors in the synthesis of natural bioactive pyrrolidinoindolines. In the presence of 1 mol% of copper(II) carbonate and 4 equiv. of tert‐butyl hydroperoxide, a wide range of N‐arylacrylamides underwent highly regioselective carbamoylation with hydrazinecarboxamides followed by 5‐exo‐trig cyclization to afford structurally diverse 2‐(oxindol‐3‐yl)acetamides in moderate to excellent yields.magnified image
Otolaryngologist adherence to the AAO‐HNSF Allergic Rhinitis Clinical Practice Guideline
Authors: Honeybrook Adam , Ellison Matthew , Puscas Liana , Raynor Eileen 
Published: February 2018

BackgroundIn February 2015, the American Academy of Otolaryngology–Head and Neck Surgery (AAO‐HNSF) published the Allergic Rhinitis Clinical Practice Guideline (AR‐CPG). The objective of this study was to assess otolaryngologists’ perception of the accuracy and adherence to the AR‐CPG.MethodsA survey was distributed to fellows of the American Academy of Otolaryngic Allergy and members of the American Academy of Otolaryngology–Head and Neck Surgery Foundation. A total of 601 otolaryngologists responded. The survey evaluated otolaryngologists’ demographic data, perception of the accuracy of the guideline, and adherence to the guideline action statements.ResultsThe majority of respondents were actively practicing (544 [90.5%]), for a duration of 11–30 years (308 [51.2%]), in a private practice setting (387 [64.4%]). The cohort was largely fellowship trained (348 [57.9%]) and had reviewed the guideline (428 [71.2%]). Most respondents perceived the guideline as being correct “a great deal” (295 [69.7%]) and deviated from the guideline “only a little” (302 [71.6%]). High rates of adherence to the strong guideline recommendations were observed. Respondents “always/most of the time” recommended intranasal steroids (581 [97.6%]), and oral antihistamines (439 [74%]) as primary therapy. Otolaryngologists in practice for longer were more likely to deviate from the guideline recommendations by obtaining sinonasal imaging (p = 0.007) and recommending oral leukotriene receptor antagonists as primary therapy (p = 0.0001).ConclusionOverall perception of the correctness of and adherence to the AR‐CPG was high in this cohort. Targeted education resources should be provided to otolaryngologists in practice for longer in efforts to reduce harmful or unnecessary variations in care.