bluuebunny/crossref_metadata_2025_split huggingface dataset:
Importance of boundary layer mixing for the isotopic composition of surface vapor over the subtropical North Atlantic Ocean
Authors: Benetti Marion , Aloisi Giovanni , Reverdin Gilles , Risi Camille , Sèze Geneviève 
Published: February 2015

AbstractDuring the summer 2012, we carried out continuous measurements of the isotopic composition (δ) of water vapor over the near‐surface subtropical North Atlantic Ocean (STRASSE cruise). In this region of excess evaporation, we investigate the control of evaporation and mixing with a lower troposphere‐derived, isotopically depleted air mass on the near‐surface δ. We use a simple model to simulate the near‐surface δ as the result of a two end‐member mixing of the evaporative flux with free tropospheric air. The evaporative flux δ was estimated by the Craig and Gordon equation while the δ of the lower troposphere was taken from the LMDZ‐iso global atmospheric circulation model. This simulation considers instantaneous mixing of lower tropospheric air with the evaporated flux and neglects lateral advection. Despite these simplifications, the simulations allow to identify the controls on the near‐surface δ. The d‐excess variability is largely a consequence of varying kinetic effects during evaporation, even during a convection event when the input of tropospheric vapor was strong. Kinetic effects and mixing processes affect simultaneously the near‐surface δ and result in the vapor occupying distinct domains in the δ18O‐δD space. The relative humidity‐d‐excess relationship shows that the closure assumption overestimates the d‐excess variability at short time scales (less than a day). We interpret this as due to an effect of the residence time of the near‐surface water vapor on the d‐excess. Finally, we highlight the importance of reproducing mixing processes in models simulating isotopes over the subtropical North Atlantic Ocean and propose an extension of the closure assumption for use in initial conditions of distillation calculations.
Forecasting surface wind speeds over offshore islands near Taiwan during tropical cyclones: Comparisons of data‐driven algorithms and parametric wind representations
Authors: Wei Chih‐Chiang 
Published: February 2015

AbstractTropical cyclones often affect the western North Pacific region. Between May and October annually, enormous flood damage is frequently caused by typhoons in Taiwan. This study adopted machine learning techniques to forecast the hourly wind speeds over offshore islands near Taiwan during tropical cyclones. To develop a highly reliable surface wind speed prediction technique, the four kernel‐based support vector machines for regression (SVR) models, comprising radial basis function, linear, polynomial, and Pearson VII universal kernels were used. To ensure the accuracy of the SVR model, traditional regressions and the parametric wind representations, comprising the modified Rankine profile, Holland wind profile, and DeMaria wind profile were used to compare wind speed forecasts. The methodology was applied to two islands near Taiwan, Lanyu, and Pengjia Islets. The forecasting horizon ranged from 1 to 6 h. The results indicated that the Pearson VII SVR is the most precise of the kernel‐based SVR models, regressions, and parametric wind representations. Additionally, Typhoons Nanmadol and Saola which made landfall over Taiwan during 2011 and 2012 were simulated and examined. The results showed that the Pearson VII SVR yielded more favorable results than did the regressions and Holland wind profile. In addition, we observed that Holland wind profile seems applicable to open ocean but unsuitable for areas affected by topographic effects, such as the Central Mountain Range of Taiwan.
Spectral observations of a natural bipolar cloud‐to‐ground lightning
Authors: Xue Simin , Yuan Ping , Cen Jianyong , Li Yajun , Wang Xuejuan 
Published: February 2015

AbstractA natural bipolar cloud‐to‐ground lightning with two return strokes has been recorded with a slitless spectrograph. The subsequent positive stroke occurred retracing the preexisting channel created by the first negative stroke. They both were followed by a long continuing current going with M components. The spectra of the discharge channel for the M components were recorded first with a spectral range from 400 to 1000 nm. The spectral analysis suggests that the polarity of the discharge and the direction of the current have little effect on the structure of the spectrum, while the discharge strength, including current magnitude and duration, is the main factor determining the structure of the spectrum. The spectra of the negative and the positive return strokes are characterized by strong NII lines within the visible range, especially the two representative lines of 500.5 nm and 568.0 nm. The spectra of the M components were mainly from the contribution of OI and NI emissions in the infrared range, and typically, the four strong lines of OI 777.4 nm, NI 746.8, 821.6, and 868.0 nm were persistently observed in the spectra of the whole lightning process. In addition, the spectral characteristics in different channel sections show that background intensities for both the return strokes and all the M components have an increasing trend with increasing height along the channel. However, the intensities of NII lines for both the return strokes decrease slightly with increasing height along the channel, which should be related to the transmission characteristic of the current in the discharge channel.
Atomic‐scale simulation of space weathering in olivine and orthopyroxene
Authors: Quadery Abrar H. , Pacheco Shaun , Au Alan , Rizzacasa Natalie , Nichols Joshua , Le Timothy , Glasscock Cameron , Schelling Patrick K. 
Published: February 2015

AbstractClassical molecular dynamics was used to study the annealing of anion and cation Frenkel defects in olivine and orthopyroxene minerals. While it was found that for both minerals, reorganization of the Si–O bonds, often accompanied by large Si displacements, occurs to maintain the fourfold coordination of the SiO4 tetrahedra, important differences are observed in their annealing behavior. Specifically, cation defects are substantially more mobile in olivine than in orthopyroxene leading to rapid annihilation of cation Frenkel defects and formation of extended defects in olivine. By contrast, the diffusion rate of anion defects in orthopyroxene is much higher than that in olivine and also exhibits large anisotropy. Consequently, it was found that diffusion in orthopyroxene occurs without significant annihilation of anion Frenkel defects or trapping of anion interstitials or vacancies into clusters. The results obtained here are discussed in the context of space weathering of olivine and orthopyroxene. Specifically, two important observations are made which may explain previous experimental results. First, ion irradiation experiments that show reduced tolerance for radiation damage in orthopyroxene may be explained by the rapid, one‐dimensional anion mobility which prevents healing of the lattice. Second, laser heating experiments which show that orthopyroxene has enhanced tolerance to reduction and the evolution of nanophase Fe inclusions could be due to the observed rapid anion diffusion in orthopyroxene, which might allow the bulk to act as a reservoir for the surface.
Disappearing Arctic tundra ponds: Fine‐scale analysis of surface hydrology in drained thaw lake basins over a 65 year period (1948–2013)
Authors: Andresen Christian G. , Lougheed Vanessa L. 
Published: February 2015

AbstractLong‐term fine‐scale dynamics of surface hydrology in Arctic tundra ponds (less than 1 ha) are largely unknown; however, these small water bodies may contribute substantially to carbon fluxes, energy balance, and biodiversity in the Arctic system. Change in pond area and abundance across the upper Barrow Peninsula, Alaska, was assessed by comparing historic aerial imagery (1948) and modern submeter resolution satellite imagery (2002, 2008, and 2010). This was complemented by photogrammetric analysis of low‐altitude kite‐borne imagery in combination with field observations (2010–2013) of pond water and thaw depth transects in seven ponds of the International Biological Program historic research site. Over 2800 ponds in 22 drained thaw lake basins (DTLB) with different geological ages were analyzed. We observed a net decrease of 30.3% in area and 17.1% in number of ponds over the 62 year period. The inclusion of field observations of pond areas in 1972 from a historic research site confirms the linear downward trend in area. Pond area and number were dependent on the age of DTLB; however, changes through time were independent of DTLB age, with potential long‐term implications for the hypothesized geomorphologic landscape succession of the thaw lake cycle. These losses were coincident with increases in air temperature, active layer, and density and cover of aquatic emergent plants in ponds. Increased evaporation due to warmer and longer summers, permafrost degradation, and transpiration from encroaching aquatic emergent macrophytes are likely the factors contributing to the decline in surface area and number of ponds.
Complex terrain alters temperature and moisture limitations of forest soil respiration across a semiarid to subalpine gradient
Authors: Berryman E. M. , Barnard H. R. , Adams H. R. , Burns M. A. , Gallo E. , Brooks P. D. 
Published: February 2015

AbstractForest soil respiration is a major carbon (C) flux that is characterized by significant variability in space and time. We quantified growing season soil respiration during both a drought year and a nondrought year across a complex landscape to identify how landscape and climate interact to control soil respiration. We asked the following questions: (1) How does soil respiration vary across the catchments due to terrain‐induced variability in moisture availability and temperature? (2) Does the relative importance of moisture versus temperature limitation of respiration vary across space and time? And (3) what terrain elements are important for dictating the pattern of soil respiration and its controls? Moisture superseded temperature in explaining watershed respiration patterns, with wetter yet cooler areas higher up and on north facing slopes yielding greater soil respiration than lower and south facing areas. Wetter subalpine forests had reduced moisture limitation in favor of greater seasonal temperature limitation, and the reverse was true for low‐elevation semiarid forests. Coincident climate poorly predicted soil respiration in the montane transition zone; however, antecedent precipitation from the prior 10 days provided additional explanatory power. A seasonal trend in respiration remained after accounting for microclimate effects, suggesting that local climate alone may not adequately predict seasonal variability in soil respiration in montane forests. Soil respiration climate controls were more strongly related to topography during the drought year highlighting the importance of landscape complexity in ecosystem response to drought.
Synchronization of dissolution and precipitation fronts during infiltration‐driven replacement in porous rocks
Authors: Kondratiuk Paweł , Tredak Hanna , Ladd Anthony J. C. , Szymczak Piotr 
Published: February 2015

AbstractCoupled dissolution‐precipitation reactions, where two minerals share a common ion, occur frequently in geological replacement; the reactions are driven by an inflow of precipitating secondary ions and an outflow of dissolved primary ions. Although crystallization pressure is frequently invoked to explain volume‐preserving replacement, it cannot be operative if the chemical reactions lead to a loss of mineral volume; here the host rock that should confine the precipitating mineral is dissolving faster than the grains are growing. In this paper we propose two chemical mechanisms by which a rapid dissolution front and a slower precipitation front can be synchronized, and volume‐for‐volume replacement preserved. We analyze these mechanisms within the framework of reactive transport theory and show that morphological features observed in calcite replacement can be correlated with predictions of the models.
Evaluation of the inertial dissipation method within boundary layers using numerical simulations
Authors: Jabbari Aidin , Boegman Leon , Piomelli Ugo 
Published: February 2015

AbstractWe evaluated the accuracy of the inertial dissipation method to estimate the rate of dissipation of turbulent kinetic energy within boundary layers by performing well‐resolved numerical simulations of turbulent channel flows and comparing the dissipation calculated directly from the data, with that deduced from the frequency spectra. The convection velocity, commonly used to convert frequency spectra into wave number spectra is found to be larger than the local mean velocity by approximately a factor of 2 near the bed and about 10% in the logarithmic layer and beyond. Usage of the standard Kolmogorov constants (particularly in the vertical and spanwise directions) also leads to significant errors (50% or more) in computation of dissipation. Usage of the optimal Kolmogorov constants and the convection velocity, obtained from the simulation results could result in improved accuracy in dissipation calculation with the inertial method.
Coexisting structures from high‐ and low‐energy precipitation in fine‐scale aurora
Authors: Dahlgren H. , Lanchester B. S. , Ivchenko N. 
Published: February 2015

AbstractHigh‐resolution multimonochromatic measurements of auroral emissions have revealed the first optical evidence of coexisting small‐scale auroral features resulting from separate high‐ and low‐energy populations of precipitating electrons on the same field line. The features exhibit completely separate motion and morphology. From emission ratios and ion chemistry modeling, the average energy and energy flux of the precipitation is estimated. The high‐energy precipitation is found to form large pulsating patches of 0.1 Hz with a 3 Hz modulation, and nonpulsating coexisting discrete auroral filaments. The low‐energy precipitation is observed simultaneously on the same field line as discrete filaments with no pulsation. The simultaneous structures do not interact, and they drift with different speeds in different directions. We suggest that the high‐ and low‐energy electron populations are accelerated by separate mechanisms, at different distances from Earth. The small‐scale structures could be caused by local instabilities above the ionosphere.
A numerical study of strike‐slip bend formation with application to the Salton Sea pull‐apart basin
Authors: Ye Jiyang , Liu Mian , Wang Hui 
Published: February 2015

AbstractHow stepovers of strike‐slip faults connect to form bends is a question important for understanding the formation of push‐up ranges (restraining bends) and pull‐apart basins (releasing bends). We investigated the basic mechanics of this process in a simple three‐dimensional viscoelastoplastic finite element model. Our model predicts localized plastic strain within stepovers that may eventually lead to the formation of strike‐slip bends. Major parameters controlling strain localization include the relative fault strength, geometry of the fault system, and the plasticity model assumed. Using the Drucker‐Prager plasticity model, in which the plastic yield strength of the crust depends on both shear and normal stresses, our results show that a releasing bend is easier to develop than a restraining bend under similar conditions. These results may help explain the formation of the Salton Sea pull‐apart basin in Southern California 0.5–0.1 Ma ago, when the stepover between the Imperial Fault and the San Andreas Fault was connected by the Brawley seismic zone.
The role of tropical Atlantic SST anomalies in modulating western North Pacific tropical cyclone genesis
Authors: Huo Liwei , Guo Pinwen , Hameed Saji N. , Jin Dachao 
Published: February 2015

AbstractThe connection between north tropical Atlantic (NTA) sea surface temperature (SST) anomalies and tropical cyclone (TC) genesis over the western North Pacific (WNP) and associated physical mechanisms are investigated in this study. We demonstrate a remarkable negative correlation of WNP TC genesis frequency with the (preceding) boreal spring NTA SST anomalies. Our analysis suggests that major factors for TC genesis including distributions of large‐scale vorticity and midtropospheric humidity are rendered unfavorable by remote teleconnections while barotropic energy conversion from the large‐scale flow is suppressed. As shown in recent studies, the remote teleconnection from the Atlantic is sustained and enhanced throughout the typhoon season through local air‐sea interactions. These results suggest that boreal spring NTA SST anomaly could be a new predictor for the seasonal WNP TC activity.
Decadal changes in Gulf of Alaska upwelling source waters
Authors: Pozo Buil Mercedes , Di Lorenzo Emanuele 
Published: February 2015

AbstractDecadal changes in sea surface temperature (SST) in the Gulf of Alaska are linked to long‐term transitions in the marine ecosystem. While previous studies have identified the atmospheric variability of the Aleutian Low as an important driver of Ekman pumping and low‐frequency SST anomalies, the role of subsurface gyre‐scale dynamics remains unexplored. Using a set of reanalysis data sets from 1958 to the present, we find that subsurface temperature anomalies generated along the North Pacific Current significantly contribute through mean upwelling to decadal changes of SST in the Gulf of Alaska. This influence is comparable to the contribution associated with variations in atmospheric winds. Given the exceptional low‐frequency character of the propagation of subsurface anomalies (e.g., multidecadal) along the gyre, monitoring subsurface temperature anomalies up stream along the North Pacific Current may enhance the decadal predictability of SST in the Gulf of Alaska and its impact on local marine ecosystems.
Significant relationship between the extent of pleural plaques and pulmonary asbestos body concentration in lung cancer patients with occupational asbestos exposure
Authors: Yusa Toshikazu , Hiroshima Kenzo , Sakai Fumikazu , Kishimoto Takumi , Ohnishi Kazuo , Usami Ikuji , Morikawa Tetsuyuki , Wu Di , Itoi Kazumi , Okamoto Kenzo , Shinohara Yasushi , Kohyama Norihiko , Morinaga Kenji 
Published: February 2015

BackgroundThe aim of this study was to elucidate whether there is a relationship between the extent of pleural plaques and pulmonary asbestos body concentration (PABC).MethodsThe subjects were 207 lung cancer patients with occupational asbestos exposure. We determined the plaque extent by findings on chest images using our own criteria. PABCs were measured in resected or autopsy lung specimens.ResultsThere was a significant relationship between plaque extent and PABC. Seventy‐five percent of the patients determined to have extensive plaques based on our criteria had a PABC of ≥5,000 asbestos bodies per gram of dry lung tissue, which is one of the certification criteria of lung cancer caused by asbestos for workers' compensation in Japan.ConclusionsIn lung cancer patients, the plaque extent had a significant positive relationship with the PABC. The plaque extent would be useful as a proxy for PABC for lung cancer compensation purposes. Am. J. Ind. Med. 58:444–455, 2015. © 2015 Wiley Periodicals, Inc.
Body mass of wild bornean orangutans living in human‐dominated landscapes: Implications for understanding their ecology and conservation
Authors: Rayadin Yaya , Spehar Stephanie N. 
Published: February 2015

ABSTRACTBody mass is a key determinant of a species' ecology, including locomotion, foraging strategies, and energetics. Accurate information on the body mass of wild primates allows us to develop explanatory models for relationships among body size, ecology, and behavior and is crucial for reconstructing the ecology and behavior of fossil primates and hominins. Information on body mass can also provide indirect information on health and can be an important tool for conservation in the context of increasingly widespread habitat disturbance. This study reports body mass data recorded for wild Northeast Bornean orangutans (Pongo pygmaeus morio) during relocation efforts in forestry and oil palm plantations in East Kalimantan, Indonesia. The average mass of flanged adult males (n = 12, 74 ± 9.78 kg) and adult females (n = 7, 35.29 ± 7.32 kg) from this study were 13.6% and 9% lower, respectively, than the only other published wild Bornean orangutan body mass measurements, but the range of weights for both males and females was larger for this study. This pattern could be due to sampling error, data collection differences, or the influence of habitat disturbance, specifically a lack of access to resources, on individual health. When necessary relocations present the opportunity, we encourage researchers to prioritize the collection of body size data for the purposes of understanding ecology but also as an indirect means of monitoring population viability. As primate habitat becomes increasingly fragmented and altered by humans such data will become critical to our ability to make informed conservation decisions. Am J Phys Anthropol 157:339–346, 2015. © 2015 Wiley Periodicals, Inc.
Molekulare Erkennung in chemischen und biologischen Systemen
Authors: Persch Elke , Dumele Oliver , Diederich François 
Published: February 2015

AbstractStrukturbasiertes Ligandendesign in der medizinischen Chemie und im Pflanzenschutz beruht auf der Identifizierung und Quantifizierung von schwachen, nichtkovalenten Wechselwirkungen und dem Verständnis der Rolle von Wasser. Ein wichtiges Werkzeug zum Abrufen von vorhandenem Wissen ist die Suche in Datenbanken von kleinen Molekülen und Proteinen. Die Erstellung eines thermodynamischen Profils zusammen mit der Röntgenstrukturanalyse und theoretischen Untersuchungen ist der Schlüssel zur Aufklärung des Energieprofils der Wasserverdrängung durch den Liganden. Biologische Bindungsstellen unterscheiden sich stark in ihrer Form, konformativen Dynamik und Polarität, weshalb verschiedene Entwicklungsstrategien für Liganden benötigt werden, wie hier anhand mehrerer Fallstudien gezeigt ist. Die Wechselwirkung zwischen Dipolen ist zu einem zentralen Baustein der molekularen Erkennung geworden. Orthogonale Wechselwirkungen, Halogenbrücken und Amid⋅⋅⋅π‐Stapelung bieten neue Möglichkeiten für innovative Leitstrukturoptimierung. Die Kombination von Untersuchungen an synthetischen Modellen und biologischen Rezeptoren ist notwendig, um verlässliche Informationen über schwache, nichtkovalente Wechselwirkungen und die Rolle von Wasser zu erlangen.
Biotechnologie von Morgen: metabolisch optimierte Zellen für die bio‐basierte Produktion von Chemikalien und Treibstoffen, Materialien und Gesundheitsprodukten
Authors: Becker Judith , Wittmann Christoph 
Published: February 2015

AbstractSeit der Etablierung fermentativer Produktionsprozesse haben sich insbesondere Corynebacterium glutamicum, Escherichia coli und Saccharomyces cerevisiae als bedeutende Produktionsorganismen in der industriellen Biotechnologie durchgesetzt. Angetrieben von einem neu aufkommenden Interesse an Nachhaltigkeit und an der Verwendung nachwachsender Rohstoffe, wurden diese Mikroorganismen in den letzten Jahren zunehmend zu maßgeschneiderten Produktionsstämmen weiterentwickelt, wobei die Vielfalt und Komplexität ihrer natürlichen Syntheseleistung zugleich ein Gewinn und eine Herausforderung ist. Eine zielgerichtete Nutzbarmachung des großen metabolischen Potentials durch den synergistischen Einsatz des Systems Metabolic Engineering und der chemischen Synthese verspricht neue und innovative Konzepte für eine zukünftige Bio‐Ökonomie.