bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Water Quality on Phytoplankton Structure in Oxbow Lakes under Anthropogenic and Non‐Anthropogenic Impacts
Authors: Wilk‐Woźniak Elżbieta , Ligęza Sławomir , Shubert Elliot 
Published: June 2013

AbstractIn this study, we present the effects of environmental factors on phytoplankton in two different oxbow lakes formed from the Vistula River. One of these lakes is under extreme anthropogenic pressure, i.e. impacted by industrial and municipal effluents and characterized by high water temperature and high concentrations of ions. The other oxbow lake is located in a natural forest with some its abiotic factors lower compared to the first oxbow lake. There were significant changes among environmental parameters, which influenced significant differences between the phytoplankton populations. The dominant algae of the impacted oxbow were small centric diatoms, which are able to rapidly absorb nutrients and have a rapid turnover. The results demonstrated that human impacted lake was a habitat, where species with a broad range of ecological requirements survive. However, these habitats are also more vulnerable for the entry and colonization of invasive algal species. In the forest oxbow lake, without human impact, heterogeneity of water quality parameters resulted in different specific habitats. Oxbow lakes are important as biodiversity hotspots for rare and/or endemic species.
Quality of service analysis and resource allocation scheme for Long‐Term Evolution network
Authors: Sallabi Farag , Shuaib Khaled 
Published: June 2013

SUMMARYIn this paper, we analyze the quality of service (QoS) framework supported by the Long‐Term Evolution standard and model the behavior of a finite‐state downlink wireless fading channel based on the configurations and system parameters provided by the 3GPP Long‐Term Evolution and provide experimental results. The model can be used to provide realistic physical layer input to evaluate the performance of algorithms at the upper layers. For example, the medium access control layer will use this data to test the performance of scheduling, admission control, power control, and so on. The QoS requirements at the physical layer, the data link layer, and the cross‐layer modeling are stated. Then, we present a QoS‐based call admission control algorithm that considers admission of calls for future start‐up as well as the immediate and hand‐off calls with a certain priority admission scheme. Analytical study based on two‐dimensional Markov chain is also provided. We then use a stochastic discrete event simulator to evaluate the performance of the call admission control algorithm. The results obtained for look‐ahead admission are compelling and indicate the usefulness of making advance resource reservations. Copyright © 2013 John Wiley & Sons, Ltd.
Evidence for parallel adaptation to climate across the natural range of Arabidopsis thaliana
Authors: Stearns Frank W. , Fenster Charles B. 
Published: June 2013

AbstractHow organisms adapt to different climate habitats is a key question in evolutionary ecology and biological conservation. Species distributions are often determined by climate suitability. Consequently, the anthropogenic impact on earth's climate is of key concern to conservation efforts because of our relatively poor understanding of the ability of populations to track and evolve to climate change. Here, we investigate the ability of Arabidopsis thaliana to occupy climate space by quantifying the extent to which different climate regimes are accessible to different A. thaliana genotypes using publicly available data from a large‐scale genotyping project and from a worldwide climate database. The genetic distance calculated from 149 single‐nucleotide polymorphisms (SNPs) among 60 lineages of A. thaliana was compared to the corresponding climate distance among collection localities calculated from nine different climatic factors. A. thaliana was found to be highly labile when adapting to novel climate space, suggesting that populations may experience few constraints when adapting to changing climates. Our results also provide evidence of a parallel or convergent evolution on the molecular level supporting recent generalizations regarding the genetics of adaptation.
Lake Malawi cichlid evolution along a benthic/limnetic axis
Authors: Hulsey C. D. , Roberts R. J. , Loh Y.‐H. E. , Rupp M. F. , Streelman J. T. 
Published: June 2013

AbstractDivergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species‐rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.
An Iron(II)[1,3‐bis(2′‐pyridylimino)isoindoline] Complex as a Catalyst for Substrate Oxidation with H2O2 – Evidence for a Transient Peroxidodiiron(III) Species
Authors: Pap József S. , Cranswick Matthew A. , Balogh‐Hergovich É. , Baráth Gábor , Giorgi Michel , Rohde Gregory T. , Kaizer József , Speier Gábor , Que Lawrence 
Published: June 2013

AbstractThe complex [Fe(indH)(solvent)3](ClO4)2 (1) has been isolated from the reaction of equimolar amounts of 1,3‐bis(2′‐pyridylimino)isoindoline (indH) and Fe(ClO4)2 in acetonitrile and characterized by X‐ray crystallography and several spectroscopic techniques. It is a suitable catalyst for the oxidation of thioanisoles and benzyl alcohols with H2O2 as the oxidant. Hammett correlations and kinetic isotope effect experiments support the involvement of an electrophilic metal‐based oxidant. A metastable green species (2) is observed when 1 is reacted with H2O2 at –40 °C and has a FeIII(μ‐O)(μ‐O2)FeIII core on the basis of UV/Vis, electron paramagnetic resonance, resonance Raman, and X‐ray absorption spectroscopic data.
Redox Reactions Between Guanidine Electron Donors and Silver Dicyanamide: Synthesis of C,N Material Precursors and Coordination Polymers
Authors: Eberle Benjamin , Herrmann Hendrik , Kaifer Elisabeth , Himmel Hans‐Jörg 
Published: June 2013

AbstractReaction of the organic electron donors ttmgb [1,2,4,5‐tetrakis(tetramethylguanidinyl)benzene] and tdmegb [1,2,4,5‐tetrakis(N,N′‐dimethylethyleneguanidinyl)benzene] with two equivalents of silver dicyanamide, Ag(dca), yielded the two salts (ttmgb)(dca)2 (1a) and (tdmegb)(dca)2 (1b). Their relatively high N/C ratios motivated an analysis of their suitability as precursors to C,N materials. The compounds melt at around 200 °C and decompose at 220 (1a) and 245 °C (1b). Reactions of the organic electron donors with an excess of Ag(dca) resulted in coupled redox and coordination reactions, leading finally to coordination polymers with different dimensionalities. The oxidized guanidine units in the polymers are connected through Ag–dca–Ag bridges, leading to stacks of co‐planar C6 rings. The resulting cationic networks are neutralized by dca anions or anionic Ag(dca) chains.
Thionitrosyl‐ and Selenonitrosyliridium Complexes
Authors: Scheibel Markus G. , Klopsch Isabel , Wolf Hilke , Stollberg Peter , Stalke Dietmar , Schneider Sven 
Published: June 2013

AbstractThe activation of elemental sulfur and selenium with electrophilic iridium nitride [Ir(N){N(CHCHPtBu2)2}]+ allowed the synthesis of thionitrosyl‐ and selenonitrosyliridium complexes. The crystallographic and spectroscopic characterization of this rare series of chalcogenonitrosyl complexes [Ir(NE){N(CHCHPtBu2)2}]+ (E = none, O, S, Se) is discussed in the context of bonding models. The experimental results indicate strong Ir–N–E multiple‐bond character, in agreement with the previously proposed N–E donor–acceptor interaction as an appropriate description for the heavier chalcogens.
Concise Total Synthesis of Hydrazidomycin A, a Rare Hydrazide Metabolite of Streptomyces atratus
Authors: Meyer Florian , Ueberschaar Nico , Hertweck Christian 
Published: June 2013

AbstractHydrazidomycins A–C and elaiomycins B–C represent a family of unusual, naturally occurring enehydrazides produced by Streptomyces sp. A general synthetic approach to access these densely functionalized hydrazine derivatives is exemplified by the first total synthesis of hydrazidomycin A. The modular synthesis involves a ruthenium‐catalyzed hydroamidation of an alkyne and a hydrazide‐derived phthalimide to yield predominantly the Z‐configured enehydrazide.
Untersuchungen zu zyklisch horizontal belasteten Pfählen bei veränderlicher Lastrichtung
Authors: Rudolph Christina , Grabe Jürgen 
Published: June 2013

AbstractPfahlgründungen sind eine weitverbreitete Gründungsvariante für Offshore‐Windenergieanlagen (OWEA) und sind in diesem Anwendungsgebiet erheblichen horizontalen Lasten ausgesetzt. Diese Belastung variiert in ihrer Amplitude, Frequenz sowie Richtung und ist naturgemäß sehr schwierig zu prognostizieren. Bereits existierende Ergebnisse von Modellversuchen berücksichtigen bislang keine Änderung der Lastrichtung und sind daher nur für eindimensionale Belastungen applikabel. Untersuchungen konnten zeigen, dass eine richtungsveränderliche zyklische Belastung zu größeren Verschiebungen führen kann als eine äquivalente eindimensionale zyklische Belastung. In diesem Beitrag wird das Phänomen anhand von Modellvorstellungen erläutert und anhand der Ergebnisse von Modellversuchen quantitativ betrachtet.On the deformation behavior of laterally loaded piles with cyclic loading from a varying direction. Pile foundations are a common foundation for offshore wind energy converters. In this application area they are subjected to large lateral loading. This loading varies in amplitude, frequency and direction and is difficult to predict. Currently available analytical design methods derived from model tests do not consider a change in loading direction and are therefore applicable for one‐dimensional loading only. Investigations have shown that a change in loading direction results in higher displacements compared to an equivalent one‐dimensional cyclic loading. In this article models are presented to explain the increasing displacements and to be compared against results from physical modeling.
Quaternary channels within the Northeast German Basin and their relevance on double diffusive convective transport processes: Constraints from 3‐D thermohaline numerical simulations
Authors: Kaiser Björn Onno , Cacace Mauro , Scheck‐Wenderoth Magdalena 
Published: June 2013

Key Points

Thermohaline convection evolves within the Northeast German Basin
Thermohaline convection is characterized by a helical flow pattern
Direct auroral precipitation from the magnetotail during substorms
Authors: Ashour‐Abdalla Maha , Schriver David , Alaoui Mostafa El , Richard Robert , Walker Raymond , Goldstein Melvyn L. , Donovan Eric , Zhou Meng 
Published: June 2013

AbstractIn this study, we examine the causes of electron precipitation during a substorm on 15 February 2008 that lead to auroral brightening. We use global kinetic simulations along with spacecraft and ground‐based data. We find ~keV electrons in the region modeled in the simulation precipitate into the premidnight sector at latitudes between 71° and 75° due to two distinct physical processes: (1) higher latitude precipitation due to electrons that undergo relatively rapid non‐adiabatic pitch angle scattering into the loss cone just earthward of a reconnection region, and (2) lower latitude precipitation due to electrons that are more gradually accelerated primarily parallel to the geomagnetic field by Fermi acceleration. These latter electrons enter the loss cone much closer to Earth at ~−15 to −10 RE. The electron precipitation due to the combination of these two mechanisms coincides spatially with observed auroral brightening during the disturbed event.
The economic impact of H1N1 on Mexico's tourist and pork sectors
Authors: Rassy Dunia , Smith Richard D. 
Published: June 2013

SUMMARYBy examining tourist arrivals and pork output and trade statistics, this analysis estimates the economic impact to the Mexican tourism and pork sectors because of the H1N1 influenza pandemic. It also assesses the role of the international response in the context of this economic impact.For tourism, losing almost a million overseas visitors translated into losses of around $US2.8bn, which extended over a five‐month period, mostly because of the slow return of European travellers. For the pork industry, temporal decreases in output were observed in most of the country and related to H1N1 incidence (p = 0.048, r = 0.37). By the end of 2009, Mexico had a pork trade deficit of $US27m. The losses derived from this pandemic were clearly influenced by the risk perception created in tourist‐supplying and pork trade partners.Results suggest that the wider economic implications of health‐related emergencies can be significant and need to be considered in preparedness planning. For instance, more effective surveillance and data gathering would enable policy to target emergency funding to the sectors and regions hardest hit. These results also stress the importance of being familiar with trade networks so as to be able to anticipate the international response and respond accordingly. Copyright © 2012 John Wiley & Sons, Ltd.
Mechanical properties of methacrylate‐based model dentin adhesives: Effect of loading rate and moisture exposure
Authors: Singh Viraj , Misra Anil , Parthasarathy Ranganathan , Ye Qiang , Park Jonggu , Spencer Paulette 
Published: June 2013

AbstractThe aim of this study is to investigate the mechanical behavior of model methacrylate‐based dentin adhesives under conditions that simulate the wet oral environment. A series of monotonic and creep experiments were performed on rectangular beam samples of dentin adhesive in three‐point bending configuration under different moisture conditions. The monotonic test results show a significant effect of loading rate on the failure strength and the linear limit (yield point) of the stress‐strain response. In addition, these tests show that the failure strength is low, and the failure occurs at a smaller deformation when the test is performed under continuously changing moisture conditions. The creep test results show that under constant moisture conditions, the model dentin adhesives can have a viscoelastic response under certain low loading levels. However, when the moisture conditions vary under the same low loading levels, the dentin adhesives have an anomalous creep response accompanied by large secondary creep and high strain accumulation. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1437–1443, 2013.
Wear of novel ceramic‐on‐ceramic bearings under adverse and clinically relevant hip simulator conditions
Authors: Al‐Hajjar Mazen , Jennings Louise M. , Begand Sabine , Oberbach Thomas , Delfosse Daniel , Fisher John 
Published: June 2013

AbstractFurther development of ceramic materials for total hip replacement aim to increase fracture toughness and further reduce the incidence of bearing fracture. Edge loading due to translational mal positioning (microseparation) has replicated stripe wear, wear rates, and bimodal wear debris observed on retrievals. This method has replicated the fracture of early zirconia ceramic‐on‐ceramic bearings. This has shown the necessity of introducing microseparation conditions to the gait cycle when assessing the tribological performance of new hip replacement bearings. Two novel ceramic matrix composite materials, zirconia‐toughened alumina (ZTA) and alumina‐toughened zirconia (ATZ), were developed by Mathys Orthopädie GmbH. In this study, ATZ‐on‐ATZ and ZTA‐on‐ZTA bearing combinations were tested and compared with alumina‐on‐alumina (Al2O3‐on‐Al2O3) bearings under adverse microseparation and edge loading conditions using the Leeds II physiological anatomical hip joint simulator. The wear rate (±95% confidence limit) of ZTA‐on‐ZTA was 0.14 ± 0.10 mm3/million cycles and that of ATZ‐on‐ATZ was 0.06 ± 0.004 mm3/million cycles compared with a wear rate of 0.74 ± 1.73 mm3/million cycles for Al2O3‐on‐Al2O3 bearings. Stripe wear was evident on all bearing combinations; however, the stripe formed on the ATZ and ZTA femoral heads was thinner and shallower that that formed on the Al2O3 heads. Posttest phase composition measurements for both ATZ and ZTA materials showed no significant change in the monoclinic zirconia content. ATZ‐on‐ATZ and ZTA‐on‐ZTA showed superior wear resistance properties when compared with Al2O3‐on‐Al2O3 under adverse edge loading conditions. © 2013 The Authors Journal of Biomedical Materials Research Part B: Applied Biomaterials Published by Wiley Periodicals, Inc., 101B: 1456–1462, 2013.
Bioactive plasma electrolytic oxidation coatings—The role of the composition, microstructure, and electrochemical stability
Authors: Mohedano M. , Guzman R. , Arrabal R. , López Lacomba J.‐L. , Matykina E. 
Published: June 2013

AbstractA Plasma electrolytic oxidation (PEO) process was used to produce bioactive coatings on Ti. PEO coatings with Ca/P atomic ratio of 1.7 and 4.0 were fabricated and characterized with respect to their morphology, composition, and microstructure. AC and DC electrochemical tests were used to evaluate the effect of (i) organic additives (amino acids, proteins, vitamins, and antibiotics) in alpha‐minimum essential medium (α‐MEM) on electrochemical stability of noncoated and PEO‐coated Ti and (ii) coating composition, microstructure, and corrosion behavior on the cell response in α‐MEM. PEO‐coated Ti showed higher corrosion resistance than the noncoated Ti in MEM with and without organic additives by an order of magnitude. The corrosion resistance in α‐MEM decreased with time for nonmodified Ti and increased for PEO‐coated Ti; the latter was because of the adsorption of the proteins in the coating pores which increased the diffusion resistance. The presence of Ca and P in titanium oxide coating at the Ca/P ratio exceeding that of any stoichiometric Ca–P–O and Ca–P–O–H compounds facilitates faster osteoblast cell adhesion. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 101B: 1524–1537, 2013.
Synthesis of P(3HB‐co‐4HB) copolymer with target‐specific 4HB molar fractions using combinations of carbon substrates
Authors: Md. Iqbal Nurhezreen , Amirul A.A. 
Published: June 2013

AbstractBACKGROUNDThe incorporation of 4HB units into P(3HB) improves the material application potential as the copolymer exhibits a wide range of physical properties ranging from crystalline plastic to elastic rubber depending on the copolymer composition. Thus, the prospects of synthesizing P(3HB‐co‐4HB) copolymer with various compositions of 4HB would increase its effectiveness as biomaterial.RESULTSThe residual cell dry weight (RCDW) and PHA concentration obtained under optimized conditions, namely C/N ratio 30, K2HPO4 6.1 g L‐1, incubation period 66 h, temperature 32°C and volume‐to‐flask ratio 47/250 mL increased from 2.9 g L‐1 to 4.9 g L‐1 and 4.2 g L‐1 to 7.6 g L‐1, respectively. P(3HB‐co‐4HB) with varied Mn between 26 kDa and 270 kDa were successfully synthesized using combinations of oleic acid, 1,6‐hexanediol and/or 1,4‐butanediol. The tensile strength and Young's modulus of the copolymers varied from 2 MPa to 24 MPa and 13 MPa to 192 MPa, respectively. Tm and Tg decreased with increasing 4HB molar fractions from 170°C to 68°C and 2.5°C to −31°C, respectively.CONCLUSIONOleic acid and (NH4)2SO4 was the best carbon and nitrogen source for PHA biosynthesis. P(3HB‐co‐4HB) copolymer with targeted 4HB molar fractions ranged from 0–65 mol% were synthesized using combinations of two or more carbon substrates by Cupriavidus sp. USMAA2‐4 (DSM 19379) using mixture design. © 2013 Society of Chemical Industry
Solvothermal conversion of magadiite into zeolite omega in a glycerol–water system
Authors: Cui Miao , Wang Yu , Liu Xiaoyu , Zhu Jiang , Sun Jiangbo , Lv Nan , Meng Changgong 
Published: June 2013

AbstractBACKGROUNDZeolite omega is used as a catalyst in various fields. Expensive tetramethylammonium cations are the conventional structure‐directing agents for the synthesis of zeolite omega. In this work, glycerol was used as both solvent and structure‐directing agent instead of expensive quaternary ammonium compounds. Zeolite omega has been obtained through conversion of magadiite in this glycerol–water system. The effects of various parameters such as reaction time, temperature, alkalinity and glycerol content were discussed.RESULTSPure zeolite omega could be obtained at 120°C for 10 days with the reactants molar composition of 14 SiO2: Al2O3: 10 Na2O: 169 H2O: 200 glycerol. Water content plays an important role in the solvothermal conversion of magadiite to zeolite omega.CONCLUSIONThe zeolite omega obtained from this system is a rather pure phase free from impurities. A preferential location of the Al atoms in the six‐membered rings of the gmelinites in zeolite omega was observed. A method including extraction and calcination was introduced to remove organic species by which highly ordered pore structure of zeolite was well retained. The present work develops a novel synthesis method for zeolite omega. © 2013 Society of Chemical Industry
Effects of bark beetle‐caused tree mortality on biogeochemical and biogeophysical MODIS products
Authors: Bright Benjamin C. , Hicke Jeffrey A. , Meddens Arjan J. H. 
Published: June 2013

AbstractDisturbances affect forest‐atmosphere exchanges of carbon, water, and energy, thereby influencing weather and climate. Bark beetle outbreaks are one such disturbance type that alters biogeochemical and biogeophysical processes in forests. Few studies have documented bark beetle impacts to leaf area index (LAI), gross primary productivity (GPP), evapotranspiration (ET), land surface temperature (LST), and surface albedo with satellite observations. Our objective was to use Landsat‐derived estimates of bark beetle‐caused tree mortality and Moderate Resolution Imaging Spectroradiometer (MODIS) land surface products to estimate beetle‐caused changes in LAI, GPP, ET, LST, and surface albedo in northern Colorado. Following bark beetle‐caused tree mortality, decreases occurred in LAI (0.02–0.80 m2m−2, 1–40%), annual GPP (50–248 gC m−2 yr−1, (5–26%), and daily summer ET (0.20–0.70 mm day−1, 13–44%), whereas increases occurred in August LST (1–3.9 K) and February albedo (0.03–0.09, 19–52%). We found greater responses of these variables in areas of greater mortality severity. The extent and severity of tree mortality in northern Colorado caused substantial changes in land surface variables (9–23%) when averaged across all forested areas of our study area. Our results demonstrate that land surface variables are sensitive to bark beetle‐caused tree mortality and that bark beetle outbreaks can significantly impact biogeochemical and biogeophysical processes.