bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of extreme wave events in the southern coast of Brazil
Authors: Guimarães P. V. , Farina L. , Toldo E.
Published: June 2014

Abstract. Using the model SWAN, high waves on the Southwestern Atlantic generated by extra-tropical cyclones are simulated from 2000 to 2010 and their impact on the Rio Grande do Sul coast is studied. The modeled waves are compared with buoy data and good agreement is found. The six extreme events in the period which presented significant wave heights above 5 m, on a particular point of interest, are investigated in detail. It is found that the cyclogenetic pattern between the latitudes 31.5 and 34° S, is the most favorable for developing high waves. Hovmöller diagrams for deep water show that the region between the south of Rio Grande do Sul up to latitude 31.5° S is the most energetic during a cyclone's passage, although the event of May 2008 indicate that the location of this region can vary, depending on the cyclone's displacement. On the oher hand, the Hovmöller diagrams for shallow water show that the different shoreface morphologies were responsable for focusing or dissipating the waves' energy; the regions found are in agreement with the observations of erosion and progradation regions. It can be concluded that some of the urban areas of the beaches of Hermenegildo, Cidreira, Pinhal, Tramandaí, Imbé and Torres have been more exposed during the extreme wave events at Rio Grande do Sul coast, and are more vulnerable to this natural hazard.
Looking inward to enable effective outreach: A case for customer appreciation
Authors: Goetz Melanie K.
Published: June 2014

When a new general manager overhauled a struggling utility's public relations strategy with a focus on customer relationships, the transformation was dramatic.
How GIS and GPS technology aided a utility with Hurricane Sandy planning and recovery
Authors: Kahn Christopher
Published: June 2014

Geographic information systems and global positioning systems can help utilities during both scheduled and unscheduled events, including anticipating, planning, and preparing for emergencies.
Conectando realidades: los voluntarios del cuerpo de paz en Suramérica y la Guerra Global contra la pobreza en la década de 1960
Authors: Purcell Fernando
Published: June 2014

This article examines the work of Peace Corps volunteers in South America during the 1960s. It argues that through their training in impoverished communities in the United States and their intervention in similar contexts in South America, these volunteers connected diverse visions of community action aimed at eradicating poverty. This allows an inclusion of a historical comprehension of the Peace Corps within the scenario of a Global War on Poverty. The argument derives from the analysis of letters and testimonies, press items, and official documents found in archives and libraries both in the United States and South America.
Hydrodynamic parameters of a sandy soil determined by ground‐penetrating radar inside a single ring infiltrometer
Authors: Léger Emmanuel , Saintenoy Albane , Coquet Yves
Published: June 2014

This study shows how Mualem‐van Genuchten (M‐vG) parameters can be obtained from GPR data acquired during water infiltration from a single ring infiltrometer in the case of a sandy soil. Water content profiles were generated at various time steps using HYDRUS‐1D, based on particular values of the M‐vG parameters and were converted to dielectric permittivity profiles using the Complex Refractive Index Method. The GprMax suite of programs was used to generate radargrams and to follow the wetting front progression in depth using the arrival time of the electromagnetic waves recorded by a ground‐penetrating radar (GPR). Theoretically, the 1‐D time convolution between reflectivity and GPR signal at any infiltration time step is related to the peak of the reflected signal recorded in the corresponding trace in the radargram. We used this relationship to invert the M‐vG parameters for constant and falling head infiltrations using the Shuffled Complex Evolution (SCE‐UA) algorithm. The method is presented on synthetic examples and on experiments carried out for a sandy soil. The parameters inverted are compared with values obtained in laboratory on soil samples and with disk infiltrometer measurements.
Space Weather From Explosions on the Sun: How Bad Could It Be?
Authors: Schrijver Carolus J. , Beer Jürg
Published: June 2014

The variable conditions in geospace driven by the Sun's magnetic activity, known as space weather, pose an increasing threat to society [National Research Council, 2008]. Of particular concern are the infrequent and poorly known extremes.
Texas refinery air pollution emissions are being severely underestimated
Authors: Schultz Colin
Published: June 2014

The Houston‐Galveston‐Brazoria region of southeastern Texas is home to heavy industrial investment in oil refining and petrochemical production. Pollutants emanating from the factories and refineries have repeatedly caused the region to fail national and state‐level tests for air quality and ground‐level ozone.
Effects of prolonged southward interplanetary magnetic field on low‐latitude ionospheric electron density
Authors: Bagiya Mala S. , Hazarika Rumajyoti , Laskar Fazlul I. , Sunda Surendra , Gurubaran S. , Chakrabarty D. , Bhuyan P. K. , Sridharan R. , Veenadhari B. , Pallamraju D.
Published: June 2014

The present work describes the low‐latitude ionospheric variability during an unusually prolonged (~33 h) geomagnetically disturbed condition that prevailed during 15–16 July 2012. The low‐latitude electron density in summer hemisphere, investigated using ground‐ and satellite‐based observations, responded to this by generating strong negative ionospheric storm on 16 July. The maximum electron density on 16 July over Indian low latitudes was reduced by more than 50% compared to that on a geomagnetically quiet day (14 July 2012). In contrast to the extreme reduction in total electron content (TEC) in the Northern Hemisphere, TEC from a winter hemispheric station revealed substantial (~23 total electron content unit, 1 TECU = 1016 el m−2) enhancements on the same day. This contrasting hemispherical response in TEC is suggested to be due to the combined effects of strong interhemispheric and solar‐driven day‐night winds. Further, very weak equatorial electrojet (EEJ) strength on 16 July indicated that the westward electric field perturbations in the low‐latitude ionosphere were possibly due to the disturbance dynamo effect associated with meridional circulation from polar to equatorial latitudes. Interestingly, despite reduction in the integrated EEJ strength on 15 July, the low‐latitude electron density showed substantial enhancement, highlighting the significant effect of the positive ionospheric storm on the low‐latitude ionosphere. The roles of electrodynamical/neutral‐dynamical and compositional disturbances are discussed in view of these observations to understand low‐latitude ionospheric response when geomagnetic disturbance persists for longer duration.
Mechanisms of the disappearance of sea surface temperature fronts in the subtropical North Pacific Ocean
Authors: Qiu Chunhua , Kawamura Hiroshi , Mao Huabin , Wu Jiaxue
Published: June 2014

The disappearance mechanisms of subtropical sea surface temperature (SST) fronts occurring from May to August were examined quantitatively using a simple mixed‐layer model. Weekly 2.5° data sets were matched up between satellite and in situ observations, including cloud‐free SST from Advanced Microwave Scanning Radiometer‐Earth Observing System (AMSR‐E) and Global Temperature and Salinity Profile Program (GTSPP) data. A 1.5 mixed‐layer model used in this study assumed that the temporal variation of the SST gradient was controlled by the resultant effect among the net heat flux, temperature advection (including Ekman and geostrophic), and the temperature entrainment at the bottom of the mixed layer. The net heat flux was found to provide a dominant contribution to the weakening of the SST front (decreasing SST gradient), while the temperature advection and the bottom entrainment were relatively weak. Decomposition of the net heat flux revealed that the meridional gradient of the latent heat flux is a direct factor in the weakening of the SST front, while the shortwave radiation could have indirect effects. The meridional gradient of the latent heat flux is induced by southerly winds, which in turn causes the weakening and disappearance of the SST front. Comparison of weekly and monthly averaged SST gradient modeling results with in situ observations demonstrated that the weekly SST gradient in the model agrees closely with AMSR‐E observations, but there was a large difference between the monthly SST gradient in the model and in the observations.
Flip‐teaching engineering optimization, electromagnetic product design, and nondestructive evaluation in a semester's course
Authors: Hoole Samuel Ratnajeevan H. , Sivasuthan Sivamayam , Karthik Victor U. , Hoole Paul Ratnamahilan P.
Published: June 2014

Teaching practical design to students requires first a numerical course such as on finite elements and then a course on optimization. However, because of curricular constraints, it is very difficult to get students to take two courses. This paper describes a new semester's course at Michigan State University that accomplishes this through flip teaching to tackle the challenges of time. It is the flip teaching that made it possible to cover two large courses as one. The traditional order of (a) delivering theory (b) programming ancillary tools (mesh generators, solvers), and (c) programming and solving design problems, is flipped. Pre‐constructed meshes described by design parameters and ancillary programs (solvers, mesh generators, and equipotential plotters) are given to students. They familiarize themselves with these at home so that class discussion is focused on the tough concepts inherent to finite element optimization. Further to manage time, students do the massive homework in teams of two and in the last 3 weeks, each student master's one optimization method working closely with the instructor in face‐to‐face sessions. Flip teaching was praised by all students. The final assignment with a realistic design problem (using a method specific to each student) involved a seminar where students presented their results and taught their specific method to the others. A survey proved the learning accomplished. © 2014 Wiley Periodicals, Inc. Comput Appl Eng Educ 23:374–382, 2015; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21607
Iron Silicates, Iron‐Modulated Zeolite Catalysts, and Molecular Models Thereof
Authors: Pinkert Denise , Limberg Christian
Published: June 2014

Iron centres incorporated in silicate frameworks or located in their pores have been shown to possess unique catalytic properties. As compared to aluminosilicates this area of zeolite chemistry is much younger and in the first part of this review the findings made so far are summarised. Molecular model compounds may help to understand the formation, corrosion and reactivity of such materials or to even develop new ones. Hence, the subsequent parts deal with molecular iron siloxides, the number of which is still quite limited, and their behaviour also in relation to the iron‐modified zeolites is outlined. At first, compounds based on an incompletely condensed cubic silsequioxane are discussed, before iron(III) complexes of more basic siloxide ligands with varying steric demands are described. Finally, recent developments based on branched polydentate siloxides are presented.
[2+2+1] Cycloadditions of Bis(dialkylamino)acetylenes with SiI2(Idip): Syntheses and Reactivity Studies of Unprecedented 2,3,4,5‐Tetraamino‐1 H‐siloles
Authors: Lebedev Yury N. , Das Ujjal , Chernov Oleg , Schnakenburg Gregor , Filippou Alexander C.
Published: June 2014

A novel method for the synthesis of 1H‐siloles is presented. It involves a [2+2+1] cycloaddition of the ynediamines R2NCCNR2 (R=Me, Et) with SiI2(Idip) (Idip=1,3‐bis(2,6‐diisopropylphenyl)imidazolin‐2‐ylidene) to afford the orange‐colored, highly water‐sensitive 1,1‐diiodo‐2,3,4,5‐tetraamino‐1H‐siloles SiI2{C4(NR2)4} (1‐I: R=Me; 2‐I R=Et). Treatment of 2‐I with an excess of SiBr4 afforded after I/Br exchange the 1,1‐dibromo‐1H‐silole SiBr2{C4(NEt2)4} (2‐Br). The 1H‐siloles 1‐I, 2‐I, and 2‐Br were fully characterized and their molecular structures determined by single‐crystal X‐ray diffraction. The compounds feature a slightly twisted five‐membered silacyclopenta‐2,4‐diene ring and a double/single CC bond alternation in the diene fragment. Reaction of 2‐I with the N‐heterocyclic carbene IMe4 (IMe4=1,3,4,5‐tetramethylimidazolin‐2‐ylidene) leads, after displacement of the iodide groups, to the unprecedented diiodide salt [Si(IMe4)2{C4(NEt2)4}](I)2 (3), containing a 1H‐silole dication with a four‐coordinate SiIV center. The crystal structure of 3 reveals similar bonding characteristics for the dicationic 1H‐silole to those of the neutral 1H‐siloles 1‐I–2‐Br. Two‐electron reduction of 3 with C8K affords, after elimination of one IMe4 group, the thermolabile, carbene‐stabilized 1‐silacyclopentadien‐1‐ylidene Si{C4(NEt2)4}(IMe4) (4), which was characterized by elemental analysis and 1H, 13C{1H}, and 29Si{1H} NMR spectroscopies.
Segmental hair analysis for differentiation of tilidine intake from external contamination using LC‐ESI‐MS/MS and MALDI‐MS/MS imaging
Authors: Poetzsch Michael , Baumgartner Markus R. , Steuer Andrea E. , Kraemer Thomas
Published: June 2014

Segmental hair analysis has been used for monitoring changes of consumption habit of drugs. Contamination from the environment or sweat might cause interpretative problems. For this reason, hair analysis results were compared in hair samples taken 24 h and 30 days after a single tilidine dose. The 24‐h hair samples already showed high concentrations of tilidine and nortilidine. Analysis of wash water from sample preparation confirmed external contamination by sweat as reason. The 30‐day hair samples were still positive for tilidine in all segments. Negative wash‐water analysis proved incorporation from sweat into the hair matrix. Interpretation of a forensic case was requested where two children had been administered tilidine by their nanny and tilidine/nortilidine had been detected in all hair segments, possibly indicating multiple applications. Taking into consideration the results of the present study and of MALDI‐MS imaging, a single application as cause for analytical results could no longer be excluded. Interpretation of consumption behaviour of tilidine based on segmental hair analysis has to be done with caution, even after typical wash procedures during sample preparation. External sweat contamination followed by incorporation into the hair matrix can mimic chronic intake. For assessment of external contamination, hair samples should not only be collected several weeks but also one to a few days after intake. MALDI‐MS imaging of single hair can be a complementary tool for interpretation. Limitations for interpretation of segmental hair analysis shown here might also be applicable to drugs with comparable physicochemical and pharmacokinetic properties. Copyright © 2014 John Wiley & Sons, Ltd.
Cochrane in context: Effect of timing of umbilical cord clamping in term infants on maternal and neonatal outcomes
Authors: McDonald Susan J. , Middleton Philippa , Dowswell Therese , Morris Peter S
Published: June 2014

Cochrane Review: Effect of timing of umbilical cord clamping of term infants on maternal and neonatal outcomes McDonald SJ, Middleton P, Dowswell T, Morris PS. Effect of timing of umbilical cord clamping in term infants on maternal and neonatal outcomes. Cochrane Database of Systematic Reviews 2013, Issue 7. Art. No.: CD004074. DOI: 10.1002/14651858.CD004074.pub3.

This companion piece to the review, Effect of timing of umbilical cord clamping in term infants on maternal and neonatal outcomes, contains the following pieces:

The abstract of the review

A commentary from one or more of the review authors, explaining why the review team felt the review was an important one to produce

A review of clinical practice guidelines from the American Academy of Pediatrics and the Canadian Paediatric Society

Some other recently published references on this topic
Acute toxicity tests and meta-analysis identify gaps in tropical ecotoxicology for amphibians
Authors: Ghose Sonia L. , Donnelly Maureen A. , Kerby Jacob , Whitfield Steven M.
Published: June 2014

Amphibian populations are declining worldwide, particularly in tropical regions where amphibian diversity is highest. Pollutants, including agricultural pesticides, have been identified as a potential contributor to decline, yet toxicological studies of tropical amphibians are very rare. The present study assesses toxic effects on amphibians of 10 commonly used commercial pesticides in tropical agriculture using 2 approaches. First, the authors conducted 8-d toxicity assays with formulations of each pesticide using individually reared red-eyed tree frog (Agalychnis callidryas) tadpoles. Second, they conducted a review of available data for the lethal concentration to kill 50% of test animals from the US Environmental Protection Agency's ECOTOX database to allow comparison with their findings. Lethal concentration estimates from the assays ranged over several orders of magnitude. The nematicides terbufos and ethoprophos and the fungicide chlorothalonil were very highly toxic, with evident effects within an order of magnitude of environmental concentrations. Acute toxicity assays and meta-analysis show that nematicides and fungicides are generally more toxic than herbicides yet receive far less research attention than less toxic herbicides. Given that the tropics have a high diversity of amphibians, the findings emphasize the need for research into the effects of commonly used pesticides in tropical countries and should help guide future ecotoxicological research in tropical regions. Environ Toxicol Chem 2014; 33:2114–2119. © 2014 SETAC
Four New 13,28‐Epoxyoleanane Saponins from Lysimachia lobelioides
Authors: Li Qi‐Ji , Zhu Zhu , Yang Xiao‐Sheng , Hao Xiao‐Jiang
Published: June 2014

Four new oleanane saponins, lobelioidosides A–D (1–4, resp.), all endowed with 16‐oxo and a 23‐OH group, as well as with a 13,28‐epoxy bridge as a common moiety, have been isolated from the 75% EtOH extract of the whole plant of Lysimachia lobelioides. Their structures were elucidated on the bases of MS, 1H‐ and 13C‐NMR, HMQC, HMBC, and 1H,1H‐COSY data analysis.
Preparation and Structures of 2‐Substituted 5‐Benzyl‐3‐methylimidazolidin‐4‐one‐Derived Iminium Salts, Reactive Intermediates in Organocatalytic Transformations Involving α,β‐Unsaturated Aldehydes
Authors: Grošelj Uroš , Beck Albert , Schweizer W. Bernd , Seebach Dieter
Published: June 2014

Preparations of the title compounds, 5–7 (Scheme 1 and Table 1), of their ammonium salts, 9–11 (Scheme 2 and Table 2), and of the corresponding cinnamaldehyde‐derived iminium salts 12–14 (Scheme 3 and Table 3) are reported. The X‐ray crystal structures of 15 cinnamyliminium PF6 salts have been determined (Table 4). Selected 1H‐NMR data (Table 5) of the ammonium and iminium salts are discussed, and structures in solution are compared with those in the solid state.
Induction of phenotypic plasticity in rattlesnake trophic morphology by diet manipulation
Authors: Smith Matthew T.
Published: June 2014

Gape‐limited predators are restricted in the shape and size of prey items they can ingest by their trophic morphology. Evolutionary theory predicts that gape‐limited predators, such as rattlesnakes, should possess plasticity in their trophic morphology to allow them to respond to environmental cues about their prey base. This study examined the effects of two possible influences over trophic morphology in the pit‐viper Crotalus viridis viridis. Snakes from six litters were exposed to diet manipulations performed over 480 days. By day 480, snakes from two prey‐size treatments exhibited significantly different head shapes. Snakes reared on whole rodents had broader heads, whereas snakes force‐fed homogenized prey had narrower heads. Shape differences varied among litters, suggesting that not all litters responded the same to diet manipulations. Results suggest that trophic morphology of rattlesnakes is plastic, at least in some litters, and can be induced by prey items. J. Morphol. 275:1339–1348, 2014. © 2014 Wiley Periodicals, Inc.
Thermal conductivity and properties of cyanate Ester/nanodiamond composites
Authors: Şen Ferhat , Kahraman Memet Vezir
Published: June 2014

The aim of this study was to improve thermal conductivity, thermal stability, and mechanical properties of bisphenol A dicyanate ester with the addition of nanodiamond. Cyanate ester/nanodiamond composites containing various ratios of nanodiamond were prepared. Thermal stability and thermal conductivity of the samples were evaluated by thermogravimetric analysis, differential scanning calorimetry, and laser flash method, respectively. The samples were characterized with the analysis such as gel content, water absorption capacity, and stress–strain test. Hydrophobicity of the samples was determined by contact angle measurements. Moreover, the surface morphology of the samples was investigated by a scanning electron microscopy. The obtained results prove that the cyanate ester/nanodiamond composites have good thermal and mechanical properties and can be used in many applications such as the electronic devices, materials engineering, and other emergent. Copyright © 2014 John Wiley & Sons, Ltd.
Novel conductive nanocomposites from perfluoropolyether waterborne polyurethanes and carbon nanotubes
Authors: Molina Diego , Griffini Gianmarco , Levi Marinella , Turri Stefano
Published: June 2014

The exceptional electrical conductivity of carbon nanotubes (CNTs) has been exploited for the preparation of conductive nanocomposites based on a large variety of insulating polymers. Among these, perfluoropolyether‐polyurethanes (PFPE‐PUs) represent a class of highly performing fluorinated materials with excellent water/oil repellency, chemical resistance, and substrate adhesion. The incorporation of highly conductive fillers to this class of highly performing materials allows them to be exploited in new technological and industrial fields where their unique properties need to be combined with the electrical conductivity or the electrostatic dissipation properties of carbon nanotubes. However, no studies have been presented so far on nanocomposites based on PFPE‐PUs and CNTs. In this work, polymer nanocomposites based on waterborne PFPE‐PUs and increasing amounts of carboxylated multiwall CNTs (COOH‐CNTs) were prepared and characterized for the first time. The effect of increasing concentration of COOH‐CNTs on the physical, mechanical, and surface properties of the nanocomposites was investigated by means of rheological measurements, dynamic mechanical analysis, thermal characterization, optical contact angle measurements, and scanning electron microscopy. In addition, electrical measurements showed that the highly insulating undoped PFPE‐PU system undergoes substantial modifications upon addition of COOH‐CNTs, leading to the formation of conductive nanocomposites with electrical conductivities as high as 1 S/cm. The results of this study demonstrate that the addition of COOH‐CNTs to PFPE‐PU systems represents a promising strategy to expand their possible use to technological applications where chemical stability, water/oil repellence and electrical conductivity are simultaneously required. Copyright © 2014 John Wiley & Sons, Ltd.
Post‐installed reinforcement connections at ultimate and serviceability limit states
Authors: Randl Norbert , Kunz Jakob
Published: June 2014

When reinforcing bars are post‐installed in holes drilled in cured concrete, adhesive mortars are used to create a bond between concrete and bars. Appropriate adhesives can develop higher bond strengths than standard ribbed bars cast into concrete. A detailed design concept for the anchorage length of reinforcing bars has been developed by taking into account splitting/spalling of the concrete and pullout. Pullout and splitting tests on reinforcing bars set in concrete were carried out with different adhesive mortars and with varying concrete strengths and concrete covers. When higher bond strengths than those recommended for cast‐in reinforcement are taken into account, it is important to check deformations and crack widths at the serviceability limit state (SLS) separately. For this reason, structural tests on slabs and corbels were carried out. Moreover, pullout tests on post‐installed reinforcing bars were performed in order to measure displacements at service load level.
Building bridges using the balanced lift method
Authors: Kollegger Johann , Foremniak Sara , Suza Dominik , Wimmer David , Gmainer Susanne
Published: June 2014

This article explains the process of developing a new method, called the balanced lift method, for constructing bridges based on an alternative to the bridge construction techniques used nowadays. The most common methods of building bridges are those using falsework or the cantilever method, but a rather uncommon method, the lowering of arches is seen as the origin of the balanced lift method. The idea was to create a method that would allow a bridge to be built in a very fast manner without the need for falsework, using prefabricated elements and assembling all parts together in a position – in this case vertically – that would simplify the construction process. In order to reach the final state of the bridge, the parts assembled vertically are rotated into their final horizontal position. This article contains descriptions of the development of the method, a large‐scale test and two bridges already designed using the balanced lift method.
Estimation of variances and covariances for high‐dimensional data: a selective review
Authors: Tong Tiejun , Wang Cheng , Wang Yuedong
Published: June 2014

Estimation of variances and covariances is required for many statistical methods such as t‐test, principal component analysis and linear discriminant analysis. High‐dimensional data such as gene expression microarray data and financial data pose challenges to traditional statistical and computational methods. In this paper, we review some recent developments in the estimation of variances, covariance matrix, and precision matrix, with emphasis on the applications to microarray data analysis. WIREs Comput Stat 2014, 6:255–264. doi: 10.1002/wics.1308

This article is categorized under:

Data: Types and Structure > Microarrays

Statistical and Graphical Methods of Data Analysis > Multivariate Analysis
Leaving home in Slovenia: A quantitative exploration of residential independence among young adults
Authors: Kuhar Metka , Reiter Herwig
Published: June 2014

The present paper analyzes and contextualizes the phenomenon of prolonged co‐residence of parents and young adult children in Slovenia. It analyzes the process of moving out or staying at home on the basis of a subsample of young people between 19 and 29 who are no longer at school included in the representative Slovenian field survey Youth 2010. Young people still living in the household of their parents or (legal) guardians are compared with those who have already left. The analysis considers factors associated with the status transitions from youth to adulthood; the demographic, social and economic background; and the perception of the parent–child relationship quality and parenting style by the children. Our findings point to the importance of possibilities for independent housing and the economic capacity of young people and their family. The most important factor behind moving out seems to be a stable partnership.
Derivation of a homogenized von-Kármán shell theory from 3D elasticity
Authors: Hornung Peter , Velčić Igor
Published: June 2014

We derive homogenized von Kármán shell theories starting from three dimensional nonlinear elasticity. The original three dimensional model contains two small parameters: the period of oscillation
ε
of the material properties and the thickness
h
of the shell. Depending on the asymptotic ratio of these two parameters, we obtain different asymptotic theories. In the case

h \ll \varepsilon

we identify two different asymptotic theories, depending on the ratio of
h
and

\varepsilon ^{2}

. In the case of convex shells we obtain a complete picture in the whole regime

h \ll \varepsilon

.
Isostericity and tautomerism of base pairs in nucleic acids
Authors: Westhof Eric
Published: June 2014

The natural bases of nucleic acids form a great variety of base pairs with at least two hydrogen bonds between them. They are classified in twelve main families, with the Watson–Crick family being one of them. In a given family, some of the base pairs are isosteric between them, meaning that the positions and the distances between the C1′ carbon atoms are very similar. The isostericity of Watson–Crick pairs between the complementary bases forms the basis of RNA helices and of the resulting RNA secondary structure. Several defined suites of non‐Watson–Crick base pairs assemble into RNA modules that form recurrent, rather regular, building blocks of the tertiary architecture of folded RNAs. RNA modules are intrinsic to RNA architecture are therefore disconnected from a biological function specifically attached to a RNA sequence. RNA modules occur in all kingdoms of life and in structured RNAs with diverse functions. Because of chemical and geometrical constraints, isostericity between non‐Watson–Crick pairs is restricted and this leads to higher sequence conservation in RNA modules with, consequently, greater difficulties in extracting 3D information from sequence analysis. Nucleic acid helices have to be recognised in several biological processes like replication or translational decoding. In polymerases and the ribosomal decoding site, the recognition occurs on the minor groove sides of the helical fragments. With the use of alternative conformations, protonated or tautomeric forms of the bases, some base pairs with Watson–Crick‐like geometries can form and be stabilized. Several of these pairs with Watson–Crick‐like geometries extend the concept of isostericity beyond the number of isosteric pairs formed between complementary bases. These observations set therefore limits and constraints to geometric selection in molecular recognition of complementary Watson–Crick pairs for fidelity in replication and translation processes.
ADS-B System Failure Modes and Models
Authors: Syd Ali Busyairah , Ochieng Washington , Majumdar Arnab , Schuster Wolfgang , Kian Chiew Thiam
Published: June 2014

Automatic Dependent Surveillance Broadcast (ADS-B) is envisioned to support seamless aircraft surveillance and enhanced air-to-air and air-to-ground applications. ADS-B is an integrated system, dependent on on board navigation systems to obtain aircraft state information as well as a communication data link to broadcast this information to Air Traffic Control (ATC) on the ground and other ADS-B equipped aircraft. To quantify system safety, a good understanding of the potential failure modes of the system is vital. ADS-B system failure modes include those from the communication and navigation systems and human and environmental factors, as well as ADS-B-specific components. In this paper, potential failure modes of the ADS-B system are identified using an approach developed in this paper. The end output of the approach is an ADS-B failure mode register. However, the approach is transferable to other ATC surveillance systems. The paper further provides the failure classification and modelling, and also analyses the failure modes' impact on ATC operations and finally proposes potential mitigations. It is important to note that the work carried out in this paper is based on the assumption that the ADS-B operates as the primary surveillance source for the ATC.
Predicting the risk of avian influenza A H7N9 infection in live-poultry markets across Asia
Authors: Gilbert Marius , Golding Nick , Zhou Hang , Wint G. R. William , Robinson Timothy P. , Tatem Andrew J. , Lai Shengjie , Zhou Sheng , Jiang Hui , Guo Danhuai , Huang Zhi , Messina Jane P. , Xiao Xiangming , Linard Catherine , Van Boeckel Thomas P. , Martin Vincent , Bhatt Samir , Gething Peter W. , Farrar Jeremy J. , Hay Simon I. , Yu Hongjie
Published: June 2014

Two epidemic waves of an avian influenza A (H7N9) virus have so far affected China. Most human cases have been attributable to poultry exposure at live-poultry markets, where most positive isolates were sampled. The potential geographic extent of potential re-emerging epidemics is unknown, as are the factors associated with it. Using newly assembled data sets of the locations of 8,943 live-poultry markets in China and maps of environmental correlates, we develop a statistical model that accurately predicts the risk of H7N9 market infection across Asia. Local density of live-poultry markets is the most important predictor of H7N9 infection risk in markets, underscoring their key role in the spatial epidemiology of H7N9, alongside other poultry, land cover and anthropogenic predictor variables. Identification of areas in Asia with high suitability for H7N9 infection enhances our capacity to target biosurveillance and control, helping to restrict the spread of this important disease.
Multi-wavelength photoacoustic imaging of inducible tyrosinase reporter gene expression in xenograft tumors
Authors: Paproski Robert J. , Heinmiller Andrew , Wachowicz Keith , Zemp Roger J.
Published: June 2014

Photoacoustic imaging is an emerging hybrid imaging technology capable of breaking through resolution limits of pure optical imaging technologies imposed by optical-scattering to provide fine-resolution optical contrast information in deep tissues. We demonstrate the ability of multi-wavelength photoacoustic imaging to estimate relative gene expression distributions using an inducible expression system and co-register images with hemoglobin oxygen saturation estimates and micro-ultrasound data. Tyrosinase, the rate-limiting enzyme in melanin production, is used as a reporter gene owing to its strong optical absorption and enzymatic amplification mechanism. Tetracycline-inducible melanin expression is turned on via doxycycline treatment in vivo. Serial multi-wavelength imaging reveals very low estimated melanin expression in tumors prior to doxycycline treatment or in tumors with no tyrosinase gene present, but strong signals after melanin induction in tumors tagged with the tyrosinase reporter. The combination of new inducible reporters and high-resolution photoacoustic and micro-ultrasound technology is poised to bring a new dimension to the study of gene expression in vivo.
Spacer length, label moiety interchange and probe pair orientation in a homogeneous solid-phase hybridization assay utilizing lanthanide chelate complementation
Authors: Lahdenperä Susanne , Manninen Julius , Joki Laura , Karhunen Ulla , Soukka Tero
Published: June 2014

We have studied parameters affecting DNA hybridization and lanthanide chelate complementation based signal formation in a separation-free solid-phase assay suitable for spatial multiplexing.
Chiroptical and emissive properties of a calix[4]arene-containing chiral poly(p-phenylene ethynylene) with enantioselective recognition ability
Authors: Prata José V. , Costa Alexandra I. , Pescitelli Gennaro , Pinto Hugo D.
Published: June 2014

Through a combination of intrachain and interchain effects, supramolecular chirality is achieved in solution aggregates and thin films of P1. Enantiodiscrimination is observed between (R) and (S) amine antipodes.
Paliperidone-loaded spherical solid lipid nanoparticles
Authors: Kumar Sacheen , Randhawa Jaspreet K.
Published: June 2014

Gelucire® 50/13, a macrogol glyceride, was used as a surfactant for the preparation and stabilization of paliperidone-loaded Capmul® GMS-50K matrix-based solid lipid nanoparticles (SLNs). The homogeneously distributed paliperidone did not affect the crystal structure of the lipid matrix in the SLNs.
Cascade OFF–ON–OFF fluorescent probe: dual detection of trivalent ions and phosphate ions
Authors: Wan Xuejuan , Liu Tianqi , Liu Haiyang , Gu Liqiang , Yao Youwei
Published: June 2014

A new rhodamine B-based fluorescent probe was developed for the selective cascade signaling of trivalent cations (Fe3+, Al3+, Cr3+) and phosphate anion (PO43−).
Progress in flexible dye solar cell materials, processes and devices
Authors: Brown T. M. , De Rossi F. , Di Giacomo F. , Mincuzzi G. , Zardetto V. , Reale A. , Di Carlo A.
Published: June 2014

The progress in the development of materials, processes, devices and industrialization of flexible dye solar cells is analyzed in this review.
Electron-deficient truxenone derivatives and their use in organic photovoltaics
Authors: Nielsen Christian B. , Voroshazi Eszter , Holliday Sarah , Cnops Kjell , Cheyns David , McCulloch Iain
Published: June 2014

A series of electron-deficient truxenone derivatives are investigated as fullerene alternatives in organic photovoltaic applications.
A colossal dielectric constant of an amorphous TiO2:(Nb, In) film with low loss fabrication at room temperature
Authors: Gai Zhigang , Cheng Zhenxiang , Wang Xiaolin , Zhao Lanling , Yin Na , Abah Roza , Zhao Minglei , Hong Fang , Yu Zheyin , Dou Shixue
Published: June 2014

High-performance dielectric materials continue to arouse considerable interest due to their application in the field of solid state capacitors.
Design of time modulated concentric circular and concentric hexagonal antenna array using hybrid enhanced particle swarm optimisation and differential evolution algorithm
Authors: Mangoud Mohab A. , Elragal Hassan M. , Alshara Mohamed T.
Published: June 2014

Design of circular arrays (CAs) and hexagonal arrays (HAs) with low sidelobe level (SLL) and high directivity is usually achieved by increasing the number of array elements, which leads to a high undesired mutual coupling. Therefore this study presents an efficient optimisation method and a framework to show how to design multi‐ring concentric CAs (CCA) and concentric HAs (CHAs) configurations using a hybrid enhanced particle swarm optimisation and differential evolution (hybrid EPSO/DE) optimisation technique. The presented optimum CCA and CHA have perfect invariant SLL and high directivity with low mutual coupling by keeping the inter‐element spacing not less than half a wavelength which is not possible to be achieved in CA and HA arrangements. Different configurations with two‐rings, three‐rings and four‐rings are presented. The rotation angle of outer rings and the complex excitations of array elements are first optimised. Then, this design is further optimised using a time modulation technique by controlling the switch‐on times and the phases of elements excitations of the best CCA and CHA array designs. The presented time modulated (TM) concentric CA and TM concentric HA designs attain ultra‐low SLL, reduced sideband level and maximised directivity besides reducing the dynamic range of the array excitations.
Compact high‐power broadband absorptive filters using slotted waveguide harmonic pads
Authors: Stander Tinus , Meyer Petrie , Willem van der Walt Pieter
Published: June 2014

A compact high‐power broadband absorptive filter is designed by cascading a slotted waveguide harmonic pad with a wide stop‐band reflective filter. Absorption is achieved by coupling a surface current standing wave to absorptive external auxiliary waveguides through a cascade of transversal broadwall slots in rectangular waveguide.
An Unusual Transorbital Penetrating Injury and Principles of Management
Authors: Dekker AndrewPeter , El-Sawy AbdelHamid , Rejali DariusStephen
Published: June 2014

The objective of this study was to present an unusual low velocity transorbital penetrating injury. The study design was a clinical record (case report). A 38-year-old gentleman tripped and fell face first onto the wing of an ornamental brass eagle. This penetrated the inferomedial aspect of the right orbit, breaching the lamina papyracea to extend into the ethmoid sinuses and reaching the dura of the anterior cranial fossa. The foreign body was removed in theater under a joint ophthalmology and ENT procedure. The patient was left with reduced visual acuity in the right eye but no other long-term sequelae. Transorbital penetrating injury presents unusual challenges to investigation and management requiring a multidisciplinary approach to prevent significant morbidity and mortality. If managed well the prognosis is good.
Non-equilibrium dynamics of glass-forming liquid mixtures
Authors: Sánchez-Díaz Luis Enrique , Lázaro-Lázaro Edilio , Olais-Govea José Manuel , Medina-Noyola Magdaleno
Published: June 2014

The non-equilibrium self-consistent generalized Langevin equation theory of irreversible processes in glass-forming liquids [P. Ramírez-González and M. Medina-Noyola, Phys. Rev. E 82, 061503 (2010)] is extended here to multi-component systems. The resulting theory describes the statistical properties of the instantaneous local particle concentration profiles nα(r, t) of species α in terms of the coupled time-evolution equations for the mean value \documentclass[12pt]{minimal}\begin{document}$\overline{n}_\alpha ({\bf r},t)$\end{document}n¯α(r,t) and for the covariance \documentclass[12pt]{minimal}\begin{document}$\sigma _{\alpha \beta }({\bf r},{\bf r}^{\prime };t)\equiv \overline{\delta n_\alpha ({\bf r},t)\delta n_\beta ({\bf r}^{\prime },t)}$\end{document}σαβ(r,r′;t)≡δnα(r,t)δnβ(r′,t)¯ of the fluctuations \documentclass[12pt]{minimal}\begin{document}$\delta n_\alpha ({\bf r},t) = n_\alpha ({\bf r},t)- \overline{n}_\alpha ({\bf r},t)$\end{document}δnα(r,t)=nα(r,t)−n¯α(r,t). As in the monocomponent case, these two coarse-grained equations involve a local mobility function bα(r, t) for each species, written in terms of the memory function of the two-time correlation function \documentclass[12pt]{minimal}\begin{document}$C_{\alpha \beta }({\bf r},{\bf r}^{\prime };t,t^{\prime }) \equiv \overline{\delta n_\alpha ({\bf r},t)\delta n_\beta ({\bf r}^{\prime },t^{\prime })}$\end{document}Cαβ(r,r′;t,t′)≡δnα(r,t)δnβ(r′,t′)¯. If the system is constrained to remain spatially uniform and subjected to a non-equilibrium preparation protocol described by a given temperature and composition change program T(t) and \documentclass[12pt]{minimal}\begin{document}$\overline{n}_\alpha (t)$\end{document}n¯α(t), these equations predict the irreversible structural relaxation of the partial static structure factors Sαβ(k; t) and of the (collective and self) intermediate scattering functions Fαβ(k, τ; t) and \documentclass[12pt]{minimal}\begin{document}$F^S_{\alpha \beta }(k,\tau ;t)$\end{document}FαβS(k,τ;t). We illustrate the applicability of the resulting theory with two examples involving simple model mixtures subjected to an instantaneous temperature quench: an electroneutral binary mixture of equally sized and oppositely charged hard-spheres, and a binary mixture of soft-spheres of moderate size-asymmetry.
Ageing and breakdown of thin insulating polymer films
Authors: Zakrevskii V. A. , Pakhotin V. A. , Sudar N. T.
Published: June 2014

A mechanism of ageing and breakdown of thin insulating polymer films in an electric field is described. Ageing and breakdown are attributed to the field ionization of macromolecules which is regarded as a self-accelerating process that takes place during the entire electric lifetime and results in an abrupt current increase in the breakdown channel. Calculations are compared with experimental dependences of polymer film lifetimes on electric field intensity.
Electron-phonon superconductivity in LaO0.5F0.5BiSe2
Authors: Feng Yanqing , Ding Hang-Chen , Du Yongping , Wan Xiangang , Wang Bogen , Savrasov Sergey Y. , Duan Chun-Gang
Published: June 2014

We report density functional calculations of the electronic structure, Fermi surface, phonon spectrum and electron–phonon coupling for the newly discovered superconductor LaO0.5F0.5BiSe2. It is confirmed that there is a strong Fermi surface nesting at (π,π,0), which results in unstable phonon branches. Combining the frozen phonon total energy calculations and an anharmonic oscillator model, we find that the quantum fluctuation prevents the appearance of static long–range order. The calculation shows that LaO0.5F0.5BiSe2 is highly anisotropic, and same as its cousin LaO0.5F0.5BiS2, this compound is also a conventional electron-phonon coupling induced superconductor.
Photoinduced band filling in strongly confined colloidal PbS quantum dots
Authors: Ullrich B. , Xi H. , Wang J. S.
Published: June 2014

Increase in continuous wave laser excitation (6 W/cm2 to 120 W/cm2) of colloidal PbS quantum dots in the strongly quantized regime (diameters 2.0 nm and 4.7 nm) deposited on semi-insulating GaAs and glass causes a clear blue shift (0.019 eV and 0.080 eV) of the emission spectra. Proof of the applicability of a dynamic three-dimensional band filling model is the significance of the presented results and demonstrates the effective electronic coupling in quantum dot arrays similar to superlattices. The work also reveals the influence of quantum dot sizes on photo-doping effects.
Dual-wavelength InP quantum dot lasers
Authors: Shutts S. , Smowton P. M. , Krysa A. B.
Published: June 2014

We have demonstrated a two-section dual-wavelength diode laser incorporating distributed Bragg reflectors, with a peak-wavelength separation of 62.5 nm at 300 K. Each lasing wavelength has a different temperature dependence, providing a difference-tuning of 0.11 nm/K. We discuss the mechanisms governing the light output of the two competing modes and explain how the short wavelength can be relatively insensitive to output changes at the longer wavelength. Starting from an initial condition when the output at both wavelengths are equal, a 500% increase in the long wavelength output causes the short wavelength output to fall by only 6%.
KLF2 is a rate-limiting transcription factor that can be targeted to enhance regulatory T-cell production
Authors: Pabbisetty Sudheer K. , Rabacal Whitney , Maseda Damian , Cendron Delphine , Collins Patrick L. , Hoek Kristen L. , Parekh Vrajesh V. , Aune Thomas M. , Sebzda Eric
Published: June 2014

Significance

Regulatory T cells (Tregs) are crucial for preventing autoimmunity, and thus discovering an efficient means of generating antigen-specific Tregs is a medical priority. To this end, we demonstrate that transcription factor Krüppel-like factor 2 (KLF2) is necessary for the generation of antigen-induced Tregs and their in vivo counterpart, peripheral Tregs. Moreover, pharmaceutical drugs that stabilize KLF2 protein levels during the transition from CD4
+
CD25
−
T cell to CD4
+
CD25
+
FoxP3
+
Treg augment production of these tolerizing lymphocytes. Results from this study indicate that KLF2 is a viable target for altering Treg development, which may significantly impact patients prescribed statins.