bluuebunny/crossref_metadata_2025 huggingface dataset:
Impacts of depleting forage species in the California Current
Authors: KAPLAN ISAAC C. , BROWN CHRISTOPHER J. , FULTON ELIZABETH A. , GRAY IRIS A. , FIELD JOHN C. , SMITH ANTHONY D.M.
Published: April 2013

Human demands for food and fish meal are often in direct competition with forage needs of marine mammals, birds and piscivorous harvested fish. Here, two well-developed ecosystem models for the California Current on the West Coast of the USA were used to test the impacts on other parts of the ecosystem of harvesting euphausiids, forage fish, mackerel and mesopelagic fish such as myctophids. Depleting individual forage groups to levels that led to maximum sustainable yield of those groups may have both positive and negative effects on other species in the California Current. The most common impacts were on predators of forage groups, some of which showed declines of >20% under the scenarios that involved depletion of forage groups to 40% of unfished levels. Depletion of euphausiids and forage fish, which each comprise >10% of system biomass, had the largest impact on other species. Depleting euphausiids to 40% of unfished levels altered the abundance of 13–30% of the other functional groups by >20%; while depleting forage fish to 40% altered the abundance of 20–50% of the other functional groups by >20%. There are clear trade-offs between the harvest of forage groups and the ability of the California Current to sustain other trophic levels. Though higher trophic level species, such as groundfish, are often managed on the basis of reference points that can reduce biomass to below half of unfished levels, this level of forage species removal is likely to impact the abundance of other target species, protected species and the structure of the ecosystem.
An analysis of influenza outbreaks in institutions and enclosed societies
Authors: FINNIE T. J. R. , COPLEY V. R. , HALL I. M. , LEACH S.
Published: April 2013

This paper considers the reported attack ratio arising from outbreaks of influenza in enclosed societies. These societies are isolated from the wider community and have greater opportunities for contact between members which would aid the spread of disease. While the particular kind of society (prison, care home, school, barracks, etc.) was not a significant factor in an adjusted model of attack ratio, a person's occupation within the society was. In particular, children and military personnel suffer a greater attack ratio than other occupational types (staff, prisoners, etc.). There was no temporal trend in final attack ratio nor, with the exception of 1918, do pandemic years show abnormal attack ratios. We also observed that as community size increases, the attack ratio undergoes steep nonlinear decline. This statistical analysis draws attention to how the organization of such societies, their size and the occupations of individuals within them affect the final attack ratio.
Spatial variation in female southern elephant seal mass change assessed by an accurate non-invasive photogrammetry method
Authors: Postma Martin , Bester Marthán N. , De Bruyn P.J. Nico
Published: April 2013

Physically weighing large marine mammals sequentially over time has presented researchers with a logistical challenge and has severely limited sample sizes. Using a well-established photogrammetry method we developed a simple mathematical method to calculate accurate mass measurements at specific stages in the life cycle of a top marine predator. Female southern elephant seals (n= 23) at Marion Island were sampled sequentially using photogrammetry and three-dimensional models (based on each photogrammetry project) were built for estimation of body mass. Simple equations were applied to obtain mass at critical instances in their life cycle. Marion Island elephant seal mass data was compared to data obtained from physically weighed elephant seals from King George, South Georgia and Macquarie islands. Females from Marion Island are smaller, but their percentage lactation mass loss is similar to females from these other populations. The similarity of percentage mass loss during lactation between different female populations illustrates the accuracy and practicality of the photogrammetric method over a temporal scale. Photogrammetric mass estimation can be used alongside datasets of physically weighed animals and can greatly benefit ecology and life history studies.
Succession to the Crown Bill: Possible Untoward Effects?
Authors: Morris Bob
Published: April 2013

This Comment asks whether, in the light of early parliamentary proceedings, the Succession to the Crown Bill risks any untoward, unintended practical consequences, and considers what, if any, may be among the longer-term, less direct implications for Church establishment in England.
Religious Symbolism and Conscientious Objection in the Workplace: An Evaluation of Strasbourg's Judgment in Eweida and others v United Kingdom
Authors: Hill Mark
Published: April 2013

The judgment of the European Court of Human Rights in Eweida and others v United Kingdom1 related to two pairs of cases.2 The first pair concerned a British Airways check-in clerk and a nurse, each of whom complained that dress codes at their respective places of work prevented them from openly wearing a small cross on a chain around their neck. In the second pair, a registrar of marriages and a relationship counsellor refused to offer their respective services to same-sex couples on the basis that homosexual acts were incompatible with their religious beliefs. Having failed to obtain relief in the domestic courts, all four applicants took their claims to Strasbourg, which heard oral argument last September. Judgment was pronounced on 15 January 2013. This Comment considers the broad thrust of the judgment, particularly the threefold manner by which the Court has clarified and embedded the right to freedom of religion, the practical outcome in the individual cases, and the likely effect of the judgment upon future litigation in the domestic courts of the United Kingdom.
Krivine's classical realisability from a categorical perspective
Authors: STREICHER THOMAS
Published: April 2013

In a sequence of papers (Krivine 2001; Krivine 2003; Krivine 2009), J.-L. Krivine introduced his notion of classical realisability for classical second-order logic and Zermelo–Fraenkel set theory. Moreover, in more recent work (Krivine 2008), he has considered forcing constructions on top of it with the ultimate aim of providing a realisability interpretation for the axiom of choice.

The aim of the current paper is to show how Krivine's classical realisability can be understood as an instance of the categorical approach to realisability as started by Martin Hyland in Hyland (1982) and described in detail in van Oosten (2008). Moreover, we will give an intuitive explanation of the iteration of realisability as described in Krivine (2008).
In Situ Electron Backscatter Diffraction Investigation of Recrystallization in a Copper Wire
Authors: Brisset François , Helbert Anne-Laure , Baudin Thierry
Published: April 2013

The microstructural evolution of a cold drawn copper wire (reduction area of 38%) during primary recrystallization and grain growth was observed in situ by electron backscatter diffraction. Two thermal treatments were performed, and successive scans were acquired on samples undergoing heating from ambient temperature to a steady state of 200°C or 215°C. During a third in situ annealing, the temperature was continuously increased up to 600°C. Nuclei were observed to grow at the expense of the deformed microstructure. This growth was enhanced by the high stored energy difference between the nuclei and their neighbors (driving energy in recrystallization) and by the presence of high-angle grain boundaries of high mobility. In the early stages of growth, the nuclei twin and the newly created orientations continue to grow to the detriment of the strained copper. At high temperatures, the disappearance of some twins was evidenced by the migration of the incoherent twin boundaries. Thermal grooving of grain boundaries is observed at these high temperatures and affects the high mobile boundaries but tends to preserve the twin boundaries of lower energy. Thus, grooving may contribute to the twin vanishing.
It's a Bird, It's a Plane: Some Remarks on theAirbusAppellate Body Report (EC and Certain Member States – Large Civil Aircraft, WT/DS316/AB/R)
Authors: HAHN MICHAEL , MEHTA KIRTIKUMAR
Published: April 2013

The emergence of Airbus transformed the market structure of the LCA industry into a duopoly of similar-sized full-range manufacturers. The financing of Airbus's upfront investment expenditures came in a significant proportion from public funds, which violated, in the US's opinion the SCM Agreement. While the Appellate Body follows this view of things to a large extent, it does so in a measured way: the category ofper seillegal export subsidies is interpreted with a view to the manipulation of normal market conditions; the distortion on competitive conditions matters, not the increase of exports as such. Other aspects of subsidies law clarified are the relationship between effect and subsidy. They are closely related but not identical; rightly, the report operates from the premise that the SCM Agreement's regime focuses on the effect, and not on the subsidy as such, which is a manifestation of a political choice by a sovereign Member state. The Appellate Body affirms that a subsidy has a ‘life’, a shorthand for a beginning and an end: it follows that the effect of a subsidy is not bound to be permanent but is bound to terminate. It is to be regretted that the Appellate Body avoided clarifying to what extent partial privatization, hence sale of assets at market prices to private investors, ‘extinguish’ subsidies.
One (Firm) Is Not Enough: A Legal–Economic Analysis ofEC–Fasteners
Authors: BOWN CHAD P. , MAVROIDIS PETROS C.
Published: April 2013

The WTO's Appellate Body (AB) dealt with a number of issues for the first time in this Report. Importantly, it discussed the consistency of the European Union (EU) regulation with the multilateral rules on the conditions for deviating from the obligation to calculate individual dumping margins. Although China formally won the argument, the AB may have opened the door to treat China as a nonmarket economy (NME) even beyond 2016 when China's NME status was thought to expire under the terms of China's 2001 WTO Accession Protocol. The AB further dealt with numerous other issues ranging from statistical sampling to the treatment of confidential information. In handling its investigation, the EU authorities made a number of questionable decisions regarding the collection of information, and this aspect of the process was central to China's legal challenges.
US–Tyres: Upholding a WTO Accession Contract – Imposing Pain for Little Gain
Authors: CHARNOVITZ STEVE , HOEKMAN BERNARD
Published: April 2013

In 2009, the United States imposed additional tariffs for a three-year period on imports of automotive tires from China under a special-safeguard provision included in China's Protocol of Accession to the WTO. China challenged the measure in the WTO. The case marked the first WTO dispute in which a challenged safeguard was upheld by the Appellate Body; the first in which an accession protocol was used successfully as a defense; and the first that China lost as a complaining party. It also was noteworthy in that the safeguard was sought by a labor union, not the domestic industry. This paper reviews the WTO Appellate Body's findings and discusses a number of the legal and policy implications regarding China's Accession Protocol, the Safeguards Agreement, and WTO accession law, as well as economic aspects of the case.
United States – Use of Zeroing in Anti-Dumping Measures Involving Products from Korea:It's déjà vu all over again
Authors: PRUSA THOMAS J. , RUBINI LUCA
Published: April 2013

This paper analyzes the dispute between Korea and the United States regarding the method of calculating anti-dumping duties. The case mirrors other recent WTO disputes involving zeroing. Even though it ceased zeroing in original investigations in December 2006, the United States implemented the policy change only prospectively. As a result, the margins applied to the products in this dispute remained unchanged because they had been calculated prior to the policy change. The United States did not contest Korea's claims. The Panel confirmed that zeroing was used and, following the long line of Panel and Appellate Body rulings, found the practice inconsistent with the Anti-Dumping Agreement. After the Panel Report was adopted, the United States recalculated the margins without zeroing. It, however, refused to refund unliquidated cash deposits that were based on zeroing, highlighting the United States's continued lukewarm compliance with WTO rulings on zeroing. This dispute offers an opportunity to ponder on weaknesses of the WTO Dispute Settlement and the ability of one Member to take advantage of it. Since the facts and their legal assessment were undisputed, why was litigation necessary? Can compliance with WTO law be improved with broader findings and more incisive remedies?
How Easy Is an Easy Case for a Complainant? Comment on US–Zeroing (Korea) DS402
Authors: HUERTA-GOLDMAN JORGE A.
Published: April 2013

This article is about how easy a WTO case is when the defendant concedes the claims, the description of the facts, and the evidence presented by the complainant. In US–Zeroing (Korea), the United States did just that. We explore whether Korea obtained any additional benefit by having an easy case. We identified some small benefits at the preparation stage of the case arising from the favourable precedents and shorter time frames only at the Panel stage. There were, however, some additional costs for the complainant stemming from the Panel's reasoning when it addressed case law. In our opinion, benefits were few. Korea was obliged in any case to engage in two years of multilateral procedures before three old measures, which were not defended by the defendant, were revoked.
Synkopen auf einem universitären Notfall – ist die ambulante Behandlung der Patienten sicher?
Authors: Haltmeier Simone , Lindner Gregor , Exadaktylos Aristomenis Konstantinos , Haberkern Monika
Published: April 2013

Synkopen sind ein häufiger Einweisungsgrund auf einer Notfallstation. Zwei Scoring-Methoden sind geprüft bezüglich klinischer Entscheidungsfindung, Indikation zu weiterführender Diagnostik und Hospitalisation. Ziel der Arbeit war die Qualitätskontrolle bei ambulanter Behandlung von Synkope-Patienten auf unserer universitären Notfallstation. 200 konsekutive Synkopen-Patienten wurden dokumentiert, bei 109 Patienten mit telefonischem Follow-up über zwei Jahre. Die Entscheidung zu ambulanter oder stationärer Behandlung oblag dem Dienst-Oberarzt. Die Altersverteilung im Patientenkollektiv war biphasisch, bis 25-jährig waren es vor allem Frauen, in der 6. bis 8. Lebensdekade überwiegend Männer. Die Ursache der Synkopen blieb diagnostisch weitgehend ungeklärt, mit benignem Verlauf für die nachkontrollierten Fälle. Selten wurde eine neurologische (n=3) respektive eine kardiale Ursache (n=5) gefunden, mit therapeutischer Konsequenz.
Injektionstechnik peripherer Gelenke und periartikulärer Strukturen aus der Sicht klinisch tätiger Rheumatologen
Authors: Tamborrini Giorgio , Krebs Andreas
Published: April 2013

Diagnostische und therapeutische Gelenksinjektionen und Injektionen periartikulärer Strukturen (z.B. Sehnenscheiden) werden im klinischen Alltag häufig durchgeführt. In dieser Arbeit fassen wir aktuelle Richtlinien von Injektionstechniken zusammen, wie sie auch in den Workshops der letztjährigen «Medidays» am Universitätsspital Zürich vorgestellt wurden. Im Weiteren wird auf Medikamente, Komplikationen, unerwünschte Wirkungen und Kontraindikationen eingegangen. Ein besonderes Augenmerk legen wir auf die Indikationen und Technik ultraschallgesteuerter Injektionen am Bewegungsapparat.
Relationships Between Brain and Body Temperature, Clinical and Imaging Outcomes after Ischemic Stroke
Authors: Karaszewski Bartosz , Carpenter Trevor K , Thomas Ralph GR , Armitage Paul A , Lymer Georgina Katherine S , Marshall Ian , Dennis Martin S , Wardlaw Joanna M
Published: April 2013

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using 1 H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17 hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P = 0.03) but both were equally elevated by 5 days;both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome;in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature;that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes.
Transglutaminase is a Therapeutic Target for Oxidative Stress, Excitotoxicity and Stroke: A new Epigenetic Kid on the Cns Block
Authors: Basso Manuela , Ratan Rajiv R
Published: April 2013

Transglutaminases (TGs) are multifunctional, calcium-dependent enzymes that have been recently implicated in stroke pathophysiology. Classically, these enzymes are thought to participate in cell injury and death in chronic neurodegenerative conditions via their ability to catalyze covalent, nondegradable crosslinks between proteins or to incorporate polyamines into protein substrates. Accumulating lines of inquiry indicate that specific TG isoforms can shuttle into the nucleus when they sense pathologic changes in calcium or oxidative stress, bind to chromatin and thereby transduce these changes into transcriptional repression of genes involved in metabolic or oxidant adaptation. Here, we review the evidence that supports principally a role for one isoform of this family, TG2, in cell injury and death associated with hemorrhagic or ischemic stroke. We also outline an evolving model in which TG2 is a critical mediator between pathologic signaling and epigenetic modifications that lead to gene repression. Accordingly, the salutary effects of TG inhibitors in stroke may derive from their ability to restore homeostasis by removing inappropriate deactivation of adaptive genetic programs by oxidative stress or extrasynaptic glutamate receptor signaling.
New insights into the catalytic mechanism of histidine phosphatases revealed by a functionally essential arginine residue within the active site of the Sts phosphatases
Authors: San Luis Boris , Nassar Nicolas , Carpino Nick
Published: April 2013

Sts (suppressor of T-cell receptor signalling)-1 and Sts-2 are HPs (histidine phosphatases) that negatively regulate TCR (T-cell receptor) signalling pathways, including those involved in cytokine production. HPs play key roles in such varied biological processes as metabolism, development and intracellular signalling. They differ considerably in their primary sequence and substrate specificity, but possess a catalytic core formed by an invariant quartet of active-site residues. Two histidine and two arginine residues cluster together within the HP active site and are thought to participate in a two-step dephosphorylation reaction. To date there has been little insight into any additional residues that might play an important functional role. In the present study, we identify and characterize an additional residue within the Sts phosphatases (Sts-1 Arg383 or Sts-2 Arg369) that is critical for catalytic activity and intracellular function. Mutation of Sts-1 Arg383 to an alanine residue compromises the enzyme's activity and renders Sts-1 unable to suppress TCR-induced cytokine induction. Of the multiple amino acids substituted for Arg383, only lysine partially rescues the catalytic activity of Sts-1. Although Sts-1 Arg383 is conserved in all Sts homologues, it is only conserved in one of the two sub-branches of HPs. The results of the present study highlight an essential role for Sts-1 phosphatase activity in regulating T-cell activation and add a new dimension of complexity to our understanding of HP catalytic activity.
Surface-termination-dependent Pd bonding and aggregation of nanoparticles on LaFeO3 (001)
Authors: Li Baihai , Katz Michael B. , Zhang Qiuju , Chen Liang , Graham George W. , Pan Xiaoqing
Published: April 2013

The bonding and morphology of Pd clusters deposited on the LaO- and FeO2-terminated LaFeO3 (001) surface were studied using periodic density functional methods together with scanning transmission electron microscopy. We show that Pd tends to aggregate to three-dimensional (3D) clusters on both terminations since the Pd-Pd cohesive energy is larger than the Pd-LaFeO3 adhesive energy. However, from the kinetic point of view, Pd migration on the LaO termination is facile, while stronger interactions between Pd and the FeO2 termination significantly hinder the migration of Pd. Furthermore, molecular dynamics simulations demonstrate that Pd would agglomerate into 3D metallic and PdOx particles on the LaO and FeO2 terminations, respectively, and hint at the possibility of partial penetration of the PdOx particles into the surface, as observed experimentally.
Computational fluid dynamics model development on transport phenomena coupling with reactions in intermediate temperature solid oxide fuel cells
Authors: Yang Chao , Yang Guogang , Yue Danting , Yuan Jinliang , Sunden Bengt
Published: April 2013

A 3D model is developed to describe an anode-supported planar solid oxide fuel cell (SOFC), by Ansys/Fluent evaluating reactions including methane steam reforming (MSR)/water-gas shift (WGSR) reactions in thick anode layer and H2-O2/CO-O2 electrochemical reactions in anode active layer, coupled with heat, mass species, momentum, and ion/electron charges transport processes in SOFC. The predicted results indicate that electron/ion exchange appears in the very thin region in active layers (0.018 mm in anode and 0.01 mm in cathode), based on three phase boundary, operating temperature and concentration of reactants (mainly H2). Active polarization happening in active layers dominates over concentration and ohmic losses. High gradient of current density exists near interface between electrode and solid conductor due to the block by gas channel. It is also found the reaction rates of MSR and WGSR along main flow direction and cell thickness direction decrease due to low concentration of fuel (CH4) caused by mass consumption. With increasing operating temperature from 978 K to 1088 K, the current density and the reaction rate of MSR are increased by 10.8% and 5.4%, respectively. While ion current density is 52.9% higher than in standard case, and H2 is consumed by 5.1% more when ion conductivity is doubled. CO-O2 has been considered in charge transfer reaction in anode active layer and it is found that the current density and species distributions are not sensitive, but WGSR reaction will be forced backwards to supply more CO for CO-O2 electrochemical reaction.
Correlation between site preference and magnetic characteristics of self assembled strontium ferrite dot array on functionalized multi-walled carbon nanotubes
Authors: Ghasemi Ali , Sepelak Vladimir , Liu Xiaoxi , Morisako Akimitsu
Published: April 2013

In this research work, ferrite nanoparticles with composition of SrFe12−x(Ni0.5Co0.5Ti)x/2O19 (x = 0-2.5 in a step of 0.5) were synthesized by a reverse micelle. Multiwalled carbon nanotubes (MWCNT) were also functionalized by employing poly(acrylic acid). Then the ferrite nanoparticles were deposited on the functionalized surface of carbon nanotubes by hetero-coagulation process. The volume percentage of carbon nanotubes was kept constant at 8 vol. % for synthesizing nanocomposites. The site preference of substituted cations in ferrite crystal structure was determined by 57Fe Mössbauer spectroscopy. It was proved that the substituted cations were distributed in 12 k crystallographic sites. The morphology of ferrite dot array on carbon nanotubes was studied by field emission scanning electron microscopy (FESEM). Quantum Device MPMS-5S SQUID magnetometer was used to probe the variation of magnetization with applied magnetic field. It was found that with an increase in substitution content, the saturation of magnetization and coercivity decrease.
Counter-propagating dual-trap optical tweezers based on linear momentum conservation
Authors: Ribezzi-Crivellari M. , Huguet J. M. , Ritort F.
Published: April 2013

We present a dual-trap optical tweezers setup which directly measures forces using linear momentum conservation. The setup uses a counter-propagating geometry, which allows momentum measurement on each beam separately. The experimental advantages of this setup include low drift due to all-optical manipulation, and a robust calibration (independent of the features of the trapped object or buffer medium) due to the force measurement method. Although this design does not attain the high-resolution of some co-propagating setups, we show that it can be used to perform different single molecule measurements: fluctuation-based molecular stiffness characterization at different forces and hopping experiments on molecular hairpins. Remarkably, in our setup it is possible to manipulate very short tethers (such as molecular hairpins with short handles) down to the limit where beads are almost in contact. The setup is used to illustrate a novel method for measuring the stiffness of optical traps and tethers on the basis of equilibrium force fluctuations, i.e., without the need of measuring the force vs molecular extension curve. This method is of general interest for dual trap optical tweezers setups and can be extended to setups which do not directly measure forces.
Optical absorption and emission of silicon nanocrystals: From single to collective response
Authors: Guerra Roberto , Cigarini Francesco , Ossicini Stefano
Published: April 2013

We report on the possibility of describing the absorption and emission characteristics of an ensemble of silicon nanocrystals (NCs) with realistic distributions in the NC size, by the sum of the responses of the single NCs. The individual NC responses are evaluated by means of ab initio theoretical calculations and the summation is performed by taking into account the trend of the optical properties as a function of NC size and oxidation degree. The comparison with experimental results shows a nice matching of the spectra, also without any tuning of the parameters. Finally, the possibility of adapting the model in order to reproduce the experimental data is explored and discussed.
Susceptibility of Fe atoms in Cu clusters
Authors: Zhang Rui , George Tom A. , Kharel Parashu , Skomski Ralph , Sellmyer D. J.
Published: April 2013

By putting a Kondo system of limited dimension inside an insulating matrix, the Kondo screening cloud is confined by the size of the system. This allows us to distinguish the bulk and nano-particle behaviors of such system. We have investigated the magnetic properties of 0.3 at. % Fe-doped Cu clusters with dimensions less than 20 nm embedded in a SiO2 matrix. The magnetic measurements are consistent with the Kondo interaction, and net antiferromagnetic Ruderman-Kittel-Kasuya-Yosida (RKKY) interactions between several Fe atoms in one cluster are estimated to have a very small effect. To understand the low-temperature susceptibility reduction, we compare Brillouin functions with exact quantum-mechanical solutions for interacting spin-1 particles and with the Kondo predictions for confined nanoparticles.
Interfacial tension in oil–water–surfactant systems: On the role of intra-molecular forces on interfacial tension values using DPD simulations
Authors: Deguillard E. , Pannacci N. , Creton B. , Rousseau B.
Published: April 2013

We have computed interfacial tension in oil–water–surfactant model systems using dissipative particle dynamics (DPD) simulations. Oil and water molecules are modelled as single DPD beads, whereas surfactant molecules are composed of head and tail beads linked together by a harmonic potential to form a chain molecule. We have investigated the influence of the harmonic potential parameters, namely, the force constant K and the equilibrium distance r0, on the interfacial tension values. For both parameters, the range investigated has been chosen in agreement with typical values in the literature. Surprisingly, we observe a large effect on interfacial tension values, especially at large surfactant concentration. We demonstrate that, due to a subtle balance between intra-molecular and inter-molecular interactions, the local structure of surfactants at the oil–water interface is modified, the interfacial tension is changed and the interface stability is affected.
Step tunneling enhanced asymmetry in asymmetric electrode metal-insulator-insulator-metal tunnel diodes
Authors: Alimardani N. , Conley J. F.
Published: April 2013

The impact of nanolaminate insulator tunnel barriers on asymmetric metal workfunction metal-insulator-insulator-metal (MIIM) devices is investigated. We demonstrate experimentally that bilayer insulators introduce additional asymmetry and can be arranged to either enhance or oppose the asymmetry induced by the asymmetric workfunction electrodes. It is also shown that step tunneling can dominate the I-V asymmetry of M1IIM2 diodes. By combining bilayer tunnel barriers with the standard approach of asymmetric metal electrodes, we are able to achieve low voltage asymmetry and non-linearity exceeding both that of standard single layer asymmetric electrode metal-insulator-metal devices as well as symmetric electrode M1I1I2M1 devices.
Cleanliness control and management of gearbox lubrication system in wind turbine generator
Authors: Zhang Meixiang , Yuan Liao Zhi , Farooq Kal
Published: April 2013

Wind turbine gearbox is one of the most expensive and critical components of the wind turbine generator system. Due to the extreme operating conditions encountered in the gearbox, there is little room for compromises, especially with the performance of the lubrication system. Gearbox lubricating fluid is one of the most important elements of the system—it is analogous to the blood in human body, performing key functions, which in the case of gearbox are maintaining proper lubricity and film thickness between the moving surfaces, heat absorption and its dissipation, suspension and transportation of the particulate debris, prevention of abrasion and corrosion, etc., in the lubrication system. Therefore, the optimum cleanliness level and health of the lubricating fluid is essential for satisfactory performance and service life of the wind turbine gearbox. The paper discusses the cleanliness control and management of the gearbox lubrication system. Examples of filtration related issues experienced in the field are also discussed.
External ring-cavity quantum cascade lasers
Authors: Malara Pietro , Blanchard Romain , Mansuripur Tobias S. , Wojcik Aleksander K. , Belyanin Alexey , Fujita Kazuue , Edamura Tadataka , Furuta Shinichi , Yamanishi Masamichi , de Natale Paolo , Capasso Federico
Published: April 2013

An external ring-cavity quantum cascade laser (QCL) is demonstrated. Gain competition between the clockwise and anticlockwise ring-cavity modes results in a transition from bidirectional to directional emission as current is increased. In the directional regime, spatial hole burning (SHB) is suppressed, and the spectrum evolves to a single longitudinal mode, in contrast with the multimode spectrum of a comparable Fabry-Pérot QCL. The absence of SHB and the long path-length of the external cavity make this laser an excellent candidate for active mode-locking and high-sensitivity spectroscopic applications in the mid-infrared. A proof-of-principle intracavity absorption spectroscopic detection of water vapor is demonstrated.
Evaluation of impedance spectra of ionic-transport materials by a random-walk approach considering electrode and bulk response
Authors: Patil D. S. , Shimakawa K. , Zima V. , Macak J. , Wagner T.
Published: April 2013

Analysis of impedance spectra by a random-walk approach is proposed for the study of ionic-transport materials with a silver-containing chalcogenide glass as a case example. Through a full analysis of complex impedance spectra including the electrode polarization effect, some important physical parameters, such as the number of mobile ions in bulk and interface regions, the diffusion coefficient, etc., are extracted without using the conventional equivalent electric circuit analysis. A detailed discussion on electrode polarization, which is highly dependent on signal amplitude, is also presented.
Characterization of density-of-states and parasitic resistance in a-InGaZnO thin-film transistors after negative bias stress
Authors: Jo Chunhyung , Jun Sungwoo , Kim Woojoon , Hur Inseok , Bae Hagyoul , Choi Sung-Jin , Hwan Kim Dae , Myong Kim Dong
Published: April 2013

Instability mechanism of amorphous InGaZnO thin-film transistors under negative bias stress (NBS) was investigated. After strong NBS stress, we observed a negligible change in the subthreshold swing which is strongly dependent on the subgap density-of-states (DOS). On the other hand, there was substantial increase in the drain current at above-threshold operation. Therefore, the dominant mechanism of the NBS-induced instability is investigated not to be a change in the subgap DOS but a change in the parasitic resistance caused by the reduced Schottky barrier of the metal contacts. This was verified by the extracted source/drain resistance and Technology Computer-Aided Design simulation.
Multiphoton upconversion in rare earth doped nanocrystals for sub-diffractive microscopy
Authors: Caillat L. , Hajj B. , Shynkar V. , Michely L. , Chauvat D. , Zyss J. , Pellé F.
Published: April 2013

A major bottleneck in microscopic imaging is the limited lateral resolution due to the diffraction of light. To overcome this limit, here we demonstrate the upconversion process in rare earth doped nanoparticles (RE:NPs), which may serve as an original fluorescence-source mechanism. RE:NPs have been reported to serve as efficient bio-labels for cellular and small animal imaging. In this work, we demonstrate that non-linearity of upconversion allows achieving high lateral resolution in the images using multiphoton microscopy, demonstrating significant improvement in lateral resolution, using low pumping laser power. This new technique may serve as another approach for high-resolution optical imaging.
Kinetic arrest related to a first-order ferrimagnetic to antiferromagnetic transition in the Heusler compound Mn2PtGa
Authors: Nayak Ajaya K. , Nicklas Michael , Shekhar Chandra , Felser Claudia
Published: April 2013

We report a magnetization study of the Heusler compound Mn2PtGa that shows the existence of a magnetic-glass state. Mn2PtGa shows a first-order ferromagnetic (FM)/ferrimagnetic (FI) to antiferromagnetic (AFM) transition in contrast to the martensitic structural transition observed in several Heusler alloys. The kinetic arrest of this first-order FM (FI) to AFM transition leads to the observed magnetic-glass behavior. We show that the strength of the applied magnetic field, which is the primary parameter to induce the magnetic-glass state, is also responsible for the stability of the supercooled FM (FI) phase in time.
Mode interference and radiation leakage in a tapered parallel plate waveguide for terahertz waves
Authors: Mueckstein R. , Navarro-Cía M. , Mitrofanov O.
Published: April 2013

To exploit tapered parallel plate waveguides for broadband terahertz (THz) spectroscopy, the impact of the waveguide geometry on transmission of terahertz pulses is investigated experimentally. We find that the approximation of single transverse electro-magnetic mode propagation is insufficient for describing the observed behavior. The TE02 mode plays a particularly important role. The mode composition, however, can be controlled by the gap between the waveguide plates, which affects the main loss mechanism, radiation leakage, and group velocity for the TE02 mode. Balancing the waveguide loss and coupling efficiencies results in an optimal gap for the tapered waveguide.
Fluorescence enhancement by a SiO2-based monolithic waveguide structure for biomolecular detection
Authors: Nomura Ken-ichi , Lakshmipriya Thangavel , Fukuda Nobuko , Wang Xiaomin , Fujimaki Makoto
Published: April 2013

We have developed a fluorescence enhancement system for biomolecular detection using a monolithic waveguide sensing plate. The plate consists of a thermally grown amorphous SiO2 layer, a Si single-crystal layer, and bulk amorphous SiO2. Waveguide-mode excitation in this plate produces an enhanced electric field on the plate surface, and therefore, signals from analyte-labeling fluorescent dyes are enhanced. In the present paper, we elucidate the impact of the system from viewpoints of the electric field enhancement factor calculated numerically and the analysis of the limit of detection estimated from experimental results. Optimal layer thicknesses of the plates to achieve the highest sensitivity are also discussed. Further, an interesting phenomenon that accompanied the waveguide-mode excitation, namely, photoluminescence from the amorphous SiO2 layer itself, is also reported.
The growth of high quality GaAsSb and type-II InGaAs/GaAsSb superlattice structure
Authors: Miura K. , Iguchi Y. , Tsubokura M. , Kawamura Y.
Published: April 2013

The effects of growth temperature and V/III flux ratio on the GaAsSb crystalline quality were studied. Phase separation was suppressed within a narrow window of growth temperature. 1-μm-thick GaAsSb layers which exhibited single peaks in X-ray diffraction (XRD) measurement were successfully obtained grown at the optimum temperature. XRD and photoluminescence (PL) measurements revealed that V/III flux ratio also has an optimum value. It was found that the type-II InGaAs/GaAsSb superlattice with GaAsSb grown at the optimized growth condition seems to have an excellent optical property, because the PL peak energy exhibited peculiar dependence on temperature suggesting transition between the conduction band of InGaAs and the valance band of GaAsSb.
Thermal properties of microscale inorganic light-emitting diodes in a pulsed operation
Authors: Li Yuhang , Shi Yan , Song Jizhou , Lu Chaofeng , Kim Tae-il , Rogers John A. , Huang Yonggang
Published: April 2013

Light-emitting diodes (LEDs) in a pulsed operation offer combined characteristics in efficiency, thermal management, and communication, which make them attractive for many applications such as backlight unit, optical communication, and optogenetics. In this paper, an analytic model, validated by three dimensional finite element analysis and experiments, is developed to study the thermal properties of micro-scale inorganic LEDs (μ-ILED) in a pulsed operation. A simple scaling law for the μ-ILED temperature after saturation is established in terms of the material and geometrical parameters of μ-ILED systems, peak power, and duty cycle. It shows that the normalized maximum temperature increase only depends on two non-dimensional parameters: normalized μ-ILED area and duty cycle. This study provides design guidelines for minimizing adverse thermal effects of μ-ILEDs.
Reduction of modal length using Josephson junction array confined cavity
Authors: Wang Jyh-Yang , Liou Saxon , Chang Yu-Cheng , Lee Teik-Hui , Chen Kuan-Wen , Lin Ming-Chou , Wu Cen-Shawn , Kuo Watson , Chen ChiiDong
Published: April 2013

We propose an architecture in which the coupling between a cavity and superconducting qubits is enhanced by reducing the cavity modal length. The cavity is connected to outside transmission lines at the both ends by two short Josephson junction arrays. The latter plays a role of distributed reflector, which can provide an arbitrary negative phase to the reflected wave below its photonic bandgap. With this phase contribution from the Josephson junction arrays, we show, in the context of Fabry-Perot resonance, that the modal length can be 2 orders shorter than the wavelength.
Experiments on unfired masonry clay bricks mixed with palm fronds and date pits for thermal insulation applications
Authors: Hai Alami Abdul
Published: April 2013

The limited resources on the planet have forced the rethinking of otherwise straightforward methods of building and selection of masonry materials. This research investigates using solid waste materials from the desert area and adding them to a clay matrix, and their effect on the thermal and mechanical properties of the resulting composite. Clay and fronds were mixed with pits of dates arranged horizontally, vertically, at 45° angles and crushed pits were compared to plain clay bricks in terms of mechanical and thermal properties. Although adding crushed pits greatly enhanced the mechanical properties of clay bricks, making them 85% tougher (greater area under the stress-strain diagram) and 15% stronger (ultimate stress), the composite did not display any enhancement in thermal properties, as the thermal conductivity remained in the range typical of sand and clay. Suitable applications for the composite would be as moulded pliable insulating sheets, or as a filler material.
All-silicon Michelson instrument on chip: Distance and surface profile measurement and prospects for visible light spectrometry
Authors: Malak M. , Marty F. , Nouira H. , Vailleau G. , Bourouina T.
Published: April 2013

A miniature Michelson interferometer is analyzed theoretically and experimentally. The fabricated micro-interferometer is incorporated at the tip of a monolithic silicon probe to achieve contactless distance measurements and surface profilometry. For infrared operation, two approaches are studied, based on the use of monochromatic light and wavelength sweep, respectively. A theoretical model is devised to depict the system characteristics taking into account Gaussian beam divergence and light spot size. Furthermore, preliminary results using visible light demonstrate operation of the probe as a visible light spectrometer, despite silicon absorbance, thanks to the micrometer thickness involved in the beam splitter.
Surface potential and interlayer screening effects of few-layer MoS2 nanoflakes
Authors: Li Yang , Xu Cheng-Yan , Zhen Liang
Published: April 2013

We report the interlayer screening effects of ultrathin MoS2 nanoflakes with different thicknesses by measuring their surface potential using Kelvin probe microscope. Surface potential of pristine MoS2 nanoflakes decreased with increasing thickness, while after annealing, the trend was opposite and the screening length became smaller. These results were qualitatively explained by a charge transfer model with the built-in electric field induced by trapped charges. The transport mechanism of MoS2 nanoflakes with different thicknesses was also studied by using conductive atomic force microscopy, and the thermonic emission and Fowler-Nordheim tunneling were effective in the forward bias and reverse bias, respectively.
Single-photon detection efficiency up to 50% at 1310 nm with an InGaAs/InP avalanche diode gated at 1.25 GHz
Authors: Restelli Alessandro , Bienfang Joshua C. , Migdall Alan L.
Published: April 2013

We describe a gated Geiger-mode single-photon avalanche diode (SPAD) detection system in which both gating and avalanche discrimination are implemented by coherent addition of discrete harmonics of the fundamental gate frequency. With amplitude and phase control for each harmonic at the cathode, we form <340 ps bias gates, and with similar control at the anode we cancel the gate transient with >65 dB suppression, allowing avalanche-discrimination thresholds at the anode below 2 mV or <8 fC. The low threshold not only accurately discriminates diminutive avalanches but also achieves usable detection efficiencies with lower total charge, reducing the afterpulse probability and allowing the use of gate pulses that exceed the SPAD breakdown voltage by more than 10 V, both of which increase detection efficiency. With detection efficiency of 0.19 ± 0.01, we measure per-gate afterpulse probability below 6.5 × 10−4 after 3.2 ns, and with detection efficiency of 0.51 ± 0.02 we measure per-gate afterpulse probability below 3.5 × 10−3 after 10 ns.
California spiny lobster (Panulirus interruptus) movement behaviour and habitat use: implications for the effectiveness of marine protected areas
Authors: Withy-Allen Kira R. , Hovel Kevin A.
Published: April 2013

The effectiveness of conservation efforts, including marine protected areas (MPAs), hinges on adequate knowledge of movement patterns, habitat associations and habitat-specific survival rates of mobile organisms. California spiny lobsters (Panulirus interruptus) support commercial and recreational fishing in southern California; however, we lack basic information to determine whether MPAs planned for the region will enhance abundance. Working within and outside a small southern California MPA, we (1) quantified the movement patterns and home ranges of the lobster over two time scales, (2) determined lobster day and night habitat associations and (3) determined habitat-specific predation risk. Lobsters exhibited high site fidelity and small home ranges (geometric mean of 651 m2 and 5912 m2 per week, on the basis of 50% and 95% kernel utilisation distributions, respectively). Lobsters were associated with rocky habitat during the day and with the red algae Plocamium cartilagineum while feeding at night. Relative survival rates of lobsters were high across vegetated and unvegetated habitats at night, and were highest in surfgrass (Phyllopsadix torreyi) habitat during the day. Our results highlight the need to consider how movement patterns vary over short and long time scales, and how habitat use may vary from day to night for nocturnally active species such as lobsters, when planning MPAs.
The mark–recapture method applied to population estimates of a freshwater crab on an alluvial plain
Authors: Carvalho Débora de Azevedo , Collins Pablo Agustín , De Bonis Cristian Javier
Published: April 2013

Mark–recapture methods are a useful population estimation tool, although with many assumptions that cannot always be satisfied for all types of organisms and environments. In the present study, three mark–recapture methods (Petersen, Schnabel and Schumacher–Eschmeyer) were applied in a preliminary trial to estimate the population size of the crab Trichodactylus borellianus and to gain information that would support the use of the methods in the field. The accuracy of these estimates was verified by analysing the percentage of bias, the width of the confidence intervals, and by a chi-square test. The assumptions of equal catchability and closed population were verified, along with assumptions related to the efficiency of marking. The adjusted methodology was applied in a short-term study of a pond on the Paraná floodplain. The results showed that the assumptions were satisfied for both the experimental and field studies. The Schnabel was the most accurate method evaluated in both studies. Although the Schumacher–Eschmeyer method also provided accurate results in the field study, it needed large samples to give reliable estimates. The applicability of these methods depends on the stage of the hydrological cycle. The choice of a short-term research design will ensure that the assumption of a closed population is valid for research of this type on an alluvial plain.