bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental and theoretical characterization of ordered MAX phases Mo2TiAlC2 and Mo2Ti2AlC3
Authors: Anasori Babak , Dahlqvist Martin , Halim Joseph , Moon Eun Ju , Lu Jun , Hosler Brian C. , Caspi El'ad N. , May Steven J. , Hultman Lars , Eklund Per , Rosén Johanna , Barsoum Michel W.
Published: September 2015

Herein, we report on the phase stabilities and crystal structures of two newly discovered ordered, quaternary MAX phases—Mo2TiAlC2 and Mo2Ti2AlC3—synthesized by mixing and heating different elemental powder mixtures of mMo:(3-m)Ti:1.1Al:2C with 1.5 ≤ m ≤ 2.2 and 2Mo: 2Ti:1.1Al:2.7C to 1600 °C for 4 h under Ar flow. In general, for m ≥ 2 an ordered 312 phase, (Mo2Ti)AlC2, was the majority phase; for m < 2, an ordered 413 phase (Mo2Ti2)AlC3, was the major product. The actual chemistries determined from X-ray photoelectron spectroscopy (XPS) are Mo2TiAlC1.7 and Mo2Ti1.9Al0.9C2.5, respectively. High resolution scanning transmission microscopy, XPS and Rietveld analysis of powder X-ray diffraction confirmed the general ordered stacking sequence to be Mo-Ti-Mo-Al-Mo-Ti-Mo for Mo2TiAlC2 and Mo-Ti-Ti-Mo-Al-Mo-Ti-Ti-Mo for Mo2Ti2AlC3, with the carbon atoms occupying the octahedral sites between the transition metal layers. Consistent with the experimental results, the theoretical calculations clearly show that M layer ordering is mostly driven by the high penalty paid in energy by having the Mo atoms surrounded by C in a face-centered configuration, i.e., in the center of the Mn+1Xn blocks. At 331 GPa and 367 GPa, respectively, the Young's moduli of the ordered Mo2TiAlC2 and Mo2Ti2AlC3 are predicted to be higher than those calculated for their ternary end members. Like most other MAX phases, because of the high density of states at the Fermi level, the resistivity measurement over 300 to 10 K for both phases showed metallic behavior.
Extending the path for efficient extreme ultraviolet sources for advanced nanolithography
Authors: Sizyuk Tatyana , Hassanein Ahmed
Published: September 2015

Developing efficient light sources for extreme ultraviolet (EUV) lithography is one of the most important problems of high volume manufacturing (HVM) of the next generation computer chips. Critical components of this technology are continued to face challenges in the demanding performance for HVM. Current investigations of EUV and beyond EUV (BEUV) community are focused on the dual-pulse laser produced plasma (LPP) using droplets of mass-limited targets. Two main objectives as well as challenges in the optimization of these light sources are related to enhancement of the conversion efficiency (CE) of the source and increase components lifetime of the collector optical system. These require significant experimental and computer simulation efforts. These requirements call for fine detail analysis of various plasma physics processes involved in laser target interactions and their effects on source optimization. We continued to enhance our comprehensive HEIGHTS simulation package and upgrade our CMUXE laboratories to study and optimize the efficiency of LPP sources. Integrated modeling and experimental research were done to both benchmark simulation results and to make projections and realistic predictions of the development path for powerful EUVL devices for HVM requirements. We continued the detail analysis of dual-pulse laser systems using various laser wavelengths and delay times between the two pulses. We showed that the efficiency of EUV sources can be improved utilizing the higher harmonics of Nd:YAG laser for the prepulse and the first harmonics for the main pulse, while still having lower efficiency than the combination involving CO2 laser in the range of parameters studied in this case. The differences in optimization process as well as in the source characteristics for two combinations of laser wavelengths were analyzed based on details of atomic and hydrodynamics processes during the evolving plasma plumes.
Breakdown of the Brillouin limit and classical fluxes in rotating collisional plasmas
Authors: Rax J. M. , Fruchtman A. , Gueroult R. , Fisch N. J.
Published: September 2015

The classical collisionless analysis displaying the occurrence of slow and fast rigid body rotation modes in magnetized plasmas is extended to collisional discharges. Collisions speed up the fast mode, slow down the slow one, and break down the classical Brillouin limit. Rigid body rotation has a strong impact on transport, and a collisional radial transport regime, different from the classical Braginskii collisional flux, is identified and analyzed.
Global theory of beta-induced Alfvén eigenmode excited by energetic ions
Authors: Ma Ruirui , Zonca Fulvio , Chen Liu
Published: September 2015

The two-dimensional global stability and mode structures of high-n beta-induced Alfvén eigenmodes excited by energetic ions in tokamaks are examined both analytically and numerically, employing the WKB-ballooning mode representation along with the generalized fishbone like dispersion relation. Here, n≫1 is the toroidal mode number. Our results indicate that (i) the lowest radial bound state corresponds to the most unstable eigenmode, and (ii) the anti-Hermitian contributions due to wave-energetic particle resonance give rise to the twisting radial mode structures.
Quasilinear saturation of the aperiodic ordinary mode streaming instability
Authors: Stockem Novo A. , Yoon P. H. , Lazar M. , Schlickeiser R. , Poedts S. , Seough J.
Published: September 2015

In collisionless plasmas, only kinetic instabilities and fluctuations are effective in reducing the free energy and scatter plasma particles, preventing an increase of their anisotropy. Solar energetic outflows into the interplanetary plasma give rise to important thermal anisotropies and counterstreaming motions of plasma shells, and the resulting instabilities are expected to regulate the expansion of the solar wind. The present paper combines quasilinear theory and kinetic particle-in-cell simulations in order to study the weakly nonlinear saturation of the ordinary mode in hot counter-streaming plasmas with a temperature anisotropy as a follow-up of the paper by Seough et al. [Phys. Plasmas 22, 082122 (2015)]. This instability provides a plausible mechanism for the origin of dominating, two-dimensional spectrum of transverse magnetic fluctuations observed in the solar wind. Stimulated by the differential motion of electron counterstreams the O mode instability may convert their free large-scale energy by nonlinear collisionless dissipation on plasma particles.
Wave-particle interactions with parallel whistler waves: Nonlinear and time-dependent effects revealed by particle-in-cell simulations
Authors: Camporeale Enrico , Zimbardo Gaetano
Published: September 2015

We present a self-consistent Particle-in-Cell simulation of the resonant interactions between anisotropic energetic electrons and a population of whistler waves, with parameters relevant to the Earth's radiation belt. By tracking PIC particles and comparing with test-particle simulations, we emphasize the importance of including nonlinear effects and time evolution in the modeling of wave-particle interactions, which are excluded in the resonant limit of quasi-linear theory routinely used in radiation belt studies. In particular, we show that pitch angle diffusion is enhanced during the linear growth phase, and it rapidly saturates well before a single bounce period. This calls into question the widely used bounce average performed in most radiation belt diffusion calculations. Furthermore, we discuss how the saturation is related to the fact that the domain in which the particles pitch angle diffuses is bounded, and to the well-known problem of 90° diffusion barrier.
Lasing action and extraordinary reduction in long radiative lifetime of type-II GaSb/GaAs quantum dots using circular photonic crystal nanocavity
Authors: Hsu Kung-Shu , Hung Wei-Chun , Chang Chih-Chi , Lin Wei-Hsun , Shih Min-Hsiung , Lee Po-Tsung , Lin Shih-Yen , Chang Shu-Wei , Chang Yia-Chung
Published: September 2015

We demonstrated the lasing action and remarkable reduction in long radiative lifetimes of type-II GaSb/GaAs quantum dots using a circular photonic-crystal nano-cavity with high Purcell factors. The associated enhancement in carrier recombination was surprisingly high and could even surpass type-I counterparts in similar conditions. These phenomena reveal that the type-II sample exhibited extremely low nonradiative recombination so that weak radiative transitions were more dominant than expected. The results indicate that type-II nanostructures may be advantageous for applications which require controllable radiative transitions but low nonradiative depletions.
Visible-blind ultraviolet photodiode fabricated by UV oxidation of metallic zinc on p-Si
Authors: Zhang Dongyuan , Uchida Kazuo , Nozaki Shinji
Published: September 2015

A UV photodiode fabricated by the UV oxidation of a metallic zinc thin film on p-Si has manifested unique photoresponse characteristics. The electron concentration found by the Hall measurement was 3 × 1016 cm−3, and such a low electron concentration resulted in a low visible photoluminescence. UV illumination enhances the oxidation at low temperatures and decreases the concentration of the oxygen vacancies. The I-V characteristic showed a good rectification with a four-order magnitude difference in the forward and reverse currents at 2 V, and its linear and frequency independent C−2–V characteristic confirmed an abrupt pn junction. The photoresponse showed a visible blindness with a responsivity ratio of UV and visible light as high as 100. Such a visible-blind photoresponse was attributed to the optimum thickness of the SiO2 formed on the Si surface during the UV oxidation at 400 °C. A lower potential barrier to holes at the ZnO/SiO2 interface facilitates Fowler-Nordheim tunneling of the photo-generated holes during the UV illumination, while a higher potential barrier to electrons efficiently blocks transport of the photo-generated electrons to the ZnO during the visible light illumination. The presence of oxide resulted in a slow photoresponse to the turn-on and off of the UV light. A detailed analysis is presented to understand how the photo-generated carriers contribute step by step to the photocurrent. In addition to the slow photoresponse associated with the SiO2 interfacial layer, the decay of the photocurrent was found extremely slow after turn-off of the UV light. Such a slow decay of the photocurrent is referred to as a persistent photoconductivity, which is caused by metastable deep levels. It is hypothesized that Zn vacancies form such a deep level, and that the photo-generated electrons need to overcome a thermal-energy barrier for capture. The ZnO film by the UV oxidation at 400 °C was found to be rich in oxygen and deficient in zinc.
Electronic and magnetic transitions in perovskite SrRu1-xIrxO3 thin films
Authors: Biswas Abhijit , Lee Yong Woo , Jeong Yoon Hee
Published: September 2015

We have investigated the electronic and magnetic properties of perovskite SrRu1−xIrxO3 (0.0≤ x ≤ 0.25) thin films grown by pulsed laser deposition on atomically flat (001) SrTiO3 substrates. SrRuO3 has the properties of a ferromagnetic metal (resistivity ρ ∼ 200 μΩ · cm at T = 300 K) with Curie temperature TC ∼ 150 K. Substituting Ir (5d5+) for Ru (4d4+) in SrRuO3, films (0.0 ≤ x ≤ 0.20) showed fully metallic behavior and ferromagnetic ordering, although ρ increased and the ferromagnetic TC decreased. Films with x = 0.25 underwent the metal-to-insulator transition (TMIT∼75 K) in ρ, and spin-glass-like ordering (TSG∼45 K) with the elimination of ferromagnetic long-range ordering caused by the electron localization at the substitution sites. In ferromagnetic films (0.0 ≤ x ≤ 0.20), ρ increased near-linearly with T at T > TC, but in paramagnetic film (x = 0.25) ρ increased as T3/2 at T > TMIT. Moreover, observed spin-glass-like (TSG) ordering with the negative magnetoresistance at T < TMIT in film with x = 0.25 validates the hypothesis that (Anderson) localization favors glassy ordering at amply disorder limit. These observations provide a promising approach for future applications and of fundamental interest in 4d and 5d mixed perovskites.
Energy resolution and efficiency of phonon-mediated kinetic inductance detectors for light detection
Authors: Cardani L. , Colantoni I. , Cruciani A. , Di Domizio S. , Vignati M. , Bellini F. , Casali N. , Castellano M. G. , Coppolecchia A. , Cosmelli C. , Tomei C.
Published: September 2015

The development of sensitive cryogenic light detectors is of primary interest for bolometric experiments searching for rare events like dark matter interactions or neutrino-less double beta decay. Thanks to their good energy resolution and the natural multiplexed read-out, Kinetic Inductance Detectors (KIDs) are particularly suitable for this purpose. To efficiently couple KIDs-based light detectors to the large crystals used by the most advanced bolometric detectors, active surfaces of several cm2 are needed. For this reason, we are developing phonon-mediated detectors. In this paper, we present the results obtained with a prototype consisting of four 40 nm thick aluminum resonators patterned on a 2 × 2 cm2 silicon chip, and calibrated with optical pulses and X-rays. The detector features a noise resolution σE = 154 ± 7 eV and an (18 ± 2)% efficiency.
Low-frequency noise properties in Pt-indium gallium zinc oxide Schottky diodes
Authors: Zhang Jiawei , Zhang Linqing , Ma Xiaochen , Wilson Joshua , Jin Jidong , Du Lulu , Xin Qian , Song Aimin
Published: September 2015

The low-frequency noise properties of Pt-indium gallium zinc oxide (IGZO) Schottky diodes at different forward biases are investigated. The IGZO layer and Pt contact were deposited by RF sputtering at room temperature. The diode showed an ideality factor of 1.2 and a barrier height of 0.94 eV. The current noise spectral density exhibited 1/f behavior at low frequencies. The analysis of the current dependency of the noise spectral density revealed that for the as-deposited diode, the noise followed Luo's mobility and diffusivity fluctuation model in the thermionic-emission-limited region and Hooge's empirical theory in the series-resistance-limited region. A low Hooge's constant of 1.4 × 10−9 was found in the space-charge region. In the series-resistance-limited region, the Hooge's constant was 2.2 × 10−5. After annealing, the diode showed degradation in the electrical performance. The interface-trap-induced noise dominated the noise spectrum. By using the random walk model, the interface-trap density was obtained to be 3.6 × 1015 eV−1 cm−2. This work provides a quantitative approach to analyze the properties of Pt-IGZO interfacial layers. These low noise properties are a prerequisite to the use of IGZO Schottky diodes in switch elements in memory devices, photosensors, and mixer diodes.
Field effect tuning of microwave Faraday rotation and isolation with large-area graphene
Authors: Skulason Helgi S. , Sounas Dimitrios L. , Mahvash Farzaneh , Francoeur Sebastien , Siaj Mohamed , Caloz Christophe , Szkopek Thomas
Published: September 2015

We have demonstrated field effect tuning of microwave frequency Faraday rotation in magnetically biased large-area graphene in a hollow circular waveguide isolator geometry. Oxidized intrinsic silicon was used as a microwave transparent back-gate for large-area graphene devices. A 26 dB modulation of isolation in the K-band was achieved with a gate voltage modulation of 10 V corresponding to a carrier density modulation of 7×1011/cm2. We have developed a simple analytical model for transmission and isolation of the structure. Field effect modulation of Faraday rotation can be extended to other two dimensional electronic systems and is anticipated to be useful for gate voltage controlled isolators, circulators, and other non-reciprocal devices.
Quantitative first-principles theory of interface absorption in multilayer heterostructures
Authors: Hachtel Jordan A. , Sachan Ritesh , Mishra Rohan , Pantelides Sokrates T.
Published: September 2015

The unique chemical bonds and electronic states of interfaces result in optical properties that are different from those of the constituting bulk materials. In the nanoscale regime, the interface effects can be dominant and impact the optical response of devices. Using density functional theory (DFT), the interface effects can be calculated, but DFT is computationally limited to small systems. We describe a method to combine DFT with macroscopic methodologies to extract the interface effect on absorption in a consistent and quantifiable manner. The extracted interface effects are an independent parameter and can be applied to more complicated systems. We demonstrate, using NiSi2/Si heterostructures, that by varying the relative volume fractions of interface and bulk, we can tune the spectral range of the heterostructure absorption.
Effect of solar area concentration ratio on performance of a conventional solar still with air humidification-dehumidification
Authors: Al-Otoom A. Y. , Tamimi A. I. , Abandeh S. Z.
Published: September 2015

The high demand for drinking water increased the need to develop new economic methods for water desalination. Conventional solar stills suffer from latent heat losses resulting from water-vapor condensation on the inner surface of the glazing. Using open humidification-dehumidification process with conventional solar stills is a potential area in water desalination nowadays. Integrating a vertical duct to the still for generating a natural draft and solar-air preheater improved its performance. The effect of the solar area concentration ratio on the still performance with heater was studied thoroughly compared to no heater as a reference. Using a condenser in the duct prevents latent heat losses on the inner surface of the glazing and utilizes it to preheat the feed water. This arrangement improved the still productivity. A model was generated to describe the efficiency of the system using three area concentration ratios: 0.5, 0.625, and 0.75. The results showed that the still productivity increased proportionally with the area concentration ratio with average productivity of 5.5 l m−2 day.
Wave excitation by nonlinear coupling among shear Alfvén waves in a mirror-confined plasma
Authors: Ikezoe R. , Ichimura M. , Okada T. , Hirata M. , Yokoyama T. , Iwamoto Y. , Sumida S. , Jang S. , Takeyama K. , Yoshikawa M. , Kohagura J. , Shima Y. , Wang X.
Published: September 2015

A shear Alfvén wave at slightly below the ion-cyclotron frequency overcomes the ion-cyclotron damping and grows because of the strong anisotropy of the ion temperature in the magnetic mirror configuration, and is called the Alfvén ion-cyclotron (AIC) wave. Density fluctuations caused by the AIC waves and the ion-cyclotron range of frequencies (ICRF) waves used for ion heating have been detected using a reflectometer in a wide radial region of the GAMMA 10 tandem mirror plasma. Various wave-wave couplings are clearly observed in the density fluctuations in the interior of the plasma, but these couplings are not so clear in the magnetic fluctuations at the plasma edge when measured using a pick-up coil. A radial dependence of the nonlinearity is found, particularly in waves with the difference frequencies of the AIC waves; bispectral analysis shows that such wave-wave coupling is significant near the core, but is not so evident at the periphery. In contrast, nonlinear coupling with the low-frequency background turbulence is quite distinct at the periphery. Nonlinear coupling associated with the AIC waves may play a significant role in the beta- and anisotropy-limits of a mirror-confined plasma through decay of the ICRF heating power and degradation of the plasma confinement by nonlinearly generated waves.
Sire breed and sex effects on the fatty acid composition and content of heart, kidney, liver, adipose and muscle tissues of purebred and first-cross prime lambs
Authors: Malau-Aduli A. E. O. , Holman B. W. B. , Kashani A. , Nichols P. D.
Published: September 2015

The present study investigated sire breed and sex effects on the fatty acid (FA) composition and content of subcutaneous adipose, Longissimus lumborum muscle, kidney, heart and liver tissues in prime lambs. Tissue samples were taken from 40 Merino ewe and wether lambs sired by Black Suffolk, Dorset, Merino and White Suffolk rams. FA proportion (% total FA) showed significant variations. The highest relative concentrations of total saturated fatty acid (SFA) were in adipose tissue, concentrations of monounsaturated fatty acids (MUFA) were highest in muscle and concentrations of two nutritionally important omega-3 long-chain (≥C20) polyunsaturated FA (LC-PUFA), namely, eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic (DHA, 22:6n-3) acids, were highest in kidney tissue (10.4% total FA), as were those of total PUFA in heart tissue. Sire breed variations in kidney for 18:3n-3, 22:6n-3, 16:0, 16:1n-7c and total omega-6 PUFA, and in muscle for 17:0, 18:3n-3 and 18:1n-7 were evident. Adipose tissue concentrations of 16:1n-9c, 17 : 0 and 16 : 0 in the heart and liver were affected by sire breed. The effect of sex on most major individual FA and totals of SFA, MUFA, omega-3 and omega-6 PUFA were, for the most part, negligible. These results suggest that consumption of lamb heart, liver and kidney can prove beneficial because of their high total PUFA composition and, in particular, concentration (mg/100 g) of key health-benefitting n-3 LC-PUFA. The fact that there were significant sire-breed variations implies that the manipulation of FA composition and content of lamb products and their associated nutritional and sensory qualities will need a deliberate breeding management that matches product goals with available sire breeds.
Selenium characterisation of the Portuguese bread-wheat archival collection
Authors: Galinha Catarina , Pacheco Adriano M. G. , Freitas Maria do Carmo , Costa Ana Rita P. , Pinheiro Nuno M. B. , Maçãs Benvindo , Almeida Ana Sofia , Wolterbeek Hubert T.
Published: September 2015

Following the first morphological and taxonomic inventory of Portuguese wheat in 1933, an archival collection of representative varieties has been maintained, replanted and documented by the National Institute of Agricultural and Veterinary Research (INIAV), specifically by its division formerly known as the National Station for Plant Improvement (ENMP-Elvas, now INIAV-Elvas). The INIAV-Elvas wheat collection has always been an invaluable asset in studies of agronomic and/or genetic development of wheat lines, as well as providing a frame of reference for the nutritional evolution of Portuguese wheat crops. This work addresses the status of selenium (Se) in a pool of 46 accessions of bread wheat. Special attention is paid to the (low) levels of Se, for which wheat acts as an important source in human diets, with a view to curbing its deficiency in Portuguese cultivars through biofortification strategies. All grain samples were irradiated at the Portuguese Research Reactor, and total Se was determined through cyclic neutron activation analysis. Our results indicate that the best candidates for an improvement of Se contents in mature grains are cvv. Ideal, Ribeiro (b) and Ribeiro (a), and the worst candidates are cvv. Restauração, Galego Rapado and Rieti.
Environmental control of dimethylsulfoxide (DMSO) cycling under ocean acidification
Authors: Zindler-Schlundt Cathleen , Lutterbeck Hannah , Endres Sonja , Bange Hermann W.
Published: September 2015

Environmental context Ocean acidification affects marine algae and bacteria, which can produce climate active trace gases such as methane or dimethylsulfide from marine dimethylsulfoxide. We conducted field experiments simulating future ocean acidification, and showed that dimethylsulfoxide concentrations decreased with increasing acidification. Less dimethylsulfoxide in the future can affect climate by influencing the concentration of methane and dimethylsulfide. Abstract Ongoing ocean acidification (OA), caused by continuous anthropogenic CO2 emissions, seems to decrease the concentrations of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) in the surface oceans. This might have consequences for future climate due to changes in formation and growth of atmospheric sulfate aerosols formed from DMS. However, the effect of OA on dimethylsulfoxide (DMSO), another intermediate of the DMS pathway and a potential precursor of oceanic methane, is unknown. Therefore, we investigated the effect of OA on the DMSO concentrations in a mesocosm study conducted in a Norwegian fjord in spring 2011. Dissolved and particulate DMSO concentrations (DMSOd/p) decreased with pH during the course of the experiment. Temperature correlated inversely with DMSOd concentrations during the first week of the experiment, reflecting the influence of temperature dependent biological activities on DMSOd pathways. Furthermore, DMSOd increased with the cell abundance of heterotrophic bacteria, cryptophytes, and the cyanobacterium Synechococcus sp. Nitrate availability influenced the distribution of cryptophytes and Synechococcus sp. in the same way as DMSOd, indicating again a possible link between these phytoplankton taxa and DMSOd. We conclude that ongoing OA may lead to decreasing DMSO concentrations in the surface ocean that, in turn, might affect the oceanic distributions of DMS and methane.
Comprehension of television news signed language interpreters
Authors: Wehrmeyer Ella
Published: September 2015

This questionnaire-based study evaluates interpretations of TV news broadcasts into South African Sign Language from the perspective of 360 adult Deaf respondents, who identify factors hindering comprehension. Methodologically, findings are based on both open-ended and closed questions. The sources of difficulty identified, together with viewer assessments of current interpreting services and viewer expectancy norms, are explored in relation to the profile of the Deaf target audience represented by the study sample. Despite potentially low literacy levels, the study found a stronger stated preference for subtitles than for signed interpretation. The limited size of the signed language screen inset and the type of signed language used by the interpreters were found to be the main factors limiting comprehension; to a lesser extent, problems can also be related to various features of the interpreters’ performance (facial expression, mouthing, sign articulation and general language proficiency), viewers’ insufficient background knowledge and signing skills, the difficulty of dividing attention between different forms of visual input, as well as the positioning of the screen inset showing the interpreter. The cultural and linguistic heterogeneity of the South African Deaf community poses a further challenge to interpreters. Recommendations for both interpreting practice and further research emerge from the discussion.
Children’s identities constructions and the “Mehrraum”
Authors: Lanz Helza Ricarte , Noack Napoles Juliane
Published: September 2015

The aim of this paper is to achieve a better understanding of the impact of bilingualism on children, considering the dimensions of languages, language use and identity. Since 2009, we have been observing German-Brazilian children in an institutional out-of-home-setting in Bonn, Germany, as a case study. Our main question is: “which role does bilingualism play in constructing children’s identities?” The research techniques are participant observation and informal interviews with families. The results show the need of an updated concept that enables us to understand interactions between languages, cultures and societies. This paper represents a work in progress and is submitted as a contribution to the wider ongoing project of developing the concept of “Mehrraum” as an added value space.
Economic phenomena and ideologies behind language shift
Authors: Coluzzi Paolo
Published: September 2015

This article examines the phenomenon of language shift from a macroeconomic and ideological perspective. More specifically it looks at how phenomena such as nationalism and globalization, which are closely related to the capitalist mode of production, have affected the spread of some languages and the demise of others, usually minority and regional languages. A special emphasis is placed on the ideology of modernity as a major cause for language shift in the world. Each section in the article includes examples from the areas in the world where the author has carried out his own research and possible solutions to the problems set forth.
A thiostrepton resistance gene and its mutants serve as selectable markers inGeobacillus kaustophilusHTA426
Authors: Wada Keisuke , Kobayashi Jyumpei , Furukawa Megumi , Doi Katsumi , Ohshiro Takashi , Suzuki Hirokazu
Published: September 2015

Effective utilization of microbes often requires complex genetic modification using multiple antibiotic resistance markers. Because a few markers have been used in Geobacillus spp., the present study was designed to identify a new marker for these thermophiles. We explored antibiotic resistance genes functional in Geobacillus kaustophilus HTA426 and identified a thiostrepton resistance gene (tsr) effective at 50 °C. The tsr gene was further used to generate the mutant tsrH258Y functional at 55 °C. Higher functional temperature of the mutant was attributable to the increase in thermostability of the gene product because recombinant protein produced from tsrH258Y was more thermostable than that from tsr. In fact, the tsrH258Y gene served as a selectable marker for plasmid transformation of G. kaustophilus. This new marker could facilitate complex genetic modification of G. kaustophilus and potentially other Geobacillus spp.
Global analysis of asymmetric RNA enrichment in oocytes reveals low conservation between closely relatedXenopusspecies
Authors: Claußen Maike , Lingner Thomas , Pommerenke Claudia , Opitz Lennart , Salinas Gabriela , Pieler Tomas
Published: September 2015

RNAs that localize to the vegetal cortex during Xenopus laevis oogenesis have been reported to function in germ layer patterning, axis determination, and development of the primordial germ cells. Here we report on the genome-wide, comparative analysis of differentially localizing RNAs in Xenopus laevis and Xenopus tropicalis oocytes, revealing a surprisingly weak degree of conservation in respect to the identity of animally as well as vegetally enriched transcripts in these closely related species. Heterologous RNA injections and protein binding studies indicate that the different RNA localization patterns in these two species are due to gain/loss of cis-acting localization signals rather than to differences in the RNA-localizing machinery.
MDM1 is a microtubule-binding protein that negatively regulates centriole duplication
Authors: Van de Mark Daniel , Kong Dong , Loncarek Jadranka , Stearns Tim
Published: September 2015

Mouse double-minute 1 ( Mdm1) was originally identified as a gene amplified in transformed mouse cells and more recently as being highly up-regulated during differentiation of multiciliated epithelial cells, a specialized cell type having hundreds of centrioles and motile cilia. Here we show that the MDM1 protein localizes to centrioles of dividing cells and differentiating multiciliated cells. 3D-SIM microscopy showed that MDM1 is closely associated with the centriole barrel, likely residing in the centriole lumen. Overexpression of MDM1 suppressed centriole duplication, whereas depletion of MDM1 resulted in an increase in granular material that likely represents early intermediates in centriole formation. We show that MDM1 binds microtubules in vivo and in vitro. We identified a repeat motif in MDM1 that is required for efficient microtubule binding and found that these repeats are also present in CCSAP, another microtubule-binding protein. We propose that MDM1 is a negative regulator of centriole duplication and that its function is mediated through microtubule binding.
A Pan1/End3/Sla1 complex links Arp2/3-mediated actin assembly to sites of clathrin-mediated endocytosis
Authors: Sun Yidi , Leong Nicole T. , Wong Tiffany , Drubin David G.
Published: September 2015

More than 60 highly conserved proteins appear sequentially at sites of clathrin-mediated endocytosis in yeast and mammals. The yeast Eps15-related proteins Pan1 and End3 and the CIN85-related protein Sla1 are known to interact with each other in vitro, and they all appear after endocytic-site initiation but before endocytic actin assembly, which facilitates membrane invagination/scission. Here we used live-cell imaging in parallel with genetics and biochemistry to explore comprehensively the dynamic interactions and functions of Pan1, End3, and Sla1. Our results indicate that Pan1 and End3 associate in a stable manner and appear at endocytic sites before Sla1. The End3 C-terminus is necessary and sufficient for its cortical localization via interaction with Pan1, whereas the End3 N-terminus plays a crucial role in Sla1 recruitment. We systematically examined the dynamic behaviors of endocytic proteins in cells in which Pan1 and End3 were simultaneously eliminated, using the auxin-inducible degron system. The results lead us to propose that endocytic-site initiation and actin assembly are separable processes linked by a Pan1/End3/Sla1 complex. Finally, our study provides mechanistic insights into how Pan1 and End3 function with Sla1 to coordinate cargo capture with actin assembly.
The myth of standardized workflow in primary care
Authors: Holman G Talley , Beasley John W , Karsh Ben-Tzion , Stone Jamie A , Smith Paul D , Wetterneck Tosha B
Published: September 2015

Objective Primary care efficiency and quality are essential for the nation’s health. The demands on primary care physicians (PCPs) are increasing as healthcare becomes more complex. A more complete understanding of PCP workflow variation is needed to guide future healthcare redesigns.

Methods This analysis evaluates workflow variation in terms of the sequence of tasks performed during patient visits. Two patient visits from 10 PCPs from 10 different United States Midwestern primary care clinics were analyzed to determine physician workflow. Tasks and the progressive sequence of those tasks were observed, documented, and coded by task category using a PCP task list. Variations in the sequence and prevalence of tasks at each stage of the primary care visit were assessed considering the physician, the patient, the visit’s progression, and the presence of an electronic health record (EHR) at the clinic.

Results PCP workflow during patient visits varies significantly, even for an individual physician, with no single or even common workflow pattern being present. The prevalence of specific tasks shifts significantly as primary care visits progress to their conclusion but, notably, PCPs collect patient information throughout the visit.

Discussion PCP workflows were unpredictable during face-to-face patient visits. Workflow emerges as the result of a “dance” between physician and patient as their separate agendas are addressed, a side effect of patient-centered practice.

Conclusions Future healthcare redesigns should support a wide variety of task sequences to deliver high-quality primary care. The development of tools such as electronic health records must be based on the realities of primary care visits if they are to successfully support a PCP’s mental and physical work, resulting in effective, safe, and efficient primary care.
A new visual navigation system for exploring biomedical Open Educational Resource (OER) videos
Authors: Zhao Baoquan , Xu Songhua , Lin Shujin , Luo Xiaonan , Duan Lian
Published: September 2015

Objective Biomedical videos as open educational resources (OERs) are increasingly proliferating on the Internet. Unfortunately, seeking personally valuable content from among the vast corpus of quality yet diverse OER videos is nontrivial due to limitations of today’s keyword- and content-based video retrieval techniques. To address this need, this study introduces a novel visual navigation system that facilitates users’ information seeking from biomedical OER videos in mass quantity by interactively offering visual and textual navigational clues that are both semantically revealing and user-friendly.

Materials and Methods The authors collected and processed around 25 000 YouTube videos, which collectively last for a total length of about 4000 h, in the broad field of biomedical sciences for our experiment. For each video, its semantic clues are first extracted automatically through computationally analyzing audio and visual signals, as well as text either accompanying or embedded in the video. These extracted clues are subsequently stored in a metadata database and indexed by a high-performance text search engine. During the online retrieval stage, the system renders video search results as dynamic web pages using a JavaScript library that allows users to interactively and intuitively explore video content both efficiently and effectively.

Results The authors produced a prototype implementation of the proposed system, which is publicly accessible at https://patentq.njit.edu/oer . To examine the overall advantage of the proposed system for exploring biomedical OER videos, the authors further conducted a user study of a modest scale. The study results encouragingly demonstrate the functional effectiveness and user-friendliness of the new system for facilitating information seeking from and content exploration among massive biomedical OER videos.

Conclusion Using the proposed tool, users can efficiently and effectively find videos of interest, precisely locate video segments delivering personally valuable information, as well as intuitively and conveniently preview essential content of a single or a collection of videos.
Local Health Departments Tweeting About Ebola: Characteristics and Messaging
Authors: Wong Roger , Harris Jenine K. , Staub Mackenzie , Bernhardt Jay M.
Published: September 2015

Context:

The first imported US Ebola hemorrhagic fever case during the 2014 West Africa Ebola outbreak triggered an increase in online activity through various social media platforms, including Twitter.

Objectives:

The purpose of our study was to examine characteristics of local health departments (LHDs) tweeting about Ebola, in addition to how and when LHDs were communicating Ebola-related messages.

Design:

All tweets sent by 287 LHDs known to be using Twitter were collected from September 3 to November 2, 2014. Twitter data were merged with the 2013 National Association of County & City Health Officials Profile study to assess LHD characteristics associated with sending Ebola-related tweets. To examine the content of Ebola tweets, we reviewed all such tweets and developed a codebook including 4 major message categories: information giving, news update, event promotion, and preparedness. A time line tracking the trends in Ebola tweets was created by aligning daily tweets with major Ebola news events posted on the Centers for Disease Control and Prevention Ebola Web site.

Results:

Approximately 60% (n = 174) of all LHDs using Twitter sent a total of 1648 Ebola-related tweets during the study period. Sending more tweets in general (odds ratio: 2.42; 95% confidence interval, 1.00-5.84) and employing at least 1 public information specialist (odds ratio: 2.61; 95% confidence interval, 1.14-5.95) significantly increased the odds that an LHD tweeted about Ebola. Of all the Ebola tweets collected, 78.6% were information giving, 22.5% were on preparedness, 20.8% were news updates, and 10.3% were event promotion tweets. A temporal analysis of Ebola tweets indicated 5 distinct waves, each corresponding with major Ebola news events.

Conclusions:

Twitter has become a communication tool frequently used by many LHDs to respond to novel outbreaks, but messaging strategies vary widely across LHDs. We recommend that LHDs increase tweet frequency during public health emergencies in order to ensure timely dissemination of critical information.
Paraglycomyces xinjiangensis gen. nov., sp. nov., a halophilic actinomycete
Authors: Luo Xiao-Xia , Han Xiao-Xue , Zhang Fei , Wan Chuan-Xing , Zhang Li-Li
Published: September 2015

A novel halophilic actinobacterium, designated strain TRM 49201T, was isolated from a hypersaline soil in Xinjiang Province, north-west China. The strain was aerobic, Gram-stain-positive and halophilic. The aerial mycelium was chaotic with irregular branches, and spherical sporangia containing several spherical spores developed at mycelial aggregations. The strain had an optimum NaCl concentration for growth of 8–13 % (w/v). The whole-cell sugar pattern of strain TRM 49201T consisted of xylose and ribose. The predominant menaquinones were MK-9(H4), MK-9(H6) and MK-10(H2). The polar lipids were diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylinositol, phosphatidylglycerol, phosphatidylcholine and four unknown phospholipids. The major fatty acids were anteiso-C15 : 0, iso-C16 : 0 and anteiso-C17 : 0. The G+C content of the genomic DNA was 70 mol%. Phylogenetic analysis showed that strain TRM 49201T can be distinguished from representatives of Glycomyces, Stackebrandtia and Haloglycomyces, the three existing genera in the family Glycomycetaceae, based on low 16S rRNA gene sequence similarities ( < 94.42 %). Strain TRM 49201T is thus considered to represent a novel species of a new genus in the family Glycomycetaceae, for which the name Paraglycomyces xinjiangensis gen. nov., sp. nov. is proposed. The type strain of Paraglycomyces xinjiangensis is TRM 49201T ( = NRRL B-24926T = CCTCC AA 2013002T = KACC 17683T).
How many dinosaur species were there? Fossil bias and true richness estimated using a Poisson sampling model (TRiPS)
Authors: Starrfelt Jostein , Liow Lee Hsiang
Published: September 2015

The fossil record is a rich source of information about biological diversity in the past. However, the fossil record is not only incomplete but has inherent biases due to geological, physical, chemical and biological factors. Our knowledge of past life is also biased because of differences in academic and amateur interests and sampling efforts. As a result, not all individuals or species that lived in the past are equally likely to be discovered at any point in time or space. To reconstruct temporal dynamics of diversity using the fossil record, biased sampling must be explicitly taken into account. Here, we introduce an approach that utilizes the variation in the number of times each species is observed in the fossil record to estimate both sampling bias and true richness. We term our technique TRiPS (True Richness estimated using a Poisson Sampling model) and explore its robustness to violation of its assumptions via simulations. We then venture to estimate sampling bias and absolute species richness of dinosaurs in the geological stages of the Mesozoic. Using TRiPS, we estimate that 1936 (1543-2468) species of dinosaurs roamed the Earth during the Mesozoic. We also present improved estimates of species richness trajectories of the three major dinosaur clades; the sauropodomorphs, ornithischians and theropods, casting doubt on the Jurassic-Cretaceous extinction event and demonstrating that all dinosaur groups are subject to considerable sampling bias throughout the Mesozoic.
Comparing RADseq and microsatellites to infer complex phylogeographic patterns, a real data informed perspective in the Crucian carp,Carassius carassius, L
Authors: Jeffries Daniel L , Copp Gordon H , Handley Lori Lawson , Håkan Olsén K. , Sayer Carl D , Hänfling Bernd
Published: September 2015

The conservation of threatened species must be underpinned by phylogeographic knowledge in order to be effective. This need is epitomised by the freshwater fishCarassius carassius, which has recently undergone drastic declines across much of its European range. Restriction Site Associated DNA sequencing (RADseq) is being increasingly used for such phylogeographic questions, however RADseq is expensive, and limitations on sample number must be weighed against the benefit of large numbers of markers. Such tradeoffs have predominantly been addressed using simulated data. Here we compare the results generated from microsatellites and RADseq to the phylogeography ofC. carassius, to add real-data-informed perspectives to this important debate. These datasets, along with data from the mitochondrial cytochrome b gene, agree on broad phylogeographic patterns; showing the existence of two previously unidentifiedC. carassiuslineages in Europe. These lineages have been isolated for approximately 2.2-2.3 M years, and should arguably be considered as separate conservation units. RADseq recovered finer population structure and stronger patterns of IBD than microsatellites, despite including only 17.6% of samples (38% of populations and 52% of samples per population). RADseq was also used along with Approximate Bayesian Computation to show that the postglacial colonisation routes ofC. carassiusdiffer from the general patterns of freshwater fish in Europe, likely as a result of their distinctive ecology.
Application of a dense genetic map for assessment of genomic responses to selection and inbreeding in Heliothis virescens.
Authors: Fritz Megan , Paa Sandra , Baltzegar Jennifer , Gould Fred
Published: September 2015

Adaptation of pest species to laboratory conditions and selection for resistance to toxins in the laboratory are expected to cause inbreeding and genetic bottlenecks that reduce genetic variation. Heliothis virescens, a major cotton pest, has been colonized in the laboratory many times, and a few laboratory colonies have been selected for Bt resistance. We developed 350 bp Double-Digest Restriction-site Associated DNA-sequencing (ddRAD-seq) molecular markers to examine and compare changes in genetic variation associated with laboratory adaptation, artificial selection, and inbreeding in this non-model insect species. We found that allelic and nucleotide diversity declined dramatically in laboratory-reared H. virescens as compared with field-collected populations. The declines were primarily due to the loss of low frequency alleles present in field-collected H. virescens. A further, albeit modest decline in genetic diversity was observed in a Bt-selected population. The greatest decline was seen in H. virescens that were sib-mated for 10 generations, where more than 80% of loci were fixed for a single allele. To determine which regions of the genome were resistant to fixation in our sib-mated line, we generated a dense intraspecific linkage map containing 3 PCR-based, and 659 ddRAD-seq markers. Markers that retained polymorphism were observed in small clusters spread over multiple linkage groups, but this clustering was not statistically significant. Here, we confirmed and extended the general expectations for reduced genetic diversity in laboratory colonies, provided tools for further genomic analyses, and produced highly homozygous genomic DNA for future whole genome sequencing of H. virescens.