bluuebunny/crossref_metadata_2025 huggingface dataset:
Separation of platelets from other blood cells in continuous-flow by dielectrophoresis field-flow-fractionation
Authors: Piacentini Niccolò , Mernier Guillaume , Tornay Raphaël , Renaud Philippe
Published: September 2011

We present a microfluidic device capable of separating platelets from other blood cells in continuous flow using dielectrophoresis field-flow-fractionation. The use of hydrodynamic focusing in combination with the application of a dielectrophoretic force allows the separation of platelets from red blood cells due to their size difference. The theoretical cell trajectory has been calculated by numerical simulations of the electrical field and flow speed, and is in agreement with the experimental results. The proposed device uses the so-called “liquid electrodes” design and can be used with low applied voltages, as low as 10 Vpp. The obtained separation is very efficient, the device being able to achieve a very high purity of platelets of 98.8% with less than 2% cell loss. Its low-voltage operation makes it particularly suitable for point-of-care applications. It could further be used for the separation of other cell types based on their size difference, as well as in combination with other sorting techniques to separate multiple cell populations from each other.
Heat transfer simulation and thermal measurements of microfabricated x-ray transparent heater stages
Authors: Baldasseroni C. , Queen D. R. , Cooke David W. , Maize K. , Shakouri A. , Hellman F.
Published: September 2011

A microfabricated amorphous silicon nitride membrane-based nanocalorimeter is proposed to be suitable for an x-ray transparent sample platform with low power heating and built-in temperature sensing. In this work, thermal characterization in both air and vacuum are analyzed experimentally and via simulation. Infrared microscopy and thermoreflectance microscopy are used for thermal imaging of the sample area in air. While a reasonably large isothermal area is found on the sample area, the temperature homogeneity of the entire sample area is low, limiting use of the device as a heater stage in air or other gases. A simulation model that includes conduction, as well as radiation and convection heat loss, is presented with radiation and convection parameters determined experimentally. Simulated temperature distributions show that the homogeneity can be improved by using a thicker thermal conduction layer or reducing the pressure of the gas in the environment but neither are good solutions for the proposed use. A new simple design that has improved temperature homogeneity and a larger isothermal area while maintaining a thin thermal conduction layer is proposed and fabricated. This new design enables applications in transmission x-ray microscopes and spectroscopy setups at atmospheric pressure.
Self-assembly on (111)-oriented III-V surfaces
Authors: Simmonds Paul J. , Larry Lee Minjoo
Published: September 2011

We demonstrate the self-assembly of tensile strained GaP into three-dimensional dots on GaAs(111)A. Size and areal density of the dislocation-free GaP dots are readily tunable with both substrate temperature and deposition thickness. GaP dot growth obeys island scaling theory, allowing us to predict dot size distributions a priori.
Quasi-optical theory of relativistic submillimeter surface-wave oscillators
Authors: Ginzburg N. S. , Malkin A. M. , Sergeev A. S. , Zaslavsky V. Yu.
Published: September 2011

Within the framework of a quasi-optical approach, the nonlinear theory of relativistic surface-wave oscillators is developed. By presenting the radiation field as a sum of two counter-propagating wave-beams which are coupled on a shallow corrugated surface, we describe formation of an evanescent slow wave. Taking into account the excitation of a slow wave by a sheet electron beam, we simulate linear and nonlinear stages of interaction that allows us to define the threshold conditions, the electron efficiency, and the output coupling. It is shown that the considered type of an oscillator can be used for generation of powerful sub-THz radiation.
Microwave breakdown of low pressure N2 gas in microgaps
Authors: Klein T. J. , Ploch Christopher J. , Recknagel Cameron J. , Remillard S. K.
Published: September 2011

The pressure dependence of the breakdown of nitrogen gas by a microwave field in microgaps down to 13 μm has been measured. Fits to a phenomenological function suggest that microwave breakdown in small gaps requires a higher collision frequency, νc. If the effective electric field on an electron in a microgap is interpreted as Eeff=Eoνc2/(νc2+ω2) and then as the gap size is reduced, we find that the collision frequency needed to produce a minimum breakdown electric field shifts from νc = ω for large gaps to νc = 2ω for small gaps.
Energy-storage performance and electrocaloric effect in (100)-oriented Pb0.97La0.02(Zr0.95Ti0.05)O3 antiferroelectric thick films
Authors: Hao Xihong , Yue Zhenxing , Xu Jinbao , An Shengli , Nan Ce-Wen
Published: September 2011

(100)-oriented Pb0.97La0.02(Zr0.95Ti0.05)O3 (PLZT) antiferroelectric films with a thickness of about 1.7 μm were deposited on Pt-buffered silicon substrates via a sol-gel process. The room-temperature capacitance density of the films was above 195 nF/cm2 over the frequency range from 1 kHz to 1 MHz. The recoverable energy density was enlarged with increasing measurement field, and a maximum value of 12.4 J/cm3 at 1120 kV/cm was obtained at room temperature. From the temperature-dependent electric-field-induced polarization hysteresis loops, a maximum reversible adiabatic temperature change, ΔT = 8.5 °C, was obtained near the phase-transition temperature.
The quasi-free-standing nature of graphene on H-saturated SiC(0001)
Authors: Speck F. , Jobst J. , Fromm F. , Ostler M. , Waldmann D. , Hundhausen M. , Weber H. B. , Seyller Th.
Published: September 2011

We report on an investigation of quasi-free-standing graphene on 6H-SiC(0001) which was prepared by intercalation of hydrogen under the buffer layer. Using infrared absorption spectroscopy, we prove that the SiC(0001) surface is saturated with hydrogen. Raman spectra demonstrate the conversion of the buffer layer into graphene which exhibits a slight tensile strain and short range defects. The layers are hole doped (p = 5.0 − 6.5 × 1012 cm−2) with a carrier mobility of 3100 cm2/Vs at room temperature. Compared to graphene on the buffer layer, a strongly reduced temperature dependence of the mobility is observed for graphene on H-terminated SiC(0001) which justifies the term “quasi-free-standing.”
Self-assembly of metallic nanoparticles into plasmonic rings
Authors: Lerond Thomas , Proust Julien , Yockell-Lelièvre Hélène , Gérard Davy , Plain Jérôme
Published: September 2011

Metallic nanoparticles are self-assembled into plasmonic nanorings. The self-assembly is evaporation-induced and is driven using a template of dielectric microspheres. We obtain well-ordered arrays of metallic nanorings over large areas. The inner and outer diameters of the rings, as well as the pitch of the array, are fully controllable. The optical resonances supported by the plasmonic rings are then characterized using extinction spectroscopy. Our approach opens a simple and inexpensive road to create plasmonic structures that can find applications as metamaterials or substrates for enhanced spectroscopies.
Evaluating AlGaN/AlN/GaN heterostructure Schottky barrier heights with flat-band voltage from forward current-voltage characteristics
Authors: Lv Yuanjie , Lin Zhaojun , Meng Lingguo , Yu Yingxia , Luan Chongbiao , Cao Zhifang , Chen Hong , Sun Baoquan , Wang Zhanguo
Published: September 2011

Both circular and rectangular Ni Schottky contacts on AlGaN/AlN/GaN heterostructures have been fabricated. Both of the Schottky barrier heights were measured by internal photoemission. The flat-band voltage (V0) for the AlGaN/AlN/GaN heterostructure Schottky contacts was analyzed and obtained from the forward current-voltage (I-V) characteristics. Based on the forward I-V characteristics and with the obtained flat-band voltage, the Schottky barrier heights for the circular and rectangular diodes have been analyzed and calculated by self-consistently solving Schrodinger’s and Poisson’s equations. The evaluated Schottky barrier heights for the prepared circular and rectangular Ni Schottky diodes agree well with the photocurrent measured results.
Coherent quantum cascade laser micro-stripe arrays
Authors: de Naurois G. M. , Carras M. , Simozrag B. , Patard O. , Alexandre F. , Marcadet X.
Published: September 2011

We have fabricated InP-based coherent quantum cascade laser micro-stripe arrays. Phase-locking is provided by evanescent coupling between adjacent stripes. Stripes are buried into semi-insulating iron doped InP. Lasing at room temperature is obtained at 8.4μm for stripe arrays comprising up to 16 emitters. Pure supermode emission is demonstrated via farfield measurements and simulations. The farfield pattern shows a dual-lobe emission, corroborating the predicted phase-locked antisymmetric supermode emission.
Indirect absorption in germanium quantum wells
Authors: Schaevitz R. K. , Ly-Gagnon D. S. , Roth J. E. , Edwards E. H. , Miller D. A. B.
Published: September 2011

Germanium has become a promising material for creating CMOS-compatible optoelectronic devices, such as modulators and detectors employing the Franz-Keldysh effect (FKE) or the quantum-confined Stark effect (QCSE), which meet strict energy and density requirements for future interconnects. To improve Ge-based modulator design, it is important to understand the contributions to the insertion loss (IL). With indirect absorption being the primary component of IL, we have experimentally determined the strength of this loss and compared it with theoretical models. For the first time, we have used the more sensitive photocurrent measurements for determining the effective absorption coefficient in our Ge/SiGe quantum well material employing QCSE. This measurement technique enables measurement of the absorption coefficient over four orders of magnitude. We find good agreement between our thin Ge quantum wells and the bulk material parameters and theoretical models. Similar to bulk Ge, we find that the 27.7 meV LA phonon is dominant in these quantum confined structures and that the electroabsorption profile can be predicted using the model presented by Frova, Phys. Rev., 145 (1966).
Tuning the conductivity of vanadium dioxide films on silicon by swift heavy ion irradiation
Authors: Hofsäss H. , Ehrhardt P. , Gehrke H.-G. , Brötzmann M. , Vetter U. , Zhang K. , Krauser J. , Trautmann C. , Ko C. , Ramanathan S.
Published: September 2011

We demonstrate the generation of a persistent conductivity increase in vanadium dioxide thin films grown on single crystal silicon by irradiation with 1 GeV 238U swift heavy ions at room temperature. VO2 undergoes a temperature driven metal-insulator-transition (MIT) at 67 °C. After room temperature ion irradiation with high electronic energy loss of 50 keV/nm the conductivity of the films below the transition temperature is strongly increased proportional to the ion fluence of 5·109 U/cm2 and 1·1010 U/cm2. At high temperatures the conductivity decreases slightly. The ion irradiation slightly reduces the MIT temperature. This observed conductivity change is persistent and remains after heating the samples above the transition temperature and subsequent cooling. Low temperature measurements down to 15 K show no further MIT below room temperature. Although the conductivity increase after irradiation at such low fluences is due to single ion track effects, atomic force microscopy (AFM) measurements do not show surface hillocks, which are characteristic for ion tracks in other materials. Conductive AFM gives no evidence for conducting ion tracks but rather suggests the existence of conducting regions around poorly conducting ion tracks, possible due to stress generation. Another explanation of the persistent conductivity change could be the ion-induced modification of a high resistivity interface layer formed during film growth between the vanadium dioxide film and the n-Silicon substrate. The swift heavy ions may generate conducting filaments through this layer, thus increasing the effective contact area. Swift heavy ion irradiation can thus be used to tune the conductivity of VO2 films on silicon substrates.
Disruption of insect diapause using agonists and an antagonist of diapause hormone
Authors: Zhang Qirui , Nachman Ronald J. , Kaczmarek Krzysztof , Zabrocki Janusz , Denlinger David L.
Published: September 2011

The dormant state known as diapause is widely exploited by insects to circumvent winter and other adverse seasons. For an insect to survive, feed, and reproduce at the appropriate time of year requires fine coordination of the timing of entry into and exit from diapause. One of the hormones that regulates diapause in moths is the 24-aa neuropeptide, diapause hormone (DH). Among members of the
Helicoverpa
/
Heliothis
complex of agricultural pests, DH prompts the termination of pupal diapause. Based on the structure of DH, we designed several agonists that are much more active than DH in breaking diapause. One such agonist that we describe also prevents the entry into pupal diapause when administered to larvae that are environmentally programmed for diapause. In addition, we used the unique antagonist development strategy of incorporating a dihydroimidazole (“Jones”)
trans
-Proline mimetic motif into one of our DH agonists, thereby converting the agonist into a DH antagonist that blocks the termination of diapause. These results suggest potential for using such agents or next-generation derivatives for derailing the success of overwintering in pest species.
How Political are the Social Movements in the Baltic Republics?
Authors: Shtromas Alexandras
Published: September 2011

Before the 1980s one hardly spoke of any significant social movements in the Baltic republics. Political apathy, bordering on hopelessness, as far as the masses were concerned, and an emphasized apoliticism of the intelligentsia, whose members never tired of stressing that their only concerns are professional, cultural, maybe aesthetic, but not at all political—that was the social situation in the Baltic states most of the time under Soviet rule.

This overall image of apathy, complacency, and acquiescence was, however, not entirely correct. Underneath there were many things happening, as very few Balts indeed were total conformists and total loyalists of the Soviet regime. Most of them were, rather, “conservationists.” That is a special term I use for people outwardly loyal to the Soviet system, working within that system, trying to comply with the rules of the system, but at the same time using whatever position in the system they have to preserve their nation's economic, cultural, and historical heritage. They were trying especially hard to safeguard their nation's economic well-being, ecological situation and, of course, spiritual identity and heritage, by promoting art, literature and other activities, mainly under the slogan “national in form and socialist in content,” but more and more national in form and less and less socialist in content, as far as the circumstances allowed it. These people wore the disguise of Soviet loyalism for the benefit and the advantage of their own nation; that was the attitude I call conservationism in the Baltic states and that was the attitude that was prevalent among most native Balts.
Editorial Note: “Mission Accomplished? Or a New Agenda?”
Authors: H. R. H.
Published: September 2011

In 1989, with the start of this series—so many momentous events ago—there existed a Soviet Union and, within it, there had been Soviet republics (all socialist!). The entirety was imperially presided over by Mikhail Sergeyevich Gorbachev, Chairman of the Communist Party and President of the USSR.
The Annexation of Tannu-Tuva and the Formation of the Tuvinskaya ASSR
Authors: Mongush Mergen
Published: September 2011

Although the Tuvinskaya ASSR is one of the latest and, in fact, the largest of the territorial acquisitions of the Soviet Union (its area exceeds that of all three Baltic states at 170,500 sq. kilometers), there are few, if any, detailed accounts of its annexation in 1944.
VI. “Contemporary Relations Among Nationalities in Ukraine”
Authors: Sazhin Valentin
Published: September 2011

A recent investigation of attitudes among nationalities living in Ukraine reveals a low level of tolerance and high level of hostility towards the non-Slavic nationalities. This was the foremost conclusion of Dr. Valentin Sazhin, who surveyed 10,000 residents of Ukraine on matters relating to ethnicity. Dr. Sazhin based his presentation on the findings from this investigation.
Beyond common sense: reconceptualizing National Curriculum assessment
Authors: RUTHVEN KENNETH
Published: September 2011

This article examines the implications of the shift, in England and Wales, from the pre‐Dearing National Curriculum assessment model based on the assessment of performance in relation to statements of attainment, to the post‐Dearing model based on level descriptions. Both the original and r..vised models reflect a common sense view that learning is marked by stepwise acquisition of curricular objectives, with assessment providing robust and interpretable indices of such progress. However, two key shifts in conceptualization have taken place: from a focus on actual performance on individual objectives to idealized performance on complexes of objectives; and from a concept of hierarchical progression to one of cumulative progression. The article highlights some of the central weaknesses of the common sense view, in both its original and revised versions, by reference to the findings of research on assessment in mathematics. Neither model takes sufficient account of the extent to which development and learning in mathematics involve progressive, but uneven, consolidation, co‐ordination and reorganization of knowledge, with stability of performance achieved only at the end of this process. A more fruitful, but controversial, way forward would be to conceptualize a pupil's learning as taking place in a development band, in which concepts are still being refined. This would recognize that performance is less consistent in this band, and that task content and presentation have an important influence. The creation of such a system would demand the improved definition of attainment targets, and scaling within them, through further research; and the development of teacher assessment and standard assessment so that they can be genuinely complementary. Reliance on politically expedient short tests is unlikely to prove either trustworthy or informative.
The changing role of the primary school curriculum co‐ordinator
Authors: WEBB ROSEMARY , VULLIAMY GRAHAM
Published: September 2011

The paper examines the changing role of primary school curriculum co‐ordinators following the implementation of the 1988 Education Reform Act and in the context of recent government and OFSTED exhortations for better subject teaching. Based upon qualitative data from a national sample of 50 schools in England and Wales, it argues that several factors have recently raised the status and influence of curriculum co‐ordinators in schools. They were playing a major role in whole‐school curriculum planning and policy‐making and were raising the collective confidence of staff in their subjects. However, co‐ordinators’ abilities to modify other teachers’ pedagogies were limited by their colleagues’ lack of subject knowledge. In addition, if co‐ordinators are to meet the new demands of their role and have more influence as change agents, they need courses and in‐school support to develop a range of skills, including people management, evaluation techniques and the provision of INSET. Co‐ordinators in some of the sample schools were involved in area networks for specific subjects; they met on a regular basis, rotating around each other's schools, to share initiatives and concerns. In only a few schools was supporting teachers in their classrooms a regular planned and timetabled activity. Lack of non‐contact time militated against such collaborative activities. So also did inter‐personal factors, such as differences in status and authority and feelings of insecurity on behalf of the co‐ordinator, and aspects of the traditional culture of primary schools, which respects class teacher individuality, privacy and autonomy. The paper argues that, because the introduction of the National Curriculum has greatly increased the planning, classroom preparation and assessment responsibilities of class teachers and brought an extended role to curriculum co‐ordinators, the funding disparities between primary and secondary school staffing are no longer justifiable.
Twenty years of history through drama
Authors: GOALEN PAUL
Published: September 2011

In 1974, John Fines and Ray Verrier published The Drama of History which became a source of pedagogical inspiration for history teachers in the UK. This article begins by reviewing the influence of history through drama both as an approach to teaching and learning in classrooms and within the ‘Living History’ movement, which seeks to bring history alive on sites of historic interest. However, like Fines and Verrier, the author's principal interest is in work focused in the classroom which seeks to teach history by drawing on drama strategies wedded to active learning techniques. On the face of it, the introduction of a National Curriculum for history posed a serious threat to the continuation of such pedagogical practices; an overcrowded programme of study, increased emphasis on the acquisition of historical knowledge and pressure from the Right predicted a return to traditional teaching methods. Diminished local support arising from the partial collapse of local education authority structures also betokened the demise of history through drama. The evidence, however, suggests that although teaching style was constrained for a short time while teachers were coming to terms with the National Curriculum, they have held on to their commitment to a mode of pedagogic operation that they value highly. The data on which this observation is based were collected by interview from heads of history in ten state comprehensive schools in 1994. These demonstrated the extent to which history through drama is again being practised in their schools and justified its use in terms of a number of social and educational objectives. This indicates that history teachers have shown a willingness to mediate and interpret the new curriculum rather than be enslaved by it.
Girls, learning and science in the framework of the National Curriculum
Authors: BENTLEY DI , DROBINSKI SAMANTHA
Published: September 2011

This article examines changes in girls’ attitudes towards aspects of science in the context of the National Curriculum. It is based on some research that was conducted by questionnaire with a sample of 420 girls in Y9 who had experienced a common problem‐solving approach to science through participation in the CREST (Creativity in Science and Technology) project. The questionnaires were administered during a major two‐day event organized by the project. This article focuses on the responses to questions concerned with girls’ liking for science generally, their liking for problem‐solving, and their liking for different aspects of science. Responses indicated that liking for science was significantly above the average for liking of other subjects, also that problem‐solving had appeal for its associations with autonomy and control over work, ideas, plans and methods. These results might, however, have been skewed by the context in which the questionnaire was administered. More difficult to account for in terms of contextual influence was that girls reported liking ‘energy’ as an aspect of science. Compared with APU findings, reported in 1989, this suggested a possible shift in preferences away from those which are stereotypical. In an attempt to account for this apparent shift, the authors speculate that the National Curriculum is the only common factor that could have brought about this change, specifically in relation to the concept of energy. Thus the National Curriculum, together with experiences like those provided by CREST, could be changing girls’ attitudes to science.
Rural students’ transitions to secondary school: culture, curriculum and context
Authors: WALSH MARY ELLEN
Published: September 2011

This article is based on a year‐long study of elementary to secondary transition in rural Ontario, Canada. The study considered the experience of transition for rural students within the political context of recently mandated changes to the transition years in Ontario. Research elsewhere suggests that the strong academic orientation of the secondary school creates a polarized and fragmented school culture which leads to student alienation and high drop‐out rates. These issues were regarded as less relevant in the rural area where the study took place and, thus, the teachers, parents and students who participated were sceptical about the need for change. The article examines the influence of contextual factors, including the rural setting, school structure and size, and teacher experience, on school culture and curriculum, and participants’ experiences of transition and their perspectives on change. A dialogical approach to enquiry was taken which attempted to bring together, through dialogue, the disparate views of research and participants to achieve new understandings on the critical issues of rural transition.
Change in education and the mathematics teacher's role in Poland
Authors: Wojciechowska Agnieszka
Published: September 2011

This paper explores the revolutionary and counter‐revolutionary influences that are impacting on Polish schools and Polish planning for the curriculum. The paper looks, in particular, at the issue of school textbooks, the changing focus of state control and the impending impact of computer technology in transforming the politics of control.
The Referendum and the Transformation of the Party System
Authors: Donovan Mark
Published: September 2011

Wholesale party system transformation is exceedingly rare. Indeed, in taking place within a broadly democratic framework and independently of constitutional change Italy's experience is probably unique. This paper argues that the referendums of 1991 and 1993, and the mobilization of the electorate from early 1990 associated with them, played a significant and not always well understood role in the transformation of the Italian party system.
2D ECE measurements of type-I edge localized modes at ASDEX Upgrade
Authors: Boom J.E. , Classen I.G.J. , de Vries P.C. , Eich T. , Wolfrum E. , Suttrop W. , Wenninger R.P. , Donné A.J.H. , Tobias B.J. , Domier C.W. , Luhmann N.C. , Park H.K.
Published: September 2011

The installation of a 2D electron cyclotron emission imaging (ECEI) diagnostic on ASDEX Upgrade has provided a new means to observe the nature of edge localized modes (ELMs). For a series of ELMs in a typical type-I ELMy H-mode (with q
95 = 4.7), the 2D dynamics have been characterized. Firstly, a clear distinction between so-called ‘fast’ and ‘slow’ ELMs was found to be the occurrence of an off-mid-plane fluctuation in case of the latter. This mode has its amplitude strongest off-mid-plane and its poloidal and toroidal mode numbers are m ∼ 110 and n ∼ 30. Secondly, prior to the onset of the ELM's temperature collapse, a mode is observed that covers the whole ECEI-observation window. Here, the estimated poloidal and toroidal mode numbers are m ∼ 75 and n ∼ 20. These have been seen to increase towards the ELM crash, simultaneously with a velocity increase of the mode (in poloidal direction). Finally, filaments have been identified during the temperature collapse phase and their motion could be followed in the vertical direction. In contrast to both the off-mid-plane fluctuation and the ELM-onset mode, which only have been seen rotating in the electron diamagnetic drift direction, the first few filaments have sometimes been observed to move in the opposite direction as well.
Nonlinear ELM simulations based on a nonideal peeling–ballooning model using the BOUT++ code
Authors: Xu X.Q. , Dudson B.D. , Snyder P.B. , Umansky M.V. , Wilson H.R. , Casper T.
Published: September 2011

A minimum set of equations based on the peeling–ballooning (P–B) model with nonideal physics effects (diamagnetic drift, E × B drift, resistivity and anomalous electron viscosity) is found to simulate pedestal collapse when using the BOUT++ simulation code, developed in part from the original fluid edge code BOUT. Linear simulations of P–B modes find good agreement in growth rate and mode structure with ELITE calculations. The influence of the E × B drift, diamagnetic drift, resistivity, anomalous electron viscosity, ion viscosity and parallel thermal diffusivity on P–B modes is being studied; we find that (1) the diamagnetic drift and E × B drift stabilize the P–B mode in a manner consistent with theoretical expectations; (2) resistivity destabilizes the P–B mode, leading to resistive P–B mode; (3) anomalous electron and parallel ion viscosities destabilize the P–B mode, leading to a viscous P–B mode; (4) perpendicular ion viscosity and parallel thermal diffusivity stabilize the P–B mode. With addition of the anomalous electron viscosity under the assumption that the anomalous kinematic electron viscosity is comparable to the anomalous electron perpendicular thermal diffusivity, or the Prandtl number is close to unity, it is found from nonlinear simulations using a realistic high Lundquist number that the pedestal collapse is limited to the edge region and the ELM size is about 5–10% of the pedestal stored energy. This is consistent with many observations of large ELMs. The estimated island size is consistent with the size of fast pedestal pressure collapse. In the stable α-zones of ideal P–B modes, nonlinear simulations of viscous ballooning modes or current-diffusive ballooning mode (CDBM) for ITER H-mode scenarios are presented.
Analyses of substantially different plasma current densities and safety factors reconstructed from magnetic diagnostics data
Authors: Zaitsev F.S. , Kostomarov D.P. , Suchkov E.P. , Drozdov V.V. , Solano E.R. , Murari A. , Matejcik S. , Hawkes N.C.
Published: September 2011

The problem of plasma current density and safety factor reconstruction using magnetic field measurements is considered. In the traditional formulation, the problem is strongly ill-posed. In particular, substantially different current densities and safety factors can be equally well attributed to the same set of measurements, given their experimental errors. In other words, the problem can be strongly unstable with respect to the input data. Different constraints are used in practice to make the problem more stable. This paper presents an accurate mathematical formulation of the inverse problem and its variants. A numerical algorithm is provided, which permits us to study the stability with respect to variations in the input data, to find all substantially different solutions, or to prove their absence, and to determine the confidence intervals of the reconstructions. The proposed method also allows establishing the maximum error for a given diagnostic (additional constraint), below which the diagnostic efficiently extracts one solution among several substantially different ones. Examples of very different current density and safety factor reconstructions for measurements with finite accuracy are presented for the original formulation of the inverse problem. Cases of MAST, JET and ITER-like plasmas are considered. It is shown that including the motional Stark effect (MSE) measurements as a constraint, provided the accuracy of MSE measurements is sufficient, allows identifying one solution among several very different ones, obtained without such a constraint. The maximum MSE diagnostics error for efficient identification of this solution is estimated for JET. The approach of this paper can be used for a wide range of ill-posed problems in physics and can help in selecting additional conditions, which can identify the most likely solution among several.
The dynamics of the formation of the edge particle transport barrier at TJ-II
Authors: van Milligen B.Ph. , Pedrosa M.A. , Hidalgo C. , Carreras B.A. , Estrada T. , Alonso J.A. , de Pablos J.L. , Melnikov A. , Krupnik L. , Eliseev L.G. , Perfilov S.V.
Published: September 2011

A large set of discharges with both spontaneous and forced confinement transitions at low electron density is studied at the stellarator TJ-II in different magnetic configurations. By means of a Bayesian technique, using reflectometry and interferometry, electron density profiles are reconstructed in the outer half of the plasma. A scanning heavy ion beam probe delivers information on the global evolution of the plasma potential. Langmuir probes are used to measure long-range correlations. Together, a comprehensive picture is obtained of the evolution of various key global plasma profiles and parameters across forward and backward transitions associated with the formation of an edge sheared flow layer. The impact of low-order rationals on the transition is elucidated.
The phosphotransferase VanU represses expression of four qrr genes antagonizing VanO-mediated quorum-sensing regulation in Vibrio anguillarum
Authors: Weber Barbara , Lindell Kristoffer , El Qaidi Samir , Hjerde Erik , Willassen Nils-Peder , Milton Debra L.
Published: September 2011

Vibrio anguillarumutilizes quorum sensing to regulate stress responses required for survival in the aquatic environment. Like otherVibriospecies,V. anguillarumcontains the geneqrr1, which encodes the ancestral quorum regulatory RNA Qrr1, and phosphorelay quorum-sensing systems that modulate the expression of small regulatory RNAs (sRNAs) that destabilize mRNA encoding the transcriptional regulator VanT. In this study, three additional Qrr sRNAs were identified. All four sRNAs were positively regulated by σ54and the σ54-dependent response regulator VanO, and showed a redundant activity. The Qrr sRNAs, together with the RNA chaperone Hfq, destabilizedvanTmRNA and modulated expression of VanT-regulated genes. Unexpectedly, expression of all fourqrrgenes peaked at high cell density, and exogenously addedN-acylhomoserine lactone molecules induced expression of theqrrgenes at low cell density. The phosphotransferase VanU, which phosphorylates and activates VanO, repressed expression of the Qrr sRNAs and stabilizedvanTmRNA. A model is presented proposing that VanU acts as a branch point, aiding cross-regulation between two independent phosphorelay systems that activate or repress expression of the Qrr sRNAs, giving flexibility and precision in modulating VanT expression and inducing a quorum-sensing response to stresses found in a constantly changing aquatic environment.
Natural transformation with synthetic gene cassettes: new tools for integron research and biotechnology
Authors: Gestal Alicia M. , Liew Elissa F. , Coleman Nicholas V.
Published: September 2011

Integrons are genetic elements that can capture and express genes packaged as gene cassettes. Here we report new methods that allow integrons to be studied and manipulated in their native bacterial hosts. Synthetic gene cassettes encoding gentamicin resistance (aadB) and green fluorescence (gfp), or lactose metabolism (lacZY), were made by PCR and self-ligation, converted to large tandem arrays by multiple displacement amplification, and introduced intoEscherichia coliorPseudomonas stutzeristrains via electroporation or natural transformation. Recombinants (GmRor Lac+) were obtained at frequencies ranging from 101to 106c.f.u. (µg DNA)−1. Cassettes were integrated by site-specific recombination at the integronattIsite in nearly all cases examined (370/384), including both promoterless and promoter-containing cassettes. Fluorometric analysis ofgfp-containing recombinants revealed that expression levels from the integron-associated promoter PCwere five- to 10-fold higher in the plasmid-borne integron In3compared with theP. stutzerichromosomal integrons. Integration oflacZYcassettes intoP. stutzeriintegrons allowed the bacteria to grow on lactose, and thelacZYgene cassette was stably maintained in the absence of selection. This study is believed to be the first to show natural transformation by gene cassettes, and integron-mediated capture of catabolic gene cassettes.
Comparative methylomics reveals gene-body H3K36me3 in Drosophila predicts DNA methylation and CpG landscapes in other invertebrates
Authors: Nanty Lisa , Carbajosa Guillermo , Heap Graham A. , Ratnieks Francis , van Heel David A. , Down Thomas A. , Rakyan Vardhman K.
Published: September 2011

In invertebrates that harbor functional DNA methylation enzymatic machinery, gene-bodies are the primary targets for CpG methylation. However, virtually all other aspects of invertebrate DNA methylation have remained a mystery until now. Here, using a comparative methylomics approach, we demonstrate that Nematostella vectensis, Ciona intestinalis, Apis mellifera, and Bombyx mori show two distinct populations of genes differentiated by gene-body CpG density. Genome-scale DNA methylation profiles for A. mellifera spermatozoa reveal CpG-poor genes are methylated in the germline, as predicted by the depletion of CpGs. We find an evolutionarily conserved distinction between CpG-poor and GpC-rich genes: The former are associated with basic biological processes, the latter with more specialized functions. This distinction is strikingly similar to that recently observed between euchromatin-associated genes in Drosophila that contain intragenic histone 3 lysine 36 trimethylation (H3K36me3) and those that do not, even though Drosophila does not display CpG density bimodality or methylation. We confirm that a significant number of CpG-poor genes in N. vectensis, C. intestinalis, A. mellifera, and B. mori are orthologs of H3K36me3-rich genes in Drosophila. We propose that over evolutionary time, gene-body H3K36me3 has influenced gene-body DNA methylation levels and, consequently, the gene-body CpG density bimodality characteristic of invertebrates that harbor CpG methylation.
The Tomato MADS-Box Transcription Factor RIPENING INHIBITOR Interacts with Promoters Involved in Numerous Ripening Processes in a COLORLESS NONRIPENING-Dependent Manner
Authors: Martel Catherine , Vrebalov Julia , Tafelmeyer Petra , Giovannoni James J.
Published: September 2011

Fruit ripening is a complex developmental process responsible for the transformation of the seed-containing organ into a tissue attractive to seed dispersers and agricultural consumers. The coordinated regulation of the different biochemical pathways necessary to achieve this change receives considerable research attention. The MADS-box transcription factor RIPENING INHIBITOR (RIN) is an essential regulator of tomato (Solanum lycopersicum) fruit ripening but the exact mechanism by which it influences the expression of ripening-related genes remains unclear. Using a chromatin immunoprecipitation approach, we provide evidence that RIN interacts with the promoters of genes involved in the major pathways associated with observed and well-studied ripening phenotypes and phenomena, including the transcriptional control network involved in overall ripening regulation, ethylene biosynthesis, ethylene perception, downstream ethylene response, cell wall metabolism, and carotenoid biosynthesis. Furthermore, in the cases of ethylene and carotenoid biosynthesis, RIN interacts with the promoters of genes encoding rate-limiting activities. We also show that RIN recruitment to target loci is dependent on a normally functioning allele at the ripening-specific transcription factor COLORLESS NONRIPENING gene locus, further clarifying the relationship between these two ripening regulators.
Hormonal Regulation of Lateral Root Development in Arabidopsis Modulated byMIZ1and Requirement of GNOM Activity forMIZ1Function
Authors: Moriwaki Teppei , Miyazawa Yutaka , Kobayashi Akie , Uchida Mayumi , Watanabe Chiaki , Fujii Nobuharu , Takahashi Hideyuki
Published: September 2011

Plant organ development is important for adaptation to a changing environment. Genetic and physiological studies have revealed that plant hormones play key roles in lateral root formation. In this study, we show that MIZU-KUSSEI1 (MIZ1), which was identified originally as a regulator of hydrotropism, functions as a novel regulator of hormonally mediated lateral root development. Overexpression of MIZ1 (MIZ1OE) in roots resulted in a reduced number of lateral roots being formed; however, this defect could be recovered with the application of auxin. Indole-3-acetic acid quantification analyses showed that free indole-3-acetic acid levels decreased in MIZ1OE roots, which indicates that alteration of auxin level is critical for the inhibition of lateral root formation in MIZ1OE plants. In addition, MIZ1 negatively regulates cytokinin sensitivity on root development. Application of cytokinin strongly induced the localization of MIZ1-green fluorescent protein to lateral root primordia, which suggests that the inhibition of lateral root development by MIZ1 occurs downstream of cytokinin signaling. Surprisingly, miz2, a weak allele of gnom, suppressed developmental defects in MIZ1OE plants. Taken together, these results suggest that MIZ1 plays a role in lateral root development by maintaining auxin levels and that its function requires GNOM activity. These data provide a molecular framework for auxin-dependent organ development in Arabidopsis (Arabidopsis thaliana).
Diversifying State Supreme Courts
Authors: Goelzhauser Greg
Published: September 2011

Why do some states diversify their supreme courts sooner than others? Using original data on the first black and female state supreme court justices, I contend that political and institutional pressures influence when states diversify their high courts. The results suggest that selection systems, institutions affecting turnover, and the appointment of political minorities to the United States Supreme Court are associated with states seating their first black and female justices. The findings have implications for our understanding of the political and institutional circumstances that promote judicial diversity.
Increasing N Abundance in the Northwestern Pacific Ocean Due to Atmospheric Nitrogen Deposition
Authors: Kim Tae-Wook , Lee Kitack , Najjar Raymond G. , Jeong Hee-Dong , Jeong Hae Jin
Published: September 2011

Nitrogen deposition from the atmosphere has altered the nitrate:phosphorus ratio in the marginal seas of the northwestern Pacific Ocean.
Homemade ultrasound phantom for teaching identification of superficial soft tissue abscess
Authors: Lo Mark D , Ackley S Heath , Solari Patrick
Published: September 2011

Background

Point-of-care ultrasonography (POCUS) is often used to distinguish abscess from cellulitis in superficial soft tissue infections. With the increased use of POCUS in emergency medicine, it is important that training to use POCUS is enhanced by practice using phantom models.

Objective

To create an easily made, inexpensive, homemade phantom capable of simulating an abscess in superficial soft tissue infection.

Methods

Increasing amounts of Jell-O (Northfield, Illinois, USA) brand gelatin and sugar-free Metamucil (Cincinnati, Ohio, USA) brand psyllium hydrophilic mucilloid fibre were experimented with until a satisfactory model was achieved. Various liquids were injected into it to simulate superficial abscess formation. The desired goal was for the phantom to appear similar to superficial human soft tissue under ultrasound scan and to be firm enough to withstand pressure from an ultrasound probe scan. The goal for the simulated abscess was to appear as a hypoechoic space under ultrasound scan. A Sonosite M-Turbo (Bothell, Washington, USA) bedside ultrasound machine with linear array transducer probe was used for the ultrasound scans.

Results

The optimal homemade phantom incorporated 12 tablespoons of Jell-O and four tablespoons of Metamucil in one liter of water.

Conclusion

An easily made, inexpensive phantom model for instruction on identification of superficial skin abscess was achieved.
Immediate surge in female visits to the cardiac emergency department following the economic collapse in Iceland: an observational study
Authors: Guðjónsdóttir Guðlaug Rakel , Kristjánsson Már , Ólafsson Örn , Arnar Davíð O , Getz Linn , Sigurðsson Jóhann Ágúst , Guðmundsson Sigurður , Valdimarsdóttir Unnur
Published: September 2011

Objective

To study potential changes in attendance at emergency departments (ED) in Reykjavík immediately following the swift economic meltdown in Iceland in October 2008.

Methods

Using electronic medical records of the National University Hospital in Reykjavík, a population-based register study was conducted contrasting weekly attendance rates at Reykjavík ED (cardiac and general ED) during 10-week periods in 2006, 2007 and 2008. The weekly number of all ED visits (major track), with discharge diagnoses, per total population at risk were used to estimate RR and 95% CI of ED attendance in weeks 41–46 (after the 2008 economic collapse) with the weekly average number of visits during weeks 37–40 (before the collapse) as reference.

Results

Compared with the preceding weeks (37–40), the economic collapse in week 41 2008 was associated with a distinct increase in the total number of visits to the cardiac ED (RR 1.26; 95% CI 1.07 to 1.49), particularly among women (RR 1.41; 95% CI 1.17 to 1.69) and marginally among men (RR 1.15; 95% CI 0.96 to 1.37). A similar increase was not observed in week 41 at the general ED in 2008 or in either ED in 2007 or 2006. In week 41 2008, visits with ischaemic heart disease as discharge diagnoses (ICD-10: I20–25) were increased among women (RR 1.79; 95% CI 1.01 to 3.17) but not among men (RR 1.07; 95% CI 0.71 to 1.62).

Conclusion

The dramatic economic collapse in Iceland in October 2008 was associated with an immediate short-term increase in female attendance at the cardiac ED.
Behavior of the two-dimensional Ising model at the boundary of a half-infinite cylinder
Authors: Saint-Aubin Yvan , Arguin Louis-Pierre , Aurag Hassan
Published: September 2011

The critical two-dimensional Ising model is studied at the boundary of a half-infinite cylinder for the three regular lattices (square, triangular, and hexagonal). The probability of having precisely 2n spinflips at the boundary is computed as a function of the positions, ki, i = 1, 2, 3, …, 2n, of the spinflips. The limit when the mesh goes to zero is obtained. For the square lattice, the probability of having 2n spinflips, independent of their position, is computed at the critical temperature. As a byproduct, we recover De Coninck’s result showing that the limiting distribution of the number of spinflips is Gaussian and we give explicit expressions for its mean and variance. The results are obtained as consequences of Onsager’s solution and are rigorous.
Role of generalized Ricci dark energy on a Chameleon field in the emergent universe
Authors: Chattopadhyay Surajit , Debnath Ujjal
Published: September 2011

In this paper, we have considered the generalized Ricci dark energy (GRDE) and generalized holographic dark energy in the scenario of an emergent universe. Fractional energy density and deceleration parameters for GRDE were derived in an emergent universe scenario. Also, the role of GRDE on the chameleon field in the emergent universe scenario has been examined. Finally, the behaviours of the chameleon scalar field, [Formula: see text], corresponding potential, V, and associated function, f, were investigated in the presence of GRDE.