Distribution by Scientific Domains
Distribution within Chemistry

Kinds of Neutral

  • gender neutral
  • risk neutral

  • Terms modified by Neutral

  • neutral alumina
  • neutral amino acid transporter
  • neutral amino acids
  • neutral analyte
  • neutral antagonist
  • neutral aqueous solution
  • neutral carbohydrate
  • neutral complex
  • neutral compound
  • neutral condition
  • neutral cue
  • neutral density filter
  • neutral detergent fiber
  • neutral detergent fibre
  • neutral effect
  • neutral effects
  • neutral endopeptidase
  • neutral evolution
  • neutral exciton
  • neutral expectation
  • neutral face
  • neutral form
  • neutral fraction
  • neutral gas
  • neutral genetic differentiation
  • neutral genetic diversity
  • neutral genetic marker
  • neutral genetic variation
  • neutral hydrogen
  • neutral image
  • neutral ligand
  • neutral lipid
  • neutral locus
  • neutral loss
  • neutral marker
  • neutral microsatellite
  • neutral model
  • neutral models
  • neutral molecule
  • neutral mutation
  • neutral ph
  • neutral ph range
  • neutral ph.
  • neutral picture
  • neutral polysaccharide
  • neutral position
  • neutral process
  • neutral protease
  • neutral red
  • neutral salt
  • neutral solution
  • neutral species
  • neutral state
  • neutral states
  • neutral sterol
  • neutral stimulus
  • neutral sugar
  • neutral system
  • neutral theory
  • neutral trait
  • neutral water
  • neutral word

  • Selected Abstracts


    Every metaethical position commits you to the denial of some moral statement. So, for example, the metaethical position that there are no moral properties commits you to the denial of the (quite plausible) moral conjunction of 1) it is right to interfere violently when someone is wrongly causing massive suffering and 2) it is wrong to interfere violently when only non-moral properties are at stake. The argument generalizes to all metaethical positions. [source]

    Is the Impact of Public Investment Neutral Across the Regional Income Distribution?

    ECONOMIC GEOGRAPHY, Issue 3 2005
    Evidence from Mexico
    Abstract: This article investigates the contribution of public investment to the reduction of regional inequalities, with a specific application to Mexico. We examine the impact of public investment according to the position of each region in the conditional distribution of regional income by using quantile regression as an empirical technique. The results confirm the hypothesis that regional inequalities can indeed be attributed to the regional distribution of public investment; the observed pattern shows that public investment mainly helped to reduce regional inequalities among the richest regions. [source]

    Integrated microdevice for preconcentration and separation of a wide variety of compounds by electrochromatography

    ELECTROPHORESIS, Issue 3 2009
    Gaelle Proczek
    Abstract An integrated microdevice was developed to couple on-chip SPE to separation by channel electrochromatography. An acrylate-based monolith was synthesized within a glass microdevice by photoinitiated polymerization. It was used for both separation and preconcentration by direct injection on the head of the stationary phase or by confining the preconcentration step in a given zone of the stationary phase. The composition of the polymerization mixture was chosen to achieve a monolithic material containing both hydrophobic and charged moieties to ensure an electroosmotic flow for separation. As a consequence the extraction procedure occurs via hydrophobic and ionic interactions. Neutral, ionizable and charged compounds were successfully preconcentrated and separated within the microdevice through electrochromatographic mechanisms, highlighting the versatility of this device. The performance of the integrated microdevice was demonstrated with the preconcentration and separation of a mixture of PAHs for which a signal enhancement factor (SEF) of 270 was achieved within 120,s of preconcentration. In the case of charged and ionizable compounds, according to the electrolyte composition, contributions of both reverse-phase and ion-exchange mechanisms were used to perform effective electrochromatographic preconcentration. A SEF of 250 was obtained for the model-charged compound within 20,s of preconcentration. Finally, the potentials of on-chip preconcentrate and separate both neutral and ionized compounds have been demonstrated using a mixture of model compounds. [source]

    Neutral and Cationic Methylaluminium Complexes of 2-Anilinotropone Ligands: Synthesis, Characterization, and Reactivity toward Ethylene

    Daniela Pappalardo
    Abstract Some new aluminium complexes bearing bidentate monoanionic 2-anilinotroponate ligands have been synthesized and characterized. Reaction of 2-(2,6-diisopropylanilino)tropone or 2-(perfluoroanilino)tropone with AlMe3 (1 equiv.) gave, by methane elimination, compounds [2-(2,6-diisopropylanilino)tropone]AlMe2 (1) and [2-(perfluoroanilino)tropone]AlMe2 (2), respectively, as yellow solids. Reaction of 1 with 1 equiv. of the ligand furnished, by protodealumination of a second Al,CH3 bond, the [2-(2,6-diisopropylanilino)tropone]2AlMe derivative 3. The structure of 3 has been determined by single-crystal X-ray diffraction, showing a five-coordinate aluminium atom with a distorted trigonal-bipyramidal geometry. Compounds 1 and 3 underwent methyl abstraction reactions with B(C6F5)3; the resulting cationic species was trapped in the presence of THF in dichloromethane solution. The reactivity of the synthesized compounds in ethylene polymerisation has also been explored. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004) [source]

    Electroluminescence: (Highly Emitting Neutral Dinuclear Rhenium Complexes as Phosphorescent Dopants for Electroluminescent Devices) Adv.

    Neutral, dinuclear, highly luminescent rhenium(I) complexes are prepared and their photophysical and electrochemical properties investigated by Professor Luisa De Cola and co-workers. For the first time, electroluminescent devices, using a rhenium complex as dopant, obtained by sublimation and by solution processing are described. [source]

    Micellar Effects in Olefin Hydroformylation Catalysed by Neutral, Calix[4]arene-Diphosphite Rhodium Complexes

    Laure Monnereau
    Abstract The combination of calixarene-derived surfactants and neutral rhodium complexes containing a hemispherical "1,3-calix-diphosphite" ligand led to efficient catalysts for the hydroformylation of octene and other olefins in water. While the surfactants allowed the formation of micelles that dissolve both the catalyst and the alkene, thereby resulting in high olefin:rhodium ratios, the diphosphite provided a tight envelope about the catalytic centre able to drive the reaction towards the linear aldehydes. Best results in the hydroformylation of 1-octene were obtained when using [tetra(p -sulfonato)]-(tetra- n -butoxy)-calix[4]arene as surfactant. With this additive remarkable linear to branched aldehyde ratios of up to 62 were obtained, the corresponding activities being higher than those observed when operating in an organic solvent [turnover frequencies (TOFs) up to 630 mol(converted 1-octene), mol(Rh),1,h,1]. [source]

    Physiological Responses of Krishum (Iris lactea Pall. var. chinensis Koidz) to Neutral and Alkaline Salts

    Y. Wang
    Abstract The aims of this study were to compare the physiological responses of krishum (Iris lactea Pall. var. chinensis Koidz) to neutral and alkaline salt stress and identify and examine the mechanisms involved in plant response to salt treatments. In this study, biomass, ion accumulation (Na+, K+, Ca2+, Mg2+), organic solute (proline) concentration, rate of membrane electrolyte leakage (REL) and antioxidase activities including those of superoxide dismutase (SOD, EC, catalase (CAT, EC and peroxidase (POD, EC were investigated in krishum under different concentrations of NaCl, Na2CO3 and the mixture of the two salts in the same volume. All three treatments caused increases in Na+ concentration, proline content and REL and decreases in root Mg2+ and K+ content. Increased Ca2+ and antioxidase activities were observed at lower external Na+ concentrations. However, at higher external Na+ levels, decreased Ca2+ and antioxidase activities were detected. Alkaline salt resulted in more damage to krishum than neutral salt including lower SOD, POD and CAT activities and decreased proline content, relative to neutral salt. High Na+ and low K+ in krishum intensified ion toxicity under alkaline condition. Alkaline salt caused greater harm to plants than neutral salt, the primary reason of which might be the lower Ca2+ content in the plant under alkaline salt stress. [source]

    Effect of Gender on Communication of Health Information to Older Adults

    Jennifer L. Dearborn BA
    OBJECTIVES: To examine the effect of gender on three key elements of communication with elderly individuals: effectiveness of the communication, perceived relevance to the individual, and effect of gender-stereotyped content. DESIGN: Survey. SETTING: University of Connecticut Health Center. PARTICIPANTS: Thirty-three subjects (17 female); aged 69 to 91 (mean±standard deviation 82±5.4). MEASUREMENTS: Older adults listened to 16 brief narratives randomized in order and by the sex of the speaker (Narrator Voice). Effectiveness was measured according to ability to identify key features (Risks), and subjects were asked to rate the relevance (Plausibility). Number of Risks detected and determinations of plausibility were analyzed according to Subject Gender and Narrator Voice. Narratives were written for either sex or included male or female bias (Neutral or Stereotyped). RESULTS: Female subjects identified a significantly higher number of Risks across all narratives (P=.01). Subjects perceived a significantly higher number of Risks with a female Narrator Voice (P=.03). A significant Voice-by-Stereotype interaction was present for female-stereotyped narratives (P=.009). In narratives rated as Plausible, subjects detected more Risks (P=.02). CONCLUSION: Subject Gender influenced communication effectiveness. A female speaker resulted in identification of more Risks for subjects of both sexes, particularly for Stereotyped narratives. There was no significant effect of matching Subject Gender and Narrator Voice. This study suggests that the sex of the speaker influences the effectiveness of communication with older adults. These findings should motivate future research into the means by which medical providers can improve communication with their patients. [source]

    American Business and Political Power: Public Opinion, Elections and Democracy; Stuck in Neutral: Business and the Politics of Human Capital investment; Does Business Learn?

    Graham K. Wilson

    New Poly(sodium carboxylate)s Based on Saccharides, 1.

    Characterization of Ionic Allyl Glycoside Polymers, Synthesis
    Abstract New poly(sodium carboxylate)s, containing monosaccharide side groups with ether linkages to the main chain, are presented as substitutes for water-soluble homo- and copolymers of acrylic acid. Neutral and ionic allyl glycoside monomers, namely allyl- , - D -galactopyranoside and allyl- , - D -glucofuranosidurono-6,3-lactone, were synthesized by Fischer glycosidation. These monomers were copolymerized with maleic anhydride and itaconic acid in aqueous and nonaqueous solution. The corresponding copolymers with different structures, degrees of functionalization, and charge densities were characterized by 13C NMR spectroscopy, molecular-weight measurements, and intrinsic viscosity [,] determination. From these, the monomer reactivity ratios and Mark,Houwink relations were established (see Figure). Copolymerization curves of maleic acid copolymers 6 and 10. M1: mole fraction of allyl monomer 2, and 5, in the feed; m1: mole fraction of allyl monomer in the copolymer. The dashed line shows the course of an ideal alternating copolymerization (excepted: M1,=,0 mol-%, M1,=,100 mol-%). [source]

    The Influence of Testosterone Combined with a PDE5-inhibitor on Cognitive, Affective, and Physiological Sexual Functioning in Women Suffering from Sexual Dysfunction

    Flip Van Der Made MD
    ABSTRACT Introduction., Women with female sexual dysfunction have a reduced sensitivity to sexual stimuli. Activation of central mechanisms may open a window for phosphodiesterase type 5 inhibitors (PDE5) to be effective; as a consequence, the combination of testosterone and a PDE5 inhibitor will restore sexual function. Aim., To demonstrate that the combination of testosterone and vardenafil will increase the sensitivity for sexual stimuli and will improve the desire and arousal components of the sexual response. Methods., In a double-blind randomly assigned placebo-controlled crossover design, 28 women with desire and/or arousal disorder underwent four different drug treatments on four separate experimental days. A masked version of the emotional Stroop task with sexual and nonsexual words was used to measure sensitivity for sexual content. Neutral and erotic film fragments were used to determine genital,physiological and subjective reactions. Main Outcome Measures., A masked version of the emotional Stroop task, vaginal pulse amplitude. For subjective measurement, responses were collected continuously with a lever and two self-report measures were used. Results., In two subgroups, which were differentiated on the basis of their initial preconscious attentional bias for sexual cues, a different sexual response profile was found. In an initially low-attention group, preconscious attentional bias for sexual cues increased under the testosterone condition. In these women, the combination of testosterone and vardenafil caused an improvement in genital response and subjective indices of sexual functioning. In the group that had initially a high attention for sexual cues, preconscious attentional bias for sexual cues decreased under the condition of testosterone. In these women, the combination of testosterone and vardenafil had no effect on any of the indices of their sexual functioning. Conclusion., In women suffering from low sexual desire,associated with low attention for sexual cues,the combination of testosterone and vardenafil may be a promising new treatment. van der Made F, Bloemers J, Yassem WE, Kleiverda G, Everaerd W, van Ham D, Olivier B, Koppeschaar H, and Tuiten A. The influence of testosterone combined with a PDE5-inhibitor on cognitive, affective, and physiological sexual functioning in women suffering from sexual dysfunction. J Sex Med 2009;6:777,790. [source]

    ChemInform Abstract: Ab initio Search for Global Minimum Structures of the Novel B3Hy (y-= 4,7) Neutral and Anionic Clusters.

    CHEMINFORM, Issue 51 2009
    Jared K. Olson
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source]

    Density Functional Study of Small Neutral and Charged Silver Cluster Hydrides.

    CHEMINFORM, Issue 52 2006
    Shuang Zhao
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    Enantiodiscrimination and Enantiocontrol of Neutral and Cationic PtII Complexes Bearing the Tropos Biphep Ligand: Application to Asymmetric Lewis Acid Catalysis.

    CHEMINFORM, Issue 10 2006
    Koichi Mikami
    Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source]

    Efficient and Selective Oxidation of Thiols to Disulfides by 1,4-Diazabicyclo[2.2.2]octane-di-N-oxide-diperhydrate under Neutral and Heterogeneous Conditions.

    CHEMINFORM, Issue 4 2005
    Peyman Salehi
    No abstract is available for this article. [source]

    Formation of Silicon Analogues of Thio-isocyanic Acid, HNSiS, and Its Isomers by Neutral,Neutral Reactions of the Fragments: A Computational Study.

    CHEMINFORM, Issue 51 2004
    P. Raghunath
    No abstract is available for this article. [source]

    Catalytic Hydroamination of Alkynes and Norbornene with Neutral and Cationic Tantalum Imido Complexes.

    CHEMINFORM, Issue 45 2004
    Laura L. Anderson
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Structure, Energetics, Electronic, and Hydration Properties of Neutral and Anionic Al3O6, Al3O7, and Al3O8 Clusters

    CHEMINFORM, Issue 33 2004
    S. Gowtham
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Formation of P-Ylide under Neutral and Metal-Free Conditions: Transformation of Aziridines and Epoxides to Conjugated Dienes in the Presence of Phosphine.

    CHEMINFORM, Issue 25 2004
    Ren-Hua Fan
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Cyclopentene-Regioselective Palladium-Catalyzed Cycloisomerization under Neutral and Bis-cationic Reaction Conditions.

    CHEMINFORM, Issue 20 2003
    Andreas Heumann
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    [3 + 2] and [4 + 1] Cycloaddition Reactions of Fischer Alkoxy(alkenyl)carbene Complexes with Electronically Neutral 1,3-Dienes.

    CHEMINFORM, Issue 19 2003
    Jose Barluenga
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Selective Reduction of Fullerene C60 by Metals in Neutral and Alkaline Media.

    CHEMINFORM, Issue 18 2003
    Interaction of C60 with KOH
    Abstract For Abstract see ChemInform Abstract in Full Text. [source]

    Neutral and Oxidized Triisopropylsilyl End-Capped Oligothienoacenes: A Combined Electrochemical, Spectroscopic, and Theoretical Study

    Juan Aragó
    Abstract This work presents an analysis of the structural, electrochemical, and optical properties of a family of triisopropylsilyl end-capped oligothienoacenes (TIPS- Tn -TIPS, n=4,8) by combining cyclic voltammetry, spectroscopic techniques, and quantum-chemical calculations. TIPS- Tn -TIPS compounds form stable radical cations, and dications are only obtained for the longest oligomers (n=7 and 8). Oxidation leads to the quinoidization of the conjugated backbone, from which electrons are mainly extracted. The absorption and fluorescence spectra show partially resolved vibronic structures even at room temperature, due to the rigid molecular geometry. Two well-resolved vibronic progressions are observed at low temperatures due to the vibronic coupling, with normal modes showing wavenumbers of ,1525 and ,480,cm,1. Optical absorption bands display remarkable bathochromic dispersion with the oligomer length, indicative of the extent of , conjugation. The optical properties of the oxidized compounds are characterized by in situ UV/Vis/NIR spectroelectrochemistry. The radical cation species show two intense absorption bands emerging at energies lower than in the neutral compounds. The formation of the dication is only detected for the heptamer and the octamer, and shows a new band at intermediate energies. Optical data are interpreted with the help of density functional theory calculations performed at the B3LYP/6-31G** level, both for the neutral and the oxidized compounds. [source]

    Electronic Structure and Bonding in Neutral and Dianionic Boradiphospholes: R,BC2P2R2 (R=H, tBu, R,=H, Ph)

    Dandamudi Usharani
    Abstract Classical and non-classical isomers of both neutral and dianionic BC2P2H3 species, which are isolobal to Cp+ and Cp,, are studied at both B3LYP/6-311++G(d,p) and G3B3 levels of theory. The global minimum structure given by B3LYP/6-311++G(d,p) for BC2P2H3 is based on a vinylcyclopropenyl-type structure, whereas BC2P2H32, has a planar aromatic cyclopentadienyl-ion-like structure. However, at the G3B3 level, there are three low-energy isomers for BC2P2H3: 1),tricyclopentane, 2),nido and 3),vinylcyclopropenyl-type structures, all within 1.7,kcal,mol,1 of each other. On the contrary, for the dianionic species the cyclic planar structure is still the minimum. In comparison to the isolobal Cp+ and HnCnP5,n+ isomers, BC2P2H3 shows a competition between ,-delocalised vinylcyclopropenyl- and cluster-type structures (nido and tricyclopentane). Substitution of H on C by tBu, and H on B by Ph, in BC2P2H3 increases the energy difference between the low-lying isomers, giving the lowest energy structure as a tricyclopentane type. Similar substitution in BC2P2H32, merely favours different positional isomers of the cyclic planar geometry, as observed in 1),isoelectronic neutral heterodiphospholes EtBu2C2P2 (E=S, Se, Te), 2),monoanionic heterophospholyl rings EtBu2C2P2 (E=P,, As,, Sb,) and 3),polyphospholyl rings anions tBu5,nCnP5,n (n=0,5). The principal factors that affect the stability of three-, four-, and five-membered ring and acyclic geometrical and positional isomers of neutral and dianionic BC2P2H3 isomers appear to be: 1),relative bond strengths, 2),availability of electrons for the empty 2p boron orbital and 3),steric effects of the tBu groups in the HBC2P2tBu2 systems. [source]

    Unexpected Aggregation of Neutral, Xylene-Cored Dinuclear GdIII Chelates in Aqueous Solution

    Jérôme Costa Dr.
    Abstract We have synthesized ditopic ligands L1, L2, and L3 that contain two DO3A3, metal-chelating units with a xylene core as a noncoordinating linker (DO3A3, = 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate; L1 = 1,4-bis{[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane-1-yl]methyl}benzene; L2 = 1,3-bis{[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane-1-yl]methyl}benzene; L3 = 3,5-bis{[4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododecane-1-yl]methyl}benzoic acid). Aqueous solutions of the dinuclear GdIII complexes formed with the three ligands have been investigated in a variable-temperature, multiple-field 17O NMR and 1H relaxivity study. The 17O longitudinal relaxation rates measured for the [Gd2L1,3(H2O)2] complexes show strong field dependence (2.35,9.4 T), which unambiguously proves the presence of slowly tumbling entities in solution. The proton relaxivities of the complexes, which are unexpectedly high for their molecular weight, and in particular the relaxivity peaks observed at 40,50 MHz also constitute experimental evidences of slow rotational motion. This was explained in terms of self-aggregation related to hydrophobic interactions, , stacking between the aromatic linkers, or possible hydrogen bonding between the chelates. The longitudinal 17O relaxation rates of the [Gd2L1,3(H2O)2] complexes have been analysed with the Lipari,Szabo approach, leading to local rotational correlation times of 150,250 ps and global rotational correlation times of 1.6,3.4 ns (cGd: 20,50 mM), where is attributed to local motions of the Gd segments, while describes the overall motion of the aggregates. The aggregates can be partially disrupted by phosphate addition; however, at high concentrations phosphate interferes in the first coordination sphere by replacing the coordinated water. In contrast to the parent [Gd(DO3A)(H2O)1.9], which presents a hydration equilibrium between mono- and dihydrated species, a hydration number of q = 1 was established for the [Ln2L1,3(H2O)2] chelates by 17O chemical shift measurements on Ln = Gd and UV/Vis spectrophotometry for Ln = Eu. The exchange rate of the coordinated water is higher for [Gd2L1,3(H2O)2] complexes ( = 7.5,12.0×106 s,1) than for [Gd(DOTA)(H2O)],. The proton relaxivity of the [Gd2L1,3(H2O)2] complexes strongly decreases with increasing pH. This is related to the deprotonation of the inner-sphere water, which has also been characterized by pH potentiometry. The protonation constants determined for this process are logKOH = 9.50 and 10.37 for [Gd2L1(H2O)2] and [Gd2L3(H2O)2], respectively. [source]

    Isotropic 13C Hyperfine Coupling Constants Distinguish Neutral from Anionic Ubiquinone-Derived Radicals,

    CHEMPHYSCHEM, Issue 18 2009
    Scott E. Boesch
    A radical notion: Calculated isotropic 13C hyperfine coupling constants are distinctly different for the anionic ubisemiquinone model UQ., (picture, left) rather than the protonated UQH. (picture, right) and can distinguish between the two in electron transfer proteins such as cytochrome bo3, cytochrome bc1, or photosynthetic reaction centers. [source]


    Moshe Koppel
    Most research on learning to identify sentiment ignores "neutral" examples, learning only from examples of significant (positive or negative) polarity. We show that it is crucial to use neutral examples in learning polarity for a variety of reasons. Learning from negative and positive examples alone will not permit accurate classification of neutral examples. Moreover, the use of neutral training examples in learning facilitates better distinction between positive and negative examples. [source]


    Alistair Kennedy
    We present two methods for determining the sentiment expressed by a movie review. The semantic orientation of a review can be positive, negative, or neutral. We examine the effect of valence shifters on classifying the reviews. We examine three types of valence shifters: negations, intensifiers, and diminishers. Negations are used to reverse the semantic polarity of a particular term, while intensifiers and diminishers are used to increase and decrease, respectively, the degree to which a term is positive or negative. The first method classifies reviews based on the number of positive and negative terms they contain. We use the General Inquirer to identify positive and negative terms, as well as negation terms, intensifiers, and diminishers. We also use positive and negative terms from other sources, including a dictionary of synonym differences and a very large Web corpus. To compute corpus-based semantic orientation values of terms, we use their association scores with a small group of positive and negative terms. We show that extending the term-counting method with contextual valence shifters improves the accuracy of the classification. The second method uses a Machine Learning algorithm, Support Vector Machines. We start with unigram features and then add bigrams that consist of a valence shifter and another word. The accuracy of classification is very high, and the valence shifter bigrams slightly improve it. The features that contribute to the high accuracy are the words in the lists of positive and negative terms. Previous work focused on either the term-counting method or the Machine Learning method. We show that combining the two methods achieves better results than either method alone. [source]

    Correlation of Density Pedestal Width and Neutral Penetration Length

    X. Q. Xu
    Abstract Pedestal studies in DIII-D and MAST find good correlation between the width of the H-mode density barrier and the neutral penetration length [1, 2]. These results suggest that the width may be set by the combined effects of neutrals and plasma transport. This paper is a report on fluid simulations of boundary plasma using the BOUT code[3] with a neutral source added. Thus both neutral and plasma physics are treated. The plasma transport is self-consistently driven by boundary turbulence due to the resistive X-point mode, while neutrals are described by a simple analytic model. The plasma profiles are evolved on the same time scale as the turbulence for the given heat source from the core plasma and particle source from the neutrals. For prescribed neutral profiles, we find the formation of a density pedestal inside the separatrix in the L-mode even though the calculated plasma diffusion coefficients are almost radially constant and without the formation of a temperature pedestal. These results support the hypothesis that particle fueling can provide the dominant control for the size of the H-mode density barrier. The width of the density barrier decreases as the pedestal density increases which is also consistent with experimental data. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

    The Ideological Implications of Using "Educational" Film to Teach Controversial Events

    CURRICULUM INQUIRY, Issue 3 2009
    ABSTRACT Use of media in today's classrooms, from feature and documentary film to news clips streamed via the Web, has grown exponentially. Film can be a powerful medium for teaching and learning, but is often viewed as a neutral source of information. This collective case study focuses on two teachers who use documentary film to teach about controversial events, with the goal of better understanding teacher selection and use of film as part of pedagogy and the experiences of students who are engaged in deliberative activities with film. In this case, teachers utilized film to help students examine two controversial events in U.S. history, the use of atomic weapons against Japan at the end of World War II and the role of the United States in Vietnam. These cases illustrate a tension that many teachers, who want to engage students in deliberative activities but who also want students to adopt particular moral or political stances, face in today's classrooms. The teachers in these cases utilize film as a neutral source for students to use as evidence for taking a position, despite the value-laden perspectives included in the films, perspectives that aligned with the teachers' own political beliefs. Other findings include student inability to recognize the perspectives in documentary films, the epistemic stances of teachers and students that documentaries are accurate and neutral, and the characteristics of students who are better equipped to recognize ideological perspectives. Implications for teachers, teacher educators, and especially democratic and social studies education researchers are explored. [source]