bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and characterization of multiblock copolymers composed of poly(5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one) outer blocks and poly(L‐lactide) inner blocks
Authors: Messman Jamie M. , Storey Robson F.
Published: October 2006

Ethylene glycol (EG) initiated, hydroxyl‐telechelic poly(L‐lactide) (PLLA) was employed as a macroinitiator in the presence of a stannous octoate catalyst in the ring‐opening polymerization of 5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one (MBC) with the goal of creating A–B–A‐type block copolymers having polycarbonate outer blocks and a polyester center block. Because of transesterification reactions involving the PLLA block, multiblock copolymers of the A–(B–A)n–B–A type were actually obtained, where A is poly(5‐methyl‐5‐benzyloxycarbonyl‐1,3‐dioxan‐2‐one), B is PLLA, and n is greater than 0. 1H and 13C NMR spectroscopy of the product copolymers yielded evidence of the multiblock structure and provided the lactide sequence length. For a PLLA macroinitiator with a number‐average molecular weight of 2500 g/mol, the product block copolymer had an n value of 0.8 and an average lactide sequence length (consecutive C6H8O4 units uninterrupted by either an EG or MBC unit) of 6.1. For a PLLA macroinitiator with a number‐average molecular weight of 14,400 g/mol, n was 18, and the average lactide sequence length was 5.0. Additional evidence of the block copolymer architecture was revealed through the retention of PLLA crystallinity as measured by differential scanning calorimetry and wide‐angle X‐ray diffraction. Multiblock copolymers with PLLA crystallinity could be achieved only with isolated PLLA macroinitiators; sequential addition of MBC to high‐conversion L‐lactide polymerizations resulted in excessive randomization, presumably because of residual L‐lactide monomer. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6817–6835, 2006
Highly substituted poly(2,3‐diphenyl‐1,4‐phenylenevinylene) derivatives having bulky phenyl and fluorenyl pendant groups: Synthesis, characterization, and electro‐optical properties
Authors: Yang Sheng‐Hsiung , Li Hsing‐Chuan , Chen Chien‐Kai , Hsu Chain‐Shu
Published: October 2006

Two series of poly(2,3‐diphenyl‐1,4‐phenylenevinylene) (DP‐PPV) derivatives containing multiple bulky substituents were synthesized. In the first series, two different groups were incorporated on C‐5,6 positions of the phenylene moiety to increase steric hindrance and to obtain blue‐shifted emissions. In the second series, bulky fluorenyl groups with two hexyl chains on the C‐9 position were introduced on two phenyl pendants to increase the solubility as well as steric hindrance to prevent close packing of the main chain. Polymers with high molecular weights and fine‐tuned electro‐optical properties were obtained by controlling the feed ratio of different monomers during polymerization. The maximum photoluminescent emissions of the thin films are located between 384 and 541 nm. Cyclic voltammetric analysis reveals that the band gaps of these light‐emitting materials are in the range from 2.4 to 3.3 eV. A double‐layer EL device with the configuration of ITO/PEDOT/P4/Ca/Al emitted pure green light with CIE′1931 at (0.24, 0.5). Using copolymer P6 as the emissive layer, the maximum luminescence and current efficiency were both improved when compared with the homopolymer P4. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6738–6749, 2006
Novel amphiphilic graft copolymers bearing hydrophilic poly(acrylic acid) backbones and hydrophobic poly(butyl methacrylate) side chains
Authors: Peng Dan , Lu Guolin , Zhang Sen , Zhang Xiaohuan , Huang Xiaoyu
Published: October 2006

A novel amphiphilic graft copolymer consisting of hydrophilic poly(acrylic acid) backbones and hydrophobic poly(butyl methacrylate) side chains was synthesized by successive atom transfer radical polymerization followed by hydrolysis of poly‐(methoxymethyl acrylate) backbone. A grafting‐from strategy was employed for the synthesis of graft copolymers with narrow molecular weight distributions (polydispersity index < 1.40). Hydrophobic side chains were connected to the backbone through stable CC bonds instead of ester connections. Poly(methoxymethyl acrylate) backbone was easily hydrolyzed to poly(acrylic acid) backbone with HCl without affecting the hydrophobic side chains. The amphiphilic graft copolymer could form stable micelles in water. The critical micelle concentration in water was determined by a fluorescence probe technique. The morphology of the micelles was preliminarily explored with transmission electron microscopy and was found to be spheres. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6857–6868, 2006
Phosphorylated copolymers containing pendant, crosslinkable spiro orthoester moieties
Authors: Canadell J. , Hunt B. J. , Cook A. G. , Mantecón A. , Cádiz V.
Published: October 2006

The synthesis of a novel spiro orthoester containing monomer, 1,4,6‐trioxaspiro[4.4]‐2‐nonylmethyl acrylate, is presented. This monomer was polymerized via a free‐radical system to yield the homopolymer and a series of copolymers with phosphorus‐containing comonomers. Diethyl vinyl phosphonate, allyldiphenylphosphine oxide, and diethyl(methacryoyoxymethyl)phosphonate were used in various feed ratios to produce copolymers with different phosphorous concentrations containing crosslinkable spiro orthoester side‐chain units. The crosslinking of the polymers was performed cationically with ytterbium triflate, and in all cases, the expansion of the polymer was observed. Moreover, the incorporation of phosphorus into the copolymers increased the limiting oxygen indices, regardless of the percentage of phosphorus used. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6728–6737, 2006
A mitochondrial‐targeting signal is present in the non‐catalytic domain of the MELK protein kinase
Authors: Chartrain Isabelle , Blot Joëlle , Lerivray Hubert , Guyot Nicolas , Tassan Jean‐Pierre
Published: October 2006

MELK is a cell cycle‐regulated protein kinase involved in cell cycle progression, proliferation, tumor growth and mRNA splicing. MELK is localized in the cytoplasm and the nucleus during interphase and at the cell cortex during anaphase and telophase. In this report, we show that the regulatory domain of Xenopus MELK when tagged at its C‐terminus with the green fluorescent protein (GFP), co‐localizes with mitochondria in Xenopus XL2 cells. Significantly, the presence of a mitochondrial targeting signal at the N‐terminus of this fusion protein was predicted by bioinformatics analyses. In agreement with previous reports on mitochondrial proteins, placing the GFP at the N‐terminus inhibited the mitochondrial targeting of the MELK fragment and, furthermore, the regulatory domain without a tag co‐localizes with mitochondria. These results demonstrate the presence of a mitochondrial targeting signal at the N‐terminus of the MC domain of MELK. This mitochondrial targeting signal was also functional in human HeLa cells.
Functional characterization of the promoter for the mouse SPTLC2 gene, which encodes subunit 2 of serine palmitoyltransferase
Authors: Linn Stephen C. , Andras Lindsay M. , Kim Hee-Sook , Wei Jia , Nagiec M. Marek , Dickson Robert C. , Merrill Alfred H.
Published: October 2006

A series of luciferase reporter constructs was prepared from a 1035‐bp fragment of mouse genomic DNA flanking the 5′‐coding sequence for the SPTLC2 subunit of serine palmitoyltransferase, the initial enzyme of de novo sphingolipid biosynthesis. The full‐length DNA fragment promoted strong reporter gene expression in NIH3T3 cells while deletion and site‐directed mutagenesis indicated that the proximal 335 bp contain initiator and downstream promoter elements, two proximal GC boxes that appear to stimulate transcription in a cooperative manner, and several additional elements whose activity cannot be accounted for by known factor binding sites. These findings provide insight into the control mechanisms for transcription of mammalian SPTLC2.
Variation in the catchability of yellow perch (Perca flavescens) in the fisheries of Lake Erie using a Bayesian error-in-variable approach
Authors: Jiao Yan , Reid Kevin , Nudds Tom
Published: October 2006

Catch per unit effort (cpue) from fisheries, and abundance or biomass indices from fishery-independent surveys are often used to infer the dynamics of exploited populations. To do this, cpues and survey indices are usually assumed to be proportional to population size or biomass. Four sources of data on the cpue of yellow perch (Perca flavescens) in Lake Erie were available to evaluate this assumption: commercial gillnet and trapnet fisheries, an angling fishery, and a fishery-independent gillnet survey. The relationships between fisheries cpue and population biomass (estimated from an age-structured model), and between fisheries and survey cpues were analysed by error-in-variable (EIV) models because of the absence of independent estimates of population size. Cpues were not proportional to population size, estimated by biomass. Catchabilities varied widely among fisheries (gear types), time period, and areas (management units) within Lake Erie. A spatial EIV model showed that the migrations among management units were considerable. The whole-lake spatial EIV model showed that cpues were not proportional to population size.
Temperate grassland: key developments in the last century and future perspectives
Authors: HOPKINS A. , WILKINS R. J.
Published: October 2006

In temperate regions, grassland provides most of the feed requirements for ruminants. Its management has implications for landscape and environmental quality as well as agricultural production. The present paper reviews the key developments in grassland management, production and utilization during the 20th century, focusing primarily on the UK but drawing on research and practice from other areas. Increased production from grassland has arisen from improved understanding of soil and plant nutrition, plant physiology and cultivar improvement, while improved understanding of feed evaluation, ruminant nutrition, grazing management and silage technology have contributed to increased utilization of grassland under grazing and cutting. Permanent and long-term swards occupied most of the total grassland area at both the beginning and end of the century, but inputs of nitrogen resulted in greatly increased herbage production, particularly from the 1960s; this, combined with reseeding and early cutting for silage, led to reduced botanical diversity with ryegrass dominance in lowland areas. Forage legumes were highly regarded at the beginning of the century, then decreased in many areas, but are again recognized as having a key role in low- and medium-input systems. Recognition of the environmental implications of grassland management has increased since the 1980s. This includes the need to reduce nutrient emissions in grassland agriculture, and also the role of grassland in biodiversity protection, carbon sequestration and landscape quality. Research is increasingly focused on addressing these issues and on integrating agricultural management with environmental protection. Improved nutrient management, legume-based systems and agri-environmental schemes, as well as interest in the food quality attributes of particular systems and grassland communities, are important in the medium term. In the longer term the effects of population increase, competition for other land uses and the impacts of climate change could impact on global food supplies and affect future grassland management in the temperate zones.
THE ASSOCIATIONS BETWEEN SOCIOECONOMIC STATUS, ALLOSTATIC LOAD AND MEASURES OF HEALTH IN OLDER TAIWANESE PERSONS: TAIWAN SOCIAL ENVIRONMENT AND BIOMARKERS OF AGING STUDY
Authors: HU PEIFENG , WAGLE NAVEED , GOLDMAN NOREEN , WEINSTEIN§ MAXINE , SEEMAN TERESA E.
Published: October 2006

Data from a national representative sample of 1023 elderly and near-elderly Taiwanese were used to explore whether allostatic load is associated with health outcomes and mediates the association between socioeconomic status and health in a non-Western population. The information collected included: demographic characteristics; allostatic load scores; socioeconomic status, measured by education and income; health behaviours; health-related variables, including self-rated health, basic activities of daily living difficulties, instrumental activities of daily living difficulties, and physical activity difficulties. The adjusted prevalent odds ratios of higher allostatic load level were 1·25 (95% CI: 1·00, 1·56) for reporting one level worse in self-rated health and 1·43 (95% CI: 1·14, 1·82) for reporting one more physical activity difficulty. There were significant associations of lower education or less income with worse self-rated health and more difficulties with physical functioning. The associations between education, income and health status are not mediated by the conventional ten-point measure of allostatic load in older Taiwanese adults.
EVIDENCE FOR ASSORTATIVE MATING ON DIGIT RATIO (2D:4D), A BIOMARKER FOR PRENATAL ANDROGEN EXPOSURE
Authors: VORACEK MARTIN , DRESSLER STEFAN G. , MANNING JOHN T.
Published: October 2006

The second-to-fourth digit ratio (2D:4D) presents an anatomical sex difference in humans. On average, men tend to have lower 2D:4D compared with women. There is fairly strong evidence for a role of the 2D:4D ratio as a biomarker for the organizational (permanent) effects of prenatal testosterone on the brain and behaviour. Recently, an accumulating research programme has shown 2D:4D to be related to a multitude of sex-dependent, hormonally influenced biosocial traits and phenotypes which reach into the domains of ability, behaviour, fertility, health, personality and sexuality. This study investigated the degree of assortative mating (spousal similarity) in a sample of 239 native Austrian couples of parental or grandparental age, all of them having reproduced. Results included: (i) significant spousal correlations of +0·19 and +0·18 for right-hand and left-hand 2D:4D, respectively, and +0·24 for average 2D:4D; (ii) no assortative mating effect on the right-minus-left difference in 2D:4D; (iii) indications consistent with a possible generational decrease of spousal similarity in 2D:4D; (iv) a prevalence of couples with a lower right-hand 2D:4D observed in the husband compared with his wife; and (v) relations of spousal 2D:4D patterns to spousal age differences, such that matings of men with more male-typical trait expressions (namely, a generally low right-hand 2D:4D or showing a lower right-minus-left 2D:4D difference than their wives) implicated larger male-minus-female age differences, i.e. younger wives. It is argued that assortative mating on 2D:4D operates indirectly and may be mediated through the assortment on other, more perceptible, physical traits and psychological phenotypes that entertain associations with 2D:4D and are relevant for courtship and mate choice.
INTELLIGENCE DIFFERENCES BETWEEN EUROPEAN AND ORIENTAL JEWS IN ISRAEL
Authors: DAVID HANNA , LYNN RICHARD
Published: October 2006

A number of studies have found that Ashkenazi Jews in the United States have a high average IQ. It has been proposed by Cochran, Hardy and Harpending (2006) that this can be explained by the occupational constraints imposed on the Ashkenazi for many centuries in Europe, when they were largely confined to money-lending. They propose that this selected for the high verbal and mathematical intelligence that has several times been found in American Ashkenazim. The current study investigates how far this theory holds for European and Oriental Jews in Israel. A review of studies shows that Oriental Jews in Israel have an average IQ 14 points lower than that of European (largely Ashkenazi) Jews. It is proposed that this difference can be explained in terms of the Cochran, Hardy and Harpending theory because Oriental Jews were permitted to engage in a much wider range of occupations and hence did not come under the selection pressure to develop the high verbal and mathematical intelligence that was present for Ashkenazim.
Brecht, the Berliner Ensemble, and the British Government
Authors: Smith James
Published: October 2006

It is well known that Bertolt Brecht, during his time in the United States of America, attracted the surveillance of anti-communist forces, with Brecht's sly testimony to the House Committee on Un-American Activities becoming one of his most famous public performances. Recently declassified files from Her Majesty's Government reveal that Britain, too, undertook extensive campaigns to monitor and censor Brecht and the Berliner Ensemble. James Smith considers material from British governmental agencies such as MI5, the Foreign Office, and the Cabinet Office, which detail the activities undertaken by the British government concerning Brecht and the Ensemble. Such activities took the form not only of monitoring Brecht and his circle, both in Britain and overseas, but also of active attempts to block the visits of Brecht and the Ensemble, and to pressure theatre festivals and promoters into refusing to facilitate tours. The issue of the Berliner Ensemble caused debates at the highest levels of Whitehall, influencing the delicate area of British and NATO policy regarding the diplomatic status of East Germany during the Cold War. James Smith has completed a doctoral dissertation at Cambridge examining the influence of Brecht on British theatre. He currently teaches modern drama in the Faculty of Education and at Homerton College, Cambridge.
Theatre and the Presidential Debates: the Role of Performance in Voter Choice
Authors: Watson Ian
Published: October 2006

The fictionalized account in the recent film The Queen of Tony Blair's coaching of Her Majesty into a more voter-friendly response to the death of Princess Diana, largely through the medium of television, is a pertinent reminder of how the presentation of self on television subtly modifies the presentation of self in everyday life. In this article, Ian Watson considers how the now-ritualized debates between the main contenders in American presidential elections are stage-managed to enhance what their supporters suppose to be their candidate's most sympathetic features – supposedly learning the lessons of the first such debate, between John F. Kennedy and Richard Nixon, which displayed Nixon in such an unappealing light. However, what are ostensibly strengths or weaknesses may be read as quite other by an audience attuned to reading signifiers in film or television drama – or simply empathic towards what others perceive as failings, as in the case of reactions to George W. Bush's inarticulacies, awkward mannerisms, and failed jokes, which some read not as signs of ineptness but of an endearing humanity. Ian Watson, who is a Contributing Editor of New Theatre Quarterly, teaches at Rutgers University, Newark, where he is the Acting Chair of the Department of Visual and Performing Arts. He is author of Towards a Third Theatre: Eugenio Barba and the Odin Teatret (Routledge, 1993) and of Negotiating Cultures: Eugenio Barba and the Intercultural Debate (Manchester University Press, 2002). He edited Performer Training across Cultures (Routledge, 2001), and has published numerous articles on theatre in scholarly journals.
‘Concentration’ and Awareness in Psychophysical Training: the Practice of Elsa Gindler
Authors: Loukes Rebecca
Published: October 2006

In this article Rebecca Loukes explores the practice of German psychophysical awareness practitioner Elsa Gindler (1885–1961), whose work influenced twentieth-century performance in a range of ways, but has not previously been documented in this context. Loukes situates Gindler's training and early work amongst key early twentieth-century Gymnastik practitioners before tracing developments in her life and work, drawing from Gindler's 1926 article, her unpublished class notes, and her students' memories. She discusses what Gindler meant by cultivating a state of ‘concentration’, and how this related to breathing, tension, and relaxation, both in the studio and daily life. She then indicates how this can usefully be applied to contemporary pre-performance training or work on the ‘beginning state of the actor’. Rebecca Loukes is a practitioner, performer, and researcher in the area of actor training and psychophysical awareness. She has been training in practices derived from Gindler's work for over ten years. Her recent writing includes ‘Body Awareness in Performer Training: the Hidden Legacy of Gertrud Falke-Heller (1891–1984)’ for Dance Research Journal (in press). She is Lecturer in Performance Practice at the University of Exeter.
Does tree size influence timing of flowering in Cerberiopsis candelabra (Apocynaceae), a long-lived monocarpic rain-forest tree?
Authors: Read Jennifer , Sanson Gordon D. , Jaffré Tanguy , Burd Martin
Published: October 2006

Cerberiopsis candelabra is a long-lived monocarpic rain-forest tree endemic to New Caledonia that shows mass flowering across a substantial proportion of a population, and across a substantial number of populations. We investigated the relationship between tree size and flowering (and subsequent dying) across 18 populations from the flowering event of 2003 in order to understand the role of possible size thresholds for flowering in the life history and regeneration ecology of this monocarpic species. There was a strong positive correlation between trunk diameter and the incidence of flowering when population data were combined. However, the relationship between size and flowering was complex in that flowering occurred across a wide range of tree sizes, with almost complete overlap in size between flowering (5–79 cm dbh) and non-flowering trees (5–64 cm dbh), and with large trees in both the flowering and non-flowering state in the same population. In about half the populations studied there was no significant difference in mean trunk diameter of flowering and non-flowering trees. Nonetheless, we suggest that tree size may play a fundamental role in the life history and regeneration ecology of this species. The seedlings appear to be relatively shade-intolerant and dependent on large canopy gaps for recruitment. A significant effect of mass flowering and subsequent death of multiple large trees is the potential to form large canopy gaps and enhance seedling survival, as the gap is temporally linked with seed germination. However, it is unclear why there is such a large size range of flowering trees, i.e. whether this is just a consequence of the proximate cue, or whether the optimal size for flowering does indeed vary among individuals.
Recovery and succession of epiphytes in upper Amazonian fallows
Authors: Benavides Ana-Maria , Wolf Jan H. D. , Duivenvoorden Joost F.
Published: October 2006

The species richness, number of plants, biomass, and species composition of holo- and hemi-epiphytes were recorded in fifty-six 0.04-ha plots, distributed over forest fallows of 2–30 y old and mature forests in lowland Amazonia (Amacayacu National Park, Colombia). A total of 9190 epiphytic plants representing 162 species were recorded on 4277 phorophytes. Seventy species were classified as holo-epiphyte and 85 as hemi-epiphyte. Aroids were most diverse (58 species) and represented 76% of the total recorded biomass. Anemochory was more dominant among holo-epiphytes and zoochory among hemi-epiphytes. The species richness, density and biomass of both holo- and hemi-epiphytes increased significantly from young fallows to old fallows and mature forests. Hemi-epiphytes had greater density and biomass than holo-epiphytes. In canonical ordination, forest age did not relate to the species composition of holo-epiphytes. However, for hemi-epiphytes, the age effect was significant, suggesting that species turnover takes place in the ageing fallows.
Food niche overlap between sympatric potential competitors increases with habitat alteration at different trophic levels in rain-forest reptiles (omnivorous tortoises and carnivorous vipers)
Authors: Luiselli Luca
Published: October 2006

Comparisons of sympatric reptile species were used to assess the variation in niche overlap for food between potential competitors at different trophic levels. Omnivorous tortoises and carnivorous vipers inhabiting the rain-forest region of West Africa were used as study models. Food niche overlap between species increased with habitat alteration in both the independent study systems: tortoises (Kinixys homeana and Kinixys erosa) and vipers (Bitis gabonica and Bitis nasicornis) showed lower values of Pianka's niche overlap index in the pristine habitat than in the altered habitat, and these differences in overlap values did not depend on chance after Monte Carlo simulations. There were higher inter-habitat food niche overlaps within-species than between-species. Permutation tests (assessed after 5000 iterations) revealed that, for both study systems, the P-values became significantly smaller with fewer resource states, thus showing the niche overlap between species really increases after habitat alteration. The observed increases in food niche overlap between species accomplished with rain-forest habitat degradation in turn may be predicted to have cumulative effects on reducing the level of forest biodiversity.
The attributive possessive in Moroccan Arabic spoken by young bilinguals in the Netherlands and their peers in Morocco
Authors: BOUMANS LOUIS
Published: October 2006

Moroccan Arabic has two competing syntactic constructions for possessive marking: a synthetic one and an analytic one. The distribution of these constructions is investigated in semi-spontaneous narratives (frog stories) from four Moroccan cities and from the diaspora community in the Netherlands. This distribution is found to depend very much on the individual lexical items that head the construction, and on the form of the dependent, pronominal dependents favouring the synthetic form. Regional variation in Morocco is linked to the sociolinguistic history of the regions. The northern town of Tangier, where language contact with Berber (and Late Latin) had the greatest impact on the formation of Arabic dialects, shows the greatest preference for the analytic genitive. The immigrant community in the Netherlands shows an increased preference for the analytic form in comparison with their peers in Morocco. This concerns possessives with NP dependents in particular, which suggests a direct influence of Dutch as the socially dominant language.
Naming interlingual homographs: Variable competition and the role of the decision system
Authors: SMITS ERICA , MARTENSEN HEIKE , DIJKSTRA TON , SANDRA DOMINIEK
Published: October 2006

To investigate decision level processes involved in bilingual word recognition tasks, Dutch–English participants had to name Dutch–English homographs in English. In a stimulus list containing items from both languages, interlingual homographs yielded longer naming latencies, more Dutch responses, and more other errors in both response languages if they had a high-frequency Dutch reading. Dutch naming latencies were slower than or equally slow as English naming latencies. In a stimulus list containing only English words and homographs, there was no homograph effect in naming latencies, although homographs did elicit more errors than control words. The results are interpreted as the consequence of list-induced variability in the competition between lexical items of the two languages involved. In addition, two additional decision processes have to be assumed: a language check, and a response deadline for non-target-language responses.
Lexical activation of cross-language syntactic priming
Authors: SALAMOURA ANGELIKI , WILLIAMS JOHN N.
Published: October 2006

Cross-language (L1-to-L2) syntactic priming is the repetition of utterance structure from one language to another independently of meaning and has motivated models of language-shared representations of L1-L2 equivalent structures (Salamoura and Williams, submitted; Schoonbaert, Hartsuiker and Pickering, submitted). These models assume that the phenomenon is the result of residual activation of syntactic features encoding verb structural preferences and they, therefore, predict its initiation by a single verb prime (cf. Pickering and Branigan, 1998, for L1). This prediction was confirmed in a sentence completion task where we obtained syntactic priming from L1 Dutch to L2 English with Prepositional Object (PO) and Double Object (DO) datives upon presentation of single Dutch verbs that take either PO or DO only.
Anthropogenic emissions of nonmethane hydrocarbons in the northeastern United States: Measured seasonal variations from 1992–1996 and 1999–2001
Authors: Lee Ben H. , Munger J. William , Wofsy Steven C. , Goldstein Allen H.
Published: October 2006

Harvard Forest, a rural site located in central Massachusetts downwind of major urban‐industrial centers, provides an excellent location to observe a typical regional mixture of anthropogenic trace gases. Air that arrives at Harvard Forest from the southwest is affected by emissions from the U.S. east coast urban corridor and may have residual influence from emissions in the upper Ohio Valley and Great Lakes region farther to the west. Because of its relatively long distance from large individual emission sources, pollution plumes reaching the site are a homogenized mixture of regional anthropogenic emissions. Concentrations of C2‐C6hydrocarbons along with CO and NOywere measured nearly continuously from August 1992 through July 1996 and from June 1999 through November 2001. By correlating observed concentrations to acetylene, which is almost solely produced during combustion, we are able to detect seasonal trends in relative emissions for this series of trace gases. Seasonal changes inn‐butane andi‐butane emissions may largely be influenced by different gasoline formulations in late spring and summer. Shifts in evaporation rates due to the annual temperature cycle could induce a seasonal pattern forn‐pentane,i‐pentane andn‐hexane emissions. Emissions of ethane and propane lack clear seasonality relative to acetylene emissions and also correlate less with acetylene than other gases, indicating that emissions of these two gases are strongly influenced by sources not associated with fuel combustion. Changes in the observed correlations of CO2and CO relative to acetylene are consistent with published changes in the estimated emissions of CO2and CO over the past decade, though variability in the observations makes it difficult to precisely quantify these changes.
Characterization of the atmospheric temperature and moisture conditions above Dome C (Antarctica) during austral summer and fall months
Authors: Tomasi Claudio , Petkov Boyan , Benedetti Elena , Vitale Vito , Pellegrini Andrea , Dargaud Guillaume , De Silvestri Lorenzo , Grigioni Paolo , Fossat Eric , Roth William L. , Valenziano Luca
Published: October 2006

Two sets of radiosounding measurements were taken at Dome C (Antarctica) in December 2003 and January 2003 and 2004, using RS80‐A, RS80‐H, and RS90 Vaisala radiosondes, and from March to May 2005, employing the RS92 model. They were examined following accurate correction procedures to remove the main relative humidity dry bias and the temperature and humidity lag errors. The results showed that a strong cooling usually characterizes the thermal conditions of the whole troposphere from December/January to April/May, with an average temperature decrease from 245 to 220 K at the ground, of around 10 K at upper tropospheric levels, and of more than 15 K in the lower stratosphere. The relative humidity data were found to be affected by dry bias of 5–10%, on average, for the RS80‐A and RS80‐H Humicap sensors and by smaller percentages for the other sensors. The mean monthly vertical profiles of absolute humidity were found to decrease sharply throughout the troposphere, especially within the first 3 km, and to diminish considerably passing from December/January to March/April/May, with average values of precipitable water decreasing from 0.75 to 0.28 mm, median values from 0.69 to 0.25 mm, and first and third quartiles from 0.60 to 0.22 mm and from 0.87 to 0.34 mm, respectively. The results demonstrate that Dome C (where a permanent scientific station has been open for winter operations since austral winter 2005) is a site of comparable quality to the South Pole for both validation of satellite radiance measurements and astronomic observations in the infrared, submillimetric, and millimetric wavelength range, performed with large telescopes that cannot be carried on satellites.
Sudan‐Sahel rainfall onset: Definition of an objective index, types of years, and experimental hindcasts
Authors: Fontaine Bernard , Louvet Samuel
Published: October 2006

Using rainfall estimates from the 5‐day version of CPC Merged Analysis of Precipitation (CMAP) and Global Precipitation Climatology Project data along with multiscale spatial key descriptors of atmospheric dynamics from National Center for Environmental Prediction/Department of Energy reanalysis 2 (NCEP/DOE), we first define a West African monsoon onset index to determine its successive dates of occurrence over the period 1979–2004 (28–29 June in mean with a standard deviation of 8.5 days). Then we focus on the three main types of time evolutions of that index at the moment of the monsoon onset in terms of precipitation, pressure, temperature, and winds at different levels to detect the most robust associated signals and select on the mid‐May, mid‐June period different sets of potential predictors for onset dates. Basically, late (early) onsets are preceded by more (less) rainfall southward to the equator by the end of May, then by a clear decrease (increase) of the normal northward cross‐equatorial gradient in mid‐June. Finally, we present experimental cross‐validated hindcasts of the dates of onset always based on four predictors using both reanalyzed atmospheric data and observed rainfall estimates. Accurate forecasting schemes are obtained, especially with CMAP rainfall (time tendencies and cross‐equatorial gradients) over the Gulf of Guinea. In this context the hindcasted series are highly significant when compared to observations (75% of explained common variance with the sole rainfall predictors) and can reach 82% of variance when a zonal wind descriptor of regional scale is added. Basically, a late (early) onset is preceded by more (less) rainfall southward to the equator by the end of May, then by a clear decrease (increase) of the normal northward cross‐equatorial gradient by mid‐June.
A Riccati model for Denmark Strait overflow variability
Authors: Käse R. H.
Published: October 2006

A controlled volume box model of the western basins of the Nordic Seas for water denser than 1027.8 kg m−3 is constructed, where accumulation in volume () is driven by net imbalances between prescribed net inflow from the northern, eastern and top boundaries (Qs) and hydraulically limited outflow through the Denmark Strait. The resulting Riccati equation is solved analytically for filling and flushing experiments with constant Qs and numerically for stochastic forcing Qs(t). For small perturbations to Qs with white noise spectrum, the overflow response is red noise with a time scale between 5 and 15 years depending on the mean interface height and area. For Qs proportional to the NAO index, the overflow is positively correlated with the NAO. A 140 years integration reveals variations in the overflow between 2.5 Sv in the 1970s and a maximum of 4 Sv in the 1990s. Hydraulic transport calculations from hydrographic data north of Iceland show good agreement with the model hindcast.
Testing the independence of partial thermoremanent magnetizations of single‐domain and multidomain grains: Implications for paleointensity determination
Authors: Yu Yongjae , Dunlop David J.
Published: October 2006

The Thellier method of paleointensity determination requires that partial thermoremanent magnetizations (pTRMs) be additive, mutually independent, and reciprocal in their thermal blocking and unblocking. We tested the independence law by thermally demagnetizing a sum of orthogonal pTRMs produced by replacing part of an original TRM(TC, T0, H) by pTRM(T, T0, H), with H rotated 90° between the TRM and the pTRM (TC, Curie temperature; T0, room temperature). The composite remanence simulates thermal remagnetization in nature. For single‐domain grains, thermal demagnetization resolved the orthogonal pTRMs cleanly. Two remagnetization temperatures were tried, T = 400°C and 550°C; the latter gave a better test because the two pTRMs were almost equal. Directions were recovered to within ∼5° for three of the four pTRMs, trajectories on vector diagrams intersected at exactly 400°C or 550°C, and the Arai plots were linear and yielded the correct field intensity for both pTRMs. However, multidomain magnetite violated the independence law. A remagnetization temperature T = 400°C produced almost equal pTRMs, but in thermal cleaning, because of overlap of their unblocking spectra they no longer appeared orthogonal. Each was displaced 13–15° toward the direction of the other as judged by quasi‐linear segments on a vector diagram. The angle between the fields that produced the pTRMs thus appeared to be ∼60°, not 90°. Arai plots for both pTRMs were strongly curved and yielded no usable paleointensity estimate. Phenomenological modeling correctly predicted the main results of the independence experiments.
Model analysis of influence of wave‐current interaction on current measurement of HF ocean surface radar for isolated eddy and upwelling
Authors: Nadai Akitsugu
Published: October 2006

The influence of wave‐current interaction on the current measurement of HF ocean surface radar (HFOSR) is analyzed by a simulation of the Doppler velocity spectra of the first‐order echo. The Doppler velocity spectra is a product of the spatial integration of the radial velocity weighted by the radar sensitivity and the normalized radar cross section (NRCS). As a result of the wave number change due to the wave‐current interaction and the extension of the wave packet due to the divergence of ocean currents, the NRCS distribution becomes nonuniform. The artificial component is produced around the center of the current phenomena in the simulated radial velocity field because the nonuniformity of the NRCS distribution distorts the spectral shape of the first‐order echo. The artificial component flows in the opposite direction of the propagation of the causal ocean waves. The intensity of the artificial component depends on the spatial scale ratio of the radar sensitivity distribution to the current phenomenon. In addition, the spatial averaging effect caused by the radar sensitivity distribution leads the antisymmetric component of the radial velocity difference, which weakens the intensity of the simulated current phenomena. The averaging of the two radial velocities extracted from the two first‐order echoes, corresponding to the approaching and receding causal ocean waves, is effective in reducing the artificial component in the measured radial current velocity by HFOSR, because the artificial components in the simulated radial velocities have almost the same spatial distributions with the opposite direction of flow.
Comparison of near‐infrared and thermal infrared cloud phase detections
Authors: Chylek Petr , Robinson S. , Dubey M. K. , King M. D. , Fu Q. , Clodius W. B.
Published: October 2006

We compare the results of the cloud thermodynamic phase detections that use (1) the ratio of the near‐infrared and visible bands or (2) the brightness temperature difference of two thermal infrared bands. We find that the brightness temperature difference algorithm using the Moderate Resolution Imaging Spectroradiometer (MODIS) bands is generally consistent with the expectations based on the retrieval of the cloud top radiative temperature. On the other hand, the band ratio method, which uses near‐infrared and visible bands, assigns considerably more ice phase compared to the brightness temperature difference method and leads to discrepancies with the expectations based on the cloud top radiative temperature. When the cloud phase algorithm, developed originally for the Department of Energy Multispectral Thermal Imager research satellite, is applied to the MODIS imagery, the cloud phase assignments are close to the brightness temperature difference results and are in better agreement with the expectations based on the cloud top radiative temperature.
Forecast, measurement, and modeling of an unprecedented polar ozone filament event over Mauna Loa Observatory, Hawaii
Authors: Tripathi Om Prakash , Leblanc Thierry , McDermid I. Stuart , Lefèvre Frank , Marchand Marion , Hauchecorne Alain
Published: October 2006

In mid‐March 2005 the northern lower stratospheric polar vortex experienced a severe stretching episode, bringing a large polar filament far south of Alaska toward Hawaii. This meridional intrusion of rare extent, coinciding with the polar vortex final warming and breakdown, was followed by a zonal stretching in the wake of the easterly propagating subtropical main flow. This caused polar air to remain over Hawaii for several days before diluting into the subtropics. After being successfully forecasted to pass over Hawaii by the high‐resolution potential vorticity advection model Modèle Isentrope du transport Méso‐échelle de l'Ozone Stratosphérique par Advection (MIMOSA), the filament was observed on isentropic surfaces between 415 K and 455 K (17–20 km) by the Jet Propulsion Laboratory stratospheric ozone lidar measurements at Mauna Loa Observatory, Hawaii, between 16 and 19 March 2005. It was materialized as a thin layer of enhanced ozone peaking at 1.6 ppmv in a region where the climatological values usually average 1.0 ppmv. These values were compared to those obtained by the three‐dimensional Chemistry‐Transport Model MIMOSA‐CHIM. Agreement between lidar and model was excellent, particularly in the similar appearance of the ozone peak near 435 K (18.5 km) on 16 March, and the persistence of this layer at higher isentropic levels for the following three days. Passive ozone, also modeled by MIMOSA‐CHIM, was at about 3–4 ppmv inside the filament while above Hawaii. A detailed history of the modeled chemistry inside the filament suggests that the air mass was still polar ozone–depleted when passing over Hawaii. The filament quickly separated from the main vortex after its Hawaiian overpass. It never reconnected and, in less than 10 days, dispersed entirely in the subtropics.
Design of a tangential phase contrast imaging diagnostic for the TCV tokamak
Authors: Marinoni A. , Coda S. , Chavan R. , Pochon G.
Published: October 2006

A core density fluctuation imaging diagnostic is being developed for the TCV tokamak, employing a 7cm wide CO2 laser beam transmitted through the plasma in a near-toroidal direction. The proposed system employs the phase contrast method and can resolve wavelengths ranging from 7 down to 0.1cm, with a minimum measurable line-averaged density of 3×1015m3∕MHz1∕2. The broad range of microinstabilities that can be at play in the strongly electron-cyclotron-resonance heated TCV plasmas, from ion to electron spatial scale lengths, widely known as ion-temperature-gradient, trapped-electron-mode, and electron-temperature-gradient modes, would thus be accessible. The use of an imaging technique overcomes the difficulties faced by traditional scattering diagnostics in investigating highly inhomogeneous regions, such as internal transport barriers. Wavelengths and correlation properties can be recovered from the spatial mapping. The tangential configuration, combined with appropriate spatial filtering techniques, provides an excellent spatial resolution, of the order of 1% of the minor radius. In view of the extreme plasma shaping and positioning flexibility of the TCV tokamak, the beam positioning will also be flexible, with translatable mirrors enabling measurements close to the magnetic axis in some configurations.
Crystallization on heating and complex phase behavior of α-cyclodextrin solutions
Authors: Plazanet M. , Dean M. , Merlini M. , Hüller A. , Emerich H. , Meneghini C. , Johnson M. R. , Trommsdorff H. P.
Published: October 2006

Solutions composed of α-cyclodextrin (α-CD), water, and various methylpyridines, in particular, 4-methylpyridine (4MP), undergo reversible liquid-solid transitions upon heating, the crystalline solid phases undergoing further phase transformations at higher temperatures. This unusual behavior has been characterized by an ensemble of measurements, including solubility, differential scanning calorimetry, quasielastic neutron scattering, as well as x-ray powder diffraction. For the α-CD/4MP system five crystalline phases have been identified. The unit cell parameters and corresponding changes with temperature indicate a scenario for the crystallization process. A simple model is proposed that mimics the observed disorder-order transition.
Frequency measurements of the gyrotrons used for collective Thomson scattering diagnostics at TEXTOR and ASDEX Upgrade
Authors: Woskov P. , Bindslev H. , Leipold F. , Meo F. , Nielsen S. K. , Tsakadze E. L. , Korsholm S. B. , Scholten J. , Tito C. , Westerhof E. , Oosterbeek J. W. , Leuterer F. , Monaco F. , Muenich M. , Wagner D.
Published: October 2006

High resolution frequency measurements of the 110GHz gyrotron at TEXTOR and the 105GHz mode of the two-frequency gyrotron (Odissey-1) at ASDEX Upgrade (AUG) have been made in support of fast ion collective Thomson scattering diagnostics. Measurements were done by harmonic heterodyne methods using both fast Fourier transform spectroscopy with digital oscilloscopes and fast scanning spectrum analyzers. Accurate frequencies were obtained with a frequency counter. At TEXTOR, at 180kW forward power the starting frequency was 109.970±0.005GHz and chirped down as much as 27MHz depending on the duty factor. At AUG, at 500kW forward power the frequency started at 104.786GHz and chirped down 104MHz, with 90% of the chirp occurring in the first 100ms. Plasma perturbation of the TEXTOR gyrotron was observed when both ion cyclotron resonance heating antennas and neutral beam injection were operating, producing modulation at 29 and 58MHz in the gyrotron output. Each gyrotron was observed to have an instrumental measurement limited linewidth of 120kHz full width at half maximum.
Microwave imaging reflectometry in LHD
Authors: Yamaguchi S. , Nagayama Y. , Pavlichenko R. , Inagaki S. , Kogi Y. , Mase A.
Published: October 2006

A multichannel reflectometry with an imaging optical system is under development for the measurement of the electron density fluctuations in the Large Helical Device (LHD). The right-hand cutoff layer is utilized as a reflection surface. The angle of an ellipsoidal mirror installed inside the vacuum chamber is remotely adjustable with the ultrasonic motor in order to optimize the illumination angle for the wider range of the plasma parameters. An oscillation due to density fluctuation was observed using the microwave imaging reflectometry for the first time in LHD plasma experiment.
High-energy point-projection radiography of a driven, shielded Hohlraum
Authors: Keiter Paul A. , Workman Jonathan
Published: October 2006

Point projection backlighting is a high magnification, high resolution x-ray backlighting configuration that provides detailed images of large objects at a reduced energy budget compared to area backlighting. However, point projection backlighting has the drawback that the camera aperture is large and open to more sources of noise. This issue has made it difficult to image driven targets without shielding. We present 9keV x-ray images of the rear end of a driven Hohlraum that employs shielding. We also present data of a 10.3keV x-ray image of an undriven Hohlraum.