bluuebunny/crossref_metadata_2025 huggingface dataset:
An Extension of the Structural Change Model to International Economic Relations
Authors: Araujo Ricardo Azevedo , Teixeira Joanílio Rodolpho
Published: October 2003

In this paper Pasinetti's model of structural economic dynamics (1981) is extended to consider international economic relations. Conditions for full employment, full expenditure of income and equilibrium of the trade balance are established for an open economy that requires capital goods to produce final commodities. Analytical results concerning the benefits from free trade and international learning are formally studied. In addition, static and dynamic aspects of the ‘principle of comparative cost advantage’ are analysed considering the determinants of the specialization level.
Molecular phylogeny of Ustilago and Sporisorium species (Basidiomycota, Ustilaginales) based on internal transcribed spacer (ITS) sequences
Authors: Stoll Matthias , Piepenbring Meike , Begerow Dominik , Oberwinkler Franz
Published: October 2003

DNA sequence data from the internal transcribed spacer (ITS) region of the nuclear rDNA genes were used to determine a phylogenetic relationship between the graminicolous smut genera Ustilago and Sporisorium (Ustilaginales). Fifty-three members of both genera were analysed together with three related outgroup genera. Neighbor-joining and Bayesian inferences of phylogeny indicate the monophyly of a bipartite genus Sporisorium and the monophyly of a core Ustilago clade. Both methods confirm the recently published nomenclatural change of the cane smut Ustilago scitaminea to Sporisorium scitamineum and indicate a putative connection between Ustilago maydis and Sporisorium. Overall, the three clades resolved in our analyses are only weakly supported by morphological characters. Still, their preferences to parasitize certain subfamilies of Poaceae could be used to corroborate our results: all members of both Sporisorium groups occur exclusively on the grass subfamily Panicoideae. The core Ustilago group mainly infects the subfamilies Pooideae or Chloridoideae.Key words: basidiomycete systematics, ITS, molecular phylogeny, Bayesian analysis, Ustilaginomycetes, smut fungi.
Paleoenvironmental analysis of the late Neoproterozoic Mistaken Point and Trepassey formations, southeastern Newfoundland
Authors: Wood Donald A , Dalrymple Robert W , Narbonne Guy M , Gehling James G , Clapham Matthew E
Published: October 2003

The Mistaken Point and Trepassey formations (Conception and St. John's groups, respectively) comprise a terminal Neoproterozoic, deep-marine succession of fine-grained turbidites and volcanogenic deposits that are part of the Avalonian Terrane. Debris-flow beds, slumped units, the low dispersion of turbidity-current paleoflow directions, and the absence of wave-generated structures together indicate that the sediment was deposited on a deep-water, southeast- facing slope. Channels were not present in the study area. The upward increase in the abundance of slump structures suggests that these units represent toe-of-slope and mid-slope environments, respectively. These units prograded over basin-floor deposits of the Drook and Briscal formations, which have (axial) paleocurrent directions that are orthogonal to the inferred downslope flow that characterized the overlying deposits. Within the Mistaken Point and Trepassey formations, a diverse assemblage of soft-bodied, non-phototrophic Ediacaran organisms is preserved beneath volcanic ash layers on more than one hundred surfaces. Individual fossiliferous surfaces can be correlated up to several kilometres. The felling orientations of frondose fossils indicate that contour currents, as well as up- and downslope currents of tidal and (or) wind-forced origin, influenced the sea floor in the intervals between event beds when the organisms lived. The contour currents may have been responsible for sustaining the organisms in this deep-water setting. The current-produced inclination of the frondose organisms at the time of ash deposition allowed their preservation by preventing the accumulation of ash beneath them.
Cycles and trends in the recent eruptive behaviour of Mount Etna (Italy)
Authors: Behncke Boris , Neri Marco
Published: October 2003

Mount Etna is among the few volcanoes on Earth that erupt nearly continuously, but its activity (in terms of output rate and flank eruption frequency) undergoes significant fluctuations in time. Such fluctuations do not occur randomly, but represent various stages of cycles on a scale of decades and centuries. Recurrent patterns are particularly evident since 1865, with four complete cycles and a fifth one initiated in 1993. Each cycle consists of three phases, beginning with low-level activity followed by nearly continuous summit activity and culminating with a series of flank eruptions, the last commonly being the most voluminous. A distinct increase in the output rate of Etna, along with more frequent and voluminous summit and flank eruptions since 1950, may be interpreted as part of a longer cycle that began after a large eruption in 1669 and has not yet reached its culminating phase. If that trend continues, the activity of Etna might become similar to that of the 17th century, when flank eruptions were more voluminous than they have been since; however, it is difficult to assess when this will take place.
Little Ice Age glacial activity in the Mt. Waddington area, British Columbia Coast Mountains, Canada
Authors: Larocque S J , Smith D J
Published: October 2003

The establishment of fourteen Little Ice Age (LIA) glacier chronologies in the Mt. Waddington area led to the development of an extended history of glacial activity in this portion of the southern British Columbia Coast Mountains, Canada. The glaciers were located within four different mountain ranges, and were of varying size and aspect. Dendrochronological and lichenometric techniques were used to provide relative age estimates of moraines formed as glacier termini retreated from advanced positions. Evidence for pre-LIA glacial events is best preserved at Tiedemann Glacier, where the oldest glacial advances date to A.D. 620 and 925933. Soil-covered and well-vegetated moraines built at Cathedral, Pagoda, and Siva glaciers date to between A.D. 1203 and 1226. Following this event, moraines constructed at Ragnarok, Siva, and Cathedral glaciers in the mid-14th century suggest glaciers in the region underwent a period of downwasting and retreat before readvancing. The majority of moraines recorded in the Mt. Waddington area describe late-LIA glacial events shown to have constructed moraines that date to A.D. 14431458, 15061524, 15621575, 15971621, 16571660, 17671784, 18211837, 18711900, 19151928, and 19421946. Over the last 500 years, these moraine-building episodes were shown to occur on average every 65 years and suggest there has been prolonged synchronicity in the glaciological response to persistent climate-forcing mechanisms. Nevertheless, our analysis suggests that local factors, such as aspect and size, play an important role in individual glacial response. Notably, ice termini of medium-size glaciers facing eastwards showed a quicker response to climatically induced mass balance changes.
Mapping aboveground tree biomass at the stand level from inventory information: test cases in Newfoundland and Quebec
Authors: Fournier R A , Luther J E , Guindon L , Lambert M -C , Piercey D , Hall R J , Wulder M A
Published: October 2003

A method of estimating and mapping aboveground tree biomass (AGTB) was developed using provincially available forest inventory databases. More specifically, AGTB conversion tables were devised to estimate biomass for stand attributes that are commonly mapped in provincial inventories over the Canadian landscape, i.e., species composition, projected crown density, and dominant tree height. AGTB is first estimated at the tree level using allometric relationships and measured stem distributions that are subsequently summed to estimate plot-level biomass. AGTB conversion tables are then computed from regression models that relate the plot-level biomass values to stand attributes. AGTB can then be mapped over the landscape by assigning the plot-level biomass values to the mapped stands. The method was developed using two provinces, Newfoundland and Labrador (N.L.) and Quebec, as test cases to assess the adaptation required between different management units. Models used to develop conversion tables from the test areas provided estimates of biomass with R2 ranging from 0.22 to 0.35 and from 0.31 to 0.64 and root mean square errors of 38 to 47 t/ha and 21 to 41 t/ha for N.L. and Quebec, respectively, based on an independent validation data set not used in the development of the models. Mapping errors and potential improvements to the models are discussed. To extend the methods developed in this study to a national map of forest AGTB will require significant adjustments to account for differences in regional inventory specifications. While the method for AGTB mapping can fulfil an important monitoring requirement in forestry, applying it to all provinces, as well as including alternate data sources for areas where inventories do not exist, such as satellite remotely sensed images, requires further research, some of which is currently in progress.
Summer temperature in northeastern Siberia since 1642 reconstructed from tracheid dimensions and cell numbers of Larix cajanderi
Authors: Panyushkina Irina P , Hughes Malcolm K , Vaganov Eugene A , Munro Martin AR
Published: October 2003

We reconstructed air temperature for two periods in the growth season from cell dimension and cell number variability in cross-dated tree rings of Larix cajanderi Mayr. from northeastern Siberia. Thirteen tree-ring chronologies based on cell size, cell wall thickness, and cell number were developed for AD 16421993. No clear evidence was found of an age-related trend in cell dimensions in the sampled materials, but cell numbers were correlated with cambial age. The chronologies contain strong temperature signals associated with the timing of xylem growth. We obtained reliable reconstructions of mean June temperature from the total cell number and JulySeptember temperature from the cell wall thickness of latewood. June temperature and JulySeptember temperature covaried for most of the period from AD 1642 to AD 1978. After that time, June temperature became cooler relative to JulySeptember temperature. This difference caused disproportional changes in earlywood tracheids because of the late start of growth and cool conditions in June followed by warming during the rest of the season. The identification of this unusual recent change has shown that intraseasonal resolution may be achieved by cell dimension and cell number chronologies.
Initial responses of phosphorus biogeochemistry to calcium addition in a northern hardwood forest ecosystem
Authors: Fiorentino Isabella , Fahey Timothy J , Groffman Peter M , Driscoll Charles T , Eagar Christopher , Siccama Thomas G
Published: October 2003

We measured changes in P pools and cycling 1 year after a Ca fertilization treatment at the Hubbard Brook Experimental Forest in central New Hampshire. We hypothesized that by increasing soil pH and available Ca, the treatment would change the amount of readily available P in the forest floor and the biogeochemical cycling of P in the forest ecosystem. One year after the Ca addition, significant increases occurred in soil pH (one pH unit), resin-sorbed P (2- to over 10-fold), and the microbial respiratory quotient (27%) in the Oe horizon of the treated watershed compared with a reference watershed. Additionally, we observed significant increases in foliar P concentrations (20133% across six species) and in P retranslocation in the treated watershed between pre- and post-Ca-addition years (p < 0.05). Foliar P was strongly correlated (r = 0.74) with resin-sorbed P. Microbial biomass P, microbial C to P ratios, and available organic and inorganic P fractions were lower in the Oe horizon of the treatment watershed than in the reference watershed, but no differences were observed in soil solution or fine root P concentration. Apparently, by changing soil pH, Ca addition increased rates of P cycling in forest floor horizons at Hubbard Brook Experimental Forest.
Compensating for missing plot observations in forest inventory estimation
Authors: McRoberts Ronald E
Published: October 2003

The Enhanced Forest Inventory and Analysis program of the U.S. Forest Service has established a nationwide array of permanent field plots, each representing approximately 2400 ha. Each plot has been assigned to one of five interpenetrating, nonoverlapping panels, with one panel selected for measurement on a rotating basis each year. As with most large surveys, observations for some plots are not obtained. Several techniques for dealing with missing observations were compared with respect to the bias and precision of stratified estimates of mean volume per unit area using data from the State of Indiana in the north-central region of the United States for illustrative purposes. For the proportion of missing plots ranging from 1% to 10%, acceptable results were obtained for techniques that both ignored and replaced missing plot observations, but only when the techniques accounted for differences between plots in private and public ownerships.
Gap characteristics in relation to forest structure and implications for southern beech forest dynamics
Authors: Cuevas Jaime G
Published: October 2003

Gap characteristics, as well as forest structure, were investigated in Nothofagus pumilio (Poepp. et Endl.) Krasser stands on two slopes in Tierra del Fuego to test the following hypotheses: (i) there exists an altitudinal decline in tree height and stem diameter, (ii) this should result in gaps of decreasing size and abundance towards the upper forest, and (iii) this, in turn, should result in a longer suppressed growth of seedlings near the treeline (that is, an older seedling bank). Mean tree height on both slopes decreased significantly with increasing altitude from 21 to 11 m and from 13 to 8 m. Mean stem diameter declined with increasing altitude from 50 to 28 cm and from 19 to 16 cm, but this trend was only significant on one slope analyzed. Gap frequency declined with increased elevation from 33 to only 3 in 2-km transects. Mean gap size also decreased significantly with increased elevation from 91 to 11 m2. Mean seedling age varied with altitude, but the expected relationship was significant only when gap frequency was controlled. The best-fit model indicates a negative correlation between altitude and tree height and stem diameter, which are positively correlated and act indirectly on gap frequency via gap size. Although restrictions on seedling growth caused by small and infrequent gaps do not seem to be stronger at upper forest elevations, they may produce a bottleneck in the life cycle of the species in the long term. This phenomenon could be overcome either through faster seedling growth and higher survival at the treeline or through an episodic regeneration, as other research has documented previously.
Seed rain, safe sites, competing vegetation, and soil resources spatially structure white pine regeneration and recruitment
Authors: Dovčiak Martin , Reich Peter B , Frelich Lee E
Published: October 2003

We tested the effects of seed rain, safe sites, soil depth, overstory, and shrub layer on the establishment and recruitment of white pine (Pinus strobus L.) in aspen mixedwoods of the western Great Lakes region, U.S.A. Germin ant and seedling densities were positively related to seed rain and safe site characteristics that indicate moist conditions: high overstory basal area, decaying wood, and moss cover. Germinant and seedling densities were highest under dense overstory (>16 m2/ha) and were unrelated to shrub cover. Sapling recruitment was greatest under low overstory density (<16 m2/ha) and low shrub cover (<55%). On shallow soil (~14 cm), germinants and seedlings commonly occurred on soil depths <5 cm, but large saplings almost always occurred on soil depths >5 cm. On deeper soil (~21 cm), overstory white pines occupied the shallowest soils (~18 cm) of all major overstory species, indicating that competition may cause white pine recruitment into the canopy to be lower on deeper soils. White pine populations in the study were initially spatially structured by seed rain and safe sites but sapling growth and recruitment was structured by overstory density, shrub cover, and soil depth.
Best linear unbiased prediction of clonal breeding values and genetic values from full-sib mating designs
Authors: Xiang Bin , Li Bailian
Published: October 2003

Full-sib progeny tests with clonal replicates may provide better breeding value estimates and the greatest genetic gain in a tree improvement program. Clonal breeding values (CBV) that combine the family and within-family breeding values due to additive genetic effects can maximize the genetic gain for advanced generation breeding. Clonal genetic values (CGV) that further incorporate full-sib family specific combining ability due to nonadditive genetic effect can maximize gain for a deployment program with clonal propagation techniques. The best linear unbiased prediction (BLUP) is the best statistical method for estimating both CBV and CGV because of its desirable statistical properties compared with the heritability-based gain calculation. A BLUP method for determining both the CBV and CGV for full-sib clonal progeny tests was proposed in this paper. The formulas for CBV and CGV were derived using general BLUP methodology, and formulas were derived for the calculations of their standard errors. An analytical method by using a standard statistical package (SAS PROC MIXED) was presented for CBV and CGV calculations from any full-sib mating designs.
Impact of feeding damage by the porcupine on western hemlock  Sitka spruce forests of north-coastal British Columbia: 15-year results
Authors: Woods Alex J , Zeglen Stefan
Published: October 2003

American porcupine (Erithizon dorsatum L.) feed on the cambial tissues of several tree species. This study assessed feeding by porcupine over a 15-year period on midrotation age western hemlock (Tsuga heterophylla (Raf.) Sarg.) dominated stands on the north coast of British Columbia, Canada. Although four coniferous hosts were available, hemlock was, by far, the most preferred and most seriously impacted. Of 398 hemlock studied, 260 were wounded by porcupine feeding and 86 died by 2000. Porcupine attacked two-thirds of the dead trees, over 82% of which were dominant or codominant, while almost all unattacked dead trees were intermediate or suppressed. This loss resulted in a 14.6% reduction in the proportion of volume per hectare represented by hemlock and an increase in the representation by other species, all of which suffered little or no feeding damage. Results indicate that the final merchantable volume of hemlock expected at rotation age will be lower than projected and will consist mainly of damaged trees of poor form and quality due to decay fungi, such as Stereum sanguinolentum (A. & S. ex Fr.), entering through feeding wounds. Porcupine activity has led to a shift in species composition and volume from a condition where a single species, western hemlock, dominates to a mixed forest consisting of amabilis fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes), Sitka spruce (Picea sitchensis (Bong.) Carrière), and western hemlock.
Spatial variability of aboveground net primary production for a forested landscape in northern Wisconsin
Authors: Burrows S N , Gower S T , Norman J M , Diak G , Mackay D S , Ahl D E , Clayton M K
Published: October 2003

Quantifying forest net primary production (NPP) is critical to understanding the global carbon cycle because forests are responsible for a large portion of the total terrestrial NPP. The objectives of this study were to measure above ground NPP (NPPA) for a land surface in northern Wisconsin, examine the spatial patterns of NPPA and its components, and correlate NPPA with vegetation cover types and leaf area index. Mean NPPA for aspen, hardwoods, mixed forest, upland conifers, nonforested wetlands, and forested wetlands was 7.8, 7.2, 5.7, 4.9, 5.0, and 4.5 t dry mass·ha1·year1, respectively. There were significant (p = 0.01) spatial patterns in wood, foliage, and understory NPP components and NPPA (p = 0.03) when the vegetation cover type was included in the model. The spatial range estimates for the three NPP components and NPPA differed significantly from each other, suggesting that different factors are influencing the components of NPP. NPPA was significantly correlated with leaf area index (p = 0.01) for the major vegetation cover types. The mean NPPA for the 3 km × 2 km site was 5.8 t dry mass·ha1·year1.
Bivariate distribution functions for predicting twig leaf area within hybrid spruce crowns
Authors: Temesgen H , LeMay Valerie M , Cameron Ian R
Published: October 2003

The vertical and horizontal distribution of leaf area per centimetre of twig (APCM) for hybrid spruce (Picea engelmannii Parry ex Engelm. × Picea glauca (Moench) Voss × Picea sitchensis (Bong.) Carrière) tree crowns was modelled using bivariate Weibull and beta distribution functions. Horizontal position was represented by relative position on the first-order branch. Vertical position was based on branch position from the tree apex relative to tree height, since the base of the live crown is often difficult to locate. Sample APCM measures were obtained using systematic sampling of 12 tree crowns taken from stands at three developmental stages (20, 60, and 140 years of age). For comparison, univariate Weibull and beta distribution functions using only vertical distribution were also fitted. Generally, APCM decreased from the tree apex downward and from the branch tips toward the stem, although variation in the values was quite high. Trees from the middle stand age (60 years) had the highest average APCM values, followed by the smallest, youngest trees (stand age 20), and the lowest values were found for the largest trees in the oldest stand (140 years). As anticipated, the bivariate Weibull and beta distribution functions resulted in more precise representations of APCM within tree crowns than the univariate Weibull and beta distribution functions, although the improvements were minimal. Results were generally poorer for trees from the oldest stand. These functions could be used to evaluate other variables distributed over the tree crown, such as specific leaf area. The resulting models from this study were used to reconstruct the entire crown of every sample tree for conducting sampling simulations.
An algebraic framework of weighted directed graphs
Authors: Leroux Philippe
Published: October 2003

We show that an algebraic formulation of weighted directed graphs
leads to introducing a k‐vector space equipped with two
coproducts Δ and verifying the so‐called
coassociativity breaking equation . Such a space is
called an L‐coalgebra. Explicit examples of such
spaces are constructed and links between graph theory and
coassociative coalgebras are given.
Nested derivatives: a simple method for computing series expansions of inverse functions
Authors: Dominici Diego
Published: October 2003

We give an algorithm to compute the series expansion for the
inverse of a given function. The algorithm is extremely easy to
implement and gives the first N terms of the series. We show
several examples of its application in calculating the inverses
of some special functions.
Soviet Society, Public Attitudes, and the Perils of Gorbachev's Reforms: The Social Context of the End of the USSR
Authors: Connor Walter D.
Published: October 2003

Soviet society underwent profound changes during the seven-and-a-half decades of Soviet rule. By the late 1970s and 1980s, adverse economic and demographic trends had led to widespread public cynicism, especially among younger people. Mikhail Gorbachev was aware of the discontent within Soviet society when he came to office in 1985, and he pursued a reform program that was intended to remedy the country's ills and rejuvenate the society. In the end he failed. Although Soviet society did not “revolt” en masse against Gorbachev's reforms and the hardships that ensued, the crucial thing by 1991 was that the society as a whole no longer had much of a stake in the survival of the USSR—a stake that might have induced people to mobilize in favor of preserving a union.
Switching Therapy in Health Economics Trials: Confronting the Confusion
Authors: Torrance George W. , Drummond Michael F. , Walker Valery
Published: October 2003

Should patients in a randomized, pragmatic health economics trial be allowed to switch therapy in mid-trial to that pro- vided in the other arm? Specifically, should patients in the treatment arm (T) be allowed to switch to the therapy of the comparator arm (C) if they need a change of therapy—that is, should TC switches be allowed? Also, should patients in the comparator arm be allowed to switch to the therapy of the treatment arm if they need changes of therapy—should CT switches be allowed? This is a nontrivial issue in study design that has been debated in the clinical trials literature and is currently being handled inconsistently in the health economics literature. In this article, the authors argue that TC switches should always be allowed and that CT switches should be allowed or not depending on the economic question. They further argue that the most common economic question is one that would lead to CT switches not being al- lowed.
Preference-Based Measurement of Health-Related Quality of Life (HRQL) in Children with Chronic Musculoskeletal Disorders (MSKDs)
Authors: Brunner H. I. , Maker D. , Grundland B. , Young N. L. , Blanchette V. , Stain A-M. , Feldman B. M.
Published: October 2003

Background. Health-related quality of life can be measured by patients' health preferences (utilities or values). No method for measuring health state preferences has been standardized for children with arthritis or other musculoskeletal disorders (MSKDs). Such a method is needed for economic evaluations of current and new pediatric treatments. Objectives . 1) To assess the feasibility of utility measurements in children with MSKDs, 2) to test the validity of the Health Utility Index (HUI) for these children, 3) to assess whether rating scale values can be mathematically converted into meaningful standard gamble (SG) utilities, and 4) to study whether parents can act as proxies for their children with respect to health state preferences. Methods. Eighty parents of children with MSKDs were consecutively sampled. Their children, if 8 years of age or older (n = 55), were studied concurrently. Utilities of current health states were obtained by using the SG and the HUI in random order. In addition, health state preferences were assessed using categorical and analog rating scales. Traditional nonutility measures of health status (the Childhood Health Assessment Questionnaire [CHAQ] and the Activities Scale for Kids [ASK]) were also completed. Intraclass correlation coefficients (ICCs) were calculated to assess concordance between the different utility measures and also between the ratings of the parents and their children. Results. Children 8 years of age or older were able to express the strength of their health state preferences using the HUI and rating scales. Children older than 10 years of age were able to use the SG method. The health state utilities of the parents were higher than those of their children. The utilities varied widely depending on the elicitation method. The expected high agreement between the SG and the HUI was not found (ICC = 0.028 for parents, ICC = 0.016 for patients). Unlike the SG, the global utilities derived from the HUI agreed better with preferences derived from rating scales (ICC = 0.23-0.25) and correlated with traditional health status measures (with CHAQ, r = -0.56; with ASK, r = 0.46) both for parents and children. It was not possible to mathematically convert rating scale preferences into SG utilities. The SG utilities were unrelated to results from the rating scales, the CHAQ, and the ASK. Especially for parents, the SG utilities were very high, even when ratings of the other measures indicated poor health. Conclusions. Although it is possible to measure health utilities for children with MSKDs, the results are highly method dependent. The properties of the HUI in this population are more like those of the traditional health status measures rather than those of the SG. Preferences derived from rating scales, although easily performed, cannot readily be converted into SG utilities. Parents' ratings for their children are impaired by risk aversion.
Supplementarity and Surplus: Moving between the Dimensions of Otherness
Authors: Gillespie Alex T.
Published: October 2003

I start by attempting to clarify the ways in which Coelho and Figueiredo (2003) use the logic of supplementarity to conceptualize the discourses on intersubjectivity in terms of four dimensions of otherness. A new domain of application is proposed and the limits of the approach are pointed to. In the second section I critically examine the extent to which these four dimensions, and the movements of supplementarity between them, adequately capture the theories of intersubjectivity. The use of these dimensions seems, on the one hand, to obfuscate several interesting contradictions between the theoretical approaches within the dimensions, and, on the other hand, to artificially partition the theoretical traditions between the four dimensions. In the final section, Mead's account of intersubjectivity, and the constitution of subjectivity, is presented, and developed, as operating in the spaces between the proposed dimensions of otherness.
Orientation to the Setting: Discursively Accomplished Intersubjectivity
Authors: Murakami Kyoko
Published: October 2003

This article concerns intersubjective understanding; what it is to establish a shared understanding of the conversational activity in research interviews. This discussion was inspired by interpersonal subjectivity (Mead, 1910/1978) and constitution of otherness, one of the four matrices of intersubjectivity proposed by Coelho and Figueiredo (2003). In drawing attention to the interview as an intriguing and instructive realm of inquiry for social scientists, this article assumes two objectives: (1) outlining the concept of positioning as undergirding Coelho and Figueiredeo's third element of intersubjectivity—interpersonal intersubjectivity; and (2) suggesting how this might be studied using the discursive psychological and social constructionist approach. A specific task involved for this argument is a discourse analysis of an extract taken from interviews with British World War II veterans regarding their reconciliation experiences. I will argue that intersubjectivity is interactionally accomplished as an emergent feature of the discursive practices of remembering and reconciliation.
Unidentified Interference in DOAS Measurements of Ozone
Authors: Reisinger Andy R.
Published: October 2003

A differential optical absorption spectroscopy (DOAS) system was designed and operated in Christchurch, New Zealand, during the winter of 1997. We report the detection of an unidentified absorber in the 279 to 289 nm spectral region, which is used by many commercial DOAS systems for the measurement of atmospheric ozone on short absorption paths. Tests were performed to ensure that this absorber is not an artifact of the analysis procedure. The presence of the unidentified absorber can have serious consequences on ozone concentrations obtained with the DOAS technique when primary pollutant concentrations are high, while it is hardly noticeable under clean conditions. It is argued that either the absorber may be specific to New Zealand emissions, possibly due to the widespread use of wood fires for domestic heating, or that its influence is generally overlooked because interest in ambient ozone usually concentrates on summer smog conditions, where primary pollutant concentrations are generally lower than during winter.
Inductively Coupled Plasma/Microwave-Induced Plasma Tandem Source for Atomic Emission Spectroscopy
Authors: Pack Brian W. , Hieftje Gary M.
Published: October 2003

A microwave-induced plasma (MIP)/inductively coupled plasma (ICP) combination has been evaluated as an “atomization-excitation” tandem source (TS). The results indicate that some of the problems reported for similar sources in the past can be effectively reduced or eliminated. Desolvation of the analyte aerosol before its introduction into the tandem source improved detection limits only slightly. However, power modulation of the microwave plasma served to improve tandem-source performance in two ways. First, noise contributed by the ICP and the MIP was isolated one from the other. Since the modulation frequency was chosen to be far removed from the major noise frequencies observed from either of the two sources, more stable background signals were realized. Second, the intense background signal from the ICP could be discriminated against through use of a lock-in-amplifier tuned to the modulated MIP signal. Relative standard deviations of both the signal and the background were usually below 1% when the MIP power was modulated. Detection limits ranged from 0.53 ppb to 40 ppb for the elements examined, which represents an improvement of 5-to 40-fold over previously reported data for a similar tandem-source configuration. Disappointingly, these improved detection limits were still much worse than detection limits obtained by other investigators utilizing the ICP alone. Addition of a mixed gas did little to improve the performance of the tandem source; for barium and calcium ion lines, an increase of approximately three in signal-to-background ratios was observed upon the addition of hydrogen or helium.
Use of Laser Light Scatter Signals to Study the Effect of a Direct-Current Biased Mesh Screen in a Spray Chamber on Aerosols Generated for Use in Atomic Spectroscopy
Authors: Xu Qiang , Agnes George R.
Published: October 2003

A new method that relies on tertiary aerosol laser light scatter signals to alleviate the NaCl chemical matrix effect in inductively coupled plasma atomic emission spectroscopy (ICP-AES) is introduced. The method involves monitoring the laser light scatter signal from the entire tertiary aerosol with a line-shaped laser beam and the plasma off. In this work, the tertiary aerosol laser scatter signal was measured to increase nonlinearly with NaCl concentration. The source of the increased scatter signal is described as originating from Coulomb fission events that droplets with net charge experience while inside the spray chamber. Each droplet in the secondary aerosol that undergoes Coulomb fission introduces ∼ 20 progeny droplets into the aerosol stream. The introduction of progeny droplets to the aerosol stream measured by increased laser light scatter signals coincides with an increase in analyte emission, off-axis, at low viewing heights in an inductively coupled plasma, a characteristic of the easily ionized element chemical matrix effect. It is shown that a direct-current potential applied to a mesh screen positioned inside the spray chamber can coarsely control the transport of droplets with net charge through the spray chamber, by effecting their removal from the aerosol stream. With an appropriate voltage applied to the mesh, the laser scatter signal from the tertiary aerosol from a solution containing 100 mM NaCl can be made similar to the scatter signal from a solution that does not contain NaCl. Under the same conditions, calcium-ion lateral emission signal intensity contour maps in a plasma for the same two solutions become similar within the normal analytical zone in the plasma (2 mm wide, from 13 to 19 mm above the load coil).
Depth Profiling of Optical Absorption in Thin Films via the Mirage Effect and a New Inverse Scattering Theory. Part II: Experimental Reconstructions on Well-Characterized Materials
Authors: Fu S. W. , Power J. F.
Published: October 2003

Mirage effect spectrometry is experimentally evaluated in this work as a technique of optical depth profiling in thin films where no prior information is available about the sample properties. An apparatus suitable for performing quantitative measurements is described. High-precision experimental alignment procedures are introduced along with a new method for precise optical correction of the detector signal for experimental frequency response nonuniformities. Reconstructions were made of the heat source density and absorption coefficient depth profile in materials with known depth dependence. These included samples approximating weighted delta function arrays, and depth-continuous media known to obey Beer's law to a good approximation. The properties of these samples were examined independently by using a technique of depth-sensitive light microscopy. Mirage effect depth profiles reconstructed on samples containing discrete absorbers were effectively regularization limited, indicating that resolution is limited by random error in the data rather than experimental bias. Depth profiles obtained in continuously absorbing media show a good agreement with those obtained by reference methods.
Infrared Absorption and Ultraviolet-Circular Dichroism Spectral Studies of Thermally Induced Unfolding of Apomyoglobin
Authors: Mohney Brian K. , Petri Edward T. , Uvarova Victoria , Walker Gilbert C.
Published: October 2003

The static infrared absorption (IR) and circular dichroism (CD) spectra of the temperature-dependent conformational states of apomyoglobin in potassium phosphate and sodium acetate buffer solution at pH 5.3 in D2O are reported. The circular dichroism ellipticity at 222 nm reveals a loss of helical structure for both heat- and cold-denatured states. Cold denaturation leads to a molten globule state with an associated partial loss of helical structure identified at 1646 cm−1. Heat denaturation also exhibits an absorption loss at 1646 cm−1 but leads to the appearance of aggregation at 1680 and 1619 cm−1. There is semi-quantitative agreement of the ultraviolet circular dichroism and infrared estimates of protein helicity. The denaturation spectra give evidence that there are specific associations between acetate ions and the protein, but not between phosphate ions and the protein.
Detection of Riboflavin Based on Fluorescence Enhancement of Evanescent-Wave Excited β-Cyclodextrin Complex in Sol-Gel-Derived Porous Coatings
Authors: Wang Chi-Chang , Li Chia-I , Lin Yi-Hua , Chau Lai-Kwan
Published: October 2003

A sol-gel-derived film doped with β-cyclodextrin was used to construct a fiber-optic evanescent-wave fluorosensor. In this sensing configuration, the fluorescence emitted was detected from the side surface of the fiber, where the cladding at the distal end was removed. For detection of riboflavin, the fluorescence enhancement by the film coated at the distal end of an optical fiber is 10.6 times than that of an unmodified optical fiber. The enhancement is due to the accumulation of riboflavin in the sol-gel cladding and the more constrained microenvironment for riboflavin. The linear dynamic range of this sensor extends well over 2 orders of magnitude. Detection limit (signal-to-noise ratio = 3) is as low as 80 nM. The sensor is easy to operate, simple to construct, and requires a minimal number of optical components.
Ultraviolet Resonance Raman Spectroscopy of Bulk and Microscopic Human Colon Tissue
Authors: Boustany Nada N. , Manoharan Ramasamy , Dasari Ramachandra R. , Feld Michael S.
Published: October 2003

A sensitive ultraviolet resonance Raman (UVRR) system, which integrates bulk and microscopic capabilities, is described for use with human tissue. The system incorporates a quasi-continuous tunable laser excitation source in the range 200–300 nm, a liquid nitrogen-cooled charge-coupled device (CCD), a single grating spectrometer, dielectric longpass laser line rejection filters, and cooled specimen holders to minimize bio- and photo-degradation. The system was used on normal human colon tissue, and was compared to our previously used Nd:YAG-based system. Spectra with higher signal-to-noise ratio (S/N) than has previously been achieved, and with less than 5% photobleaching, are presented. The present system outperforms our previous system by improving the S/N in bulk normal colon spectra by a factor of greater than 10. We show for the first time UVRR spectra collected from the various microscopic regions of human colon in a thin section preparation, and the line shapes from the different microscopic morphological components are related to the bulk colon spectra. At 251 nm the epithelial cells and the lamina propria are the major contributors to the UVRR spectrum of bulk colon tissue. Our data suggest that combined bulk and microscopic UVRR spectroscopy of human tissue could provide a valuable tool for bioassay and histochemistry.
Near-Infrared Spectroscopy for in situ Cure Monitoring of Dimethacrylate-Based Networks
Authors: Rey L. , Galy J. , Sautereau H. , Lachenal G. , Henry D. , Vial J.
Published: October 2003

In this study, near-infrared transmission spectroscopy is investigated as an alternative technique for the real-time cure monitoring of thermosets systems. Two polymer systems based on dimethacrylate/styrene and dimethacrylate/divinylbenzene monomers were studied in order to check the influence of comonomer functionality. A new device utilizing ITO (indium-tin-oxide)-coated glass plates was developed to take into account the specificity of chain polymerization: oxygen inhibition, bulk polymerization, etc. Two absorption bands at 6166 and 6135 cm−1 suitable for in situ monitoring of methacrylate and vinyl double bonds were identified, and the molar absorption coefficient was determined. A quantitative analysis allows us to calculate the double-bond conversion during the polymerization in isothermal conditions between 60 and 80 °C.
Use of Near-Infrared Spectroscopy to Predict Potential Mushroom (Agaricus Bisporus) Yield of Phase II Compost
Authors: Sharma H. S. S. , Kilpatrick M.
Published: October 2003

The yield of fruiting bodies of Agaricus bisporus from compost is variable due to differences in available nutrients and cultural conditions during production. The objective of this study was to evaluate the use of near-infrared (NIR) reflectance spectroscopy for assessing potential compost productivity. Three compost comparative trials, carried out over the past six years under controlled experimental conditions, have generated a large sample set (48 × 3 = 144) with yield data. Visible and NIR reflectance measurements of the calibration samples were made over the range of 400–2498 nm. A partial least-squares (PLS) algorithm was used to generate the predictive models using the information in the spectrum. A model developed with the spectral region 1100–2498 nm could explain 87% of the variation in mushroom yields obtained from the three trials. The accuracy of the NIR yield model has been confirmed in a validation compost comparative trial. A combined calibration equation ( r2 = 0.93) using the spectral data (1100–2498 nm) from the four trials was developed with a standard error of cross-validation of 18.6 kg/tonne.
Freeze-Quench Resonance Raman and Electron Paramagnetic Resonance Spectroscopy for Studying Enzyme Kinetics: Application to Azide Binding to Myoglobin
Authors: Oellerich Silke , Bill Eckhard , Hildebrandt Peter
Published: October 2003

In the present work we have developed a reliable approach for probing the reaction dynamics of metalloproteins on the millisecond time scale. It is based on the combination of the freeze-quench method with resonance Raman (RR) and electron paramagnetic resonance (EPR) spectroscopy. The reactions are initiated in a mixing chamber and rapidly quenched at low temperature in liquid isopentane after variable delay times. The experimental device is designed in such a way that the same frozen samples can be subsequently studied by two analytical techniques, thereby providing complementary information about the active site structures of intermediate states of the enzyme. In particular, the present setup permits the measurement of high-quality RR spectra despite the interference by the Raman bands of isopentane. With the use of the azide binding reaction to myoglobin as a test case, it is found that RR spectroscopy allows a reliable determination of rate constants, whereas the quantitative analysis of the EPR spectra is associated with a relatively high and unavoidable uncertainty mainly due to irreproducible packing of the freeze-quenched samples.
Optimizing Resolution in Constant-Energy Synchronous Spectrofluorimetry
Authors: Eiroa A. Andrade , Huckins S. R. , Blanco E. Vázquez , Mahía P. López , Lorenzo S. Muniategui , Rodríquez D. Prada
Published: October 2003

Constant-energy synchronous luminescence (CESL) offers significant improvements in selectivity and sensitivity compared to the more conventional constant-wavelength synchronous luminescence (CWSL) technique. Despite this consideration, practical problems can be encountered that have not been reported in the literature. This paper offers an explanation of these technical issues—why they occur and how they can be avoided—and the method optimized to take full advantage of this powerful technique. Polycyclic aromatic hydrocarbons (PAHs) were selected for demonstrating all our conclusions, because of their carcinogenic activity; 16 of them appear in the EPA (Environmental Protection Agency) list as PAHs for which it is necessary to develop efficient methods for their precise and accurate quantification at low levels. The technique can be applied to other complex fluorescent mixtures.
Comparison of Four Digitizers for Time-Domain EPR
Authors: Eaton Gareth R. , Quine Richard W.
Published: October 2003

Pulsed, time-domain electron paramagnetic resonance (EPR) requires fast data collection. The ideal is for the data acquisition rate to be limited by the spin relaxation times, and not by the data collection hardware and software. Four devices with fast time response were compared in the collection of pulsed EPR data. The fastest data collection was achieved with a Bruker E587 SpecJet transient signal averager.
Calibration Procedure to Derive IRRAS Spectra from PM-IRRAS Spectra
Authors: Buffeteau T. , Desbat B. , Blaudez D. , Turlet J. M.
Published: October 2003

A calibration procedure is presented to relate Fourier transform infrared reflection-absorption spectroscopy (IRRAS) spectra obtained by polarization modulation (PM) and conventional techniques. This procedure concerns only PM-IRRAS measurements obtained with a lock-in amplifier. At the first stage, it consists in measuring two calibrated spectra, by adding a linear polarizer after the sample. The corresponding corrected PM-IRRAS spectra display band intensities close to those observed on IRRAS spectra (at about 6%), but the value of the baseline is lower. The calibration procedure can be performed at the second stage, by normalizing the corrected PM-IRRAS spectra of the sample and the bare substrate. In this case, the band intensities and the baseline of the normalized corrected PM-IRRAS and IRRAS spectra are similar.
Light-Induced Two-Dimensional FT-IR Spectroscopy of BacterioRhodopsin
Authors: Kosters P. G. H. , de Vries A. H. B. , Kooyman R. P. H.
Published: October 2003

Two-dimensional Fourier transform infrared (2D FT-IR) spectroscopy was applied to study the slower states of the membrane protein bacterioRhodopsin (bR) photocycle, with bR adsorbed on a ZnSe attenuated total reflectance (ATR) crystal. The M and the N states of the bR photocycle could be discriminated, and 2D spectra revealed an N state absorption band at 1536 cm−1 that is normally covered by the broader and bigger 1527 cm−1 M state absorption band. 2D FT-IR absorbance changes are presented in a more convenient way for analysis than in traditional 2D FT-IR spectroscopy by using 2D-phase spectra and phase/amplitude calculations.