bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical Analysis of Bioindicator Value of Epiphytic Lichens
Authors: Oksanen Jari , Läärä Esa , Zobel Kristjan 
Published: May 2007

AbstractGeneralized linear modelling was applied in analysing the bioindicator value of epiphytic lichens for air pollution around an industrial centre in the Siberian mountains using data published previously by Zobel (1988a). The occurrence of taxa on tree boles was systematically related to the distance from the pollution source and to the altitude from sea level. Binomial distribution was postulated to describe the random variation and maximum likelihood and quasi-likelihood methods were used. Zobel had pooled the original data by grouping distance and altitude into three qualitative levels. The model for pooled data with qualitative factors generally had a poor fit. We assigned quantitative values, linear and quadratic contrasts, to the altitude and distance levels and a linear by linear interaction term between altitude and distance. In most taxa the interaction appeared significant, and these models had generally a better fit and smaller overdispersion than qualitative models. Finally, more effective analysis was performed on the original plotwise data utilizing unpublished quantitative information for distance and altitude. Most species (16/19) had a significant and usually positively monotone response to distance. In the majority of these (10/16) the effect of distance varied between the altitude levels most often so that the lichens were scarcer at low altitude and their increase was faster at high altitude.
Catalytic mechanism of Zn2+-dependent polyol dehydrogenases: kinetic comparison of sheep liver sorbitol dehydrogenase with wild-type and Glu154→Cys forms of yeast xylitol dehydrogenase
Authors: Klimacek Mario , Hellmer Heidemarie , Nidetzky Bernd 
Published: May 2007

Co-ordination of catalytic Zn2+ in sorbitol/xylitol dehydrogenases of the medium-chain dehydrogenase/reductase superfamily involves direct or water-mediated interactions from a glutamic acid residue, which substitutes a homologous cysteine ligand in alcohol dehydrogenases of the yeast and liver type. Glu154 of xylitol dehydrogenase from the yeast Galactocandida mastotermitis (termed GmXDH) was mutated to a cysteine residue (E154C) to revert this replacement. In spite of their variable Zn2+ content (0.10–0.40 atom/subunit), purified preparations of E154C exhibited a constant catalytic Zn2+ centre activity (kcat) of 1.19±0.03 s−1 and did not require exogenous Zn2+ for activity or stability. E154C retained 0.019±0.003% and 0.74±0.03% of wild-type catalytic efficiency (kcat/Ksorbitol=7800±700 M−1· s−1) and kcat (=161±4 s−1) for NAD+-dependent oxidation of sorbitol at 25 °C respectively. The pH profile of kcat/Ksorbitol for E154C decreased below an apparent pK of 9.1±0.3, reflecting a shift in pK by about +1.7–1.9 pH units compared with the corresponding pH profiles for GmXDH and sheep liver sorbitol dehydrogenase (termed slSDH). The difference in pK for profiles determined in 1H2O and 2H2O solvent was similar and unusually small for all three enzymes (≈+0.2 log units), suggesting that the observed pK in the binary enzyme–NAD+ complexes could be due to Zn2+-bound water. Under conditions eliminating their different pH-dependences, wild-type and mutant GmXDH displayed similar primary and solvent deuterium kinetic isotope effects of 1.7±0.2 (E154C, 1.7±0.1) and 1.9±0.3 (E154C, 2.4±0.2) on kcat/Ksorbitol respectively. Transient kinetic studies of NAD+ reduction and proton release during sorbitol oxidation by slSDH at pH 8.2 show that two protons are lost with a rate constant of 687±12 s−1 in the pre-steady state, which features a turnover of 0.9±0.1 enzyme equivalents as NADH was produced with a rate constant of 409±3 s−1. The results support an auxiliary participation of Glu154 in catalysis, and possible mechanisms of proton transfer in sorbitol/xylitol dehydrogenases are discussed.
The Development of the Text Reception Threshold Test: A Visual Analogue of the Speech Reception Threshold Test
Authors: Zekveld Adriana A. , George Erwin L. J. , Kramer Sophia E. , Goverts S. Theo , Houtgast Tammo 
Published: May 2007

Purpose
In this study, the authors aimed to develop a visual analogue of the widely used Speech Reception Threshold (SRT; R. Plomp & A. M. Mimpen, 1979b) test. The Text Reception Threshold (TRT) test, in which visually presented sentences are masked by a bar pattern, enables the quantification of modality-aspecific variance in speech-in-noise comprehension to obtain more insight into interindividual differences in this ability.

Method

Using an adaptive procedure similar to the SRT test, the TRT test determines the percentage of unmasked text needed to read 50% of sentences correctly. SRTs in stationary noise (SRT
STAT
), modulated noise (SRT
MOD
), and TRTs were determined for 34 participants with normal hearing, aged 19 to 78 years.

Results

The results indicate that about 30% of the variance in SRT
STAT
and SRT
MOD
is shared with variance in TRT, which reflects the shared involvement of a modality-aspecific cognitive or linguistic ability in forming meaningful wholes of fragments of sentences.

Conclusion
The TRT test, a visual analogue of the SRT test, has been developed to measure the variance in speech-in-noise comprehension associated with modality-aspecific cognitive skills. In future research, normative data of the TRT test should be developed. It would also be interesting to measure TRTs of individuals experiencing difficulties understanding speech.
Measures of the Glottal Source Spectrum
Authors: Kreiman Jody , Gerratt Bruce R. , Antoñanzas-Barroso Norma 
Published: May 2007

Purpose
Many researchers have studied the acoustics, physiology, and perceptual characteristics of the voice source, but despite significant attention, it remains unclear which aspects of the source should be quantified and how measurements should be made. In this study, the authors examined the relationships among a number of existing measures of the glottal source spectrum, along with the association of these measures to overall spectral shapes and to glottal pulse shapes, to determine which measures of the source best capture information about the shapes of glottal pulses and glottal source spectra.

Method
Seventy-eight different measures of source spectral shapes were made on the voices of 70 speakers. Principal components analysis was applied to measurement data, and the resulting factors were compared with factors similarly derived from oral speech spectra and glottal pulses.

Results
Results revealed high levels of duplication and overlap among existing measures of source spectral slope. Further, existing measures were not well aligned with patterns of spectral variability. In particular, existing spectral measures do not appear to model the higher frequency parts of the source spectrum adequately.

Conclusion
The failure of existing measures to adequately quantify spectral variability may explain why results of studies examining the perceptual importance of spectral slope have not produced consistent results. Because variability in the speech signal is often perceptually salient, these results suggest that most existing measures of source spectral slope are unlikely to be good predictors of voice quality.
Determination of Phonation Instability Pressure and Phonation Pressure Range in Excised Larynges
Authors: Zhang Yu , Reynders William J. , Jiang Jack J. , Tateya Ichiro 
Published: May 2007

PurposeThe present study was a methodological study designed to reveal the dynamic mechanisms of phonation instability pressure (PIP) using bifurcation analysis. Phonation pressure range (PPR) was also proposed for assessing the pressure range of normal vocal fold vibrations.MethodThe authors first introduced the concept of bifurcation on the basis of a symmetric vocal fold model and then applied the bifurcation analysis to data from excised larynges. By recording acoustic signals from 10 excised larynges, the authors measured phonation threshold pressure (PTP), PIP, and PPR at the bifurcation pressure points from the spectrograms as subglottal pressure was progressively increased. Furthermore, to investigate the effects of vocal fold elongation on PTP, PIP, and PPR, the authors manipulated the elongation of the vocal folds at 0%, 5%, 10%, and 15% of the resting vocal fold length.ResultsThe authors found that PTP, PIP, and PPR were effectively determined using the bifurcation analysis. When vocal fold elongation was increased from 0% to 15%, PTP was significantly increased (p< .001), PIP was not significantly changed (p= .54), and PPR was significantly decreased (p= .003).ConclusionPIP and PPR represent important parameters to assess phonation instability. Bifurcation analysis represents a valuable procedure for revealing the mechanisms behind PTP, PIP, and PPR and for investigating the effects of vocal fold biomechanical parameters on these 3 pressure parameters.
Variation among individual butterflies along a generalist–specialist axis: no support for the ‘neural constraint’ hypothesis
Authors: WEE BRIAN , SINGER MICHAEL C. 
Published: May 2007

Abstract 1. Degree of host specialisation was a continuous variable in a population of Edith’s checkerspot butterfly (Euphydryas editha). A novel host, Collinsia torreyi, had been added to the diet in response to anthropogenic disturbance, and then abandoned prior to the current study. Butterflies either showed no preference or preferred their traditional host, Pedicularis semibarbata.2. Strength of preference for Pedicularis over Collinsia was measured in the field and used to estimate host specialisation of individual butterflies. Efficiency was estimated from the times taken by each insect to perform two tasks: (i) identification of a Pedicularis plant as a host, and (ii) successful initiation of oviposition after the decision to do so had been made.3. There was no clear trend for association between host specialisation and either measure of efficiency. Generalists were not slower than specialists at identifying Pedicularis as a host or at handling it after deciding to oviposit.4. Prior work indicated that generalists paid no detectable cost in terms of reduced discrimination among individuals of their preferred host species.5. In contrast to other species, generalist E. editha paid in neither time nor accuracy. Why then does the diet not expand? Behavioural adaptations to the traditional host caused maladaptations to the novel host and generated short‐term constraints to evolutionary expansion of diet breadth. To date, however, no long‐term constraints have been found in this system. In those traits investigated to date, increased adaptation to the novel host has not caused reduced adaptation to the traditional host.
Reproductive allocation in multinest colonies of the ponerine antPachycondyla goeldii
Authors: DENIS DAMIEN , PEZON ANTOINE , FRESNEAU DOMINIQUE 
Published: May 2007

Abstract1. Pachycondyla goeldiiconstitutes the only recorded case of a monogynous (i.e. one queen per colony) polydomous (i.e. several nests per colony) species in thePonerinaesubfamily. This study examines the impact of polydomy on reproductive allocation between nests (also called ‘calies’ in polydomous society) inPachycondyla goeldiiForel, by: (i) recording the number of workers and sexuals in 67 nests belonging to 21 colonies; (ii) dissection of workers in nine nests containing a queen (QR nests), nine nests without a queen but associated to a QR nest (QL nests) and five nests belonging to colonies that permanently lost the queen (OR nests); and (iii) measuring the length of all eggs present in the nests (our laboratory study shows that queen‐laid eggs were significantly longer than worker‐laid eggs).2. The number of workers was significantly higher in QR nests than in QL nests, while the number of virgin queens was significantly higher in QL nests compared with QR nests.3. Worker ovarian activity is inversely related to queen proximity: highest in OR nests, intermediate in QL nests, and lowest in QR nests.4. Egg length was highest in QR nests, where the queen was most likely the primary egg‐layer, intermediate in QL nests, where eggs could have originated from both the queen and workers, and lowest in OR nests, where workers were the sole egg‐layers.5. We postulate that the proximal mechanism explaining differences between QR and QL nests is the pheromonal absence of the queen from QL nests and that the evolutionary reasons of these divergences between nest types are likely to originate from the different conflicts occurring in ant colonies.
Environmental and geographical determinants of beta diversity of leaf beetles (Coleoptera: Chrysomelidae) in the Iberian Peninsula
Authors: BASELGA ANDRÉS , JIMÉNEZ‐VALVERDE ALBERTO 
Published: May 2007

Abstract 1. The effect and relative importance of both environmental and geographic factors on species turnover of Chrysomelidae assemblages in the Iberian Peninsula was explored.2. Ordination and classification analysis of species lists from well‐sampled local areas identified two main biogegraphic groups of inventories, discriminating between Eurosiberian and Mediterranean faunas.3. After describing this pattern, the underlying determinants were explored, separating pure from combined effects of environment and geography by means of partial canonical correspondence analysis.4. Results indicate that pure effects of environment and geographic position are of similar magnitude (about 20% of the variation from each), and quite important in comparison with combined effects.5. The power of the pure effect of geographical variables, together with beta‐diversity independence of species richness gradients, point to the inadequacy of environmental measurement explanation of beta‐diversity patterns, and to the existence of a major component of geographical variation independent of environment.
Marquardt optimization of gravity anomalies of anticlinal and synclinal structures with prescribed depth‐dependent density
Authors: Chakravarthi V. , Sundararajan N. 
Published: May 2007

ABSTRACTAn inversion technique using the Marquardt optimization is developed to interpret the gravity anomalies due to anticlinal and synclinal structures with density contrast varying continuously with depth. The algorithm simultaneously estimates the parameters of the respective models, in addition to the regional gravity background that is invariably associated with the residual gravity anomaly. Forward modelling is realized through analytically derived gravity expressions for the respective models in the space domain. The efficacy of the inversion is demonstrated with the gravity anomaly due to a theoretical model, in each case with and without the regional background. In addition, the applicability is illustrated using the gravity anomalies of the Pays De Bray anticline, situated north‐west of Paris, France. The interpreted depth of the Pays De Bray anticline using the present inversion compares well with the drilling depth.
Nature of the scattered seismic response from zones of random clusters of cavities and fractures in a massive rock
Authors: Leviant V.B. , Petrov I.B. , Chelnokov F.B. , Antonova I.Y. 
Published: May 2007

ABSTRACTThe scattering of elastic energy by random clusters of fractures and/or cavities in a massive rock is studied. The interpretation of the scattered seismic response reveals crucial information about the clusters of inhomogeneities (fractures/cavities), which may correspond to reservoirs. The study is based on a new two‐dimensional numerical‐modelling method that relaxes the constraints on the location and orientation of the inhomogeneities, accounts for inhomogeneities that have almost no volume but a finite surface area (fractures) and improves the accuracy of the calculation when the size of the inhomogeneities is comparable to the mesh size.It is shown that the nature of the seismic response of zones of diffuse fracturing and/or cavities is associated with the non‐uniformity of micro‐inhomogeneities in such zones; accumulations of these micro‐inhomogeneities are known as clusters.The relationship between the non‐uniformity of micro‐inhomogeneities and the strength of the seismic response has been established and measured.Considerable differences in the structure of the seismic response of zones of diffuse fracturing and diffuse cavities have been identified. Converted PS‐waves dominate in the scattered wavefield associated with fractures. This is explained, as the modelling results show, by a greater transparency of fluid‐filled fractures, which reduces the reflected energy of compressional waves. The wavefield associated with cavities is characterized by the predominance (in terms of strength) of compressional PP‐waves. The strength of converted PS‐waves in the scattered wavefields for both media is approximately the same.On the whole, according to the results of the modelling, the energy of the scattered response of fractured reservoirs is considerably less (about two times) than that of cavernous reservoirs.
Barriers to reducing the use of restraints in residential elder care facilities
Authors: Moore Kirsten , Haralambous Betty 
Published: May 2007

Abstract Title. Barriers to reducing the use of restraints in residential elder care facilities Aim.  This paper is a report of a study to compare perspectives of staff in residential elder care facilities with those of residents and family members from the same facilities about barriers to reducing the use of physical, chemical and environmental restraints.Background.  There is growing research evidence of the potential risk of physical and emotional harm of restraining residents in residential elder care facilities. Despite the potential harms, restraints continue to be a common practice in facilities across Australia. Little research has been undertaken to explore the barriers to reducing the use of restraints.Method.  Eighteen individual interviews were conducted with staff, general practitioners and a pharmacist and three focus groups were conducted with a total of 12 residents and 17 family members associated with three residential elder care facilities in Melbourne, Australia in 2004.Findings.  The three participating facilities were committed to reducing the use of restraints, although physical, chemical and environmental restraints were used in all three facilities. Barriers to reducing restraint use included fear of resident injury, staff and resource limitations, lack of education and information about alternatives to restraints, environmental constraints, policy and management issues, beliefs and expectations (of staff, family and residents), inadequate review practices and communication barriers.Conclusion.  Further education and support for staff and family members in evidence‐based practice in relation to resident care and restraint use is needed in at least some residential elder care facilities.
Invasive alien plants infiltrate bird‐mediated shrub nucleation processes in arid savanna
Authors: MILTON S. J. , WILSON J. R. U. , RICHARDSON D. M. , SEYMOUR C. L. , DEAN W. R. J. , IPONGA D. M. , PROCHEŞ Ş. 
Published: May 2007

Summary

The cultivation and dissemination of alien ornamental plants increases their potential to invade. More specifically, species with bird‐dispersed seeds can potentially infiltrate natural nucleation processes in savannas.
To test (i) whether invasion depends on facilitation by host trees, (ii) whether propagule pressure determines invasion probability, and (iii) whether alien host plants are better facilitators of alien fleshy‐fruited species than indigenous species, we mapped the distribution of alien fleshy‐fruited species planted inside a military base, and compared this with the distribution of alien and native fleshy‐fruited species established in the surrounding natural vegetation.
Abundance and diversity of fleshy‐fruited plant species was much greater beneath tree canopies than in open grassland and, although some native fleshy‐fruited plants were found both beneath host trees and in the open, alien fleshy‐fruited plants were found only beneath trees.
Abundance of fleshy‐fruited alien species in the natural savanna was positively correlated with the number of individuals of those species planted in the grounds of the military base, while the species richness of alien fleshy‐fruited taxa decreased with distance from the military base, supporting the notion that propagule pressure is a fundamental driver of invasions.
There were more fleshy‐fruited species beneath native Acacia tortilis than beneath alien Prosopis sp. trees of the equivalent size. Although there were significant differences in native plant assemblages beneath these hosts, the proportion of alien to native fleshy‐fruited species did not differ with host.
Synthesis. Birds facilitate invasion of a semi‐arid African savanna by alien fleshy‐fruited plants, and this process does not require disturbance. Instead, propagule pressure and a few simple biological observations define the probability that a plant will invade, with alien species planted in gardens being a major source of propagules. Some invading species have the potential to transform this savanna by overtopping native trees, leading to ecosystem‐level impacts. Likewise, the invasion of the open savanna by alien host trees (such as Prosopis sp.) may change the diversity, abundance and species composition of the fleshy‐fruited understorey. These results illustrate the complex interplay between propagule pressure, facilitation, and a range of other factors in biological invasions.
Junior medical officer recruitment: Challenges and lessons from the Northern Territory
Authors: McDonald Robert , Sathianathan Vino 
Published: May 2007

AbstractObjective:  To examine the influence of newspaper and Internet advertising, word‐of‐mouth endorsement and student experience in attracting applicants for junior medical officer positions in the Northern Territory. Design:  A retrospective study. Participants:  Fifty‐four applicants for junior medical officer positions. Main outcome measure:  Proportion of applicants who reported newspaper advertising, Internet advertising, word of mouth or personal experience in attracting their application for an intern or resident medical officer position. Results:  Nineteen per cent of applicants saw the newspaper advertisement and 52% of the Internet advertisement. Eighty‐seven per cent of applicants were influenced by word‐of‐mouth endorsement and 52% by student experience in the Northern Territory or Indigenous health. Conclusion:  These results suggest that word‐of‐mouth endorsement has the greatest influence in attracting applicants for junior medical officer positions in Northern Territory hospitals.
Building sustainable rural research capacity: The experiences of a brain injury rehabilitation service
Authors: Salmon Lizette , Curtin Michael , Ginnivan Denis , Neumayer Robert 
Published: May 2007

Abstract There is an emerging recognition of the need for health research that is conducted by and for rural people. Rural research promotes excellence in clinical practice and can improve staff recruitment and retention. A group of clinicians from a regional brain injury service collaborated with academics at their local university to form the Rural Rehabilitation Research on Brain Injury initiative. This initiative has funded four peer‐reviewed research projects, secured an Australian Research Council grant and established the beginnings of a state‐wide rural research collective involving all Brain Injury Rehabilitation Programs in New South Wales. Sustainable research enterprises such as this have significant potential as a ‘prototype’ for building research capacity in other rural health sectors. Governments and funding bodies should support these initiatives.