bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevated CO2 reduces leaf damage by insect herbivores in a forest community
Authors: Knepp Rachel G. , Hamilton Jason G. , Mohan Jacqueline E. , Zangerl Arthur R. , Berenbaum May R. , DeLucia Evan H. 
Published: June 2005

Summary

By altering foliage quality, exposure to elevated levels of atmospheric CO2 potentially affects the amount of herbivore damage experienced by plants.
Here, we quantified foliar carbon (C) and nitrogen (N) content, C : N ratio, phenolic levels, specific leaf area (SLA) and the amount of leaf tissue damaged by chewing insects for 12 hardwood tree species grown in plots exposed to elevated CO2 (ambient plus 200 µl l−1) using free‐air CO2 enrichment (FACE) over 3 yr.
The effects of elevated CO2 varied considerably by year and across species. Elevated CO2 decreased herbivore damage across 12 species in 1 yr but had no detectable effect in others. Decreased damage may have been related to lower average foliar N concentration and SLA and increased C : N ratio and phenolic content for some species under elevated compared with ambient CO2. It remains unclear how these changes in leaf properties affect herbivory.
Damage to the leaves of hardwood trees by herbivorous insects may be reduced in the future as the concentration of CO2 continues to increase, perhaps altering the trophic structure of forest ecosystems.
Activity profiling of ectomycorrhiza communities in two forest soils using multiple enzymatic tests
Authors: Courty Pierre‐Emmanuel , Pritsch Karin , Schloter Michael , Hartmann Anton , Garbaye Jean 
Published: June 2005

Summary

Data on the diversity and distribution of enzyme activities in native ectomycorrhizal (ECM) communities are inadequate.
A microplate multiple enzymatic test was developed which makes it possible to measure eight enzyme activities on 14 individual, excised ECM root tips. Hydrolytic and oxidative enzymes are involved in the decomposition of lignocellulose, chitin and phosphorus‐containing organic compounds. This test system was used to describe the functional diversity of ECM communities in two forest sites.
This set of tests proved to be accurate and sensitive enough to reveal a high diversity of activity profiles, depending on the fungal symbiont and the soil horizon. Ectomycorrhizas can be classified into specialists and generalists, and appear to complement each other in the same horizon to collectively perform all eight activities studied.
By including a higher number of different assays for more detailed analyses, ECM activity profiling will provide a valuable tool for studying the functional diversity of ECM communities.
Links between tree species, symbiotic fungal diversity and ecosystem functioning in simplified tropical ecosystems
Authors: Lovelock Catherine E. , Ewel John J. 
Published: June 2005

Summary

We studied the relationships among plant and arbuscular mycorrhizal (AM) fungal diversity, and their effects on ecosystem function, in a series of replicate tropical forestry plots in the La Selva Biological Station, Costa Rica.
Forestry plots were 12 yr old and were either monocultures of three tree species, or polycultures of the tree species with two additional understory species. Relationships among the AM fungal spore community, host species, plant community diversity and ecosystem phosphorus‐use efficiency (PUE) and net primary productivity (NPP) were assessed.
Analysis of the relative abundance of AM fungal spores found that host tree species had a significant effect on the AM fungal community, as did host plant community diversity (monocultures vs polycultures). The Shannon diversity index of the AM fungal spore community differed significantly among the three host tree species, but was not significantly different between monoculture and polyculture plots. Over all the plots, significant positive relationships were found between AM fungal diversity and ecosystem NPP, and between AM fungal community evenness and PUE. Relative abundance of two of the dominant AM fungal species also showed significant correlations with NPP and PUE.
We conclude that the AM fungal community composition in tropical forests is sensitive to host species, and provide evidence supporting the hypothesis that the diversity of AM fungi in tropical forests and ecosystem NPP covaries.
The potential for adaptive evolution of pollen grain size in Mimulus guttatus
Authors: Lamborn Ellen , Cresswell James E. , Macnair Mark R. 
Published: June 2005

Summary

We tested whether pollen grain size (PGS) shows heritable variation in three independent populations of Mimulus guttatus by imposing artificial selection for this character. In addition, we looked for correlated responses to selection in a range of 15 other floral characters.
Heritable variation in PGS was found in all three populations, with heritabilities of between 19 and 40% (average 30%). After three generations, upward and downward lines differed on average by 30% in pollen volume.
No consistent patterns of correlated response were found in other characters, indicating that PGS can respond to selective forces acting on PGS alone.
Possible selection mechanisms on PGS in this species could include intermale selection, if large pollen grains produce more competitive gametophytes; or optimization of patterns of resource allocation, if local mate competition varies.
Genetic transformation: a powerful tool for dissection of adaptive traits in trees
Authors: Busov Victor B. , Brunner Amy M. , Meilan Richard , Filichkin Sergei , Ganio Lisa , Gandhi Sonali , Strauss Steven H. 
Published: June 2005

SummaryPlant transformation and regeneration systems have become indispensable parts of gene discovery and functional characterization over the last two decades. Adoption of transformation methods in studies of plant adaptation to natural environments has been slow. This is a result of poor genomic knowledge and inefficient transformation systems for species dominating terrestrial ecosystems, and logistical difficulties in conducting field tests of genetically engineered organisms. In trees, where long generation cycles, high background polymorphism, large sizes and outcrossing systems of mating make production of near‐isogenic lines and large experiments difficult, transformation is an attractive alternative for establishing direct linkages between genes and adaptively significant phenotypes. Here, we outline the capabilities, challenges, and prospects for transformation to become a significant tool for studying the ecophysiological adaptation of trees to the environment. Focusing on poplars (genusPopulus) as model system, we describe how transformation‐based approaches can provide insights into the genes that control adaptive traits. The availability of the poplar genome sequence, along with its large expressed sequences tag (EST) databanks, facile transformation and rapid growth, enable reverse genetic approaches to be used to test virtually any hypothesis of gene function.
Variation in frequency of hybrids and spatial structure among Ipomopsis (Polemoniaceae) contact sites
Authors: Aldridge George 
Published: June 2005

Summary

Rates of hybridization vary among angiosperm taxa. Among‐taxon variation in hybridization rate has been used to compare the importance of pre‐ and post‐zygotic reproductive isolating mechanisms. Variation in rates of hybridization within a single‐species pair would suggest that local conditions also affect reproductive isolation within a single taxonomic context.
In this study, contact sites of Ipomopsis aggregata–Ipomopsis tenuituba were surveyed for variation in frequency of hybrids, and spatial structure. Floral morphology was used to identify parent species and hybrids in seven contact sites in the western Rocky Mountains, USA.
Contact sites varied widely in elevational range, the degree to which morphological variation was clinal rather than mosaic and the frequency of hybrids. Two sites provided a strong contrast between a clinal, unimodal site and a mosaic, bimodal site.
This natural variation among contact sites of the same species pair provides an opportunity to assess the effect of local ecological conditions and spatial structure of parent populations on reproductive isolation, while controlling for between‐taxon variation.
The influence of cycloplegia in objective refraction
Authors: Jorge J. , Queiros A. , González‐Méijome J. , Fernandes P. , Almeida J. B. , Parafita M. A. 
Published: June 2005

AbstractThe purpose of this study was to compare refractions measured with an autorefractor and by retinoscopy with and without cycloplegia. The objective refractions were performed in 199 right eyes from 199 healthy young adults with a mean age of 21.6 ± 2.66 years. The measurements were performed first without cycloplegia and repeated 30 min later with cycloplegia. Data were analysed using Fourier decomposition of the power profile. More negative values of component M and J0 were given by non‐cycloplegic autorefraction compared with cycloplegic autorefraction (p < 0.0001). However more positive values for the J45 vector were given by non‐cycloplegic autorefraction, although this difference was not statistically significant (p = 0.233). By retinoscopy, more negative values of component M were obtained with non‐cycloplegic retinoscopy (p < 0.0001); for the cylindrical vectors J0 and J45 the retinoscopy without cycloplegia yields more negative values (p = 0.234; p = 0.112, respectively). Accepting that differences between cycloplegic and non‐cycloplegic retinoscopy are only due to the accommodative response, the present results confirm that when performed by an experienced clinician, retinoscopy is a more reliable method to obtain the objective starting point for refraction under non‐cycloplegic conditions.
Evaluation of Melbourne Edge Test contrast sensitivity measures in the visually impaired
Authors: Wolffsohn James S. , Eperjesi Frank , Napper Genevieve 
Published: June 2005

AbstractAim:  Contrast sensitivity (CS) provides important information on visual function. This study aimed to assess differences in clinical expediency of the CS increment‐matched new back‐lit and original paper versions of the Melbourne Edge Test (MET) to determine the CS of the visually impaired.Methods:  The back‐lit and paper MET were administered to 75 visually impaired subjects (28–97 years). Two versions of the back‐lit MET acetates were used to match the CS increments with the paper‐based MET. Measures of CS were repeated after 30 min and again in the presence of a focal light source directed onto the MET. Visual acuity was measured with a Bailey–Lovie chart and subjects rated how much difficulty they had with face and vehicle recognition.Results:  The back‐lit MET gave a significantly higher CS than the paper‐based version (14.2 ± 4.1 dB vs 11.3 ± 4.3 dB, p < 0.001). A significantly higher reading resulted with repetition of the paper‐based MET (by 1.0 ± 1.7 dB, p < 0.001), but this was not evident with the back‐lit MET (by 0.1 ± 1.4 dB, p = 0.53). The MET readings were increased by a focal light source, in both the back‐lit (by 0.3 ± 0.81, p < 0.01) and paper‐based (1.2 ± 1.7, p < 0.001) versions. CS as measured by the back‐lit and paper‐based versions of the MET was significantly correlated to patients’ perceived ability to recognise faces (r = 0.71, r = 0.85 respectively; p < 0.001) and vehicles (r = 0.67, r = 0.82 respectively; p < 0.001), and with distance visual acuity (both r = −0.64; p < 0.001).Conclusions:  The CS increment‐matched back‐lit MET gives higher CS values than the old paper‐based test by approximately 3 dB and is more repeatable and less affected by external light sources. Clinically, the MET score provides information on patient difficulties with visual tasks, such as recognising faces.
The morphometric analysis of the central retinal artery
Authors: Kocabiyik Necdet , Yalcin Bulent , Ozan Hasan 
Published: June 2005

AbstractIn this study, we aimed to investigate some features of the central retinal artery (CRA), which supplies the internal aspect of the retina. The CRA is the main vessel supplying blood to the retina. The origin, course and penetration point of the optic nerve by the CRA were studied in 30 human orbits. We compared the right sides to the left sides on the basis of gender in order to statistically analyse the relation between them. The CRA arose directly from the ophthalmic artery in 28 specimens. In two specimens, however, it arose in common with the medial posterior ciliary artery. When we observed the penetration point (site) of the CRA into the optic nerve, in 28 of 30 (93.3%) cases, the artery entered the nerve from the lower medial aspect and in two (6.7%) cases from the upper lateral aspect. The CRA penetrated the optic nerve between 6.4 and 15.2 mm behind the eyeball and reached the eyeball through the centre of the optic nerve. Because of the small diameter of the artery, it has a high risk of getting damaged during a surgical approach to the orbit. Therefore the anatomical relationships of this artery must be well known.
The need for optometric investigation in suspected Meares–Irlen syndrome or visual stress
Authors: Evans Bruce J. W. 
Published: June 2005

AbstractMeares–Irlen syndrome is characterised by symptoms of eye strain, headaches and visual perceptual distortions when viewing text. The symptoms are alleviated with individually prescribed coloured filters, such as precision tinted lenses. Meares–Irlen syndrome, and the related condition of visual stress, are likely to result from hyperexcitability of the visual cortex, which can also occur in migraine. The symptoms of Meares–Irlen syndrome and visual stress are non‐specific and the condition needs to be differentially diagnosed from other optometric conditions, such as refractive error, binocular vision anomalies, and accommodative anomalies. Three case reports are described of patients who consulted the author with suspected Meares–Irlen syndrome but were found to have other causes for their symptoms: posterior sub‐capsular cataract, high uncorrected astigmatism, and decompensated convergence weakness exophoria. These cases highlight the need for professional eye care for people with suspected Meares–Irlen syndrome. Although this advice is stressed in literature on the well‐established MRC/Wilkins Intuitive Colorimeter system, it is not always stressed in literature about other systems. This may be a cause for concern.
Eye fixation scanpaths of younger and older drivers in a hazard perception task
Authors: Underwood Geoffrey , Phelps Nicola , Wright Chloe , Van Loon Editha , Galpin Adam 
Published: June 2005

AbstractOur previous research has shown that observing patterns of eye fixations is a successful method of establishing differences in underlying cognitive processes between groups of drivers. Eye movements recorded from drivers in a laboratory while they watch film clips recorded from a driver's perspective can be used to identify scanpaths and search patterns that reveal ability differences. In the present study 12 older subjects (60–75 years) and 12 younger subjects (30–45 years) watched clips for potential hazards such as other road users appearing on an intersecting trajectory. Acuity and visual field differences between the two groups were eliminated through screening, so that only age‐related differences would emerge. Eye fixations were analysed on a frame‐by‐frame basis to generate sequences of codes representing the location and object of the viewer's interest, before and during the appearance of a hazard. These codes were analysed for the existence of two fixation scanpaths using Markov Matrices. Unique scanpaths were identified for each group of drivers before and during the hazard. Evidence from the inspection of different objects and from the spread of the search indicated that both groups of driver were sensitive to attentional capture by the appearance of the hazard. Detection of the hazards – both speed and accuracy – was similar for older and younger drivers, although the older drivers perceived the films as being more hazardous in general. There is little evidence in this study of an age‐related decline in the search of the scene when detecting hazards.
Characteristics of pupil responses during far‐to‐near and near‐to‐far accommodation
Authors: Kasthurirangan Sanjeev , Glasser Adrian 
Published: June 2005

AbstractThe static and dynamic aspects of the pupil response associated with various amplitudes of far‐to‐near (accommodation) and near‐to‐far (disaccommodation) focusing responses were evaluated in this study. Dynamic refractive and pupillary changes were measured simultaneously during focusing responses to targets at real distances in 12 young (23–26 years) emmetropic subjects. The targets were presented alternately at far (6 m) and at one of six near positions from 1 D (1 m) to 6 D (16.7 cm) in 1 D steps. The latency, magnitude and peak velocity of pupil changes associated with accommodation and disaccommodation responses were calculated. The latency of refractive changes was shorter than that of pupillary changes. In general, the pupil constricted with accommodation and started dilating while accommodation was still maintained, resulting in reduced pupil dilation with disaccommodation. The magnitude of the pupil response increased linearly with that of accommodation and disaccommodation. The amount of pupil change per dioptre of refractive change was invariant with various amplitudes of refractive change. The peak velocity of pupil constriction was greater than that of pupil dilation for corresponding amplitudes. The pupil response is more closely associated with accommodation than with disaccommodation.
Aberrations and myopia
Authors: Charman W. N. 
Published: June 2005

AbstractIt has been suggested that high levels of axial aberration or specific patterns of peripheral refraction could play a role in myopia development. Possible mechanisms involving high levels of retinal image blur caused by axial aberrations include form deprivation through poor retinal image quality in distance vision, enhanced accommodative lags favouring compensatory eye growth, and an absence of adequate directional cues to guide emmetropization. In addition, in initially emmetropic eyes, hyperopia in the retinal periphery may result in local compensatory eye growth, which induces axial myopia. Evidence in support of these ideas is reviewed and it is concluded that, for any fixed pupil diameter, evidence for higher levels of axial aberration in myopes in comparison with other refractive groups is weak, making involvement of axial aberrations in myopization through image degradation at the fovea unlikely. If, however, some potential myopes had unusually large pupil diameters, their effective aberration levels and associated retinal blur would be larger than those of the rest of the population. There is stronger evidence in favour of differences in patterns of peripheral refraction in both potential and existing myopes, with myopes tending to show relative hyperopia in the periphery. These differences appear to be related to a more prolate eyeball shape. Longitudinal studies are required to confirm whether the retinal defocus associated with the peripheral hyperopia can cause patterns of eyeball growth which lead to axial myopia.
Downward deviation of progressive addition lenses in a myopia control trial
Authors: Hasebe Satoshi , Nakatsuka Chiaki , Hamasaki Ichiro , Ohtsuki Hiroshi 
Published: June 2005

AbstractPurpose:  To clarify how the downward deviation of progressive addition lenses (PALs) reduces their near‐addition effect in schoolchildren participating in a myopia control trial.Methods:  Among 95 schoolchildren wearing PALs for 6 months (age range: 6–12 years; refractive error range: −6.00 to −1.25 D), facial images were captured with a digital still camera placed 60 cm in front of the eyes while he or she was looking ahead with natural head posture. The vertical deviations of PALs from their ideal position (mm) were evaluated by analysing these images.Results:  The mean (±SD) downward deviations of PALs for the right and left eyes were 3.7 ± 2.3 and 3.7 ± 2.0 mm, respectively, and the largest downward deviation was 10.2 mm. For simulations using the average downward deviation, the near‐addition effect of PALs was reduced to 30 and 63% of the expected value at the 10° and 20° downward eye positions, respectively.Conclusions:  The downward deviation of PALs is a significant factor in reducing their therapeutic effect for near‐addition. To ensure the proper alignment of PALs in children, the conventional spectacle‐frame‐fitting procedure is not sufficient, and repeated confirmation using a testing method similar to that used in this study is required.
Refractive error and ocular biometry in Jordanian adults
Authors: Mallen Edward A. H. , Gammoh Yazan , Al‐Bdour Muawyah , Sayegh Fouad N. 
Published: June 2005

AbstractThe aim of this study was to establish the prevalence of refractive errors in Jordanian adults of working age, and to study the ocular biometric correlates of refractive error in this population. Refractive error and ocular biometry were measured in 1093 Jordanian adult subjects aged 17–40 years to determine the prevalence of refractive error, and explore structural correlations of ametropia. Refractive error was measured using a Grand‐Seiko GR‐3100K closed‐view infrared autorefractor. Ocular component measurements were made using A‐scan ultrasonography and autokeratometry. The prevalence of myopia [spherical equivalent refraction (SER) less than −0.50 DS] and hyperopia (SER greater than +0.50 DS) was 53.71 and 5.67% respectively; 40.62% of the sample was emmetropic (refraction between +0.50 D and −0.50 D inclusive in both principal meridians). The distribution of SER was found to show marked leptokurtosis, exhibiting a peak between plano and 1 D of myopia. Corneal radius, anterior chamber depth, crystalline lens thickness, vitreous chamber depth and axial length (AL) parameters were normally distributed in the population studied. AL to corneal curvature ratio was not normally distributed, and showed marked leptokurtosis. Linear regression analysis showed that AL correlated most closely with spherical equivalent refractive error. This study has established a database of refractive error prevalence and ocular biometric correlates of ametropia in a Middle Eastern population of working age.
Optometric and ophthalmic contact in elderly hip fracture patients with visual impairment*
Authors: Cox A. , Blaikie A. , MacEwen C. J. , Jones D. , Thompson K. , Holding D. , Sharma T. , Miller S. , Dobson S. , Sanders R. 
Published: June 2005

AbstractAim:  To describe previous contact with optometry and ophthalmic services in a group of elderly patients with and without visual impairment (VI) who had fallen and sustained a fractured neck of femur.Method:  A cross sectional study of 537 patients aged 65 and over who had undergone hip fracture surgery in four Scottish centres (Glasgow, Ayr, Dundee and Fife). All patients had an in‐depth optometric history, ophthalmic history and examination.Results:  Three hundred and ninety‐three (79%) patients reported optometric contact in the 3 years preceding surgery and 107 (21%) patients had not seen an optometrist for more than 3 years. In the latter group, 64 had VI, which was due to uncorrected refractive error in 17 (27%) and untreated cataract in 20 (31%). VI (best binocular visual acuity of 6/18 or less) was found in 239 (46%) patients. A past ophthalmic history was present in 257 (50%) patients. Only 39 (16%) patients with VI were under ophthalmic care at the time of the study.Conclusions:  There was significantly poor optometric and ophthalmic contact in patients who had VI and had fallen and sustained hip fracture. A proportion of the VI (66%) was due to uncorrected refractive error and untreated cataract. Public health providers should be made aware of the fact that current optometric and ophthalmic care pathways are not accessed by this group of elderly patients with VI and at risk of falling.