bluuebunny/crossref_metadata_2025 huggingface dataset:
Quality of oral health services in residential care: towards an evaluation framework
Authors: Pruksapong Mutana , MacEntee Michael I.
Published: October 2007

Background:  There is widespread neglect of oral healthcare, and uncertainty about how best to organise and evaluate the impact of oral health services in long‐term care (LTC) facilities. Consequently, there is need for an evaluation framework to improve and account for the quality of oral healthcare in the facilities.

Objectives:  This paper: (i) identifies basic concepts of quality of care and evaluation in healthcare; (ii) reviews the methods used to evaluate the operation and effectiveness of oral healthcare in LTC facilities and (iii) recommends change to assure oral health‐related quality and accountability for frail elders.

Method:  A literature review provided insights to the theoretical basis and practical applications for assessing the quality of healthcare relevant to oral healthcare for frail elders.

Results:  Oral health‐related programmes in LTC facilities could be improved by using a combination of quality assurance and health programme evaluation that: (i) engages everyone involved; (ii) seeks multiple attributes of quality; (iii) evaluates the structure, process or activities, and outcome of the oral health programme; (iv) uses formative and summative methods to provide both quantitative and qualitative evidence of care and (v) transfers new knowledge for appropriate consideration and action.

Conclusions:  This theoretical framework can be applied in dentistry in LTC to provide an assessment model specific to oral healthcare for frail elders in residential care.
A prospective study on elderly patients with facial fractures in a developing country
Authors: Royan Stephen Joseph , Hamid Abdul Latif , Kovilpillai Ferdinand Jesudian , Junid Nooral Zeila , Mustafa Wan Mahadzir Wan
Published: October 2007

Background:  This paper describes the incidence, aetiology, treatment and complications of facial fractures seen among the elderly in a developing country.

Methods:  A prospective study evaluated 85 patients over 60 years of age who were diagnosed with facial fractures over a period of 12 months in 23 public hospitals nationwide.

Results:  The elderly accounted for 4.5% of the total number of patients seen with facial fractures during the study period. Elderly men outnumbered women by a ratio of 4.31:1. Of the elderly patients, 35.3% had at least one medical condition, the commonest of which was hypertension. Road traffic accidents were the main cause of injury. The fractures were treated in only 26.2% of cases. Complications were uncommon.

Conclusions:  With a low incidence, and conservative treatment often being practised, the healthcare burden of treating facial fractures among the elderly in Malaysia is at present still low.
Relationship between sampling intensity and precision for estimating damage to maize caused by rodents
Authors: MULUNGU Loth S. , MAKUNDI Rhodes H. , MASSAWE Apia W. , LEIRS Herwig
Published: October 2007

In this study we aimed to determine the relationship between sampling intensity and precision for estimating rodent damage. We used the systematic row sampling technique to provide data to achieve precision and accuracy in estimations of rodent damage in maize fields at the planting and seedling stages. The actual rodent damage to maize in 15 fields, each 0.5 ha in size, in Morogoro, Tanzania, was established at the seedling stage. These data were used to simulate the sampling intensities that would provide precision and accuracy. The variations between estimates were plotted against the sampling intervals. The results of this study show that the relationship between average standardized variances and sampling intervals is linear. The heterogeneous distribution of damage in some plots caused variations in the accuracy of the estimates between plots, but a sampling interval of five rows consistently produced estimates with a variance of less than 10%. We provide a standard curve that will allow a decision to be made on the sampling intensity as a function of required precision using the systematic row sampling technique in maize fields.
Linking behavior, life history and food supply with the population dynamics of white‐footed mice (Peromyscus leucopus)
Authors: VESSEY Stephen H. , VESSEY Kristin B.
Published: October 2007

In this paper we review and integrate key aspects of behavioral and life history traits, food supply and population dynamics of the white‐footed mouse (Peromyscus leucopus), a species that is abundant and widely distributed across much of eastern North America. Results are based largely on a 33‐year mark‐and‐recapture study in a forest fragment in northwest Ohio, USA. Behavioral plasticity in such reproductive traits as mating system and parental care allows this species to adjust quickly to changing environments. The species has a relatively “fast” life history, with rapid attainment of sexual maturity and high fecundity in the face of high mortality rates. Maximal reproductive effort early in life enables a rapid population response. Food supply, in the form of mast, determines the size of the reproducing population in early spring, which, in turn, influences the size of the late summer peak population. The peak population size is also affected by short‐term weather events possibly acting via the food supply. The effects of weather and food on population growth are in part mediated through competition, including defense of space and suppression of reproduction. The inelasticity of female territories appears to set an upper limit to population density.
Farmers' knowledge, attitudes, and practices with respect to rodent management in the upland and lowland farming systems of the Lao People's Democratic Republic
Authors: BROWN Peter R. , KHAMPHOUKEO Khamouane
Published: October 2007

Rodents are a serious constraint to poor farmers in the upland and lowland farming systems of the Lao People's Democratic Republic and have been described as the pest they have least control over. To better understand these problems a baseline survey of farmers was conducted to assess their knowledge, attitudes, and practices with respect to rodent management. A structured survey was conducted in 12 villages across Luang Namtha, Luang Prabang, and Houaphan provinces. Twenty farmers from each village were interviewed (a total of 240 farmers). Farmers noted that the main factor limiting production was pests (70%), with rats identified as the most important pest (98%). The mean yield loss was estimated at 19% (range 0–100%). Trapping and rodenticides were commonly used by farmers. Farmers believed that it was important to control rats and believed that rats could only be controlled if farmers worked together. However, 65% of farmers conducted rodent control by themselves, and 92% of farmers believed that rodenticides were harmful to the environment. The main constraints identified were the high cost of some control methods and the need to get farmers to work together as a community.
Rodent community structure in tropical forests in south Vietnam: comparative ecology of two dominant species and implications for conservation
Authors: KUZNETSOV German V. , FILATOVA Tatiana N.
Published: October 2007

Rodents were sampled using the capture‐mark‐recapture technique along transects in disturbed and undisturbed tropical forest in Cat Tien National Park in south Vietnam. The transects comprised two strata: traps were placed on the ground and in the canopy 2–12 m above the ground. At the main transect, which was 1500 m long and located in undisturbed forest, a total of 438 rodents (173 squirrels and 265 murids) of 12 different species (one Scuridae sp.; 11 Muridae spp.) were marked between January 2005 and January 2006. At this study site and at another undisturbed tropical forest site in the same area, two species dominated: the rat Maxomys surifer (Miller, 1900) and the squirrel Callosciurus flavimanus (Geoffroy, 1831). During the study period we observed no significant difference between the average abundances of the two species (4.67 ± 0.86 and 3.1 ± 0.85 individuals per 100 trap nights, respectively) or between the average proportions of resident squirrels and rats (60.0 ± 24.1 and 62.5 ± 11.5, respectively). The number of squirrels that were permanent residents (i.e. dwelling in the same habitat for 1 year) was eightfold the number of rats that were permanent residents. In addition, there was some synchrony in the daily capture dynamics of squirrels and of rats. We observed no significant difference in the total abundance of small mammals between the arboreal and ground strata. At two disturbed tropical forest sites in the same area, however, no such balance between squirrels and rats was observed, and the density of C. flavimanus was very low. We suggest that the relationship between these two dominant species can act as an indicator of the integrity of tropical forest ecosystems in south Vietnam.
Developmental variation in the forest tent caterpillar: life history consequences of a threshold size for pupation
Authors: Etilé Elsa , Despland Emma
Published: October 2007

In insects, size and age at adult emergence depend on larval growth that occurs in discrete steps or instars. Understanding the mechanisms controlling stepwise larval growth and the onset of metamorphosis is essential to the study of insect life history. We examined the patterns of growth of forest tent caterpillars Malacosoma disstria to quantify variation in the number of instars that larvae undergo before pupation, to identify the mechanisms underlying variation in larval development, and to evaluate the life history consequences of this variation. All caterpillars were reared under the same conditions; at each molt, the date, the head capsule width and the mass of the freshly molted insect were recorded. Logistic regression analysis showed that a threshold size (measured either as mass or head capsule width) must be reached at the beginning of a stadium for pupation to occur at the next molt. This threshold size was higher for females than for males, and as a result, females attained a higher pupal mass than males. To achieve this larger size, females often required more instars than males, despite a higher growth ratio (size increase within an instar). Within each sex, slow growing individuals exhibited more larval instars and longer larval development time, but attained the same pupal mass as faster growing individuals. The combination of a threshold size for pupation, discrete growth steps and variation in the number of these steps can thus complicate relationships between growth rate, pupal mass and larval development time. In our study, growth ratio and number of instars were correlated with development time but not with pupal mass, and no relationship was observed between development time and pupal mass. These findings imply that, in species with variable instar number, one cannot extrapolate overall larval growth from growth during a single instar. Given the constraints of discrete larval growth, variation in instar number provides greater flexibility for insects to compensate for poor growing conditions. In this case, inferior larval growth conditions don't necessarily lead to smaller adult size.
A Potential Link from Damage Diagnostics to Health Prognostics of Composites through Built-in Sensors
Authors: Chang Fu-Kuo , Markmiller Johannes F. C. , Ihn Jeong-Beom , Cheng Kok Yen
Published: October 2007

This paper explores the potential of integration of damage diagnostics based on built-in sensors with a progressive failure modeling for monitoring and prediction of composite structures, from damage initiation to final failure while they are in service. A piezobased structural health monitoring system was utilized to monitor the damage initiation based on acoustic signals and to detect its growth based on ultrasonic waves generated by the piezoelectric sensors. Utilizing a damage index and an imaging algorithm, damage initiation and damage extent were estimated, respectively. A finite element code (ABAQUS) based on a progressive failure analysis was adopted to simulate damage initiation and propagation in composites under a given loading condition. The numerical data and the diagnostic images were compared to x-ray pictures of a test coupon to verify the results. The results of the study strongly indicate that damage diagnostics and health prognostics could potentially be integrated to produce a powerful tool for managing the operation of composite structures in service.
Lamb Wave-Mode Tuning of Piezoelectric Wafer Active Sensors for Structural Health Monitoring
Authors: Santoni Giola B. , Yu Lingyu , Xu Buli , Giurgiutiu Victor
Published: October 2007

An analytical and experimental investigation of the Lamb wave-mode tuning with piezoelectric wafer active sensors (PWASs) is presented. The analytical investigation assumes a PWAS transducer bonded to the upper surface of an isotropic flat plate. Shear lag transfer of tractions and strains is assumed, and an analytical solution using the spacewise Fourier transform is reviewed, closed-form solutions are presented for the case of ideal bonding (i.e., load transfer mechanism localized at the PWAS boundary). The analytical solutions are used to derive Lamb wave-mode tuning curves, which indicate that frequencies exist at which the A0 mode or the S0 mode can be either suppressed or enhanced. Extensive experimental tests that verify these tuning curves are reported. The concept of “effective PWAS dimension” is introduced to account for the discrepancies between the ideal bonding hypothesis and the actual shear-lag load transfer mechanism. The paper further shows that the capability to excite only one desired Lamb wave mode is critical for practical structural health monitoring (SHM) applications such as PWAS phased array technique (e.g., the embedded ultrasonics structural radar (EUSR)) and the time reversal process (TRP). In PWAS phased array EUSR applications, the basic assumption of the presence of a single low-dispersion Lamb wave mode (S0) is invoked since several Lamb wave modes traveling at different speeds would disturb the damage imaging results. Examples are given of correctly tuned EUSR images versus detuned cases, which illustrate the paramount importance of Lamb wave-mode tuning for the success of the EUSR method. In the TRP study, an input wave packet is reconstructed at a transmission PWAS when the signal recorded at the receiving PWAS is reversed in the time domain and transmitted back to the original PWAS. Ideally, TRP could be used for damage detection without a prior baseline. However, the application of TRP to Lamb waves SHM is impended by the dispersive and multimodal nature of the Lamb waves. The presence of more then one mode usually produces additional wave packets on both sides of the original wave packet due to the coupling of the Lamb wave modes. The PWAS Lamb wave tuning technique described in this paper is used to resolve the side packets problem. Several tuning cases are illustrated. It is found that the 30kHz tuning of the A0 Lamb wave mode with a 16-count smoothed tone burst leads to the complete elimination of the side wave packets. However, the elimination was less perfect for the 290kHz tuning of the S0 mode due to the frequency sidebands present in the tone-burst wave packet.
3-D Elasticity-Based Modeling of Anisotropic Piezocomposite Transducers for Guided Wave Structural Health Monitoring
Authors: Raghavan Ajay , Cesnik Carlos E. S.
Published: October 2007

Anisotropic piezocomposite transducers (APTs), such as macro fiber composites and active fiber composites, have great potential to be used as structurally integrated transducers for guided-wave (GW) structural health monitoring. Their main advantages over conventional monolithic piezoceramic wafer transducers are mechanical flexibility, curved surface conformability, power efficiency, their ability to excite focused GW fields, and their unidirectional sensing capability as a GW sensor. In this paper, models are developed to describe excitation of GW fields by APTs in isotropic structures. The configurations explored are plane Lamb-wave fields in beams with rectangular cross-section, axisymmetric GW fields in cylinders, and 3-D GW fields in plates. The dynamics of the substrate and transducer are assumed uncoupled. The actuator is modeled as causing shear traction at the edges of the actuator’s active area along the fiber direction. The sensor is modeled as sensing the average extensional strain over the active area along the fiber direction. The work is unique in that the formulation is based on 3-D elasticity, and no reduced-order structural assumptions are used. This is crucial to model multimodal GW propagation, especially at high frequencies. A formulation is also proposed to model the behavior of APTs as GW sensors. Finally, results from experimental tests to examine the validity of the models are discussed and the possible sources of error are examined in detail.
Using Ambient Vibrations to Detect Loosening of a Composite-to-Metal Bolted Joint in the Presence of Strong Temperature Fluctuations
Authors: Nichols J. M. , Trickey S. T. , Seaver M. , Motley S. R. , Eisner E. D.
Published: October 2007

We present an approach for detecting damage-induced nonlinearities in structures. The method first involves the creation of surrogate data sets conforming to an appropriate null hypothesis (no damage). The second step is to then compare some nonlinear “feature” extracted from the original data to those extracted from the surrogates. Statistically significant differences suggest evidence in favor of the alternative hypothesis, damage. Using this approach we show how loose connections can be detected using ambient “wave” forcing, conforming to the Pierson-Moskowitz distribution, as the source of excitation. We also demonstrate the ability of this technique to operate without a recorded baseline data set and in the presence of widely varying temperatures. The structure in this case is a thick, composite beam bolted to a steel frame. Data are collected using an optical strain sensing system. For this experiment we are able to reliably detect the presence of a loosened bolt.
Experimental Enhanced Nonlinear Dynamics and Identification of Attractor Morphing Modes for Damage Detection
Authors: Yin Shih-Hsun , Epureanu Bogdan I.
Published: October 2007

This paper demonstrates two novel methods for identifying small parametric variations in an experimental system based on the analysis of sensitivity vector fields (SVFs) and probability density functions (PDFs). The experimental system includes a smart sensing beam excited by a nonlinear feedback excitation through two lead zirconate titanate patches symmetrically bonded on both sides at the root of the beam. The nonlinear feedback excitation requires the measurement of the dynamics (e.g., velocity of one point at the tip of the beam) and a nonlinear feedback loop, and is designed such that the beam vibrates in a chaotic regime. Changes in the state space attractor of the dynamics due to small parametric variations can be captured by SVFs, which, in turn, are collected by applying point cloud averaging to points distributed in the attractors for nominal and changed parameters. Also, the PDFs characterize statistically the distribution of points in the attractors. The differences between the PDFs of the attractors for different changed parameters and the base line attractor can provide different attractor morphing modes for identifying variations in distinct parameters. Experimental results based on the proposed approaches show that very small amounts of added mass at different locations along the beam can be accurately identified.2
Upper Mantle Discontinuity Topography from Thermal and Chemical Heterogeneity
Authors: Schmerr Nicholas , Garnero Edward J.
Published: October 2007

Using high-resolution stacks of precursors to the seismic phase
SS
, we investigated seismic discontinuities associated with mineralogical phase changes approximately 410 and 660 kilometers (km) deep within Earth beneath South America and the surrounding oceans. Detailed maps of phase boundary topography revealed deep 410- and 660-km discontinuities in the down-dip direction of subduction, inconsistent with purely isochemical olivine phase transformation in response to lowered temperatures. Mechanisms invoking chemical heterogeneity within the mantle transition zone were explored to explain this feature. In some regions, multiple reflections from the discontinuities were detected, consistent with partial melt near 410-km depth and/or additional phase changes near 660-km depth. Thus, the origin of upper mantle heterogeneity has both chemical and thermal contributions and is associated with deeply rooted tectonic processes.
An Alternative Synthesis
Authors: Amundson Ron
Published: October 2007

From Embryology to Evo-Devo
. A History of Developmental Evolution.
Manfred D. Laubichler and Jane Maienschein, Eds.
. MIT Press, Cambridge, MA, 2007. 577 pp. $55, £33.95. ISBN 9780262122832. Dibner Institute Studies in the History of Science and Technology.

The contributors (historians, philosophers, and biologists) explore the status of ontogeny and phylogeny in early 20th-century biology, discuss the roots and current state of evolutionary developmental biology, and consider the interdisciplinary field's future prospects.
THE ROOT SYSTEM OF LINARIA VULGARIS MILL.: I. MORPHOLOGY AND ANATOMY
Authors: Charlton W. A.
Published: October 2007

The morphology and anatomy of the root system of Linaria vulgaris is described. The invasive behavior of the plant is related to the growth habit of the root system and to the formation of buds on the roots. The root system is described in terms of a framework of vigorous long roots, each passing through a phase of horizontal growth followed by a phase of vertical growth. Long roots bear lateral roots which mostly appear to be of restricted growth; long roots of the next order are generally initiated in the region where the direction of growth of the parent long root changed. Any lateral root is thought to be potentially capable of developing as a long root. There are no qualitative grounds for a separation of long and short roots, though most roots are restricted in their growth. Bud initiation is a feature only of roots which have developed as long roots. Root buds are not formed from the long root tissues, but from the bases of some of the lateral roots of the long roots, always in regions where the parent long root passed over from horizontal to vertical growth, and occasionally on the horizontal parts of long roots. Bud formation has only been found to occur when some secondary growth is present in the parent long root.
Bog ericad flowers: self-compatibility and relative attractiveness to bees
Authors: Reader R. J.
Published: October 2007

The seed set of eight bog plants in the Ericaceae family was reduced by excluding insect flower visitors even though hand-pollination tests showed that all eight species were self-compatible. Floral morphology evidently minimizes the possibility that pollen will be transferred from anther to stigma in the absence of insect visitation. Bees were the most important flower visitors, collecting nectar and (or) pollen. The attractiveness (nectar and (or) pollen extractable per minute) of the ericad flowers varied considerably. This variability would promote forager specialization and flowering-timing diversification if the ratio of insect visitors to flowers was low.
Metabolism and translocation of 3-amino-1,2,4-triazole in Pinus pinea
Authors: Lulham G. , Ashtakala S. S. , Lenoir J. A.
Published: October 2007

Metabolism of 3-amino-1,2,4-triazole was studied in 28-day-old seedlings of Pinus pinea injected with 5-14C-labelled 3-amino-1,2,4-triazole into the hypocotyl or tip of one of the 13 cotyledons. The seedlings were allowed to metabolize the labelled triazole for a period of 4, 14, or 21 days and were harvested and separated into cotyledons, apex, hypocotyl, and roots. The label upon extraction from the various parts was partially purified through a Dowex 50 W-8 resin exchange column and eluted with NH4OH and water for thin-layer chromatography. The radioautographs showed several metabolites including unmetabolized amitrole in all parts after 4 days of metabolism. Two of the slower running metabolites correspond to 'unknown I' orX1 and X3 previously reported in Pinus ponderosa and Abies concolor and the two faster running metabolites have not been reported before. The metabolism of amitrole seems to occur in both hypocotyl and cotyledons (sites of injection) and the metabolites, as well as unmetabolized, free amitrole, are transported to all other parts of the plant, concentrating in the apex and cotyledons. Injection of labelled amitrole into the xylem of hypocotyl and root respectively results in upward translocation through the apoplast. Application to the exposed phloem resulted in lateral movement from symplast to apoplast and transport to the upper regions of the seedlings. Injection into one cotyledon resulted in symplastic movement to the apex and hypocotyl, followed by transfer in the hypocotyl to the apoplast and subsequent redistribution to other cotyledons. These patterns of translocation support the proposals put forth by Crafts.
Effects of ε-amino-n-caproic acid and L-lysine on the development of hybrid embryos of triticale (× Triticosecale)
Authors: Taira Tomoaki , Larter E. N.
Published: October 2007

The injection of either ε-amino-n-caproic acid (EACA) or L-lysine–HCl into the tetraploid wheat parent (Triticum turgidum L. var. durum cv. Jori) as early as 1 day after pollination with rye (Secale sp.) significantly enhanced the development of hybrid embryos in vivo. The success with which the embryos could be artificially cultured was improved accordingly. One millilitre of either compound applied at 1.0 mg/ml concentration resulted in a significant increase in the frequency of normal-appearing embryos. It is concluded that the application of EACA or its analogue L-lysine could be used in a hybridization program involving certain strains of wheat and rye to partially overcome the physiological barrier to hybrid embryo development.
The effects of variation in ambient temperature alone and in combination with ε-amino-n-caproic acid on development of embryos from wheat–rye crosses (T. turgidum var. durum cv. Jori × S. cereale)
Authors: Taira Tomoaki , Larter E. N.
Published: October 2007

A study was made on the effect of various temperature regimes on the in vivo development of hybrid embryos from crosses between tetraploid wheat (T. turgidum L. var. durum cv. Jori) and an inbred rye (Secale cereale L.). A day–night temperature of 17–17 °C was found to be optimum for development of embryos as classified on the basis of their morphological features and their level of totipotency in vitro. The application of ε-amino-n-caproic acid (EACA) to the female parent (tetraploid wheat) daily for a 10-day period during embryogenesis significantly improved embryo development but not independently of temperature regime. Both temperature and EACA effects were manifested by increased growth and differentiation of the hybrid embryo; endosperm development was unaffected by treatment.
Regeneration of whole plants from cultured root tips of Limnophila indica
Authors: Rao Sunanda , Ram H. Y. Mohan
Published: October 2007

Root tips (1 cm long) were excised from in vitro grown plants of Limnophila indica (L.) Druce and cultured in liquid medium with 2% sucrose. The explants floated horizontally on the surface of the medium; they became green, and their tips started to grow geotropically into the medium. Four to six shoot buds each were differentiated in 84.5% of the cultures in 4 weeks. Subsequently, shoot buds covered the surface of the bent part of the root and portions above and below it. No buds were formed at the cut end or near the growing root tip. Buds failed to differentiate in roots in which the apex was not growing. Histological studies of the roots showed that the buds originated from proliferating cortical cells, which had prominent chloroplasts and starch grains. The shoot buds grew into entire plants which flowered eventually.
Ontogénie des laticifères du système primaire de l’Hevea brasiliensis: une étude ultrastructurale et cytochimique
Authors: Hébant Charles
Published: October 2007

The development of the laticifers of the primary system in the roots of young seedlings of Hevea is investigated. The nucleus of the maturing secretory cells progressively diminishes in size, thus giving rise to a dense "pycnotic" body. Plastids of primary laticifers show an organization intermediate between that of plastids of neighbouring parenchyma cells and that of the Frey-Wyssling complexes of the secondary laticifers. The continuity of the vacuome sensu lato is underlined. The lutoids, a specialized form of "polydisperse vacuome," show a relationship with the endoplasmic reticulum; these lutoïds can also incorporate rubber particles. The ontogeny of cell wall perforations is described; a progressive hydrolysis of the wall results in its gradual thinning followed by its disruption. Rubber particles are initiated as discrete inclusions within the protoplasm. A thin surface film is identifiable on them, the staining properties of which change during the maturation of the particles. The protoplasm of adult laticifers is densely packed with rubber particles.
Benthic algae in littoral and profundal areas of a deep subarctic lake
Authors: Moore James W.
Published: October 2007

Collections of benthic algae were made in an isolated subarctic lake during July and August 1975. Samples were taken from 30 stations situated at depths of 0.1 to 35 m. The number of species associated with sediments declined with depth from 66 to 22 m. Achnanthes minutissima, Navicula pupula, Cymbella spp., and Nostoc pruniforme reached greatest relative abundance in shallow water whereas Nitzschia palea and Nitzschia dissipata were relatively common below 20 m. Amphora ovalis, Gyrosigma spenceri, and Tabellaria flocculosa did not exhibit a consistent distribution pattern. Standing crops of the epipelon ranged from3 × 106 cells cm−2 (8.5 × 10 μm3 cm−2) at a depth of 0.1–5 m to8 × 103 cells cm−2 (7 × 106 μm3 cm−2) below 20 m. Low light levels, and to a lesser degree, temperature were the most important factors influencing the diversity, species composition, and density of the epipelon in deep water.The epipsammic community consisted of 10 species at all depths. Although Achnanthes pinnata was rare in deep water, the relative abundance of other common species (Amphora ovalis var. pediculus, Fragilaria construens var. venter, and Achnanthes minutissima) was constant at all stations. Standing crops varied from 3.5 × 104 cells cm−2 (39 × 106 μm3 cm−2) at 0.1–5 m to0.3 × 104 cells cm−2 (0.3 × 106 μm3 cm−2) below 20 m. Although low light levels probably controlled densities in deep water, physical characteristics of the substrate determined the diversity and species composition of the community.
Evidence for pathogenicity of Fusarium sporotrichioides to Eurasian water milfoil, Myriophyllum spicatum
Authors: Andrews John H. , Hecht Elizabeth P.
Published: October 2007

Fusarium sporotrichioides Sherb. (= F. tricinctum (Corda) Sacc. emend. Snyd. and Hans.), isolated from diseased Eurasian water milfoil (Myriophyllum spicatum L.), collected in University Bay of Lake Mendota, Wisconsin, was demonstrated to be pathogenic to this species. When inoculated to milfoil grown in flasks, in aquaria, or in the lake, the fungus induced localized elongate, necrotic stem lesions similar to those from which it had been isolated. Plants did not develop necrosis unless wounded by needle puncture or injected with inoculum. On wounded shoots immersed in a spore suspension, systemic apical chlorosis developed within 7–10 days, intensified to a yellow–orange color, and spread proximally to involve about half of the tissue within 2 weeks. The pathogen was reisolated consistently from symptomatic plants following surface sterilization. None of the control plants developed symptoms, and F. sporotrichioides was never isolated from them. The fungus was not highly pathogenic to milfoil. It apparently penetrated mainly, if not exclusively, through wounds and grew extensively in cortical lacunae although its spread was impeded by interruption of the lacunar canals at nodes.
Changes in fungal populations during storage of Dalbergia bark
Authors: Sandhu D. K. , Arora D. S.
Published: October 2007

Nineteen species of fungi were isolated during a 16-week successional study on Dalbergia bark. The most common species present throughout the succession were Aspergillus nidulans and A. fumigatus. Maximum colony forming units (CFU) were recorded during the 3rd week. The highest temperature recorded during the succession was 47 °C. In culture, most of the fungi showed a wide range of temperatures for growth, i.e. 15–47 °C; some were confined to a temperature range of 15–37 °C or 15–32 °C. Most of the fungi, except Acrophialophora fusispora, could utilize cellulose. Only seven fungi showed some lignin utilizing capacity.
The pollination mechanism and development after bud burst of cones of Larix laricina
Authors: Powell G. R. , Tosh Kathleen J.
Published: October 2007

Pollen-cone and seed-cone development, from bud burst to maturity, was investigated on Larix laricina (Du Roi) K. Koch in three young plantations. The pollination mechanism was emphasized. Pollen cones grew rapidly to shed pollen, shrivelled, and remained on the trees for a year or more. Pollen was directed to the ovular regions by the bracts of the seed cones. Pollen adhered among papillae on the larger of two integument extensions. Degeneration of the centre of the papillate integument tip caused a collapse that drew pollen in as the papillate rim grew inward. This ingrowth was joined by that of the smaller integument extension, resulting in a sealed tubular structure that enclosed a dry micropylar canal. Pollen was held by the ingrown plug of degenerated tissue as the nucellus tip expanded into the base of the canal. As this occurred, the ovules, with or without pollination, grew to ultimate seed size, and the initially small ovuliferous scales overgrew the bracts. First bract, then ovuliferous-scale growth was associated with a double-sigmoid form of cone elongation. In mature cones the bracts decreased and the ovuliferous scales (except near the tip) increased in size acropetally. Key words: bract, integument, ovuliferous scale, pollen cone, seed cone, tamarack or eastern larch.
Heterogeneity in endogenous amino acid pools of Chlamydomonas reinhardtii and C. eugametos
Authors: Thomas James E. , Goertzen Christine A. , Nakamura Kazuo
Published: October 2007

Levels of endogenous amino acid pools were measured for two species of the unicellular green alga Chlamydomonas. In C. reinhardtii, opposite mating types, designated + and −, of strain 137c were examined. The soluble pool of glutamic acid was most abundant in strain 137c−. In strain 137c+ similar levels of this amino acid were present, and high levels of cystine were observed. A soluble pool for the amino acid methionine was not detected in either strain. In opposite mating types of C. eugametos (strain Nos. 9 and 10), a soluble pool of alanine was most abundant, whereas neither cystine nor methionine were detected. When C. reinhardtii strain 137c+ was grown in the dark, cystine was not detectable, and proline markedly increased. Similarly, growth of strain 137c+ on nitrogen-deficient medium supplemented with a limited amount of arginine as a nitrogen source resulted in an apparent disappearance of pools of cystine. No apparent difference in the growth patterns of strains 137c+ and 137c− was observed. Tetrad analysis indicates that the high cystine content found in strain 137c+ is neither a characteristic of mating type nor under control of a single Mendelian gene. Key words: Chlamydomonas reinhardtii, Chlamydomonas eugametos, amino acid pool, cystine.
Immunocytochemical localization of tomato pectinesterase in root cells of tomato plants infected by Fusarium oxysporum f.sp. radicis-lycopersici
Authors: Chamberland Hélène , Ouellette G. B. , Pauzé F. J. , Charest P. M.
Published: October 2007

Polyclonal antibodies produced against a purified commercial pectinesterase obtained from tomato plants permitted ultrastructural localization of this enzyme in the roots of young tomato plants infected by Fusarium oxysporum f.sp. radicis-lycopersici Jarvis & Shoemaker. In inoculated susceptible cultivars, gold labeling for pectinesterase was intense over electrondense material in the cortex intercellular spaces, in altered pit membranes in the vascular cylinder, and in the dense coating material deposited along vessel walls. Contrarily, in resistant or uninoculated susceptible plants, which lacked coating material in vessels, labelling was present but nonabundant in the intercellular spaces. The enzyme was not found in the hyphae, indicating that the labelled pectinesterase was probably of host origin. This study suggests the involvement of the tomato pectinesterase in the host reaction against infection by F. oxysporum f.sp. radicis-lycopersici.Key words: pectinesterase, immunocytochemistry, Fusarium oxysporum f.sp. radicis-lycopersici, tomato.
An ultrastructural karyotype for the fungus Eocronartium muscicola using epifluorescence preselection of pachytene nuclei
Authors: Boehm E. W. A. , McLaughlin D. J.
Published: October 2007

Mithramycin-stained nuclei in midpachynema of prophase I were preselected with epifluorescence microscopy as judged by their degree of chomatin condensation. The pachytene nuclei were processed for transmission electron microscopy (TEM) to generate ultrastructural karyotypes for Eocronartium muscicola (Fr.) Fitz. using three-dimensional reconstructions from serial sections of synaptonemal complexes. This is the first report of the use of epifluorescence to preselect fungal pachytene nuclei prior to serial sectioning for TEM and the first ultrastructural karyotype for a heterobasidiomycete. Preselection helped ensure that nuclei were in comparable states of chromatin condensation and influenced the accuracy of cross-correlating bivalent length measurements. Seventeen synapsed homologues were resolved in each of six fully reconstructed pachytene nuclei, originating from two different moss hosts, and four yielded comparable total genomic length measurements. Six of the 17 bivalents were cross-correlated among the four nuclei based on calculated length and centromeric index: the shortest and longest most extreme metacentric and submetacentric bivalents, and the bivalent associated with the nucleolus and the spindle pole body (SPB). The SPB-associated bivalent may relate to the heterochromatin found to subtend the SPB in nonpachytene stages. Key words: chromosomes, Eocronartium, epifluorescence, heterobasidiomycete, karyotype, pachynema, synaptonemal complex, spindle pole body, ultrastructure, Uredinales.
Field performance of Elaeagnus commutata and Shepherdia canadensis (Elaeagnaceae) inoculated with soil containing Frankia and vesicular–arbuscular mycorrhizal fungi
Authors: Visser S. , Danielson R. M. , Parkinson D.
Published: October 2007

A field trial was conducted to determine if containerized silverberry (Elaeagnus commutata) and buffalo-berry (Shepherdia canadensis), inoculated with pot culture soil containing vesicular–arbuscular mycorrhizal fungi and Frankia, would outperform uninoculated seedlings when outplanted on oil sands tailings for two growing seasons. The effect of peat versus peat plus mineral soil treatment of the tailings sand on shrub growth and symbiont development was also addressed. Mortality over the first winter was higher for inoculated seedlings than for uninoculated seedlings. After 1 year, shoot height and weight, root weight, nodule weight, and mycorrhizal root length of the inoculated silverberry were approximately two, five, four, six and five times greater, respectively, than those measured in the uninoculated treatment. The same parameters, respectively, for buffalo-berry were approximately one and one-half, four, two, six and two times greater for the inoculated seedlings than for their uninoculated counterparts. The superior growth of the inoculated seedlings was continued over the 2nd year. Soil amendment effects on plant growth and symbiont development over the 1st year were minimal for silverberry but significant for buffalo-berry. Shoot productivity of both shrub species was highly correlated with nodule status. Key words: actinorhizal shrubs, revegetation, N2 fixation, vesicular–arbuscular mycorrhizae, growth response.
Samara development of black maple (Acer saccharum ssp. nigrum) with emphasis on the wing
Authors: Peck Carol Jacobs , Lersten Nels R.
Published: October 2007

Black maple (Acer saccharum Marsh, ssp. nigrum (Michx. f.) Desm.) carpels are initiated in late summer and over winter as paired, hood-shaped primordia with a naked megasporangium on each inrolled margin. The biloculate ovary develops from the lower portion of the primordium. The mature pericarp, about 30 cells thick, includes (i) the exocarp: outer epidermis and one to three layers of thick-walled hypodermal cells; (ii) the mesocarp: about 20 cells thick with reticulate venation and an innermost crystalliferous layer; and (iii) the endocarp: five to eight layers of short fibers oriented parallel to the locule surface. The samara wing arises from the dorsal ridge of the carpel primordium. The wing blade is approximately 10 cell layers thick with unifacial anatomy. Vascular bundles from opposite sides of the carpel alternate within the wing, thus xylem and phloem are oriented oppositely in adjacent bundles. The chlorenchymatous ground tissue ranges from compact subepidermal cells to elongated spongy cells, with increasing lateral orientation of cell arms in the mid-lamina. These central cells become sclerified, forming curved, branched fibers that buttress the vascular framework. Wing development and structure suggest early photosynthetic activity, which declines as sclerification and drying progress. Key words: Acer saccharum, anatomy, development, fruit, maple, samara.
Genotypic and phenotypic variability of Zostera marina on the west coast of North America
Authors: Backman Thomas W. H.
Published: October 2007

The relation between environmental factors and leaf morphology of Zostera marina L. have long been unclear, primarily because the species is intrinsically variable. The common-garden method was used to determine the genetic, environmental, and interaction components of leaf size variation. Zostera marina consists of several ecotypes with a wide range of phenotypic plasticity. Variation in the morphology of Z. marina was of three types: genetic, accounting for 14% across the localities studied; environmental (phenotypic plasticity along temporal and spatial gradients), accounting for 32%; and interaction between genotype and environmental, acounting for 35%. Five ecotypes were described for the North American Pacific coast: Z. marina L. var. izembekensis Backman, Z. marina L. var. typica Setchell, Z. marina L. var. phillipsii Backman, Z. marina L. var. latifolia Morong, Z. marina L. var. atàm Backman. Temporal variation was due to seasonal phenotypic changes in ecotypes. Zostera marina var. izembekensis showed little seasonal morphological changes; Z. marina var. typica demonstrated minor increase in leaf size in spring and summer. Zostera marina var. phillipsii and Z. marina var. latifolia behaved similarly in that leaf size of both increased markedly in spring through early summer. Zostera marina var. phillipsii is adapted to Hood Canal and Puget Sound while Z. marina var. latifolia occupies the outer coast. Zostera marina var. atàm exhibits sexual reproduction exclusively and is specifically adapted to the Gulf of California. Key words: seagrasses, common-garden experiment, ecotypes, morphometrics, genotypes.
The synaptonemal complexes of Achlya recurva (Oomycetes): karyotype analysis and three-dimensional reconstruction of pachytene nuclei in antheridia and oogonia
Authors: Williamson Hobart R. , Yitzchak Pesach Ben
Published: October 2007

Fifteen synaptonemal complexes, as determined by three-dimensional reconstruction of serial, ultrathin sections, were present within both antheridial and oogonial zygotene and pachytene nuclei of the oomyceteous fungus Achlya recurva, thus n = 15. The present study represents the first complete reconstruction of synaptonemal complexes in the genus Achlya. The occurrence of both zygonema and pachynema was simultaneous in antheridia and oogonia. Pachytene nuclei of antheridia and oogonia are small, 13 μm3 in volume, and the average length of the synaptonemal complexes ranged from 1.9 to 4.4 μm. Lateral elements at zygotene ranged from 1.2 to 4.7 μm. Both ends of each synaptonemal complex were attached randomly to the nuclear envelope, so a bouquet formation was not observed at pachytene. In A. recurva, the dimensions of the synaptonemal complex were as follows: overall width = 270 nm; the lateral elements = 75 nm each in width and the central region = 120 nm. There was no central element and associated transverse filaments, which may be associated with development of alternative reproductive strategies other than amphimixis, as in nematodes. Of the 15 synaptonemal complexes present, only the one carrying the nucleolus organizer region could be clearly identified from one nucleus to the next. The nucleolar organizer region was on the average 0.75 μm from the telomere in both zygotene and pachytene nuclei. There were an average of three recombination nodules in each nucleus. Synaptonemal complexes have been reported in over 80 different species of fungi and related protista. Karyotypic evolution in the oomycetes and fungi may be the result of poly-ploidization, followed by cytogenetic diversification involving aneuploidy and differing degrees of polyploidy. Such a sequence of events could explain the apparent polyphyletic formation of this group. Key words: karyotype, Oomycetes, pachytene, synaptonemal complexes, three-dimensional reconstruction.
Microenvironmental correlates of phenotypic variation in Capsella bursa-pastoris (Cruciferae)
Authors: Paoletti Claudia , Pigliucci Massimo , Serafini Mauro
Published: October 2007

The majority of papers dealing with environmental correlates of phenotypic variability are concerned with macrogeographical structuring of the investigated species. However, a possible major component of phenotypic differentiation in some taxa is small-scale variability in the microenvironment. The statistical methods usually employed for such studies seems to be restricted to a few standardized sets of procedure, often assuming linearity and additivity of effects among variates. In this paper we studied small-scale geographical differentiation of phenotypes of Capsella bursa-pastoris (Cruciferae), a species characterized by an apparent extreme degree of phenetic specialization that could be due to fixation of alternative alleles in small local demes. We use nonparametric multivariate procedures to test the relationships between phenotypic principal components, geographic distance, and a number of microenvironmental parameters. A concept recently applied to population genetics, that of biological boundaries, is used here in relation to phenetic variation to assess its association with geographical mapping of the populations studied. Key words: Capsella, Mantel test, phenotypic boundaries, biotic parameters, principal components analysis.