Morphological structure of bismuth-doped n-type amorphous germanium sulphide semiconductors

Recent observation of n-type conduction in amorphous Ge20Ss_xBix at large bismuth concentrations (x = 11), which otherwise shows p-type conduction, has aroused considerable interest in the international scientific community [1]. The mechanism of such impurity incorporation in a germanium chalcogenide glass is not understood and is a topic of current interest. In our recent publications [2-10] we have brought to light some hitherto unknown and interesting features of bismuth dopants in chalcogen-rich Ge-X (X -- S, Se) glassy compositions. In this communication we present our new results of investigations on vitreous semiconductors Ge20S80 Bi using electron microscopy, electron diffraction of as-prepared and annealed/pressure quenched compositions. Our results provide conclusive support to the formation of composite clusters containing all the three elements, germanium, sulphur and bismuth, which crystallize in simpler stoichiometric compounds Bi2S3 and GeS2.

The Influence of Constantinople on Middle Byzantine Architecture (843-1204) : A typological and morphological approach at the provincial level.

The influence of the architecture of the Byzantine capital spread to the Mediterranean provinces with travelling masters and architects. In this study the architecture of the Constantinopolitan School has been detected on the basis of the typology of churches, completed by certain morphological aspects when necessary. The impact of the Constantinopolitan workshops appears to have been more important than previously realized. This research revealed that the Constantinopolitan composite domed inscribed-cross type or cross-in-square spread everywhere to the Balkans and it was assumed soon by the local schools of architecture. In addition, two novel variants were invented on the basis of this model: the semi-composite type and the so-called Athonite type. In the latter variant lateral conches, choroi, were added for liturgical reasons. Instead, the origin of the domed ambulatory church was partly provincial. One result of this study is that the origin of the Middle Byzantine domed octagonal types was traced to Constantinople. This is attested on the basis of the archaeological evidence. Also some other architectural elements that have not been preserved in the destroyed capital have survived at the provincial level: the domed hexagonal type, the multi-domed superstructure, the pseudo-octagon and the narthex known as the lite. The Constantinopolitan architecture during the period in question was based on the Early Christian and Late Antique forms, practices and innovations and this also emerges at the provincial level.

Morphological transitions in polymer monolayers under compression

We present a systematic investigation of morphological transitions in poly vinylacetate Langmuir monolayers. On compression, the polymer monolayer is converted to a continuous membrane with a thickness of similar to 2-3 nm. Above a certain surface concentration the monolayer, on water, undergoes a morphological transition-buckling, leading to formation of striped patterns of period of lambda(b)similar to 160 nm, as determined from in situ grazing incidence small angle x-ray scattering measurements. The obtained value is much smaller than what has been typically observed for Langmuir monolayers on water or thin films on soft substrates. Using existing theories for buckling of fluidlike films on fluid substrates, we obtain very low values of bending rigidity and Young's modulus of the polymer monolayer compared to that observed earlier for lipid or polymeric monolayers. Since buckling in these monolayers occurs only above a certain surface concentration, we have looked at the possibility that the buckling in these films occurs due to changes in their mechanical properties under compression. Using the model of Huang and Suo of buckling of solidlike films on viscoelastic substrates, we find values of the mechanical properties, which are much closer to the bulk values but still significantly lower. Although the reduction could be along the lines of what has been observed earlier for ultrathin polymer film or surface layers of polymers, the possibility of micromechanical effects also determining the buckling in such polymer monolayers cannot be ruled out. We have provided possible explanation of the buckling of the poly vinylacetate monolayers in terms of the change in isothermal compression modulus with surface concentration.

Oesophagogastric ulceration in pigs: A visual morphological scoring guide

Objective: To provide a visual guide for oesophagogastric ulcer scoring and recognition of different morphological changes in the pars oesophagea. Design: Pig stomachs were collected at slaughter and visually evaluated and scored for parakeratosis, erosion and ulceration in the pars oesophagea. Results: A visual and descriptive guide is presented that will aid in the objective assessment and scoring of oesophagogastric ulceration in pigs within the pig health monitoring system (PHMS), namely to the four categories of 0 = normal stomach, 1 = parakeratosis and thickened epithelium, 2 = erosions and 3 = developed ulcers with and without stenosis. Conclusion: A visual guide has been developed that illustrates the full range of morphological changes that can occur in the pars oesophagea of the stomach within the few currently recognised stages of the disease.

Characterization of tree-to-tree variation in morphological, nutritional and medicinal properties of Canarium indicum nuts

As part of a feasibility study of the commercialization potential of C. indicum nuts as Agroforestry Tree Products in Papua New Guinea, preliminary characterization studies have examined the tree-to-tree variation in morphological traits (nut and kernel mass and kernel:nut ratio), as well as nutritional (carbohydrate, fat, protein, sodium, vitamin E) and medicinal traits (anti-oxidant activity, anti-inflammatory activity and phenolic content) of kernels from 18 to 72 trees in a small number of different villages of Papua New Guinea (East New Britain Province). There was continuous variation in these traits indicating opportunities for multiple trait cultivar development targeted at food and pharmaceutical markets. Certain traits, for example anti-inflammatory activity, in which tree-to-tree variation was highly significant, present greater opportunities than others, such as saturated:unsaturated fatty acid ratio. This intraspecific variation was greater within populations than between populations. The data presented has allowed the development of a strategy to domesticate C. indicum for cultivation in homegardens and cocoa-coconut agroforests, using a participatory approach aimed at the production of agroforestry tree products (AFTPs) to empower small-holders and enhance their livelihoods and income.

Using morphological traits to identify persistent lucernes for dryland agriculture in NSW, Australia

This paper reports on several studies conducted to better understand the variability between lucerne cultivars and lines, and use this to predict persistence in dryland grazing pastures in eastern Australia. Morphological traits of 20 cultivars/lines were measured in irrigated and dryland spaced plant experiments. Studies were also conducted to describe variation among lucernes in their utilisation of starch and responses to water deficit, pests and diseases. Multiple regression analyses were used to develop simple models where the measured traits could be used to predict persistence of lucerne lines in dryland evaluation experiments. Although there was significant variation among cultivars/lines in most measured traits, no single trait reliably predicted persistence of cultivars/lines in dryland evaluation experiments. However, variation in persistence at both sites could be explained by models developed by multiple regression using differences in the mean lengths of the longest stems at 10% flower in summer and winter. Persistent lucernes were those that had relatively long stems in summer and short stems in winter. Water use efficiencies, starch utilisation patterns and resistances to pests and diseases of different lucernes provided some improvement to this simple model, but these improvements were not consistent.

DNA markers linked to yield, yield components, and morphological traits in autotetraploid lucerne (Medicago sativa L.)

We have mapped and identified DNA markers linked to morphology, yield, and yield components of lucerne, using a backcross population derived from winter-active parents. The high-yielding and recurrent parent, D, produced individual markers that accounted for up to 18% of total yield over 6 harvests, at Gatton, south-eastern Queensland. The same marker, AC/TT8, was consistently identified at each individual harvest, and in individual harvests accounted for up to 26% of the phenotypic variation for yield. This marker was located in linkage group 2 of the D map, and several other markers positively associated with yield were consistently identified in this linkage group. Similarly, markers negatively associated with yield were consistently identified in the W116 map, W116 being the low-yielding parent. Highly significant positive correlations were observed between total yield and yield for harvests 1-6, and between total yield and stem length, tiller number, leaf yield/plant, leaf yield/5 stems, stem yield/plant, and stem yield/5 stems. Highly significant QTL were located for all these characters as well as for leaf shape and pubescence.

Morphological and developmental comparisons of seven greens quality hybrid bermudagrass (Cynodon dactylon (L.)Pers.x C transvaalensis Burtt-Davy

Fine-textured hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] cultivars have been widely used for golf putting greens and lawn bowls greens in warm-climate areas for more than 40 years. During the past decade, the choice of cultivar for professional turfgrass managers has been expanded by a range of secondgeneration hybrid bermudagrasses, which differ from the first-generation cultivars ‘Tifgreen’ and ‘Tifdwarf ’ in their management requirements. In this paper, we present comparative morphological and developmental data for seven cultivars (Champion Dwarf, FloraDwarf, MS-Supreme, Novotek, Tifdwarf, TifEagle, Tifgreen) grown in spaced plant and sward experiments at Cleveland, Australia (27º32’S lat, 153º15’E long, 25 masl). The four ‘ultradwarf ’ cultivars (Champion Dwarf, MS-Supreme, FloraDwarf, TifEagle) showed slower vertical extension and produced fewer inflorescences than Tifdwarf, Tifgreen, and Novotek. However, in terms of the length of stolon internodes and their overall rate of lateral spread, Champion Dwarf, FloraDwarf, and TifEagle were comparable to Tifdwarf; MS-Supreme (with longer internodes) spread faster laterally, though slower than Tifgreen (which had the longest stolon internodes). In unmown swards, the four ultradwarfs produced shorter leaves than Tifgreen, Tifdwarf, and Novotek, but only Champion Dwarf produced significantly narrower leaves than Tifgreen, Tifdwarf, and Novotek, with TifEagle leaves also significantly narrower than those of Tifgreen and Novotek. Minimum threshold temperatures for growth were approximately 9° to 10°C (air temperature) and 15° to 16°C at 10 cm soil depth.

Stock structure of exploited shark species in north-eastern Australia

The project has provided management and other stakeholders with information necessary to make informed decisions about the management of four of the key exploited shark species caught in the Queensland inshore net fishery and northern New South Wales line fishery. The project has determined that spatial management of milk sharks within Queensland, and scalloped hammerhead, common black tip and Australian black tip sharks within Queensland and New South Wales is appropriate. The project has determined that both black tip shark species are likely to require co-operative management arrangements between Queensland and New South Wales. For scalloped hammerheads separate stocks between the two jurisdictions were identified from the fisheriesdependent samples, however genetic exchange across borders is likely to be facilitated by movement of adult females and perhaps larger males to a lesser extent. This information will greatly assist compliance with the Commonwealth Environment Protection and Biodiversity Conservation Act (1999) for shark fisheries in north-eastern Australia by providing the necessary basis for robust assessment of the status of stocks of the study species, thereby helping to deliver their sustainable harvest. It also helps to achieve objectives of the Australian National Shark Plan. The project provides the appropriate spatial framework for future monitoring and assessment of the study species. This is at a time when shark fisheries are receiving close attention from all sectors and when monitoring programs are being implemented, aimed at better assessment of stock status. This project has provided the crucial information for developing an appropriate monitoring design as well as the necessary basis for making statements about stock status. The project has addressed research priorities identified by the Queensland Fisheries Research Advisory Board, Great Barrier Reef Marine Park Authority and Queensland Fisheries. Previously management has assumed a single stock for each species on the east coast of Queensland, and management of shark fisheries in New South Wales (NSW) and Queensland has been independent of one another. The project has been able to enhance and develop links between research, management and industry. Strong positive relationships with commercial fishers were crucial in the collection of samples throughout the study area and fisheries managers were part of the project team throughout the study period. During the project the study area was extended to include both Queensland and NSW waters, creating mutualistic and positive links between the States’ research and management agencies. Extension of project results included management representatives from NSW and Queensland, as well as the Northern Territory where similar shark fisheries operate and similar species are targeted. The project was able to provide significant human capital development opportunities providing considerable value to the project outcomes. Use of vertebral microchemistry and life history characteristics as stock determination methods provided material for two PhD students based at James Cook University: Ron Schroeder, vertebral chemistry; and Alastair Harry, life history characteristic. The project has developed novel research methods that have great capacity for future application, including: • Development of a simple and rapid genetic diagnostic tool (RT-HRM-PCR assay) for differentiating among the black tip shark species, for which no simple morphological identifier exists; and • Development of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) methods for analysing and interpreting microchemical composition of shark vertebrae. The study has provided further confirmation of the effectiveness of using a holistic approach in stock structure studies and justifies investment into such studies.

Fishing power and standardised catch rates: Implications of missing vessel-characteristic data from the Australian eastern king prawn fishery

Standardised time series of fishery catch rates require collations of fishing power data on vessel characteristics. Linear mixed models were used to quantify fishing power trends and study the effect of missing data encountered when relying on commercial logbooks. For this, Australian eastern king prawn (Melicertus plebejus) harvests were analysed with historical (from vessel surveys) and current (from commercial logbooks) vessel data. Between 1989 and 2010, fishing power increased up to 76%. To date, both forward-filling and, alternatively, omitting records with missing vessel information from commercial logbooks produce broadly similar fishing power increases and standardised catch rates, due to the strong influence of years with complete vessel data (16 out of 23 years of data). However, if gaps in vessel information had not originated randomly and skippers from the most efficient vessels were the most diligent at filling in logbooks, considerable errors would be introduced. Also, the buffering effect of complete years would be short lived as years with missing data accumulate. Given ongoing changes in fleet profile with high-catching vessels fishing proportionately more of the fleet’s effort, compliance with logbook completion, or alternatively ongoing vessel gear surveys, is required for generating accurate estimates of fishing power and standardised catch rates.

Morphological diversity of ruminal bacteriophages from sheep and cattle

Large numbers of bacteriophages (2 x 10(7) to 1 x 10(8)/ml) were present in ruminal fluid from sheep and cattle. Twenty-six distinct types were identified and placed in three morphological groups; several phages possessed unusual structural features. The large numbers and diversity of phages observed indicates a possible role in bacterial lysis and hence in the population dynamics of the ruminal bacteria.

Morphological and molecular diversity of Colletotrichum spp. causing pepper spot and anthracnose of lychee (Litchi chinensis) in Australia

Since the 1980s a new disease has been affecting Australian lychee. Pepper spot appears as small, black superficial lesions on fruit, leaves, petioles and pedicels and is caused by Colletotrichum gloeosporioides, the same fungus that causes postharvest anthracnose of lychee fruit. The aim of this study was to determine if a new genotype of C.gloeosporioides is responsible for the pepper spot symptom. Morphological assessments, arbitrarily-primed PCR (ap-PCR) and DNA sequencing studies did not differentiate isolates of C.gloeosporioides from anthracnose and pepper spot lesions. The ap-PCR identified 21 different genotypes of C.gloeosporioides, three of which were predominant. A specific genotype identified using ap-PCR was associated with the production of the teleomorph in culture. Analysis of sequence data of ITS and -tubulin regions of representative isolates did not group the lychee isolates into a monophyletic clade; however, given the majority of the isolates were from one of three genotypes found using ap-PCR, the possibility of a lychee specific group of C.gloeosporioides is discussed.

Genetic Diversity and Adaptation of Date Palm (Phoenix dactylifera L.)

Acquiring sufficient information on the genetic variation, genetic differentiation, and the ecological and genetic relationships among individuals and populations are essential for establishing guidelines on conservation and utilization of the genetic resources of a species, and more particularly when biotic and abiotic stresses are considered. The aim of this study was to assess the extent and pattern of genetic variation in date palm (Phoenix dacttylifera L) cultivars; the genetic diversity and structure in its populations occurring over geographical ranges; the variation in economically and botanically important traits of it and the variation in its drought adaptive traits, in conservation and utilization context. In this study, the genetic diversity and relationships among selected cultivars from Sudan and Morocco were assessed using microsatellite markers. Microsatellite markers were also used to investigate the genetic diversity within and among populations collected from different geographic locations in Sudan. In a separate investigation, fruits of cultivars selected from Sudan, involved morphological and chemical characterization, and morphological and DNA polymorphism of the mother trees were also investigated. Morphological and photosynthetic adjustments to water stress were studied in the five most important date palm cultivars in Sudan, namely, Gondaila, Barakawi, Bitamoda, Khateeb and Laggai; and the mechanism enhancing photosynthetic gas exchange in date palm under water stress was also investigated. Results showed a significant (p < 0.001, t-test) differentiation between Sudan and Morocco groups of cultivars. However, the major feature of all tested cultivars was the complete lack of clustering and the absence of cultivars representing specific clones. The results indicated high genetic as well as compositional and morphological diversity among cultivars; while, compositional and morphological traits were found to be characteristic features that strongly differentiate cultivars as well as phenotypes. High genetic diversity was observed also in different populations. Slight but significant (p < 0.01, AMOVA) divergence was observed for soft and dry types; however, the genetic divergence among populations was relatively weak. The results showed a complex genetic relationships between some of the tested populations especially when isolation by distance was considered. The results of the study also revealed that date palm cultivars and phenotypes possess specific direct or interaction effects due to water availability on a range of morphological and physiological traits. Soft and dry phenotypes responded differently to different levels of water stress, while the dry phenotype was more sensitive and conservative. The results indicated that date palm has high fixation capacity to photosynthetic CO2 supply with interaction effect to water availability, which can be considered as advantageous when coping with stresses that may arise with climate change. In conclusion, although a large amount of diversity exists among date palm germplasm, the findings in this study show that the role of biological nature of the tree, isolation by distance and environmental effects on structuring date palm genome was highly influenced by human impacts. Identity of date palm cultivars as developed and manipulated by date palm growers, in the absence of scientific breeding programmes, may continue to mainly depend on tree morphology and fruit characters. The pattern of genetic differentiation may cover specific morphological and physiological traits that contribute to adaptive mechanisms in each phenotype. These traits can be considered for further studies related to drought adaptation in date palm.

Effect of Load on Dry Sliding Wear of Aluminum-Silicon Alloys

Aluminum-silicon alloy pins were slid against steel disks under nominally dry condition at a speed of 0.6 m s-1. Each pin was slid at a constant load for 5 min, the load being increased in suitable steps from 2 to 65 N. The results show the wear to increase almost monotonically with load, to be sensitive to the presence of silicon in the alloy, and to be insensitive to actual silicon content. The monotonic nature of wear rate-load characteristic suggests that one dominant wear mechanism prevails over the load range studied. Morphological studies of the pin surface and the debris support this contention and point to delamination as being the dominant mode of wear.

The truncated dielectric-coated conducting sphere-radiation and gain characteristic

An exhaustive study of the radiation and gain characteristics of a truncated dielectric-coated conducting spherical antenna excited in the symmetric TM mode has been reported. The effect of the various structure parameters on the radiation and the gain characteristics for a few even and odd order TM., modes for different structures is shown. The theorctical radiation patterns and gain have been compared with experiment. It is found that there is good agreement between theory and experiment in the case of TM es and TM os,modes. A theoretical and experimental study of the radiation and gain characcteristics in the frequency range 8.0 to 12.0 GHz has been reported.