41 resultados para MORPHOLOGICAL AFFINITIES

em Deakin Research Online - Australia


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The taxonomic uncertainty surrounding several prominent genera of Australian microbat has been a long-standing impediment to research and conservation efforts on these groups. The free-tail bat genus Mormopterus is perhaps the most significant example, with a long history of acknowledged species-level confusion. This study uses a combined molecular and morphological approach to conduct a comprehensive assessment of species and subgeneric boundaries, between-species phylogenetic affinities and within-species phylogeographic structure in Australian members of Mormopterus. Phylogenetic analyses based on 759 base pairs of the NADH Dehydrogenase subunit 2 mitochondrial gene were concordant with species boundaries delineated using an expanded allozyme dataset and by phallic morphology, and also revealed strong phylogeographic structure within two species. The levels of divergence evident in the molecular and morphological analyses led us to recognise three subgenera within Australia: Micronomus, Setirostris subgen. nov. and Ozimops subgen. nov. Within Ozimops we recognise seven Australian species, three of which are new, and none are conspecific with Indo-Papuan species. The family Molossidae now comprises eleven species across three subgenera in Australia, making it the continent's second most speciose family of bats. © CSIRO 2014.

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A moderately diverse Permian brachiopod fauna is described from a new rock unit, the Bera Formation, in the Bera District, central Pahang, Peninsular Malaysia. The fauna consists of 19 taxa, including 14 genera and 17 (both identified and unidentified) typically Tethyan species. The fauna appears to be correlative on the basis of brachiopods with the Neoschwagerina-Yabeina fusulinid Zones in Indochina and South China. In particular, it has strong linkage to Member C (Yabeina beds) of the Sisophon Limestone, west Cambodia. This is indicated by three of the Bera species — Urushtenoidea chaoi (Ching), Spyridiophora gubleri Termier and Termier, and Transennatia termierorum sp. nov., being shared with the Cambodian fauna. A possible early Capitanian (Middle Permian) age is proposed for the Bera brachiopod fauna.

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The terms ‘Leptodus Shales’ and ‘Leptodus Beds’ have been used to describe a rich brachiopod bearing unit within the Permian argillaceous facies of the Central Belt of Peninsular Malaysia. To date there has been no formal description of this unit regarding its age, spatial distribution or faunal composition. A review of previous literature, backed by recently collected data from our field surveys and biostratigraphical studies reveals that there is a sequence of fossiliferous assemblages within the Leptodus Shales, which range in age from Middle Permian to possibly early Late Permian and extend geographically from southern Kelantan to southern Pahang, Peninsular Malaysia. These assemblages are found in argillaceous sediments which are often highly tuffaceous, and in northern Pahang are associated with pyroclastic volcanics of probable island-arc origin. The faunas are of Palaeo-equatorial affinity and are taxonomically close to faunas in Indochina, such as the Sisophon fauna in Cambodia. Typical elements include Vediproductus cf. punctatiformis (Chao), Transennatia gratiosa (Waagen), T. termierorum Sone, Leman and Shi, Uncuninellina timorensis (Beyrich), Leptodus richthofeni Kayser, L. cf. tenuis (Waagen), Leptodus nobilis (Waagen), Gubleria aff. ninglangensis Fang and Jiang, and Spyridiophora gubleri Termier and Termier.

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Morphology has often been used as an indicator of variability within species. The present study investigated morphological and physiological characteristics of isolates of Phytophthora cinnamomi collected from diseased vegetation communities at Anglesea, Victoria, and isolates collected from other regions in the State. Characteristics studied included growth rate on potato-dextrose agar (PDA), corn-meal agar and V8-juice agar at 24°C, growth rate on V8 agar at 15°C, colony morphology on PDA, sporangial and gametangial morphology, sporangial production and mating type. Phenotypic variation was demonstrated in radial growth rate, colony morphology and sporangial dimensions. Sporangial and oogonial dimensions and sporangial production were not significantly different between isolates from different geographical regions. All isolates were found to be of the A2 mating type suggesting variation was derived asexually. Paragynal associations, in an organism characteristically defined as amphigynal, were observed following crossing with A1 isolates. This is the first such study undertaken in southern Victoria. The findings highlight the importance of appropriate management of an area of such high conservation value as the Anglesea Heath to contain the current infection and to prevent introduction of new isolates into the area.

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Adult peregrine falcons (Falco peregrinus macropus) have monotypic plumage and display strong reversed sexual dimorphism, with females significantly larger than males. Reversed sexual dimorphism is measurable among nestlings in the latter stages of their development and can therefore be used to differentiate between sexes. In the early stages of development, however, nestlings cannot be sexed with any degree of certainty because morphological differentiation between the sexes is not well developed. During this study we developed a model for sexing younger nestlings based on genetic analysis and morphometric data collected as part of a long-term banding study of this species. A discriminant function model based on morphological characteristics was developed for determining the sex of nestlings (n = 150) in the field and was shown to be 96.0% accurate. This predictive model was further tested against an independent morphometric dataset taken from a second group of nestlings (n = 131). The model correctly allocated sex to 96.2% of this second group of nestlings. Sex can reliably be determined (98.6% accurate) for nestlings that have a wing length of at least 9 cm using this model. Application of this model, therefore, allows the banding of younger nestlings and, as such, significantly increases the period of time over which banding can occur. Another important implication of this model is that by banding nestlings earlier, they are less likely to jump from the nest, therefore reducing the risk of injury to both the brood and the bander.

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This paper introduces a novel methodology for object detection using genetic algorithms and morphological processing. The method employs a kind of object oriented structuring element, which are derived using genetic algorithm operating. The population of morphological filters iteratively evaluated according to a statistical performance index corresponding to object extraction ability, and evolves into an optimal structuring elements using the evolution principles of genetic search. Experimental results of object extraction in high resolution satellite images are presented to illustrate the merit and feasibility of the proposed method.

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In this study, we aimed to detect morphological and biochemical changes in developing germ cells (Gc), testicular sperm (Tsp), and spawned sperm (Ssp) using capacitation-associated characteristics. Gradual changes in the profiles of two membrane proteins, namely NaCl- and detergent-extractable proteins, were observed as compared Gc with Tsp and Tsp with Ssp. These membrane modifications were accomplished mostly through the introduction of new protein sets, both peripheral and integral, into Tsp and Ssp membranes. Activation of serine proteases, particularly in Ssp detergent-extracted proteins with the molecular masses of 38–130 kDa was evident and marked a major difference between Ssp and Tsp. An increase in the level of tyrosine phosphorylation of the proteins ranging from 15 to 20 kDa was noted in Tsp and remained constant in Ssp. Specifically, these three capacitation-associated characteristics could be detected in Ssp, possessing full fertilizing capacity. The lack of an activated proteolytic activity in Tsp resulted in a delayed fertilization, but not affected fertilizing ability. We believe that these characteristics should be advantageous in predicting abalone sperm fertilizing capability, particularly in cases when isolated germ cells or purified Tsp are used in place of spawned sperm in abalone aquaculture.

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The effects of environmental stress on the physiology and behaviour of higher vertebrates has become an important avenue of research in recent years. Evidence from recent studies has suggested that the avian stress-related hormone corticosterone (CORT) may play a role in immunocompetence and sexual selection. We tested whether CORT is immunosuppressive by studying humoral and cell-mediated immune responses in populations of captive zebra finches selected for divergent peak levels of CORT. We also investigated whether selection for peak CORT has an effect on the quality of several sexually selected regions of the male zebra finch; in addition we compared morphometric parameters and the dominance ranking in males from the different selection lines. We also tested whether different components of the immune system compete for limited resources. We found that selection for divergent levels of peak CORT had little effect on humoral immunity, male sexual signal quality or dominance ranking. However, contrary to expectations, we did find a positive relationship between CORT titre and cell-mediated immunity, as well as a greater cell-mediated response in the birds selected for high CORT titre than those selected for low CORT titre. Consistent with predictions, significant negative relationships were found between both testosterone and CORT titre on humoral immunity. Birds from the low CORT lines were significantly larger in terms of skeletal size than those from the high CORT lines. Overall, our results suggest that the cell-mediated immune response is associated with a reduction in the humoral response, but only in males, and that there is no simple relationship between peak CORT levels and immune function.

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Electrospinning is a very useful technique to produce polymeric nanofibers. It involves fast-drawing a polymer fluid into nanofibers under a strong electric filed, and depositing randomly on an electrode collector to form non-woven nanofiber mat in most cases [1]. The fibre stretching during electrospinning is a fast and incessant process which can be divided into three consecutive stages: jet initiation, whipping instability and fibre deposition. From the initial jet to dry fibres, the fibre stretching takes place in milliseconds, so it has been hardly so far to observe fiber morphology changes by any normal methods, such as high speed photography [2-5]. In this study, we used a facile and practical approach to realize the observation of nanofiber morphology changes during electrospinning. Through a special collection device with coagulation bath, newly electrospun nanofibers can be solidified at different electro spinning distances, and by associating the fiber morphology with the electrospinning distance (d), the morphological evolution of nanofibers can be established. We used polyacrylonitrile (PAN) and polystyrene (PS) as two model polymers to demonstrate this method in present research. From experimental results, we found the massive jet-thinning happens at the initial stage of the process. The formation of uniform PAN nanofibers (7%) and the beads structure changes on beads-on-string PAN nanofibers (5%) have also been successful observed. Using the same method, we also observed PS nanofiber (10%) morphology changes to understand the beads formation 011 nanofibers during electrospinning process, and how the beads was eliminated when ionic surfactant is added into the PS solution for electrospinning.

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The Spotted Bowerbird, Chlamydera maculata, appears to be sexually monomorphic. We caught and marked 118 birds in central Queensland, and sexed 88 using molecular methods. We found that our catch was strongly male-biased, both at bower sites and at non-bower feeding sites. We continued to observe the bird's behaviour after their release and so sub-divided males into sexual status groups as either bower-owners or non-owners. We searched for morphological measures, subjectively judged colour differences and quantitatively collected spectral measures of the visual properties of the crest feathers that would allow us to separate birds of differing sex and status. We found that bower owners had larger crests than non-owner males or females and that crest area provided the most accurate predictor of a bird's sex and status in a discriminant function analysis. We studied a cohort of seven males who went from non-owners to bower owners over three years, and found that their change in status was accompanied by a change in crest size – the only significant change in their morphology. Crest size did not relate to the mating success of a bower-owner. Instead, we suggest why the crest may differ between status groups and the implications that this may have for the sexual behaviour of male and female Spotted Bowerbirds.

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Seventeen primary school deaf and hard-of-hearing children were given two types of training for 9 weeks each. Phonological training involved practice of /s, z, t, d/ in word final position in monomorphemic words. Morphological training involved learning and practicing the rules for forming third-person singular, present tense, past tense, and plurals. The words used in the two training types were different (monomorphemic or polymorphemic) but both involved word final /s, z, t, d/. Grammatical judgments were tested before and after training using short sentences that were read aloud by the child (or by the presenter if the child was unable to read them). Perception was tested with 150 key words in sentences using the trained morphemes and phonemes in word final position. Grammatical judgments for sentences involving the trained morphemes improved significantly after each type of training. Both types of training needed to be completed before a significant improvement was found for speech perception scores. The results suggest that both phonological and morphological training are beneficial in improving speech perception and grammatical performance of deaf and hard-of-hearing children and that both types of training were required to obtain the maximum benefit.