601 research outputs found
Bryophytes and their distribution in the Blue Mountains region of New South Wales
The bryophytes (mosses, liverworts and hornworts) that occur in the Blue Mountains region of New South Wales (latitude 33˚–34˚ S, longitude 151˚–151˚40’ E) are listed and information is provided on their distribution in the region. Species lists are based on herbarium specimens and field collections. 348 bryophyte taxa have been recorded from 70 families, including 225 moss taxa (in 108 genera from 45 families), 120 liverwort taxa (in 51 genera from 24 families) and 3 hornwort taxa (in 3 genera from one family). The moss families with most taxa are the Pottiaceae (with 23 taxa in 13 genera), Bryaceae (with 15 taxa in 3 genera) and Fissidentaceae (with 13 taxa). The largest genera are Fissidens (13 taxa), Campylopus (9) and Macromitrium (8). The liverwort family with the most taxa is Lepidoziaceae, with 29 taxa in 10 genera. The largest liverwort genera are Frullania (11 taxa) and Riccardia (8). The species lists include collections from both bushland and urban areas. Natural features of the Blue Mountains, including topography, altitude, climate and vegetation appear to be important factors influencing the number of bryophyte species recorded from each location. The number of collections from particular locations has been considerably influenced by ease of access, particularly proximity to roads, public transport and railway stations. The species lists include many records from areas that were not accessible to the early collectors of the late 19th and early 20th centuries such as Wollemi National Park, Gardens of Stone National Park, Newnes Plateau and Kanangra-Boyd National Park
Filarial Antigens : Targets For Diagnosis, Protection And Pathology
A range of surface, secreted and somatic antigens from filarial parasites have been studies in order to analyse the response of human infected with these pathogens, and to develop reliable diagnostic and prophylactic agents. Diagnostic procedures, which are urgently required for targetting chemotherapy, are being developed by two techniques. Firstly, detection of host antibody is carried out using selected, specific parasite antigens in the form of recombinant peptides from a filarial DNA library. Secondly, measurement of parasite by a monoclonal antibody "antigen-capture" assay. In addition, a longer-term objective of our collaborative study is to isolate molecules which may stimulate the immune system to mount a protective immune response against filarial parasites. A major focus has been a parasite surface glycoprotein known to be closely conserved between adult worms of Brugia malayi, B. timori and Wuchereria bancrofti. This antigen has been cloned from a cDNA library, and its primary sequence established; in addition to being a constant feature of the adult surface, it is expressed by developing larvae and represents an attractive target for vaccine production. Finally, one of the most intriguing questions in filariasis relates to the genesis of pathological reactions. Although this is a difficult problem, we are now beginning to compare the immune responses of individuals of differing clinical status to certain defined parasite antigens, in an attempt to correlate disease development with particular categories of immune response in infected patients. In this way there is hope to advance the basic understanding of filarial disease, while providing practical means for controlling filariasis at the individual and community levels
The relationship between language production and verbal short-term memory: The role of stress grouping
This study investigates the influence of stress grouping on verbal short-term memory (STM). English speakers show a preference to combine syllables into trochaic groups, both lexically and in continuous speech. In two serial recall experiments, auditory lists of nonsense syllables were presented with either trochaic (STRONG-weak) or iambic (weak-STRONG) stress patterns, or in monotone. The acoustic correlates that carry stress were also manipulated in order to examine the relationship between input and output processes during recall. In Experiment 1, stressed and unstressed syllables differed in intensity and pitch but were matched for spoken duration. Significantly more syllables were recalled in the trochaic stress pattern condition than in the iambic and monotone conditions, which did not differ. In Experiment 2, spoken duration and pitch were manipulated but intensity was held constant. No effects of stress grouping were observed, suggesting that intensity is a critical acoustic factor for trochaic grouping. Acoustic analyses demonstrated that speech output was not identical to the auditory input, but that participants generated correct stress patterns by manipulating acoustic correlates in the same way in both experiments. These data challenge the idea of a language-independent STM store and support the notion of separable phonological input and output processes
Signal sequence analysis of expressed sequence tags from the nematode Nippostrongylus brasiliensis and the evolution of secreted proteins in parasites
BACKGROUND: Parasitism is a highly successful mode of life and one that requires suites of gene adaptations to permit survival within a potentially hostile host. Among such adaptations is the secretion of proteins capable of modifying or manipulating the host environment. Nippostrongylus brasiliensis is a well-studied model nematode parasite of rodents, which secretes products known to modulate host immunity. RESULTS: Taking a genomic approach to characterize potential secreted products, we analyzed expressed sequence tag (EST) sequences for putative amino-terminal secretory signals. We sequenced ESTs from a cDNA library constructed by oligo-capping to select full-length cDNAs, as well as from conventional cDNA libraries. SignalP analysis was applied to predicted open reading frames, to identify potential signal peptides and anchors. Among 1,234 ESTs, 197 (~16%) contain predicted 5' signal sequences, with 176 classified as conventional signal peptides and 21 as signal anchors. ESTs cluster into 742 distinct genes, of which 135 (18%) bear predicted signal-sequence coding regions. Comparisons of clusters with homologs from Caenorhabditis elegans and more distantly related organisms reveal that the majority (65% at P < e(-10)) of signal peptide-bearing sequences from N. brasiliensis show no similarity to previously reported genes, and less than 10% align to conserved genes recorded outside the phylum Nematoda. Of all novel sequences identified, 32% contained predicted signal peptides, whereas this was the case for only 3.4% of conserved genes with sequence homologies beyond the Nematoda. CONCLUSIONS: These results indicate that secreted proteins may be undergoing accelerated evolution, either because of relaxed functional constraints, or in response to stronger selective pressure from host immunity
Vaccination with novel low-molecular weight proteins secreted from Trichinella spiralis inhibits establishment of infection
Trichinella spiralis muscle stage larvae (mL1) produce excretory-secreted products (ESPs), a complex mixture of protein, which are believed to be important for establishing or maintaining an infection niche within skeletal muscle and the intestine. Studies of both whole ESPs and individual cloned proteins have shown that some ESPs are potent immunogens capable of eliciting protective immune responses. Here we describe two novel proteins, Secreted from Muscle stage Larvae SML-4 and SML-5 which are 15 kDa and 12 kDa respectively. The genes encoding these proteins are highly conserved within the Trichinellids, are constituents of mL1 ESP and localized in the parasite stichosome. While SML-5 is only expressed in mL1 and early stages of adult nematode development, SML-4 is a tyvosylated glycoprotein also produced by adult nematodes, indicating it may have a function in the enteral phase of the infection. Vaccination with these proteins resulted in an impaired establishment of adult stages and consequently a reduction in the burden of mL1 in BALB/c mice. This suggests that both proteins may be important for establishment of parasite infection of the intestine and are prophylactic vaccine candidates
Effects of phonological phrasing on syntactic structure
Bantu languages are renowned as tone languages that utilize this suprasegmental feature not only on the lexical level to distinguish lexical items, but also on the grammatical level to distinguish clause types. This article investigates one such use of grammatical tone in relative clauses in Bemba where a low tone can be used in place of a segmental relative marker. This low tone relative morpheme functions in conjunction with phrase boundary tone indicated on the head noun and which entails either restrictive or non-restrictive interpretations of relatives. Considering a mapping of XPs to major phonological phrases in the syntax-prosody interface, the resultant phonological phrasing in relatives influences the choice of syntactic structure. In the case at hand, a head-raising analysis provides an optimal mapping between syntax and prosody for restrictives. Further, a more direct influence of phonology on syntax can be seen in a perception-based model like Dynamic Syntax where the on-line building of syntactic trees can gain import from phonological information. © Walter de Gruyter 2007
A rare presentation of atypical demyelination: tumefactive multiple sclerosis causing Gerstmann's syndrome
r. KS has been supported by a Higher Education Funding Council for
England (HEFCE) Clinical Senior Lectureshi
Acoustic Correlates of Information Structure.
This paper reports three studies aimed at addressing three questions about the acoustic correlates of information structure in English: (1) do speakers mark information structure prosodically, and, to the extent they do; (2) what are the acoustic features associated with different aspects of information structure; and (3) how well can listeners retrieve this information from the signal? The information structure of subject-verb-object sentences was manipulated via the questions preceding those sentences: elements in the target sentences were either focused (i.e., the answer to a wh-question) or given (i.e., mentioned in prior discourse); furthermore, focused elements had either an implicit or an explicit contrast set in the discourse; finally, either only the object was focused (narrow object focus) or the entire event was focused (wide focus). The results across all three experiments demonstrated that people reliably mark (1) focus location (subject, verb, or object) using greater intensity, longer duration, and higher mean and maximum F0, and (2) focus breadth, such that narrow object focus is marked with greater intensity, longer duration, and higher mean and maximum F0 on the object than wide focus. Furthermore, when participants are made aware of prosodic ambiguity present across different information structures, they reliably mark focus type, so that contrastively focused elements are produced with greater intensity, longer duration, and lower mean and maximum F0 than noncontrastively focused elements. In addition to having important theoretical consequences for accounts of semantics and prosody, these experiments demonstrate that linear residualisation successfully removes individual differences in people's productions thereby revealing cross-speaker generalisations. Furthermore, discriminant modelling allows us to objectively determine the acoustic features that underlie meaning differences
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