546 research outputs found
Has the Invisible Hand Shaped a Wooden Spoon? IT Policy in New Zealand
For the past decade and a half New Zealand has been the test-bed of public policies characterized by sustained adherence to theory informed market-based public sector reform. As the title indicates, this article concentrates on the question of how well the policy of market reliance has served New Zealand specifically in the area of Information Technology (I.T.). Arguably, I.T. warrants special attention as a potent factor in all aspects of economic and social life, and a critical component of effective public sector governance and control
A morphological study of the oral cavity, pharyngeal cavity and oesophagus of the Nile crocodile, Crocodylus Niloticus (Laurenti, 1768)
In view of the paucity of detailed information in the literature relevant to the upper digestive tract of the Nile crocodile, this study describes the morphological and histological features of the oral cavity (gingivae, palate and tongue), pharyngeal cavity and oesophagus of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768) using light microscopy. The findings, which were supplemented by scanning electron microscopy, were compared with published information. The ciliated component of the oesophagus was also examined using transmission electron microscopy. The oral cavity had the form of a triangle and was dorso-ventrally flattened. The dorsal limit was formed by the palate and the ventral limit by the broad-based tongue. The close proximity of the tongue and palate severely limited the space within the cavity. The caudal border of the cavity was formed by the dorsal and ventral components of the gular valve. The epithelium of the palate, gingivae and tongue was stratified squamous in nature and appeared lightly keratinised. Specialised epithelial structures in the palate, gingivae and tongue, revealed by both light microscopy (LM) and scanning electron microscopy (SEM), bore characteristics resembling structures responsible for pressure and taste reception. Glandular tissue in the tongue was arranged in a triangular formation in the posterior region and displayed morphological features ascribed to salt secreting glands described in other Crocodilia. There were no palatine glands in the oral region of the palate, except that the oral surface of the dorsal gular fold contained branched tubular mucus secreting glands. The pharyngeal cavity was also dorso-ventrally flattened and was bordered rostrally by the flaccid dorsal gular fold, which displayed a median apical notch, and the ventral gular fold, which was supported internally by the broad rostral tip of the basihyal plate (hyaline cartilage). In the occluded mouth, the dorsal gular fold and the more rostrally positioned ventral component of the gular valve isolated the pharyngeal cavity. This arrangement is essential in preventing the crocodile from drowning (flooding of the pharyngeal cavity) while capturing prey. The roof of the pharyngeal cavity was characterised by the opening to the internal nares (an extension of the nasal passage from the external nares), the fibrous Eustachian plug sealing the common opening to the paired Eustachian ducts and a nodular tonsillar region, which was situated caudo-laterally to the Eustachian plug. Throughout this region, the epithelium was typically ciliated with goblet cells. However, the tonsillar nodules displayed regions of partial or no ciliation on their surface. SEM and stereomicroscopic observations showed fine longitudinal mucosal folding throughout the pharynx the distension of which, together with the large capacity for mucus production (produced by intraepithelial glands and mucus secreting glands), would facilitate the swallowing of large chunks of food in the living state. The ventrally situated laryngeal mound containing the slit-like glottis also displayed longitudinal folds and a ciliated epithelium. Anatomically, the oesophagus could be divided into two clear regions. The cranial, approximate two-thirds appeared broad and flabby. At the tracheal bifurcation, the oesophagus narrowed significantly and indicated a greater muscular content, confirmed by light microscopy. LM and SEM examination of the oesophagus, however, revealed three regional components, viz., the cranial, mid- and caudal regions. In the cranial region, the epithelium was densely ciliated with intervening goblet cells being present. In the mid-region the ciliated component decreased with a concomitant increase in the goblet cell component. In the caudal region there was a further decrease in the number of ciliated cells and a higher concentration of goblet cells. Transmission electron microscopy (TEM) of the ciliated component of the oesophagus showed typical ultrastructural features of both the ciliated and goblet cells.Dissertation (MSc (Veterinary Science))--University of Pretoria, 2002.Anatomy and Physiologyunrestricte
The CONSTANS gene of arabidopsis promotes flowering and encodes a protein showing similarities to zinc finger transcription factors
AbstractThe vegetative and reproductive (flowering) phases of Arabidopsis development are clearly separated. The onset of flowering is promoted by long photoperiods, but the constans (co) mutant flowers later than wild type under these conditions. The CO gene was isolated, and two zinc fingers that show a similar spacing of cysteines, but little direct homology, to members of the GATA1 family were identified in the amino acid sequence. co mutations were shown to affect amino acids that are conserved in both fingers. Some transgenic plants containing extra copies of CO flowered earlier than wild type, suggesting that CO activity is limiting on flowering time. Double mutants were constructed containing co and mutations affecting gibberellic acid responses, meristem identity, or phytochrome function, and their phenotypes suggested a model for the role of CO in promoting flowering
Towards Understanding Photoperiodic Response in Grasses
In many plants, day length is the critical environmental parameter that controls flowering time. In long day plants, such as Arabidopsis and ryegrass (Lolium perenne), increasing day length in spring signals flowering, while in short day plants like rice, flowering is accelerated when days become shorter. Recently, significant progress has been made in understanding the molecular genetic mechanisms that govern this response. Most results have been obtained in the model plant Arabidopsis where CONSTANS (CO) is a critical candidate gene. Upstream of it is the GIGANTEA (GI) gene which is associated with the circadian clock mechanism (1). The FT gene is the immediate downstream genetic target of CO, and is a direct promoter of flowering (2). Characteristically, all three genes show circadian expression, albeit in different phases, and both the CO and FT genes are up-regulated under long-day (inductive) conditions. Work in ryegrass should help reveal both the conserved and divergent segments of the photoperiod response between different plant species
Month by month overview of UWE Bristol's Green Capital year
The document provides a month-by-month summary of activities which were undertaken by UWE staff and students in support of Bristol's year as European Green Capital. More detail on these activities can be found in the UWE Green Capital Activities Catalogue and accompanying Portfolio
Developing a method for customized induction of flowering
<p>Abstract</p> <p>Background</p> <p>The ability to induce flowering on demand is of significant biotechnological interest. FT protein has been recently identified as an important component of the mobile flowering hormone, florigen, whose function is conserved across the plant kingdom. We therefore focused on manipulation of both endogenous and heterologous <it>FT </it>genes to develop a floral induction system where flowering would be inhibited until it was induced on demand. The concept was tested in the model plant <it>Arabidopsis thaliana </it>(Arabidopsis).</p> <p>Results</p> <p>Our starting point was plants with strongly delayed flowering due to silencing of <it>FT </it>with an artificial microRNA directed at <it>FT </it>(<it>amiR-FT</it>) <abbrgrp><abbr bid="B1">1</abbr></abbrgrp>. First, we showed that constitutive expression of a heterologous <it>FT </it>gene (<it>FTa1</it>), from the model legume <it>Medicago truncatula</it>, (Medicago) was able to rescue the <it>amiR-FT </it>late-flowering phenotype. In order to induce flowering in a controlled way, the <it>FTa1 </it>gene was then expressed under the control of an alcohol-inducible promoter in the late flowering <it>amiR-FT </it>plants. Upon exposure to ethanol, <it>FTa1 </it>was rapidly up regulated and this resulted in the synchronous induction of flowering.</p> <p>Conclusions</p> <p>We have thus demonstrated a controlled-inducible flowering system using a novel combination of endogenous and heterologous <it>FT </it>genes. The universal florigenic nature of FT suggests that this type of system should be applicable to crops of economic value where flowering control is desirable.</p
The transcriptomic response to a short day to long day shift in leaves of the reference legume Medicago truncatula
Photoperiodic flowering aligns plant reproduction to favourable seasons of the year to maximise successful production of seeds and grains. However understanding of this process in the temperate legumes of the Fabaceae family, which are important both agriculturally and ecologically, is incomplete. Previous work in the reference legume Medicago truncatula has shown that the FT-like gene MtFTa1 is a potent floral activator. While MtFTa1 is upregulated by long-day photoperiods (LD) and vernalisation, the molecular basis of this is unknown as functional homologues of key regulatory genes present in other species, notably CONSTANS in A. thaliana, have not been identified. In LD MtFTa1 maintains a near constant diurnal pattern of expression unlike its homologue FT in A. thaliana, which has a notable peak in expression at dusk. This suggests a different manner of regulation. Furthermore, M. truncatula possesses other FT-like genes such as two LD induced MtFTb genes which may also act in the regulation of flowering time. MtFTb genes have a diurnal pattern of expression with peaks at both four and sixteen hours after dawn. This study utilises RNA-Seq to analyse the transcriptome of M. truncatula leaves to identify genes which may regulate or be co-expressed with these FT-like genes following a shift from short-day photoperiods to inductive long-days. Specifically this study focuses on the first four hours of the day in the young leaves, which coincides with the first diurnal peak of the FTb genes. Following differential expression analysis at each timepoint, genes which alter their pattern of expression are distinguished from those which just alter their magnitude of expression (and those that do neither). It goes on to categorise these genes into groups with similar patterns of expression using c-means clustering and identifies a number of potential candidate photoperiod flowering time genes for future studies to consider
Oribatid mites (Acari, Oribatida) as intermediate hosts of tapeworms of the Family Anoplocephalidae (Cestoda) and the transmission of Moniezia expansa cysticercoids in South Africa
Six species of adult oribatid mites (Galumna racilis, Kilimabates pilosus, Kilimabates sp., Scheloribates
fusifer, Muliercula ngoyensis and Zygoribatula undulata) and two immature stages belonging to
the superfamilies Galumnoidea and Ceratozetoidea were isolated from a
lawn (mixed Pennisetum and Cynodon spp.) at Onderstepoort Veterinary Institute, South
Africa. The mites were subsequently used in an infection trial using
Moniezia expansa eggs. Tapeworm cysticercoids were recovered in G. racilis,
K. pilosus, Kilimabates sp., S. fusifer, M. ngoyensis and Z. undulata, as well as in immatures of Ceratozetoidea. The percentage
of infected mites was 7.6, 6.3, 16.4, 66.7, 57.1, 60.0 and 46.7%,
respectively. Immatures of Galumnoidea did not become infected. The highest
number of cysticercoids isolated from one individual was six from an adult S. fusifer.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.F. Kleine Bursary of the Onderstepoort Veterinary Institute.mn201
Studies on the genus Setaria Viborg, 1795 in South Africa. I. Setaria africana (Yeh, 1959)
Setaria africana (Yeh, 1959) is represented by two subspecies, Setaria africana africana Troncy, Graber & Thal, 1976 from giant eland (Taurotragus derbianus) from the Central African Republic and Cameroon and Setaria africana farchai Troncy, Graber & Thal, 1976 from bush buck ( Tragelaphus scriptus), also from the Central African Republic. Material collected from nyala (Tragelaphus angasii), bushbuck and kudu (Tragelaphus strepsiceros) from several localities in the eastern region of South Africa was reexamined. Measurements of adult worms confirmed the differences between the two subspecies and scanning electron microscopy showed that the deirids of S. africana africana are single whereas those of S. africana farchai are double. Setaria africana farchai is recorded for the first time in South Africa.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat v.9 was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.mn201
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