284 research outputs found
Irritation cancer: its bearings on the cancer problem as shown by Kangri Epithelioma
A. Ephilis ab igne is associated with:
1. Increased pigmentation.
2. Overgrowth of the palisade layer
of epithelial cells.
3. Down growth of the papillae into
the rete malpigii.
4. The areas most intensely affected
hear a striking resemblance to the
areas of superficial nerve distributionB. Kangri burn epithelioma:
1. Is frequently secondary to horny
growth.
2. The horns are composed of layers of
squamous epithelial cells, being an
exaggeration of the normal horny production
on the hand.
3. The points of cancer incidence correspond
to the edges of the ephilis
ab igne patches.
4. That the incidence of cancer at once
stops all the chemical changes by
which the protoplasm of the squamous
epithelial cells is changed into
eleidin and kerato-hyaline.
5. That cauliflower epithelioma with
horny growths i s more common in
Kashmir than in Britain.
6. That several points in the history,
incidence and growth of this cancer,
point to a nervous origin of the
growth, either disease, or insufficient
control, and give fruit for
thought and require further investigation
Soft-tissue specimens from pre-European extinct birds of New Zealand
We provide the first complete review of soft tissue remains from New Zealand birds that became extinct prior to European settlement (c. AD 1800). These rare specimens allow insights into the anatomy and appearance of the birds that are not attainable from bones. Our review includes previously unpublished records of ‘lost’ specimens, and descriptions of recently discovered specimens such as the first evidence of soft tissues from the South Island goose (Cnemiornis calcitrans). Overall, the soft tissue remains are dominated by moa (with specimens from each of the six genera), but also include specimens from Finsch's duck (Chenonetta finschi) and the New Zealand owlet-nightjar (Aegotheles novaezealandiae). All desiccated soft tissue specimens that have radiocarbon or stratigraphic dates are late Holocene in age, and most have been found in the semi-arid region of Central Otago
High-resolution coproecology: Using coprolites to reconstruct the habits and habitats of New Zealand’s extinct upland Moa (Megalapteryx didinus)
Knowledge about the diet and ecology of extinct herbivores has important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes. The flightless ratite moa (Aves: Dinornithiformes) were New Zealand's largest herbivores prior to their extinction soon after initial human settlement. Here we contribute to the knowledge of moa diet and ecology by reporting the results of a multidisciplinary study of 35 coprolites from a subalpine cave (Euphrates Cave) on the South Island of New Zealand. Ancient DNA analysis and radiocarbon dating revealed the coprolites were deposited by the extinct upland moa (Megalapteryx didinus), and span from at least 6,368±31 until 694±30 ¹⁴C years BP; the approximate time of their extinction. Using pollen, plant macrofossil, and ancient DNA analyses, we identified at least 67 plant taxa from the coprolites, including the first evidence that moa fed on the nectar-rich flowers of New Zealand flax (Phormium) and tree fuchsia (Fuchsia excorticata). The plant assemblage from the coprolites reflects a highly-generalist feeding ecology for upland moa, including browsing and grazing across the full range of locally available habitats (spanning southern beech (Nothofagus) forest to tussock (Chionochloa) grassland). Intact seeds in the coprolites indicate that upland moa may have been important dispersal agents for several plant taxa. Plant taxa with putative anti-browse adaptations were also identified in the coprolites. Clusters of coprolites (based on pollen assemblages, moa haplotypes, and radiocarbon dates), probably reflect specimens deposited at the same time by individual birds, and reveal the necessity of suitably large sample sizes in coprolite studies to overcome potential biases in diet interpretation
Evaluating the character and preservation of DNA within allophane clusters in buried soils on Holocene tephras, northern New Zealand
Clay minerals possess sorptive capacities for organic and inorganic matter, including DNA (Lorenz and Wackernagel, 1994), and hence reduce the utilization and degradation of organic matter or DNA by microorganisms. Buried allophane-rich soils on tephras (volcanic-ash beds) on the North Island, dated using tephrochronology, provide a valuable paleobiological ‘laboratory’ for studying the preservation of ancient DNA (aDNA) (Haile et al., 2007). Allophane comprises Al-rich nanocrystalline spherules ~3.5-5 nm in diameter (Fig. 1) with extremely large surface areas (up to 1000 m2 g-1). Moreover, allophanic soils are strongly associated with organic matter (Parfitt, 2009), and so we hypothesize that allophane also plays an important role for DNA protection within such soils
Integrating transaction cost and institutional theories in an emerging market context: the case of the Tiger Leaping Gorge, Southwest China
The aim of this thesis is to explore the applicability of transaction cost theory to an
emerging market context, and to complement it with institutional theory to achieve a
closer fit. The research questions are:
(1) Which causes of high transaction costs are perceived by firms in the research
site?
(2) How do they respond to these costs? The responses could range from
internalisation, through cooperation, to the new concept of trading isolation,
which is the first of two observed gaps in the literature.
(3) Could an institutional perspective help to explain firms’ responses, if they differ
from what is expected by theory? The consideration of informal institutions with
regard to transaction costs in China addresses the second observed gap in the
literature, which focuses mostly on formal institutions.
Despite the strengths of transaction cost theory in identifying sources of friction in
exchange and proposing resolutions, it has been criticised for making assumptions
concerning behaviour and the strength of formal institutions that reduce the degree to
which it applies in non-Western, emerging market research contexts. This thesis
explores these limitations in the context of the inbound tourism sector in the Tiger
Leaping Gorge, in rural Yunnan Province, Southwest China. The author’s
exploratory study had suggested that some of these firms attempted to reduce
transaction costs by decreasing the number of transactions conducted, resulting in
their relative isolation from – rather than integration into – a trading network. This
hinders the firms’ ability to develop and specialise, limiting their contribution to
local economic growth in this relatively undeveloped region of China.
In the principal field study, qualitative data were collected through interviews
conducted with the proprietors of the population of tourism firms in the research site. The interviews sought to understand the transaction costs the proprietors perceived,
their views of institutional strength or weakness (in areas including local
government, legal system, financing, development of trust, kinship, guanxi and
networks), and the ways they organised their firms. The data were explored first with
a thematic analysis, then by coding into fuzzy sets for analysis with the Qualitative
Comparative Approach to help identify causal associations between transaction
costs, institutions, and responses of isolation from or integration into the market.
The main causes of transaction costs were found to be opportunism, uncertainty and
bounded rationality. High transaction costs were generally associated with a response
of isolation, but they were not the sole causal factor: every isolated firm reported
weak informal institutions combined with a variety of transaction cost and formal
institutional conditions. The difficulty of establishing new trust relationships
increased the isolation of the worst-affected firms, in an environment where weak
formal protection from transaction risks confined many firms to personal exchange.
A recommendation for local practice is made for firms to attempt to broaden the
networks within which they develop trust, to reduce the constraint of personal
exchange and consequent isolation. Two policy recommendations are made that
could apply here and in emerging markets more generally: a mainstream
recommendation to strengthen the enforcement of formal institutions, aiming to
facilitate rule-based, impersonal exchange based on generalised trust, and an
alternative approach deriving recommendations from the local context and including
the consideration of informal institutions.
This thesis contributes to theory by highlighting the critical influence of informal
social structures on the cost and extent of exchange, and adapting transaction cost
theory to better apply to this institutional context. It also constitutes a novel
application of the Qualitative Comparative Approach to interview data
Studies in the life history and taxonomy of the genus Enteromorpha
The genus Enteromorpha is usually placed in the family Ulvaceae (Bliding, 1963; Taylor, 1937, 1960; Chapman, 1956). This family includes those green algae with flat or tubular thalli, and cells with one or two lateral chromatophores and a single pyrenoid. The asexual spore-producing and sexual gamete-producing generations are morphologically identical (Bliding, 1963 P.41).
Enteromorpha includes the branched or unbranched monostromatic members of the Ulvaceae which are hollow and tubular.
A variety of life histories have been described for the Genus. These include monomorphic diplontic - Enteromorpha intestinalis var asexualis (Bliding, 1963), Enteromorpha biflagellata (Bliding, 1944); Monomorphic diplohaplontic - several species including Enteromorpha ramulosa (Hartmann, 1929), Enteromorpha intestinalis (Kylin, 1930 a.; Eliding, 1948 a.); Monomorphic haplontic Enteromorpha stipitata P. Dangeard var linzoides nov. var. (Bliding, 1960).
No dimorphic diplohaplontic life histories have as yet been described for any member of the Ulvaceae. There have, however, been indications of their existence in some genera.
Pocock (1961) investigated this possibility in Letterstedtia. Chapman (1956) discussed the possible alternation of a branched and unbranched generation in Enteromorpha australiensis unsupported to date by experimental evidence.
The main object of this thesis was to study any local Enteromorpha population which appeared to have a dimorphic diplohaplontic life history. The writer, found evidence of such a life history in an Enteromorpha population in the Motunau River, North Canterbury. This thesis details a series of observations and experiments with the object of confirming this observation.
During preliminary experimental work, however, several additional problems emerged. These required investigation before the original objective could become meaningful. One of those problems was the classification of the populations studied.
Early attempts to classify the Motunau River population proved difficult. The characters usually considered to be of greatest taxonomic importance were found to vary considerably within the population. As a result a dichotomous key would not place a plant unambiguously into a single species. It was felt that a greater knowledge of the variation in the diagnostic characters was necessary before any species could be accurately identified.
In order to elucidate the systematic position as well as the life history of the Motunau Enteromorpha population it was necessary to establish cultures. Fertile plants had to be collected and zooid release effected in the laboratory. Extreme difficulty was experienced in both these respects. It was difficult to find any fertile plants and even more so to effect zooid release. Emphasis was therefore placed upon periodicity observations and the conditions influencing zooid release in the laboratory and natural environment.
Once the desired cultures were established, the extreme variability of orthodox taxonomic criteria led to the search for others, and the possibility of using embryology as a taxonomic criterion was investigated. Here additional problems emerged. Plants of the same age were observed to have widely different embryo form. This situation was found in a number of populations.
The objectives of this thesis therefore became to study (1) the natural variation of selected taxonomic characters, (2) zooid release in the natural environment and in the laboratory, (3) the variation in embryology of several populations, and (4) to determine the type of life history possessed by an Enteromorpha population growing in the
Motunau River, North Canterbury
Integrated approach to malaria prevention at household level in rural communities in Wakiso district, Uganda: impact evaluation of a pilot project
Background: The integrated approach to malaria prevention, which advocates for the use of several malaria prevention methods at households, is being explored to complement other existing strategies. We implemented a pilot project that promoted the integrated approach to malaria prevention in two rural communities in Wakiso district, Uganda.
Objectives: This paper presents the impact evaluation findings of the project carried out 2 years after implementation with a focus on changes in knowledge and practices on malaria prevention.
Methods: The project evaluation was cross-sectional in design and employed both quantitative and qualitative data collection methods. The quantitative survey was conducted among 540 households (household heads being participants) while the qualitative component involved 4 focus group discussions among community health workers (CHWs). Chi-square test was used to compare quantitative results from the evaluation with those of the baseline while thematic analysis was employed for qualitative data.
Results: There was a statistically significant positive change in malaria prevention practices in the evaluation compared with the baseline regarding indoor residual spraying (χ2 = 7.9, p = 0.019), mosquito screening of windows and ventilators (χ2 = 62.3, p = 0.001), and closing windows of houses before 6:00 pm (χ2 = 60.2, p < 0.001). The CHWs trained during the project were found to be highly knowledgeable on the various malaria prevention methods in the integrated approach, and continued to promote their use in the community.
Conclusion: Findings of the impact evaluation give promise that utilisation of integrated malaria prevention can be enhanced if use of multiple methods is promoted in communities
Ancient mitochondrial genomes unveil the origins and evolutionary history of New Zealand's enigmatic takahē and moho.
Many avian species endemic to Aotearoa New Zealand were driven to extinction or reduced to relict populations following successive waves of human arrival, due to hunting, habitat destruction and the introduction of mammalian predators. Among the affected species were the large flightless South Island takahē (Porphyrio hochstetteri) and the moho (North Island takahē; P. mantelli), with the latter rendered extinct and the former reduced to a single relictual population. Little is known about the evolutionary history of these species prior to their decline and/or extinction. Here we sequenced mitochondrial genomes from takahē and moho subfossils (12 takahē and 4 moho) and retrieved comparable sequence data from takahē museum skins (n = 5) and contemporary individuals (n = 17) to examine the phylogeny and recent evolutionary history of these species. Our analyses suggest that prehistoric takahē populations lacked deep phylogeographic structure, in contrast to moho, which exhibited significant spatial genetic structure, albeit based on limited sample sizes (n = 4). Temporal genetic comparisons show that takahē have lost much of their mitochondrial genetic diversity, likely due to a sudden demographic decline soon after human arrival (~750 years ago). Time-calibrated phylogenetic analyses strongly support a sister species relationship between takahē and moho, suggesting these flightless taxa diverged around 1.5 million years ago, following a single colonisation of New Zealand by a flighted Porphyrio ancestor approximately 4 million years ago. This study highlights the utility of palaeogenetic approaches for informing the conservation and systematic understanding of endangered species whose ranges have been severely restricted by anthropogenic impacts
High-Resolution Coproecology: Using Coprolites to Reconstruct the Habits and Habitats of New Zealand’s Extinct Upland Moa (Megalapteryx didinus)
Knowledge about the diet and ecology of extinct herbivores has important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes. The flightless ratite moa (Aves: Dinornithiformes) were New Zealand’s largest herbivores prior to their extinction soon after initial human settlement. Here we contribute to the knowledge of moa diet and ecology by reporting the results of a multidisciplinary study of 35 coprolites from a subalpine cave (Euphrates Cave) on the South Island of New Zealand. Ancient DNA analysis and radiocarbon dating revealed the coprolites were deposited by the extinct upland moa (Megalapteryx didinus), and span from at least 6,368±31 until 694±30 14C years BP; the approximate time of their extinction. Using pollen, plant macrofossil, and ancient DNA analyses, we identified at least 67 plant taxa from the coprolites, including the first evidence that moa fed on the nectar-rich flowers of New Zealand flax (Phormium) and tree fuchsia (Fuchsia excorticata). The plant assemblage from the coprolites reflects a highly-generalist feeding ecology for upland moa, including browsing and grazing across the full range of locally available habitats (spanning southern beech (Nothofagus) forest to tussock (Chionochloa) grassland). Intact seeds in the coprolites indicate that upland moa may have been important dispersal agents for several plant taxa. Plant taxa with putative anti-browse adaptations were also identified in the coprolites. Clusters of coprolites (based on pollen assemblages, moa haplotypes, and radiocarbon dates), probably reflect specimens deposited at the same time by individual birds, and reveal the necessity of suitably large sample sizes in coprolite studies to overcome potential biases in diet interpretation
History Repeats: Large Scale Synchronous Biological Turnover in Avifauna From the Plio-Pleistocene and Late Holocene of New Zealand
New Zealand's unique biodiversity is the product of at least 55 million years of geographic isolation, supplemented by persistent transoceanic migration. Palaeontological and genetic evidence suggest most New Zealand avifauna has colonized from Australia. We synthesize evolutionary genetic studies to show a previously unrecognized clustering of divergence times in Australian and New Zealand bird species pairs, across the avian phylogeny at the beginning of the Pleistocene, around 2.5 million years ago. The timing coincides with major climatic and vegetation changes with the initiation of the Plio-Pleistocene glacial cycles. Recent anthropogenic impacts and environmental modifications are replicating in some important ways Pleistocene glacial landscapes, resulting in a new wave of avian “native invaders” into New Zealand
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