Tephrochronology of marine sediments around the Island of Montserrat, Lesser Antilles volcanic arc

The recent history of the Soufrière Hills Volcano, Montserrat, Lesser Antilles volcanic arc, is reconstructed using data obtained from recently drilled submarine cores.Tephra layers in these cores preserve a record of the volcanic history of Montserrat back to ~250 ka on the basis of micropaleontology and stable isotope stratigraphy. Stratigraphic relationships identified in the cores collected in 2002 and 2005 document the fate of both pyroclastic flows entering the ocean to the east of Montserrat and carbonate-rich turbidites sourced from the carbonate platformssurrounding the islands of the Lesser Antilles. Using oxygen isotope stratigraphy, micropalaeontological analysis and Carbon-14 dating, it can be shown that three significant volcanic events, including the on-going eruption, have occurred over the last 12 ka. Preceding this was a time of volcanic quiescence, with three carbonate-rich turbidite events being documented in many of the cores. Our data suggest that these events occurred during Marine Isotope Stage 2, following the Last Glacial Maximum (LGM) and onset of post-glacial sea level rise.

Understanding the mechanism behind invasion of African lovegrass

African lovegrass (Eragrostis curvula) is a C4 perennial grass, native to southern Africa, that was accidentally introduced into Australia in the late 1900s as a contaminant of pasture seed. Its utility for pasture improvement and soil conservation was explored because of its recognised ability to grow in areas of low rainfall and on nutrient-poor sandy loams. Several different agronomic types have now been intentionally introduced across Australia. African lovegrass is now found in all Australian states and territories. It is a declared weed in 33 council areas of New South Wales, a declared pest plant in the ACT and Tasmania and a Regionally Prohibited Weed in 5 out of 11 regions in Victoria. Victoria has also placed it in the very serious threat category (Carr et al. 1992). In Queensland, it has yet to be declared except under local law in the Eidsvold shire (Leigh and Walton, in press).

Unravelling the mechanisms behind the invasion of an introduced and now undesirable grass species

The introduction of Eragrostis curvula (African Lovegrass, herafter Lovegrass) for pasture improvement across Australia has not been successful. Instead Lovegrass, a C4 perennial grass originating from Southern African, has proven unpalatable to stock and to have low nutritional value if stocks do eat it. It has spread prolifically along roadsides, stream banks, conservation areas and pastures. Because control efforts have not been effective, our aim was to determine the putative mechanisms responsible for the dominance of Lovegrass, specifically disturbance (selective grazing) and competition.

Malay Kingship in Kedah : Religion, Trade, and Society

The book probes and examines traditional sources of royal power and control, as well as indigenous socio-political systems in the Malay world. It is focused on the north-western Malaysian Sultanate of Kedah which is acknowledged as the oldest unbroken independent kingship line in the ‘Malay and Islamic world’ with 1,000 years of history. Little scholarly attention has been paid to its pre-modern history, society, religion, system of government and unique geographic situation, potentially controlling both land and sea lines of communication into the remainder of Southeast Asia. It will thus provide the first comprehensive treatment in English, or other languages, on Kedah’s pre-modern and nineteenth century historiography and can provide a foundation for comparative studies of the various Malay states which is presently lacking. The proposed book also sheds much needed light on a range of important topics in Malay history including: Kedah and the northern Melaka Straits history, colonial expansion and rivalry, Southeast Asian history and politics, interregional migration and the influence of the sea peoples or orang laut, traditional Malay socio-political and economic life, Islamic influences and the course of Thai-Malay relations. The book attempts to offer a new understanding, not only of Kedah, but of the political and cultural development of the entire Malay world and of its relationships with the broader forces in both its continental and maritime settings. It argues that Kedah does not seem to follow, and in fact, often seems to contradict what has been commonly been accepted as the “typical model” of the traditional Malay state. Thus it concludes that the ruling dynasty has historically exploited a wide range of unique environmental conditions, local traditions, global spiritual trends and economic forces to preserve and strengthen its political position. The scope and theme of book The Kedah Sultanate is the oldest unbroken independent kingship lines in the “Malay world” with 1,000 years of history, and arguably one of the oldest in the Islamic world. In this study I examine key geopolitical and spiritual attributes of Malay kingship that have traditionally cemented the ruler, the peoples, and the environment. Brief description of the primary audience for the book: There is little written in English or Malay on Kedah’s pre twentieth century history. The available sources only look at certain aspects of Kedah’s history, are outdated or are confined to a specific period often outside the scope of the book. It is therefore anticipated that the readership and market for the book includes: • Scholars of Southeast Asian history, Islam, kingship, trade. • Academics & Historians (including: Asian, Thai history, Islamic, Maritime, Persian, South Asian, Southeast Asian and Colonial) • Libraries • Students, particularly those in Malaysia (especially the states of Kedah, Perlis and Penang), Thailand and Singapore. • Universities • Scholars and students in Political Science & International Relations

4000 years of phenotypic change in an island bird: heterogeneity of selection over three microevolutionary timescales.

Pronounced phenotypic shifts in island populations are typically attributed to natural selection, but reconstructing heterogeneity in long-term selective regimes remains a challenge. We examined a scenario of divergence proposed for species colonizing a new environment, involving directional selection with a rapid shift to a new optimum and subsequent stabilization. We provide some of the first empirical evidence for this model of evolution using morphological data from three timescales in an island bird, Zosterops lateralis chlorocephalus. In less than four millennia since separation from its mainland counterpart, a substantial increase in body size has occurred and was probably achieved in fewer than 500 generations after colonization. Over four recent decades, morphological traits have fluctuated in size but showed no significant directional trends, suggesting maintenance of a relatively stable phenotype. Finally, estimates of contemporary selection gradients indicated generally weak directional selection. These results provide a rare description of heterogeneity in long-term natural regimes, and caution that observations of current selection may be of limited value in inferring mechanisms of past adaptation due to a lack of constancy even over short time-frames.

Large body size in an island-dwelling bird : a microevolutionary analysis

Island races of passerine birds display repeated evolution towards larger body size compared with their continental ancestors. The Capricorn silvereye (Zosterops lateralis chlorocephalus) has become up to six phenotypic standard deviations bigger in several morphological measures since colonization of an island approximately 4000 years ago. We estimated the genetic variance-covariance (G) matrix using full-sib and 'animal model' analyses, and selection gradients, for six morphological traits under field conditions in three consecutive cohorts of nestlings. Significant levels of genetic variance were found for all traits. Significant directional selection was detected for wing and tail lengths in one year and quadratic selection on culmen depth in another year. Although selection gradients on many traits were negative, the predicted evolutionary response to selection of these traits for all cohorts was uniformly positive. These results indicate that the G matrix and predicted evolutionary responses are consistent with those of a population evolving in the manner observed in the island passerine trend, that is, towards larger body size.

Funds of knowledge of sorting and patterning : networks of exchange in a Torres Strait Island community

The purpose of this article is to describe a project with one Torres Strait Islander Community. It provides some insights into parents’ funds of knowledge that are mathematical in nature, such as sorting shells and giving fish. The idea of funds of knowledge is based the premise that people are competent and have knowledge that has been historically and culturally accumulated into a body of knowledge and skills essential for their functioning and well-being. This knowledge is then practised throughout their lives and passed onto the next generation of children. Through using a community research approach, funds of knowledge that can be used to validate the community’s identities as knowledgeable people, can be used as foundations for future learnings for teachers, parents and children in the early years of school. They can be the bridge that joins a community’s funds of knowledge with schools validating that knowledge.

Lattice-free models of cell invasion : discrete simulations and travelling waves

Invasion waves of cells play an important role in development, disease and repair. Standard discrete models of such processes typically involve simulating cell motility, cell proliferation and cell-to-cell crowding effects in a lattice-based framework. The continuum-limit description is often given by a reaction–diffusion equation that is related to the Fisher–Kolmogorov equation. One of the limitations of a standard lattice-based approach is that real cells move and proliferate in continuous space and are not restricted to a predefined lattice structure. We present a lattice-free model of cell motility and proliferation, with cell-to-cell crowding effects, and we use the model to replicate invasion wave-type behaviour. The continuum-limit description of the discrete model is a reaction–diffusion equation with a proliferation term that is different from lattice-based models. Comparing lattice based and lattice-free simulations indicates that both models lead to invasion fronts that are similar at the leading edge, where the cell density is low. Conversely, the two models make different predictions in the high density region of the domain, well behind the leading edge. We analyse the continuum-limit description of the lattice based and lattice-free models to show that both give rise to invasion wave type solutions that move with the same speed but have very different shapes. We explore the significance of these differences by calibrating the parameters in the standard Fisher–Kolmogorov equation using data from the lattice-free model. We conclude that estimating parameters using this kind of standard procedure can produce misleading results.

Yersinia high pathogenicity island genes modify the Escherichia coli primary metabolome independently of siderophore production

Bacterial siderophores may enhance pathogenicity by scavenging iron, but their expression has been proposed to exert a substantial metabolic cost. Here we describe a combined metabolomic-genetic approach to determine how mutations affecting the virulence-associated siderophore yersiniabactin affect the Escherichia coli primary metabolome. Contrary to expectations, we did not find yersiniabactin biosynthesis to correspond to consistent metabolomic shifts. Instead, we found that targeted deletion of ybtU or ybtA, dissimilar genes with similar roles in regulating yersiniabactin expression, were associated with a specific shift in arginine pathway metabolites during growth in minimal media. This interaction was associated with high arginine levels in the model uropathogen Escherichia coli UTI89 compared to its ybtU and ybtA mutants and the K12 strain MG1655, which lacks yersiniabactin-associated genes. Because arginine is not a direct yersiniabactin biosynthetic substrate, these findings show that virulence-associated secondary metabolite systems may shape bacterial primary metabolism independently of substrate consumption

Late Quaternary vegetation history of North Stradbroke Island, Queensland, eastern Australia

Currently there is a paucity of records of late Quaternary palaeoenvironmental variability available from the subtropics of Australia. The three continuous palaeoecological records presented here, from North Stradbroke Island, subtropical Queensland, assist in bridging this large spatial gap in the current state of knowledge. The dominance of arboreal taxa in the pollen records throughout the past >40,000 years is in contrast with the majority of records from temperate Australia, and indicates a positive moisture balance for North Stradbroke Island. The charcoal records show considerable inter-site variability indicating the importance of local-scale events on individual records, and highlighting the caution that needs to be applied when interpreting a single site as a regional record. The variability in the burning regimes is interpreted as being influenced by both climatic and human factors. Despite this inter-site variability, broad environmental trends are identifiable, with changes in the three records comparable with the OZ-INTIMATE climate synthesis for the last 35,000 years.

The association between pterygium and conjunctival ultraviolet autofluorescence : The Norfolk Island Eye Study

Purpose: To investigate the association between conjunctival ultraviolet autofluorescence (UVAF), a biomarker of ocular ultraviolet radiation (UVR) exposure, and prevalent pterygium. Methods: We conducted a cross-sectional study on Norfolk Island, South Pacific. All permanent residents aged ‡15 were invited to participate. Participants completed a sun exposure questionnaire and underwent autorefraction and slit lamp biomicroscope examination. Area of conjunctival UVAF (sum of temporal ⁄ nasal area in right and left eyes) was determined using computerized methods. Multivariate logistic and linear regression models were used to estimate the associations with pterygia and UVAF, respectively. Results: Of 641 participants, 70 people (10.9%) had pterygium in one or both eyes, and prevalence was higher in males (15.0% versus 7.7%, p = 0.003). Significant independent associations with pterygium in any eye were UVAF (per 10 mm2) [odds ratio (OR) 1.16, 95% confidence interval (CI) 1.16–1.28, p = 0.002], tanning skin phenotype (OR 2.17,1.20–3.92, p = 0.010) and spending more than three-quarters of the day outside (OR 2.22, 1.20–4.09, p = 0.011). Increasing quartile of UVAF was associated with increased risk of pterygium following adjustment of age, sex and time outdoors (pTrend = 0.002). Independent associations with increasing UVAF (per 10 mm2) were decreasing age, time outdoors, skin type and male gender (all p < 0.001). UVAF area correlated well with the duration of outdoor activity (pTrend < 0.001). Conclusion: Pterygium occurs in approximately one-tenth of Norfolk Islanders. Increasing conjunctival UVAF is associated with prevalent pterygia, confirming earlier epidemiological, laboratory and ray-tracing studies that pterygia are associated with UVR. Protection from the sun should be encouraged to reduce the prevalence of pterygium in the community.

An X chromosome association scan of the Norfolk Island genetic isolate provides evidence for a novel migraine susceptibility locus at Xq12

Migraine is a common and debilitating neurovascular disorder with a complex envirogenomic aetiology. Numerous studies have demonstrated a preponderance of women affected with migraine and previous pedigree linkage studies in our laboratory have identified susceptibility loci on chromosome Xq24-Xq28. In this study we have used the genetic isolate of Norfolk Island to further analyse the X chromosome for migraine susceptibility loci. An association approach was employed to analyse 14,124 SNPs spanning the entire X chromosome. Genotype data from 288 individuals comprising a large core-pedigree, of which 76 were affected with migraine, were analysed. Although no SNP reached chromosome-wide significance (empirical α = 1×10−5) ranking by P-value revealed two primary clusters of SNPs in the top 25. A 10 SNP cluster represents a novel migraine susceptibility locus at Xq12 whilst a 11 SNP cluster represents a previously identified migraine susceptibility locus at Xq27. The strongest association at Xq12 was seen for rs599958 (OR = 1.75, P = 8.92×10−4), whilst at Xq27 the strongest association was for rs6525667 (OR = 1.53, P = 1.65×10−4). Further analysis of SNPs at these loci was performed in 5,122 migraineurs from the Women’s Genome Health Study and provided additional evidence for association at the novel Xq12 locus (P<0.05). Overall, this study provides evidence for a novel migraine susceptibility locus on Xq12. The strongest effect SNP (rs102834, joint P = 1.63×10−5) is located within the 5′UTR of the HEPH gene, which is involved in iron homeostasis in the brain and may represent a novel pathway for involvement in migraine pathogenesis.