An investigation of crustal contamination through petrology and geochemisty

The contamination of mantle-derived magmas by the continental crust is an important process during petrogenesis of volcanic rocks at active continental margins e.g. The Andes. Investigating the evolution of continental arc magmas is, however, hampered by our limited knowledge of, and poor constraints on, the nature of the underlying crustal basement and the mechanisms of crustal anatexis. This thesis reports results from: 1) a whole rock geochemical and in-situ geochronological investigation of a suite of crustal xenoliths from the Bolvian Altiplano, Central Andes; 2) a whole rock geochemical study of the xenoiths’ host lavas and; 3) detailed in-situ geochemical studies of crustal partial melts (quenched to glasses) trapped within their crustal progenitors from Bolivia, NE China and SE Spain. Sampled crustal xenoliths from the Bolivan Altiplano provide a rare insight into the nature of the Central Andean continental basement and reveal lithological and geochemical heterogeneity exists at depth with 87 Sr/86 Sr values extending to 0.7368 which is more radiogenic than any Srisotopic signature exhibited by the recent (< 60 Ma) volcanic record. In-situ U-Pb dating of zircon separates reveal predominant age peaks at 1.7-1.9 Ga, 1.0-1.2 Ga and 495-380 Ma which correspond to periods of supercontinent formation and break-up e.g. construction of Rodinia. Lavas erupted from monogenetic centres on the eastern Bolivian Altiplano show petrographic and geochemical evidence for crustal contamination. The geochemical heterogeneity exhibited by the lavas is, however, difficult to reconcile through simple two component crust-magma interaction models (bulk mixing, AFC and EC-AFC). Instead, contamination is inferred to have involved numerous crustal components. The geochemical signatures observed in lavas from monogenetic centres towards the active Andean arc (between ~18-21o S) are distinct (e.g. lower 87 Sr/86 Sr, higher Sr/Y, higher Ba/Nb at higher Zr/Nb) and may indicate a lower degree of crust-magma interaction, an increase in the contribution from slab-derived fluids and thinner crust arc-wards, the latter which has previously been inferred from geophysical studies. In-situ analysis of anatectic melts reveals that Sr-isotopic disequilibrium between a crustal melt and its source can exist on the sub-millimetre scale. This is understood to reflect the melting of aged minerals with different Rb/Sr (and therefore 87 Sr/86 Sr) more quickly than the isotopic composition can diffusively equilibrate between melt and minerals. Results suggest therefore that crustal anatexis can produce melts which are geochemically heterogeneous both spatially and temporally. This highlights the need for detailed microscopic investigations coupled with petrogenetic modelling in order to develop a more robust characterisation and well-constrained quantification of crustal contamination in open magmatic systems

The use of prereferral interventions: The student assistance.

The national special education mandate, the Education for All Handicapped Children Act, also known as Public Law 94-142, was enacted by Congress in 1975. Since that time many politicians, education agencies, and taxpayers, as well as some educators, have become alarmed at what has been perceived as the overexpansion of special education services and their skyrocketing costs. Fiscal problems in education account in part for the growing concerns about the expansion of special education. Limited state and federal resources are available for funding special education. Taxpayer revolts, particularly regarding local property taxes, limit the taxation levies available to finance education

Mabel L. Robinson Correspondence

Entries include brief biographical information, a typed biography, a typed letter on Bayberry Farm stationery from Robinson\u27s North Brooklin, Maine, summer home, typed and handwritten letters on personal stationery including a note that she had read a letter from the Maine State Library to her workshop at Columbia University, and a typed letter of correspondence from Bonino on Random House, Inc., stationery presenting books for the Maine Author Collection

Health outcomes of smoking during pregnancy and the postpartum period: an umbrella review

BACKGROUND: Smoking during pregnancy (SDP) and the postpartum period has serious health outcomes for the mother and infant. Although some systematic reviews have shown the impact of maternal SDP on particular conditions, a systematic review examining the overall health outcomes has not been published. Hence, this paper aimed to conduct an umbrella review on this issue. METHODS: A systematic review of systematic reviews (umbrella review) was conducted according to a protocol submitted to PROSPERO ( CRD42018086350 ). CINAHL, EMBASE, MEDLINE, PsycINFO, Web of Science, CRD Database and HMIC databases were searched to include all studies published in English by 31 December 2017, except those focusing exclusively on low-income countries. Two researchers conducted the study selection and quality assessment independently. RESULTS: The review included 64 studies analysing the relationship between maternal SDP and 46 health conditions. The highest increase in risks was found for sudden infant death syndrome, asthma, stillbirth, low birth weight and obesity amongst infants. The impact of SDP was associated with the number of cigarettes consumed. According to the causal link analysis, five mother-related and ten infant-related conditions had a causal link with SDP. In addition, some studies reported protective impacts of SDP on pre-eclampsia, hyperemesis gravidarum and skin defects on infants. The review identified important gaps in the literature regarding the dose-response association, exposure window, postnatal smoking. CONCLUSIONS: The review shows that maternal SDP is not only associated with short-term health conditions (e.g. preterm birth, oral clefts) but also some which can have life-long detrimental impacts (e.g. obesity, intellectual impairment). IMPLICATIONS: This umbrella review provides a comprehensive analysis of the overall health impacts of SDP. The study findings indicate that while estimating health and cost outcomes of SDP, long-term health impacts should be considered as well as short-term effects since studies not including the long-term outcomes would underestimate the magnitude of the issue. Also, interventions for pregnant women who smoke should consider the impact of reducing smoking due to health benefits on mothers and infants, and not solely cessation

Investigating methods of visualising translation in schizosaccharomyces pombe

Gene expression is compartmentalised in eukaryotes due to the nuclear envelope separating the nuclear processes of transcription and pre-mRNA processing from cytoplasmic translation. While ribosomes are synthesised in the nucleus, it is understood that a number of mechanisms keep them inactive until they reach the cytoplasm, where they mature to become translation-competent. However, this consensus view is being challenged by a growing body of evidence in support of nuclear translation. A newly developed technique, known as ribopuromycylation (RPM), had reported the presence of puromycin-bound nascent peptides on immobilised ribosomes in the nuclei of human cells. I investigated whether this method could be used, combined with chromatin immunoprecipitation, to determine whether nuclear ribosomes can cotranscriptionally translate nascent transcripts in Schizosaccharomyces pombe. Surprisingly, I discovered that, in contrast to that reported in the original study, immobilising ribosomes with translation elongation inhibitors does not lead to retention of puromycylated peptides on ribosomes in either S. pombe, Drosophila melanogaster or HeLa cells. However, I show here preliminary data which suggest that despite puromycylated peptides being released from the ribosome, puromycin immunostaining might still be used to visualise the sub­ cellular localisation of ribosomes inS. pombe, along with other approaches which I also describe

Potential for health economics to influence policies on tobacco use during pregnancy in low-income and middle-income countries:a qualitative case study

INTRODUCTION: Tobacco control during pregnancy is a policy priority in high-income countries (HICs) because of the significant health and inequality consequences. However, little evidence exists on interventions to reduce tobacco use in low-income and middle-income countries (LMICs), especially for pregnant women. This study aimed to assess how health economics evidence, which is mainly produced in HICs, could be adopted for tobacco cessation policies for pregnant women in LMICs. METHODS: A qualitative case study was conducted in an international public health organisation. The organisation was chosen due to its capacity to influence health policies around the world. Tobacco control experts working in the organisation were identified through purposeful sampling and snowballing. Semistructured interviews were conducted with 18 informants with relevant experience of countries from all of the regions covered by the organisation. Data were analysed using the framework method. RESULTS: In practice, tobacco cessation during pregnancy was not viewed as a priority in LMICs despite international recognition of the issue. In LMICs, factors including the recorded country-specific prevalence of tobacco use during pregnancy, availability of healthcare resources and the characteristics of potential interventions all affected the use of health economics evidence for policy making. CONCLUSION: The scale of tobacco use among pregnant women might be greater than reported in LMICs. Health economics evidence produced in HICs has the potential to inform health policies in LMICs around tobacco cessation interventions if the country-specific circumstances are addressed. Economic evaluations of cessation interventions integrated into antenatal care with a household perspective would be especially relevant in LMICs

Using online chat to enhance peer learning while on fieldwork placements

Students in applied science disciplines in the School of Community Health at Charles Sturt University undertake fieldwork in urban, rural and remote areas throughout Australia and overseas (e.g. Vietnam) in each of the four years of their course. As students are situated in a diversity of locations, the ability to offer academic support is greatly reduced, whilst the opportunity for peer support is non-existent. Online chat facilities are introduced to the students in first year and are available each time students are on fieldwork placements. During a specified time each week, students and their lecturer logon to discuss issues of importance to students. Peer learning and collegial support are significant outcomes of these sessions. Since its inception in 1999, the use of online chat for fieldwork support has been adopted by other programs such as occupational therapy, physiotherapy and social work in Australia and overseas

Towards optimum smoking cessation interventions during pregnancy: a household model to explore cost‐effectiveness

BACKGROUND AND AIMS: Previous economic evaluations of smoking cessation interventions for pregnant women are limited to single components, which do not in isolation offer sufficient potential impact to address smoking cessation targets. To inform the development of more appropriate complex interventions, we (1) describe the development of the Economics of Smoking in Pregnancy: Household (ESIP.H) model for estimating the life‐time cost‐effectiveness of smoking cessation interventions aimed at pregnant women and (2) use a hypothetical case study to demonstrate how ESIP.H can be used to identify the characteristics of optimum smoking cessation interventions. METHODS: The hypothetical intervention was based on current evidence relating to component elements, including financial incentives, partner smoking, intensive behaviour change support, cigarettes consumption and duration of support to 12 months post‐partum. ESIP.H was developed to assess the life‐time health and cost impacts of multi‐component interventions compared with standard National Health Service (NHS) care in England. ESIP.H considers cigarette consumption, partner smoking and some health conditions (e.g. obesity) that were not included in previous models. The Markov model's parameters were estimated based on published literature, expert judgement and evidence‐based assumptions. The hypothetical intervention was evaluated from an NHS perspective. RESULTS: The hypothetical intervention was associated with an incremental gain in quitters (mother and partner) at 12 months postpartum of 249 [95% confidence interval (CI) = 195–304] per 1000 pregnant smokers. Over the long‐term, it had an incremental negative cost of £193 (CI = –£779 to 344) and it improved health, with a 0.50 (CI = 0.36–0.69) increase in quality‐adjusted life years (QALYs) for mothers, partners and offspring, with a 100% probability of being cost‐effective. CONCLUSIONS: The Economics of Smoking in Pregnancy: Household model for estimating cost‐effectiveness of smoking cessation interventions aimed at pregnant women found that a hypothetical smoking cessation intervention would greatly extend reach, reduce smoking and be cost‐effective