Igneous Rock Associations 20. Pearce Element Ratio Diagrams: Linking Geochemical Data to Magmatic Processes

It has been nearly fifty years since Tom Pearce devised a type of element ratio diagram that isolates the effects of crystal fractionation and accumulation (sorting) hidden in the chemistry of a suite of igneous rocks. Here, we review the guiding principles and methods supporting the Pearce element ratio paradigm and provide worked examples with data from the Mauna Ulu lava flows (erupted 1970–1971, Kilauea Volcano, Hawaii). Construction of Pearce element ratio diagrams requires minimum data; a single rock analysis can suffice. The remaining data test the model. If the data fit the model, then the model is accepted as a plausible or likely explanation for the observed chemical variations. If the data do not fit, the model is rejected. Successful applications of Pearce element ratios require the presence and identification of conserved elements; elements that remain in the melt during the processes causing the chemical diversity. Conserved elements are identified through a priori knowledge of the physical-chemical behaviour of the elements in rock-forming processes, plots of weight percentages of pairs of oxides against each other, or by constant ratios of two elements. Three kinds of Pearce element ratio diagrams comprise a model: conserved element, assemblage test, and phase discrimination diagrams. The axial ratios for Pearce ratio diagrams are combinations of elements chosen on the basis of the chemical stoichiometry embedded in the model. Matrix algebra, operating on mineral formulae and analyses, is used to calculate the axis ratios. Models are verified by substituting element numbers from mineral formulae into the ratios. Different intercepts of trends on Pearce element ratio diagrams distinguish different magma batches and, by inference, different melting events. We show that the Mauna Ulu magmas derive from two distinct batches, modified by sorting of olivine, clinopyroxene, plagioclase and, possibly, orthopyroxene (unobserved).RÉSUMÉIl y a près de cinquante ans Tom Pearce a conçu un genre de diagramme de ratio d’éléments qui permet d’isoler les effets de la cristallisation fractionnée et de l'accumulation cristalline (tri) au sein de la chimie d'une suite de roches ignées. Dans le présent article, nous passons en revue les principes et les méthodes étayant le paradigme de ratio d’éléments de Pearce, et présentons des exemples pratiques à partir de données provenant de coulées de lave du Mauna Ulu (éruption 1970–1971 du volcan Kilauea, Hawaii). La confection des diagrammes de ratio d’éléments de Pearce requière un minimum de données; une seule analyse de roche peut suffire. Les données restantes servent à tester le modèle. Si les données sont conformes au modèle, alors le modèle est accepté comme explication plausible ou probable des variations chimiques observées. Si les données ne correspondent pas, le modèle est rejeté. Les applications réussies des ratios d’éléments de Pearce requièrent la présence et l'identification d’éléments conservés; éléments qui demeurent dans la masse fondue au cours des processus causant la diversité chimique. Les éléments conservés sont identifiés par la connaissance a priori du comportement physico-chimique des éléments dans les processus de formation des roches, le positionnement sur la courbe des pourcentages pondérés de pairs d'oxydes les uns contre les autres, ou par des ratios constants de deux éléments. Trois types de diagrammes de Pearce de ratio d’éléments constituent un modèle: élément conservé, test d'assemblage, et diagrammes de phase discriminant. Les ratios axiaux pour les diagrammes de ratio d’éléments de Pearce sont des combinaisons d'éléments choisis sur la base de la stœchiométrie inhérente au modèle. L’algèbre matricielle, appliquée à des formules minérales et à des analyses, est utilisée pour calculer les ratios axiaux. Les modèles sont vérifiés en utilisant les nombres d’élément des formules minérales dans les ratios. Différentes intersections dans les diagrammes de ratios d’éléments de Pearce distinguent différents lots de magma et, par inférence, différentes coulées. Nous montrons que les magmas de Mauna Ulu proviennent de deux lots distincts, modifiés par l’extraction de l'olivine, de clinopyroxène, de plagioclase et, éventuellement, orthopyroxène (non observé)

Plausible responses to the threat of rapid sea-level rise for the Thames Estuary

This paper considers the perceptions and responses of selected stakeholders to a scenarion of rapid rise in sea-level due to the collapse of the West Antarctic ice sheet, which could produce a global rise in sea-level of 5 to 6 metres. Through a process of dialogue involving one-to one interviews and a one-day policy exercise, we addressed influences on decision-making when information is uncertain and our ability to plan, prepare for and implement effective ways of coping with this extreme scenario. Through these interactions we hoped to uncover plausible responses to the scenario and identify potential weaknesses in our current flood management approaches to dealing with such an occurrence. By undertaking this exploratory exercise we hoped to find out whether this was a feasible way to deal with such a low probability but high consequence scenario. It was the process of finding a solution that interested us rather than the technical merits of one solution over another. We were not intending to produce definitive set of recommendations on how to respond but to gain insights into the process of making a decision, specifically what influences it and what assumptions are made.Sea level rise, London

Extensive alternative splicing within the amino-propeptide coding domain of α2(XI) procollagen mRNAs: Expression of transcripts encoding truncated pro-α chains

Heterogeneity in type XI procollagen structure is extensive because all three α(XI) collagen genes undergo complex alternative splicing within the amino-propeptide coding domain. Exon 7 of the human and exons 6-8 of the mouse α2(XI) collagen genes, encoding part of the amino-propeptide variable region, have recently been shown to be alternatively spliced. We show that exon 6-containing mRNAs for human α2(XI) procollagen are expressed at 28 weeks in fetal tendon and cartilage but not at 38-44 days or 11 weeks. In the mouse, exon 6 is expressed in chondrocytes from 13.5 days onward. We recently identified conserved sequences within intron 6 of the human and mouse α2(XI) collagen genes, containing additional consensus splice acceptor and donor sites that potentially increase the size of exon 7, dividing it into three parts, designated 7A, 7B, and 7C. We show by reverse transcription polymerase chain reaction and in situ hybridization that these potential splice sites are used to yield additional α2(XI) procollagen mRNA splice variants that are expressed in fetal tissues. In human, expression of exon 7B-containing transcripts may be developmental stage-specific. Interestingly, inclusion of exon 7A or exon 7B in human and mouse α2(XI) procollagen mRNAs, respectively, would result in the insertion of an in-frame termination codon, suggesting that some of the additional splice variants encode a truncated pro-α2(XI) chain

Just for Me Engagement

BACKGROUND The Mathematics Education Support Hub (MESH) at UWS is a unit within the learning and teaching portfolio with a remit to provide mathematical and statistical help to all students within the university. One method of enabling this support has been a mathematics library roving program, introduced in 2013 to complement literacy support which was already operating in the library. AIMS The program aims to provide “just in time” support for students experiencing difficulty with the mathematical and statistical components of their subjects in a non-confrontational environment. A secondary aim is to increase student confidence in their own mathematical abilities. DESCRIPTION OF INTERVENTION The MESH library roving program began in the Autumn session 2013 and has continued during Spring 2013 and Autumn 2014. Support is provided by MESH staff who ‘rove’ the various campus libraries for two hour sessions at well-advertised times throughout the teaching and study vacation periods of the semester. These library rovers assist individual students and groups by encouraging students to engage with the mathematical and statistical content of their subject through a process of guided discovery of the material as well as direct responses to enquiries. The time taken for such interventions range from a few minutes to approximately half an hour, with students with problems requiring longer discussion usually referred back to subject teaching teams for further clarification. Students availing themselves of the service range from first year to post graduate with problems coming from subjects as diverse as business, finance, biomechanics, law and engineering as well as mathematics and statistics subjects. DESIGN AND METHODS Each library consultation is recorded on an electronic form and features of the consultation are noted. The data collected includes the campus, number of students in a group, student year of study, length of time spent with the group, unit or discipline area in which assistance is provided as well as if a group or student has been seen previously. At the end of 2013 a research project conducted in conjunction with the academic literacy library roving program collected survey responses from students, library staff and rovers. Analysis of this data along with surveys of students, library staff and rovers will show the patterns of use and responses of various stakeholders to the program. RESULTS The data collected for this project are still being processed and it is anticipated features of the analysis will be presented. It is envisaged that models of student behaviour gleaned from this analysis will form the basis of the results. The nature of requests from students and how these are dealt with by the rovers will also be presented. Responses from student, librarian and rover surveys will also provide an indication of student engagement with the service. CONCLUSIONS The intention of this project is to use the results to fine tune the impact and delivery of the library roving program

Tertiary students’ engagement in a mathematics support program

Background Mathematics is often perceived to be a difficult subject and students struggle with it. A combination of factors including a compromise with tertiary admission requirements, such as prerequisites, a link between Federal funding and student number at an institution, relaxed mathematics requirement to complete secondary education, ATAR based admission to programs, and, admission of mature age and international students with diverse backgrounds elevates the number of tertiary students struggling with mathematics. At UWS, to support these students with their mathematics, various services including lecturer consultation time, tutorials, pre- and within-semester workshops, library roving, online tutoring, peer-assisted student support and free internet sites are made available to them. This study deals with students’ engagement in pre-semester workshops. Aims The aim of this study was to evaluate (i) age and gender based influences on students’ engagement in the workshops, (ii) perceived reasons to participate in the workshops and (iii) post-workshops perceptions of their mathematical competency. Methodology The workshops were advertised on the UWS web and emails were sent to the prospective students to encourage them to register for these voluntary workshops. The workshops aimed to revise basics of algebra, trigonometry, calculus and statistics to prepare students for their first year mathematics units. The students attended 1 – 3 days workshops in these areas before starting degree programs at UWS. The students were asked to complete two surveys one each on their first- and last-day of the program, and, pre- and post-achievement tests. The first- and last-day survey targeted students’ reasons to participate in and satisfaction from attending the workshops respectively. Only 57.3% of those who completed first day survey (616) from 2011 to 2014 completed the last-day survey. The data were analysed to evaluate areas of interest specified under aims. Results The results of the study revealed that students’ intention to engage and actual engagement in the workshops were significantly different. The participation was significantly higher of male (62.1%) than female (37.9%) students and 33.5% of them were older than 20 years indicating a high percentage of matured age students. The major reason for participation in the workshops was their perceived weak or very weak background in these areas. The number of weak or very weak students in calculus and statistics was higher than algebra and trigonometry. Analysis of post-workshops survey revealed a significant improvement in their perceived knowledge of these mathematics areas. This claim was partly supported by significantly improved post-test scores in 2014. Gender, age and year to year based trends in these findings will also be discussed. Conclusions and Future Directions Students perceived their engagement in pre-semester workshops was helpful in improving their desired mathematics content knowledge. Further research to investigate students’ performance in their required mathematics subjects and programs is warranted

Targeting climate adaptation to safeguard and advance the Sustainable Development Goals

The international community has committed to achieve 169 Sustainable Development Goal (SDG) targets by 2030 and to enhance climate adaptation under the Paris Agreement. Despite the potential for synergies, aligning SDG and climate adaptation efforts is inhibited by an inadequate understanding of the complex relationship between SDG targets and adaptation to impacts of climate change. Here we propose a framework to conceptualise how ecosystems and socio-economic sectors mediate this relationship, which provides a more nuanced understanding of the impacts of climate change on all 169 SDG targets. Global application of the framework reveals that adaptation of wetlands, rivers, cropland, construction, water, electricity, and housing in the most vulnerable countries is required to safeguard achievement of 68% of SDG targets from near-term climate risk by 2030. We discuss how our framework can help align National Adaptation Plans with SDG targets, thus ensuring that adaptation advances, rather than detracts from, sustainable development

University of Michigan Library Informational Posters for CI Days 2013

The University of Michigan Library displayed a series of four posters to inform participants in the annual CyberInfrastructure (CI) Days about services, activities, and resources available to them to support their research needs. CI Days is coordinated and hosted by Advanced Research Computing at the University of Michigan, a part of the office of the Vice President for Research.Advanced Research Computing at the University of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/101738/1/CIDays13_ORCIDFinal.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101738/2/CIDays13_DataCite_Final.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101738/3/CIDays13_Poster_Sferdean_Li_York_Green.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/101738/4/CI Days info poster.pdf-

Faculty of Public Accounting. Volume 9 No. 12 June 1991

Nuestra Facultad de Contaduría ha cumplido recientemente 17 años de labores y nada mejor para celebrar este aniversario que la noticia sobre la aproba- ción dada por el ICFES al programa de Especialización en Hevisoría Fiscal y Auditoría Externa que esperamos iniciar en el mes de septiembre. Es el primer programa aprobado a una Universidad en el país para adelantar estudios de formación avanzada en estas disciplinas. En la ciudad hermana de Cúcuta se celebrará desde agosto 14 al 17 el X Congreso Colombiano de Contadores Públicos y el primer encuentro Colombo Venezolano de Profesionales de la Contaduría. La organización del evento espera contar con la asístencia de nutridas delegaciones de todas las ciudades del país con el loable propósito de buscar la unificación en una sola agremiación de todos los Contadores Públicos de Colombia.Presentación. - 2 Quinto encuentro colombiano de investigaciób de la Facuktad de Contaduría Pública UNAB. -3 Primer encuentro colombiano de investigación de la Ciencia Contable. 6 Inventario de investigación de la Facultad. - 9Our School of Accounting has recently completed 17 years of work and there is nothing better to celebrate this anniversary than the news about the approval given by ICFES to the Specialization Program in Fiscal Audit and External Audit that we hope to start in the month of September. It is the first program approved for a University in the country to carry out advanced training studies in these disciplines. In the sister city of Cúcuta, the X Colombian Congress of Public Accountants and the first Colombo-Venezuelan meeting of Accounting Professionals will be held from August 14 to 17. The organization of the event hopes to have the assistance of large delegations from all the cities of the country with the laudable purpose of seeking the unification in a single union of all Public Accountants of Colombia