New Perspectives on Mathematics Pedagogy

“New Perspectives on Mathematics Pedagogy” represents a serious attempt to understand pedagogy within mathematics classrooms. To that end, this symposium will address the key questions and issues surrounding mathematics pedagogy presently confronting vast numbers of researchers, as well as educators, and policy makers. Organised around presentations, responses, discussion and debate, the symposium is intended not only to enhance understanding but also to stimulate fresh thinking and initiate ongoing critical dialogue about the practice of mathematics pedagogy within teaching and learning settings

Compliance with children's television food advertising regulations in Australia

Extent: 6p.Background: The objective of this study was to assess the effectiveness of the Australian co-regulatory system in limiting children’s exposure to unhealthy television food advertising by measuring compliance with mandatory and voluntary regulations. An audit was conducted on food and beverage television advertisements broadcast in five major Australian cities during children’s programming time from 1st September 2010 to 31st October 2010. The data were assessed against mandatory and voluntary advertising regulations, the information contained in an industry report of breaches, and the Australian Guide to Healthy Eating. Results: During the two months of data collection there were a total of 951 breaches of the combined regulations. This included 619 breaches of the mandatory regulations (CTS) and 332 breaches of the voluntary regulations (RCMI and QSRI). Almost 83% of all food and beverages advertised during children’s programming times were for foods classified as ‘Extras’ in the Australian Guide to Healthy Eating. There were also breaches in relation to the amount of advertising repetition and the use of promotional appeals such as premium offers, competitions, and endorsements by popular children’s characters. The self-regulatory systems were found to have flaws in their reporting and there were errors in the Australian Food and Grocery Council’s compliance report. Conclusions: This audit suggests that current advertising regulations are inadequate. Regulations need to be closely monitored and more tightly enforced to protect children from advertisements for unhealthy foods.Michele Roberts, Simone Pettigrew, Kathy Chapman, Caroline Miller and Pascale Queste

"Nested" cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions

<p>Abstract</p> <p>Background</p> <p>Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt <it>Pyura stolonifera</it>, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit.</p> <p>Results</p> <p>Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within <it>Pyura stolonifera </it>in the different coastal communities they dominate.</p> <p>Conclusions</p> <p>This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the source region of a putative invader. "Nested" cryptic diversity, and the difficulties in correctly identifying invasive species that arise from it, represent a major challenge for managing biodiversity.</p

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements