The density of primes in orbits of z^d + c

Given a polynomial f(z) = z^d + c over a global field K and a_0 in K, we study the density of prime ideals of K dividing at least one element of the orbit of a_0 under f. The density of such sets for linear polynomials has attracted much study, and the second author has examined several families of quadratic polynomials, but little is known in the higher-degree case. We show that for many choices of d and c this density is zero for all a_0, assuming K contains a primitive dth root of unity. The proof relies on several new results, including some ensuring the number of irreducible factors of the nth iterate of f remains bounded as n grows, and others on the ramification above certain primes in iterated extensions. Together these allow for nearly complete information when K is a global function field or when K=Q(zeta_d).Comment: 27 page

Physical activity, weight status and diet in adolescents: are children meeting the guidelines?

Childhood obesity is on the increase and maintaining regular physical activity and consuming a healthy diet have become essential tools to combat the condition. The United Kingdom government has recommended guidelines for optimal levels of diet and activity in children. The aim of this paper is to describe and compare self-reported physical activity levels, diet, and Body Mass Indices (BMI) amongst adolescent children, aged 11-15, in the South West (SW) and North West (NW) regions of England and to see if these children were meeting the current targets for optimal levels of: physical activity; fruit/vegetable consumption; fat consumption and BMI. We report the results of a cross-sectional survey of four secondary schools and 1,869 children using the self-reported Western Australian Child and Adolescent Physical Activity and Nutrition Survey (CAPANS) physical activity instrument and a food intake screener questionnaire, in summer and winter. We found that 25% (469/1869) 95% CI: 23% to 27%, of children engaged in 60 minutes of moderate to vigorous physical activity per day; 53% (995/1866) 95% CI: 51% to 56%, took 5 portions of fruit and vegetables per day; while 22% (407/1861) 95% CI: 20% to 24% consumed recommended amount of fats, and 23.7% (276/1164) 95% CI: 21% to 26%, of pupils were obese or overweight as classified by their BMI. Self reported physical activity in young people regardless of area is lower than previously reported and the lack of students engaging in 60 minutes moderate to vigorous activity could have serious public health consequences. If sustained, this could lead to more overweight adults, and more ill health

Physical activity among adolescents and barriers to delivering physical education in Cornwall and Lancashire, UK: a qualitative study of heads of PE and heads of schools. BMC Public Health Journal 2008 Aug 1;8:273.

BACKGROUND: Recent initiatives have been introduced by the UK government into secondary schools to increase pupils' access to physical activity (PA). Despite this, not enough is known about pupils' levels of physical activity or whether the delivery of these initiatives in schools facilitates or creates a barrier for pupils' PA. The aim of this study was to gain an understanding of adolescents PA levels from the perspective of those responsible for delivering physical education (PE) in schools; heads of PE (HOPE) and heads of school (HS). METHODS: Seventeen semi-structured qualitative interviews were carried out with a snowball sample of HOPE and HS in schools in the Northwest and Southwest of England. Thematic data analysis using NVIVO was used to identify emergent themes.RESULTS:17 core themes were generated, 12 of which confirmed the findings from similar research. However, five themes relating to 'ethos of performance/elitism', 'lower fitness leads to lower ability', 'undervaluing activities within PE dept' or school as a whole', 'role of the school' and 'PE department doing all it can' offer valuable new insight into the factors which may encourage or prevent PA inside or outside the curriculum. CONCLUSION: Despite many positive perceptions of the delivery of PE in schools, it is evident that barriers still exist within that delivery which discourages physical activity. More research is needed to particularly address the complex issues of elitism and the ethos of PA in schools

Inhaled corticosteroids versus long-acting beta -agonists for chronic obstructive pulmonary disease (Review).

Long-acting beta(2)-agonists and inhaled corticosteroids can be used as maintenance therapy by patients with moderate to severe chronic obstructive pulmonary disease. These interventions are often taken together in a combination inhaler. However, the relative added value of the two individual components is unclear

A study of the local pressure field in turbulent shear flow and its relation to aerodynamic noise generation Semiannual status report, 1 Aug. 1970 - 31 Jan. 1971

Relation of Eulerian and Lagrangian structure of pseudosound pressure and velocity fields in turbulent shear flow to aerodynamic noise generatio

Vertical Foreclosure and International Trade Policy

We examine conditions under which a low cost vertically integrated manufacturer has an incentive to export an intermediate product to its higher cost (vertically integrated) rival rather than to vertically foreclose, fully cutting off supplies. The nature of supply conditions in the importing country, the size of an import tariff on the final good and optimal policy by the exporting country are all shown to be important for this decision. The exporting country may gain by taxing exports of the final (Cournot) product even though, under Cournot competition, an export subsidy is optimal in the absence of a market for intermediates. In this case, optimal policy also requires an export tax on intermediates, but the higher tax on final goods serves to divert sales to the more profitable market for intermediates increasing the extent of vertical supply. It is optimal to tax the export of both goods or to subsidize the export of both goods. It is never optimal to tax one and subsidize the other.

The state, the universities and liberal legal education: students’ views from England, South Africa and Mauritius

English university departments are increasingly forging teaching links with overseas universities whether through franchise arrangements, by setting up overseas campuses linked to the home institution or by exchanging students. At Induction new students, both at home and overseas, are introduced into the academy in part by staff exploring what university education means and what are the mutual expectations of lecturers and students. In countries as diverse as China, India, Malaysia, Mauritius, Dubai, South Africa there are exchanges of students and, in some instances, close collaborative links with English universities. Little attention however has been given to investigating differing ideas on the part of students about the nature of higher education in these diverse jurisdictions. The paper, concentrating primarily on Law Departments, reviews the current status of the traditional liberal ideal of university education (Bradnech y 2003, Cownie 2004,) and discusses how its meaning and content are a matter of debate (Maharg 2007, Burridge and Webb 2008). Similar discussions are raised (albeit in a post-colonial paradigm) in South Africa (Cornell 2009). Globally values which highlight the role of universities in expressing national culture, the public good (or goods) and citizenship responsibilities are facing challenges from those private goods which prioritise contributions to economic development and individual advancement. The paper reviews the current legal relationship between the state and the universities in the two countries and its historical evolution as evidenced in official papers, public pronouncements such as parliamentary debates and university mission statements. The argument of the paper is that the evolution of the relationship between the state and the higher education inevitably impacts on the prevailing institutional discourse about the nature of university education. It follows that it would be advantageous for advancing student learning for lecturers and students to appreciate the nationally determined socio- historical and political background which informs the place of higher education in public policy and public perception

Gene Expression Changes in the Mushroom Body of Drosophila melanogaster During a Time Course of Long-Term Memory Formation and Maintenance

Long-term memory (LTM) requires gene transcription. However, there is still much to learn about which genes are transcriptionally regulated during LTM and the biological roles they play. Here, gene expression changes were characterized in Drosophila melanogaster over a time course of LTM formation and maintenance in neurons of the mushroom body (MB), a structure required for normal learning and memory. I identified 120 genes differentially expressed (q \u3c 0.2, fold change \u3e 1.3) 24h after LTM induction. Among these were 13 potential downstream targets for RNA localization by the known memory genes pumilo, staufen and oskar, several genes encoding chromatin regulators and seven genes with cAMP response elements (CRE) that may be regulated by cAMP response element binding (CREB)-mediated transcription. Taken together, the results of this study provide a rich data-set of transcriptionally-regulated LTM candidate genes for further study